1 /* macros useful in interpreting size-related values in struct stat.
2 Copyright (C) 1989, 1991-2013 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 Macros defined by this file (s is an rvalue of type struct stat):
19 DEV_BSIZE: The device blocksize. But use ST_NBLOCKSIZE instead.
20 ST_BLKSIZE(s): Preferred (in the sense of best performance) I/O blocksize
21 for the file, in bytes.
22 ST_NBLOCKS(s): Number of blocks in the file, including indirect blocks.
23 ST_NBLOCKSIZE: Size of blocks used when calculating ST_NBLOCKS.
28 /* sys/param.h may define DEV_BSIZE */
30 # include <sys/param.h>
34 /* Get or fake the disk device blocksize.
35 Usually defined by sys/param.h (if at all). */
36 #if !defined DEV_BSIZE && defined BSIZE
37 # define DEV_BSIZE BSIZE
39 #if !defined DEV_BSIZE && defined BBSIZE /* SGI sys/param.h */
40 # define DEV_BSIZE BBSIZE
43 # define DEV_BSIZE 4096
48 /* Extract or fake data from a 'struct stat'.
49 ST_BLKSIZE: Preferred I/O blocksize for the file, in bytes.
50 ST_NBLOCKS: Number of blocks in the file, including indirect blocks.
51 ST_NBLOCKSIZE: Size of blocks used when calculating ST_NBLOCKS. */
52 #ifndef HAVE_STRUCT_STAT_ST_BLOCKS
53 # define ST_BLKSIZE(statbuf) DEV_BSIZE
54 /* coreutils' fileblocks.c also uses BSIZE. */
55 # if defined _POSIX_SOURCE || !defined BSIZE
56 # define ST_NBLOCKS(statbuf) \
57 ((statbuf).st_size / ST_NBLOCKSIZE + ((statbuf).st_size % ST_NBLOCKSIZE != 0))
59 /* This definition calls st_blocks, which is in the fileblocks module. */
60 # define ST_NBLOCKS(statbuf) \
61 (S_ISREG ((statbuf).st_mode) || S_ISDIR ((statbuf).st_mode) ? \
62 st_blocks ((statbuf).st_size) : 0)
65 /* Some systems, like Sequents, return st_blksize of 0 on pipes.
66 Also, when running 'rsh hpux11-system cat any-file', cat would
67 determine that the output stream had an st_blksize of 2147421096.
68 Conversely st_blksize can be 2 GiB (or maybe even larger) with XFS
69 on 64-bit hosts. Somewhat arbitrarily, limit the "optimal" block
70 size to SIZE_MAX / 8 + 1. (Dividing SIZE_MAX by only 4 wouldn't
71 suffice, since "cat" sometimes multiplies the result by 4.) If
72 anyone knows of a system for which this limit is too small, please
73 report it as a bug in this code. */
74 # define ST_BLKSIZE(statbuf) ((0 < (statbuf).st_blksize \
75 && (statbuf).st_blksize <= ((size_t)-1) / 8 + 1) \
76 ? (statbuf).st_blksize : DEV_BSIZE)
77 # if defined hpux || defined __hpux__ || defined __hpux
78 /* HP-UX counts st_blocks in 1024-byte units.
79 This loses when mixing HP-UX and BSD file systems with NFS. */
80 # define ST_NBLOCKSIZE 1024
82 # if defined _AIX && defined _I386
83 /* AIX PS/2 counts st_blocks in 4K units. */
84 # define ST_NBLOCKSIZE (4 * 1024)
87 # define ST_NBLOCKS(statbuf) \
88 (S_ISREG ((statbuf).st_mode) || S_ISDIR ((statbuf).st_mode) \
89 ? (statbuf).st_blocks * ST_BLKSIZE (statbuf) / ST_NBLOCKSIZE : 0)
96 # define ST_NBLOCKS(statbuf) ((statbuf).st_blocks)
101 # define ST_NBLOCKSIZE S_BLKSIZE
103 # define ST_NBLOCKSIZE 512
107 #endif /* STAT_SIZE_H */