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aeb3ac2809
re: https://github.com/Unidata/netcdf-c/issues/1836 Revert the internal filter code to simplify it. From the user's point of view, the only visible changes should be: 1. The functions that convert text to filter specs have had their signature reverted and have been moved to netcdf_aux.h 2. Some filter API functions now return NC_ENOFILTER when inquiry is made about some filter. Internally,the dispatch table has been modified to get rid of the filter_actions entry and associated complex structures. It has been replaced with inq_var_filter_ids and inq_var_filter_info entries and the dispatch table version has been bumped to 3. Corresponding NOOP and NOTNC4 functions were added to libdispatch/dnotnc4.c. Also, the filter_action entries in dispatch tables were replaced for all dispatch code bases (HDF5, DAP2, etc). This should only impact UDF users. In the process, it became clear that the form of the filters field in NC_VAR_INFO_T was format dependent, so I converted it to be of type void* and pushed its management into the various dispatch code bases. Specifically libhdf5 and libnczarr now manage the filters field in their own way. The auxilliary functions for parsing textual filter specifications were moved to netcdf_aux.h and were renamed to the following: * ncaux_h5filterspec_parse * ncaux_h5filterspec_parselist * ncaux_h5filterspec_free * ncaux_h5filter_fix8 Misc. Other Changes: 1. Document NUG/filters.md updated to reflect the changes above. 2. All the old data types (structs and enums) used by filter_actions actions were deleted. The exception is the NC_H5_Filterspec because it is needed by ncaux_h5filterspec_parselist. 3. Clientside filters were removed -- another enhancement for which no-one ever asked. 4. The ability to remove filters was itself removed. 5. Some functionality needed by nczarr was moved from libhdf5 to libsrc4 e.g. nc4_find_default_chunksizes 6. All the filterx code was removed 7. ncfilter.h and nc4filter.c no longer used Misc. Unrelated Changes: 1. The nczarr_test makefile clean was leaving some directories; so add clean-local to take care of them.
67 lines
1.4 KiB
C
67 lines
1.4 KiB
C
/*
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* Copyright 2018, University Corporation for Atmospheric Research
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* See netcdf/COPYRIGHT file for copying and redistribution conditions.
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*/
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#include "config.h"
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#include <hdf5.h>
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/*
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Common utilities related to filters.
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Taken from libdispatch/dfilters.c.
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*/
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#ifdef WORDS_BIGENDIAN
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/* Byte swap an 8-byte integer in place */
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static void
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byteswap8(unsigned char* mem)
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{
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unsigned char c;
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c = mem[0];
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mem[0] = mem[7];
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mem[7] = c;
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c = mem[1];
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mem[1] = mem[6];
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mem[6] = c;
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c = mem[2];
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mem[2] = mem[5];
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mem[5] = c;
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c = mem[3];
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mem[3] = mem[4];
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mem[4] = c;
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}
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/* Byte swap an 8-byte integer in place */
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static void
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byteswap4(unsigned char* mem)
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{
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unsigned char c;
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c = mem[0];
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mem[0] = mem[3];
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mem[3] = c;
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c = mem[1];
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mem[1] = mem[2];
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mem[2] = c;
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}
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#endif /*WORDS_BIGENDIAN*/
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void
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NC_h5filterspec_fix8(void* mem0, int decode)
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{
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#ifdef WORDS_BIGENDIAN
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unsigned char* mem = mem0;
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if(decode) { /* Apply inverse of the encode case */
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byteswap4(mem); /* step 1: byte-swap each piece */
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byteswap4(mem+4);
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byteswap8(mem); /* step 2: convert to little endian format */
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} else { /* encode */
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byteswap8(mem); /* step 1: convert to little endian format */
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byteswap4(mem); /* step 2: byte-swap each piece */
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byteswap4(mem+4);
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}
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#else /* Little endian */
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/* No action is necessary */
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#endif
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}
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