diff options
Diffstat (limited to 'heap/hp_delete.c')
| -rw-r--r-- | heap/hp_delete.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/heap/hp_delete.c b/heap/hp_delete.c new file mode 100644 index 00000000000..a6e77fe5f27 --- /dev/null +++ b/heap/hp_delete.c @@ -0,0 +1,151 @@ +/* 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 */ + +/* remove current record in heap-database */ + +#include "heapdef.h" + +int heap_delete(HP_INFO *info, const byte *record) +{ + uint key; + byte *pos; + HP_SHARE *share=info->s; + DBUG_ENTER("heap_delete"); + DBUG_PRINT("enter",("info: %lx record: %lx",info,record)); + + test_active(info); + + if (info->opt_flag & READ_CHECK_USED && _hp_rectest(info,record)) + DBUG_RETURN(my_errno); /* Record changed */ + share->changed=1; + + if ( --(share->records) < share->blength >> 1) share->blength>>=1; + pos=info->current_ptr; + + for (key=0 ; key < share->keys ; key++) + { + if (_hp_delete_key(info,share->keydef+key,record,pos, + key == (uint) info->lastinx)) + goto err; + } + + info->update=HA_STATE_DELETED; + *((byte**) pos)=share->del_link; + share->del_link=pos; + pos[share->reclength]=0; /* Record deleted */ + share->deleted++; + info->current_hash_ptr=0; + DBUG_RETURN(0); + err: + if( ++(share->records) == share->blength) share->blength+= share->blength; + DBUG_RETURN(my_errno); +} + + /* Remove one key from hash-table */ + /* Flag is set if we want's to correct info->current_ptr */ + +int _hp_delete_key(HP_INFO *info, register HP_KEYDEF *keyinfo, + const byte *record, byte *recpos, int flag) +{ + ulong blength,pos2,pos_hashnr,lastpos_hashnr; + HASH_INFO *lastpos,*gpos,*pos,*pos3,*empty,*last_ptr; + HP_SHARE *share=info->s; + DBUG_ENTER("_hp_delete_key"); + + blength=share->blength; + if (share->records+1 == blength) blength+= blength; + lastpos=hp_find_hash(&keyinfo->block,share->records); + last_ptr=0; + + /* Search after record with key */ + pos= hp_find_hash(&keyinfo->block, + _hp_mask(_hp_rec_hashnr(keyinfo,record),blength, + share->records+1)); + gpos = pos3 = 0; + + while (pos->ptr_to_rec != recpos) + { + if (flag && !_hp_rec_key_cmp(keyinfo,record,pos->ptr_to_rec)) + last_ptr=pos; /* Previous same key */ + gpos=pos; + if (!(pos=pos->next_key)) + { + DBUG_RETURN(my_errno=HA_ERR_CRASHED); /* This shouldn't happend */ + } + } + + /* Remove link to record */ + + if (flag) + { + /* Save for heap_rnext/heap_rprev */ + info->current_hash_ptr=last_ptr; + info->current_ptr = last_ptr ? last_ptr->ptr_to_rec : 0; + DBUG_PRINT("info",("Corrected current_ptr to point at: %lx", + info->current_ptr)); + } + empty=pos; + if (gpos) + gpos->next_key=pos->next_key; /* unlink current ptr */ + else if (pos->next_key) + { + empty=pos->next_key; + pos->ptr_to_rec=empty->ptr_to_rec; + pos->next_key=empty->next_key; + } + + if (empty == lastpos) /* deleted last hash key */ + DBUG_RETURN (0); + + /* Move the last key (lastpos) */ + lastpos_hashnr=_hp_rec_hashnr(keyinfo,lastpos->ptr_to_rec); + /* pos is where lastpos should be */ + pos=hp_find_hash(&keyinfo->block,_hp_mask(lastpos_hashnr,share->blength, + share->records)); + if (pos == empty) /* Move to empty position. */ + { + empty[0]=lastpos[0]; + DBUG_RETURN(0); + } + pos_hashnr=_hp_rec_hashnr(keyinfo,pos->ptr_to_rec); + /* pos3 is where the pos should be */ + pos3= hp_find_hash(&keyinfo->block, + _hp_mask(pos_hashnr,share->blength,share->records)); + if (pos != pos3) + { /* pos is on wrong posit */ + empty[0]=pos[0]; /* Save it here */ + pos[0]=lastpos[0]; /* This shold be here */ + _hp_movelink(pos,pos3,empty); /* Fix link to pos */ + DBUG_RETURN(0); + } + pos2= _hp_mask(lastpos_hashnr,blength,share->records+1); + if (pos2 == _hp_mask(pos_hashnr,blength,share->records+1)) + { /* Identical key-positions */ + if (pos2 != share->records) + { + empty[0]=lastpos[0]; + _hp_movelink(lastpos,pos,empty); + DBUG_RETURN(0); + } + pos3= pos; /* Link pos->next after lastpos */ + } + else pos3= 0; /* Different positions merge */ + + empty[0]=lastpos[0]; + _hp_movelink(pos3,empty,pos->next_key); + pos->next_key=empty; + DBUG_RETURN(0); +} |