<?xml version="1.0" encoding="utf-8"?>
<reference id="ref.calendar">
	<title>Calendar functions</title>
	<titleabbrev>Calendar</titleabbrev>
	<partintro>
		<para>
	이 함수는 PHP 소스코드의 "dl"이나 "ext" 디렉토리에 있는 
	calender extension을 함께 사용하도록 컴파일하여야 사용가능하다. 
	사용전에 꼭 README 파일을 읽어보라. 
   </para>
		<para>
	PHP에는 서로 다른 날짜(달력) 형태를 변환시켜 주는 함수들을 제공한다. 
	Julian Day Count가 기본이 된다. 이것은 BC4000년의 어느 시점을 기준으로 잡아 
	그곳에서부터 얼마의 날짜가 지났는 가를 기준으로 삼는 것이다. 
	이 Julian Day Count는 일반적으로 사용하는 Julian 시스템과는 다르다는 것을 알아두자. 
	Calendar 시스템에 대해 자세히 알고 싶다면 <ulink url="&url.calendar;">&url.calendar;</ulink>을 방문하여 보라. 
	이 설명서중에서는 위의 페이지에서 발췌된 내용을 ""로 둘러 싸고 있다.
   </para>
	</partintro>
	<refentry id="function.jdtogregorian">
		<refnamediv>
			<refname>JDToGregorian</refname>
			<refpurpose>Converts Julian Day Count to Gregorian date</refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>string</type><methodname>jdtogregorian</methodname>
					<methodparam><type>int</type><parameter>julianday</parameter></methodparam>
				</methodsynopsis>
			<para>
     Converts Julian Day Count to a string containing the Gregorian
     date in the format of "month/day/year".
    </para>
		</refsect1>
	</refentry>
	<refentry id="function.gregoriantojd">
		<refnamediv>
			<refname>GregorianToJD</refname>
			<refpurpose>
     Converts a Gregorian date to Julian Day Count
    </refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>int</type><methodname>gregoriantojd</methodname>
					<methodparam><type>int</type><parameter>month</parameter></methodparam>
					<methodparam><type>int</type><parameter>day</parameter></methodparam>
					<methodparam><type>int</type><parameter>year</parameter></methodparam>
				</methodsynopsis>
			<para>
     Valid Range for Gregorian Calendar 4714 B.C. to 9999 A.D.</para>
			<para>
     Although this software can handle dates all the way back to 4714
     B.C., such use may not be meaningful. The Gregorian calendar was
     not instituted until October 15, 1582 (or October 5, 1582 in the
     Julian calendar). Some countries did not accept it until much
     later. For example, Britain converted in 1752, The USSR in 1918
     and Greece in 1923. Most European countries used the Julian
     calendar prior to the Gregorian.
     <example>
					<title>Calendar functions</title>
					<programlisting role="php">
&lt;?php
$jd = GregorianToJD (10,11,1970);
echo "$jd\n";
$gregorian = JDToGregorian ($jd);
echo "$gregorian\n";
?>
      </programlisting>
				</example>
			</para>
		</refsect1>
	</refentry>
	<refentry id="function.jdtojulian">
		<refnamediv>
			<refname>JDToJulian</refname>
			<refpurpose>
     Converts a Julian Day Count to a Julian Calendar Date
    </refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>string</type><methodname>jdtojulian</methodname>
					<methodparam><type>int</type><parameter>julianday</parameter></methodparam>
				</methodsynopsis>
			<para>
     Converts Julian Day Count to a string containing the Julian
     Calendar Date in the format of "month/day/year".
    </para>
		</refsect1>
	</refentry>
	<refentry id="function.juliantojd">
		<refnamediv>
			<refname>JulianToJD</refname>
			<refpurpose>
     Converts a Julian Calendar date to Julian Day Count
    </refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>int</type><methodname>juliantojd</methodname>
					<methodparam><type>int</type><parameter>month</parameter></methodparam>
					<methodparam><type>int</type><parameter>day</parameter></methodparam>
					<methodparam><type>int</type><parameter>year</parameter></methodparam>
				</methodsynopsis>
			<para>
     Valid Range for Julian Calendar 4713 B.C. to 9999 A.D.
    </para>
			<para>
     Although this software can handle dates all the way back to 4713
     B.C., such use may not be meaningful. The calendar was created in
     46 B.C., but the details did not stabilize until at least 8 A.D.,
     and perhaps as late at the 4th century. Also, the beginning of a
     year varied from one culture to another - not all accepted
     January as the first month.
    </para>
		</refsect1>
	</refentry>
	<refentry id="function.jdtojewish">
		<refnamediv>
			<refname>JDToJewish</refname>
			<refpurpose>
     Converts a Julian Day Count to the Jewish Calendar
    </refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>string</type><methodname>jdtojewish</methodname>
					<methodparam><type>int</type><parameter>julianday</parameter></methodparam>
				</methodsynopsis>
			<para>
     Converts a Julian Day Count the the Jewish Calendar.
    </para>
		</refsect1>
	</refentry>
	<refentry id="function.jewishtojd">
		<refnamediv>
			<refname>JewishToJD</refname>
			<refpurpose>
     Converts a date in the Jewish Calendar to Julian Day Count
    </refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>int</type><methodname>jewishtojd</methodname>
					<methodparam><type>int</type><parameter>month</parameter></methodparam>
					<methodparam><type>int</type><parameter>day</parameter></methodparam>
					<methodparam><type>int</type><parameter>year</parameter></methodparam>
				</methodsynopsis>
			<para>
     Valid Range Although this software can handle dates all the way
     back to the year 1 (3761 B.C.), such use may not be meaningful.
    </para>
			<para>
     The Jewish calendar has been in use for several thousand years,
     but in the early days there was no formula to determine the start
     of a month. A new month was started when the new moon was first
     observed.
    </para>
		</refsect1>
	</refentry>
	<refentry id="function.jdtofrench">
		<refnamediv>
			<refname>JDToFrench</refname>
			<refpurpose>
     Converts a Julian Day Count to the French Republican Calendar
    </refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>string</type><methodname>jdtofrench</methodname>
					<methodparam><type>int</type><parameter>juliandaycount</parameter></methodparam>
				</methodsynopsis>
			<para>
     Converts a Julian Day Count to the French Republican Calendar.
    </para>
		</refsect1>
	</refentry>
	<refentry id="function.frenchtojd">
		<refnamediv>
			<refname>FrenchToJD</refname>
			<refpurpose>
     Converts a date from the French Republican Calendar to a Julian
     Day Count
    </refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>int</type><methodname>frenchtojd</methodname>
					<methodparam><type>int</type><parameter>month</parameter></methodparam>
					<methodparam><type>int</type><parameter>day</parameter></methodparam>
					<methodparam><type>int</type><parameter>year</parameter></methodparam>
				</methodsynopsis>
			<para>
     Converts a date from the French Republican Calendar to a Julian
     Day Count.
    </para>
			<para>
     These routines only convert dates in years 1 through 14
     (Gregorian dates 22 September 1792 through 22 September
     1806). This more than covers the period when the calendar was in
     use.
    </para>
		</refsect1>
	</refentry>
	<refentry id="function.jdmonthname">
		<refnamediv>
			<refname>JDMonthName</refname>
			<refpurpose>Returns a month name</refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>string</type><methodname>jdmonthname</methodname>
					<methodparam><type>int</type><parameter>julianday</parameter></methodparam>
					<methodparam><type>int</type><parameter>mode</parameter></methodparam>
				</methodsynopsis>
			<para>
     Returns a string containing a month name.
     <parameter>mode</parameter> tells this function which calendar to
     convert the Julian Day Count to, and what type of month names are
     to be returned.
     <table>
					<title>Calendar modes</title>
					<tgroup cols="2">
						<thead>
							<row>
								<entry>Mode</entry>
								<entry>Meaning</entry>
							</row>
						</thead>
						<tbody>
							<row>
								<entry>0</entry>
								<entry>Gregorian - abbreviated</entry>
							</row>
							<row>
								<entry>1</entry>
								<entry>Gregorian</entry>
							</row>
							<row>
								<entry>2</entry>
								<entry>Julian - abbreviated</entry>
							</row>
							<row>
								<entry>3</entry>
								<entry>Julian</entry>
							</row>
							<row>
								<entry>4</entry>
								<entry>Jewish</entry>
							</row>
							<row>
								<entry>5</entry>
								<entry>French Republican</entry>
							</row>
						</tbody>
					</tgroup>
				</table>
			</para>
		</refsect1>
	</refentry>
	<refentry id="function.jddayofweek">
		<refnamediv>
			<refname>JDDayOfWeek</refname>
			<refpurpose>Returns the day of the week</refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>mixed</type><methodname>jddayofweek</methodname>
					<methodparam><type>int</type><parameter>julianday</parameter></methodparam>
					<methodparam><type>int</type><parameter>mode</parameter></methodparam>
				</methodsynopsis>
			<para>
     Returns the day of the week.  Can return a string or an int
     depending on the mode.
     <table>
					<title>Calendar week modes</title>
					<tgroup cols="2">
						<thead>
							<row>
								<entry>Mode</entry>
								<entry>Meaning</entry>
							</row>
						</thead>
						<tbody>
							<row>
								<entry>0</entry>
								<entry>
	  Returns the day number as an int (0=sunday, 1=monday, etc)
	 </entry>
							</row>
							<row>
								<entry>1</entry>
								<entry>
	  Returns string containing the day of week
	  (english-gregorian)
	 </entry>
							</row>
							<row>
								<entry>2</entry>
								<entry>
	  Returns a string containing the abbreviated day of week
	  (english-gregorian)
	 </entry>
							</row>
						</tbody>
					</tgroup>
				</table>
			</para>
		</refsect1>
	</refentry>
	<refentry id="function.easter-date">
		<refnamediv>
			<refname>easter_date</refname>
			<refpurpose>
     Get UNIX timestamp for midnight on Easter of a given year
    </refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>int</type><methodname>easter_date</methodname>
					<methodparam><type>int</type><parameter>year</parameter></methodparam>
				</methodsynopsis>
			<para>
     Returns the UNIX timestamp corresponding to midnight on Easter of
     the given year.  If no year is specified, the current year is
     assumed.
    </para>
			<para>
				<emphasis>Warning:</emphasis> This function will generate
     a warning if the year is outside of the range for UNIX
     timestamps (i.e. before 1970 or after 2037).
     <example>
					<title>
						<function>easter_date</function> example</title>
					<programlisting role="php">
echo date ("M-d-Y", easter_date(1999));        /* "Apr-04-1999" */
echo date ("M-d-Y", easter_date(2000));        /* "Apr-23-2000" */
echo date ("M-d-Y", easter_date(2001));        /* "Apr-15-2001" */
      </programlisting>
				</example>
			</para>
			<para>
     The date of Easter Day was defined by the Council of Nicaea in
     AD325 as the Sunday after the first full moon which falls on or
     after the Spring Equinox.  The Equinox is assumed to always fall
     on 21st March, so the calculation reduces to determining the date
     of the full moon and the date of the following Sunday.  The
     algorithm used here was introduced around the year 532 by
     Dionysius Exiguus.  Under the Julian Calendar (for years before
     1753) a simple 19-year cycle is used to track the phases of the
     Moon.  Under the Gregorian Calendar (for years after 1753 -
     devised by Clavius and Lilius, and introduced by Pope Gregory
     XIII in October 1582, and into Britain and its then colonies in
     September 1752) two correction factors are added to make the
     cycle more accurate.
    </para>
			<para>
     (The code is based on a C program by Simon Kershaw,
     &lt;webmaster@ely.anglican.org&gt;)
    </para>
			<para>
     See <function>easter_days</function> for calculating Easter
     before 1970 or after 2037.
    </para>
		</refsect1>
	</refentry>
	<refentry id="function.easter-days">
		<refnamediv>
			<refname>easter_days</refname>
			<refpurpose>
     Get number of days after March 21 on which Easter falls for a
     given year
    </refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>int</type><methodname>easter_days</methodname>
					<methodparam><type>int</type><parameter>year</parameter></methodparam>
				</methodsynopsis>
			<para>
     Returns the number of days after March 21 on which Easter falls
     for a given year.  If no year is specified, the current year is
     assumed.
    </para>
			<para>
     This function can be used instead of
     <function>easter_date</function> to calculate Easter for years
     which fall outside the range of UNIX timestamps (i.e. before 1970
     or after 2037).
     <example>
					<title>
						<function>easter_date</function> example</title>
					<programlisting role="php">
echo easter_days (1999);        /* 14, i.e. April 4   */
echo easter_days (1492);        /* 32, i.e. April 22  */
echo easter_days (1913);        /*  2, i.e. March 23  */
      </programlisting>
				</example>
			</para>
			<para>
     The date of Easter Day was defined by the Council of Nicaea in
     AD325 as the Sunday after the first full moon which falls on or
     after the Spring Equinox.  The Equinox is assumed to always fall
     on 21st March, so the calculation reduces to determining the date
     of the full moon and the date of the following Sunday.  The
     algorithm used here was introduced around the year 532 by
     Dionysius Exiguus.  Under the Julian Calendar (for years before
     1753) a simple 19-year cycle is used to track the phases of the
     Moon.  Under the Gregorian Calendar (for years after 1753 -
     devised by Clavius and Lilius, and introduced by Pope Gregory
     XIII in October 1582, and into Britain and its then colonies in
     September 1752) two correction factors are added to make the
     cycle more accurate.
    </para>
			<para>
     (The code is based on a C program by Simon Kershaw,
     &lt;webmaster@ely.anglican.org&gt;)
    </para>
			<para>
     See also <function>easter_date</function>.
    </para>
		</refsect1>
	</refentry>
	<refentry id="function.unixtojd">
		<refnamediv>
			<refname>unixtojd</refname>
			<refpurpose>Convert UNIX timestamp to Julian Day</refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>int</type><methodname>unixtojd</methodname>
					<methodparam choice="opt"><type>int</type><parameter>
							timestamp
						</parameter></methodparam>
				</methodsynopsis>
			<para>
     Return the Julian Day for a UNIX <parameter>timestamp</parameter>
     (seconds since 1.1.1970), or for the current day if no
     <parameter>timestamp</parameter> is given.
    </para>
			<para>
     See also <function>jdtounix</function>.
    </para>
			<note>
				<para>
      This function is only available in PHP versions after PHP4RC1.
     </para>
			</note>
		</refsect1>
	</refentry>
	<refentry id="function.jdtounix">
		<refnamediv>
			<refname>jdtounix</refname>
			<refpurpose>Convert Julian Day to UNIX timestamp</refpurpose>
		</refnamediv>
		<refsect1>
			<title>Description</title>
				<methodsynopsis>
					<type>int</type><methodname>jdtounix</methodname>
					<methodparam><type>int</type><parameter>jday</parameter></methodparam>
				</methodsynopsis>
			<para>
     This function will return a UNIX timestamp corresponding to the
     Julian Day given in <parameter>jday</parameter> or &false; if
     <parameter>jday</parameter> is not inside the UNIX epoch
     (Gregorian years between 1970 and 2037 or 2440588 &lt;=
     <parameter>jday</parameter> &lt;= 2465342 )
    </para>
			<para>
     See also <function>jdtounix</function>.
    </para>
			<note>
				<para>
      This function is only available in PHP versions after PHP4RC1.
     </para>
			</note>
		</refsect1>
	</refentry>
</reference>
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