278 lines
7.6 KiB
C
278 lines
7.6 KiB
C
/* $NetBSD: pom.c,v 1.19 2009/08/12 08:23:20 dholland Exp $ */
|
|
|
|
/*
|
|
* Copyright (c) 1989, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This code is derived from software posted to USENET.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
#ifndef lint
|
|
__COPYRIGHT("@(#) Copyright (c) 1989, 1993\
|
|
The Regents of the University of California. All rights reserved.");
|
|
#endif /* not lint */
|
|
|
|
#ifndef lint
|
|
#if 0
|
|
static char sccsid[] = "@(#)pom.c 8.1 (Berkeley) 5/31/93";
|
|
#else
|
|
__RCSID("$NetBSD: pom.c,v 1.19 2009/08/12 08:23:20 dholland Exp $");
|
|
#endif
|
|
#endif /* not lint */
|
|
|
|
/*
|
|
* Phase of the Moon. Calculates the current phase of the moon.
|
|
* Based on routines from `Practical Astronomy with Your Calculator',
|
|
* by Duffett-Smith. Comments give the section from the book that
|
|
* particular piece of code was adapted from.
|
|
*
|
|
* -- Keith E. Brandt VIII 1984
|
|
*
|
|
* Updated to the Third Edition of Duffett-Smith's book, Paul Janzen, IX 1998
|
|
*
|
|
*/
|
|
|
|
#include <ctype.h>
|
|
#include <err.h>
|
|
#include <math.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <stdlib.h>
|
|
#include <time.h>
|
|
#include <unistd.h>
|
|
|
|
#ifndef PI
|
|
#define PI 3.14159265358979323846
|
|
#endif
|
|
|
|
/*
|
|
* The EPOCH in the third edition of the book is 1990 Jan 0.0 TDT.
|
|
* In this program, we do not bother to correct for the differences
|
|
* between UTC (as shown by the UNIX clock) and TDT. (TDT = TAI + 32.184s;
|
|
* TAI-UTC = 32s in Jan 1999.)
|
|
*/
|
|
#define EPOCH_MINUS_1970 (20 * 365 + 5 - 1) /* 20 years, 5 leaps, back 1 day to Jan 0 */
|
|
#define EPSILONg 279.403303 /* solar ecliptic long at EPOCH */
|
|
#define RHOg 282.768422 /* solar ecliptic long of perigee at EPOCH */
|
|
#define ECCEN 0.016713 /* solar orbit eccentricity */
|
|
#define lzero 318.351648 /* lunar mean long at EPOCH */
|
|
#define Pzero 36.340410 /* lunar mean long of perigee at EPOCH */
|
|
#define Nzero 318.510107 /* lunar mean long of node at EPOCH */
|
|
|
|
int main(int, char *[]);
|
|
static void adj360(double *);
|
|
static double dtor(double);
|
|
static double potm(double);
|
|
static time_t parsetime(char *);
|
|
static void badformat(void) __dead;
|
|
|
|
int
|
|
main(int argc, char *argv[])
|
|
{
|
|
time_t tmpt, now;
|
|
double days, today, tomorrow;
|
|
char buf[1024];
|
|
|
|
if (time(&now) == (time_t)-1)
|
|
err(1, "time");
|
|
if (argc > 1) {
|
|
tmpt = parsetime(argv[1]);
|
|
strftime(buf, sizeof(buf), "%a %Y %b %e %H:%M:%S (%Z)",
|
|
localtime(&tmpt));
|
|
printf("%s: ", buf);
|
|
} else {
|
|
tmpt = now;
|
|
}
|
|
days = (tmpt - EPOCH_MINUS_1970 * 86400) / 86400.0;
|
|
today = potm(days) + .5;
|
|
if (tmpt < now)
|
|
(void)printf("The Moon was ");
|
|
else if (tmpt == now)
|
|
(void)printf("The Moon is ");
|
|
else
|
|
(void)printf("The Moon will be ");
|
|
if ((int)today == 100)
|
|
(void)printf("Full\n");
|
|
else if (!(int)today)
|
|
(void)printf("New\n");
|
|
else {
|
|
tomorrow = potm(days + 1);
|
|
if ((int)today == 50)
|
|
(void)printf("%s\n", tomorrow > today ?
|
|
"at the First Quarter" : "at the Last Quarter");
|
|
/* today is 0.5 too big, but it doesn't matter here
|
|
* since the phase is changing fast enough
|
|
*/
|
|
else {
|
|
today -= 0.5; /* Now it might matter */
|
|
(void)printf("%s ", tomorrow > today ?
|
|
"Waxing" : "Waning");
|
|
if (today > 50)
|
|
(void)printf("Gibbous (%1.0f%% of Full)\n",
|
|
today);
|
|
else if (today < 50)
|
|
(void)printf("Crescent (%1.0f%% of Full)\n",
|
|
today);
|
|
}
|
|
}
|
|
|
|
return EXIT_SUCCESS;
|
|
}
|
|
|
|
/*
|
|
* potm --
|
|
* return phase of the moon
|
|
*/
|
|
static double
|
|
potm(double days)
|
|
{
|
|
double N, Msol, Ec, LambdaSol, l, Mm, Ev, Ac, A3, Mmprime;
|
|
double A4, lprime, V, ldprime, D, Nm;
|
|
|
|
N = 360 * days / 365.242191; /* sec 46 #3 */
|
|
adj360(&N);
|
|
Msol = N + EPSILONg - RHOg; /* sec 46 #4 */
|
|
adj360(&Msol);
|
|
Ec = 360 / PI * ECCEN * sin(dtor(Msol)); /* sec 46 #5 */
|
|
LambdaSol = N + Ec + EPSILONg; /* sec 46 #6 */
|
|
adj360(&LambdaSol);
|
|
l = 13.1763966 * days + lzero; /* sec 65 #4 */
|
|
adj360(&l);
|
|
Mm = l - (0.1114041 * days) - Pzero; /* sec 65 #5 */
|
|
adj360(&Mm);
|
|
Nm = Nzero - (0.0529539 * days); /* sec 65 #6 */
|
|
adj360(&Nm);
|
|
Ev = 1.2739 * sin(dtor(2*(l - LambdaSol) - Mm)); /* sec 65 #7 */
|
|
Ac = 0.1858 * sin(dtor(Msol)); /* sec 65 #8 */
|
|
A3 = 0.37 * sin(dtor(Msol));
|
|
Mmprime = Mm + Ev - Ac - A3; /* sec 65 #9 */
|
|
Ec = 6.2886 * sin(dtor(Mmprime)); /* sec 65 #10 */
|
|
A4 = 0.214 * sin(dtor(2 * Mmprime)); /* sec 65 #11 */
|
|
lprime = l + Ev + Ec - Ac + A4; /* sec 65 #12 */
|
|
V = 0.6583 * sin(dtor(2 * (lprime - LambdaSol))); /* sec 65 #13 */
|
|
ldprime = lprime + V; /* sec 65 #14 */
|
|
D = ldprime - LambdaSol; /* sec 67 #2 */
|
|
return(50.0 * (1 - cos(dtor(D)))); /* sec 67 #3 */
|
|
}
|
|
|
|
/*
|
|
* dtor --
|
|
* convert degrees to radians
|
|
*/
|
|
static double
|
|
dtor(double deg)
|
|
{
|
|
return(deg * PI / 180);
|
|
}
|
|
|
|
/*
|
|
* adj360 --
|
|
* adjust value so 0 <= deg <= 360
|
|
*/
|
|
static void
|
|
adj360(double *deg)
|
|
{
|
|
for (;;)
|
|
if (*deg < 0)
|
|
*deg += 360;
|
|
else if (*deg > 360)
|
|
*deg -= 360;
|
|
else
|
|
break;
|
|
}
|
|
|
|
#define ATOI2(ar) ((ar)[0] - '0') * 10 + ((ar)[1] - '0'); (ar) += 2;
|
|
static time_t
|
|
parsetime(char *p)
|
|
{
|
|
struct tm *lt;
|
|
int bigyear;
|
|
int yearset = 0;
|
|
time_t tval;
|
|
char *t;
|
|
|
|
for (t = p; *t; ++t) {
|
|
if (isdigit((unsigned char) *t))
|
|
continue;
|
|
badformat();
|
|
}
|
|
|
|
tval = time(NULL);
|
|
lt = localtime(&tval);
|
|
lt->tm_sec = 0;
|
|
lt->tm_min = 0;
|
|
|
|
switch (strlen(p)) {
|
|
case 10: /* yyyy */
|
|
bigyear = ATOI2(p);
|
|
lt->tm_year = bigyear * 100 - 1900;
|
|
yearset = 1;
|
|
/* FALLTHROUGH */
|
|
case 8: /* yy */
|
|
if (yearset) {
|
|
lt->tm_year += ATOI2(p);
|
|
} else {
|
|
lt->tm_year = ATOI2(p);
|
|
if (lt->tm_year < 69) /* hack for 2000 */
|
|
lt->tm_year += 100;
|
|
}
|
|
/* FALLTHROUGH */
|
|
case 6: /* mm */
|
|
lt->tm_mon = ATOI2(p);
|
|
if ((lt->tm_mon > 12) || !lt->tm_mon)
|
|
badformat();
|
|
--lt->tm_mon; /* time struct is 0 - 11 */
|
|
/* FALLTHROUGH */
|
|
case 4: /* dd */
|
|
lt->tm_mday = ATOI2(p);
|
|
if ((lt->tm_mday > 31) || !lt->tm_mday)
|
|
badformat();
|
|
/* FALLTHROUGH */
|
|
case 2: /* HH */
|
|
lt->tm_hour = ATOI2(p);
|
|
if (lt->tm_hour > 23)
|
|
badformat();
|
|
break;
|
|
default:
|
|
badformat();
|
|
}
|
|
/* The calling code needs a valid tm_ydays and this is the easiest
|
|
* way to get one */
|
|
if ((tval = mktime(lt)) == -1)
|
|
errx(1, "specified date is outside allowed range");
|
|
return (tval);
|
|
}
|
|
|
|
static void
|
|
badformat(void)
|
|
{
|
|
warnx("illegal time format");
|
|
(void)fprintf(stderr, "usage: pom [[[[[cc]yy]mm]dd]HH]\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|