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/*
** large bit array operations by Scott Dudley
** with modifications by Auke Reitsma and Bob Stout
**
** Public domain
*/
#include <limits.h>
/*
** The following macros assume CHAR_BIT is one of either 8, 16, or 32
*/
#define MASK CHAR_BIT-1
#define SHIFT ((CHAR_BIT==8)?3:(CHAR_BIT==16)?4:8)
#define BitOff(a,x) ((void)((a)[(x)>>SHIFT] &= ~(1 << ((x)&MASK))))
#define BitOn(a,x) ((void)((a)[(x)>>SHIFT] |= (1 << ((x)&MASK))))
#define BitFlip(a,x) ((void)((a)[(x)>>SHIFT] ^= (1 << ((x)&MASK))))
#define IsBit(a,x) ((a)[(x)>>SHIFT] & (1 << ((x)&MASK)))
#include <stdio.h>
#include <string.h>
int main(void)
{
char array[64];
memset(array, '\0', sizeof(array));
BitOn(array, 5);
BitOn(array, 12);
BitOn(array, 500);
if (IsBit(array, 5) && IsBit(array, 12) && IsBit(array, 500))
puts("These functions seem to work!");
else puts("Something's broken here!");
BitFlip(array, 12);
BitOff(array, 5);
if (!IsBit(array, 5) && !IsBit(array, 12) && IsBit(array, 500))
puts("These functions still seem to work!");
else puts("Something's broken here!");
return 0;
}
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