Function parse_base16

src/ccache/util/string.cpp:255–295

}

tl::expected<Bytes, std::string>
parse_base16(std::string_view hex_string)
{
  if (hex_string.size() % 2 != 0) {
    return tl::unexpected(
      FMT("invalid hex string (odd length): \"{}\"", hex_string));
  }

  const auto from_hex_digit = [](char ch) -> std::optional<uint8_t> {
    if (ch >= '0' && ch <= '9') {
      return ch - '0';
    } else if (ch >= 'a' && ch <= 'f') {
      return ch - 'a' + 10;
    } else if (ch >= 'A' && ch <= 'F') {
      return ch - 'A' + 10;
    } else {
      return std::nullopt;
    }
  };

  Bytes result;
  result.reserve(hex_string.size() / 2);

  for (size_t i = 0; i < hex_string.size(); i += 2) {
    auto high = from_hex_digit(hex_string[i]);
    auto low = from_hex_digit(hex_string[i + 1]);

    if (!high) {
      return tl::unexpected(
        FMT("invalid hex character at position {}: \"{}\"", i, hex_string));
    }
    if (!low) {
      return tl::unexpected(
        FMT("invalid hex character at position {}: \"{}\"", i + 1, hex_string));
    }

    result.push_back(static_cast<uint8_t>((*high << 4) | *low));
  }

  return result;
}

tl::expected<double, std::string>
parse_double(const std::string& value)