Add unstable copy_from_slice

1 files changed, 13 insertions, 1 deletions

diff --git a/src/libcore/slice.rs b/src/libcore/slice.rs
index 40041c748e7..afda70f4fcc 100644
--- a/src/libcore/slice.rs
+++ b/src/libcore/slice.rs
@@ -48,7 +48,7 @@ use result::Result;
 use result::Result::{Ok, Err};
 use ptr;
 use mem;
-use marker::{Send, Sync, self};
+use marker::{Copy, Send, Sync, self};
 use raw::Repr;
 // Avoid conflicts with *both* the Slice trait (buggy) and the `slice::raw` module.
 use raw::Slice as RawSlice;
@@ -152,6 +152,8 @@ pub trait SliceExt {
 
     #[stable(feature = "clone_from_slice", since = "1.7.0")]
     fn clone_from_slice(&mut self, &[Self::Item]) where Self::Item: Clone;
+    #[unstable(feature = "copy_from_slice", issue = "31755")]
+    fn copy_from_slice(&mut self, src: &[Self::Item]) where Self::Item: Copy;
 }
 
 // Use macros to be generic over const/mut
@@ -488,6 +490,16 @@ impl<T> SliceExt for [T] {
             self[i].clone_from(&src[i]);
         }
     }
+
+    #[inline]
+    fn copy_from_slice(&mut self, src: &[T]) where T: Copy {
+        assert!(self.len() == src.len(),
+                "destination and source slices have different lengths");
+        unsafe {
+            ptr::copy_nonoverlapping(
+                src.as_ptr(), self.as_mut_ptr(), self.len());
+        }
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]