<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN"> <html> <head> <title>DDL for HDF5</title> <!-- #BeginLibraryItem "/ed_libs/styles_UG.lbi" --> <!-- * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Copyright by the Board of Trustees of the University of Illinois. * * All rights reserved. * * * * This file is part of HDF5. The full HDF5 copyright notice, including * * terms governing use, modification, and redistribution, is contained in * * the files COPYING and Copyright.html. COPYING can be found at the root * * of the source code distribution tree; Copyright.html can be found at the * * root level of an installed copy of the electronic HDF5 document set and * * is linked from the top-level documents page. It can also be found at * * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html. If you do not have * * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * --> <link href="ed_styles/UGelect.css" rel="stylesheet" type="text/css"> <!-- #EndLibraryItem --></head> <body bgcolor="#FFFFFF"> <!-- #BeginLibraryItem "/ed_libs/NavBar_UG.lbi" --><hr> <center> <table border=0 width=98%> <tr><td valign=top align=left> <a href="index.html">HDF5 documents and links</a> <br> <a href="H5.intro.html">Introduction to HDF5</a> <br> <a href="RM_H5Front.html">HDF5 Reference Manual</a> <br> <a href="http://hdf.ncsa.uiuc.edu/HDF5/doc/UG/index.html">HDF5 User's Guide for Release 1.6</a> <br> <!-- <a href="Glossary.html">Glossary</a><br> --> </td> <td valign=top align=right> And in this document, the <a href="H5.user.html"><strong>HDF5 User's Guide from Release 1.4.5:</strong></a> <br> <a href="Files.html">Files</a> <a href="Datasets.html">Datasets</a> <a href="Datatypes.html">Datatypes</a> <a href="Dataspaces.html">Dataspaces</a> <a href="Groups.html">Groups</a> <br> <a href="References.html">References</a> <a href="Attributes.html">Attributes</a> <a href="Properties.html">Property Lists</a> <a href="Errors.html">Error Handling</a> <br> <a href="Filters.html">Filters</a> <a href="Caching.html">Caching</a> <a href="Chunking.html">Chunking</a> <a href="MountingFiles.html">Mounting Files</a> <br> <a href="Performance.html">Performance</a> <a href="Debugging.html">Debugging</a> <a href="Environment.html">Environment</a> <a href="ddl.html">DDL</a> </td></tr> </table> </center> <hr> <!-- #EndLibraryItem --><h1>DDL in BNF for HDF5</h1> <h2>1. Introduction</h2> This document contains the data description language (DDL) for an HDF5 file. The description is in Backus-Naur Form. <h2>2. Explanation of Symbols</h2> This section contains a brief explanation of the symbols used in the DDL. <PRE> ::= defined as <tname> a token with the name tname <a> | <b> one of <a> or <b> <a><FONT SIZE=1.7>opt</FONT> zero or one occurrence of <a> <a>* zero or more occurrence of <a> <a>+ one or more occurrence of <a> [0-9] an element in the range between 0 and 9 `[' the token within the quotes (used for special characters) TBD To Be Decided </pre> <h2>3. The DDL</h2> <dir> <pre> <file> ::= HDF5 <file_name> { <file_super_block><FONT SIZE=1.7>opt</FONT> <root_group> } <file_name> ::= <identifier> <file_super_block> ::= BOOT_BLOCK { <super_block_content> } <super_block_content> ::= TBD <root_group> ::= GROUP "/" { <unamed_datatype>* <object_id><FONT SIZE=1.7>opt</FONT> <group_comment><FONT SIZE=1.7>opt</FONT> <group_attribute>* <group_member>* } <datatype> ::= <atomic_type> | <compound_type> | <variable_length_type> | <array_type> <unamed_datatype> ::= DATATYPE <unamed_type_name> { <datatype> } <unamed_type_name> ::= the assigned name for unamed type is in the form of #oid, where oid is the object id of the type <atomic_type> ::= <integer> | <float> | <time> | <string> | <bitfield> | <opaque> | <reference> | <enum> <integer> ::= H5T_STD_I8BE | H5T_STD_I8LE | H5T_STD_I16BE | H5T_STD_I16LE | H5T_STD_I32BE | H5T_STD_I32LE | H5T_STD_I64BE | H5T_STD_I64LE | H5T_STD_U8BE | H5T_STD_U8LE | H5T_STD_U16BE | H5T_STD_U16LE | H5T_STD_U32BE | H5T_STD_U32LE | H5T_STD_U64BE | H5T_STD_U64LE | H5T_NATIVE_CHAR | H5T_NATIVE_UCHAR | H5T_NATIVE_SHORT | H5T_NATIVE_USHORT | H5T_NATIVE_INT | H5T_NATIVE_UINT | H5T_NATIVE_LONG | H5T_NATIVE_ULONG | H5T_NATIVE_LLONG | H5T_NATIVE_ULLONG <float> ::= H5T_IEEE_F32BE | H5T_IEEE_F32LE | H5T_IEEE_F64BE | H5T_IEEE_F64LE | H5T_NATIVE_FLOAT | H5T_NATIVE_DOUBLE | H5T_NATIVE_LDOUBLE <time> ::= TBD <string> ::= H5T_STRING { STRSIZE <strsize> ; STRPAD <strpad> ; CSET <cset> ; CTYPE <ctype> ; } <strsize> ::= <int_value> <strpad> ::= H5T_STR_NULLTERM | H5T_STR_NULLPAD | H5T_STR_SPACEPAD <cset> ::= H5T_CSET_ASCII <ctype> ::= H5T_C_S1 | H5T_FORTRAN_S1 <bitfield> ::= TBD <opaque> ::= H5T_OPAQUE { <identifier> } <reference> ::= H5T_REFERENCE { <ref_type> } <ref_type> ::= H5T_STD_REF_OBJECT | H5T_STD_REF_DSETREG <compound_type> ::= H5T_COMPOUND { <member_type_def>+ } <member_type_def> ::= <datatype> <field_name> ; <field_name> ::= <identifier> <variable_length_type> ::= H5T_VLEN { <datatype> } <array_type> ::= H5T_ARRAY { <dim_sizes> <datatype> } <dim_sizes> ::= `['<dimsize>`]' | `['<dimsize>`]'<dim_sizes> <dimsize> ::= <int_value> <attribute> ::= ATTRIBUTE <attr_name> { <dataset_type> <dataset_space> <data><FONT SIZE=1.7>opt</FONT> } <attr_name> ::= <identifier> <dataset_type> ::= DATATYPE <path_name> | <datatype> <enum> ::= H5T_ENUM { <enum_base_type> <enum_def>+ } <enum_base_type> ::= <integer> // Currently enums can only hold integer type data, but they may be expanded // in the future to hold any datatype <enum_def> ::= <enum_symbol> <enum_val>; <enum_symbol> ::= <identifier> <enum_val> ::= <int_value> <path_name> ::= <path_part>+ <path_part> ::= /<identifier> <dataspace> ::= <scalar_space> | <simple_space> | <complex_space> <scalar_space> ::= SCALAR <simple_space> ::= SIMPLE { <current_dims> / <max_dims> } <complex_space> ::= COMPLEX { <complex_space_definition> } <dataset_space> ::= DATASPACE <path_name> | <dataspace> <current_dims> ::= <dims> <max_dims> ::= `(' <max_dim_list> `)' <max_dim_list> ::= <max_dim> | <max_dim>, <max_dim_list> <max_dim> ::= <int_value> | H5S_UNLIMITED <complex_space_definition> ::= TBD <data> ::= DATA { <scalar_space_data> | <simple_space_data> | <complex_space_data> } | <subset> <scalar_space_data> ::= <any_element> <any_element> ::= <atomic_element> | <compound_element> | <variable_length_element> | <array_element> <any_data_seq> ::= <any_element> | <any_element>, <any_data_seq> <atomic_element> :: = <integer_data> | <float_data> | <time_data> | <string_data> | <bitfield_data> | <opaque_data> | <enum_data> | <reference_data> <subset> ::= SUBSET { <start>; <stride>; <count>; <block>; DATA { <simple_space_data> } } <start> ::= START (<coor_list>) <stride> ::= STRIDE (<pos_list>) <count> ::= COUNT (<coor_list>) <block> ::= BLOCK (<coor_list>) <coor_list> ::= <int_value>, <coor_list> | <int_value> <integer_data> ::= <int_value> <float_data> ::= a floating point number <time_data> ::= TBD <string_data> ::= a string // A string is enclosed in double quotes. // If a string is displayed on more than one line, string concatenate // operator '//'is used. <bitfield_data> ::= TBD <opaque_data> ::= TBD <enum_data> ::= <enum_symbol> <reference_data> ::= <object_ref_data> | <data_region_data> | NULL <object_ref_data> ::= <object_type> <object_num> <object_type> ::= DATASET | GROUP | DATATYPE <object_id> ::= OBJECTID { <object_num> } <object_num> ::= <int_value>:<int_value> | <int_value> <data_region_data> ::= H5T_STD_REF_DSETREG <object_num> { <data_region_data_list> } <data_region_data_list> ::= <data_region_data_info>, <data_region_data_list> | <data_region_data_info> <data_region_data_info> ::= <region_info> | <point_info> <region_info> ::= (<region_vals>) <region_vals> ::= <lower_bound>:<upper_bound>, <region_vals> | <lower_bound>:<upper_bound> <lower_bound> ::= <int_value> <upper_bound> ::= <int_value> <point_info> ::= (<point_vals>) <point_vals> ::= <int_value> | <int_value>, <point_vals> <compound_element> ::= { <any_data_seq> } <atomic_simple_data> :: = <atomic_element>, <atomic_simple_data> | <atomic_element> <simple_space_data> :: = <any_data_seq> <variable_length_element> ::= ( <any_data_seq> ) <array_element> ::= `[' <any_data_seq> `]' <complex_space_data> ::= TBD <named_datatype> ::= DATATYPE <type_name> { <datatype> } <type_name> ::= <identifier> <named_dataspace> ::= TBD <hardlink> ::= HARDLINK <path_name> <group> ::= GROUP <group_name> { <hardlink> | <group_info> } <group_comment> ::= COMMENT <string_data> <group_name> ::= <identifier> <group_info> ::= <object_id><FONT SIZE=1.7>opt</FONT> <group_comment><FONT SIZE=1.7>opt</FONT> <group_attribute>* <group_member>* <group_attribute> ::= <attribute> <group_member> ::= <named_datatype> | <named_dataspace> | <group> | <dataset> | <softlink> <dataset> ::= DATASET <dataset_name> { <hardlink> | <dataset_info> } <dataset_info> ::= <dataset_type> <dataset_space> <storagelayout><FONT SIZE=1.7>opt</FONT> <compression><FONT SIZE=1.7>opt</FONT> <dataset_attribute>* <object_id><FONT SIZE=1.7>opt</FONT> <data><FONT SIZE=1.7>opt</FONT> // Tokens above can be in any order as long as <data> is // after <dataset_type> and <dataset_space>. <dataset_name> ::= <identifier> <storagelayout> :: = STORAGELAYOUT <contiguous_layout> | STORAGELAYOUT <chunked_layout> | STORAGELAYOUT <compact_layout> | STORAGELAYOUT <external_layout> <contiguous_layout> ::= {CONTIGUOUS} // default <chunked_layout> ::= {CHUNKED <dims> } <dims> ::= (<dims_values>) <dims_values> ::= <int_value> | <int_value>, <dims_values> <compact_layout> ::= TBD <external_layout> ::= {EXTERNAL <external_file>+ } <external_file> ::= (<file_name> <offset> <size>) <offset> ::= <int_value> <size> ::= <int_value> <compression> :: = COMPRESSION { TBD } <dataset_attribute> ::= <attribute> <softlink> ::= SOFTLINK <softlink_name> { LINKTARGET <target> } <softlink_name> ::= <identifier> <target> ::= <identifier> <identifier> ::= a string // character '/' should be used with care. <pos_list> ::= <pos_int>, <pos_list> | <pos_int> <int_value> ::= 0 | <pos_int> <pos_int> ::= [1-9][0-9]* </PRE> </DIR> <H2>4. An Example of an HDF5 File in DDL</H2> <DIR> <PRE> HDF5 "example.h5" { GROUP "/" { ATTRIBUTE "attr1" { DATATYPE H5T_STRING { STRSIZE 17; STRPAD H5T_STR_NULLTERM; CSET H5T_CSET_ASCII; CTYPE H5T_C_S1; } DATASPACE SCALAR DATA { "string attribute" } } DATASET "dset1" { DATATYPE H5T_STD_I32BE DATASPACE SIMPLE { ( 10, 10 ) / ( 10, 10 ) } DATA { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 } } DATASET "dset2" { DATATYPE H5T_COMPOUND { H5T_STD_I32BE "a"; H5T_IEEE_F32BE "b"; H5T_IEEE_F64BE "c"; } DATASPACE SIMPLE { ( 5 ) / ( 5 ) } DATA { { 1, 0.1, 0.01 }, { 2, 0.2, 0.02 }, { 3, 0.3, 0.03 }, { 4, 0.4, 0.04 }, { 5, 0.5, 0.05 } } } GROUP "group1" { COMMENT "This is a comment for group1"; DATASET "dset3" { DATATYPE "/type1" DATASPACE SIMPLE { ( 5 ) / ( 5 ) } DATA { { [ 0, 1, 2, 3 ], [ 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5 ] }, { [ 0, 1, 2, 3 ], [ 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5 ] }, { [ 0, 1, 2, 3 ], [ 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5 ] }, { [ 0, 1, 2, 3 ], [ 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5 ] }, { [ 0, 1, 2, 3 ], [ 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5 ] } } } } DATASET "dset3" { DATATYPE H5T_VLEN { H5T_STD_I32LE } DATASPACE SIMPLE { ( 4 ) / ( 4 ) } DATA { (0), (10, 11), (20, 21, 22), (30, 31, 32, 33) } } GROUP "group2" { HARDLINK "/group1" } SOFTLINK "slink1" { LINKTARGET "somevalue" } DATATYPE "type1" H5T_COMPOUND { H5T_ARRAY { [4] H5T_STD_I32BE } "a"; H5T_ARRAY { [5][6] H5T_IEEE_F32BE } "b"; } } } </pre> </dir> <!-- #BeginLibraryItem "/ed_libs/NavBar_UG.lbi" --><hr> <center> <table border=0 width=98%> <tr><td valign=top align=left> <a href="index.html">HDF5 documents and links</a> <br> <a href="H5.intro.html">Introduction to HDF5</a> <br> <a href="RM_H5Front.html">HDF5 Reference Manual</a> <br> <a href="http://hdf.ncsa.uiuc.edu/HDF5/doc/UG/index.html">HDF5 User's Guide for Release 1.6</a> <br> <!-- <a href="Glossary.html">Glossary</a><br> --> </td> <td valign=top align=right> And in this document, the <a href="H5.user.html"><strong>HDF5 User's Guide from Release 1.4.5:</strong></a> <br> <a href="Files.html">Files</a> <a href="Datasets.html">Datasets</a> <a href="Datatypes.html">Datatypes</a> <a href="Dataspaces.html">Dataspaces</a> <a href="Groups.html">Groups</a> <br> <a href="References.html">References</a> <a href="Attributes.html">Attributes</a> <a href="Properties.html">Property Lists</a> <a href="Errors.html">Error Handling</a> <br> <a href="Filters.html">Filters</a> <a href="Caching.html">Caching</a> <a href="Chunking.html">Chunking</a> <a href="MountingFiles.html">Mounting Files</a> <br> <a href="Performance.html">Performance</a> <a href="Debugging.html">Debugging</a> <a href="Environment.html">Environment</a> <a href="ddl.html">DDL</a> </td></tr> </table> </center> <hr> <!-- #EndLibraryItem --><!-- #BeginLibraryItem "/ed_libs/Footer.lbi" --><address> <a href="mailto:hdfhelp@ncsa.uiuc.edu">HDF Help Desk</a> <br> Describes HDF5 Release 1.7, the unreleased development branch; working toward HDF5 Release 1.8.0 </address><!-- #EndLibraryItem --> Last modified: 17 November 2000 </body> </html>