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authorserg@infomag.ape.relarn.ru <>2000-08-14 15:27:19 +0400
committerserg@infomag.ape.relarn.ru <>2000-08-14 15:27:19 +0400
commit5886090182881b29143091c9bb4d7e7b406ea5df (patch)
tree290f97643db41800f2922e6143b2a89e93d5476d /myisammrg/myrg_rprev.c
parent807460bbceceec25bf97352bc5e232c3e766d70f (diff)
downloadmariadb-git-5886090182881b29143091c9bb4d7e7b406ea5df.tar.gz
PART I: Keys support for MyMERGE tables
myisammrg/ | Makefile.am | mymrgdef.h | support for keys myrg_open.c | & myrg_queue.c | bugfixes myrg_rfirst.c | myrg_rkey.c | myrg_rlast.c | myrg_rnext.c | myrg_rprev.c | myrg_rrnd.c | include/myisammrg.h | rkey/rnext/etc prototyped sql/ | ha_myisammrg.cc | support for keys ha_myisammrg.h | myisam/ | mi_rkey.c | buf==NULL extension, _mi_rkey() mi_rnext.c | mi_rprev.c | include/queues.h | reinit_queue() - same as init_queue, but w/o malloc mysys/queues.c | PART II: Miscellaneous myisam/common_words | deleted (looks like I checked it in by mistake) some files (like acconfig.h, Makefile.am, COPYING.LIB, etc) | Change mode to -rw-r--r-- (by `chmod a-x ')
Diffstat (limited to 'myisammrg/myrg_rprev.c')
-rw-r--r--myisammrg/myrg_rprev.c76
1 files changed, 76 insertions, 0 deletions
diff --git a/myisammrg/myrg_rprev.c b/myisammrg/myrg_rprev.c
new file mode 100644
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+/* 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;
+ uchar *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=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);
+}
+
+