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Filter support has three goals: 1. Use the existing HDF5 filter implementations, 2. Allow filter metadata to be stored in the NumCodecs metadata format used by Zarr, 3. Allow filters to be used even when HDF5 is disabled Detailed usage directions are define in docs/filters.md. For now, the existing filter API is left in place. So filters are defined using ''nc_def_var_filter'' using the HDF5 style where the id and parameters are unsigned integers. This is a big change since filters affect many parts of the code. In the following, the terms "compressor" and "filter" and "codec" are generally used synonomously. ### Filter-Related Changes: * In order to support dynamic loading of shared filter libraries, a new library was added in the libncpoco directory; it helps to isolate dynamic loading across multiple platforms. * Provide a json parsing library for use by plugins; this is created by merging libdispatch/ncjson.c with include/ncjson.h. * Add a new _Codecs attribute to allow clients to see what codecs are being used; let ncdump -s print it out. * Provide special headers to help support compilation of HDF5 filters when HDF5 is not enabled: netcdf_filter_hdf5_build.h and netcdf_filter_build.h. * Add a number of new test to test the new nczarr filters. * Let ncgen parse _Codecs attribute, although it is ignored. ### Plugin directory changes: * Add support for the Blosc compressor; this is essential because it is the most common compressor used in Zarr datasets. This also necessitated adding a CMake FindBlosc.cmake file * Add NCZarr support for the big-four filters provided by HDF5: shuffle, fletcher32, deflate (zlib), and szip * Add a Codec defaulter (see docs/filters.md) for the big four filters. * Make plugins work with windows by properly adding __declspec declaration. ### Misc. Non-Filter Changes * Replace most uses of USE_NETCDF4 (deprecated) with USE_HDF5. * Improve support for caching * More fixes for path conversion code * Fix misc. memory leaks * Add new utility -- ncdump/ncpathcvt -- that does more or less the same thing as cygpath. * Add a number of new test to test the non-filter fixes. * Update the parsers * Convert most instances of '#ifdef _MSC_VER' to '#ifdef _WIN32'
61 lines
1.3 KiB
C
Executable File
61 lines
1.3 KiB
C
Executable File
/*
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* Dynamically loaded filter plugin for HDF5 blosc filter.
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*
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* Author: Kiyoshi Masui <kiyo@physics.ubc.ca>
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* Created: 2014
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*
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*
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* Header file
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* -----------
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*
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* This provides dynamically loaded HDF5 filter functionality (introduced
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* in HDF5-1.8.11, May 2013) to the blosc HDF5 filter.
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*
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* Usage: compile as a shared library and install either to the default
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* search location for HDF5 filter plugins (on Linux
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* /usr/local/hdf5/lib/plugin) or to a location pointed to by the
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* HDF5_PLUGIN_PATH environment variable.
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*
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*/
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#ifndef H5ZBLOSC_H
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#define H5ZBLOSC_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include "netcdf_filter_build.h"
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#include "blosc.h"
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/* Filter revision number, starting at 1 */
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/* #define FILTER_BLOSC_VERSION 1 */
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#define FILTER_BLOSC_VERSION 2 /* multiple compressors since Blosc 1.3 */
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/* Filter ID registered with the HDF Group */
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#define FILTER_BLOSC 32001
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#ifdef _MSC_VER
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#ifdef DLL_EXPORT /* define when building the library */
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#define DECLSPEC __declspec(dllexport)
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#else
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#define DECLSPEC __declspec(dllimport)
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#endif
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#else
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#define DECLSPEC extern
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#endif
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/* HDF5 Plugin API */
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DECLSPEC H5PL_type_t H5PLget_plugin_type(void);
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DECLSPEC const void* H5PLget_plugin_info(void);
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/* NCZarr API */
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DECLSPEC const void* NCZ_get_plugin_info(void);
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#ifdef __cplusplus
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}
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#endif
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#endif /*H5ZBLOSC_H*/
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