dateparser.java

已经移植好的java虚拟机

		int y;
		long millis = 0;
		
		boolean isLeap = year%4 == 0;
		y = year - 1;
		long julianDay = 365L*y + floorDivide(y, 4) + (JAN_1_1_JULIAN_DAY - 3);
		
		isLeap = isLeap && ((year%100 != 0) || (year%400 == 0));
		// Add 2 because Gregorian calendar starts 2 days after Julian calendar
		julianDay += floorDivide(y, 400) - floorDivide(y, 100) + 2;
		julianDay += isLeap ? LEAP_NUM_DAYS[month] : NUM_DAYS[month];
		julianDay += day;

		return julianDay;
	}

	/**
	 * Divide two long integers, returning the floor of the quotient.
	 * <p>
	 * Unlike the built-in division, this is mathematically well-behaved.
	 * E.g., <code>-1/4</code> => 0
	 * but <code>floorDivide(-1,4)</code> => -1.
	 * @param numerator the numerator
	 * @param denominator a divisor which must be > 0
	 * @return the floor of the quotient.
	 */
	private static final long floorDivide(long numerator, long denominator) {
		// We do this computation in order to handle
		// a numerator of Long.MIN_VALUE correctly
		return (numerator >= 0) ?
			numerator / denominator :
			((numerator + 1) / denominator) - 1;
	}

	// public String toString() {
	// 	return "" + month + "/" + day + "/" + year 
	// 		+ " " + hour + ":" + minute + ":" + second;
	// }

	private long julianDayToMillis(long julian) {
		return (julian - julianDayOffset) * millisPerDay;
	}

	private void internalParse(String s) {
		int year = -1;
		int mon = -1;
		int mday = -1;
		int hour = -1;
		int min = -1;
		int sec = -1;
		int millis = -1;
		int c = -1;
		int i = 0;
		int n = -1;
		int wst = -1;
		int tzoffset = -1;
		int prevc = 0;
	syntax: {
		if (s == null)
		break syntax;
		int limit = s.length();
		while (i < limit) {
		c = s.charAt(i);
		i++;
		if (c <= ' ' || c == ',')
			continue;
		if (c == '(') {	// skip comments
			int depth = 1;
			while (i < limit) {
			c = s.charAt(i);
			i++;
			if (c == '(') depth++;
			else if (c == ')')
				if (--depth <= 0)
					break;
			}
			continue;
		}
		if ('0' <= c && c <= '9') {
			n = c - '0';
			while (i < limit && '0' <= (c = s.charAt(i)) && c <= '9') {
			n = n * 10 + c - '0';
			i++;
			}
			if (prevc == '+' || prevc == '-' && year>=0) {
			// timezone offset
			if (n < 24)
				n = n * 60;	// EG. "GMT-3"
			else
				n = n % 100 + n / 100 * 60;	// eg "GMT-0430"
			if (prevc == '+')	// plus means east of GMT
				n = -n;
			if (tzoffset != 0 && tzoffset != -1)
				break syntax;
			tzoffset = n;
			} else if (n >= 70)
			if (year >= 0)
				break syntax;
			else if (c <= ' ' || c == ',' || c == '/' || i >= limit)
				// year = n < 1900 ? n : n - 1900;
				year = n < 100 ? n + 1900 : n;
			else
				break syntax;
			else if (c == ':')
			if (hour < 0)
				hour = (byte) n;
			else if (min < 0)
				min = (byte) n;
			else
				break syntax;
			else if (c == '/')
			if (mon < 0)
				mon = (byte) (n - 1);
			else if (mday < 0)
				mday = (byte) n;
			else
				break syntax;
			else if (i < limit && c != ',' && c > ' ' && c != '-')
			break syntax;
			else if (hour >= 0 && min < 0)
			min = (byte) n;
			else if (min >= 0 && sec < 0)
			sec = (byte) n;
			else if (mday < 0)
			mday = (byte) n;
			else
			break syntax;
			prevc = 0;
		} else if (c == '/' || c == ':' || c == '+' || c == '-')
			prevc = c;
		else {
			int st = i - 1;
			while (i < limit) {
			c = s.charAt(i);
			if (!('A' <= c && c <= 'Z' || 'a' <= c && c <= 'z'))
				break;
			i++;
			}
			if (i <= st + 1)
			break syntax;
			int k;
			for (k = wtb.length; --k >= 0;)
			if (wtb[k].regionMatches(true, 0, s, st, i - st)) {
				int action = ttb[k];
				if (action != 0) {
				if (action == 1) {	// pm
					if (hour > 12 || hour < 1)
					break syntax;
					else if (hour < 12)
										hour += 12;
								} else if (action == 14) {  // am
					if (hour > 12 || hour < 1)
					break syntax;
					else if (hour == 12)
										hour = 0;
								} else if (action <= 13) {	// month!
					if (mon < 0)
					mon = (byte) (action - 2);
					else
					break syntax;
								} else {
					tzoffset = action - 10000;
								}
							}
				break;
			}
			if (k < 0)
			break syntax;
			prevc = 0;
		}
		}
		if (year < 1583 || mon < 0 || mday < 0)
		break syntax;
		if (sec < 0)
		sec = 0;
		if (min < 0)
		min = 0;
		if (hour < 0)
		hour = 0;

		this.year = year;
		month = mon;
		day = mday;
		this.hour = hour;
        this.tzoffset = -tzoffset * 60 * 1000;
		minute = min;
		second = sec;
		milli = 0;
		return;
	}
		// syntax error
		throw new IllegalArgumentException();
	}

	private static Hashtable timezones;

	private int[] days_in_month = {31, 28, 31, 30, 31, 30, 31,
									31, 30, 31, 30, 31};
	private String[] month_shorts = {"Jan", "Feb", "Mar", "Apr", 
		"May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
	private String[] weekday_shorts = {"Mon", "Tue", "Wed", "Thu",
										"Fri", "Sat", "Sun"};

	private static long julianDayOffset = 2440588;
	private static int millisPerHour = 60 * 60 * 1000;
	private static int millisPerDay = 24 * millisPerHour;
	private static final int JAN_1_1_JULIAN_DAY = 1721426; // January 1, year 1 (Gregorian)

	private final static String wtb[] = {
		"am", "pm",
		"monday", "tuesday", "wednesday", "thursday", "friday",
		"saturday", "sunday",
		"january", "february", "march", "april", "may", "june",
		"july", "august", "september", "october", "november", "december",
		"gmt", "ut", "utc", "est", "edt", "cst", "cdt",
		"mst", "mdt", "pst", "pdt"
		// this time zone table needs to be expanded
	};

	private final static int ttb[] = {
		14, 1, 0, 0, 0, 0, 0, 0, 0,
		2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
		10000 + 0, 10000 + 0, 10000 + 0,	// GMT/UT/UTC
		10000 + 5 * 60, 10000 + 4 * 60,	// EST/EDT
		10000 + 6 * 60, 10000 + 5 * 60,
		10000 + 7 * 60, 10000 + 6 * 60,
		10000 + 8 * 60, 10000 + 7 * 60
	};

	private static final int NUM_DAYS[]
		= {0,31,59,90,120,151,181,212,243,273,304,334}; 
	private static final int LEAP_NUM_DAYS[]
		= {0,31,60,91,121,152,182,213,244,274,305,335}; 

	static {
		timezones = new Hashtable();
		timezones.put("GMT", new Integer(0 * millisPerHour));
		timezones.put("UT", new Integer(0 * millisPerHour));
		timezones.put("UTC", new Integer(0 * millisPerHour));
		timezones.put("PST", new Integer(-8 * millisPerHour));
		timezones.put("PDT", new Integer(-7 * millisPerHour));
		timezones.put("JST", new Integer(9 * millisPerHour));

		local_tz = ((Integer)timezones.get("PST")).intValue();
	}
}