use crate::fixed_point::FixedPoint;
impl FixedPoint for u64 {
fn fixed_mul_floor(self, y: u64, denominator: u64) -> Option<u64> {
mul_div_floor(self, y, denominator)
}
fn fixed_mul_ceil(self, y: u64, denominator: u64) -> Option<u64> {
mul_div_ceil(self, y, denominator)
}
fn fixed_div_floor(self, y: u64, denominator: u64) -> Option<u64> {
mul_div_floor(self, denominator, y)
}
fn fixed_div_ceil(self, y: u64, denominator: u64) -> Option<u64> {
mul_div_ceil(self, denominator, y)
}
}
fn mul_div_floor(x: u64, y: u64, z: u64) -> Option<u64> {
return match x.checked_mul(y) {
Some(r) => r.checked_div(z),
None => {
let res_u128 = (x as u128).checked_mul(y as u128)?.checked_div(z as u128)?;
if res_u128 > u64::MAX as u128 {
return None;
}
Some(res_u128 as u64)
}
};
}
fn mul_div_ceil(x: u64, y: u64, z: u64) -> Option<u64> {
return match x.checked_mul(y) {
Some(r) => {
let remainder = r.checked_rem_euclid(z)?;
(r / z).checked_add(if remainder > 0 { 1 } else { 0 })
}
None => {
let r_u128 = (x as u128).checked_mul(y as u128)?;
let remainder = r_u128.checked_rem_euclid(z as u128)?;
let res_u128 = r_u128 / (z as u128);
if res_u128 > u64::MAX as u128 {
return None;
}
(res_u128 as u64).checked_add(if remainder > 0 { 1 } else { 0 })
}
};
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_fixed_mul_floor_rounds_down() {
let x: u64 = 1_5391283;
let y: u64 = 314_1592653;
let denominator: u64 = 1_0000001;
let result = x.fixed_mul_floor(y, denominator).unwrap();
assert_eq!(result, 483_5313675)
}
#[test]
fn test_fixed_mul_floor_large_number() {
let x: u64 = 18_446_744_073;
let y: u64 = 1_000_000_000;
let denominator: u64 = 1_000_000_000;
let result = x.fixed_mul_floor(y, denominator).unwrap();
assert_eq!(result, 18_446_744_073)
}
#[test]
fn test_fixed_mul_floor_phantom_overflow_uses_u128() {
let x: u64 = 18_446_744_073;
let y: u64 = 2_000_000_000;
let denominator: u64 = 1_000_000_000;
let result = x.fixed_mul_floor(y, denominator).unwrap();
assert_eq!(result, 36_893_488_146);
}
#[test]
fn test_fixed_mul_floor_result_overflow() {
let x: u64 = 18_446_744_073_000_000_000;
let y: u64 = 2_000_000_000;
let denominator: u64 = 1_000_000_000;
let result = x.fixed_mul_floor(y, denominator);
assert_eq!(result, None);
}
#[test]
fn test_fixed_mul_ceil_rounds_up() {
let x: u64 = 1_5391283;
let y: u64 = 314_1592653;
let denominator: u64 = 1_0000001;
let result = x.fixed_mul_ceil(y, denominator).unwrap();
assert_eq!(result, 483_5313676)
}
#[test]
fn test_fixed_mul_ceil_large_number() {
let x: u64 = 18_446_744_073;
let y: u64 = 1_000_000_000;
let denominator: u64 = 1_000_000_000;
let result = x.fixed_mul_ceil(y, denominator).unwrap();
assert_eq!(result, 18_446_744_073)
}
#[test]
fn test_fixed_mul_ceil_phantom_overflow_uses_u128() {
let x: u64 = 18_446_744_073;
let y: u64 = 2_000_000_000;
let denominator: u64 = 1_000_000_000;
let result = x.fixed_mul_ceil(y, denominator).unwrap();
assert_eq!(result, 36_893_488_146);
}
#[test]
fn test_fixed_mul_ceil_result_overflow() {
let x: u64 = 18_446_744_073_000_000_000;
let y: u64 = 2_000_000_000;
let denominator: u64 = 1_000_000_000;
let result = x.fixed_mul_ceil(y, denominator);
assert_eq!(result, None);
}
#[test]
fn test_fixed_div_floor_rounds_down() {
let x: u64 = 314_1592653;
let y: u64 = 1_5391280;
let denominator: u64 = 1_0000000;
let result = x.fixed_div_floor(y, denominator).unwrap();
assert_eq!(result, 204_1150997)
}
#[test]
fn test_fixed_div_floor_large_number() {
let x: u64 = 18_446_744_073;
let y: u64 = 1_000_000_000;
let denominator: u64 = 1_000_000_000;
let result = x.fixed_div_floor(y, denominator).unwrap();
assert_eq!(result, 18_446_744_073)
}
#[test]
fn test_fixed_div_floor_phantom_overflow_uses_u128() {
let x: u64 = 18_446_744_073;
let y: u64 = 2_000_000_000;
let denominator: u64 = 1_000_000_000;
let result = x.fixed_div_floor(y, denominator).unwrap();
assert_eq!(result, 9_223_372_036);
}
#[test]
fn test_fixed_div_floor_result_overflow() {
let x: u64 = 18_446_744_073_000_000_000;
let y: u64 = 2_000_000_000;
let denominator: u64 = 4_000_000_000;
let result = x.fixed_div_floor(y, denominator);
assert_eq!(result, None);
}
#[test]
fn test_fixed_div_ceil_rounds_up() {
let x: u64 = 314_1592653;
let y: u64 = 1_5391280;
let denominator: u64 = 1_0000000;
let result = x.fixed_div_ceil(y, denominator).unwrap();
assert_eq!(result, 204_1150998)
}
#[test]
fn test_fixed_div_ceil_large_number() {
let x: u64 = 18_446_744_073;
let y: u64 = 1_000_000_000;
let denominator: u64 = 1_000_000_000;
let result = x.fixed_div_ceil(y, denominator).unwrap();
assert_eq!(result, 18_446_744_073)
}
#[test]
fn test_fixed_div_ceil_phantom_overflow_uses_u128() {
let x: u64 = 18_446_744_073;
let y: u64 = 2_000_000_000;
let denominator: u64 = 1_000_000_000;
let result = x.fixed_div_ceil(y, denominator).unwrap();
assert_eq!(result, 9_223_372_037);
}
#[test]
fn test_fixed_div_ceil_result_overflow() {
let x: u64 = 18_446_744_073_000_000_000;
let y: u64 = 2_000_000_000;
let denominator: u64 = 4_000_000_000;
let result = x.fixed_div_ceil(y, denominator);
assert_eq!(result, None);
}
}