Function GenerateRegExForNumber

Modules/DICOM/src/mitkDICOMTagPath.cpp:23–51

namespace
{
  std::string GenerateRegExForNumber(unsigned int tagNumber)
  {
    std::ostringstream resultRegEx;

    std::ostringstream hexNumber;
    hexNumber << std::hex << tagNumber; // default std::hex output is lowercase
    std::regex reg_character("([a-f]+)"); // so only check for lowercase characters here
    if (std::regex_search(hexNumber.str(), reg_character))
    {
      // hexNumber contains a-f characters; emit both cases via a
      // non-capturing alternation. Plain "(...|...)" would silently
      // introduce an extra capture group that the persistence name /
      // key templates do not count when they assign $N placeholders,
      // causing the templates' selection slots to receive the element
      // id instead of the numeric index they were meant to capture.
      resultRegEx << "(?:"
        << std::setw(4) << std::setfill('0') << std::hex << tagNumber
        << "|"
        << std::setw(4) << std::setfill('0') << std::hex << std::uppercase << tagNumber << std::nouppercase
        << ")";
    }
    else
    {
      // only decimal values (0-9) contained in hexNumber - no need to modify the result
      resultRegEx << std::setw(4) << std::setfill('0') << std::hex << tagNumber;
    }

    return resultRegEx.str();
  }
}

namespace mitk