From 901dc2c15e08b6527f084c211d8d93448d997155 Mon Sep 17 00:00:00 2001
From: Shamir Khodzha <khodzha.sh@gmail.com>
Date: Sat, 11 Jan 2014 14:13:06 +0400
Subject: [PATCH] added empty() to Peekable

---
 src/libstd/iter.rs | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/libstd/iter.rs b/src/libstd/iter.rs
index 2056f8b33ec1..b9d7ee82851e 100644
--- a/src/libstd/iter.rs
+++ b/src/libstd/iter.rs
@@ -1,4 +1,4 @@
-// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -1362,6 +1362,12 @@ impl<'a, A, T: Iterator<A>> Peekable<A, T> {
             None => None,
         }
     }
+
+    /// Check whether peekable iterator is empty or not.
+    #[inline]
+    pub fn empty(&mut self) -> bool {
+        self.peek().is_some()
+    }
 }
 
 /// An iterator which rejects elements while `predicate` is true
@@ -2923,4 +2929,12 @@ mod tests {
         ys.mut_iter().reverse_();
         assert_eq!(ys, [5, 4, 3, 2, 1]);
     }
+
+    fn test_peekable_empty() {
+        let a = [1];
+        let mut it = a.iter().peekable();
+        assert!( !it.empty() );
+        it.next();
+        assert!( it.empty() );
+    }
 }