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SubjectRe: [PATCH 5/7] omfs: add bitmap routines
Date
On Thursday 27 March 2008, Bob Copeland wrote:

> +static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
> +
> +unsigned long omfs_count_free(struct super_block *sb)
> +{
> + unsigned int i, j, count = 0;
> + unsigned char *map;
> + unsigned long sum = 0;
> + struct omfs_sb_info *sbi = OMFS_SB(sb);
> +
> + for (i = 0; i < sbi->s_imap_size; i++) {
> + map = (unsigned char *) sbi->s_imap[i];
> + for (j = 0; j < sb->s_blocksize &&
> + count + j < sbi->s_num_blocks/8; j++)
> + sum += nibblemap[map[j] & 0xf] +
> + nibblemap[(map[j] >> 4) & 0xf];
> + count += sb->s_blocksize;
> + }
> + return sum;
> +}

I think it would be helpful to express this using hweight64.


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