mi_page.c
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:5k
- /* 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"
- /* Fetch a key-page in memory */
- uchar *_mi_fetch_keypage(register MI_INFO *info, MI_KEYDEF *keyinfo,
- my_off_t page, int level,
- uchar *buff, int return_buffer)
- {
- uchar *tmp;
- uint page_size;
- DBUG_ENTER("_mi_fetch_keypage");
- DBUG_PRINT("enter",("page: %ld",page));
- tmp=(uchar*) key_cache_read(info->s->key_cache,
- info->s->kfile, page, level, (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;
- DBUG_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));
- DBUG_DUMP("page", (char*) tmp, keyinfo->block_length);
- info->last_keypage = HA_OFFSET_ERROR;
- my_errno = HA_ERR_CRASHED;
- tmp = 0;
- }
- DBUG_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, int level, uchar *buff)
- {
- reg3 uint length;
- DBUG_ENTER("_mi_write_keypage");
- #ifndef FAST /* Safety check */
- if (page < info->s->base.keystart ||
- page+keyinfo->block_length > info->state->key_file_length ||
- (page & (MI_MIN_KEY_BLOCK_LENGTH-1)))
- {
- DBUG_PRINT("error",("Trying to write inside key status region: key_start: %lu length: %lu page: %lu",
- (long) info->s->base.keystart,
- (long) info->state->key_file_length,
- (long) page));
- my_errno=EINVAL;
- DBUG_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
- DBUG_RETURN((key_cache_write(info->s->key_cache,
- info->s->kfile,page, level, (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,
- int level)
- {
- my_off_t old_link;
- char buff[8];
- DBUG_ENTER("_mi_dispose");
- DBUG_PRINT("enter",("pos: %ld", (long) pos));
- old_link=info->s->state.key_del[keyinfo->block_size];
- info->s->state.key_del[keyinfo->block_size]=pos;
- mi_sizestore(buff,old_link);
- info->s->state.changed|= STATE_NOT_SORTED_PAGES;
- DBUG_RETURN(key_cache_write(info->s->key_cache,
- info->s->kfile, pos , level, 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, int level)
- {
- 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->key_cache,
- info->s->kfile, pos, level,
- 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);
- }
- info->s->state.changed|= STATE_NOT_SORTED_PAGES;
- DBUG_PRINT("exit",("Pos: %ld",(long) pos));
- DBUG_RETURN(pos);
- } /* _mi_new */