positionForIndex method

int positionForIndex(dynamic index)

Implementation

int positionForIndex(index) {
  // For an empty vector the tuple can be inserted at the beginning
  if (elements.isEmpty) {
    return 0;
  }

  var start = 0,
      end = elements.length ~/ 2,
      sliceLength = end - start,
      pivotPoint = (sliceLength ~/ 2).floor(), //Math.floor(sliceLength / 2),
      pivotIndex = elements[pivotPoint * 2];

  while (sliceLength > 1) {
    if (pivotIndex < index) {
      start = pivotPoint;
    }

    if (pivotIndex > index) {
      end = pivotPoint;
    }

    if (pivotIndex == index) {
      break;
    }

    sliceLength = end - start;
    pivotPoint =
        start + (sliceLength ~/ 2).floor(); //Math.floor(sliceLength / 2);
    pivotIndex = elements[pivotPoint * 2];
  }

  if (pivotIndex == index) {
    return pivotPoint * 2;
  }

  if (pivotIndex > index) {
    return pivotPoint * 2;
  }

  if (pivotIndex < index) {
    return (pivotPoint + 1) * 2;
  }
  return 0;
}