diff method

List<CellUpdate> diff(Buffer other)

Compute a list of CellUpdates needed to turn this buffer into other.

Implementation

List<CellUpdate> diff(Buffer other) {
  final result = <CellUpdate>[];
  final len =
      content.length < other.content.length ? content.length : other.content.length;
  var i = 0;
  while (i < len) {
    final current = other.content[i];
    final previous = content[i];
    switch (current.diffOption) {
      case CellDiffOption.skip:
        i++;
        continue;
      case CellDiffOption.forcedWidth:
        final width = charWidthOf(current.symbol);
        if (current != previous) {
          final pos = posOf(i);
          result.add(CellUpdate(pos.x, pos.y, current));
        }
        i += width;
        continue;
      case CellDiffOption.none:
      case CellDiffOption.alwaysUpdate:
        final cellWidth = charWidthOf(current.symbol);
        final needsUpdate = current.diffOption == CellDiffOption.alwaysUpdate || current != previous;
        if (needsUpdate) {
          final pos = posOf(i);
          result.add(CellUpdate(pos.x, pos.y, current));
        }
        i += cellWidth > 1 ? cellWidth : 1;
    }
  }
  return result;
}