php-src/ext/calendar/easter.c

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/*
+----------------------------------------------------------------------+
| PHP version 4.0 |
+----------------------------------------------------------------------+
| Copyright (c) 1997, 1998, 1999, 2000 The PHP Group |
+----------------------------------------------------------------------+
| This source file is subject to version 2.01 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_01.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. |
+----------------------------------------------------------------------+
| Authors: Shane Caraveo <shane@caraveo.com> |
| Colin Viebrock <cmv@easydns.com> |
| Hartmut Holzgraefe <hartmut@six.de> |
+----------------------------------------------------------------------+
*/
/* $Id: */
#include "php.h"
#include "php_calendar.h"
#include "sdncal.h"
#include <time.h>
static void _cal_easter(INTERNAL_FUNCTION_PARAMETERS, int gm)
{
/* based on code by Simon Kershaw, <webmaster@ely.anglican.org> */
pval *year_arg;
struct tm *ta, te;
time_t the_time;
long year, golden, solar, lunar, pfm, dom, tmp, easter;
switch(ARG_COUNT(ht)) {
case 0:
the_time = time(NULL);
ta = localtime(&the_time);
year = ta->tm_year + 1900;
break;
case 1:
if (getParameters(ht, 1, &year_arg) == FAILURE) {
WRONG_PARAM_COUNT;
}
convert_to_long(year_arg);
year = year_arg->value.lval;
break;
default:
WRONG_PARAM_COUNT;
}
if (gm && (year<1970 || year>2037)) { /* out of range for timestamps */
php3_error(E_WARNING, "easter_date() is only valid for years between 1970 and 2037 inclusive");
RETURN_FALSE;
}
golden = (year % 19) + 1; /* the Golden number */
if ( year <= 1752 ) { /* JULIAN CALENDAR */
dom = (year + (year/4) + 5) % 7; /* the "Dominical number" - finding a Sunday */
if (dom < 0) {
dom += 7;
}
pfm = (3 - (11*golden) - 7) % 30; /* uncorrected date of the Paschal full moon */
if (pfm < 0) {
pfm += 30;
}
} else { /* GREGORIAN CALENDAR */
dom = (year + (year/4) - (year/100) + (year/400)) % 7; /* the "Domincal number" */
if (dom < 0) {
dom += 7;
}
solar = (year-1600)/100 - (year-1600)/400; /* the solar and lunar corrections */
lunar = (((year-1400) / 100) * 8) / 25;
pfm = (3 - (11*golden) + solar - lunar) % 30; /* uncorrected date of the Paschal full moon */
if (pfm < 0) {
pfm += 30;
}
}
if ((pfm == 29) || (pfm == 28 && golden > 11)) { /* corrected date of the Paschal full moon */
pfm--; /* - days after 21st March */
}
tmp = (4-pfm-dom) % 7;
if (tmp < 0) {
tmp += 7;
}
easter = pfm + tmp + 1; /* Easter as the number of days after 21st March */
if (gm) { /* return a timestamp */
te.tm_isdst = -1;
te.tm_year = year-1900;
te.tm_sec = 0;
te.tm_min = 0;
te.tm_hour = 0;
if (easter < 11) {
te.tm_mon = 2; /* March */
te.tm_mday = easter+21;
} else {
te.tm_mon = 3; /* April */
te.tm_mday = easter-10;
}
return_value->value.lval = mktime(&te);
} else { /* return the days after March 21 */
return_value->value.lval = easter;
}
return_value->type = IS_LONG;
}
/* {{{ proto int easter_date([int year])
Return the timestamp of midnight on Easter of a given year (defaults to current year) */
PHP_FUNCTION(easter_date)
{
_cal_easter(INTERNAL_FUNCTION_PARAM_PASSTHRU, 1);
}
/* }}} */
/* {{{ proto int easter_days([int year])
Return the number of days after March 21 that Easter falls on for a given year (defaults to current year) */
PHP_FUNCTION(easter_days)
{
_cal_easter(INTERNAL_FUNCTION_PARAM_PASSTHRU, 0);
}
/* }}} */
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
*/