Add Saturating type (based on Wrapping type)

library/core/src/num/int_macros.rs

@@ -926,21 +926,34 @@ macro_rules! int_impl {
         /// Basic usage:
         ///
         /// ```
+        /// #![feature(saturating_div)]
+        ///
+        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_div(-1), ", stringify!($SelfT), "::MIN + 1);")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_div(-1), ", stringify!($SelfT), "::MAX);")]
         ///
         /// ```
-        #[unstable(feature = "saturating_int_impl", issue = "87920")]
-        #[rustc_const_unstable(feature = "saturating_int_impl", issue = "87920")]
+        ///
+        /// ```should_panic
+        /// #![feature(saturating_div)]
+        ///
+        #[doc = concat!("let _ = 1", stringify!($SelfT), ".saturating_div(0);")]
+        ///
+        /// ```
+        #[unstable(feature = "saturating_div", issue = "87920")]
+        #[rustc_const_unstable(feature = "saturating_div", issue = "87920")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
         pub const fn saturating_div(self, rhs: Self) -> Self {
-            match self.checked_div(rhs) {
-                Some(x) => x,
-                None => if (self < 0) == (rhs < 0) {
-                    Self::MAX
-                } else {
-                    Self::MIN
-                }
+            let (result, overflowed) = self.overflowing_div(rhs);
+
+            if !overflowed {
+                result
+            } else if (self < 0) == (rhs < 0) {
+                Self::MAX
+            } else {
+                Self::MIN
             }
         }
 

library/core/src/num/saturating.rs

@@ -266,6 +266,37 @@ macro_rules! saturating_impl {
         }
         forward_ref_op_assign! { impl MulAssign, mul_assign for Saturating<$t>, Saturating<$t> }
 
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// #![feature(saturating_int_impl, saturating_div)]
+        /// use std::num::Saturating;
+        ///
+        #[doc = concat!("assert_eq!(Saturating(2", stringify!($t), "), Saturating(5", stringify!($t), ") / Saturating(2));")]
+        #[doc = concat!("assert_eq!(Saturating(", stringify!($t), "::MAX), Saturating(", stringify!($t), "::MAX) / Saturating(1));")]
+        #[doc = concat!("assert_eq!(Saturating(", stringify!($t), "::MIN), Saturating(", stringify!($t), "::MIN) / Saturating(1));")]
+        /// ```
+        ///
+        /// ```should_panic
+        /// #![feature(saturating_int_impl, saturating_div)]
+        /// use std::num::Saturating;
+        ///
+        #[doc = concat!("let _ = Saturating(0", stringify!($t), ") / Saturating(0);")]
+        /// ```
+        #[unstable(feature = "saturating_int_impl", issue = "87920")]
+        impl Div for Saturating<$t> {
+            type Output = Saturating<$t>;
+
+            #[inline]
+            fn div(self, other: Saturating<$t>) -> Saturating<$t> {
+                Saturating(self.0.saturating_div(other.0))
+            }
+        }
+        forward_ref_binop! { impl Div, div for Saturating<$t>, Saturating<$t>,
+                #[unstable(feature = "saturating_int_impl", issue = "87920")] }
+
         #[unstable(feature = "saturating_int_impl", issue = "87920")]
         impl DivAssign for Saturating<$t> {
             #[inline]
@@ -851,31 +882,6 @@ macro_rules! saturating_int_impl_signed {
         }
         forward_ref_unop! { impl Neg, neg for Saturating<$t>,
                 #[unstable(feature = "saturating_int_impl", issue = "87920")] }
-
-        /// # Examples
-        ///
-        /// Basic usage:
-        ///
-        /// ```
-        /// #![feature(saturating_int_impl)]
-        /// use std::num::Saturating;
-        ///
-        #[doc = concat!("assert_eq!(Saturating(", stringify!($t), "::MIN + 1), Saturating(", stringify!($t), "::MAX) / Saturating(-1));")]
-        #[doc = concat!("assert_eq!(Saturating(", stringify!($t), "::MAX), Saturating(", stringify!($t), "::MIN) / Saturating(-1));")]
-        #[doc = concat!("assert_eq!(Saturating(", stringify!($t), "::MAX), Saturating(", stringify!($t), "::MAX) / Saturating(1));")]
-        #[doc = concat!("assert_eq!(Saturating(", stringify!($t), "::MIN), Saturating(", stringify!($t), "::MIN) / Saturating(1));")]
-        /// ```
-        #[unstable(feature = "saturating_int_impl", issue = "87920")]
-        impl Div for Saturating<$t> {
-            type Output = Saturating<$t>;
-
-            #[inline]
-            fn div(self, other: Saturating<$t>) -> Saturating<$t> {
-                Saturating(self.0.saturating_div(other.0))
-            }
-        }
-        forward_ref_binop! { impl Div, div for Saturating<$t>, Saturating<$t>,
-                #[unstable(feature = "saturating_int_impl", issue = "87920")] }
     )*)
 }
 
@@ -924,18 +930,6 @@ macro_rules! saturating_int_impl_unsigned {
             }
 
         }
-
-        #[unstable(feature = "saturating_int_impl", issue = "87920")]
-        impl Div for Saturating<$t> {
-            type Output = Saturating<$t>;
-
-            #[inline]
-            fn div(self, other: Saturating<$t>) -> Saturating<$t> {
-                Saturating(self.0.div(other.0))
-            }
-        }
-        forward_ref_binop! { impl Div, div for Saturating<$t>, Saturating<$t>,
-                #[unstable(feature = "saturating_int_impl", issue = "87920")] }
     )*)
 }
 

library/core/src/num/uint_macros.rs

@@ -1041,6 +1041,36 @@ macro_rules! uint_impl {
             }
         }
 
+        /// Saturating integer division. Computes `self / rhs`, saturating at the
+        /// numeric bounds instead of overflowing.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// #![feature(saturating_div)]
+        ///
+        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
+        ///
+        /// ```
+        ///
+        /// ```should_panic
+        /// #![feature(saturating_div)]
+        ///
+        #[doc = concat!("let _ = 1", stringify!($SelfT), ".saturating_div(0);")]
+        ///
+        /// ```
+        #[unstable(feature = "saturating_div", issue = "87920")]
+        #[rustc_const_unstable(feature = "saturating_div", issue = "87920")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn saturating_div(self, rhs: Self) -> Self {
+            // on unsigned types, there is no overflow in integer division
+            self.wrapping_div(rhs)
+        }
+
         /// Saturating integer exponentiation. Computes `self.pow(exp)`,
         /// saturating at the numeric bounds instead of overflowing.
         ///

library/std/src/lib.rs

@@ -308,6 +308,7 @@
 #![feature(ptr_internals)]
 #![feature(rustc_attrs)]
 #![feature(rustc_private)]
+#![feature(saturating_div)]
 #![feature(saturating_int_impl)]
 #![feature(slice_concat_ext)]
 #![feature(slice_internals)]