From 0e8b440650fffe49f1ecf591e531000ecd4440e6 Mon Sep 17 00:00:00 2001
From: Michal 'vorner' Vaner <vorner+github@vorner.cz>
Date: Wed, 6 Mar 2019 20:46:42 +0100
Subject: [PATCH] Implementation of Buf for VecDeque (#249)

---
 src/buf/mod.rs       |  1 +
 src/buf/vec_deque.rs | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)
 create mode 100644 src/buf/vec_deque.rs

diff --git a/src/buf/mod.rs b/src/buf/mod.rs
index 1f74e0ab4..35b4857ec 100644
--- a/src/buf/mod.rs
+++ b/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;
diff --git a/src/buf/vec_deque.rs b/src/buf/vec_deque.rs
new file mode 100644
index 000000000..1cd650f51
--- /dev/null
+++ b/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>>()[..]);
+    }
+}