Root/fs/ext3/bitmap.c

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>
11#include <linux/jbd.h>
12#include <linux/ext3_fs.h>
13
14#ifdef EXT3FS_DEBUG
15
16static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
17
18unsigned long ext3_count_free (struct buffer_head * map, unsigned int numchars)
19{
20    unsigned int i;
21    unsigned long sum = 0;
22
23    if (!map)
24        return (0);
25    for (i = 0; i < numchars; i++)
26        sum += nibblemap[map->b_data[i] & 0xf] +
27            nibblemap[(map->b_data[i] >> 4) & 0xf];
28    return (sum);
29}
30
31#endif /* EXT3FS_DEBUG */
32
33

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