bounds.rs - source
Description: Source of the Rust file `/Users/erlendbasso/.cargo/registry/src/github.com-1ecc6299db9ec823/num-traits-0.2.15/src/bounds.rs`.
Keywords: rust, rustlang, rust-lang

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    use core::num::Wrapping;
    use core::{f32, f64};
    #[cfg(has_i128)]
    use core::{i128, u128};
    use core::{i16, i32, i64, i8, isize};
    use core::{u16, u32, u64, u8, usize};

    /// Numbers which have upper and lower bounds
    pub trait Bounded {
        // FIXME (#5527): These should be associated constants
        /// Returns the smallest finite number this type can represent
        fn min_value() -> Self;
        /// Returns the largest finite number this type can represent
        fn max_value() -> Self;
    }

    /// Numbers which have lower bounds
    pub trait LowerBounded {
        /// Returns the smallest finite number this type can represent
        fn min_value() -> Self;
    }

    // FIXME: With a major version bump, this should be a supertrait instead
    impl<T: Bounded> LowerBounded for T {
        fn min_value() -> T {
            Bounded::min_value()
        }
    }

    /// Numbers which have upper bounds
    pub trait UpperBounded {
        /// Returns the largest finite number this type can represent
        fn max_value() -> Self;
    }

    // FIXME: With a major version bump, this should be a supertrait instead
    impl<T: Bounded> UpperBounded for T {
        fn max_value() -> T {
            Bounded::max_value()
        }
    }

    macro_rules! bounded_impl {
        ($t:ty, $min:expr, $max:expr) => {
            impl Bounded for $t {
                #[inline]
                fn min_value() -> $t {
                    $min
                }

                #[inline]
                fn max_value() -> $t {
                    $max
                }
            }
        };
    }

    bounded_impl!(usize, usize::MIN, usize::MAX);
    bounded_impl!(u8, u8::MIN, u8::MAX);
    bounded_impl!(u16, u16::MIN, u16::MAX);
    bounded_impl!(u32, u32::MIN, u32::MAX);
    bounded_impl!(u64, u64::MIN, u64::MAX);
    #[cfg(has_i128)]
    bounded_impl!(u128, u128::MIN, u128::MAX);

    bounded_impl!(isize, isize::MIN, isize::MAX);
    bounded_impl!(i8, i8::MIN, i8::MAX);
    bounded_impl!(i16, i16::MIN, i16::MAX);
    bounded_impl!(i32, i32::MIN, i32::MAX);
    bounded_impl!(i64, i64::MIN, i64::MAX);
    #[cfg(has_i128)]
    bounded_impl!(i128, i128::MIN, i128::MAX);

    impl<T: Bounded> Bounded for Wrapping<T> {
        fn min_value() -> Self {
            Wrapping(T::min_value())
        }
        fn max_value() -> Self {
            Wrapping(T::max_value())
        }
    }

    bounded_impl!(f32, f32::MIN, f32::MAX);

    macro_rules! for_each_tuple_ {
        ( $m:ident !! ) => (
            $m! { }
        );
        ( $m:ident !! $h:ident, $($t:ident,)* ) => (
            $m! { $h $($t)* }
            for_each_tuple_! { $m !! $($t,)* }
        );
    }
    macro_rules! for_each_tuple {
        ($m:ident) => {
            for_each_tuple_! { $m !! A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, }
        };
    }

    macro_rules! bounded_tuple {
        ( $($name:ident)* ) => (
            impl<$($name: Bounded,)*> Bounded for ($($name,)*) {
                #[inline]
                fn min_value() -> Self {
                    ($($name::min_value(),)*)
                }
                #[inline]
                fn max_value() -> Self {
                    ($($name::max_value(),)*)
                }
            }
        );
    }

    for_each_tuple!(bounded_tuple);
    bounded_impl!(f64, f64::MIN, f64::MAX);

    #[test]
    fn wrapping_bounded() {
        macro_rules! test_wrapping_bounded {
            ($($t:ty)+) => {
                $(
                    assert_eq!(<Wrapping<$t> as Bounded>::min_value().0, <$t>::min_value());
                    assert_eq!(<Wrapping<$t> as Bounded>::max_value().0, <$t>::max_value());
                )+
            };
        }

        test_wrapping_bounded!(usize u8 u16 u32 u64 isize i8 i16 i32 i64);
    }

    #[cfg(has_i128)]
    #[test]
    fn wrapping_bounded_i128() {
        macro_rules! test_wrapping_bounded {
            ($($t:ty)+) => {
                $(
                    assert_eq!(<Wrapping<$t> as Bounded>::min_value().0, <$t>::min_value());
                    assert_eq!(<Wrapping<$t> as Bounded>::max_value().0, <$t>::max_value());
                )+
            };
        }

        test_wrapping_bounded!(u128 i128);
    }

    #[test]
    fn wrapping_is_bounded() {
        fn require_bounded<T: Bounded>(_: &T) {}
        require_bounded(&Wrapping(42_u32));
        require_bounded(&Wrapping(-42));
    }