<?php

/**
 * This source file is subject to version 2.02 of the PHP license,
 * that is bundled with this package in the file LICENSE, and is
 * available at through the world-wide-web at
 * http://www.php.net/license/2_02.txt.
 * If you did not receive a copy of the PHP license and are unable to
 * obtain it through the world-wide-web, please send a note to
 * license@php.net so we can mail you a copy immediately.
 *
 * Copyright (c) 1999, 2002, 2003 ispi
 *
 * @access public
 *
 * @version 1.2.6
 * @author Monte Ohrt <monte@ispi.net>
 */

// The constant telling us what day starts the week. Monday (1) is
// the international standard. Redefine this to 0 if you want weeks
// to begin on Sunday.

define('DATE_CALC_BEGIN_WEEKDAY',1);


/**
 * Returns the current local date. NOTE: This function
 * retrieves the local date using strftime(), which may
 * or may not be 32-bit safe on your system.
 *
 * @param string the strftime() format to return the date
 *
 * @access public
 *
 * @return string the current date in specified format
 */

function date_now($format='%Y%m%d')	{
	return(strftime($format,now()));

} // end func date_now


/**
 *	Formats the date in the given format, much like
 *	strfmt(). This function is used to alleviate the
 *	problem with 32-bit numbers for dates pre 1970
 *	or post 2038, as strfmt() has on most systems.
 *	Most of the formatting options are compatible.
 *
 *	formatting options:
 *
 *	%a		abbreviated weekday name (Sun, Mon, Tue)
 *	%A		full weekday name (Sunday, Monday, Tuesday)
 *	%b		abbreviated month name (Jan, Feb, Mar)
 *	%B		full month name (January, February, March)
 *	%d		day of month (range 00 to 31)
 *	%e		day of month, single digit (range 0 to 31)
 *	%E		number of days since unspecified epoch (integer)
 *			 (%E is useful for passing a date in a URL as
 *			 an integer value. Then simply use
 *			 days_to_date() to convert back to a date.)
 *	%j		day of year (range 001 to 366)
 *	%m		month as decimal number (range 1 to 12)
 *	%n		newline character (\n)
 *	%t		tab character (\t)
 *	%w		weekday as decimal (0 = Sunday)
 *	%U		week number of current year, first sunday as first week
 *	%y		year as decimal (range 00 to 99)
 *	%Y		year as decimal including century (range 0000 to 9999)
 *	%%		literal '%'
 *
 * @param string year in format CCYY
 * @param string month in format MM
 * @param string day in format DD
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function dateformat($day,$month,$year,$format) {
	if(!is_valid_date($day,$month,$year)) {
		$year = date_now('%Y');
		$month = date_now('%m');
		$day = date_now('%d');
	}

	$output = '';

	for($strpos = 0; $strpos < strlen($format); $strpos++) {
		$char = substr($format,$strpos,1);
		if($char == '%') {
			$nextchar = substr($format,$strpos + 1,1);
			switch($nextchar) {
				case 'a':
					$output .= get_weekday_abbrname($day,$month,$year);
					break;
				case 'A':
					$output .= get_weekday_fullname($day,$month,$year);
					break;
				case 'b':
					$output .= get_month_abbrname($month);
					break;
				case 'B':
					$output .= get_month_fullname($month);
					break;
				case 'd':
					$output .= sprintf('%02d',$day);
					break;
				case 'e':
					$output .= $day;
					break;
				case 'E':
					$output .= date_to_days($day,$month,$year);
					break;
				case 'j':
					$output .= julian_date($day,$month,$year);
					break;
				case 'm':
					$output .= sprintf('%02d',$month);
					break;
				case 'n':
					$output .= "\n";
					break;
				case 't':
					$output .= "\t";
					break;
				case 'w':
					$output .= day_of_week($day,$month,$year);
					break;
				case 'U':
					$output .= week_of_year($day,$month,$year);
					break;
				case 'y':
					$output .= substr($year,2,2);
					break;
				case 'Y':
					$output .= $year;
					break;
				case '%':
					$output .= '%';
					break;
				default:
					$output .= $char.$nextchar;
			}
			$strpos++;
		}
		else {
			$output .= $char;
		}
	}
	return $output;

} // end func date_format


/**
 * Converts a date to number of days since a
 * distant unspecified epoch.
 *
 * @param string year in format CCYY
 * @param string month in format MM
 * @param string day in format DD
 *
 * @access public
 *
 * @return integer number of days
 */

function date_to_days($day,$month,$year) {

	$century = substr($year,0,2);
	$year = substr($year,2,2);

	if($month > 2) $month -= 3;
	else {
		$month += 9;
		if($year) $year--;
		else {
			$year = 99;
			$century--;
		}
	}

	return (floor(( 146097 * $century) / 4 ) +
			floor(( 1461 * $year) / 4 ) +
			floor(( 153 * $month + 2) / 5 ) +
				$day + 1721119);

} // end func date_to_days


/**
 * Converts number of days to a distant unspecified epoch.
 *
 * @param int number of days
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in specified format
 */

function days_to_date($days,$format='%Y-%m-%d') {

	$days	 -= 1721119;
	$century = floor(( 4 * $days - 1) / 146097);
	$days	 = floor(4 * $days - 1 - 146097 * $century);
	$day	 = floor($days / 4);

	$year	 = floor(( 4 * $day + 3) / 1461);
	$day	 = floor(4 * $day + 3 - 1461 * $year);
	$day	 = floor(($day + 4) / 4);

	$month	 = floor(( 5 * $day - 3) / 153);
	$day	 = floor(5 * $day - 3 -	153 * $month);
	$day	 = floor(($day + 5) / 5);

	if($month < 10) $month +=3;
	else {
		$month -=9;
		if($year++ == 99) {
			$year = 0;
			$century++;
		}
	}

	$century = sprintf('%02d',$century);
	$year = sprintf('%02d',$year);

	return(dateformat($day,$month,$century.$year,$format));

} // end func days_to_date


 /**
 * Returns true for valid date, false for invalid date.
 *
 * @param string year in format CCYY
 * @param string month in format MM
 * @param string day in format DD
 *
 * @access public
 *
 * @return boolean true/false
 */

function is_valid_date($day, $month, $year)	{
	if(empty($year) or empty($month) or empty($day)) return false;

	// must be digits only
	if(preg_match('/\D/',$year)) return false;
	if(preg_match('/\D/',$month)) return false;
	if(preg_match('/\D/',$day)) return false;

	if($year<0 or $year>9999) return false;
	if($month<1 or $month>12) return false;
	if($day<1 or $day>31 or $day>days_in_month($month,$year)) return false;

	return true;

} // end func is_valid_date


/**
 * Determines if given year is a leap year.
 *
 * @param string year in format CCYY
 *
 * @access public
 *
 * @return boolean true/false
 */
function is_leap_year($year='')	{
	if(empty($year)) $year=date_now('%Y');

	if(strlen($year)!=4) return false;

	if(preg_match('/\D/',$year)) return false;

	return (($year%4==0 and $year%100!=0) or $year%400==0);

} // end func is_leap_year


/**
 * Determines if given date is a future date from now.
 *
 * @param string year in format CCYY
 * @param string month in format MM
 * @param string day in format DD
 *
 * @access public
 *
 * @return boolean true/false
 */

function is_future_date($day,$month,$year) {
	$this_year=date_now('%Y');
	$this_month=date_now('%m');
	$this_day=date_now('%d');

	if($year>$this_year)
		return true;
	elseif($year==$this_year)
		if($month>$this_month)
			return true;
		elseif($month==$this_month)
			if($day>$this_day)
				return true;

	return false;

} // end func is_future_date


/**
 * Determines if given date is a past date from now.
 *
 * @param string year in format CCYY
 * @param string month in format MM
 * @param string day in format DD
 *
 * @access public
 *
 * @return boolean true/false
 */

function is_past_date($day,$month,$year) {
	$this_year=date_now('%Y');
	$this_month=date_now('%m');
	$this_day=date_now('%d');


	if($year<$this_year)
		return true;
	elseif($year==$this_year)
		if($month<$this_month)
			return true;
		elseif($month==$this_month)
			if($day<$this_day)
				return true;

	return false;

} // end func is_past_date


/**
 * Returns day of week for given date, 0=Sunday
 *
 * @param string year in format CCYY, default is current local year
 * @param string month in format MM, default is current local month
 * @param string day in format DD, default is current local day
 *
 * @access public
 *
 * @return int $weekday_number
 */

function day_of_week($day='',$month='',$year='') {
	if(empty($year))
		$year=date_now('%Y');
	if(empty($month))
		$month=date_now('%m');
	if(empty($day))
		$day=date_now('%d');
	if($month>2) {
		$month-=2;
	} else {
		$month+=10;
		$year--;
	}
	$day=(floor((13*$month-1)/5)+$day+($year%100)+floor(($year%100)/4)+floor(($year/100)/4)-2*floor($year/100)+77);
	$weekday_number=(($day-7*floor($day/7)));
	return $weekday_number;

} // end func day_of_week


/**
 * Returns week of the year, first Sunday is first day of first week
 *
 * @param string year in format CCYY
 * @param string month in format MM
 * @param string day in format DD
 *
 * @access public
 *
 * @return integer $week_number
 */

function week_of_year($day,$month,$year) {
	if(empty($year))
		$year=date_now('%Y');
	if(empty($month))
		$month=date_now('%m');
	if(empty($day))
		$day=date_now('%d');

	$week_year=$year-1501;
	$weekday=$week_year*365+floor($week_year/4)-29872+1-floor($week_year/100)+floor(($week_year-300)/400);

	$week_number=floor((julian_date($day,$month,$year)+floor(($weekday+4)%7))/7);

	return $week_number;

} // end func week_of_year


/**
 * Returns number of days since 31 December of year before given date.
 *
 * @param string year in format CCYY, default is current local year
 * @param string month in format MM, default is current local month
 * @param string day in format DD, default is current local day
 *
 * @access public
 *
 * @return int $julian
 */

function julian_date($day='',$month='',$year='') {
	if(empty($year)) $year=date_now('%Y');
	if(empty($month)) $month=date_now('%m');
	if(empty($day)) $day=date_now('%d');

	$days=array(0,31,59,90,120,151,181,212,243,273,304,334);

	$julian=($days[$month-1]+$day);

	if($month>2 and is_leap_year($year)) $julian++;

	return($julian);

} // end func julian_date


/**
 * Returns quarter of the year for given date
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 *
 * @access public
 *
 * @return int $year_quarter
 */

function quarter_of_year($day='',$month='',$year='') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$year_quarter=(intval(($month-1)/3+1));

	return $year_quarter;

} // end func quarter_of_year


/**
 * Returns date of begin of next month of given date.
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function begin_of_next_month($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	if($month < 12) {
		$month++;
		$day=1;
	} else {
		$year++;
		$month=1;
		$day=1;
	}

	return dateformat($day,$month,$year,$format);

} // end func begin_of_next_month


/**
 * Returns date of the last day of next month of given date.
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function end_of_next_month($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year=date_now('%Y');
	if(empty($month)) $month=date_now('%m');
	if(empty($day)) $day=date_now('%d');

	if($month < 12) {
		$month++;
	} else {
		$year++;
		$month=1;
	}

	$day=days_in_month($month,$year);

	return dateformat($day,$month,$year,$format);

} // end func end_of_next_month


/**
 * Returns date of the first day of previous month of given date.
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function begin_of_prev_month($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year=date_now('%Y');
	if(empty($month)) $month=date_now('%m');
	if(empty($day)) $day=date_now('%d');

	if($month > 1) {
		$month--;
		$day=1;
	} else {
		$year--;
		$month=12;
		$day=1;
	}

	return dateformat($day,$month,$year,$format);

} // end func begin_of_prev_month


/**
 * Returns date of the last day of previous month for given date.
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function end_of_prev_month($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year=date_now('%Y');
	if(empty($month)) $month=date_now('%m');
	if(empty($day)) $day=date_now('%d');

	if($month > 1) {
		$month--;
	} else {
		$year--;
		$month=12;
	}

	$day=days_in_month($month,$year);

	return dateformat($day,$month,$year,$format);

} // end func end_of_prev_month


/**
 * Returns date of the next weekday of given date,
 * skipping from Friday to Monday.
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function next_weekday($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$days = date_to_days($day,$month,$year);

	if(day_of_week($day,$month,$year) == 5) $days += 3;
	elseif(day_of_week($day,$month,$year) == 6) $days += 2;
	else $days += 1;

	return(days_to_date($days,$format));

} // end func next_weekday


/**
 * Returns date of the previous weekday,
 * skipping from Monday to Friday.
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function prev_weekday($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$days = date_to_days($day,$month,$year);

	if(day_of_week($day,$month,$year) == 1) $days -= 3;
	elseif(day_of_week($day,$month,$year) == 0) $days -= 2;
	else $days -= 1;

	return(days_to_date($days,$format));

} // end func prev_weekday


/**
 * Returns date of the next specific day of the week
 * from the given date.
 *
 * @param int day of week, 0=Sunday
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param boolean onOrAfter if true and days are same, returns current day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function next_day_of_week($dow,$day='',$month='',$year='',$format='%Y%m%d',$on_or_after=false) {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$days = date_to_days($day,$month,$year);
	$curr_weekday = day_of_week($day,$month,$year);

	if($curr_weekday == $dow) {
		if(!$on_or_after) $days += 7;
	}
	elseif($curr_weekday > $dow) $days += 7 - ( $curr_weekday - $dow );
	else $days += $dow - $curr_weekday;

	return(days_to_date($days,$format));

} // end func next_day_of_week


/**
 * Returns date of the previous specific day of the week
 * from the given date.
 *
 * @param int day of week, 0=Sunday
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param boolean onOrBefore if true and days are same, returns current day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function prev_day_of_week($dow,$day='',$month='',$year='',$format='%Y%m%d',$on_or_before=false) {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$days = date_to_days($day,$month,$year);
	$curr_weekday = day_of_week($day,$month,$year);

	if($curr_weekday == $dow) {
		if(!$on_or_before) $days -= 7;
	} elseif($curr_weekday < $dow) {
		$days -= 7 - ( $dow - $curr_weekday );
	} else {
		$days -= $curr_weekday - $dow;
	}

	return(days_to_date($days,$format));

} // end func prev_day_of_week


/**
 * Returns date of the next specific day of the week
 * on or before the given date.
 *
 * @param int day of week, 0=Sunday
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function next_day_of_week_on_or_after($dow,$day='',$month='',$year='',$format='%Y%m%d') {
	return(next_day_of_week($dow,$day='',$month='',$year='',$format='%Y%m%d',true));
} // end func next_day_of_week_on_or_after


/**
 * Returns date of the previous specific day of the week
 * on or before the given date.
 *
 * @param int day of week, 0=Sunday
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function prev_day_of_week_on_or_before($dow,$day='',$month='',$year='',$format='%Y%m%d') {
	return(prev_day_of_week($dow,$day='',$month='',$year='',$format='%Y%m%d',true));

} // end func prev_day_of_week_on_or_after


/**
 * Returns date of day after given date.
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function next_day($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$days = date_to_days($day,$month,$year);

	return(days_to_date($days + 1,$format));

} // end func next_day


/**
 * Returns date of day before given date.
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function prev_day($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$days = date_to_days($day,$month,$year);

	return(days_to_date($days - 1,$format));

} // end func prev_day


/**
 * Sets century for 2 digit year.
 * 51-99 is 19, else 20
 *
 * @param string 2 digit year
 *
 * @access public
 *
 * @return string 4 digit year
 */

function default_century($year) {
	if(strlen($year)==1) $year="0$year";
	if($year>50) return("19$year");
	else return("20$year");

} // end func default_century


/**
 * Returns number of days between two given dates.
 *
 * @param string year in format CCYY
 * @param string month in format MM
 * @param string day in format DD
 * @param string year in format CCYY
 * @param string month in format MM
 * @param string day in format DD
 *
 * @access public
 *
 * @return int absolute number of days between dates,
 *		-1 if there is an error.
 */

function date_diff($day1,$month1,$year1,$day2,$month2,$year2) {
	if(!is_valid_date($day1,$month1,$year1)) return -1;
	if(!is_valid_date($day2,$month2,$year2)) return -1;

	return(abs((date_to_days($day1,$month1,$year1))
				- (date_to_days($day2,$month2,$year2))));

} // end func date_diff


/**
 * Find the number of days in the given month.
 *
 * @param string month in format MM, default current local month
 *
 * @access public
 *
 * @return int number of days
 */

function days_in_month($month='',$year='') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');

	if($month == 2) {
		if(is_leap_year($year)) return 29;
		else return 28;
	}
	elseif($month == 4 or $month == 6 or $month == 9 or $month == 11) return 30;
	else return 31;

} // end func days_in_month


/**
 * Returns the number of rows on a calendar month. Useful for
 * determining the number of rows when displaying a typical
 * month calendar.
 *
 * @param string month in format MM, default current local month
 * @param string year in format YYCC, default current local year
 *
 * @access public
 *
 * @return int number of weeks
 */

function weeks_in_month($month='',$year='') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');

	if(DATE_CALC_BEGIN_WEEKDAY == 1) {

		if(first_of_month_weekday($month,$year) == 0) $first_weekdays = 1;
		else $first_weekdays = 7 - (first_of_month_weekday($month,$year) - 1);

	}	else {
		$first_weekdays = 7 - first_of_month_weekday($month,$year);
	}

	return ceil(((days_in_month($month,$year) - $first_weekdays) / 7) + 1);

} // end func weeks_in_month


/**
 * Find the day of the week for the first of the month of given date.
 *
 * @param string year in format CCYY, default to current local year
 * @param string month in format MM, default to current local month
 *
 * @access public
 *
 * @return int number of weekday for the first day, 0=Sunday
 */

function first_of_month_weekday($month='',$year='') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	return(day_of_week('01',$month,$year));
} // end func first_of_month_weekday


/**
 * Return date of first day of month of given date.
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function begin_of_month($month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	return(dateformat('01',$month,$year,$format));

} // end of func begin_of_month


/**
 * Find the month day of the beginning of week for given date,
 * using DATE_CALC_BEGIN_WEEKDAY. (can return weekday of prev month.)
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function begin_of_week($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$this_weekday = day_of_week($day,$month,$year);

if(DATE_CALC_BEGIN_WEEKDAY == 1) {
	if($this_weekday == 0) $begin_of_week = date_to_days($day,$month,$year) - 6;
	else $begin_of_week = date_to_days($day,$month,$year) - $this_weekday + 1;
} else {
	$begin_of_week = (date_to_days($day,$month,$year) - $this_weekday);
}

	 /*	$begin_of_week = (date_to_days($day,$month,$year)
		- ($this_weekday - DATE_CALC_BEGIN_WEEKDAY)); */

	return(days_to_date($begin_of_week,$format));

} // end of func begin_of_week


/**
 * Find the month day of the end of week for given date,
 * using DATE_CALC_BEGIN_WEEKDAY. (can return weekday
 * of following month.)
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function end_of_week($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$this_weekday = day_of_week($day,$month,$year);

	$last_day_of_week = (date_to_days($day,$month,$year)
		+ (6 - $this_weekday + DATE_CALC_BEGIN_WEEKDAY));

	return(days_to_date($last_day_of_week,$format));

} // end func end_of_week


/**
 * Find the month day of the beginning of week after given date,
 * using DATE_CALC_BEGIN_WEEKDAY. (can return weekday of prev month.)
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function begin_of_next_week($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$date = days_to_date(date_to_days($day+7,$month,$year),'%Y%m%d');

	$next_week_year = substr($date,0,4);
	$next_week_month = substr($date,4,2);
	$next_week_day = substr($date,6,2);

	$this_weekday = day_of_week($next_week_day,$next_week_month,$next_week_year);

	$begin_of_week = (date_to_days($next_week_day,$next_week_month,$next_week_year) - ($this_weekday - DATE_CALC_BEGIN_WEEKDAY));

	return(days_to_date($begin_of_week,$format));

} // end func begin_of_next_week


/**
 * Find the month day of the beginning of week before given date,
 * using DATE_CALC_BEGIN_WEEKDAY. (can return weekday of prev month.)
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function begin_of_prev_week($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$date = days_to_date(date_to_days($day-7,$month,$year),'%Y%m%d');

	$next_week_year = substr($date,0,4);
	$next_week_month = substr($date,4,2);
	$next_week_day = substr($date,6,2);

	$this_weekday = day_of_week($next_week_day,$next_week_month,$next_week_year);

	$begin_of_week = (date_to_days($next_week_day,$next_week_month,$next_week_year) - ($this_weekday - DATE_CALC_BEGIN_WEEKDAY));

	return(days_to_date($begin_of_week,$format));

} // end func begin_of_prev_week


/**
 * Return an array with days in week
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param string format for returned date
 *
 * @access public
 *
 * @return array $week[$weekday]
 */

function get_calendar_week($day='',$month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$week_array = array();

	// date for the column of week

	$curr_day = begin_of_week($day,$month,$year,'%E');

		for($counter=0; $counter <= 6; $counter++) {
			$week_array[$counter] = days_to_date($curr_day,$format);
			$curr_day++;
		}

	return $week_array;

} // end func get_calendar_week


/**
 * Return a set of arrays to construct a calendar month for
 * the given date.
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string format for returned date
 *
 * @access public
 *
 * @return array $month[$row][$col]
 */

function get_calendar_month($month='',$year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');

	$month_array = array();

	// date for the first row, first column of calendar month
	if(DATE_CALC_BEGIN_WEEKDAY == 1) {
		if(first_of_month_weekday($month,$year) == 0) {
			$curr_day = date_to_days('01',$month,$year) - 6;
		} else {
			$curr_day = date_to_days('01',$month,$year)
				- first_of_month_weekday($month,$year) + 1;
		}
	} else {
			$curr_day = (date_to_days('01',$month,$year)
				- first_of_month_weekday($month,$year));
	}

	// number of days in this month
	$days_in_month = days_in_month($month,$year);

	$weeks_in_month = weeks_in_month($month,$year);
	for($row_counter=0; $row_counter < $weeks_in_month; $row_counter++) {
		for($column_counter=0; $column_counter <= 6; $column_counter++) {
			$month_array[$row_counter][$column_counter] = days_to_date($curr_day,$format);
			$curr_day++;
		}
	}

	return $month_array;

} // end func get_calendar_month


/**
 * Return a set of arrays to construct a calendar year for
 * the given date.
 *
 * @param string year in format CCYY, default current local year
 * @param string format for returned date
 *
 * @access public
 *
 * @return array $year[$month][$row][$col]
 */

function get_calendar_year($year='',$format='%Y%m%d') {
	if(empty($year)) $year = date_now('%Y');

	$year_array = array();

	for($curr_month=0; $curr_month <=11; $curr_month++)
		$year_array[$curr_month] = get_calendar_month(sprintf('%02d',$curr_month+1),$year,$format);

	return $year_array;

} // end func get_calendar_year


/**
 * Calculates the date of the Nth weekday of the month,
 * such as the second Saturday of January 2000.
 *
 * @param string occurance: 1=first, 2=second, 3=third, etc.
 * @param string day_of_week: 0=Sunday, 1=Monday, etc.
 * @param string year in format CCYY
 * @param string month in format MM
 * @param string format for returned date
 *
 * @access public
 *
 * @return string date in given format
 */

function n_weekday_of_month($occurance,$day_of_week,$month,$year,$format='%Y%m%d') {

	$year = sprintf('%04d',$year);
	$month = sprintf('%02d',$month);

	$DOW1day = sprintf('%02d',(($occurance - 1) * 7 + 1));
	$DOW1 = day_of_week($DOW1day,$month,$year);

	$wdate = ($occurance - 1) * 7 + 1 +
			(7 + $day_of_week - $DOW1) % 7;

	if( $wdate > days_in_month($month,$year)) return -1;
	else return(dateformat($wdate,$month,$year,$format));

} // end func n_weekday_of_month


/**
 * Returns the current local year in format CCYY
 *
 * @access public
 *
 * @return string year in format CCYY
 */

function get_year() {
	return date_now('%Y');

} // end func get_year


/**
 * Returns the current local month in format MM
 *
 * @access public
 *
 * @return string month in format MM
 */

function get_month() {
	return date_now('%m');

} // end func get_month

/**
 * Returns the current local day in format DD
 *
 * @access public
 *
 * @return string day in format DD
 */

function get_day() {
	return date_now('%d');

} // end func get_day


/**
 * Returns the full month name for the given month
 *
 * @param string month in format MM
 *
 * @access public
 *
 * @return string full month name
 */

function get_month_fullname($month) {
	if(empty($month)) $month = date_now('%m');

	$month_names = array('January','February','March','April','May','June','July','August','September','October','November','December');

	return $month_names[($month - 1)];

} // end func get_month_fullname


/**
 * Returns the abbreviated month name for the given month
 *
 * @param string month in format MM
 * @param int optional length of abbreviation, default is 3
 *
 * @access public
 *
 * @return string abbreviated month name
 */

function get_month_abbrname($month,$length=3) {
	if(empty($month)) $month = date_now('%m');

	$month_names = array('January','February','March','April','May','June','July','August','September','October','November','December');

	return substr($month_names[($month - 1)],0,$length);

} // end func get_month_abbrname


/**
 * Returns the full weekday name for the given date
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 *
 * @access public
 *
 * @return string full month name
 */

function get_weekday_fullname($day='',$month='',$year='') {
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$weekday_names = array('Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday');

	return $weekday_names[$weekday];

} // end func get_weekday_fullname


/**
 * Returns the abbreviated weekday name for the given date
 *
 * @param string year in format CCYY, default current local year
 * @param string month in format MM, default current local month
 * @param string day in format DD, default current local day
 * @param int optional length of abbreviation, default is 3
 *
 * @access public
 *
 * @return string full month name
 */

function get_weekday_abbrname($day='',$month='',$year='',$length=3)	{
	if(empty($year)) $year = date_now('%Y');
	if(empty($month)) $month = date_now('%m');
	if(empty($day)) $day = date_now('%d');

	$weekday_names = array('Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday');

	$weekday = day_of_week($day,$month,$year);

	return substr($weekday_names[$weekday],0,$length);

} // end func get_weekday_fullname

?>