Fix crash in NewFromEncodedNodeTree when passing in zero length string

CMakeLists.txt

@@ -1,7 +1,7 @@
 # CMakeList.txt : CMake project for FastNoise2
 cmake_minimum_required(VERSION 3.7.1)
 
-project(FastNoise2 VERSION 0.9.6)
+project(FastNoise2 VERSION 0.9.7)
 set(CMAKE_CXX_STANDARD 17)
 
 message("FastNoise2 Arch: ${CMAKE_SYSTEM_PROCESSOR}") 

src/FastNoise/Base64.h

@@ -99,9 +99,10 @@ namespace FastNoise
             };
 
             size_t in_len = std::strlen( input );
-            if( in_len % 4 != 0 ) return {};
-
             size_t out_len = in_len / 4 * 3;
+
+            if( out_len == 0 || in_len % 4 != 0 ) return {};
+
             if( input[in_len - 1] == '=' ) out_len--;
             if( input[in_len - 2] == '=' ) out_len--;