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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2014 by Michael Sevakis
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef BITARRAY_H
#define BITARRAY_H
/* Type-checked bit array definitions */
/* All this stuff gets optimized into very simple object code */
#define BITARRAY_WORD_BITS \
(sizeof (unsigned int) * 8)
#define BITARRAY_NWORDS(bits) \
(((bits) + BITARRAY_WORD_BITS - 1) / BITARRAY_WORD_BITS)
#define BITARRAY_BITWORD(bitnum) \
((bitnum) / BITARRAY_WORD_BITS)
#define BITARRAY_WORDBIT(bitnum) \
((bitnum) % BITARRAY_WORD_BITS)
#define BITARRAY_NBIT(word, bit) \
((word)*BITARRAY_WORD_BITS + (bit))
#define BITARRAY_BITS(bits) \
(BITARRAY_NWORDS(bits)*BITARRAY_WORD_BITS)
#define BITARRAY_BITN(bitnum) \
(1u << BITARRAY_WORDBIT(bitnum))
/** Iterators **/
#include "config.h"
#include <stdint.h>
#if (defined(CPU_ARM) && ARM_ARCH >= 5) || UINT32_MAX < UINT_MAX
#define __BITARRAY_CTZ(wval) __builtin_ctz(wval)
#else
#include "system.h"
#define __BITARRAY_CTZ(wval) find_first_set_bit(wval)
#endif
#define __BITARRAY_POPCNT(wval) __builtin_popcount(wval)
#ifndef BIT_N
#define BIT_N(n) (1u << (n))
#endif
/* Enumerate each word index */
#define FOR_EACH_BITARRAY_WORD_INDEX(nwords, index) \
for (unsigned int index = 0, _nwords = (nwords); \
index < _nwords; index++)
/* Enumerate each word value */
#define FOR_EACH_BITARRAY_WORD(a, wval) \
FOR_EACH_BITARRAY_WORD_INDEX(ARRAYLEN((a)->words), _w) \
for (unsigned int wval = (a)->words[_w], _ = 1; _; _--)
/* Enumerate the bit number of each set bit of a word in sequence */
#define FOR_EACH_BITARRAY_SET_WORD_BIT(wval, bit) \
for (unsigned int _wval = (wval), bit; \
_wval ? (((bit) = __BITARRAY_CTZ(_wval)), 1) : 0; \
_wval &= ~BIT_N(bit))
/* Enumerate the bit number of each set bit in the bit array in sequence */
#define FOR_EACH_BITARRAY_SET_BIT_ARR(nwords, words, nbit) \
FOR_EACH_BITARRAY_WORD_INDEX(nwords, _w) \
FOR_EACH_BITARRAY_SET_WORD_BIT(words[_w], _bit) \
for (unsigned int nbit = BITARRAY_NBIT(_w, _bit), _ = 1; _; _--)
/* As above but takes an array type for an argument */
#define FOR_EACH_BITARRAY_SET_BIT(a, nbit) \
FOR_EACH_BITARRAY_SET_BIT_ARR(ARRAYLEN((a)->words), (a)->words, nbit)
/** Base functions (called by typed functions) **/
/* Return the word associated with the bit */
static inline unsigned int
__bitarray_get_word(unsigned int words[], unsigned int bitnum)
{
return words[BITARRAY_BITWORD(bitnum)];
}
/* Set the word associated with the bit */
static inline void
__bitarray_set_word(unsigned int words[], unsigned int bitnum,
unsigned int wordval)
{
words[BITARRAY_BITWORD(bitnum)] = wordval;
}
/* Set the bit at index 'bitnum' to '1' */
static inline void
__bitarray_set_bit(unsigned int words[], unsigned int bitnum)
{
unsigned int word = BITARRAY_BITWORD(bitnum);
unsigned int bit = BITARRAY_BITN(bitnum);
words[word] |= bit;
}
/* Set the bit at index 'bitnum' to '0' */
static inline void
__bitarray_clear_bit(unsigned int words[], unsigned int bitnum)
{
unsigned int word = BITARRAY_BITWORD(bitnum);
unsigned int bit = BITARRAY_BITN(bitnum);
words[word] &= ~bit;
}
/* Return the value of the specified bit ('0' or '1') */
static inline unsigned int
__bitarray_test_bit(const unsigned int words[], unsigned int bitnum)
{
unsigned int word = BITARRAY_BITWORD(bitnum);
unsigned int nbit = BITARRAY_WORDBIT(bitnum);
return (words[word] >> nbit) & 1u;
}
/* Check if all bits in the bit array are '0' */
static inline bool
__bitarray_is_clear(const unsigned int words[], unsigned int nbits)
{
FOR_EACH_BITARRAY_WORD_INDEX(BITARRAY_NWORDS(nbits), word)
{
if (words[word] != 0)
return false;
}
return true;
}
/* Set every bit in the array to '0' */
static inline void
__bitarray_clear(unsigned int words[], unsigned int nbits)
{
FOR_EACH_BITARRAY_WORD_INDEX(BITARRAY_NWORDS(nbits), word)
words[word] = 0;
}
/* Set every bit in the array to '1' */
static inline void
__bitarray_set(unsigned int words[], unsigned int nbits)
{
FOR_EACH_BITARRAY_WORD_INDEX(BITARRAY_NWORDS(nbits), word)
words[word] = ~0u;
}
/* Find the lowest-indexed '1' bit in the bit array, returning the size of
the array if none are set */
static inline unsigned int
__bitarray_ffs(const unsigned int words[], unsigned int nbits)
{
FOR_EACH_BITARRAY_SET_BIT_ARR(BITARRAY_NWORDS(nbits), words, nbit)
return nbit;
return BITARRAY_BITS(nbits);
}
/* Return the number of bits currently set to '1' in the bit array */
static inline unsigned int
__bitarray_popcount(const unsigned int words[], unsigned int nbits)
{
unsigned int count = 0;
FOR_EACH_BITARRAY_WORD_INDEX(BITARRAY_NWORDS(nbits), word)
count += __BITARRAY_POPCNT(words[word]);
return count;
}
/**
* Giant macro to define all the typed functions
* typename: The name of the type (e.g. myarr_t myarr;)
* fnprefix: The prefix all functions get (e.g. myarr_set_bit)
* nbits : The minimum number of bits the array is meant to hold
* (the implementation rounds this up to the word size
* and all words may be fully utilized)
*
* uses 'typedef' to freely change from, e.g., struct to union without
* changing source code
*/
#define BITARRAY_TYPE_DECLARE(typename, fnprefix, nbits) \
typedef struct \
{ \
unsigned int words[BITARRAY_NWORDS(nbits)]; \
} typename; \
static inline unsigned int \
fnprefix##_get_word(typename *array, unsigned int bitnum) \
{ return __bitarray_get_word(array->words, bitnum); } \
static inline void \
fnprefix##_set_word(typename *array, unsigned int bitnum, \
unsigned int wordval) \
{ __bitarray_set_word(array->words, bitnum, wordval); } \
static inline void \
fnprefix##_set_bit(typename *array, unsigned int bitnum) \
{ __bitarray_set_bit(array->words, bitnum); } \
static inline void \
fnprefix##_clear_bit(typename *array, unsigned int bitnum) \
{ __bitarray_clear_bit(array->words, bitnum); } \
static inline unsigned int \
fnprefix##_test_bit(const typename *array, unsigned int bitnum) \
{ return __bitarray_test_bit(array->words, bitnum); } \
static inline bool \
fnprefix##_is_clear(const typename *array) \
{ return __bitarray_is_clear(array->words, nbits); } \
static inline void \
fnprefix##_clear(typename *array) \
{ __bitarray_clear(array->words, nbits); } \
static inline void \
fnprefix##_set(typename *array) \
{ __bitarray_set(array->words, nbits); } \
static inline unsigned int \
fnprefix##_ffs(const typename *array) \
{ return __bitarray_ffs(array->words, nbits); } \
static inline unsigned int \
fnprefix##_popcount(const typename *array) \
{ return __bitarray_popcount(array->words, nbits); }
#endif /* BITARRAY_H */
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