From ad35fbef035da3bc0b18b2042ae19cf7358fec6e Mon Sep 17 00:00:00 2001
From: Carl Lerche <me@carllerche.com>
Date: Mon, 3 Sep 2018 10:23:00 -0700
Subject: [PATCH] implement `Buf` and `BufMut` for `Either` (#225)

---
 .travis.yml   |  3 ++
 Cargo.toml    |  1 +
 src/either.rs | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs    |  4 +++
 4 files changed, 97 insertions(+)
 create mode 100644 src/either.rs

diff --git a/.travis.yml b/.travis.yml
index 3deb61f..2e8ab18 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -39,6 +39,9 @@ matrix:
     # 128 bit numbers
     - env: EXTRA_ARGS="--features i128"
 
+    # `Either` impls
+    - env: EXTRA_ARGS="--features either"
+
     # WASM support
     - rust: beta
       script:
diff --git a/Cargo.toml b/Cargo.toml
index 9cfed61..af9a794 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -26,6 +26,7 @@ features = ["i128"]
 byteorder = "1.1.0"
 iovec = "0.1"
 serde = { version = "1.0", optional = true }
+either = { version = "1.5", default-features = false, optional = true }
 
 [dev-dependencies]
 serde_test = "1.0"
diff --git a/src/either.rs b/src/either.rs
new file mode 100644
index 0000000..53a2775
--- /dev/null
+++ b/src/either.rs
@@ -0,0 +1,89 @@
+extern crate either;
+
+use {Buf, BufMut};
+
+use self::either::Either;
+use self::either::Either::*;
+use iovec::IoVec;
+
+impl<L, R> Buf for Either<L, R>
+where
+    L: Buf,
+    R: Buf,
+{
+    fn remaining(&self) -> usize {
+        match *self {
+            Left(ref b) => b.remaining(),
+            Right(ref b) => b.remaining(),
+        }
+    }
+
+    fn bytes(&self) -> &[u8] {
+        match *self {
+            Left(ref b) => b.bytes(),
+            Right(ref b) => b.bytes(),
+        }
+    }
+
+    fn bytes_vec<'a>(&'a self, dst: &mut [&'a IoVec]) -> usize {
+        match *self {
+            Left(ref b) => b.bytes_vec(dst),
+            Right(ref b) => b.bytes_vec(dst),
+        }
+    }
+
+    fn advance(&mut self, cnt: usize) {
+        match *self {
+            Left(ref mut b) => b.advance(cnt),
+            Right(ref mut b) => b.advance(cnt),
+        }
+    }
+
+    fn copy_to_slice(&mut self, dst: &mut [u8]) {
+        match *self {
+            Left(ref mut b) => b.copy_to_slice(dst),
+            Right(ref mut b) => b.copy_to_slice(dst),
+        }
+    }
+}
+
+impl<L, R> BufMut for Either<L, R>
+where
+    L: BufMut,
+    R: BufMut,
+{
+    fn remaining_mut(&self) -> usize {
+        match *self {
+            Left(ref b) => b.remaining_mut(),
+            Right(ref b) => b.remaining_mut(),
+        }
+    }
+
+    unsafe fn bytes_mut(&mut self) -> &mut [u8] {
+        match *self {
+            Left(ref mut b) => b.bytes_mut(),
+            Right(ref mut b) => b.bytes_mut(),
+        }
+    }
+
+    unsafe fn bytes_vec_mut<'a>(&'a mut self, dst: &mut [&'a mut IoVec]) -> usize {
+        match *self {
+            Left(ref mut b) => b.bytes_vec_mut(dst),
+            Right(ref mut b) => b.bytes_vec_mut(dst),
+        }
+    }
+
+    unsafe fn advance_mut(&mut self, cnt: usize) {
+        match *self {
+            Left(ref mut b) => b.advance_mut(cnt),
+            Right(ref mut b) => b.advance_mut(cnt),
+        }
+    }
+
+    fn put_slice(&mut self, src: &[u8]) {
+        match *self {
+            Left(ref mut b) => b.put_slice(src),
+            Right(ref mut b) => b.put_slice(src),
+        }
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index eccb8a3..b007940 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -99,3 +99,7 @@ pub use byteorder::{ByteOrder, BigEndian, LittleEndian};
 #[cfg(feature = "serde")]
 #[doc(hidden)]
 pub mod serde;
+
+// Optional `Either` support
+#[cfg(feature = "either")]
+mod either;