00001 /* Copyright (C) 2000-2002, 2004 MySQL AB 00002 00003 This program is free software; you can redistribute it and/or modify 00004 it under the terms of the GNU General Public License as published by 00005 the Free Software Foundation; version 2 of the License. 00006 00007 This program is distributed in the hope that it will be useful, 00008 but WITHOUT ANY WARRANTY; without even the implied warranty of 00009 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00010 GNU General Public License for more details. 00011 00012 You should have received a copy of the GNU General Public License 00013 along with this program; if not, write to the Free Software 00014 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ 00015 00016 /* Read a record with random-access. The position to the record must 00017 get by MI_INFO. The next record can be read with pos= MI_POS_ERROR */ 00018 00019 00020 #include "myisam_priv.h" 00021 00022 using namespace drizzled; 00023 00024 /* 00025 Read a row based on position. 00026 If filepos= HA_OFFSET_ERROR then read next row 00027 Return values 00028 Returns one of following values: 00029 0 = Ok. 00030 HA_ERR_RECORD_DELETED = Record is deleted. 00031 HA_ERR_END_OF_FILE = EOF. 00032 */ 00033 00034 int mi_rrnd(MI_INFO *info, unsigned char *buf, register internal::my_off_t filepos) 00035 { 00036 bool skip_deleted_blocks; 00037 00038 skip_deleted_blocks=0; 00039 00040 if (filepos == HA_OFFSET_ERROR) 00041 { 00042 skip_deleted_blocks=1; 00043 if (info->lastpos == HA_OFFSET_ERROR) /* First read ? */ 00044 filepos= info->s->pack.header_length; /* Read first record */ 00045 else 00046 filepos= info->nextpos; 00047 } 00048 00049 if (info->once_flags & RRND_PRESERVE_LASTINX) 00050 info->once_flags&= ~RRND_PRESERVE_LASTINX; 00051 else 00052 info->lastinx= -1; /* Can't forward or backward */ 00053 /* Init all but update-flag */ 00054 info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED); 00055 00056 if (info->opt_flag & WRITE_CACHE_USED && flush_io_cache(&info->rec_cache)) 00057 return(errno); 00058 00059 return ((*info->s->read_rnd)(info,buf,filepos,skip_deleted_blocks)); 00060 }