Merge #201

201: support u128 r=Dylan-DPC a=kinggoesgaming

**I'm submitting a ...**
  - [ ] bug fix
  - [x] feature enhancement
  - [ ] deprecation or removal
  - [ ] refactor

# Description
* features introduced: `u128`, `nightly`
* rust channel needed: `nightly`
* dependency introduced: `byteorder`

This introduced implementation for `u128` in the from of a `Uuid::from_u128` and `impl From`

# Motivation
`Uuid`s are 128 bits in size and rust natively provides a `u128` integer type. This 

# Tests
`u128_support::test_from_u128()` introduced and passes

# Related Issue(s)
N/A

Co-authored-by: Hunar Roop Kahlon <hunar.roop@gmail.com>

.travis.yml

@@ -16,6 +16,9 @@ matrix:
     - rust: beta
     - rust: nightly
 
+    - rust: nightly
+      env: FEATURES="u128"
+
     - rust: nightly
       script: cargo bench --all-features
 

Cargo.toml

@@ -27,14 +27,17 @@ sha1 = { version = "0.6", optional = true }
 md5 = { version = "0.3", optional = true }
 slog = { version = "2", optional = true }
 cfg-if = "0.1"
+byteorder = { version = "1", optional = true, default-features = false, features = ["i128"]}
 
 [dev-dependencies]
 serde_test = "1.0.19"
 
 [features]
 default = ["std"]
+nightly = []
 std = []
 use_std = ["std"] # Compatibility shim for 0.5 and earlier
+u128 = ["nightly"]
 v1 = []
 v3 = ["md5", "rand"]
 v4 = ["rand"]

src/lib.rs

@@ -111,10 +111,17 @@
 )]
 #![deny(warnings)]
 #![cfg_attr(not(feature = "std"), no_std)]
+#![cfg_attr(all(feature = "u128", nightly), feature(i128_type))]
 
 #[macro_use]
 extern crate cfg_if;
 
+cfg_if! {
+    if #[cfg(feature = "byteorder")] {
+        extern crate byteorder;
+    }
+}
+
 cfg_if! {
     if #[cfg(feature = "md5")] {
         extern crate md5;
@@ -193,6 +200,12 @@ cfg_if! {
     }
 }
 
+cfg_if! {
+    if #[cfg(all(feature = "u128"), nightly)] {
+        mod u128_support;
+    }
+}
+
 cfg_if! {
     if #[cfg(feature = "v4")] {
         mod v4;

src/u128_support.rs

@@ -0,0 +1,46 @@
+use byteorder;
+use prelude::*;
+
+impl Uuid {
+    /// Creates a new [`Uuid`] from a `u128` value.
+    ///
+    /// To create a [`Uuid`] from `u128`s, you need `u128` feature enabled for this crate.
+    ///
+    /// [`Uuid`]: ../struct.Uuid.html
+    #[inline(always)]
+    pub fn from_u128(quad: u128) -> Self {
+        Uuid::from(quad)
+    }
+}
+
+impl From<u128> for Uuid {
+    fn from(f: u128) -> Self {
+        let mut uuid = Uuid::default();
+
+        {
+            use byteorder::ByteOrder;
+
+            byteorder::NativeEndian::write_u128(&mut uuid.bytes.as_mut(), f);
+        }
+
+        uuid
+    }
+}
+
+
+#[cfg(test)]
+mod tests {
+    use prelude::*;
+
+    #[test]
+    fn test_from_u128() {
+        const U128: u128 = 0x3a0724b4_93a0_4d87_ac28_759c6caa13c4;
+
+        let uuid = Uuid::from(U128);
+
+        let uuid2: Uuid = U128.into();
+
+        assert_eq!(uuid, uuid2)
+    }
+
+}