[deliverable/linux.git] / fs / ext2 / bitmap.c

/*
 *  linux/fs/ext2/bitmap.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 */

#include <linux/buffer_head.h>

static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};

unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars)
{
	unsigned int i;
	unsigned long sum = 0;
	
	if (!map) 
		return (0);
	for (i = 0; i < numchars; i++)
		sum += nibblemap[map->b_data[i] & 0xf] +
			nibblemap[(map->b_data[i] >> 4) & 0xf];
	return (sum);
}
Commit	Line	Data
1da177e4 LT	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
	12	static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
	13
	14	unsigned 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	}