| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/ext3/bitmap.c |
| 3 | * |
| 4 | * Copyright (C) 1992, 1993, 1994, 1995 |
| 5 | * Remy Card (card@masi.ibp.fr) |
| 6 | * Laboratoire MASI - Institut Blaise Pascal |
| 7 | * Universite Pierre et Marie Curie (Paris VI) |
| 8 | */ |
| 9 | |
| 10 | #include <linux/buffer_head.h> |
| Ben Dooks | 381be254 | 2005-10-30 15:02:56 -0800 | [diff] [blame] | 11 | #include "bitmap.h" |
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | |
| 13 | static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0}; |
| 14 | |
| 15 | unsigned long ext3_count_free (struct buffer_head * map, unsigned int numchars) |
| 16 | { |
| 17 | unsigned int i; |
| 18 | unsigned long sum = 0; |
| 19 | |
| 20 | if (!map) |
| 21 | return (0); |
| 22 | for (i = 0; i < numchars; i++) |
| 23 | sum += nibblemap[map->b_data[i] & 0xf] + |
| 24 | nibblemap[(map->b_data[i] >> 4) & 0xf]; |
| 25 | return (sum); |
| 26 | } |