Method toMessageSet

app/src/main/java/com/sun/mail/imap/Utility.java:55–105

Run thru the given array of messages, apply the given Condition on each message and generate sets of contiguous sequence-numbers for the successful messages. If a message in the given array is found to be expunged, it is ignored. ASSERT: Since this method uses and returns message sequence numbers,

(Message[] msgs, Condition cond)

     * @return		the MessageSet array
     */
    public static MessageSet[] toMessageSet(Message[] msgs, Condition cond) {
	List<MessageSet> v = new ArrayList<>(1);
	int current, next;

	IMAPMessage msg;
	for (int i = 0; i < msgs.length; i++) {
	    msg = (IMAPMessage)msgs[i];
	    if (msg.isExpunged()) // expunged message, skip it
		continue;

	    current = msg.getSequenceNumber();
	    // Apply the condition. If it fails, skip it.
	    if ((cond != null) && !cond.test(msg))
		continue;
	    
	    MessageSet set = new MessageSet();
	    set.start = current;

	    // Look for contiguous sequence numbers
	    for (++i; i < msgs.length; i++) {
		// get next message
		msg = (IMAPMessage)msgs[i];

		if (msg.isExpunged()) // expunged message, skip it
		    continue;
		next = msg.getSequenceNumber();

		// Does this message match our condition ?
		if ((cond != null) && !cond.test(msg))
		    continue;
		
		if (next == current+1)
		    current = next;
		else { // break in sequence
		    // We need to reexamine this message at the top of
		    // the outer loop, so decrement 'i' to cancel the
		    // outer loop's autoincrement 
		    i--;
		    break;
		}
	    }
	    set.end = current;
	    v.add(set);
	}
	
	if (v.isEmpty()) // No valid messages
	    return null;
	else {
	    return v.toArray(new MessageSet[v.size()]);
	}
    }
    /**
     * Sort (a copy of) the given array of messages and then
     * run thru the sorted array of messages, apply the given