org.jose4j.lang.Maths Maven / Gradle / Ivy
package org.jose4j.lang;
public class Maths
{
//Two's complement -> if the leftmost bit is 0, the number is positive. Otherwise, it's negative.
public static long add(long x, long y)
{
long result = x + y;
// if both arguments have the opposite sign of the result
if (0 > ((x ^ result) & (y ^ result)))
{
throw new ArithmeticException("long overflow adding: " + x + " + " + y + " = " + result);
}
return result;
}
public static long subtract(long x, long y)
{
long result = x - y;
// when arguments have different signs and sign of result is different than the sign of x
if (0 > ((x ^ y) & (x ^ result)))
{
throw new ArithmeticException("long overflow subtracting: " + x + " - " + y + " = " + result);
}
return result;
}
}