1/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
2
3 This program is free software; you can redistribute it and/or modify
4 it under the terms of the GNU General Public License as published by
5 the Free Software Foundation; version 2 of the License.
6
7 This program is distributed in the hope that it will be useful,
8 but WITHOUT ANY WARRANTY; without even the implied warranty of
9 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 GNU General Public License for more details.
11
12 You should have received a copy of the GNU General Public License
13 along with this program; if not, write to the Free Software
14 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA */
15
16/* Calculate a checksum for a row */
17
18#include "myisamdef.h"
19
20ha_checksum mi_checksum(MI_INFO *info, const uchar *buf)
21{
22 ha_checksum crc=0;
23 const uchar *record= buf;
24 MI_COLUMNDEF *column= info->s->rec;
25 MI_COLUMNDEF *column_end= column+ info->s->base.fields;
26 my_bool skip_null_bits= MY_TEST(info->s->options & HA_OPTION_NULL_FIELDS);
27
28 for ( ; column != column_end ; buf+= column++->length)
29 {
30 const uchar *pos;
31 ulong length;
32
33 if ((record[column->null_pos] & column->null_bit) &&
34 skip_null_bits)
35 continue; /* Null field */
36
37 switch (column->type) {
38 case FIELD_BLOB:
39 {
40 length=_mi_calc_blob_length(column->length-
41 portable_sizeof_char_ptr,
42 buf);
43 memcpy((void*) &pos, buf+column->length - portable_sizeof_char_ptr,
44 sizeof(char*));
45 break;
46 }
47 case FIELD_VARCHAR:
48 {
49 uint pack_length= HA_VARCHAR_PACKLENGTH(column->length-1);
50 if (pack_length == 1)
51 length= (ulong) *(uchar*) buf;
52 else
53 length= uint2korr(buf);
54 pos= buf+pack_length;
55 break;
56 }
57 default:
58 length=column->length;
59 pos=buf;
60 break;
61 }
62 crc=my_checksum(crc, pos ? pos : (uchar*) "", length);
63 }
64 return crc;
65}
66
67
68ha_checksum mi_static_checksum(MI_INFO *info, const uchar *pos)
69{
70 return my_checksum(0, pos, info->s->base.reclength);
71}
72