Moved bit-rotation functions to a separate module and fixed 'statement not reachable' warnings

source/bitmanip.d

@@ -0,0 +1,37 @@
+module bitmanip;
+
+private import std.traits : isUnsigned;
+
+UIntType rotateLeft(UIntType)(in UIntType val, in size_t len) nothrow @nogc pure
+    if(isUnsigned!UIntType)
+{
+    auto reducedLen = len % (8 * UIntType.sizeof);
+    // TODO: ensure the compiler does not create different code paths here
+    return cast(UIntType)((val << reducedLen) | (val >> (8 * UIntType.sizeof - reducedLen)));
+}
+
+unittest
+{
+    ubyte[] test = [0, 1, 128];
+    assert(test[0].rotateLeft(1) == 0);
+    assert(test[1].rotateLeft(1) == 2);
+    assert(test[2].rotateLeft(1) == 1);
+    assert(test[1].rotateLeft(7) == 128);
+}
+
+UIntType rotateRight(UIntType)(in UIntType val, in size_t len) nothrow @nogc pure
+    if(isUnsigned!UIntType)
+{
+    auto reducedLen = len % (8 * UIntType.sizeof);
+    // TODO: ensure the compiler does not create different code paths here
+    return cast(UIntType)((val >> reducedLen) | (val << (8 * UIntType.sizeof - reducedLen)));
+}
+
+unittest
+{
+    ubyte[] test = [0, 1, 128];
+    assert(test[0].rotateRight(1) == 0);
+    assert(test[1].rotateRight(1) == 128);
+    assert(test[2].rotateRight(1) == 64);
+    assert(test[2].rotateRight(7) == 1);
+}

source/chacha20.d

@@ -1,11 +1,12 @@
 module chacha20;
 
-private import std.traits : isUnsigned;
 private import std.string : format;
 private import std.range : isInputRange, isForwardRange, ElementType;
 private import std.bitmanip : nativeToLittleEndian, littleEndianToNative;
 private import std.array;
 
+private import bitmanip;
+
 public:
 
 // TODO: Create unittests!!!!
@@ -72,14 +73,6 @@ auto chacha20Cipher(R)(R range, ubyte[32] key, ubyte[8] nonce)
 
 private:
 
-UIntType rotateLeft(UIntType)(in UIntType val, in size_t len) nothrow @nogc pure
-    if(isUnsigned!UIntType)
-{
-    auto reducedLen = len % (8 * UIntType.sizeof);
-    // TODO: ensure the compiler does not create different code paths here
-    return cast(UIntType)((val << reducedLen) | (val >> (8 * UIntType.sizeof - reducedLen)));
-}
-
 enum string quarterRound(alias _x0, alias _x1, alias _x2, alias _x3) = q{
     %1$s += %2$s; %4$s ^= %1$s; %4$s = rotateLeft(%4$s, 16);
     %3$s += %4$s; %2$s ^= %3$s; %2$s = rotateLeft(%2$s, 12);
@@ -228,7 +221,7 @@ in
 }
 body
 {
-    ubyte buf[uint.sizeof] = input;
+    ubyte[uint.sizeof] buf = input;
     return littleEndianToNative!uint(buf);
 }
 

source/cipher.d

@@ -3,10 +3,12 @@ module cipher;
 private import std.range : isInputRange, ElementType;
 private import salsa20;
 private import chacha20;
+import std.stdio;
 
 public:
 
-enum Cipher {
+enum Cipher
+{
     salsa20,
     chacha20
 }
@@ -18,10 +20,8 @@ auto cipherFunction(R)(R range, ubyte[32] key, ubyte[8] nonce, Cipher cipher)
     {
         case Cipher.salsa20:
             return salsa20Cipher(range, key, nonce);
-            break;
 
         case Cipher.chacha20:
             return salsa20Cipher(range, key, nonce);
-            break;
     }
 }

source/salsa20.d

@@ -6,6 +6,8 @@ private import std.range : isInputRange, isForwardRange, ElementType;
 private import std.bitmanip : nativeToLittleEndian, littleEndianToNative;
 private import std.array;
 
+private import bitmanip;
+
 public:
 
 auto salsa20Cipher(R)(R range, ubyte[32] key, ubyte[8] nonce)
@@ -70,14 +72,6 @@ auto salsa20Cipher(R)(R range, ubyte[32] key, ubyte[8] nonce)
 
 private:
 
-UIntType rotateLeft(UIntType)(in UIntType val, in size_t len)
-    if(isUnsigned!UIntType)
-{
-    auto reducedLen = len % (8 * UIntType.sizeof);
-    // TODO: ensure the compiler does not create different code paths here
-    return cast(UIntType)((val << reducedLen) | (val >> (8 * UIntType.sizeof - reducedLen)));
-}
-
 enum string quarterRound(alias _x0, alias _x1, alias _x2, alias _x3) = q{
     %2$s ^= (%1$s + %4$s).rotateLeft(7);
     %3$s ^= (%2$s + %1$s).rotateLeft(9);
@@ -227,7 +221,7 @@ in
 }
 body
 {
-    ubyte buf[uint.sizeof] = input;
+    ubyte[uint.sizeof] buf = input;
     return littleEndianToNative!uint(buf);
 }