@Override
protected void writePostingNotDocid(Posting _p) throws IOException
{
super.writePostingNotDocid(_p);
final BlockPosting p = (BlockPosting)_p;
final int positions[] = p.getPositions();
final int l = positions.length;
//System.err.println("posting has " + l + "blocks");
output.writeUnary(l+1);
if (l == 0)
return;