dateobject.php

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<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to [e-mail] so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Date
 * @copyright  Copyright (c) 2005-2007 Zend Technologies USA Inc. (http://www.zend.com)
 * @version    $Id: DateObject.php 3877 2007-03-12 21:24:41Z thomas $
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */


/**
 * Include needed Date classes
 */
require_once 'Zend/Date/Exception.php';

/**
 * @category   Zend
 * @package    Zend_Date
 * @subpackage Zend_Date_DateObject
 * @copyright  Copyright (c) 2005-2007 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
abstract class Zend_Date_DateObject {


    /**
     * UNIX Timestamp
     */
    private $_unixTimestamp;


    /**
     * active timezone
     */
    private $_timezone = 'UTC';
    private $_offset   = 0;
    private $_syncronised = 0;


    /**
     * Table of Monthdays
     */
    private static $_monthTable = array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);


    /**
     * Table of Years
     */
    private static $_yearTable = array(
        1970 => 0,            1960 => -315619200,   1950 => -631152000,
        1940 => -946771200,   1930 => -1262304000,  1920 => -1577923200,
        1910 => -1893456000,  1900 => -2208988800,  1890 => -2524521600,
        1880 => -2840140800,  1870 => -3155673600,  1860 => -3471292800,
        1850 => -3786825600,  1840 => -4102444800,  1830 => -4417977600,
        1820 => -4733596800,  1810 => -5049129600,  1800 => -5364662400,
        1790 => -5680195200,  1780 => -5995814400,  1770 => -6311347200,
        1760 => -6626966400,  1750 => -6942499200,  1740 => -7258118400,
        1730 => -7573651200,  1720 => -7889270400,  1710 => -8204803200,
        1700 => -8520336000,  1690 => -8835868800,  1680 => -9151488000,
        1670 => -9467020800,  1660 => -9782640000,  1650 => -10098172800,
        1640 => -10413792000, 1630 => -10729324800, 1620 => -11044944000,
        1610 => -11360476800, 1600 => -11676096000);


    /**
     * Set this object to have a new UNIX timestamp.
     *
     * @param  string|integer  $timestamp  OPTIONAL timestamp; defaults to local time using time()
     * @return string|integer  old timestamp 
     * @throws Zend_Date_Exception
     */
    protected function setUnixTimestamp($timestamp = null)
    {
        $old = $this->_unixTimestamp;

        if (is_numeric($timestamp)) {
            $this->_unixTimestamp = $timestamp;
        } else if ($timestamp === null) {
            $this->_unixTimestamp = time();
        } else {
            throw new Zend_Date_Exception('\'' . $timestamp . '\' is not a valid UNIX timestamp', $timestamp);
        }

        return $old;
    }


    /**
     * Returns this object's UNIX timestamp
     * A timestamp greater then the integer range will be returned as string
     * This function does not return the timestamp as object. Use copy() instead. 
     *
     * @return  integer|string  timestamp
     */
    protected function getUnixTimestamp()
    {
        if ($this->_unixTimestamp === intval($this->_unixTimestamp)) {
            return (int) $this->_unixTimestamp;
        } else {
            return (string) $this->_unixTimestamp;
        }
    }

    /**
     * Internal function.
     * Returns time().  This method exists to allow unit tests to work-around methods that might otherwise
     * be hard-coded to use time().  For example, this makes it possible to test isYesterday() in Date.php.
     *
     * @param   integer  $sync      OPTIONAL time syncronisation value
     * @return  integer  timestamp
     */
    protected function _getTime($sync = null)
    {
        if ($sync !== null) {
            $this->_syncronised = round($sync);
        }
        return (time() + $this->_syncronised);
    }


    /**
     * Internal mktime function used by Zend_Date.
     * The timestamp returned by mktime() can exceed the precision of traditional UNIX timestamps, 
     * by allowing PHP to auto-convert to using a float value.
     *
     * Returns a timestamp relative to 1970/01/01 00:00:00 GMT/UTC.
     * DST (Summer/Winter) is depriciated since php 5.1.0.
     * Year has to be 4 digits otherwise it would be recognised as
     * year 70 AD instead of 1970 AD as expected !!
     *
     * @param  integer  $hour
     * @param  integer  $minute 
     * @param  integer  $second
     * @param  integer  $month
     * @param  integer  $day
     * @param  integer  $year
     * @param  boolean  $gmt     OPTIONAL true = other arguments are for UTC time, false = arguments are for local time/date
     * @return  integer|float  timestamp (number of seconds elapsed relative to 1970/01/01 00:00:00 GMT/UTC)
     */
    protected function mktime($hour, $minute, $second, $month, $day, $year, $gmt = false)
    {
        // complete date but in 32bit timestamp - use PHP internal
        if ((1901 < $year) and ($year < 2038)) {

            $oldzone = @date_default_timezone_get();
            // Timezone also includes DST settings, therefor substracting the GMT offset is not enough
            // We have to set the correct timezone to get the right value
            if (($this->_timezone != $oldzone) and ($gmt === false)) {
                $second -= $this->_offset;
                date_default_timezone_set($this->_timezone);
            }

            $result = ($gmt) ? @gmmktime($hour, $minute, $second, $month, $day, $year) 
                             :   @mktime($hour, $minute, $second, $month, $day, $year);
            date_default_timezone_set($oldzone);

            return $result;
        }

        // after here we are handling 64bit timestamps
        // get difference from local to gmt
        $difference = ($gmt) ? 0 
                             : $this->_offset;

        // date to integer
        $day   = intval($day);
        $month = intval($month);
        $year  = intval($year);

        // correct months > 12 and months < 1
        if ($month > 12) {
            $overlap = floor($month / 12);
            $year   += $overlap;
            $month  -= $overlap * 12;
        } else {
            $overlap = ceil((1 - $month) / 12);
            $year   -= $overlap;
            $month  += $overlap * 12;
        }

        $date = 0;
        if ($year >= 1970) {

            // Date is after UNIX epoch
            // go through leapyears
            // add months from letest given year
            for ($count = 1970; $count <= $year; $count++) {
                $leapyear = self::isYearLeapYear($count);
                if ($count < $year) {

                    $date += 365;
                    if ($leapyear === true) {
                        $date++;
                    }

                } else {

                    for ($mcount = 0; $mcount < ($month - 1); $mcount++) {
                        $date += self::$_monthTable[$mcount];
                        if (($leapyear === true) and ($mcount == 1)) {
                            $date++;
                        }

                    }
                }
            }

            $date += $day - 1;

            return (($date * 86400) + ($hour * 3600) + ($minute * 60) + $second + $difference);
        } else {
            
            // Date is before UNIX epoch
            // go through leapyears
            // add months from latest given year
            for ($count = 1969; $count >= $year; $count--) {

                $leapyear = self::isYearLeapYear($count);
                if ($count > $year)
                {
                    $date += 365;
                    if ($leapyear === true)
                        $date++;
                } else {

                    for ($mcount = 11; $mcount > ($month - 1); $mcount--) {
                        $date += self::$_monthTable[$mcount];
                        if (($leapyear === true) and ($mcount == 1)) {
                            $date++;
                        }

                    }
                }
            }

            $date += (self::$_monthTable[$month - 1] - $day);
            $date = -(($date * 86400) + (86400 - (($hour * 3600) + ($minute * 60) + $second)) + $difference);

            // gregorian correction for 5.Oct.1582
            if ($date < -12220185600) {
                $date += 864000;
            } else if ($date < -12219321600) {
                $date  = -12219321600;
            }

            return $date;
        }
    }


    /**
     * Returns true, if given $year is a leap year.
     *
     * @param  integer  $year
     * @return boolean  true, if year is leap year
     */
    protected static function isYearLeapYear($year)
    {
        // all leapyears can be divided through 4
        if (($year % 4) != 0) {
            return false;
        }

        // all leapyears can be divided through 400 
        if ($year % 400 == 0) {
            return true;
        } else if (($year > 1582) and ($year % 100 == 0)) {
            return false;
        }

        return true;
    }


    /**
     * Internal mktime function used by Zend_Date for handling 64bit timestamps.
     *
     * Returns a formatted date for a given timestamp.
     *
     * @param  string   $format     format for output
     * @param  mixed    $timestamp
     * @param  boolean  $gmt        OPTIONAL true = other arguments are for UTC time, false = arguments are for local time/date
     * @return string
     */
    protected function date($format, $timestamp = null, $gmt = false)
    {
        if ($timestamp === null) {

            $oldzone = @date_default_timezone_get();
            if ($this->_timezone != $oldzone) {
                date_default_timezone_set($this->_timezone);
            }

            $result = ($gmt) ? @gmdate($format) : @date($format);
            date_default_timezone_set($oldzone);

            return $result;
        }

        if (abs($timestamp) <= 0x7FFFFFFF) {

            $oldzone = @date_default_timezone_get();
            if ($this->_timezone != $oldzone) {
                date_default_timezone_set($this->_timezone);
            }

            $result = ($gmt) ? @gmdate($format, $timestamp) : @date($format, $timestamp);
            date_default_timezone_set($oldzone);

            return $result;
        }

        // check on false or null alone failes
        if (empty($gmt)) {
            $timestamp -= $this->_offset;
        }
        
        $date = $this->getDateParts($timestamp, true);
        $length = strlen($format);
        $output = '';
        
        for ($i = 0; $i < $length; $i++) {

            switch($format[$i]) {

                // day formats