1/* Copyright (C) 2006 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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 02111-1301 USA */
15
16/* Calculate a checksum for a row */
17
18#include "maria_def.h"
19
20/**
21 Calculate a checksum for the record
22
23 _ma_checksum()
24 @param info Maria handler
25 @param record Record
26
27 @note
28 To ensure that the checksum is independent of the row format
29 we need to always calculate the checksum in the original field order.
30
31 @return checksum
32*/
33
34ha_checksum _ma_checksum(MARIA_HA *info, const uchar *record)
35{
36 ha_checksum crc=0;
37 uint i,end;
38 MARIA_COLUMNDEF *base_column= info->s->columndef;
39 uint16 *column_nr= info->s->column_nr;
40
41 if (info->s->base.null_bytes)
42 crc= my_checksum(crc, record, info->s->base.null_bytes);
43
44 for (i= 0, end= info->s->base.fields ; i < end ; i++)
45 {
46 MARIA_COLUMNDEF *column= base_column + column_nr[i];
47 const uchar *pos;
48 ulong length;
49
50 if (record[column->null_pos] & column->null_bit)
51 continue; /* Null field */
52
53 pos= record + column->offset;
54 switch (column->type) {
55 case FIELD_BLOB:
56 {
57 uint blob_size_length= column->length- portable_sizeof_char_ptr;
58 length= _ma_calc_blob_length(blob_size_length, pos);
59 if (length)
60 {
61 memcpy((char**) &pos, pos + blob_size_length, sizeof(char*));
62 crc= my_checksum(crc, pos, length);
63 }
64 continue;
65 }
66 case FIELD_VARCHAR:
67 {
68 uint pack_length= column->fill_length;
69 if (pack_length == 1)
70 length= (ulong) *pos;
71 else
72 length= uint2korr(pos);
73 pos+= pack_length; /* Skip length information */
74 break;
75 }
76 default:
77 length= column->length;
78 break;
79 }
80 crc= my_checksum(crc, pos, length);
81 }
82 return crc;
83}
84
85
86ha_checksum _ma_static_checksum(MARIA_HA *info, const uchar *pos)
87{
88 return my_checksum(0, pos, info->s->base.reclength);
89}
90