lib/fileblocks.c

   1 /* Convert file size to number of blocks on System V-like machines.
   2    Copyright (C) 1990 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 2, or (at your option)
   7    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, write to the Free Software
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  17
  18 /* Written by Brian L. Matthews, blm@6sceng.UUCP. */
  19 \f
  20 #if !defined (HAVE_ST_BLOCKS) && !defined(_POSIX_SOURCE)
  21 #include <sys/types.h>
  22 #include <sys/param.h>
  23
  24 #ifndef NINDIR
  25 /* Some SysV's, like Irix, seem to lack these.  Hope they're correct. */
  26 /* Size of a indirect block, in bytes. */
  27 #define BSIZE 1024
  28
  29 /* Number of inode pointers per indirect block. */
  30 #define NINDIR (BSIZE/sizeof(daddr_t))
  31 #endif /* !NINDIR */
  32
  33 /* Number of direct block addresses in an inode. */
  34 #define NDIR    10
  35
  36 /* Return the number of 512-byte blocks in a file of SIZE bytes. */
  37
  38 long
  39 st_blocks (size)
  40      long size;
  41 {
  42   long datablks = (size + 512 - 1) / 512;
  43   long indrblks = 0;
  44
  45   if (datablks > NDIR)
  46     {
  47       indrblks = (datablks - NDIR - 1) / NINDIR + 1;
  48
  49       if (datablks > NDIR + NINDIR)
  50         {
  51           indrblks += (datablks - NDIR - NINDIR - 1) / (NINDIR * NINDIR) + 1;
  52
  53           if (datablks > NDIR + NINDIR + NINDIR * NINDIR)
  54             indrblks++;
  55         }
  56     }
  57
  58   return datablks + indrblks;
  59 }
  60 #endif