Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH 5/7] omfs: add bitmap routines | Date | Fri, 28 Mar 2008 04:51:10 +0100 |
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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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