hp_write.c
上传用户:tsgydb
上传日期:2007-04-14
资源大小:10674k
文件大小:7k
- /* 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 */
- /* Write a record to heap-databas */
- #include "heapdef.h"
- #ifdef __WIN__
- #include <fcntl.h>
- #endif
- #define LOWFIND 1
- #define LOWUSED 2
- #define HIGHFIND 4
- #define HIGHUSED 8
- static byte *next_free_record_pos(HP_SHARE *info);
- static HASH_INFO *_hp_find_free_hash(HP_SHARE *info, HP_BLOCK *block,
- ulong records);
- int heap_write(HP_INFO *info, const byte *record)
- {
- uint key;
- byte *pos;
- HP_SHARE *share=info->s;
- DBUG_ENTER("heap_write");
- #ifndef DBUG_OFF
- if (info->mode && O_RDONLY)
- {
- DBUG_RETURN(my_errno=EACCES);
- }
- #endif
- if (!(pos=next_free_record_pos(share)))
- DBUG_RETURN(my_errno);
- share->changed=1;
- for (key=0 ; key < share->keys ; key++)
- {
- if (_hp_write_key(share,share->keydef+key,record,pos))
- goto err;
- }
- memcpy(pos,record,(size_t) share->reclength);
- pos[share->reclength]=1; /* Mark record as not deleted */
- if (++share->records == share->blength)
- share->blength+= share->blength;
- info->current_ptr=pos;
- info->current_hash_ptr=0;
- info->update|=HA_STATE_AKTIV;
- DBUG_RETURN(0);
- err:
- info->errkey= key;
- do
- {
- if (_hp_delete_key(info,share->keydef+key,record,pos,0))
- break;
- } while (key-- > 0);
- share->deleted++;
- *((byte**) pos)=share->del_link;
- share->del_link=pos;
- pos[share->reclength]=0; /* Record deleted */
- DBUG_RETURN(my_errno);
- } /* heap_write */
- /* Find where to place new record */
- static byte *next_free_record_pos(HP_SHARE *info)
- {
- int block_pos;
- byte *pos;
- ulong length;
- DBUG_ENTER("next_free_record_pos");
- if (info->del_link)
- {
- pos=info->del_link;
- info->del_link= *((byte**) pos);
- info->deleted--;
- DBUG_PRINT("exit",("Used old position: %lx",pos));
- DBUG_RETURN(pos);
- }
- if (!(block_pos=(info->records % info->block.records_in_block)))
- {
- if (info->records > info->max_records && info->max_records)
- {
- my_errno=HA_ERR_RECORD_FILE_FULL;
- DBUG_RETURN(NULL);
- }
- if (_hp_get_new_block(&info->block,&length))
- DBUG_RETURN(NULL);
- info->data_length+=length;
- }
- DBUG_PRINT("exit",("Used new position: %lx",
- (byte*) info->block.level_info[0].last_blocks+block_pos*
- info->block.recbuffer));
- DBUG_RETURN((byte*) info->block.level_info[0].last_blocks+
- block_pos*info->block.recbuffer);
- }
- /* Write a hash-key to the hash-index */
- int _hp_write_key(register HP_SHARE *info, HP_KEYDEF *keyinfo,
- const byte *record, byte *recpos)
- {
- int flag;
- ulong halfbuff,hashnr,first_index;
- byte *ptr_to_rec,*ptr_to_rec2;
- HASH_INFO *empty,*gpos,*gpos2,*pos;
- DBUG_ENTER("hp_write_key");
- LINT_INIT(gpos); LINT_INIT(gpos2);
- LINT_INIT(ptr_to_rec); LINT_INIT(ptr_to_rec2);
- flag=0;
- if (!(empty= _hp_find_free_hash(info,&keyinfo->block,info->records)))
- DBUG_RETURN(-1); /* No more memory */
- halfbuff= (long) info->blength >> 1;
- pos= hp_find_hash(&keyinfo->block,(first_index=info->records-halfbuff));
- if (pos != empty) /* If some records */
- {
- do
- {
- hashnr=_hp_rec_hashnr(keyinfo,pos->ptr_to_rec);
- if (flag == 0) /* First loop; Check if ok */
- if (_hp_mask(hashnr,info->blength,info->records) != first_index)
- break;
- if (!(hashnr & halfbuff))
- { /* Key will not move */
- if (!(flag & LOWFIND))
- {
- if (flag & HIGHFIND)
- {
- flag=LOWFIND | HIGHFIND;
- /* key shall be moved to the current empty position */
- gpos=empty;
- ptr_to_rec=pos->ptr_to_rec;
- empty=pos; /* This place is now free */
- }
- else
- {
- flag=LOWFIND | LOWUSED; /* key isn't changed */
- gpos=pos;
- ptr_to_rec=pos->ptr_to_rec;
- }
- }
- else
- {
- if (!(flag & LOWUSED))
- {
- /* Change link of previous LOW-key */
- gpos->ptr_to_rec=ptr_to_rec;
- gpos->next_key=pos;
- flag= (flag & HIGHFIND) | (LOWFIND | LOWUSED);
- }
- gpos=pos;
- ptr_to_rec=pos->ptr_to_rec;
- }
- }
- else
- { /* key will be moved */
- if (!(flag & HIGHFIND))
- {
- flag= (flag & LOWFIND) | HIGHFIND;
- /* key shall be moved to the last (empty) position */
- gpos2 = empty; empty=pos;
- ptr_to_rec2=pos->ptr_to_rec;
- }
- else
- {
- if (!(flag & HIGHUSED))
- {
- /* Change link of previous hash-key and save */
- gpos2->ptr_to_rec=ptr_to_rec2;
- gpos2->next_key=pos;
- flag= (flag & LOWFIND) | (HIGHFIND | HIGHUSED);
- }
- gpos2=pos;
- ptr_to_rec2=pos->ptr_to_rec;
- }
- }
- }
- while ((pos=pos->next_key));
- if ((flag & (LOWFIND | LOWUSED)) == LOWFIND)
- {
- gpos->ptr_to_rec=ptr_to_rec;
- gpos->next_key=0;
- }
- if ((flag & (HIGHFIND | HIGHUSED)) == HIGHFIND)
- {
- gpos2->ptr_to_rec=ptr_to_rec2;
- gpos2->next_key=0;
- }
- }
- /* Check if we are at the empty position */
- pos=hp_find_hash(&keyinfo->block,_hp_mask(_hp_rec_hashnr(keyinfo,record),
- info->blength,info->records+1));
- if (pos == empty)
- {
- pos->ptr_to_rec=recpos;
- pos->next_key=0;
- }
- else
- {
- /* Check if more records in same hash-nr family */
- empty[0]=pos[0];
- gpos=hp_find_hash(&keyinfo->block,
- _hp_mask(_hp_rec_hashnr(keyinfo,pos->ptr_to_rec),
- info->blength,info->records+1));
- if (pos == gpos)
- {
- pos->ptr_to_rec=recpos;
- pos->next_key=empty;
- }
- else
- {
- pos->ptr_to_rec=recpos;
- pos->next_key=0;
- _hp_movelink(pos,gpos,empty);
- }
- /* Check if dupplicated keys */
- if ((keyinfo->flag & HA_NOSAME) && pos == gpos)
- {
- pos=empty;
- do
- {
- if (! _hp_rec_key_cmp(keyinfo,record,pos->ptr_to_rec))
- {
- DBUG_RETURN(my_errno=HA_ERR_FOUND_DUPP_KEY);
- }
- } while ((pos=pos->next_key));
- }
- }
- DBUG_RETURN(0);
- }
- /* Returns ptr to block, and allocates block if neaded */
- static HASH_INFO *_hp_find_free_hash(HP_SHARE *info,
- HP_BLOCK *block, ulong records)
- {
- uint block_pos;
- ulong length;
- if (records < block->last_allocated)
- return hp_find_hash(block,records);
- if (!(block_pos=(records % block->records_in_block)))
- {
- if (_hp_get_new_block(block,&length))
- return(NULL);
- info->index_length+=length;
- }
- block->last_allocated=records+1;
- return((HASH_INFO*) ((byte*) block->level_info[0].last_blocks+
- block_pos*block->recbuffer));
- }