patch.diff

From 33ac99c83160760eb42bc3481d0f47ef3f2adcc8 Mon Sep 17 00:00:00 2001
From: archshift <gh@archshift.com>
Date: Tue, 24 Mar 2015 19:01:48 -0700
Subject: [PATCH] Small optimization in add_ctr

---
 source/decryptor/crypto.c | 19 ++++---------------
 1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/source/decryptor/crypto.c b/source/decryptor/crypto.c
index 60accc4..acddd02 100644
--- a/source/decryptor/crypto.c
+++ b/source/decryptor/crypto.c
@@ -92,26 +92,15 @@ void add_ctr(void* ctr, u32 carry)
     u32 counter[4];
     u8 *outctr = (u8 *) ctr;
     u32 sum;
-    int32_t i;
+    u32 i;
 
     for(i=0; i<4; i++) {
         counter[i] = (outctr[i*4+0]<<24) | (outctr[i*4+1]<<16) | (outctr[i*4+2]<<8) | (outctr[i*4+3]<<0);
-    }
 
-    for(i=3; i>=0; i--)
-    {
-        sum = counter[i] + carry;
-        if (sum < counter[i]) {
-            carry = 1;
-        }
-        else {
-            carry = 0;
-        }
-        counter[i] = sum;
-    }
+        sum = counter[3-i] + carry;
+        carry = (u32)(sum < counter[3-i]);
+        counter[3-i] = sum;
 
-    for(i=0; i<4; i++)
-    {
         outctr[i*4+0] = counter[i]>>24;
         outctr[i*4+1] = counter[i]>>16;
         outctr[i*4+2] = counter[i]>>8;
-- 
2.2.1