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Diffstat (limited to 'storage/myisam/mi_checksum.c')
-rw-r--r--storage/myisam/mi_checksum.c65
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);
+}