/***********************************************************************
 *  J a v a G P S - GPS access library and Java API                    *
 *  Copyright (C) 2001 Ulrich Walther                                  *
 *                                                                     *
 *  This program is free software; you can redistribute it and/or      *
 *  modify it under the terms of the GNU General Public License as     *
 *  published by the Free Software Foundation; either version 2 of     *
 *  the License, or (at your option) any later version.                *
 *                                                                     *
 *  This program is distributed in the hope that it will be useful,    *
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of     *
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU   *
 *  General Public License for more details.                           *
 *                                                                     *
 *  You should have received a copy of the GNU General Public          *
 *  License along with this program; if not, write to the Free         *
 *  Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,     *
 *  MA 02111-1307 USA                                                  *
 ***********************************************************************/

package org.iu.gps;

/**
 *  Takes a NMEA-0183 message to tokenize.
 *
 *@author    walther
 */
class NMEATokenizer {
	private String msg;


	NMEATokenizer( String _msg )
	{
		msg = _msg;
	}


	boolean hasMoreTokens()
	{
		return getPos() >= 0;
	}


	// return next token (filters delimiter)
	String nextToken()
	{
		String t = msg.substring( 0, getPos() );
		msg = msg.substring( getPos() + 1 );
		return t;
	}


	// return position of next delimiter (, or *), -1 means no more delimiters
	// available
	private int getPos()
	{
		int p1 = msg.indexOf( "," );
		int p2 = msg.indexOf( "*" );

		if ( p1 == -1 && p2 == -1 )
		{
			return -1;
		}

		if ( p1 == -1 )
		{
			p1 = msg.length() - 1;
		}
		if ( p2 == -1 )
		{
			p2 = msg.length() - 1;
		}

		return Math.min( p1, p2 );
	}
}