mariadb/myisam/mi_page.c
bk@work.mysql.com f4c589ff6c Import changeset
2000-07-31 21:29:14 +02:00

144 lines
4.2 KiB
C

/* 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 */
/* Read and write key blocks */
#include "myisamdef.h"
#ifdef __WIN__
#include <errno.h>
#endif
/* Fetch a key-page in memory */
uchar *_mi_fetch_keypage(register MI_INFO *info, MI_KEYDEF *keyinfo,
my_off_t page, uchar *buff, int return_buffer)
{
uchar *tmp;
uint page_size;
tmp=(uchar*) key_cache_read(info->s->kfile,page,(byte*) buff,
(uint) keyinfo->block_length,
(uint) keyinfo->block_length,
return_buffer);
if (tmp == info->buff)
info->buff_used=1;
else if (!tmp)
{
DBUG_PRINT("error",("Got errno: %d from key_cache_read",my_errno));
info->last_keypage=HA_OFFSET_ERROR;
my_errno=HA_ERR_CRASHED;
return 0;
}
info->last_keypage=page;
page_size=mi_getint(tmp);
if (page_size < 4 || page_size > keyinfo->block_length)
{
DBUG_PRINT("error",("page %lu had wrong page length: %u",
(ulong) page, page_size));
info->last_keypage = HA_OFFSET_ERROR;
my_errno = HA_ERR_CRASHED;
tmp = 0;
}
return tmp;
} /* _mi_fetch_keypage */
/* Write a key-page on disk */
int _mi_write_keypage(register MI_INFO *info, register MI_KEYDEF *keyinfo,
my_off_t page, uchar *buff)
{
reg3 uint length;
#ifndef FAST /* Safety check */
if (page < info->s->base.keystart ||
page+keyinfo->block_length > info->state->key_file_length ||
page & (myisam_block_size-1))
{
DBUG_PRINT("error",("Trying to write outside key region: %lu",
(long) page));
my_errno=EINVAL;
return(-1);
}
DBUG_PRINT("page",("write page at: %lu",(long) page,buff));
DBUG_DUMP("buff",(byte*) buff,mi_getint(buff));
#endif
if ((length=keyinfo->block_length) > IO_SIZE*2 &&
info->state->key_file_length != page+length)
length= ((mi_getint(buff)+IO_SIZE-1) & (uint) ~(IO_SIZE-1));
#ifdef HAVE_purify
{
length=mi_getint(buff);
bzero((byte*) buff+length,keyinfo->block_length-length);
length=keyinfo->block_length;
}
#endif
return (key_cache_write(info->s->kfile,page,(byte*) buff,length,
(uint) keyinfo->block_length,
(int) ((info->lock_type != F_UNLCK) ||
info->s->delay_key_write)));
} /* mi_write_keypage */
/* Remove page from disk */
int _mi_dispose(register MI_INFO *info, MI_KEYDEF *keyinfo, my_off_t pos)
{
my_off_t old_link;
char buff[8];
DBUG_ENTER("_mi_dispose");
old_link=info->s->state.key_del[keyinfo->block_size];
info->s->state.key_del[keyinfo->block_size]=pos;
mi_sizestore(buff,old_link);
DBUG_RETURN(key_cache_write(info->s->kfile,pos,buff,
sizeof(buff),
(uint) keyinfo->block_length,
(int) (info->lock_type != F_UNLCK)));
} /* _mi_dispose */
/* Make new page on disk */
my_off_t _mi_new(register MI_INFO *info, MI_KEYDEF *keyinfo)
{
my_off_t pos;
char buff[8];
DBUG_ENTER("_mi_new");
if ((pos=info->s->state.key_del[keyinfo->block_size]) == HA_OFFSET_ERROR)
{
if (info->state->key_file_length >=
info->s->base.max_key_file_length - keyinfo->block_length)
{
my_errno=HA_ERR_INDEX_FILE_FULL;
DBUG_RETURN(HA_OFFSET_ERROR);
}
pos=info->state->key_file_length;
info->state->key_file_length+= keyinfo->block_length;
}
else
{
if (!key_cache_read(info->s->kfile,pos,
buff,
(uint) sizeof(buff),
(uint) keyinfo->block_length,0))
pos= HA_OFFSET_ERROR;
else
info->s->state.key_del[keyinfo->block_size]=mi_sizekorr(buff);
}
DBUG_PRINT("exit",("Pos: %d",pos));
DBUG_RETURN(pos);
} /* _mi_new */