Auto merge of #279 - yoanlcq:impl-num-for-wrapping, r=cuviper

Implemented Zero, One and Num for std::num::Wrapping<T>

Attempts to fix issue #278

Author: homu

traits/src/identities.rs

@@ -1,4 +1,5 @@
 use std::ops::{Add, Mul};
+use std::num::Wrapping;
 
 /// Defines an additive identity element for `Self`.
 pub trait Zero: Sized + Add<Self, Output = Self> {
@@ -50,6 +51,16 @@ zero_impl!(i64,   0i64);
 zero_impl!(f32, 0.0f32);
 zero_impl!(f64, 0.0f64);
 
+impl<T: Zero> Zero for Wrapping<T> where Wrapping<T>: Add<Output=Wrapping<T>> {
+    fn is_zero(&self) -> bool {
+        self.0.is_zero()
+    }
+    fn zero() -> Self {
+        Wrapping(T::zero())
+    }
+}
+
+
 /// Defines a multiplicative identity element for `Self`.
 pub trait One: Sized + Mul<Self, Output = Self> {
     /// Returns the multiplicative identity element of `Self`, `1`.
@@ -94,6 +105,11 @@ one_impl!(i64,   1i64);
 one_impl!(f32, 1.0f32);
 one_impl!(f64, 1.0f64);
 
+impl<T: One> One for Wrapping<T> where Wrapping<T>: Mul<Output=Wrapping<T>> {
+    fn one() -> Self {
+        Wrapping(T::one())
+    }
+}
 
 // Some helper functions provided for backwards compatibility.
 

traits/src/lib.rs

@@ -15,6 +15,7 @@
        html_playground_url = "http://play.integer32.com/")]
 
 use std::ops::{Add, Sub, Mul, Div, Rem};
+use std::num::Wrapping;
 
 pub use bounds::Bounded;
 pub use float::{Float, FloatConst};
@@ -74,6 +75,18 @@ macro_rules! int_trait_impl {
 }
 int_trait_impl!(Num for usize u8 u16 u32 u64 isize i8 i16 i32 i64);
 
+impl<T: Num> Num for Wrapping<T>
+    where Wrapping<T>:
+          Add<Output = Wrapping<T>> + Sub<Output = Wrapping<T>>
+        + Mul<Output = Wrapping<T>> + Div<Output = Wrapping<T>> + Rem<Output = Wrapping<T>>
+{
+    type FromStrRadixErr = T::FromStrRadixErr;
+    fn from_str_radix(str: &str, radix: u32) -> Result<Self, Self::FromStrRadixErr> {
+        T::from_str_radix(str, radix).map(Wrapping)
+    }
+}
+
+
 #[derive(Debug)]
 pub enum FloatErrorKind {
     Empty,
@@ -243,9 +256,9 @@ float_trait_impl!(Num for f32 f64);
 
 /// A value bounded by a minimum and a maximum
 ///
-///  If input is less than min then this returns min. 
-///  If input is greater than max then this returns max.  
-///  Otherwise this returns input. 
+///  If input is less than min then this returns min.
+///  If input is greater than max then this returns max.
+///  Otherwise this returns input.
 #[inline]
 pub fn clamp<T: PartialOrd>(input: T, min: T, max: T) -> T {
     debug_assert!(min <= max, "min must be less than or equal to max");