1
/* Copyright (C) 2000-2004 MySQL AB
3
This program is free software; you can redistribute it and/or modify
4
it under the terms of the GNU General Public License as published by
5
the Free Software Foundation; version 2 of the License.
7
This program is distributed in the hope that it will be useful,
8
but WITHOUT ANY WARRANTY; without even the implied warranty of
9
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10
GNU General Public License for more details.
12
You should have received a copy of the GNU General Public License
13
along with this program; if not, write to the Free Software
14
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
20
Caching of files with only does (sequential) read or writes of fixed-
21
length records. A read isn't allowed to go over file-length. A read is ok
22
if it ends at file-length and next read can try to read after file-length
23
(and get a EOF-error).
24
Possibly use of asyncronic io.
25
macros for read and writes for faster io.
26
Used instead of FILE when reading or writing whole files.
27
This will make mf_rec_cache obsolete.
28
One can change info->pos_in_file to a higher value to skip bytes in file if
29
also info->rc_pos is set to info->rc_end.
30
If called through open_cached_file(), then the temporary file will
31
only be created if a write exeeds the file buffer or if one calls
34
#include <drizzled/server_includes.h>
35
#include <drizzled/session.h>
38
Read buffered from the net.
41
1 if can't read requested characters
45
int _my_b_net_read(register IO_CACHE *info, unsigned char *Buffer, size_t)
48
NET *net= &(current_session)->net;
50
if (!info->end_of_file)
51
return(1); /* because my_b_get (no _) takes 1 byte at a time */
52
read_length=my_net_read(net);
53
if (read_length == packet_error)
60
info->end_of_file= 0; /* End of file from client */
63
/* to set up stuff for my_b_get (no _) */
64
info->read_end = (info->read_pos = (unsigned char*) net->read_pos) + read_length;
65
Buffer[0] = info->read_pos[0]; /* length is always 1 */
68
info->request_pos is used by log_loaded_block() to know the size
70
info->pos_in_file is used by log_loaded_block() too.
72
info->pos_in_file+= read_length;
73
info->request_pos=info->read_pos;