Function percent_decode

test-app/runtime/src/main/cpp/ada/ada.cpp:10833–10864

}

std::string percent_decode(const std::string_view input, size_t first_percent) {
  // next line is for safety only, we expect users to avoid calling
  // percent_decode when first_percent is outside the range.
  if (first_percent == std::string_view::npos) {
    return std::string(input);
  }
  std::string dest;
  dest.reserve(input.length());
  dest.append(input.substr(0, first_percent));
  const char* pointer = input.data() + first_percent;
  const char* end = input.data() + input.size();
  // Optimization opportunity: if the following code gets
  // called often, it can be optimized quite a bit.
  while (pointer < end) {
    const char ch = pointer[0];
    size_t remaining = end - pointer - 1;
    if (ch != '%' || remaining < 2 ||
        (  // ch == '%' && // It is unnecessary to check that ch == '%'.
            (!is_ascii_hex_digit(pointer[1]) ||
             !is_ascii_hex_digit(pointer[2])))) {
      dest += ch;
      pointer++;
    } else {
      unsigned a = convert_hex_to_binary(pointer[1]);
      unsigned b = convert_hex_to_binary(pointer[2]);
      char c = static_cast<char>(a * 16 + b);
      dest += c;
      pointer += 3;
    }
  }
  return dest;
}

std::string percent_encode(const std::string_view input,
                           const uint8_t character_set[]) {