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by brian
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/* Copyright (C) 2000-2001, 2003-2004 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/* Calculate a checksum for a row */
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#include "myisamdef.h" |
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ha_checksum mi_checksum(MI_INFO *info, const uchar *buf) |
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{
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uint i; |
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ha_checksum crc=0; |
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MI_COLUMNDEF *rec=info->s->rec; |
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for (i=info->s->base.fields ; i-- ; buf+=(rec++)->length) |
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{
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const uchar *pos; |
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ulong length; |
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switch (rec->type) { |
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case FIELD_BLOB: |
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{
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length=_mi_calc_blob_length(rec->length- |
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portable_sizeof_char_ptr, |
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buf); |
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memcpy((char*) &pos, buf+rec->length- portable_sizeof_char_ptr, |
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sizeof(char*)); |
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break; |
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}
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case FIELD_VARCHAR: |
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{
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uint pack_length= HA_VARCHAR_PACKLENGTH(rec->length-1); |
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if (pack_length == 1) |
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length= (ulong) *(uchar*) buf; |
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else
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length= uint2korr(buf); |
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pos= buf+pack_length; |
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break; |
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}
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default: |
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length=rec->length; |
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pos=buf; |
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break; |
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}
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crc=my_checksum(crc, pos ? pos : (uchar*) "", length); |
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}
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return crc; |
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}
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ha_checksum mi_static_checksum(MI_INFO *info, const uchar *pos) |
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{
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return my_checksum(0, pos, info->s->base.reclength); |
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}
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