Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1/*
2 * linux/fs/ext2/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>
11
12static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
13
14unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars)
15{
16 unsigned int i;
17 unsigned long sum = 0;
18
19 if (!map)
20 return (0);
21 for (i = 0; i < numchars; i++)
22 sum += nibblemap[map->b_data[i] & 0xf] +
23 nibblemap[(map->b_data[i] >> 4) & 0xf];
24 return (sum);
25}