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-rw-r--r--storage/myisammrg/myrg_rrnd.c117
1 files changed, 117 insertions, 0 deletions
diff --git a/storage/myisammrg/myrg_rrnd.c b/storage/myisammrg/myrg_rrnd.c
new file mode 100644
index 00000000..a97f6d30
--- /dev/null
+++ b/storage/myisammrg/myrg_rrnd.c
@@ -0,0 +1,117 @@
+/* Copyright (c) 2000-2002, 2005-2007 MySQL AB
+ Use is subject to license terms
+
+ 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; version 2 of the License.
+
+ 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
+
+/*
+ Read a record with random-access. The position to the record must
+ get by myrg_info(). The next record can be read with pos= -1 */
+
+
+#include "myrg_def.h"
+
+static MYRG_TABLE *find_table(MYRG_TABLE *start,MYRG_TABLE *end,ulonglong pos);
+
+/*
+ If filepos == HA_OFFSET_ERROR, read next
+ Returns same as mi_rrnd:
+ 0 = Ok.
+ HA_ERR_RECORD_DELETED = Record is deleted.
+ HA_ERR_END_OF_FILE = EOF.
+*/
+
+int myrg_rrnd(MYRG_INFO *info,uchar *buf,ulonglong filepos)
+{
+ int error;
+ MI_INFO *isam_info;
+ DBUG_ENTER("myrg_rrnd");
+ DBUG_PRINT("info",("offset: %lu", (ulong) filepos));
+
+ if (filepos == HA_OFFSET_ERROR)
+ {
+ if (!info->current_table)
+ {
+ if (info->open_tables == info->end_table)
+ { /* No tables */
+ DBUG_RETURN(my_errno=HA_ERR_END_OF_FILE);
+ }
+ isam_info=(info->current_table=info->open_tables)->table;
+ if (info->cache_in_use)
+ mi_extra(isam_info,HA_EXTRA_CACHE,(uchar*) &info->cache_size);
+ filepos=isam_info->s->pack.header_length;
+ isam_info->lastinx= (uint) -1; /* Can't forward or backward */
+ }
+ else
+ {
+ isam_info=info->current_table->table;
+ filepos= isam_info->nextpos;
+ }
+
+ for (;;)
+ {
+ isam_info->update&= HA_STATE_CHANGED;
+ if ((error=(*isam_info->s->read_rnd)(isam_info,(uchar*) buf,
+ (my_off_t) filepos,1)) !=
+ HA_ERR_END_OF_FILE)
+ DBUG_RETURN(error);
+ if (info->cache_in_use)
+ mi_extra(info->current_table->table, HA_EXTRA_NO_CACHE,
+ (uchar*) &info->cache_size);
+ if (info->current_table+1 == info->end_table)
+ DBUG_RETURN(HA_ERR_END_OF_FILE);
+ info->current_table++;
+ info->last_used_table=info->current_table;
+ if (info->cache_in_use)
+ mi_extra(info->current_table->table, HA_EXTRA_CACHE,
+ (uchar*) &info->cache_size);
+ info->current_table->file_offset=
+ info->current_table[-1].file_offset+
+ info->current_table[-1].table->state->data_file_length;
+
+ isam_info=info->current_table->table;
+ filepos=isam_info->s->pack.header_length;
+ isam_info->lastinx= (uint) -1;
+ }
+ }
+ info->current_table=find_table(info->open_tables,
+ info->end_table-1,filepos);
+ isam_info=info->current_table->table;
+ isam_info->update&= HA_STATE_CHANGED;
+ DBUG_RETURN((*isam_info->s->read_rnd)
+ (isam_info, (uchar*) buf,
+ (my_off_t) (filepos - info->current_table->file_offset),
+ 0));
+}
+
+
+ /* Find which table to use according to file-pos */
+
+static MYRG_TABLE *find_table(MYRG_TABLE *start, MYRG_TABLE *end,
+ ulonglong pos)
+{
+ MYRG_TABLE *mid;
+ DBUG_ENTER("find_table");
+
+ while (start != end)
+ {
+ mid=start+((uint) (end-start)+1)/2;
+ if (mid->file_offset > pos)
+ end=mid-1;
+ else
+ start=mid;
+ }
+ DBUG_PRINT("info",("offset: %lu, table: %s",
+ (ulong) pos, start->table->filename));
+ DBUG_RETURN(start);
+}