Function getPathRelativeToLocation

core/filetools.cpp:365–422

---------------------------------------------------------------------------

//---------------------------------------------------------------------------
  std::string getPathRelativeToLocation(const std::string &_pathToAlter, const std::string &_fixedPath)
  {
//Make copies so we can change them for processing
    std::string pathToAlter = _pathToAlter;
    std::string fixedPath = _fixedPath;

//if a relative path cannot be written
    if ( (rootName(pathToAlter)).compare(rootName(fixedPath)) != 0 )
      return pathToAlter;
//if the two paths are the same
    if ( pathToAlter.compare(fixedPath) == 0)
      return std::string(".");

//if the path ends with a "\" then cut it off
    if (pathToAlter.find_last_of(dirsep) == pathToAlter.length() - 1)
      pathToAlter = pathToAlter.substr(0, pathToAlter.length() - 1);
    if (fixedPath.find_last_of(dirsep) == fixedPath.length() - 1)
      fixedPath = fixedPath.substr(0, fixedPath.length() - 1);


    std::string relativePath;
//If the entire fixed path is contained within the path to be given
    if ( pathToAlter.length() >= fixedPath.length()
         && pathToAlter.substr(0, fixedPath.length()).compare(fixedPath) == 0 )
    {
      //Tben we just need "./" and to append the remainder (non-matched part) of pathToAlter
      relativePath = std::string(".") + dirsep + pathToAlter.substr(fixedPath.length() + 1, pathToAlter.length() - fixedPath.length());
    }
//Otherwise we need at least one "../" step in the relative path
    else
    {
      relativePath = std::string("..") + dirsep;
      //step up a level in the fixed path and see if it is now contained within the pathToAlter
      std::string choppedFixed = upOneLevel(fixedPath);
      //As long as the "choppedFixed" is not contained in pathToAlter
      while ( pathToAlter.substr(0, choppedFixed.length()).compare(choppedFixed) != 0)
      {
        //Keep stepping up one level and appending "../" to relative path
        relativePath = relativePath + std::string("..") + dirsep;
        choppedFixed = upOneLevel(choppedFixed);
      }

      //if choppedFixed ends with a "\" then cut it off (e.g. if it is C:\ then '\' always appended)
      if (choppedFixed.find_last_of(dirsep) == choppedFixed.length() - 1)
        choppedFixed = choppedFixed.substr(0, choppedFixed.length() - 1);

      //A string to hold the path that we need to append to the "../../../" we made
      std::string endOfRelPath = std::string("");

      //Take the end part of "pathToAlter" (The part which doesn't match with choppedFixed)
      if (pathToAlter.length() > choppedFixed.length())
        endOfRelPath = pathToAlter.substr(choppedFixed.length() + 1, pathToAlter.length() - choppedFixed.length()) ;

      //Append this to the "../../../" part
      relativePath = relativePath + endOfRelPath;
    }
    return relativePath;
  }