paskha.c revision 169343
115714Sache/* 215714Sache * Copyright (C) 1993-1996 by Andrey A. Chernov, Moscow, Russia. 315714Sache * All rights reserved. 415714Sache * 515714Sache * Redistribution and use in source and binary forms, with or without 615714Sache * modification, are permitted provided that the following conditions 715714Sache * are met: 815714Sache * 1. Redistributions of source code must retain the above copyright 915714Sache * notice, this list of conditions and the following disclaimer. 1015714Sache * 2. Redistributions in binary form must reproduce the above copyright 1115714Sache * notice, this list of conditions and the following disclaimer in the 1215714Sache * documentation and/or other materials provided with the distribution. 1315714Sache * 1415714Sache * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND 1515714Sache * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1615714Sache * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1715714Sache * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 1815714Sache * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 1915714Sache * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2015714Sache * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2115714Sache * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2215714Sache * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2315714Sache * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2415714Sache * SUCH DAMAGE. 2515714Sache */ 2615714Sache 2787235Smarkm#include <sys/cdefs.h> 2887235Smarkm__FBSDID("$FreeBSD: head/usr.bin/calendar/paskha.c 169343 2007-05-07 11:18:30Z dwmalone $"); 2987235Smarkm 3015737Sache#include <stdio.h> 3115714Sache#include <stdlib.h> 3215714Sache#include <string.h> 3315737Sache#include <time.h> 3415714Sache 3515720Sache#include "calendar.h" 3615720Sache 3715714Sache#define PASKHA "paskha" 3815714Sache#define PASKHALEN (sizeof(PASKHA) - 1) 3915714Sache 4087235Smarkmstatic int paskha (int); 4187235Smarkm 4215714Sache/* return year day for Orthodox Easter using Gauss formula */ 4315714Sache/* (old style result) */ 4415714Sache 4515714Sachestatic int 46169343Sdwmalonepaskha(int R) /*year*/ 4715714Sache{ 4815714Sache int a, b, c, d, e; 4915714Sache static int x = 15; 5015714Sache static int y = 6; 5115714Sache 5215714Sache a = R % 19; 5315714Sache b = R % 4; 5415714Sache c = R % 7; 5515714Sache d = (19*a + x) % 30; 5615714Sache e = (2*b + 4*c + 6*d + y) % 7; 5715723Sache return (((cumdays[3] + 1) + 22) + (d + e)); 5815714Sache} 5915714Sache 6015714Sache/* return year day for Orthodox Easter depending days */ 6115714Sache 6215714Sacheint 63169343Sdwmalonegetpaskha(char *s, int year) 6415714Sache{ 6515714Sache int offset; 6615714Sache 6715714Sache if (strncasecmp(s, PASKHA, PASKHALEN) == 0) 6815714Sache s += PASKHALEN; 6915720Sache else if ( npaskha.name != NULL 7015720Sache && strncasecmp(s, npaskha.name, npaskha.len) == 0 7115720Sache ) 7215720Sache s += npaskha.len; 7315714Sache else 7415714Sache return 0; 7515714Sache 7615714Sache 7715714Sache /* Paskha+1 or Paskha-2 7815714Sache * ^ ^ */ 7915714Sache 8015714Sache switch(*s) { 8115714Sache 8215714Sache case '-': 8315714Sache case '+': 8415714Sache offset = atoi(s); 8515714Sache break; 8615714Sache 8715714Sache default: 8815714Sache offset = 0; 8915714Sache break; 9015714Sache } 9115714Sache 9215714Sache return (paskha(year) + offset + 13/* new style */); 9315714Sache} 94