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/* 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 */
/* Functions to handle keys and fields in forms */
#include "mysql_priv.h"
/*
** Search after with key field is. If no key starts with field test
** if field is part of some key.
**
** returns number of key. keylength is set to length of key before
** (not including) field
** Used when calculating key for NEXT_NUMBER
*/
int find_ref_key(TABLE *table,Field *field, uint *key_length)
{
reg2 int i;
reg3 KEY *key_info;
uint fieldpos;
fieldpos= field->offset();
/* Test if some key starts as fieldpos */
for (i=0, key_info=table->key_info ; i < (int) table->keys ; i++, key_info++)
{
if (key_info->key_part[0].offset == fieldpos)
{ /* Found key. Calc keylength */
*key_length=0;
return(i); /* Use this key */
}
}
/* Test if some key contains fieldpos */
for (i=0, key_info=table->key_info ; i < (int) table->keys ; i++, key_info++)
{
uint j;
KEY_PART_INFO *key_part;
*key_length=0;
for (j=0, key_part=key_info->key_part ;
j < key_info->key_parts ;
j++, key_part++)
{
if (key_part->offset == fieldpos)
return(i); /* Use this key */
*key_length+=key_part->store_length;
}
}
return(-1); /* No key is ok */
}
/* Copy a key from record to some buffer */
/* if length == 0 then copy whole key */
void key_copy(byte *key,TABLE *table,uint idx,uint key_length)
{
uint length;
KEY *key_info=table->key_info+idx;
KEY_PART_INFO *key_part;
if (key_length == 0)
key_length=key_info->key_length;
for (key_part=key_info->key_part;
(int) key_length > 0 ;
key_part++)
{
if (key_part->null_bit)
{
*key++= test(table->record[0][key_part->null_offset] &
key_part->null_bit);
key_length--;
}
if (key_part->key_part_flag & HA_BLOB_PART)
{
char *pos;
ulong blob_length=((Field_blob*) key_part->field)->get_length();
key_length-=2;
((Field_blob*) key_part->field)->get_ptr(&pos);
length=min(key_length,key_part->length);
set_if_smaller(blob_length,length);
int2store(key,(uint) blob_length);
key+=2; // Skip length info
memcpy(key,pos,blob_length);
}
else
{
length=min(key_length,key_part->length);
memcpy(key,table->record[0]+key_part->offset,(size_t) length);
}
key+=length;
key_length-=length;
}
} /* key_copy */
/* restore a key from some buffer to record */
void key_restore(TABLE *table,byte *key,uint idx,uint key_length)
{
uint length;
KEY *key_info=table->key_info+idx;
KEY_PART_INFO *key_part;
if (key_length == 0)
{
if (idx == (uint) -1)
return;
key_length=key_info->key_length;
}
for (key_part=key_info->key_part;
(int) key_length > 0 ;
key_part++)
{
if (key_part->null_bit)
{
if (*key++)
table->record[0][key_part->null_offset]|= key_part->null_bit;
else
table->record[0][key_part->null_offset]&= ~key_part->null_bit;
key_length--;
}
if (key_part->key_part_flag & HA_BLOB_PART)
{
uint blob_length=uint2korr(key);
key+=2;
key_length-=2;
((Field_blob*) key_part->field)->set_ptr((ulong) blob_length,
(char*) key);
length=key_part->length;
}
else
{
length=min(key_length,key_part->length);
memcpy(table->record[0]+key_part->offset,key,(size_t) length);
}
key+=length;
key_length-=length;
}
} /* key_restore */
/* Compare if a key has changed */
int key_cmp(TABLE *table,const byte *key,uint idx,uint key_length)
{
uint length;
KEY_PART_INFO *key_part;
for (key_part=table->key_info[idx].key_part;
(int) key_length > 0;
key_part++, key+=length, key_length-=length)
{
if (key_part->null_bit)
{
key_length--;
if (*key != test(table->record[0][key_part->null_offset] &
key_part->null_bit))
return 1;
if (*key)
{
length=key_part->store_length;
continue;
}
key++;
}
if (key_part->key_part_flag & (HA_BLOB_PART | HA_VAR_LENGTH))
{
if (key_part->field->key_cmp(key, key_part->length+ HA_KEY_BLOB_LENGTH))
return 1;
length=key_part->length+HA_KEY_BLOB_LENGTH;
}
else
{
length=min(key_length,key_part->length);
if (!(key_part->key_type & (FIELDFLAG_NUMBER+FIELDFLAG_BINARY+
FIELDFLAG_PACK)))
{
if (my_strnncoll(key_part->field->charset(),
(const uchar*) key, length,
(const uchar*) table->record[0]+key_part->offset,
length))
return 1;
}
else if (memcmp(key,table->record[0]+key_part->offset,length))
return 1;
}
}
return 0;
}
/* unpack key-fields from record to some buffer */
/* This is used to get a good error message */
void key_unpack(String *to,TABLE *table,uint idx)
{
KEY_PART_INFO *key_part,*key_part_end;
Field *field;
String tmp;
DBUG_ENTER("key_unpack");
to->length(0);
for (key_part=table->key_info[idx].key_part,key_part_end=key_part+
table->key_info[idx].key_parts ;
key_part < key_part_end;
key_part++)
{
if (to->length())
to->append('-');
if (key_part->null_bit)
{
if (table->record[0][key_part->null_offset] & key_part->null_bit)
{
to->append("NULL", 4);
continue;
}
}
if ((field=key_part->field))
{
field->val_str(&tmp);
if (key_part->length < field->pack_length())
tmp.length(min(tmp.length(),key_part->length));
to->append(tmp);
}
else
to->append("???", 3);
}
DBUG_VOID_RETURN;
}
/*
Return 1 if any field in a list is part of key or the key uses a field
that is automaticly updated (like a timestamp)
*/
bool check_if_key_used(TABLE *table, uint idx, List<Item> &fields)
{
List_iterator_fast<Item> f(fields);
KEY_PART_INFO *key_part,*key_part_end;
for (key_part=table->key_info[idx].key_part,key_part_end=key_part+
table->key_info[idx].key_parts ;
key_part < key_part_end;
key_part++)
{
Item_field *field;
if (key_part->field == table->timestamp_field)
return 1; // Can't be used for update
f.rewind();
while ((field=(Item_field*) f++))
{
if (key_part->field == field->field)
return 1;
}
}
/*
If table handler has primary key as part of the index, check that primary
key is not updated
*/
if (idx != table->primary_key && table->primary_key < MAX_KEY &&
(table->file->table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX))
return check_if_key_used(table, table->primary_key, fields);
return 0;
}
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