Implement chain combinator for Buf

tests/test_chain.rs

@@ -0,0 +1,93 @@
+extern crate bytes;
+extern crate iovec;
+
+use bytes::{Buf, BufMut, Bytes, BytesMut};
+use bytes::buf::Chain;
+use iovec::IoVec;
+use std::io::Cursor;
+
+#[test]
+fn collect_two_bufs() {
+    let a = Cursor::new(Bytes::from(&b"hello"[..]));
+    let b = Cursor::new(Bytes::from(&b"world"[..]));
+
+    let res: Vec<u8> = a.chain(b).collect();
+    assert_eq!(res, &b"helloworld"[..]);
+}
+
+#[test]
+fn writing_chained() {
+    let mut a = BytesMut::with_capacity(64);
+    let mut b = BytesMut::with_capacity(64);
+
+    {
+        let mut buf = Chain::new(&mut a, &mut b);
+
+        for i in 0..128 {
+            buf.put(i as u8);
+        }
+    }
+
+    assert_eq!(64, a.len());
+    assert_eq!(64, b.len());
+
+    for i in 0..64 {
+        let expect = i as u8;
+        assert_eq!(expect, a[i]);
+        assert_eq!(expect + 64, b[i]);
+    }
+}
+
+#[test]
+fn iterating_two_bufs() {
+    let a = Cursor::new(Bytes::from(&b"hello"[..]));
+    let b = Cursor::new(Bytes::from(&b"world"[..]));
+
+    let res: Vec<u8> = a.chain(b).iter().collect();
+    assert_eq!(res, &b"helloworld"[..]);
+}
+
+#[test]
+fn vectored_read() {
+    let a = Cursor::new(Bytes::from(&b"hello"[..]));
+    let b = Cursor::new(Bytes::from(&b"world"[..]));
+
+    let mut buf = a.chain(b);
+    let mut iovecs: [&IoVec; 4] = Default::default();
+
+    assert_eq!(2, buf.bytes_vec(&mut iovecs));
+    assert_eq!(iovecs[0][..], b"hello"[..]);
+    assert_eq!(iovecs[1][..], b"world"[..]);
+    assert!(iovecs[2].is_empty());
+    assert!(iovecs[3].is_empty());
+
+    buf.advance(2);
+
+    iovecs = Default::default();
+
+    assert_eq!(2, buf.bytes_vec(&mut iovecs));
+    assert_eq!(iovecs[0][..], b"llo"[..]);
+    assert_eq!(iovecs[1][..], b"world"[..]);
+    assert!(iovecs[2].is_empty());
+    assert!(iovecs[3].is_empty());
+
+    buf.advance(3);
+
+    iovecs = Default::default();
+
+    assert_eq!(1, buf.bytes_vec(&mut iovecs));
+    assert_eq!(iovecs[0][..], b"world"[..]);
+    assert!(iovecs[1].is_empty());
+    assert!(iovecs[2].is_empty());
+    assert!(iovecs[3].is_empty());
+
+    buf.advance(3);
+
+    iovecs = Default::default();
+
+    assert_eq!(1, buf.bytes_vec(&mut iovecs));
+    assert_eq!(iovecs[0][..], b"ld"[..]);
+    assert!(iovecs[1].is_empty());
+    assert!(iovecs[2].is_empty());
+    assert!(iovecs[3].is_empty());
+}