Don't call findBase64CharIndex on invalid chars

source/utils/CarlaBase64Utils.hpp

@@ -101,12 +101,12 @@ std::vector<uint8_t> carla_getChunkFromBase64String(const char* const base64stri
 
     if (i != 0)
     {
+        for (j=0; j<i && j<4; ++j)
+            charArray4[j] = CarlaBase64Helpers::findBase64CharIndex(static_cast<char>(charArray4[j]));
+
         for (j=i; j<4; ++j)
             charArray4[j] = 0;
 
-        for (j=0; j<4; ++j)
-            charArray4[j] = CarlaBase64Helpers::findBase64CharIndex(static_cast<char>(charArray4[j]));
-
         charArray3[0] =  (charArray4[0] << 2)        + ((charArray4[1] & 0x30) >> 4);
         charArray3[1] = ((charArray4[1] & 0xf) << 4) + ((charArray4[2] & 0x3c) >> 2);
         charArray3[2] = ((charArray4[2] & 0x3) << 6) +   charArray4[3];