Files
solana/sdk/src/arithmetic.rs
Tyera Eulberg e5b644e830 Add trait for saturating arithmetic (#15812)
* Add SaturatingArithmetic trait

* Use Duration saturating arithmetic

* Use new macro to fix poh_config
2021-03-12 06:22:40 +00:00

46 lines
1.5 KiB
Rust

use std::time::Duration;
/// A helper trait for primitive types that do not yet implement saturating arithmetic methods
pub trait SaturatingArithmetic<T> {
fn sol_saturating_add(&self, rhs: Self) -> Self;
fn sol_saturating_sub(&self, rhs: Self) -> Self;
fn sol_saturating_mul(&self, rhs: T) -> Self;
}
/// Saturating arithmetic for Duration, until Rust support moves from nightly to stable
/// Duration::MAX is constructed manually, as Duration consts are not yet stable either.
impl SaturatingArithmetic<u32> for Duration {
fn sol_saturating_add(&self, rhs: Self) -> Self {
self.checked_add(rhs)
.unwrap_or_else(|| Self::new(u64::MAX, 1_000_000_000u32.saturating_sub(1)))
}
fn sol_saturating_sub(&self, rhs: Self) -> Self {
self.checked_sub(rhs).unwrap_or_else(|| Self::new(0, 0))
}
fn sol_saturating_mul(&self, rhs: u32) -> Self {
self.checked_mul(rhs)
.unwrap_or_else(|| Self::new(u64::MAX, 1_000_000_000u32.saturating_sub(1)))
}
}
#[cfg(test)]
pub mod tests {
use super::*;
#[test]
fn test_duration() {
let empty_duration = Duration::new(0, 0);
let max_duration = Duration::new(u64::MAX, 1_000_000_000 - 1);
let duration = Duration::new(u64::MAX, 0);
let add = duration.sol_saturating_add(duration);
assert_eq!(add, max_duration);
let sub = duration.sol_saturating_sub(max_duration);
assert_eq!(sub, empty_duration);
let mult = duration.sol_saturating_mul(u32::MAX);
assert_eq!(mult, max_duration);
}
}