/* 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 */ #include "mymrgdef.h" /* Read previous row with the same key as previous read */ int myrg_rprev(MYRG_INFO *info, byte *buf, int inx) { MYRG_TABLE *table; MI_INFO *mi; byte *key_buff; uint pack_key_length; int err; /* at first, do rnext for the table found before */ err=mi_rprev(info->current_table->table,NULL,inx); if (err == HA_ERR_END_OF_FILE) { queue_remove(&(info->by_key),0); if (!info->by_key.elements) return HA_ERR_END_OF_FILE; } else if (err) return err; else { /* Found here, adding to queue */ queue_top(&(info->by_key))=(byte *)(info->current_table); queue_replaced(&(info->by_key)); } /* next, let's finish myrg_rkey's initial scan */ table=info->last_used_table+1; if (table < info->end_table) { mi=info->last_used_table->table; key_buff=(byte*) mi->lastkey+mi->s->base.max_key_length; pack_key_length=mi->last_rkey_length; for (; table < info->end_table ; table++) { mi=table->table; err=_mi_rkey(mi,NULL,inx,key_buff,pack_key_length, HA_READ_KEY_OR_PREV,FALSE); info->last_used_table=table; if (err == HA_ERR_KEY_NOT_FOUND) continue; if (err) return err; /* Found here, adding to queue */ queue_insert(&(info->by_key),(byte *)table); } } /* now, mymerge's read_prev is as simple as one queue_top */ mi=(info->current_table=(MYRG_TABLE *)queue_top(&(info->by_key)))->table; return mi_rrnd(mi,buf,mi->lastpos); }