Merge pull request #12 from tbu-/pr_write

Add `io::Write` implementation akin to `Vec`

src/lib.rs

@@ -2,6 +2,7 @@ extern crate odds;
 extern crate nodrop;
 
 use std::cmp;
+use std::io;
 use std::iter;
 use std::mem;
 use std::ptr;
@@ -675,3 +676,19 @@ impl<A: Array> Ord for ArrayVec<A> where A::Item: Ord {
         (**self).cmp(other)
     }
 }
+
+impl<A: Array<Item=u8>> io::Write for ArrayVec<A> {
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        unsafe {
+            let len = self.len();
+            let mut tail = slice::from_raw_parts_mut(self.get_unchecked_mut(len),
+                                                     A::capacity() - len);
+            let result = tail.write(data);
+            if let Ok(written) = result {
+                self.set_len(len + written);
+            }
+            result
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}