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https://github.com/Unidata/netcdf-c.git
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d07c05b58f
re: issue https://github.com/Unidata/netcdf-c/issues/1156 Starting with HDF5 version 1.10.x, the plugin code MUST be careful when using the standard *malloc()*, *realloc()*, and *free()* function. In the event that the code is allocating, reallocating, or free'ing memory that either came from -- or will be exported to -- the calling HDF5 library, then one MUST use the corresponding HDF5 functions *H5allocate_memory()*, *H5resize_memory()*, *H5free_memory()* [5] to avoid memory failures. Additionally, if your filter code leaks memory, then the HDF5 library generates a failure something like this. ```` H5MM.c:232: H5MM_final_sanity_check: Assertion `0 == H5MM_curr_alloc_bytes_s' failed. ```` This PR modifies the code in the plugins directory to conform to these new requirements. This raises a question about the libhdf5 code where this same problem may occur. We need to scan especially nc4hdf.c to look for this problem.
105 lines
2.9 KiB
C
105 lines
2.9 KiB
C
#include <sys/types.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include <stdio.h>
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#include <hdf5.h>
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/* Older versions of the hdf library may define H5PL_type_t here */
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#include <H5PLextern.h>
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#include "xxxx.h"
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/*
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Provide a textual template (not a C++ template)
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from which one can construct a new filter.
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The filter "name is marked with "XXXX" or "xxxx"
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*/
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const H5Z_class2_t H5Z_XXXX[1] = {{
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H5Z_CLASS_T_VERS, /* H5Z_class_t version */
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(H5Z_filter_t)H5Z_FILTER_XXXX, /* Filter id number */
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1, /* encoder_present flag (set to true) */
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1, /* decoder_present flag (set to true) */
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"xxxx", /* Filter name for debugging */
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NULL, /* The "can apply" callback */
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NULL, /* The "set local" callback */
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(H5Z_func_t)H5Z_filter_xxxx, /* The actual filter function */
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}};
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/* External Discovery Functions */
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H5PL_type_t
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H5PLget_plugin_type(void)
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{
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return H5PL_TYPE_FILTER;
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}
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const void*
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H5PLget_plugin_info(void)
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{
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return H5Z_XXXX;
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}
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size_t H5Z_filter_xxxx(unsigned int flags, size_t cd_nelmts,
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const unsigned int cd_values[], size_t nbytes,
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size_t *buf_size, void **buf);
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size_t H5Z_filter_xxxx(unsigned int flags, size_t cd_nelmts,
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const unsigned int cd_values[], size_t nbytes,
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size_t *buf_size, void **buf)
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{
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char *outbuf = NULL;
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size_t outbuflen, outdatalen;
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int ret;
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if (flags & H5Z_FLAG_REVERSE) {
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/** Decompress data.
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**
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** This process is troublesome since the size of uncompressed data
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** is unknown, so the low-level interface must be used.
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** Data is decompressed to the output buffer (which is sized
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** for the average case); if it gets full, its size is doubled
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** and decompression continues. This avoids repeatedly trying to
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** decompress the whole block, which could be really inefficient.
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**/
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char *newbuf = NULL;
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size_t newbuflen;
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} else {
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/** Compress data.
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**
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** This is quite simple, since the size of compressed data in the worst
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** case is known and it is not much bigger than the size of uncompressed
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** data. This allows us to use the simplified one-shot interface to
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** compression.
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**/
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unsigned int odatalen; /* maybe not the same size as outdatalen */
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/* Prepare the output buffer. */
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outbuflen = M; /* worst case */
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outbuf = H5allocate_memory(outbuflen,0);
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if (outbuf == NULL) {
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fprintf(stderr, "memory allocation failed for xxxx compression\n");
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goto cleanupAndFail;
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}
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/* Compress data. */
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}
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/* Always replace the input buffer with the output buffer. */
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H5free_memory(*buf);
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*buf = outbuf;
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*buf_size = outbuflen;
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return outdatalen;
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cleanupAndFail:
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if (outbuf)
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H5free_memory(outbuf);
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return 0;
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}
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