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authorAllen Byrne <50328838+byrnHDF@users.noreply.github.com>2022-09-14 20:44:24 (GMT)
committerGitHub <noreply@github.com>2022-09-14 20:44:24 (GMT)
commit45178c87a3099a9fef8bae6f7249ca306cf89629 (patch)
treecb404581365434d641e4d6303921613ef3432bd0 /doxygen/examples
parentdcf3b54b6ef3ffe2093cfae81fe80cdb2bb53047 (diff)
downloadhdf5-45178c87a3099a9fef8bae6f7249ca306cf89629.zip
hdf5-45178c87a3099a9fef8bae6f7249ca306cf89629.tar.gz
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develop Merge doxygen from 1.12 branch (#2095)
Diffstat (limited to 'doxygen/examples')
-rw-r--r--doxygen/examples/H5.format.1.0.html2
-rw-r--r--doxygen/examples/H5.format.1.1.html2
-rw-r--r--doxygen/examples/H5.format.2.0.html25576
-rw-r--r--doxygen/examples/H5.format.html2
-rw-r--r--doxygen/examples/ThreadSafeLibrary.html10
-rw-r--r--doxygen/examples/core_menu.md69
-rw-r--r--doxygen/examples/fortran_menu.md73
-rw-r--r--doxygen/examples/high_level_menu.md30
-rw-r--r--doxygen/examples/java_menu.md84
9 files changed, 13227 insertions, 12621 deletions
diff --git a/doxygen/examples/H5.format.1.0.html b/doxygen/examples/H5.format.1.0.html
index ff21315..4eb0548 100644
--- a/doxygen/examples/H5.format.1.0.html
+++ b/doxygen/examples/H5.format.1.0.html
@@ -139,7 +139,7 @@
<p>This document describes the lower-level data objects;
the higher-level objects and their properties are described
- in the <a href="H5.user.html"><cite>HDF5 User's Guide</cite></a>.
+ in the <a href="H5.user.html"><cite>HDF5 User Guide</cite></a>.
<!--
diff --git a/doxygen/examples/H5.format.1.1.html b/doxygen/examples/H5.format.1.1.html
index 0ae31df..9d03a76 100644
--- a/doxygen/examples/H5.format.1.1.html
+++ b/doxygen/examples/H5.format.1.1.html
@@ -172,7 +172,7 @@ TABLE.list TD { border:none; }
<p>This document describes the lower-level data objects;
the higher-level objects and their properties are described
- in the <a href="H5.user.html"><cite>HDF5 User's Guide</cite></a>.
+ in the <a href="H5.user.html"><cite>HDF5 User Guide</cite></a>.
<P>Three levels of information comprise the file format.
Level 0 contains basic information for identifying and
diff --git a/doxygen/examples/H5.format.2.0.html b/doxygen/examples/H5.format.2.0.html
index c16a3cc..d2979e1 100644
--- a/doxygen/examples/H5.format.2.0.html
+++ b/doxygen/examples/H5.format.2.0.html
@@ -1,289 +1,392 @@
<!DOCTYPE HTML>
<html>
- <head>
- <title>
- HDF5 File Format Specification Version 2.0
- </title>
-
-<style>
-h1 { display: block;
- margin-top: 24px;
- margin-bottom: 24px;
- margin-left: 0px;
- margin-right: 0px;
- text-indent: 0px;
- }
-
-h2 { display: block;
- margin-top: 8x;
- margin-bottom: 8px;
- margin-left: 0px;
- margin-right: 0px;
- text-indent: 0px;
- }
-<!-- A horizontal rule (<hr />) should be placed on the line above
+<head>
+<title>HDF5 File Format Specification Version 2.0</title>
+
+<style type="text/css">
+h1 {
+ display: block;
+ margin-top: 24px;
+ margin-bottom: 24px;
+ margin-left: 0px;
+ margin-right: 0px;
+ text-indent: 0px;
+}
+
+h2 {
+ display: block;
+ margin-top: 8x;
+ margin-bottom: 8px;
+ margin-left: 0px;
+ margin-right: 0px;
+ text-indent: 0px;
+}
+
+<!--
+A horizontal rule ( <hr />) should be placed on the line above
each h2 tag. The h2 tags are used on the main sections along with
-the hr tags. -->
-
-h3 { display: block;
- margin-top: 8px;
- margin-bottom: 8px;
- margin-left: 0px;
- margin-right: 0px;
- text-indent: 0px;
- }
-
-h4 { display: block;
- margin-top: 8px;
- margin-bottom: 8px;
- margin-left: 0px;
- margin-right: 0px;
- text-indent: 0px;
- }
-
-p { display: block;
+the hr tags. -->h3 {
+ display: block;
margin-top: 8px;
margin-bottom: 8px;
margin-left: 0px;
margin-right: 0px;
text-indent: 0px;
- }
+}
+
+h4 {
+ display: block;
+ margin-top: 8px;
+ margin-bottom: 8px;
+ margin-left: 0px;
+ margin-right: 0px;
+ text-indent: 0px;
+}
+
+p {
+ display: block;
+ margin-top: 8px;
+ margin-bottom: 8px;
+ margin-left: 0px;
+ margin-right: 0px;
+ text-indent: 0px;
+}
+
+<!--
+p.item {
+ margin-left: 2em;
+ text-indent: -2em
+}
+
+-->
<!--
-p.item { margin-left: 2em;
- text-indent: -2em
- } -->
-<!-- p.item2 { margin-left: 2em; text-indent: 2em} -->
-
-table.format { border:solid;
- border-collapse:collapse;
- caption-side:top;
- text-align:center;
- width:80%;
- }
-table.format th { border:ridge;
- padding:4px;
- width:25%;
- }
-table.format td { border:ridge;
- padding:4px;
- }
-table.format caption { font-weight:bold;
- font-size:larger;
- }
-
-table.note {border:none;
- text-align:right;
- width:80%;
- }
-
-table.desc { border:solid;
- border-collapse:collapse;
- caption-size:top;
- text-align:left;
- width:80%;
- }
-table.desc tr { vertical-align:top;
- }
-table.desc th { border-style:ridge;
- font-size:larger;
- padding:4px;
- <!-- text-decoration:underline; -->
- }
-table.desc td { border-style:ridge;
- <!-- padding: 4px; -->
- vertical-align:text-top;
- }
-table.desc caption { font-weight:bold;
- font-size:larger;
- }
-
-table.list { border:none;
- width:100%
- }
-table.list tr { vertical-align:text-top;
- }
-table.list th { border:none;
- text-decoration:underline;
- vertical-align:text-top;
- }
-table.list td { border:none;
- vertical-align:text-top;
- }
-
-table.msgdesc { border:none;
- text-align:left;
- width: 80%
- }
-table.msgdesc tr { vertical-align:text-top;
- border-spacing:0;
- padding:0; }
-table.msgdesc th { border:none;
- text-decoration:underline;
- vertical-align:text-top; }
-table.msgdesc td { border:none;
- vertical-align:text-top;
- }
-
-table.list80 { border:none;
- width:80%
- }
-table.list80 tr { vertical-align:text-top;
- }
-table.list80 th { border:none;
- text-decoration:underline;
- vertical-align:text-top;
- }
-table.list80 td { border:none;
- vertical-align:text-top;
- }
-
-table.glossary { border:none;
- text-align:left;
- width: 80%
- }
-table.glossary tr { vertical-align:text-top;
- border-spacing:0;
- padding:0; }
-table.glossary th { border:none;
- text-align:left;
- text-decoration:underline;
- vertical-align:text-top; }
-table.glossary td { border:none;
- text-align:left;
- vertical-align:text-top;
- }
-
-div { page-break-inside:avoid;
- page-break-after:auto
- }
+p.item2 {
+ margin-left: 2em;
+ text-indent: 2em
+}
+-->
+table.format {
+ border: solid;
+ border-collapse: collapse;
+ caption-side: top;
+ text-align: center;
+ width: 80%;
+}
+
+table.format th {
+ border: ridge;
+ padding: 4px;
+ width: 25%;
+}
+
+table.format td {
+ border: ridge;
+ padding: 4px;
+}
+
+table.format caption {
+ font-weight: bold;
+ font-size: larger;
+}
+
+table.note {
+ border: none;
+ text-align: right;
+ width: 80%;
+}
+
+table.desc {
+ border: solid;
+ border-collapse: collapse;
+ caption-size: top;
+ text-align: left;
+ width: 80%;
+}
+
+table.desc tr {
+ vertical-align: top;
+}
+
+table.desc th {
+ border-style: ridge;
+ font-size: larger;
+ padding: 4px; <!--
+ text-decoration: underline;
+ -->
+}
+
+table.desc td {
+ border-style: ridge; <!--
+ padding: 4px; -->
+ vertical-align: text-top;
+}
+
+table.desc caption {
+ font-weight: bold;
+ font-size: larger;
+}
+
+table.list {
+ border: none;
+ width: 100%
+}
+
+table.list tr {
+ vertical-align: text-top;
+}
+
+table.list th {
+ border: none;
+ text-decoration: underline;
+ vertical-align: text-top;
+}
+
+table.list td {
+ border: none;
+ vertical-align: text-top;
+}
+
+table.msgdesc {
+ border: none;
+ text-align: left;
+ width: 80%
+}
+
+table.msgdesc tr {
+ vertical-align: text-top;
+ border-spacing: 0;
+ padding: 0;
+}
+
+table.msgdesc th {
+ border: none;
+ text-decoration: underline;
+ vertical-align: text-top;
+}
+
+table.msgdesc td {
+ border: none;
+ vertical-align: text-top;
+}
+
+table.list80 {
+ border: none;
+ width: 80%
+}
+
+table.list80 tr {
+ vertical-align: text-top;
+}
+
+table.list80 th {
+ border: none;
+ text-decoration: underline;
+ vertical-align: text-top;
+}
+
+table.list80 td {
+ border: none;
+ vertical-align: text-top;
+}
+
+table.glossary {
+ border: none;
+ text-align: left;
+ width: 80%
+}
+
+table.glossary tr {
+ vertical-align: text-top;
+ border-spacing: 0;
+ padding: 0;
+}
+
+table.glossary th {
+ border: none;
+ text-align: left;
+ text-decoration: underline;
+ vertical-align: text-top;
+}
+
+table.glossary td {
+ border: none;
+ text-align: left;
+ vertical-align: text-top;
+}
+
+div {
+ page-break-inside: avoid;
+ page-break-after: auto
+}
</style>
- <center>
+<center>
<table border="0" width="90%">
- <tr>
- <td valign="top">
- <ol type="I">
- <li><a href="#Intro">Introduction</a></li>
- <font size="-1">
- <ol type="A">
- <li><a href="#ThisDocument">This Document</a></li>
- <li><a href="#ChangesForHdf5_1_10">Changes for HDF5 1.10</a></li>
- </ol>
- </font>
-
- <li><a href="#FileMetaData">Disk Format: Level 0 - File Metadata</a></li>
- <font size="-1">
- <ol type="A">
- <li><a href="#Superblock">Disk Format: Level 0A - Format Signature and Superblock</a></li>
- <li><a href="#DriverInfo">Disk Format: Level 0B - File Driver Info</a></li>
- <li><a href="#SuperblockExt">Disk Format: Level 0C - Superblock Extension</a></li>
- </ol>
- </font>
- <li><a href="#FileInfra">Disk Format: Level 1 - File Infrastructure</a></li>
- <font size="-1">
- <ol type="A">
- <li><a href="#Btrees">Disk Format: Level 1A - B-trees and B-tree
- Nodes</a></li>
- <ol type="1">
- <li><a href="#V1Btrees">Disk Format: Level 1A1 - Version 1
- B-trees (B-link Trees)</a></li>
- <li><a href="#V2Btrees">Disk Format: Level 1A2 - Version 2
- B-trees</a></li>
- </ol>
- <li><a href="#SymbolTable">Disk Format: Level 1B - Group Symbol Table Nodes</a></li>
- <li><a href="#SymbolTableEntry">Disk Format: Level 1C - Symbol Table Entry</a></li>
- <li><a href="#LocalHeap">Disk Format: Level 1D - Local Heaps</a></li>
- <li><a href="#GlobalHeap">Disk Format: Level 1E - Global Heap</a></li>
- <li><a href="#FractalHeap">Disk Format: Level 1F - Fractal Heap</a></li>
- <li><a href="#FreeSpaceManager">Disk Format: Level 1G - Free-space Manager</a></li>
- <li><a href="#SOHMTable">Disk Format: Level 1H - Shared Object Header Message Table</a></li>
- </ol>
- </font>
- <li><a href="#DataObject">Disk Format: Level 2 - Data Objects</a></li>
- <font size="-1">
- <ol type="A">
- <li><a href="#ObjectHeader">Disk Format: Level 2A - Data Object Headers</a></li>
- <ol type="1">
- <li><a href="#ObjectHeaderPrefix">Disk Format: Level 2A1 - Data Object Header Prefix</a></li>
- <ol type="a">
- <li><a href="#V1ObjectHeaderPrefix">Version 1 Data Object Header Prefix</a></li>
- <li><a href="#V2ObjectHeaderPrefix">Version 2 Data Object Header Prefix</a></li>
- </ol>
- <li><a href="#ObjectHeaderMessages">Disk Format: Level 2A2 - Data Object Header Messages</a></li>
- <ol type="a">
- <li><a href="#NILMessage">The NIL Message</a></li> <!-- 0x0000 -->
- <li><a href="#DataspaceMessage">The Dataspace Message</a></li> <!-- 0x0001 -->
- <li><a href="#LinkInfoMessage">The Link Info Message</a></li> <!-- 0x0002 -->
+ <tr>
+ <td valign="top">
+ <ol type="I">
+ <li><a href="#Intro">Introduction</a></li>
+ <font size="-1">
+ <ol type="A">
+ <li><a href="#ThisDocument">This Document</a></li>
+ <li><a href="#ChangesForHdf5_1_10">Changes for HDF5 1.10</a></li>
+ </ol>
+ </font>
+
+ <li><a href="#FileMetaData">Disk Format: Level 0 - File
+ Metadata</a></li>
+ <font size="-1">
+ <ol type="A">
+ <li><a href="#Superblock">Disk Format: Level 0A - Format
+ Signature and Superblock</a></li>
+ <li><a href="#DriverInfo">Disk Format: Level 0B - File
+ Driver Info</a></li>
+ <li><a href="#SuperblockExt">Disk Format: Level 0C -
+ Superblock Extension</a></li>
+ </ol>
+ </font>
+ <li><a href="#FileInfra">Disk Format: Level 1 - File
+ Infrastructure</a></li>
+ <font size="-1">
+ <ol type="A">
+ <li><a href="#Btrees">Disk Format: Level 1A - B-trees
+ and B-tree Nodes</a></li>
+ <ol type="1">
+ <li><a href="#V1Btrees">Disk Format: Level 1A1 -
+ Version 1 B-trees (B-link Trees)</a></li>
+ <li><a href="#V2Btrees">Disk Format: Level 1A2 -
+ Version 2 B-trees</a></li>
+ </ol>
+ <li><a href="#SymbolTable">Disk Format: Level 1B - Group
+ Symbol Table Nodes</a></li>
+ <li><a href="#SymbolTableEntry">Disk Format: Level 1C -
+ Symbol Table Entry</a></li>
+ <li><a href="#LocalHeap">Disk Format: Level 1D - Local
+ Heaps</a></li>
+ <li><a href="#GlobalHeap">Disk Format: Level 1E - Global
+ Heap</a></li>
+ <li><a href="#FractalHeap">Disk Format: Level 1F -
+ Fractal Heap</a></li>
+ <li><a href="#FreeSpaceManager">Disk Format: Level 1G -
+ Free-space Manager</a></li>
+ <li><a href="#SOHMTable">Disk Format: Level 1H - Shared
+ Object Header Message Table</a></li>
+ </ol>
+ </font>
+ <li><a href="#DataObject">Disk Format: Level 2 - Data
+ Objects</a></li>
+ <font size="-1">
+ <ol type="A">
+ <li><a href="#ObjectHeader">Disk Format: Level 2A - Data
+ Object Headers</a></li>
+ <ol type="1">
+ <li><a href="#ObjectHeaderPrefix">Disk Format: Level
+ 2A1 - Data Object Header Prefix</a></li>
+ <ol type="a">
+ <li><a href="#V1ObjectHeaderPrefix">Version 1 Data
+ Object Header Prefix</a></li>
+ <li><a href="#V2ObjectHeaderPrefix">Version 2 Data
+ Object Header Prefix</a></li>
+ </ol>
+ <li><a href="#ObjectHeaderMessages">Disk Format: Level
+ 2A2 - Data Object Header Messages</a></li>
+ <ol type="a">
+ <li><a href="#NILMessage">The NIL Message</a></li>
+ <!-- 0x0000 -->
+ <li><a href="#DataspaceMessage">The Dataspace Message</a></li>
+ <!-- 0x0001 -->
+ <li><a href="#LinkInfoMessage">The Link Info Message</a></li>
+ <!-- 0x0002 -->
+ </ol>
+ </ol>
+ </ol>
+ </font>
</ol>
- </ol>
- </ol>
- </font>
- </ol>
- </td>
-
- <td>&nbsp;</td>
-
- <td valign="top">
- <ol type="I" start="4">
- <li><a href="#DataObject">Disk Format: Level 2 - Data
- Objects</a><font size="-1"><i> (Continued)</i></li>
- <ol type="A">
- <li><a href="#ObjectHeader">Disk Format: Level 2A - Data Object
- Headers</a><i> (Continued)</i></li>
- <ol type="1" start="2">
- <li><a href="#ObjectHeaderMessages">Disk Format: Level 2A2 -
- Data Object Header Messages</a><i> (Continued)</i></li>
- <ol type="a" start="4">
- <li><a href="#DatatypeMessage">The Datatype Message</a></li> <!-- 0x0003 -->
- <li><a href="#OldFillValueMessage">The Data Storage -
- Fill Value (Old) Message</a></li> <!-- 0x0004 -->
- <li><a href="#FillValueMessage">The Data Storage -
- Fill Value Message</a></li> <!-- 0x0005 -->
- <li><a href="#LinkMessage">The Link Message</a></li> <!-- 0x0006 -->
- <li><a href="#ExternalFileListMessage">The Data Storage -
- External Data Files Message</a></li> <!-- 0x0007 -->
- <li><a href="#LayoutMessage">The Data Storage -
- Layout Message</a></li> <!-- 0x0008 -->
- <li><a href="#BogusMessage">The Bogus Message</a></li> <!-- 0x0009 -->
- <li><a href="#GroupInfoMessage">The Group Info
- Message</a></li> <!-- 0x000a -->
- <li><a href="#FilterMessage">The Data Storage -
- Filter Pipeline Message</a></li> <!-- 0x000b -->
- <li><a href="#AttributeMessage">The Attribute
- Message</a></li> <!-- 0x000c -->
- <li><a href="#CommentMessage">The Object Comment
- Message</a></li> <!-- 0x000d -->
- <li><a href="#OldModificationTimeMessage">The Object
- Modification Time (Old) Message</a></li> <!-- 0x000e -->
- <li><a href="#SOHMTableMessage">The Shared Message
- Table Message</a></li> <!-- 0x000f -->
- <li><a href="#ContinuationMessage">The Object Header
- Continuation Message</a></li> <!-- 0x0010 -->
- <li><a href="#SymbolTableMessage">The Symbol
- Table Message</a></li> <!-- 0x0011 -->
- <li><a href="#ModificationTimeMessage">The Object
- Modification Time Message</a></li> <!-- 0x0012 -->
- <li><a href="#BtreeKValuesMessage">The B-tree
- &lsquo;K&rsquo; Values Message</a></li> <!-- 0x0013 -->
- <li><a href="#DrvInfoMessage">The Driver Info
- Message</a></li> <!-- 0x0014 -->
- <li><a href="#AinfoMessage">The Attribute Info
- Message</a></li> <!-- 0x0015 -->
- <li><a href="#RefCountMessage">The Object Reference
- Count Message</a></li> <!-- 0x0016 -->
- <li><a href="#FsinfoMessage">The File Space Info
- Message</a></li> <!-- 0x0018 -->
+ </td>
+
+ <td>&nbsp;</td>
+
+ <td valign="top">
+ <ol type="I" start="4">
+ <li><a href="#DataObject">Disk Format: Level 2 - Data
+ Objects</a><font size="-1"><i> (Continued)</i></font></li>
+ <ol type="A">
+ <li><a href="#ObjectHeader">Disk Format: Level 2A - Data
+ Object Headers</a><i> (Continued)</i></li>
+ <ol type="1" start="2">
+ <li><a href="#ObjectHeaderMessages">Disk Format: Level
+ 2A2 - Data Object Header Messages</a><i> (Continued)</i></li>
+ <ol type="a" start="4">
+ <li><a href="#DatatypeMessage">The Datatype Message</a></li>
+ <!-- 0x0003 -->
+ <li><a href="#OldFillValueMessage">The Data Storage -
+ Fill Value (Old) Message</a></li>
+ <!-- 0x0004 -->
+ <li><a href="#FillValueMessage">The Data Storage - Fill
+ Value Message</a></li>
+ <!-- 0x0005 -->
+ <li><a href="#LinkMessage">The Link Message</a></li>
+ <!-- 0x0006 -->
+ <li><a href="#ExternalFileListMessage">The Data Storage
+ - External Data Files Message</a></li>
+ <!-- 0x0007 -->
+ <li><a href="#LayoutMessage">The Data Storage - Layout
+ Message</a></li>
+ <!-- 0x0008 -->
+ <li><a href="#BogusMessage">The Bogus Message</a></li>
+ <!-- 0x0009 -->
+ <li><a href="#GroupInfoMessage">The Group Info Message</a></li>
+ <!-- 0x000a -->
+ <li><a href="#FilterMessage">The Data Storage - Filter
+ Pipeline Message</a></li>
+ <!-- 0x000b -->
+ <li><a href="#AttributeMessage">The Attribute Message</a></li>
+ <!-- 0x000c -->
+ <li><a href="#CommentMessage">The Object Comment
+ Message</a></li>
+ <!-- 0x000d -->
+ <li><a href="#OldModificationTimeMessage">The Object
+ Modification Time (Old) Message</a></li>
+ <!-- 0x000e -->
+ <li><a href="#SOHMTableMessage">The Shared Message
+ Table Message</a></li>
+ <!-- 0x000f -->
+ <li><a href="#ContinuationMessage">The Object Header
+ Continuation Message</a></li>
+ <!-- 0x0010 -->
+ <li><a href="#SymbolTableMessage">The Symbol Table
+ Message</a></li>
+ <!-- 0x0011 -->
+ <li><a href="#ModificationTimeMessage">The Object
+ Modification Time Message</a></li>
+ <!-- 0x0012 -->
+ <li><a href="#BtreeKValuesMessage">The B-tree
+ &lsquo;K&rsquo; Values Message</a></li>
+ <!-- 0x0013 -->
+ <li><a href="#DrvInfoMessage">The Driver Info Message</a></li>
+ <!-- 0x0014 -->
+ <li><a href="#AinfoMessage">The Attribute Info Message</a></li>
+ <!-- 0x0015 -->
+ <li><a href="#RefCountMessage">The Object Reference
+ Count Message</a></li>
+ <!-- 0x0016 -->
+ <li><a href="#FsinfoMessage">The File Space Info
+ Message</a></li>
+ <!-- 0x0018 -->
+ </ol>
+ </ol>
+ <li><a href="#DataStorage">Disk Format: Level 2B - Data
+ Object Data Storage</a></li>
+ </ol>
+ <font></font>
+ <li><a href="#AppendixA">Appendix A: Definitions</a></li>
+ <li><a href="#AppendixB">Appendix B: File Memory
+ Allocation Types</a></li>
</ol>
- </ol>
- <li><a href="#DataStorage">Disk Format: Level 2B - Data Object Data Storage</a></li>
- </ol>
- </font>
- <li><a href="#AppendixA">Appendix A: Definitions</a></li>
- <li><a href="#AppendixB">Appendix B: File Memory Allocation Types</a></li>
- </ol>
-</td></tr>
-</table>
+ </td>
+ </tr>
+ </table>
</center>
@@ -293,949 +396,984 @@ div { page-break-inside:avoid;
<hr />
<a name="Intro"><h2>I. Introduction</h2></a>
- <table align="right" width="100">
- <tr><td>&nbsp;</td><td align="center">
- <hr />
- <img src="FF-IH_FileGroup.gif" alt="HDF5 Groups" hspace="15" vspace="15">
- </td><td>&nbsp;</td></tr>
- <tr><td>&nbsp;</td><td align="center">
- <strong>Figure 1:</strong> Relationships among the HDF5 root group, other groups, and objects
- <hr />
- </td><td>&nbsp;</td></tr>
-
- <tr><td>&nbsp;</td><td align="center">
- <img src="FF-IH_FileObject.gif" alt="HDF5 Objects" hspace="15" vspace="15">
- </td><td>&nbsp;</td></tr>
- <tr><td>&nbsp;</td><td align="center">
- <strong>Figure 2:</strong> HDF5 objects -- datasets, datatypes, or dataspaces
- <hr />
- </td><td>&nbsp;</td></tr>
- </table>
-
-
- <p>The format of an HDF5 file on disk encompasses several
- key ideas of the HDF4 and AIO file formats as well as
- addressing some shortcomings therein. The new format is
- more self-describing than the HDF4 format and is more
- uniformly applied to data objects in the file.</p>
-
- <p>An HDF5 file appears to the user as a directed graph.
- The nodes of this graph are the higher-level HDF5 objects
- that are exposed by the HDF5 APIs:</p>
-
- <ul>
- <li>Groups</li>
- <li>Datasets</li>
- <li>Committed (formerly Named) datatypes</li>
- </ul>
-
- <p>At the lowest level, as information is actually written to the disk,
- an HDF5 file is made up of the following objects:</p>
- <ul>
- <li>A superblock</li>
- <li>B-tree nodes</li>
- <li>Heap blocks</li>
- <li>Object headers</li>
- <li>Object data</li>
- <li>Free space</li>
- </ul>
-
- <p>The HDF5 Library uses these low-level objects to represent the
- higher-level objects that are then presented to the user or
- to applications through the APIs. For instance, a group is an
- object header that contains a message that points to a local
- heap (for storing the links to objects in the group) and to a
- B-tree (which indexes the links). A dataset is an object header
- that contains messages that describe datatype, dataspace, layout,
- filters, external files, fill value, and other elements with the
- layout message pointing to either a raw data chunk or to a
- B-tree that points to raw data chunks.</p>
+<table align="right" width="100">
+ <tr>
+ <td>&nbsp;</td>
+ <td align="center">
+ <hr /> <img src="FF-IH_FileGroup.gif" alt="HDF5 Groups" hspace="15"
+ vspace="15">
+ </td>
+ <td>&nbsp;</td>
+ </tr>
+ <tr>
+ <td>&nbsp;</td>
+ <td align="center"><strong>Figure 1:</strong> Relationships among
+ the HDF5 root group, other groups, and objects
+ <hr /></td>
+ <td>&nbsp;</td>
+ </tr>
+
+ <tr>
+ <td>&nbsp;</td>
+ <td align="center"><img src="FF-IH_FileObject.gif"
+ alt="HDF5 Objects" hspace="15" vspace="15"></td>
+ <td>&nbsp;</td>
+ </tr>
+ <tr>
+ <td>&nbsp;</td>
+ <td align="center"><strong>Figure 2:</strong> HDF5 objects --
+ datasets, datatypes, or dataspaces
+ <hr /></td>
+ <td>&nbsp;</td>
+ </tr>
+</table>
+
+
+<p>The format of an HDF5 file on disk encompasses several key ideas
+ of the HDF4 and AIO file formats as well as addressing some
+ shortcomings therein. The new format is more self-describing than the
+ HDF4 format and is more uniformly applied to data objects in the file.</p>
+
+<p>An HDF5 file appears to the user as a directed graph. The nodes
+ of this graph are the higher-level HDF5 objects that are exposed by the
+ HDF5 APIs:</p>
+
+<ul>
+ <li>Groups</li>
+ <li>Datasets</li>
+ <li>Committed (formerly Named) datatypes</li>
+</ul>
+
+<p>At the lowest level, as information is actually written to the
+ disk, an HDF5 file is made up of the following objects:</p>
+<ul>
+ <li>A superblock</li>
+ <li>B-tree nodes</li>
+ <li>Heap blocks</li>
+ <li>Object headers</li>
+ <li>Object data</li>
+ <li>Free space</li>
+</ul>
+
+<p>The HDF5 Library uses these low-level objects to represent the
+ higher-level objects that are then presented to the user or to
+ applications through the APIs. For instance, a group is an object
+ header that contains a message that points to a local heap (for storing
+ the links to objects in the group) and to a B-tree (which indexes the
+ links). A dataset is an object header that contains messages that
+ describe datatype, dataspace, layout, filters, external files, fill
+ value, and other elements with the layout message pointing to either a
+ raw data chunk or to a B-tree that points to raw data chunks.</p>
<br />
<a name="ThisDocument"><h3>I.A. This Document</h3></a>
- <p>This document describes the lower-level data objects;
- the higher-level objects and their properties are described
- in the <a href="UG/HDF5_Users_Guide-Responsive HTML5/index.html"><cite>HDF5 User&rsquo;s Guide</cite></a>.</p>
-
- <p>Three levels of information comprise the file format.
- Level 0 contains basic information for identifying and
- defining information about the file. Level 1 information contains
- the information about the pieces of a file shared by many objects
- in the file (such as a B-trees and heaps). Level 2 is the rest
- of the file and contains all of the data objects, with each object
- partitioned into header information, also known as
- <em>metadata</em>, and data.</p>
-
- <p>The sizes of various fields in the following layout tables are
- determined by looking at the number of columns the field spans
- in the table. There are three exceptions: (1) The size may be
- overridden by specifying a size in parentheses, (2) the size of
- addresses is determined by the <em>Size of Offsets</em> field
- in the superblock and is indicated in this document with a
- superscripted &lsquo;O&rsquo;, and (3) the size of length fields is determined
- by the <em>Size of Lengths</em> field in the superblock and is
- indicated in this document with a superscripted &lsquo;L&rsquo;.</p>
-
- <p>Values for all fields in this document should be treated as unsigned
- integers, unless otherwise noted in the description of a field.
- Additionally, all metadata fields are stored in little-endian byte
- order.
- </p>
-
- <p>All checksums used in the format are computed with the
- <a href="http://www.burtleburtle.net/bob/hash/doobs.html">Jenkins&rsquo;
- lookup3</a> algorithm.
- </p>
-
- <p>Whenever a bit flag or field is mentioned for an entry, bits are
- numbered from the lowest bit position in the entry.
- </p>
-
- <p>Various tables in this document aligned with &ldquo;This space inserted
- only to align table nicely&rdquo;. These entries in the table are just
- to make the table presentation nicer and do not represent any values
- or padding in the file.
- </p>
+<p>
+ This document describes the lower-level data objects; the higher-level
+ objects and their properties are described in the <a
+ href="UG/HDF5_User_Guide-Responsive HTML5/index.html"><cite>HDF5
+ User Guide</cite></a>.
+</p>
+
+<p>
+ Three levels of information comprise the file format. Level 0 contains
+ basic information for identifying and defining information about the
+ file. Level 1 information contains the information about the pieces of
+ a file shared by many objects in the file (such as a B-trees and
+ heaps). Level 2 is the rest of the file and contains all of the data
+ objects, with each object partitioned into header information, also
+ known as <em>metadata</em>, and data.
+</p>
+
+<p>
+ The sizes of various fields in the following layout tables are
+ determined by looking at the number of columns the field spans in the
+ table. There are three exceptions: (1) The size may be overridden by
+ specifying a size in parentheses, (2) the size of addresses is
+ determined by the <em>Size of Offsets</em> field in the superblock and
+ is indicated in this document with a superscripted &lsquo;O&rsquo;, and
+ (3) the size of length fields is determined by the <em>Size of
+ Lengths</em> field in the superblock and is indicated in this document with
+ a superscripted &lsquo;L&rsquo;.
+</p>
+
+<p>Values for all fields in this document should be treated as
+ unsigned integers, unless otherwise noted in the description of a
+ field. Additionally, all metadata fields are stored in little-endian
+ byte order.</p>
+
+<p>
+ All checksums used in the format are computed with the <a
+ href="http://www.burtleburtle.net/bob/hash/doobs.html">Jenkins&rsquo;
+ lookup3</a> algorithm.
+</p>
+
+<p>Whenever a bit flag or field is mentioned for an entry, bits are
+ numbered from the lowest bit position in the entry.</p>
+
+<p>Various tables in this document aligned with &ldquo;This space
+ inserted only to align table nicely&rdquo;. These entries in the table
+ are just to make the table presentation nicer and do not represent any
+ values or padding in the file.</p>
<br />
<a name="ChangesForHdf5_1_10"><h3>I.B. Changes for HDF5 1.10</h3></a>
- <p>As of October 2015, changes in the file format for HDF5 1.10
- have not yet been finalized.</p>
+<p>As of October 2015, changes in the file format for HDF5 1.10 have
+ not yet been finalized.</p>
<br />
<br />
<hr />
-<h2><a name="FileMetaData">
-II. Disk Format: Level 0 - File Metadata</a></h2>
-
-<br />
-<h3><a name="Superblock">
-II.A. Disk Format: Level 0A - Format Signature and Superblock</a></h3>
-
- <p>The superblock may begin at certain predefined offsets within
- the HDF5 file, allowing a block of unspecified content for
- users to place additional information at the beginning (and
- end) of the HDF5 file without limiting the HDF5 Library&rsquo;s
- ability to manage the objects within the file itself. This
- feature was designed to accommodate wrapping an HDF5 file in
- another file format or adding descriptive information to an HDF5
- file without requiring the modification of the actual file&rsquo;s
- information. The superblock is located by searching for the
- HDF5 format signature at byte offset 0, byte offset 512, and at
- successive locations in the file, each a multiple of two of
- the previous location; in other words, at these byte offsets:
- 0, 512, 1024, 2048, and so on.</p>
-
- <p>The superblock is composed of the format signature, followed by a
- superblock version number and information that is specific to each
- version of the superblock.
- Currently, there are three versions of the superblock format.
- Version 0 is the default format, while version 1 is basically the same
- as version 0 with additional information when a non-default B-tree &lsquo;K&rsquo;
- value is stored. Version 2 is the latest format, with some fields
- eliminated or compressed and with superblock extension and checksum
- support.</p>
-
- <p>Version 0 and 1 of the superblock are described below:</p>
-
-
- <div align="center">
- <table class="format">
- <caption>
- Superblock (Versions 0 and 1)
- </caption>
-
- <tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
-
- <tr>
- <td colspan="4"><br />Format Signature (8 bytes)<br /><br /></td>
- </tr>
-
- <tr>
- <td>Version # of Superblock</td>
- <td>Version # of File&rsquo;s Free Space Storage</td>
- <td>Version # of Root Group Symbol Table Entry</td>
- <td>Reserved (zero)</td>
- </tr>
-
- <tr>
- <td>Version # of Shared Header Message Format</td>
- <td>Size of Offsets</td>
- <td>Size of Lengths</td>
- <td>Reserved (zero)</td>
- </tr>
-
- <tr>
- <td colspan="2">Group Leaf Node K</td>
- <td colspan="2">Group Internal Node K</td>
- </tr>
-
- <tr>
- <td colspan="4">File Consistency Flags</td>
- </tr>
-
- <tr>
- <td colspan="2" style="border:dotted;">Indexed Storage Internal Node K<sup>1</sup></td>
- <td colspan="2" style="border:dotted;">Reserved (zero)<sup>1</sup></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Base Address<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Address of File Free space Info<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />End of File Address<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Driver Information Block Address<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4">Root Group Symbol Table Entry</td>
- </tr>
- </table>
+<h2>
+ <a name="FileMetaData"> II. Disk Format: Level 0 - File Metadata</a>
+</h2>
+
+<br />
+<h3>
+ <a name="Superblock"> II.A. Disk Format: Level 0A - Format
+ Signature and Superblock</a>
+</h3>
+
+<p>The superblock may begin at certain predefined offsets within the
+ HDF5 file, allowing a block of unspecified content for users to place
+ additional information at the beginning (and end) of the HDF5 file
+ without limiting the HDF5 Library&rsquo;s ability to manage the objects
+ within the file itself. This feature was designed to accommodate
+ wrapping an HDF5 file in another file format or adding descriptive
+ information to an HDF5 file without requiring the modification of the
+ actual file&rsquo;s information. The superblock is located by searching
+ for the HDF5 format signature at byte offset 0, byte offset 512, and at
+ successive locations in the file, each a multiple of two of the
+ previous location; in other words, at these byte offsets: 0, 512, 1024,
+ 2048, and so on.</p>
+
+<p>The superblock is composed of the format signature, followed by a
+ superblock version number and information that is specific to each
+ version of the superblock. Currently, there are three versions of the
+ superblock format. Version 0 is the default format, while version 1 is
+ basically the same as version 0 with additional information when a
+ non-default B-tree &lsquo;K&rsquo; value is stored. Version 2 is the
+ latest format, with some fields eliminated or compressed and with
+ superblock extension and checksum support.</p>
+
+<p>Version 0 and 1 of the superblock are described below:</p>
+
+
+<div align="center">
+ <table class="format">
+ <caption>Superblock (Versions 0 and 1)</caption>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are
- of the size specified in &ldquo;Size of Offsets.&rdquo;)
- </td></tr>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ </tr>
+
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with a &lsquo;1&rsquo; in the above table are
- new in version 1 of the superblock)
- </td></tr>
- </table>
- </div>
+ <td colspan="4"><br />Format Signature (8 bytes)<br />
+ <br /></td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Format Signature</p></td>
- <td><p>This field contains a constant value and can be used to
- quickly identify a file as being an HDF5 file. The
- constant value is designed to allow easy identification of
- an HDF5 file and to allow certain types of data corruption
- to be detected. The file signature of an HDF5 file always
- contains the following values:</p>
- <center>
- <table border align="center" cellpadding="4">
- <tr align="center">
- <td align="right">Decimal:</td>
- <td width="8%">137</td>
- <td width="8%">72</td>
- <td width="8%">68</td>
- <td width="8%">70</td>
- <td width="8%">13</td>
- <td width="8%">10</td>
- <td width="8%">26</td>
- <td width="8%">10</td>
- </tr>
-
- <tr align="center">
- <td align="right">Hexadecimal:</td>
- <td>89</td>
- <td>48</td>
- <td>44</td>
- <td>46</td>
- <td>0d</td>
- <td>0a</td>
- <td>1a</td>
- <td>0a</td>
- </tr>
-
- <tr align="center">
- <td align="right">ASCII C Notation:</td>
- <td>\211</td>
- <td>H</td>
- <td>D</td>
- <td>F</td>
- <td>\r</td>
- <td>\n</td>
- <td>\032</td>
- <td>\n</td>
- </tr>
- </table>
- </center>
- <p>This signature both identifies the file as an HDF5 file
- and provides for immediate detection of common
- file-transfer problems. The first two bytes distinguish
- HDF5 files on systems that expect the first two bytes to
- identify the file type uniquely. The first byte is
- chosen as a non-ASCII value to reduce the probability
- that a text file may be misrecognized as an HDF5 file;
- also, it catches bad file transfers that clear bit
- 7. Bytes two through four name the format. The CR-LF
- sequence catches bad file transfers that alter newline
- sequences. The control-Z character stops file display
- under MS-DOS. The final line feed checks for the inverse
- of the CR-LF translation problem. (This is a direct
- descendent of the
- <a href="http://www.libpng.org/pub/png/spec/iso/index-object.html#5PNG-file-signature">PNG</a> file
- signature.)</p>
- <p><em>This field is present in version 0+ of the superblock.</em>
- </p></td>
- </tr>
-
- <tr>
- <td><p>Version Number of the Superblock</p></td>
- <td><p>This value is used to determine the format of the
- information in the superblock. When the format of the
- information in the superblock is changed, the version number
- is incremented to the next integer and can be used to
- determine how the information in the superblock is
- formatted.</p>
-
- <p>Values of 0, 1 and 2 are defined for this field. (The format
- of version 2 is described below, not here)
- </p>
-
- <p><em>This field is present in version 0+ of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Version Number of the File&rsquo;s Free Space
- Information</p></td>
- <td>
- <p>This value is used to determine the format of the
- file&rsquo;s free space information.
- </p>
- <p>The only value currently valid in this field is &lsquo;0&rsquo;, which
- indicates that the file&rsquo;s free space is as described
- <a href="#FreeSpaceManager">below</a>.
- </p>
-
- <p><em>This field is present in version 0 and 1 of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Version Number of the Root Group Symbol Table
- Entry</p></td>
- <td><p>This value is used to determine the format of the
- information in the Root Group Symbol Table Entry. When the
- format of the information in that field is changed, the
- version number is incremented to the next integer and can be
- used to determine how the information in the field
- is formatted.</p>
- <p>The only value currently valid in this field is &lsquo;0&rsquo;,
- which indicates that the root group symbol table entry is
- formatted as described <a href="#SymbolTableEntry">below</a>.</p>
- <p><em>This field is present in version 0 and 1 of the
- superblock.</em></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Version Number of the Shared Header Message Format</p></td>
- <td><p>This value is used to determine the format of the
- information in a shared object header message. Since the format
- of the shared header messages differs from the other private
- header messages, a version number is used to identify changes
- in the format.
- </p>
- <p>The only value currently valid in this field is &lsquo;0&rsquo;, which
- indicates that shared header messages are formatted as
- described <a href="#ObjectHeaderMessages">below</a>.
- </p>
-
- <p><em>This field is present in version 0 and 1 of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Size of Offsets</p></td>
- <td><p>This value contains the number of bytes used to store
- addresses in the file. The values for the addresses of
- objects in the file are offsets relative to a base address,
- usually the address of the superblock signature. This
- allows a wrapper to be added after the file is created
- without invalidating the internal offset locations.
- </p>
-
- <p><em>This field is present in version 0+ of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Size of Lengths</p></td>
- <td><p>This value contains the number of bytes used to store
- the size of an object.
- </p>
- <p><em>This field is present in version 0+ of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Group Leaf Node K</p></td>
- <td>
- <p>Each leaf node of a group B-tree will have at
- least this many entries but not more than twice this
- many. If a group has a single leaf node then it
- may have fewer entries.
- </p>
- <p>This value must be greater than zero.
- </p>
- <p>See the <a href="#Btrees">description</a> of B-trees below.
- </p>
-
- <p><em>This field is present in version 0 and 1 of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Group Internal Node K</p></td>
- <td>
- <p>Each internal node of a group B-tree will have at
- least this many entries but not more than twice this
- many. If the group has only one internal
- node then it might have fewer entries.
- </p>
- <p>This value must be greater than zero.
- </p>
- <p>See the <a href="#Btrees">description</a> of B-trees below.
- </p>
-
- <p><em>This field is present in version 0 and 1 of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>File Consistency Flags</p></td>
- <td>
- <p>This value contains flags to indicate information
- about the consistency of the information contained
- within the file. Currently, the following bit flags are
- defined:
- <ul>
- <li>Bit 0 set indicates that the file is opened for
- write-access.</li>
- <li>Bit 1 set indicates that the file has
- been verified for consistency and is guaranteed to be
- consistent with the format defined in this document.</li>
- <li>Bits 2-31 are reserved for future use.</li>
- </ul>
- Bit 0 should be
- set as the first action when a file is opened for write
- access and should be cleared only as the final action
- when closing a file. Bit 1 should be cleared during
- normal access to a file and only set after the file&rsquo;s
- consistency is guaranteed by the library or a
- consistency utility.
- </p>
-
- <p><em>This field is present in version 0+ of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Indexed Storage Internal Node K</p></td>
- <td>
- <p>Each internal node of an indexed storage B-tree will have at
- least this many entries but not more than twice this
- many. If the index storage B-tree has only one internal
- node then it might have fewer entries.
- </p>
- <p>This value must be greater than zero.
- </p>
- <p>See the <a href="#Btrees">description</a> of B-trees below.
- </p>
-
- <p><em>This field is present in version 1 of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Base Address</p></td>
- <td>
- <p>This is the absolute file address of the first byte of
- the HDF5 data within the file. The library currently
- constrains this value to be the absolute file address
- of the superblock itself when creating new files;
- future versions of the library may provide greater
- flexibility. When opening an existing file and this address does
- not match the offset of the superblock, the library assumes
- that the entire contents of the HDF5 file have been adjusted in
- the file and adjusts the base address and end of file address to
- reflect their new positions in the file. Unless otherwise noted,
- all other file addresses are relative to this base
- address.
- </p>
-
- <p><em>This field is present in version 0+ of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Address of Global Free-space Index</p></td>
- <td>
- <p>The file&rsquo;s free space is not persistent for version 0 and 1 of
- the superblock.
- Currently this field always contains the
- <a href="#UndefinedAddress">undefined address</a>.
- </p>
-
- <p><em>This field is present in version 0 and 1 of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>End of File Address</p></td>
- <td>
- <p>This is the absolute file address of the first byte past
- the end of all HDF5 data. It is used to determine whether a
- file has been accidentally truncated and as an address where
- file data allocation can occur if space from the free list is
- not used.
- </p>
-
- <p><em>This field is present in version 0+ of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Driver Information Block Address</p></td>
- <td>
- <p>This is the relative file address of the file driver
- information block which contains driver-specific
- information needed to reopen the file. If there is no
- driver information block then this entry should be the
- <a href="#UndefinedAddress">undefined address</a>.
- </p>
-
- <p><em>This field is present in version 0 and 1 of the superblock.</em>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Root Group Symbol Table Entry</p></td>
- <td>
- <p>This is the <a href="#SymbolTableEntry">symbol table entry</a>
- of the root group, which serves as the entry point into
- the group graph for the file.
- </p>
-
- <p><em>This field is present in version 0 and 1 of the superblock.</em>
- </p>
- </td>
+ <tr>
+ <td>Version # of Superblock</td>
+ <td>Version # of File&rsquo;s Free Space Storage</td>
+ <td>Version # of Root Group Symbol Table Entry</td>
+ <td>Reserved (zero)</td>
</tr>
- </table>
- </div>
- <br />
- <p>Version 2 of the superblock is described below:</p>
-
- <div align="center">
- <table class="format">
- <caption>
- Superblock (Version 2)
- </caption>
-
- <tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
-
- <tr>
- <td colspan="4"><br />Format Signature (8 bytes)<br /><br /></td>
- </tr>
-
- <tr>
- <td>Version # of Superblock</td>
- <td>Size of Offsets</td>
- <td>Size of Lengths</td>
- <td>File Consistency Flags</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Base Address<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Superblock Extension Address<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />End of File Address<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Root Group Object Header Address<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4">Superblock Checksum</td>
- </tr>
- </table>
+ <tr>
+ <td>Version # of Shared Header Message Format</td>
+ <td>Size of Offsets</td>
+ <td>Size of Lengths</td>
+ <td>Reserved (zero)</td>
+ </tr>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are
- of the size specified in &ldquo;Size of Offsets.&rdquo;)
- </td></tr>
- </table>
+ <td colspan="2">Group Leaf Node K</td>
+ <td colspan="2">Group Internal Node K</td>
+ </tr>
- </div>
+ <tr>
+ <td colspan="4">File Consistency Flags</td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Format Signature</p></td>
- <td>
- <p>This field is the same as described for versions 0 and 1 of the
- superblock.
- </p></td>
- </tr>
-
- <tr>
- <td><p>Version Number of the Superblock</p></td>
- <td>
- <p>This field has a value of 2 and has the same meaning as for
- versions 0 and 1.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Size of Offsets</p></td>
- <td>
- <p>This field is the same as described for versions 0 and 1 of the
- superblock.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Size of Lengths</p></td>
- <td>
- <p>This field is the same as described for versions 0 and 1 of the
- superblock.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>File Consistency Flags</p></td>
- <td>
- <p>This field is the same as described for versions 0 and 1 except
- that it is smaller (the number of reserved bits has been reduced
- from 30 to 6).
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Base Address</p></td>
- <td>
- <p>This field is the same as described for versions 0 and 1 of the
- superblock.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Superblock Extension Address</p></td>
- <td>
- <p>The field is the address of the object header for the
- <a href="#SuperblockExt">superblock extension</a>.
- If there is no extension then this entry should be the
- <a href="#UndefinedAddress">undefined address</a>.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>End of File Address</p></td>
- <td>
- <p>This field is the same as described for versions 0 and 1 of the
- superblock.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Root Group Object Header Address</p></td>
- <td>
- <p>This is the address of
- the <a href="#DataObject">root group object header</a>,
- which serves as the entry point into the group graph for the file.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Superblock Checksum</p></td>
- <td>
- <p>The checksum for the superblock.
- </p>
- </td>
+ <tr>
+ <td colspan="2" style="border: dotted;">Indexed Storage Internal
+ Node K<sup>1</sup>
+ </td>
+ <td colspan="2" style="border: dotted;">Reserved (zero)<sup>1</sup></td>
</tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4"><br />Base Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Address of File Free space Info<sup>O</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />End of File Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Driver Information Block Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Root Group Symbol Table Entry</td>
+ </tr>
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets.&rdquo;)</td>
+ </tr>
+ <tr>
+ <td>&nbsp;</td>
+ <td>(Items marked with a &lsquo;1&rsquo; in the above table are
+ new in version 1 of the superblock)</td>
+ </tr>
+ </table>
+</div>
<br />
-<h3><a name="DriverInfo">
-II.B. Disk Format: Level 0B - File Driver Info</a></h3>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Format Signature</p></td>
+ <td><p>This field contains a constant value and can be used
+ to quickly identify a file as being an HDF5 file. The constant
+ value is designed to allow easy identification of an HDF5 file and
+ to allow certain types of data corruption to be detected. The file
+ signature of an HDF5 file always contains the following values:</p>
+ <center>
+ <table border align="center" cellpadding="4">
+ <tr align="center">
+ <td align="right">Decimal:</td>
+ <td width="8%">137</td>
+ <td width="8%">72</td>
+ <td width="8%">68</td>
+ <td width="8%">70</td>
+ <td width="8%">13</td>
+ <td width="8%">10</td>
+ <td width="8%">26</td>
+ <td width="8%">10</td>
+ </tr>
+
+ <tr align="center">
+ <td align="right">Hexadecimal:</td>
+ <td>89</td>
+ <td>48</td>
+ <td>44</td>
+ <td>46</td>
+ <td>0d</td>
+ <td>0a</td>
+ <td>1a</td>
+ <td>0a</td>
+ </tr>
- <p>The <b>driver information block</b> is an optional region of the
- file which contains information needed by the file driver
- to reopen a file. The format is described below:</p>
+ <tr align="center">
+ <td align="right">ASCII C Notation:</td>
+ <td>\211</td>
+ <td>H</td>
+ <td>D</td>
+ <td>F</td>
+ <td>\r</td>
+ <td>\n</td>
+ <td>\032</td>
+ <td>\n</td>
+ </tr>
+ </table>
+ </center>
+ <p>
+ This signature both identifies the file as an HDF5 file and
+ provides for immediate detection of common file-transfer problems.
+ The first two bytes distinguish HDF5 files on systems that expect
+ the first two bytes to identify the file type uniquely. The first
+ byte is chosen as a non-ASCII value to reduce the probability that
+ a text file may be misrecognized as an HDF5 file; also, it catches
+ bad file transfers that clear bit 7. Bytes two through four name
+ the format. The CR-LF sequence catches bad file transfers that
+ alter newline sequences. The control-Z character stops file display
+ under MS-DOS. The final line feed checks for the inverse of the
+ CR-LF translation problem. (This is a direct descendent of the <a
+ href="http://www.libpng.org/pub/png/spec/iso/index-object.html#5PNG-file-signature">PNG</a>
+ file signature.)
+ </p>
+ <p>
+ <em>This field is present in version 0+ of the superblock.</em>
+ </p></td>
+ </tr>
+ <tr>
+ <td><p>Version Number of the Superblock</p></td>
+ <td><p>This value is used to determine the format of the
+ information in the superblock. When the format of the information
+ in the superblock is changed, the version number is incremented to
+ the next integer and can be used to determine how the information
+ in the superblock is formatted.</p>
- <div align="center">
- <table class="format">
- <caption>
- Driver Information Block
- </caption>
+ <p>Values of 0, 1 and 2 are defined for this field. (The format
+ of version 2 is described below, not here)</p>
+
+ <p>
+ <em>This field is present in version 0+ of the superblock.</em>
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Version Number of the File&rsquo;s Free Space
+ Information</p></td>
+ <td>
+ <p>This value is used to determine the format of the
+ file&rsquo;s free space information.</p>
+ <p>
+ The only value currently valid in this field is &lsquo;0&rsquo;,
+ which indicates that the file&rsquo;s free space is as described <a
+ href="#FreeSpaceManager">below</a>.
+ </p>
+
+ <p>
+ <em>This field is present in version 0 and 1 of the
+ superblock.</em>
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Version Number of the Root Group Symbol Table Entry</p></td>
+ <td><p>This value is used to determine the format of the
+ information in the Root Group Symbol Table Entry. When the format
+ of the information in that field is changed, the version number is
+ incremented to the next integer and can be used to determine how
+ the information in the field is formatted.</p>
+ <p>
+ The only value currently valid in this field is &lsquo;0&rsquo;,
+ which indicates that the root group symbol table entry is formatted
+ as described <a href="#SymbolTableEntry">below</a>.
+ </p>
+ <p>
+ <em>This field is present in version 0 and 1 of the
+ superblock.</em>
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Version Number of the Shared Header Message Format</p></td>
+ <td><p>This value is used to determine the format of the
+ information in a shared object header message. Since the format of
+ the shared header messages differs from the other private header
+ messages, a version number is used to identify changes in the
+ format.</p>
+ <p>
+ The only value currently valid in this field is &lsquo;0&rsquo;,
+ which indicates that shared header messages are formatted as
+ described <a href="#ObjectHeaderMessages">below</a>.
+ </p>
+
+ <p>
+ <em>This field is present in version 0 and 1 of the
+ superblock.</em>
+ </p></td>
+ </tr>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
+ <td><p>Size of Offsets</p></td>
+ <td><p>This value contains the number of bytes used to store
+ addresses in the file. The values for the addresses of objects in
+ the file are offsets relative to a base address, usually the
+ address of the superblock signature. This allows a wrapper to be
+ added after the file is created without invalidating the internal
+ offset locations.</p>
+
+ <p>
+ <em>This field is present in version 0+ of the superblock.</em>
+ </p></td>
+ </tr>
<tr>
- <td>Version</td>
- <td colspan="3">Reserved</td>
+ <td><p>Size of Lengths</p></td>
+ <td><p>This value contains the number of bytes used to store
+ the size of an object.</p>
+ <p>
+ <em>This field is present in version 0+ of the superblock.</em>
+ </p></td>
</tr>
<tr>
- <td colspan="4">Driver Information Size</td>
+ <td><p>Group Leaf Node K</p></td>
+ <td>
+ <p>Each leaf node of a group B-tree will have at least this many
+ entries but not more than twice this many. If a group has a single
+ leaf node then it may have fewer entries.</p>
+ <p>This value must be greater than zero.</p>
+ <p>
+ See the <a href="#Btrees">description</a> of B-trees below.
+ </p>
+
+ <p>
+ <em>This field is present in version 0 and 1 of the
+ superblock.</em>
+ </p>
+ </td>
</tr>
<tr>
- <td colspan="4"><br />Driver Identification (8 bytes)<br /><br /></td>
+ <td><p>Group Internal Node K</p></td>
+ <td>
+ <p>Each internal node of a group B-tree will have at least this
+ many entries but not more than twice this many. If the group has
+ only one internal node then it might have fewer entries.</p>
+ <p>This value must be greater than zero.</p>
+ <p>
+ See the <a href="#Btrees">description</a> of B-trees below.
+ </p>
+
+ <p>
+ <em>This field is present in version 0 and 1 of the
+ superblock.</em>
+ </p>
+ </td>
</tr>
<tr>
- <td colspan="4"><br /><br />Driver Information (<em>variable size</em>)<br /><br /><br /></td>
+ <td><p>File Consistency Flags</p></td>
+ <td>
+ <p>This value contains flags to indicate information about the
+ consistency of the information contained within the file.
+ Currently, the following bit flags are defined:</p>
+ <ul>
+ <li>Bit 0 set indicates that the file is opened for
+ write-access.</li>
+ <li>Bit 1 set indicates that the file has been verified for
+ consistency and is guaranteed to be consistent with the format
+ defined in this document.</li>
+ <li>Bits 2-31 are reserved for future use.</li>
+ </ul> Bit 0 should be set as the first action when a file is opened for
+ write access and should be cleared only as the final action when
+ closing a file. Bit 1 should be cleared during normal access to a
+ file and only set after the file&rsquo;s consistency is guaranteed
+ by the library or a consistency utility.
+ <p></p>
+
+ <p>
+ <em>This field is present in version 0+ of the superblock.</em>
+ </p>
+ </td>
</tr>
- </table>
- </div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <tr>
+ <td><p>Indexed Storage Internal Node K</p></td>
+ <td>
+ <p>Each internal node of an indexed storage B-tree will have at
+ least this many entries but not more than twice this many. If the
+ index storage B-tree has only one internal node then it might have
+ fewer entries.</p>
+ <p>This value must be greater than zero.</p>
+ <p>
+ See the <a href="#Btrees">description</a> of B-trees below.
+ </p>
+
+ <p>
+ <em>This field is present in version 1 of the superblock.</em>
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Base Address</p></td>
+ <td>
+ <p>This is the absolute file address of the first byte of the
+ HDF5 data within the file. The library currently constrains this
+ value to be the absolute file address of the superblock itself when
+ creating new files; future versions of the library may provide
+ greater flexibility. When opening an existing file and this address
+ does not match the offset of the superblock, the library assumes
+ that the entire contents of the HDF5 file have been adjusted in the
+ file and adjusts the base address and end of file address to
+ reflect their new positions in the file. Unless otherwise noted,
+ all other file addresses are relative to this base address.</p>
+
+ <p>
+ <em>This field is present in version 0+ of the superblock.</em>
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Address of Global Free-space Index</p></td>
+ <td>
+ <p>
+ The file&rsquo;s free space is not persistent for version 0 and 1
+ of the superblock. Currently this field always contains the <a
+ href="#UndefinedAddress">undefined address</a>.
+ </p>
+
+ <p>
+ <em>This field is present in version 0 and 1 of the
+ superblock.</em>
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>End of File Address</p></td>
+ <td>
+ <p>This is the absolute file address of the first byte past the
+ end of all HDF5 data. It is used to determine whether a file has
+ been accidentally truncated and as an address where file data
+ allocation can occur if space from the free list is not used.</p>
+
+ <p>
+ <em>This field is present in version 0+ of the superblock.</em>
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Driver Information Block Address</p></td>
+ <td>
+ <p>
+ This is the relative file address of the file driver information
+ block which contains driver-specific information needed to reopen
+ the file. If there is no driver information block then this entry
+ should be the <a href="#UndefinedAddress">undefined address</a>.
+ </p>
+
+ <p>
+ <em>This field is present in version 0 and 1 of the
+ superblock.</em>
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Root Group Symbol Table Entry</p></td>
+ <td>
+ <p>
+ This is the <a href="#SymbolTableEntry">symbol table entry</a> of
+ the root group, which serves as the entry point into the group
+ graph for the file.
+ </p>
+
+ <p>
+ <em>This field is present in version 0 and 1 of the
+ superblock.</em>
+ </p>
+ </td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<p>Version 2 of the superblock is described below:</p>
+
+<div align="center">
+ <table class="format">
+ <caption>Superblock (Version 2)</caption>
+
+ <tr>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td><p>Version</p></td>
- <td>
- <p>The version number of the Driver Information Block.
- This document describes version 0.
- </p>
- </td>
+ <td colspan="4"><br />Format Signature (8 bytes)<br />
+ <br /></td>
</tr>
<tr>
- <td><p>Driver Information Size</p></td>
- <td>
- <p>The size in bytes of the <em>Driver Information</em> field.
- </p>
- </td>
+ <td>Version # of Superblock</td>
+ <td>Size of Offsets</td>
+ <td>Size of Lengths</td>
+ <td>File Consistency Flags</td>
</tr>
<tr>
- <td><p>Driver Identification</p></td>
- <td>
- <p>This is an eight-byte ASCII string without null
- termination which identifies the driver and/or version number
- of the Driver Information Block. The predefined driver encoded
- in this field by the HDF5 Library is identified by the
- letters <code>NCSA</code> followed by the first four characters of
- the driver name. If the Driver Information block is not
- the original version then the last letter(s) of the
- identification will be replaced by a version number in
- ASCII, starting with 0.
- </p>
- <p>
- Identification for user-defined drivers is also eight-byte long.
- It can be arbitrary but should be unique to avoid
- the four character prefix &ldquo;NCSA&rdquo;.
- </p>
- </td>
+ <td colspan="4"><br />Base Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Superblock Extension Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />End of File Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Root Group Object Header Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Superblock Checksum</td>
+ </tr>
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets.&rdquo;)</td>
+ </tr>
+ </table>
+
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Format Signature</p></td>
+ <td>
+ <p>This field is the same as described for versions 0 and 1 of
+ the superblock.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Version Number of the Superblock</p></td>
+ <td>
+ <p>This field has a value of 2 and has the same meaning as for
+ versions 0 and 1.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Size of Offsets</p></td>
+ <td>
+ <p>This field is the same as described for versions 0 and 1 of
+ the superblock.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Size of Lengths</p></td>
+ <td>
+ <p>This field is the same as described for versions 0 and 1 of
+ the superblock.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>File Consistency Flags</p></td>
+ <td>
+ <p>This field is the same as described for versions 0 and 1
+ except that it is smaller (the number of reserved bits has been
+ reduced from 30 to 6).</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Base Address</p></td>
+ <td>
+ <p>This field is the same as described for versions 0 and 1 of
+ the superblock.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Superblock Extension Address</p></td>
+ <td>
+ <p>
+ The field is the address of the object header for the <a
+ href="#SuperblockExt">superblock extension</a>. If there is no
+ extension then this entry should be the <a href="#UndefinedAddress">undefined
+ address</a>.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>End of File Address</p></td>
+ <td>
+ <p>This field is the same as described for versions 0 and 1 of
+ the superblock.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Root Group Object Header Address</p></td>
+ <td>
+ <p>
+ This is the address of the <a href="#DataObject">root group
+ object header</a>, which serves as the entry point into the group
+ graph for the file.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Superblock Checksum</p></td>
+ <td>
+ <p>The checksum for the superblock.</p>
+ </td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<h3>
+ <a name="DriverInfo"> II.B. Disk Format: Level 0B - File Driver
+ Info</a>
+</h3>
+
+<p>
+ The <b>driver information block</b> is an optional region of the file
+ which contains information needed by the file driver to reopen a file.
+ The format is described below:
+</p>
+
+
+<div align="center">
+ <table class="format">
+ <caption>Driver Information Block</caption>
+
+ <tr>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td colspan="3">Reserved</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Driver Information Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Driver Identification (8 bytes)<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />
+ <br />Driver Information (<em>variable size</em>)<br />
+ <br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>The version number of the Driver Information Block. This
+ document describes version 0.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Driver Information Size</p></td>
+ <td>
+ <p>
+ The size in bytes of the <em>Driver Information</em> field.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Driver Identification</p></td>
+ <td>
+ <p>
+ This is an eight-byte ASCII string without null termination which
+ identifies the driver and/or version number of the Driver
+ Information Block. The predefined driver encoded in this field by
+ the HDF5 Library is identified by the letters
+ <code>NCSA</code>
+ followed by the first four characters of the driver name. If the
+ Driver Information block is not the original version then the last
+ letter(s) of the identification will be replaced by a version
+ number in ASCII, starting with 0.
+ </p>
+ <p>Identification for user-defined drivers is also eight-byte
+ long. It can be arbitrary but should be unique to avoid the four
+ character prefix &ldquo;NCSA&rdquo;.</p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Driver Information</p></td>
- <td>Driver information is stored in a format defined by the
- file driver (see description below).</td>
+ <td><p>Driver Information</p></td>
+ <td>Driver information is stored in a format defined by the file
+ driver (see description below).</td>
</tr>
- </table>
- </div>
+ </table>
+</div>
+
+<br /> The two drivers encoded in the
+<em>Driver Identification</em> field are as follows:
+<ul>
+ <li>Multi driver:
+ <p>The identifier for this driver is &ldquo;NCSAmulti&rdquo;. This
+ driver provides a mechanism for segregating raw data and different
+ types of metadata into multiple files. These files are viewed by the
+ library as a single virtual HDF5 file with a single file address. A
+ maximum of 6 files will be created for the following data:
+ superblock, B-tree, raw data, global heap, local heap, and object
+ header. More than one type of data can be written to the same file.</p>
+ </li>
+ <li>Family driver
+ <p>The identifier for this driver is &ldquo;NCSAfami&rdquo; and is
+ encoded in this field for library version 1.8 and after. This driver
+ is designed for systems that do not support files larger than 2
+ gigabytes by splitting the HDF5 file address space across several
+ smaller files. It does nothing to segregate metadata and raw data;
+ they are mixed in the address space just as they would be in a single
+ contiguous file.</p>
+ </li>
+</ul>
+<p>
+ The format of the <em>Driver Information</em> field for the above two
+ drivers are described below:
+</p>
- <br />
- The two drivers encoded in the <em>Driver Identification</em> field are as follows:
- <ul>
- <li>
- Multi driver:
- <p>
- The identifier for this driver is &ldquo;NCSAmulti&rdquo;.
- This driver provides a mechanism for segregating raw data and different types of metadata
- into multiple files.
- These files are viewed by the library as a single virtual HDF5 file with a single file address.
- A maximum of 6 files will be created for the following data:
- superblock, B-tree, raw data, global heap, local heap, and object header.
- More than one type of data can be written to the same file.
- </p></li>
- <li>
- Family driver
- <p>
- The identifier for this driver is &ldquo;NCSAfami&rdquo; and is encoded in this field for library version 1.8 and after.
- This driver is designed for systems that do not support files larger than 2 gigabytes
- by splitting the HDF5 file address space across several smaller files.
- It does nothing to segregate metadata and raw data;
- they are mixed in the address space just as they would be in a single contiguous file.
- </p></li>
- </ul>
- <p>The format of the <em>Driver Information</em> field for the
- above two drivers are described below:</p>
-
- <div align="center">
- <table class="format">
- <caption>
- Multi Driver Information
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Member Mapping</td>
- <td>Member Mapping</td>
- <td>Member Mapping</td>
- <td>Member Mapping</td>
- </tr>
-
- <tr>
- <td>Member Mapping</td>
- <td>Member Mapping</td>
- <td>Reserved</td>
- <td>Reserved</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Address of Member File 1<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />End of Address for Member File 1<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Address of Member File 2<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />End of Address for Member File 2<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />... ...<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Address of Member File N<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />End of Address for Member File N<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Name of Member File 1 <em>(variable size)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Name of Member File 2 <em>(variable size)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />... ...<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Name of Member File N <em>(variable size)</em><br /><br /></td>
- </tr>
+<div align="center">
+ <table class="format">
+ <caption>Multi Driver Information</caption>
- </table>
- </div>
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
+ <tr>
+ <td>Member Mapping</td>
+ <td>Member Mapping</td>
+ <td>Member Mapping</td>
+ <td>Member Mapping</td>
+ </tr>
+
+ <tr>
+ <td>Member Mapping</td>
+ <td>Member Mapping</td>
+ <td>Reserved</td>
+ <td>Reserved</td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Address of Member File 1<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />End of Address for Member File 1<br />
+ <br /></td>
+ </tr>
- <tr>
- <td><p>Member Mapping</p></td>
- <td><p>These fields are integer values from 1 to 6
- indicating how the data can be mapped to or merged with another type of
- data.
- <table class="list">
+ <tr>
+ <td colspan="4"><br />Address of Member File 2<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />End of Address for Member File 2<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />... ...<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Address of Member File N<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />End of Address for Member File N<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Name of Member File 1 <em>(variable
+ size)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Name of Member File 2 <em>(variable
+ size)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />... ...<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Name of Member File N <em>(variable
+ size)</em><br />
+ <br /></td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Member Mapping</p></td>
+ <td><p>These fields are integer values from 1 to 6
+ indicating how the data can be mapped to or merged with another
+ type of data.</p>
+ <table class="list">
<tr>
- <th width="20%" align="center">Member Mapping</th>
- <th width="80%" align="left">Description</th>
+ <th width="20%" align="center">Member Mapping</th>
+ <th width="80%" align="left">Description</th>
</tr>
<tr>
<td align="center">1</td>
@@ -1261,4097 +1399,4089 @@ II.B. Disk Format: Level 0B - File Driver Info</a></h3>
<td align="center">6</td>
<td>The object header data.</td>
</tr>
- </table></p>
- <p>For example, if the third field has the value 3 and all the rest have the
- value 1, it means there are two files: one for raw data, and one for superblock,
- B-tree, global heap, local heap, and object header.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Reserved</p></td>
- <td><p>These fields are reserved and should always be zero.</p></td>
- </tr>
-
- <tr>
- <td><p>Address of Member File N</p></td>
- <td><p>This field Specifies the virtual address at which the member file starts.</p>
- <p>N is the number of member files.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>End of Address for Member File N</p></td>
- <td><p>This field is the end of the allocated address for the member file.
- </p></td>
- </tr>
-
- <tr>
- <td><p>Name of Member File N</p></td>
- <td><p>This field is the null-terminated name of the member file and
- its length should be multiples of 8 bytes.
- Additional bytes will be padded with <em>NULL</em>s. The default naming
- convention is <em>%s-X.h5</em>, where <em>X</em> is one of the letters
- <em>s</em> (for superblock), <em>b</em> (for B-tree), <em>r</em> (for raw data),
- <em>g</em> (for global heap), <em>l</em> (for local heap), and <em>o</em> (for
- object header). The name of the whole HDF5 file will substitute the <em>%s</em>
- in the string.
- </p>
- </td>
- </tr>
- </table>
- </div>
+ </table>
+ <p></p>
+ <p>For example, if the third field has the value 3 and all the
+ rest have the value 1, it means there are two files: one for raw
+ data, and one for superblock, B-tree, global heap, local heap, and
+ object header.</p></td>
+ </tr>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Family Driver Information
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td colspan="8"><br />Size of Member File<br /><br /></td>
- </tr>
+ <tr>
+ <td><p>Reserved</p></td>
+ <td><p>These fields are reserved and should always be zero.</p></td>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td><p>Address of Member File N</p></td>
+ <td><p>This field Specifies the virtual address at which the
+ member file starts.</p>
+ <p>N is the number of member files.</p></td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Size of Member File</p></td>
- <td><p>This field is the size of the member file in the family of files.</p></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td><p>End of Address for Member File N</p></td>
+ <td><p>This field is the end of the allocated address for
+ the member file.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Name of Member File N</p></td>
+ <td><p>
+ This field is the null-terminated name of the member file and its
+ length should be multiples of 8 bytes. Additional bytes will be
+ padded with <em>NULL</em>s. The default naming convention is <em>%s-X.h5</em>,
+ where <em>X</em> is one of the letters <em>s</em> (for superblock),
+ <em>b</em> (for B-tree), <em>r</em> (for raw data), <em>g</em> (for
+ global heap), <em>l</em> (for local heap), and <em>o</em> (for
+ object header). The name of the whole HDF5 file will substitute the
+ <em>%s</em> in the string.
+ </p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Family Driver Information</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="8"><br />Size of Member File<br />
+ <br /></td>
+ </tr>
+
+ </table>
+</div>
<br />
-<h3><a name="SuperblockExt">
-II.C. Disk Format: Level 0C - Superblock Extension</a></h3>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Size of Member File</p></td>
+ <td><p>This field is the size of the member file in the
+ family of files.</p></td>
+ </tr>
+ </table>
+</div>
- <p>The <em>superblock extension</em> is used to store superblock metadata
- which is either optional, or added after the version of the superblock
- was defined. Superblock extensions may only exist when version 2+ of
- superblock is used. A superblock extension is an object header which may
- hold the following messages:</p>
- <ul>
- <li>
- <a href="#SOHMTableMessage">Shared Message Table message</a> containing
- information to locate the master table of shared object header message
- indices.</li>
- <li>
- <a href="#BtreeKValuesMessage">B-tree &lsquo;K&rsquo; Values message</a> containing
- non-default B-tree &lsquo;K&rsquo; values.</li>
- <li>
- <a href="#DrvInfoMessage">Driver Info message</a> containing information
- needed by the file driver in order to reopen a file.
- See also the
- <a href="#DriverInfo">&ldquo;Disk Format: Level 0B - File Driver
- Info&rdquo;</a> section above.</li>
- <li>
- <a href="#FsinfoMessage">File Space Info message</a> containing
- information about file space handling in the file.</li>
- </ul>
+<br />
+<h3>
+ <a name="SuperblockExt"> II.C. Disk Format: Level 0C - Superblock
+ Extension</a>
+</h3>
+
+<p>
+ The <em>superblock extension</em> is used to store superblock metadata
+ which is either optional, or added after the version of the superblock
+ was defined. Superblock extensions may only exist when version 2+ of
+ superblock is used. A superblock extension is an object header which
+ may hold the following messages:
+</p>
+<ul>
+ <li><a href="#SOHMTableMessage">Shared Message Table message</a>
+ containing information to locate the master table of shared object
+ header message indices.</li>
+ <li><a href="#BtreeKValuesMessage">B-tree &lsquo;K&rsquo;
+ Values message</a> containing non-default B-tree &lsquo;K&rsquo; values.</li>
+ <li><a href="#DrvInfoMessage">Driver Info message</a> containing
+ information needed by the file driver in order to reopen a file. See
+ also the <a href="#DriverInfo">&ldquo;Disk Format: Level 0B - File
+ Driver Info&rdquo;</a> section above.</li>
+ <li><a href="#FsinfoMessage">File Space Info message</a>
+ containing information about file space handling in the file.</li>
+</ul>
<br />
<br />
<hr />
-<h2><a name="FileInfra">
-III. Disk Format: Level 1 - File Infrastructure</a></h2>
-
-<br />
-<h3><a name="Btrees">
-III.A. Disk Format: Level 1A - B-trees and B-tree Nodes</a></h3>
-
- <p>B-trees allow flexible storage for objects which tend to grow
- in ways that cause the object to be stored discontiguously. B-trees
- are described in various algorithms books including &ldquo;Introduction to
- Algorithms&rdquo; by Thomas H. Cormen, Charles E. Leiserson, and Ronald
- L. Rivest. B-trees are used in several places in the HDF5 file format,
- when an index is needed for another data structure.</p>
-
- <p>The version 1 B-tree structure described below is the original index
- structure, but are limited by some bugs in our implementation (mainly in
- how they handle deleting records). The version 1 B-trees are being phased
- out in favor of the version 2 B-trees described below, although both
- types of structures may be found in the same file, depending on
- application settings when creating the file.</p>
-
-<br />
-<h4><a name="V1Btrees">
-III.A.1. Disk Format: Level 1A1 - Version 1 B-trees (B-link Trees)</a></h4>
-
- <p>Version 1 B-trees in HDF5 files an implementation of the B-link tree,
- in which the sibling nodes at a particular level in the tree are stored
- in a doubly-linked list, is described in the &ldquo;Efficient Locking for
- Concurrent Operations on B-trees&rdquo; paper by Phillip Lehman and S. Bing Yao
- as published in the <cite>ACM Transactions on Database Systems</cite>,
- Vol. 6, No. 4, December 1981.</p>
-
- <p>The B-link trees implemented by the file format contain one more
- key than the number of children. In other words, each child
- pointer out of a B-tree node has a left key and a right key.
- The pointers out of internal nodes point to sub-trees while
- the pointers out of leaf nodes point to symbol nodes and
- raw data chunks.
- Aside from that difference, internal nodes and leaf nodes
- are identical.</p>
-
- <div align="center">
- <table class="format">
- <caption>
- B-link Tree Nodes
- </caption>
+<h2>
+ <a name="FileInfra"> III. Disk Format: Level 1 - File
+ Infrastructure</a>
+</h2>
+
+<br />
+<h3>
+ <a name="Btrees"> III.A. Disk Format: Level 1A - B-trees and B-tree
+ Nodes</a>
+</h3>
+
+<p>B-trees allow flexible storage for objects which tend to grow in
+ ways that cause the object to be stored discontiguously. B-trees are
+ described in various algorithms books including &ldquo;Introduction to
+ Algorithms&rdquo; by Thomas H. Cormen, Charles E. Leiserson, and Ronald
+ L. Rivest. B-trees are used in several places in the HDF5 file format,
+ when an index is needed for another data structure.</p>
+
+<p>The version 1 B-tree structure described below is the original
+ index structure, but are limited by some bugs in our implementation
+ (mainly in how they handle deleting records). The version 1 B-trees are
+ being phased out in favor of the version 2 B-trees described below,
+ although both types of structures may be found in the same file,
+ depending on application settings when creating the file.</p>
+
+<br />
+<h4>
+ <a name="V1Btrees"> III.A.1. Disk Format: Level 1A1 - Version 1
+ B-trees (B-link Trees)</a>
+</h4>
+
+<p>
+ Version 1 B-trees in HDF5 files an implementation of the B-link tree,
+ in which the sibling nodes at a particular level in the tree are stored
+ in a doubly-linked list, is described in the &ldquo;Efficient Locking
+ for Concurrent Operations on B-trees&rdquo; paper by Phillip Lehman and
+ S. Bing Yao as published in the <cite>ACM Transactions on
+ Database Systems</cite>, Vol. 6, No. 4, December 1981.
+</p>
+
+<p>The B-link trees implemented by the file format contain one more
+ key than the number of children. In other words, each child pointer out
+ of a B-tree node has a left key and a right key. The pointers out of
+ internal nodes point to sub-trees while the pointers out of leaf nodes
+ point to symbol nodes and raw data chunks. Aside from that difference,
+ internal nodes and leaf nodes are identical.</p>
+
+<div align="center">
+ <table class="format">
+ <caption>B-link Tree Nodes</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td colspan="4">Signature</td>
</tr>
<tr>
- <td>Node Type</td>
- <td>Node Level</td>
- <td colspan="2">Entries Used</td>
+ <td>Node Type</td>
+ <td>Node Level</td>
+ <td colspan="2">Entries Used</td>
</tr>
<tr>
- <td colspan="4"><br />Address of Left Sibling<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Address of Left Sibling<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Address of Right Sibling<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Address of Right Sibling<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4">Key 0 (variable size)</td>
+ <td colspan="4">Key 0 (variable size)</td>
</tr>
<tr>
- <td colspan="4"><br />Address of Child 0<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Address of Child 0<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4">Key 1 (variable size)</td>
+ <td colspan="4">Key 1 (variable size)</td>
</tr>
<tr>
- <td colspan="4"><br />Address of Child 1<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Address of Child 1<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4">...</td>
+ <td colspan="4">...</td>
</tr>
<tr>
- <td colspan="4">Key 2<em>K</em> (variable size)</td>
+ <td colspan="4">Key 2<em>K</em> (variable size)
+ </td>
</tr>
<tr>
- <td colspan="4"><br />Address of Child 2<em>K</em><sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Address of Child 2<em>K</em><sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4">Key 2<em>K</em>+1 (variable size)</td>
+ <td colspan="4">Key 2<em>K</em>+1 (variable size)
+ </td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>TREE</code>&rdquo; is
- used to indicate the
- beginning of a B-link tree node. This gives file
- consistency checking utilities a better chance of
- reconstructing a damaged file.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Node Type</p></td>
- <td>
- <p>Each B-link tree points to a particular type of data.
- This field indicates the type of data as well as
- implying the maximum degree <em>K</em> of the tree and
- the size of each Key field.
-
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Node Type</th>
- <th width="80%" align="left">Description</th>
- </tr>
- <tr>
- <td align="center">0</td>
- <td>This tree points to group nodes.</td>
- </tr>
- <tr>
- <td align="center">1</td>
- <td>This tree points to raw data chunk nodes.</td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Node Level</p></td>
- <td>
- <p>The node level indicates the level at which this node
- appears in the tree (leaf nodes are at level zero). Not
- only does the level indicate whether child pointers
- point to sub-trees or to data, but it can also be used
- to help file consistency checking utilities reconstruct
- damaged trees.
- </p>
- </td>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>TREE</code>
+ &rdquo; is used to indicate the beginning of a B-link tree node.
+ This gives file consistency checking utilities a better chance of
+ reconstructing a damaged file.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Node Type</p></td>
+ <td>
+ <p>
+ Each B-link tree points to a particular type of data. This field
+ indicates the type of data as well as implying the maximum degree <em>K</em>
+ of the tree and the size of each Key field.
+
+
+ </p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Node Type</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+ <tr>
+ <td align="center">0</td>
+ <td>This tree points to group nodes.</td>
+ </tr>
+ <tr>
+ <td align="center">1</td>
+ <td>This tree points to raw data chunk nodes.</td>
+ </tr>
+ </table>
+ <p></p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Node Level</p></td>
+ <td>
+ <p>The node level indicates the level at which this node appears
+ in the tree (leaf nodes are at level zero). Not only does the level
+ indicate whether child pointers point to sub-trees or to data, but
+ it can also be used to help file consistency checking utilities
+ reconstruct damaged trees.</p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Entries Used</p></td>
- <td>
- <p>This determines the number of children to which this
- node points. All nodes of a particular type of tree
- have the same maximum degree, but most nodes will point
- to less than that number of children. The valid child
- pointers and keys appear at the beginning of the node
- and the unused pointers and keys appear at the end of
- the node. The unused pointers and keys have undefined
- values.
- </p>
- </td>
+ <td><p>Entries Used</p></td>
+ <td>
+ <p>This determines the number of children to which this node
+ points. All nodes of a particular type of tree have the same
+ maximum degree, but most nodes will point to less than that number
+ of children. The valid child pointers and keys appear at the
+ beginning of the node and the unused pointers and keys appear at
+ the end of the node. The unused pointers and keys have undefined
+ values.</p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Address of Left Sibling</p></td>
- <td>
- <p>This is the relative file address of the left sibling of
- the current node. If the current
- node is the left-most node at this level then this field
- is the <a href="#UndefinedAddress">undefined address</a>.
- </p>
- </td>
+ <td><p>Address of Left Sibling</p></td>
+ <td>
+ <p>
+ This is the relative file address of the left sibling of the
+ current node. If the current node is the left-most node at this
+ level then this field is the <a href="#UndefinedAddress">undefined
+ address</a>.
+ </p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Address of Right Sibling</p></td>
- <td>
- <p>This is the relative file address of the right sibling of
- the current node. If the current
- node is the right-most node at this level then this
- field is the <a href="#UndefinedAddress">undefined address</a>.
- </p>
- </td>
+ <td><p>Address of Right Sibling</p></td>
+ <td>
+ <p>
+ This is the relative file address of the right sibling of the
+ current node. If the current node is the right-most node at this
+ level then this field is the <a href="#UndefinedAddress">undefined
+ address</a>.
+ </p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Keys and Child Pointers</p></td>
- <td>
- <p>Each tree has 2<em>K</em>+1 keys with 2<em>K</em>
- child pointers interleaved between the keys. The number
- of keys and child pointers actually containing valid
- values is determined by the node&rsquo;s <em>Entries Used</em> field.
- If that field is <em>N</em> then the B-link tree contains
- <em>N</em> child pointers and <em>N</em>+1 keys.
- </p>
- </td>
+ <td><p>Keys and Child Pointers</p></td>
+ <td>
+ <p>
+ Each tree has 2<em>K</em>+1 keys with 2<em>K</em> child pointers
+ interleaved between the keys. The number of keys and child pointers
+ actually containing valid values is determined by the node&rsquo;s
+ <em>Entries Used</em> field. If that field is <em>N</em> then the
+ B-link tree contains <em>N</em> child pointers and <em>N</em>+1
+ keys.
+ </p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Key</p></td>
- <td>
- <p>The format and size of the key values is determined by
- the type of data to which this tree points. The keys are
- ordered and are boundaries for the contents of the child
- pointer; that is, the key values represented by child
- <em>N</em> fall between Key <em>N</em> and Key
- <em>N</em>+1. Whether the interval is open or closed on
- each end is determined by the type of data to which the
- tree points.
- </p>
-
- <p>
- The format of the key depends on the node type.
- For nodes of node type 0 (group nodes), the key is formatted as
- follows:
-
- <table class="list">
- <tr>
- <td width="20%">A single field of <i>Size of Lengths</i>
- bytes:</td>
- <td width="80%">Indicates the byte offset into the local heap
- for the first object name in the subtree which
- that key describes.
- </td>
- </tr>
- </table>
- </p>
-
-
- <p>
- For nodes of node type 1 (chunked raw data nodes), the key is
- formatted as follows:
-
- <table class="list">
- <tr>
- <td width="20%">Bytes 1-4:</td>
- <td width="80%">Size of chunk in bytes.</td>
- </tr>
- <tr>
- <td>Bytes 4-8:</td>
- <td>Filter mask, a 32-bit bit field indicating which
- filters have been skipped for this chunk. Each filter
- has an index number in the pipeline (starting at 0, with
- the first filter to apply) and if that filter is skipped,
- the bit corresponding to its index is set.</td>
- </tr>
- <tr>
- <td>(<em>D + 1</em>) 64-bit fields:</td>
- <td>The offset of the
- chunk within the dataset where <i>D</i> is the number
- of dimensions of the dataset, and the last value is the
- offset within the dataset&rsquo;s datatype and should always be
- zero. For example, if
- a chunk in a 3-dimensional dataset begins at the
- position <code>[5,5,5]</code>, there will be three
- such 64-bit values, each with the value of
- <code>5</code>, followed by a <code>0</code> value.</td>
- </tr>
- </table>
- </p>
-
- </td>
+ <td><p>Key</p></td>
+ <td>
+ <p>
+ The format and size of the key values is determined by the type of
+ data to which this tree points. The keys are ordered and are
+ boundaries for the contents of the child pointer; that is, the key
+ values represented by child <em>N</em> fall between Key <em>N</em>
+ and Key <em>N</em>+1. Whether the interval is open or closed on
+ each end is determined by the type of data to which the tree
+ points.
+ </p>
+
+ <p>The format of the key depends on the node type. For nodes of
+ node type 0 (group nodes), the key is formatted as follows:</p>
+ <table class="list">
+ <tr>
+ <td width="20%">A single field of <i>Size of Lengths</i>
+ bytes:
+ </td>
+ <td width="80%">Indicates the byte offset into the local heap
+ for the first object name in the subtree which that key
+ describes.</td>
+ </tr>
+ </table>
+ <p></p>
+
+
+ <p>For nodes of node type 1 (chunked raw data nodes), the key is
+ formatted as follows:</p>
+ <table class="list">
+ <tr>
+ <td width="20%">Bytes 1-4:</td>
+ <td width="80%">Size of chunk in bytes.</td>
+ </tr>
+ <tr>
+ <td>Bytes 4-8:</td>
+ <td>Filter mask, a 32-bit bit field indicating which filters
+ have been skipped for this chunk. Each filter has an index number
+ in the pipeline (starting at 0, with the first filter to apply)
+ and if that filter is skipped, the bit corresponding to its index
+ is set.</td>
+ </tr>
+ <tr>
+ <td>(<em>D + 1</em>) 64-bit fields:
+ </td>
+ <td>The offset of the chunk within the dataset where <i>D</i>
+ is the number of dimensions of the dataset, and the last value is
+ the offset within the dataset&rsquo;s datatype and should always
+ be zero. For example, if a chunk in a 3-dimensional dataset
+ begins at the position <code>[5,5,5]</code>, there will be three
+ such 64-bit values, each with the value of <code>5</code>,
+ followed by a <code>0</code> value.
+ </td>
+ </tr>
+ </table>
+ <p></p>
+
+ </td>
</tr>
<tr valign="top">
- <td><p>Child Pointer</p></td>
- <td>
- <p>The tree node contains file addresses of subtrees or
- data depending on the node level. Nodes at Level 0 point
- to data addresses, either raw data chunks or group nodes.
- Nodes at non-zero levels point to other nodes of the
- same B-tree.
- </p>
- <p>For raw data chunk nodes, the child pointer is the address
- of a single raw data chunk. For group nodes, the child pointer
- points to a <a href="#SymbolTable">symbol table</a>, which contains
- information for multiple symbol table entries.
- </p>
- </td>
+ <td><p>Child Pointer</p></td>
+ <td>
+ <p>The tree node contains file addresses of subtrees or data
+ depending on the node level. Nodes at Level 0 point to data
+ addresses, either raw data chunks or group nodes. Nodes at non-zero
+ levels point to other nodes of the same B-tree.</p>
+ <p>
+ For raw data chunk nodes, the child pointer is the address of a
+ single raw data chunk. For group nodes, the child pointer points to
+ a <a href="#SymbolTable">symbol table</a>, which contains
+ information for multiple symbol table entries.
+ </p>
+ </td>
</tr>
- </table>
- </div>
-
- <p>
- Conceptually, each B-tree node looks like this:</p>
- <center>
- <table>
- <tr valign="top" align="center">
- <td>key[0]</td><td>&nbsp;</td>
- <td>child[0]</td><td>&nbsp;</td>
- <td>key[1]</td><td>&nbsp;</td>
- <td>child[1]</td><td>&nbsp;</td>
- <td>key[2]</td><td>&nbsp;</td>
- <td>...</td><td>&nbsp;</td>
- <td>...</td><td>&nbsp;</td>
- <td>key[<i>N</i>-1]</td><td>&nbsp;</td>
- <td>child[<i>N</i>-1]</td><td>&nbsp;</td>
- <td>key[<i>N</i>]</td>
- </tr>
- </table>
- </center>
- <br />
-
- where child[<i>i</i>] is a pointer to a sub-tree (at a level
- above Level 0) or to data (at Level 0).
- Each key[<i>i</i>] describes an <i>item</i> stored by the B-tree
- (a chunk or an object of a group node). The range of values
- represented by child[<i>i</i>] is indicated by key[<i>i</i>]
- and key[<i>i</i>+1].
-
-
- <p>The following question must next be answered:
- &ldquo;Is the value described by key[<i>i</i>] contained in
- child[<i>i</i>-1] or in child[<i>i</i>]?&rdquo;
- The answer depends on the type of tree.
- In trees for groups (node type 0) the object described by
- key[<i>i</i>] is the greatest object contained in
- child[<i>i</i>-1] while in chunk trees (node type 1) the
- chunk described by key[<i>i</i>] is the least chunk in
- child[<i>i</i>].</p>
-
- <p>That means that key[0] for group trees is sometimes unused;
- it points to offset zero in the heap, which is always the
- empty string and compares as &ldquo;less-than&rdquo; any valid object name.</p>
-
- <p>And key[<i>N</i>] for chunk trees is sometimes unused;
- it contains a chunk offset which compares as &ldquo;greater-than&rdquo;
- any other chunk offset and has a chunk byte size of zero
- to indicate that it is not actually allocated.</p>
-
-<br />
-<h4><a name="V2Btrees">
-III.A.2. Disk Format: Level 1A2 - Version 2 B-trees</a></h4>
-
- <p>Version 2 B-trees are &ldquo;traditional&rdquo; B-trees, with one major difference.
- Instead of just using a simple pointer (or address in the file) to a
- child of an internal node, the pointer to the child node contains two
- additional pieces of information: the number of records in the child
- node itself, and the total number of records in the child node and
- all its descendants. Storing this additional information allows fast
- array-like indexing to locate the n<sup>th</sup> record in the B-tree.</p>
-
- <p>The entry into a version 2 B-tree is a header which contains global
- information about the structure of the B-tree. The <em>root node
- address</em>
- field in the header points to the B-tree root node, which is either an
- internal or leaf node, depending on the value in the header&rsquo;s
- <em>depth</em> field. An internal node consists of records plus
- pointers to further leaf or internal nodes in the tree. A leaf node
- consists of solely of records. The format of the records depends on
- the B-tree type (stored in the header).</p>
-
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree Header
- </caption>
+ </table>
+</div>
+
+<p>Conceptually, each B-tree node looks like this:</p>
+<center>
+ <table>
+ <tr valign="top" align="center">
+ <td>key[0]</td>
+ <td>&nbsp;</td>
+ <td>child[0]</td>
+ <td>&nbsp;</td>
+ <td>key[1]</td>
+ <td>&nbsp;</td>
+ <td>child[1]</td>
+ <td>&nbsp;</td>
+ <td>key[2]</td>
+ <td>&nbsp;</td>
+ <td>...</td>
+ <td>&nbsp;</td>
+ <td>...</td>
+ <td>&nbsp;</td>
+ <td>key[<i>N</i>-1]
+ </td>
+ <td>&nbsp;</td>
+ <td>child[<i>N</i>-1]
+ </td>
+ <td>&nbsp;</td>
+ <td>key[<i>N</i>]
+ </td>
+ </tr>
+ </table>
+</center>
+<br /> where child[
+<i>i</i>] is a pointer to a sub-tree (at a level above Level 0) or to
+data (at Level 0). Each key[
+<i>i</i>] describes an
+<i>item</i> stored by the B-tree (a chunk or an object of a group node).
+The range of values represented by child[
+<i>i</i>] is indicated by key[
+<i>i</i>] and key[
+<i>i</i>+1].
+
+
+<p>
+ The following question must next be answered: &ldquo;Is the value
+ described by key[<i>i</i>] contained in child[<i>i</i>-1] or in child[<i>i</i>]?&rdquo;
+ The answer depends on the type of tree. In trees for groups (node type
+ 0) the object described by key[<i>i</i>] is the greatest object
+ contained in child[<i>i</i>-1] while in chunk trees (node type 1) the
+ chunk described by key[<i>i</i>] is the least chunk in child[<i>i</i>].
+</p>
+
+<p>That means that key[0] for group trees is sometimes unused; it
+ points to offset zero in the heap, which is always the empty string and
+ compares as &ldquo;less-than&rdquo; any valid object name.</p>
+
+<p>
+ And key[<i>N</i>] for chunk trees is sometimes unused; it contains a
+ chunk offset which compares as &ldquo;greater-than&rdquo; any other
+ chunk offset and has a chunk byte size of zero to indicate that it is
+ not actually allocated.
+</p>
+
+<br />
+<h4>
+ <a name="V2Btrees"> III.A.2. Disk Format: Level 1A2 - Version 2
+ B-trees</a>
+</h4>
+
+<p>
+ Version 2 B-trees are &ldquo;traditional&rdquo; B-trees, with one major
+ difference. Instead of just using a simple pointer (or address in the
+ file) to a child of an internal node, the pointer to the child node
+ contains two additional pieces of information: the number of records in
+ the child node itself, and the total number of records in the child
+ node and all its descendants. Storing this additional information
+ allows fast array-like indexing to locate the n<sup>th</sup> record in
+ the B-tree.
+</p>
+
+<p>
+ The entry into a version 2 B-tree is a header which contains global
+ information about the structure of the B-tree. The <em>root node
+ address</em> field in the header points to the B-tree root node, which is
+ either an internal or leaf node, depending on the value in the
+ header&rsquo;s <em>depth</em> field. An internal node consists of
+ records plus pointers to further leaf or internal nodes in the tree. A
+ leaf node consists of solely of records. The format of the records
+ depends on the B-tree type (stored in the header).
+</p>
+
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree Header</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
-
- <tr>
- <td colspan="4">Signature</td>
- </tr>
- <tr>
- <td>Version</td>
- <td>Type</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
- <tr>
- <td colspan="4">Node Size</td>
- </tr>
- <tr>
- <td colspan="2">Record Size</td>
- <td colspan="2">Depth</td>
- </tr>
- <tr>
- <td>Split Percent</td>
- <td>Merge Percent</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
- <tr>
- <td colspan="4"><br />Root Node Address<sup>O</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="2">Number of Records in Root Node</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
- <tr>
- <td colspan="4"><br />Total Number of Records in B-tree<sup>L</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4">Checksum</td>
- </tr>
- </table>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
- <table class="note">
+ </tr>
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <td colspan="4">Signature</td>
+ </tr>
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td>Version</td>
+ <td>Type</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+ <tr>
+ <td colspan="4">Node Size</td>
+ </tr>
+ <tr>
+ <td colspan="2">Record Size</td>
+ <td colspan="2">Depth</td>
+ </tr>
+ <tr>
+ <td>Split Percent</td>
+ <td>Merge Percent</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Root Node Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="2">Number of Records in Root Node</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Total Number of Records in B-tree<sup>L</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4">Checksum</td>
+ </tr>
+ </table>
- </div>
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ <tr>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>BTHD</code>&rdquo; is
- used to indicate the header of a version 2 B-link tree node.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td>
- <p>The version number for this B-tree header. This document
- describes version 0.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Type</p></td>
- <td>
- <p>This field indicates the type of B-tree:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
- <tr>
- <td align="center">0</td>
- <td>A &ldquo;testing&rdquo; B-tree, this value should <em>not</em> be
- used for storing records in actual HDF5 files.
- </td>
- </tr>
- <tr>
- <td align="center">1</td>
- <td>This B-tree is used for indexing indirectly accessed,
- non-filtered &lsquo;huge&rsquo; fractal heap objects.
- </td>
- </tr>
- <tr>
- <td align="center">2</td>
- <td>This B-tree is used for indexing indirectly accessed,
- filtered &lsquo;huge&rsquo; fractal heap objects.
- </td>
- </tr>
- <tr>
- <td align="center">3</td>
- <td>This B-tree is used for indexing directly accessed,
- non-filtered &lsquo;huge&rsquo; fractal heap objects.
- </td>
- </tr>
- <tr>
- <td align="center">4</td>
- <td>This B-tree is used for indexing directly accessed,
- filtered &lsquo;huge&rsquo; fractal heap objects.
- </td>
- </tr>
- <tr>
- <td align="center">5</td>
- <td>This B-tree is used for indexing the &lsquo;name&rsquo; field for
- links in indexed groups.
- </td>
- </tr>
- <tr>
- <td align="center">6</td>
- <td>This B-tree is used for indexing the &lsquo;creation order&rsquo;
- field for links in indexed groups.
- </td>
- </tr>
- <tr>
- <td align="center">7</td>
- <td>This B-tree is used for indexing shared object header
- messages.
- </td>
- </tr>
- <tr>
- <td align="center">8</td>
- <td>This B-tree is used for indexing the &lsquo;name&rsquo; field for
- indexed attributes.
- </td>
- </tr>
- <tr>
- <td align="center">9</td>
- <td>This B-tree is used for indexing the &lsquo;creation order&rsquo;
- field for indexed attributes.
- </td>
- </tr>
- </table></p>
- <p>The format of records for each type is described below.</p>
- </td>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>BTHD</code>
+ &rdquo; is used to indicate the header of a version 2 B-link tree
+ node.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>The version number for this B-tree header. This document
+ describes version 0.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Type</p></td>
+ <td>
+ <p>This field indicates the type of B-tree:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+ <tr>
+ <td align="center">0</td>
+ <td>A &ldquo;testing&rdquo; B-tree, this value should <em>not</em>
+ be used for storing records in actual HDF5 files.
+ </td>
+ </tr>
+ <tr>
+ <td align="center">1</td>
+ <td>This B-tree is used for indexing indirectly accessed,
+ non-filtered &lsquo;huge&rsquo; fractal heap objects.</td>
+ </tr>
+ <tr>
+ <td align="center">2</td>
+ <td>This B-tree is used for indexing indirectly accessed,
+ filtered &lsquo;huge&rsquo; fractal heap objects.</td>
+ </tr>
+ <tr>
+ <td align="center">3</td>
+ <td>This B-tree is used for indexing directly accessed,
+ non-filtered &lsquo;huge&rsquo; fractal heap objects.</td>
+ </tr>
+ <tr>
+ <td align="center">4</td>
+ <td>This B-tree is used for indexing directly accessed,
+ filtered &lsquo;huge&rsquo; fractal heap objects.</td>
+ </tr>
+ <tr>
+ <td align="center">5</td>
+ <td>This B-tree is used for indexing the &lsquo;name&rsquo;
+ field for links in indexed groups.</td>
+ </tr>
+ <tr>
+ <td align="center">6</td>
+ <td>This B-tree is used for indexing the &lsquo;creation
+ order&rsquo; field for links in indexed groups.</td>
+ </tr>
+ <tr>
+ <td align="center">7</td>
+ <td>This B-tree is used for indexing shared object header
+ messages.</td>
+ </tr>
+ <tr>
+ <td align="center">8</td>
+ <td>This B-tree is used for indexing the &lsquo;name&rsquo;
+ field for indexed attributes.</td>
+ </tr>
+ <tr>
+ <td align="center">9</td>
+ <td>This B-tree is used for indexing the &lsquo;creation
+ order&rsquo; field for indexed attributes.</td>
+ </tr>
+ </table>
+ <p></p>
+ <p>The format of records for each type is described below.</p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Node Size</p></td>
- <td>
- <p>This is the size in bytes of all B-tree nodes.
- </p>
- </td>
+ <td><p>Node Size</p></td>
+ <td>
+ <p>This is the size in bytes of all B-tree nodes.</p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Record Size</p></td>
- <td>
- <p>This field is the size in bytes of the B-tree record.
- </p>
- </td>
+ <td><p>Record Size</p></td>
+ <td>
+ <p>This field is the size in bytes of the B-tree record.</p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Depth</p></td>
- <td>
- <p>This is the depth of the B-tree.
- </p>
- </td>
+ <td><p>Depth</p></td>
+ <td>
+ <p>This is the depth of the B-tree.</p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Split Percent</p></td>
- <td>
- <p>The percent full that a node needs to increase above before it
- is split.
- </p>
- </td>
+ <td><p>Split Percent</p></td>
+ <td>
+ <p>The percent full that a node needs to increase above before
+ it is split.</p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Merge Percent</p></td>
- <td>
- <p>The percent full that a node needs to be decrease below before it
- is split.
- </p>
- </td>
+ <td><p>Merge Percent</p></td>
+ <td>
+ <p>The percent full that a node needs to be decrease below
+ before it is split.</p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Root Node Address</p></td>
- <td>
- <p>This is the address of the root B-tree node. A B-tree with
- no records will have the <a href="#UndefinedAddress">undefined
- address</a> in this field.
- </p>
- </td>
+ <td><p>Root Node Address</p></td>
+ <td>
+ <p>
+ This is the address of the root B-tree node. A B-tree with no
+ records will have the <a href="#UndefinedAddress">undefined
+ address</a> in this field.
+ </p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Number of Records in Root Node</p></td>
- <td>
- <p>This is the number of records in the root node.
- </p>
- </td>
+ <td><p>Number of Records in Root Node</p></td>
+ <td>
+ <p>This is the number of records in the root node.</p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Total Number of Records in B-tree</p></td>
- <td>
- <p>This is the total number of records in the entire B-tree.
- </p>
- </td>
+ <td><p>Total Number of Records in B-tree</p></td>
+ <td>
+ <p>This is the total number of records in the entire B-tree.</p>
+ </td>
</tr>
<tr valign="top">
- <td><p>Checksum</p></td>
- <td>
- <p>This is the checksum for the B-tree header.
- </p>
- </td>
+ <td><p>Checksum</p></td>
+ <td>
+ <p>This is the checksum for the B-tree header.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree Internal Node
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree Internal Node</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td colspan="4">Signature</td>
</tr>
<tr>
- <td>Version</td>
- <td>Type</td>
- <td colspan="2">Records 0, 1, 2...N-1 <em>(variable size)</em></td>
+ <td>Version</td>
+ <td>Type</td>
+ <td colspan="2">Records 0, 1, 2...N-1 <em>(variable size)</em></td>
</tr>
- <tr>
- <td colspan="4"><br />Child Node Pointer 0<sup>O</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Number of Records N<sub>0</sub> for Child Node 0 <em>(variable size)</em></td>
- </tr>
- <tr>
- <td colspan="4"><br />Total Number of Records for Child Node 0 <em>(optional, variable size)</em></td>
- </tr>
- <tr>
- <td colspan="4"><br />Child Node Pointer 1<sup>O</sup><br /><br /></td>
- </tr>
- <td colspan="4"><br />Number of Records N<sub>1</sub> for Child Node 1 <em>(variable size)</em></td>
- </tr>
- <tr>
- <td colspan="4"><br />Total Number of Records for Child Node 1 <em>(optional, variable size)</em></td>
- </tr>
- <tr>
- <td colspan="4">...</td>
- </tr>
- <tr>
- <td colspan="4"><br />Child Node Pointer N<sup>O</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Number of Records N<sub>n</sub> for Child Node N <em>(variable size)</em></td>
- </tr>
- <tr>
- <td colspan="4"><br />Total Number of Records for Child Node N <em>(optional, variable size)</em></td>
- </tr>
- <tr>
- <td colspan="4">Checksum</td>
- </tr>
- </table>
+ <tr>
+ <td colspan="4"><br />Child Node Pointer 0<sup>O</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Number of Records N<sub>0</sub> for Child
+ Node 0 <em>(variable size)</em></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Total Number of Records for Child Node 0
+ <em>(optional, variable size)</em></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Child Node Pointer 1<sup>O</sup><br />
+ <br /></td>
+ </tr>
+ <td colspan="4"><br />Number of Records N<sub>1</sub> for Child
+ Node 1 <em>(variable size)</em></td>
+ <tr></tr>
+ <tr>
+ <td colspan="4"><br />Total Number of Records for Child Node 1
+ <em>(optional, variable size)</em></td>
+ </tr>
+ <tr>
+ <td colspan="4">...</td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Child Node Pointer N<sup>O</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Number of Records N<sub>n</sub> for Child
+ Node N <em>(variable size)</em></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Total Number of Records for Child Node N
+ <em>(optional, variable size)</em></td>
+ </tr>
+ <tr>
+ <td colspan="4">Checksum</td>
+ </tr>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
- </div>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>BTIN</code>&rdquo; is
- used to indicate the internal node of a B-link tree.
- </p>
- </td>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>BTIN</code>
+ &rdquo; is used to indicate the internal node of a B-link tree.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Version</p></td>
- <td>
- <p>The version number for this B-tree internal node.
- This document describes version 0.
- </p>
- </td>
+ <td><p>Version</p></td>
+ <td>
+ <p>The version number for this B-tree internal node. This
+ document describes version 0.</p>
+ </td>
</tr>
<tr>
- <td><p>Type</p></td>
- <td>
- <p>This field is the type of the B-tree node. It should always
- be the same as the B-tree type in the header.
- </p>
- </td>
+ <td><p>Type</p></td>
+ <td>
+ <p>This field is the type of the B-tree node. It should always
+ be the same as the B-tree type in the header.</p>
+ </td>
</tr>
<tr>
- <td><p>Records</p></td>
- <td>
- <p>The size of this field is determined by the number of records
- for this node and the record size (from the header). The format
- of records depends on the type of B-tree.
- </p>
- </td>
+ <td><p>Records</p></td>
+ <td>
+ <p>The size of this field is determined by the number of records
+ for this node and the record size (from the header). The format of
+ records depends on the type of B-tree.</p>
+ </td>
</tr>
<tr>
- <td><p>Child Node Pointer</p></td>
- <td>
- <p>This field is the address of the child node pointed to by the
- internal node.
- </p>
- </td>
+ <td><p>Child Node Pointer</p></td>
+ <td>
+ <p>This field is the address of the child node pointed to by the
+ internal node.</p>
+ </td>
</tr>
<tr>
- <td><p>Number of Records in Child Node</p></td>
- <td>
- <p>This is the number of records in the child node pointed to by
- the corresponding <em>Node Pointer</em>.
- </p>
- <p>The number of bytes used to store this field is determined by
- the maximum possible number of records able to be stored in the
- child node.
- </p>
- <p>
- The maximum number of records in a child node is computed
- in the following way:
-
+ <td><p>Number of Records in Child Node</p></td>
+ <td>
+ <p>
+ This is the number of records in the child node pointed to by the
+ corresponding <em>Node Pointer</em>.
+ </p>
+ <p>The number of bytes used to store this field is determined by
+ the maximum possible number of records able to be stored in the
+ child node.</p>
+ <p>The maximum number of records in a child node is computed in
+ the following way:</p>
<ul>
- <li>Subtract the fixed size overhead for
- the child node (for example, its signature, version,
- checksum, and so on and <em>one</em> pointer triplet
- of information for the child node (because there is one
- more pointer triplet than records in each internal node))
- from the size of nodes for the B-tree. </li>
- <li>Divide that result by the size of a record plus the
- pointer triplet of information stored to reach each
- child node from this node.
+ <li>Subtract the fixed size overhead for the child node (for
+ example, its signature, version, checksum, and so on and <em>one</em>
+ pointer triplet of information for the child node (because there
+ is one more pointer triplet than records in each internal node))
+ from the size of nodes for the B-tree.
+ </li>
+ <li>Divide that result by the size of a record plus the
+ pointer triplet of information stored to reach each child node
+ from this node.</li>
</ul>
- </p>
- <p>
- Note that leaf nodes do not encode any
- child pointer triplets, so the maximum number of records in a
- leaf node is just the node size minus the leaf node overhead,
- divided by the record size.
- </p>
- <p>
- Also note that the first level of internal nodes above the
- leaf nodes do not encode the <em>Total Number of Records in Child
- Node</em> value in the child pointer triplets (since it is the
- same as the <em>Number of Records in Child Node</em>), so the
- maximum number of records in these nodes is computed with the
- equation above, but using (<em>Child Pointer</em>, <em>Number of
- Records in Child Node</em>) pairs instead of triplets.
- </p>
- <p>
- The number of
- bytes used to encode this field is the least number of bytes
- required to encode the maximum number of records in a child
- node value for the child nodes below this level
- in the B-tree.
- </p>
- <p>
- For example, if the maximum number of child records is
- 123, one byte will be used to encode these values in this
- node; if the maximum number of child records is
- 20000, two bytes will be used to encode these values in this
- node; and so on. The maximum number of bytes used to
- encode these values is 8 (in other words, an unsigned
- 64-bit integer).
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Total Number of Records in Child Node</p></td>
- <td>
- <p>This is the total number of records for the node pointed to by
- the corresponding <em>Node Pointer</em> and all its children.
- This field exists only in nodes whose depth in the B-tree node
- is greater than 1 (in other words, the &ldquo;twig&rdquo;
- internal nodes, just above leaf nodes, do not store this
- field in their child node pointers).
- </p>
- <p>The number of bytes used to store this field is determined by
- the maximum possible number of records able to be stored in the
- child node and its descendants.
- </p>
- <p>
- The maximum possible number of records able to be stored in a
- child node and its descendants is computed iteratively, in the
- following way: The maximum number of records in a leaf node
- is computed, then that value is used to compute the maximum
- possible number of records in the first level of internal nodes
- above the leaf nodes. Multiplying these two values together
- determines the maximum possible number of records in child node
- pointers for the level of nodes two levels above leaf nodes.
- This process is continued up to any level in the B-tree.
- </p>
- <p>
- The number of bytes used to encode this value is computed in
- the same way as for the <em>Number of Records in Child Node</em>
- field.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Checksum</p></td>
- <td>
- <p>This is the checksum for this node.
- </p>
- </td>
+ <p></p>
+ <p>Note that leaf nodes do not encode any child pointer
+ triplets, so the maximum number of records in a leaf node is just
+ the node size minus the leaf node overhead, divided by the record
+ size.</p>
+ <p>
+ Also note that the first level of internal nodes above the leaf
+ nodes do not encode the <em>Total Number of Records in Child
+ Node</em> value in the child pointer triplets (since it is the same as
+ the <em>Number of Records in Child Node</em>), so the maximum
+ number of records in these nodes is computed with the equation
+ above, but using (<em>Child Pointer</em>, <em>Number of
+ Records in Child Node</em>) pairs instead of triplets.
+ </p>
+ <p>The number of bytes used to encode this field is the least
+ number of bytes required to encode the maximum number of records in
+ a child node value for the child nodes below this level in the
+ B-tree.</p>
+ <p>For example, if the maximum number of child records is 123,
+ one byte will be used to encode these values in this node; if the
+ maximum number of child records is 20000, two bytes will be used to
+ encode these values in this node; and so on. The maximum number of
+ bytes used to encode these values is 8 (in other words, an unsigned
+ 64-bit integer).</p>
+ </td>
</tr>
- </table>
- </div>
+ <tr>
+ <td><p>Total Number of Records in Child Node</p></td>
+ <td>
+ <p>
+ This is the total number of records for the node pointed to by the
+ corresponding <em>Node Pointer</em> and all its children. This
+ field exists only in nodes whose depth in the B-tree node is
+ greater than 1 (in other words, the &ldquo;twig&rdquo; internal
+ nodes, just above leaf nodes, do not store this field in their
+ child node pointers).
+ </p>
+ <p>The number of bytes used to store this field is determined by
+ the maximum possible number of records able to be stored in the
+ child node and its descendants.</p>
+ <p>The maximum possible number of records able to be stored in a
+ child node and its descendants is computed iteratively, in the
+ following way: The maximum number of records in a leaf node is
+ computed, then that value is used to compute the maximum possible
+ number of records in the first level of internal nodes above the
+ leaf nodes. Multiplying these two values together determines the
+ maximum possible number of records in child node pointers for the
+ level of nodes two levels above leaf nodes. This process is
+ continued up to any level in the B-tree.</p>
+ <p>
+ The number of bytes used to encode this value is computed in the
+ same way as for the <em>Number of Records in Child Node</em> field.
+ </p>
+ </td>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree Leaf Node
- </caption>
+ <tr>
+ <td><p>Checksum</p></td>
+ <td>
+ <p>This is the checksum for this node.</p>
+ </td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree Leaf Node</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td colspan="4">Signature</td>
</tr>
<tr>
- <td>Version</td>
- <td>Type</td>
- <td colspan="2">Record 0, 1, 2...N-1 <em>(variable size)</em></td>
- </tr>
- <tr>
- <td colspan="4">Checksum</td>
- </tr>
- </table>
- </div>
+ <td>Version</td>
+ <td>Type</td>
+ <td colspan="2">Record 0, 1, 2...N-1 <em>(variable size)</em></td>
+ </tr>
+ <tr>
+ <td colspan="4">Checksum</td>
+ </tr>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>BTLF</code>&ldquo; is
- used to indicate the leaf node of a version 2 B-link tree.
- </p>
- </td>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>BTLF</code>
+ &ldquo; is used to indicate the leaf node of a version 2 B-link
+ tree.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Version</p></td>
- <td>
- <p>The version number for this B-tree leaf node.
- This document describes version 0.
- </p>
- </td>
+ <td><p>Version</p></td>
+ <td>
+ <p>The version number for this B-tree leaf node. This document
+ describes version 0.</p>
+ </td>
</tr>
<tr>
- <td><p>Type</p></td>
- <td>
- <p>This field is the type of the B-tree node. It should always
- be the same as the B-tree type in the header.
- </p>
- </td>
- </tr>
+ <td><p>Type</p></td>
+ <td>
+ <p>This field is the type of the B-tree node. It should always
+ be the same as the B-tree type in the header.</p>
+ </td>
+ </tr>
<tr>
- <td><p>Records</p></td>
- <td>
- <p>The size of this field is determined by the number of records
- for this node and the record size (from the header). The format
- of records depends on the type of B-tree.
- </p>
- </td>
+ <td><p>Records</p></td>
+ <td>
+ <p>The size of this field is determined by the number of records
+ for this node and the record size (from the header). The format of
+ records depends on the type of B-tree.</p>
+ </td>
</tr>
<tr>
- <td><p>Checksum</p></td>
- <td>
- <p>This is the checksum for this node.
- </p>
- </td>
+ <td><p>Checksum</p></td>
+ <td>
+ <p>This is the checksum for this node.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <p>The record layout for each stored (in other words, non-testing)
+<br />
+<p>The record layout for each stored (in other words, non-testing)
B-tree type is as follows:</p>
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree, Type 1 Record Layout - Indirectly Accessed, Non-Filtered,
- &lsquo;Huge&rsquo; Fractal Heap Objects
- </caption>
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree, Type 1 Record Layout - Indirectly
+ Accessed, Non-Filtered, &lsquo;Huge&rsquo; Fractal Heap Objects</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ </tr>
<tr>
- <td colspan="4"><br />Huge Object Address<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Huge Object Address<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Huge Object Length<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Huge Object Length<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Huge Object ID<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Huge Object ID<sup>L</sup><br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Huge Object Address</p></td>
- <td>
- <p>The address of the huge object in the file.
- </p>
- </td>
+ <td><p>Huge Object Address</p></td>
+ <td>
+ <p>The address of the huge object in the file.</p>
+ </td>
</tr>
<tr>
- <td><p>Huge Object Length</p></td>
- <td>
- <p>The length of the huge object in the file.
- </p>
- </td>
+ <td><p>Huge Object Length</p></td>
+ <td>
+ <p>The length of the huge object in the file.</p>
+ </td>
</tr>
<tr>
- <td><p>Huge Object ID</p></td>
- <td>
- <p>The heap ID for the huge object.
- </p>
- </td>
+ <td><p>Huge Object ID</p></td>
+ <td>
+ <p>The heap ID for the huge object.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree, Type 2 Record Layout - Indirectly Accessed, Filtered,
- &lsquo;Huge&rsquo; Fractal Heap Objects
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree, Type 2 Record Layout - Indirectly
+ Accessed, Filtered, &lsquo;Huge&rsquo; Fractal Heap Objects</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4"><br />Filtered Huge Object Address<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Filtered Huge Object Address<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Filtered Huge Object Length<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Filtered Huge Object Length<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4">Filter Mask</td>
+ <td colspan="4">Filter Mask</td>
</tr>
<tr>
- <td colspan="4"><br />Filtered Huge Object Memory Size<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Filtered Huge Object Memory Size<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Huge Object ID<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Huge Object ID<sup>L</sup><br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Filtered Huge Object Address</p></td>
- <td>
- <p>The address of the filtered huge object in the file.
- </p>
- </td>
+ <td><p>Filtered Huge Object Address</p></td>
+ <td>
+ <p>The address of the filtered huge object in the file.</p>
+ </td>
</tr>
<tr>
- <td><p>Filtered Huge Object Length</p></td>
- <td>
- <p>The length of the filtered huge object in the file.
- </p>
- </td>
+ <td><p>Filtered Huge Object Length</p></td>
+ <td>
+ <p>The length of the filtered huge object in the file.</p>
+ </td>
</tr>
<tr>
- <td><p>Filter Mask</p></td>
- <td>
- <p>A 32-bit bit field indicating which filters have been skipped for
- this chunk. Each filter has an index number in the pipeline
- (starting at 0, with the first filter to apply) and if that
- filter is skipped, the bit corresponding to its index is set.
- </p>
- </td>
+ <td><p>Filter Mask</p></td>
+ <td>
+ <p>A 32-bit bit field indicating which filters have been skipped
+ for this chunk. Each filter has an index number in the pipeline
+ (starting at 0, with the first filter to apply) and if that filter
+ is skipped, the bit corresponding to its index is set.</p>
+ </td>
</tr>
<tr>
- <td><p>Filtered Huge Object Memory Size</p></td>
- <td>
- <p>The size of the de-filtered huge object in memory.
- </p>
- </td>
+ <td><p>Filtered Huge Object Memory Size</p></td>
+ <td>
+ <p>The size of the de-filtered huge object in memory.</p>
+ </td>
</tr>
<tr>
- <td><p>Huge Object ID</p></td>
- <td>
- <p>The heap ID for the huge object.
- </p>
- </td>
+ <td><p>Huge Object ID</p></td>
+ <td>
+ <p>The heap ID for the huge object.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree, Type 3 Record Layout - Directly Accessed, Non-Filtered,
- &lsquo;Huge&rsquo; Fractal Heap Objects
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree, Type 3 Record Layout - Directly
+ Accessed, Non-Filtered, &lsquo;Huge&rsquo; Fractal Heap Objects</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ </tr>
<tr>
- <td colspan="4"><br />Huge Object Address<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Huge Object Address<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Huge Object Length<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Huge Object Length<sup>L</sup><br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Huge Object Address</p></td>
- <td>
- <p>The address of the huge object in the file.
- </p>
- </td>
+ <td><p>Huge Object Address</p></td>
+ <td>
+ <p>The address of the huge object in the file.</p>
+ </td>
</tr>
<tr>
- <td><p>Huge Object Length</p></td>
- <td>
- <p>The length of the huge object in the file.
- </p>
- </td>
+ <td><p>Huge Object Length</p></td>
+ <td>
+ <p>The length of the huge object in the file.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree, Type 4 Record Layout - Directly Accessed, Filtered,
- &lsquo;Huge&rsquo; Fractal Heap Objects
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree, Type 4 Record Layout - Directly
+ Accessed, Filtered, &lsquo;Huge&rsquo; Fractal Heap Objects</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4"><br />Filtered Huge Object Address<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Filtered Huge Object Address<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Filtered Huge Object Length<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Filtered Huge Object Length<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4">Filter Mask</td>
+ <td colspan="4">Filter Mask</td>
</tr>
<tr>
- <td colspan="4"><br />Filtered Huge Object Memory Size<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Filtered Huge Object Memory Size<sup>L</sup><br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Filtered Huge Object Address</p></td>
- <td>
- <p>The address of the filtered huge object in the file.
- </p>
- </td>
+ <td><p>Filtered Huge Object Address</p></td>
+ <td>
+ <p>The address of the filtered huge object in the file.</p>
+ </td>
</tr>
<tr>
- <td><p>Filtered Huge Object Length</p></td>
- <td>
- <p>The length of the filtered huge object in the file.
- </p>
- </td>
+ <td><p>Filtered Huge Object Length</p></td>
+ <td>
+ <p>The length of the filtered huge object in the file.</p>
+ </td>
</tr>
<tr>
- <td><p>Filter Mask</p></td>
- <td>
- <p>A 32-bit bit field indicating which filters have been skipped for
- this chunk. Each filter has an index number in the pipeline
- (starting at 0, with the first filter to apply) and if that
- filter is skipped, the bit corresponding to its index is set.
- </p>
- </td>
+ <td><p>Filter Mask</p></td>
+ <td>
+ <p>A 32-bit bit field indicating which filters have been skipped
+ for this chunk. Each filter has an index number in the pipeline
+ (starting at 0, with the first filter to apply) and if that filter
+ is skipped, the bit corresponding to its index is set.</p>
+ </td>
</tr>
<tr>
- <td><p>Filtered Huge Object Memory Size</p></td>
- <td>
- <p>The size of the de-filtered huge object in memory.
- </p>
- </td>
+ <td><p>Filtered Huge Object Memory Size</p></td>
+ <td>
+ <p>The size of the de-filtered huge object in memory.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree, Type 5 Record Layout - Link Name for Indexed Group
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree, Type 5 Record Layout - Link Name
+ for Indexed Group</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ </tr>
<tr>
- <td colspan="4">Hash of Name</td>
+ <td colspan="4">Hash of Name</td>
</tr>
<tr>
- <td colspan="4">ID <em>(bytes 1-4)</em></td>
- </tr>
+ <td colspan="4">ID <em>(bytes 1-4)</em></td>
+ </tr>
<tr>
- <td colspan="3">ID <em>(bytes 5-7)</em></td>
- </tr>
+ <td colspan="3">ID <em>(bytes 5-7)</em></td>
+ </tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Hash</p></td>
- <td>
- <p>This field is hash value of the name for the link. The hash
- value is the Jenkins&rsquo; lookup3 checksum algorithm applied to
- the link&rsquo;s name.
- </p>
- </td>
+ <td><p>Hash</p></td>
+ <td>
+ <p>This field is hash value of the name for the link. The hash
+ value is the Jenkins&rsquo; lookup3 checksum algorithm applied to
+ the link&rsquo;s name.</p>
+ </td>
</tr>
<tr>
- <td><p>ID</p></td>
- <td>
- <p>This is a 7-byte sequence of bytes and is the heap ID for the
- link record in the group&rsquo;s fractal heap.</p>
- </td>
+ <td><p>ID</p></td>
+ <td>
+ <p>This is a 7-byte sequence of bytes and is the heap ID for the
+ link record in the group&rsquo;s fractal heap.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree, Type 6 Record Layout - Creation Order for Indexed Group
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree, Type 6 Record Layout - Creation
+ Order for Indexed Group</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4"><br />Creation Order <em>(8 bytes)</em><br /><br /></td>
+ <td colspan="4"><br />Creation Order <em>(8 bytes)</em><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4">ID <em>(bytes 1-4)</em></td>
+ <td colspan="4">ID <em>(bytes 1-4)</em></td>
</tr>
<tr>
- <td colspan="3">ID <em>(bytes 5-7)</em></td>
+ <td colspan="3">ID <em>(bytes 5-7)</em></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Creation Order</p></td>
- <td>
- <p>This field is the creation order value for the link.
- </p>
- </td>
+ <td><p>Creation Order</p></td>
+ <td>
+ <p>This field is the creation order value for the link.</p>
+ </td>
</tr>
<tr>
- <td><p>ID</p></td>
- <td>
- <p>This is a 7-byte sequence of bytes and is the heap ID for the
- link record in the group&rsquo;s fractal heap.</p>
- </td>
+ <td><p>ID</p></td>
+ <td>
+ <p>This is a 7-byte sequence of bytes and is the heap ID for the
+ link record in the group&rsquo;s fractal heap.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree, Type 7 Record Layout - Shared Object Header Messages (Sub-Type 0 - Message in Heap)
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree, Type 7 Record Layout - Shared
+ Object Header Messages (Sub-Type 0 - Message in Heap)</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan>Message Location</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td colspan>Message Location</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4">Hash</td>
+ <td colspan="4">Hash</td>
</tr>
<tr>
- <td colspan="4">Reference Count</td>
+ <td colspan="4">Reference Count</td>
</tr>
<tr>
- <td colspan="4"><br />Heap ID <em>(8 bytes)</em><br /><br /></td>
+ <td colspan="4"><br />Heap ID <em>(8 bytes)</em><br />
+ <br /></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Message Location</p></td>
- <td>
- <p>This field Indicates the location where the message is stored:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
- <tr>
- <td align="center">0</td>
- <td>Shared message is stored in shared message index heap.
- </td>
- </tr>
- <tr>
- <td align="center">1</td>
- <td>Shared message is stored in object header.
- </td>
- </tr>
- </table></p>
- </td>
+ <td><p>Message Location</p></td>
+ <td>
+ <p>This field Indicates the location where the message is
+ stored:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+ <tr>
+ <td align="center">0</td>
+ <td>Shared message is stored in shared message index heap.</td>
+ </tr>
+ <tr>
+ <td align="center">1</td>
+ <td>Shared message is stored in object header.</td>
+ </tr>
+ </table>
+ <p></p>
+ </td>
</tr>
<tr>
- <td><p>Hash</p></td>
- <td>
- <p>This field is hash value of the shared message. The hash
- value is the Jenkins&rsquo; lookup3 checksum algorithm applied to
- the shared message.</p>
- </td>
+ <td><p>Hash</p></td>
+ <td>
+ <p>This field is hash value of the shared message. The hash
+ value is the Jenkins&rsquo; lookup3 checksum algorithm applied to
+ the shared message.</p>
+ </td>
</tr>
<tr>
- <td><p>Reference Count</p></td>
- <td>
- <p>The number of objects which reference this message.</p>
- </td>
+ <td><p>Reference Count</p></td>
+ <td>
+ <p>The number of objects which reference this message.</p>
+ </td>
</tr>
<tr>
- <td><p>Heap ID</p></td>
- <td>
- <p>This is an 8-byte sequence of bytes and is the heap ID for the
- shared message in the shared message index&rsquo;s fractal heap.</p>
- </td>
+ <td><p>Heap ID</p></td>
+ <td>
+ <p>This is an 8-byte sequence of bytes and is the heap ID for
+ the shared message in the shared message index&rsquo;s fractal
+ heap.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree, Type 7 Record Layout - Shared Object Header Messages (Sub-Type 1 - Message in Object Header)
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree, Type 7 Record Layout - Shared
+ Object Header Messages (Sub-Type 1 - Message in Object Header)</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan>Message Location</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td colspan>Message Location</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4">Hash</td>
+ <td colspan="4">Hash</td>
</tr>
<tr>
- <td>Reserved (zero)</td>
- <td>Message Type</td>
- <td colspan="2">Object Header Index</td>
+ <td>Reserved (zero)</td>
+ <td>Message Type</td>
+ <td colspan="2">Object Header Index</td>
</tr>
<tr>
- <td colspan="4"><br />Object Header Address<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Object Header Address<sup>O</sup><br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Message Location</p></td>
- <td>
- <p>This field Indicates the location where the message is stored:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
- <tr>
- <td align="center">0</td>
- <td>Shared message is stored in shared message index heap.
- </td>
- </tr>
- <tr>
- <td align="center">1</td>
- <td>Shared message is stored in object header.
- </td>
- </tr>
- </table></p>
- </td>
+ <td><p>Message Location</p></td>
+ <td>
+ <p>This field Indicates the location where the message is
+ stored:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+ <tr>
+ <td align="center">0</td>
+ <td>Shared message is stored in shared message index heap.</td>
+ </tr>
+ <tr>
+ <td align="center">1</td>
+ <td>Shared message is stored in object header.</td>
+ </tr>
+ </table>
+ <p></p>
+ </td>
</tr>
<tr>
- <td><p>Hash</p></td>
- <td>
- <p>This field is hash value of the shared message. The hash
- value is the Jenkins&rsquo; lookup3 checksum algorithm applied to
- the shared message.</p>
- </td>
+ <td><p>Hash</p></td>
+ <td>
+ <p>This field is hash value of the shared message. The hash
+ value is the Jenkins&rsquo; lookup3 checksum algorithm applied to
+ the shared message.</p>
+ </td>
</tr>
<tr>
- <td><p>Message Type</p></td>
- <td>
- <p>The object header message type of the shared message.</p>
- </td>
+ <td><p>Message Type</p></td>
+ <td>
+ <p>The object header message type of the shared message.</p>
+ </td>
</tr>
<tr>
- <td><p>Object Header Index</p></td>
- <td>
- <p>This field indicates that the shared message is the n<sup>th</sup> message
- of its type in the specified object header.</p>
- </td>
+ <td><p>Object Header Index</p></td>
+ <td>
+ <p>
+ This field indicates that the shared message is the n<sup>th</sup>
+ message of its type in the specified object header.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Object Header Address</p></td>
- <td>
- <p>The address of the object header containing the shared message.</p>
- </td>
+ <td><p>Object Header Address</p></td>
+ <td>
+ <p>The address of the object header containing the shared
+ message.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree, Type 8 Record Layout - Attribute Name for Indexed Attributes
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree, Type 8 Record Layout - Attribute
+ Name for Indexed Attributes</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4"><br />Heap ID <em>(8 bytes)</em><br /><br /></td>
+ <td colspan="4"><br />Heap ID <em>(8 bytes)</em><br />
+ <br /></td>
</tr>
<tr>
- <td colspan>Message Flags</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td colspan>Message Flags</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4">Creation Order</td>
+ <td colspan="4">Creation Order</td>
</tr>
<tr>
- <td colspan="4">Hash of Name</td>
+ <td colspan="4">Hash of Name</td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Heap ID</p></td>
- <td>
- <p>This is an 8-byte sequence of bytes and is the heap ID for the
- attribute in the object&rsquo;s attribute fractal heap.</p>
- </td>
+ <td><p>Heap ID</p></td>
+ <td>
+ <p>This is an 8-byte sequence of bytes and is the heap ID for
+ the attribute in the object&rsquo;s attribute fractal heap.</p>
+ </td>
</tr>
<tr>
- <td><p>Message Flags</p></td>
- <td><p>The object header message flags for the attribute message.</p>
- </td>
+ <td><p>Message Flags</p></td>
+ <td><p>The object header message flags for the attribute
+ message.</p></td>
</tr>
<tr>
- <td><p>Creation Order</p></td>
- <td>
- <p>This field is the creation order value for the attribute.
- </p>
- </td>
+ <td><p>Creation Order</p></td>
+ <td>
+ <p>This field is the creation order value for the attribute.</p>
+ </td>
</tr>
<tr>
- <td><p>Hash</p></td>
- <td>
- <p>This field is hash value of the name for the attribute. The hash
- value is the Jenkins&rsquo; lookup3 checksum algorithm applied to
- the attribute&rsquo;s name.
- </p>
- </td>
+ <td><p>Hash</p></td>
+ <td>
+ <p>This field is hash value of the name for the attribute. The
+ hash value is the Jenkins&rsquo; lookup3 checksum algorithm applied
+ to the attribute&rsquo;s name.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Version 2 B-tree, Type 9 Record Layout- Creation Order for Indexed Attributes
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Version 2 B-tree, Type 9 Record Layout- Creation
+ Order for Indexed Attributes</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4"><br />Heap ID <em>(8 bytes)</em><br /><br /></td>
+ <td colspan="4"><br />Heap ID <em>(8 bytes)</em><br />
+ <br /></td>
</tr>
<tr>
- <td colspan>Message Flags</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td colspan>Message Flags</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4">Creation Order</td>
+ <td colspan="4">Creation Order</td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Heap ID</p></td>
- <td>
- <p>This is an 8-byte sequence of bytes and is the heap ID for the
- attribute in the object&rsquo;s attribute fractal heap.</p>
- </td>
+ <td><p>Heap ID</p></td>
+ <td>
+ <p>This is an 8-byte sequence of bytes and is the heap ID for
+ the attribute in the object&rsquo;s attribute fractal heap.</p>
+ </td>
</tr>
<tr>
- <td><p>Message Flags</p></td>
- <td>
- <p>The object header message flags for the attribute message.</p>
- </td>
+ <td><p>Message Flags</p></td>
+ <td>
+ <p>The object header message flags for the attribute message.</p>
+ </td>
</tr>
<tr>
- <td><p>Creation Order</p></td>
- <td>
- <p>This field is the creation order value for the attribute.
- </p>
- </td>
+ <td><p>Creation Order</p></td>
+ <td>
+ <p>This field is the creation order value for the attribute.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
<br />
-<h3><a name="SymbolTable">
-III.B. Disk Format: Level 1B - Group Symbol Table Nodes</a></h3>
-
- <p>A group is an object internal to the file that allows
- arbitrary nesting of objects within the file (including other groups).
- A group maps a set of link names in the group to a set of relative
- file addresses of objects in the file. Certain metadata for an object to
- which the group points can be cached in the group&rsquo;s symbol table entry in
- addition to being in the object&rsquo;s header.</p>
-
- <p>An HDF5 object name space can be stored hierarchically by
- partitioning the name into components and storing each
- component as a link in a group. The link for a
- non-ultimate component points to the group containing
- the next component. The link for the last
- component points to the object being named.</p>
+<h3>
+ <a name="SymbolTable"> III.B. Disk Format: Level 1B - Group Symbol
+ Table Nodes</a>
+</h3>
+
+<p>A group is an object internal to the file that allows arbitrary
+ nesting of objects within the file (including other groups). A group
+ maps a set of link names in the group to a set of relative file
+ addresses of objects in the file. Certain metadata for an object to
+ which the group points can be cached in the group&rsquo;s symbol table
+ entry in addition to being in the object&rsquo;s header.</p>
+
+<p>An HDF5 object name space can be stored hierarchically by
+ partitioning the name into components and storing each component as a
+ link in a group. The link for a non-ultimate component points to the
+ group containing the next component. The link for the last component
+ points to the object being named.</p>
+
+<p>
+ One implementation of a group is a collection of symbol table nodes
+ indexed by a B-link tree. Each symbol table node contains entries for
+ one or more links. If an attempt is made to add a link to an already
+ full symbol table node containing 2<em>K</em> entries, then the node is
+ split and one node contains <em>K</em> symbols and the other contains <em>K</em>+1
+ symbols.
+</p>
- <p>One implementation of a group is a collection of symbol table nodes
- indexed by a B-link tree. Each symbol table node contains entries
- for one or more links. If an attempt is made to add a link to an already
- full symbol table node containing 2<em>K</em> entries, then the node is
- split and one node contains <em>K</em> symbols and the other contains
- <em>K</em>+1 symbols.</p>
-
- <div align="center">
- <table class="format">
- <caption>
- Symbol Table Node (A Leaf of a B-link tree)
- </caption>
+<div align="center">
+ <table class="format">
+ <caption>Symbol Table Node (A Leaf of a B-link tree)</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td colspan="4">Signature</td>
</tr>
<tr>
- <td>Version Number</td>
- <td>Reserved (zero)</td>
- <td colspan="2">Number of Symbols</td>
+ <td>Version Number</td>
+ <td>Reserved (zero)</td>
+ <td colspan="2">Number of Symbols</td>
</tr>
<tr>
- <td colspan="4"><br /><br />Group Entries<br /><br /><br /></td>
+ <td colspan="4"><br />
+ <br />Group Entries<br />
+ <br />
+ <br /></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>SNOD</code>&rdquo; is
- used to indicate the
- beginning of a symbol table node. This gives file
- consistency checking utilities a better chance of
- reconstructing a damaged file.
- </p>
- </td>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>SNOD</code>
+ &rdquo; is used to indicate the beginning of a symbol table node.
+ This gives file consistency checking utilities a better chance of
+ reconstructing a damaged file.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Version Number</p></td>
- <td>
- <p>The version number for the symbol table node. This
- document describes version 1. (There is no version &lsquo;0&rsquo;
- of the symbol table node)
- </p>
- </td>
+ <td><p>Version Number</p></td>
+ <td>
+ <p>The version number for the symbol table node. This document
+ describes version 1. (There is no version &lsquo;0&rsquo; of the
+ symbol table node)</p>
+ </td>
</tr>
<tr>
- <td><p>Number of Entries</p></td>
- <td>
- <p>Although all symbol table nodes have the same length,
- most contain fewer than the maximum possible number of
- link entries. This field indicates how many entries
- contain valid data. The valid entries are packed at the
- beginning of the symbol table node while the remaining
- entries contain undefined values.
- </p>
- </td>
+ <td><p>Number of Entries</p></td>
+ <td>
+ <p>Although all symbol table nodes have the same length, most
+ contain fewer than the maximum possible number of link entries.
+ This field indicates how many entries contain valid data. The valid
+ entries are packed at the beginning of the symbol table node while
+ the remaining entries contain undefined values.</p>
+ </td>
</tr>
<tr>
- <td><p>Symbol Table Entries</p></td>
- <td>
- <p>Each link has an entry in the symbol table node.
- The format of the entry is described below.
- There are 2<em>K</em> entries in each group node, where
- <em>K</em> is the &ldquo;Group Leaf Node K&rdquo; value from the
- <a href="#Superblock">superblock</a>.
- </p>
- </td>
+ <td><p>Symbol Table Entries</p></td>
+ <td>
+ <p>
+ Each link has an entry in the symbol table node. The format of the
+ entry is described below. There are 2<em>K</em> entries in each
+ group node, where <em>K</em> is the &ldquo;Group Leaf Node K&rdquo;
+ value from the <a href="#Superblock">superblock</a>.
+ </p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
<br />
-<h3><a name="SymbolTableEntry">
-III.C. Disk Format: Level 1C - Symbol Table Entry </a></h3>
+<h3>
+ <a name="SymbolTableEntry"> III.C. Disk Format: Level 1C - Symbol
+ Table Entry </a>
+</h3>
- <p>Each symbol table entry in a symbol table node is designed
- to allow for very fast browsing of stored objects.
- Toward that design goal, the symbol table entries
- include space for caching certain constant metadata from the
- object header.</p>
+<p>Each symbol table entry in a symbol table node is designed to
+ allow for very fast browsing of stored objects. Toward that design
+ goal, the symbol table entries include space for caching certain
+ constant metadata from the object header.</p>
- <div align="center">
- <table class="format">
- <caption>
- Symbol Table Entry
- </caption>
+<div align="center">
+ <table class="format">
+ <caption>Symbol Table Entry</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4"><br />Link Name Offset<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Link Name Offset<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Object Header Address<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Object Header Address<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4">Cache Type</td>
+ <td colspan="4">Cache Type</td>
</tr>
<tr>
- <td colspan="4">Reserved (zero)</td>
+ <td colspan="4">Reserved (zero)</td>
</tr>
<tr>
- <td colspan="4"><br /><br />Scratch-pad Space (16 bytes)<br /><br /><br /></td>
+ <td colspan="4"><br />
+ <br />Scratch-pad Space (16 bytes)<br />
+ <br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Link Name Offset</p></td>
- <td>
- <p>This is the byte offset into the group&rsquo;s local
- heap for the name of the link. The name is null
- terminated.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Object Header Address</p></td>
- <td>
- <p>Every object has an object header which serves as a
- permanent location for the object&rsquo;s metadata. In addition
- to appearing in the object header, some of the object&rsquo;s metadata
- can be cached in the scratch-pad space.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Cache Type</p></td>
- <td>
- <p>The cache type is determined from the object header.
- It also determines the format for the scratch-pad space:
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Type</th>
- <th width="80%" align="left">Description</th>
- </tr>
- <tr>
- <td align="center">0</td>
- <td>No data is cached by the group entry. This
- is guaranteed to be the case when an object header
- has a link count greater than one.
- </td>
- </tr>
- <tr>
- <td align="center">1</td>
- <td>Group object header metadata is cached in the
- scratch-pad space. This implies that the symbol table
- entry refers to another group.
- </td>
- </tr>
- <tr>
- <td align="center">2</td>
- <td>The entry is a symbolic link. The first four bytes
- of the scratch-pad space are the offset into the local
- heap for the link value. The object header address
- will be undefined.
- </td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>Reserved</p></td>
- <td>
- <p>These four bytes are present so that the scratch-pad
- space is aligned on an eight-byte boundary. They are
- always set to zero.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Scratch-pad Space</p></td>
- <td>
- <p>This space is used for different purposes, depending
- on the value of the Cache Type field. Any metadata
- about an object represented in the scratch-pad
- space is duplicated in the object header for that
- object.
- </p>
- <p>
- Furthermore, no data is cached in the group
- entry scratch-pad space if the object header for
- the object has a link count greater than one.
- </p>
- </td>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Link Name Offset</p></td>
+ <td>
+ <p>This is the byte offset into the group&rsquo;s local heap for
+ the name of the link. The name is null terminated.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Object Header Address</p></td>
+ <td>
+ <p>Every object has an object header which serves as a permanent
+ location for the object&rsquo;s metadata. In addition to appearing
+ in the object header, some of the object&rsquo;s metadata can be
+ cached in the scratch-pad space.</p>
+ </td>
</tr>
- </table>
- </div>
+
+ <tr>
+ <td><p>Cache Type</p></td>
+ <td>
+ <p>The cache type is determined from the object header. It also
+ determines the format for the scratch-pad space:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Type</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+ <tr>
+ <td align="center">0</td>
+ <td>No data is cached by the group entry. This is guaranteed
+ to be the case when an object header has a link count greater
+ than one.</td>
+ </tr>
+ <tr>
+ <td align="center">1</td>
+ <td>Group object header metadata is cached in the scratch-pad
+ space. This implies that the symbol table entry refers to another
+ group.</td>
+ </tr>
+ <tr>
+ <td align="center">2</td>
+ <td>The entry is a symbolic link. The first four bytes of the
+ scratch-pad space are the offset into the local heap for the link
+ value. The object header address will be undefined.</td>
+ </tr>
+ </table>
+ <p></p>
+
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Reserved</p></td>
+ <td>
+ <p>These four bytes are present so that the scratch-pad space is
+ aligned on an eight-byte boundary. They are always set to zero.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Scratch-pad Space</p></td>
+ <td>
+ <p>This space is used for different purposes, depending on the
+ value of the Cache Type field. Any metadata about an object
+ represented in the scratch-pad space is duplicated in the object
+ header for that object.</p>
+ <p>Furthermore, no data is cached in the group entry scratch-pad
+ space if the object header for the object has a link count greater
+ than one.</p>
+ </td>
+ </tr>
+ </table>
+</div>
<br />
<h4>Format of the Scratch-pad Space</h4>
- <p>The symbol table entry scratch-pad space is formatted
- according to the value in the Cache Type field.</p>
+<p>The symbol table entry scratch-pad space is formatted according
+ to the value in the Cache Type field.</p>
- <p>If the Cache Type field contains the value zero
- <code>(0)</code> then no information is
- stored in the scratch-pad space.</p>
+<p>
+ If the Cache Type field contains the value zero
+ <code>(0)</code>
+ then no information is stored in the scratch-pad space.
+</p>
- <p>If the Cache Type field contains the value one
- <code>(1)</code>, then the scratch-pad space
- contains cached metadata for another object header
- in the following format:</p>
+<p>
+ If the Cache Type field contains the value one
+ <code>(1)</code>
+ , then the scratch-pad space contains cached metadata for another
+ object header in the following format:
+</p>
- <div align="center">
- <table class="format">
- <caption>
- Object Header Scratch-pad Format
- </caption>
+<div align="center">
+ <table class="format">
+ <caption>Object Header Scratch-pad Format</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4"><br />Address of B-tree<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Address of B-tree<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Address of Name Heap<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Address of Name Heap<sup>O</sup><br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Address of B-tree</p></td>
- <td>
- <p>This is the file address for the root of the
- group&rsquo;s B-tree.
- </p>
- </td>
+ <td><p>Address of B-tree</p></td>
+ <td>
+ <p>This is the file address for the root of the group&rsquo;s
+ B-tree.</p>
+ </td>
</tr>
<tr>
- <td><p>Address of Name Heap</p></td>
- <td>
- <p>This is the file address for the group&rsquo;s local
- heap, in which are stored the group&rsquo;s symbol names.
- </p>
- </td>
+ <td><p>Address of Name Heap</p></td>
+ <td>
+ <p>This is the file address for the group&rsquo;s local heap, in
+ which are stored the group&rsquo;s symbol names.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <p>If the Cache Type field contains the value two
- <code>(2)</code>, then the scratch-pad space
- contains cached metadata for a symbolic link
- in the following format:</p>
+<br />
+<p>
+ If the Cache Type field contains the value two
+ <code>(2)</code>
+ , then the scratch-pad space contains cached metadata for a symbolic
+ link in the following format:
+</p>
- <div align="center">
- <table class="format">
- <caption>
- Symbolic Link Scratch-pad Format
- </caption>
+<div align="center">
+ <table class="format">
+ <caption>Symbolic Link Scratch-pad Format</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4">Offset to Link Value</td>
+ <td colspan="4">Offset to Link Value</td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Offset to Link Value</p></td>
- <td>
- <p>The value of a symbolic link (that is, the name of the
- thing to which it points) is stored in the local heap.
- This field is the 4-byte offset into the local heap for
- the start of the link value, which is null terminated.
- </p>
- </td>
+ <td><p>Offset to Link Value</p></td>
+ <td>
+ <p>The value of a symbolic link (that is, the name of the thing
+ to which it points) is stored in the local heap. This field is the
+ 4-byte offset into the local heap for the start of the link value,
+ which is null terminated.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
<br />
-<h3><a name="LocalHeap">
-III.D. Disk Format: Level 1D - Local Heaps</a></h3>
+<h3>
+ <a name="LocalHeap"> III.D. Disk Format: Level 1D - Local Heaps</a>
+</h3>
- <p>A local heap is a collection of small pieces of data that are particular
- to a single object in the HDF5 file. Objects can be
- inserted and removed from the heap at any time.
- The address of a heap does not change once the heap is created.
- For example, a group stores addresses of objects in symbol table nodes
- with the names of links stored in the group&rsquo;s local heap.
- </p>
+<p>A local heap is a collection of small pieces of data that are
+ particular to a single object in the HDF5 file. Objects can be inserted
+ and removed from the heap at any time. The address of a heap does not
+ change once the heap is created. For example, a group stores addresses
+ of objects in symbol table nodes with the names of links stored in the
+ group&rsquo;s local heap.</p>
- <div align="center">
- <table class="format">
- <caption>
- Local Heap
- </caption>
+<div align="center">
+ <table class="format">
+ <caption>Local Heap</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td colspan="4">Signature</td>
</tr>
<tr>
- <td>Version</td>
- <td colspan="3">Reserved (zero)</td>
+ <td>Version</td>
+ <td colspan="3">Reserved (zero)</td>
</tr>
<tr>
- <td colspan="4"><br />Data Segment Size<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Data Segment Size<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Offset to Head of Free-list<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Offset to Head of Free-list<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Address of Data Segment<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Address of Data Segment<sup>O</sup><br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>HEAP</code>&rdquo;
- is used to indicate the
- beginning of a heap. This gives file consistency
- checking utilities a better chance of reconstructing a
- damaged file.
- </p>
- </td>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>HEAP</code>
+ &rdquo; is used to indicate the beginning of a heap. This gives
+ file consistency checking utilities a better chance of
+ reconstructing a damaged file.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Version</p></td>
- <td>
- <p>Each local heap has its own version number so that new
- heaps can be added to old files. This document
- describes version zero (0) of the local heap.
- </p>
- </td>
+ <td><p>Version</p></td>
+ <td>
+ <p>Each local heap has its own version number so that new heaps
+ can be added to old files. This document describes version zero (0)
+ of the local heap.</p>
+ </td>
</tr>
<tr>
- <td><p>Data Segment Size</p></td>
- <td>
- <p>The total amount of disk memory allocated for the heap
- data. This may be larger than the amount of space
- required by the objects stored in the heap. The extra
- unused space in the heap holds a linked list of free blocks.
- </p>
- </td>
+ <td><p>Data Segment Size</p></td>
+ <td>
+ <p>The total amount of disk memory allocated for the heap data.
+ This may be larger than the amount of space required by the objects
+ stored in the heap. The extra unused space in the heap holds a
+ linked list of free blocks.</p>
+ </td>
</tr>
<tr>
- <td><p>Offset to Head of Free-list</p></td>
- <td>
- <p>This is the offset within the heap data segment of the
- first free block (or the
- <a href="#UndefinedAddress">undefined address</a> if there is no
- free block). The free block contains &ldquo;Size of Lengths&rdquo; bytes that
- are the offset of the next free block (or the
- value &lsquo;1&rsquo; if this is the
- last free block) followed by &ldquo;Size of Lengths&rdquo; bytes that store
- the size of this free block. The size of the free block includes
- the space used to store the offset of the next free block and
- the size of the current block, making the minimum size of a free
- block 2 * &ldquo;Size of Lengths&rdquo;.
- </p>
- </td>
+ <td><p>Offset to Head of Free-list</p></td>
+ <td>
+ <p>
+ This is the offset within the heap data segment of the first free
+ block (or the <a href="#UndefinedAddress">undefined address</a> if
+ there is no free block). The free block contains &ldquo;Size of
+ Lengths&rdquo; bytes that are the offset of the next free block (or
+ the value &lsquo;1&rsquo; if this is the last free block) followed
+ by &ldquo;Size of Lengths&rdquo; bytes that store the size of this
+ free block. The size of the free block includes the space used to
+ store the offset of the next free block and the size of the current
+ block, making the minimum size of a free block 2 * &ldquo;Size of
+ Lengths&rdquo;.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Address of Data Segment</p></td>
- <td>
- <p>The data segment originally starts immediately after
- the heap header, but if the data segment must grow as a
- result of adding more objects, then the data segment may
- be relocated, in its entirety, to another part of the
- file.
- </p>
- </td>
+ <td><p>Address of Data Segment</p></td>
+ <td>
+ <p>The data segment originally starts immediately after the heap
+ header, but if the data segment must grow as a result of adding
+ more objects, then the data segment may be relocated, in its
+ entirety, to another part of the file.</p>
+ </td>
</tr>
- </table>
- </div>
-
- <p>Objects within a local heap should be aligned on an 8-byte boundary.</p>
-
-<br />
-<h3><a name="GlobalHeap">
-III.E. Disk Format: Level 1E - Global Heap</a></h3>
-
- <p>Each HDF5 file has a global heap which stores various types of
- information which is typically shared between datasets. The
- global heap was designed to satisfy these goals:</p>
-
- <ol type="A">
- <li>Repeated access to a heap object must be efficient without
- resulting in repeated file I/O requests. Since global heap
- objects will typically be shared among several datasets, it is
- probable that the object will be accessed repeatedly.</li>
- <li>Collections of related global heap objects should result in
- fewer and larger I/O requests. For instance, a dataset of
- object references will have a global heap object for each
- reference. Reading the entire set of object references
- should result in a few large I/O requests instead of one small
- I/O request for each reference.</li>
- <li>It should be possible to remove objects from the global heap
- and the resulting file hole should be eligible to be reclaimed
- for other uses.</li>
- </ol>
-
-
- <p>The implementation of the heap makes use of the memory management
- already available at the file level and combines that with a new
- object called a <em>collection</em> to achieve goal B. The global heap
- is the set of all collections. Each global heap object belongs to
- exactly one collection and each collection contains one or more global
- heap objects. For the purposes of disk I/O and caching, a collection is
- treated as an atomic object, addressing goal A.
- </p>
-
- <p>When a global heap object is deleted from a collection (which occurs
- when its reference count falls to zero), objects located after the
- deleted object in the collection are packed down toward the beginning
- of the collection and the collection&rsquo;s global heap object 0 is created
- (if possible) or its size is increased to account for the recently
- freed space. There are no gaps between objects in each collection,
- with the possible exception of the final space in the collection, if
- it is not large enough to hold the header for the collection&rsquo;s global
- heap object 0. These features address goal C.
- </p>
-
- <p>The HDF5 Library creates global heap collections as needed, so there may
- be multiple collections throughout the file. The set of all of them is
- abstractly called the &ldquo;global heap&rdquo;, although they do not actually link
- to each other, and there is no global place in the file where you can
- discover all of the collections. The collections are found simply by
- finding a reference to one through another object in the file. For
- example, data of variable-length datatype elements is stored in the
- global heap and is accessed via a global heap ID. The format for
- global heap IDs is described at the end of this section.
- </p>
-
- <div align="center">
- <table class="format">
- <caption>
- A Global Heap Collection
- </caption>
+ </table>
+</div>
+
+<p>Objects within a local heap should be aligned on an 8-byte
+ boundary.</p>
+
+<br />
+<h3>
+ <a name="GlobalHeap"> III.E. Disk Format: Level 1E - Global Heap</a>
+</h3>
+
+<p>Each HDF5 file has a global heap which stores various types of
+ information which is typically shared between datasets. The global heap
+ was designed to satisfy these goals:</p>
+
+<ol type="A">
+ <li>Repeated access to a heap object must be efficient without
+ resulting in repeated file I/O requests. Since global heap objects
+ will typically be shared among several datasets, it is probable that
+ the object will be accessed repeatedly.</li>
+ <li>Collections of related global heap objects should result in
+ fewer and larger I/O requests. For instance, a dataset of object
+ references will have a global heap object for each reference. Reading
+ the entire set of object references should result in a few large I/O
+ requests instead of one small I/O request for each reference.</li>
+ <li>It should be possible to remove objects from the global heap
+ and the resulting file hole should be eligible to be reclaimed for
+ other uses.</li>
+</ol>
+
+
+<p>
+ The implementation of the heap makes use of the memory management
+ already available at the file level and combines that with a new object
+ called a <em>collection</em> to achieve goal B. The global heap is the
+ set of all collections. Each global heap object belongs to exactly one
+ collection and each collection contains one or more global heap
+ objects. For the purposes of disk I/O and caching, a collection is
+ treated as an atomic object, addressing goal A.
+</p>
+
+<p>When a global heap object is deleted from a collection (which
+ occurs when its reference count falls to zero), objects located after
+ the deleted object in the collection are packed down toward the
+ beginning of the collection and the collection&rsquo;s global heap
+ object 0 is created (if possible) or its size is increased to account
+ for the recently freed space. There are no gaps between objects in each
+ collection, with the possible exception of the final space in the
+ collection, if it is not large enough to hold the header for the
+ collection&rsquo;s global heap object 0. These features address goal C.
+</p>
+
+<p>The HDF5 Library creates global heap collections as needed, so
+ there may be multiple collections throughout the file. The set of all
+ of them is abstractly called the &ldquo;global heap&rdquo;, although
+ they do not actually link to each other, and there is no global place
+ in the file where you can discover all of the collections. The
+ collections are found simply by finding a reference to one through
+ another object in the file. For example, data of variable-length
+ datatype elements is stored in the global heap and is accessed via a
+ global heap ID. The format for global heap IDs is described at the end
+ of this section.</p>
+
+<div align="center">
+ <table class="format">
+ <caption>A Global Heap Collection</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td colspan="4">Signature</td>
</tr>
<tr>
- <td>Version</td>
- <td colspan="3">Reserved (zero)</td>
+ <td>Version</td>
+ <td colspan="3">Reserved (zero)</td>
</tr>
<tr>
- <td colspan="4"><br />Collection Size<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Collection Size<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Global Heap Object 1<br /><br /></td>
+ <td colspan="4"><br />Global Heap Object 1<br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Global Heap Object 2<br /><br /></td>
+ <td colspan="4"><br />Global Heap Object 2<br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />...<br /><br /></td>
+ <td colspan="4"><br />...<br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Global Heap Object <em>N</em><br /><br /></td>
+ <td colspan="4"><br />Global Heap Object <em>N</em><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Global Heap Object 0 (free space)<br /><br /></td>
+ <td colspan="4"><br />Global Heap Object 0 (free space)<br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;L&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Lengths&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>GCOL</code>&rdquo;
- is used to indicate the
- beginning of a collection. This gives file consistency
- checking utilities a better chance of reconstructing a
- damaged file.
- </p>
- </td>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>GCOL</code>
+ &rdquo; is used to indicate the beginning of a collection. This
+ gives file consistency checking utilities a better chance of
+ reconstructing a damaged file.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Version</p></td>
- <td>
- <p>Each collection has its own version number so that new
- collections can be added to old files. This document
- describes version one (1) of the collections (there is no
- version zero (0)).
- </p>
- </td>
+ <td><p>Version</p></td>
+ <td>
+ <p>Each collection has its own version number so that new
+ collections can be added to old files. This document describes
+ version one (1) of the collections (there is no version zero (0)).
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Collection Size</p></td>
- <td>
- <p>This is the size in bytes of the entire collection
- including this field. The default (and minimum)
- collection size is 4096 bytes which is a typical file
- system block size. This allows for 127 16-byte heap
- objects plus their overhead (the collection header of 16 bytes
- and the 16 bytes of information about each heap object).
- </p>
- </td>
+ <td><p>Collection Size</p></td>
+ <td>
+ <p>This is the size in bytes of the entire collection including
+ this field. The default (and minimum) collection size is 4096 bytes
+ which is a typical file system block size. This allows for 127
+ 16-byte heap objects plus their overhead (the collection header of
+ 16 bytes and the 16 bytes of information about each heap object).</p>
+ </td>
</tr>
<tr>
- <td><p>Global Heap Object 1 through <em>N</em></p></td>
- <td>
- <p>The objects are stored in any order with no
- intervening unused space.
- </p>
- </td>
+ <td><p>
+ Global Heap Object 1 through <em>N</em>
+ </p></td>
+ <td>
+ <p>The objects are stored in any order with no intervening
+ unused space.</p>
+ </td>
</tr>
<tr>
- <td><p>Global Heap Object 0</p></td>
- <td>
- <p>Global Heap Object 0 (zero), when present, represents the free
- space in the collection. Free space always appears at the end of
- the collection. If the free space is too small to store the header
- for Object 0 (described below) then the header is implied and the
- collection contains no free space.
- </p>
- </td>
+ <td><p>Global Heap Object 0</p></td>
+ <td>
+ <p>Global Heap Object 0 (zero), when present, represents the
+ free space in the collection. Free space always appears at the end
+ of the collection. If the free space is too small to store the
+ header for Object 0 (described below) then the header is implied
+ and the collection contains no free space.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Global Heap Object
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Global Heap Object</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="2">Heap Object Index</td>
- <td colspan="2">Reference Count</td>
+ <td colspan="2">Heap Object Index</td>
+ <td colspan="2">Reference Count</td>
</tr>
<tr>
- <td colspan="4">Reserved (zero)</td>
+ <td colspan="4">Reserved (zero)</td>
</tr>
<tr>
- <td colspan="4"><br />Object Size<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Object Size<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Object Data<br /><br /></td>
+ <td colspan="4"><br />Object Data<br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;L&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Lengths&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Heap Object Index</p></td>
- <td>
- <p>Each object has a unique identification number within a
- collection. The identification numbers are chosen so that
- new objects have the smallest value possible with the
- exception that the identifier <code>0</code> always refers to the
- object which represents all free space within the
- collection.
- </p>
- </td>
+ <td><p>Heap Object Index</p></td>
+ <td>
+ <p>
+ Each object has a unique identification number within a collection.
+ The identification numbers are chosen so that new objects have the
+ smallest value possible with the exception that the identifier
+ <code>0</code>
+ always refers to the object which represents all free space within
+ the collection.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Reference Count</p></td>
- <td>
- <p>All heap objects have a reference count field. An
- object which is referenced from some other part of the
- file will have a positive reference count. The reference
- count for Object 0 is always zero.
- </p>
- </td>
+ <td><p>Reference Count</p></td>
+ <td>
+ <p>All heap objects have a reference count field. An object
+ which is referenced from some other part of the file will have a
+ positive reference count. The reference count for Object 0 is
+ always zero.</p>
+ </td>
</tr>
<tr>
- <td><p>Reserved</p></td>
- <td>
- <p>Zero padding to align next field on an 8-byte boundary.
- </p>
- </td>
+ <td><p>Reserved</p></td>
+ <td>
+ <p>Zero padding to align next field on an 8-byte boundary.</p>
+ </td>
</tr>
<tr>
- <td><p>Object Size</p></td>
- <td>
- <p>This is the size of the object data stored for the object.
- The actual storage space allocated for the object data is rounded
- up to a multiple of eight.
- </p>
- </td>
+ <td><p>Object Size</p></td>
+ <td>
+ <p>This is the size of the object data stored for the object.
+ The actual storage space allocated for the object data is rounded
+ up to a multiple of eight.</p>
+ </td>
</tr>
<tr>
- <td><p>Object Data</p></td>
- <td>
- <p>The object data is treated as a one-dimensional array
- of bytes to be interpreted by the caller.
- </p>
- </td>
+ <td><p>Object Data</p></td>
+ <td>
+ <p>The object data is treated as a one-dimensional array of
+ bytes to be interpreted by the caller.</p>
+ </td>
</tr>
- </table>
+ </table>
- </div>
+</div>
- <br />
- <p>
- The format for the ID used to locate an object in the global heap is
- described here:</p>
+<br />
+<p>The format for the ID used to locate an object in the global heap
+ is described here:</p>
- <div align="center">
- <table class="format">
- <caption>
- Global Heap ID
- </caption>
+<div align="center">
+ <table class="format">
+ <caption>Global Heap ID</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4"><br />Collection Address<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Collection Address<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4">Object Index</td>
+ <td colspan="4">Object Index</td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Collection Address</p></td>
- <td>
- <p>This field is the address of the global heap collection
- where the data object is stored.
- </p>
- </td>
+ <td><p>Collection Address</p></td>
+ <td>
+ <p>This field is the address of the global heap collection where
+ the data object is stored.</p>
+ </td>
</tr>
<tr>
- <td><p>ID</p></td>
- <td>
- <p>This field is the index of the data object within the
- global heap collection.
- </p>
- </td>
+ <td><p>ID</p></td>
+ <td>
+ <p>This field is the index of the data object within the global
+ heap collection.</p>
+ </td>
</tr>
- </table>
- </div>
-
-
-<br />
-<h3><a name="FractalHeap">
-III.F. Disk Format: Level 1F - Fractal Heap</a></h3>
-
- <p>
- Each fractal heap consists of a header and zero or more direct and
- indirect blocks (described below). The header contains general
- information as well as
- initialization parameters for the doubling table. The <em>Root
- Block Address</em> in the header points to the first direct or
- indirect block in the heap.
- </p>
-
- <p>
- Fractal heaps are based on a data structure called a <em>doubling
- table</em>. A doubling table provides a mechanism for quickly
- extending an array-like data structure that minimizes the number of
- empty blocks in the heap, while retaining very fast lookup of any
- element within the array. More information on fractal heaps and
- doubling tables can be found in the RFC
- &ldquo;<a href="Supplements/FractalHeap/PrivateHeap.pdf">Private
- Heaps in HDF5</a>.&rdquo;
- </p>
-
- <p>
- The fractal heap implements the doubling table structure with
- indirect and direct blocks.
- Indirect blocks in the heap do not actually contain data for
- objects in the heap, their &ldquo;size&rdquo; is abstract -
- they represent the indexing structure for locating the
- direct blocks in the doubling table.
- Direct blocks
- contain the actual data for objects stored in the heap.
- </p>
-
- <p>
- All indirect blocks have a constant number of block entries in each
- row, called the <em>width</em> of the doubling table (stored in
- the heap header).
-
- The number
- of rows for each indirect block in the heap is determined by the
- size of the block that the indirect block represents in the
- doubling table (calculation of this is shown below) and is
- constant, except for the &ldquo;root&rdquo;
- indirect block, which expands and shrinks its number of rows as
- needed.
- </p>
-
- <p>
- Blocks in the first <em>two</em> rows of an indirect block
- are <em>Starting Block Size</em> number of bytes in size,
- and the blocks in each subsequent row are twice the size of
- the blocks in the previous row. In other words, blocks in
- the third row are twice the <em>Starting Block Size</em>,
- blocks in the fourth row are four times the
- <em>Starting Block Size</em>, and so on. Entries for
- blocks up to the <em>Maximum Direct Block Size</em> point to
- direct blocks, and entries for blocks greater than that size
- point to further indirect blocks (which have their own
- entries for direct and indirect blocks).
- </p>
-
- <p>
- The number of rows of blocks, <em>nrows</em>, in an
- indirect block of size <em>iblock_size</em> is given by the
- following expression:
- <br /> <br />
- <em>nrows</em> = (log<sub>2</sub>(<em>iblock_size</em>) -
- log<sub>2</sub>(<em>&lt;Starting Block Size&gt;</em> *
- <em>&lt;Width&gt;</em>)) + 1
- </p>
-
- <p>
- The maximum number of rows of direct blocks, <em>max_dblock_rows</em>,
- in any indirect block of a fractal heap is given by the
- following expression:
- <br /> <br />
- <em>max_dblock_rows</em> =
- (log<sub>2</sub>(<em>&lt;Max. Direct Block Size&gt;</em>) -
- log<sub>2</sub>(<em>&lt;Starting Block Size&gt;</em>)) + 2
- </p>
-
- <p>
- Using the computed values for <em>nrows</em> and
- <em>max_dblock_rows</em>, along with the <em>Width</em> of the
- doubling table, the number of direct and indirect block entries
- (<em>K</em> and <em>N</em> in the indirect block description, below)
- in an indirect block can be computed:
- <br /> <br />
- <em>K</em> = MIN(<em>nrows</em>, <em>max_dblock_rows</em>) *
- <em>Width</em>
-
- <br /> <br />
- If <em>nrows</em> is less than or equal to <em>max_dblock_rows</em>,
- <em>N</em> is 0. Otherwise, <em>N</em> is simply computed:
- <br /> <br />
- <em>N</em> = <em>K</em> - (<em>max_dblock_rows</em> *
- <em>Width</em>)
- </p>
-
- <p>
- The size indirect blocks on disk is determined by the number
- of rows in the indirect block (computed above). The size of direct
- blocks on disk is exactly the size of the block in the doubling
- table.
- </p>
-
- <div align="center">
- <table class="format">
- <caption>
- Fractal Heap Header
- </caption>
+ </table>
+</div>
+
+
+<br />
+<h3>
+ <a name="FractalHeap"> III.F. Disk Format: Level 1F - Fractal Heap</a>
+</h3>
+
+<p>
+ Each fractal heap consists of a header and zero or more direct and
+ indirect blocks (described below). The header contains general
+ information as well as initialization parameters for the doubling
+ table. The <em>Root Block Address</em> in the header points to the
+ first direct or indirect block in the heap.
+</p>
+
+<p>
+ Fractal heaps are based on a data structure called a <em>doubling
+ table</em>. A doubling table provides a mechanism for quickly extending an
+ array-like data structure that minimizes the number of empty blocks in
+ the heap, while retaining very fast lookup of any element within the
+ array. More information on fractal heaps and doubling tables can be
+ found in the RFC &ldquo;<a
+ href="Supplements/FractalHeap/PrivateHeap.pdf">Private Heaps in
+ HDF5</a>.&rdquo;
+</p>
+
+<p>The fractal heap implements the doubling table structure with
+ indirect and direct blocks. Indirect blocks in the heap do not actually
+ contain data for objects in the heap, their &ldquo;size&rdquo; is
+ abstract - they represent the indexing structure for locating the
+ direct blocks in the doubling table. Direct blocks contain the actual
+ data for objects stored in the heap.</p>
+
+<p>
+ All indirect blocks have a constant number of block entries in each
+ row, called the <em>width</em> of the doubling table (stored in the
+ heap header). The number of rows for each indirect block in the heap is
+ determined by the size of the block that the indirect block represents
+ in the doubling table (calculation of this is shown below) and is
+ constant, except for the &ldquo;root&rdquo; indirect block, which
+ expands and shrinks its number of rows as needed.
+</p>
+
+<p>
+ Blocks in the first <em>two</em> rows of an indirect block are <em>Starting
+ Block Size</em> number of bytes in size, and the blocks in each subsequent
+ row are twice the size of the blocks in the previous row. In other
+ words, blocks in the third row are twice the <em>Starting Block
+ Size</em>, blocks in the fourth row are four times the <em>Starting
+ Block Size</em>, and so on. Entries for blocks up to the <em>Maximum
+ Direct Block Size</em> point to direct blocks, and entries for blocks
+ greater than that size point to further indirect blocks (which have
+ their own entries for direct and indirect blocks).
+</p>
+
+<p>
+ The number of rows of blocks, <em>nrows</em>, in an indirect block of
+ size <em>iblock_size</em> is given by the following expression: <br />
+ <br /> <em>nrows</em> = (log<sub>2</sub>(<em>iblock_size</em>) - log<sub>2</sub>(<em>&lt;Starting
+ Block Size&gt;</em> * <em>&lt;Width&gt;</em>)) + 1
+</p>
+
+<p>
+ The maximum number of rows of direct blocks, <em>max_dblock_rows</em>,
+ in any indirect block of a fractal heap is given by the following
+ expression: <br /> <br /> <em>max_dblock_rows</em> = (log<sub>2</sub>(<em>&lt;Max.
+ Direct Block Size&gt;</em>) - log<sub>2</sub>(<em>&lt;Starting Block
+ Size&gt;</em>)) + 2
+</p>
+
+<p>
+ Using the computed values for <em>nrows</em> and <em>max_dblock_rows</em>,
+ along with the <em>Width</em> of the doubling table, the number of
+ direct and indirect block entries (<em>K</em> and <em>N</em> in the
+ indirect block description, below) in an indirect block can be
+ computed: <br /> <br /> <em>K</em> = MIN(<em>nrows</em>, <em>max_dblock_rows</em>)
+ * <em>Width</em> <br /> <br /> If <em>nrows</em> is less than or
+ equal to <em>max_dblock_rows</em>, <em>N</em> is 0. Otherwise, <em>N</em>
+ is simply computed: <br /> <br /> <em>N</em> = <em>K</em> - (<em>max_dblock_rows</em>
+ * <em>Width</em>)
+</p>
+
+<p>The size indirect blocks on disk is determined by the number of
+ rows in the indirect block (computed above). The size of direct blocks
+ on disk is exactly the size of the block in the doubling table.</p>
+
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap Header</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td colspan="4">Signature</td>
</tr>
<tr>
- <td>Version</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td>Version</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="2">Heap ID Length</td>
- <td colspan="2">I/O Filters&rsquo; Encoded Length</td>
+ <td colspan="2">Heap ID Length</td>
+ <td colspan="2">I/O Filters&rsquo; Encoded Length</td>
</tr>
<tr>
- <td>Flags</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td>Flags</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4">Maximum Size of Managed Objects</td>
+ <td colspan="4">Maximum Size of Managed Objects</td>
</tr>
<tr>
- <td colspan="4"><br />Next Huge Object ID<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Next Huge Object ID<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />v2 B-tree Address of Huge Objects<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />v2 B-tree Address of Huge Objects<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Amount of Free Space in Managed Blocks<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Amount of Free Space in Managed Blocks<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Address of Managed Block Free Space Manager<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Address of Managed Block Free Space
+ Manager<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Amount of Managed Space in Heap<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Amount of Managed Space in Heap<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Amount of Allocated Managed Space in Heap<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Amount of Allocated Managed Space in Heap<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Offset of Direct Block Allocation Iterator in Managed Space<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Offset of Direct Block Allocation
+ Iterator in Managed Space<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Number of Managed Objects in Heap<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Number of Managed Objects in Heap<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Size of Huge Objects in Heap<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Size of Huge Objects in Heap<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Number of Huge Objects in Heap<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Number of Huge Objects in Heap<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Size of Tiny Objects in Heap<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Size of Tiny Objects in Heap<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Number of Tiny Objects in Heap<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Number of Tiny Objects in Heap<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="2">Table Width</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td colspan="2">Table Width</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4"><br />Starting Block Size<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Starting Block Size<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Maximum Direct Block Size<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Maximum Direct Block Size<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="2">Maximum Heap Size</td>
- <td colspan="2">Starting # of Rows in Root Indirect Block</td>
+ <td colspan="2">Maximum Heap Size</td>
+ <td colspan="2">Starting # of Rows in Root Indirect Block</td>
</tr>
<tr>
- <td colspan="4"><br />Address of Root Block<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Address of Root Block<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="2">Current # of Rows in Root Indirect Block</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td colspan="2">Current # of Rows in Root Indirect Block</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4"><br />Size of Filtered Root Direct Block <em>(optional)</em><sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Size of Filtered Root Direct Block <em>(optional)</em><sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4">I/O Filter Mask<em> (optional)</em></td>
+ <td colspan="4">I/O Filter Mask<em> (optional)</em></td>
</tr>
<tr>
- <td colspan="4">I/O Filter Information<em> (optional, variable size)</em></td>
+ <td colspan="4">I/O Filter Information<em> (optional,
+ variable size)</em></td>
</tr>
<tr>
- <td colspan="4">Checksum</td>
+ <td colspan="4">Checksum</td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="40%">Field Name</th>
- <th>Description</th>
+ <th width="40%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>FRHP</code>&rdquo;
- is used to indicate the
- beginning of a fractal heap header. This gives file consistency
- checking utilities a better chance of reconstructing a
- damaged file.
- </p>
- </td>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>FRHP</code>
+ &rdquo; is used to indicate the beginning of a fractal heap header.
+ This gives file consistency checking utilities a better chance of
+ reconstructing a damaged file.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Version</p></td>
- <td>
- <p>This document describes version 0.</p>
- </td>
+ <td><p>Version</p></td>
+ <td>
+ <p>This document describes version 0.</p>
+ </td>
</tr>
<tr>
- <td><p>Heap ID Length</p></td>
- <td>
- <p>This is the length in bytes of heap object IDs for this heap.</p>
- </td>
+ <td><p>Heap ID Length</p></td>
+ <td>
+ <p>This is the length in bytes of heap object IDs for this heap.</p>
+ </td>
</tr>
<tr>
- <td><p>I/O Filters&rsquo; Encoded Length</p></td>
- <td>
- <p>This is the size in bytes of the encoded <em>I/O Filter Information</em>.
- </p>
- </td>
+ <td><p>I/O Filters&rsquo; Encoded Length</p></td>
+ <td>
+ <p>
+ This is the size in bytes of the encoded <em>I/O Filter
+ Information</em>.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Flags</p></td>
- <td>
- <p>This field is the heap status flag and is a bit field
- indicating additional information about the fractal heap.
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit(s)</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>If set, the ID value to use for huge object has wrapped
- around. If the value for the <em>Next Huge Object ID</em>
- has wrapped around, each new huge object inserted into the
- heap will require a search for an ID value.
- </td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td>If set, the direct blocks in the heap are checksummed.
- </td>
- </tr>
- <tr>
- <td align="center"><code>2-7</code></td>
- <td>Reserved</td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>Maximum Size of Managed Objects</p></td>
- <td>
- <p>This is the maximum size of managed objects allowed in the heap.
- Objects greater than this this are &lsquo;huge&rsquo; objects and will be
- stored in the file directly, rather than in a direct block for
- the heap.
- </p>
- </td>
+ <td><p>Flags</p></td>
+ <td>
+ <p>This field is the heap status flag and is a bit field
+ indicating additional information about the fractal heap.</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit(s)</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>If set, the ID value to use for huge object has wrapped
+ around. If the value for the <em>Next Huge Object ID</em> has
+ wrapped around, each new huge object inserted into the heap will
+ require a search for an ID value.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>If set, the direct blocks in the heap are checksummed.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>2-7</code></td>
+ <td>Reserved</td>
+ </tr>
+ </table>
+ <p></p>
+
+ </td>
</tr>
<tr>
- <td><p>Next Huge Object ID</p></td>
- <td>
- <p>This is the next ID value to use for a huge object in the heap.
- </p>
- </td>
+ <td><p>Maximum Size of Managed Objects</p></td>
+ <td>
+ <p>This is the maximum size of managed objects allowed in the
+ heap. Objects greater than this this are &lsquo;huge&rsquo; objects
+ and will be stored in the file directly, rather than in a direct
+ block for the heap.</p>
+ </td>
</tr>
<tr>
- <td><p>v2 B-tree Address of Huge Objects</p></td>
- <td>
- <p>This is the address of the <a href="#V2Btrees">v2 B-tree</a>
- used to track huge objects in the heap. The type of records
- stored in the <em>v2 B-tree</em> will
- be determined by whether the address & length of a huge object
- can fit into a heap ID (if yes, it is a &ldquo;directly&rdquo; accessed
- huge object) and whether there is a filter used on objects
- in the heap.
- </p>
- </td>
+ <td><p>Next Huge Object ID</p></td>
+ <td>
+ <p>This is the next ID value to use for a huge object in the
+ heap.</p>
+ </td>
</tr>
<tr>
- <td><p>Amount of Free Space in Managed Blocks</p></td>
- <td>
- <p>This is the total amount of free space in managed direct blocks
- (in bytes).
- </p>
- </td>
+ <td><p>v2 B-tree Address of Huge Objects</p></td>
+ <td>
+ <p>
+ This is the address of the <a href="#V2Btrees">v2 B-tree</a> used
+ to track huge objects in the heap. The type of records stored in
+ the <em>v2 B-tree</em> will be determined by whether the address &
+ length of a huge object can fit into a heap ID (if yes, it is a
+ &ldquo;directly&rdquo; accessed huge object) and whether there is a
+ filter used on objects in the heap.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Address of Managed Block Free Space Manager</p></td>
- <td>
- <p>This is the address of the
- <em><a href="#FreeSpaceManager">Free-space Manager</a></em> for
- managed blocks.
- </p>
- </td>
+ <td><p>Amount of Free Space in Managed Blocks</p></td>
+ <td>
+ <p>This is the total amount of free space in managed direct
+ blocks (in bytes).</p>
+ </td>
</tr>
<tr>
- <td><p>Amount of Managed Space in Heap</p></td>
- <td>
- <p>This is the total amount of managed space in the heap (in bytes),
- essentially the upper bound of the heap&rsquo;s linear address space.
- </p>
- </td>
+ <td><p>Address of Managed Block Free Space Manager</p></td>
+ <td>
+ <p>
+ This is the address of the <em><a href="#FreeSpaceManager">Free-space
+ Manager</a></em> for managed blocks.
+ </p>
+ </td>
</tr>
- <tr>
- <td><p>Amount of Allocated Managed Space in Heap</p></td>
- <td>
- <p>This is the total amount of managed space (in bytes) actually
- allocated in
- the heap. This can be less than the <em>Amount of Managed Space
- in Heap</em> field, if some direct blocks in the heap&rsquo;s linear
- address space are not allocated.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Offset of Direct Block Allocation Iterator in Managed Space</p></td>
- <td>
- <p>This is the linear heap offset where the next direct
- block should be allocated at (in bytes). This may be less than
- the <em>Amount of Managed Space in Heap</em> value because the
- heap&rsquo;s address space is increased by a &ldquo;row&rdquo; of direct blocks
- at a time, rather than by single direct block increments.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Number of Managed Objects in Heap</p></td>
- <td>
- <p>This is the number of managed objects in the heap.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Size of Huge Objects in Heap</p></td>
- <td>
- <p>This is the total size of huge objects in the heap (in bytes).
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Number of Huge Objects in Heap</p></td>
- <td>
- <p>This is the number of huge objects in the heap.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Size of Tiny Objects in Heap</p></td>
- <td>
- <p>This is the total size of tiny objects that are packed in heap
- IDs (in bytes).
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Number of Tiny Objects in Heap</p></td>
- <td>
- <p>This is the number of tiny objects that are packed in heap IDs.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Table Width</p></td>
- <td>
- <p>This is the number of columns in the doubling table for managed
- blocks. This value must be a power of two.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Starting Block Size</p></td>
- <td>
- <p>This is the starting block size to use in the doubling table for
- managed blocks (in bytes). This value must be a power of two.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Maximum Direct Block Size</p></td>
- <td>
- <p>This is the maximum size allowed for a managed direct block.
- Objects inserted into the heap that are larger than this value
- (less the # of bytes of direct block prefix/suffix)
- are stored as &lsquo;huge&rsquo; objects. This value must be a power of
- two.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Maximum Heap Size</p></td>
- <td>
- <p>This is the maximum size of the heap&rsquo;s linear address space for
- managed objects (in bytes). The value stored is the log2 of
- the actual value, that is: the # of bits of the address space.
- &lsquo;Huge&rsquo; and &lsquo;tiny&rsquo; objects are not counted in this value, since
- they do not store objects in the linear address space of the
- heap.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Starting # of Rows in Root Indirect Block</p></td>
- <td>
- <p>This is the starting number of rows for the root indirect block.
- A value of 0 indicates that the root indirect block will have
- the maximum number of rows needed to address the heap&rsquo;s <em>Maximum
- Heap Size</em>.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Address of Root Block</p></td>
- <td>
- <p>This is the address of the root block for the heap. It can
- be the <a href="#UndefinedAddress">undefined address</a> if
- there is no data in the heap. It either points to a direct
- block (if the <em>Current # of Rows in the Root Indirect Block</em>
- value is 0), or an indirect block.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Current # of Rows in Root Indirect Block</p></td>
- <td>
- <p>This is the current number of rows in the root indirect block.
- A value of 0 indicates that <em>Address of Root Block</em>
- points to direct block instead of indirect block.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Size of Filtered Root Direct Block</p></td>
- <td>
- <p>This is the size of the root direct block, if filters are
- applied to heap objects (in bytes). This field is only
- stored in the header if the <em>I/O Filters&rsquo; Encoded Length</em>
- is greater than 0.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>I/O Filter Mask</p></td>
- <td>
- <p>This is the filter mask for the root direct block, if filters
- are applied to heap objects. This mask has the same format as
- that used for the filter mask in chunked raw data records in a
- <a href="#V1Btrees">v1 B-tree</a>.
- This field is only
- stored in the header if the <em>I/O Filters&rsquo; Encoded Length</em>
- is greater than 0.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>I/O Filter Information</p></td>
- <td>
- <p>This is the I/O filter information encoding direct blocks and
- huge objects, if filters are applied to heap objects. This
- field is encoded as a <a href="#FilterMessage">Filter Pipeline</a>
- message.
- The size of this field is determined by <em>I/O Filters&rsquo;
- Encoded Length</em>.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Checksum</p></td>
- <td>
- <p>This is the checksum for the header.</p>
- </td>
+ <tr>
+ <td><p>Amount of Managed Space in Heap</p></td>
+ <td>
+ <p>This is the total amount of managed space in the heap (in
+ bytes), essentially the upper bound of the heap&rsquo;s linear
+ address space.</p>
+ </td>
</tr>
- </table>
- </div>
+ <tr>
+ <td><p>Amount of Allocated Managed Space in Heap</p></td>
+ <td>
+ <p>
+ This is the total amount of managed space (in bytes) actually
+ allocated in the heap. This can be less than the <em>Amount of
+ Managed Space in Heap</em> field, if some direct blocks in the
+ heap&rsquo;s linear address space are not allocated.
+ </p>
+ </td>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Fractal Heap Direct Block
- </caption>
+ <tr>
+ <td><p>Offset of Direct Block Allocation Iterator in Managed
+ Space</p></td>
+ <td>
+ <p>
+ This is the linear heap offset where the next direct block should
+ be allocated at (in bytes). This may be less than the <em>Amount
+ of Managed Space in Heap</em> value because the heap&rsquo;s address
+ space is increased by a &ldquo;row&rdquo; of direct blocks at a
+ time, rather than by single direct block increments.
+ </p>
+ </td>
+ </tr>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <td><p>Number of Managed Objects in Heap</p></td>
+ <td>
+ <p>This is the number of managed objects in the heap.</p>
+ </td>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td><p>Size of Huge Objects in Heap</p></td>
+ <td>
+ <p>This is the total size of huge objects in the heap (in
+ bytes).</p>
+ </td>
</tr>
<tr>
- <td>Version</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td><p>Number of Huge Objects in Heap</p></td>
+ <td>
+ <p>This is the number of huge objects in the heap.</p>
+ </td>
</tr>
<tr>
- <td colspan="4"><br />Heap Header Address<sup>O</sup><br /><br /></td>
+ <td><p>Size of Tiny Objects in Heap</p></td>
+ <td>
+ <p>This is the total size of tiny objects that are packed in
+ heap IDs (in bytes).</p>
+ </td>
</tr>
<tr>
- <td colspan="4">Block Offset <em>(variable size)</em></td>
+ <td><p>Number of Tiny Objects in Heap</p></td>
+ <td>
+ <p>This is the number of tiny objects that are packed in heap
+ IDs.</p>
+ </td>
</tr>
<tr>
- <td colspan="4">Checksum <em>(optional)</em></td>
+ <td><p>Table Width</p></td>
+ <td>
+ <p>This is the number of columns in the doubling table for
+ managed blocks. This value must be a power of two.</p>
+ </td>
</tr>
<tr>
- <td colspan="4"><br />Object Data <em>(variable size)</em><br /><br /></td>
+ <td><p>Starting Block Size</p></td>
+ <td>
+ <p>This is the starting block size to use in the doubling table
+ for managed blocks (in bytes). This value must be a power of two.</p>
+ </td>
</tr>
- </table>
+ <tr>
+ <td><p>Maximum Direct Block Size</p></td>
+ <td>
+ <p>This is the maximum size allowed for a managed direct block.
+ Objects inserted into the heap that are larger than this value
+ (less the # of bytes of direct block prefix/suffix) are stored as
+ &lsquo;huge&rsquo; objects. This value must be a power of two.</p>
+ </td>
+ </tr>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td><p>Maximum Heap Size</p></td>
+ <td>
+ <p>This is the maximum size of the heap&rsquo;s linear address
+ space for managed objects (in bytes). The value stored is the log2
+ of the actual value, that is: the # of bits of the address space.
+ &lsquo;Huge&rsquo; and &lsquo;tiny&rsquo; objects are not counted
+ in this value, since they do not store objects in the linear
+ address space of the heap.</p>
+ </td>
+ </tr>
- </div>
+ <tr>
+ <td><p>Starting # of Rows in Root Indirect Block</p></td>
+ <td>
+ <p>
+ This is the starting number of rows for the root indirect block. A
+ value of 0 indicates that the root indirect block will have the
+ maximum number of rows needed to address the heap&rsquo;s <em>Maximum
+ Heap Size</em>.
+ </p>
+ </td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <tr>
+ <td><p>Address of Root Block</p></td>
+ <td>
+ <p>
+ This is the address of the root block for the heap. It can be the <a
+ href="#UndefinedAddress">undefined address</a> if there is no data
+ in the heap. It either points to a direct block (if the <em>Current
+ # of Rows in the Root Indirect Block</em> value is 0), or an indirect
+ block.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>FHDB</code>&rdquo;
- is used to indicate the
- beginning of a fractal heap direct block. This gives file consistency
- checking utilities a better chance of reconstructing a
- damaged file.
- </p>
- </td>
+ <td><p>Current # of Rows in Root Indirect Block</p></td>
+ <td>
+ <p>
+ This is the current number of rows in the root indirect block. A
+ value of 0 indicates that <em>Address of Root Block</em> points to
+ direct block instead of indirect block.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Size of Filtered Root Direct Block</p></td>
+ <td>
+ <p>
+ This is the size of the root direct block, if filters are applied
+ to heap objects (in bytes). This field is only stored in the header
+ if the <em>I/O Filters&rsquo; Encoded Length</em> is greater than
+ 0.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Version</p></td>
- <td>
- <p>This document describes version 0.</p>
- </td>
+ <td><p>I/O Filter Mask</p></td>
+ <td>
+ <p>
+ This is the filter mask for the root direct block, if filters are
+ applied to heap objects. This mask has the same format as that used
+ for the filter mask in chunked raw data records in a <a
+ href="#V1Btrees">v1 B-tree</a>. This field is only stored in the
+ header if the <em>I/O Filters&rsquo; Encoded Length</em> is greater
+ than 0.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Heap Header Address</p></td>
- <td>
- <p>This is the address for the fractal heap header that this
- block belongs to. This field is principally used for file
- integrity checking.
- </p>
- </td>
+ <td><p>I/O Filter Information</p></td>
+ <td>
+ <p>
+ This is the I/O filter information encoding direct blocks and huge
+ objects, if filters are applied to heap objects. This field is
+ encoded as a <a href="#FilterMessage">Filter Pipeline</a> message.
+ The size of this field is determined by <em>I/O Filters&rsquo;
+ Encoded Length</em>.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Block Offset</p></td>
- <td>
- <p>This is the offset of the block within the fractal heap&rsquo;s
- address space (in bytes). The number of bytes used to encode
- this field is the <em>Maximum Heap Size</em> (in the heap&rsquo;s
- header) divided by 8 and rounded up to the next highest integer,
- for values that are not a multiple of 8. This value is
- principally used for file integrity checking.
- </p>
- </td>
+ <td><p>Checksum</p></td>
+ <td>
+ <p>This is the checksum for the header.</p>
+ </td>
</tr>
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap Direct Block</caption>
+
<tr>
- <td><p>Checksum</p></td>
- <td>
- <p>This is the checksum for the direct block.</p>
- <p>This field is only present if bit 1 of <em>Flags</em> in the
- heap&rsquo;s header is set.</p>
- </td>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td><p>Object Data</p></td>
- <td>
- <p>This section of the direct block stores the actual data for
- objects in the heap. The size of this section is determined by
- the direct block&rsquo;s size minus the size of the other fields
- stored in the direct block (for example, the <em>Signature</em>,
- <em>Version</em>, and others including the <em>Checksum</em> if it is
- present).
- </p>
- </td>
+ <td colspan="4">Signature</td>
</tr>
- </table>
- </div>
+ <tr>
+ <td>Version</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Fractal Heap Indirect Block
- </caption>
+ <tr>
+ <td colspan="4"><br />Heap Header Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <td colspan="4">Block Offset <em>(variable size)</em></td>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td colspan="4">Checksum <em>(optional)</em></td>
</tr>
<tr>
- <td>Version</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td colspan="4"><br />Object Data <em>(variable size)</em><br />
+ <br /></td>
</tr>
+ </table>
+
+ <table class="note">
<tr>
- <td colspan="4"><br />Heap Header Address<sup>O</sup><br /><br /></td>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
</tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <td colspan="4">Block Offset <em>(variable size)</em></td>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td colspan="4"><br />Child Direct Block #0 Address<sup>O</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Size of Filtered Direct Block #0 <em>(optional)</em> <sup>L</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4">Filter Mask for Direct Block #0 <em>(optional)</em></td>
- </tr>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>FHDB</code>
+ &rdquo; is used to indicate the beginning of a fractal heap direct
+ block. This gives file consistency checking utilities a better
+ chance of reconstructing a damaged file.
+ </p>
+ </td>
+ </tr>
<tr>
- <td colspan="4"><br />Child Direct Block #1 Address<sup>O</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Size of Filtered Direct Block #1 <em>(optional)</em><sup>L</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4">Filter Mask for Direct Block #1 <em>(optional)</em></td>
- </tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>This document describes version 0.</p>
+ </td>
+ </tr>
- <tr>
- <td colspan="4">...</td>
- </tr>
+ <tr>
+ <td><p>Heap Header Address</p></td>
+ <td>
+ <p>This is the address for the fractal heap header that this
+ block belongs to. This field is principally used for file integrity
+ checking.</p>
+ </td>
+ </tr>
<tr>
- <td colspan="4"><br />Child Direct Block #K-1 Address<sup>O</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Size of Filtered Direct Block #K-1 <em>(optional)</em><sup>L</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4">Filter Mask for Direct Block #K-1 <em>(optional)</em></td>
- </tr>
+ <td><p>Block Offset</p></td>
+ <td>
+ <p>
+ This is the offset of the block within the fractal heap&rsquo;s
+ address space (in bytes). The number of bytes used to encode this
+ field is the <em>Maximum Heap Size</em> (in the heap&rsquo;s
+ header) divided by 8 and rounded up to the next highest integer,
+ for values that are not a multiple of 8. This value is principally
+ used for file integrity checking.
+ </p>
+ </td>
+ </tr>
<tr>
- <td colspan="4"><br />Child Indirect Block #0 Address<sup>O</sup><br /><br /></td>
- </tr>
+ <td><p>Checksum</p></td>
+ <td>
+ <p>This is the checksum for the direct block.</p>
+ <p>
+ This field is only present if bit 1 of <em>Flags</em> in the
+ heap&rsquo;s header is set.
+ </p>
+ </td>
+ </tr>
<tr>
- <td colspan="4"><br />Child Indirect Block #1 Address<sup>O</sup><br /><br /></td>
- </tr>
+ <td><p>Object Data</p></td>
+ <td>
+ <p>
+ This section of the direct block stores the actual data for objects
+ in the heap. The size of this section is determined by the direct
+ block&rsquo;s size minus the size of the other fields stored in the
+ direct block (for example, the <em>Signature</em>, <em>Version</em>,
+ and others including the <em>Checksum</em> if it is present).
+ </p>
+ </td>
+ </tr>
- <tr>
- <td colspan="4">...</td>
- </tr>
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap Indirect Block</caption>
<tr>
- <td colspan="4"><br />Child Indirect Block #N-1 Address<sup>O</sup><br /><br /></td>
- </tr>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ </tr>
<tr>
- <td colspan="4">Checksum</td>
+ <td colspan="4">Signature</td>
</tr>
- </table>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <td>Version</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td colspan="4"><br />Heap Header Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
- </div>
+ <tr>
+ <td colspan="4">Block Offset <em>(variable size)</em></td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <tr>
+ <td colspan="4"><br />Child Direct Block #0 Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Size of Filtered Direct Block #0 <em>(optional)</em>
+ <sup>L</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4">Filter Mask for Direct Block #0 <em>(optional)</em></td>
</tr>
<tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>FHIB</code>&rdquo; is used to
- indicate the beginning of a fractal heap indirect block. This
- gives file consistency checking utilities a better chance of
- reconstructing a damaged file.
- </p>
- </td>
+ <td colspan="4"><br />Child Direct Block #1 Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Size of Filtered Direct Block #1 <em>(optional)</em><sup>L</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4">Filter Mask for Direct Block #1 <em>(optional)</em></td>
</tr>
<tr>
- <td><p>Version</p></td>
- <td>
- <p>This document describes version 0.</p>
- </td>
+ <td colspan="4">...</td>
</tr>
<tr>
- <td><p>Heap Header Address</p></td>
- <td>
- <p>This is the address for the fractal heap header that this
- block belongs to. This field is principally used for file
- integrity checking.
- </p>
- </td>
+ <td colspan="4"><br />Child Direct Block #K-1 Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Size of Filtered Direct Block #K-1 <em>(optional)</em><sup>L</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4">Filter Mask for Direct Block #K-1 <em>(optional)</em></td>
</tr>
<tr>
- <td><p>Block Offset</p></td>
- <td>
- <p>This is the offset of the block within the fractal heap&rsquo;s
- address space (in bytes). The number of bytes used to encode
- this field is the <em>Maximum Heap Size</em> (in the heap&rsquo;s
- header) divided by 8 and rounded up to the next highest integer,
- for values that are not a multiple of 8. This value is
- principally used for file integrity checking.
- </p>
- </td>
+ <td colspan="4"><br />Child Indirect Block #0 Address<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td><p>Child Direct Block #K Address</p></td>
- <td>
- <p>This field is the address of the child direct block.
- The size of the [uncompressed] direct block can be computed by
- its offset in the heap&rsquo;s linear address space.
- </p>
- </td>
+ <td colspan="4"><br />Child Indirect Block #1 Address<sup>O</sup><br />
+ <br /></td>
</tr>
- <tr>
- <td><p>Size of Filtered Direct Block #K</p></td>
- <td>
- <p>This is the size of the child direct block after passing through
- the I/O filters defined for this heap (in bytes). If no I/O
- filters are present for this heap, this field is not present.
- </p>
- </td>
- </tr>
- <tr>
- <td><p>Filter Mask for Direct Block #K</p></td>
- <td>
- <p>This is the I/O filter mask for the filtered direct block.
- This mask has the same format as that used for the filter mask
- in chunked raw data records in a <a href="#V1Btrees">v1 B-tree</a>.
- If no I/O filters are present for this heap, this field is not
- present.
- </p>
- </td>
+ <tr>
+ <td colspan="4">...</td>
</tr>
<tr>
- <td><p>Child Indirect Block #N Address</p></td>
- <td>
- <p>This field is the address of the child indirect block.
- The size of the indirect block can be computed by
- its offset in the heap&rsquo;s linear address space.
- </p>
- </td>
+ <td colspan="4"><br />Child Indirect Block #N-1 Address<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td><p>Checksum</p></td>
- <td>
- <p>This is the checksum for the indirect block.</p>
- </td>
+ <td colspan="4">Checksum</td>
</tr>
+ </table>
- </table>
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ <tr>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <p>An object in the fractal heap is identified by means of a fractal heap ID,
- which encodes information to locate the object in the heap.
- Currently, the fractal heap stores an object in one of three ways,
- depending on the object&rsquo;s size:</p>
-
- <div align="center">
- <table class="list80">
- <tr>
- <th width="20%">Type</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center">Tiny</td>
- <td>
- <p>When an object is small enough to be encoded in the heap ID, the
- object&rsquo;s data is embedded in the fractal heap ID itself. There are
- 2 sub-types for this type of object: normal and extended. The
- sub-type for tiny heap IDs depends on whether the heap ID is large
- enough to store objects greater than 16 bytes or not. If the
- heap ID length is 18 bytes or smaller, the &lsquo;normal&rsquo; tiny heap ID
- form is used. If the heap ID length is greater than 18 bytes in
- length, the &ldquo;extended&rdquo; form is used. See format description below
- for both sub-types.
- </p>
- </td>
- </tr>
-
- <tr>
- <td align="center">Huge</td>
- <td>
- <p>When the size of an object is larger than <em>Maximum Size of
- Managed Objects</em> in the <em>Fractal Heap Header</em>, the
- object&rsquo;s data is stored on its own in the file and the object
- is tracked/indexed via a version 2 B-tree. All huge objects
- for a particular fractal heap use the same v2 B-tree. All huge
- objects for a particular fractal heap use the same format for
- their huge object IDs.
- </p>
-
- <p>Depending on whether the IDs for a heap are large enough to hold
- the object&rsquo;s retrieval information and whether I/O pipeline filters
- are applied to the heap&rsquo;s objects, 4 sub-types are derived for
- huge object IDs for this heap:</p>
-
- <div align="center">
- <table class="list">
- <tr>
- <th align="left" width="35%">Sub-type</th>
- <th align="left">Description</th>
- </tr>
-
- <tr>
- <td align="left">Directly accessed, non-filtered</td>
- <td>
- <p>The object&rsquo;s address and length are embedded in the
- fractal heap ID itself and the object is directly accessed
- from them. This allows the object to be accessed without
- resorting to the B-tree.
- </p>
- </td>
- </tr>
-
- <tr>
- <td align="left">Directly accessed, filtered</td>
- <td>
- <p>The filtered object&rsquo;s address, length, filter mask and
- de-filtered size are embedded in the fractal heap ID itself
- and the object is accessed directly with them. This allows
- the object to be accessed without resorting to the B-tree.
- </p>
- </td>
- </tr>
-
- <tr>
- <td align="left">Indirectly accessed, non-filtered</td>
- <td>
- <p>The object is located by using a B-tree key embedded in
- the fractal heap ID to retrieve the address and length from
- the version 2 B-tree for huge objects. Then, the address
- and length are used to access the object.
- </p>
- </td>
- </tr>
-
- <tr>
- <td align="left">Indirectly accessed, filtered</td>
- <td>
- <p>The object is located by using a B-tree key embedded in
- the fractal heap ID to retrieve the filtered object&rsquo;s
- address, length, filter mask and de-filtered size from the
- version 2 B-tree for huge objects. Then, this information
- is used to access the object.
- </p>
- </td>
- </tr>
- </table>
- </div>
-
- </td>
- </tr>
-
- <tr>
- <td align="center">Managed</td>
- <td>
- <p>When the size of an object does not meet the above two
- conditions, the object is stored and managed via the direct and
- indirect blocks based on the doubling table.
- </p>
- </td>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
- </table>
- </div>
+ <tr>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>FHIB</code>
+ &rdquo; is used to indicate the beginning of a fractal heap
+ indirect block. This gives file consistency checking utilities a
+ better chance of reconstructing a damaged file.
+ </p>
+ </td>
+ </tr>
- <p>The specific format for each type of heap ID is described below:
- </p>
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>This document describes version 0.</p>
+ </td>
+ </tr>
- <div align="center">
- <table class="format">
- <caption>Fractal Heap ID for Tiny Objects (sub-type 1 - &lsquo;Normal&rsquo;)
- </caption>
+ <tr>
+ <td><p>Heap Header Address</p></td>
+ <td>
+ <p>This is the address for the fractal heap header that this
+ block belongs to. This field is principally used for file integrity
+ checking.</p>
+ </td>
+ </tr>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
+ <td><p>Block Offset</p></td>
+ <td>
+ <p>
+ This is the offset of the block within the fractal heap&rsquo;s
+ address space (in bytes). The number of bytes used to encode this
+ field is the <em>Maximum Heap Size</em> (in the heap&rsquo;s
+ header) divided by 8 and rounded up to the next highest integer,
+ for values that are not a multiple of 8. This value is principally
+ used for file integrity checking.
+ </p>
+ </td>
+ </tr>
<tr>
- <td>Version, Type & Length</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td><p>Child Direct Block #K Address</p></td>
+ <td>
+ <p>This field is the address of the child direct block. The size
+ of the [uncompressed] direct block can be computed by its offset in
+ the heap&rsquo;s linear address space.</p>
+ </td>
</tr>
<tr>
- <td colspan="4"><br />Data <em>(variable size)</em></td>
+ <td><p>Size of Filtered Direct Block #K</p></td>
+ <td>
+ <p>This is the size of the child direct block after passing
+ through the I/O filters defined for this heap (in bytes). If no I/O
+ filters are present for this heap, this field is not present.</p>
+ </td>
+ </tr>
+ <tr>
+ <td><p>Filter Mask for Direct Block #K</p></td>
+ <td>
+ <p>
+ This is the I/O filter mask for the filtered direct block. This
+ mask has the same format as that used for the filter mask in
+ chunked raw data records in a <a href="#V1Btrees">v1 B-tree</a>. If
+ no I/O filters are present for this heap, this field is not
+ present.
+ </p>
+ </td>
</tr>
- </table>
- </div>
+ <tr>
+ <td><p>Child Indirect Block #N Address</p></td>
+ <td>
+ <p>This field is the address of the child indirect block. The
+ size of the indirect block can be computed by its offset in the
+ heap&rsquo;s linear address space.</p>
+ </td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version, Type & Length</p></td>
- <td>
- <p>This is a bit field with the following definition:
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>6-7</code></td>
- <td>The current version of ID format. This document
- describes version 0.
- </td>
- </tr>
- <tr>
- <td align="center"><code>4-5</code></td>
- <td>The ID type. Tiny objects have a value of <code>2</code>.
- </td>
- </tr>
- <tr>
- <td align="center"><code>0-3</code></td>
- <td>The length of the tiny object. The value stored
- is one less than the actual length (since zero-length
- objects are not allowed to be stored in the heap).
- For example, an object of actual length 1 has an
- encoded length of 0, an object of actual length 2
- has an encoded length of 1, and so on.
- </td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>Data</p></td>
- <td>
- <p>This is the data for the object.
- </p>
- </td>
+ <tr>
+ <td><p>Checksum</p></td>
+ <td>
+ <p>This is the checksum for the indirect block.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>Fractal Heap ID for Tiny Objects (sub-type 2 - &lsquo;Extended&rsquo;)
- </caption>
+</div>
+
+<br />
+<p>An object in the fractal heap is identified by means of a fractal
+ heap ID, which encodes information to locate the object in the heap.
+ Currently, the fractal heap stores an object in one of three ways,
+ depending on the object&rsquo;s size:</p>
+
+<div align="center">
+ <table class="list80">
+ <tr>
+ <th width="20%">Type</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center">Tiny</td>
+ <td>
+ <p>When an object is small enough to be encoded in the heap ID,
+ the object&rsquo;s data is embedded in the fractal heap ID itself.
+ There are 2 sub-types for this type of object: normal and extended.
+ The sub-type for tiny heap IDs depends on whether the heap ID is
+ large enough to store objects greater than 16 bytes or not. If the
+ heap ID length is 18 bytes or smaller, the &lsquo;normal&rsquo;
+ tiny heap ID form is used. If the heap ID length is greater than 18
+ bytes in length, the &ldquo;extended&rdquo; form is used. See
+ format description below for both sub-types.</p>
+ </td>
+ </tr>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
+ <td align="center">Huge</td>
+ <td>
+ <p>
+ When the size of an object is larger than <em>Maximum Size of
+ Managed Objects</em> in the <em>Fractal Heap Header</em>, the
+ object&rsquo;s data is stored on its own in the file and the object
+ is tracked/indexed via a version 2 B-tree. All huge objects for a
+ particular fractal heap use the same v2 B-tree. All huge objects
+ for a particular fractal heap use the same format for their huge
+ object IDs.
+ </p>
+
+ <p>Depending on whether the IDs for a heap are large enough to
+ hold the object&rsquo;s retrieval information and whether I/O
+ pipeline filters are applied to the heap&rsquo;s objects, 4
+ sub-types are derived for huge object IDs for this heap:</p>
+
+ <div align="center">
+ <table class="list">
+ <tr>
+ <th align="left" width="35%">Sub-type</th>
+ <th align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="left">Directly accessed, non-filtered</td>
+ <td>
+ <p>The object&rsquo;s address and length are embedded in the
+ fractal heap ID itself and the object is directly accessed from
+ them. This allows the object to be accessed without resorting
+ to the B-tree.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td align="left">Directly accessed, filtered</td>
+ <td>
+ <p>The filtered object&rsquo;s address, length, filter mask
+ and de-filtered size are embedded in the fractal heap ID itself
+ and the object is accessed directly with them. This allows the
+ object to be accessed without resorting to the B-tree.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td align="left">Indirectly accessed, non-filtered</td>
+ <td>
+ <p>The object is located by using a B-tree key embedded in
+ the fractal heap ID to retrieve the address and length from the
+ version 2 B-tree for huge objects. Then, the address and length
+ are used to access the object.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td align="left">Indirectly accessed, filtered</td>
+ <td>
+ <p>The object is located by using a B-tree key embedded in
+ the fractal heap ID to retrieve the filtered object&rsquo;s
+ address, length, filter mask and de-filtered size from the
+ version 2 B-tree for huge objects. Then, this information is
+ used to access the object.</p>
+ </td>
+ </tr>
+ </table>
+ </div>
+
+ </td>
+ </tr>
<tr>
- <td>Version, Type & Length</td>
- <td>Extended Length</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td align="center">Managed</td>
+ <td>
+ <p>When the size of an object does not meet the above two
+ conditions, the object is stored and managed via the direct and
+ indirect blocks based on the doubling table.</p>
+ </td>
</tr>
+ </table>
+</div>
+
+
+<p>The specific format for each type of heap ID is described below:
+</p>
+
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap ID for Tiny Objects (sub-type 1 -
+ &lsquo;Normal&rsquo;)</caption>
<tr>
- <td colspan="4">Data <em>(variable size)</em></td>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
- </table>
- </div>
+ <tr>
+ <td>Version, Type & Length</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version, Type & Length</p></td>
- <td>
- <p>This is a bit field with the following definition:
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>6-7</code></td>
- <td>The current version of ID format. This document
- describes version 0.
- </td>
- </tr>
- <tr>
- <td align="center"><code>4-5</code></td>
- <td>The ID type. Tiny objects have a value of <code>2</code>.
- </td>
- </tr>
- <tr>
- <td align="center"><code>0-3</code></td>
- <td>These 4 bits, together with the next byte, form an
- unsigned 12-bit integer for holding the length of the
- object. These 4-bits are bits 8-11 of the 12-bit integer.
- See description for the <em>Extended Length</em> field below.
- </td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>Extended Length</p></td>
- <td>
- <p>This byte, together with the 4 bits in the previous byte,
- forms an unsigned 12-bit integer for holding the length of
- the tiny object. These 8 bits are bits 0-7 of the 12-bit
- integer formed. The value stored is one less than the actual
- length (since zero-length objects are not allowed to be
- stored in the heap). For example, an object of actual length
- 1 has an encoded length of 0, an object of actual length
- 2 has an encoded length of 1, and so on.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Data</p></td>
- <td>
- <p>This is the data for the object.
- </p>
- </td>
+ <tr>
+ <td colspan="4"><br />Data <em>(variable size)</em></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>Fractal Heap ID for Huge Objects (sub-type 1 & 2): indirectly accessed, non-filtered/filtered
- </caption>
+ <tr>
+ <td><p>Version, Type & Length</p></td>
+ <td>
+ <p>This is a bit field with the following definition:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>6-7</code></td>
+ <td>The current version of ID format. This document describes
+ version 0.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>4-5</code></td>
+ <td>The ID type. Tiny objects have a value of <code>2</code>.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>0-3</code></td>
+ <td>The length of the tiny object. The value stored is one
+ less than the actual length (since zero-length objects are not
+ allowed to be stored in the heap). For example, an object of
+ actual length 1 has an encoded length of 0, an object of actual
+ length 2 has an encoded length of 1, and so on.</td>
+ </tr>
+ </table>
+ <p></p>
+
+ </td>
+ </tr>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <td><p>Data</p></td>
+ <td>
+ <p>This is the data for the object.</p>
+ </td>
</tr>
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap ID for Tiny Objects (sub-type 2 -
+ &lsquo;Extended&rsquo;)</caption>
+
<tr>
- <td>Version & Type</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4"><br />v2 B-tree Key<sup>L</sup><em> (variable size)</em><br /><br /></td>
+ <td>Version, Type & Length</td>
+ <td>Extended Length</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
- </table>
+ <tr>
+ <td colspan="4">Data <em>(variable size)</em></td>
+ </tr>
+
+ </table>
+</div>
- <table class="note">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
- </div>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <td><p>Version, Type & Length</p></td>
+ <td>
+ <p>This is a bit field with the following definition:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>6-7</code></td>
+ <td>The current version of ID format. This document describes
+ version 0.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>4-5</code></td>
+ <td>The ID type. Tiny objects have a value of <code>2</code>.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>0-3</code></td>
+ <td>These 4 bits, together with the next byte, form an
+ unsigned 12-bit integer for holding the length of the object.
+ These 4-bits are bits 8-11 of the 12-bit integer. See description
+ for the <em>Extended Length</em> field below.
+ </td>
+ </tr>
+ </table>
+ <p></p>
+
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Extended Length</p></td>
+ <td>
+ <p>This byte, together with the 4 bits in the previous byte,
+ forms an unsigned 12-bit integer for holding the length of the tiny
+ object. These 8 bits are bits 0-7 of the 12-bit integer formed. The
+ value stored is one less than the actual length (since zero-length
+ objects are not allowed to be stored in the heap). For example, an
+ object of actual length 1 has an encoded length of 0, an object of
+ actual length 2 has an encoded length of 1, and so on.</p>
+ </td>
</tr>
<tr>
- <td><p>Version & Type</p></td>
- <td>
- <p>This is a bit field with the following definition:
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
+ <td><p>Data</p></td>
+ <td>
+ <p>This is the data for the object.</p>
+ </td>
+ </tr>
+
+ </table>
+</div>
- <tr>
- <td align="center"><code>6-7</code></td>
- <td>The current version of ID format. This document
- describes version 0.
- </td>
- </tr>
- <tr>
- <td align="center"><code>4-5</code></td>
- <td>The ID type. Huge objects have a value of <code>1</code>.
- </td>
- </tr>
- <tr>
- <td align="center"><code>0-3</code></td>
- <td>Reserved.
- </td>
- </tr>
- </table></p>
- </td>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap ID for Huge Objects (sub-type 1 & 2):
+ indirectly accessed, non-filtered/filtered</caption>
+
+ <tr>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td><p>v2 B-tree Key</p></td>
- <td><p>This field is the B-tree key for retrieving the information
- from the version 2 B-tree for huge objects needed to access the
- object. See the description of <a href="#V2Btrees">v2 B-tree</a>
- records sub-type 1 & 2 for a description of the fields. New key
- values are derived from <em>Next Huge Object ID</em> in the
- <em>Fractal Heap Header</em>.</p>
+ <td>Version & Type</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />v2 B-tree Key<sup>L</sup><em>
+ (variable size)</em><br />
+ <br /></td>
+ </tr>
+
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;L&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Lengths&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version & Type</p></td>
+ <td>
+ <p>This is a bit field with the following definition:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>6-7</code></td>
+ <td>The current version of ID format. This document describes
+ version 0.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>4-5</code></td>
+ <td>The ID type. Huge objects have a value of <code>1</code>.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>0-3</code></td>
+ <td>Reserved.</td>
+ </tr>
+ </table>
+ <p></p>
+
</td>
</tr>
- </table>
- </div>
+ <tr>
+ <td><p>v2 B-tree Key</p></td>
+ <td><p>
+ This field is the B-tree key for retrieving the information from
+ the version 2 B-tree for huge objects needed to access the object.
+ See the description of <a href="#V2Btrees">v2 B-tree</a> records
+ sub-type 1 & 2 for a description of the fields. New key values are
+ derived from <em>Next Huge Object ID</em> in the <em>Fractal
+ Heap Header</em>.
+ </p></td>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>Fractal Heap ID for Huge Objects (sub-type 3): directly accessed, non-filtered
- </caption>
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap ID for Huge Objects (sub-type 3):
+ directly accessed, non-filtered</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td>Version & Type</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td>Version & Type</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4"><br />Address <sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Address <sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Length <sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Length <sup>L</sup><br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Version & Type</p></td>
- <td>
- <p>This is a bit field with the following definition:
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
+ <td><p>Version & Type</p></td>
+ <td>
+ <p>This is a bit field with the following definition:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
- <tr>
- <td align="center"><code>6-7</code></td>
- <td>The current version of ID format. This document
- describes version 0.
- </td>
- </tr>
- <tr>
- <td align="center"><code>4-5</code></td>
- <td>The ID type. Huge objects have a value of <code>1</code>.
- </td>
- </tr>
- <tr>
- <td align="center"><code>0-3</code></td>
- <td>Reserved.
- </td>
- </tr>
- </table></p>
+ <tr>
+ <td align="center"><code>6-7</code></td>
+ <td>The current version of ID format. This document describes
+ version 0.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>4-5</code></td>
+ <td>The ID type. Huge objects have a value of <code>1</code>.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>0-3</code></td>
+ <td>Reserved.</td>
+ </tr>
+ </table>
+ <p></p>
- </td>
+ </td>
</tr>
<tr>
@@ -5362,2899 +5492,2913 @@ III.F. Disk Format: Level 1F - Fractal Heap</a></h3>
<tr>
<td><p>Length</p></td>
- <td><p>This field is the length of the object in the file.</p>
- </td>
+ <td><p>This field is the length of the object in the file.</p></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>Fractal Heap ID for Huge Objects (sub-type 4): directly accessed, filtered
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap ID for Huge Objects (sub-type 4):
+ directly accessed, filtered</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td>Version & Type</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td>Version & Type</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4"><br />Address <sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Address <sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Length <sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Length <sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4">Filter Mask</td>
+ <td colspan="4">Filter Mask</td>
</tr>
<tr>
- <td colspan="4"><br />De-filtered Size <sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />De-filtered Size <sup>L</sup><br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
</tr>
<tr>
- <td>&nbsp;</td>
- <td>(Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Version & Type</p></td>
- <td>
- <p>This is a bit field with the following definition:
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
+ <td><p>Version & Type</p></td>
+ <td>
+ <p>This is a bit field with the following definition:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
- <tr>
- <td align="center"><code>6-7</code></td>
- <td>The current version of ID format. This document
- describes version 0.
- </td>
- </tr>
- <tr>
- <td align="center"><code>4-5</code></td>
- <td>The ID type. Huge objects have a value of <code>1</code>.
- </td>
- </tr>
- <tr>
- <td align="center"><code>0-3</code></td>
- <td>Reserved.
- </td>
- </tr>
- </table></p>
+ <tr>
+ <td align="center"><code>6-7</code></td>
+ <td>The current version of ID format. This document describes
+ version 0.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>4-5</code></td>
+ <td>The ID type. Huge objects have a value of <code>1</code>.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>0-3</code></td>
+ <td>Reserved.</td>
+ </tr>
+ </table>
+ <p></p>
- </td>
+ </td>
</tr>
<tr>
<td><p>Address</p></td>
- <td><p>This field is the address of the filtered object in the file.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Length</p></td>
- <td><p>This field is the length of the filtered object in the file.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Filter Mask</p></td>
- <td><p>This field is the I/O pipeline filter mask for the
- filtered object in the file.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Filtered Size</p></td>
- <td><p>This field is the size of the de-filtered object in the file.</p>
- </td>
- </tr>
+ <td><p>This field is the address of the filtered object in
+ the file.</p></td>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td><p>Length</p></td>
+ <td><p>This field is the length of the filtered object in
+ the file.</p></td>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>Fractal Heap ID for Managed Objects
- </caption>
+ <tr>
+ <td><p>Filter Mask</p></td>
+ <td><p>This field is the I/O pipeline filter mask for the
+ filtered object in the file.</p></td>
+ </tr>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
+ <td><p>Filtered Size</p></td>
+ <td><p>This field is the size of the de-filtered object in
+ the file.</p></td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap ID for Managed Objects</caption>
<tr>
- <td>Version & Type</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
+
<tr>
- <td colspan="4">Offset <em>(variable size)</em></td>
+ <td>Version & Type</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+ <tr>
+ <td colspan="4">Offset <em>(variable size)</em></td>
</tr>
<tr>
- <td colspan="4">Length <em>(variable size)</em></td>
+ <td colspan="4">Length <em>(variable size)</em></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version & Type</p></td>
- <td><p>This is a bit field with the following definition:
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>6-7</code></td>
- <td>The current version of ID format. This document
- describes version 0.
- </td>
- </tr>
- <tr>
- <td align="center"><code>4-5</code></td>
- <td>The ID type. Managed objects have a value of <code>0</code>.
- </td>
- </tr>
- <tr>
- <td align="center"><code>0-3</code></td>
- <td>Reserved.
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Offset</p></td>
- <td><p>This field is the offset of the object in the heap.
- This field&rsquo;s size is the minimum number of bytes
- necessary to encode the <em>Maximum Heap Size</em> value
- (from the <em>Fractal Heap Header</em>). For example, if the
- value of the <em>Maximum Heap Size</em> is less than 256 bytes,
- this field is 1 byte in length, a <em>Maximum Heap Size</em>
- of 256-65535 bytes uses a 2 byte length, and so on.</p></td>
- </tr>
-
- <tr>
- <td><p>Length</p></td>
- <td><p>This field is the length of the object in the heap. It
- is determined by taking the minimum value of <em>Maximum
- Direct Block Size</em> and <em>Maximum Size of Managed
- Objects</em> in the <em>Fractal Heap Header</em>. Again,
- the minimum number of bytes needed to encode that value is
- used for the size of this field.</p></td>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
- </table>
- </div>
-
-<br />
-<h3><a name="FreeSpaceManager">
-III.G. Disk Format: Level 1G - Free-space Manager</a></h3>
-
- <p>
- Free-space managers are used to describe space within a heap or
- the entire HDF5 file that is not currently used for that heap or
- file.
- </p>
-
- <p>
- The <em>free-space manager header</em> contains metadata information
- about the space being tracked, along with the address of the list
- of <em>free space sections</em> which actually describes the free
- space. The header records information about free-space sections being
- tracked, creation parameters for handling free-space sections of a
- client, and section information used to locate the collection of
- free-space sections.
- </p>
-
- <p>
- The <em>free-space section list</em> stores a collection of
- free-space sections that is specific to each <em>client</em> of the
- free-space manager.
-
- For example, the fractal heap is a client of the free space manager
- and uses it to track unused space within the heap. There are 4
- types of section records for the fractal heap, each of which has
- its own format, listed below.
- </p>
-
- <div align="center">
- <table class="format">
- <caption>
- Free-space Manager Header
- </caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <td><p>Version & Type</p></td>
+ <td><p>This is a bit field with the following definition:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>6-7</code></td>
+ <td>The current version of ID format. This document describes
+ version 0.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>4-5</code></td>
+ <td>The ID type. Managed objects have a value of <code>0</code>.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>0-3</code></td>
+ <td>Reserved.</td>
+ </tr>
+ </table>
+ <p></p></td>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td><p>Offset</p></td>
+ <td><p>
+ This field is the offset of the object in the heap. This
+ field&rsquo;s size is the minimum number of bytes necessary to
+ encode the <em>Maximum Heap Size</em> value (from the <em>Fractal
+ Heap Header</em>). For example, if the value of the <em>Maximum
+ Heap Size</em> is less than 256 bytes, this field is 1 byte in length,
+ a <em>Maximum Heap Size</em> of 256-65535 bytes uses a 2 byte
+ length, and so on.
+ </p></td>
</tr>
<tr>
- <td>Version</td>
- <td>Client ID</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td><p>Length</p></td>
+ <td><p>
+ This field is the length of the object in the heap. It is
+ determined by taking the minimum value of <em>Maximum Direct
+ Block Size</em> and <em>Maximum Size of Managed Objects</em> in the <em>Fractal
+ Heap Header</em>. Again, the minimum number of bytes needed to encode
+ that value is used for the size of this field.
+ </p></td>
</tr>
+ </table>
+</div>
+
+<br />
+<h3>
+ <a name="FreeSpaceManager"> III.G. Disk Format: Level 1G -
+ Free-space Manager</a>
+</h3>
+
+<p>Free-space managers are used to describe space within a heap or
+ the entire HDF5 file that is not currently used for that heap or file.
+</p>
+
+<p>
+ The <em>free-space manager header</em> contains metadata information
+ about the space being tracked, along with the address of the list of <em>free
+ space sections</em> which actually describes the free space. The header
+ records information about free-space sections being tracked, creation
+ parameters for handling free-space sections of a client, and section
+ information used to locate the collection of free-space sections.
+</p>
+
+<p>
+ The <em>free-space section list</em> stores a collection of free-space
+ sections that is specific to each <em>client</em> of the free-space
+ manager. For example, the fractal heap is a client of the free space
+ manager and uses it to track unused space within the heap. There are 4
+ types of section records for the fractal heap, each of which has its
+ own format, listed below.
+</p>
+
+<div align="center">
+ <table class="format">
+ <caption>Free-space Manager Header</caption>
<tr>
- <td colspan="4"><br />Total Space Tracked<sup>L</sup><br /><br /></td>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4"><br />Total Number of Sections<sup>L</sup><br /><br /></td>
+ <td colspan="4">Signature</td>
</tr>
<tr>
- <td colspan="4"><br />Number of Serialized Sections<sup>L</sup><br /><br /></td>
- </tr>
+ <td>Version</td>
+ <td>Client ID</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- <tr>
- <td colspan="4"><br />Number of Un-Serialized Sections<sup>L</sup><br /><br /></td>
- </tr>
+ <tr>
+ <td colspan="4"><br />Total Space Tracked<sup>L</sup><br />
+ <br /></td>
+ </tr>
- <tr>
- <td colspan="2">Number of Section Classes</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <tr>
+ <td colspan="4"><br />Total Number of Sections<sup>L</sup><br />
+ <br /></td>
+ </tr>
<tr>
- <td colspan="2">Shrink Percent</td>
- <td colspan="2">Expand Percent</td>
+ <td colspan="4"><br />Number of Serialized Sections<sup>L</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="2">Size of Address Space</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <td colspan="4"><br />Number of Un-Serialized Sections<sup>L</sup><br />
+ <br /></td>
+ </tr>
<tr>
- <td colspan="4"><br />Maximum Section Size <sup>L</sup><br /><br /></td>
- </tr>
+ <td colspan="2">Number of Section Classes</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
<tr>
- <td colspan="4"><br />Address of Serialized Section List<sup>O</sup><br /><br /></td>
+ <td colspan="2">Shrink Percent</td>
+ <td colspan="2">Expand Percent</td>
</tr>
<tr>
- <td colspan="4"><br />Size of Serialized Section List Used<sup>L</sup><br /><br /></td>
+ <td colspan="2">Size of Address Space</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4"><br />Allocated Size of Serialized Section List<sup>L</sup><br /><br /></td>
- </tr>
+ <td colspan="4"><br />Maximum Section Size <sup>L</sup><br />
+ <br /></td>
+ </tr>
- <tr>
- <td colspan="4">Checksum</td>
- </tr>
- </table>
+ <tr>
+ <td colspan="4"><br />Address of Serialized Section List<sup>O</sup><br />
+ <br /></td>
+ </tr>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <td colspan="4"><br />Size of Serialized Section List Used<sup>L</sup><br />
+ <br /></td>
+ </tr>
+
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td colspan="4"><br />Allocated Size of Serialized Section List<sup>L</sup><br />
+ <br /></td>
+ </tr>
- </div>
+ <tr>
+ <td colspan="4">Checksum</td>
+ </tr>
+ </table>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="35%">Field Name</th>
- <th>Description</th>
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ <tr>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
</tr>
+ </table>
+
+</div>
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>FSHD</code>&rdquo; is used to
- indicate the beginning of the Free-space Manager Header.
- This gives file consistency checking utilities a better chance of
- reconstructing a damaged file.
- </p>
- </td>
+ <th width="35%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Version</p></td>
- <td>
- <p>This is the version number for the Free-space Manager Header
- and this document describes version 0.</p>
- </td>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>FSHD</code>
+ &rdquo; is used to indicate the beginning of the Free-space Manager
+ Header. This gives file consistency checking utilities a better
+ chance of reconstructing a damaged file.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Client ID</p></td>
- <td>
- <p>This is the client ID for identifying the user of this
- free-space manager:
+ <td><p>Version</p></td>
+ <td>
+ <p>This is the version number for the Free-space Manager Header
+ and this document describes version 0.</p>
+ </td>
+ </tr>
+ <tr>
+ <td><p>Client ID</p></td>
+ <td>
+ <p>This is the client ID for identifying the user of this
+ free-space manager:</p>
<table class="list">
<tr>
- <th width="20%" align="center">ID</th>
- <th width="80%" align="left">Description</th>
+ <th width="20%" align="center">ID</th>
+ <th width="80%" align="left">Description</th>
</tr>
<tr>
- <td align="center"><code>0</code></td>
- <td>Fractal heap
- </td>
+ <td align="center"><code>0</code></td>
+ <td>Fractal heap</td>
</tr>
<tr>
- <td align="center"><code>1</code></td>
- <td>File
- </td>
+ <td align="center"><code>1</code></td>
+ <td>File</td>
</tr>
<tr>
- <td align="center"><code>2+</code></td>
- <td>Reserved.
- </td>
+ <td align="center"><code>2+</code></td>
+ <td>Reserved.</td>
</tr>
- </table></p>
+ </table>
+ <p></p>
- </td>
+ </td>
</tr>
- <tr>
- <td><p>Total Space Tracked</p></td>
- <td>
- <p>This is the total amount of free space being tracked, in bytes.
- </p>
- </td>
- </tr>
+ <tr>
+ <td><p>Total Space Tracked</p></td>
+ <td>
+ <p>This is the total amount of free space being tracked, in
+ bytes.</p>
+ </td>
+ </tr>
<tr>
- <td><p>Total Number of Sections</p></td>
- <td>
- <p>This is the total number of free-space sections being tracked.
- </p>
- </td>
+ <td><p>Total Number of Sections</p></td>
+ <td>
+ <p>This is the total number of free-space sections being
+ tracked.</p>
+ </td>
</tr>
- <tr>
- <td><p>Number of Serialized Sections</p></td>
- <td>
- <p>This is the number of serialized free-space sections being
- tracked.
- </p>
- </td>
- </tr>
- <tr>
- <td><p>Number of Un-Serialized Sections</p></td>
- <td>
- <p>This is the number of un-serialized free-space sections being
- managed. Un-serialized sections are created by the free-space
- client when the list of sections is read in.
- </p>
- </td>
+ <tr>
+ <td><p>Number of Serialized Sections</p></td>
+ <td>
+ <p>This is the number of serialized free-space sections being
+ tracked.</p>
+ </td>
+ </tr>
+ <tr>
+ <td><p>Number of Un-Serialized Sections</p></td>
+ <td>
+ <p>This is the number of un-serialized free-space sections being
+ managed. Un-serialized sections are created by the free-space
+ client when the list of sections is read in.</p>
+ </td>
</tr>
<tr>
- <td><p>Number of Section Classes</p></td>
- <td>
- <p>This is the number of section classes handled by this free space
- manager for the free-space client.
- </p>
- </td>
+ <td><p>Number of Section Classes</p></td>
+ <td>
+ <p>This is the number of section classes handled by this free
+ space manager for the free-space client.</p>
+ </td>
</tr>
<tr>
- <td><p>Shrink Percent</p></td>
- <td>
- <p>This is the percent of current size to shrink the allocated
- serialized free-space section list.
- </p>
- </td>
+ <td><p>Shrink Percent</p></td>
+ <td>
+ <p>This is the percent of current size to shrink the allocated
+ serialized free-space section list.</p>
+ </td>
</tr>
<tr>
- <td><p>Expand Percent</p></td>
- <td>
- <p>This is the percent of current size to expand the allocated
- serialized free-space section list.
- </p>
- </td>
+ <td><p>Expand Percent</p></td>
+ <td>
+ <p>This is the percent of current size to expand the allocated
+ serialized free-space section list.</p>
+ </td>
</tr>
<tr>
- <td><p>Size of Address Space</p></td>
- <td>
- <p>This is the size of the address space that free-space sections
- are within. This is stored as the log<sub>2</sub> of the
- actual value (in other words, the number of bits required
- to store values within that address space).
- </p>
- </td>
+ <td><p>Size of Address Space</p></td>
+ <td>
+ <p>
+ This is the size of the address space that free-space sections are
+ within. This is stored as the log<sub>2</sub> of the actual value
+ (in other words, the number of bits required to store values within
+ that address space).
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Maximum Section Size</p></td>
- <td>
- <p>This is the maximum size of a section to be tracked.
- </p>
- </td>
+ <td><p>Maximum Section Size</p></td>
+ <td>
+ <p>This is the maximum size of a section to be tracked.</p>
+ </td>
</tr>
<tr>
- <td><p>Address of Serialized Section List</p></td>
- <td>
- <p>This is the address where the serialized free-space section
- list is stored.
- </p>
- </td>
+ <td><p>Address of Serialized Section List</p></td>
+ <td>
+ <p>This is the address where the serialized free-space section
+ list is stored.</p>
+ </td>
</tr>
<tr>
- <td><p>Size of Serialized Section List Used</p></td>
- <td>
- <p>This is the size of the serialized free-space section
- list used (in bytes). This value must be less than
- or equal to the <em>allocated size of serialized section
- list</em>, below.
- </p>
- </td>
+ <td><p>Size of Serialized Section List Used</p></td>
+ <td>
+ <p>
+ This is the size of the serialized free-space section list used (in
+ bytes). This value must be less than or equal to the <em>allocated
+ size of serialized section list</em>, below.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Allocated Size of Serialized Section List</p></td>
- <td>
- <p>This is the size of serialized free-space section list
- actually allocated (in bytes).
- </p>
- </td>
+ <td><p>Allocated Size of Serialized Section List</p></td>
+ <td>
+ <p>This is the size of serialized free-space section list
+ actually allocated (in bytes).</p>
+ </td>
</tr>
<tr>
- <td><p>Checksum</p></td>
- <td>
- <p>This is the checksum for the free-space manager header.</p>
- </td>
+ <td><p>Checksum</p></td>
+ <td>
+ <p>This is the checksum for the free-space manager header.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <p>The free-space sections being managed are stored in a
- <em>free-space section list</em>, described below. The sections
- in the free-space section list are stored in the following way:
- a count of the number of sections describing a particular size of
- free space and the size of the free-space described (in bytes),
- followed by a list of section description records; then another
- section count and size, followed by the list of section
- descriptions for that size; and so on.</p>
-
-
- <div align="center">
- <table class="format">
- <caption>
- Free-space Section List
- </caption>
+<br />
+<p>
+ The free-space sections being managed are stored in a <em>free-space
+ section list</em>, described below. The sections in the free-space section
+ list are stored in the following way: a count of the number of sections
+ describing a particular size of free space and the size of the
+ free-space described (in bytes), followed by a list of section
+ description records; then another section count and size, followed by
+ the list of section descriptions for that size; and so on.
+</p>
+
+
+<div align="center">
+ <table class="format">
+ <caption>Free-space Section List</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td colspan="4">Signature</td>
</tr>
<tr>
- <td>Version</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td>Version</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4"><br />Free-space Manager Header Address<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Free-space Manager Header Address<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4">Number of Section Records in Set #0 <em>(variable size)</em></td>
+ <td colspan="4">Number of Section Records in Set #0 <em>(variable
+ size)</em></td>
</tr>
<tr>
- <td colspan="4">Size of Free-space Section Described in Record Set #0 <em>(variable size)</em></td>
- </tr>
+ <td colspan="4">Size of Free-space Section Described in Record
+ Set #0 <em>(variable size)</em>
+ </td>
+ </tr>
- <tr>
- <td colspan="4">Record Set #0 Section Record #0 Offset<em>(variable size)</em></td>
- </tr>
+ <tr>
+ <td colspan="4">Record Set #0 Section Record #0 Offset<em>(variable
+ size)</em></td>
+ </tr>
- <tr>
- <td colspan="1">Record Set #0 Section Record #0 Type</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <tr>
+ <td colspan="1">Record Set #0 Section Record #0 Type</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- <tr>
- <td colspan="4">Record Set #0 Section Record #0 Data <em>(variable size)</em></td>
- </tr>
+ <tr>
+ <td colspan="4">Record Set #0 Section Record #0 Data <em>(variable
+ size)</em></td>
+ </tr>
- <tr>
- <td colspan="4">...</td>
- </tr>
+ <tr>
+ <td colspan="4">...</td>
+ </tr>
- <tr>
- <td colspan="4">Record Set #0 Section Record #K-1 Offset<em>(variable size)</em></td>
- </tr>
+ <tr>
+ <td colspan="4">Record Set #0 Section Record #K-1 Offset<em>(variable
+ size)</em></td>
+ </tr>
- <tr>
- <td colspan="1">Record Set #0 Section Record #K-1 Type</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <tr>
+ <td colspan="1">Record Set #0 Section Record #K-1 Type</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- <tr>
- <td colspan="4">Record Set #0 Section Record #K-1 Data <em>(variable size)</em></td>
- </tr>
+ <tr>
+ <td colspan="4">Record Set #0 Section Record #K-1 Data <em>(variable
+ size)</em></td>
+ </tr>
<tr>
- <td colspan="4">Number of Section Records in Set #1 <em>(variable size)</em></td>
+ <td colspan="4">Number of Section Records in Set #1 <em>(variable
+ size)</em></td>
</tr>
<tr>
- <td colspan="4">Size of Free-space Section Described in Record Set #1 <em>(variable size)</em></td>
- </tr>
+ <td colspan="4">Size of Free-space Section Described in Record
+ Set #1 <em>(variable size)</em>
+ </td>
+ </tr>
- <tr>
- <td colspan="4">Record Set #1 Section Record #0 Offset<em>(variable size)</em></td>
- </tr>
+ <tr>
+ <td colspan="4">Record Set #1 Section Record #0 Offset<em>(variable
+ size)</em></td>
+ </tr>
- <tr>
- <td colspan="1">Record Set #1 Section Record #0 Type</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <tr>
+ <td colspan="1">Record Set #1 Section Record #0 Type</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- <tr>
- <td colspan="4">Record Set #1 Section Record #0 Data <em>(variable size)</em></td>
- </tr>
+ <tr>
+ <td colspan="4">Record Set #1 Section Record #0 Data <em>(variable
+ size)</em></td>
+ </tr>
- <tr>
- <td colspan="4">...</td>
- </tr>
+ <tr>
+ <td colspan="4">...</td>
+ </tr>
- <tr>
- <td colspan="4">Record Set #1 Section Record #K-1 Offset<em>(variable size)</em></td>
- </tr>
+ <tr>
+ <td colspan="4">Record Set #1 Section Record #K-1 Offset<em>(variable
+ size)</em></td>
+ </tr>
- <tr>
- <td colspan="1">Record Set #1 Section Record #K-1 Type</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <tr>
+ <td colspan="1">Record Set #1 Section Record #K-1 Type</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- <tr>
- <td colspan="4">Record Set #1 Section Record #K-1 Data <em>(variable size)</em></td>
- </tr>
+ <tr>
+ <td colspan="4">Record Set #1 Section Record #K-1 Data <em>(variable
+ size)</em></td>
+ </tr>
- <tr>
- <td colspan="4"><strong>...</strong></td>
- </tr>
+ <tr>
+ <td colspan="4"><strong>...</strong></td>
+ </tr>
- <tr>
- <td colspan="4"><strong>...</strong></td>
- </tr>
+ <tr>
+ <td colspan="4"><strong>...</strong></td>
+ </tr>
<tr>
- <td colspan="4">Number of Section Records in Set #N-1 <em>(variable size)</em></td>
+ <td colspan="4">Number of Section Records in Set #N-1 <em>(variable
+ size)</em></td>
</tr>
<tr>
- <td colspan="4">Size of Free-space Section Described in Record Set #N-1 <em>(variable size)</em></td>
- </tr>
+ <td colspan="4">Size of Free-space Section Described in Record
+ Set #N-1 <em>(variable size)</em>
+ </td>
+ </tr>
- <tr>
- <td colspan="4">Record Set #N-1 Section Record #0 Offset<em>(variable size)</em></td>
- </tr>
+ <tr>
+ <td colspan="4">Record Set #N-1 Section Record #0 Offset<em>(variable
+ size)</em></td>
+ </tr>
- <tr>
- <td colspan="1">Record Set #N-1 Section Record #0 Type</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <tr>
+ <td colspan="1">Record Set #N-1 Section Record #0 Type</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- <tr>
- <td colspan="4">Record Set #N-1 Section Record #0 Data <em>(variable size)</em></td>
- </tr>
+ <tr>
+ <td colspan="4">Record Set #N-1 Section Record #0 Data <em>(variable
+ size)</em></td>
+ </tr>
- <tr>
- <td colspan="4">...</td>
- </tr>
+ <tr>
+ <td colspan="4">...</td>
+ </tr>
- <tr>
- <td colspan="4">Record Set #N-1 Section Record #K-1 Offset<em>(variable size)</em></td>
- </tr>
+ <tr>
+ <td colspan="4">Record Set #N-1 Section Record #K-1 Offset<em>(variable
+ size)</em></td>
+ </tr>
- <tr>
- <td colspan="1">Record Set #N-1 Section Record #K-1 Type</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <tr>
+ <td colspan="1">Record Set #N-1 Section Record #K-1 Type</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- <tr>
- <td colspan="4">Record Set #N-1 Section Record #K-1 Data <em>(variable size)</td>
- </tr>
+ <tr>
+ <td colspan="4">Record Set #N-1 Section Record #K-1 Data <em>(variable
+ size)</em></td>
+ </tr>
- <tr>
- <td colspan="4">Checksum</td>
- </tr>
- </table>
+ <tr>
+ <td colspan="4">Checksum</td>
+ </tr>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
- </div>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="35%">Field Name</th>
- <th>Description</th>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="35%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>FSSE</code>&rdquo; is used to
- indicate the beginning of the Free-space Section Information.
- This gives file consistency checking utilities a better chance of
- reconstructing a damaged file.
- </p>
- </td>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>FSSE</code>
+ &rdquo; is used to indicate the beginning of the Free-space Section
+ Information. This gives file consistency checking utilities a
+ better chance of reconstructing a damaged file.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Version</p></td>
- <td>
- <p>This is the version number for the Free-space Section List
- and this document describes version 0.</p>
- </td>
+ <td><p>Version</p></td>
+ <td>
+ <p>This is the version number for the Free-space Section List
+ and this document describes version 0.</p>
+ </td>
</tr>
<tr>
- <td><p>Free-space Manager Header Address</p></td>
- <td>
- <p>This is the address of the <em>Free-space Manager Header</em>.
- This field is principally used for file
- integrity checking.
- </p>
- </td>
+ <td><p>Free-space Manager Header Address</p></td>
+ <td>
+ <p>
+ This is the address of the <em>Free-space Manager Header</em>. This
+ field is principally used for file integrity checking.
+ </p>
+ </td>
</tr>
- <tr>
- <td><p>Number of Section Records for Set #N</p></td>
- <td>
- <p>This is the number of free-space section records for set #N.
- The length of this field is the minimum number of bytes needed
- to store the <em>number of serialized sections</em> (from the
- <em>free-space manager header</em>).
- </p>
+ <tr>
+ <td><p>Number of Section Records for Set #N</p></td>
+ <td>
+ <p>
+ This is the number of free-space section records for set #N. The
+ length of this field is the minimum number of bytes needed to store
+ the <em>number of serialized sections</em> (from the <em>free-space
+ manager header</em>).
+ </p>
- <p>
- The number of sets of free-space section records is
- determined by the <em>size of serialized section list</em> in
- the <em>free-space manager header</em>.
- </p>
- </td>
- </tr>
+ <p>
+ The number of sets of free-space section records is determined by
+ the <em>size of serialized section list</em> in the <em>free-space
+ manager header</em>.
+ </p>
+ </td>
+ </tr>
<tr>
- <td><p>Section Size for Record Set #N</p></td>
- <td>
- <p>This is the size (in bytes) of the free-space section described
- for <em>all</em> the section records in set #N.
- </p>
+ <td><p>Section Size for Record Set #N</p></td>
+ <td>
+ <p>
+ This is the size (in bytes) of the free-space section described for
+ <em>all</em> the section records in set #N.
+ </p>
- <p>
- The length of this field is the minimum number of bytes needed
- to store the <em>maximum section size</em> (from the
- <em>free-space manager header</em>).
- </p>
- </td>
+ <p>
+ The length of this field is the minimum number of bytes needed to
+ store the <em>maximum section size</em> (from the <em>free-space
+ manager header</em>).
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Record Set #N Section #K Offset</p></td>
- <td>
- <p>This is the offset (in bytes) of the free-space section within
- the client for the free-space manager.
- </p>
+ <td><p>Record Set #N Section #K Offset</p></td>
+ <td>
+ <p>This is the offset (in bytes) of the free-space section
+ within the client for the free-space manager.</p>
- <p>
- The length of this field is the minimum number of bytes needed
- to store the <em>size of address space</em> (from the
- <em>free-space manager header</em>).
- </p>
- </td>
+ <p>
+ The length of this field is the minimum number of bytes needed to
+ store the <em>size of address space</em> (from the <em>free-space
+ manager header</em>).
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Record Set #N Section #K Type</p></td>
- <td>
- <p>This is the type of the section record, used to decode the
- <em>record set #N section #K data</em> information. The defined
- record type for <em>file</em> client is:
+ <td><p>Record Set #N Section #K Type</p></td>
+ <td>
+ <p>
+ This is the type of the section record, used to decode the <em>record
+ set #N section #K data</em> information. The defined record type for <em>file</em>
+ client is:
+ </p>
<table class="list">
<tr>
- <th width="20%" align="center">Type</th>
- <th width="80%" align="left">Description</th>
+ <th width="20%" align="center">Type</th>
+ <th width="80%" align="left">Description</th>
</tr>
<tr>
- <td align="center"><code>0</code></td>
- <td>File&rsquo;s section (a range of actual bytes in file)
- </td>
+ <td align="center"><code>0</code></td>
+ <td>File&rsquo;s section (a range of actual bytes in file)</td>
</tr>
<tr>
- <td align="center"><code>1+</code></td>
- <td>Reserved.
- </td>
+ <td align="center"><code>1+</code></td>
+ <td>Reserved.</td>
</tr>
- </table></p>
+ </table>
+ <p></p>
- <p>The defined record types for a <em>fractal heap</em> client are:
+ <p>
+ The defined record types for a <em>fractal heap</em> client are:
+ </p>
<table class="list">
<tr>
- <th width="20%" align="center">Type</th>
- <th width="80%" align="left">Description</th>
+ <th width="20%" align="center">Type</th>
+ <th width="80%" align="left">Description</th>
</tr>
<tr>
- <td align="center"><code>0</code></td>
- <td>Fractal heap &ldquo;single&rdquo; section
- </td>
+ <td align="center"><code>0</code></td>
+ <td>Fractal heap &ldquo;single&rdquo; section</td>
</tr>
<tr>
- <td align="center"><code>1</code></td>
- <td>Fractal heap &ldquo;first row&rdquo; section
- </td>
+ <td align="center"><code>1</code></td>
+ <td>Fractal heap &ldquo;first row&rdquo; section</td>
</tr>
<tr>
- <td align="center"><code>2</code></td>
- <td>Fractal heap &ldquo;normal row&rdquo; section
- </td>
+ <td align="center"><code>2</code></td>
+ <td>Fractal heap &ldquo;normal row&rdquo; section</td>
</tr>
<tr>
- <td align="center"><code>3</code></td>
- <td>Fractal heap &ldquo;indirect&rdquo; section
- </td>
+ <td align="center"><code>3</code></td>
+ <td>Fractal heap &ldquo;indirect&rdquo; section</td>
</tr>
<tr>
- <td align="center"><code>4+</code></td>
- <td>Reserved.
- </td>
+ <td align="center"><code>4+</code></td>
+ <td>Reserved.</td>
</tr>
- </table></p>
+ </table>
+ <p></p>
- </td>
+ </td>
</tr>
<tr>
- <td><p>Record Set #N Section #K Data</p></td>
- <td>
- <p>This is the section-type specific information for each record
- in the record set, described below.
- </p>
- </td>
+ <td><p>Record Set #N Section #K Data</p></td>
+ <td>
+ <p>This is the section-type specific information for each record
+ in the record set, described below.</p>
+ </td>
</tr>
<tr>
- <td><p>Checksum</p></td>
- <td>
- <p>This is the checksum for the <em>Free-space Section List</em>.
- </p>
- </td>
+ <td><p>Checksum</p></td>
+ <td>
+ <p>
+ This is the checksum for the <em>Free-space Section List</em>.
+ </p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <p>
- The section-type specific data for each free-space section record is
- described below:
- </p>
+<br />
+<p>The section-type specific data for each free-space section record
+ is described below:</p>
- <div align="center">
- <table class="format">
- <caption>
- File&rsquo;s Section Data Record
- </caption>
+<div align="center">
+ <table class="format">
+ <caption>File&rsquo;s Section Data Record</caption>
<tr>
- <td colspan="4"><em>No additional record data stored</em></td>
+ <td colspan="4"><em>No additional record data stored</em></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Fractal Heap &ldquo;Single&rdquo; Section Data Record
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap &ldquo;Single&rdquo; Section Data
+ Record</caption>
<tr>
- <td colspan="4"><em>No additional record data stored</em></td>
+ <td colspan="4"><em>No additional record data stored</em></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Fractal Heap &ldquo;First Row&rdquo; Section Data Record
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap &ldquo;First Row&rdquo; Section Data
+ Record</caption>
<tr>
- <td colspan="4"><em>Same format as &ldquo;indirect&rdquo; section data</em></td>
+ <td colspan="4"><em>Same format as &ldquo;indirect&rdquo;
+ section data</em></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Fractal Heap &ldquo;Normal Row&rdquo; Section Data Record
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap &ldquo;Normal Row&rdquo; Section Data
+ Record</caption>
<tr>
- <td colspan="4"><em>No additional record data stored</em></td>
+ <td colspan="4"><em>No additional record data stored</em></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Fractal Heap &ldquo;Indirect&rdquo; Section Data Record
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fractal Heap &ldquo;Indirect&rdquo; Section Data
+ Record</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4">Fractal Heap Indirect Block Offset <em>(variable size)</em></td>
+ <td colspan="4">Fractal Heap Indirect Block Offset <em>(variable
+ size)</em></td>
</tr>
<tr>
- <td colspan="2">Block Start Row</td>
- <td colspan="2">Block Start Column</td>
+ <td colspan="2">Block Start Row</td>
+ <td colspan="2">Block Start Column</td>
</tr>
<tr>
- <td colspan="2">Number of Blocks</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td colspan="2">Number of Blocks</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Fractal Heap Block Offset</p></td>
- <td>
- <p>The offset of the indirect block in the fractal heap&rsquo;s address
- space containing the empty blocks.
- </p>
- <p>
- The number of bytes used to encode this field is the minimum
- number of bytes needed to encode values for the <em>Maximum
- Heap Size</em> (in the fractal heap&rsquo;s header).
- </p>
- </td>
+ <td><p>Fractal Heap Block Offset</p></td>
+ <td>
+ <p>The offset of the indirect block in the fractal heap&rsquo;s
+ address space containing the empty blocks.</p>
+ <p>
+ The number of bytes used to encode this field is the minimum number
+ of bytes needed to encode values for the <em>Maximum Heap Size</em>
+ (in the fractal heap&rsquo;s header).
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Block Start Row</p></td>
- <td>
- <p>This is the row that the empty blocks start in.
- </p>
- </td>
+ <td><p>Block Start Row</p></td>
+ <td>
+ <p>This is the row that the empty blocks start in.</p>
+ </td>
</tr>
<tr>
- <td><p>Block Start Column</p></td>
- <td>
- <p>This is the column that the empty blocks start in.
- </p>
- </td>
+ <td><p>Block Start Column</p></td>
+ <td>
+ <p>This is the column that the empty blocks start in.</p>
+ </td>
</tr>
<tr>
- <td><p>Number of Blocks</p></td>
- <td>
- <p>This is the number of empty blocks covered by the section.
- </p>
- </td>
+ <td><p>Number of Blocks</p></td>
+ <td>
+ <p>This is the number of empty blocks covered by the section.</p>
+ </td>
</tr>
- </table>
- </div>
-
-<br />
-<h3><a name="SOHMTable">
-III.H. Disk Format: Level 1H - Shared Object Header Message Table</a></h3>
-
- <p>
- The <em>shared object header message table</em> is used to locate
- object
- header messages that are shared between two or more object headers
- in the file. Shared object header messages are stored and indexed
- in the file in one of two ways: indexed sequentially in a
- <em>shared header message list</em> or indexed with a v2 B-tree.
- The shared messages themselves are either stored in a fractal
- heap (when two or more objects share the message), or remain in an
- object&rsquo;s header (when only one object uses the message currently,
- but the message can be shared in the future).
- </p>
-
- <p>
- The <em>shared object header message table</em>
- contains a list of shared message index headers. Each index header
- records information about the version of the index format, the index
- storage type, flags for the message types indexed, the number of
- messages in the index, the address where the index resides,
- and the fractal heap address if shared messages are stored there.
- </p>
-
- <p>
- Each index can be either a list or a v2 B-tree and may transition
- between those two forms as the number of messages in the index
- varies. Each shared message record contains information used to
- locate the shared message from either a fractal heap or an object
- header. The types of messages that can be shared are: <em>Dataspace,
- Datatype, Fill Value, Filter Pipeline and Attribute</em>.
- </p>
-
- <p>
- The <em>shared object header message table</em> is pointed to
- from a <a href="#SOHMTableMessage">shared message table</a> message
- in the superblock extension for a file. This message stores the
- version of the table format, along with the number of index headers
- in the table.
- </p>
-
- <div align="center">
- <table class="format">
- <caption>
- Shared Object Header Message Table
- </caption>
+ </table>
+</div>
+
+<br />
+<h3>
+ <a name="SOHMTable"> III.H. Disk Format: Level 1H - Shared Object
+ Header Message Table</a>
+</h3>
+
+<p>
+ The <em>shared object header message table</em> is used to locate
+ object header messages that are shared between two or more object
+ headers in the file. Shared object header messages are stored and
+ indexed in the file in one of two ways: indexed sequentially in a <em>shared
+ header message list</em> or indexed with a v2 B-tree. The shared messages
+ themselves are either stored in a fractal heap (when two or more
+ objects share the message), or remain in an object&rsquo;s header (when
+ only one object uses the message currently, but the message can be
+ shared in the future).
+</p>
+
+<p>
+ The <em>shared object header message table</em> contains a list of
+ shared message index headers. Each index header records information
+ about the version of the index format, the index storage type, flags
+ for the message types indexed, the number of messages in the index, the
+ address where the index resides, and the fractal heap address if shared
+ messages are stored there.
+</p>
+
+<p>
+ Each index can be either a list or a v2 B-tree and may transition
+ between those two forms as the number of messages in the index varies.
+ Each shared message record contains information used to locate the
+ shared message from either a fractal heap or an object header. The
+ types of messages that can be shared are: <em>Dataspace, Datatype,
+ Fill Value, Filter Pipeline and Attribute</em>.
+</p>
+
+<p>
+ The <em>shared object header message table</em> is pointed to from a <a
+ href="#SOHMTableMessage">shared message table</a> message in the
+ superblock extension for a file. This message stores the version of the
+ table format, along with the number of index headers in the table.
+</p>
+
+<div align="center">
+ <table class="format">
+ <caption>Shared Object Header Message Table</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td colspan="4">Signature</td>
</tr>
<tr>
- <td>Version for index #0</td>
- <td>Index Type for index #0</td>
- <td colspan="2">Message Type Flags for index #0</td>
+ <td>Version for index #0</td>
+ <td>Index Type for index #0</td>
+ <td colspan="2">Message Type Flags for index #0</td>
</tr>
<tr>
- <td colspan="4">Minimum Message Size for index #0</td>
+ <td colspan="4">Minimum Message Size for index #0</td>
</tr>
<tr>
- <td colspan="2">List Cutoff for index #0</td>
- <td colspan="2">v2 B-tree Cutoff for index #0</td>
+ <td colspan="2">List Cutoff for index #0</td>
+ <td colspan="2">v2 B-tree Cutoff for index #0</td>
</tr>
<tr>
- <td colspan="2">Number of Messages for index #0</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <td colspan="2">Number of Messages for index #0</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- <tr>
- <td colspan="4"><br />Index Address<sup>O</sup> for index #0<br /><br /></td>
- </tr>
+ <tr>
+ <td colspan="4"><br />Index Address<sup>O</sup> for index #0<br />
+ <br /></td>
+ </tr>
- <tr>
- <td colspan="4"><br />Fractal Heap Address<sup>O</sup> for index #0<br /><br /></td>
- </tr>
+ <tr>
+ <td colspan="4"><br />Fractal Heap Address<sup>O</sup> for
+ index #0<br />
+ <br /></td>
+ </tr>
<tr>
- <td colspan="4">...</td>
- </tr>
+ <td colspan="4">...</td>
+ </tr>
<tr>
- <td colspan="4">...</td>
- </tr>
+ <td colspan="4">...</td>
+ </tr>
<tr>
- <td>Version for index #N-1</td>
- <td>Index Type for index #N-1</td>
- <td colspan="2">Message Type Flags for index #N-1</td>
+ <td>Version for index #N-1</td>
+ <td>Index Type for index #N-1</td>
+ <td colspan="2">Message Type Flags for index #N-1</td>
</tr>
<tr>
- <td colspan="4">Minimum Message Size for index #N-1</td>
+ <td colspan="4">Minimum Message Size for index #N-1</td>
</tr>
<tr>
- <td colspan="2">List Cutoff for index #N-1</td>
- <td colspan="2">v2 B-tree Cutoff for index #N-1</td>
+ <td colspan="2">List Cutoff for index #N-1</td>
+ <td colspan="2">v2 B-tree Cutoff for index #N-1</td>
</tr>
<tr>
- <td colspan="2">Number of Messages for index #N-1</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <td colspan="2">Number of Messages for index #N-1</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- <tr>
- <td colspan="4"><br />Index Address<sup>O</sup> for index #N-1<br /><br /></td>
- </tr>
+ <tr>
+ <td colspan="4"><br />Index Address<sup>O</sup> for index #N-1<br />
+ <br /></td>
+ </tr>
- <tr>
- <td colspan="4"><br />Fractal Heap Address<sup>O</sup> for index #N-1<br /><br /></td>
- </tr>
+ <tr>
+ <td colspan="4"><br />Fractal Heap Address<sup>O</sup> for
+ index #N-1<br />
+ <br /></td>
+ </tr>
- <tr>
- <td colspan="4">Checksum</td>
- </tr>
- </table>
+ <tr>
+ <td colspan="4">Checksum</td>
+ </tr>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="35%">Field Name</th>
- <th>Description</th>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="35%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>SMTB</code>&rdquo; is used to
- indicate the beginning of the Shared Object Header Message table.
- This gives file consistency checking utilities a better chance of
- reconstructing a damaged file.
- </p>
- </td>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>SMTB</code>
+ &rdquo; is used to indicate the beginning of the Shared Object
+ Header Message table. This gives file consistency checking
+ utilities a better chance of reconstructing a damaged file.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Version for index #N</p></td>
- <td>
- <p>This is the version number for the list of shared object header message
- indexes and this document describes version 0.</p>
- </td>
+ <td><p>Version for index #N</p></td>
+ <td>
+ <p>This is the version number for the list of shared object
+ header message indexes and this document describes version 0.</p>
+ </td>
</tr>
<tr>
- <td><p>Index Type for index #N</p></td>
- <td>
- <p>The type of index can be an unsorted list or a v2 B-tree.
- </p>
- </td>
+ <td><p>Index Type for index #N</p></td>
+ <td>
+ <p>The type of index can be an unsorted list or a v2 B-tree.</p>
+ </td>
</tr>
- <tr>
- <td><p>Message Type Flags for index #N</p></td>
- <td>
- <p>This field indicates the type of messages tracked in the index,
- as follows:
+ <tr>
+ <td><p>Message Type Flags for index #N</p></td>
+ <td>
+ <p>This field indicates the type of messages tracked in the
+ index, as follows:</p>
<table class="list">
<tr>
- <th width="20%" align="center">Bits</th>
- <th width="80%" align="left">Description</th>
+ <th width="20%" align="center">Bits</th>
+ <th width="80%" align="left">Description</th>
</tr>
<tr>
- <td align="center"><code>0</code></td>
- <td>If set, the index tracks <em>Dataspace Messages</em>.
- </td>
+ <td align="center"><code>0</code></td>
+ <td>If set, the index tracks <em>Dataspace Messages</em>.
+ </td>
</tr>
<tr>
- <td align="center"><code>1</code></td>
- <td>If set, the message tracks <em>Datatype Messages</em>.
- </td>
+ <td align="center"><code>1</code></td>
+ <td>If set, the message tracks <em>Datatype Messages</em>.
+ </td>
</tr>
<tr>
- <td align="center"><code>2</code></td>
- <td>If set, the message tracks <em>Fill Value Messages</em>.
- </td>
+ <td align="center"><code>2</code></td>
+ <td>If set, the message tracks <em>Fill Value Messages</em>.
+ </td>
</tr>
<tr>
- <td align="center"><code>3</code></td>
- <td>If set, the message tracks <em>Filter Pipeline Messages</em>.
- </td>
+ <td align="center"><code>3</code></td>
+ <td>If set, the message tracks <em>Filter Pipeline
+ Messages</em>.
+ </td>
</tr>
<tr>
- <td align="center"><code>4</code></td>
- <td>If set, the message tracks <em>Attribute Messages</em>.
- </td>
+ <td align="center"><code>4</code></td>
+ <td>If set, the message tracks <em>Attribute Messages</em>.
+ </td>
</tr>
<tr>
- <td align="center"><code>5-15</code></td>
- <td>Reserved (zero).
- </td>
+ <td align="center"><code>5-15</code></td>
+ <td>Reserved (zero).</td>
</tr>
- </table></p>
+ </table>
+ <p></p>
- <p>
- An index can track more than one type of message, but each type
- of message can only by in one index.
- </p>
- </td>
- </tr>
+ <p>An index can track more than one type of message, but each
+ type of message can only by in one index.</p>
+ </td>
+ </tr>
<tr>
- <td><p>Minimum Message Size for index #N</p></td>
- <td>
- <p>This is the message size sharing threshold for the index.
- If the encoded size of the message is less than this value, the
- message is not shared.
- </p>
- </td>
+ <td><p>Minimum Message Size for index #N</p></td>
+ <td>
+ <p>This is the message size sharing threshold for the index. If
+ the encoded size of the message is less than this value, the
+ message is not shared.</p>
+ </td>
</tr>
- <tr>
- <td><p>List Cutoff for index #N</p></td>
- <td>
- <p>This is the cutoff value for the indexing of messages to
- switch from a list to a v2 B-tree. If the number of messages
- is greater than this value, the index should be a v2 B-tree.
- </p>
- </td>
- </tr>
- <tr>
- <td><p>v2 B-tree Cutoff for index #N</p></td>
- <td>
- <p>This is the cutoff value for the indexing of messages to
- switch from a v2 B-tree back to a list. If the number of
- messages is less than this value, the index should be a list.
- </p>
- </td>
+ <tr>
+ <td><p>List Cutoff for index #N</p></td>
+ <td>
+ <p>This is the cutoff value for the indexing of messages to
+ switch from a list to a v2 B-tree. If the number of messages is
+ greater than this value, the index should be a v2 B-tree.</p>
+ </td>
+ </tr>
+ <tr>
+ <td><p>v2 B-tree Cutoff for index #N</p></td>
+ <td>
+ <p>This is the cutoff value for the indexing of messages to
+ switch from a v2 B-tree back to a list. If the number of messages
+ is less than this value, the index should be a list.</p>
+ </td>
</tr>
<tr>
- <td><p>Number of Messages for index #N</p></td>
- <td>
- <p>The number of shared messages being tracked for the index.
- </p>
- </td>
+ <td><p>Number of Messages for index #N</p></td>
+ <td>
+ <p>The number of shared messages being tracked for the index.</p>
+ </td>
</tr>
<tr>
- <td><p>Index Address for index #N</p></td>
- <td>
- <p>This field is the address of the list or v2 B-tree where the
- index nodes reside.
- </p>
- </td>
+ <td><p>Index Address for index #N</p></td>
+ <td>
+ <p>This field is the address of the list or v2 B-tree where the
+ index nodes reside.</p>
+ </td>
</tr>
<tr>
- <td><p>Fractal Heap Address for index #N</p></td>
- <td>
- <p>This field is the address of the fractal heap if shared messages
- are stored there.
- </p>
- </td>
+ <td><p>Fractal Heap Address for index #N</p></td>
+ <td>
+ <p>This field is the address of the fractal heap if shared
+ messages are stored there.</p>
+ </td>
</tr>
<tr>
- <td><p>Checksum</p></td>
- <td>
- <p>This is the checksum for the table.</p>
- </td>
+ <td><p>Checksum</p></td>
+ <td>
+ <p>This is the checksum for the table.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <p>
- Shared messages are indexed either with a <em>shared message record
- list</em>, described below, or using a v2 B-tree (using record type 7).
- The number of records in the <em>shared message record list</em> is
- determined in the index&rsquo;s entry in the <em>shared object header message
- table</em>.
- </p>
-
- <div align="center">
- <table class="format">
- <caption>
- Shared Message Record List
- </caption>
+<br />
+<p>
+ Shared messages are indexed either with a <em>shared message
+ record list</em>, described below, or using a v2 B-tree (using record type
+ 7). The number of records in the <em>shared message record list</em> is
+ determined in the index&rsquo;s entry in the <em>shared object
+ header message table</em>.
+</p>
+
+<div align="center">
+ <table class="format">
+ <caption>Shared Message Record List</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td colspan="4">Signature</td>
+ <td colspan="4">Signature</td>
</tr>
<tr>
- <td colspan="4">Shared Message Record #0</td>
+ <td colspan="4">Shared Message Record #0</td>
</tr>
<tr>
- <td colspan="4">Shared Message Record #1</td>
+ <td colspan="4">Shared Message Record #1</td>
</tr>
<tr>
- <td colspan="4">...</td>
+ <td colspan="4">...</td>
</tr>
<tr>
- <td colspan="4">Shared Message Record #N-1</td>
+ <td colspan="4">Shared Message Record #N-1</td>
</tr>
<tr>
- <td colspan="4">Checksum</td>
+ <td colspan="4">Checksum</td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>SMLI</code>&rdquo; is used to
- indicate the beginning of a list of index nodes.
- This gives file consistency checking utilities a better chance of
- reconstructing a damaged file.
- </p>
- </td>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>SMLI</code>
+ &rdquo; is used to indicate the beginning of a list of index nodes.
+ This gives file consistency checking utilities a better chance of
+ reconstructing a damaged file.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Shared Message Record #N</p></td>
- <td>
- <p>The record for locating the shared message, either in the
- fractal heap for the index, or an object header (see format for
- <em>index nodes</em> below).
- </p>
- </td>
+ <td><p>Shared Message Record #N</p></td>
+ <td>
+ <p>
+ The record for locating the shared message, either in the fractal
+ heap for the index, or an object header (see format for <em>index
+ nodes</em> below).
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Checksum</p></td>
- <td>
- <p>This is the checksum for the list.
- </p>
- </td>
+ <td><p>Checksum</p></td>
+ <td>
+ <p>This is the checksum for the list.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <p>
- The record for each shared message in an index is stored in one of the
- following forms:
- </p>
+<br />
+<p>The record for each shared message in an index is stored in one
+ of the following forms:</p>
- <div align="center">
- <table class="format">
- <caption>
- Shared Message Record, for messages stored in a fractal heap
- </caption>
+<div align="center">
+ <table class="format">
+ <caption>Shared Message Record, for messages stored in a
+ fractal heap</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td>Message Location</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td>Message Location</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4">Hash Value</td>
+ <td colspan="4">Hash Value</td>
</tr>
<tr>
- <td colspan="4">Reference Count</td>
+ <td colspan="4">Reference Count</td>
</tr>
<tr>
- <td colspan="4"><br />Fractal Heap ID<br /><br /></td>
+ <td colspan="4"><br />Fractal Heap ID<br />
+ <br /></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Message Location</p></td>
- <td>
- <p>This has a value of 0 indicating that the message is stored in
- the heap.
- </p>
- </td>
+ <td><p>Message Location</p></td>
+ <td>
+ <p>This has a value of 0 indicating that the message is stored
+ in the heap.</p>
+ </td>
</tr>
<tr>
- <td><p>Hash Value</p></td>
- <td>
- <p>This is the hash value for the message.
- </p>
- </td>
+ <td><p>Hash Value</p></td>
+ <td>
+ <p>This is the hash value for the message.</p>
+ </td>
</tr>
<tr>
- <td><p>Reference Count</p></td>
- <td>
- <p>This is the number of times the message is used in the file.
- </p>
- </td>
+ <td><p>Reference Count</p></td>
+ <td>
+ <p>This is the number of times the message is used in the file.
+ </p>
+ </td>
</tr>
<tr>
- <td><p>Fractal Heap ID</p></td>
- <td>
- <p>This is an 8-byte fractal heap ID for the message as stored in
- the fractal heap for the index.
- </p>
- </td>
+ <td><p>Fractal Heap ID</p></td>
+ <td>
+ <p>This is an 8-byte fractal heap ID for the message as stored
+ in the fractal heap for the index.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Shared Message Record, for messages stored in an object header
- </caption>
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Shared Message Record, for messages stored in an
+ object header</caption>
<tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
<tr>
- <td>Message Location</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
+ <td>Message Location</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
</tr>
<tr>
- <td colspan="4">Hash Value</td>
+ <td colspan="4">Hash Value</td>
</tr>
<tr>
- <td>Reserved</td>
- <td>Message Type</td>
- <td colspan="2">Creation Index</td>
+ <td>Reserved</td>
+ <td>Message Type</td>
+ <td colspan="2">Creation Index</td>
</tr>
<tr>
- <td colspan="4"><br />Object Header Address<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Object Header Address<sup>O</sup><br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Message Location</p></td>
- <td>
- <p>This has a value of 1 indicating that the message is stored in
- an object header.
- </p>
- </td>
+ <td><p>Message Location</p></td>
+ <td>
+ <p>This has a value of 1 indicating that the message is stored
+ in an object header.</p>
+ </td>
</tr>
<tr>
- <td><p>Hash Value</p></td>
- <td>
- <p>This is the hash value for the message.
- </p>
- </td>
+ <td><p>Hash Value</p></td>
+ <td>
+ <p>This is the hash value for the message.</p>
+ </td>
</tr>
<tr>
- <td><p>Message Type</p></td>
- <td>
- <p>This is the message type in the object header.
- </p>
- </td>
+ <td><p>Message Type</p></td>
+ <td>
+ <p>This is the message type in the object header.</p>
+ </td>
</tr>
<tr>
- <td><p>Creation Index</p></td>
- <td>
- <p>This is the creation index of the message within the object
- header.
- </p>
- </td>
+ <td><p>Creation Index</p></td>
+ <td>
+ <p>This is the creation index of the message within the object
+ header.</p>
+ </td>
</tr>
<tr>
- <td><p>Object Header Address</p></td>
- <td>
- <p>This is the address of the object header where the message is
- located.
- </p>
- </td>
+ <td><p>Object Header Address</p></td>
+ <td>
+ <p>This is the address of the object header where the message is
+ located.</p>
+ </td>
</tr>
- </table>
- </div>
+ </table>
+</div>
<br />
<br />
<hr />
-<h2><a name="DataObject">
-IV. Disk Format: Level 2 - Data Objects </a></h2>
-
- <p>Data objects contain the &ldquo;real&rdquo; user-visible information in the file.
- These objects compose the scientific data and other information which
- are generally thought of as &ldquo;data&rdquo; by the end-user. All the
- other information in the file is provided as a framework for
- storing and accessing these data objects.
- </p>
-
- <p>A data object is composed of header and data
- information. The header information contains the information
- needed to interpret the data information for the object as
- well as additional &ldquo;metadata&rdquo; or pointers to additional
- &ldquo;metadata&rdquo; used to describe or annotate each object.
- </p>
-
-<br />
-<h3><a name="ObjectHeader">
-IV.A. Disk Format: Level 2A - Data Object Headers</a></h3>
-
- <p>The header information of an object is designed to encompass
- all of the information about an object, except for the data itself.
- This information includes the dataspace, the datatype, information
- about how the data is stored on disk (in external files, compressed,
- broken up in blocks, and so on), as well as other information used
- by the library to speed up access to the data objects or maintain
- a file&rsquo;s integrity. Information stored by user applications
- as attributes is also stored in the object&rsquo;s header. The header
- of each object is not necessarily located immediately prior to the
- object&rsquo;s data in the file and in fact may be located in any
- position in the file. The order of the messages in an object header
- is not significant.</p>
-
- <p>Object headers are composed of a prefix and a set of messages. The
- prefix contains the information needed to interpret the messages and
- a small amount of metadata about the object, and the messages contain
- the majority of the metadata about the object.
- </p>
-
-<br />
-<h3><a name="ObjectHeaderPrefix">
-IV.A.1. Disk Format: Level 2A1 - Data Object Header Prefix</a></h3>
-
-<br />
-<h4><a name="V1ObjectHeaderPrefix">
-IV.A.1.a. Version 1 Data Object Header Prefix</a></h4>
-
- <p>Header messages are aligned on 8-byte boundaries for version 1
- object headers.
- </p>
-
- <div align="center">
- <table class="format">
- <caption>
- Version 1 Object Header
- </caption>
-
- <tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Reserved (zero)</td>
- <td colspan="2">Total Number of Header Messages</td>
- </tr>
-
- <tr>
- <td colspan="4">Object Reference Count</td>
- </tr>
-
- <tr>
- <td colspan="4">Object Header Size</td>
- </tr>
-
- <tr>
- <td colspan="2">Header Message Type #1</td>
- <td colspan="2">Size of Header Message Data #1</td>
- </tr>
-
- <tr>
- <td>Header Message #1 Flags</td>
- <td colspan="3">Reserved (zero)</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Header Message Data #1<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
-
- <tr>
- <td colspan="2">Header Message Type #n</td>
- <td colspan="2">Size of Header Message Data #n</td>
- </tr>
-
- <tr>
- <td>Header Message #n Flags</td>
- <td colspan="3">Reserved (zero)</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Header Message Data #n<br /><br /></td>
- </tr>
- </table>
- </div>
+<h2>
+ <a name="DataObject"> IV. Disk Format: Level 2 - Data Objects </a>
+</h2>
+
+<p>Data objects contain the &ldquo;real&rdquo; user-visible
+ information in the file. These objects compose the scientific data and
+ other information which are generally thought of as &ldquo;data&rdquo;
+ by the end-user. All the other information in the file is provided as a
+ framework for storing and accessing these data objects.</p>
+
+<p>A data object is composed of header and data information. The
+ header information contains the information needed to interpret the
+ data information for the object as well as additional
+ &ldquo;metadata&rdquo; or pointers to additional &ldquo;metadata&rdquo;
+ used to describe or annotate each object.</p>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td>
- <p>This value is used to determine the format of the
- information in the object header. When the format of the
- object header is changed, the version number
- is incremented and can be used to determine how the
- information in the object header is formatted. This
- is version one (1) (there was no version zero (0)) of the
- object header.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Total Number of Header Messages</p></td>
- <td>
- <p>This value determines the total number of messages listed in
- object headers for this object. This value includes the messages
- in continuation messages for this object.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Object Reference Count</p></td>
- <td>
- <p>This value specifies the number of &ldquo;hard links&rdquo; to this object
- within the current file. References to the object from external
- files, &ldquo;soft links&rdquo; in this file and object references in this
- file are not tracked.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Object Header Size</p></td>
- <td>
- <p>This value specifies the number of bytes of header message data
- following this length field that contain object header messages
- for this object header. This value does not include the size of
- object header continuation blocks for this object elsewhere in the
- file.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Header Message #n Type</p></td>
- <td>
- <p>This value specifies the type of information included in the
- following header message data. The message types for
- header messages are defined in sections below.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Size of Header Message #n Data</p></td>
- <td>
- <p>This value specifies the number of bytes of header
- message data following the header message type and length
- information for the current message. The size includes
- padding bytes to make the message a multiple of eight
- bytes.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Header Message #n Flags</p></td>
- <td>
- <p>This is a bit field with the following definition:
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>If set, the message data is constant. This is used
- for messages like the datatype message of a dataset.
- </td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td>If set, the message is <em>shared</em> and stored
- in another location than the object header. The Header
- Message Data field contains a Shared Message
- (described in the <a href="#ObjectHeaderMessages">Data Object Header Messages</a>
- section below)
- and the Size of Header Message Data field
- contains the size of that Shared Message.
- </td>
- </tr>
- <tr>
- <td align="center"><code>2</code></td>
- <td>If set, the message should not be shared.
- </td>
- </tr>
- <tr>
- <td align="center"><code>3</code></td>
- <td>If set, the HDF5 decoder should fail to open this object
- if it does not understand the message&rsquo;s type and the file
- is open with permissions allowing write access to the file.
- (Normally, unknown messages can just be ignored by HDF5
- decoders)
- </td>
- </tr>
- <tr>
- <td align="center"><code>4</code></td>
- <td>If set, the HDF5 decoder should set bit 5 of this
- message&rsquo;s flags (in other words, this bit field)
- if it does not understand the message&rsquo;s type
- and the object is modified in any way. (Normally,
- unknown messages can just be ignored by HDF5
- decoders)
- </td>
- </tr>
- <tr>
- <td align="center"><code>5</code></td>
- <td>If set, this object was modified by software that did not
- understand this message.
- (Normally, unknown messages should just be ignored by HDF5
- decoders) (Can be used to invalidate an index or a similar
- feature)
- </td>
- </tr>
- <tr>
- <td align="center"><code>6</code></td>
- <td>If set, this message is shareable.
- </td>
- </tr>
- <tr>
- <td align="center"><code>7</code></td>
- <td>If set, the HDF5 decoder should always fail to open this
- object if it does not understand the message&rsquo;s type (whether
- it is open for read-only or read-write access). (Normally,
- unknown messages can just be ignored by HDF5 decoders)
- </td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>Header Message #n Data</p></td>
- <td>
- <p>The format and length of this field is determined by the
- header message type and size respectively. Some header
- message types do not require any data and this information
- can be eliminated by setting the length of the message to
- zero. The data is padded with enough zeroes to make the
- size a multiple of eight.
- </p>
- </td>
- </tr>
- </table>
- </div>
-
-<br />
-<h4><a name="V2ObjectHeaderPrefix">
-IV.A.1.b. Version 2 Data Object Header Prefix</a></h4>
-
- <p>Note that the &ldquo;total number of messages&rdquo; field has been dropped from
- the data object header prefix in this version. The number of messages
- in the data object header is just determined by the messages encountered
- in all the object header blocks.</p>
-
- <p>Note also that the fields and messages in this version of data object
- headers have <em>no</em> alignment or padding bytes inserted - they are
- stored packed together.</p>
-
- <div align="center">
- <table class="format">
- <caption>
- Version 2 Object Header
- </caption>
-
- <tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
-
- <tr>
- <td colspan="4">Signature</td>
- </tr>
- <tr>
- <td>Version</td>
- <td>Flags</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4">Access time <em>(optional)</em></td>
- </tr>
-
- <tr>
- <td colspan="4">Modification Time <em>(optional)</em></td>
- </tr>
-
- <tr>
- <td colspan="4">Change Time <em>(optional)</em></td>
- </tr>
-
- <tr>
- <td colspan="4">Birth Time <em>(optional)</em></td>
- </tr>
-
- <tr>
- <td colspan="2">Maximum # of compact attributes <em>(optional)</em></td>
- <td colspan="2">Minimum # of dense attributes <em>(optional)</em></td>
- </tr>
-
- <tr>
- <td>Size of Chunk #0 <em>(variable size)</em></td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td>Header Message Type #1</td>
- <td colspan="2">Size of Header Message Data #1</td>
- <td>Header Message #1 Flags</td>
- </tr>
-
- <tr>
- <td colspan="2">Header Message #1 Creation Order <em>(optional)</em></td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Header Message Data #1<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
-
- <tr>
- <td>Header Message Type #n</td>
- <td colspan="2">Size of Header Message Data #n</td>
- <td>Header Message #n Flags</td>
- </tr>
-
- <tr>
- <td colspan="2">Header Message #n Creation Order <em>(optional)</em></td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Header Message Data #n<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4">Gap <em>(optional, variable size)</em></td>
- </tr>
-
- <tr>
- <td colspan="4">Checksum</td>
- </tr>
- </table>
- </div>
+<br />
+<h3>
+ <a name="ObjectHeader"> IV.A. Disk Format: Level 2A - Data Object
+ Headers</a>
+</h3>
+
+<p>The header information of an object is designed to encompass all
+ of the information about an object, except for the data itself. This
+ information includes the dataspace, the datatype, information about how
+ the data is stored on disk (in external files, compressed, broken up in
+ blocks, and so on), as well as other information used by the library to
+ speed up access to the data objects or maintain a file&rsquo;s
+ integrity. Information stored by user applications as attributes is
+ also stored in the object&rsquo;s header. The header of each object is
+ not necessarily located immediately prior to the object&rsquo;s data in
+ the file and in fact may be located in any position in the file. The
+ order of the messages in an object header is not significant.</p>
+
+<p>Object headers are composed of a prefix and a set of messages.
+ The prefix contains the information needed to interpret the messages
+ and a small amount of metadata about the object, and the messages
+ contain the majority of the metadata about the object.</p>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>OHDR</code>&rdquo;
- is used to indicate the
- beginning of an object header. This gives file consistency
- checking utilities a better chance of reconstructing a
- damaged file.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td>
- <p>This field has a value of 2 indicating version 2 of the object header.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Flags</p></td>
- <td>
- <p>This field is a bit field indicating additional information
- about the object header.
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit(s)</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0-1</code></td>
- <td>This two bit field determines the size of the
- <em>Size of Chunk #0</em> field. The values are:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
+<br />
+<h3>
+ <a name="ObjectHeaderPrefix"> IV.A.1. Disk Format: Level 2A1 - Data
+ Object Header Prefix</a>
+</h3>
- <tr>
- <td align="center"><code>0</code></td>
- <td>The <em>Size of Chunk #0</em> field is 1 byte.
- </td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td>The <em>Size of Chunk #0</em> field is 2 bytes.
- </td>
- </tr>
- <tr>
- <td align="center"><code>2</code></td>
- <td>The <em>Size of Chunk #0</em> field is 4 bytes.
- </td>
- </tr>
- <tr>
- <td align="center"><code>3</code></td>
- <td>The <em>Size of Chunk #0</em> field is 8 bytes.
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
- <tr>
- <td align="center"><code>2</code></td>
- <td>If set, attribute creation order is tracked.</td>
- </tr>
- <tr>
- <td align="center"><code>3</code></td>
- <td>If set, attribute creation order is indexed.</td>
- </tr>
- <tr>
- <td align="center"><code>4</code></td>
- <td>If set, non-default attribute storage phase change
- values are stored.</td>
- </tr>
- <tr>
- <td align="center"><code>5</code></td>
- <td>If set, access, modification, change and birth times
- are stored.</td>
- </tr>
- <tr>
- <td align="center"><code>6-7</code></td>
- <td>Reserved</td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>Access Time</p></td>
- <td>
- <p>This 32-bit value represents the number of seconds after the
- UNIX epoch when the object&rsquo;s raw data was last accessed
- (in other words, read or written).
- </p>
- <p>This field is present if bit 5 of <em>flags</em> is set.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Modification Time</p></td>
- <td>
- <p>This 32-bit value represents the number of seconds after
- the UNIX epoch when the object&rsquo;s raw data was last
- modified (in other words, written).
- </p>
- <p>This field is present if bit 5 of <em>flags</em> is set.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Change Time</p></td>
- <td>
- <p>This 32-bit value represents the number of seconds after the
- UNIX epoch when the object&rsquo;s metadata was last changed.
- </p>
- <p>This field is present if bit 5 of <em>flags</em> is set.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Birth Time</p></td>
- <td>
- <p>This 32-bit value represents the number of seconds after the
- UNIX epoch when the object was created.
- </p>
- <p>This field is present if bit 5 of <em>flags</em> is set.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Maximum # of compact attributes</p></td>
- <td>
- <p>This is the maximum number of attributes to store in the compact
- format before switching to the indexed format.
- </p>
- <p>This field is present if bit 4 of <em>flags</em> is set.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Minimum # of dense attributes</p></td>
- <td>
- <p>This is the minimum number of attributes to store in the indexed
- format before switching to the compact format.
- </p>
- <p>This field is present if bit 4 of <em>flags</em> is set.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Size of Chunk #0</p></td>
- <td>
- <p>
- This unsigned value specifies the number of bytes of header
- message data following this field that contain object header
- information.
- </p>
- <p>
- This value does not include the size of object header
- continuation blocks for this object elsewhere in the file.
- </p>
- <p>
- The length of this field varies depending on bits 0 and 1 of
- the <em>flags</em> field.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Header Message #n Type</p></td>
- <td>
- <p>Same format as version 1 of the object header, described above.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Size of Header Message #n Data</p></td>
- <td>
- <p>This value specifies the number of bytes of header
- message data following the header message type and length
- information for the current message. The size of messages
- in this version does <em>not</em> include any padding bytes.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Header Message #n Flags</p></td>
- <td>
- <p>Same format as version 1 of the object header, described above.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Header Message #n Creation Order</p></td>
- <td>
- <p>This field stores the order that a message of a given type
- was created in.
- </p>
- <p>This field is present if bit 2 of <em>flags</em> is set.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Header Message #n Data</p></td>
- <td>
- <p>Same format as version 1 of the object header, described above.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Gap</p></td>
- <td>
- <p>A gap in an object header chunk is inferred by the end of the
- messages for the chunk before the beginning of the chunk&rsquo;s
- checksum. Gaps are always smaller than the size of an
- object header message prefix (message type + message size +
- message flags).
- </p>
- <p>Gaps are formed when a message (typically an attribute message)
- in an earlier chunk is deleted and a message from a later
- chunk that does not quite fit into the free space is moved
- into the earlier chunk.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Checksum</p></td>
- <td>
- <p>This is the checksum for the object header chunk.
- </p>
- </td>
+<br />
+<h4>
+ <a name="V1ObjectHeaderPrefix"> IV.A.1.a. Version 1 Data Object
+ Header Prefix</a>
+</h4>
+
+<p>Header messages are aligned on 8-byte boundaries for version 1
+ object headers.</p>
+
+<div align="center">
+ <table class="format">
+ <caption>Version 1 Object Header</caption>
+
+ <tr>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
</tr>
- </table>
- </div>
-
- <p>The header message types and the message data associated with
- them compose the critical &ldquo;metadata&rdquo; about each object. Some
- header messages are required for each object while others are
- optional. Some optional header messages may also be repeated
- several times in the header itself, the requirements and number
- of times allowed in the header will be noted in each header
- message description below.
- </p>
-
-
-<br />
-<h3><a name="ObjectHeaderMessages">
-IV.A.2. Disk Format: Level 2A2 - Data Object Header Messages</a></h3>
-
- <p>Data object header messages are small pieces of metadata that are
- stored in the data object header for each object in an HDF5 file.
- Data object header messages provide the metadata required to describe
- an object and its contents, as well as optional pieces of metadata
- that annotate the meaning or purpose of the object.
- </p>
-
- <p>Data object header messages are either stored directly in the data
- object header for the object or are shared between multiple objects
- in the file. When a message is shared, a flag in the <em>Message Flags</em>
- indicates that the actual <em>Message Data</em>
- portion of that message is stored in another location (such as another
- data object header, or a heap in the file) and the <em>Message Data</em>
- field contains the information needed to locate the actual information
- for the message.
- </p>
-
- <p>
- The format of shared message data is described here:</p>
-
- <div align="center">
- <table class="format">
- <caption>
- Shared Message (Version 1)
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Type</td>
- <td colspan="2">Reserved (zero)</td>
- </tr>
-
- <tr>
- <td colspan="4">Reserved (zero)</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Address<sup>O</sup><br /><br /></td>
- </tr>
- </table>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td>Version</td>
+ <td>Reserved (zero)</td>
+ <td colspan="2">Total Number of Header Messages</td>
+ </tr>
- </div>
+ <tr>
+ <td colspan="4">Object Reference Count</td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number is used when there are changes in the format
- of a shared object message and is described here:
- <table class="list">
- <tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Never used.</td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>Used by the library before version 1.6.1.
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Type</p></td>
- <td><p>The type of shared message location:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Message stored in another object&rsquo;s header (a <em>committed</em>
- message).
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Address</p></td>
- <td><p>The address of the object header
- containing the message to be shared.</p>
- </td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4">Object Header Size</td>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Shared Message (Version 2)
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Type</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Address<sup>O</sup><br /><br /></td>
- </tr>
- </table>
+ <tr>
+ <td colspan="2">Header Message Type #1</td>
+ <td colspan="2">Size of Header Message Data #1</td>
+ </tr>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
- </div>
+ <td>Header Message #1 Flags</td>
+ <td colspan="3">Reserved (zero)</td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number is used when there are changes in the format
- of a shared object message and is described here:
- <table class="list">
- <tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>2</code></td>
- <td>Used by the library of version 1.6.1 and after.
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Type</p></td>
- <td><p>The type of shared message location:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Message stored in another object&rsquo;s header (a <em>committed</em>
- message).
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Address</p></td>
- <td><p>The address of the object header
- containing the message to be shared.</p></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4"><br />Header Message Data #1<br />
+ <br /></td>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Shared Message (Version 3)
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Type</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4">Location <em>(variable size)</em></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number indicates changes in the format of shared
- object message and is described here:
- <table class="list">
- <tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>3</code></td>
- <td>Used by the library of version 1.8 and after. In this
- version, the <em>Type</em> field can indicate that
- the message is stored in the fractal heap.
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Type</p></td>
- <td><p>The type of shared message location:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Message is not shared and is not shareable.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>Message stored in file&rsquo;s <em>shared object header message</em>
- heap (a <em>shared</em> message).
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>2</code></td>
- <td>Message stored in another object&rsquo;s header (a <em>committed</em>
- message).
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>3</code></td>
- <td>Message stored is not shared, but is shareable.
- </td>
- </tr>
-
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Location</p></td>
- <td><p>This field contains either a <em>Size of Offsets</em>-bytes
- address of the object header
- containing the message to be shared, or an 8-byte fractal heap ID
- for the message in the file&rsquo;s <em>shared object header message</em>
- heap.
- </p>
- </td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="2">Header Message Type #n</td>
+ <td colspan="2">Size of Header Message Data #n</td>
+ </tr>
+ <tr>
+ <td>Header Message #n Flags</td>
+ <td colspan="3">Reserved (zero)</td>
+ </tr>
- <p>The following is a list of currently defined header messages:
- </p>
+ <tr>
+ <td colspan="4"><br />Header Message Data #n<br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="NILMessage">IV.A.2.a. The NIL Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>This value is used to determine the format of the information
+ in the object header. When the format of the object header is
+ changed, the version number is incremented and can be used to
+ determine how the information in the object header is formatted.
+ This is version one (1) (there was no version zero (0)) of the
+ object header.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Total Number of Header Messages</p></td>
+ <td>
+ <p>This value determines the total number of messages listed in
+ object headers for this object. This value includes the messages in
+ continuation messages for this object.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Object Reference Count</p></td>
+ <td>
+ <p>This value specifies the number of &ldquo;hard links&rdquo;
+ to this object within the current file. References to the object
+ from external files, &ldquo;soft links&rdquo; in this file and
+ object references in this file are not tracked.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Object Header Size</p></td>
+ <td>
+ <p>This value specifies the number of bytes of header message
+ data following this length field that contain object header
+ messages for this object header. This value does not include the
+ size of object header continuation blocks for this object elsewhere
+ in the file.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Header Message #n Type</p></td>
+ <td>
+ <p>This value specifies the type of information included in the
+ following header message data. The message types for header
+ messages are defined in sections below.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Size of Header Message #n Data</p></td>
+ <td>
+ <p>This value specifies the number of bytes of header message
+ data following the header message type and length information for
+ the current message. The size includes padding bytes to make the
+ message a multiple of eight bytes.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Header Message #n Flags</p></td>
+ <td>
+ <p>This is a bit field with the following definition:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>If set, the message data is constant. This is used for
+ messages like the datatype message of a dataset.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>If set, the message is <em>shared</em> and stored in
+ another location than the object header. The Header Message Data
+ field contains a Shared Message (described in the <a
+ href="#ObjectHeaderMessages">Data Object Header Messages</a>
+ section below) and the Size of Header Message Data field contains
+ the size of that Shared Message.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>If set, the message should not be shared.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>If set, the HDF5 decoder should fail to open this object
+ if it does not understand the message&rsquo;s type and the file
+ is open with permissions allowing write access to the file.
+ (Normally, unknown messages can just be ignored by HDF5 decoders)
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>4</code></td>
+ <td>If set, the HDF5 decoder should set bit 5 of this
+ message&rsquo;s flags (in other words, this bit field) if it does
+ not understand the message&rsquo;s type and the object is
+ modified in any way. (Normally, unknown messages can just be
+ ignored by HDF5 decoders)</td>
+ </tr>
+ <tr>
+ <td align="center"><code>5</code></td>
+ <td>If set, this object was modified by software that did not
+ understand this message. (Normally, unknown messages should just
+ be ignored by HDF5 decoders) (Can be used to invalidate an index
+ or a similar feature)</td>
+ </tr>
+ <tr>
+ <td align="center"><code>6</code></td>
+ <td>If set, this message is shareable.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>7</code></td>
+ <td>If set, the HDF5 decoder should always fail to open this
+ object if it does not understand the message&rsquo;s type
+ (whether it is open for read-only or read-write access).
+ (Normally, unknown messages can just be ignored by HDF5 decoders)
+ </td>
+ </tr>
+ </table>
+ <p></p>
+
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Header Message #n Data</p></td>
+ <td>
+ <p>The format and length of this field is determined by the
+ header message type and size respectively. Some header message
+ types do not require any data and this information can be
+ eliminated by setting the length of the message to zero. The data
+ is padded with enough zeroes to make the size a multiple of eight.
+ </p>
+ </td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="V2ObjectHeaderPrefix"> IV.A.1.b. Version 2 Data Object
+ Header Prefix</a>
+</h4>
+
+<p>Note that the &ldquo;total number of messages&rdquo; field has
+ been dropped from the data object header prefix in this version. The
+ number of messages in the data object header is just determined by the
+ messages encountered in all the object header blocks.</p>
+
+<p>
+ Note also that the fields and messages in this version of data object
+ headers have <em>no</em> alignment or padding bytes inserted - they are
+ stored packed together.
+</p>
+
+<div align="center">
+ <table class="format">
+ <caption>Version 2 Object Header</caption>
+
+ <tr>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="4">Signature</td>
+ </tr>
+ <tr>
+ <td>Version</td>
+ <td>Flags</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Access time <em>(optional)</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Modification Time <em>(optional)</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Change Time <em>(optional)</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Birth Time <em>(optional)</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Maximum # of compact attributes <em>(optional)</em></td>
+ <td colspan="2">Minimum # of dense attributes <em>(optional)</em></td>
+ </tr>
+
+ <tr>
+ <td>Size of Chunk #0 <em>(variable size)</em></td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td>Header Message Type #1</td>
+ <td colspan="2">Size of Header Message Data #1</td>
+ <td>Header Message #1 Flags</td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Header Message #1 Creation Order <em>(optional)</em></td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Header Message Data #1<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
+
+ <tr>
+ <td>Header Message Type #n</td>
+ <td colspan="2">Size of Header Message Data #n</td>
+ <td>Header Message #n Flags</td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Header Message #n Creation Order <em>(optional)</em></td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Header Message Data #n<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Gap <em>(optional, variable size)</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Checksum</td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>OHDR</code>
+ &rdquo; is used to indicate the beginning of an object header. This
+ gives file consistency checking utilities a better chance of
+ reconstructing a damaged file.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>This field has a value of 2 indicating version 2 of the
+ object header.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Flags</p></td>
+ <td>
+ <p>This field is a bit field indicating additional information
+ about the object header.</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit(s)</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0-1</code></td>
+ <td>This two bit field determines the size of the <em>Size
+ of Chunk #0</em> field. The values are:
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>The <em>Size of Chunk #0</em> field is 1 byte.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>The <em>Size of Chunk #0</em> field is 2 bytes.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>The <em>Size of Chunk #0</em> field is 4 bytes.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>The <em>Size of Chunk #0</em> field is 8 bytes.
+ </td>
+ </tr>
+ </table>
+ <p></p>
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>If set, attribute creation order is tracked.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>If set, attribute creation order is indexed.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>4</code></td>
+ <td>If set, non-default attribute storage phase change values
+ are stored.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>5</code></td>
+ <td>If set, access, modification, change and birth times are
+ stored.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>6-7</code></td>
+ <td>Reserved</td>
+ </tr>
+ </table>
+ <p></p>
+
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Access Time</p></td>
+ <td>
+ <p>This 32-bit value represents the number of seconds after the
+ UNIX epoch when the object&rsquo;s raw data was last accessed (in
+ other words, read or written).</p>
+ <p>
+ This field is present if bit 5 of <em>flags</em> is set.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Modification Time</p></td>
+ <td>
+ <p>This 32-bit value represents the number of seconds after the
+ UNIX epoch when the object&rsquo;s raw data was last modified (in
+ other words, written).</p>
+ <p>
+ This field is present if bit 5 of <em>flags</em> is set.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Change Time</p></td>
+ <td>
+ <p>This 32-bit value represents the number of seconds after the
+ UNIX epoch when the object&rsquo;s metadata was last changed.</p>
+ <p>
+ This field is present if bit 5 of <em>flags</em> is set.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Birth Time</p></td>
+ <td>
+ <p>This 32-bit value represents the number of seconds after the
+ UNIX epoch when the object was created.</p>
+ <p>
+ This field is present if bit 5 of <em>flags</em> is set.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Maximum # of compact attributes</p></td>
+ <td>
+ <p>This is the maximum number of attributes to store in the
+ compact format before switching to the indexed format.</p>
+ <p>
+ This field is present if bit 4 of <em>flags</em> is set.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Minimum # of dense attributes</p></td>
+ <td>
+ <p>This is the minimum number of attributes to store in the
+ indexed format before switching to the compact format.</p>
+ <p>
+ This field is present if bit 4 of <em>flags</em> is set.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Size of Chunk #0</p></td>
+ <td>
+ <p>This unsigned value specifies the number of bytes of header
+ message data following this field that contain object header
+ information.</p>
+ <p>This value does not include the size of object header
+ continuation blocks for this object elsewhere in the file.</p>
+ <p>
+ The length of this field varies depending on bits 0 and 1 of the <em>flags</em>
+ field.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Header Message #n Type</p></td>
+ <td>
+ <p>Same format as version 1 of the object header, described
+ above.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Size of Header Message #n Data</p></td>
+ <td>
+ <p>
+ This value specifies the number of bytes of header message data
+ following the header message type and length information for the
+ current message. The size of messages in this version does <em>not</em>
+ include any padding bytes.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Header Message #n Flags</p></td>
+ <td>
+ <p>Same format as version 1 of the object header, described
+ above.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Header Message #n Creation Order</p></td>
+ <td>
+ <p>This field stores the order that a message of a given type
+ was created in.</p>
+ <p>
+ This field is present if bit 2 of <em>flags</em> is set.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Header Message #n Data</p></td>
+ <td>
+ <p>Same format as version 1 of the object header, described
+ above.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Gap</p></td>
+ <td>
+ <p>A gap in an object header chunk is inferred by the end of the
+ messages for the chunk before the beginning of the chunk&rsquo;s
+ checksum. Gaps are always smaller than the size of an object header
+ message prefix (message type + message size + message flags).</p>
+ <p>Gaps are formed when a message (typically an attribute
+ message) in an earlier chunk is deleted and a message from a later
+ chunk that does not quite fit into the free space is moved into the
+ earlier chunk.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Checksum</p></td>
+ <td>
+ <p>This is the checksum for the object header chunk.</p>
+ </td>
+ </tr>
+ </table>
+</div>
+
+<p>The header message types and the message data associated with
+ them compose the critical &ldquo;metadata&rdquo; about each object.
+ Some header messages are required for each object while others are
+ optional. Some optional header messages may also be repeated several
+ times in the header itself, the requirements and number of times
+ allowed in the header will be noted in each header message description
+ below.</p>
+
+
+<br />
+<h3>
+ <a name="ObjectHeaderMessages"> IV.A.2. Disk Format: Level 2A2 -
+ Data Object Header Messages</a>
+</h3>
+
+<p>Data object header messages are small pieces of metadata that are
+ stored in the data object header for each object in an HDF5 file. Data
+ object header messages provide the metadata required to describe an
+ object and its contents, as well as optional pieces of metadata that
+ annotate the meaning or purpose of the object.</p>
+
+<p>
+ Data object header messages are either stored directly in the data
+ object header for the object or are shared between multiple objects in
+ the file. When a message is shared, a flag in the <em>Message
+ Flags</em> indicates that the actual <em>Message Data</em> portion of that
+ message is stored in another location (such as another data object
+ header, or a heap in the file) and the <em>Message Data</em> field
+ contains the information needed to locate the actual information for
+ the message.
+</p>
+
+<p>The format of shared message data is described here:</p>
+
+<div align="center">
+ <table class="format">
+ <caption>Shared Message (Version 1)</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td>Type</td>
+ <td colspan="2">Reserved (zero)</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Reserved (zero)</td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
+
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number is used when there are changes in
+ the format of a shared object message and is described here:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Never used.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>Used by the library before version 1.6.1.</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Type</p></td>
+ <td><p>The type of shared message location:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Message stored in another object&rsquo;s header (a <em>committed</em>
+ message).
+ </td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Address</p></td>
+ <td><p>The address of the object header containing the
+ message to be shared.</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Shared Message (Version 2)</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td>Type</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number is used when there are changes in
+ the format of a shared object message and is described here:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>Used by the library of version 1.6.1 and after.</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Type</p></td>
+ <td><p>The type of shared message location:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Message stored in another object&rsquo;s header (a <em>committed</em>
+ message).
+ </td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Address</p></td>
+ <td><p>The address of the object header containing the
+ message to be shared.</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Shared Message (Version 3)</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td>Type</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Location <em>(variable size)</em></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number indicates changes in the format of
+ shared object message and is described here:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>Used by the library of version 1.8 and after. In this
+ version, the <em>Type</em> field can indicate that the message is
+ stored in the fractal heap.
+ </td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Type</p></td>
+ <td><p>The type of shared message location:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Message is not shared and is not shareable.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>Message stored in file&rsquo;s <em>shared object
+ header message</em> heap (a <em>shared</em> message).
+ </td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>Message stored in another object&rsquo;s header (a <em>committed</em>
+ message).
+ </td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>Message stored is not shared, but is shareable.</td>
+ </tr>
+
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Location</p></td>
+ <td><p>
+ This field contains either a <em>Size of Offsets</em>-bytes address
+ of the object header containing the message to be shared, or an
+ 8-byte fractal heap ID for the message in the file&rsquo;s <em>shared
+ object header message</em> heap.
+ </p></td>
+ </tr>
+ </table>
+</div>
+
+
+<p>The following is a list of currently defined header messages:</p>
+
+<br />
+<h4>
+ <a name="NILMessage">IV.A.2.a. The NIL Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> NIL</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0000</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may be repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>The NIL message is used to indicate a message which is to be
- ignored when reading the header messages for a data object.
- [Possibly one which has been deleted for some reason.]
- </td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> Unspecified</td></tr>
- </table></center>
- <!-- end msgdesc table -->
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> NIL</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0000</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>The NIL message is used to indicate a message which is to be
+ ignored when reading the header messages for a data object.
+ [Possibly one which has been deleted for some reason.]</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> Unspecified</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
<br />
-<h4><a name="DataspaceMessage">IV.A.2.b. The Dataspace Message</a></h4>
+<h4>
+ <a name="DataspaceMessage">IV.A.2.b. The Dataspace Message</a>
+</h4>
- <!-- start msgdesc table -->
- <center>
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Dataspace</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0001</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies according to the number of
- dimensions, as described in the following table.</td></tr>
- <tr><td colspan="2"><b>Status:</b> Required for dataset objects;
- may not be repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>The dataspace message describes the number of dimensions (in
- other words, &ldquo;rank&rdquo;) and size of each dimension that
- the data object has. This message is only used for datasets which
- have a simple, rectilinear, array-like layout; datasets requiring
- a more complex layout are not yet supported.
- </td>
- </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Dataspace</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0001</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies according to the number of
+ dimensions, as described in the following table.</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Required for dataset objects; may
+ not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>The dataspace message describes the number of dimensions (in
+ other words, &ldquo;rank&rdquo;) and size of each dimension that the
+ data object has. This message is only used for datasets which have a
+ simple, rectilinear, array-like layout; datasets requiring a more
+ complex layout are not yet supported.</td>
+ </tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Dataspace Message - Version 1
- </caption>
-
- <tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Dimensionality</td>
- <td>Flags</td>
- <td>Reserved</td>
- </tr>
-
- <tr>
- <td colspan="4">Reserved</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Dimension #1 Size<sup>L</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Dimension #n Size<sup>L</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Dimension #1 Maximum Size<sup>L</sup> <em>(optional)</em><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Dimension #n Maximum Size<sup>L</sup> <em>(optional)</em><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Permutation Index #1<sup>L</sup> <em>(optional)</em><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Permutation Index #n<sup>L</sup> <em>(optional)</em><br /><br /></td>
- </tr>
- </table>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
+
+<div align="center">
+ <table class="format">
+ <caption>Dataspace Message - Version 1</caption>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
- </div>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td>
- <p>This value is used to determine the format of the
- Dataspace Message. When the format of the
- information in the message is changed, the version number
- is incremented and can be used to determine how the
- information in the object header is formatted. This
- document describes version one (1) (there was no version
- zero (0)).
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimensionality</p></td>
- <td>
- <p>This value is the number of dimensions that the data
- object has.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Flags</p></td>
- <td>
- <p>This field is used to store flags to indicate the
- presence of parts of this message. Bit 0 (the least
- significant bit) is used to indicate that maximum
- dimensions are present. Bit 1 is used to indicate that
- permutation indices are present.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimension #n Size</p></td>
- <td>
- <p>This value is the current size of the dimension of the
- data as stored in the file. The first dimension stored in
- the list of dimensions is the slowest changing dimension
- and the last dimension stored is the fastest changing
- dimension.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimension #n Maximum Size</p></td>
- <td>
- <p>This value is the maximum size of the dimension of the
- data as stored in the file. This value may be the special
- &ldquo;<a href="#UnlimitedDim">unlimited</a>&rdquo; size which indicates
- that the data may expand along this dimension indefinitely.
- If these values are not stored, the maximum size of each
- dimension is assumed to be the dimension&rsquo;s current size.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Permutation Index #n</p></td>
- <td>
- <p>This value is the index permutation used to map
- each dimension from the canonical representation to an
- alternate axis for each dimension. If these values are
- not stored, the first dimension stored in the list of
- dimensions is the slowest changing dimension and the last
- dimension stored is the fastest changing dimension.
- </p>
- </td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td>Version</td>
+ <td>Dimensionality</td>
+ <td>Flags</td>
+ <td>Reserved</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Reserved</td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Dimension #1 Size<sup>L</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Dimension #n Size<sup>L</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Dimension #1 Maximum Size<sup>L</sup> <em>(optional)</em><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Dimension #n Maximum Size<sup>L</sup> <em>(optional)</em><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Permutation Index #1<sup>L</sup> <em>(optional)</em><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Permutation Index #n<sup>L</sup> <em>(optional)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;L&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Lengths&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
+</div>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <br />
- <p>Version 2 of the dataspace message dropped the optional
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>This value is used to determine the format of the Dataspace
+ Message. When the format of the information in the message is
+ changed, the version number is incremented and can be used to
+ determine how the information in the object header is formatted.
+ This document describes version one (1) (there was no version zero
+ (0)).</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Dimensionality</p></td>
+ <td>
+ <p>This value is the number of dimensions that the data object
+ has.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Flags</p></td>
+ <td>
+ <p>This field is used to store flags to indicate the presence of
+ parts of this message. Bit 0 (the least significant bit) is used to
+ indicate that maximum dimensions are present. Bit 1 is used to
+ indicate that permutation indices are present.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Dimension #n Size</p></td>
+ <td>
+ <p>This value is the current size of the dimension of the data
+ as stored in the file. The first dimension stored in the list of
+ dimensions is the slowest changing dimension and the last dimension
+ stored is the fastest changing dimension.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Dimension #n Maximum Size</p></td>
+ <td>
+ <p>
+ This value is the maximum size of the dimension of the data as
+ stored in the file. This value may be the special &ldquo;<a
+ href="#UnlimitedDim">unlimited</a>&rdquo; size which indicates
+ that the data may expand along this dimension indefinitely. If
+ these values are not stored, the maximum size of each dimension is
+ assumed to be the dimension&rsquo;s current size.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Permutation Index #n</p></td>
+ <td>
+ <p>This value is the index permutation used to map each
+ dimension from the canonical representation to an alternate axis
+ for each dimension. If these values are not stored, the first
+ dimension stored in the list of dimensions is the slowest changing
+ dimension and the last dimension stored is the fastest changing
+ dimension.</p>
+ </td>
+ </tr>
+ </table>
+</div>
+
+
+
+<br />
+<p>Version 2 of the dataspace message dropped the optional
permutation index value support, as it was never implemented in the
HDF5 Library:</p>
- <div align="center">
- <table class="format">
- <caption>
- Dataspace Message - Version 2
- </caption>
-
- <tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Dimensionality</td>
- <td>Flags</td>
- <td>Type</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Dimension #1 Size<sup>L</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Dimension #n Size<sup>L</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Dimension #1 Maximum Size<sup>L</sup> <em>(optional)</em><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Dimension #n Maximum Size<sup>L</sup> <em>(optional)</em><br /><br /></td>
- </tr>
- </table>
+<div align="center">
+ <table class="format">
+ <caption>Dataspace Message - Version 2</caption>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
- </div>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td>
- <p>This value is used to determine the format of the
- Dataspace Message. This field should be &lsquo;2&rsquo; for version 2
- format messages.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimensionality</p></td>
- <td>
- <p>This value is the number of dimensions that the data object has.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Flags</p></td>
- <td>
- <p>This field is used to store flags to indicate the
- presence of parts of this message. Bit 0 (the least
- significant bit) is used to indicate that maximum
- dimensions are present.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Type</p></td>
- <td>
- <p>This field indicates the type of the dataspace:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>A <em>scalar</em> dataspace; in other words,
- a dataspace with a single, dimensionless element.
- </td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td>A <em>simple</em> dataspace; in other words,
- a dataspace with a rank > 0 and an appropriate # of
- dimensions.
- </td>
- </tr>
- <tr>
- <td align="center"><code>2</code></td>
- <td>A <em>null</em> dataspace; in other words,
- a dataspace with no elements.
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimension #n Size</p></td>
- <td>
- <p>This value is the current size of the dimension of the
- data as stored in the file. The first dimension stored in
- the list of dimensions is the slowest changing dimension
- and the last dimension stored is the fastest changing
- dimension.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimension #n Maximum Size</p></td>
- <td>
- <p>This value is the maximum size of the dimension of the
- data as stored in the file. This value may be the special
- &ldquo;<a href="#UnlimitedDim">unlimited</a>&rdquo; size which indicates
- that the data may expand along this dimension indefinitely.
- If these values are not stored, the maximum size of each
- dimension is assumed to be the dimension&rsquo;s current size.
- </p>
- </td>
- </tr>
+ <tr>
+ <td>Version</td>
+ <td>Dimensionality</td>
+ <td>Flags</td>
+ <td>Type</td>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4"><br />Dimension #1 Size<sup>L</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Dimension #n Size<sup>L</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Dimension #1 Maximum Size<sup>L</sup> <em>(optional)</em><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Dimension #n Maximum Size<sup>L</sup> <em>(optional)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;L&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Lengths&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>This value is used to determine the format of the Dataspace
+ Message. This field should be &lsquo;2&rsquo; for version 2 format
+ messages.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Dimensionality</p></td>
+ <td>
+ <p>This value is the number of dimensions that the data object
+ has.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Flags</p></td>
+ <td>
+ <p>This field is used to store flags to indicate the presence of
+ parts of this message. Bit 0 (the least significant bit) is used to
+ indicate that maximum dimensions are present.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Type</p></td>
+ <td>
+ <p>This field indicates the type of the dataspace:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>A <em>scalar</em> dataspace; in other words, a dataspace
+ with a single, dimensionless element.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>A <em>simple</em> dataspace; in other words, a dataspace
+ with a rank > 0 and an appropriate # of dimensions.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>A <em>null</em> dataspace; in other words, a dataspace
+ with no elements.
+ </td>
+ </tr>
+ </table>
+ <p></p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Dimension #n Size</p></td>
+ <td>
+ <p>This value is the current size of the dimension of the data
+ as stored in the file. The first dimension stored in the list of
+ dimensions is the slowest changing dimension and the last dimension
+ stored is the fastest changing dimension.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Dimension #n Maximum Size</p></td>
+ <td>
+ <p>
+ This value is the maximum size of the dimension of the data as
+ stored in the file. This value may be the special &ldquo;<a
+ href="#UnlimitedDim">unlimited</a>&rdquo; size which indicates
+ that the data may expand along this dimension indefinitely. If
+ these values are not stored, the maximum size of each dimension is
+ assumed to be the dimension&rsquo;s current size.
+ </p>
+ </td>
+ </tr>
+
+ </table>
+</div>
@@ -8287,22 +8431,22 @@ IV.A.2. Disk Format: Level 2A2 - Data Object Header Messages</a></h3>
<center>
<table border cellpadding="4" width="80%">
- <caption align="bottom">
- <b>HDF5 Dataspace Message Layout</b>
- </caption>
-
- <tr align="center">
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
+ <caption align="bottom">
+ <b>HDF5 Dataspace Message Layout</b>
+ </caption>
+
+ <tr align="center">
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
</tr>
- <tr align="center">
- <td colspan="4">Mesh Type</td>
+ <tr align="center">
+ <td colspan="4">Mesh Type</td>
</tr>
- <tr align="center">
- <td colspan="4">Logical Dimensionality</td>
+ <tr align="center">
+ <td colspan="4">Logical Dimensionality</td>
</tr>
</table>
</center>
@@ -8311,156 +8455,156 @@ IV.A.2. Disk Format: Level 2A2 - Data Object Header Messages</a></h3>
<dl>
<dt>The elements of the dimensionality message are described below:
<dd>
- <dl>
- <dt>Mesh Type: (unsigned 32-bit integer)
- <dd>This value indicates whether the grid is
- polar/spherical/cartesion,
- structured/unstructured and regular/irregular. <br />
- The mesh type value is broken up as follows: <br />
-
- <br />
- <center>
- <table border cellpadding="4" width="80%">
- <caption align="bottom">
- <b>HDF5 Mesh-type Layout</b>
- </caption>
-
- <tr align="center">
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr align="center">
- <td colspan="1">Mesh Embedding</td>
- <td colspan="1">Coordinate System</td>
- <td colspan="1">Structure</td>
- <td colspan="1">Regularity</td>
- </tr>
- </table>
- </center>
- The following are the definitions of mesh-type bytes:
- <dl>
- <dt>Mesh Embedding
- <dd>This value indicates whether the dataset dataspace
- is located within
- another dataspace or not:
- <dl> <dl>
- <dt>&lt;STANDALONE&gt;
- <dd>The dataset mesh is self-contained and is not
- embedded in another mesh.
- <dt>&lt;EMBEDDED&gt;
- <dd>The dataset&rsquo;s dataspace is located within
- another dataspace, as
- described in information below.
- </dl> </dl>
- <dt>Coordinate System
- <dd>This value defines the type of coordinate system
- used for the mesh:
- <dl> <dl>
- <dt>&lt;POLAR&gt;
- <dd>The last two dimensions are in polar
- coordinates, higher dimensions are
- cartesian.
- <dt>&lt;SPHERICAL&gt;
- <dd>The last three dimensions are in spherical
- coordinates, higher dimensions
- are cartesian.
- <dt>&lt;CARTESIAN&gt;
- <dd>All dimensions are in cartesian coordinates.
- </dl> </dl>
- <dt>Structure
- <dd>This value defines the locations of the grid-points
- on the axes:
- <dl> <dl>
- <dt>&lt;STRUCTURED&gt;
- <dd>All grid-points are on integral, sequential
- locations, starting from 0.
- <dt>&lt;UNSTRUCTURED&gt;
- <dd>Grid-points locations in each dimension are
- explicitly defined and
- may be of any numeric datatype.
- </dl> </dl>
- <dt>Regularity
- <dd>This value defines the locations of the dataset
- points on the grid:
- <dl> <dl>
- <dt>&lt;REGULAR&gt;
- <dd>All dataset elements are located at the
- grid-points defined.
- <dt>&lt;IRREGULAR&gt;
- <dd>Each dataset element has a particular
- grid-location defined.
- </dl> </dl>
- </dl>
- <p>The following grid combinations are currently allowed:</p>
- <dl> <dl>
- <dt>&lt;POLAR-STRUCTURED-REGULAR&gt;
- <dt>&lt;SPHERICAL-STRUCTURED-REGULAR&gt;
- <dt>&lt;CARTESIAN-STRUCTURED-REGULAR&gt;
- <dt>&lt;POLAR-UNSTRUCTURED-REGULAR&gt;
- <dt>&lt;SPHERICAL-UNSTRUCTURED-REGULAR&gt;
- <dt>&lt;CARTESIAN-UNSTRUCTURED-REGULAR&gt;
- <dt>&lt;CARTESIAN-UNSTRUCTURED-IRREGULAR&gt;
- </dl> </dl>
- All of the above grid types can be embedded within another
- dataspace.
- <br /> <br />
- <dt>Logical Dimensionality: (unsigned 32-bit integer)
- <dd>This value is the number of dimensions that the dataset occupies.
-
- <br />
- <center>
- <table border cellpadding="4" width="80%">
- <caption align="bottom">
- <b>HDF5 Dataspace Embedded Dimensionality Information</b>
- </caption>
-
- <tr align="center">
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr align="center">
- <td colspan="4">Embedded Dimensionality</td>
- </tr>
- <tr align="center">
- <td colspan="4">Embedded Dimension Size #1</td>
- </tr>
- <tr align="center">
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
- <tr align="center">
- <td colspan="4">Embedded Dimension Size #n</td>
- </tr>
- <tr align="center">
- <td colspan="4">Embedded Origin Location #1</td>
- </tr>
- <tr align="center">
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
- <tr align="center">
- <td colspan="4">Embedded Origin Location #n</td>
- </tr>
- </table>
- </center>
-
- <dt>Embedded Dimensionality: (unsigned 32-bit integer)
- <dd>This value is the number of dimensions of the space the
- dataset is located within: in other words, a planar dataset
+ <dl>
+ <dt>Mesh Type: (unsigned 32-bit integer)
+ <dd>This value indicates whether the grid is
+ polar/spherical/cartesion,
+ structured/unstructured and regular/irregular. <br />
+ The mesh type value is broken up as follows: <br />
+
+ <br />
+ <center>
+ <table border cellpadding="4" width="80%">
+ <caption align="bottom">
+ <b>HDF5 Mesh-type Layout</b>
+ </caption>
+
+ <tr align="center">
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr align="center">
+ <td colspan="1">Mesh Embedding</td>
+ <td colspan="1">Coordinate System</td>
+ <td colspan="1">Structure</td>
+ <td colspan="1">Regularity</td>
+ </tr>
+ </table>
+ </center>
+ The following are the definitions of mesh-type bytes:
+ <dl>
+ <dt>Mesh Embedding
+ <dd>This value indicates whether the dataset dataspace
+ is located within
+ another dataspace or not:
+ <dl> <dl>
+ <dt>&lt;STANDALONE&gt;
+ <dd>The dataset mesh is self-contained and is not
+ embedded in another mesh.
+ <dt>&lt;EMBEDDED&gt;
+ <dd>The dataset&rsquo;s dataspace is located within
+ another dataspace, as
+ described in information below.
+ </dl> </dl>
+ <dt>Coordinate System
+ <dd>This value defines the type of coordinate system
+ used for the mesh:
+ <dl> <dl>
+ <dt>&lt;POLAR&gt;
+ <dd>The last two dimensions are in polar
+ coordinates, higher dimensions are
+ cartesian.
+ <dt>&lt;SPHERICAL&gt;
+ <dd>The last three dimensions are in spherical
+ coordinates, higher dimensions
+ are cartesian.
+ <dt>&lt;CARTESIAN&gt;
+ <dd>All dimensions are in cartesian coordinates.
+ </dl> </dl>
+ <dt>Structure
+ <dd>This value defines the locations of the grid-points
+ on the axes:
+ <dl> <dl>
+ <dt>&lt;STRUCTURED&gt;
+ <dd>All grid-points are on integral, sequential
+ locations, starting from 0.
+ <dt>&lt;UNSTRUCTURED&gt;
+ <dd>Grid-points locations in each dimension are
+ explicitly defined and
+ may be of any numeric datatype.
+ </dl> </dl>
+ <dt>Regularity
+ <dd>This value defines the locations of the dataset
+ points on the grid:
+ <dl> <dl>
+ <dt>&lt;REGULAR&gt;
+ <dd>All dataset elements are located at the
+ grid-points defined.
+ <dt>&lt;IRREGULAR&gt;
+ <dd>Each dataset element has a particular
+ grid-location defined.
+ </dl> </dl>
+ </dl>
+ <p>The following grid combinations are currently allowed:</p>
+ <dl> <dl>
+ <dt>&lt;POLAR-STRUCTURED-REGULAR&gt;
+ <dt>&lt;SPHERICAL-STRUCTURED-REGULAR&gt;
+ <dt>&lt;CARTESIAN-STRUCTURED-REGULAR&gt;
+ <dt>&lt;POLAR-UNSTRUCTURED-REGULAR&gt;
+ <dt>&lt;SPHERICAL-UNSTRUCTURED-REGULAR&gt;
+ <dt>&lt;CARTESIAN-UNSTRUCTURED-REGULAR&gt;
+ <dt>&lt;CARTESIAN-UNSTRUCTURED-IRREGULAR&gt;
+ </dl> </dl>
+ All of the above grid types can be embedded within another
+ dataspace.
+ <br /> <br />
+ <dt>Logical Dimensionality: (unsigned 32-bit integer)
+ <dd>This value is the number of dimensions that the dataset occupies.
+
+ <br />
+ <center>
+ <table border cellpadding="4" width="80%">
+ <caption align="bottom">
+ <b>HDF5 Dataspace Embedded Dimensionality Information</b>
+ </caption>
+
+ <tr align="center">
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr align="center">
+ <td colspan="4">Embedded Dimensionality</td>
+ </tr>
+ <tr align="center">
+ <td colspan="4">Embedded Dimension Size #1</td>
+ </tr>
+ <tr align="center">
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
+ <tr align="center">
+ <td colspan="4">Embedded Dimension Size #n</td>
+ </tr>
+ <tr align="center">
+ <td colspan="4">Embedded Origin Location #1</td>
+ </tr>
+ <tr align="center">
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
+ <tr align="center">
+ <td colspan="4">Embedded Origin Location #n</td>
+ </tr>
+ </table>
+ </center>
+
+ <dt>Embedded Dimensionality: (unsigned 32-bit integer)
+ <dd>This value is the number of dimensions of the space the
+ dataset is located within: in other words, a planar dataset
located within a 3-D space, a 3-D dataset
- which is a subset of another 3-D space, and so on.
- <dt>Embedded Dimension Size: (unsigned 32-bit integer)
- <dd>These values are the sizes of the dimensions of the
- embedded dataspace
- that the dataset is located within.
- <dt>Embedded Origin Location: (unsigned 32-bit integer)
- <dd>These values comprise the location of the dataset&rsquo;s
- origin within the embedded dataspace.
- </dl>
+ which is a subset of another 3-D space, and so on.
+ <dt>Embedded Dimension Size: (unsigned 32-bit integer)
+ <dd>These values are the sizes of the dimensions of the
+ embedded dataspace
+ that the dataset is located within.
+ <dt>Embedded Origin Location: (unsigned 32-bit integer)
+ <dd>These values comprise the location of the dataset&rsquo;s
+ origin within the embedded dataspace.
+ </dl>
</dl>
[Comment: need some way to handle different orientations of the
dataset dataspace
@@ -8469,31 +8613,31 @@ IV.A.2. Disk Format: Level 2A2 - Data Object Header Messages</a></h3>
<br />
<center>
<table border cellpadding="4" width="80%">
- <caption align="bottom">
- <b>HDF5 Dataspace Structured/Regular Grid Information</b>
- </caption>
-
- <tr align="center">
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
+ <caption align="bottom">
+ <b>HDF5 Dataspace Structured/Regular Grid Information</b>
+ </caption>
+
+ <tr align="center">
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
</tr>
- <tr align="center">
- <td colspan="4">Logical Dimension Size #1</td>
+ <tr align="center">
+ <td colspan="4">Logical Dimension Size #1</td>
</tr>
- <tr align="center">
- <td colspan="4">Logical Dimension Maximum #1</td>
+ <tr align="center">
+ <td colspan="4">Logical Dimension Maximum #1</td>
</tr>
- <tr align="center">
- <td colspan="4">.<br />.<br />.<br /></td>
+ <tr align="center">
+ <td colspan="4">.<br />.<br />.<br /></td>
</tr>
- <tr align="center">
- <td colspan="4">Logical Dimension Size #n</td>
+ <tr align="center">
+ <td colspan="4">Logical Dimension Size #n</td>
</tr>
- <tr align="center">
- <td colspan="4">Logical Dimension Maximum #n</td>
+ <tr align="center">
+ <td colspan="4">Logical Dimension Maximum #n</td>
</tr>
</table>
</center>
@@ -8502,58 +8646,58 @@ IV.A.2. Disk Format: Level 2A2 - Data Object Header Messages</a></h3>
<dl>
<dt>The elements of the dimensionality message are described below:
<dd>
- <dl>
- <dt>Logical Dimension Size #n: (unsigned 32-bit integer)
- <dd>This value is the current size of the dimension of the
- data as stored in
- the file. The first dimension stored in the list of
- dimensions is the slowest
- changing dimension and the last dimension stored is the
- fastest changing
- dimension.
- <dt>Logical Dimension Maximum #n: (unsigned 32-bit integer)
- <dd>This value is the maximum size of the dimension of the
- data as stored in
- the file. This value may be the special value
- &lt;UNLIMITED&gt; which
- indicates that the data may expand along this dimension
- indefinitely.
- </dl>
+ <dl>
+ <dt>Logical Dimension Size #n: (unsigned 32-bit integer)
+ <dd>This value is the current size of the dimension of the
+ data as stored in
+ the file. The first dimension stored in the list of
+ dimensions is the slowest
+ changing dimension and the last dimension stored is the
+ fastest changing
+ dimension.
+ <dt>Logical Dimension Maximum #n: (unsigned 32-bit integer)
+ <dd>This value is the maximum size of the dimension of the
+ data as stored in
+ the file. This value may be the special value
+ &lt;UNLIMITED&gt; which
+ indicates that the data may expand along this dimension
+ indefinitely.
+ </dl>
</dl>
<br />
<center>
<table border cellpadding="4" width="80%">
- <caption align="bottom">
- <b>HDF5 Dataspace Structured/Irregular Grid Information</b>
- </caption>
-
- <tr align="center">
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
+ <caption align="bottom">
+ <b>HDF5 Dataspace Structured/Irregular Grid Information</b>
+ </caption>
+
+ <tr align="center">
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
</tr>
- <tr align="center">
- <td colspan="4"># of Grid Points in Dimension #1</td>
+ <tr align="center">
+ <td colspan="4"># of Grid Points in Dimension #1</td>
</tr>
- <tr align="center">
- <td colspan="4">.<br />.<br />.<br /></td>
+ <tr align="center">
+ <td colspan="4">.<br />.<br />.<br /></td>
</tr>
- <tr align="center">
- <td colspan="4"># of Grid Points in Dimension #n</td>
+ <tr align="center">
+ <td colspan="4"># of Grid Points in Dimension #n</td>
</tr>
- <tr align="center">
- <td colspan="4">Datatype of Grid Point Locations</td>
+ <tr align="center">
+ <td colspan="4">Datatype of Grid Point Locations</td>
</tr>
- <tr align="center">
- <td colspan="4">Location of Grid Points in Dimension #1</td>
+ <tr align="center">
+ <td colspan="4">Location of Grid Points in Dimension #1</td>
</tr>
- <tr align="center">
- <td colspan="4">.<br />.<br />.<br /></td>
+ <tr align="center">
+ <td colspan="4">.<br />.<br />.<br /></td>
</tr>
- <tr align="center">
- <td colspan="4">Location of Grid Points in Dimension #n</td>
+ <tr align="center">
+ <td colspan="4">Location of Grid Points in Dimension #n</td>
</tr>
</table>
</center>
@@ -8561,6342 +8705,6548 @@ IV.A.2. Disk Format: Level 2A2 - Data Object Header Messages</a></h3>
<br />
<center>
<table border cellpadding="4" width="80%">
- <caption align="bottom">
- <b>HDF5 Dataspace Unstructured Grid Information</b>
- </caption>
-
- <tr align="center">
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
+ <caption align="bottom">
+ <b>HDF5 Dataspace Unstructured Grid Information</b>
+ </caption>
+
+ <tr align="center">
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
</tr>
- <tr align="center">
- <td colspan="4"># of Grid Points</td>
+ <tr align="center">
+ <td colspan="4"># of Grid Points</td>
</tr>
- <tr align="center">
- <td colspan="4">Datatype of Grid Point Locations</td>
+ <tr align="center">
+ <td colspan="4">Datatype of Grid Point Locations</td>
</tr>
- <tr align="center">
- <td colspan="4">Grid Point Locations<br />.<br />.<br /></td>
+ <tr align="center">
+ <td colspan="4">Grid Point Locations<br />.<br />.<br /></td>
</tr>
</table>
</center>
-->
<br />
-<h4><a name="LinkInfoMessage">IV.A.2.c. The Link Info Message</a></h4>
+<h4>
+ <a name="LinkInfoMessage">IV.A.2.c. The Link Info Message</a>
+</h4>
- <!-- start msgdesc table -->
- <center>
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Link Info</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x002 </td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies </td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated. </td></tr>
- <tr><td><b>Description:</b></td>
- <td>The link info message tracks variable information about the
- current state of the links for a &ldquo;new style&rdquo;
- group&rsquo;s behavior. Variable information will be stored in
- this message and constant information will be stored in the
- <a href="#GroupInfoMessage">Group Info</a> message.
- </td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Link Info
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Flags</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Maximum Creation Index <em>(8 bytes, optional)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Fractal Heap Address<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Address of v2 B-tree for Name Index<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Address of v2 B-tree for Creation Order Index<sup>O</sup> <em>(optional)</em><br /><br /></td>
- </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Link Info</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x002</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>The link info message tracks variable information about the
+ current state of the links for a &ldquo;new style&rdquo;
+ group&rsquo;s behavior. Variable information will be stored in this
+ message and constant information will be stored in the <a
+ href="#GroupInfoMessage">Group Info</a> message.
+ </td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- </table>
+<div align="center">
+ <table class="format">
+ <caption>Link Info</caption>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
- </div>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td>
- <p>The version number for this message. This document describes
- version 0.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Flags</p></td>
- <td><p>This field determines various optional aspects of the link
- info message:
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>If set, creation order for the links is tracked.
- </td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td>If set, creation order for the links is indexed.
- </td>
- </tr>
- <tr>
- <td align="center"><code>2-7</code></td>
- <td>Reserved</td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>Maximum Creation Index</p></td>
- <td><p>This 64-bit value is the maximum creation order index value
- stored for a link in this group.</p>
- <p>This field is present if bit 0 of <em>flags</em> is set.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Fractal Heap Address</p></td>
- <td>
- <p>
- This is the address of the fractal heap to store dense links.
- Each link stored in the fractal heap is stored as a
- <a href="#LinkMessage">Link Message</a>.
- </p>
- <p>
- If there are no links in the group, or the group&rsquo;s links
- are stored &ldquo;compactly&rdquo; (as object header messages), this
- value will be the <a href="#UndefinedAddress">undefined
- address</a>.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Address of v2 B-tree for Name Index</p></td>
- <td><p>This is the address of the version 2 B-tree to index names of links.</p>
- <p>If there are no links in the group, or the group&rsquo;s links
- are stored &ldquo;compactly&rdquo; (as object header messages), this
- value will be the <a href="#UndefinedAddress">undefined
- address</a>.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Address of v2 B-tree for Creation Order Index</p></td>
- <td><p>This is the address of the version 2 B-tree to index creation order of links.</p>
- <p>If there are no links in the group, or the group&rsquo;s links
- are stored &ldquo;compactly&rdquo; (as object header messages), this
- value will be the <a href="#UndefinedAddress">undefined
- address</a>.
- </p>
- <p>This field exists if bit 1 of <em>flags</em> is set.</p>
- </td>
- </tr>
+ <tr>
+ <td>Version</td>
+ <td>Flags</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4"><br />Maximum Creation Index <em>(8 bytes,
+ optional)</em><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Fractal Heap Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Address of v2 B-tree for Name Index<sup>O</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Address of v2 B-tree for Creation Order
+ Index<sup>O</sup> <em>(optional)</em><br />
+ <br /></td>
+ </tr>
+
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="DatatypeMessage">IV.A.2.d. The Datatype Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
- <table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Datatype</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0003
- </td></tr>
- <tr><td colspan="2"><b>Length:</b> Variable</td></tr>
- <tr><td colspan="2"><b>Status:</b> Required for dataset or committed
- datatype (formerly named datatype) objects; may not be repeated.
- </td></tr>
- <tr><td><b>Description:</b></td>
- <td><p>The datatype message defines the datatype for each element
- of a dataset or a common datatype for sharing between multiple
- datasets. A datatype can describe an atomic type like a fixed-
- or floating-point type or more complex types like a C struct
- (compound datatype), array (array datatype) or C++ vector
- (variable-length datatype).</p>
- <p>Datatype messages that are part of a dataset object do not
- describe how elements are related to one another; the dataspace
- message is used for that purpose. Datatype messages that are part of
- a committed datatype (formerly named datatype) message describe
- a common datatype that can be shared by multiple datasets in the
- file.</p>
- </td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Datatype Message
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Class and Version</td>
- <td>Class Bit Field, Bits 0-7</td>
- <td>Class Bit Field, Bits 8-15</td>
- <td>Class Bit Field, Bits 16-23</td>
- </tr>
-
- <tr>
- <td colspan="4">Size</td>
- </tr>
-
- <tr>
- <td colspan="4"><br /><br />Properties<br /><br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>The version number for this message. This document describes
+ version 0.</p>
+ </td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Class and Version</p></td>
- <td>
- <p>The version of the datatype message and the datatype&rsquo;s class
- information are packed together in this field. The version
- number is packed in the top 4 bits of the field and the class
- is contained in the bottom 4 bits.
- </p>
- <p>The version number information is used for changes in the
- format of the datatype message and is described here:
+ <tr>
+ <td><p>Flags</p></td>
+ <td><p>This field determines various optional aspects of the
+ link info message:</p>
<table class="list">
<tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
</tr>
<tr>
- <td align="center"><code>0</code></td>
- <td>Never used
- </td>
+ <td align="center"><code>0</code></td>
+ <td>If set, creation order for the links is tracked.</td>
</tr>
<tr>
- <td align="center"><code>1</code></td>
- <td>Used by early versions of the library to encode
- compound datatypes with explicit array fields.
- See the compound datatype description below for
- further details.
- </td>
+ <td align="center"><code>1</code></td>
+ <td>If set, creation order for the links is indexed.</td>
</tr>
<tr>
- <td align="center"><code>2</code></td>
- <td>Used when an array datatype needs to be encoded.
- </td>
+ <td align="center"><code>2-7</code></td>
+ <td>Reserved</td>
</tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Maximum Creation Index</p></td>
+ <td><p>This 64-bit value is the maximum creation order index
+ value stored for a link in this group.</p>
+ <p>
+ This field is present if bit 0 of <em>flags</em> is set.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Fractal Heap Address</p></td>
+ <td>
+ <p>
+ This is the address of the fractal heap to store dense links. Each
+ link stored in the fractal heap is stored as a <a
+ href="#LinkMessage">Link Message</a>.
+ </p>
+ <p>
+ If there are no links in the group, or the group&rsquo;s links are
+ stored &ldquo;compactly&rdquo; (as object header messages), this
+ value will be the <a href="#UndefinedAddress">undefined address</a>.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Address of v2 B-tree for Name Index</p></td>
+ <td><p>This is the address of the version 2 B-tree to index
+ names of links.</p>
+ <p>
+ If there are no links in the group, or the group&rsquo;s links are
+ stored &ldquo;compactly&rdquo; (as object header messages), this
+ value will be the <a href="#UndefinedAddress">undefined address</a>.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Address of v2 B-tree for Creation Order Index</p></td>
+ <td><p>This is the address of the version 2 B-tree to index
+ creation order of links.</p>
+ <p>
+ If there are no links in the group, or the group&rsquo;s links are
+ stored &ldquo;compactly&rdquo; (as object header messages), this
+ value will be the <a href="#UndefinedAddress">undefined address</a>.
+ </p>
+ <p>
+ This field exists if bit 1 of <em>flags</em> is set.
+ </p></td>
+ </tr>
+
+ </table>
+</div>
+
+
+<br />
+<h4>
+ <a name="DatatypeMessage">IV.A.2.d. The Datatype Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
+ <table class="msgdesc">
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Datatype</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0003</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Variable</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Required for dataset or committed
+ datatype (formerly named datatype) objects; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td><p>The datatype message defines the datatype for each
+ element of a dataset or a common datatype for sharing between
+ multiple datasets. A datatype can describe an atomic type like a
+ fixed- or floating-point type or more complex types like a C struct
+ (compound datatype), array (array datatype) or C++ vector
+ (variable-length datatype).</p>
+ <p>Datatype messages that are part of a dataset object do not
+ describe how elements are related to one another; the dataspace
+ message is used for that purpose. Datatype messages that are part
+ of a committed datatype (formerly named datatype) message describe
+ a common datatype that can be shared by multiple datasets in the
+ file.</p></td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
+
+<div align="center">
+ <table class="format">
+ <caption>Datatype Message</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Class and Version</td>
+ <td>Class Bit Field, Bits 0-7</td>
+ <td>Class Bit Field, Bits 8-15</td>
+ <td>Class Bit Field, Bits 16-23</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />
+ <br />Properties<br />
+ <br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Class and Version</p></td>
+ <td>
+ <p>The version of the datatype message and the datatype&rsquo;s
+ class information are packed together in this field. The version
+ number is packed in the top 4 bits of the field and the class is
+ contained in the bottom 4 bits.</p>
+ <p>The version number information is used for changes in the
+ format of the datatype message and is described here:</p>
+ <table class="list">
<tr>
- <td align="center"><code>3</code></td>
- <td>Used when a VAX byte-ordered type needs to be
- encoded. Packs various other datatype classes more
- efficiently also.
- </td>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
</tr>
- </table></p>
- <p>The class of the datatype determines the format for the class
- bit field and properties portion of the datatype message, which
- are described below. The
- following classes are currently defined:
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Never used</td>
+ </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>Used by early versions of the library to encode compound
+ datatypes with explicit array fields. See the compound datatype
+ description below for further details.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>Used when an array datatype needs to be encoded.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>Used when a VAX byte-ordered type needs to be encoded.
+ Packs various other datatype classes more efficiently also.</td>
+ </tr>
+ </table>
+ <p></p>
+ <p>The class of the datatype determines the format for the class
+ bit field and properties portion of the datatype message, which are
+ described below. The following classes are currently defined:</p>
<table class="list">
<tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
</tr>
<tr>
- <td align="center"><code>0</code></td>
- <td>Fixed-Point</td>
+ <td align="center"><code>0</code></td>
+ <td>Fixed-Point</td>
</tr>
<tr>
- <td align="center"><code>1</code></td>
- <td>Floating-Point</td>
+ <td align="center"><code>1</code></td>
+ <td>Floating-Point</td>
</tr>
<tr>
- <td align="center"><code>2</code></td>
- <td>Time</td>
+ <td align="center"><code>2</code></td>
+ <td>Time</td>
</tr>
<tr>
- <td align="center"><code>3</code></td>
- <td>String</td>
+ <td align="center"><code>3</code></td>
+ <td>String</td>
</tr>
<tr>
- <td align="center"><code>4</code></td>
- <td>Bit field</td>
+ <td align="center"><code>4</code></td>
+ <td>Bit field</td>
</tr>
<tr>
- <td align="center"><code>5</code></td>
- <td>Opaque</td>
+ <td align="center"><code>5</code></td>
+ <td>Opaque</td>
</tr>
<tr>
- <td align="center"><code>6</code></td>
- <td>Compound</td>
+ <td align="center"><code>6</code></td>
+ <td>Compound</td>
</tr>
<tr>
- <td align="center"><code>7</code></td>
- <td>Reference</td>
+ <td align="center"><code>7</code></td>
+ <td>Reference</td>
</tr>
<tr>
- <td align="center"><code>8</code></td>
- <td>Enumerated</td>
+ <td align="center"><code>8</code></td>
+ <td>Enumerated</td>
</tr>
<tr>
- <td align="center"><code>9</code></td>
- <td>Variable-Length</td>
+ <td align="center"><code>9</code></td>
+ <td>Variable-Length</td>
</tr>
<tr>
- <td align="center"><code>10</code></td>
- <td>Array</td>
+ <td align="center"><code>10</code></td>
+ <td>Array</td>
</tr>
- </table></p>
+ </table>
+ <p></p>
- </td>
- </tr>
+ </td>
+ </tr>
- <tr>
- <td><p>Class Bit Fields</p></td>
- <td>
- <p>The information in these bit fields is specific to each datatype
- class and is described below. All bits not defined for a
- datatype class are set to zero.
- </p>
- </td>
- </tr>
+ <tr>
+ <td><p>Class Bit Fields</p></td>
+ <td>
+ <p>The information in these bit fields is specific to each
+ datatype class and is described below. All bits not defined for a
+ datatype class are set to zero.</p>
+ </td>
+ </tr>
- <tr>
- <td><p>Size</p></td>
- <td>
- <p>The size of a datatype element in bytes.
- </p>
- </td>
- </tr>
+ <tr>
+ <td><p>Size</p></td>
+ <td>
+ <p>The size of a datatype element in bytes.</p>
+ </td>
+ </tr>
- <tr>
- <td><p>Properties</p></td>
- <td>
- <p>This variable-sized sequence of bytes encodes information
- specific to each datatype class and is described for each class
- below. If there is no property information specified for a
- datatype class, the size of this field is zero bytes.
- </p>
- </td>
- </tr>
+ <tr>
+ <td><p>Properties</p></td>
+ <td>
+ <p>This variable-sized sequence of bytes encodes information
+ specific to each datatype class and is described for each class
+ below. If there is no property information specified for a datatype
+ class, the size of this field is zero bytes.</p>
+ </td>
+ </tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <p>Class specific information for Fixed-Point Numbers (Class 0):</p>
-
- <div align="center">
- <table class="desc">
- <caption>
- Fixed-point Bit Field Description
- </caption>
-
- <tr>
- <th width="10%">Bits</th>
- <th>Meaning</th>
- </tr>
-
- <tr>
- <td><p>0</p></td>
- <td><p><b>Byte Order.</b> If zero, byte order is little-endian;
- otherwise, byte order is big endian.</p></td>
- </tr>
-
- <tr>
- <td><p>1, 2</p></td>
- <td><p><b>Padding type.</b> Bit 1 is the lo_pad bit and bit 2
- is the hi_pad bit. If a datum has unused bits at either
- end, then the lo_pad or hi_pad bit is copied to those
- locations.</p></td>
- </tr>
-
- <tr>
- <td><p>3</p></td>
- <td><p><b>Signed.</b> If this bit is set then the fixed-point
- number is in 2&rsquo;s complement form.</p></td>
- </tr>
-
- <tr>
- <td><p>4-23</p></td>
- <td><p>Reserved (zero).</p></td>
- </tr>
- </table>
- </div>
+<br />
+<p>Class specific information for Fixed-Point Numbers (Class 0):</p>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Fixed-Point Property Description
- </caption>
-
- <tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- </tr>
-
- <tr>
- <td colspan="2">Bit Offset</td>
- <td colspan="2">Bit Precision</td>
- </tr>
- </table>
- </div>
+<div align="center">
+ <table class="desc">
+ <caption>Fixed-point Bit Field Description</caption>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Bit Offset</p></td>
- <td>
- <p>The bit offset of the first significant bit of the fixed-point
- value within the datatype. The bit offset specifies the number
- of bits &ldquo;to the right of&rdquo; the value (which are set to the
- lo_pad bit value).
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Bit Precision</p></td>
- <td>
- <p>The number of bits of precision of the fixed-point value
- within the datatype. This value, combined with the datatype
- element&rsquo;s size and the Bit Offset field specifies the number
- of bits &ldquo;to the left of&rdquo; the value (which are set to the
- hi_pad bit value).
- </p>
- </td>
- </tr>
+ <tr>
+ <th width="10%">Bits</th>
+ <th>Meaning</th>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td><p>0</p></td>
+ <td><p>
+ <b>Byte Order.</b> If zero, byte order is little-endian; otherwise,
+ byte order is big endian.
+ </p></td>
+ </tr>
+ <tr>
+ <td><p>1, 2</p></td>
+ <td><p>
+ <b>Padding type.</b> Bit 1 is the lo_pad bit and bit 2 is the
+ hi_pad bit. If a datum has unused bits at either end, then the
+ lo_pad or hi_pad bit is copied to those locations.
+ </p></td>
+ </tr>
- <br />
- <p>Class specific information for Floating-Point Numbers (Class 1):</p>
-
- <div align="center">
- <table class="desc">
- <caption>
- Floating-Point Bit Field Description
- </caption>
-
- <tr>
- <th width="10%">Bits</th>
- <th>Meaning</th>
- </tr>
-
- <tr>
- <td><p>0, 6</p></td>
- <td><p><b>Byte Order.</b> These two non-contiguous bits specify the
- &ldquo;endianness&rdquo; of the bytes in the datatype element.
- <table class="list">
- <tr>
- <th width="10%" align="center">Bit 6</th>
- <th width="10%" align="center">Bit 0</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td align="center"><code>0</code></td>
- <td>Byte order is little-endian
- </td>
- </tr>
- <tr>
- <td align="center"><code>0</code></td>
- <td align="center"><code>1</code></td>
- <td>Byte order is big-endian
- </td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td align="center"><code>0</code></td>
- <td>Reserved
- </td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td align="center"><code>1</code></td>
- <td>Byte order is VAX-endian
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>1, 2, 3</p></td>
- <td><p><b>Padding type.</b> Bit 1 is the low bits pad type, bit 2
- is the high bits pad type, and bit 3 is the internal bits
- pad type. If a datum has unused bits at either end or between
- the sign bit, exponent, or mantissa, then the value of bit
- 1, 2, or 3 is copied to those locations.</p></td>
- </tr>
-
- <tr>
- <td><p>4-5</p></td>
- <td><p><b>Mantissa Normalization.</b> This 2-bit bit field specifies
- how the most significant bit of the mantissa is managed.
+ <tr>
+ <td><p>3</p></td>
+ <td><p>
+ <b>Signed.</b> If this bit is set then the fixed-point number is in
+ 2&rsquo;s complement form.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>4-23</p></td>
+ <td><p>Reserved (zero).</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fixed-Point Property Description</caption>
+
+ <tr>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="2">Bit Offset</td>
+ <td colspan="2">Bit Precision</td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Bit Offset</p></td>
+ <td>
+ <p>The bit offset of the first significant bit of the
+ fixed-point value within the datatype. The bit offset specifies the
+ number of bits &ldquo;to the right of&rdquo; the value (which are
+ set to the lo_pad bit value).</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Bit Precision</p></td>
+ <td>
+ <p>The number of bits of precision of the fixed-point value
+ within the datatype. This value, combined with the datatype
+ element&rsquo;s size and the Bit Offset field specifies the number
+ of bits &ldquo;to the left of&rdquo; the value (which are set to
+ the hi_pad bit value).</p>
+ </td>
+ </tr>
+
+ </table>
+</div>
+
+
+<br />
+<p>Class specific information for Floating-Point Numbers (Class 1):</p>
+
+<div align="center">
+ <table class="desc">
+ <caption>Floating-Point Bit Field Description</caption>
+
+ <tr>
+ <th width="10%">Bits</th>
+ <th>Meaning</th>
+ </tr>
+
+ <tr>
+ <td><p>0, 6</p></td>
+ <td><p>
+ <b>Byte Order.</b> These two non-contiguous bits specify the
+ &ldquo;endianness&rdquo; of the bytes in the datatype element.
+ </p>
<table class="list">
<tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
+ <th width="10%" align="center">Bit 6</th>
+ <th width="10%" align="center">Bit 0</th>
+ <th width="80%" align="left">Description</th>
</tr>
<tr>
- <td align="center"><code>0</code></td>
- <td>No normalization
- </td>
+ <td align="center"><code>0</code></td>
+ <td align="center"><code>0</code></td>
+ <td>Byte order is little-endian</td>
</tr>
<tr>
- <td align="center"><code>1</code></td>
- <td>The most significant bit of the mantissa is always set
- (except for 0.0).
- </td>
+ <td align="center"><code>0</code></td>
+ <td align="center"><code>1</code></td>
+ <td>Byte order is big-endian</td>
</tr>
<tr>
- <td align="center"><code>2</code></td>
- <td>The most significant bit of the mantissa is not stored,
- but is implied to be set.
- </td>
+ <td align="center"><code>1</code></td>
+ <td align="center"><code>0</code></td>
+ <td>Reserved</td>
</tr>
<tr>
- <td align="center"><code>3</code></td>
- <td>Reserved.
- </td>
+ <td align="center"><code>1</code></td>
+ <td align="center"><code>1</code></td>
+ <td>Byte order is VAX-endian</td>
</tr>
- </table></p>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>1, 2, 3</p></td>
+ <td><p>
+ <b>Padding type.</b> Bit 1 is the low bits pad type, bit 2 is the
+ high bits pad type, and bit 3 is the internal bits pad type. If a
+ datum has unused bits at either end or between the sign bit,
+ exponent, or mantissa, then the value of bit 1, 2, or 3 is copied
+ to those locations.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>4-5</p></td>
+ <td><p>
+ <b>Mantissa Normalization.</b> This 2-bit bit field specifies how
+ the most significant bit of the mantissa is managed.
+ </p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>No normalization</td>
+ </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>The most significant bit of the mantissa is always set
+ (except for 0.0).</td>
+ </tr>
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>The most significant bit of the mantissa is not stored,
+ but is implied to be set.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>Reserved.</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>7</p></td>
+ <td><p>Reserved (zero).</p></td>
+ </tr>
+
+ <tr>
+ <td><p>8-15</p></td>
+ <td><p>
+ <b>Sign Location.</b> This is the bit position of the sign bit.
+ Bits are numbered with the least significant bit zero.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>16-23</p></td>
+ <td><p>Reserved (zero).</p></td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Floating-Point Property Description</caption>
+
+ <tr>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="2">Bit Offset</td>
+ <td colspan="2">Bit Precision</td>
+ </tr>
+
+ <tr>
+ <td>Exponent Location</td>
+ <td>Exponent Size</td>
+ <td>Mantissa Location</td>
+ <td>Mantissa Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Exponent Bias</td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Bit Offset</p></td>
+ <td>
+ <p>The bit offset of the first significant bit of the
+ floating-point value within the datatype. The bit offset specifies
+ the number of bits &ldquo;to the right of&rdquo; the value.</p>
</td>
- </tr>
+ </tr>
- <tr>
- <td><p>7</p></td>
- <td><p>Reserved (zero).</p></td>
- </tr>
+ <tr>
+ <td><p>Bit Precision</p></td>
+ <td>
+ <p>The number of bits of precision of the floating-point value
+ within the datatype.</p>
+ </td>
+ </tr>
- <tr>
- <td><p>8-15</p></td>
- <td><p><b>Sign Location.</b> This is the bit position of the sign
- bit. Bits are numbered with the least significant bit zero.</p></td>
- </tr>
+ <tr>
+ <td><p>Exponent Location</p></td>
+ <td>
+ <p>The bit position of the exponent field. Bits are numbered
+ with the least significant bit number zero.</p>
+ </td>
+ </tr>
- <tr>
- <td><p>16-23</p></td>
- <td><p>Reserved (zero).</p></td>
- </tr>
+ <tr>
+ <td><p>Exponent Size</p></td>
+ <td>
+ <p>The size of the exponent field in bits.</p>
+ </td>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td><p>Mantissa Location</p></td>
+ <td>
+ <p>The bit position of the mantissa field. Bits are numbered
+ with the least significant bit number zero.</p>
+ </td>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Floating-Point Property Description
- </caption>
-
- <tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- </tr>
-
- <tr>
- <td colspan="2">Bit Offset</td>
- <td colspan="2">Bit Precision</td>
- </tr>
-
- <tr>
- <td>Exponent Location</td>
- <td>Exponent Size</td>
- <td>Mantissa Location</td>
- <td>Mantissa Size</td>
- </tr>
-
- <tr>
- <td colspan="4">Exponent Bias</td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td><p>Mantissa Size</p></td>
+ <td>
+ <p>The size of the mantissa field in bits.</p>
+ </td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Bit Offset</p></td>
- <td>
- <p>The bit offset of the first significant bit of the floating-point
- value within the datatype. The bit offset specifies the number
- of bits &ldquo;to the right of&rdquo; the value.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Bit Precision</p></td>
- <td>
- <p>The number of bits of precision of the floating-point value
- within the datatype.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Exponent Location</p></td>
- <td>
- <p>The bit position of the exponent field. Bits are numbered with
- the least significant bit number zero.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Exponent Size</p></td>
- <td>
- <p>The size of the exponent field in bits.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Mantissa Location</p></td>
- <td>
- <p>The bit position of the mantissa field. Bits are numbered with
- the least significant bit number zero.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Mantissa Size</p></td>
- <td>
- <p>The size of the mantissa field in bits.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Exponent Bias</p></td>
- <td>
- <p>The bias of the exponent field.
- </p>
- </td>
- </tr>
+ <tr>
+ <td><p>Exponent Bias</p></td>
+ <td>
+ <p>The bias of the exponent field.</p>
+ </td>
+ </tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <p>Class specific information for Time (Class 2):</p>
-
-
- <div align="center">
- <table class="desc">
- <caption>
- Time Bit Field Description
- </caption>
-
- <tr>
- <th width="10%">Bits</th>
- <th>Meaning</th>
- </tr>
-
- <tr>
- <td><p>0</p></td>
- <td><p><b>Byte Order.</b> If zero, byte order is little-endian;
- otherwise, byte order is big endian.</p></td>
- </tr>
-
- <tr>
- <td><p>1-23</p></td>
- <td><p>Reserved (zero).</p></td>
- </tr>
- </table>
- </div>
+<br />
+<p>Class specific information for Time (Class 2):</p>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Time Property Description
- </caption>
-
- <tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- </tr>
-
- <tr>
- <td colspan="2">Bit Precision</td>
- </tr>
- </table>
- </div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Bit Precision</p></td>
- <td>
- <p>The number of bits of precision of the time value.
- </p>
- </td>
- </tr>
+<div align="center">
+ <table class="desc">
+ <caption>Time Bit Field Description</caption>
- </table>
- </div>
+ <tr>
+ <th width="10%">Bits</th>
+ <th>Meaning</th>
+ </tr>
+ <tr>
+ <td><p>0</p></td>
+ <td><p>
+ <b>Byte Order.</b> If zero, byte order is little-endian; otherwise,
+ byte order is big endian.
+ </p></td>
+ </tr>
- <br />
- <p>Class specific information for Strings (Class 3):</p>
-
-
- <div align="center">
- <table class="desc">
- <caption>
- String Bit Field Description
- </caption>
-
- <tr>
- <th width="10%">Bits</th>
- <th>Meaning</th>
- </tr>
-
- <tr>
- <td><p>0-3</p></td>
- <td><p><b>Padding type.</b> This four-bit value determines the
- type of padding to use for the string. The values are:
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Null Terminate: A zero byte marks the end of the
- string and is guaranteed to be present after
- converting a long string to a short string. When
- converting a short string to a long string the value is
- padded with additional null characters as necessary.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>Null Pad: Null characters are added to the end of
- the value during conversions from short values to long
- values but conversion in the opposite direction simply
- truncates the value.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>2</code></td>
- <td>Space Pad: Space characters are added to the end of
- the value during conversions from short values to long
- values but conversion in the opposite direction simply
- truncates the value. This is the Fortran
- representation of the string.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>3-15</code></td>
- <td>Reserved
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>4-7</p></td>
- <td><p><b>Character Set.</b> The character set used to
- encode the string.
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>ASCII character set encoding
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>UTF-8 character set encoding
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>2-15</code></td>
- <td>Reserved
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>8-23</p></td>
- <td><p>Reserved (zero).</p></td>
- </tr>
- </table>
- </div>
-
- <p>There are no properties defined for the string class.
- </p>
-
-
- <p>Class specific information for bit fields (Class 4):</p>
-
- <div align="center">
- <table class="desc">
- <caption>
- Bitfield Bit Field Description
- </caption>
-
- <tr>
- <th width="10%">Bits</th>
- <th>Meaning</th>
- </tr>
-
- <tr>
- <td><p>0</p></td>
- <td><p><b>Byte Order.</b> If zero, byte order is little-endian;
- otherwise, byte order is big endian.</p></td>
- </tr>
-
- <tr>
- <td><p>1, 2</p></td>
- <td><p><b>Padding type.</b> Bit 1 is the lo_pad type and bit 2
- is the hi_pad type. If a datum has unused bits at either
- end, then the lo_pad or hi_pad bit is copied to those
- locations.</p></td>
- </tr>
-
- <tr>
- <td><p>3-23</p></td>
- <td><p>Reserved (zero).</p></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td><p>1-23</p></td>
+ <td><p>Reserved (zero).</p></td>
+ </tr>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Bit Field Property Description
- </caption>
-
- <tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- </tr>
-
- <tr>
- <td colspan="2">Bit Offset</td>
- <td colspan="2">Bit Precision</td>
- </tr>
- </table>
- </div>
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Time Property Description</caption>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Bit Offset</p></td>
- <td>
- <p>The bit offset of the first significant bit of the bit field
- within the datatype. The bit offset specifies the number
- of bits &ldquo;to the right of&rdquo; the value.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Bit Precision</p></td>
- <td>
- <p>The number of bits of precision of the bit field
- within the datatype.
- </p>
- </td>
- </tr>
- </table>
- </div>
+ <tr>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ </tr>
+ <tr>
+ <td colspan="2">Bit Precision</td>
+ </tr>
+ </table>
+</div>
- <br />
- <p>Class specific information for Opaque (Class 5):</p>
-
- <div align="center">
- <table class="desc">
- <caption>
- Opaque Bit Field Description
- </caption>
-
- <tr>
- <th width="10%">Bits</th>
- <th>Meaning</th>
- </tr>
-
- <tr>
- <td><p>0-7</p></td>
- <td><p>Length of ASCII tag in bytes.</p></td>
- </tr>
-
- <tr>
- <td><p>8-23</p></td>
- <td><p>Reserved (zero).</p></td>
- </tr>
- </table>
- </div>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Opaque Property Description
- </caption>
-
- <tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- </tr>
-
- <tr>
- <td colspan="4"><br />ASCII Tag<br />
- <br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td><p>Bit Precision</p></td>
+ <td>
+ <p>The number of bits of precision of the time value.</p>
+ </td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>ASCII Tag</p></td>
- <td>
- <p>This NUL-terminated string provides a description for the
- opaque type. It is NUL-padded to a multiple of 8 bytes.
- </p>
- </td>
- </tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <p>Class specific information for Compound (Class 6):</p>
-
- <div align="center">
- <table class="desc">
- <caption>
- Compound Bit Field Description
- </caption>
-
- <tr>
- <th width="10%">Bits</th>
- <th>Meaning</th>
- </tr>
-
- <tr>
- <td><p>0-15</p></td>
- <td><p><b>Number of Members.</b> This field contains the number
- of members defined for the compound datatype. The member
- definitions are listed in the Properties field of the data
- type message.</p></td>
- </tr>
-
- <tr>
- <td><p>16-23</p></td>
- <td><p>Reserved (zero).</p></td>
- </tr>
- </table>
- </div>
+<br />
+<p>Class specific information for Strings (Class 3):</p>
- <p>The Properties field of a compound datatype is a list of the
- member definitions of the compound datatype. The member
- definitions appear one after another with no intervening bytes.
- The member types are described with a (recursively) encoded datatype
- message.</p>
+<div align="center">
+ <table class="desc">
+ <caption>String Bit Field Description</caption>
- <p>Note that the property descriptions are different for different
- versions of the datatype version. Additionally note that the version
- 0 datatype encoding is deprecated and has been replaced with later
- encodings in versions of the HDF5 Library from the 1.4 release
- onward.</p>
+ <tr>
+ <th width="10%">Bits</th>
+ <th>Meaning</th>
+ </tr>
+ <tr>
+ <td><p>0-3</p></td>
+ <td><p>
+ <b>Padding type.</b> This four-bit value determines the type of
+ padding to use for the string. The values are:
- <div align="center">
- <table class="format">
- <caption>
- Compound Properties Description for Datatype Version 1
- </caption>
+ </p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
- <tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- </tr>
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Null Terminate: A zero byte marks the end of the string
+ and is guaranteed to be present after converting a long string to
+ a short string. When converting a short string to a long string
+ the value is padded with additional null characters as necessary.
+ </td>
+ </tr>
- <tr>
- <td colspan="4"><br />Name<br /><br /></td>
- </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>Null Pad: Null characters are added to the end of the
+ value during conversions from short values to long values but
+ conversion in the opposite direction simply truncates the value.
+ </td>
+ </tr>
- <tr>
- <td colspan="4">Byte Offset of Member</td>
- </tr>
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>Space Pad: Space characters are added to the end of the
+ value during conversions from short values to long values but
+ conversion in the opposite direction simply truncates the value.
+ This is the Fortran representation of the string.</td>
+ </tr>
- <tr>
- <td>Dimensionality</td>
- <td colspan="3">Reserved (zero)</td>
- </tr>
+ <tr>
+ <td align="center"><code>3-15</code></td>
+ <td>Reserved</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
- <tr>
- <td colspan="4">Dimension Permutation</td>
- </tr>
+ <tr>
+ <td><p>4-7</p></td>
+ <td><p>
+ <b>Character Set.</b> The character set used to encode the string.
+ </p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
- <tr>
- <td colspan="4">Reserved (zero)</td>
- </tr>
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>ASCII character set encoding</td>
+ </tr>
- <tr>
- <td colspan="4">Dimension #1 Size (required)</td>
- </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>UTF-8 character set encoding</td>
+ </tr>
- <tr>
- <td colspan="4">Dimension #2 Size (required)</td>
- </tr>
+ <tr>
+ <td align="center"><code>2-15</code></td>
+ <td>Reserved</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
- <tr>
- <td colspan="4">Dimension #3 Size (required)</td>
- </tr>
+ <tr>
+ <td><p>8-23</p></td>
+ <td><p>Reserved (zero).</p></td>
+ </tr>
+ </table>
+</div>
- <tr>
- <td colspan="4">Dimension #4 Size (required)</td>
- </tr>
+<p>There are no properties defined for the string class.</p>
- <tr>
- <td colspan="4"><br />Member Type Message<br /><br /></td>
- </tr>
- </table>
- </div>
+<p>Class specific information for bit fields (Class 4):</p>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Name</p></td>
- <td>
- <p>This NUL-terminated string provides a description for the
- opaque type. It is NUL-padded to a multiple of 8 bytes.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Byte Offset of Member</p></td>
- <td>
- <p>This is the byte offset of the member within the datatype.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimensionality</p></td>
- <td>
- <p>If set to zero, this field indicates a scalar member. If set
- to a value greater than zero, this field indicates that the
- member is an array of values. For array members, the size of
- the array is indicated by the &lsquo;Size of Dimension n&rsquo; field in
- this message.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimension Permutation</p></td>
- <td>
- <p>This field was intended to allow an array field to have
- its dimensions permuted, but this was never implemented.
- This field should always be set to zero.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimension #n Size</p></td>
- <td>
- <p>This field is the size of a dimension of the array field as
- stored in the file. The first dimension stored in the list of
- dimensions is the slowest changing dimension and the last
- dimension stored is the fastest changing dimension.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Member Type Message</p></td>
- <td>
- <p>This field is a datatype message describing the datatype of
- the member.
- </p>
- </td>
- </tr>
+<div align="center">
+ <table class="desc">
+ <caption>Bitfield Bit Field Description</caption>
- </table>
- </div>
+ <tr>
+ <th width="10%">Bits</th>
+ <th>Meaning</th>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Compound Properties Description for Datatype Version 2
- </caption>
-
- <tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- </tr>
-
- <tr>
- <td colspan="4"><br />Name<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4">Byte Offset of Member</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Member Type Message<br /><br /></td>
- </tr>
+ <tr>
+ <td><p>0</p></td>
+ <td><p>
+ <b>Byte Order.</b> If zero, byte order is little-endian; otherwise,
+ byte order is big endian.
+ </p></td>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td><p>1, 2</p></td>
+ <td><p>
+ <b>Padding type.</b> Bit 1 is the lo_pad type and bit 2 is the
+ hi_pad type. If a datum has unused bits at either end, then the
+ lo_pad or hi_pad bit is copied to those locations.
+ </p></td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Name</p></td>
- <td>
- <p>This NUL-terminated string provides a description for the
- opaque type. It is NUL-padded to a multiple of 8 bytes.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Byte Offset of Member</p></td>
- <td>
- <p>This is the byte offset of the member within the datatype.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Member Type Message</p></td>
- <td>
- <p>This field is a datatype message describing the datatype of
- the member.
- </p>
- </td>
- </tr>
+ <tr>
+ <td><p>3-23</p></td>
+ <td><p>Reserved (zero).</p></td>
+ </tr>
+ </table>
+</div>
- </table>
- </div>
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Bit Field Property Description</caption>
+ <tr>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Compound Properties Description for Datatype Version 3
- </caption>
-
- <tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- </tr>
-
- <tr>
- <td colspan="4"><br />Name<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4">Byte Offset of Member <em>(variable size)</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Member Type Message<br /><br /></td>
- </tr>
+ <tr>
+ <td colspan="2">Bit Offset</td>
+ <td colspan="2">Bit Precision</td>
+ </tr>
+ </table>
+</div>
- </table>
- </div>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Name</p></td>
- <td><p>This NUL-terminated string provides a description for the
- opaque type. It is <em>not</em> NUL-padded to a multiple of 8
- bytes.</p></td>
- </tr>
-
- <tr>
- <td><p>Byte Offset of Member</p></td>
- <td><p>This is the byte offset of the member within the datatype.
- The field size is the minimum number of bytes necessary,
- based on the size of the datatype element. For example, a
- datatype element size of less than 256 bytes uses a 1 byte
- length, a datatype element size of 256-65535 bytes uses a
- 2 byte length, and so on.</p></td>
- </tr>
-
- <tr>
- <td><p>Member Type Message</p></td>
- <td><p>This field is a datatype message describing the datatype of
- the member.</p></td>
- </tr>
+ <tr>
+ <td><p>Bit Offset</p></td>
+ <td>
+ <p>The bit offset of the first significant bit of the bit field
+ within the datatype. The bit offset specifies the number of bits
+ &ldquo;to the right of&rdquo; the value.</p>
+ </td>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td><p>Bit Precision</p></td>
+ <td>
+ <p>The number of bits of precision of the bit field within the
+ datatype.</p>
+ </td>
+ </tr>
+ </table>
+</div>
- <br />
- <p>Class specific information for Reference (Class 7):</p>
-
- <div align="center">
- <table class="desc">
- <caption>
- Reference Bit Field Description
- </caption>
-
- <tr>
- <th width="10%">Bits</th>
- <th>Meaning</th>
- </tr>
-
- <tr>
- <td><p>0-3</p></td>
- <td><p><b>Type.</b> This four-bit value contains the type of reference
- described. The values defined are:
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Object Reference: A reference to another object in this
- HDF5 file.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>Dataset Region Reference: A reference to a region within
- a dataset in this HDF5 file.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>2-15</code></td>
- <td>Reserved
- </td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>4-23</p></td>
- <td><p>Reserved (zero).</p></td>
- </tr>
- </table>
- </div>
+<br />
+<p>Class specific information for Opaque (Class 5):</p>
- <p>There are no properties defined for the reference class.
- </p>
+<div align="center">
+ <table class="desc">
+ <caption>Opaque Bit Field Description</caption>
+ <tr>
+ <th width="10%">Bits</th>
+ <th>Meaning</th>
+ </tr>
- <br />
- <p>Class specific information for Enumeration (Class 8):</p>
-
- <div align="center">
- <table class="desc">
- <caption>
- Enumeration Bit Field Description
- </caption>
-
- <tr>
- <th width="10%">Bits</th>
- <th>Meaning</th>
- </tr>
-
- <tr>
- <td><p>0-15</p></td>
- <td><p><b>Number of Members.</b> The number of name/value
- pairs defined for the enumeration type.</p></td>
- </tr>
-
- <tr>
- <td><p>16-23</p></td>
- <td><p>Reserved (zero).</p></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td><p>0-7</p></td>
+ <td><p>Length of ASCII tag in bytes.</p></td>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Enumeration Property Description for Datatype Versions 1 & 2
- </caption>
+ <tr>
+ <td><p>8-23</p></td>
+ <td><p>Reserved (zero).</p></td>
+ </tr>
+ </table>
+</div>
- <tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- </tr>
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Opaque Property Description</caption>
- <tr>
- <td colspan="4"><br />Base Type<br /><br /></td>
- </tr>
+ <tr>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ </tr>
- <tr>
- <td colspan="4"><br />Names<br /><br /></td>
- </tr>
+ <tr>
+ <td colspan="4"><br />ASCII Tag<br /> <br /></td>
+ </tr>
+ </table>
+</div>
- <tr>
- <td colspan="4"><br />Values<br /><br /></td>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
- </table>
- </div>
+ <tr>
+ <td><p>ASCII Tag</p></td>
+ <td>
+ <p>This NUL-terminated string provides a description for the
+ opaque type. It is NUL-padded to a multiple of 8 bytes.</p>
+ </td>
+ </tr>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Base Type</p></td>
- <td>
- <p>Each enumeration type is based on some parent type, usually an
- integer. The information for that parent type is described
- recursively by this field.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Names</p></td>
- <td>
- <p>The name for each name/value pair. Each name is stored as a null
- terminated ASCII string in a multiple of eight bytes. The names
- are in no particular order.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Values</p></td>
- <td>
- <p>The list of values in the same order as the names. The values
- are packed (no inter-value padding) and the size of each value
- is determined by the parent type.
- </p>
- </td>
- </tr>
- </table>
- </div>
+<br />
+<p>Class specific information for Compound (Class 6):</p>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Enumeration Property Description for Datatype Version 3
- </caption>
+<div align="center">
+ <table class="desc">
+ <caption>Compound Bit Field Description</caption>
+
+ <tr>
+ <th width="10%">Bits</th>
+ <th>Meaning</th>
+ </tr>
+
+ <tr>
+ <td><p>0-15</p></td>
+ <td><p>
+ <b>Number of Members.</b> This field contains the number of members
+ defined for the compound datatype. The member definitions are
+ listed in the Properties field of the data type message.
+ </p></td>
+ </tr>
- <tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- </tr>
+ <tr>
+ <td><p>16-23</p></td>
+ <td><p>Reserved (zero).</p></td>
+ </tr>
+ </table>
+</div>
+
+
+<p>The Properties field of a compound datatype is a list of the
+ member definitions of the compound datatype. The member definitions
+ appear one after another with no intervening bytes. The member types
+ are described with a (recursively) encoded datatype message.</p>
- <tr>
- <td colspan="4"><br />Base Type<br /><br /></td>
- </tr>
+<p>Note that the property descriptions are different for different
+ versions of the datatype version. Additionally note that the version 0
+ datatype encoding is deprecated and has been replaced with later
+ encodings in versions of the HDF5 Library from the 1.4 release onward.</p>
- <tr>
- <td colspan="4"><br />Names<br /><br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Values<br /><br /></td>
+<div align="center">
+ <table class="format">
+ <caption>Compound Properties Description for Datatype
+ Version 1</caption>
+
+ <tr>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
</tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4"><br />Name<br />
+ <br /></td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Base Type</p></td>
- <td>
- <p>Each enumeration type is based on some parent type, usually an
- integer. The information for that parent type is described
- recursively by this field.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Names</p></td>
- <td>
- <p>The name for each name/value pair. Each name is stored as a null
- terminated ASCII string, <em>not</em> padded to a multiple of
- eight bytes. The names are in no particular order.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Values</p></td>
- <td>
- <p>The list of values in the same order as the names. The values
- are packed (no inter-value padding) and the size of each value
- is determined by the parent type.
- </p>
- </td>
- </tr>
+ <tr>
+ <td colspan="4">Byte Offset of Member</td>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td>Dimensionality</td>
+ <td colspan="3">Reserved (zero)</td>
+ </tr>
+ <tr>
+ <td colspan="4">Dimension Permutation</td>
+ </tr>
+ <tr>
+ <td colspan="4">Reserved (zero)</td>
+ </tr>
- <br />
- <p>Class specific information for Variable-Length (Class 9):</p>
-
- <div align="center">
- <table class="desc">
- <caption>
- Variable-Length Bit Field Description
- </caption>
-
- <tr>
- <th width="10%">Bits</th>
- <th>Meaning</th>
- </tr>
-
- <tr>
- <td><p>0-3</p></td>
- <td><p><b>Type.</b> This four-bit value contains the type of
- variable-length datatype described. The values defined are:
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Sequence: A variable-length sequence of any datatype.
- Variable-length sequences do not have padding or
- character set information.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>String: A variable-length sequence of characters.
- Variable-length strings have padding and character set
- information.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>2-15</code></td>
- <td>Reserved
- </td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>4-7</p></td>
- <td><p><b>Padding type.</b> (variable-length string only)
- This four-bit value determines the type of padding
- used for variable-length strings. The values are the same
- as for the string padding type, as follows:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Null terminate: A zero byte marks the end of a string
- and is guaranteed to be present after converting a long
- string to a short string. When converting a short string
- to a long string, the value is padded with additional null
- characters as necessary.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>Null pad: Null characters are added to the end of the
- value during conversion from a short string to a longer
- string. Conversion from a long string to a shorter string
- simply truncates the value.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>2</code></td>
- <td>Space pad: Space characters are added to the end of the
- value during conversion from a short string to a longer
- string. Conversion from a long string to a shorter string
- simply truncates the value. This is the Fortran
- representation of the string.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>3-15</code></td>
- <td>Reserved
- </td>
- </tr>
- </table></p>
-
- <p>This value is set to zero for variable-length sequences.</p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>8-11</p></td>
- <td><p><b>Character Set.</b> (variable-length string only)
- This four-bit value specifies the character set
- to be used for encoding the string:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>ASCII character set encoding
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>UTF-8 character set encoding
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>2-15</code></td>
- <td>Reserved
- </td>
- </tr>
- </table></p>
-
- <p>This value is set to zero for variable-length sequences.</p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>12-23</p></td>
- <td><p>Reserved (zero).</p></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4">Dimension #1 Size (required)</td>
+ </tr>
- <br />
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Variable-Length Property Description
- </caption>
+ <tr>
+ <td colspan="4">Dimension #2 Size (required)</td>
+ </tr>
<tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
+ <td colspan="4">Dimension #3 Size (required)</td>
</tr>
<tr>
- <td colspan="4"><br />Base Type<br /><br /></td>
+ <td colspan="4">Dimension #4 Size (required)</td>
</tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4"><br />Member Type Message<br />
+ <br /></td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="10%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Base Type</p></td>
- <td>
- <p>Each variable-length type is based on some parent type. The
- information for that parent type is described recursively by
- this field.
- </p>
- </td>
- </tr>
+ </table>
+</div>
- </table>
- </div>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Name</p></td>
+ <td>
+ <p>This NUL-terminated string provides a description for the
+ opaque type. It is NUL-padded to a multiple of 8 bytes.</p>
+ </td>
+ </tr>
+ <tr>
+ <td><p>Byte Offset of Member</p></td>
+ <td>
+ <p>This is the byte offset of the member within the datatype.</p>
+ </td>
+ </tr>
- <br />
- <p>Class specific information for Array (Class 10):</p>
+ <tr>
+ <td><p>Dimensionality</p></td>
+ <td>
+ <p>If set to zero, this field indicates a scalar member. If set
+ to a value greater than zero, this field indicates that the member
+ is an array of values. For array members, the size of the array is
+ indicated by the &lsquo;Size of Dimension n&rsquo; field in this
+ message.</p>
+ </td>
+ </tr>
- <p>There are no bit fields defined for the array class.
- </p>
+ <tr>
+ <td><p>Dimension Permutation</p></td>
+ <td>
+ <p>This field was intended to allow an array field to have its
+ dimensions permuted, but this was never implemented. This field
+ should always be set to zero.</p>
+ </td>
+ </tr>
- <p>Note that the dimension information defined in the property for this
- datatype class is independent of dataspace information for a dataset.
- The dimension information here describes the dimensionality of the
- information within a data element (or a component of an element, if the
- array datatype is nested within another datatype) and the dataspace for a
- dataset describes the size and locations of the elements in a dataset.
- </p>
+ <tr>
+ <td><p>Dimension #n Size</p></td>
+ <td>
+ <p>This field is the size of a dimension of the array field as
+ stored in the file. The first dimension stored in the list of
+ dimensions is the slowest changing dimension and the last dimension
+ stored is the fastest changing dimension.</p>
+ </td>
+ </tr>
+ <tr>
+ <td><p>Member Type Message</p></td>
+ <td>
+ <p>This field is a datatype message describing the datatype of
+ the member.</p>
+ </td>
+ </tr>
- <div align="center">
- <table class="format">
- <caption>
- Array Property Description for Datatype Version 2
- </caption>
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Compound Properties Description for Datatype
+ Version 2</caption>
<tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
</tr>
- <tr>
- <td>Dimensionality</td>
- <td colspan="3">Reserved (zero)</td>
- </tr>
+ <tr>
+ <td colspan="4"><br />Name<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Byte Offset of Member</td>
+ </tr>
- <tr>
- <td colspan="4">Dimension #1 Size</td>
- </tr>
- <tr>
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
- <tr>
- <td colspan="4">Dimension #n Size</td>
- </tr>
+ <tr>
+ <td colspan="4"><br />Member Type Message<br />
+ <br /></td>
+ </tr>
- <tr>
- <td colspan="4">Permutation Index #1</td>
- </tr>
- <tr>
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
- <tr>
- <td colspan="4">Permutation Index #n</td>
- </tr>
+ </table>
+</div>
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <td colspan="4"><br />Base Type<br /><br /></td>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
- </table>
- </div>
+ <tr>
+ <td><p>Name</p></td>
+ <td>
+ <p>This NUL-terminated string provides a description for the
+ opaque type. It is NUL-padded to a multiple of 8 bytes.</p>
+ </td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Dimensionality</p></td>
- <td>
- <p>This value is the number of dimensions that the array has.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimension #n Size</p></td>
- <td>
- <p>This value is the size of the dimension of the array
- as stored in the file. The first dimension stored in
- the list of dimensions is the slowest changing dimension
- and the last dimension stored is the fastest changing
- dimension.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Permutation Index #n</p></td>
- <td>
- <p>This value is the index permutation used to map
- each dimension from the canonical representation to an
- alternate axis for each dimension. Currently, dimension
- permutations are not supported, and these indices should
- be set to the index position minus one. In other words,
- the first dimension should be set to 0, the second dimension
- should be set to 1, and so on.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Base Type</p></td>
- <td>
- <p>Each array type is based on some parent type. The
- information for that parent type is described recursively by
- this field.
- </p>
- </td>
- </tr>
+ <tr>
+ <td><p>Byte Offset of Member</p></td>
+ <td>
+ <p>This is the byte offset of the member within the datatype.</p>
+ </td>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td><p>Member Type Message</p></td>
+ <td>
+ <p>This field is a datatype message describing the datatype of
+ the member.</p>
+ </td>
+ </tr>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Array Property Description for Datatype Version 3
- </caption>
+ </table>
+</div>
+
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Compound Properties Description for Datatype
+ Version 3</caption>
<tr>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
- <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
</tr>
- <tr>
- <td>Dimensionality</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <tr>
+ <td colspan="4"><br />Name<br />
+ <br /></td>
+ </tr>
- <tr>
- <td colspan="4">Dimension #1 Size</td>
- </tr>
- <tr>
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
- <tr>
- <td colspan="4">Dimension #n Size</td>
- </tr>
+ <tr>
+ <td colspan="4">Byte Offset of Member <em>(variable size)</em></td>
+ </tr>
<tr>
- <td colspan="4"><br />Base Type<br /><br /></td>
+ <td colspan="4"><br />Member Type Message<br />
+ <br /></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Dimensionality</p></td>
- <td>
- <p>This value is the number of dimensions that the array has.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimension #n Size</p></td>
- <td>
- <p>This value is the size of the dimension of the array
- as stored in the file. The first dimension stored in
- the list of dimensions is the slowest changing dimension
- and the last dimension stored is the fastest changing
- dimension.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Base Type</p></td>
- <td>
- <p>Each array type is based on some parent type. The
- information for that parent type is described recursively by
- this field.
- </p>
- </td>
- </tr>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td><p>Name</p></td>
+ <td><p>
+ This NUL-terminated string provides a description for the opaque
+ type. It is <em>not</em> NUL-padded to a multiple of 8 bytes.
+ </p></td>
+ </tr>
+ <tr>
+ <td><p>Byte Offset of Member</p></td>
+ <td><p>This is the byte offset of the member within the
+ datatype. The field size is the minimum number of bytes necessary,
+ based on the size of the datatype element. For example, a datatype
+ element size of less than 256 bytes uses a 1 byte length, a
+ datatype element size of 256-65535 bytes uses a 2 byte length, and
+ so on.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Member Type Message</p></td>
+ <td><p>This field is a datatype message describing the
+ datatype of the member.</p></td>
+ </tr>
+
+ </table>
+</div>
<br />
-<h4><a name="OldFillValueMessage">IV.A.2.e. The Data Storage -
-Fill Value (Old) Message</a></h4>
+<p>Class specific information for Reference (Class 7):</p>
- <!-- start msgdesc table -->
- <center>
+<div align="center">
+ <table class="desc">
+ <caption>Reference Bit Field Description</caption>
+
+ <tr>
+ <th width="10%">Bits</th>
+ <th>Meaning</th>
+ </tr>
+
+ <tr>
+ <td><p>0-3</p></td>
+ <td><p>
+ <b>Type.</b> This four-bit value contains the type of reference
+ described. The values defined are:
+
+ </p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Object Reference: A reference to another object in this
+ HDF5 file.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>Dataset Region Reference: A reference to a region within
+ a dataset in this HDF5 file.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2-15</code></td>
+ <td>Reserved</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>4-23</p></td>
+ <td><p>Reserved (zero).</p></td>
+ </tr>
+ </table>
+</div>
+
+<p>There are no properties defined for the reference class.</p>
+
+
+<br />
+<p>Class specific information for Enumeration (Class 8):</p>
+
+<div align="center">
+ <table class="desc">
+ <caption>Enumeration Bit Field Description</caption>
+
+ <tr>
+ <th width="10%">Bits</th>
+ <th>Meaning</th>
+ </tr>
+
+ <tr>
+ <td><p>0-15</p></td>
+ <td><p>
+ <b>Number of Members.</b> The number of name/value pairs defined
+ for the enumeration type.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>16-23</p></td>
+ <td><p>Reserved (zero).</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Enumeration Property Description for Datatype
+ Versions 1 & 2</caption>
+
+ <tr>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Base Type<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Names<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Values<br />
+ <br /></td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Base Type</p></td>
+ <td>
+ <p>Each enumeration type is based on some parent type, usually
+ an integer. The information for that parent type is described
+ recursively by this field.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Names</p></td>
+ <td>
+ <p>The name for each name/value pair. Each name is stored as a
+ null terminated ASCII string in a multiple of eight bytes. The
+ names are in no particular order.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Values</p></td>
+ <td>
+ <p>The list of values in the same order as the names. The values
+ are packed (no inter-value padding) and the size of each value is
+ determined by the parent type.</p>
+ </td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Enumeration Property Description for Datatype
+ Version 3</caption>
+
+ <tr>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Base Type<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Names<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Values<br />
+ <br /></td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Base Type</p></td>
+ <td>
+ <p>Each enumeration type is based on some parent type, usually
+ an integer. The information for that parent type is described
+ recursively by this field.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Names</p></td>
+ <td>
+ <p>
+ The name for each name/value pair. Each name is stored as a null
+ terminated ASCII string, <em>not</em> padded to a multiple of eight
+ bytes. The names are in no particular order.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Values</p></td>
+ <td>
+ <p>The list of values in the same order as the names. The values
+ are packed (no inter-value padding) and the size of each value is
+ determined by the parent type.</p>
+ </td>
+ </tr>
+
+ </table>
+</div>
+
+
+
+<br />
+<p>Class specific information for Variable-Length (Class 9):</p>
+
+<div align="center">
+ <table class="desc">
+ <caption>Variable-Length Bit Field Description</caption>
+
+ <tr>
+ <th width="10%">Bits</th>
+ <th>Meaning</th>
+ </tr>
+
+ <tr>
+ <td><p>0-3</p></td>
+ <td><p>
+ <b>Type.</b> This four-bit value contains the type of
+ variable-length datatype described. The values defined are:
+
+ </p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Sequence: A variable-length sequence of any datatype.
+ Variable-length sequences do not have padding or character set
+ information.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>String: A variable-length sequence of characters.
+ Variable-length strings have padding and character set
+ information.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2-15</code></td>
+ <td>Reserved</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>4-7</p></td>
+ <td><p>
+ <b>Padding type.</b> (variable-length string only) This four-bit
+ value determines the type of padding used for variable-length
+ strings. The values are the same as for the string padding type, as
+ follows:
+ </p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Null terminate: A zero byte marks the end of a string and
+ is guaranteed to be present after converting a long string to a
+ short string. When converting a short string to a long string,
+ the value is padded with additional null characters as necessary.
+ </td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>Null pad: Null characters are added to the end of the
+ value during conversion from a short string to a longer string.
+ Conversion from a long string to a shorter string simply
+ truncates the value.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>Space pad: Space characters are added to the end of the
+ value during conversion from a short string to a longer string.
+ Conversion from a long string to a shorter string simply
+ truncates the value. This is the Fortran representation of the
+ string.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>3-15</code></td>
+ <td>Reserved</td>
+ </tr>
+ </table>
+ <p></p>
+
+ <p>This value is set to zero for variable-length sequences.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>8-11</p></td>
+ <td><p>
+ <b>Character Set.</b> (variable-length string only) This four-bit
+ value specifies the character set to be used for encoding the
+ string:
+ </p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>ASCII character set encoding</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>UTF-8 character set encoding</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2-15</code></td>
+ <td>Reserved</td>
+ </tr>
+ </table>
+ <p></p>
+
+ <p>This value is set to zero for variable-length sequences.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>12-23</p></td>
+ <td><p>Reserved (zero).</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Variable-Length Property Description</caption>
+
+ <tr>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Base Type<br />
+ <br /></td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="10%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Base Type</p></td>
+ <td>
+ <p>Each variable-length type is based on some parent type. The
+ information for that parent type is described recursively by this
+ field.</p>
+ </td>
+ </tr>
+
+ </table>
+</div>
+
+
+<br />
+<p>Class specific information for Array (Class 10):</p>
+
+<p>There are no bit fields defined for the array class.</p>
+
+<p>Note that the dimension information defined in the property for
+ this datatype class is independent of dataspace information for a
+ dataset. The dimension information here describes the dimensionality of
+ the information within a data element (or a component of an element, if
+ the array datatype is nested within another datatype) and the dataspace
+ for a dataset describes the size and locations of the elements in a
+ dataset.</p>
+
+
+<div align="center">
+ <table class="format">
+ <caption>Array Property Description for Datatype Version 2</caption>
+
+ <tr>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ </tr>
+
+ <tr>
+ <td>Dimensionality</td>
+ <td colspan="3">Reserved (zero)</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Dimension #1 Size</td>
+ </tr>
+ <tr>
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
+ <tr>
+ <td colspan="4">Dimension #n Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Permutation Index #1</td>
+ </tr>
+ <tr>
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
+ <tr>
+ <td colspan="4">Permutation Index #n</td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Base Type<br />
+ <br /></td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Dimensionality</p></td>
+ <td>
+ <p>This value is the number of dimensions that the array has.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Dimension #n Size</p></td>
+ <td>
+ <p>This value is the size of the dimension of the array as
+ stored in the file. The first dimension stored in the list of
+ dimensions is the slowest changing dimension and the last dimension
+ stored is the fastest changing dimension.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Permutation Index #n</p></td>
+ <td>
+ <p>This value is the index permutation used to map each
+ dimension from the canonical representation to an alternate axis
+ for each dimension. Currently, dimension permutations are not
+ supported, and these indices should be set to the index position
+ minus one. In other words, the first dimension should be set to 0,
+ the second dimension should be set to 1, and so on.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Base Type</p></td>
+ <td>
+ <p>Each array type is based on some parent type. The information
+ for that parent type is described recursively by this field.</p>
+ </td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Array Property Description for Datatype Version 3</caption>
+
+ <tr>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ <th width="25%">Byte</th>
+ </tr>
+
+ <tr>
+ <td>Dimensionality</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Dimension #1 Size</td>
+ </tr>
+ <tr>
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
+ <tr>
+ <td colspan="4">Dimension #n Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Base Type<br />
+ <br /></td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Dimensionality</p></td>
+ <td>
+ <p>This value is the number of dimensions that the array has.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Dimension #n Size</p></td>
+ <td>
+ <p>This value is the size of the dimension of the array as
+ stored in the file. The first dimension stored in the list of
+ dimensions is the slowest changing dimension and the last dimension
+ stored is the fastest changing dimension.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Base Type</p></td>
+ <td>
+ <p>Each array type is based on some parent type. The information
+ for that parent type is described recursively by this field.</p>
+ </td>
+ </tr>
+
+ </table>
+</div>
+
+
+
+<br />
+<h4>
+ <a name="OldFillValueMessage">IV.A.2.e. The Data Storage - Fill
+ Value (Old) Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Fill Value
- (old)</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0004</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td><p>The fill value message stores a single data value which
- is returned to the application when an uninitialized data element
- is read from a dataset. The fill value is interpreted with the
- same datatype as the dataset. If no fill value message is present
- then a fill value of all zero bytes is assumed.</p>
- <p>This fill value message is deprecated in favor of the
- &ldquo;new&rdquo; fill value message (Message Type 0x0005) and
- is only written to the file for forward compatibility with
- versions of the HDF5 Library before the 1.6.0 version.
- Additionally, it only appears for datasets with a user-defined
- fill value (as opposed to the library default fill value or an
- explicitly set &ldquo;undefined&rdquo; fill value).</p>
- </td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Fill Value Message (Old)
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td colspan="4">Size</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Fill Value <em>(optional, variable size)</em><br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Fill Value (old)</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0004</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td><p>The fill value message stores a single data value
+ which is returned to the application when an uninitialized data
+ element is read from a dataset. The fill value is interpreted with
+ the same datatype as the dataset. If no fill value message is
+ present then a fill value of all zero bytes is assumed.</p>
+ <p>This fill value message is deprecated in favor of the
+ &ldquo;new&rdquo; fill value message (Message Type 0x0005) and is
+ only written to the file for forward compatibility with versions of
+ the HDF5 Library before the 1.6.0 version. Additionally, it only
+ appears for datasets with a user-defined fill value (as opposed to
+ the library default fill value or an explicitly set
+ &ldquo;undefined&rdquo; fill value).</p></td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Size</p></td>
- <td>
- <p>This is the size of the Fill Value field in bytes.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Fill Value</p></td>
- <td>
- <p>The fill value. The bytes of the fill value are interpreted
- using the same datatype as for the dataset.
- </p>
- </td>
- </tr>
- </table>
- </div>
+<div align="center">
+ <table class="format">
+ <caption>Fill Value Message (Old)</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+ <tr>
+ <td colspan="4">Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Fill Value <em>(optional, variable
+ size)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="FillValueMessage">IV.A.2.f. The Data Storage -
-Fill Value Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Size</p></td>
+ <td>
+ <p>This is the size of the Fill Value field in bytes.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Fill Value</p></td>
+ <td>
+ <p>The fill value. The bytes of the fill value are interpreted
+ using the same datatype as for the dataset.</p>
+ </td>
+ </tr>
+ </table>
+</div>
+
+
+<br />
+<h4>
+ <a name="FillValueMessage">IV.A.2.f. The Data Storage - Fill Value
+ Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Fill
- Value</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0005</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies</td></tr>
- <tr><td colspan="2"><b>Status:</b> Required for dataset objects;
- may not be repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>The fill value message stores a single data value which is
- returned to the application when an uninitialized data element
- is read from a dataset. The fill value is interpreted with the
- same datatype as the dataset.</td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Fill Value Message - Versions 1 & 2
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Space Allocation Time</td>
- <td>Fill Value Write Time</td>
- <td>Fill Value Defined</td>
- </tr>
-
- <tr>
- <td colspan="4">Size <em>(optional)</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Fill Value <em>(optional, variable size)</em><br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Fill Value</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0005</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Required for dataset objects; may
+ not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>The fill value message stores a single data value which is
+ returned to the application when an uninitialized data element is
+ read from a dataset. The fill value is interpreted with the same
+ datatype as the dataset.</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td>
- <p>The version number information is used for changes in the
- format of the fill value message and is described here:
+<div align="center">
+ <table class="format">
+ <caption>Fill Value Message - Versions 1 & 2</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td>Space Allocation Time</td>
+ <td>Fill Value Write Time</td>
+ <td>Fill Value Defined</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Size <em>(optional)</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Fill Value <em>(optional, variable
+ size)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>The version number information is used for changes in the
+ format of the fill value message and is described here:</p>
<table class="list">
<tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
</tr>
<tr>
- <td align="center"><code>0</code></td>
- <td>Never used
- </td>
+ <td align="center"><code>0</code></td>
+ <td>Never used</td>
</tr>
<tr>
- <td align="center"><code>1</code></td>
- <td>Initial version of this message.
- </td>
+ <td align="center"><code>1</code></td>
+ <td>Initial version of this message.</td>
</tr>
<tr>
- <td align="center"><code>2</code></td>
- <td>In this version, the Size and Fill Value fields are
- only present if the Fill Value Defined field is set
- to 1.
- </td>
+ <td align="center"><code>2</code></td>
+ <td>In this version, the Size and Fill Value fields are only
+ present if the Fill Value Defined field is set to 1.</td>
</tr>
<tr>
- <td align="center"><code>3</code></td>
- <td>This version packs the other fields in the message
- more efficiently than version 2.
- </td>
+ <td align="center"><code>3</code></td>
+ <td>This version packs the other fields in the message more
+ efficiently than version 2.</td>
</tr>
- </table></p>
- </p>
- </td>
- </tr>
+ </table>
+ <p></p>
+ <p></p>
+ </td>
+ </tr>
- <tr>
- <td><p>Space Allocation Time</p></td>
- <td>
- <p>When the storage space for the dataset&rsquo;s raw data will be
- allocated. The allowed values are:
+ <tr>
+ <td><p>Space Allocation Time</p></td>
+ <td>
+ <p>When the storage space for the dataset&rsquo;s raw data will
+ be allocated. The allowed values are:</p>
<table class="list">
<tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
</tr>
<tr>
- <td align="center"><code>0</code></td>
- <td>Not used.
- </td>
+ <td align="center"><code>0</code></td>
+ <td>Not used.</td>
</tr>
<tr>
- <td align="center"><code>1</code></td>
- <td>Early allocation. Storage space for the entire dataset
- should be allocated in the file when the dataset is
- created.
- </td>
+ <td align="center"><code>1</code></td>
+ <td>Early allocation. Storage space for the entire dataset
+ should be allocated in the file when the dataset is created.</td>
</tr>
<tr>
- <td align="center"><code>2</code></td>
- <td>Late allocation. Storage space for the entire dataset
- should not be allocated until the dataset is written
- to.
- </td>
+ <td align="center"><code>2</code></td>
+ <td>Late allocation. Storage space for the entire dataset
+ should not be allocated until the dataset is written to.</td>
</tr>
<tr>
- <td align="center"><code>3</code></td>
- <td>Incremental allocation. Storage space for the
- dataset should not be allocated until the portion
- of the dataset is written to. This is currently
- used in conjunction with chunked data storage for
- datasets.
- </td>
+ <td align="center"><code>3</code></td>
+ <td>Incremental allocation. Storage space for the dataset
+ should not be allocated until the portion of the dataset is
+ written to. This is currently used in conjunction with chunked
+ data storage for datasets.</td>
</tr>
- </table></p>
+ </table>
+ <p></p>
- </td>
- </tr>
+ </td>
+ </tr>
- <tr>
- <td><p>Fill Value Write Time</p></td>
- <td>
- <p>At the time that storage space for the dataset&rsquo;s raw data is
- allocated, this value indicates whether the fill value should
- be written to the raw data storage elements. The allowed values
- are:
+ <tr>
+ <td><p>Fill Value Write Time</p></td>
+ <td>
+ <p>At the time that storage space for the dataset&rsquo;s raw
+ data is allocated, this value indicates whether the fill value
+ should be written to the raw data storage elements. The allowed
+ values are:</p>
<table class="list">
<tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>On allocation. The fill value is always written to
- the raw data storage when the storage space is allocated.
- </td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td>Never. The fill value should never be written to
- the raw data storage.
- </td>
- </tr>
- <tr>
- <td align="center"><code>2</code></td>
- <td>Fill value written if set by user. The fill value
- will be written to the raw data storage when the storage
- space is allocated only if the user explicitly set
- the fill value. If the fill value is the library
- default or is undefined, it will not be written to
- the raw data storage.
- </td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>Fill Value Defined</p></td>
- <td>
- <p>This value indicates if a fill value is defined for this
- dataset. If this value is 0, the fill value is undefined.
- If this value is 1, a fill value is defined for this dataset.
- For version 2 or later of the fill value message, this value
- controls the presence of the Size and Fill Value fields.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Size</p></td>
- <td>
- <p>This is the size of the Fill Value field in bytes. This field
- is not present if the Version field is greater than 1,
- and the Fill Value Defined field is set to 0.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Fill Value</p></td>
- <td>
- <p>The fill value. The bytes of the fill value are interpreted
- using the same datatype as for the dataset. This field is
- not present if the Version field is greater than 1,
- and the Fill Value Defined field is set to 0.
- </p>
- </td>
- </tr>
- </table>
- </div>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Fill Value Message - Version 3
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Flags</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4">Size <em>(optional)</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Fill Value <em>(optional, variable size)</em><br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>On allocation. The fill value is always written to the
+ raw data storage when the storage space is allocated.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>Never. The fill value should never be written to the raw
+ data storage.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>Fill value written if set by user. The fill value will be
+ written to the raw data storage when the storage space is
+ allocated only if the user explicitly set the fill value. If the
+ fill value is the library default or is undefined, it will not be
+ written to the raw data storage.</td>
+ </tr>
+ </table>
+ <p></p>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td>
- <p>The version number information is used for changes in the
- format of the fill value message and is described here:
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Fill Value Defined</p></td>
+ <td>
+ <p>This value indicates if a fill value is defined for this
+ dataset. If this value is 0, the fill value is undefined. If this
+ value is 1, a fill value is defined for this dataset. For version 2
+ or later of the fill value message, this value controls the
+ presence of the Size and Fill Value fields.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Size</p></td>
+ <td>
+ <p>This is the size of the Fill Value field in bytes. This field
+ is not present if the Version field is greater than 1, and the Fill
+ Value Defined field is set to 0.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Fill Value</p></td>
+ <td>
+ <p>The fill value. The bytes of the fill value are interpreted
+ using the same datatype as for the dataset. This field is not
+ present if the Version field is greater than 1, and the Fill Value
+ Defined field is set to 0.</p>
+ </td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Fill Value Message - Version 3</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td>Flags</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Size <em>(optional)</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Fill Value <em>(optional, variable
+ size)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>The version number information is used for changes in the
+ format of the fill value message and is described here:</p>
<table class="list">
<tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
</tr>
<tr>
- <td align="center"><code>0</code></td>
- <td>Never used
- </td>
+ <td align="center"><code>0</code></td>
+ <td>Never used</td>
</tr>
<tr>
- <td align="center"><code>1</code></td>
- <td>Initial version of this message.
- </td>
+ <td align="center"><code>1</code></td>
+ <td>Initial version of this message.</td>
</tr>
<tr>
- <td align="center"><code>2</code></td>
- <td>In this version, the Size and Fill Value fields are
- only present if the Fill Value Defined field is set
- to 1.
- </td>
+ <td align="center"><code>2</code></td>
+ <td>In this version, the Size and Fill Value fields are only
+ present if the Fill Value Defined field is set to 1.</td>
</tr>
<tr>
- <td align="center"><code>3</code></td>
- <td>This version packs the other fields in the message
- more efficiently than version 2.
- </td>
+ <td align="center"><code>3</code></td>
+ <td>This version packs the other fields in the message more
+ efficiently than version 2.</td>
</tr>
- </table></p>
+ </table>
+ <p></p>
- </td>
- </tr>
+ </td>
+ </tr>
- <tr>
- <td><p>Flags</p></td>
- <td>
- <p>When the storage space for the dataset&rsquo;s raw data will be
- allocated. The allowed values are:
+ <tr>
+ <td><p>Flags</p></td>
+ <td>
+ <p>When the storage space for the dataset&rsquo;s raw data will
+ be allocated. The allowed values are:</p>
<table class="list">
<tr>
- <th width="20%" align="center">Bits</th>
- <th width="80%" align="left">Description</th>
+ <th width="20%" align="center">Bits</th>
+ <th width="80%" align="left">Description</th>
</tr>
<tr>
- <td align="center"><code>0-1</code></td>
- <td>Space Allocation Time, with the same
- values as versions 1 and 2 of the message.
- </td>
+ <td align="center"><code>0-1</code></td>
+ <td>Space Allocation Time, with the same values as versions 1
+ and 2 of the message.</td>
</tr>
<tr>
- <td align="center"><code>2-3</code></td>
- <td>Fill Value Write Time, with the same
- values as versions 1 and 2 of the message.
- </td>
+ <td align="center"><code>2-3</code></td>
+ <td>Fill Value Write Time, with the same values as versions 1
+ and 2 of the message.</td>
</tr>
<tr>
- <td align="center"><code>4</code></td>
- <td>Fill Value Undefined, indicating that the fill
- value has been marked as &ldquo;undefined&rdquo; for this dataset.
- Bits 4 and 5 cannot both be set.
- </td>
+ <td align="center"><code>4</code></td>
+ <td>Fill Value Undefined, indicating that the fill value has
+ been marked as &ldquo;undefined&rdquo; for this dataset. Bits 4
+ and 5 cannot both be set.</td>
</tr>
<tr>
- <td align="center"><code>5</code></td>
- <td>Fill Value Defined, with the same values as
- versions 1 and 2 of the message.
- Bits 4 and 5 cannot both be set.
- </td>
+ <td align="center"><code>5</code></td>
+ <td>Fill Value Defined, with the same values as versions 1
+ and 2 of the message. Bits 4 and 5 cannot both be set.</td>
</tr>
<tr>
- <td align="center"><code>6-7</code></td>
- <td>Reserved (zero).
- </td>
+ <td align="center"><code>6-7</code></td>
+ <td>Reserved (zero).</td>
</tr>
- </table></p>
+ </table>
+ <p></p>
- </td>
- </tr>
+ </td>
+ </tr>
- <tr>
- <td><p>Size</p></td>
- <td>
- <p>This is the size of the Fill Value field in bytes. This field
- is not present if the Version field is greater than 1,
- and the Fill Value Defined flag is set to 0.
- </p>
- </td>
- </tr>
+ <tr>
+ <td><p>Size</p></td>
+ <td>
+ <p>This is the size of the Fill Value field in bytes. This field
+ is not present if the Version field is greater than 1, and the Fill
+ Value Defined flag is set to 0.</p>
+ </td>
+ </tr>
- <tr>
- <td><p>Fill Value</p></td>
- <td>
- <p>The fill value. The bytes of the fill value are interpreted
- using the same datatype as for the dataset. This field is
- not present if the Version field is greater than 1,
- and the Fill Value Defined flag is set to 0.
- </p>
- </td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td><p>Fill Value</p></td>
+ <td>
+ <p>The fill value. The bytes of the fill value are interpreted
+ using the same datatype as for the dataset. This field is not
+ present if the Version field is greater than 1, and the Fill Value
+ Defined flag is set to 0.</p>
+ </td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="LinkMessage">IV.A.2.g. The Link Message</a></h4>
+<h4>
+ <a name="LinkMessage">IV.A.2.g. The Link Message</a>
+</h4>
- <!-- start msgdesc table -->
- <center>
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Link</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0006</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies </td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may be
- repeated. </td></tr>
- <tr><td><b>Description:</b></td>
- <td><p>This message encodes the information for a link in a
- group&rsquo;s object header, when the group is storing its links
- &ldquo;compactly&rdquo;, or in the group&rsquo;s fractal heap,
- when the group is storing its links &ldquo;densely&rdquo;.</p>
- <p>A group is storing its links compactly when the fractal heap
- address in the <em><a href="#LinkInfoMessage">Link Info
- Message</a></em> is set to the &ldquo;undefined address&rdquo;
- value.</p></td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Link Message
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Flags</td>
- <td>Link type <em>(optional)</em></td>
- <td bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
- <tr>
- <td colspan="4"><br />Creation Order <em>(8 bytes, optional)</em><br /><br /></td>
- </tr>
- <tr>
- <td>Link Name Character Set <em>(optional)</em></td>
- <td>Length of Link Name (variable size)</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
- <tr>
- <td colspan="4">Link Name (variable size)</td>
- </tr>
- <tr>
- <td colspan="4"><br />Link Information (variable size)<br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Link</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0006</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td><p>This message encodes the information for a link in a
+ group&rsquo;s object header, when the group is storing its links
+ &ldquo;compactly&rdquo;, or in the group&rsquo;s fractal heap, when
+ the group is storing its links &ldquo;densely&rdquo;.</p>
+ <p>
+ A group is storing its links compactly when the fractal heap
+ address in the <em><a href="#LinkInfoMessage">Link Info
+ Message</a></em> is set to the &ldquo;undefined address&rdquo; value.
+ </p></td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number for this message. This document describes version 1.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Flags</p></td>
- <td><p>This field contains information about the link and controls
- the presence of other fields below.
+<div align="center">
+ <table class="format">
+ <caption>Link Message</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td>Flags</td>
+ <td>Link type <em>(optional)</em></td>
+ <td bgcolor="#DDDDDD"><em>This space inserted only to align
+ table nicely</em></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Creation Order <em>(8 bytes,
+ optional)</em><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td>Link Name Character Set <em>(optional)</em></td>
+ <td>Length of Link Name (variable size)</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+ <tr>
+ <td colspan="4">Link Name (variable size)</td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Link Information (variable size)<br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number for this message. This document
+ describes version 1.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Flags</p></td>
+ <td><p>This field contains information about the link and
+ controls the presence of other fields below.</p>
<table class="list">
<tr>
- <th width="20%" align="center">Bits</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0-1</code></td>
- <td>Determines the size of the <em>Length of Link Name</em>
- field.
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>The size of the <em>Length of Link Name</em>
- field is 1 byte.
- </td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td>The size of the <em>Length of Link Name</em>
- field is 2 bytes.
- </td>
- </tr>
- <tr>
- <td align="center"><code>2</code></td>
- <td>The size of the <em>Length of Link Name</em>
- field is 4 bytes.
- </td>
- </tr>
- <tr>
- <td align="center"><code>3</code></td>
- <td>The size of the <em>Length of Link Name</em>
- field is 8 bytes.
- </td>
- </tr>
- </table>
- </td>
- </tr>
- <tr>
- <td align="center"><code>2</code></td>
- <td>Creation Order Field Present: if set, the <em>Creation
- Order</em> field is present. If not set, creation order
- information is not stored for links in this group.
- </td>
- </tr>
- <tr>
- <td align="center"><code>3</code></td>
- <td>Link Type Field Present: if set, the link is not
- a hard link and the <em>Link Type</em> field is present.
- If not set, the link is a hard link.
- </td>
- </tr>
- <tr>
- <td align="center"><code>4</code></td>
- <td>Link Name Character Set Field Present: if set, the
- link name is not represented with the ASCII character
- set and the <em>Link Name Character Set</em> field is
- present. If not set, the link name is represented with
- the ASCII character set.
- </td>
- </tr>
- <tr>
- <td align="center"><code>5-7</code></td>
- <td>Reserved (zero).
- </td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>Link type</p></td>
- <td><p>This is the link class type and can be one of the following
- values:
+ <th width="20%" align="center">Bits</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0-1</code></td>
+ <td>Determines the size of the <em>Length of Link Name</em>
+ field.
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>The size of the <em>Length of Link Name</em> field is
+ 1 byte.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>The size of the <em>Length of Link Name</em> field is
+ 2 bytes.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>The size of the <em>Length of Link Name</em> field is
+ 4 bytes.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>The size of the <em>Length of Link Name</em> field is
+ 8 bytes.
+ </td>
+ </tr>
+ </table>
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>Creation Order Field Present: if set, the <em>Creation
+ Order</em> field is present. If not set, creation order information
+ is not stored for links in this group.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>Link Type Field Present: if set, the link is not a hard
+ link and the <em>Link Type</em> field is present. If not set, the
+ link is a hard link.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>4</code></td>
+ <td>Link Name Character Set Field Present: if set, the link
+ name is not represented with the ASCII character set and the <em>Link
+ Name Character Set</em> field is present. If not set, the link name
+ is represented with the ASCII character set.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>5-7</code></td>
+ <td>Reserved (zero).</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Link type</p></td>
+ <td><p>This is the link class type and can be one of the
+ following values:</p>
<table class="list">
<tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>A hard link (should never be stored in the file)
- </td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td>A soft link.
- </td>
- </tr>
- <tr>
- <td align="center"><code>2-63</code></td>
- <td>Reserved for future HDF5 internal use.
- </td>
- </tr>
- <tr>
- <td align="center"><code>64</code></td>
- <td>An external link.
- </td>
- </tr>
- <tr>
- <td align="center"><code>65-255</code></td>
- <td>Reserved, but available for user-defined link types.
- </td>
- </tr>
- </table></p>
-
- <p>This field is present if bit 3 of <em>Flags</em> is set.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Creation Order</p></td>
- <td><p>This 64-bit value is an index of the link&rsquo;s creation time within
- the group. Values start at 0 when the group is created an increment
- by one for each link added to the group. Removing a link from a
- group does not change existing links&rsquo; creation order field.
- </p>
- <p>This field is present if bit 2 of <em>Flags</em> is set.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Link Name Character Set</p></td>
- <td><p>This is the character set for encoding the link&rsquo;s name:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>ASCII character set encoding (this should never be stored
- in the file)
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>UTF-8 character set encoding
- </td>
- </tr>
- </table></p>
-
- <p>This field is present if bit 4 of <em>Flags</em> is set.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Length of link name</p></td>
- <td><p>This is the length of the link&rsquo;s name. The size of this field
- depends on bits 0 and 1 of <em>Flags</em>.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Link name</p></td>
- <td><p>This is the name of the link, non-NULL terminated.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Link information</p></td>
- <td><p>The format of this field depends on the <em>link type</em>.</p>
- <p>For <b>hard</b> links, the field is formatted as follows:
-
- <table class="list">
- <tr>
- <td width="20%"><i>Size of Offsets</i> bytes:</td>
- <td width="80%">The address of the object header for the object that the
- link points to.
- </td>
- </tr>
- </table>
- </p>
-
- <p>
- For <b>soft</b> links, the field is formatted as follows:
-
- <table class="list">
- <tr>
- <td width="20%">Bytes 1-2:</td>
- <td width="80%">Length of soft link value.</td>
- </tr>
- <tr>
- <td><em>Length of soft link value</em> bytes:</td>
- <td>A non-NULL-terminated string storing the value of the
- soft link.
- </td>
- </tr>
- </table>
- </p>
-
- <p>
- For <b>external</b> links, the field is formatted as follows:
-
- <table class="list">
- <tr>
- <td width="20%">Bytes 1-2:</td>
- <td width="80%">Length of external link value.</td>
- </tr>
- <tr>
- <td><em>Length of external link value</em> bytes:</td>
- <td>The first byte contains the version number in the
- upper 4 bits and flags in the lower 4 bits for the external
- link. Both version and flags are defined to be zero in
- this document. The remaining bytes consist of two
- NULL-terminated strings, with no padding between them.
- The first string is the name of the HDF5 file containing
- the object linked to and the second string is the full path
- to the object linked to, within the HDF5 file&rsquo;s
- group hierarchy.
- </td>
- </tr>
- </table>
- </p>
-
- <p>
- For <b>user-defined</b> links, the field is formatted as follows:
-
- <table class="list">
- <tr>
- <td width="20%">Bytes 1-2:</td>
- <td width="80%">Length of user-defined data.</td>
- </tr>
- <tr>
- <td><em>Length of user-defined link value</em> bytes:</td>
- <td>The data supplied for the user-defined link type.</td>
- </tr>
- </table>
- </p>
-
- </td>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>A hard link (should never be stored in the file)</td>
+ </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>A soft link.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>2-63</code></td>
+ <td>Reserved for future HDF5 internal use.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>64</code></td>
+ <td>An external link.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>65-255</code></td>
+ <td>Reserved, but available for user-defined link types.</td>
+ </tr>
+ </table>
+ <p></p>
+
+ <p>
+ This field is present if bit 3 of <em>Flags</em> is set.
+ </p></td>
</tr>
- </table>
- </div>
+
+ <tr>
+ <td><p>Creation Order</p></td>
+ <td><p>This 64-bit value is an index of the link&rsquo;s
+ creation time within the group. Values start at 0 when the group is
+ created an increment by one for each link added to the group.
+ Removing a link from a group does not change existing links&rsquo;
+ creation order field.</p>
+ <p>
+ This field is present if bit 2 of <em>Flags</em> is set.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Link Name Character Set</p></td>
+ <td><p>This is the character set for encoding the
+ link&rsquo;s name:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>ASCII character set encoding (this should never be stored
+ in the file)</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>UTF-8 character set encoding</td>
+ </tr>
+ </table>
+ <p></p>
+
+ <p>
+ This field is present if bit 4 of <em>Flags</em> is set.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Length of link name</p></td>
+ <td><p>
+ This is the length of the link&rsquo;s name. The size of this field
+ depends on bits 0 and 1 of <em>Flags</em>.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Link name</p></td>
+ <td><p>This is the name of the link, non-NULL terminated.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Link information</p></td>
+ <td><p>
+ The format of this field depends on the <em>link type</em>.
+ </p>
+ <p>
+ For <b>hard</b> links, the field is formatted as follows:
+
+ </p>
+ <table class="list">
+ <tr>
+ <td width="20%"><i>Size of Offsets</i> bytes:</td>
+ <td width="80%">The address of the object header for the
+ object that the link points to.</td>
+ </tr>
+ </table>
+ <p></p>
+
+ <p>
+ For <b>soft</b> links, the field is formatted as follows:
+
+ </p>
+ <table class="list">
+ <tr>
+ <td width="20%">Bytes 1-2:</td>
+ <td width="80%">Length of soft link value.</td>
+ </tr>
+ <tr>
+ <td><em>Length of soft link value</em> bytes:</td>
+ <td>A non-NULL-terminated string storing the value of the
+ soft link.</td>
+ </tr>
+ </table>
+ <p></p>
+
+ <p>
+ For <b>external</b> links, the field is formatted as follows:
+
+ </p>
+ <table class="list">
+ <tr>
+ <td width="20%">Bytes 1-2:</td>
+ <td width="80%">Length of external link value.</td>
+ </tr>
+ <tr>
+ <td><em>Length of external link value</em> bytes:</td>
+ <td>The first byte contains the version number in the upper 4
+ bits and flags in the lower 4 bits for the external link. Both
+ version and flags are defined to be zero in this document. The
+ remaining bytes consist of two NULL-terminated strings, with no
+ padding between them. The first string is the name of the HDF5
+ file containing the object linked to and the second string is the
+ full path to the object linked to, within the HDF5 file&rsquo;s
+ group hierarchy.</td>
+ </tr>
+ </table>
+ <p></p>
+
+ <p>
+ For <b>user-defined</b> links, the field is formatted as follows:
+
+ </p>
+ <table class="list">
+ <tr>
+ <td width="20%">Bytes 1-2:</td>
+ <td width="80%">Length of user-defined data.</td>
+ </tr>
+ <tr>
+ <td><em>Length of user-defined link value</em> bytes:</td>
+ <td>The data supplied for the user-defined link type.</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="ExternalFileListMessage">IV.A.2.h. The Data Storage -
-External Data Files Message</a></h4>
+<h4>
+ <a name="ExternalFileListMessage">IV.A.2.h. The Data Storage -
+ External Data Files Message</a>
+</h4>
- <!-- start msgdesc table -->
- <center>
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> External
- Data Files</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0007</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>The external data storage message indicates that the data
- for an object is stored outside the HDF5 file. The filename of
- the object is stored as a Universal Resource Location (URL) of
- the actual filename containing the data. An external file list
- record also contains the byte offset of the start of the data
- within the file and the amount of space reserved in the file
- for that data.</td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- External File List Message
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td colspan="3">Reserved (zero)</td>
- </tr>
-
- <tr>
- <td colspan="2">Allocated Slots</td>
- <td colspan="2">Used Slots</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Heap Address<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Slot Definitions...<br /><br /></td>
- </tr>
- </table>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> External Data Files</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0007</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>The external data storage message indicates that the data
+ for an object is stored outside the HDF5 file. The filename of the
+ object is stored as a Universal Resource Location (URL) of the
+ actual filename containing the data. An external file list record
+ also contains the byte offset of the start of the data within the
+ file and the amount of space reserved in the file for that data.</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
+
+<div align="center">
+ <table class="format">
+ <caption>External File List Message</caption>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
- </div>
+ <tr>
+ <td>Version</td>
+ <td colspan="3">Reserved (zero)</td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td>
- <p>The version number information is used for changes in the format of
- External Data Storage Message and is described here:
- <table class="list">
- <tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
- </tr>
- <tr>
- <td align="center"><code>0</code></td>
- <td>Never used.</td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td>The current version used by the library.</td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>Allocated Slots</p></td>
- <td>
- <p>The total number of slots allocated in the message. Its value must be at least as
- large as the value contained in the Used Slots field. (The current library simply
- uses the number of Used Slots for this message)</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Used Slots</p></td>
- <td>
- <p>The number of initial slots which contains valid information.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Heap Address</p></td>
- <td>
- <p>This is the address of a local heap which contains the names for the external
- files (The local heap information can be found in Disk Format Level 1D in this
- document). The name at offset zero in the heap is always the empty string.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Slot Definitions</p></td>
- <td>
- <p>The slot definitions are stored in order according to the array addresses they
- represent.</p>
- </td>
- </tr>
-
- </table>
- </div>
+ <tr>
+ <td colspan="2">Allocated Slots</td>
+ <td colspan="2">Used Slots</td>
+ </tr>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- External File List Slot
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td colspan="4"><br />Name Offset in Local Heap<sup>L</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Offset in External Data File<sup>L</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Data Size in External File<sup>L</sup><br /><br /></td>
- </tr>
- </table>
+ <tr>
+ <td colspan="4"><br />Heap Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td colspan="4"><br />Slot Definitions...<br />
+ <br /></td>
+ </tr>
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Name Offset in Local Heap</p></td>
- <td>
- <p>The byte offset within the local name heap for the name
- of the file. File names are stored as a URL which has a
- protocol name, a host name, a port number, and a file
- name:
- <code><em>protocol</em>:<em>port</em>//<em>host</em>/<em>file</em></code>.
- If the protocol is omitted then &ldquo;file:&rdquo; is assumed. If
- the port number is omitted then a default port for that
- protocol is used. If both the protocol and the port
- number are omitted then the colon can also be omitted. If
- the double slash and host name are omitted then
- &ldquo;localhost&rdquo; is assumed. The file name is the only
- mandatory part, and if the leading slash is missing then
- it is relative to the application&rsquo;s current working
- directory (the use of relative names is not
- recommended).
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Offset in External Data File</p></td>
- <td>
- <p>This is the byte offset to the start of the data in the
- specified file. For files that contain data for a single
- dataset this will usually be zero.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Data Size in External File</p></td>
- <td>
- <p>This is the total number of bytes reserved in the
- specified file for raw data storage. For a file that
- contains exactly one complete dataset which is not
- extendable, the size will usually be the exact size of the
- dataset. However, by making the size larger one allows
- HDF5 to extend the dataset. The size can be set to a value
- larger than the entire file since HDF5 will read zeroes
- past the end of the file without failing.</p>
- </td>
- </tr>
- </table>
- </div>
-
-
-<br />
-<h4><a name="LayoutMessage">IV.A.2.i. The Data Storage - Layout
-Message</a></h4>
-
- <!-- start msgdesc table -->
- <center>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>The version number information is used for changes in the
+ format of External Data Storage Message and is described here:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Never used.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>The current version used by the library.</td>
+ </tr>
+ </table>
+ <p></p>
+
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Allocated Slots</p></td>
+ <td>
+ <p>The total number of slots allocated in the message. Its value
+ must be at least as large as the value contained in the Used Slots
+ field. (The current library simply uses the number of Used Slots
+ for this message)</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Used Slots</p></td>
+ <td>
+ <p>The number of initial slots which contains valid information.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Heap Address</p></td>
+ <td>
+ <p>This is the address of a local heap which contains the names
+ for the external files (The local heap information can be found in
+ Disk Format Level 1D in this document). The name at offset zero in
+ the heap is always the empty string.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Slot Definitions</p></td>
+ <td>
+ <p>The slot definitions are stored in order according to the
+ array addresses they represent.</p>
+ </td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="format">
+ <caption>External File List Slot</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Name Offset in Local Heap<sup>L</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Offset in External Data File<sup>L</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Data Size in External File<sup>L</sup><br />
+ <br /></td>
+ </tr>
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;L&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Lengths&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
+
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Name Offset in Local Heap</p></td>
+ <td>
+ <p>
+ The byte offset within the local name heap for the name of the
+ file. File names are stored as a URL which has a protocol name, a
+ host name, a port number, and a file name:
+ <code>
+ <em>protocol</em>:<em>port</em>//<em>host</em>/<em>file</em>
+ </code>
+ . If the protocol is omitted then &ldquo;file:&rdquo; is assumed.
+ If the port number is omitted then a default port for that protocol
+ is used. If both the protocol and the port number are omitted then
+ the colon can also be omitted. If the double slash and host name
+ are omitted then &ldquo;localhost&rdquo; is assumed. The file name
+ is the only mandatory part, and if the leading slash is missing
+ then it is relative to the application&rsquo;s current working
+ directory (the use of relative names is not recommended).
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Offset in External Data File</p></td>
+ <td>
+ <p>This is the byte offset to the start of the data in the
+ specified file. For files that contain data for a single dataset
+ this will usually be zero.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Data Size in External File</p></td>
+ <td>
+ <p>This is the total number of bytes reserved in the specified
+ file for raw data storage. For a file that contains exactly one
+ complete dataset which is not extendable, the size will usually be
+ the exact size of the dataset. However, by making the size larger
+ one allows HDF5 to extend the dataset. The size can be set to a
+ value larger than the entire file since HDF5 will read zeroes past
+ the end of the file without failing.</p>
+ </td>
+ </tr>
+ </table>
+</div>
+
+
+<br />
+<h4>
+ <a name="LayoutMessage">IV.A.2.i. The Data Storage - Layout Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Data Storage -
- Layout</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0008</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies</td></tr>
- <tr><td colspan="2"><b>Status:</b> Required for datasets; may not
- be repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>Data layout describes how the elements of a multi-dimensional
- array are stored in the HDF5 file. Three types of data layout
- are supported:
- <ol>
- <li>Contiguous: The array is stored in one contiguous area of
- the file. This layout requires that the size of the array be
- constant: data manipulations such as chunking, compression,
- checksums, or encryption are not permitted. The message stores
- the total storage size of the array. The offset of an element
- from the beginning of the storage area is computed as in a C
- array.</li>
- <li>Chunked: The array domain is regularly decomposed into
- chunks, and each chunk is allocated and stored separately. This
- layout supports arbitrary element traversals, compression,
- encryption, and checksums. (these features are described
- in other messages). The message stores the size of a chunk
- instead of the size of the entire array; the storage size of
- the entire array can be calculated by traversing the B-tree
- that stores the chunk addresses.</li>
- <li>Compact: The array is stored in one contiguous block, as
- part of this object header message.</li>
- </ol></td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Data Layout Message (Versions 1 and 2)
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Dimensionality</td>
- <td>Layout Class</td>
- <td>Reserved <em>(zero)</em></td>
- </tr>
-
- <tr>
- <td colspan="4">Reserved <em>(zero)</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Data Address<sup>O</sup> <em>(optional)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4">Dimension 0 Size</td>
- </tr>
-
- <tr>
- <td colspan="4">Dimension 1 Size</td>
- </tr>
-
- <tr>
- <td colspan="4">...</td>
- </tr>
-
- <tr>
- <td colspan="4">Dimension #n Size</td>
- </tr>
-
- <tr>
- <td colspan="4">Dataset Element Size <em>(optional)</em></td>
- </tr>
-
- <tr>
- <td colspan="4">Compact Data Size <em>(optional)</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Compact Data... <em>(variable size, optional)</em><br /><br /></td>
- </tr>
- </table>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Data Storage -
+ Layout</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0008</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Required for datasets; may not be
+ repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>Data layout describes how the elements of a
+ multi-dimensional array are stored in the HDF5 file. Three types of
+ data layout are supported:
+ <ol>
+ <li>Contiguous: The array is stored in one contiguous area of
+ the file. This layout requires that the size of the array be
+ constant: data manipulations such as chunking, compression,
+ checksums, or encryption are not permitted. The message stores the
+ total storage size of the array. The offset of an element from the
+ beginning of the storage area is computed as in a C array.</li>
+ <li>Chunked: The array domain is regularly decomposed into
+ chunks, and each chunk is allocated and stored separately. This
+ layout supports arbitrary element traversals, compression,
+ encryption, and checksums. (these features are described in other
+ messages). The message stores the size of a chunk instead of the
+ size of the entire array; the storage size of the entire array can
+ be calculated by traversing the B-tree that stores the chunk
+ addresses.</li>
+ <li>Compact: The array is stored in one contiguous block, as
+ part of this object header message.</li>
+ </ol>
+ </td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
+
+<div align="center">
+ <table class="format">
+ <caption>Data Layout Message (Versions 1 and 2)</caption>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
- </div>
+ <tr>
+ <td>Version</td>
+ <td>Dimensionality</td>
+ <td>Layout Class</td>
+ <td>Reserved <em>(zero)</em></td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td>
- <p>The version number information is used for changes in the format of the data
- layout message and is described here:
- <table class="list">
- <tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Never used.</td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>Used by version 1.4 and before of the library to encode layout information.
- Data space is always allocated when the data set is created.</td>
- </tr>
-
- <tr>
- <td align="center"><code>2</code></td>
- <td>Used by version 1.6.x of the library to encode layout information.
- Data space is allocated only when it is necessary.</td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimensionality</p></td>
- <td><p>An array has a fixed dimensionality. This field
- specifies the number of dimension size fields later in the
- message. The value stored for chunked storage is 1 greater than
- the number of dimensions in the dataset&rsquo;s dataspace.
- For example, 2 is stored for a 1 dimensional dataset.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Layout Class</p></td>
- <td><p>The layout class specifies the type of storage for the data
- and how the other fields of the layout message are to be
- interpreted.
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Compact Storage
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>Contiguous Storage
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>2</code></td>
- <td>Chunked Storage
- </td>
- </tr>
- </table>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Data Address</p></td>
- <td><p>For contiguous storage, this is the address of the raw
- data in the file. For chunked storage this is the address
- of the v1 B-tree that is used to look up the addresses of the
- chunks. This field is not present for compact storage.
- If the version for this message is greater than 1, the address
- may have the &ldquo;undefined address&rdquo; value, to indicate that
- storage has not yet been allocated for this array.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dimension #n Size</p></td>
- <td><p>For contiguous and compact storage the dimensions define
- the entire size of the array while for chunked storage they define
- the size of a single chunk. In all cases, they are in units of
- array elements (not bytes). The first dimension stored in the list
- of dimensions is the slowest changing dimension and the last
- dimension stored is the fastest changing dimension.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dataset Element Size</p></td>
- <td><p>The size of a dataset element, in bytes. This field is only
- present for chunked storage.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Compact Data Size</p></td>
- <td><p>This field is only present for compact data storage.
- It contains the size of the raw data for the dataset array, in
- bytes.</p>
- </td>
- </tr>
+ <tr>
+ <td colspan="4">Reserved <em>(zero)</em></td>
+ </tr>
- <tr>
- <td><p>Compact Data</p></td>
- <td><p>This field is only present for compact data storage.
- It contains the raw data for the dataset array.</p>
- </td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4"><br />Data Address<sup>O</sup> <em>(optional)</em><br />
+ <br /></td>
+ </tr>
- <br />
- <p>Version 3 of this message re-structured the format into specific
- properties that are required for each layout class.</p>
-
-
- <div align="center">
- <table class="format">
- <caption>
- <b>Data Layout Message (Version 3)</b>
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Layout Class</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Properties <em>(variable size)</em><br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4">Dimension 0 Size</td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td>
- <p>The version number information is used for changes in the format of layout message
- and is described here:
- <table class="list">
- <tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>3</code></td>
- <td>Used by the version 1.6.3 and later of the library to store properties
- for each layout class.</td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Layout Class</p></td>
- <td><p>The layout class specifies the type of storage for the data
- and how the other fields of the layout message are to be
- interpreted.
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Compact Storage
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>Contiguous Storage
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>2</code></td>
- <td>Chunked Storage
- </td>
- </tr>
- </table>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Properties</p></td>
- <td><p>This variable-sized field encodes information specific to each
- layout class and is described below. If there is no property
- information specified for a layout class, the size of this field
- is zero bytes.</p></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4">Dimension 1 Size</td>
+ </tr>
- <br />
- <p>Class-specific information for compact layout (Class 0): (Note: The dimensionality information
- is in the Dataspace message)</p>
-
-
- <div align="center">
- <table class="format">
- <caption>
- Compact Storage Property Description
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td colspan="2">Size</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Raw Data... <em>(variable size)</em><br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4">...</td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Size</p></td>
- <td><p>This field contains the size of the raw data for the dataset
- array, in bytes.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Raw Data</p></td>
- <td><p>This field contains the raw data for the dataset array.</p></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4">Dimension #n Size</td>
+ </tr>
+ <tr>
+ <td colspan="4">Dataset Element Size <em>(optional)</em></td>
+ </tr>
- <br />
- <p>Class-specific information for contiguous layout (Class 1): (Note: The dimensionality information
- is in the Dataspace message)</p>
-
-
- <div align="center">
- <table class="format">
- <caption>
- Contiguous Storage Property Description
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td colspan="4"><br />Address<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Size<sup>L</sup><br /><br /></td>
- </tr>
- </table>
+ <tr>
+ <td colspan="4">Compact Data Size <em>(optional)</em></td>
+ </tr>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <td colspan="4"><br />Compact Data... <em>(variable size,
+ optional)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+
+ <table class="note">
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Address</p></td>
- <td><p>This is the address of the raw data in the file.
- The address may have the &ldquo;undefined address&rdquo; value, to indicate
- that storage has not yet been allocated for this array.</p></td>
- </tr>
-
- <tr>
- <td><p>Size</p></td>
- <td><p>This field contains the size allocated to store the raw data,
- in bytes.
- </p>
- </td>
- </tr>
- </table>
- </div>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>The version number information is used for changes in the
+ format of the data layout message and is described here:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
- <br />
- <p>Class-specific information for chunked layout (Class 2):</p>
-
-
- <div align="center">
- <table class="format">
- <caption>
- Chunked Storage Property Description
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Dimensionality</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Address<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4">Dimension 0 Size</td>
- </tr>
-
- <tr>
- <td colspan="4">Dimension 1 Size</td>
- </tr>
-
- <tr>
- <td colspan="4">...</td>
- </tr>
-
- <tr>
- <td colspan="4">Dimension #n Size</td>
- </tr>
-
- <tr>
- <td colspan="4">Dataset Element Size</td>
- </tr>
- </table>
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Never used.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>Used by version 1.4 and before of the library to encode
+ layout information. Data space is always allocated when the data
+ set is created.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>Used by version 1.6.x of the library to encode layout
+ information. Data space is allocated only when it is necessary.</td>
+ </tr>
+ </table>
+ <p></p>
+ </td>
+ </tr>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td><p>Dimensionality</p></td>
+ <td><p>An array has a fixed dimensionality. This field
+ specifies the number of dimension size fields later in the message.
+ The value stored for chunked storage is 1 greater than the number
+ of dimensions in the dataset&rsquo;s dataspace. For example, 2 is
+ stored for a 1 dimensional dataset.</p></td>
+ </tr>
- </div>
+ <tr>
+ <td><p>Layout Class</p></td>
+ <td><p>The layout class specifies the type of storage for
+ the data and how the other fields of the layout message are to be
+ interpreted.</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Dimensionality</p></td>
- <td><p>A chunk has a fixed dimensionality. This field specifies
- the number of dimension size fields later in the message.</p></td>
- </tr>
-
- <tr>
- <td><p>Address</p></td>
- <td><p>This is the address of the v1 B-tree that is used to look up the
- addresses of the chunks that actually store portions of the array
- data. The address may have the &ldquo;undefined address&rdquo; value, to
- indicate that storage has not yet been allocated for this array.</p></td>
- </tr>
-
- <tr>
- <td><p>Dimension #n Size</p></td>
- <td><p>These values define the dimension size of a single chunk, in
- units of array elements (not bytes). The first dimension stored in
- the list of dimensions is the slowest changing dimension and the
- last dimension stored is the fastest changing dimension.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dataset Element Size</p></td>
- <td><p>The size of a dataset element, in bytes.
- </p>
- </td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Compact Storage</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>Contiguous Storage</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>Chunked Storage</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Data Address</p></td>
+ <td><p>For contiguous storage, this is the address of the
+ raw data in the file. For chunked storage this is the address of
+ the v1 B-tree that is used to look up the addresses of the chunks.
+ This field is not present for compact storage. If the version for
+ this message is greater than 1, the address may have the
+ &ldquo;undefined address&rdquo; value, to indicate that storage has
+ not yet been allocated for this array.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Dimension #n Size</p></td>
+ <td><p>For contiguous and compact storage the dimensions
+ define the entire size of the array while for chunked storage they
+ define the size of a single chunk. In all cases, they are in units
+ of array elements (not bytes). The first dimension stored in the
+ list of dimensions is the slowest changing dimension and the last
+ dimension stored is the fastest changing dimension.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Dataset Element Size</p></td>
+ <td><p>The size of a dataset element, in bytes. This field
+ is only present for chunked storage.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Compact Data Size</p></td>
+ <td><p>This field is only present for compact data storage.
+ It contains the size of the raw data for the dataset array, in
+ bytes.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Compact Data</p></td>
+ <td><p>This field is only present for compact data storage.
+ It contains the raw data for the dataset array.</p></td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="BogusMessage">IV.A.2.j. The Bogus Message</a></h4>
+<p>Version 3 of this message re-structured the format into specific
+ properties that are required for each layout class.</p>
- <!-- start msgdesc table -->
- <center>
+
+<div align="center">
+ <table class="format">
+ <caption>
+ <b>Data Layout Message (Version 3)</b>
+ </caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td>Layout Class</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Properties <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td>
+ <p>The version number information is used for changes in the
+ format of layout message and is described here:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>Used by the version 1.6.3 and later of the library to
+ store properties for each layout class.</td>
+ </tr>
+ </table>
+ <p></p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Layout Class</p></td>
+ <td><p>The layout class specifies the type of storage for
+ the data and how the other fields of the layout message are to be
+ interpreted.</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Compact Storage</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>Contiguous Storage</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>Chunked Storage</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Properties</p></td>
+ <td><p>This variable-sized field encodes information
+ specific to each layout class and is described below. If there is
+ no property information specified for a layout class, the size of
+ this field is zero bytes.</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<p>Class-specific information for compact layout (Class 0): (Note:
+ The dimensionality information is in the Dataspace message)</p>
+
+
+<div align="center">
+ <table class="format">
+ <caption>Compact Storage Property Description</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="2">Size</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Raw Data... <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Size</p></td>
+ <td><p>This field contains the size of the raw data for the
+ dataset array, in bytes.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Raw Data</p></td>
+ <td><p>This field contains the raw data for the dataset
+ array.</p></td>
+ </tr>
+ </table>
+</div>
+
+
+<br />
+<p>Class-specific information for contiguous layout (Class 1):
+ (Note: The dimensionality information is in the Dataspace message)</p>
+
+
+<div align="center">
+ <table class="format">
+ <caption>Contiguous Storage Property Description</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Size<sup>L</sup><br />
+ <br /></td>
+ </tr>
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ <tr>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
+
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Address</p></td>
+ <td><p>This is the address of the raw data in the file. The
+ address may have the &ldquo;undefined address&rdquo; value, to
+ indicate that storage has not yet been allocated for this array.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Size</p></td>
+ <td><p>This field contains the size allocated to store the
+ raw data, in bytes.</p></td>
+ </tr>
+ </table>
+</div>
+
+
+<br />
+<p>Class-specific information for chunked layout (Class 2):</p>
+
+
+<div align="center">
+ <table class="format">
+ <caption>Chunked Storage Property Description</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Dimensionality</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Dimension 0 Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Dimension 1 Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">...</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Dimension #n Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Dataset Element Size</td>
+ </tr>
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
+
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Dimensionality</p></td>
+ <td><p>A chunk has a fixed dimensionality. This field
+ specifies the number of dimension size fields later in the message.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Address</p></td>
+ <td><p>This is the address of the v1 B-tree that is used to
+ look up the addresses of the chunks that actually store portions of
+ the array data. The address may have the &ldquo;undefined
+ address&rdquo; value, to indicate that storage has not yet been
+ allocated for this array.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Dimension #n Size</p></td>
+ <td><p>These values define the dimension size of a single
+ chunk, in units of array elements (not bytes). The first dimension
+ stored in the list of dimensions is the slowest changing dimension
+ and the last dimension stored is the fastest changing dimension.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Dataset Element Size</p></td>
+ <td><p>The size of a dataset element, in bytes.</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="BogusMessage">IV.A.2.j. The Bogus Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Bogus</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0009</td></tr>
- <tr><td colspan="2"><b>Length:</b> 4 bytes</td></tr>
- <tr><td colspan="2"><b>Status:</b> For testing only; should never
- be stored in a valid file.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>This message is used for testing the HDF5 Library&rsquo;s
- response to an &ldquo;unknown&rdquo; message type and should
- never be encountered in a valid HDF5 file.</td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Bogus Message
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td colspan="4">Bogus Value</td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Bogus</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0009</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> 4 bytes</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> For testing only; should never be
+ stored in a valid file.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>This message is used for testing the HDF5 Library&rsquo;s
+ response to an &ldquo;unknown&rdquo; message type and should never
+ be encountered in a valid HDF5 file.</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Bogus Value</p></td>
- <td>
- <p>This value should always be: <code>0xdeadbeef</code>.</p>
- </td>
- </tr>
- </table>
- </div>
+<div align="center">
+ <table class="format">
+ <caption>Bogus Message</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="4">Bogus Value</td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="GroupInfoMessage">IV.A.2.k. The Group Info Message
-</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Bogus Value</p></td>
+ <td>
+ <p>
+ This value should always be:
+ <code>0xdeadbeef</code>
+ .
+ </p>
+ </td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="GroupInfoMessage">IV.A.2.k. The Group Info Message </a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Group Info</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x000A</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td><p>This message stores information for the constants defining
- a &ldquo;new style&rdquo; group&rsquo;s behavior. Constant
- information will be stored in this message and variable
- information will be stored in the
- <a href="#LinkInfoMessage">Link Info</a> message.</p>
- <p>Note: the &ldquo;estimated entry&rdquo; information below is
- used when determining the size of the object header for the
- group when it is created.</p></td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Group Info Message
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Flags</td>
- <td colspan="2">Link Phase Change: Maximum Compact Value <em>(optional)</em></td>
- </tr>
- <tr>
- <td colspan="2">Link Phase Change: Minimum Dense Value <em>(optional)</em></td>
- <td colspan="2">Estimated Number of Entries <em>(optional)</em></td>
- </tr>
- <tr>
- <td colspan="2">Estimated Link Name Length of Entries <em>(optional)</em></td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Group Info</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x000A</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td><p>
+ This message stores information for the constants defining a
+ &ldquo;new style&rdquo; group&rsquo;s behavior. Constant
+ information will be stored in this message and variable information
+ will be stored in the <a href="#LinkInfoMessage">Link Info</a>
+ message.
+ </p>
+ <p>Note: the &ldquo;estimated entry&rdquo; information below is
+ used when determining the size of the object header for the group
+ when it is created.</p></td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- </table>
- </div>
+<div align="center">
+ <table class="format">
+ <caption>Group Info Message</caption>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number for this message. This document describes version 0.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Flags</p></td>
- <td><p>This is the group information flag with the following definition:
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>If set, link phase change values are stored.
- </td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td>If set, the estimated entry information is non-default
- and is stored.
- </td>
- </tr>
- <tr>
- <td align="center"><code>2-7</code></td>
- <td>Reserved</td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Link Phase Change: Maximum Compact Value</p></td>
- <td><p>The is the maximum number of links to store &ldquo;compactly&rdquo; (in
- the group&rsquo;s object header).</p>
- <p>This field is present if bit 0 of <em>Flags</em> is set.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Link Phase Change: Minimum Dense Value</p></td>
- <td><p>This is the minimum number of links to store &ldquo;densely&rdquo; (in
- the group&rsquo;s fractal heap). The fractal heap&rsquo;s address is
- located in the <a href="#LinkInfoMessage">Link Info</a>
- message.</p>
- <p>This field is present if bit 0 of <em>Flags</em> is set.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Estimated Number of Entries</p></td>
- <td><p>This is the estimated number of entries in groups.</p>
- <p>If this field is not present, the default value of <code>4</code>
- will be used for the estimated number of group entries.</p>
- <p>This field is present if bit 1 of <em>Flags</em> is set.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Estimated Link Name Length of Entries</p></td>
- <td><p>This is the estimated length of entry name.</p>
- <p>If this field is not present, the default value of <code>8</code>
- will be used for the estimated link name length of group entries.</p>
- <p>This field is present if bit 1 of <em>Flags</em> is set.</p>
- </td>
- </tr>
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
- </table>
- </div>
- </p>
+ <tr>
+ <td>Version</td>
+ <td>Flags</td>
+ <td colspan="2">Link Phase Change: Maximum Compact Value <em>(optional)</em></td>
+ </tr>
+ <tr>
+ <td colspan="2">Link Phase Change: Minimum Dense Value <em>(optional)</em></td>
+ <td colspan="2">Estimated Number of Entries <em>(optional)</em></td>
+ </tr>
+ <tr>
+ <td colspan="2">Estimated Link Name Length of Entries <em>(optional)</em></td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ </table>
+</div>
<br />
-<h4><a name="FilterMessage">IV.A.2.l. The Data Storage - Filter
-Pipeline Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number for this message. This document
+ describes version 0.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Flags</p></td>
+ <td><p>This is the group information flag with the following
+ definition:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>If set, link phase change values are stored.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>If set, the estimated entry information is non-default
+ and is stored.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>2-7</code></td>
+ <td>Reserved</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Link Phase Change: Maximum Compact Value</p></td>
+ <td><p>The is the maximum number of links to store
+ &ldquo;compactly&rdquo; (in the group&rsquo;s object header).</p>
+ <p>
+ This field is present if bit 0 of <em>Flags</em> is set.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Link Phase Change: Minimum Dense Value</p></td>
+ <td><p>
+ This is the minimum number of links to store &ldquo;densely&rdquo;
+ (in the group&rsquo;s fractal heap). The fractal heap&rsquo;s
+ address is located in the <a href="#LinkInfoMessage">Link Info</a>
+ message.
+ </p>
+ <p>
+ This field is present if bit 0 of <em>Flags</em> is set.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Estimated Number of Entries</p></td>
+ <td><p>This is the estimated number of entries in groups.</p>
+ <p>
+ If this field is not present, the default value of
+ <code>4</code>
+ will be used for the estimated number of group entries.
+ </p>
+ <p>
+ This field is present if bit 1 of <em>Flags</em> is set.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Estimated Link Name Length of Entries</p></td>
+ <td><p>This is the estimated length of entry name.</p>
+ <p>
+ If this field is not present, the default value of
+ <code>8</code>
+ will be used for the estimated link name length of group entries.
+ </p>
+ <p>
+ This field is present if bit 1 of <em>Flags</em> is set.
+ </p></td>
+ </tr>
+
+ </table>
+</div>
+<p></p>
+
+<br />
+<h4>
+ <a name="FilterMessage">IV.A.2.l. The Data Storage - Filter
+ Pipeline Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b>
- Data Storage - Filter Pipeline</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x000B</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td><p>This message describes the filter pipeline which should
- be applied to the data stream by providing filter identification
- numbers, flags, a name, and client data.</p>
- <p>This message may be present in the object headers of both
- dataset and group objects. For datasets, it specifies the
- filters to apply to raw data. For groups, it specifies the
- filters to apply to the group&rsquo;s fractal heap. Currently,
- only datasets using chunked data storage use the filter
- pipeline on their raw data.</p></td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Filter Pipeline Message - Version 1
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Number of Filters</td>
- <td colspan="2">Reserved (zero)</td>
- </tr>
-
- <tr>
- <td colspan="4">Reserved (zero)</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Filter Description List <em>(variable size)</em><br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Data Storage -
+ Filter Pipeline</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x000B</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td><p>This message describes the filter pipeline which
+ should be applied to the data stream by providing filter
+ identification numbers, flags, a name, and client data.</p>
+ <p>This message may be present in the object headers of both
+ dataset and group objects. For datasets, it specifies the filters
+ to apply to raw data. For groups, it specifies the filters to apply
+ to the group&rsquo;s fractal heap. Currently, only datasets using
+ chunked data storage use the filter pipeline on their raw data.</p></td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number for this message. This table
- describes version 1.</p></td>
- </tr>
-
- <tr>
- <td><p>Number of Filters</p></td>
- <td><p>The total number of filters described in this
- message. The maximum possible number of filters in a
- message is 32.</p></td>
- </tr>
-
- <tr>
- <td><p>Filter Description List</p></td>
- <td><p>A description of each filter. A filter description
- appears in the next table.</p></td>
- </tr>
- </table>
- </div>
+<div align="center">
+ <table class="format">
+ <caption>Filter Pipeline Message - Version 1</caption>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Filter Description
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td colspan="2">Filter Identification Value</td>
- <td colspan="2">Name Length</td>
- </tr>
-
- <tr>
- <td colspan="2">Flags</td>
- <td colspan="2">Number Client Data Values</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Name <em>(variable size, optional)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Client Data <em>(variable size, optional)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4">Padding <em>(variable size, optional)</em></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Filter Identification Value</p></td>
- <td>
- <p>
- This value, often referred to as a filter identifier,
- is designed to be a unique identifier for the filter.
- Values from zero through 32,767 are reserved for filters
- supported by The HDF Group in the HDF5 Library and for
- filters requested and supported by third parties.
- Filters supported by The HDF Group are documented immediately
- below. Information on 3rd-party filters can be found at
- The HDF Group&rsquo;s
- <a href="http://www.hdfgroup.org/services/contributions.html">
- Contributions</a> page.</p>
-
- <p>
- To request a filter identifier, please contact
- The HDF Group&rsquo;s Help Desk at
- <img src="Graphics/help.png" valign="middle" height="14"
- alt="The HDF Group Help Desk">.
- You will be asked to provide the following information:</p>
- <ol>
- <li>Contact information for the developer requesting the
- new identifier</li>
- <li>A short description of the new filter</li>
- <li>Links to any relevant information, including licensing
- information</li>
- </ol>
- <p>
- Values from 32768 to 65535 are reserved for non-distributed uses
- (for example, internal company usage) or for application usage
- when testing a feature. The HDF Group does not track or document
- the use of the filters with identifiers from this range.</p>
-
- <p>
- The filters currently in library version 1.8.0 are
- listed below:
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Identification</th>
- <th width="15%" align="left">Name</th>
- <th width="65%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>N/A</td>
- <td>Reserved</td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>deflate</td>
- <td>GZIP deflate compression</td>
- </tr>
-
- <tr>
- <td align="center"><code>2</code></td>
- <td>shuffle</td>
- <td>Data element shuffling</td>
- </tr>
-
- <tr>
- <td align="center"><code>3</code></td>
- <td>fletcher32</td>
- <td>Fletcher32 checksum</td>
- </tr>
-
- <tr>
- <td align="center"><code>4</code></td>
- <td>szip</td>
- <td>SZIP compression</td>
- </tr>
-
- <tr>
- <td align="center"><code>5</code></td>
- <td>nbit</td>
- <td>N-bit packing</td>
- </tr>
-
- <tr>
- <td align="center"><code>6</code></td>
- <td>scaleoffset</td>
- <td>Scale and offset encoded values</td>
- </tr>
- </table>
- </p></td>
- </tr>
-
- <tr>
- <td><p>Name Length</p></td>
- <td><p>Each filter has an optional null-terminated ASCII name
- and this field holds the length of the name including the
- null termination padded with nulls to be a multiple of
- eight. If the filter has no name then a value of zero is
- stored in this field.</p></td>
- </tr>
-
- <tr>
- <td><p>Flags</p></td>
- <td><p>The flags indicate certain properties for a filter. The
- bit values defined so far are:
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>If set then the filter is an optional filter.
- During output, if an optional filter fails it will be
- silently skipped in the pipeline.</td>
- </tr>
-
- <tr>
- <td align="center"><code>1-15</code></td>
- <td>Reserved (zero)</td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Number of Client Data Values</p></td>
- <td><p>Each filter can store integer values to control
- how the filter operates. The number of entries in the
- <em>Client Data</em> array is stored in this field.</p></td>
- </tr>
-
- <tr>
- <td><p>Name</p></td>
- <td><p>If the <em>Name Length</em> field is non-zero then it will
- contain the size of this field, padded to a multiple of eight. This
- field contains a null-terminated, ASCII character
- string to serve as a comment/name for the filter.</p></td>
- </tr>
-
- <tr>
- <td><p>Client Data</p></td>
- <td><p>This is an array of four-byte integers which will be
- passed to the filter function. The <em>Client Data Number</em> of
- Values determines the number of elements in the array.</p></td>
- </tr>
-
- <tr>
- <td><p>Padding</p></td>
- <td><p>Four bytes of zeroes are added to the message at this
- point if the Client Data Number of Values field contains
- an odd number.</p></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td>Version</td>
+ <td>Number of Filters</td>
+ <td colspan="2">Reserved (zero)</td>
+ </tr>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Filter Pipeline Message - Version 2
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Number of Filters</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Filter Description List <em>(variable size)</em><br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4">Reserved (zero)</td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number for this message. This table
- describes version 2.</p></td>
- </tr>
-
- <tr>
- <td><p>Number of Filters</p></td>
- <td><p>The total number of filters described in this
- message. The maximum possible number of filters in a
- message is 32.</p></td>
- </tr>
-
- <tr>
- <td><p>Filter Description List</p></td>
- <td><p>A description of each filter. A filter description
- appears in the next table.</p></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="4"><br />Filter Description List <em>(variable
+ size)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Filter Description
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td colspan="2">Filter Identification Value</td>
- <td colspan="2">Name Length <em>(optional)</em></td>
- </tr>
-
- <tr>
- <td colspan="2">Flags</td>
- <td colspan="2">Number Client Data Values</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Name <em>(variable size, optional)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Client Data <em>(variable size, optional)</em><br /><br /></td>
- </tr>
- </table>
- </div>
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Filter Identification Value</p></td>
- <td>
- <p>
- This value, often referred to as a filter identifier,
- is designed to be a unique identifier for the filter.
- Values from zero through 32,767 are reserved for filters
- supported by The HDF Group in the HDF5 Library and for
- filters requested and supported by third parties.
- Filters supported by The HDF Group are documented immediately
- below. Information on 3rd-party filters can be found at
- The HDF Group&rsquo;s
- <a href="http://www.hdfgroup.org/services/contributions.html">
- Contributions</a> page.</p>
-
- <p>
- To request a filter identifier, please contact
- The HDF Group&rsquo;s Help Desk at
- <img src="Graphics/help.png" valign="middle" height="14"
- alt="The HDF Group Help Desk">.
- You will be asked to provide the following information:</p>
- <ol>
- <li>Contact information for the developer requesting the
- new identifier</li>
- <li>A short description of the new filter</li>
- <li>Links to any relevant information, including licensing
- information</li>
- </ol>
- <p>
- Values from 32768 to 65535 are reserved for non-distributed uses
- (for example, internal company usage) or for application usage
- when testing a feature. The HDF Group does not track or document
- the use of the filters with identifiers from this range.</p>
-
- <p>
- The filters currently in library version 1.8.0 are
- listed below:
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Identification</th>
- <th width="15%" align="left">Name</th>
- <th width="65%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>N/A</td>
- <td>Reserved</td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>deflate</td>
- <td>GZIP deflate compression</td>
- </tr>
-
- <tr>
- <td align="center"><code>2</code></td>
- <td>shuffle</td>
- <td>Data element shuffling</td>
- </tr>
-
- <tr>
- <td align="center"><code>3</code></td>
- <td>fletcher32</td>
- <td>Fletcher32 checksum</td>
- </tr>
-
- <tr>
- <td align="center"><code>4</code></td>
- <td>szip</td>
- <td>SZIP compression</td>
- </tr>
-
- <tr>
- <td align="center"><code>5</code></td>
- <td>nbit</td>
- <td>N-bit packing</td>
- </tr>
-
- <tr>
- <td align="center"><code>6</code></td>
- <td>scaleoffset</td>
- <td>Scale and offset encoded values</td>
- </tr>
- </table>
- </p></td>
- </tr>
-
- <tr>
- <td><p>Name Length</p></td>
- <td><p>Each filter has an optional null-terminated ASCII name
- and this field holds the length of the name including the
- null termination padded with nulls to be a multiple of
- eight. If the filter has no name then a value of zero is
- stored in this field.</p>
- <p>Filters with IDs less than 256 (in other words, filters
- that are defined in this format documentation) do not store
- the <em>Name Length</em> or <em>Name</em> fields.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Flags</p></td>
- <td><p>The flags indicate certain properties for a filter. The
- bit values defined so far are:
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>If set then the filter is an optional filter.
- During output, if an optional filter fails it will be
- silently skipped in the pipeline.</td>
- </tr>
-
- <tr>
- <td align="center"><code>1-15</code></td>
- <td>Reserved (zero)</td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Number of Client Data Values</p></td>
- <td><p>Each filter can store integer values to control
- how the filter operates. The number of entries in the
- <em>Client Data</em> array is stored in this field.</p></td>
- </tr>
-
- <tr>
- <td><p>Name</p></td>
- <td><p>If the <em>Name Length</em> field is non-zero then it will
- contain the size of this field, <em>not</em> padded to a multiple
- of eight. This field contains a <em>non-</em>null-terminated,
- ASCII character string to serve as a comment/name for the filter.
- </p>
- <p>Filters that are defined in this format documentation
- such as deflate and shuffle do not store the <em>Name
- Length</em> or <em>Name</em> fields.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Client Data</p></td>
- <td><p>This is an array of four-byte integers which will be
- passed to the filter function. The Client Data Number of
- Values</em> determines the number of elements in the array.</p>
- </td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number for this message. This table
+ describes version 1.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Number of Filters</p></td>
+ <td><p>The total number of filters described in this
+ message. The maximum possible number of filters in a message is 32.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Filter Description List</p></td>
+ <td><p>A description of each filter. A filter description
+ appears in the next table.</p></td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="AttributeMessage">IV.A.2.m. The Attribute Message</a></h4>
+<div align="center">
+ <table class="format">
+ <caption>Filter Description</caption>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="2">Filter Identification Value</td>
+ <td colspan="2">Name Length</td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Flags</td>
+ <td colspan="2">Number Client Data Values</td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Name <em>(variable size, optional)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Client Data <em>(variable size,
+ optional)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Padding <em>(variable size, optional)</em></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Filter Identification Value</p></td>
+ <td>
+ <p>
+ This value, often referred to as a filter identifier, is designed
+ to be a unique identifier for the filter. Values from zero through
+ 32,767 are reserved for filters supported by The HDF Group in the
+ HDF5 Library and for filters requested and supported by third
+ parties. Filters supported by The HDF Group are documented
+ immediately below. Information on 3rd-party filters can be found at
+ The HDF Group&rsquo;s <a
+ href="http://www.hdfgroup.org/services/contributions.html">
+ Contributions</a> page.
+ </p>
+
+ <p>
+ To request a filter identifier, please contact The HDF
+ Group&rsquo;s Help Desk at <img src="Graphics/help.png"
+ valign="middle" height="14" alt="The HDF Group Help Desk">.
+ You will be asked to provide the following information:
+ </p>
+ <ol>
+ <li>Contact information for the developer requesting the new
+ identifier</li>
+ <li>A short description of the new filter</li>
+ <li>Links to any relevant information, including licensing
+ information</li>
+ </ol>
+ <p>Values from 32768 to 65535 are reserved for non-distributed
+ uses (for example, internal company usage) or for application usage
+ when testing a feature. The HDF Group does not track or document
+ the use of the filters with identifiers from this range.</p>
+
+ <p>The filters currently in library version 1.8.0 are listed
+ below:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Identification</th>
+ <th width="15%" align="left">Name</th>
+ <th width="65%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>N/A</td>
+ <td>Reserved</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>deflate</td>
+ <td>GZIP deflate compression</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>shuffle</td>
+ <td>Data element shuffling</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>fletcher32</td>
+ <td>Fletcher32 checksum</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>4</code></td>
+ <td>szip</td>
+ <td>SZIP compression</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>5</code></td>
+ <td>nbit</td>
+ <td>N-bit packing</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>6</code></td>
+ <td>scaleoffset</td>
+ <td>Scale and offset encoded values</td>
+ </tr>
+ </table>
+ <p></p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Name Length</p></td>
+ <td><p>Each filter has an optional null-terminated ASCII
+ name and this field holds the length of the name including the null
+ termination padded with nulls to be a multiple of eight. If the
+ filter has no name then a value of zero is stored in this field.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Flags</p></td>
+ <td><p>The flags indicate certain properties for a filter.
+ The bit values defined so far are:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>If set then the filter is an optional filter. During
+ output, if an optional filter fails it will be silently skipped
+ in the pipeline.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1-15</code></td>
+ <td>Reserved (zero)</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Number of Client Data Values</p></td>
+ <td><p>
+ Each filter can store integer values to control how the filter
+ operates. The number of entries in the <em>Client Data</em> array
+ is stored in this field.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Name</p></td>
+ <td><p>
+ If the <em>Name Length</em> field is non-zero then it will contain
+ the size of this field, padded to a multiple of eight. This field
+ contains a null-terminated, ASCII character string to serve as a
+ comment/name for the filter.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Client Data</p></td>
+ <td><p>
+ This is an array of four-byte integers which will be passed to the
+ filter function. The <em>Client Data Number</em> of Values
+ determines the number of elements in the array.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Padding</p></td>
+ <td><p>Four bytes of zeroes are added to the message at this
+ point if the Client Data Number of Values field contains an odd
+ number.</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Filter Pipeline Message - Version 2</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td>Number of Filters</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Filter Description List <em>(variable
+ size)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number for this message. This table
+ describes version 2.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Number of Filters</p></td>
+ <td><p>The total number of filters described in this
+ message. The maximum possible number of filters in a message is 32.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Filter Description List</p></td>
+ <td><p>A description of each filter. A filter description
+ appears in the next table.</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Filter Description</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="2">Filter Identification Value</td>
+ <td colspan="2">Name Length <em>(optional)</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Flags</td>
+ <td colspan="2">Number Client Data Values</td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Name <em>(variable size, optional)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Client Data <em>(variable size,
+ optional)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Filter Identification Value</p></td>
+ <td>
+ <p>
+ This value, often referred to as a filter identifier, is designed
+ to be a unique identifier for the filter. Values from zero through
+ 32,767 are reserved for filters supported by The HDF Group in the
+ HDF5 Library and for filters requested and supported by third
+ parties. Filters supported by The HDF Group are documented
+ immediately below. Information on 3rd-party filters can be found at
+ The HDF Group&rsquo;s <a
+ href="http://www.hdfgroup.org/services/contributions.html">
+ Contributions</a> page.
+ </p>
+
+ <p>
+ To request a filter identifier, please contact The HDF
+ Group&rsquo;s Help Desk at <img src="Graphics/help.png"
+ valign="middle" height="14" alt="The HDF Group Help Desk">.
+ You will be asked to provide the following information:
+ </p>
+ <ol>
+ <li>Contact information for the developer requesting the new
+ identifier</li>
+ <li>A short description of the new filter</li>
+ <li>Links to any relevant information, including licensing
+ information</li>
+ </ol>
+ <p>Values from 32768 to 65535 are reserved for non-distributed
+ uses (for example, internal company usage) or for application usage
+ when testing a feature. The HDF Group does not track or document
+ the use of the filters with identifiers from this range.</p>
+
+ <p>The filters currently in library version 1.8.0 are listed
+ below:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Identification</th>
+ <th width="15%" align="left">Name</th>
+ <th width="65%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>N/A</td>
+ <td>Reserved</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>deflate</td>
+ <td>GZIP deflate compression</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>shuffle</td>
+ <td>Data element shuffling</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>fletcher32</td>
+ <td>Fletcher32 checksum</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>4</code></td>
+ <td>szip</td>
+ <td>SZIP compression</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>5</code></td>
+ <td>nbit</td>
+ <td>N-bit packing</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>6</code></td>
+ <td>scaleoffset</td>
+ <td>Scale and offset encoded values</td>
+ </tr>
+ </table>
+ <p></p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Name Length</p></td>
+ <td><p>Each filter has an optional null-terminated ASCII
+ name and this field holds the length of the name including the null
+ termination padded with nulls to be a multiple of eight. If the
+ filter has no name then a value of zero is stored in this field.</p>
+ <p>
+ Filters with IDs less than 256 (in other words, filters that are
+ defined in this format documentation) do not store the <em>Name
+ Length</em> or <em>Name</em> fields.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Flags</p></td>
+ <td><p>The flags indicate certain properties for a filter.
+ The bit values defined so far are:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>If set then the filter is an optional filter. During
+ output, if an optional filter fails it will be silently skipped
+ in the pipeline.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1-15</code></td>
+ <td>Reserved (zero)</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Number of Client Data Values</p></td>
+ <td><p>
+ Each filter can store integer values to control how the filter
+ operates. The number of entries in the <em>Client Data</em> array
+ is stored in this field.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Name</p></td>
+ <td><p>
+ If the <em>Name Length</em> field is non-zero then it will contain
+ the size of this field, <em>not</em> padded to a multiple of eight.
+ This field contains a <em>non-</em>null-terminated, ASCII character
+ string to serve as a comment/name for the filter.
+ </p>
+ <p>
+ Filters that are defined in this format documentation such as
+ deflate and shuffle do not store the <em>Name Length</em> or <em>Name</em>
+ fields.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Client Data</p></td>
+ <td><p>
+ This is an array of four-byte integers which will be passed to the
+ filter function. The Client Data Number of Values<em></em>
+ determines the number of elements in the array.
+ </p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="AttributeMessage">IV.A.2.m. The Attribute Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Attribute</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x000C</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td><p>The <em>Attribute</em> message is used to store objects
- in the HDF5 file which are used as attributes, or
- &ldquo;metadata&rdquo; about the current object. An attribute
- is a small dataset; it has a name, a datatype, a dataspace, and
- raw data. Since attributes are stored in the object header, they
- should be relatively small (in other words, less than 64KB).
- They can be associated with any type of object which has an
- object header (groups, datasets, or committed (named)
- datatypes).</p>
- <p>In 1.8.x versions of the library, attributes can be larger
- than 64KB. See the
- <a href="UG/HDF5_Users_Guide-Responsive%20HTML5/index.html#t=HDF5_Users_Guide%2FAttributes%2FHDF5_Attributes.htm%3Frhtocid%3Dtoc8.2_1%23TOC_8_5_Special_Issuesbc-13">
- &ldquo;Special Issues&rdquo;</a> section of the Attributes chapter
- in the <cite>HDF5 User&rsquo;s Guide</cite> for more information.</p>
- <p>Note: Attributes on an object must have unique names:
- the HDF5 Library currently enforces this by causing the
- creation of an attribute with a duplicate name to fail.
- Attributes on different objects may have the same name,
- however.</p></td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Attribute Message (Version 1)
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Reserved (zero)</td>
- <td colspan="2">Name Size</td>
- </tr>
-
- <tr>
- <td colspan="2">Datatype Size</td>
- <td colspan="2">Dataspace Size</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Name <em>(variable size)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Datatype <em>(variable size)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Dataspace <em>(variable size)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Data <em>(variable size)</em><br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Attribute</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x000C</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td><p>
+ The <em>Attribute</em> message is used to store objects in the HDF5
+ file which are used as attributes, or &ldquo;metadata&rdquo; about
+ the current object. An attribute is a small dataset; it has a name,
+ a datatype, a dataspace, and raw data. Since attributes are stored
+ in the object header, they should be relatively small (in other
+ words, less than 64KB). They can be associated with any type of
+ object which has an object header (groups, datasets, or committed
+ (named) datatypes).
+ </p>
+ <p>
+ In 1.8.x versions of the library, attributes can be larger than
+ 64KB. See the <a
+ href="UG/HDF5_Users_Guide-Responsive%20HTML5/index.html#t=HDF5_User_Guide%2FAttributes%2FHDF5_Attributes.htm%3Frhtocid%3Dtoc8.2_1%23TOC_8_5_Special_Issuesbc-13">
+ &ldquo;Special Issues&rdquo;</a> section of the Attributes chapter in
+ the <cite>HDF5 User Guide</cite> for more information.
+ </p>
+ <p>Note: Attributes on an object must have unique names: the
+ HDF5 Library currently enforces this by causing the creation of an
+ attribute with a duplicate name to fail. Attributes on different
+ objects may have the same name, however.</p></td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number information is used for changes in the format of the
- attribute message and is described here:
- <table class="list">
- <tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Never used.</td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>Used by the library before version 1.6 to encode attribute message.
- This version does not support shared datatypes.</td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Name Size</p></td>
- <td><p>The length of the attribute name in bytes including the
- null terminator. Note that the <em>Name</em> field below may
- contain additional padding not represented by this
- field.</p></td>
- </tr>
-
- <tr>
- <td><p>Datatype Size</p></td>
- <td><p>The length of the datatype description in the <em>Datatype</em>
- field below. Note that the <em>Datatype</em> field may contain
- additional padding not represented by this field.</p></td>
- </tr>
-
- <tr>
- <td><p>Dataspace Size</p></td>
- <td><p>The length of the dataspace description in the <em>Dataspace</em>
- field below. Note that the <em>Dataspace</em> field may contain
- additional padding not represented by this field.</p></td>
- </tr>
-
- <tr>
- <td><p>Name</p></td>
- <td><p>The null-terminated attribute name. This field is
- padded with additional null characters to make it a
- multiple of eight bytes.</p></td>
- </tr>
-
- <tr>
- <td><p>Datatype</p></td>
- <td><p>The datatype description follows the same format as
- described for the datatype object header message. This
- field is padded with additional zero bytes to make it a
- multiple of eight bytes.</p></td>
- </tr>
-
- <tr>
- <td><p>Dataspace</p></td>
- <td><p>The dataspace description follows the same format as
- described for the dataspace object header message. This
- field is padded with additional zero bytes to make it a
- multiple of eight bytes.</p></td>
- </tr>
-
- <tr>
- <td><p>Data</p></td>
- <td><p>The raw data for the attribute. The size is determined
- from the datatype and dataspace descriptions. This
- field is <em>not</em> padded with additional bytes.</p></td>
- </tr>
- </table>
- </div>
+<div align="center">
+ <table class="format">
+ <caption>Attribute Message (Version 1)</caption>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Attribute Message (Version 2)
- </caption>
-
- <tr align="center">
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Flags</td>
- <td colspan="2">Name Size</td>
- </tr>
-
- <tr>
- <td colspan="2">Datatype Size</td>
- <td colspan="2">Dataspace Size</td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Name <em>(variable size)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Datatype <em>(variable size)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Dataspace <em>(variable size)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Data <em>(variable size)</em><br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number information is used for changes in the
- format of the attribute message and is described here:
+ <tr>
+ <td>Version</td>
+ <td>Reserved (zero)</td>
+ <td colspan="2">Name Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Datatype Size</td>
+ <td colspan="2">Dataspace Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Name <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Datatype <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Dataspace <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Data <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number information is used for changes in
+ the format of the attribute message and is described here:</p>
<table class="list">
- <tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>2</code></td>
- <td>Used by the library of version 1.6.x and after to encode
- attribute messages.
- This version supports shared datatypes. The fields of
- name, datatype, and dataspace are not padded with
- additional bytes of zero.
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Flags</p></td>
- <td><p>This bit field contains extra information about
- interpreting the attribute message:
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>If set, datatype is shared.</td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>If set, dataspace is shared.</td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Name Size</p></td>
- <td><p>The length of the attribute name in bytes including the
- null terminator.</p></td>
- </tr>
-
- <tr>
- <td><p>Datatype Size</p></td>
- <td><p>The length of the datatype description in the <em>Datatype</em>
- field below.</p></td>
- </tr>
-
- <tr>
- <td><p>Dataspace Size</p></td>
- <td><p>The length of the dataspace description in the <em>Dataspace</em>
- field below.</p></td>
- </tr>
-
- <tr>
- <td><p>Name</p></td>
- <td><p>The null-terminated attribute name. This field is <em>not</em>
- padded with additional bytes.</p></td>
- </tr>
-
- <tr>
- <td><p>Datatype</p></td>
- <td><p>The datatype description follows the same format as
- described for the datatype object header message.
- </p>
- <p>If the
- <em>Flag</em> field indicates this attribute&rsquo;s datatype is
- shared, this field will contain a &ldquo;shared message&rdquo; encoding
- instead of the datatype encoding.
- </p>
- <p>This field is <em>not</em> padded with additional bytes.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dataspace</p></td>
- <td><p>The dataspace description follows the same format as
- described for the dataspace object header message.
- </p>
- <p>If the
- <em>Flag</em> field indicates this attribute&rsquo;s dataspace is
- shared, this field will contain a &ldquo;shared message&rdquo; encoding
- instead of the dataspace encoding.
- </p>
- <p>This field is <em>not</em> padded with additional bytes.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Data</p></td>
- <td><p>The raw data for the attribute. The size is determined
- from the datatype and dataspace descriptions.
- </p>
- <p>This field is <em>not</em> padded with additional zero bytes.
- </p>
- </td>
- </tr>
- </table>
- </div>
+ <tr>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
- <br />
- <div align="center">
- <table class="format">
- <caption>
- Attribute Message (Version 3)
- </caption>
-
- <tr align="center">
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Flags</td>
- <td colspan="2">Name Size</td>
- </tr>
-
- <tr>
- <td colspan="2">Datatype Size</td>
- <td colspan="2">Dataspace Size</td>
- </tr>
-
- <tr>
- <td>Name Character Set Encoding</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Name <em>(variable size)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Datatype <em>(variable size)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Dataspace <em>(variable size)</em><br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Data <em>(variable size)</em><br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Never used.</td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number information is used for changes in the
- format of the attribute message and is described here:
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>Used by the library before version 1.6 to encode
+ attribute message. This version does not support shared
+ datatypes.</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Name Size</p></td>
+ <td><p>
+ The length of the attribute name in bytes including the null
+ terminator. Note that the <em>Name</em> field below may contain
+ additional padding not represented by this field.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Datatype Size</p></td>
+ <td><p>
+ The length of the datatype description in the <em>Datatype</em>
+ field below. Note that the <em>Datatype</em> field may contain
+ additional padding not represented by this field.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Dataspace Size</p></td>
+ <td><p>
+ The length of the dataspace description in the <em>Dataspace</em>
+ field below. Note that the <em>Dataspace</em> field may contain
+ additional padding not represented by this field.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Name</p></td>
+ <td><p>The null-terminated attribute name. This field is
+ padded with additional null characters to make it a multiple of
+ eight bytes.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Datatype</p></td>
+ <td><p>The datatype description follows the same format as
+ described for the datatype object header message. This field is
+ padded with additional zero bytes to make it a multiple of eight
+ bytes.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Dataspace</p></td>
+ <td><p>The dataspace description follows the same format as
+ described for the dataspace object header message. This field is
+ padded with additional zero bytes to make it a multiple of eight
+ bytes.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Data</p></td>
+ <td><p>
+ The raw data for the attribute. The size is determined from the
+ datatype and dataspace descriptions. This field is <em>not</em>
+ padded with additional bytes.
+ </p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="format">
+ <caption>Attribute Message (Version 2)</caption>
+
+ <tr align="center">
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td>Flags</td>
+ <td colspan="2">Name Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Datatype Size</td>
+ <td colspan="2">Dataspace Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Name <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Datatype <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Dataspace <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Data <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number information is used for changes in
+ the format of the attribute message and is described here:</p>
<table class="list">
- <tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>3</code></td>
- <td>Used by the library of version 1.8.x and after to
- encode attribute messages.
- This version supports attributes with non-ASCII names.
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Flags</p></td>
- <td><p>This bit field contains extra information about
- interpreting the attribute message:
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>If set, datatype is shared.</td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>If set, dataspace is shared.</td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Name Size</p></td>
- <td><p>The length of the attribute name in bytes including the
- null terminator.</p></td>
- </tr>
-
- <tr>
- <td><p>Datatype Size</p></td>
- <td><p>The length of the datatype description in the <em>Datatype</em>
- field below.</p></td>
- </tr>
-
- <tr>
- <td><p>Dataspace Size</p></td>
- <td><p>The length of the dataspace description in the <em>Dataspace</em>
- field below.</p></td>
- </tr>
-
- <tr>
- <td><p>Name Character Set Encoding</p></td>
- <td><p>The character set encoding for the attribute&rsquo;s name:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>ASCII character set encoding
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>UTF-8 character set encoding
- </td>
- </tr>
- </table>
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Name</p></td>
- <td><p>The null-terminated attribute name. This field is <em>not</em>
- padded with additional bytes.</p></td>
- </tr>
-
- <tr>
- <td><p>Datatype</p></td>
- <td><p>The datatype description follows the same format as
- described for the datatype object header message.
- </p>
- <p>If the
- <em>Flag</em> field indicates this attribute&rsquo;s datatype is
- shared, this field will contain a &ldquo;shared message&rdquo; encoding
- instead of the datatype encoding.
- </p>
- <p>This field is <em>not</em> padded with additional bytes.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Dataspace</p></td>
- <td><p>The dataspace description follows the same format as
- described for the dataspace object header message.
- </p>
- <p>If the
- <em>Flag</em> field indicates this attribute&rsquo;s dataspace is
- shared, this field will contain a &ldquo;shared message&rdquo; encoding
- instead of the dataspace encoding.
- </p>
- <p>This field is <em>not</em> padded with additional bytes.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Data</p></td>
- <td><p>The raw data for the attribute. The size is determined
- from the datatype and dataspace descriptions.
- </p>
- <p>This field is <em>not</em> padded with additional zero bytes.
- </p>
- </td>
- </tr>
- </table>
- </div>
+ <tr>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>Used by the library of version 1.6.x and after to encode
+ attribute messages. This version supports shared datatypes. The
+ fields of name, datatype, and dataspace are not padded with
+ additional bytes of zero.</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Flags</p></td>
+ <td><p>This bit field contains extra information about
+ interpreting the attribute message:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>If set, datatype is shared.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>If set, dataspace is shared.</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Name Size</p></td>
+ <td><p>The length of the attribute name in bytes including
+ the null terminator.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Datatype Size</p></td>
+ <td><p>
+ The length of the datatype description in the <em>Datatype</em>
+ field below.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Dataspace Size</p></td>
+ <td><p>
+ The length of the dataspace description in the <em>Dataspace</em>
+ field below.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Name</p></td>
+ <td><p>
+ The null-terminated attribute name. This field is <em>not</em>
+ padded with additional bytes.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Datatype</p></td>
+ <td><p>The datatype description follows the same format as
+ described for the datatype object header message.</p>
+ <p>
+ If the <em>Flag</em> field indicates this attribute&rsquo;s
+ datatype is shared, this field will contain a &ldquo;shared
+ message&rdquo; encoding instead of the datatype encoding.
+ </p>
+ <p>
+ This field is <em>not</em> padded with additional bytes.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Dataspace</p></td>
+ <td><p>The dataspace description follows the same format as
+ described for the dataspace object header message.</p>
+ <p>
+ If the <em>Flag</em> field indicates this attribute&rsquo;s
+ dataspace is shared, this field will contain a &ldquo;shared
+ message&rdquo; encoding instead of the dataspace encoding.
+ </p>
+ <p>
+ This field is <em>not</em> padded with additional bytes.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Data</p></td>
+ <td><p>The raw data for the attribute. The size is
+ determined from the datatype and dataspace descriptions.</p>
+ <p>
+ This field is <em>not</em> padded with additional zero bytes.
+ </p></td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="CommentMessage">IV.A.2.n. The Object Comment
-Message</a></h4>
+<div align="center">
+ <table class="format">
+ <caption>Attribute Message (Version 3)</caption>
- <!-- start msgdesc table -->
- <center>
+ <tr align="center">
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td>Flags</td>
+ <td colspan="2">Name Size</td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Datatype Size</td>
+ <td colspan="2">Dataspace Size</td>
+ </tr>
+
+ <tr>
+ <td>Name Character Set Encoding</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Name <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Datatype <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Dataspace <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Data <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number information is used for changes in
+ the format of the attribute message and is described here:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>Used by the library of version 1.8.x and after to encode
+ attribute messages. This version supports attributes with
+ non-ASCII names.</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Flags</p></td>
+ <td><p>This bit field contains extra information about
+ interpreting the attribute message:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>If set, datatype is shared.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>If set, dataspace is shared.</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Name Size</p></td>
+ <td><p>The length of the attribute name in bytes including
+ the null terminator.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Datatype Size</p></td>
+ <td><p>
+ The length of the datatype description in the <em>Datatype</em>
+ field below.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Dataspace Size</p></td>
+ <td><p>
+ The length of the dataspace description in the <em>Dataspace</em>
+ field below.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Name Character Set Encoding</p></td>
+ <td><p>The character set encoding for the attribute&rsquo;s
+ name:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>ASCII character set encoding</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>UTF-8 character set encoding</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Name</p></td>
+ <td><p>
+ The null-terminated attribute name. This field is <em>not</em>
+ padded with additional bytes.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Datatype</p></td>
+ <td><p>The datatype description follows the same format as
+ described for the datatype object header message.</p>
+ <p>
+ If the <em>Flag</em> field indicates this attribute&rsquo;s
+ datatype is shared, this field will contain a &ldquo;shared
+ message&rdquo; encoding instead of the datatype encoding.
+ </p>
+ <p>
+ This field is <em>not</em> padded with additional bytes.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Dataspace</p></td>
+ <td><p>The dataspace description follows the same format as
+ described for the dataspace object header message.</p>
+ <p>
+ If the <em>Flag</em> field indicates this attribute&rsquo;s
+ dataspace is shared, this field will contain a &ldquo;shared
+ message&rdquo; encoding instead of the dataspace encoding.
+ </p>
+ <p>
+ This field is <em>not</em> padded with additional bytes.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Data</p></td>
+ <td><p>The raw data for the attribute. The size is
+ determined from the datatype and dataspace descriptions.</p>
+ <p>
+ This field is <em>not</em> padded with additional zero bytes.
+ </p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="CommentMessage">IV.A.2.n. The Object Comment Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Object
- Comment</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x000D</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>The object comment is designed to be a short description of
- an object. An object comment is a sequence of non-zero
- (<code>\0</code>) ASCII characters with no other formatting
- included by the library.</td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Name Message
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td colspan="4"><br />Comment <em>(variable size)</em><br /><br /></td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Object Comment</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x000D</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>The object comment is designed to be a short description of
+ an object. An object comment is a sequence of non-zero (<code>\0</code>)
+ ASCII characters with no other formatting included by the library.
+ </td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Name</p></td>
- <td><p>A null terminated ASCII character string.</p></td>
- </tr>
- </table>
- </div>
+<div align="center">
+ <table class="format">
+ <caption>Name Message</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Comment <em>(variable size)</em><br />
+ <br /></td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="OldModificationTimeMessage">IV.A.2.o. The Object
-Modification Time (Old) Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Name</p></td>
+ <td><p>A null terminated ASCII character string.</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="OldModificationTimeMessage">IV.A.2.o. The Object
+ Modification Time (Old) Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Object
- Modification Time (Old)</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x000E</td></tr>
- <tr><td colspan="2"><b>Length:</b> Fixed</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td><p>The object modification date and time is a timestamp
- which indicates (using ISO-8601 date and time format) the last
- modification of an object. The time is updated when any object
- header message changes according to the system clock where the
- change was posted. All fields of this message should be
- interpreted as coordinated universal time (UTC).</p>
- <p>This modification time message is deprecated in favor of
- the &ldquo;new&rdquo; <a href="#ModificationTimeMessage">Object
- Modification Time</a> message and is no longer written to the
- file in versions of the HDF5 Library after the 1.6.0
- version.</p></td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Modification Time Message
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td colspan="4">Year</td>
- </tr>
-
- <tr>
- <td colspan="2">Month</td>
- <td colspan="2">Day of Month</td>
- </tr>
-
- <tr>
- <td colspan="2">Hour</td>
- <td colspan="2">Minute</td>
- </tr>
-
- <tr>
- <td colspan="2">Second</td>
- <td colspan="2">Reserved</td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Object Modification
+ Time (Old)</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x000E</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Fixed</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td><p>The object modification date and time is a timestamp
+ which indicates (using ISO-8601 date and time format) the last
+ modification of an object. The time is updated when any object
+ header message changes according to the system clock where the
+ change was posted. All fields of this message should be interpreted
+ as coordinated universal time (UTC).</p>
+ <p>
+ This modification time message is deprecated in favor of the
+ &ldquo;new&rdquo; <a href="#ModificationTimeMessage">Object
+ Modification Time</a> message and is no longer written to the file in
+ versions of the HDF5 Library after the 1.6.0 version.
+ </p></td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Year</p></td>
- <td><p>The four-digit year as an ASCII string. For example,
- <code>1998</code>.
- </p></td>
- </tr>
-
- <tr>
- <td><p>Month</p></td>
- <td><p>The month number as a two digit ASCII string where
- January is <code>01</code> and December is <code>12</code>.</p></td>
- </tr>
-
- <tr>
- <td><p>Day of Month</p></td>
- <td><p>The day number within the month as a two digit ASCII
- string. The first day of the month is <code>01</code>.</p></td>
- </tr>
-
- <tr>
- <td><p>Hour</p></td>
- <td><p>The hour of the day as a two digit ASCII string where
- midnight is <code>00</code> and 11:00pm is <code>23</code>.</p></td>
- </tr>
-
- <tr>
- <td><p>Minute</p></td>
- <td><p>The minute of the hour as a two digit ASCII string where
- the first minute of the hour is <code>00</code> and
- the last is <code>59</code>.</p></td>
- </tr>
-
- <tr>
- <td><p>Second</p></td>
- <td><p>The second of the minute as a two digit ASCII string
- where the first second of the minute is <code>00</code>
- and the last is <code>59</code>.</p></td>
- </tr>
-
- <tr>
- <td><p>Reserved</p></td>
- <td><p>This field is reserved and should always be zero.</p></td>
- </tr>
- </table>
- </div>
+<div align="center">
+ <table class="format">
+ <caption>Modification Time Message</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="4">Year</td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Month</td>
+ <td colspan="2">Day of Month</td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Hour</td>
+ <td colspan="2">Minute</td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Second</td>
+ <td colspan="2">Reserved</td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="SOHMTableMessage">IV.A.2.p. The Shared Message Table
-Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Year</p></td>
+ <td><p>
+ The four-digit year as an ASCII string. For example,
+ <code>1998</code>
+ .
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Month</p></td>
+ <td><p>
+ The month number as a two digit ASCII string where January is
+ <code>01</code>
+ and December is
+ <code>12</code>
+ .
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Day of Month</p></td>
+ <td><p>
+ The day number within the month as a two digit ASCII string. The
+ first day of the month is
+ <code>01</code>
+ .
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Hour</p></td>
+ <td><p>
+ The hour of the day as a two digit ASCII string where midnight is
+ <code>00</code>
+ and 11:00pm is
+ <code>23</code>
+ .
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Minute</p></td>
+ <td><p>
+ The minute of the hour as a two digit ASCII string where the first
+ minute of the hour is
+ <code>00</code>
+ and the last is
+ <code>59</code>
+ .
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Second</p></td>
+ <td><p>
+ The second of the minute as a two digit ASCII string where the
+ first second of the minute is
+ <code>00</code>
+ and the last is
+ <code>59</code>
+ .
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Reserved</p></td>
+ <td><p>This field is reserved and should always be zero.</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="SOHMTableMessage">IV.A.2.p. The Shared Message Table
+ Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Shared Message
- Table</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x000F</td></tr>
- <tr><td colspan="2"><b>Length:</b> Fixed</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>This message is used to locate the table of shared object
- header message (SOHM) indexes. Each index consists of information
- to find the shared messages from either the heap or object header.
- This message is <em>only</em> found in the superblock
- extension.</td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Shared Message Table Message
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Shared Object Header Message Table Address<sup>O</sup><br /><br /></td>
- </tr>
-
- <tr>
- <td>Number of Indices</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Shared Message Table</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x000F</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Fixed</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>This message is used to locate the table of shared object
+ header message (SOHM) indexes. Each index consists of information to
+ find the shared messages from either the heap or object header. This
+ message is <em>only</em> found in the superblock extension.
+ </td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- </table>
+<div align="center">
+ <table class="format">
+ <caption>Shared Message Table Message</caption>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
- </div>
+ <tr>
+ <td>Version</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number for this message. This document describes version 0.</p></td>
- </tr>
-
- <tr>
- <td><p>Shared Object Header Message Table Address</p></td>
- <td><p>This field is the address of the master table for shared
- object header message indexes.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Number of Indices</p></td>
- <td><p>This field is the number of indices in the master table.
- </p></td>
- </tr>
+ <tr>
+ <td colspan="4"><br />Shared Object Header Message Table
+ Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td>Number of Indices</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
+
+</div>
<br />
-<h4><a name="ContinuationMessage">IV.A.2.q. The Object Header
-Continuation Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number for this message. This document
+ describes version 0.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Shared Object Header Message Table Address</p></td>
+ <td><p>This field is the address of the master table for
+ shared object header message indexes.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Number of Indices</p></td>
+ <td><p>This field is the number of indices in the master
+ table.</p></td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="ContinuationMessage">IV.A.2.q. The Object Header
+ Continuation Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Object Header
- Continuation</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0010</td></tr>
- <tr><td colspan="2"><b>Length:</b> Fixed</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>The object header continuation is the location in the file
- of a block containing more header messages for the current data
- object. This can be used when header blocks become too large or
- are likely to change over time.</td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Object Header Continuation Message
- </caption>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Object Header
+ Continuation</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0010</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Fixed</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>The object header continuation is the location in the file
+ of a block containing more header messages for the current data
+ object. This can be used when header blocks become too large or are
+ likely to change over time.</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
+
+<div align="center">
+ <table class="format">
+ <caption>Object Header Continuation Message</caption>
<tr>
- <th width=25%>byte</th>
- <th width=25%>byte</th>
- <th width=25%>byte</th>
- <th width=25%>byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
</tr>
<tr>
- <td colspan="4"><br />Offset<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Offset<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Length<sup>L</sup><br /><br /></td>
+ <td colspan="4"><br />Length<sup>L</sup><br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>Offset</p></td>
- <td><p>This value is the address in the file where the
- header continuation block is located.</p></td>
+ <td><p>Offset</p></td>
+ <td><p>This value is the address in the file where the
+ header continuation block is located.</p></td>
</tr>
<tr>
- <td><p>Length</p></td>
- <td><p>This value is the length in bytes of the header continuation
- block in the file.</p></td>
+ <td><p>Length</p></td>
+ <td><p>This value is the length in bytes of the header
+ continuation block in the file.</p></td>
</tr>
- </table>
- </div>
- <br />
+ </table>
+</div>
+<br />
- <p>The format of the header continuation block that this message points
- to depends on the version of the object header that the message is
- contained within.
- </p>
-
- <p>
- Continuation blocks for version 1 object headers have no special
- formatting information; they are merely a list of object header
- message info sequences (type, size, flags, reserved bytes and data
- for each message sequence). See the description
- of <a href="#V1ObjectHeaderPrefix">Version 1 Data Object Header Prefix.</a>
- </p>
-
- <p>Continuation blocks for version 2 object headers <em>do</em> have
- special formatting information as described here
- (see also the description of
- <a href="#V2ObjectHeaderPrefix">Version 2 Data Object Header Prefix.</a>):
- </p>
- <div align="center">
- <table class="format">
- <caption>
- Version 2 Object Header Continuation Block
- </caption>
-
- <tr>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- <th>byte</th>
- </tr>
-
- <tr>
- <td colspan="4">Signature</td>
- </tr>
- <tr>
- <td>Header Message Type #1</td>
- <td colspan="2">Size of Header Message Data #1</td>
- <td>Header Message #1 Flags</td>
- </tr>
-
- <tr>
- <td colspan="2">Header Message #1 Creation Order <em>(optional)</em></td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Header Message Data #1<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4">.<br />.<br />.<br /></td>
- </tr>
-
- <tr>
- <td>Header Message Type #n</td>
- <td colspan="2">Size of Header Message Data #n</td>
- <td>Header Message #n Flags</td>
- </tr>
-
- <tr>
- <td colspan="2">Header Message #n Creation Order <em>(optional)</em></td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br />Header Message Data #n<br /><br /></td>
- </tr>
-
- <tr>
- <td colspan="4">Gap <em>(optional, variable size)</em></td>
- </tr>
-
- <tr>
- <td colspan="4">Checksum</td>
- </tr>
- </table>
- </div>
+<p>The format of the header continuation block that this message
+ points to depends on the version of the object header that the message
+ is contained within.</p>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Signature</p></td>
- <td>
- <p>The ASCII character string &ldquo;<code>OCHK</code>&rdquo;
- is used to indicate the
- beginning of an object header continuation block. This gives file
- consistency checking utilities a better chance of reconstructing a
- damaged file.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Header Message #n Type</p></td>
- <td>
- <p>Same format as version 1 of the object header, described above.
- </p></td>
- </tr>
-
- <tr>
- <td><p>Size of Header Message #n Data</p></td>
- <td>
- <p>Same format as version 1 of the object header, described above.
- </p></td>
- </tr>
-
- <tr>
- <td><p>Header Message #n Flags</p></td>
- <td>
- <p>Same format as version 1 of the object header, described above.
- </p></td>
- </tr>
-
- <tr>
- <td><p>Header Message #n Creation Order</p></td>
- <td>
- <p>This field stores the order that a message of a given type
- was created in.</p>
- <p>This field is present if bit 2 of <em>flags</em> is set.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Header Message #n Data</p></td>
- <td>
- <p>Same format as version 1 of the object header, described above.
- </p></td>
- </tr>
-
- <tr>
- <td><p>Gap</p></td>
- <td>
- <p>A gap in an object header chunk is inferred by the end of the
- messages for the chunk before the beginning of the chunk&rsquo;s
- checksum. Gaps are always smaller than the size of an
- object header message prefix (message type + message size +
- message flags).</p>
- <p>Gaps are formed when a message (typically an attribute message)
- in an earlier chunk is deleted and a message from a later
- chunk that does not quite fit into the free space is moved
- into the earlier chunk.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Checksum</p></td>
- <td>
- <p>This is the checksum for the object header chunk.
- </p>
- </td>
+<p>
+ Continuation blocks for version 1 object headers have no special
+ formatting information; they are merely a list of object header message
+ info sequences (type, size, flags, reserved bytes and data for each
+ message sequence). See the description of <a
+ href="#V1ObjectHeaderPrefix">Version 1 Data Object Header Prefix.</a>
+</p>
+
+<p>
+ Continuation blocks for version 2 object headers <em>do</em> have
+ special formatting information as described here (see also the
+ description of <a href="#V2ObjectHeaderPrefix">Version 2 Data
+ Object Header Prefix.</a>):
+</p>
+<div align="center">
+ <table class="format">
+ <caption>Version 2 Object Header Continuation Block</caption>
+
+ <tr>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ <th>byte</th>
+ </tr>
+
+ <tr>
+ <td colspan="4">Signature</td>
+ </tr>
+ <tr>
+ <td>Header Message Type #1</td>
+ <td colspan="2">Size of Header Message Data #1</td>
+ <td>Header Message #1 Flags</td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Header Message #1 Creation Order <em>(optional)</em></td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Header Message Data #1<br />
+ <br /></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">.<br />.<br />.<br /></td>
+ </tr>
+
+ <tr>
+ <td>Header Message Type #n</td>
+ <td colspan="2">Size of Header Message Data #n</td>
+ <td>Header Message #n Flags</td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Header Message #n Creation Order <em>(optional)</em></td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />Header Message Data #n<br />
+ <br /></td>
</tr>
- </table>
- </div>
+
+ <tr>
+ <td colspan="4">Gap <em>(optional, variable size)</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Checksum</td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="SymbolTableMessage">IV.A.2.r. The Symbol Table
-Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Signature</p></td>
+ <td>
+ <p>
+ The ASCII character string &ldquo;
+ <code>OCHK</code>
+ &rdquo; is used to indicate the beginning of an object header
+ continuation block. This gives file consistency checking utilities
+ a better chance of reconstructing a damaged file.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Header Message #n Type</p></td>
+ <td>
+ <p>Same format as version 1 of the object header, described
+ above.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Size of Header Message #n Data</p></td>
+ <td>
+ <p>Same format as version 1 of the object header, described
+ above.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Header Message #n Flags</p></td>
+ <td>
+ <p>Same format as version 1 of the object header, described
+ above.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Header Message #n Creation Order</p></td>
+ <td>
+ <p>This field stores the order that a message of a given type
+ was created in.</p>
+ <p>
+ This field is present if bit 2 of <em>flags</em> is set.
+ </p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Header Message #n Data</p></td>
+ <td>
+ <p>Same format as version 1 of the object header, described
+ above.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Gap</p></td>
+ <td>
+ <p>A gap in an object header chunk is inferred by the end of the
+ messages for the chunk before the beginning of the chunk&rsquo;s
+ checksum. Gaps are always smaller than the size of an object header
+ message prefix (message type + message size + message flags).</p>
+ <p>Gaps are formed when a message (typically an attribute
+ message) in an earlier chunk is deleted and a message from a later
+ chunk that does not quite fit into the free space is moved into the
+ earlier chunk.</p>
+ </td>
+ </tr>
+
+ <tr>
+ <td><p>Checksum</p></td>
+ <td>
+ <p>This is the checksum for the object header chunk.</p>
+ </td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="SymbolTableMessage">IV.A.2.r. The Symbol Table Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Symbol Table
- Message</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0011</td></tr>
- <tr><td colspan="2"><b>Length:</b> Fixed</td></tr>
- <tr><td colspan="2"><b>Status:</b> Required for
- &ldquo;old style&rdquo; groups; may not be repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>Each &ldquo;old style&rdquo; group has a v1 B-tree and a
- local heap for storing symbol table entries, which are located
- with this message.</td></tr>
- <tr><td colspan="2"><b>Format of data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Symbol Table Message</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0011</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Fixed</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Required for &ldquo;old
+ style&rdquo; groups; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>Each &ldquo;old style&rdquo; group has a v1 B-tree and a
+ local heap for storing symbol table entries, which are located with
+ this message.</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
+
+<div align="center">
+ <table class="format">
<caption>
- <b>Symbol Table Message</b>
+ <b>Symbol Table Message</b>
</caption>
<tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
</tr>
<tr>
- <td colspan="4"><br />v1 B-tree Address<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />v1 B-tree Address<sup>O</sup><br />
+ <br /></td>
</tr>
<tr>
- <td colspan="4"><br />Local Heap Address<sup>O</sup><br /><br /></td>
+ <td colspan="4"><br />Local Heap Address<sup>O</sup><br />
+ <br /></td>
</tr>
- </table>
+ </table>
- <table class="note">
+ <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
+<br />
+<div align="center">
+ <table class="desc">
<tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
</tr>
<tr>
- <td><p>v1 B-tree Address</p></td>
- <td><p>This value is the address of the v1 B-tree containing the
- symbol table entries for the group.</p></td>
+ <td><p>v1 B-tree Address</p></td>
+ <td><p>This value is the address of the v1 B-tree containing
+ the symbol table entries for the group.</p></td>
</tr>
<tr>
- <td><p>Local Heap Address</p></td>
- <td><p>This value is the address of the local heap containing
- the link names for the symbol table entries for the group.</p></td>
+ <td><p>Local Heap Address</p></td>
+ <td><p>This value is the address of the local heap
+ containing the link names for the symbol table entries for the
+ group.</p></td>
</tr>
- </table>
- </div>
+ </table>
+</div>
<br />
-<h4><a name="ModificationTimeMessage">IV.A.2.s. The Object
-Modification Time Message</a></h4>
+<h4>
+ <a name="ModificationTimeMessage">IV.A.2.s. The Object Modification
+ Time Message</a>
+</h4>
- <!-- start msgdesc table -->
- <center>
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Object
- Modification Time</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0012</td></tr>
- <tr><td colspan="2"><b>Length:</b> Fixed</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>The object modification time is a timestamp which indicates
- the time of the last modification of an object. The time is
- updated when any object header message changes according to
- the system clock where the change was posted.</td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Modification Time Message
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td colspan="3">Reserved (zero)</td>
- </tr>
-
- <tr>
- <td colspan="4">Seconds After UNIX Epoch</td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Object Modification
+ Time</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0012</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Fixed</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>The object modification time is a timestamp which indicates
+ the time of the last modification of an object. The time is updated
+ when any object header message changes according to the system clock
+ where the change was posted.</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number is used for changes in the format of Object Modification Time
- and is described here:
- <table class="list">
- <tr>
- <th width="20%" align="center">Version</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>Never used.</td>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>Used by Version 1.6.1 and after of the library to encode time. In
- this version, the time is the seconds after Epoch.</td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Seconds After UNIX Epoch</p></td>
- <td><p>A 32-bit unsigned integer value that stores the number of
- seconds since 0 hours, 0 minutes, 0 seconds, January 1, 1970,
- Coordinated Universal Time.</p></td>
- </tr>
- </table>
- </div>
+<div align="center">
+ <table class="format">
+ <caption>Modification Time Message</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td colspan="3">Reserved (zero)</td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Seconds After UNIX Epoch</td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="BtreeKValuesMessage">IV.A.2.t. The B-tree
-&lsquo;K&rsquo; Values Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number is used for changes in the format
+ of Object Modification Time and is described here:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Version</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>Never used.</td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>Used by Version 1.6.1 and after of the library to encode
+ time. In this version, the time is the seconds after Epoch.</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Seconds After UNIX Epoch</p></td>
+ <td><p>A 32-bit unsigned integer value that stores the
+ number of seconds since 0 hours, 0 minutes, 0 seconds, January 1,
+ 1970, Coordinated Universal Time.</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="BtreeKValuesMessage">IV.A.2.t. The B-tree &lsquo;K&rsquo;
+ Values Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> B-tree
- &lsquo;K&rsquo; Values</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0013</td></tr>
- <tr><td colspan="2"><b>Length:</b> Fixed</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>This message retrieves non-default &lsquo;K&rsquo; values
- for internal and leaf nodes of a group or indexed storage v1
- B-trees. This message is <em>only</em> found in the superblock
- extension.</td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- B-tree &lsquo;K&rsquo; Values Message
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td colspan="2">Indexed Storage Internal Node K</td>
- <td bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="2">Group Internal Node K</td>
- <td colspan="2">Group Leaf Node K</td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> B-tree
+ &lsquo;K&rsquo; Values</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0013</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Fixed</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>This message retrieves non-default &lsquo;K&rsquo; values
+ for internal and leaf nodes of a group or indexed storage v1
+ B-trees. This message is <em>only</em> found in the superblock
+ extension.
+ </td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number for this message. This document describes
- version 0.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Indexed Storage Internal Node K</p></td>
- <td><p>This is the node &lsquo;K&rsquo; value for each internal node of an
- indexed storage v1 B-tree. See the description of this field
- in version 0 and 1 of the superblock as well the section on
- v1 B-trees.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Group Internal Node K</p></td>
- <td><p>This is the node &lsquo;K&rsquo; value for each internal node of a group
- v1 B-tree. See the description of this field in version 0 and
- 1 of the superblock as well as the section on v1 B-trees.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Group Leaf Node K</p></td>
- <td><p>This is the node &lsquo;K&rsquo; value for each leaf node of a group v1
- B-tree. See the description of this field in version 0 and 1
- of the superblock as well as the section on v1 B-trees.
- </p>
- </td>
- </tr>
+<div align="center">
+ <table class="format">
+ <caption>B-tree &lsquo;K&rsquo; Values Message</caption>
- </table>
- </div>
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td colspan="2">Indexed Storage Internal Node K</td>
+ <td bgcolor="#DDDDDD"><em>This space inserted only to align
+ table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Group Internal Node K</td>
+ <td colspan="2">Group Leaf Node K</td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="DrvInfoMessage">IV.A.2.u. The Driver Info
-Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number for this message. This document
+ describes version 0.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Indexed Storage Internal Node K</p></td>
+ <td><p>This is the node &lsquo;K&rsquo; value for each
+ internal node of an indexed storage v1 B-tree. See the description
+ of this field in version 0 and 1 of the superblock as well the
+ section on v1 B-trees.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Group Internal Node K</p></td>
+ <td><p>This is the node &lsquo;K&rsquo; value for each
+ internal node of a group v1 B-tree. See the description of this
+ field in version 0 and 1 of the superblock as well as the section
+ on v1 B-trees.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Group Leaf Node K</p></td>
+ <td><p>This is the node &lsquo;K&rsquo; value for each leaf
+ node of a group v1 B-tree. See the description of this field in
+ version 0 and 1 of the superblock as well as the section on v1
+ B-trees.</p></td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="DrvInfoMessage">IV.A.2.u. The Driver Info Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Driver
- Info</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0014</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
-
- <tr><td>
- <b>Description:</b></td>
- <td>This message contains information needed by the file driver
- to reopen a file. This message is <em>only</em> found in the
- superblock extension: see the <a href="#SuperblockExt">
- &ldquo;Disk Format: Level 0C - Superblock Extension&rdquo;</a>
- section for more information. For more information on the fields
- in the driver info message, see the <a href="#DriverInfo">
- &ldquo;Disk Format : Level 0B - File Driver Info&rdquo;</a>
- section; those who use the multi and family file drivers will
- find this section particularly helpful.</td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Driver Info Message
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
- <tr>
- <td colspan="4"><br />Driver Identification</td>
- </tr>
-
- <tr>
- <td colspan="2">Driver Information Size</td>
- <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4"><br /><br />Driver Information <em>(variable size)</em><br /><br /><br /></td>
- </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Driver Info</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0014</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
- </table>
- </div>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>This message contains information needed by the file driver
+ to reopen a file. This message is <em>only</em> found in the
+ superblock extension: see the <a href="#SuperblockExt">
+ &ldquo;Disk Format: Level 0C - Superblock Extension&rdquo;</a> section
+ for more information. For more information on the fields in the
+ driver info message, see the <a href="#DriverInfo"> &ldquo;Disk
+ Format : Level 0B - File Driver Info&rdquo;</a> section; those who use
+ the multi and family file drivers will find this section
+ particularly helpful.
+ </td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number for this message. This document describes
- version 0.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Driver Identification</p></td>
- <td><p>This is an eight-byte ASCII string without null termination which
- identifies the driver.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Driver Information Size</p></td>
- <td><p>The size in bytes of the <em>Driver Information</em> field of this
- message.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Driver Information</p></td>
- <td><p>Driver information is stored in a format defined by the file driver.</p>
- </td>
- </tr>
- </table>
- </div>
+<div align="center">
+ <table class="format">
+ <caption>Driver Info Message</caption>
+
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Driver Identification</td>
+ </tr>
+
+ <tr>
+ <td colspan="2">Driver Information Size</td>
+ <td colspan="2" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4"><br />
+ <br />Driver Information <em>(variable size)</em><br />
+ <br />
+ <br /></td>
+ </tr>
+
+ </table>
+</div>
<br />
-<h4><a name="AinfoMessage">IV.A.2.v. The Attribute Info
-Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number for this message. This document
+ describes version 0.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Driver Identification</p></td>
+ <td><p>This is an eight-byte ASCII string without null
+ termination which identifies the driver.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Driver Information Size</p></td>
+ <td><p>
+ The size in bytes of the <em>Driver Information</em> field of this
+ message.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Driver Information</p></td>
+ <td><p>Driver information is stored in a format defined by
+ the file driver.</p></td>
+ </tr>
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="AinfoMessage">IV.A.2.v. The Attribute Info Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Attribute
- Info</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0015</td></tr>
- <tr><td colspan="2"><b>Length:</b> Varies</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>This message stores information about the attributes on an
- object, such as the maximum creation index for the attributes
- created and the location of the attribute storage when the
- attributes are stored &ldquo;densely&rdquo;.</td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Attribute Info Message
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Flags</td>
- <td colspan="2">Maximum Creation Index <em>(optional)</em></td>
- </tr>
- <tr>
- <td colspan="4"><br />Fractal Heap Address<sup>O</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Attribute Name v2 B-tree Address<sup>O</sup><br /><br /></td>
- </tr>
- <tr>
- <td colspan="4"><br />Attribute Creation Order v2 B-tree Address<sup>O</sup> <em>(optional)</em><br /><br /></td>
- </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Attribute Info</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0015</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Varies</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>This message stores information about the attributes on an
+ object, such as the maximum creation index for the attributes
+ created and the location of the attribute storage when the
+ attributes are stored &ldquo;densely&rdquo;.</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- </table>
+<div align="center">
+ <table class="format">
+ <caption>Attribute Info Message</caption>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td>Flags</td>
+ <td colspan="2">Maximum Creation Index <em>(optional)</em></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Fractal Heap Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Attribute Name v2 B-tree Address<sup>O</sup><br />
+ <br /></td>
+ </tr>
+ <tr>
+ <td colspan="4"><br />Attribute Creation Order v2 B-tree
+ Address<sup>O</sup> <em>(optional)</em><br />
+ <br /></td>
+ </tr>
- </div>
+ </table>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number for this message. This document describes
- version 0.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Flags</p></td>
- <td><p>This is the attribute index information flag with the
- following definition:
-
- <table class="list">
- <tr>
- <th width="20%" align="center">Bit</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>0</code></td>
- <td>If set, creation order for attributes is tracked.
- </td>
- </tr>
- <tr>
- <td align="center"><code>1</code></td>
- <td>If set, creation order for attributes is indexed.
- </td>
- </tr>
- <tr>
- <td align="center"><code>2-7</code></td>
- <td>Reserved</td>
- </tr>
- </table></p>
-
- </td>
- </tr>
-
- <tr>
- <td><p>Maximum Creation Index</p></td>
- <td><p>The is the maximum creation order index value for the
- attributes on the object.</p>
- <p>This field is present if bit 0 of <em>Flags</em> is set.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Fractal Heap Address</p></td>
- <td><p>This is the address of the fractal heap to store dense
- attributes.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Attribute Name v2 B-tree Address</p></td>
- <td><p>This is the address of the version 2 B-tree to index the
- names of densely stored attributes.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Attribute Creation Order v2 B-tree Address</p></td>
- <td><p>This is the address of the version 2 B-tree to index the
- creation order of densely stored attributes.</p>
- <p>This field is present if bit 1 of <em>Flags</em> is set.</p>
- </td>
- </tr>
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ </table>
- </table>
- </div>
+</div>
<br />
-<h4><a name="RefCountMessage">IV.A.2.w. The Object Reference
-Count Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number for this message. This document
+ describes version 0.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Flags</p></td>
+ <td><p>This is the attribute index information flag with the
+ following definition:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Bit</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>0</code></td>
+ <td>If set, creation order for attributes is tracked.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>If set, creation order for attributes is indexed.</td>
+ </tr>
+ <tr>
+ <td align="center"><code>2-7</code></td>
+ <td>Reserved</td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Maximum Creation Index</p></td>
+ <td><p>The is the maximum creation order index value for the
+ attributes on the object.</p>
+ <p>
+ This field is present if bit 0 of <em>Flags</em> is set.
+ </p></td>
+ </tr>
+
+ <tr>
+ <td><p>Fractal Heap Address</p></td>
+ <td><p>This is the address of the fractal heap to store
+ dense attributes.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Attribute Name v2 B-tree Address</p></td>
+ <td><p>This is the address of the version 2 B-tree to index
+ the names of densely stored attributes.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Attribute Creation Order v2 B-tree Address</p></td>
+ <td><p>This is the address of the version 2 B-tree to index
+ the creation order of densely stored attributes.</p>
+ <p>
+ This field is present if bit 1 of <em>Flags</em> is set.
+ </p></td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="RefCountMessage">IV.A.2.w. The Object Reference Count
+ Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> Object Reference
- Count</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0016</td></tr>
- <tr><td colspan="2"><b>Length:</b> Fixed</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
- <tr><td><b>Description:</b></td>
- <td>This message stores the number of hard links (in groups or
- objects) pointing to an object: in other words, its
- <em>reference count</em>.</td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- Object Reference Count
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted only to align table nicely</em></td>
- </tr>
-
- <tr>
- <td colspan="4">Reference count</td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> Object Reference
+ Count</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0016</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Fixed</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>This message stores the number of hard links (in groups or
+ objects) pointing to an object: in other words, its <em>reference
+ count</em>.
+ </td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>The version number for this message. This document describes
- version 0.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Reference Count</p></td>
- <td><p>The unsigned 32-bit integer is the reference count for the
- object. This message is only present in &ldquo;version 2&rdquo;
- (or later) object headers, and if not present those object
- header versions, the reference count for the object is assumed
- to be 1.</p>
- </td>
- </tr>
+<div align="center">
+ <table class="format">
+ <caption>Object Reference Count</caption>
- </table>
- </div>
+ <tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
+ <tr>
+ <td>Version</td>
+ <td colspan="3" bgcolor="#DDDDDD"><em>This space inserted
+ only to align table nicely</em></td>
+ </tr>
+
+ <tr>
+ <td colspan="4">Reference count</td>
+ </tr>
+ </table>
+</div>
<br />
-<h4><a name="FsinfoMessage">IV.A.2.x. The File Space Info
-Message</a></h4>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
- <!-- start msgdesc table -->
- <center>
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>The version number for this message. This document
+ describes version 0.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Reference Count</p></td>
+ <td><p>The unsigned 32-bit integer is the reference count
+ for the object. This message is only present in &ldquo;version
+ 2&rdquo; (or later) object headers, and if not present those object
+ header versions, the reference count for the object is assumed to
+ be 1.</p></td>
+ </tr>
+
+ </table>
+</div>
+
+<br />
+<h4>
+ <a name="FsinfoMessage">IV.A.2.x. The File Space Info Message</a>
+</h4>
+
+<!-- start msgdesc table -->
+<center>
<table class="msgdesc">
- <tr><td colspan="2"><b>Header Message Name:</b> File Space
- Info</td></tr>
- <tr><td colspan="2"><b>Header Message Type:</b> 0x0018</td></tr>
- <tr><td colspan="2"><b>Length:</b> Fixed</td></tr>
- <tr><td colspan="2"><b>Status:</b> Optional; may not be
- repeated.</td></tr>
- <tr><td>
- <b>Description:</b></td>
- <td>This message stores the file space management strategy (see
- description below) that the library uses in handling file space
- request for the file. It also contains the free-space section
- threshold used by the library&rsquo;s free-space managers for
- the file. If the strategy is 1, this message also contains the
- addresses of the file&rsquo;s free-space managers which track
- free space for each type of file space allocation. There are
- six basic types of file space allocation: superblock, B-tree,
- raw data, global heap, local heap, and object header. See the
- description of <a href="#FreeSpaceManager">Free-space
- Manager</a> as well the description of allocation types in
- <a href="#AppendixB">Appendix B</a>.</td></tr>
- <tr><td colspan="2"><b>Format of Data:</b> See the tables
- below.</td></tr>
- </table></center>
- <!-- end msgdesc table -->
-
- <div align="center">
- <table class="format">
- <caption>
- File Space Info
- </caption>
-
- <tr>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- <th width="25%">byte</th>
- </tr>
-
- <tr>
- <td>Version</td>
- <td>Strategy</td>
- <td colspan="2">Threshold<sup>L</sup></td>
- </tr>
- <tr>
- <td colspan="4">Super-block Free-space Manager Address<sup>O</sup></td>
- </tr>
- <tr>
- <td colspan="4">B-tree Free-space Manager Address<sup>O</sup></td>
- </tr>
- <tr>
- <td colspan="4">Raw Data Free-space Manager Address<sup>O</sup></td>
- </tr>
- <tr>
- <td colspan="4">Global Heap Free-space Manager Address<sup>O</sup></td>
- </tr>
- <tr>
- <td colspan="4">Local Heap Free-space Manager Address<sup>O</sup></td>
- </tr>
- <tr>
- <td colspan="4">Object Header Free-space Manager Address<sup>O</sup></td>
- </tr>
- </table>
+ <tr>
+ <td colspan="2"><b>Header Message Name:</b> File Space Info</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Header Message Type:</b> 0x0018</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Length:</b> Fixed</td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Status:</b> Optional; may not be repeated.</td>
+ </tr>
+ <tr>
+ <td><b>Description:</b></td>
+ <td>This message stores the file space management strategy (see
+ description below) that the library uses in handling file space
+ request for the file. It also contains the free-space section
+ threshold used by the library&rsquo;s free-space managers for the
+ file. If the strategy is 1, this message also contains the addresses
+ of the file&rsquo;s free-space managers which track free space for
+ each type of file space allocation. There are six basic types of
+ file space allocation: superblock, B-tree, raw data, global heap,
+ local heap, and object header. See the description of <a
+ href="#FreeSpaceManager">Free-space Manager</a> as well the
+ description of allocation types in <a href="#AppendixB">Appendix
+ B</a>.
+ </td>
+ </tr>
+ <tr>
+ <td colspan="2"><b>Format of Data:</b> See the tables below.</td>
+ </tr>
+ </table>
+</center>
+<!-- end msgdesc table -->
+
+<div align="center">
+ <table class="format">
+ <caption>File Space Info</caption>
- <table class="note">
<tr>
- <td width="60%">&nbsp;</td>
- <td width="40%">
- (Items marked with an &lsquo;O&rsquo; in the above table are of the size
- specified in &ldquo;Size of Offsets&rdquo; field in the superblock.)
- </td></tr>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ <th width="25%">byte</th>
+ </tr>
+
<tr>
- <td>&nbsp;</td>
- <td>
- (Items marked with an &lsquo;L&rsquo; in the above table are of the size
- specified in &ldquo;Size of Lengths&rdquo; field in the superblock.)
- </td></tr>
- </table>
+ <td>Version</td>
+ <td>Strategy</td>
+ <td colspan="2">Threshold<sup>L</sup></td>
+ </tr>
+ <tr>
+ <td colspan="4">Super-block Free-space Manager Address<sup>O</sup></td>
+ </tr>
+ <tr>
+ <td colspan="4">B-tree Free-space Manager Address<sup>O</sup></td>
+ </tr>
+ <tr>
+ <td colspan="4">Raw Data Free-space Manager Address<sup>O</sup></td>
+ </tr>
+ <tr>
+ <td colspan="4">Global Heap Free-space Manager Address<sup>O</sup></td>
+ </tr>
+ <tr>
+ <td colspan="4">Local Heap Free-space Manager Address<sup>O</sup></td>
+ </tr>
+ <tr>
+ <td colspan="4">Object Header Free-space Manager Address<sup>O</sup></td>
+ </tr>
+ </table>
+
+ <table class="note">
+ <tr>
+ <td width="60%">&nbsp;</td>
+ <td width="40%">(Items marked with an &lsquo;O&rsquo; in the
+ above table are of the size specified in &ldquo;Size of
+ Offsets&rdquo; field in the superblock.)</td>
+ </tr>
+ <tr>
+ <td>&nbsp;</td>
+ <td>(Items marked with an &lsquo;L&rsquo; in the above table are
+ of the size specified in &ldquo;Size of Lengths&rdquo; field in the
+ superblock.)</td>
+ </tr>
+ </table>
- </div>
+</div>
- <br />
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Field Name</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td><p>Version</p></td>
- <td><p>This is the version number of this message. This document describes
- version 0.</p>
- </td>
- </tr>
-
- <tr>
- <td><p>Strategy</p></td>
- <td><p>This is the file space management strategy for the file.
- There are four types of strategies:
- <table class="list">
- <tr>
- <th width="20%" align="center">Value</th>
- <th width="80%" align="left">Description</th>
- </tr>
-
- <tr>
- <td align="center"><code>1</code></td>
- <td>With this strategy, the HDF5 Library&rsquo;s free-space managers track the
- free space that results from the manipulation of HDF5 objects
- in the HDF5 file. The free space information is saved when the
- file is closed, and reloaded when the file is reopened.
- <br />
- When space is needed for file metadata or raw data,
- the HDF5 Library first requests space from the library&rsquo;s free-space
- managers. If the request is not satisfied, the library requests space
- from the aggregators. If the request is still not satisfied,
- the library requests space from the virtual file driver.
- That is, the library will use all of the mechanisms for allocating
- space.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>2</code></td>
- <td>This is the HDF5 Library&rsquo;s default file space management strategy.
- With this strategy, the library&rsquo;s free-space managers track the free space
- that results from the manipulation of HDF5 objects in the HDF5 file.
- The free space information is NOT saved when the file is closed and
- the free space that exists upon file closing becomes unaccounted
- space in the file.
- <br />
- As with strategy #1, the library will try all of the mechanisms
- for allocating space. When space is needed for file metadata or
- raw data, the library first requests space from the free-space
- managers. If the request is not satisfied, the library requests
- space from the aggregators. If the request is still not satisfied,
- the library requests space from the virtual file driver.
- </td>
- </tr>
-
- <tr>
- <td align="center"><code>3</code></td>
- <td>With this strategy, the HDF5 Library does not track free space that results
- from the manipulation of HDF5 objects in the HDF5 file and
- the free space becomes unaccounted space in the file.
- <br />
- When space is needed for file metadata or raw data,
- the library first requests space from the aggregators.
- If the request is not satisfied, the library requests space from
- the virtual file driver.
- </td>
- </tr>
- <tr>
- <td align="center"><code>4</code></td>
- <td>With this strategy, the HDF5 Library does not track free space that results
- from the manipulation of HDF5 objects in the HDF5 file and
- the free space becomes unaccounted space in the file.
- <br />
- When space is needed for file metadata or raw data,
- the library requests space from the virtual file driver.
- </td>
- </tr>
- </table></p>
- </td>
- </tr>
-
- <tr>
- <td><p>Threshold</p></td>
- <td><p>This is the free-space section threshold.
- The library&rsquo;s free-space managers will track only
- free-space sections with size greater than or equal to
- <em>threshold</em>. The default is to track free-space
- sections of all sizes.</p>
- </td>
- </tr>
- <tr>
- <td><p>Superblock Free-space Manager Address</p></td>
- <td><p>This is the address of the free-space manager for
- H5FD_MEM_SUPER allocation type.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>B-tree Free-space Manager Address</p></td>
- <td><p>This is the address of the free-space manager for
- H5FD_MEM_BTREE allocation type.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Raw Data Free-space Manager Address</p></td>
- <td><p>This is the address of the free-space manager for
- H5FD_MEM_DRAW allocation type.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Global Heap Free-space Manager Address</p></td>
- <td><p>This is the address of the free-space manager for
- H5FD_MEM_GHEAP allocation type.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Local Heap Free-space Manager Address</p></td>
- <td><p>This is the address of the free-space manager for
- H5FD_MEM_LHEAP allocation type.
- </p>
- </td>
- </tr>
-
- <tr>
- <td><p>Object Header Free-space Manager Address</p></td>
- <td><p>This is the address of the free-space manager for
- H5FD_MEM_OHDR allocation type.
- </p>
- </td>
- </tr>
- </table>
- </div>
- <br />
+<br />
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Field Name</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td><p>Version</p></td>
+ <td><p>This is the version number of this message. This
+ document describes version 0.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Strategy</p></td>
+ <td><p>This is the file space management strategy for the
+ file. There are four types of strategies:</p>
+ <table class="list">
+ <tr>
+ <th width="20%" align="center">Value</th>
+ <th width="80%" align="left">Description</th>
+ </tr>
+
+ <tr>
+ <td align="center"><code>1</code></td>
+ <td>With this strategy, the HDF5 Library&rsquo;s free-space
+ managers track the free space that results from the manipulation
+ of HDF5 objects in the HDF5 file. The free space information is
+ saved when the file is closed, and reloaded when the file is
+ reopened. <br /> When space is needed for file metadata or raw
+ data, the HDF5 Library first requests space from the
+ library&rsquo;s free-space managers. If the request is not
+ satisfied, the library requests space from the aggregators. If
+ the request is still not satisfied, the library requests space
+ from the virtual file driver. That is, the library will use all
+ of the mechanisms for allocating space.
+ </td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>2</code></td>
+ <td>This is the HDF5 Library&rsquo;s default file space
+ management strategy. With this strategy, the library&rsquo;s
+ free-space managers track the free space that results from the
+ manipulation of HDF5 objects in the HDF5 file. The free space
+ information is NOT saved when the file is closed and the free
+ space that exists upon file closing becomes unaccounted space in
+ the file. <br /> As with strategy #1, the library will try all
+ of the mechanisms for allocating space. When space is needed for
+ file metadata or raw data, the library first requests space from
+ the free-space managers. If the request is not satisfied, the
+ library requests space from the aggregators. If the request is
+ still not satisfied, the library requests space from the virtual
+ file driver.
+ </td>
+ </tr>
+
+ <tr>
+ <td align="center"><code>3</code></td>
+ <td>With this strategy, the HDF5 Library does not track free
+ space that results from the manipulation of HDF5 objects in the
+ HDF5 file and the free space becomes unaccounted space in the
+ file. <br /> When space is needed for file metadata or raw data,
+ the library first requests space from the aggregators. If the
+ request is not satisfied, the library requests space from the
+ virtual file driver.
+ </td>
+ </tr>
+ <tr>
+ <td align="center"><code>4</code></td>
+ <td>With this strategy, the HDF5 Library does not track free
+ space that results from the manipulation of HDF5 objects in the
+ HDF5 file and the free space becomes unaccounted space in the
+ file. <br /> When space is needed for file metadata or raw data,
+ the library requests space from the virtual file driver.
+ </td>
+ </tr>
+ </table>
+ <p></p></td>
+ </tr>
+
+ <tr>
+ <td><p>Threshold</p></td>
+ <td><p>
+ This is the free-space section threshold. The library&rsquo;s
+ free-space managers will track only free-space sections with size
+ greater than or equal to <em>threshold</em>. The default is to
+ track free-space sections of all sizes.
+ </p></td>
+ </tr>
+ <tr>
+ <td><p>Superblock Free-space Manager Address</p></td>
+ <td><p>This is the address of the free-space manager for
+ H5FD_MEM_SUPER allocation type.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>B-tree Free-space Manager Address</p></td>
+ <td><p>This is the address of the free-space manager for
+ H5FD_MEM_BTREE allocation type.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Raw Data Free-space Manager Address</p></td>
+ <td><p>This is the address of the free-space manager for
+ H5FD_MEM_DRAW allocation type.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Global Heap Free-space Manager Address</p></td>
+ <td><p>This is the address of the free-space manager for
+ H5FD_MEM_GHEAP allocation type.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Local Heap Free-space Manager Address</p></td>
+ <td><p>This is the address of the free-space manager for
+ H5FD_MEM_LHEAP allocation type.</p></td>
+ </tr>
+
+ <tr>
+ <td><p>Object Header Free-space Manager Address</p></td>
+ <td><p>This is the address of the free-space manager for
+ H5FD_MEM_OHDR allocation type.</p></td>
+ </tr>
+ </table>
+</div>
+<br />
<br />
-<h3><a name="DataStorage">
-IV.B. Disk Format: Level 2B - Data Object Data Storage</a></h3>
+<h3>
+ <a name="DataStorage"> IV.B. Disk Format: Level 2B - Data Object
+ Data Storage</a>
+</h3>
<p>The data for an object is stored separately from its header
- information in the file and may not actually be located in the HDF5 file
- itself if the header indicates that the data is stored externally. The
- information for each record in the object is stored according to the
- dimensionality of the object (indicated in the dataspace header message).
- Multi-dimensional array data is stored in C order; in other words, the
- &ldquo;last&rdquo; dimension changes fastest.</p>
-
-<p>Data whose elements are composed of atomic datatypes are stored in IEEE
- format, unless they are specifically defined as being stored in a different
- machine format with the architecture-type information from the datatype
- header message. This means that each architecture will need to [potentially]
- byte-swap data values into the internal representation for that particular
- machine.</p>
-
-<p> Data with a variable-length datatype is stored in the global heap
- of the HDF5 file. Global heap identifiers are stored in the
- data object storage.</p>
-
-<p>Data whose elements are composed of reference datatypes are stored in
- several different ways depending on the particular reference type involved.
- Object pointers are just stored as the offset of the object header being
- pointed to with the size of the pointer being the same number of bytes as
- offsets in the file.</p>
+ information in the file and may not actually be located in the HDF5
+ file itself if the header indicates that the data is stored externally.
+ The information for each record in the object is stored according to
+ the dimensionality of the object (indicated in the dataspace header
+ message). Multi-dimensional array data is stored in C order; in other
+ words, the &ldquo;last&rdquo; dimension changes fastest.</p>
+
+<p>Data whose elements are composed of atomic datatypes are stored
+ in IEEE format, unless they are specifically defined as being stored in
+ a different machine format with the architecture-type information from
+ the datatype header message. This means that each architecture will
+ need to [potentially] byte-swap data values into the internal
+ representation for that particular machine.</p>
+
+<p>Data with a variable-length datatype is stored in the global heap
+ of the HDF5 file. Global heap identifiers are stored in the data object
+ storage.</p>
+
+<p>Data whose elements are composed of reference datatypes are
+ stored in several different ways depending on the particular reference
+ type involved. Object pointers are just stored as the offset of the
+ object header being pointed to with the size of the pointer being the
+ same number of bytes as offsets in the file.</p>
<p>Dataset region references are stored as a heap-ID which points to
-the following information within the file-heap: an offset of the object
-pointed to, number-type information (same format as header message),
-dimensionality information (same format as header message), sub-set start
-and end information (in other words, a coordinate location for each),
-and field start and end names (in other words, a [pointer to the] string
-indicating the first field included and a [pointer to the] string name
-for the last field). </p>
+ the following information within the file-heap: an offset of the object
+ pointed to, number-type information (same format as header message),
+ dimensionality information (same format as header message), sub-set
+ start and end information (in other words, a coordinate location for
+ each), and field start and end names (in other words, a [pointer to
+ the] string indicating the first field included and a [pointer to the]
+ string name for the last field).</p>
-<p>Data of a compound datatype is stored as a contiguous stream of the items
- in the structure, with each item formatted according to its datatype.</p>
+<p>Data of a compound datatype is stored as a contiguous stream of
+ the items in the structure, with each item formatted according to its
+ datatype.</p>
<br />
<br />
<hr />
-<h2><a name="AppendixA">
-V. Appendix A: Definitions</a></h2>
+<h2>
+ <a name="AppendixA"> V. Appendix A: Definitions</a>
+</h2>
-<p>Definitions of various terms used in this document are included in
-this section.</p>
+<p>Definitions of various terms used in this document are included
+ in this section.</p>
- <div align="center">
+<div align="center">
<table class="glossary">
- <tr>
- <th width="20%">Term</th>
- <th>Definition</th>
- </tr>
+ <tr>
+ <th width="20%">Term</th>
+ <th>Definition</th>
+ </tr>
- <tr>
- <td>Undefined Address</td>
- <td>The <a name="UndefinedAddress">undefined
- address</a> for a file is a file address with all bits
- set: in other words, <code>0xffff...ff</code>.</td>
- </tr>
+ <tr>
+ <td>Undefined Address</td>
+ <td>The <a name="UndefinedAddress">undefined address</a> for a
+ file is a file address with all bits set: in other words, <code>0xffff...ff</code>.
+ </td>
+ </tr>
- <tr>
- <td>Unlimited Size</td>
- <td>The <a name="UnlimitedDim">unlimited size</a>
- for a size is a value with all bits set: in other words,
- <code>0xffff...ff</code>.</td>
- </tr>
+ <tr>
+ <td>Unlimited Size</td>
+ <td>The <a name="UnlimitedDim">unlimited size</a> for a size is
+ a value with all bits set: in other words, <code>0xffff...ff</code>.
+ </td>
+ </tr>
</table>
- </div>
+</div>
<br />
<br />
<hr />
-<h2><a name="AppendixB">
-VI. Appendix B: File Memory Allocation Types</a></h2>
+<h2>
+ <a name="AppendixB"> VI. Appendix B: File Memory Allocation Types</a>
+</h2>
-<p>There are six basic types of file memory allocation as follows:
-</p>
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Basic Allocation Type</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td>H5FD_MEM_SUPER</td>
- <td>File memory allocated for <em>Superblock.</em></td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_BTREE</td>
- <td>File memory allocated for <em>B-tree.</em></td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_DRAW</td>
- <td>File memory allocated for raw data.</td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_GHEAP</td>
- <td>File memory allocated for <em>Global Heap.</em></td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_LHEAP</td>
- <td>File memory allocated for <em>Local Heap.</em></td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_OHDR</td>
- <td>File memory allocated for <em>Object Header.</em></td>
- </tr>
- </table>
- </div>
+<p>There are six basic types of file memory allocation as follows:</p>
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Basic Allocation Type</th>
+ <th>Description</th>
+ </tr>
-<p>There are other file memory allocation types that are mapped to the
-above six basic allocation types because they are similar in nature.
-The mapping is listed in the following table:
-</p>
+ <tr>
+ <td>H5FD_MEM_SUPER</td>
+ <td>File memory allocated for <em>Superblock.</em></td>
+ </tr>
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Basic Allocation Type</th>
- <th>Mapping of Allocation Types to Basic Allocation Types</th>
- </tr>
-
- <tr>
- <td>H5FD_MEM_SUPER</td>
- <td><em>none</em></td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_BTREE</td>
- <td>H5FD_MEM_SOHM_INDEX</td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_DRAW</td>
- <td>H5FD_MEM_FHEAP_HUGE_OBJ</td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_GHEAP</td>
- <td><em>none</em></td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_LHEAP</td>
- <td>H5FD_MEM_FHEAP_DBLOCK, H5FD_MEM_FSPACE_SINFO</td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_OHDR</td>
- <td>H5FD_MEM_FHEAP_HDR, H5FD_MEM_FHEAP_IBLOCK, H5FD_MEM_FSPACE_HDR, H5FD_MEM_SOHM_TABLE</td>
- </tr>
- </table>
- </div>
+ <tr>
+ <td>H5FD_MEM_BTREE</td>
+ <td>File memory allocated for <em>B-tree.</em></td>
+ </tr>
-<p>Allocation types that are mapped to basic allocation types are described below:
-</p>
+ <tr>
+ <td>H5FD_MEM_DRAW</td>
+ <td>File memory allocated for raw data.</td>
+ </tr>
- <div align="center">
- <table class="desc">
- <tr>
- <th width="30%">Allocation Type</th>
- <th>Description</th>
- </tr>
-
- <tr>
- <td>H5FD_MEM_FHEAP_HDR</td>
- <td>File memory allocated for <em>Fractal Heap Header.</em></td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_FHEAP_DBLOCK</td>
- <td>File memory allocated for <em>Fractal Heap Direct Blocks.</em></td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_FHEAP_IBLOCK</td>
- <td>File memory allocated for <em>Fractal Heap Indirect Blocks.</em></td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_FHEAP_HUGE_OBJ</td>
- <td>File memory allocated for huge objects in the fractal heap.</td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_FSPACE_HDR</td>
- <td>File memory allocated for <em>Free-space Manager Header.</em></td>
- </tr>
-
- <tr>
- <td>H5FD_MEM_FSPACE_SINFO</td>
- <td>File memory allocated for <em>Free-space Section List</em> of the free-space manager.</td>
- </tr>
- <tr>
- <td>H5FD_MEM_SOHM_TABLE</td>
- <td>File memory allocated for <em>Shared Object Header Message Table.</em></td>
- </tr>
- <tr>
- <td>H5FD_MEM_SOHM_INDEX</td>
- <td>File memory allocated for <em>Shared Message Record List.</em></td>
- </tr>
- </table>
- </div>
-</body>
+ <tr>
+ <td>H5FD_MEM_GHEAP</td>
+ <td>File memory allocated for <em>Global Heap.</em></td>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_LHEAP</td>
+ <td>File memory allocated for <em>Local Heap.</em></td>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_OHDR</td>
+ <td>File memory allocated for <em>Object Header.</em></td>
+ </tr>
+ </table>
+</div>
+
+<p>There are other file memory allocation types that are mapped to
+ the above six basic allocation types because they are similar in
+ nature. The mapping is listed in the following table:</p>
+
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Basic Allocation Type</th>
+ <th>Mapping of Allocation Types to Basic Allocation Types</th>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_SUPER</td>
+ <td><em>none</em></td>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_BTREE</td>
+ <td>H5FD_MEM_SOHM_INDEX</td>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_DRAW</td>
+ <td>H5FD_MEM_FHEAP_HUGE_OBJ</td>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_GHEAP</td>
+ <td><em>none</em></td>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_LHEAP</td>
+ <td>H5FD_MEM_FHEAP_DBLOCK, H5FD_MEM_FSPACE_SINFO</td>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_OHDR</td>
+ <td>H5FD_MEM_FHEAP_HDR, H5FD_MEM_FHEAP_IBLOCK,
+ H5FD_MEM_FSPACE_HDR, H5FD_MEM_SOHM_TABLE</td>
+ </tr>
+ </table>
+</div>
+
+<p>Allocation types that are mapped to basic allocation types are
+ described below:</p>
+
+<div align="center">
+ <table class="desc">
+ <tr>
+ <th width="30%">Allocation Type</th>
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_FHEAP_HDR</td>
+ <td>File memory allocated for <em>Fractal Heap Header.</em></td>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_FHEAP_DBLOCK</td>
+ <td>File memory allocated for <em>Fractal Heap Direct
+ Blocks.</em></td>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_FHEAP_IBLOCK</td>
+ <td>File memory allocated for <em>Fractal Heap Indirect
+ Blocks.</em></td>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_FHEAP_HUGE_OBJ</td>
+ <td>File memory allocated for huge objects in the fractal heap.</td>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_FSPACE_HDR</td>
+ <td>File memory allocated for <em>Free-space Manager
+ Header.</em></td>
+ </tr>
+
+ <tr>
+ <td>H5FD_MEM_FSPACE_SINFO</td>
+ <td>File memory allocated for <em>Free-space Section List</em>
+ of the free-space manager.
+ </td>
+ </tr>
+ <tr>
+ <td>H5FD_MEM_SOHM_TABLE</td>
+ <td>File memory allocated for <em>Shared Object Header
+ Message Table.</em></td>
+ </tr>
+ <tr>
+ <td>H5FD_MEM_SOHM_INDEX</td>
+ <td>File memory allocated for <em>Shared Message Record
+ List.</em></td>
+ </tr>
+ </table>
+</div>
+</head>
+<body></body>
</html>
diff --git a/doxygen/examples/H5.format.html b/doxygen/examples/H5.format.html
index 47e19bf..9134d35 100644
--- a/doxygen/examples/H5.format.html
+++ b/doxygen/examples/H5.format.html
@@ -418,7 +418,7 @@
<p>This document describes the lower-level data objects;
the higher-level objects and their properties are described
- in the <a href="UG/HDF5_Users_Guide-Responsive HTML5/index.html"><cite>HDF5 User&rsquo;s Guide</cite></a>.</p>
+ in the <a href="UG/HDF5_User_Guide-Responsive HTML5/index.html"><cite>HDF5 User Guide</cite></a>.</p>
<p>Three levels of information comprise the file format.
Level 0 contains basic information for identifying and
diff --git a/doxygen/examples/ThreadSafeLibrary.html b/doxygen/examples/ThreadSafeLibrary.html
index 97f7742..5824dc6 100644
--- a/doxygen/examples/ThreadSafeLibrary.html
+++ b/doxygen/examples/ThreadSafeLibrary.html
@@ -20,9 +20,9 @@ The following code is placed at the beginning of H5private.h:
</blockquote>
<p>
-<code>H5_HAVE_THREADSAFE</code> is defined when the HDF-5 library is
+<code>H5_HAVE_THREADSAFE</code> is defined when the HDF5 library is
compiled with the --enable-threadsafe configuration option. In general,
-code for the non-threadsafe version of HDF-5 library are placed within
+code for the non-threadsafe version of HDF5 library are placed within
the <code>#else</code> part of the conditional compilation. The exception
to this rule are the changes to the <code>FUNC_ENTER</code> (in
H5private.h), <code>HRETURN</code> and <code>HRETURN_ERROR</code> (in
@@ -438,7 +438,7 @@ described in Appendix D and may be found in <code>H5TS.c</code>.
<p>
Except where stated, all tests involve 16 simultaneous threads that make
-use of HDF-5 API calls without any explicit synchronization typically
+use of HDF5 API calls without any explicit synchronization typically
required in a non-threadsafe environment.
</p>
@@ -453,7 +453,7 @@ dataset's named value.
<p>
The main thread would join with all 16 threads and attempt to match the
-resulting HDF-5 file with expected results - that each dataset contains
+resulting HDF5 file with expected results - that each dataset contains
the correct value (0 for <i>zero</i>, 1 for <i>one</i> etc ...) and all
datasets were correctly created.
</p>
@@ -473,7 +473,7 @@ name.
<p>
The error stack implementation runs correctly if it reports 15 instances
-of the dataset name conflict error and finally generates a correct HDF-5
+of the dataset name conflict error and finally generates a correct HDF5
containing that single dataset. Each thread should report its own stack
of errors with a thread number associated with it.
</p>
diff --git a/doxygen/examples/core_menu.md b/doxygen/examples/core_menu.md
new file mode 100644
index 0000000..3fd7d11
--- /dev/null
+++ b/doxygen/examples/core_menu.md
@@ -0,0 +1,69 @@
+<b>Core Library</b>
+
+- @ref H5A "Attributes (H5A)"
+<br />
+HDF5 attribute is a small metadata object describing the nature and/or intended usage of a primary data object.
+
+- @ref H5D "Datasets (H5D)"
+<br />
+Manage HDF5 datasets, including the transfer of data between memory and disk and the description of dataset properties.
+
+- @ref H5S "Dataspaces (H5S)"
+<br />
+HDF5 dataspaces describe the shape of datasets in memory or in HDF5 files.
+
+- @ref H5T "Datatypes (H5T)"
+<br />
+HDF5 datatypes describe the element type of HDF5 datasets and attributes.
+
+- @ref H5E "Error Handling (H5E)"
+<br />
+HDF5 library error reporting.
+
+- @ref H5ES "Event Set (H5ES)"
+<br />
+HDF5 event set life cycle used with HDF5 VOL connectors that enable the asynchronous feature in HDF5.
+
+- @ref H5F "Files (H5F)"
+<br />
+Manage HDF5 files.
+
+- @ref H5Z "Filters (H5Z)"
+<br />
+Manage HDF5 user-defined filters
+
+- @ref H5G "Groups (H5G)"
+<br />
+Manage HDF5 groups.
+
+- @ref H5I "Identifiers (H5I)"
+<br />
+Manage identifiers defined by the HDF5 library.
+
+- @ref H5 "Library General (H5)"
+<br />
+Manage the life cycle of HDF5 library instances.
+
+- @ref H5L "Links (H5L)"
+<br />
+Manage HDF5 links and link types.
+
+- @ref H5O "Objects (H5O)"
+<br />
+Manage HDF5 objects (groups, datasets, datatype objects).
+
+- @ref H5P "Property Lists (H5P)"
+<br />
+HDF5 property lists are the main vehicle to configure the behavior of HDF5 API functions.
+
+- @ref H5PL "Dynamically-loaded Plugins (H5PL)"
+<br />
+Manage the loading behavior of HDF5 plugins.
+
+- @ref H5R "References (H5R)"
+<br />
+Manage HDF5 references (HDF5 objects, attributes, and selections on datasets a.k.a. dataset regions).
+
+- @ref H5VL "VOL Connector (H5VL)"
+<br />
+Manage HDF5 VOL connector plugins.
diff --git a/doxygen/examples/fortran_menu.md b/doxygen/examples/fortran_menu.md
new file mode 100644
index 0000000..8ef4ead
--- /dev/null
+++ b/doxygen/examples/fortran_menu.md
@@ -0,0 +1,73 @@
+<b>Fortran Library</b>
+
+- @ref FH5A "Attributes (H5A)"
+<br />
+HDF5 attribute is a small metadata object describing the nature and/or intended usage of a primary data object.
+
+- @ref FH5D "Datasets (H5D)"
+<br />
+Manage HDF5 datasets, including the transfer of data between memory and disk and the description of dataset properties.
+
+- @ref FH5S "Dataspaces (H5S)"
+<br />
+HDF5 dataspaces describe the shape of datasets in memory or in HDF5 files.
+
+- @ref FH5T "Datatypes (H5T)"
+<br />
+HDF5 datatypes describe the element type of HDF5 datasets and attributes.
+
+- @ref FH5E "Error Handling (H5E)"
+<br />
+HDF5 library error reporting.
+
+- @ref FH5F "Files (H5F)"
+<br />
+Manage HDF5 files.
+
+- @ref FH5Z "Filters (H5Z)"
+<br />
+Manage HDF5 user-defined filters
+
+- @ref FH5G "Groups (H5G)"
+<br />
+Manage HDF5 groups.
+
+- @ref FH5I "Identifiers (H5I)"
+<br />
+Manage identifiers defined by the HDF5 library.
+
+- @ref FH5 "Library General (H5)"
+<br />
+Manage the life cycle of HDF5 library instances.
+
+- @ref FH5L "Links (H5L)"
+<br />
+Manage HDF5 links and link types.
+
+- @ref FH5O "Objects (H5O)"
+<br />
+Manage HDF5 objects (groups, datasets, datatype objects).
+
+- @ref FH5P "Property Lists (H5P)"
+<br />
+HDF5 property lists are the main vehicle to configure the behavior of HDF5 API functions.
+
+- @ref FH5R "References (H5R)"
+<br />
+Manage HDF5 references (HDF5 objects, attributes, and selections on datasets a.k.a. dataset regions).
+
+- @ref FH5LT "High Level Lite (H5LT)"
+<br />
+Functions to simplify creating and manipulating datasets, attributes and other features
+
+- @ref FH5IM "High Level Image (H5IM)"
+<br />
+Creating and manipulating HDF5 datasets intended to be interpreted as images
+
+- @ref FH5TB "High Level Table (H5TB)"
+<br />
+Creating and manipulating HDF5 datasets intended to be interpreted as tables
+
+- @ref FH5DS "High Level Dimension Scale (H5DS)"
+<br />
+Creating and manipulating HDF5 datasets that are associated with the dimension of another HDF5 dataset
diff --git a/doxygen/examples/high_level_menu.md b/doxygen/examples/high_level_menu.md
new file mode 100644
index 0000000..d209bf4
--- /dev/null
+++ b/doxygen/examples/high_level_menu.md
@@ -0,0 +1,30 @@
+<b>High-level library</b>
+<br />
+The high-level HDF5 library includes several sets of convenience and standard-use APIs to
+facilitate common HDF5 operations.
+
+- @ref H5LT
+<br />
+Functions to simplify creating and manipulating datasets, attributes and other features
+
+- @ref H5IM
+<br />
+Creating and manipulating HDF5 datasets intended to be interpreted as images
+
+- @ref H5TB
+<br />
+Creating and manipulating HDF5 datasets intended to be interpreted as tables
+
+- @ref H5PT
+<br />
+Creating and manipulating HDF5 datasets to support append- and read-only operations on table data
+
+- @ref H5DS
+<br />
+Creating and manipulating HDF5 datasets that are associated with the dimension of another HDF5 dataset
+
+- @ref H5DO
+<br />
+Bypassing default HDF5 behavior in order to optimize for specific use cases
+
+- @ref H5LR "Extensions (H5LR, H5LT)"
diff --git a/doxygen/examples/java_menu.md b/doxygen/examples/java_menu.md
new file mode 100644
index 0000000..1236838
--- /dev/null
+++ b/doxygen/examples/java_menu.md
@@ -0,0 +1,84 @@
+<b>Java Library</b>
+ @ref HDF5LIB
+
+- @ref JH5
+<br />
+This package is the Java interface for the HDF5 library.
+
+- @ref JH5A
+<br />
+This package is the Java interface for the HDF5 library attribute APIs.
+
+- @ref JH5D
+<br />
+This package is the Java interface for the HDF5 library dataset APIs.
+
+- @ref JH5S
+<br />
+This package is the Java interface for the HDF5 library dataspace APIs.
+
+- @ref JH5T
+<br />
+This package is the Java interface for the HDF5 library datatype APIs.
+
+- @ref JH5E
+<br />
+This package is the Java interface for the HDF5 library error APIs.
+
+- @ref JH5F
+<br />
+This package is the Java interface for the HDF5 library file APIs.
+
+- @ref JH5Z
+<br />
+This package is the Java interface for the HDF5 library filter APIs.
+
+- @ref JH5G
+<br />
+This package is the Java interface for the HDF5 library group APIs.
+
+- @ref JH5I
+<br />
+This package is the Java interface for the HDF5 library identifier APIs.
+
+- @ref JH5L
+<br />
+This package is the Java interface for the HDF5 library links APIs.
+
+- @ref JH5O
+<br />
+This package is the Java interface for the HDF5 library object APIs.
+
+- @ref JH5P
+<br />
+This package is the Java interface for the HDF5 library property list APIs.
+
+- @ref JH5PL
+<br />
+This package is the Java interface for the HDF5 library plugin APIs.
+
+- @ref JH5R
+<br />
+This package is the Java interface for the HDF5 library reference APIs.
+
+- @ref JH5VL
+<br />
+This package is the Java interface for the HDF5 library VOL connector APIs.
+
+- @ref HDF5CONST
+<br />
+This class contains C constants and enumerated types of HDF5 library.
+
+- @ref HDFNATIVE
+<br />
+This class encapsulates native methods to deal with arrays of numbers,
+ * converting from numbers to bytes and bytes to numbers.
+
+- @ref HDFARRAY
+<br />
+This is a class for handling multidimensional arrays for HDF.
+
+- @ref ERRORS
+<br />
+The class HDF5Exception returns errors from the Java HDF5 Interface.
+ \ No newline at end of file