Method ExtractFlag

Source/cmGlobalXCodeGenerator.cxx:2281–2307

This function removes each occurrence of the flag and returns the last one (i.e., the dominant flag in GCC)

// This function removes each occurrence of the flag and returns the last one
// (i.e., the dominant flag in GCC)
std::string cmGlobalXCodeGenerator::ExtractFlag(char const* flag,
                                                std::string& flags)
{
  std::string retFlag;
  std::string::size_type lastOccurrencePos = flags.rfind(flag);
  bool saved = false;
  while (lastOccurrencePos != std::string::npos) {
    // increment pos, we use lastOccurrencePos to reduce search space on next
    // inc
    std::string::size_type pos = lastOccurrencePos;
    if (pos == 0 || flags[pos - 1] == ' ') {
      while (pos < flags.size() && flags[pos] != ' ') {
        if (!saved) {
          retFlag += flags[pos];
        }
        flags[pos] = ' ';
        pos++;
      }
      saved = true;
    }
    // decrement lastOccurrencePos while making sure we don't loop around
    // and become a very large positive number since size_type is unsigned
    lastOccurrencePos = lastOccurrencePos == 0 ? 0 : lastOccurrencePos - 1;
    lastOccurrencePos = flags.rfind(flag, lastOccurrencePos);
  }
  return retFlag;
}

// This function removes each matching occurrence of the expression and
// returns the last one (i.e., the dominant flag in GCC)