root/fs/ext2/bitmap.c

/* */

DEFINITIONS

1. ext2_count_free

   1 /*
   2  *  linux/fs/ext2/bitmap.c
   3  *
   4  *  Copyright (C) 1992, 1993  Remy Card (card@masi.ibp.fr)
   5  */
   6 
   7 #include <linux/fs.h>
   8 #include <linux/ext2_fs.h>
   9 
  10 static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
  11 
  12 unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars)
     /*  */
  13 {
  14         unsigned int i;
  15         unsigned long sum = 0;
  16         
  17         if (!map) 
  18                 return (0);
  19         for (i = 0; i < numchars; i++)
  20                 sum += nibblemap[map->b_data[i] & 0xf] +
  21                         nibblemap[(map->b_data[i] >> 4) & 0xf];
  22         return (sum);
  23 }

/* */