1 // Copyright 2009 Google Inc.  All Rights Reserved.

     2 

     3 var RFC822Date = {};

     4 

     5 /**

     6  * Return a DateTime in RFC822 format.

     7  * @see http://www.w3.org/Protocols/rfc822/#z28

     8  * @param {Date} date A Date object.

     9  * @param {string} opt_tzo The timezone offset.

    10  */

    11 RFC822Date.format = function(date, opt_tzo) {

    12   var tzo = opt_tzo || RFC822Date.getTZO(date.getTimezoneOffset());

    13   var rfc822Date = RFC822Date.DAYS[date.getDay()] + ', ';

    14   rfc822Date += RFC822Date.padZero(date.getDate()) + ' ';

    15   rfc822Date += RFC822Date.MONTHS[date.getMonth()] + ' ';

    16   rfc822Date += date.getFullYear() + ' ';

    17   rfc822Date += RFC822Date.padZero(date.getHours()) + ':';

    18   rfc822Date += RFC822Date.padZero(date.getMinutes()) + ':';

    19   rfc822Date += RFC822Date.padZero(date.getSeconds()) + ' ' ;

    20   rfc822Date += tzo;

    21   return rfc822Date;

    22 };

    23 

    24 

    25 /**

    26  * @type {Array}

    27  */

    28 RFC822Date.MONTHS = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',

    29                      'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];

    30 

    31 

    32 /**

    33  * @type {Array}

    34  */

    35 RFC822Date.DAYS = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'];

    36 

    37 

    38 /**

    39  * Pads a value with a 0 if it is less than 10;

    40  * @param {number|string}

    41  * @return {string}

    42  */

    43 RFC822Date.padZero = function(val) {

    44   val = val + ''; // cast into string

    45   if (val.length < 2) {

    46     val = '0' + val;

    47   }

    48   return val;

    49 };

    50 

    51 

    52 /**

    53  * Returns a timezone offset in the format +|-dddd.

    54  * @param {String} tzo A time zone offset from GMT in minutes.

    55  * @return {string} The time zone offset as a string.

    56  */

    57 RFC822Date.getTZO = function(tzo) {

    58   var hours = Math.floor(tzo / 60);

    59   var tzoFormatted = hours > 0 ? '-' : '+';

    60 

    61   var absoluteHours = Math.abs(hours);

    62   tzoFormatted += absoluteHours < 10 ? '0' : '';

    63   tzoFormatted += absoluteHours;

    64 

    65   var moduloMinutes = Math.abs(tzo % 60);

    66   tzoFormatted += moduloMinutes == 0 ? '00' : moduloMinutes

    67 

    68   return tzoFormatted;

    69 };

    70