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 <stdio.h> 28 #include <stdlib.h> 29 #include <string.h> 30 #include <time.h> 31 32 #include "calendar.h" 33 34 #define PASKHA "paskha" 35 #define PASKHALEN (sizeof(PASKHA) - 1) 36 37 /* return year day for Orthodox Easter using Gauss formula */ 38 /* (old style result) */ 39 40 static int 41 paskha (R) 42 int R; /*year*/ 43 { 44 int a, b, c, d, e; 45 static int x = 15; 46 static int y = 6; 47 extern int *cumdays; 48 49 a = R % 19; 50 b = R % 4; 51 c = R % 7; 52 d = (19*a + x) % 30; 53 e = (2*b + 4*c + 6*d + y) % 7; 54 return (((cumdays[3] + 1) + 22) + (d + e)); 55 } 56 57 /* return year day for Orthodox Easter depending days */ 58 59 int 60 getpaskha(s, year) 61 char *s; 62 int year; 63 { 64 int offset; 65 extern struct fixs npaskha; 66 67 if (strncasecmp(s, PASKHA, PASKHALEN) == 0) 68 s += PASKHALEN; 69 else if ( npaskha.name != NULL 70 && strncasecmp(s, npaskha.name, npaskha.len) == 0 71 ) 72 s += npaskha.len; 73 else 74 return 0; 75 76 77 /* Paskha+1 or Paskha-2 78 * ^ ^ */ 79 80 switch(*s) { 81 82 case '-': 83 case '+': 84 offset = atoi(s); 85 break; 86 87 default: 88 offset = 0; 89 break; 90 } 91 92 return (paskha(year) + offset + 13/* new style */); 93 } 94