lib/stat-size.h

   1 /* Yield size-related values in struct stat.
   2    Copyright (C) 1989, 1991-2024 Free Software Foundation, Inc.
   3
   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.
   8
   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.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #ifndef STAT_SIZE_H
  18 #define STAT_SIZE_H
  19
  20 /* This file uses HAVE_SYS_PARAM_H, HAVE_STRUCT_STAT_ST_BLOCKS.  */
  21 #if !_GL_CONFIG_H_INCLUDED
  22  #error "Please include config.h first."
  23 #endif
  24
  25 /* sys/param.h may define DEV_BSIZE */
  26 #if HAVE_SYS_PARAM_H
  27 # include <sys/param.h>
  28 #endif
  29
  30 /* The device blocksize, or a faked version thereof.
  31    But use ST_NBLOCKSIZE instead.
  32    Usually defined by sys/param.h (if at all).  */
  33 #if !defined DEV_BSIZE && defined BSIZE
  34 # define DEV_BSIZE BSIZE
  35 #endif
  36 #if !defined DEV_BSIZE && defined BBSIZE /* SGI sys/param.h */
  37 # define DEV_BSIZE BBSIZE
  38 #endif
  39 #ifndef DEV_BSIZE
  40 # define DEV_BSIZE 4096
  41 #endif
  42
  43 /* Extract or fake data from a struct stat *st.
  44    STP_BLKSIZE(st): Preferred performance I/O blocksize, in bytes.
  45    STP_NBLOCKS(st): Number of blocks, including indirect blocks.
  46    ST_NBLOCKSIZE: Size of blocks used when calculating ST_NBLOCKS.  */
  47 #ifndef HAVE_STRUCT_STAT_ST_BLOCKS
  48 # define STP_BLKSIZE(st) DEV_BSIZE
  49   /* coreutils' fileblocks.c also uses BSIZE.  */
  50 # if defined _POSIX_SOURCE || !defined BSIZE
  51 #  define STP_NBLOCKS(st) \
  52     ((st)->st_size / ST_NBLOCKSIZE + ((st)->st_size % ST_NBLOCKSIZE != 0))
  53 # else
  54    /* This definition calls st_blocks, which is in the fileblocks module. */
  55 #  define STP_NBLOCKS(st) \
  56     (S_ISREG ((st)->st_mode) || S_ISDIR ((st)->st_mode) \
  57      ? st_blocks ((st)->st_size) : 0)
  58 # endif
  59 #else
  60 /* When running 'rsh hpux11-system cat any-file', cat would
  61    determine that the output stream had an st_blksize of 2147421096.
  62    Conversely st_blksize can be 2 GiB (or maybe even larger) with XFS
  63    on 64-bit hosts.  Somewhat arbitrarily, limit the "optimal" block
  64    size to SIZE_MAX / 8 + 1.  (Dividing SIZE_MAX by only 4 wouldn't
  65    suffice, since "cat" sometimes multiplies the result by 4.)  If
  66    anyone knows of a system for which this limit is too small, please
  67    report it as a bug in this code.  */
  68 # define STP_BLKSIZE(st) ((0 < (st)->st_blksize \
  69                            && (st)->st_blksize <= (size_t) -1 / 8 + 1)  \
  70                           ? (st)->st_blksize : DEV_BSIZE)
  71 # if defined hpux || defined __hpux__ || defined __hpux
  72   /* HP-UX counts st_blocks in 1024-byte units.
  73      This loses when mixing HP-UX and BSD file systems with NFS.  */
  74 #  define ST_NBLOCKSIZE 1024
  75 # endif
  76 #endif
  77
  78 #ifndef STP_NBLOCKS
  79 # define STP_NBLOCKS(st) ((st)->st_blocks)
  80 #endif
  81
  82 #ifndef ST_NBLOCKSIZE
  83 # ifdef S_BLKSIZE
  84 #  define ST_NBLOCKSIZE S_BLKSIZE
  85 # else
  86 #  define ST_NBLOCKSIZE 512
  87 # endif
  88 #endif
  89
  90 /* Preferred blocksize and number of blocks for a struct stat object.  */
  91 #define ST_BLKSIZE(statbuf) STP_BLKSIZE (&(statbuf))
  92 #define ST_NBLOCKS(statbuf) STP_NBLOCKS (&(statbuf))
  93
  94 #endif /* STAT_SIZE_H */