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94 lines
3.0 KiB
HTML
94 lines
3.0 KiB
HTML
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<html>
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<head><title>
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HDF5/H5Z Draft API Specification
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</title></head>
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<body>
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<center>
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<h1>H5Z: Compression Interface</h1>
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</center>
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<h2>Compression API Functions</h2>
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This function enable the user to configure a new compression
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method for the local environment.
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<table border=0>
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<tr><td valign=top>
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<ul>
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<li><a href="#Compression-Register">H5Zregister</a>
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</ul>
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</td><td> </td><td valign=top>
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<ul>
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</ul>
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</td></tr>
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</table>
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<p>
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HDF5 supports compression of raw data by compression methods
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built into the library or defined by an application.
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A compression method is associated with a dataset when the dataset is
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created and is applied independently to each storage chunk of the dataset.
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The dataset must use the <code>H5D_CHUNKED</code> storage layout.
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<p>
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The HDF5 library does not support compression for contiguous datasets
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because of the difficulty of implementing random access for partial I/O.
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Compact dataset compression is not supported because it would not produce
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significant results.
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<p>
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See <a href="../UG/Compression.html"><cite>Compression</cite></a> in the
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<cite>HDF5 User's Guide</cite> for further information.
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<hr>
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<dl>
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<dt><strong>Name:</strong> <a name="Compression-Register">H5Zregister</a>
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<dt><strong>Signature:</strong>
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<dd><em>herr_t</em> <code>H5Zregister</code>(<em>H5Z_method_t</em> <code>method</code>,
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<em>const char *</em><code>name</code>,
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<em>H5Z_func_t</em><code>cfunc</code>,
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<em>H5Z_func_t</em> <code>ufunc</code>
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)
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<dt><strong>Purpose:</strong>
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<dd> Registers new compression and uncompression functions for a
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method specified by a method number.
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<dt><strong>Description:</strong>
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<dd><code>H5Zregister</code> registers new compression and uncompression
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functions for a method specified by a method number, <code>method</code>.
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<code>name</code> is used for debugging and may be the null pointer.
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Either or both of <code>cfunc</code> (the compression function) and
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<code>ufunc</code> (the uncompression method) may be null pointers.
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<p>
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The statistics associated with a method number are not reset
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by this function; they accumulate over the life of the library.
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<dt><strong>Parameters:</strong>
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<dl>
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<dt><em>H5Z_method_t</em> <code>method</code>
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<dd>Number specifying compression method.
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<dt><em>const char *</em><code>name</code>
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<dd>Name associated with the method number.
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<dt><em>H5Z_func_t</em> <code>cfunc</code>
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<dd>Compression method.
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<dt><em>H5Z_func_t</em> <code>ufunc</code>
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<dd>Uncompression method.
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</dl>
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<dt><strong>Returns:</strong>
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<dd>Returns SUCCEED (0) if successful;
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otherwise FAIL (-1).
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</dl>
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<hr>
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<address>
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<a href="mailto:fbaker@ncsa.uiuc.edu">Frank Baker</a>
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<br>
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<a href="mailto:h5docs@ncsa.uiuc.edu">HDF5 Documentation</a>
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<br>
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Last modified: 8 July 1998
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</body>
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</html>
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