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Diffstat (limited to 'libkholidays/lunarphase.cpp')
| -rw-r--r-- | libkholidays/lunarphase.cpp | 291 |
1 files changed, 291 insertions, 0 deletions
diff --git a/libkholidays/lunarphase.cpp b/libkholidays/lunarphase.cpp new file mode 100644 index 00000000..56f5fbe5 --- /dev/null +++ b/libkholidays/lunarphase.cpp @@ -0,0 +1,291 @@ +/* + This file is part of libkholidays. + Copyright (c) 2004 Allen Winter <winter@kde.org> + + Copyright (c) 1989, 1993 + The Regents of the University of California. All rights reserved. + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + + In addition, as a special exception, the copyright holders give + permission to link the code of this program with any edition of + the Qt library by Trolltech AS, Norway (or with modified versions + of Qt that use the same license as Qt), and distribute linked + combinations including the two. You must obey the GNU General + Public License in all respects for all of the code used other than + Qt. If you modify this file, you may extend this exception to + your version of the file, but you are not obligated to do so. If + you do not wish to do so, delete this exception statement from + your version. +*/ + +#include "config.h" + +#include <kglobal.h> +#include <klocale.h> +#include <kdebug.h> + +#include "lunarphase.h" + +LunarPhase::LunarPhase( Hemisphere hemisphere ) +{ + mHemisphere = hemisphere; +} + +LunarPhase::~LunarPhase() +{ +} + +void LunarPhase::setHemisphere( Hemisphere hemisphere ) +{ + mHemisphere = hemisphere; +} + +LunarPhase::Hemisphere LunarPhase::hemisphere() const +{ + return( mHemisphere ); +} + +QString LunarPhase::hemisphereStr() const +{ + return hemisphereName( mHemisphere ); +} + +QString LunarPhase::hemisphereName( LunarPhase::Hemisphere hemisphere ) +{ + switch( hemisphere ) { + case Northern: + default: + return( i18n( "Northern" ) ); + break; + case Southern: + return( i18n( "Southern" ) ); + break; + } +} + +QString LunarPhase::phaseStr( const QDate &date ) const +{ + return phaseName( phase( date ) ); +} + +QString LunarPhase::phaseName( LunarPhase::Phase phase ) +{ + switch ( phase ) { + case New: + return( i18n( "New Moon" ) ); + break; + case Full: + return( i18n( "Full Moon" ) ); + break; + case FirstQ: + return( i18n( "First Quarter Moon" ) ); + break; + case LastQ: + return( i18n( "Last Quarter Moon" ) ); + break; + default: + case None: + return( QString::null ); + break; + } +} + +LunarPhase::Phase LunarPhase::phase( const QDate &date ) const +{ + Phase retPhase = None; + + // compute percent-full for the middle of today and yesterday. + QTime noontime( 12, 0, 0 ); + QDateTime today( date, noontime ); + double todayPer = percentFull( today.toTime_t() ); + QDateTime yesterday( date.addDays(-1), noontime ); + double yesterdayPer = percentFull( yesterday.toTime_t() ); + + if ( ( todayPer < 0.50 ) && ( yesterdayPer > 0.50 ) ) { + retPhase = New; + } else if ( ( todayPer > 99.50 ) && ( yesterdayPer < 99.50 ) ) { + retPhase = Full; + } else { + // compute percent-full for the start of today. + QTime sqt( 0, 0, 0 ); + QDateTime start( date, sqt ); + double startPer = percentFull( start.toTime_t() ); + // compute percent-full for the end of today. + QTime eqt( 23, 59, 59 ); + QDateTime end( date, eqt ); + double endPer = percentFull( end.toTime_t() ); + + if ( ( startPer <= 50 ) && ( endPer > 50 ) ) { + if ( mHemisphere == Northern ) { + retPhase = FirstQ; + } else { + retPhase = LastQ; + } + } + if ( ( endPer <= 50 ) && ( startPer > 50 ) ) { + if ( mHemisphere == Northern ) { + retPhase = LastQ; + } else { + retPhase = FirstQ; + } + } + // Note: if you want to support crescent and gibbous phases then please + // read the source for the original BSD 'pom' program. + } + return( retPhase ); +} + +/* + * 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 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 HAVE_SYS_CDEFS_H +#include <sys/cdefs.h> +#endif + +/* + * 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> +#if HAVE_ERR_H +#include <err.h> +#endif +#include <math.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 */ + +/* + * percentFull -- + * return phase of the moon as a percentage of full + */ +double LunarPhase::percentFull( uint tmpt ) const +{ + double N, Msol, Ec, LambdaSol, l, Mm, Ev, Ac, A3, Mmprime; + double A4, lprime, V, ldprime, D, Nm; + + double days; + days = ( tmpt - EPOCH_MINUS_1970 * 86400 ) / 86400.0; + + N = 360 * days / 365.242191; /* sec 46 #3 */ + adj360(&N); + Msol = N + EPSILONg - RHOg; /* sec 46 #4 */ + adj360(&Msol); + Ec = 360 / PI * ECCEN * sin(degreesToRadians(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(degreesToRadians(2*(l - LambdaSol) - Mm)); /* sec 65 #7 */ + Ac = 0.1858 * sin(degreesToRadians(Msol)); /* sec 65 #8 */ + A3 = 0.37 * sin(degreesToRadians(Msol)); + Mmprime = Mm + Ev - Ac - A3; /* sec 65 #9 */ + Ec = 6.2886 * sin(degreesToRadians(Mmprime)); /* sec 65 #10 */ + A4 = 0.214 * sin(degreesToRadians(2 * Mmprime)); /* sec 65 #11 */ + lprime = l + Ev + Ec - Ac + A4; /* sec 65 #12 */ + V = 0.6583 * sin(degreesToRadians(2 * (lprime - LambdaSol))); /* sec 65 #13 */ + ldprime = lprime + V; /* sec 65 #14 */ + D = ldprime - LambdaSol; /* sec 67 #2 */ + return(50.0 * (1 - cos(degreesToRadians(D)))); /* sec 67 #3 */ +} + +/* + * degreesToRadians -- + * convert degrees to radians + */ +double LunarPhase::degreesToRadians( double degree ) const +{ + return( degree * PI / 180 ); +} + +/* + * adj360 -- + * adjust value so 0 <= degree <= 360 + */ +void LunarPhase::adj360( double *degree ) const +{ + for( ;; ) + if( *degree < 0 ) + *degree += 360; + else if( *degree > 360 ) + *degree -= 360; + else + break; +} |