Struct ratio::Ratio

pub struct Ratio { /* private fields */ }

The ratio type.

It converts numerator / denominator to mult / (1 << shift) to avoid u128 division on calculation. The shift is as large as possible to improve precision.

Currently, it only supports u32 as the numerator and denominator.

Implementations

impl Ratio

pub const fn zero() -> Self

The zero ratio.

pub const fn new(numerator: u32, denominator: u32) -> Self

Creates a new ratio numerator / denominator.

pub const fn inverse(&self) -> Self

Get the inverse ratio.

Examples

use ratio::Ratio;

let ratio = Ratio::new(1, 2);
assert_eq!(ratio.inverse(), Ratio::new(2, 1));

pub const fn mul_trunc(&self, value: u64) -> u64

Multiplies the ratio by a value and rounds the result down.

Examples

use ratio::Ratio;

let ratio = Ratio::new(2, 3);
assert_eq!(ratio.mul_trunc(99), 66);  // 99 * 2 / 3 = 66
assert_eq!(ratio.mul_trunc(100), 66); // trunc(100 * 2 / 3) = trunc(66.66...) = 66

pub const fn mul_round(&self, value: u64) -> u64

Multiplies the ratio by a value and rounds the result to the nearest whole number.

Examples

use ratio::Ratio;

let ratio = Ratio::new(2, 3);
assert_eq!(ratio.mul_round(99), 66);  // 99 * 2 / 3 = 66
assert_eq!(ratio.mul_round(100), 67); // round(100 * 2 / 3) = round(66.66...) = 67

Trait Implementations

impl Debug for Ratio

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Ratio

fn eq(&self, other: &Ratio) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.