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 29 __FBSDID("$FreeBSD$"); 30 31 #include <stdio.h> 32 #include <stdlib.h> 33 #include <string.h> 34 #include <time.h> 35 36 #include "calendar.h" 37 38 #define PASKHA "paskha" 39 #define PASKHALEN (sizeof(PASKHA) - 1) 40 41 static int paskha (int); 42 43 /* return year day for Orthodox Easter using Gauss formula */ 44 /* (old style result) */ 45 46 static int 47 paskha (R) 48 int R; /*year*/ 49 { 50 int a, b, c, d, e; 51 static int x = 15; 52 static int y = 6; 53 extern int *cumdays; 54 55 a = R % 19; 56 b = R % 4; 57 c = R % 7; 58 d = (19*a + x) % 30; 59 e = (2*b + 4*c + 6*d + y) % 7; 60 return (((cumdays[3] + 1) + 22) + (d + e)); 61 } 62 63 /* return year day for Orthodox Easter depending days */ 64 65 int 66 getpaskha(s, year) 67 char *s; 68 int year; 69 { 70 int offset; 71 extern struct fixs npaskha; 72 73 if (strncasecmp(s, PASKHA, PASKHALEN) == 0) 74 s += PASKHALEN; 75 else if ( npaskha.name != NULL 76 && strncasecmp(s, npaskha.name, npaskha.len) == 0 77 ) 78 s += npaskha.len; 79 else 80 return 0; 81 82 83 /* Paskha+1 or Paskha-2 84 * ^ ^ */ 85 86 switch(*s) { 87 88 case '-': 89 case '+': 90 offset = atoi(s); 91 break; 92 93 default: 94 offset = 0; 95 break; 96 } 97 98 return (paskha(year) + offset + 13/* new style */); 99 } 100