relative_eq.rs - source
Description: Source of the Rust file `/Users/erlendbasso/.cargo/registry/src/github.com-1ecc6299db9ec823/approx-0.5.1/src/relative_eq.rs`.
Keywords: rust, rustlang, rust-lang

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    use core::{cell, f32, f64};
    #[cfg(feature = "num-complex")]
    use num_complex::Complex;
    use AbsDiffEq;

    /// Equality comparisons between two numbers using both the absolute difference and
    /// relative based comparisons.
    pub trait RelativeEq<Rhs = Self>: AbsDiffEq<Rhs>
    where
        Rhs: ?Sized,
    {
        /// The default relative tolerance for testing values that are far-apart.
        ///
        /// This is used when no `max_relative` value is supplied to the [`relative_eq`] macro.
        fn default_max_relative() -> Self::Epsilon;

        /// A test for equality that uses a relative comparison if the values are far apart.
        fn relative_eq(&self, other: &Rhs, epsilon: Self::Epsilon, max_relative: Self::Epsilon)
            -> bool;

        /// The inverse of [`RelativeEq::relative_eq`].
        fn relative_ne(
            &self,
            other: &Rhs,
            epsilon: Self::Epsilon,
            max_relative: Self::Epsilon,
        ) -> bool {
            !Self::relative_eq(self, other, epsilon, max_relative)
        }
    }

    ///////////////////////////////////////////////////////////////////////////////////////////////////
    // Base implementations
    ///////////////////////////////////////////////////////////////////////////////////////////////////

    // Implementation based on: [Comparing Floating Point Numbers, 2012 Edition]
    // (https://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/)
    macro_rules! impl_relative_eq {
        ($T:ident, $U:ident) => {
            impl RelativeEq for $T {
                #[inline]
                fn default_max_relative() -> $T {
                    $T::EPSILON
                }

                #[inline]
                #[allow(unused_imports)]
                fn relative_eq(&self, other: &$T, epsilon: $T, max_relative: $T) -> bool {
                    use num_traits::float::FloatCore;
                    // Handle same infinities
                    if self == other {
                        return true;
                    }

                    // Handle remaining infinities
                    if $T::is_infinite(*self) || $T::is_infinite(*other) {
                        return false;
                    }

                    let abs_diff = $T::abs(self - other);

                    // For when the numbers are really close together
                    if abs_diff <= epsilon {
                        return true;
                    }

                    let abs_self = $T::abs(*self);
                    let abs_other = $T::abs(*other);

                    let largest = if abs_other > abs_self {
                        abs_other
                    } else {
                        abs_self
                    };

                    // Use a relative difference comparison
                    abs_diff <= largest * max_relative
                }
            }
        };
    }

    impl_relative_eq!(f32, i32);
    impl_relative_eq!(f64, i64);

    ///////////////////////////////////////////////////////////////////////////////////////////////////
    // Derived implementations
    ///////////////////////////////////////////////////////////////////////////////////////////////////

    impl<'a, T: RelativeEq + ?Sized> RelativeEq for &'a T {
        #[inline]
        fn default_max_relative() -> T::Epsilon {
            T::default_max_relative()
        }

        #[inline]
        fn relative_eq(&self, other: &&'a T, epsilon: T::Epsilon, max_relative: T::Epsilon) -> bool {
            T::relative_eq(*self, *other, epsilon, max_relative)
        }
    }

    impl<'a, T: RelativeEq + ?Sized> RelativeEq for &'a mut T {
        #[inline]
        fn default_max_relative() -> T::Epsilon {
            T::default_max_relative()
        }

        #[inline]
        fn relative_eq(
            &self,
            other: &&'a mut T,
            epsilon: T::Epsilon,
            max_relative: T::Epsilon,
        ) -> bool {
            T::relative_eq(*self, *other, epsilon, max_relative)
        }
    }

    impl<T: RelativeEq + Copy> RelativeEq for cell::Cell<T> {
        #[inline]
        fn default_max_relative() -> T::Epsilon {
            T::default_max_relative()
        }

        #[inline]
        fn relative_eq(
            &self,
            other: &cell::Cell<T>,
            epsilon: T::Epsilon,
            max_relative: T::Epsilon,
        ) -> bool {
            T::relative_eq(&self.get(), &other.get(), epsilon, max_relative)
        }
    }

    impl<T: RelativeEq + ?Sized> RelativeEq for cell::RefCell<T> {
        #[inline]
        fn default_max_relative() -> T::Epsilon {
            T::default_max_relative()
        }

        #[inline]
        fn relative_eq(
            &self,
            other: &cell::RefCell<T>,
            epsilon: T::Epsilon,
            max_relative: T::Epsilon,
        ) -> bool {
            T::relative_eq(&self.borrow(), &other.borrow(), epsilon, max_relative)
        }
    }

    impl<A, B> RelativeEq<[B]> for [A]
    where
        A: RelativeEq<B>,
        A::Epsilon: Clone,
    {
        #[inline]
        fn default_max_relative() -> A::Epsilon {
            A::default_max_relative()
        }

        #[inline]
        fn relative_eq(&self, other: &[B], epsilon: A::Epsilon, max_relative: A::Epsilon) -> bool {
            self.len() == other.len()
                && Iterator::zip(self.iter(), other)
                    .all(|(x, y)| A::relative_eq(x, y, epsilon.clone(), max_relative.clone()))
        }
    }

    #[cfg(feature = "num-complex")]
    impl<T: RelativeEq> RelativeEq for Complex<T>
    where
        T::Epsilon: Clone,
    {
        #[inline]
        fn default_max_relative() -> T::Epsilon {
            T::default_max_relative()
        }

        #[inline]
        fn relative_eq(
            &self,
            other: &Complex<T>,
            epsilon: T::Epsilon,
            max_relative: T::Epsilon,
        ) -> bool {
            T::relative_eq(&self.re, &other.re, epsilon.clone(), max_relative.clone())
                && T::relative_eq(&self.im, &other.im, epsilon, max_relative)
        }
    }