From 55c89a917ad616c0d7d93da0496f371aa3bb0815 Mon Sep 17 00:00:00 2001
From: shnatsel <Sergey "Shnatsel" Davidoff>
Date: Sun, 26 May 2019 15:43:31 +0200
Subject: [PATCH] Drop unsafe code from currently unsound function prefix()

This incurs at about 1% performance penalty. It can probably be avoided by using slice::windows() in flush() instead of indexing.
---
 src/lz77/default.rs | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/src/lz77/default.rs b/src/lz77/default.rs
index f11aae0..d00dd94 100644
--- a/src/lz77/default.rs
+++ b/src/lz77/default.rs
@@ -109,14 +109,9 @@ impl Lz77Encode for DefaultLz77Encoder {
 }
 
 #[inline]
-fn prefix(buf: &[u8]) -> [u8; 3] {
-    unsafe {
-        [
-            *buf.get_unchecked(0),
-            *buf.get_unchecked(1),
-            *buf.get_unchecked(2),
-        ]
-    }
+fn prefix(input_buf: &[u8]) -> [u8; 3] {
+    let buf: &[u8] = &input_buf[..3]; // perform bounds check once
+    [buf[0], buf[1], buf[2]]
 }
 
 #[inline]