cgmath/src/approx.rs
2015-11-03 14:00:39 +11:00

73 lines
2.2 KiB
Rust

// Copyright 2014 The CGMath Developers. For a full listing of the authors,
// refer to the Cargo.toml file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use rust_num::{Float, NumCast};
use rust_num::traits::cast;
pub trait ApproxEq: Sized {
type Epsilon: NumCast + Float;
fn approx_epsilon() -> Self::Epsilon {
cast(1.0e-5f64).unwrap()
}
fn approx_eq(&self, other: &Self) -> bool {
self.approx_eq_eps(other, &Self::approx_epsilon())
}
fn approx_eq_eps(&self, other: &Self, epsilon: &Self::Epsilon) -> bool;
}
macro_rules! approx_float(
($S:ident) => (
impl ApproxEq for $S {
type Epsilon = $S;
#[inline]
fn approx_eq_eps(&self, other: &$S, epsilon: &$S) -> bool {
(*self - *other).abs() < *epsilon
}
}
)
);
approx_float!(f32);
approx_float!(f64);
#[macro_export]
macro_rules! assert_approx_eq_eps(
($given: expr, $expected: expr, $eps: expr) => ({
let eps = &($eps);
let (given_val, expected_val) = (&($given), &($expected));
if !given_val.approx_eq_eps(expected_val, eps) {
panic!("assertion failed: `left ≈ right` (left: `{:?}`, right: `{:?}`, tolerance: `{:?}`)",
*given_val, *expected_val, *eps
);
}
})
);
#[macro_export]
macro_rules! assert_approx_eq(
($given: expr, $expected: expr) => ({
let (given_val, expected_val) = (&($given), &($expected));
if !given_val.approx_eq(expected_val) {
panic!("assertion failed: `left ≈ right` (left: `{:?}`, right: `{:?}`)",
*given_val, *expected_val
);
}
})
);