Fix BinaryToHex()

Previously the function stopped short on nul bytes ("\0") due to usage
of the SArg() macro, which does not retrieve the length of the lua
string.

before the fix: `BinaryToHex("a\0b")` -> `"61"`
after the fix: `BinaryToHex("a\0b")` -> `"610062"`

src/RageUtil.cpp

@@ -225,11 +225,11 @@ bool IsHexVal( const RString &s )
 	return true;
 }
 
-RString BinaryToHex( const void *pData_, int iNumBytes )
+RString BinaryToHex( const void *pData_, size_t iNumBytes )
 {
 	const unsigned char *pData = (const unsigned char *) pData_;
 	RString s;
-	for( int i=0; i<iNumBytes; i++ )
+	for( size_t i=0; i<iNumBytes; i++ )
 	{
 		unsigned val = pData[i];
 		s += ssprintf( "%02x", val );
@@ -2481,7 +2481,19 @@ LuaFunction( URLEncode, URLEncode( SArg(1) ) );
 LuaFunction( PrettyPercent, PrettyPercent( FArg(1), FArg(2) ) );
 //LuaFunction( IsHexVal, IsHexVal( SArg(1) ) );
 LuaFunction( lerp, lerp(FArg(1), FArg(2), FArg(3)) );
-LuaFunction( BinaryToHex, BinaryToHex( SArg(1) ) );
+
+int LuaFunc_BinaryToHex(lua_State* L);
+int LuaFunc_BinaryToHex(lua_State* L)
+{
+	size_t l;
+	const char *s = luaL_checklstring(L, 1, &l);
+
+	RString hex = BinaryToHex(s, l);
+
+	LuaHelpers::Push(L, hex);
+	return 1;
+}
+LUAFUNC_REGISTER_COMMON(BinaryToHex);
 
 int LuaFunc_commify(lua_State* L);
 int LuaFunc_commify(lua_State* L)

src/RageUtil.h

@@ -352,7 +352,7 @@ float fmodfp( float x, float y );
 int power_of_two( int input );
 bool IsAnInt( const RString &s );
 bool IsHexVal( const RString &s );
-RString BinaryToHex( const void *pData_, int iNumBytes );
+RString BinaryToHex( const void *pData_, size_t iNumBytes );
 RString BinaryToHex( const RString &sString );
 bool HexToBinary( const RString &s, unsigned char *stringOut );
 bool HexToBinary( const RString &s, RString *sOut );