1 /* 2 * Copyright (C) 1993-1996 by Andrey A. Chernov, Moscow, Russia. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <stdio.h> 31 #include <stdlib.h> 32 #include <string.h> 33 #include <time.h> 34 35 #include "calendar.h" 36 37 #define PASKHA "paskha" 38 #define PASKHALEN (sizeof(PASKHA) - 1) 39 40 static int paskha (int); 41 42 /* return year day for Orthodox Easter using Gauss formula */ 43 /* (old style result) */ 44 45 static int 46 paskha (R) 47 int R; /*year*/ 48 { 49 int a, b, c, d, e; 50 static int x = 15; 51 static int y = 6; 52 extern int *cumdays; 53 54 a = R % 19; 55 b = R % 4; 56 c = R % 7; 57 d = (19*a + x) % 30; 58 e = (2*b + 4*c + 6*d + y) % 7; 59 return (((cumdays[3] + 1) + 22) + (d + e)); 60 } 61 62 /* return year day for Orthodox Easter depending days */ 63 64 int 65 getpaskha(s, year) 66 char *s; 67 int year; 68 { 69 int offset; 70 extern struct fixs npaskha; 71 72 if (strncasecmp(s, PASKHA, PASKHALEN) == 0) 73 s += PASKHALEN; 74 else if ( npaskha.name != NULL 75 && strncasecmp(s, npaskha.name, npaskha.len) == 0 76 ) 77 s += npaskha.len; 78 else 79 return 0; 80 81 82 /* Paskha+1 or Paskha-2 83 * ^ ^ */ 84 85 switch(*s) { 86 87 case '-': 88 case '+': 89 offset = atoi(s); 90 break; 91 92 default: 93 offset = 0; 94 break; 95 } 96 97 return (paskha(year) + offset + 13/* new style */); 98 } 99