From 44aa44bcf1bc8eb09b400faef2b548635bbbd762 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=BC=82=E6=B5=81?= <driftluo@foxmail.com>
Date: Mon, 2 Dec 2019 22:10:10 +0800
Subject: [PATCH] reduce loops and type conversions (#176)

---
 src/crypto/aead.rs | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/crypto/aead.rs b/src/crypto/aead.rs
index 6d68efa2..19b975c2 100644
--- a/src/crypto/aead.rs
+++ b/src/crypto/aead.rs
@@ -140,10 +140,12 @@ pub fn increase_nonce(nonce: &mut [u8]) {
 /// AEAD ciphers requires to increase nonce after encrypt/decrypt every chunk
 #[cfg(not(feature = "sodium"))]
 pub fn increase_nonce(nonce: &mut [u8]) {
-    let mut prev: u16 = 1;
     for i in nonce {
-        prev += *i as u16;
-        *i = prev as u8;
-        prev >>= 8;
+        if std::u8::MAX == *i {
+            *i = 0;
+        } else {
+            *i += 1;
+            return;
+        }
     }
 }