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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'
84 lines
2.7 KiB
C
84 lines
2.7 KiB
C
/*********************************************************************
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* Copyright 2018, UCAR/Unidata
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* See netcdf/COPYRIGHT file for copying and redistribution conditions.
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* $Id$
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* $Header$
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*********************************************************************/
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/*
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* In order to use any of the netcdf_XXX.h files, it is necessary
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* to include netcdf.h followed by any netcdf_XXX.h files.
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* Various things (like EXTERNL) are defined in netcdf.h
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* to make them available for use by the netcdf_XXX.h files.
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*/
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#ifndef NCAUX_H
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#define NCAUX_H
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#define NCAUX_ALIGN_C 0
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#define NCAUX_ALIGN_UNIFORM 1
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#if defined(__cplusplus)
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extern "C" {
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#endif
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/**
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Reclaim the output tree of data from a call
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to e.g. nc_get_vara or the input to e.g. nc_put_vara.
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This recursively walks the top-level instances to
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reclaim any nested data such as vlen or strings or such.
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Assumes it is passed a pointer to count instances of xtype.
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Reclaims any nested data.
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WARNING: does not reclaim the top-level memory because
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we do not know how it was allocated.
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Should work for any netcdf format.
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*/
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EXTERNL int ncaux_reclaim_data(int ncid, int xtype, void* memory, size_t count);
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EXTERNL int ncaux_begin_compound(int ncid, const char *name, int alignmode, void** tag);
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EXTERNL int ncaux_end_compound(void* tag, nc_type* typeid);
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EXTERNL int ncaux_abort_compound(void* tag);
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EXTERNL int ncaux_add_field(void* tag, const char *name, nc_type field_type,
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int ndims, const int* dimsizes);
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/* Takes any type */
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EXTERNL size_t ncaux_type_alignment(int xtype, int ncid);
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/* Takes type classes only */
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EXTERNL size_t ncaux_class_alignment(int ncclass);
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/**************************************************/
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/* Capture the id and parameters for a filter
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using the HDF5 unsigned int format
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*/
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typedef struct NC_H5_Filterspec {
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unsigned int filterid; /**< ID for arbitrary filter. */
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size_t nparams; /**< nparams for arbitrary filter. */
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unsigned int* params; /**< Params for arbitrary filter. */
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} NC_H5_Filterspec;
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EXTERNL int ncaux_h5filterspec_parse(const char* txt, unsigned int* idp, size_t* nparamsp, unsigned int** paramsp);
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EXTERNL int ncaux_h5filterspec_parselist(const char* txt0, int* formatp, size_t* nspecsp, struct NC_H5_Filterspec*** vectorp);
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EXTERNL int ncaux_h5filterspec_parse_parameter(const char* txt, size_t* nuiparamsp, unsigned int* uiparams);
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EXTERNL void ncaux_h5filterspec_free(struct NC_H5_Filterspec* f);
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EXTERNL void ncaux_h5filterspec_fix8(unsigned char* mem, int decode);
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/* Wrappers to export selected functions from libnetcdf */
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EXTERNL int ncaux_readfile(const char* filename, size_t* sizep, void** content);
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EXTERNL int ncaux_writefile(const char* filename, size_t size, void* content);
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#if defined(__cplusplus)
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}
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#endif
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#endif /*NCAUX_H*/
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