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// Copyright 2013 The Servo Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// option. This file may not be copied, modified, or distributed
// except according to those terms.
/// Trait for testing approximate equality
pub trait ApproxEq<Eps> {
/// Default epsilon value
fn approx_epsilon() -> Eps;
/// Returns `true` is this object is approximately equal to the other one, using
/// a provided epsilon value.
fn approx_eq_eps(&self, other: &Self, approx_epsilon: &Eps) -> bool;
/// Returns `true` is this object is approximately equal to the other one, using
/// the `approx_epsilon()` epsilon value.
fn approx_eq(&self, other: &Self) -> bool {
self.approx_eq_eps(other, &Self::approx_epsilon())
}
}
macro_rules! approx_eq {
($ty:ty, $eps:expr) => {
impl ApproxEq<$ty> for $ty {
#[inline]
fn approx_epsilon() -> $ty {
$eps
}
#[inline]
fn approx_eq_eps(&self, other: &$ty, approx_epsilon: &$ty) -> bool {
num_traits::Float::abs(*self - *other) < *approx_epsilon
}
}
};
}
approx_eq!(f32, 1.0e-6);
approx_eq!(f64, 1.0e-6);