67 lines
1.9 KiB
C
67 lines
1.9 KiB
C
/* ************************************************************************** */
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/* */
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/* ::: :::::::: */
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/* bitfield.c :+: :+: :+: */
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/* +:+ +:+ +:+ */
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/* By: jhalford <jack@crans.org> +#+ +:+ +#+ */
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/* +#+#+#+#+#+ +#+ */
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/* Created: 2017/10/09 14:44:16 by jhalford #+# #+# */
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/* Updated: 2017/10/24 21:04:39 by jhalford ### ########.fr */
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/* */
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/* ************************************************************************** */
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#include "libft.h"
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#include <stdlib.h>
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/*
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** ==== Wrapper around GCC builtins for ====
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** ==== arbitrarily large sized bitfields ====
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**
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** todo
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** - up and down iterator
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**
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*/
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/*
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** Turn bit on
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*/
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extern inline void bitfield_biton(t_bitblock field[], uint64_t bit)
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{
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field[bit / BLOCKSIZE + 1] |= (1 << (bit % BLOCKSIZE));
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}
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/*
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** Turn bit off
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*/
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extern inline void bitfield_bitoff(t_bitblock field[], uint64_t bit)
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{
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field[bit / BLOCKSIZE + 1] &= ~(1 << bit % BLOCKSIZE);
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}
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/*
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** Least Significant Bit (rightmost)
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*/
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extern inline uint64_t bitfield_lsb(t_bitblock field[])
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{
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int block;
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uint64_t size;
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block = 0;
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size = field[0];
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while (!field[++block])
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if ((block+1) * BLOCKSIZE > size) return (-1);
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return (block * BLOCKSIZE + __builtin_ctzll(field[block] ^ (~field[block] + 1)) - 1);
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}
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/*
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** Count the number of 1-bits in field
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*/
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extern inline uint64_t bitfield_popcount(t_bitblock field[], uint64_t size)
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{
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int block = -1;
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int count = 0;
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while (++block * BLOCKSIZE < size)
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count += __builtin_popcountll(field[block]);
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return (count);
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}
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