Overflows don't seem to be part of the builtin packages in go.
What is the best way to test that you don't overflow when multiplying 2 integers ?
Something similar to Java Math.multiplyExact ...
Add a comment
|
1 Answer
It'd be possible for you to write your own multiplyExact based on the suggestions on this thread:
https://groups.google.com/forum/#!msg/golang-nuts/h5oSN5t3Au4/KaNQREhZh0QJ
const mostNegative = -(mostPositive + 1)
const mostPositive = 1<<63 - 1
func multiplyExact(a, b int64) (int64, error) {
result := a * b
if a == 0 || b == 0 || a == 1 || b == 1 {
return result, nil
}
if a == mostNegative || b == mostNegative {
return result, fmt.Errorf("Overflow multiplying %v and %v", a, b)
}
if result/b != a {
return result, fmt.Errorf("Overflow multiplying %v and %v", a, b)
}
return result, nil
}
Playground: https://play.golang.org/p/V_TSC44VcPY
