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
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Copyright by The HDF Group. *
* Copyright by the Board of Trustees of the University of Illinois. *
* All rights reserved. *
* *
* This file is part of HDF5. The full HDF5 copyright notice, including *
* terms governing use, modification, and redistribution, is contained in *
* the files COPYING and Copyright.html. COPYING can be found at the root *
* of the source code distribution tree; Copyright.html can be found at the *
* root level of an installed copy of the electronic HDF5 document set and *
* is linked from the top-level documents page. It can also be found at *
* http://hdfgroup.org/HDF5/doc/Copyright.html. If you do not have *
* access to either file, you may request a copy from help@hdfgroup.org. *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*
* Programmer: Raymond Lu<slu@ncsa.uiuc.edu>
* Jan 3, 2003
*/
#define H5Z_PACKAGE /*suppress error about including H5Zpkg */
#include "H5private.h" /* Generic Functions */
#include "H5Eprivate.h" /* Error handling */
#include "H5Fprivate.h" /* File access */
#include "H5MMprivate.h" /* Memory management */
#include "H5Zpkg.h" /* Data filters */
#ifdef H5_HAVE_FILTER_FLETCHER32
/* Local function prototypes */
static size_t H5Z_filter_fletcher32 (unsigned flags, size_t cd_nelmts,
const unsigned cd_values[], size_t nbytes, size_t *buf_size, void **buf);
/* This message derives from H5Z */
const H5Z_class2_t H5Z_FLETCHER32[1] = {{
H5Z_CLASS_T_VERS, /* H5Z_class_t version */
H5Z_FILTER_FLETCHER32, /* Filter id number */
1, /* encoder_present flag (set to true) */
1, /* decoder_present flag (set to true) */
"fletcher32", /* Filter name for debugging */
NULL, /* The "can apply" callback */
NULL, /* The "set local" callback */
H5Z_filter_fletcher32, /* The actual filter function */
}};
#define FLETCHER_LEN 4
/*-------------------------------------------------------------------------
* Function: H5Z_filter_fletcher32
*
* Purpose: Implement an I/O filter of Fletcher32 Checksum
*
* Return: Success: Size of buffer filtered
* Failure: 0
*
* Programmer: Raymond Lu
* Jan 3, 2003
*
* Modifications:
* Raymond Lu
* July 8, 2005
* There was a bug in the calculating code of the Fletcher32
* checksum in the library before v1.6.3. The checksum
* value wasn't consistent between big-endian and little-endian
* systems. This bug was fixed in Release 1.6.3. However,
* after fixing the bug, the checksum value is no longer the
* same as before on little-endian system. We'll check both
* the correct checksum and the wrong checksum to be consistent
* with Release 1.6.2 and before.
*-------------------------------------------------------------------------
*/
/* ARGSUSED */
static size_t
H5Z_filter_fletcher32 (unsigned flags, size_t UNUSED cd_nelmts, const unsigned UNUSED cd_values[],
size_t nbytes, size_t *buf_size, void **buf)
{
void *outbuf = NULL; /* Pointer to new buffer */
unsigned char *src = (unsigned char*)(*buf);
uint32_t fletcher; /* Checksum value */
uint32_t reversed_fletcher; /* Possible wrong checksum value */
uint8_t c[4];
uint8_t tmp;
size_t ret_value; /* Return value */
FUNC_ENTER_NOAPI(0)
HDassert(sizeof(uint32_t)>=4);
if (flags & H5Z_FLAG_REVERSE) { /* Read */
/* Do checksum if it's enabled for read; otherwise skip it
* to save performance. */
if (!(flags & H5Z_FLAG_SKIP_EDC)) {
unsigned char *tmp_src; /* Pointer to checksum in buffer */
size_t src_nbytes = nbytes; /* Original number of bytes */
uint32_t stored_fletcher; /* Stored checksum value */
/* Get the stored checksum */
src_nbytes -= FLETCHER_LEN;
tmp_src=src+src_nbytes;
UINT32DECODE(tmp_src, stored_fletcher);
/* Compute checksum (can't fail) */
fletcher = H5_checksum_fletcher32(src, src_nbytes);
/* The reversed checksum. There was a bug in the calculating code of
* the Fletcher32 checksum in the library before v1.6.3. The checksum
* value wasn't consistent between big-endian and little-endian systems.
* This bug was fixed in Release 1.6.3. However, after fixing the bug,
* the checksum value is no longer the same as before on little-endian
* system. We'll check both the correct checksum and the wrong
* checksum to be consistent with Release 1.6.2 and before.
*/
HDmemcpy(c, &fletcher, (size_t)4);
tmp = c[1];
c[1] = c[0];
c[0] = tmp;
tmp = c[3];
c[3] = c[2];
c[2] = tmp;
HDmemcpy(&reversed_fletcher, c, (size_t)4);
/* Verify computed checksum matches stored checksum */
if(stored_fletcher != fletcher && stored_fletcher != reversed_fletcher)
HGOTO_ERROR(H5E_STORAGE, H5E_READERROR, 0, "data error detected by Fletcher32 checksum")
}
/* Set return values */
/* (Re-use the input buffer, just note that the size is smaller by the size of the checksum) */
ret_value = nbytes-FLETCHER_LEN;
} else { /* Write */
unsigned char *dst; /* Temporary pointer to destination buffer */
/* Compute checksum (can't fail) */
fletcher = H5_checksum_fletcher32(src, nbytes);
if (NULL==(dst=outbuf=H5MM_malloc(nbytes+FLETCHER_LEN)))
HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, 0, "unable to allocate Fletcher32 checksum destination buffer")
/* Copy raw data */
HDmemcpy((void*)dst, (void*)(*buf), nbytes);
/* Append checksum to raw data for storage */
dst += nbytes;
UINT32ENCODE(dst, fletcher);
/* Free input buffer */
H5MM_xfree(*buf);
/* Set return values */
*buf_size = nbytes + FLETCHER_LEN;
*buf = outbuf;
outbuf = NULL;
ret_value = *buf_size;
}
done:
if(outbuf)
H5MM_xfree(outbuf);
FUNC_LEAVE_NOAPI(ret_value)
}
#endif /* H5_HAVE_FILTER_FLETCHER32 */
|
