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

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    use core::cell;
    #[cfg(feature = "num-complex")]
    use num_complex::Complex;

    /// Equality that is defined using the absolute difference of two numbers.
    pub trait AbsDiffEq<Rhs = Self>: PartialEq<Rhs>
    where
        Rhs: ?Sized,
    {
        /// Used for specifying relative comparisons.
        type Epsilon;

        /// The default tolerance to use when testing values that are close together.
        ///
        /// This is used when no `epsilon` value is supplied to the [`abs_diff_eq!`], [`relative_eq!`],
        /// or [`ulps_eq!`] macros.
        fn default_epsilon() -> Self::Epsilon;

        /// A test for equality that uses the absolute difference to compute the approximate
        /// equality of two numbers.
        fn abs_diff_eq(&self, other: &Rhs, epsilon: Self::Epsilon) -> bool;

        /// The inverse of [`AbsDiffEq::abs_diff_eq`].
        fn abs_diff_ne(&self, other: &Rhs, epsilon: Self::Epsilon) -> bool {
            !Self::abs_diff_eq(self, other, epsilon)
        }
    }

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

    macro_rules! impl_unsigned_abs_diff_eq {
        ($T:ident, $default_epsilon:expr) => {
            impl AbsDiffEq for $T {
                type Epsilon = $T;

                #[inline]
                fn default_epsilon() -> $T {
                    $default_epsilon
                }

                #[inline]
                fn abs_diff_eq(&self, other: &$T, epsilon: $T) -> bool {
                    (if self > other {
                        self - other
                    } else {
                        other - self
                    }) <= epsilon
                }
            }
        };
    }

    impl_unsigned_abs_diff_eq!(u8, 0);
    impl_unsigned_abs_diff_eq!(u16, 0);
    impl_unsigned_abs_diff_eq!(u32, 0);
    impl_unsigned_abs_diff_eq!(u64, 0);
    impl_unsigned_abs_diff_eq!(usize, 0);

    macro_rules! impl_signed_abs_diff_eq {
        ($T:ident, $default_epsilon:expr) => {
            impl AbsDiffEq for $T {
                type Epsilon = $T;

                #[inline]
                fn default_epsilon() -> $T {
                    $default_epsilon
                }

                #[inline]
                #[allow(unused_imports)]
                fn abs_diff_eq(&self, other: &$T, epsilon: $T) -> bool {
                    use num_traits::float::FloatCore;
                    $T::abs(self - other) <= epsilon
                }
            }
        };
    }

    impl_signed_abs_diff_eq!(i8, 0);
    impl_signed_abs_diff_eq!(i16, 0);
    impl_signed_abs_diff_eq!(i32, 0);
    impl_signed_abs_diff_eq!(i64, 0);
    impl_signed_abs_diff_eq!(isize, 0);
    impl_signed_abs_diff_eq!(f32, core::f32::EPSILON);
    impl_signed_abs_diff_eq!(f64, core::f64::EPSILON);

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

    impl<'a, T: AbsDiffEq + ?Sized> AbsDiffEq for &'a T {
        type Epsilon = T::Epsilon;

        #[inline]
        fn default_epsilon() -> T::Epsilon {
            T::default_epsilon()
        }

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

    impl<'a, T: AbsDiffEq + ?Sized> AbsDiffEq for &'a mut T {
        type Epsilon = T::Epsilon;

        #[inline]
        fn default_epsilon() -> T::Epsilon {
            T::default_epsilon()
        }

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

    impl<T: AbsDiffEq + Copy> AbsDiffEq for cell::Cell<T> {
        type Epsilon = T::Epsilon;

        #[inline]
        fn default_epsilon() -> T::Epsilon {
            T::default_epsilon()
        }

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

    impl<T: AbsDiffEq + ?Sized> AbsDiffEq for cell::RefCell<T> {
        type Epsilon = T::Epsilon;

        #[inline]
        fn default_epsilon() -> T::Epsilon {
            T::default_epsilon()
        }

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

    impl<A, B> AbsDiffEq<[B]> for [A]
    where
        A: AbsDiffEq<B>,
        A::Epsilon: Clone,
    {
        type Epsilon = A::Epsilon;

        #[inline]
        fn default_epsilon() -> A::Epsilon {
            A::default_epsilon()
        }

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

    #[cfg(feature = "num-complex")]
    impl<T: AbsDiffEq> AbsDiffEq for Complex<T>
    where
        T::Epsilon: Clone,
    {
        type Epsilon = T::Epsilon;

        #[inline]
        fn default_epsilon() -> T::Epsilon {
            T::default_epsilon()
        }

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