rkey.c
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:2k
- /* 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 */
- /* L{ser p} basen av en isam_nyckel */
- #include "isamdef.h"
- /* Read a record using key */
- /* Ordinary search_flag is 0 ; Give error if no record with key */
- int nisam_rkey(N_INFO *info, byte *buf, int inx, const byte *key, uint key_len, enum ha_rkey_function search_flag)
- {
- uchar *key_buff;
- ISAM_SHARE *share=info->s;
- DBUG_ENTER("nisam_rkey");
- DBUG_PRINT("enter",("base: %lx inx: %d search_flag: %d",
- info,inx,search_flag));
- if ((inx = _nisam_check_index(info,inx)) < 0)
- DBUG_RETURN(-1);
- info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
- if (key_len >= (share->keyinfo[inx].base.keylength - share->rec_reflength)
- && !(info->s->keyinfo[inx].base.flag & HA_SPACE_PACK_USED))
- key_len=USE_HOLE_KEY;
- key_buff=info->lastkey+info->s->base.max_key_length;
- key_len=_nisam_pack_key(info,(uint) inx,key_buff,(uchar*) key,key_len);
- DBUG_EXECUTE("key",_nisam_print_key(DBUG_FILE,share->keyinfo[inx].seg,
- (uchar*) key););
- #ifndef NO_LOCKING
- if (_nisam_readinfo(info,F_RDLCK,1))
- goto err;
- #endif
- VOID(_nisam_search(info,info->s->keyinfo+inx,key_buff,key_len,
- nisam_read_vec[search_flag],info->s->state.key_root[inx]));
- if ((*info->read_record)(info,info->lastpos,buf) >= 0)
- {
- info->update|= HA_STATE_AKTIV; /* Record is read */
- DBUG_RETURN(0);
- }
- info->lastpos = NI_POS_ERROR; /* Didn't find key */
- VOID(_nisam_move_key(info->s->keyinfo+inx,info->lastkey,key_buff));
- if (search_flag == HA_READ_AFTER_KEY)
- info->update|=HA_STATE_NEXT_FOUND; /* Previous gives last row */
- err:
- DBUG_RETURN(-1);
- } /* nisam_rkey */