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11fe00ea05
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'
116 lines
2.7 KiB
C
Executable File
116 lines
2.7 KiB
C
Executable File
/*********************************************************************
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* Copyright 1993, UCAR/Unidata
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* See netcdf/COPYRIGHT file for copying and redistribution conditions.
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* Derived from poco library from Boost Software: see nccpoco/SourceLicense file.
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*********************************************************************/
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#include "config.h"
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#include <stdlib.h>
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#include <string.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include "netcdf.h"
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#include "ncpoco.h"
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/**************************************************/
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#ifdef _WIN32
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extern struct NCPAPI ncp_win32_api;
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#else
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extern struct NCPAPI ncp_unix_api;
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#endif
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/**************************************************/
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/* Creates a SharedLib object. */
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EXTERNL int
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ncpsharedlibnew(NCPSharedLib** libp)
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{
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int ret = NC_NOERR;
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NCPSharedLib* lib;
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lib = (NCPSharedLib*)calloc(1,sizeof(NCPSharedLib));
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if(lib == 0)
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{ret = NC_ENOMEM; goto done;}
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/* fill in the api */
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#ifdef _WIN32
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lib->api = ncp_win32_api;
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#else
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lib->api = ncp_unix_api;
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#endif
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ret = lib->api.init(lib);
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if(ret == NC_NOERR && libp)
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*libp = lib;
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done:
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return ret;
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}
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/* free this shared library */
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EXTERNL int
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ncpsharedlibfree(NCPSharedLib* lib)
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{
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int ret = NC_NOERR;
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if(lib == NULL) return NC_NOERR;
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ret = lib->api.unload(lib);
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ret = lib->api.reclaim(lib);
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/* reclaim common stuff */
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nullfree(lib->path);
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free(lib);
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return ret;
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}
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/*
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Loads a shared library from the given path using specified flags.
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Returns error if a library has already been loaded or cannot be loaded.
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*/
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EXTERNL int
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ncpload(NCPSharedLib* lib, const char* path, int flags)
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{
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if(lib == NULL || path == NULL) return NC_EINVAL;
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return lib->api.load(lib,path,flags);
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}
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EXTERNL int
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ncpunload(NCPSharedLib* lib) /* Unloads a shared library. */
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{
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if(lib == NULL) return NC_EINVAL;
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return lib->api.unload(lib);
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}
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EXTERNL int
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ncpisloaded(NCPSharedLib* lib) /* Returns 1 iff a library has been loaded. */
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{
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if(lib == NULL) return 0;
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return lib->api.isloaded(lib);
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}
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/* Returns the address of the symbol with the given name.
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For functions, this is the entry point of the function.
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Return error if the symbol does not exist
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*/
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EXTERNL void*
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ncpgetsymbol(NCPSharedLib* lib,const char* name)
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{
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if(lib == NULL) return NULL;
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return lib->api.getsymbol(lib,name);
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}
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/* Returns the path of the library, as specified in
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a call to load()
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*/
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EXTERNL const char*
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ncpgetpath(NCPSharedLib* lib)
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{
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if(lib == NULL) return NULL;
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return lib->api.getpath(lib);
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}
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/* Returns the last err msg. */
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EXTERNL const char*
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ncpgeterrmsg(NCPSharedLib* lib)
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{
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if(lib == NULL) return NULL;
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return (lib->err.msg[0] == '\0' ? NULL : lib->err.msg);
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}
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