private static void populateDoubleWorkArrays()

in src/main/java/org/apache/datasketches/kll/KllDoublesHelper.java [439:471]
28 lines of code
11 McCabe index (conditional complexity)

  private static void populateDoubleWorkArrays( //workBuf and workLevels are modified
      final double[] workBuf, final int[] workLevels, final int provisionalNumLevels,
      final int myCurNumLevels, final int[] myCurLevelsArr, final double[] myCurDoubleItemsArr,
      final int otherNumLevels, final int[] otherLevelsArr, final double[] otherDoubleItemsArr) {

    workLevels[0] = 0;

    // Note: the level zero data from "other" was already inserted into "self".
    // This copies into workbuf.
    final int selfPopZero = KllHelper.currentLevelSizeItems(0, myCurNumLevels, myCurLevelsArr);
    System.arraycopy(myCurDoubleItemsArr, myCurLevelsArr[0], workBuf, workLevels[0], selfPopZero);
    workLevels[1] = workLevels[0] + selfPopZero;

    for (int lvl = 1; lvl < provisionalNumLevels; lvl++) {
      final int selfPop = KllHelper.currentLevelSizeItems(lvl, myCurNumLevels, myCurLevelsArr);
      final int otherPop = KllHelper.currentLevelSizeItems(lvl, otherNumLevels, otherLevelsArr);
      workLevels[lvl + 1] = workLevels[lvl] + selfPop + otherPop;
      assert selfPop >= 0 && otherPop >= 0;
      if (selfPop == 0 && otherPop == 0) { continue; }
      if (selfPop > 0 && otherPop == 0) {
        System.arraycopy(myCurDoubleItemsArr, myCurLevelsArr[lvl], workBuf, workLevels[lvl], selfPop);
      }
      else if (selfPop == 0 && otherPop > 0) {
        System.arraycopy(otherDoubleItemsArr, otherLevelsArr[lvl], workBuf, workLevels[lvl], otherPop);
      }
      else if (selfPop > 0 && otherPop > 0) {
        mergeSortedDoubleArrays( //only workBuf is modified
            myCurDoubleItemsArr, myCurLevelsArr[lvl], selfPop,
            otherDoubleItemsArr, otherLevelsArr[lvl], otherPop,
            workBuf, workLevels[lvl]);
      }
    }
  }