atoi in acs

// ============================================================================
// String-to-integer
function int atoi (str a) {
	int val, neg;
	int mul = 1;

	for (int i = StrLen (a) - 1; i >= 0; i--) {
		int c = GetChar (a, i);
		if (c == ' ' || c == '\n' || c == '\t' || c == '\r')
			continue; // Skip past whitespace

		// Minus sign
		if (c == '-' && !neg && val != 0) {
			neg = true;
			continue;
		}

		// Number values
		if (c >= '0' && c <= '9') {
			val += mul * (c - '0');
			mul *= 10;
			continue;
		}

		// If there's any junk, we stop now.
		return 0;
	}

	if (neg)
		val *= -1;
	return val;
}

function str itoa (int a) {
	return strparam (d:a);
}