coreutils/lib/fileblocks.c

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/* Convert file size to number of blocks on System V-like machines.
Copyright (C) 1990, 1997, 1998, 1999 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 2, 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. */
/* Written by Brian L. Matthews, blm@6sceng.UUCP. */
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include <sys/types.h>
#if HAVE_SYS_PARAM_H
# include <sys/param.h>
#endif
#if !HAVE_STRUCT_STAT_ST_BLOCKS && !defined _POSIX_SOURCE && defined BSIZE
# if HAVE_UNISTD_H
# include <unistd.h>
# endif
# ifndef NINDIR
# if defined (__DJGPP__)
typedef long daddr_t; /* for disk address */
# endif
/* Some SysV's, like Irix, seem to lack this. Hope it's correct. */
/* Number of inode pointers per indirect block. */
# define NINDIR (BSIZE / sizeof (daddr_t))
# endif /* !NINDIR */
/* Number of direct block addresses in an inode. */
# define NDIR 10
/* Return the number of 512-byte blocks in a file of SIZE bytes. */
off_t
st_blocks (off_t size)
{
off_t datablks = size / 512 + (size % 512 != 0);
off_t indrblks = 0;
if (datablks > NDIR)
{
indrblks = (datablks - NDIR - 1) / NINDIR + 1;
if (datablks > NDIR + NINDIR)
{
indrblks += (datablks - NDIR - NINDIR - 1) / (NINDIR * NINDIR) + 1;
if (datablks > NDIR + NINDIR + NINDIR * NINDIR)
indrblks++;
}
}
return datablks + indrblks;
}
#else
/* This declaration is solely to ensure that after preprocessing
this file is never empty. */
extern int textutils_fileblocks_unused;
#endif