typedef int (*unary_predicate) (const void *elem);

/**
 * Finds first element in the array that satisfies specific criteria
 * @param base Specifies base address of array
 * @param nmemb Specifies number of elements in the array
 * @param size Specifies size in bytes of each element in the array
 * @param pred Specifies predicate used to determining what to search
 * @returns index of found element, or @nmemb if no elements found
 */
static size_t
find_if(void *base, size_t nmemb, size_t size, unary_predicate pred)
{
	for (size_t i = 0; i < nmemb; i++) {
		const void *elem = (const unsigned char *)base + size * i;
		if (!pred(elem)) {
			return i;
		}
	}
	return nmemb;
}

/**
 * Removes all elements satisfying specific criteria from the array.
 * @param base Specifies base address of array to remove from
 * @param nmemb Specifies number of elements in the array
 * @param size Specifies size in bytes of each element in the array
 * @param pred Specifies predicate used to determine what to remove
 * @returns new array size
 */
static size_t
remove_if(void *base, size_t nmemb, size_t size, unary_predicate pred)
{
	size_t result = find_if(base, nmemb, size, pred);
	for (size_t i = result + 1; i < nmemb; i++) {
		const void *elem = (const unsigned char *)base + size * i;
		if (!pred(elem)) {
			void *dest = (unsigned char *)base + size * result;
			memcpy(dest, elem, size);
			result += 1;
		}
	}
	return result;
}