paskha.c revision 181322
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 181322 2008-08-05 08:11:54Z edwin $"); 2987235Smarkm 3015737Sache#include <stdio.h> 3115714Sache#include <stdlib.h> 3215714Sache#include <string.h> 3315737Sache#include <time.h> 3415714Sache 3515720Sache#include "calendar.h" 3615720Sache 37181322Sedwin#define PASKHA "paskha" 38181322Sedwin#define PASKHALEN (sizeof(PASKHA) - 1) 3915714Sache 40181322Sedwinstatic 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; 55181322Sedwin d = (19 * a + x) % 30; 56181322Sedwin 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) 68181322Sedwin s += PASKHALEN; 69181322Sedwin else if (npaskha.name != NULL 70181322Sedwin && strncasecmp(s, npaskha.name, npaskha.len) == 0) 71181322Sedwin s += npaskha.len; 7215714Sache else 73181322Sedwin return 0; 7415714Sache 7515714Sache /* Paskha+1 or Paskha-2 7615714Sache * ^ ^ */ 7715714Sache 78181322Sedwin switch (*s) { 7915714Sache 8015714Sache case '-': 8115714Sache case '+': 82181322Sedwin offset = atoi(s); 83181322Sedwin break; 8415714Sache 8515714Sache default: 86181322Sedwin offset = 0; 87181322Sedwin break; 8815714Sache } 89181322Sedwin 90181322Sedwin return (paskha(year) + offset + 13 /* new style */); 9115714Sache} 92