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Add impls for &Wrapping. Also Sum, Product impls for both Wrapping and &Wrapping. #37356

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merged 2 commits into from
Nov 5, 2016
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Add impls for &Wrapping. Also Sum, Product impls for both Wrapping and &Wrapping. #37356

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f69cd1b
Implement ops on `&Wrapping<T>`
cristicbz Oct 23, 2016
df0e5a9
Add `Sum` and `Product` impls for `Wrapping`
cristicbz Oct 22, 2016
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17 changes: 11 additions & 6 deletions src/libcore/iter/traits.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use ops::{Mul, Add};
use num::Wrapping;

/// Conversion from an `Iterator`.
///
Expand Down Expand Up @@ -584,35 +585,39 @@ pub trait Product<A = Self>: Sized {

// NB: explicitly use Add and Mul here to inherit overflow checks
macro_rules! integer_sum_product {
($($a:ident)*) => ($(
(@impls $zero:expr, $one:expr, $($a:ty)*) => ($(
#[stable(feature = "iter_arith_traits", since = "1.12.0")]
impl Sum for $a {
fn sum<I: Iterator<Item=$a>>(iter: I) -> $a {
iter.fold(0, Add::add)
iter.fold($zero, Add::add)
}
}

#[stable(feature = "iter_arith_traits", since = "1.12.0")]
impl Product for $a {
fn product<I: Iterator<Item=$a>>(iter: I) -> $a {
iter.fold(1, Mul::mul)
iter.fold($one, Mul::mul)
}
}

#[stable(feature = "iter_arith_traits", since = "1.12.0")]
impl<'a> Sum<&'a $a> for $a {
fn sum<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
iter.cloned().fold(0, Add::add)
iter.fold($zero, Add::add)
}
}

#[stable(feature = "iter_arith_traits", since = "1.12.0")]
impl<'a> Product<&'a $a> for $a {
fn product<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
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The cloned stuff is not necessary (and wasn't before) since Add::add etc are implemented for references of primitives (as well as, now, Wrapping).

iter.cloned().fold(1, Mul::mul)
iter.fold($one, Mul::mul)
}
}
)*)
)*);
($($a:ty)*) => (
integer_sum_product!(@impls 0, 1, $($a)+);
integer_sum_product!(@impls Wrapping(0), Wrapping(1), $(Wrapping<$a>)+);
);
}

macro_rules! float_sum_product {
Expand Down