freebsd-nq/usr.bin/calendar/pom.c
Conrad Meyer fd1efedc79 Add extremely useful calendar(1) application to FreeBSD
It does extremely useful things like execute sendmail and spew dubiously
accurate factoids.

From the feedback, it seems like it is an essential utility in a modern unix
and not at all a useless bikeshed.  How do those Linux people live without it?
Reverts r358561.
2020-03-03 00:20:08 +00:00

279 lines
7.8 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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.
*/
#if 0
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1989, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static const char sccsid[] = "@(#)pom.c 8.1 (Berkeley) 5/31/93";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* 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
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <sysexits.h>
#include <time.h>
#include <unistd.h>
#include "calendar.h"
#ifndef PI
#define PI 3.14159265358979323846
#endif
#define EPOCH 85
#define EPSILONg 279.611371 /* solar ecliptic long at EPOCH */
#define RHOg 282.680403 /* solar ecliptic long of perigee at EPOCH */
#define ECCEN 0.01671542 /* solar orbit eccentricity */
#define lzero 18.251907 /* lunar mean long at EPOCH */
#define Pzero 192.917585 /* lunar mean long of perigee at EPOCH */
#define Nzero 55.204723 /* lunar mean long of node at EPOCH */
#define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
static void adj360(double *);
static double dtor(double);
static double potm(double onday);
static double potm_minute(double onday, int olddir);
void
pom(int year, double utcoffset, int *fms, int *nms)
{
double ffms[MAXMOONS];
double fnms[MAXMOONS];
int i, j;
fpom(year, utcoffset, ffms, fnms);
j = 0;
for (i = 0; ffms[i] != 0; i++)
fms[j++] = round(ffms[i]);
fms[i] = -1;
for (i = 0; fnms[i] != 0; i++)
nms[i] = round(fnms[i]);
nms[i] = -1;
}
void
fpom(int year, double utcoffset, double *ffms, double *fnms)
{
time_t tt;
struct tm GMT, tmd_today, tmd_tomorrow;
double days_today, days_tomorrow, today, tomorrow;
int cnt, d;
int yeardays;
int olddir, newdir;
double *pfnms, *pffms, t;
pfnms = fnms;
pffms = ffms;
/*
* We take the phase of the moon one second before and one second
* after midnight.
*/
memset(&tmd_today, 0, sizeof(tmd_today));
tmd_today.tm_year = year - 1900;
tmd_today.tm_mon = 0;
tmd_today.tm_mday = -1; /* 31 December */
tmd_today.tm_hour = 23;
tmd_today.tm_min = 59;
tmd_today.tm_sec = 59;
memset(&tmd_tomorrow, 0, sizeof(tmd_tomorrow));
tmd_tomorrow.tm_year = year - 1900;
tmd_tomorrow.tm_mon = 0;
tmd_tomorrow.tm_mday = 0; /* 01 January */
tmd_tomorrow.tm_hour = 0;
tmd_tomorrow.tm_min = 0;
tmd_tomorrow.tm_sec = 1;
tt = mktime(&tmd_today);
gmtime_r(&tt, &GMT);
yeardays = 0;
for (cnt = EPOCH; cnt < GMT.tm_year; ++cnt)
yeardays += isleap(1900 + cnt) ? DAYSPERLEAPYEAR : DAYSPERYEAR;
days_today = (GMT.tm_yday + 1) + ((GMT.tm_hour +
(GMT.tm_min / FSECSPERMINUTE) + (GMT.tm_sec / FSECSPERHOUR)) /
FHOURSPERDAY);
days_today += yeardays;
tt = mktime(&tmd_tomorrow);
gmtime_r(&tt, &GMT);
yeardays = 0;
for (cnt = EPOCH; cnt < GMT.tm_year; ++cnt)
yeardays += isleap(1900 + cnt) ? DAYSPERLEAPYEAR : DAYSPERYEAR;
days_tomorrow = (GMT.tm_yday + 1) + ((GMT.tm_hour +
(GMT.tm_min / FSECSPERMINUTE) + (GMT.tm_sec / FSECSPERHOUR)) /
FHOURSPERDAY);
days_tomorrow += yeardays;
today = potm(days_today); /* 30 December 23:59:59 */
tomorrow = potm(days_tomorrow); /* 31 December 00:00:01 */
olddir = today > tomorrow ? -1 : +1;
yeardays = 1 + (isleap(year) ? DAYSPERLEAPYEAR : DAYSPERYEAR); /* reuse */
for (d = 0; d <= yeardays; d++) {
today = potm(days_today);
tomorrow = potm(days_tomorrow);
newdir = today > tomorrow ? -1 : +1;
if (olddir != newdir) {
t = potm_minute(days_today - 1, olddir) +
utcoffset / FHOURSPERDAY;
if (olddir == -1 && newdir == +1) {
*pfnms = d - 1 + t;
pfnms++;
} else if (olddir == +1 && newdir == -1) {
*pffms = d - 1 + t;
pffms++;
}
}
olddir = newdir;
days_today++;
days_tomorrow++;
}
*pffms = -1;
*pfnms = -1;
}
static double
potm_minute(double onday, int olddir) {
double period = FSECSPERDAY / 2.0;
double p1, p2;
double before, after;
int newdir;
// printf("---> days:%g olddir:%d\n", days, olddir);
p1 = onday + (period / SECSPERDAY);
period /= 2;
while (period > 30) { /* half a minute */
// printf("period:%g - p1:%g - ", period, p1);
p2 = p1 + (2.0 / SECSPERDAY);
before = potm(p1);
after = potm(p2);
// printf("before:%10.10g - after:%10.10g\n", before, after);
newdir = before < after ? -1 : +1;
if (olddir != newdir)
p1 += (period / SECSPERDAY);
else
p1 -= (period / SECSPERDAY);
period /= 2;
// printf("newdir:%d - p1:%10.10f - period:%g\n",
// newdir, p1, period);
}
p1 -= floor(p1);
//exit(0);
return (p1);
}
/*
* potm --
* return phase of the moon, as a percentage [0 ... 100]
*/
static double
potm(double onday)
{
double N, Msol, Ec, LambdaSol, l, Mm, Ev, Ac, A3, Mmprime;
double A4, lprime, V, ldprime, D, Nm;
N = 360 * onday / 365.2422; /* sec 42 #3 */
adj360(&N);
Msol = N + EPSILONg - RHOg; /* sec 42 #4 */
adj360(&Msol);
Ec = 360 / PI * ECCEN * sin(dtor(Msol)); /* sec 42 #5 */
LambdaSol = N + Ec + EPSILONg; /* sec 42 #6 */
adj360(&LambdaSol);
l = 13.1763966 * onday + lzero; /* sec 61 #4 */
adj360(&l);
Mm = l - (0.1114041 * onday) - Pzero; /* sec 61 #5 */
adj360(&Mm);
Nm = Nzero - (0.0529539 * onday); /* sec 61 #6 */
adj360(&Nm);
Ev = 1.2739 * sin(dtor(2*(l - LambdaSol) - Mm)); /* sec 61 #7 */
Ac = 0.1858 * sin(dtor(Msol)); /* sec 61 #8 */
A3 = 0.37 * sin(dtor(Msol));
Mmprime = Mm + Ev - Ac - A3; /* sec 61 #9 */
Ec = 6.2886 * sin(dtor(Mmprime)); /* sec 61 #10 */
A4 = 0.214 * sin(dtor(2 * Mmprime)); /* sec 61 #11 */
lprime = l + Ev + Ec - Ac + A4; /* sec 61 #12 */
V = 0.6583 * sin(dtor(2 * (lprime - LambdaSol))); /* sec 61 #13 */
ldprime = lprime + V; /* sec 61 #14 */
D = ldprime - LambdaSol; /* sec 63 #2 */
return(50 * (1 - cos(dtor(D)))); /* sec 63 #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;
}