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-rw-r--r--heap/hp_hash.c266
1 files changed, 266 insertions, 0 deletions
diff --git a/heap/hp_hash.c b/heap/hp_hash.c
new file mode 100644
index 00000000000..28647ab7c94
--- /dev/null
+++ b/heap/hp_hash.c
@@ -0,0 +1,266 @@
+/* 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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