Files
hdf5/doc/html/RM_H5Z.html
Frank Baker c340289304 [svn-r5769]
Purpose:
    Bugfix
Description:
    Corrected H5Zregister description, syntax, and parameter descriptions.
    There is one 'function' parameter, rather than the separate
     'compression-function' and 'uncompression-function' parameters that
     were previously listed.
Platforms tested:
    IE 5
2002-07-05 16:13:15 -05:00

168 lines
5.0 KiB
HTML

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<title>
HDF5/H5Z API Specification
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<body bgcolor="#FFFFFF">
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<center>
<table border=0 width=98%>
<tr><td valign=top align=left>
<a href="H5.intro.html">Introduction to HDF5</a>&nbsp;<br>
<a href="H5.user.html">HDF5 User Guide</a>&nbsp;<br>
<a href="index.html">Other HDF5 documents and links</a>&nbsp;<br>
<!--
<a href="Glossary.html">Glossary</a><br>
-->
</td>
<td valign=top align=right>
And in this document, the
<a href="RM_H5Front.html">HDF5 Reference Manual</a>&nbsp;&nbsp;
<br>
<a href="RM_H5.html">H5</a>&nbsp;&nbsp;
<a href="RM_H5A.html">H5A</a>&nbsp;&nbsp;
<a href="RM_H5D.html">H5D</a>&nbsp;&nbsp;
<a href="RM_H5E.html">H5E</a>&nbsp;&nbsp;
<a href="RM_H5F.html">H5F</a>&nbsp;&nbsp;
<a href="RM_H5G.html">H5G</a>&nbsp;&nbsp;
<a href="RM_H5I.html">H5I</a>&nbsp;&nbsp;
<a href="RM_H5P.html">H5P</a>&nbsp;&nbsp;
<br>
<a href="RM_H5R.html">H5R</a>&nbsp;&nbsp;
<a href="RM_H5S.html">H5S</a>&nbsp;&nbsp;
<a href="RM_H5T.html">H5T</a>&nbsp;&nbsp;
H5Z&nbsp;&nbsp;
<a href="Tools.html">Tools</a>&nbsp;&nbsp;
<a href="PredefDTypes.html">Datatypes</a>&nbsp;&nbsp;
</td></tr>
</table>
</center>
<hr>
<center>
<h1>H5Z: Compression Interface</h1>
</center>
<h2>Compression API Functions</h2>
This function enable the user to configure a new compression
method for the local environment.
<table border=0>
<tr><td valign=top>
<ul>
<li><a href="#Compression-Register">H5Zregister</a>
</ul>
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<ul>
&nbsp;
</ul>
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<p>
HDF5 supports compression of raw data by compression methods
built into the library or defined by an application.
A compression method is associated with a dataset when the dataset is
created and is applied independently to each storage chunk of the dataset.
The dataset must use the <code>H5D_CHUNKED</code> storage layout.
<p>
The HDF5 library does not support compression for contiguous datasets
because of the difficulty of implementing random access for partial I/O.
Compact dataset compression is not supported because it would not produce
significant results.
<p>
See <a href="Datasets.html"><cite>The Dataset Interface (H5D)</cite></a>
in the <cite>HDF5 User's Guide</cite> for further information regarding
data compression.
<hr>
<dl>
<dt><strong>Name:</strong> <a name="Compression-Register">H5Zregister</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t</em> <code>H5Zregister</code>(<em>H5Z_method_t</em> <code>method</code>,
<em>const char *</em><code>name</code>,
<em>H5Z_func_t</em> <code>function</code>
)
<dt><strong>Purpose:</strong>
<dd> Registers new compression / uncompression function.
<dt><strong>Description:</strong>
<dd><code>H5Zregister</code> registers a new compression / uncompression
function for the compression method specified by
the method number, <code>method</code>.
<p>
<code>name</code> is used for debugging and may be the null pointer.
<p>
<code>function</code> is a user-defined function providing both
compression and uncompression; it may be the null pointer.
<p>
The statistics associated with a method number are not reset
by this function; they accumulate over the life of the library.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>H5Z_method_t</em> <code>method</code>
<dd>IN: Number specifying compression method.
<dt><em>const char *</em><code>name</code>
<dd>IN: Name associated with the method number.
Used for debugging purposes only.
<dt><em>H5Z_func_t</em> <code>function</code>
<dd>IN: Compression / uncompression method.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
</dl>
<hr>
<center>
<table border=0 width=98%>
<tr><td valign=top align=left>
<a href="H5.intro.html">Introduction to HDF5</a>&nbsp;<br>
<a href="H5.user.html">HDF5 User Guide</a>&nbsp;<br>
<a href="index.html">Other HDF5 documents and links</a>&nbsp;<br>
<!--
<a href="Glossary.html">Glossary</a><br>
-->
</td>
<td valign=top align=right>
And in this document, the
<a href="RM_H5Front.html">HDF5 Reference Manual</a>&nbsp;&nbsp;
<br>
<a href="RM_H5.html">H5</a>&nbsp;&nbsp;
<a href="RM_H5A.html">H5A</a>&nbsp;&nbsp;
<a href="RM_H5D.html">H5D</a>&nbsp;&nbsp;
<a href="RM_H5E.html">H5E</a>&nbsp;&nbsp;
<a href="RM_H5F.html">H5F</a>&nbsp;&nbsp;
<a href="RM_H5G.html">H5G</a>&nbsp;&nbsp;
<a href="RM_H5I.html">H5I</a>&nbsp;&nbsp;
<a href="RM_H5P.html">H5P</a>&nbsp;&nbsp;
<br>
<a href="RM_H5R.html">H5R</a>&nbsp;&nbsp;
<a href="RM_H5S.html">H5S</a>&nbsp;&nbsp;
<a href="RM_H5T.html">H5T</a>&nbsp;&nbsp;
H5Z&nbsp;&nbsp;
<a href="Tools.html">Tools</a>&nbsp;&nbsp;
<a href="PredefDTypes.html">Datatypes</a>&nbsp;&nbsp;
</td></tr>
</table>
</center>
<hr>
<address>
<a href="mailto:hdfhelp@ncsa.uiuc.edu">HDF Help Desk</a>
<br>
Last modified: 3 July 2002
<br>
Describes HDF5 Release 1.5, Unreleased Development Branch
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