static String HHVM_FUNCTION(bcadd, const String& left, const String& right,
                            int64_t scale /* = -1 */) {
  scale = adjust_scale(scale);
  bc_num first, second, result;
  bc_init_num(&first);
  bc_init_num(&second);
  bc_init_num(&result);
  php_str2num(&first, (char*)left.data());
  php_str2num(&second, (char*)right.data());
  bc_add(first, second, &result, scale);
  if (result->n_scale > scale) {
    result->n_scale = scale;
  }
  String ret(bc_num2str(result), AttachString);
  bc_free_num(&first);
  bc_free_num(&second);
  bc_free_num(&result);
  return ret;
}
static String HHVM_FUNCTION(bcadd, const String& left, const String& right,
                            int64_t scale  ) {
  scale = adjust_scale(scale);
  bc_num first, second, result;
  bc_init_num(&first);
  bc_init_num(&second);
  bc_init_num(&result);
  php_str2num(&first, (char*)left.data());
  php_str2num(&second, (char*)right.data());
  bc_add(first, second, &result, scale);
  if (result->n_scale > scale) {
    result->n_scale = scale;
  }
  String ret(bc_num2str(result), AttachString);
  bc_free_num(&first);
  bc_free_num(&second);
  bc_free_num(&result);
  return ret;
}