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 } 139 if (otime != NULL) { 140 tmd.tm_hour = strtol(otime, NULL, 10); 141 tmd.tm_min = strtol(otime + 3, NULL, 10); 142 tmd.tm_sec = strtol(otime + 6, NULL, 10); 143 } 144 tt = mktime(&tmd); 145 } 146 147 gmtime_r(&tt, &GMT); 148 days = (GMT.tm_yday + 1) + ((GMT.tm_hour + 149 (GMT.tm_min / 60.0) + (GMT.tm_sec / 3600.0)) / 24.0); 150 for (cnt = EPOCH; cnt < GMT.tm_year; ++cnt) 151 days += isleap(1900 + cnt) ? 366 : 365; 152 today = potm(days) + .5; 153 if (pflag) { 154 (void)printf("%1.0f\n", today); 155 return (0); 156 } 157 (void)printf("The Moon is "); 158 if ((int)today == 100) 159 (void)printf("Full\n"); 160 else if (!(int)today) 161 (void)printf("New\n"); 162 else { 163 tomorrow = potm(days + 1); 164 if ((int)today == 50) 165 (void)printf("%s\n", tomorrow > today ? 166 "at the First Quarter" : "at the Last Quarter"); 167 else { 168 (void)printf("%s ", tomorrow > today ? 169 "Waxing" : "Waning"); 170 if (today > 50) 171 (void)printf("Gibbous (%1.0f%% of Full)\n", 172 today); 173 else if (today < 50) 174 (void)printf("Crescent (%1.0f%% of Full)\n", 175 today); 176 } 177 } 178 179 return 0; 180 } 181 182 /* 183 * potm -- 184 * return phase of the moon 185 */ 186 static double 187 potm(double days) 188 { 189 double N, Msol, Ec, LambdaSol, l, Mm, Ev, Ac, A3, Mmprime; 190 double A4, lprime, V, ldprime, D, Nm; 191 192 N = 360 * days / 365.2422; /* sec 42 #3 */ 193 adj360(&N); 194 Msol = N + EPSILONg - RHOg; /* sec 42 #4 */ 195 adj360(&Msol); 196 Ec = 360 / PI * ECCEN * sin(dtor(Msol)); /* sec 42 #5 */ 197 LambdaSol = N + Ec + EPSILONg; /* sec 42 #6 */ 198 adj360(&LambdaSol); 199 l = 13.1763966 * days + lzero; /* sec 61 #4 */ 200 adj360(&l); 201 Mm = l - (0.1114041 * days) - Pzero; /* sec 61 #5 */ 202 adj360(&Mm); 203 Nm = Nzero - (0.0529539 * days); /* sec 61 #6 */ 204 adj360(&Nm); 205 Ev = 1.2739 * sin(dtor(2*(l - LambdaSol) - Mm)); /* sec 61 #7 */ 206 Ac = 0.1858 * sin(dtor(Msol)); /* sec 61 #8 */ 207 A3 = 0.37 * sin(dtor(Msol)); 208 Mmprime = Mm + Ev - Ac - A3; /* sec 61 #9 */ 209 Ec = 6.2886 * sin(dtor(Mmprime)); /* sec 61 #10 */ 210 A4 = 0.214 * sin(dtor(2 * Mmprime)); /* sec 61 #11 */ 211 lprime = l + Ev + Ec - Ac + A4; /* sec 61 #12 */ 212 V = 0.6583 * sin(dtor(2 * (lprime - LambdaSol))); /* sec 61 #13 */ 213 ldprime = lprime + V; /* sec 61 #14 */ 214 D = ldprime - LambdaSol; /* sec 63 #2 */ 215 return(50 * (1 - cos(dtor(D)))); /* sec 63 #3 */ 216 } 217 218 /* 219 * dtor -- 220 * convert degrees to radians 221 */ 222 static double 223 dtor(double deg) 224 { 225 226 return(deg * PI / 180); 227 } 228 229 /* 230 * adj360 -- 231 * adjust value so 0 <= deg <= 360 232 */ 233 static void 234 adj360(double *deg) 235 { 236 237 for (;;) 238 if (*deg < 0) 239 *deg += 360; 240 else if (*deg > 360) 241 *deg -= 360; 242 else 243 break; 244 } 245 246 static void 247 usage(char *progname) 248 { 249 250 fprintf(stderr, "Usage: %s [-p] [-d yyyy.mm.dd] [-t hh:mm:ss]\n", 251 progname); 252 exit(EX_USAGE); 253 } 254