leftBlock = concatLines(leftComparator, diff.leftStart(), diff.leftLength());
rightBlock = concatLines(rightComparator, diff.rightStart(), diff.rightLength());
}
if (leftBlock == null) {
for (int i = 0; i < diff.leftLength(); i++) {
int currentLine = diff.leftStart() + i;
output.startLine(DiffLineType.REMOVED);
output.addUnchangedText(leftComparator.getLine(currentLine));
output.endLine();
}