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
|
/* Copyright (C) 2000-2001, 2003-2004 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
/* Calculate a checksum for a row */
#include "myisam_priv.h"
#include <zlib.h>
using namespace drizzled;
/*
Calculate a long checksum for a memoryblock.
SYNOPSIS
my_checksum()
crc start value for crc
pos pointer to memory block
length length of the block
*/
static ha_checksum my_checksum(ha_checksum crc, const unsigned char *pos, size_t length)
{
return ha_checksum(crc32((uint32_t)crc, pos, uInt(length)));
}
ha_checksum mi_checksum(MI_INFO *info, const unsigned char *buf)
{
uint32_t i;
ha_checksum crc=0;
MI_COLUMNDEF *rec=info->s->rec;
for (i=info->s->base.fields ; i-- ; buf+=(rec++)->length)
{
const unsigned char *pos;
ulong length;
switch (rec->type) {
case FIELD_BLOB:
{
length=_mi_calc_blob_length(rec->length-
portable_sizeof_char_ptr,
buf);
memcpy(&pos, buf+rec->length - portable_sizeof_char_ptr, sizeof(char*));
break;
}
case FIELD_VARCHAR:
{
uint32_t pack_length= ha_varchar_packlength(rec->length-1);
if (pack_length == 1)
length= (ulong) *(unsigned char*) buf;
else
length= uint2korr(buf);
pos= buf+pack_length;
break;
}
default:
length=rec->length;
pos=buf;
break;
}
crc=my_checksum(crc, pos ? pos : (unsigned char*) "", length);
}
return crc;
}
ha_checksum mi_static_checksum(MI_INFO *info, const unsigned char *pos)
{
return my_checksum(0, pos, info->s->base.reclength);
}
|