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Diffstat (limited to 'usr.bin/calendar/pom.c')
-rw-r--r-- | usr.bin/calendar/pom.c | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/usr.bin/calendar/pom.c b/usr.bin/calendar/pom.c new file mode 100644 index 0000000..89d06a2 --- /dev/null +++ b/usr.bin/calendar/pom.c @@ -0,0 +1,276 @@ +/* + * 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. + * 4. 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; +} |