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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 */
/* The hash functions used for saveing keys */
#include "heapdef.h"
#include <m_ctype.h>
/* Search after a record based on a key */
/* Sets info->current_ptr to found record */
/* next_flag: Search=0, next=1, prev =2, same =3 */
byte *_hp_search(HP_INFO *info, HP_KEYDEF *keyinfo, const byte *key,
uint nextflag)
{
reg1 HASH_INFO *pos,*prev_ptr;
int flag;
uint old_nextflag;
HP_SHARE *share=info->s;
DBUG_ENTER("_hp_search");
old_nextflag=nextflag;
flag=1;
prev_ptr=0;
if (share->records)
{
pos=hp_find_hash(&keyinfo->block,_hp_mask(_hp_hashnr(keyinfo,key),
share->blength,share->records));
do
{
if (!_hp_key_cmp(keyinfo,pos->ptr_to_rec,key))
{
switch (nextflag) {
case 0: /* Search after key */
DBUG_PRINT("exit",("found key at %d",pos->ptr_to_rec));
info->current_hash_ptr=pos;
DBUG_RETURN(info->current_ptr= pos->ptr_to_rec);
case 1: /* Search next */
if (pos->ptr_to_rec == info->current_ptr)
nextflag=0;
break;
case 2: /* Search previous */
if (pos->ptr_to_rec == info->current_ptr)
{
my_errno=HA_ERR_KEY_NOT_FOUND; /* If gpos == 0 */
info->current_hash_ptr=prev_ptr;
DBUG_RETURN(info->current_ptr=prev_ptr ? prev_ptr->ptr_to_rec : 0);
}
prev_ptr=pos; /* Prev. record found */
break;
case 3: /* Search same */
if (pos->ptr_to_rec == info->current_ptr)
{
info->current_hash_ptr=pos;
DBUG_RETURN(info->current_ptr);
}
}
}
if (flag)
{
flag=0; /* Reset flag */
if (hp_find_hash(&keyinfo->block,
_hp_mask(_hp_rec_hashnr(keyinfo,pos->ptr_to_rec),
share->blength,share->records)) != pos)
break; /* Wrong link */
}
}
while ((pos=pos->next_key));
}
my_errno=HA_ERR_KEY_NOT_FOUND;
if (nextflag == 2 && ! info->current_ptr)
{
/* Do a previous from end */
info->current_hash_ptr=prev_ptr;
DBUG_RETURN(info->current_ptr=prev_ptr ? prev_ptr->ptr_to_rec : 0);
}
if (old_nextflag && nextflag)
my_errno=HA_ERR_RECORD_CHANGED; /* Didn't find old record */
DBUG_PRINT("exit",("Error: %d",my_errno));
info->current_hash_ptr=0;
DBUG_RETURN((info->current_ptr= 0));
}
/*
Search next after last read; Assumes that the table hasn't changed
since last read !
*/
byte *_hp_search_next(HP_INFO *info, HP_KEYDEF *keyinfo, const byte *key,
HASH_INFO *pos)
{
DBUG_ENTER("_hp_search_next");
while ((pos= pos->next_key))
{
if (!_hp_key_cmp(keyinfo,pos->ptr_to_rec,key))
{
info->current_hash_ptr=pos;
DBUG_RETURN (info->current_ptr= pos->ptr_to_rec);
}
}
my_errno=HA_ERR_KEY_NOT_FOUND;
DBUG_PRINT("exit",("Error: %d",my_errno));
info->current_hash_ptr=0;
DBUG_RETURN ((info->current_ptr= 0));
}
/* Calculate pos according to keys */
ulong _hp_mask(ulong hashnr, ulong buffmax, ulong maxlength)
{
if ((hashnr & (buffmax-1)) < maxlength) return (hashnr & (buffmax-1));
return (hashnr & ((buffmax >> 1) -1));
}
/* Change link from pos to new_link */
void _hp_movelink(HASH_INFO *pos, HASH_INFO *next_link, HASH_INFO *newlink)
{
HASH_INFO *old_link;
do
{
old_link=next_link;
}
while ((next_link=next_link->next_key) != pos);
old_link->next_key=newlink;
return;
}
/* Calc hashvalue for a key */
ulong _hp_hashnr(register HP_KEYDEF *keydef, register const byte *key)
{
register ulong nr=1, nr2=4;
HP_KEYSEG *seg,*endseg;
uchar *pos;
for (seg=keydef->seg,endseg=seg+keydef->keysegs ; seg < endseg ; seg++)
{
if (seg->type == HA_KEYTYPE_TEXT)
{
for (pos=(uchar*) key,key+=seg->length ; pos < (uchar*) key ; pos++)
{
nr^=(ulong) ((((uint) nr & 63)+nr2)*((uint) my_sort_order[(uint) *pos]))+ (nr << 8);
nr2+=3;
}
}
else
{
for (pos=(uchar*) key,key+=seg->length ; pos < (uchar*) key ; pos++)
{
nr^=(ulong) ((((uint) nr & 63)+nr2)*((uint) *pos))+ (nr << 8);
nr2+=3;
}
}
}
return((ulong) nr);
}
/* Calc hashvalue for a key in a record */
ulong _hp_rec_hashnr(register HP_KEYDEF *keydef, register const byte *rec)
{
register ulong nr=1, nr2=4;
HP_KEYSEG *seg,*endseg;
uchar *pos,*end;
for (seg=keydef->seg,endseg=seg+keydef->keysegs ; seg < endseg ; seg++)
{
if (seg->type == HA_KEYTYPE_TEXT)
{
for (pos=(uchar*) rec+seg->start,end=pos+seg->length ; pos < end ; pos++)
{
nr^=(ulong) ((((uint) nr & 63)+nr2)*((uint) my_sort_order[(uint) *pos]))+ (nr << 8);
nr2+=3;
}
}
else
{
for (pos=(uchar*) rec+seg->start,end=pos+seg->length ; pos < end ; pos++)
{
nr^=(ulong) ((((uint) nr & 63)+nr2)*((uint) *pos))+ (nr << 8);
nr2+=3;
}
}
}
return((ulong) nr);
}
/* Compare keys for two records. Returns 0 if they are identical */
int _hp_rec_key_cmp(HP_KEYDEF *keydef, const byte *rec1, const byte *rec2)
{
HP_KEYSEG *seg,*endseg;
for (seg=keydef->seg,endseg=seg+keydef->keysegs ; seg < endseg ; seg++)
{
if (seg->type == HA_KEYTYPE_TEXT)
{
if (my_sortcmp(rec1+seg->start,rec2+seg->start,seg->length))
return 1;
}
else
{
if (bcmp(rec1+seg->start,rec2+seg->start,seg->length))
return 1;
}
}
return 0;
}
/* Compare a key in a record to a hole key */
int _hp_key_cmp(HP_KEYDEF *keydef, const byte *rec, const byte *key)
{
HP_KEYSEG *seg,*endseg;
for (seg=keydef->seg,endseg=seg+keydef->keysegs ; seg < endseg ; seg++)
{
if (seg->type == HA_KEYTYPE_TEXT)
{
if (my_sortcmp(rec+seg->start,key,seg->length))
return 1;
}
else
{
if (bcmp(rec+seg->start,key,seg->length))
return 1;
}
key+=seg->length;
}
return 0;
}
/* Copy a key from a record to a keybuffer */
void _hp_make_key(HP_KEYDEF *keydef, byte *key, const byte *rec)
{
HP_KEYSEG *seg,*endseg;
for (seg=keydef->seg,endseg=seg+keydef->keysegs ; seg < endseg ; seg++)
{
memcpy(key,rec+seg->start,(size_t) seg->length);
key+=seg->length;
}
}
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