DateUtil.as

/*
  Copyright (c) 2008, Adobe Systems Incorporated
  All rights reserved.

  Redistribution and use in source and binary forms, with or without 
  modification, are permitted provided that the following conditions are
  met:

  * Redistributions of source code must retain the above copyright notice, 
    this list of conditions and the following disclaimer.
  
  * Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the 
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    contributors may be used to endorse or promote products derived from 
    this software without specific prior written permission.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

package com.adobe.utils
{
	import mx.formatters.DateBase;

	/**
	* 	Class that contains static utility methods for manipulating and working
	*	with Dates.
	* 
	* 	@langversion ActionScript 3.0
	*	@playerversion Flash 9.0
	*	@tiptext
	*/	
	public class DateUtil
	{
	
		/**
		*	Returns the English Short Month name (3 letters) for the Month that
		*	the Date represents.  	
		* 
		* 	@param d The Date instance whose month will be used to retrieve the
		*	short month name.
		* 
		* 	@return An English 3 Letter Month abbreviation.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*
		*	@see SHORT_MONTH
		*/	
		public static function getShortMonthName(d:Date):String
		{
			return DateBase.monthNamesShort[d.getMonth()];
		}

		/**
		*	Returns the index of the month that the short month name string
		*	represents. 	
		* 
		* 	@param m The 3 letter abbreviation representing a short month name.
		*
		*	@param Optional parameter indicating whether the search should be case
		*	sensitive
		* 
		* 	@return A int that represents that month represented by the specifed
		*	short name.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*
		*	@see SHORT_MONTH
		*/	
		public static function getShortMonthIndex(m:String):int
		{
			return DateBase.monthNamesShort.indexOf(m);
		}
		
		/**
		*	Returns the English full Month name for the Month that
		*	the Date represents.  	
		* 
		* 	@param d The Date instance whose month will be used to retrieve the
		*	full month name.
		* 
		* 	@return An English full month name.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*
		*	@see FULL_MONTH
		*/	
		public static function getFullMonthName(d:Date):String
		{
			return DateBase.monthNamesLong[d.getMonth()];	
		}

		/**
		*	Returns the index of the month that the full month name string
		*	represents. 	
		* 
		* 	@param m A full month name.
		* 
		* 	@return A int that represents that month represented by the specifed
		*	full month name.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*
		*	@see FULL_MONTH
		*/	
		public static function getFullMonthIndex(m:String):int
		{
			return DateBase.monthNamesLong.indexOf(m);
		}

		/**
		*	Returns the English Short Day name (3 letters) for the day that
		*	the Date represents.  	
		* 
		* 	@param d The Date instance whose day will be used to retrieve the
		*	short day name.
		* 
		* 	@return An English 3 Letter day abbreviation.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*
		*	@see SHORT_DAY
		*/	
		public static function getShortDayName(d:Date):String
		{
			return DateBase.dayNamesShort[d.getDay()];	
		}
		
		/**
		*	Returns the index of the day that the short day name string
		*	represents. 	
		* 
		* 	@param m A short day name.
		* 
		* 	@return A int that represents that short day represented by the specifed
		*	full month name.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*
		*	@see SHORT_DAY
		*/			
		public static function getShortDayIndex(d:String):int
		{
			return DateBase.dayNamesShort.indexOf(d);
		}

		/**
		*	Returns the English full day name for the day that
		*	the Date represents.  	
		* 
		* 	@param d The Date instance whose day will be used to retrieve the
		*	full day name.
		* 
		* 	@return An English full day name.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*
		*	@see FULL_DAY
		*/	
		public static function getFullDayName(d:Date):String
		{
			return DateBase.dayNamesLong[d.getDay()];	
		}		

		/**
		*	Returns the index of the day that the full day name string
		*	represents. 	
		* 
		* 	@param m A full day name.
		* 
		* 	@return A int that represents that full day represented by the specifed
		*	full month name.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*
		*	@see FULL_DAY
		*/		
		public static function getFullDayIndex(d:String):int
		{
			return DateBase.dayNamesLong.indexOf(d);
		}

		/**
		*	Returns a two digit representation of the year represented by the 
		*	specified date.
		* 
		* 	@param d The Date instance whose year will be used to generate a two
		*	digit string representation of the year.
		* 
		* 	@return A string that contains a 2 digit representation of the year.
		*	Single digits will be padded with 0.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/	
		public static function getShortYear(d:Date):String
		{
			var dStr:String = String(d.getFullYear());
			
			if(dStr.length < 3)
			{
				return dStr;
			}

			return (dStr.substr(dStr.length - 2));
		}

		/**
		*	Compares two dates and returns an integer depending on their relationship.
		*
		*	Returns -1 if d1 is greater than d2.
		*	Returns 1 if d2 is greater than d1.
		*	Returns 0 if both dates are equal.
		* 
		* 	@param d1 The date that will be compared to the second date.
		*	@param d2 The date that will be compared to the first date.
		* 
		* 	@return An int indicating how the two dates compare.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/	
		public static function compareDates(d1:Date, d2:Date):int
		{
			var d1ms:Number = d1.getTime();
			var d2ms:Number = d2.getTime();
			
			if(d1ms > d2ms)
			{
				return -1;
			}
			else if(d1ms < d2ms)
			{
				return 1;
			}
			else
			{
				return 0;
			}
		}

		/**
		*	Returns a short hour (0 - 12) represented by the specified date.
		*
		*	If the hour is less than 12 (0 - 11 AM) then the hour will be returned.
		*
		*	If the hour is greater than 12 (12 - 23 PM) then the hour minus 12
		*	will be returned.
		* 
		* 	@param d1 The Date from which to generate the short hour
		* 
		* 	@return An int between 0 and 13 ( 1 - 12 ) representing the short hour.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/	
		public static function getShortHour(d:Date):int
		{
			var h:int = d.hours;
			
			if(h == 0 || h == 12)
			{
				return 12;
			}
			else if(h > 12)
			{
				return h - 12;
			}
			else
			{
				return h;
			}
		}
		
		/**
		*	Returns a string indicating whether the date represents a time in the
		*	ante meridiem (AM) or post meridiem (PM).
		*
		*	If the hour is less than 12 then "AM" will be returned.
		*
		*	If the hour is greater than 12 then "PM" will be returned.
		* 
		* 	@param d1 The Date from which to generate the 12 hour clock indicator.
		* 
		* 	@return A String ("AM" or "PM") indicating which half of the day the 
		*	hour represents.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/	
		public static function getAMPM(d:Date):String
		{
			return (d.hours > 11)? "PM" : "AM";
		}

		/**
		* Parses dates that conform to RFC822 into Date objects. This method also
		* supports four-digit years (not supported in RFC822), but two-digit years
		* (referring to the 20th century) are fine, too.
		*
		* This function is useful for parsing RSS .91, .92, and 2.0 dates.
		*
		* @param str
		*
		* @returns
		*
		* @langversion ActionScript 3.0
		* @playerversion Flash 9.0
		* @tiptext
		*
		* @see http://asg.web.cmu.edu/rfc/rfc822.html
		*/		
		public static function parseRFC822(str:String):Date
		{
            var finalDate:Date;
			try
			{
				var dateParts:Array = str.split(" ");
				var day:String = null;
				
				if (dateParts[0].search(/\d/) == -1)
				{
					day = dateParts.shift().replace(/\W/, "");
				}
				
				var date:Number = Number(dateParts.shift());
				var month:Number = Number(DateUtil.getShortMonthIndex(dateParts.shift()));
				var year:Number = Number(dateParts.shift());
				var timeParts:Array = dateParts.shift().split(":");
				var hour:Number = int(timeParts.shift());
				var minute:Number = int(timeParts.shift());
				var second:Number = (timeParts.length > 0) ? int(timeParts.shift()): 0;
	
				var milliseconds:Number = Date.UTC(year, month, date, hour, minute, second, 0);
	
				var timezone:String = dateParts.shift();
				var offset:Number = 0;

				if (timezone.search(/\d/) == -1)
				{
					switch(timezone)
					{
						case "UT":
							offset = 0;
							break;
						case "UTC":
							offset = 0;
							break;
						case "GMT":
							offset = 0;
							break;
						case "EST":
							offset = (-5 * 3600000);
							break;
						case "EDT":
							offset = (-4 * 3600000);
							break;
						case "CST":
							offset = (-6 * 3600000);
							break;
						case "CDT":
							offset = (-5 * 3600000);
							break;
						case "MST":
							offset = (-7 * 3600000);
							break;
						case "MDT":
							offset = (-6 * 3600000);
							break;
						case "PST":
							offset = (-8 * 3600000);
							break;
						case "PDT":
							offset = (-7 * 3600000);
							break;
						case "Z":
							offset = 0;
							break;
						case "A":
							offset = (-1 * 3600000);
							break;
						case "M":
							offset = (-12 * 3600000);
							break;
						case "N":
							offset = (1 * 3600000);
							break;
						case "Y":
							offset = (12 * 3600000);
							break;
						default:
							offset = 0;
					}
				}
				else
				{
					var multiplier:Number = 1;
					var oHours:Number = 0;
					var oMinutes:Number = 0;
					if (timezone.length != 4)
					{
						if (timezone.charAt(0) == "-")
						{
							multiplier = -1;
						}
						timezone = timezone.substr(1, 4);
					}
					oHours = Number(timezone.substr(0, 2));
					oMinutes = Number(timezone.substr(2, 2));
					offset = (((oHours * 3600000) + (oMinutes * 60000)) * multiplier);
				}

				finalDate = new Date(milliseconds - offset);

				if (finalDate.toString() == "Invalid Date")
				{
					throw new Error("This date does not conform to RFC822.");
				}
			}
			catch (e:Error)
			{
				var eStr:String = "Unable to parse the string [" +str+ "] into a date. ";
				eStr += "The internal error was: " + e.toString();
				throw new Error(eStr);
			}
            return finalDate;
		}
	     
		/**
		* Returns a date string formatted according to RFC822.
		*
		* @param d
		*
		* @returns
		*
		* @langversion ActionScript 3.0
		* @playerversion Flash 9.0
		* @tiptext
		*
		* @see http://asg.web.cmu.edu/rfc/rfc822.html
		*/	
		public static function toRFC822(d:Date):String
		{
			var date:Number = d.getUTCDate();
			var hours:Number = d.getUTCHours();
			var minutes:Number = d.getUTCMinutes();
			var seconds:Number = d.getUTCSeconds();
			var sb:String = new String();
			sb += DateBase.dayNamesShort[d.getUTCDay()];
			sb += ", ";
			
			if (date < 10)
			{
				sb += "0";
			}
			sb += date;
			sb += " ";
			//sb += DateUtil.SHORT_MONTH[d.getUTCMonth()];
			sb += DateBase.monthNamesShort[d.getUTCMonth()];
			sb += " ";
			sb += d.getUTCFullYear();
			sb += " ";
			if (hours < 10)
			{			
				sb += "0";
			}
			sb += hours;
			sb += ":";
			if (minutes < 10)
			{			
				sb += "0";
			}
			sb += minutes;
			sb += ":";
			if (seconds < 10)
			{			
				sb += "0";
			}
			sb += seconds;
			sb += " GMT";
			return sb;
		}
	     
		/**
		* Parses dates that conform to the W3C Date-time Format into Date objects.
		*
		* This function is useful for parsing RSS 1.0 and Atom 1.0 dates.
		*
		* @param str
		*
		* @returns
		*
		* @langversion ActionScript 3.0
		* @playerversion Flash 9.0
		* @tiptext
		*
		* @see http://www.w3.org/TR/NOTE-datetime
		*/		     
		public static function parseW3CDTF(str:String):Date
		{
            var finalDate:Date;
			try
			{
				var dateStr:String = str.substring(0, str.indexOf("T"));
				var timeStr:String = str.substring(str.indexOf("T")+1, str.length);
				var dateArr:Array = dateStr.split("-");
				var year:Number = Number(dateArr.shift());
				var month:Number = Number(dateArr.shift());
				var date:Number = Number(dateArr.shift());
				
				var multiplier:Number;
				var offsetHours:Number;
				var offsetMinutes:Number;
				var offsetStr:String;
				
				if (timeStr.indexOf("Z") != -1)
				{
					multiplier = 1;
					offsetHours = 0;
					offsetMinutes = 0;
					timeStr = timeStr.replace("Z", "");
				}
				else if (timeStr.indexOf("+") != -1)
				{
					multiplier = 1;
					offsetStr = timeStr.substring(timeStr.indexOf("+")+1, timeStr.length);
					offsetHours = Number(offsetStr.substring(0, offsetStr.indexOf(":")));
					offsetMinutes = Number(offsetStr.substring(offsetStr.indexOf(":")+1, offsetStr.length));
					timeStr = timeStr.substring(0, timeStr.indexOf("+"));
				}
				else // offset is -
				{
					multiplier = -1;
					offsetStr = timeStr.substring(timeStr.indexOf("-")+1, timeStr.length);
					offsetHours = Number(offsetStr.substring(0, offsetStr.indexOf(":")));
					offsetMinutes = Number(offsetStr.substring(offsetStr.indexOf(":")+1, offsetStr.length));
					timeStr = timeStr.substring(0, timeStr.indexOf("-"));
				}
				var timeArr:Array = timeStr.split(":");
				var hour:Number = Number(timeArr.shift());
				var minutes:Number = Number(timeArr.shift());
				var secondsArr:Array = (timeArr.length > 0) ? String(timeArr.shift()).split(".") : null;
				var seconds:Number = (secondsArr != null && secondsArr.length > 0) ? Number(secondsArr.shift()) : 0;
				//var milliseconds:Number = (secondsArr != null && secondsArr.length > 0) ? Number(secondsArr.shift()) : 0;
				
				var milliseconds:Number = (secondsArr != null && secondsArr.length > 0) ? 1000*parseFloat("0." + secondsArr.shift()) : 0; 
				var utc:Number = Date.UTC(year, month-1, date, hour, minutes, seconds, milliseconds);
				var offset:Number = (((offsetHours * 3600000) + (offsetMinutes * 60000)) * multiplier);
				finalDate = new Date(utc - offset);
	
				if (finalDate.toString() == "Invalid Date")
				{
					throw new Error("This date does not conform to W3CDTF.");
				}
			}
			catch (e:Error)
			{
				var eStr:String = "Unable to parse the string [" +str+ "] into a date. ";
				eStr += "The internal error was: " + e.toString();
				throw new Error(eStr);
			}
            return finalDate;
		}
	     
		/**
		* Returns a date string formatted according to W3CDTF.
		*
		* @param d
		* @param includeMilliseconds Determines whether to include the
		* milliseconds value (if any) in the formatted string.
		*
		* @returns
		*
		* @langversion ActionScript 3.0
		* @playerversion Flash 9.0
		* @tiptext
		*
		* @see http://www.w3.org/TR/NOTE-datetime
		*/		     
		public static function toW3CDTF(d:Date,includeMilliseconds:Boolean=false):String
		{
			var date:Number = d.getUTCDate();
			var month:Number = d.getUTCMonth();
			var hours:Number = d.getUTCHours();
			var minutes:Number = d.getUTCMinutes();
			var seconds:Number = d.getUTCSeconds();
			var milliseconds:Number = d.getUTCMilliseconds();
			var sb:String = new String();
			
			sb += d.getUTCFullYear();
			sb += "-";
			
			//thanks to "dom" who sent in a fix for the line below
			if (month + 1 < 10)
			{
				sb += "0";
			}
			sb += month + 1;
			sb += "-";
			if (date < 10)
			{
				sb += "0";
			}
			sb += date;
			sb += "T";
			if (hours < 10)
			{
				sb += "0";
			}
			sb += hours;
			sb += ":";
			if (minutes < 10)
			{
				sb += "0";
			}
			sb += minutes;
			sb += ":";
			if (seconds < 10)
			{
				sb += "0";
			}
			sb += seconds;
			if (includeMilliseconds && milliseconds > 0)
			{
				sb += ".";
				sb += milliseconds;
			}
			sb += "-00:00";
			return sb;
		}
		
		/**
		 * Converts a date into just after midnight.
		 */
		public static function makeMorning(d:Date):Date
		{
			var d:Date = new Date(d.time);
			d.hours = 0;
            d.minutes = 0;
            d.seconds = 0;
            d.milliseconds = 0;
            return d;
		}
		
		/**
		 * Converts a date into just befor midnight.
		 */
		public static function makeNight(d:Date):Date
		{
			var d:Date = new Date(d.time);
			d.hours = 23;
            d.minutes = 59;
            d.seconds = 59;
            d.milliseconds = 999;				
            return d;
		}

		/**
		 * Sort of converts a date into UTC.
		 */
		public static function getUTCDate(d:Date):Date
		{
			var nd:Date = new Date();
			var offset:Number = d.getTimezoneOffset() * 60 * 1000; 
			nd.setTime(d.getTime() + offset);
			return nd;
		}
	}
}