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/* 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 Street, Fifth Floor, Boston, MA 02110-1301, USA */
/* Calculate a checksum for a row */
#include "myisamdef.h"
ha_checksum mi_checksum(MI_INFO *info, const uchar *buf)
{
ha_checksum crc=0;
const uchar *record= buf;
MI_COLUMNDEF *column= info->s->rec;
MI_COLUMNDEF *column_end= column+ info->s->base.fields;
my_bool skip_null_bits= test(info->s->options & HA_OPTION_NULL_FIELDS);
for ( ; column != column_end ; buf+= column++->length)
{
const uchar *pos;
ulong length;
if ((record[column->null_pos] & column->null_bit) &&
skip_null_bits)
continue; /* Null field */
switch (column->type) {
case FIELD_BLOB:
{
length=_mi_calc_blob_length(column->length-
portable_sizeof_char_ptr,
buf);
memcpy(&pos, buf+column->length - portable_sizeof_char_ptr,
sizeof(char*));
break;
}
case FIELD_VARCHAR:
{
uint pack_length= HA_VARCHAR_PACKLENGTH(column->length-1);
if (pack_length == 1)
length= (ulong) *(uchar*) buf;
else
length= uint2korr(buf);
pos= buf+pack_length;
break;
}
default:
length=column->length;
pos=buf;
break;
}
crc=my_checksum(crc, pos ? pos : (uchar*) "", length);
}
return crc;
}
ha_checksum mi_static_checksum(MI_INFO *info, const uchar *pos)
{
return my_checksum(0, pos, info->s->base.reclength);
}
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