use std::num::Int;
#[inline]
pub fn div_rem<T: Int>(a: T, b: T) -> (T, T) {
(a / b, a % b)
}
#[inline]
pub fn div_floor<T: Int>(a: T, b: T) -> T {
div_mod_floor(a, b).0
}
#[inline]
pub fn mod_floor<T: Int>(a: T, b: T) -> T {
div_mod_floor(a, b).1
}
#[inline]
pub fn div_mod_floor<T: Int>(a: T, b: T) -> (T, T) {
let zero = Int::zero();
let one = Int::one();
match (a / b, a % b) {
(d, r) if (r > zero && b < zero) || (r < zero && b > zero) => (d - one, r + b),
(d, r) => (d, r),
}
}
#[cfg(test)]
mod tests {
use super::{mod_floor, div_mod_floor};
#[test]
fn test_mod_floor() {
assert_eq!(mod_floor( 8, 3), 2);
assert_eq!(mod_floor( 8, -3), -1);
assert_eq!(mod_floor(-8, 3), 1);
assert_eq!(mod_floor(-8, -3), -2);
assert_eq!(mod_floor( 1, 2), 1);
assert_eq!(mod_floor( 1, -2), -1);
assert_eq!(mod_floor(-1, 2), 1);
assert_eq!(mod_floor(-1, -2), -1);
}
#[test]
fn test_div_mod_floor() {
assert_eq!(div_mod_floor( 8, 3), ( 2, 2));
assert_eq!(div_mod_floor( 8, -3), (-3, -1));
assert_eq!(div_mod_floor(-8, 3), (-3, 1));
assert_eq!(div_mod_floor(-8, -3), ( 2, -2));
assert_eq!(div_mod_floor( 1, 2), ( 0, 1));
assert_eq!(div_mod_floor( 1, -2), (-1, -1));
assert_eq!(div_mod_floor(-1, 2), (-1, 1));
assert_eq!(div_mod_floor(-1, -2), ( 0, -1));
}
}