1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
|
#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 = H5allocate_memory(outbuflen,0);
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. */
H5free_memory(*buf);
*buf = outbuf;
*buf_size = outbuflen;
return outdatalen;
cleanupAndFail:
if (outbuf)
H5free_memory(outbuf);
return 0;
}
|
