diff options
Diffstat (limited to 'storage/myisam/mi_checksum.c')
-rw-r--r-- | storage/myisam/mi_checksum.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/storage/myisam/mi_checksum.c b/storage/myisam/mi_checksum.c new file mode 100644 index 00000000000..33a51068fb0 --- /dev/null +++ b/storage/myisam/mi_checksum.c @@ -0,0 +1,65 @@ +/* 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; + ulong length; + switch (rec->type) { + case FIELD_BLOB: + { + 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*)); + break; + } + case FIELD_VARCHAR: + { + uint pack_length= HA_VARCHAR_PACKLENGTH(rec->length-1); + if (pack_length == 1) + length= (ulong) *(uchar*) buf; + else + length= uint2korr(buf); + pos= buf+pack_length; + break; + } + default: + length=rec->length; + pos=buf; + break; + } + crc=my_checksum(crc, pos ? pos : "", length); + } + return crc; +} + + +ha_checksum mi_static_checksum(MI_INFO *info, const byte *pos) +{ + return my_checksum(0, pos, info->s->base.reclength); +} |