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/* Copyright (C) 2006 MySQL AB & MySQL Finland AB & TCX DataKonsult 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 Street, Fifth Floor, Boston, MA 02110-1335 USA */
/* Calculate a checksum for a row */
#include "maria_def.h"
/**
Calculate a checksum for the record
_ma_checksum()
@param info Maria handler
@param record Record
@note
To ensure that the checksum is independent of the row format
we need to always calculate the checksum in the original field order.
@return checksum
*/
ha_checksum _ma_checksum(MARIA_HA *info, const uchar *record)
{
ha_checksum crc=0;
uint i,end;
MARIA_COLUMNDEF *base_column= info->s->columndef;
uint16 *column_nr= info->s->column_nr;
if (info->s->base.null_bytes)
crc= my_checksum(crc, record, info->s->base.null_bytes);
for (i= 0, end= info->s->base.fields ; i < end ; i++)
{
MARIA_COLUMNDEF *column= base_column + column_nr[i];
const uchar *pos;
ulong length;
if (record[column->null_pos] & column->null_bit)
continue; /* Null field */
pos= record + column->offset;
switch (column->type) {
case FIELD_BLOB:
{
uint blob_size_length= column->length- portable_sizeof_char_ptr;
length= _ma_calc_blob_length(blob_size_length, pos);
if (length)
{
memcpy((char**) &pos, pos + blob_size_length, sizeof(char*));
crc= my_checksum(crc, pos, length);
}
continue;
}
case FIELD_VARCHAR:
{
uint pack_length= column->fill_length;
if (pack_length == 1)
length= (ulong) *pos;
else
length= uint2korr(pos);
pos+= pack_length; /* Skip length information */
break;
}
default:
length= column->length;
break;
}
crc= my_checksum(crc, pos, length);
}
return crc;
}
ha_checksum _ma_static_checksum(MARIA_HA *info, const uchar *pos)
{
return my_checksum(0, pos, info->s->base.reclength);
}
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