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-rw-r--r--storage/maria/ma_checksum.c89
1 files changed, 89 insertions, 0 deletions
diff --git a/storage/maria/ma_checksum.c b/storage/maria/ma_checksum.c
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+++ b/storage/maria/ma_checksum.c
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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);
+}