netcdf-c/plugins/H5Ztemplate.c
Dennis Heimbigner d3b309722e re: gh issue https://github.com/Unidata/netcdf-c/issues/911
I took Ed's advice and moved the plugin stuff to its own
top-level directory. This is an attempt to solve the problem of
copying files that we have experienced. In any case, it will
serve as a place to stick additional plugins.
2018-04-21 20:10:47 -06:00

105 lines
2.9 KiB
C

#include <sys/types.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <stdio.h>
#include <hdf5.h>
/* Older versions of the hdf library may define H5PL_type_t here */
#include <H5PLextern.h>
#include "xxxx.h"
/*
Provide a textual template (not a C++ template)
from which one can construct a new filter.
The filter "name is marked with "XXXX" or "xxxx"
*/
const H5Z_class2_t H5Z_XXXX[1] = {{
H5Z_CLASS_T_VERS, /* H5Z_class_t version */
(H5Z_filter_t)H5Z_FILTER_XXXX, /* Filter id number */
1, /* encoder_present flag (set to true) */
1, /* decoder_present flag (set to true) */
"xxxx", /* Filter name for debugging */
NULL, /* The "can apply" callback */
NULL, /* The "set local" callback */
(H5Z_func_t)H5Z_filter_xxxx, /* The actual filter function */
}};
/* External Discovery Functions */
H5PL_type_t
H5PLget_plugin_type(void)
{
return H5PL_TYPE_FILTER;
}
const void*
H5PLget_plugin_info(void)
{
return H5Z_XXXX;
}
size_t H5Z_filter_xxxx(unsigned int flags, size_t cd_nelmts,
const unsigned int cd_values[], size_t nbytes,
size_t *buf_size, void **buf);
size_t H5Z_filter_xxxx(unsigned int flags, size_t cd_nelmts,
const unsigned int cd_values[], size_t nbytes,
size_t *buf_size, void **buf)
{
char *outbuf = NULL;
size_t outbuflen, outdatalen;
int ret;
if (flags & H5Z_FLAG_REVERSE) {
/** Decompress data.
**
** This process is troublesome since the size of uncompressed data
** is unknown, so the low-level interface must be used.
** Data is decompressed to the output buffer (which is sized
** for the average case); if it gets full, its size is doubled
** and decompression continues. This avoids repeatedly trying to
** decompress the whole block, which could be really inefficient.
**/
char *newbuf = NULL;
size_t newbuflen;
} else {
/** Compress data.
**
** This is quite simple, since the size of compressed data in the worst
** case is known and it is not much bigger than the size of uncompressed
** data. This allows us to use the simplified one-shot interface to
** compression.
**/
unsigned int odatalen; /* maybe not the same size as outdatalen */
/* Prepare the output buffer. */
outbuflen = M; /* worst case */
outbuf = malloc(outbuflen);
if (outbuf == NULL) {
fprintf(stderr, "memory allocation failed for xxxx compression\n");
goto cleanupAndFail;
}
/* Compress data. */
}
/* Always replace the input buffer with the output buffer. */
free(*buf);
*buf = outbuf;
*buf_size = outbuflen;
return outdatalen;
cleanupAndFail:
if (outbuf)
free(outbuf);
return 0;
}