Implementation of Buf for VecDeque (#249)

src/buf/mod.rs

@@ -24,6 +24,7 @@ mod into_buf;
 mod iter;
 mod reader;
 mod take;
+mod vec_deque;
 mod writer;
 
 pub use self::buf::Buf;

src/buf/vec_deque.rs

@@ -0,0 +1,39 @@
+use std::collections::VecDeque;
+
+use super::Buf;
+
+impl Buf for VecDeque<u8> {
+    fn remaining(&self) -> usize {
+        self.len()
+    }
+
+    fn bytes(&self) -> &[u8] {
+        let (s1, s2) = self.as_slices();
+        if s1.is_empty() {
+            s2
+        } else {
+            s1
+        }
+    }
+
+    fn advance(&mut self, cnt: usize) {
+        self.drain(..cnt);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn hello_world() {
+        let mut buffer: VecDeque<u8> = VecDeque::new();
+        buffer.extend(b"hello world");
+        assert_eq!(11, buffer.remaining());
+        assert_eq!(b"hello world", buffer.bytes());
+        buffer.advance(6);
+        assert_eq!(b"world", buffer.bytes());
+        buffer.extend(b" piece");
+        assert_eq!(b"world piece" as &[u8], &buffer.collect::<Vec<u8>>()[..]);
+    }
+}