void _mergeSort()

in lib/src/algorithms.dart [313:339]

• 23 lines of code
• 2 McCabe index (conditional complexity)

void _mergeSort<E, K>(
    List<E> elements,
    K Function(E element) keyOf,
    int Function(K, K) compare,
    int start,
    int end,
    List<E> target,
    int targetOffset) {
  var length = end - start;
  if (length < _mergeSortLimit) {
    _movingInsertionSort<E, K>(
        elements, keyOf, compare, start, end, target, targetOffset);
    return;
  }
  var middle = start + (length >> 1);
  var firstLength = middle - start;
  var secondLength = end - middle;
  // Here secondLength >= firstLength (differs by at most one).
  var targetMiddle = targetOffset + firstLength;
  // Sort the second half into the end of the target area.
  _mergeSort(elements, keyOf, compare, middle, end, target, targetMiddle);
  // Sort the first half into the end of the source area.
  _mergeSort(elements, keyOf, compare, start, middle, elements, middle);
  // Merge the two parts into the target area.
  _merge(keyOf, compare, elements, middle, middle + firstLength, target,
      targetMiddle, targetMiddle + secondLength, target, targetOffset);
}