mariadb/myisam/mi_cache.c
monty@hundin.mysql.fi b1cb5b6ff0 Portability fixes.
Let myisamchk generate a new checksum for compressed data.
Don't unconditionally force filenames to lower case on windows.
Update mysqltest to match 4.0 source (to get some of the new bug fixes into 3.23)
2001-08-18 10:49:00 +03:00

97 lines
3.3 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 */
/* Functions for read record cacheing with myisam */
/* Used instead of my_b_read() to allow for no-cacheed seeks */
#include "myisamdef.h"
/* Copy block from cache if it`s in it. If re_read_if_possibly is */
/* set read to cache (if after current file-position) else read to */
/* buff */
int _mi_read_cache(IO_CACHE *info, byte *buff, my_off_t pos, uint length,
int flag)
{
uint read_length,in_buff_length;
my_off_t offset;
char *in_buff_pos;
DBUG_ENTER("_mi_read_cache");
if (pos < info->pos_in_file)
{
read_length=length;
if ((my_off_t) read_length > (my_off_t) (info->pos_in_file-pos))
read_length=(uint) (info->pos_in_file-pos);
info->seek_not_done=1;
if (my_pread(info->file,buff,read_length,pos,MYF(MY_NABP)))
DBUG_RETURN(1);
if (!(length-=read_length))
DBUG_RETURN(0);
pos+=read_length;
buff+=read_length;
}
if ((offset= (my_off_t) (pos - info->pos_in_file)) <
(my_off_t) (info->rc_end - info->rc_request_pos))
{
in_buff_pos=info->rc_request_pos+(uint) offset;
in_buff_length= min(length,(uint) (info->rc_end-in_buff_pos));
memcpy(buff,info->rc_request_pos+(uint) offset,(size_t) in_buff_length);
if (!(length-=in_buff_length))
DBUG_RETURN(0);
pos+=in_buff_length;
buff+=in_buff_length;
}
else
in_buff_length=0;
if (flag & READING_NEXT)
{
if (pos != ((info)->pos_in_file +
(uint) ((info)->rc_end - (info)->rc_request_pos)))
{
info->pos_in_file=pos; /* Force start here */
info->rc_pos=info->rc_end=info->rc_request_pos; /* Everything used */
info->seek_not_done=1;
}
else
info->rc_pos=info->rc_end; /* All block used */
if (!(*info->read_function)(info,buff,length))
DBUG_RETURN(0);
if (!(flag & READING_HEADER) || info->error == -1 ||
(uint) info->error+in_buff_length < 3)
{
if (!my_errno || my_errno == -1)
my_errno=HA_ERR_WRONG_IN_RECORD;
DBUG_RETURN(1);
}
bzero(buff+info->error,MI_BLOCK_INFO_HEADER_LENGTH - in_buff_length -
(uint) info->error);
DBUG_RETURN(0);
}
info->seek_not_done=1;
if ((read_length=my_pread(info->file,buff,length,pos,MYF(0))) == length)
DBUG_RETURN(0);
if (!(flag & READING_HEADER) || (int) read_length == -1 ||
read_length+in_buff_length < 3)
{
if (!my_errno || my_errno == -1)
my_errno=HA_ERR_WRONG_IN_RECORD;
DBUG_RETURN(1);
}
bzero(buff+read_length,MI_BLOCK_INFO_HEADER_LENGTH - in_buff_length -
read_length);
DBUG_RETURN(0);
} /* _mi_read_cache */