Function decodeBase64

cpp/QuickBase64Impl.cpp:30–44

Mirrors V8's Uint8Array.fromBase64 (TC39-aligned): - last_chunk_handling_options::loose accepts inputs without '=' padding - decode_up_to_bad_char mirrors V8's ArrayBufferFromBase64 - base64_default_or_url accepts both standard (+/) and URL-safe (-_) alphabets

// - decode_up_to_bad_char mirrors V8's ArrayBufferFromBase64
// - base64_default_or_url accepts both standard (+/) and URL-safe (-_) alphabets
std::string decodeBase64(const std::string& input) {
  size_t max_len = simdutf::maximal_binary_length_from_base64(input.data(), input.size());
  std::string result(max_len, '\0');
  size_t out_len = max_len;
  auto r = simdutf::base64_to_binary_safe(
      input.data(), input.size(), result.data(), out_len,
      simdutf::base64_default_or_url,
      simdutf::last_chunk_handling_options::loose,
      /*decode_up_to_bad_char*/ true);
  if (r.error != simdutf::error_code::SUCCESS) {
    throw std::runtime_error("Input is not valid base64-encoded data");
  }
  result.resize(out_len);
  return result;
}

} // namespace