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71 lines
2.1 KiB
C
71 lines
2.1 KiB
C
/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
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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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 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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ha_checksum crc=0;
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const uchar *record= buf;
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MI_COLUMNDEF *column= info->s->rec;
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MI_COLUMNDEF *column_end= column+ info->s->base.fields;
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my_bool skip_null_bits= MY_TEST(info->s->options & HA_OPTION_NULL_FIELDS);
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for ( ; column != column_end ; buf+= column++->length)
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{
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const uchar *pos;
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ulong length;
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if ((record[column->null_pos] & column->null_bit) &&
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skip_null_bits)
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continue; /* Null field */
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switch (column->type) {
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case FIELD_BLOB:
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{
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length=_mi_calc_blob_length(column->length-
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portable_sizeof_char_ptr,
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buf);
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memcpy((void*) &pos, buf+column->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(column->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=column->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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