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/* Copyright (C) 2000 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; either version 2 of the License, or
(at your option) any later version.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* Calculate a checksum for a row */
#include "myisamdef.h"
ha_checksum mi_checksum(MI_INFO *info, const byte *buf)
{
uint i;
ha_checksum crc=0;
MI_COLUMNDEF *rec=info->s->rec;
for (i=info->s->base.fields ; i-- ; buf+=(rec++)->length)
{
const byte *pos;
const byte *end;
switch (rec->type) {
case FIELD_BLOB:
{
ulong length=_mi_calc_blob_length(rec->length-
mi_portable_sizeof_char_ptr,
buf);
memcpy((char*) &pos, buf+rec->length- mi_portable_sizeof_char_ptr,
sizeof(char*));
end=pos+length;
break;
}
case FIELD_VARCHAR:
{
uint length;
length=uint2korr(buf);
pos=buf+2; end=pos+length;
break;
}
default:
pos=buf; end=buf+rec->length;
break;
}
for ( ; pos != end ; pos++)
crc=((crc << 8) + *((uchar*) pos)) + (crc >> (8*sizeof(ha_checksum)-8));
}
return crc;
}
ha_checksum mi_static_checksum(MI_INFO *info, const byte *pos)
{
ha_checksum crc;
const byte *end=pos+info->s->base.reclength;
for (crc=0; pos != end; pos++)
crc=((crc << 8) + *((uchar*) pos)) + (crc >> (8*sizeof(ha_checksum)-8));
return crc;
}
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