From 0380ba18ad23ac300565f5a2462793fdd45b6998 Mon Sep 17 00:00:00 2001
From: Jack O'Connor <oconnor663@gmail.com>
Date: Mon, 1 Oct 2018 15:23:43 -0400
Subject: [PATCH] remove the dependency on byteorder

Since that crate takes slices in its API, it tends to introduce
unnecessary bounds checks.
---
 Cargo.toml      |  1 -
 src/lib.rs      | 25 ++++++++++++++++++-------
 src/portable.rs | 23 +++++++++++++++++++----
 3 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 76d14ca..d058b66 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,7 +11,6 @@ readme = "README.md"
 [dependencies]
 arrayref = "0.3.5"
 arrayvec = { version = "0.4.7", default-features = false, features = ["use_union"] }
-byteorder = { version = "1.2.4", default-features = false }
 constant_time_eq = "0.1.3"
 rayon = { version = "1.0.2", optional = true }
 
diff --git a/src/lib.rs b/src/lib.rs
index 8ca49c1..48a06ec 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -102,6 +102,7 @@
 //! throughput of 1.8 cycles per byte.
 
 #![cfg_attr(not(feature = "std"), no_std)]
+#![feature(int_to_from_bytes)]
 
 #[cfg(feature = "std")]
 extern crate core;
@@ -109,11 +110,9 @@ extern crate core;
 #[macro_use]
 extern crate arrayref;
 extern crate arrayvec;
-extern crate byteorder;
 extern crate constant_time_eq;
 
 use arrayvec::ArrayString;
-use byteorder::{ByteOrder, LittleEndian};
 use core::cmp;
 use core::fmt;
 
@@ -372,6 +371,8 @@ impl State {
     }
 
     fn with_params(params: &Params) -> Self {
+        let salt_refs = array_refs!(&params.salt, 8, 8);
+        let personal_refs = array_refs!(&params.personal, 8, 8);
         let mut state = Self {
             h: [
                 IV[0]
@@ -383,10 +384,10 @@ impl State {
                 IV[1] ^ params.node_offset,
                 IV[2] ^ params.node_depth as u64 ^ (params.inner_hash_length as u64) << 8,
                 IV[3],
-                IV[4] ^ LittleEndian::read_u64(&params.salt[..8]),
-                IV[5] ^ LittleEndian::read_u64(&params.salt[8..]),
-                IV[6] ^ LittleEndian::read_u64(&params.personal[..8]),
-                IV[7] ^ LittleEndian::read_u64(&params.personal[8..]),
+                IV[4] ^ u64::from_le_bytes(*salt_refs.0),
+                IV[5] ^ u64::from_le_bytes(*salt_refs.1),
+                IV[6] ^ u64::from_le_bytes(*personal_refs.0),
+                IV[7] ^ u64::from_le_bytes(*personal_refs.1),
             ],
             compress_fn: default_compress_impl(),
             buf: [0; BLOCKBYTES],
@@ -459,7 +460,17 @@ impl State {
             bytes: [0; OUTBYTES],
             len: self.hash_length,
         };
-        LittleEndian::write_u64_into(&h_copy, &mut hash.bytes);
+        {
+            let bytes_refs = mut_array_refs!(&mut hash.bytes, 8, 8, 8, 8, 8, 8, 8, 8);
+            *bytes_refs.0 = h_copy[0].to_le_bytes();
+            *bytes_refs.1 = h_copy[1].to_le_bytes();
+            *bytes_refs.2 = h_copy[2].to_le_bytes();
+            *bytes_refs.3 = h_copy[3].to_le_bytes();
+            *bytes_refs.4 = h_copy[4].to_le_bytes();
+            *bytes_refs.5 = h_copy[5].to_le_bytes();
+            *bytes_refs.6 = h_copy[6].to_le_bytes();
+            *bytes_refs.7 = h_copy[7].to_le_bytes();
+        }
         hash
     }
 
diff --git a/src/portable.rs b/src/portable.rs
index 971f464..78193ec 100644
--- a/src/portable.rs
+++ b/src/portable.rs
@@ -1,5 +1,3 @@
-use byteorder::{ByteOrder, LittleEndian};
-
 use Block;
 use StateWords;
 use IV;
@@ -81,8 +79,25 @@ pub fn compress(h: &mut StateWords, msg: &Block, count: u128, lastblock: u64, la
     ];
 
     // Parse the message bytes as ints in little endian order.
-    let mut m = [0; 16];
-    LittleEndian::read_u64_into(msg, &mut m);
+    let msg_refs = array_refs!(msg, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8);
+    let m = [
+        u64::from_le_bytes(*msg_refs.0),
+        u64::from_le_bytes(*msg_refs.1),
+        u64::from_le_bytes(*msg_refs.2),
+        u64::from_le_bytes(*msg_refs.3),
+        u64::from_le_bytes(*msg_refs.4),
+        u64::from_le_bytes(*msg_refs.5),
+        u64::from_le_bytes(*msg_refs.6),
+        u64::from_le_bytes(*msg_refs.7),
+        u64::from_le_bytes(*msg_refs.8),
+        u64::from_le_bytes(*msg_refs.9),
+        u64::from_le_bytes(*msg_refs.10),
+        u64::from_le_bytes(*msg_refs.11),
+        u64::from_le_bytes(*msg_refs.12),
+        u64::from_le_bytes(*msg_refs.13),
+        u64::from_le_bytes(*msg_refs.14),
+        u64::from_le_bytes(*msg_refs.15),
+    ];
 
     round(0, &m, &mut v);
     round(1, &m, &mut v);