/* See LICENSE file for copyright and license details. */
#include "internals"

#include <stdlib.h>
#include <string.h>


void
zbset(z_t a, z_t b, size_t bit, int action)
{
	zahl_char_t x = 1;
	size_t chars;

	chars = FLOOR_BITS_TO_CHARS(bit);
	bit = BITS_IN_LAST_CHAR(bit);
	x <<= bit;

	if (a != b)
		zset(a, b);

	if (action) {
		if (zzero(a)) {
			a->used = 0;
			SET_SIGNUM(a, 1);
		}
		if (a->used <= chars) {
			if (a->alloced <= chars) {
				a->alloced = chars + 1;
				a->chars = realloc(a->chars, a->alloced * sizeof(*(a->chars)));
			}
			memset(a->chars + a->used, 0, (chars - a->used + 1) * sizeof(*(a->chars)));
		}
	}

	if (action > 0) {
		a->chars[chars] |= x;
		return;
	} else if (action < 0) {
		a->chars[chars] ^= x;
	} else if (a->used > chars) {
		a->chars[chars] &= ~x;
	}

	while (a->used && !a->chars[a->used - 1])
		a->used--;
	if (!a->used)
		SET_SIGNUM(a, 0);
}