Simulating integer overflow in Python

Question

Python 2 has two integer datatypes int and long, and automatically converts between them as necessary, especially in order to avoid integer overflo

Answer 1

Does your function use division or right bit-shifting? If not then you don't need to worry about overflows at each stage of the calculation because you will always get the "correct" answer modulo 2^32 or 2^64. Before returning the result (or before doing division or right bit-shifting) you can normalize back to the standard integer range using something like

import sys

HALF_N = sys.maxint + 1
N = HALF_N * 2

def normalize(value):
    return (value + HALF_N) % N - HALF_N