public function getEditString()

in src/utils/PhutilEditDistanceMatrix.php [230:329]
77 lines of code
20 McCabe index (conditional complexity)

  public function getEditString() {
    $this->requireSequences();

    $x = $this->x;
    $y = $this->y;

    if (!$x && !$y) {
      return $this->padEditString('');
    }

    if (!$x) {
      return $this->padEditString(str_repeat('i', count($y)));
    }

    if (!$y) {
      return $this->padEditString(str_repeat('d', count($x)));
    }

    if ($x === $y) {
      return $this->padEditString(str_repeat('s', count($x)));
    }

    $max = $this->getMaximumLength();
    if (count($x) > $max || count($y) > $max) {
      $this->reachedMaximumLength = true;
      return $this->padEditString(
        str_repeat('d', count($x)).
        str_repeat('i', count($y)));
    }

    $matrix = $this->getTypeMatrix();

    $xx = count($x);
    $yy = count($y);

    $transposes = array();
    $str = '';
    while (true) {
      $type = $matrix[$xx][$yy];

      if (is_array($type)) {
        $chr = 't';
        $transposes[$type[0]][$type[1]] = true;
        $type = $type[2];
      } else {
        $chr = $type;
      }

      if (isset($transposes[$xx][$yy])) {
        $chr = 't';
      }

      if ($type == 's' || $type == 'x') {
        $xx -= 1;
        $yy -= 1;
      } else if ($type == 'i') {
        $yy -= 1;
      } else if ($type == 'd') {
        $xx -= 1;
      } else {
        throw new Exception(pht("Unknown type '%s' in type matrix.", $type));
      }

      $str .= $chr;

      if ($xx <= 0 && $yy <= 0) {
        break;
      }
    }

    $str = strrev($str);

    // For full smoothing, we pad the edit string before smoothing it, so
    // ranges of similar characters at the beginning or end of the string can
    // also be smoothed.

    // For internal smoothing, we only smooth ranges within the change itself.

    $smoothing = $this->getApplySmoothing();
    switch ($smoothing) {
      case self::SMOOTHING_FULL:
        $str = $this->padEditString($str);
        $str = $this->applySmoothing($str, true);
        break;
      case self::SMOOTHING_INTERNAL:
        $str = $this->applySmoothing($str, false);
        $str = $this->padEditString($str);
        break;
      case self::SMOOTHING_NONE:
        $str = $this->padEditString($str);
        break;
      default:
        throw new Exception(
          pht(
            'Unknown smoothing type "%s".',
            $smoothing));
    }

    return $str;
  }