1 files changed, 153 insertions, 0 deletions
diff --git a/third_party/rust/num-traits/src/bounds.rs b/third_party/rust/num-traits/src/bounds.rs
new file mode 100644
index 0000000000..36e1bbdfb0
--- /dev/null
+++ b/third_party/rust/num-traits/src/bounds.rs
@@ -0,0 +1,153 @@
+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));
+}