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stat-size.h

/* macros useful in interpreting size-related values in struct stat.
   Copyright (C) 1989, 1991-2011 Free Software Foundation, Inc.

   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 3 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, see <http://www.gnu.org/licenses/>.  */
/*
   Macros defined by this file (s is an rvalue of type struct stat):

   DEV_BSIZE:       The device blocksize.  But use ST_NBLOCKSIZE instead.
   ST_BLKSIZE(s):   Preferred (in the sense of best performance) I/O blocksize
                    for the file, in bytes.
   ST_NBLOCKS(s):   Number of blocks in the file, including indirect blocks.
   ST_NBLOCKSIZE:   Size of blocks used when calculating ST_NBLOCKS.
 */
#ifndef STAT_SIZE_H
#define STAT_SIZE_H

/* sys/param.h may define DEV_BSIZE */
#if HAVE_SYS_PARAM_H
# include <sys/param.h>
#endif


/* Much of the remainder of this file is not indented consistently
   with the above, in order to make it easier to see that the text
   is almost identical to part of the system.h header in coreutils.
*/
/* Get or fake the disk device blocksize.
   Usually defined by sys/param.h (if at all).  */
#if !defined DEV_BSIZE && defined BSIZE
# define DEV_BSIZE BSIZE
#endif
#if !defined DEV_BSIZE && defined BBSIZE /* SGI sys/param.h */
# define DEV_BSIZE BBSIZE
#endif
#ifndef DEV_BSIZE
# define DEV_BSIZE 4096
#endif



/* Extract or fake data from a `struct stat'.
   ST_BLKSIZE: Preferred I/O blocksize for the file, in bytes.
   ST_NBLOCKS: Number of blocks in the file, including indirect blocks.
   ST_NBLOCKSIZE: Size of blocks used when calculating ST_NBLOCKS.  */
#ifndef HAVE_STRUCT_STAT_ST_BLOCKS
# define ST_BLKSIZE(statbuf) DEV_BSIZE
  /* coreutils' fileblocks.c also uses BSIZE.  */
# if defined _POSIX_SOURCE || !defined BSIZE
#  define ST_NBLOCKS(statbuf) \
  ((statbuf).st_size / ST_NBLOCKSIZE + ((statbuf).st_size % ST_NBLOCKSIZE != 0))
# else
   /* This definition calls st_blocks, which is in the fileblocks module. */
#  define ST_NBLOCKS(statbuf) \
  (S_ISREG ((statbuf).st_mode) || S_ISDIR ((statbuf).st_mode) ? \
   st_blocks ((statbuf).st_size) : 0)
# endif
#else
/* Some systems, like Sequents, return st_blksize of 0 on pipes.
   Also, when running `rsh hpux11-system cat any-file', cat would
   determine that the output stream had an st_blksize of 2147421096.
   Conversely st_blksize can be 2 GiB (or maybe even larger) with XFS
   on 64-bit hosts.  Somewhat arbitrarily, limit the `optimal' block
   size to SIZE_MAX / 8 + 1.  (Dividing SIZE_MAX by only 4 wouldn't
   suffice, since "cat" sometimes multiplies the result by 4.)  If
   anyone knows of a system for which this limit is too small, please
   report it as a bug in this code.  */
# define ST_BLKSIZE(statbuf) ((0 < (statbuf).st_blksize \
                               && (statbuf).st_blksize <= ((size_t)-1) / 8 + 1) \
                              ? (statbuf).st_blksize : DEV_BSIZE)
# if defined hpux || defined __hpux__ || defined __hpux
  /* HP-UX counts st_blocks in 1024-byte units.
     This loses when mixing HP-UX and BSD file systems with NFS.  */
#  define ST_NBLOCKSIZE 1024
# else /* !hpux */
#  if defined _AIX && defined _I386
    /* AIX PS/2 counts st_blocks in 4K units.  */
#   define ST_NBLOCKSIZE (4 * 1024)
#  else
#   if defined _CRAY
#    define ST_NBLOCKS(statbuf) \
  (S_ISREG ((statbuf).st_mode) || S_ISDIR ((statbuf).st_mode) \
   ? (statbuf).st_blocks * ST_BLKSIZE (statbuf) / ST_NBLOCKSIZE : 0)
#   endif
#  endif
# endif
#endif

#ifndef ST_NBLOCKS
# define ST_NBLOCKS(statbuf) ((statbuf).st_blocks)
#endif

#ifndef ST_NBLOCKSIZE
# ifdef S_BLKSIZE
#  define ST_NBLOCKSIZE S_BLKSIZE
# else
#  define ST_NBLOCKSIZE 512
# endif
#endif

#endif /* STAT_SIZE_H */

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