1 /* 2 * Copyright (c) 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software posted to USENET. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #if 0 33 #ifndef lint 34 static const char copyright[] = 35 "@(#) Copyright (c) 1989, 1993\n\ 36 The Regents of the University of California. All rights reserved.\n"; 37 #endif /* not lint */ 38 39 #ifndef lint 40 static const char sccsid[] = "@(#)pom.c 8.1 (Berkeley) 5/31/93"; 41 #endif /* not lint */ 42 #endif 43 #include <sys/cdefs.h> 44 __FBSDID("$FreeBSD$"); 45 46 /* 47 * Phase of the Moon. Calculates the current phase of the moon. 48 * Based on routines from `Practical Astronomy with Your Calculator', 49 * by Duffett-Smith. Comments give the section from the book that 50 * particular piece of code was adapted from. 51 * 52 * -- Keith E. Brandt VIII 1984 53 * 54 */ 55 56 #include <sys/capsicum.h> 57 #include <capsicum_helpers.h> 58 59 #include <err.h> 60 #include <errno.h> 61 #include <stdio.h> 62 #include <stdlib.h> 63 #include <math.h> 64 #include <string.h> 65 #include <sysexits.h> 66 #include <time.h> 67 #include <unistd.h> 68 69 #ifndef PI 70 #define PI 3.14159265358979323846 71 #endif 72 #define EPOCH 85 73 #define EPSILONg 279.611371 /* solar ecliptic long at EPOCH */ 74 #define RHOg 282.680403 /* solar ecliptic long of perigee at EPOCH */ 75 #define ECCEN 0.01671542 /* solar orbit eccentricity */ 76 #define lzero 18.251907 /* lunar mean long at EPOCH */ 77 #define Pzero 192.917585 /* lunar mean long of perigee at EPOCH */ 78 #define Nzero 55.204723 /* lunar mean long of node at EPOCH */ 79 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0) 80 81 static void adj360(double *); 82 static double dtor(double); 83 static double potm(double); 84 static void usage(char *progname); 85 86 int 87 main(int argc, char **argv) 88 { 89 time_t tt; 90 struct tm GMT, tmd; 91 double days, today, tomorrow; 92 int ch, cnt, pflag = 0; 93 char *odate = NULL, *otime = NULL; 94 char *progname = argv[0]; 95 96 if (caph_limit_stdio() < 0) 97 err(1, "unable to limit capabitilities for stdio"); 98 99 caph_cache_catpages(); 100 if (caph_enter() < 0) 101 err(1, "unable to enter capability mode"); 102 103 while ((ch = getopt(argc, argv, "d:pt:")) != -1) 104 switch (ch) { 105 case 'd': 106 odate = optarg; 107 break; 108 case 'p': 109 pflag = 1; 110 break; 111 case 't': 112 otime = optarg; 113 break; 114 default: 115 usage(progname); 116 } 117 118 argc -= optind; 119 argv += optind; 120 121 if (argc) 122 usage(progname); 123 124 /* Adjust based on users preferences */ 125 time(&tt); 126 if (otime != NULL || odate != NULL) { 127 /* Save today in case -d isn't specified */ 128 localtime_r(&tt, &tmd); 129 130 if (odate != NULL) { 131 tmd.tm_year = strtol(odate, NULL, 10) - 1900; 132 tmd.tm_mon = strtol(odate + 5, NULL, 10) - 1; 133 tmd.tm_mday = strtol(odate + 8, NULL, 10); 134 /* Use midnight as the middle of the night */ 135 tmd.tm_hour = 0; 136 tmd.tm_min = 0; 137 tmd.tm_sec = 0; 138 tmd.tm_isdst = -1; 139 } 140 if (otime != NULL) { 141 tmd.tm_hour = strtol(otime, NULL, 10); 142 tmd.tm_min = strtol(otime + 3, NULL, 10); 143 tmd.tm_sec = strtol(otime + 6, NULL, 10); 144 tmd.tm_isdst = -1; 145 } 146 tt = mktime(&tmd); 147 } 148 149 gmtime_r(&tt, &GMT); 150 days = (GMT.tm_yday + 1) + ((GMT.tm_hour + 151 (GMT.tm_min / 60.0) + (GMT.tm_sec / 3600.0)) / 24.0); 152 for (cnt = EPOCH; cnt < GMT.tm_year; ++cnt) 153 days += isleap(1900 + cnt) ? 366 : 365; 154 today = potm(days); 155 if (pflag) { 156 (void)printf("%1.0f\n", today); 157 return (0); 158 } 159 (void)printf("The Moon is "); 160 if (today >= 99.5) 161 (void)printf("Full\n"); 162 else if (today < 0.5) 163 (void)printf("New\n"); 164 else { 165 tomorrow = potm(days + 1); 166 if (today >= 49.5 && today < 50.5) 167 (void)printf("%s\n", tomorrow > today ? 168 "at the First Quarter" : "at the Last Quarter"); 169 else { 170 (void)printf("%s ", tomorrow > today ? 171 "Waxing" : "Waning"); 172 if (today > 50) 173 (void)printf("Gibbous (%1.0f%% of Full)\n", 174 today); 175 else if (today < 50) 176 (void)printf("Crescent (%1.0f%% of Full)\n", 177 today); 178 } 179 } 180 181 return 0; 182 } 183 184 /* 185 * potm -- 186 * return phase of the moon 187 */ 188 static double 189 potm(double days) 190 { 191 double N, Msol, Ec, LambdaSol, l, Mm, Ev, Ac, A3, Mmprime; 192 double A4, lprime, V, ldprime, D, Nm; 193 194 N = 360 * days / 365.2422; /* sec 42 #3 */ 195 adj360(&N); 196 Msol = N + EPSILONg - RHOg; /* sec 42 #4 */ 197 adj360(&Msol); 198 Ec = 360 / PI * ECCEN * sin(dtor(Msol)); /* sec 42 #5 */ 199 LambdaSol = N + Ec + EPSILONg; /* sec 42 #6 */ 200 adj360(&LambdaSol); 201 l = 13.1763966 * days + lzero; /* sec 61 #4 */ 202 adj360(&l); 203 Mm = l - (0.1114041 * days) - Pzero; /* sec 61 #5 */ 204 adj360(&Mm); 205 Nm = Nzero - (0.0529539 * days); /* sec 61 #6 */ 206 adj360(&Nm); 207 Ev = 1.2739 * sin(dtor(2*(l - LambdaSol) - Mm)); /* sec 61 #7 */ 208 Ac = 0.1858 * sin(dtor(Msol)); /* sec 61 #8 */ 209 A3 = 0.37 * sin(dtor(Msol)); 210 Mmprime = Mm + Ev - Ac - A3; /* sec 61 #9 */ 211 Ec = 6.2886 * sin(dtor(Mmprime)); /* sec 61 #10 */ 212 A4 = 0.214 * sin(dtor(2 * Mmprime)); /* sec 61 #11 */ 213 lprime = l + Ev + Ec - Ac + A4; /* sec 61 #12 */ 214 V = 0.6583 * sin(dtor(2 * (lprime - LambdaSol))); /* sec 61 #13 */ 215 ldprime = lprime + V; /* sec 61 #14 */ 216 D = ldprime - LambdaSol; /* sec 63 #2 */ 217 return(50 * (1 - cos(dtor(D)))); /* sec 63 #3 */ 218 } 219 220 /* 221 * dtor -- 222 * convert degrees to radians 223 */ 224 static double 225 dtor(double deg) 226 { 227 228 return(deg * PI / 180); 229 } 230 231 /* 232 * adj360 -- 233 * adjust value so 0 <= deg <= 360 234 */ 235 static void 236 adj360(double *deg) 237 { 238 239 for (;;) 240 if (*deg < 0) 241 *deg += 360; 242 else if (*deg > 360) 243 *deg -= 360; 244 else 245 break; 246 } 247 248 static void 249 usage(char *progname) 250 { 251 252 fprintf(stderr, "Usage: %s [-p] [-d yyyy.mm.dd] [-t hh:mm:ss]\n", 253 progname); 254 exit(EX_USAGE); 255 } 256