mirror of
https://github.com/MariaDB/server.git
synced 2025-11-04 04:46:15 +01:00
117 lines
3.5 KiB
C
117 lines
3.5 KiB
C
/* 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);
|
|
}
|