/* bitfield.h - bitfield macros */
/*
 * PUBLIC DOMAIN - NO COPYRIGHT CLAIMED - Jonathan Mayo - July 2005
 *
 * Updated January 2010
 */

#ifndef BITFIELD_H
#define BITFIELD_H
#include <limits.h>

/* return in type sized elements to create a bitfield of 'bits' bits */
#define BITFIELD(bits, type) (((bits)+(CHAR_BIT*sizeof(type))-1)/(CHAR_BIT*sizeof(type)))

/* size of a word */
#define BITWORDSZ(x) (CHAR_BIT*sizeof *(x))

/* set bit position 'bit' in bitfield x */
#define BITSET(x, bit) (x)[(bit)/(BITWORDSZ(x))]|=1ul<<((bit)%BITWORDSZ(x))

/* clear bit position 'bit' in bitfield x */
#define BITCLR(x, bit) (x)[(bit)/(BITWORDSZ(x))]&=~(1ul<<((bit)%BITWORDSZ(x)))

/* toggle bit position 'bit' in bitfield x */
#define BITINV(x, bit) (x)[(bit)/(BITWORDSZ(x))]^=1ul<<((bit)%BITWORDSZ(x))

/* return a large non-zero number if the bit is set, zero if clear */
#define BITTEST(x, bit) ((x)[(bit)/(BITWORDSZ(x))]&(1ul<<((bit)%BITWORDSZ(x))))

/* checks that bit is in range for bitfield x.
 * doesn't work if x is a pointer, must be an array. */
#define BITRANGE(x, bit) ((bit)<(sizeof(x)*CHAR_BIT))

/* example/test program
#include <stdio.h>
#include <stdlib.h>
#include "bitfield.h"
int main(int argc, char **argv) {
    unsigned long bits[BITFIELD(100,unsigned long)] = {0};
    int i;
    printf("size=%d bytes (%d bits)\n",sizeof bits, CHAR_BIT * sizeof bits);
    for(i=1;i<argc;i++) {
        unsigned f;
        f=strtoul(argv[i], 0, 0);
        BITSET(bits, f);
    }
    for(i=0;i<(sizeof bits/sizeof *bits);i++) {
        printf("bits[%d]=0x%08lX\n", i, bits[i]);
    }

    return 0;
}
*/

#endif