Jalali Calendar Implementation

jalali.erl

%% Copyright
-module(jalali).
-author("jrad <behradz@gmail.com>").

-define( G_DAYS_IN_MONTH, [ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ] ).
-define( J_DAYS_IN_MONTH, [ 31, 31, 31, 31, 31, 31, 30, 30, 30, 30, 30, 29 ] ).

%% API
-export([
    gregorian_to_jalali/1,
    jalali_to_gregorian/1]).

gregorian_to_jalali( {{Y,M,D}, {HH,MM,SS}} ) ->
    { gregorian_to_jalali( {Y,M,D} ), {HH,MM,SS} };
gregorian_to_jalali( {Y,M,D} ) ->
    { GY, GM, GD } = {Y - 1600, M - 1, D - 1},
    G_DAY_NO__ = 365*GY+((GY+3) div 4)-((GY+99) div 100)+((GY+399) div 400),
    G_DAY_NO_ = GD + G_DAY_NO__ + lists:sum( lists:sublist( ?G_DAYS_IN_MONTH, GM ) ),
    G_DAY_NO = add_leap( G_DAY_NO_, GM, GY ),
    J_DAY_NO = G_DAY_NO - 79,
    J_NP = J_DAY_NO div 12053,
    J_DAY_NO_ = J_DAY_NO rem 12053,
    JY = 979 + 33*J_NP + 4 * (J_DAY_NO_ div 1461),
    J_DAY_NO__ = J_DAY_NO_ rem 1461,
    {J_DAY_NO___, JY_} = extra_years( J_DAY_NO__, JY ),
    { I, J_DAY } = for_loop( 0, ?J_DAYS_IN_MONTH, J_DAY_NO___ ),
    { JY_, I+1, J_DAY+1 }.

jalali_to_gregorian( {{Y,M,D}, {HH,MM,SS}} ) ->
    { jalali_to_gregorian( {Y,M,D} ), {HH,MM,SS} };
jalali_to_gregorian( {Y,M,D} ) ->
    { JY, JM, JD } = {Y - 979, M - 1, D - 1},
    J_DAY_NO__ = 365*JY + (JY div 33)*8 + (((JY rem 33)+3) div 4),
    J_DAY_NO_ = JD + J_DAY_NO__ + lists:sum( lists:sublist( ?J_DAYS_IN_MONTH, JM ) ),
    G_DAY_NO = J_DAY_NO_ + 79,
    GY_ = 1600 + 400 * (G_DAY_NO div 146097),
    G_DAY_NO_ = G_DAY_NO rem 146097,
    {G_DAY_NO__, Leap, GYY} = add_leap_j( G_DAY_NO_ ),
    GY__ = GYY + GY_,
    GY = GY__ + (4 * (G_DAY_NO__ div 1461)),
    G_DAY_NO___ = G_DAY_NO__ rem 1461,
    {G_DAY_NO2, Leap2, GY2} = check_leap_j( G_DAY_NO___, Leap, GY ),
    { I, GDN } = for_loop_j( Leap2, 0, ?G_DAYS_IN_MONTH, G_DAY_NO2, get_leap_value(0, Leap2) ),
    {GY2, I+1, GDN+1 }.


check_leap_j( G_DAY_NO, _Leap, GY ) when G_DAY_NO >= 366 ->
    G_DAY_NO_ = G_DAY_NO-1,
    {G_DAY_NO_ rem 365, 0, GY+(G_DAY_NO_ div 365) };
check_leap_j( G_DAY_NO, Leap, GY ) ->
    {G_DAY_NO, Leap, GY }.


add_leap_j( G_DAY_NO ) when G_DAY_NO >= 36525 ->
    G_DAY_NO_ = G_DAY_NO-1,
    GY = 100 * (G_DAY_NO_ div 36524),
    G_DAY_NO__ = G_DAY_NO_ rem 36524,
    if
        G_DAY_NO__ >= 365 -> {G_DAY_NO__+1, 1, GY};
        G_DAY_NO__ < 365 -> {G_DAY_NO__, 0, GY}
    end;
add_leap_j( G_DAY_NO ) ->
    {G_DAY_NO,1,0}.


get_leap_value( I, Leap ) when (I==1) and (Leap==1) ->
    1;
get_leap_value( _I, _Leap ) ->
    0.


for_loop_j( Leap, I, [DAY_NO|Rest], G_DAY_NO, LV ) when (G_DAY_NO >= (DAY_NO+LV)) ->
    for_loop_j( Leap, I+1, Rest, G_DAY_NO - (DAY_NO+get_leap_value(I, Leap)), get_leap_value(I, Leap) );
for_loop_j( _Leap, I, _, G_DAY_NO, _LV ) ->
    {I, G_DAY_NO }.


for_loop( I, [DAY_NO|Rest], J_DAY_NO ) when (I < 11) and (J_DAY_NO >= DAY_NO) ->
    for_loop( I+1, Rest, J_DAY_NO - DAY_NO );
for_loop( I, _, J_DAY_NO ) ->
    {I, J_DAY_NO }.


add_leap( G_DAY, GM, GY ) when (GM>1) and ((GY rem 4 == 0) and (GY rem 100 /= 0) ) or (GY rem 400 == 0) ->
    G_DAY + 1;
add_leap( G_DAY, _GM, _GY ) ->
    G_DAY.


extra_years( J_DAY_NO, JY ) when J_DAY_NO >= 366 ->
    J_DAY = J_DAY_NO-1,
    { J_DAY rem 365, JY + (J_DAY div 365) };
extra_years( J_DAY_NO, JY ) when J_DAY_NO < 366 ->
    { J_DAY_NO, JY }.

jalali.js

/* jalali.js  Gregorian to Jalali and inverse date convertor
 * Copyright (C) 2001  Roozbeh Pournader <roozbeh@sharif.edu>
 * Copyright (C) 2001  Mohammad Toossi <mohammad@bamdad.org>
 * Copyright (C) 2003,2008  Behdad Esfahbod <js@behdad.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You can receive a copy of GNU Lesser General Public License at the
 * World Wide Web address <http://www.gnu.org/licenses/lgpl.html>.
 *
 * For licensing issues, contact The FarsiWeb Project Group,
 * Computing Center, Sharif University of Technology,
 * PO Box 11365-8515, Tehran, Iran, or contact us the
 * email address <FWPG@sharif.edu>.
 */

/* Changes:
 * 
 * 2008-Jul-32:
 *  Use a remainder() function to fix conversion of ancient dates
 *	(before 1600 gregorian).  Reported by Shamim Rezaei.
 *
 * 2003-Mar-29:
 *      Ported to javascript by Behdad Esfahbod
 *
 * 2001-Sep-21:
 *	Fixed a bug with "30 Esfand" dates, reported by Mahmoud Ghandi
 *
 * 2001-Sep-20:
 *	First LGPL release, with both sides of conversions
 */
 
g_days_in_month = new Array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
j_days_in_month = new Array(31, 31, 31, 31, 31, 31, 30, 30, 30, 30, 30, 29);
 
function div(a,b) {
  return Math.floor(a/b);
}

function remainder(a,b) {
  return a - div(a,b)*b;
}

function gregorian_to_jalali(g /* array containing year, month, day*/ )
{
   var gy, gm, gd;
   var jy, jm, jd;
   var g_day_no, j_day_no;
   var j_np;
 
   var i;

   gy = g[0]-1600;
   gm = g[1]-1;
   gd = g[2]-1;

   g_day_no = 365*gy+div((gy+3),4)-div((gy+99),100)+div((gy+399),400);
   
   for (i=0;i<gm;++i)
      g_day_no += g_days_in_month[i];
	  
   if (gm>1 && ((gy%4==0 && gy%100!=0) || (gy%400==0)))
      /* leap and after Feb */
      ++g_day_no;
   g_day_no += gd;
 
   j_day_no = g_day_no-79;
 
   j_np = div(j_day_no, 12053);
   j_day_no = remainder (j_day_no, 12053);

   jy = 979+33*j_np+4*div(j_day_no,1461);
   j_day_no = remainder (j_day_no, 1461);
   

   if (j_day_no >= 366) {
      jy += div((j_day_no-1),365);
      j_day_no = remainder ((j_day_no-1), 365);
   }
 
   for (i = 0; i < 11 && j_day_no >= j_days_in_month[i]; ++i) {
      j_day_no -= j_days_in_month[i];
   }
   
   jm = i+1;
   jd = j_day_no+1;

   return new Array(jy, jm, jd);
}

function jalali_to_gregorian(j /* array containing year, month, day*/ )
{
   var gy, gm, gd;
   var jy, jm, jd;
   var g_day_no, j_day_no;
   var leap;

   var i;

   jy = j[0]-979;
   jm = j[1]-1;
   jd = j[2]-1;

   j_day_no = 365*jy + div(jy,33)*8 + div((remainder (jy, 33)+3),4);
   for (i=0; i < jm; ++i)
      j_day_no += j_days_in_month[i];

   j_day_no += jd;

   g_day_no = j_day_no+79;

   gy = 1600 + 400*div(g_day_no,146097); /* 146097 = 365*400 + 400/4 - 400/100 + 400/400 */
   g_day_no = remainder (g_day_no, 146097);

   leap = 1;
   if (g_day_no >= 36525) /* 36525 = 365*100 + 100/4 */
   {
      g_day_no--;
      gy += 100*div(g_day_no,36524); /* 36524 = 365*100 + 100/4 - 100/100 */
      g_day_no = remainder (g_day_no, 36524);
      
      if (g_day_no >= 365)
         g_day_no++;
      else
         leap = 0;
   }

   gy += 4*div(g_day_no,1461); /* 1461 = 365*4 + 4/4 */
   g_day_no = remainder (g_day_no, 1461);

   if (g_day_no >= 366) {
      leap = 0;

      g_day_no--;
      gy += div(g_day_no, 365);
      g_day_no = remainder (g_day_no, 365);
   }

   for (i = 0; g_day_no >= g_days_in_month[i] + (i == 1 && leap); i++)
      g_day_no -= g_days_in_month[i] + (i == 1 && leap);
   gm = i+1;
   gd = g_day_no+1;

   return new Array(gy, gm, gd);
}

function jalali_today() {
  Today = new Date();
  j = gregorian_to_jalali(new Array(
                          Today.getFullYear(),
                          Today.getMonth()+1,
                          Today.getDate()
                          ));
  return j[2]+"/"+j[1]+"/"+j[0];
}

jalali.php

<?php
/* This file is part of:
 *    Jalali, a Gregorian to Jalali and inverse date convertor
 * Copyright (C) 2001, 2002  Roozbeh Pournader <roozbeh@farsiweb.info>
 * Copyright (C) 2001, 2002  Mohammad Toossi <mohammad@bamdad.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You can receive a copy of GNU Lesser General Public License at the
 * World Wide Web address <http://www.gnu.org/licenses/lgpl.html>.
 *
 * For licensing issues, contact The FarsiWeb Project Group,
 * Computing Center, Sharif University of Technology,
 * PO Box 11365-8515, Tehran, Iran, or contact us the
 * email address <FWPG@sharif.edu>.
 */

/* Changes:
 * 
 * 2002-Feb-19:
 *  Added PHP header and tailer
 * 2002-Jan-28:
 *	First LGPL release
 */


$g_days_in_month = array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
$j_days_in_month = array(31, 31, 31, 31, 31, 31, 30, 30, 30, 30, 30, 29);
$j_month_name = array("", "Farvardin", "Ordibehesht", "Khordad", "Tir",
                      "Mordad", "Shahrivar", "Mehr", "Aban", "Azar",
                      "Dey", "Bahman", "Esfand");

function div($a, $b)
{
   return (int) ($a / $b);
} 
  
function gregorian_to_jalali($g_y, $g_m, $g_d)
{
   global $g_days_in_month;
   global $j_days_in_month;
   
   $gy = $g_y-1600;
   $gm = $g_m-1;
   $gd = $g_d-1;

   $g_day_no = 365*$gy+div($gy+3,4)-div($gy+99,100)+div($gy+399,400);

   for ($i=0; $i < $gm; ++$i)
      $g_day_no += $g_days_in_month[$i];
   if ($gm>1 && (($gy%4==0 && $gy%100!=0) || ($gy%400==0)))
      /* leap and after Feb */
      ++$g_day_no;
   $g_day_no += $gd;
 
   $j_day_no = $g_day_no-79;
 
   $j_np = div($j_day_no, 12053);
   $j_day_no %= 12053;
 
   $jy = 979+33*$j_np+4*div($j_day_no,1461);

   $j_day_no %= 1461;
 
   if ($j_day_no >= 366) {
      $jy += div($j_day_no-1, 365);
      $j_day_no = ($j_day_no-1)%365;
   }
 
   for ($i = 0; $i < 11 && $j_day_no >= $j_days_in_month[$i]; ++$i) {
      $j_day_no -= $j_days_in_month[$i];
   }
   $jm = $i+1;
   $jd = $j_day_no+1;


   return array($jy, $jm, $jd);
}

function farsinum($str)
{
  if (strlen($str) == 1)
      $str = "0".$str;
  $out = "";
  for ($i = 0; $i < strlen($str); ++$i) {
    $c = substr($str, $i, 1); 
    $out .= pack("C*", 0xDB, 0xB0 + $c);
  }
  return $out;
}

function date_format_html($datestamp)
{
  $tzoffset = 0;
  list($date,$time) = explode(" ",$datestamp);
  list($year,$month,$day) = explode("-",$date);
  list($hour,$minute,$second) = explode(":",$time);
  $hour = $hour + $tzoffset;

  list($jyear, $jmonth, $jday) = gregorian_to_jalali($year,$month,$day);

  $sDate = farsinum($jyear - 1300)."/".farsinum($jmonth)."/".farsinum($jday)
           ."&nbsp;&nbsp;".farsinum($hour).":".farsinum($minute);
    
  return "<span lang='fa' dir='rtl'>" . $sDate . "</span>";
}

?>