Thai date utility

<?php
//=======================================================================
// Description: Date & Time utility class
// Author:  Sirichai Meemutha (jjoi@gayji.net)
// Ver:     $Id: class.DateUtil.php v1.02
//
// License: This code is released under GPL
// Copyright (C) 2005 JF Systems
//========================================================================

class DateUtil {
    public $ts;

    public static $arrMonthName = array(1 => 'มกราคม','กุมภาพันธ์','มีนาคม','เมษายน','พฤษภาคม','มิถุนายน','กรกฎาคม','สิงหาคม','กันยายน','ตุลาคม','พฤศจิกายน','ธันวาคม');
    public static $arrShortMonthName = array(1 => 'ม.ค.','ก.พ.','มี.ค.','เม.ย.','พ.ค.','มิ.ย.','ก.ค.','ส.ค.','ก.ย.','ต.ค.','พ.ย.','ธ.ค.');
    public static $arrDoW = array('อาทิตย์','จันทร์','อังคาร','พุธ','พฤหัสบดี','ศุกร์','เสาร์');
    public static $arrShortDoW = array('อา','จ','อ','พ','พฤ','ศ','ส');

    public static $arrMonthNameEN = array(1 => 'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December');
    public static $arrShortMonthNameEN = array(1 => 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec');
    public static $arrDoWEN = array('Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday');
    public static $arrShortDoWEN = array('Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat');


    public function __construct($ts = NULL) {
        if (is_null($ts))
            $ts = time();

        $this -> ts = $ts;
    }

    public function duration($ts) {
        $distance = $this->ts - $ts;
        list($Y, $n, $j) = self::dateParts('Ynj', $ts);
        $days = intval(($this->ts - $ts) / self::SECS_PER_DAY);

        // new timestamp, substract yer
        $years = intval($days / 365);
        $ts = mktime(0, 0, 0, $n, $j, $Y + $years);
        list($Y, $n, $j) = self::dateParts('Ynj', $ts);
        $days = intval(($this->ts - $ts) / self::SECS_PER_DAY);

        $months = intval($days / 30);
        $ts = mktime(0, 0, 0, $n + $months, $j, $Y);
        list($Y, $n, $j) = self::dateParts('Ynj', $ts);
        $days = intval(($this->ts - $ts) / self::SECS_PER_DAY);

        return array(
            'year'=>$years,
            'month'=>$months,
            'day'=>$days,
        );
    }

    public function GetFDOM($ts = NULL) {
        if (!is_numeric($ts))
            $ts = $this -> ts;

        list($cal_n, $cal_Y) = self::DateParts('nY', $ts);
        return mktime(0, 0, 0, $cal_n, 1, $cal_Y);
    }

    public  function GetLDOM($ts = NULL) {
        if (!is_numeric($ts))
            $ts = $this -> ts;

        list($cal_n, $cal_Y) = self::DateParts('nY', $ts);
        return mktime(0, 0, 0, $cal_n + 1, 0, $cal_Y);
    }

    public function GetMaxJ($ts = NULL) {
        return intval(date('j', $this -> GetLDOM($ts)));
    }

    /**
     * หาค่า timestamp ของวันปัจจุบัน ณ เที่ยงคืน
     *
     * @return int
     */
    public function Today() {
        list($j, $n, $Y) = self::DateParts('jnY', time());
        return (mktime(0, 0, 0, $n, $j, $Y));
    }

    // static functions
    public static function th_date($format,$t=NULL)
    {
        if (!is_numeric($t))
            return NULL;

        $output = '';

        $arrFormat = explode("\r\n",chunk_split($format,1));
        foreach ($arrFormat as $key => $val)
        {
            if(preg_match('/[aABdgGhHiIjLmnOrsStTUwWzZ]/',$val))
            {
                $output .= date($val,$t);
            }
            else
            {
                switch($val)
                {
                    case 'D':       // Day of Week, short name
                        $output .= self::$arrShortDoW[date('w',$t)];
                        break;
                    case 'F':       // Month, full name
                        $output .= self::$arrMonthName[date('n',$t)];
                        break;
                    case 'l':           // Day of Week , long name
                        $output .= self::$arrDoW[date('w',$t)];
                        break;
                    case 'M':       // Month, short name
                        $output .= self::$arrShortMonthName[date('n',$t)];
                        break;
                    case 'Y':       // 4 digit Year
                        $output .= date('Y',$t) + self::AD2BE;
                        break;
                    case 'y':       // 2 digit Year
                        $output .= (date('y',$t) + 43) % 100;
                        break;
                    default:
                            $output .= $val;
                }
            }
        }
        return $output;
    }

    // usage ex: list($Y,$m,$j) = DateUtil::DateParts("Ymj",$time_var);
    public static function dateParts($dateFormat,$t = NULL)
    {
//      if (!$t) $t = time();
        $arr_keys = preg_split('//', $dateFormat, -1, PREG_SPLIT_NO_EMPTY);
        while(list($key,$val) = each($arr_keys))
        {
            $value = is_null($t)?NULL:date($val,$t);
            $arr_output[$val] = $value;
            $arr_output[$key] = $value;
        }
        return $arr_output;
    }

    /**
     * แปลงค่า date/time string ให้เป็น timestamp
     *
     * @param string $str
     * @param int $BEYear
     * @return int
     */
    public static function Parse($str, $BEYear = true) {
        preg_match('/(\d{1,2})\/(\d{1,2})\/(\d{2,4})\s*(\d{1,2})?\:?(\d{1,2})?\:?(\d{1,2})?/', $str, $matches);
        $yearOffset = $BEYear?DateUtil::AD2BE:0;
        if (DateUtil::DATEFORMAT == 'jnY') {
            $dIndex = 1;
            $mIndex = 2;
            $yIndex = 3;
        }
        else {
            $dIndex = 2;
            $mIndex = 1;
            $yIndex = 3;
        }

        if (count($matches) == 4) {
            return mktime(0, 0, 0, $matches[$mIndex], $matches[$dIndex], $matches[$yIndex] - $yearOffset);
        }
        else if(count($matches) >= 6) {
            $hh = $matches[4];
            $mm = $matches[5];
            $ss = $matches[6]?$matches[6]:0;
            return mktime($hh, $mm, $ss, $matches[$mIndex], $matches[$dIndex], $matches[$yIndex] - $yearOffset);
        }
        else
            return NULL;
    }

    /**
     * Parse date string ใน ISO 8601 format
     * @param string $str ค่าของ date string
     * @return int
     */
    public static function ParseSQLDate($str) {
        if(is_null($str))
            return NULL;
        $dt = @strtotime($str);

        if ($dt === -1 || $dt === false)
            return NULL;
        else
            return $dt;
    }

    /**
     * get Day ในแต่ละ Week
     * @reture  boolean
     */
    public static function getSunToMonDay(){
        if((date(self::NUMERIC_FORMAT_DAY) == self::SUN_NUMERIC) || (date(self::NUMERIC_FORMAT_DAY) == self::MON_NUMERIC))
            return true;
        else
            return false;

    }
    /**
     * get Day ในแต่ละ Week
     * @reture  boolean
     */
    public static function getFriToTue(){
        if((date(self::NUMERIC_FORMAT_DAY) == self::FRI_NUMERIC) || (date(self::NUMERIC_FORMAT_DAY) == self::SAT_NUMERIC) || (date(self::NUMERIC_FORMAT_DAY) == self::SUN_NUMERIC) || (date(self::NUMERIC_FORMAT_DAY) == self::MON_NUMERIC) || (date(self::NUMERIC_FORMAT_DAY) == self::TUE_NUMERIC))
            return true;
        else
            return false;

    }

    /**
     * get Day ในแต่ละ Week
     * @reture  boolean
     */
    public static function getFriToSun(){
        if((date(self::NUMERIC_FORMAT_DAY) == self::FRI_NUMERIC) || (date(self::NUMERIC_FORMAT_DAY) == self::SAT_NUMERIC) || (date(self::NUMERIC_FORMAT_DAY) == self::SUN_NUMERIC))
            return true;
        else
            return false;

    }

    /**
    * get Day ในแต่ละ Week
    * @reture  boolean
    */
    public static function getFriToSAT(){
        if((date(self::NUMERIC_FORMAT_DAY) == self::FRI_NUMERIC) || (date(self::NUMERIC_FORMAT_DAY) == self::SAT_NUMERIC))
            return true;
        else
            return false;

    }

    /**
     * get Day ในแต่ละ Week
     * @reture  boolean
     */
    public static function getWedToThu(){
        if((date(self::NUMERIC_FORMAT_DAY) == self::WED_NUMERIC) || (date(self::NUMERIC_FORMAT_DAY) == self::THU_NUMERIC))
            return true;
        else
            return false;

    }

    public static function getTime(){
        if(strtotime(date('H:i:s',time())) >= strtotime('00:00:00') && strtotime(date('H:i:s',time())) <= strtotime('12:00:00') ){
            return self::HALF_DAY_BREAKFAST;
        }
        return self::HALF_DAY_AFTERNOON;
    }
    // constants
    const AD2BE = 543;
    const SECS_PER_DAY = 86400;
    const DATEFORMAT = 'jnY';

    const SD_FMT_FORM = 'j/n/Y';
    const SDT_FMT_FORM = 'j/n/Y H:i:s';

    const SD_FMT_TH = 'j M y';
    const LD_FMT_TH = 'j F Y';
    const SDT_FMT_TH = 'j M y, H:i น.';
    const LDT_FMT_TH = 'j F Y, H:i น.';
    const ST_FMT_TH = 'H:i น.';
    const ST_FMT_TWOPOSITION_FORM = 'H:i';

    const SQL_DT_FMT = 'Y-m-d H:i:s';
    const SQL_D_FMT = 'Y-m-d';

    const NUMERIC_FORMAT_DAY = 'N';

    const MON_NUMERIC =1;
    const TUE_NUMERIC =2;
    const WED_NUMERIC =3;
    const THU_NUMERIC =4;
    const FRI_NUMERIC =5;
    const SAT_NUMERIC =6;
    const SUN_NUMERIC =7;

    const HALF_DAY_BREAKFAST = 0;
    const HALF_DAY_AFTERNOON = 1;

    public static $arrDayNumeric = array(
        self::MON_NUMERIC => 1,
        self::TUE_NUMERIC => 2,
        self::WED_NUMERIC => 3,
        self::THU_NUMERIC => 4,
        self::FRI_NUMERIC => 5,
        self::SAT_NUMERIC => 6,
        self::SUN_NUMERIC => 7,
    );
}
?>