From 145fc6d7e7a06429338f7323817bbe9af83ded93 Mon Sep 17 00:00:00 2001 From: Frank Baker Date: Fri, 2 Jul 2004 17:03:17 -0500 Subject: [svn-r8796] Purpose: SZIP and more general filter updates Description: Added SZIP to the introductory paragraphs and as appropriate in the Fortran subroutine descriptions. Revised the introductory discussion, which had previously focussed on one compression filter, to allow for multiple filters of different types. Added list of filters currently distributed with HDF5 to intro. Also some copy edits and minor formatting. Platforms tested: Mozilla, Safari --- doc/html/RM_H5Z.html | 53 +++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 38 insertions(+), 15 deletions(-) diff --git a/doc/html/RM_H5Z.html b/doc/html/RM_H5Z.html index b257609..4b08e69 100644 --- a/doc/html/RM_H5Z.html +++ b/doc/html/RM_H5Z.html @@ -115,30 +115,47 @@ as the corresponding C function. HDF5 supports a filter pipeline that provides the capability for standard and customized raw data processing during I/O operations. HDF5 is distributed with a small set of standard filters such as -compression (gzip and a shuffling algorithm) and +compression (gzip, SZIP, and a shuffling algorithm) and error checking (Fletcher32 checksum). For further flexibility, the library allows a user application to extend the pipeline through the creation and registration of customized filters.

-As mentioned above, one set of filters distributed with HDF5 provides -built-in methods for raw data compression. The flexibility of the filter pipeline implementation enables the definition of additional filters by a user application. -A filter
- —  - is associated with a dataset when the dataset is created,
- —  - can be used only with chunked data (ie., datasets stored in the - H5D_CHUNKED storage layout), and
- —  - is applied independently to each chunk of the dataset. +A filter +

The HDF5 library does not support filters for contiguous datasets because of the difficulty of implementing random access for partial I/O. Compact dataset filters are not supported because it would not produce significant results.

+Filter identifiers for the filters distributed with the HDF5 Library +are as follows: + + + +
+ H5Z_FILTER_DEFLATEThe gzip compression, + or deflation, filter +
+ H5Z_FILTER_SZIPThe SZIP compression filter +
+ H5Z_FILTER_SHUFFLEThe shuffle algorithm filter +
+ H5Z_FILTER_FLETCHER32  The Fletcher32 checksum, + or error checking, filter +
+Custom filters that have been registered with the library will have +additional unique identifiers. +

See The Dataset Interface (H5D) in the HDF5 User's Guide for further information regarding data compression. @@ -160,7 +177,9 @@ data compression.

Returns:
Returns a non-negative value if successful; @@ -175,8 +194,9 @@ SUBROUTINE h5zfilter_avail_f(filter, status, hdferr) ! H5Z_FILTER_DEFLATE_F ! H5Z_FILTER_SHUFFLE_F ! H5Z_FILTER_FLETCHER32_F + ! H5Z_FILTER_SZIP_F LOGICAL, INTENT(OUT) :: status ! Flag indicating whether - ! filter is availble: + ! filter is available: ! .TRUE. ! .FALSE. END SUBROUTINE h5zfilter_avail_f @@ -424,7 +444,9 @@ END SUBROUTINE h5zfilter_avail_f
Returns:
Returns a non-negative value if successful; @@ -438,6 +460,7 @@ SUBROUTINE h5zunregister_f(filter, hdferr) ! H5Z_FILTER_DEFLATE_F ! H5Z_FILTER_SHUFFLE_F ! H5Z_FILTER_FLETCHER32_F + ! H5Z_FILTER_SZIP_F INTEGER, INTENT(OUT) :: hdferr ! Error code ! 0 on success, and -1 on failure END SUBROUTINE h5zunregister_f @@ -492,7 +515,7 @@ And in this document, the Describes HDF5 Release 1.7, the unreleased development branch; working toward HDF5 Release 1.8.0 -- cgit v0.12