Calendar Functions

    Table of Contents

    • cal_days_in_month — Return the number of days in a month for a given year and calendar
    • cal_from_jd — Converts from Julian Day Count to a supported calendar
    • cal_info — Returns information about a particular calendar
    • cal_to_jd — Converts from a supported calendar to Julian Day Count
    • easter_date — Get Unix timestamp for midnight on Easter of a given year
    • easter_days — Get number of days after March 21 on which Easter falls for a given year
    • frenchtojd — Converts a date from the French Republican Calendar to a Julian Day Count
    • gregoriantojd — Converts a Gregorian date to Julian Day Count
    • jddayofweek — Returns the day of the week
    • jdmonthname — Returns a month name
    • jdtofrench — Converts a Julian Day Count to the French Republican Calendar
    • jdtogregorian — Converts Julian Day Count to Gregorian date
    • jdtojewish — Converts a Julian day count to a Jewish calendar date
    • jdtojulian — Converts a Julian Day Count to a Julian Calendar Date
    • jdtounix — Convert Julian Day to Unix timestamp
    • jewishtojd — Converts a date in the Jewish Calendar to Julian Day Count
    • juliantojd — Converts a Julian Calendar date to Julian Day Count
    • unixtojd — Convert Unix timestamp to Julian Day

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    User Contributed Notes 8 notes

    up
    20
    david dot scourfield at llynfi dot co dot uk
    17 years ago
    I created this function a while ago and needed it again recently, so had to trawl through some old files to find it. Thought I'd post it here in case anyone else finds it useful.

    <?php

    /*
    * Function to calculate which days are British bank holidays (England & Wales) for a given year.
    *
    * Created by David Scourfield, 07 August 2006, and released into the public domain.
    * Anybody may use and/or modify this code.
    *
    * USAGE:
    *
    * array calculateBankHolidays(int $yr)
    *
    * ARGUMENTS
    *
    * $yr = 4 digit numeric representation of the year (eg 1997).
    *
    * RETURN VALUE
    *
    * Returns an array of strings where each string is a date of a bank holiday in the format "yyyy-mm-dd".
    *
    * See example below
    *
    */

    function calculateBankHolidays($yr) {

    $bankHols = Array();

    // New year's:
    switch ( date("w", strtotime("$yr-01-01 12:00:00")) ) {
    case     6:
    $bankHols[] = "$yr-01-03";
    break;
    case     0:
    $bankHols[] = "$yr-01-02";
    break;
    default:
    $bankHols[] = "$yr-01-01";
    }

    // Good friday:
    $bankHols[] = date("Y-m-d", strtotime( "+".(easter_days($yr) - 2)." days", strtotime("$yr-03-21 12:00:00") ));

    // Easter Monday:
    $bankHols[] = date("Y-m-d", strtotime( "+".(easter_days($yr) + 1)." days", strtotime("$yr-03-21 12:00:00") ));

    // May Day:
    if ($yr == 1995) {
    $bankHols[] = "1995-05-08"; // VE day 50th anniversary year exception
    } else {
    switch (    date("w", strtotime("$yr-05-01 12:00:00"))) {
    case     0:
    $bankHols[] = "$yr-05-02";
    break;
    case     1:
    $bankHols[] = "$yr-05-01";
    break;
    case     2:
    $bankHols[] = "$yr-05-07";
    break;
    case     3:
    $bankHols[] = "$yr-05-06";
    break;
    case     4:
    $bankHols[] = "$yr-05-05";
    break;
    case     5:
    $bankHols[] = "$yr-05-04";
    break;
    case     6:
    $bankHols[] = "$yr-05-03";
    break;
    }
    }

    // Whitsun:
    if ($yr == 2002) { // exception year
    $bankHols[] = "2002-06-03";
    $bankHols[] = "2002-06-04";
    } else {
    switch (    date("w", strtotime("$yr-05-31 12:00:00"))) {
    case     0:
    $bankHols[] = "$yr-05-25";
    break;
    case     1:
    $bankHols[] = "$yr-05-31";
    break;
    case     2:
    $bankHols[] = "$yr-05-30";
    break;
    case     3:
    $bankHols[] = "$yr-05-29";
    break;
    case     4:
    $bankHols[] = "$yr-05-28";
    break;
    case     5:
    $bankHols[] = "$yr-05-27";
    break;
    case     6:
    $bankHols[] = "$yr-05-26";
    break;
    }
    }

    // Summer Bank Holiday:
    switch (date("w", strtotime("$yr-08-31 12:00:00"))) {
    case     0:
    $bankHols[] = "$yr-08-25";
    break;
    case     1:
    $bankHols[] = "$yr-08-31";
    break;
    case     2:
    $bankHols[] = "$yr-08-30";
    break;
    case     3:
    $bankHols[] = "$yr-08-29";
    break;
    case     4:
    $bankHols[] = "$yr-08-28";
    break;
    case     5:
    $bankHols[] = "$yr-08-27";
    break;
    case     6:
    $bankHols[] = "$yr-08-26";
    break;
    }

    // Christmas:
    switch ( date("w", strtotime("$yr-12-25 12:00:00")) ) {
    case     5:
    $bankHols[] = "$yr-12-25";
    $bankHols[] = "$yr-12-28";
    break;
    case     6:
    $bankHols[] = "$yr-12-27";
    $bankHols[] = "$yr-12-28";
    break;
    case     0:
    $bankHols[] = "$yr-12-26";
    $bankHols[] = "$yr-12-27";
    break;
    default:
    $bankHols[] = "$yr-12-25";
    $bankHols[] = "$yr-12-26";
    }

    // Millenium eve
    if ($yr == 1999) {
    $bankHols[] = "1999-12-31";
    }

    return     $bankHols;

    }

    /*
    * EXAMPLE:
    *
    */

    header("Content-type: text/plain");

    $bankHolsThisYear = calculateBankHolidays(2007);

    print_r($bankHolsThisYear);

    ?>

    Will output this result:

    Array
    (
    [0] => 2007-01-01
    [1] => 2007-04-06
    [2] => 2007-04-09
    [3] => 2007-05-07
    [4] => 2007-05-28
    [5] => 2007-08-27
    [6] => 2007-12-25
    [7] => 2007-12-26
    )
    up
    6
    obaida dot habboush at gmail dot com
    7 years ago
    Hello ,

    there is a mistake with function name

    at class HijriCalendar {
    .
    .
    .
    .
    .
    .
    function HijriToGregorian($m, $d, $y)
    {
    //// jd_to_cal -> It Should Be -> cal_to_jd
    return jd_to_cal(CAL_GREGORIAN, HijriCalendar::HijriToJD($m, $d, $y));
    }
    }
    up
    1
    jthome at fcgov dot com
    21 years ago
    Had a similar problem as curlee, except I needed to create a JDE_ERP date. [format is CYYDDD]

    <?php

    function jde_date_create($month, $day, $year){
    /*
    * NOTE: $month and $day CANNOT have leading zeroes,
    * $year must be'YYYY' format
    */
    $jde_year_prefix = substr($year, 0, 1) - 1;
    $jde_year_suffix = substr($year, -2);

    //note that valid years for mktime are 1902-2037
    $timestamp = mktime(0,0,0,$month, $day, $year);
    $baseline_timestamp = mktime(0,0,0,1,0,$year);

    $day_count = round(($timestamp - $baseline_timestamp)/86400);
    $day_count_padded = str_pad($day_count,3,"0",STR_PAD_LEFT);

    return (    $jde_year_prefix . $jde_year_suffix . $day_count_padded);

    }

    echo     jde_date_create(6,25,2000);// will return '103176'

    ?>

    --
    Jim
    up
    0
    simon at chronolabs dot org dot au
    17 years ago
    This is the egyptian calendar which was the first 365 day calendar on the planet it has no leap year which makes it a little inaccurate but you can work on your own implementation of this code when you like, this is another implementation of the roun floating point code which is a universal code for generating date codec's you can make practically all calendars with this code the $pweight is based on my research on carbon date stamping etc of when egypt epoch or PPO was made, some people argue a few thousand years while other can date egypts epoch being around 30000 years ago!! This is on the basis of tidal marking on statues and momuments when the are was covered in water after construction from sea level rising.

    <?php

    print_r    (EgyptCalendar(time(),0));

    function     EgyptianCalendar($unix_time, $gmt,
    $poffset = '1970-02-26 7:45 PM',
    $pweight = '-9777600.22222222223',
    $defiency='nonedeficient',
    $timeset= array("hours" => 24,
    "minutes" => 60,
    "seconds" => 60))
    {
    // Code Segment 1 – Calculate Floating Point
    $tme = $unix_time;

    if (    $gmt>0){$gmt=-$gmt;} else {$gmt=abs($gmt);}

    $ptime = strtotime($poffset)+(60*60*gmt);
    $weight = $pweight+(1*gmt);

    $egypt_xa = ($tme)/(24*60*60);
    $egypt_ya = $ptime/(24*60*60);
    $egypt = (($egypt_xa -$egypt_ya) -
    $weight)+(microtime/999999);

    // Code Segment 2 – Set month day arrays
    $nonedeficient = array(
    "seq1" => array(30,30,30,30,30,30,30,30,30,30,30,30,5));

    $monthnames = array(
    "seq1" => array('Thoth','Phaophi','Athyr','Choiak',
    'Tybi', 'Mecheir','Phamenoth','Pharmuthi','Pachon',
    'Payni','Epiphi','Mesore','epagomenai'));

    $monthusage = isset($defiency) ? ${$defiency} : $deficient;

    // Code Segment 3 – Calculate month number, day number
    foreach($monthusage as $key => $item){
    $i++;
    foreach(    $item as $numdays){
    $ttl_num=$ttl_num+$numdays;
    $ttl_num_months++;
    }
    }

    $revolutionsperyear = $ttl_num / $i;
    $numyears = egyptd((floor($egypt) / $revolutionsperyear),0);
    $avg_num_month = $ttl_num_months/$i;
    $jtl = abs(abs($egypt) -
    ceil($revolutionsperyear*($numyears+1)));

    while(    $month==0){
    $day=0;
    $u=0;
    foreach(    $monthusage as $key => $item){
    $t=0;
    foreach(    $item as $numdays){
    $t++;
    $tt=0;
    for(    $sh=1;$sh<=$numdays;$sh++){
    $ii=$ii+1;
    $tt++;
    if (    $ii==floor($jtl)){
    if (    $egypt>0){
    $daynum = $tt;
    $month = $t;
    } else {
    $daynum = $numdays-$tt;
    $month = $avg_num_month-$t;
    }
    $sequence = $key;
    $nodaycount=true;
    }
    }
    if (    $nodaycount==false)
    $day++;
    }
    $u++;
    }
    }

    //$numyears = abs($numyears);

    $timer = substr($egypt, strpos($egypt,'.')+1,
    strlen($egypt)-strpos($egypt,'.')-1);
    $egypt_out= $numyears.'/'.$month.'/'.$daynum.' '.$day.'.'.
    floor(intval(substr($timer,0,2))/100*$timeset['hours']).':'.
    floor(intval(substr($timer,2,2))/100*$timeset['minutes']).':'.
    floor(intval(substr($timer,4,2))/100*$timeset['seconds']).'.'.
    substr($timer,6,strlen($timer)-6);
    $egypt_obj = array('year'=>$numyears,
    'month'=>$month,
    'mname' => $monthnames[$sequence][$month-1],
    'day'=>$daynum,
    'jtl'=>$jtl,
    'day_count'=>$day,
    'hours'=>floor(intval(substr($timer,0,2))/100
    *$timeset['hours']),
    'minute'=>floor(intval(substr($timer,2,2))/100
    *$timeset['minutes']),
    'seconds'=>floor(intval(substr($timer,4,2))/100
    *$timeset['seconds']),
    'microtime'=>substr($timer,6,strlen($timer)-6),
    'strout'=>$egypt_out);

    return     $egypt_obj;
    }

    ?>

    btw in my previous post of the Mayan Tikal calendar the top part of the function was chopped off in my code cut and paste that is the line for the function which looks like, the top 3 line will need to be replace with:

    <?php

    print_r    (MayanTikalCalendar(time(),0));

    function     MayanTikalCalendar($unix_time, $gmt,

    ?>
    up
    -5
    amichauer at gmx dot de
    19 years ago
    <?php

    class HijriCalendar
    {
    function     monthName($i) // $i = 1..12
    {
    static     $month = array(
    "M?x?rr?m", "Safar", "Rabig-?l-?ww?l", "Rabig-?l-Ax?r",
    "C?m?d-?l-?ww?l", "C?m?d-?l-Ax?r", "Rac?b", "???b?n",
    "Ramazan", "??w?l", "Z?-?l-Q??d?", "Z?-?l-Xicc?"
    );
    return     $month[$i-1];
    }

    function     GregorianToHijri($time = null)
    {
    if (    $time === null) $time = time();
    $m = date('m', $time);
    $d = date('d', $time);
    $y = date('Y', $time);

    return     HijriCalendar::JDToHijri(
    cal_to_jd(CAL_GREGORIAN, $m, $d, $y));
    }

    function     HijriToGregorian($m, $d, $y)
    {
    return     jd_to_cal(CAL_GREGORIAN,
    HijriCalendar::HijriToJD($m, $d, $y));
    }

    # Julian Day Count To Hijri
    function JDToHijri($jd)
    {
    $jd = $jd - 1948440 + 10632;
    $n = (int)(($jd - 1) / 10631);
    $jd = $jd - 10631 * $n + 354;
    $j = ((int)((10985 - $jd) / 5316)) *
    ((int)(    50 * $jd / 17719)) +
    ((int)(    $jd / 5670)) *
    ((int)(    43 * $jd / 15238));
    $jd = $jd - ((int)((30 - $j) / 15)) *
    ((int)((    17719 * $j) / 50)) -
    ((int)(    $j / 16)) *
    ((int)((    15238 * $j) / 43)) + 29;
    $m = (int)(24 * $jd / 709);
    $d = $jd - (int)(709 * $m / 24);
    $y = 30*$n + $j - 30;

    return array(    $m, $d, $y);
    }

    # Hijri To Julian Day Count
    function HijriToJD($m, $d, $y)
    {
    return (int)((    11 * $y + 3) / 30) +
    354 * $y + 30 * $m -
    (int)((    $m - 1) / 2) + $d + 1948440 - 385;
    }
    };

    $hijri = HijriCalendar::GregorianToHijri( time() );
    echo     $hijri[1].'. '.HijriCalendar::monthName($hijri[0]).' '.$hijri[2];

    ?>
    up
    -2
    simon at chronolabs dot org dot au
    16 years ago
    <?php

    // You need to replace this section in Function EgyptianCalendar
    // As well as Function MayanTihkalCalendar
    $revolutionsperyear = $ttl_num / $i;
    $numyears = floor((ceil($roun) / $revolutionsperyear));
    $avg_num_month = $ttl_num_months/$i;
    $jtl = abs(abs($roun) - ceil($revolutionsperyear*($numyears+1)));
    while(    $month==0){
    $day=0;
    $u=0;
    foreach(    $monthusage as $key => $item){
    $t=0;
    foreach(    $item as $numdays){
    $t++;
    $tt=0;
    for(    $sh=1;$sh<=$numdays;$sh++){
    $ii=$ii+1;
    $tt++;
    if (    $ii==floor($jtl)){
    if (    $roun<0){
    $daynum = $tt;
    $month = $t;
    } else {
    $daynum = $numdays-($tt-1);
    $month = $avg_num_month-($t-1);
    }
    $sequence = $key;
    $nodaycount=true;
    }
    }
    if (    $nodaycount==false)
    $day++;
    }
    $u++;
    }
    }
    ?>

    This section of code need to be changed in the calculation I noticed today in our RounCalendar we had a zero day this function will calculate the month and day correctly for the calendars, it is a pretty universe piece of code, I am sorry it wasn't properly tested and need some refactoring.
    up
    -2
    simon at chronolabs dot org dot au
    17 years ago
    This will return the mayan long count calendar which cycle reaches 13.0.0.0.0 in 2012, I have had to compress the changemaya function for this code library so if you want to space it out your more than welcome. It works with unix time. To call the routine use the following syntax. The mayan calendar is a day count that is around 5000 years old, it tracks our cestial position in the galaxy

    <?php

    echo MayanLongCount(time());

    function     MayanLongCount($tme){

    $config = array('ppo' => array(13,0,0,0,0),
    'epoch' => strtotime('2012-12-21'));

    $diff=(($tme-$config['epoch'])/(60*60*24));
    $ppo = changemaya($config['ppo'],ceil($diff));

    return     $ppo[0].'.'.$ppo[1].'.'.$ppo[2].'.'.$ppo[3].'.'.$ppo[4];
    }

    function     changemaya($ppo,$diff){
    if (    $diff>0) { $amount=1; } else { $amount=-1; }
    for (    $sh=1;$sh<abs($diff);$sh++){ if ($ppo[4]+$amount>20){
    if (    $ppo[3]+$amount>20){ if ($ppo[2]+$amount>20){
    if (    $ppo[1]+$amount>20){ if ($ppo[0]+$amount>20){
    $ppo[0]=0; $ppo[1]=0; $ppo[2]=0; $ppo[3]=0; $ppo[4]=0;
    } else {     $ppo[1]=0; $ppo[0]=$ppo[0]+$amount;}
    } else {     $ppo[2]=0; $ppo[1]=$ppo[1]+$amount; }
    } else {    $ppo[3]=0; $ppo[2]=$ppo[2]+$amount; }
    } else {     $ppo[4]=0; $ppo[3]=$ppo[3]+$amount; }
    } elseif (    $ppo[4]+$amount<0){ if ($ppo[3]+$amount<0){
    if (    $ppo[2]+$amount<0){ if ($ppo[1]+$amount<0){
    if (    $ppo[0]+$amount<0){ $ppo[0]=20; $ppo[1]=0;
    $ppo[2]=0; $ppo[3]=0; $ppo[4]=0;
    } else {     $ppo[1]=20; $ppo[0]=$ppo[0]+$amount; }
    } else {     $ppo[2]=20; $ppo[1]=$ppo[1]+$amount; }
    } else {     $ppo[3]=20; $ppo[2]=$ppo[2]+$amount; }
    } else {     $ppo[4]=20; $ppo[3]=$ppo[3]+$amount; }
    } else {     $ppo[4]=$ppo[4]+$amount;}}
    return     $ppo;
    }

    ?>

    Thanks!!
    up
    -2
    curlee at mindspring dot com
    21 years ago
    I solved a problem with Julian dates that are used in the JD Edwards ERP package (running on AS/400). The Julian format for this system is as follows: CYYDDD

    Where C is 0 for 1900 and 1 for 2000
    DDD is the day of the year count

    I used the mktime built-in php function to convert dates to the normal DD/MM/YYYY format. This function will convert dates that are between 1970 and 2038 (limitation of unix timestamps and the mktime function)

    The $jde_date var needs to be a 6 len STRING.... if you use a numeric var type it will drop the leading 0 for any date that represents 1900.... this will botch the substr functions and thus make the whole thing wrong.

    <?php
    function jde_date_conv($jde_date)
    {

    $ct = substr($jde_date,0,1);
    $yr = substr($jde_date,1,2);
    $dy = substr($jde_date,3,3);

    if(    $ct == 0) $yr_pfx = 19;
    if(    $ct == 1) $yr_pfx = 20;

    $tlt_yr = $yr_pfx.$yr;

    $base_time = mktime(0,0,0,1,0,$tlt_yr);

    $unix_time = ($dy * 86400) + $base_time;

    return     date("m/d/Y" , $unix_time);
    }
    ?>
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