/**
 * ParseParameter contains number parsers for applet initialization.<p>
 *
 * Copyright &copy; 1996-1998 Martin Minow. All Rights Reserved.<p>
 * World map copyright &copy; 1992-97 Apple Computer Inc. All Rights Reserved.
 * Used by permission.<p>
 * Moon Image from Michael Myers
 *
 * Permission to use, copy, modify, and redistribute this software and its
 * documentation for personal, non-commercial use is hereby granted provided that
 * this copyright notice and appropriate documentation appears in all copies. This
 * software may not be distributed for fee or as part of commercial, "shareware,"
 * and/or not-for-profit endevors including, but not limited to, CD-ROM collections,
 * online databases, and subscription services without specific license.<p>
 *
 * @author <a href="mailto:minow@merrymeet.com">Martin Minow</a>
 * @author <a href="http://www.netavs.com:80/~mhmyers/moon.html">Michael Myers (moon image)</a>
 * @version 1.1
 * 1996.09.15
 * Set tabs every 4 characters.
 */

// package Classes;

import java.util.*;
import java.applet.*;
import java.awt.*;
import java.awt.image.*;
import java.net.*;

public class ParseParameter
{
	String			paramString;
	int				index			= 0;
	
	/**
	 * Initialize a parameter parse.
	 * @param applet		Where to fetch the parameter from.
	 * @param paramName	The name of the parameter to fetch.
	 * @throws NumberFormatException if the parameter is missing.
	 */
	public ParseParameter(
			Applet			applet,
			String			paramName
		) throws NumberFormatException
	{
		this(applet.getParameter(paramName));
	}
	/**
	 * Initialize a parameter parse.
	 * @param paramString	The parameter string.
	 * @throws NumberFormatException if the parameter is null.
	 */
	public ParseParameter(
			String			paramString
		) throws NumberFormatException
	{
		if (paramString == null) {
			throw new NumberFormatException("no parameter");
		}
		this.paramString	= paramString;
	}
	/**
	 * Parse an integer value.
	 * @return the parsed (or default) value.
	 * @throws NumberFormatException if the parameter is misformatted.
	 */
	public int parseInt()
		throws NumberFormatException
	{
		return (Integer.valueOf(paramString).intValue());
	}
	/**
	 * Parse a floating-point latitude or longitude value.
	 * @param	tagString		"NS" or "EW" (the first is positive, the second negative).
	 *							The function call paraemter must be given in upper case.
	 *							The tag in the actual parameter may be given in either case. 
	 * @param	defaultValue	A value to return in case of missing data or parse errors..
	 * @return the parsed (or default) value.
	 * The format is:<pre>
	 *		[N S]
	 *		[+ -] degrees.fraction
	 *		[+ -] degrees:minutes
	 *		[N S]
	 * </pre>
	 * Only one [N S] may be specified.
	 */
	public double parseLatLong(
			String		tagString
		)	throws NumberFormatException
	{
		char	tag		= 0;
		char c = Character.toUpperCase(paramString.charAt(index));
		if (c == tagString.charAt(0) || c == tagString.charAt(1)) {
			tag = c;
			index++;
		}
		double result	= number();
		if (index < paramString.length()) {
			if (tag == 0) {
				c		= Character.toUpperCase(paramString.charAt(index));
				if (c == tagString.charAt(0) || c == tagString.charAt(1)) {
					tag = c;
					index++;
				}
			}
		}
		if (index != paramString.length()) {
			throw new NumberFormatException(paramString);
		}
		if (tag == tagString.charAt(1)) {
			result = (-result);
		}
		return (result);
	}
	/**
	 * Parse a number.
	 */
	private double number()
	{
		double sign			= sign();
		double result		= integer();
		result				+= fraction();
		result				*= sign;
		return (result);
	}
	/**
	 * Parse the +/- sign.
	 */
	private double sign()
	{
		double sign = 1.0;
		// System.out.println(paramName + " (sign) at " + index + ", \"" + paramString.substring(index) + "\"");
		if (index < paramString.length()) {
			if (paramString.charAt(index) == '-') {
				sign = -1.0;
				index++;
			}
			else if (paramString.charAt(index) == '+') {
				index++;
			}
		}
		return (sign);
	}
	/**
	 * Parse the fraction part.
	 */
	private double fraction()
	{
		double fraction = 0.0;
		if (index < paramString.length()) {
			char c				= paramString.charAt(index);
			// System.out.println(paramName + " (fraction) at " + index + ", \"" + paramString.substring(index) + "\"");
			if (c == '.') {
				double power = 1.0;
				index++;
				for (; index < paramString.length(); index++) {
					c = paramString.charAt(index);
					if (c >= '0' && c <= '9') {
						fraction = (fraction * 10.0) + ((double) (c - '0'));
						power *= 10.0;
					}
					else {
						break;
					}
				}
				fraction /= power;
			}
			else if (c == ':') {	/* "fraction" is in 1/60's units */
				index++;
				fraction = integer() / 60.0;
			}
		}
		return (fraction);
	}
	/**
	 * Parse an integer.
	 */
	private double integer()
	{
		double result		= 0.0;
		// System.out.println(paramName + " (integer) at " + index + ", \"" + paramString.substring(index) + "\"");
		while (index < paramString.length()) {
			char c			= paramString.charAt(index);
			if (c >= '0' && c <= '9') {
				result = (result * 10.0) + ((double) (c - '0'));
				index++;
			}
			else {
				break;
			}
		}
		return (result);
	}
}