private LocusInfo createNextUncoveredLocusInfo(final Locus stopBeforeLocus){
  while (lastReferenceSequence <= stopBeforeLocus.getSequenceIndex() && lastReferenceSequence <= referenceSequenceMask.getMaxSequenceIndex()) {
    if (lastReferenceSequence == stopBeforeLocus.getSequenceIndex() && lastPosition + 1 >= stopBeforeLocus.getPosition()) {
      return null;
    }
    final int nextbit=referenceSequenceMask.nextPosition(lastReferenceSequence,lastPosition);
    if (nextbit == -1) {
      if (lastReferenceSequence == stopBeforeLocus.getSequenceIndex()) {
        lastPosition=stopBeforeLocus.getPosition();
        return null;
      }
      lastReferenceSequence++;
      lastPosition=0;
    }
 else     if (lastReferenceSequence < stopBeforeLocus.getSequenceIndex() || nextbit < stopBeforeLocus.getPosition()) {
      lastPosition=nextbit;
      return new LocusInfo(getReferenceSequence(lastReferenceSequence),lastPosition);
    }
 else     if (nextbit >= stopBeforeLocus.getPosition()) {
      return null;
    }
  }
  return null;
}

private LocusInfo createNextUncoveredLocusInfo ( final Locus stopBeforeLocus ) { while ( lastReferenceSequence <= stopBeforeLocus . getSequenceIndex ( ) && lastReferenceSequence <= referenceSequenceMask . getMaxSequenceIndex ( ) ) { if ( lastReferenceSequence == stopBeforeLocus . getSequenceIndex ( ) && lastPosition + 1 >= stopBeforeLocus . getPosition ( ) ) { return null ; } final int nextbit = referenceSequenceMask . nextPosition ( lastReferenceSequence , lastPosition ) ; if ( nextbit == - 1 ) { if ( lastReferenceSequence == stopBeforeLocus . getSequenceIndex ( ) ) { lastPosition = stopBeforeLocus . getPosition ( ) ; return null ; } lastReferenceSequence ++ ; lastPosition = 0 ; } else if ( lastReferenceSequence < stopBeforeLocus . getSequenceIndex ( ) || nextbit < stopBeforeLocus . getPosition ( ) ) { lastPosition = nextbit ; return new LocusInfo ( getReferenceSequence ( lastReferenceSequence ) , lastPosition ) ; } else if ( nextbit >= stopBeforeLocus . getPosition ( ) ) { return null ; } } return null ; }
create the next relevant zero - coverage locusinfo
