kde-playground/kdepimlibs/kholidays/lunarphase.cpp
2015-04-14 21:49:29 +00:00

235 lines
8.2 KiB
C++

/*
This file is part of the kholidays library.
Copyright (c) 2004,2007,2009 Allen Winter <winter@kde.org>
Copyright (c) 1989, 1993 //krazy:exclude=copyright
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 Library 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 Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include "lunarphase.h"
#include <config-kholidays.h>
#include <KDebug>
#include <KGlobal>
#include <KLocalizedString>
#include <QtCore/QDateTime>
using namespace KHolidays;
static double percentFull( uint tmpt );
static double degreesToRadians( double degree );
static void adj360( double *degree );
QString LunarPhase::phaseNameAtDate( const QDate &date )
{
return phaseName( phaseAtDate( date ) );
}
QString LunarPhase::phaseName( LunarPhase::Phase phase )
{
switch ( phase ) {
case NewMoon:
return( i18n( "New Moon" ) );
case FullMoon:
return( i18n( "Full Moon" ) );
case FirstQuarter:
return( i18n( "First Quarter Moon" ) );
case LastQuarter:
return( i18n( "Last Quarter Moon" ) );
default:
case None:
return QString();
}
}
LunarPhase::Phase LunarPhase::phaseAtDate( const QDate &date )
{
Phase retPhase = None;
// compute percent-full for the middle of today and yesterday.
const QTime anytime( 12, 0, 0 );
const QDateTime today( date, anytime, Qt::UTC );
const double todayPer = percentFull( today.toTime_t() ) + 0.5;
const QDateTime tomorrow( date.addDays( 1 ), anytime, Qt::UTC );
const double tomorrowPer = percentFull( tomorrow.toTime_t() ) + 0.5;
if ( static_cast<int>( todayPer ) == 100 &&
static_cast<int>( tomorrowPer ) != 100 ) {
retPhase = FullMoon;
} else if ( static_cast<int>( todayPer ) == 0 &&
static_cast<int>( tomorrowPer ) != 0 ) {
retPhase = NewMoon;
} else {
if ( todayPer > 50 && tomorrowPer < 50 ) {
retPhase = LastQuarter;
}
if ( todayPer < 50 && tomorrowPer > 50 ) {
retPhase = FirstQuarter;
}
// 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.
*/
#ifdef 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>
#ifdef HAVE_ERR_H
#include <err.h>
#endif
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
static double PI = 3.14159265358979323846;
/*
* 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.)
*/
static int EPOCH_MINUS_1970 = ( 20 * 365 + 5 - 1 ); /* 20 years, 5 leaps, back 1 day to Jan 0 */
static double EPSILONg = 279.403303; /* solar ecliptic long at EPOCH */
static double RHOg = 282.768422; /* solar ecliptic long of perigee at EPOCH */
static double ECCEN = 0.016713; /* solar orbit eccentricity */
static double lzero = 318.351648; /* lunar mean long at EPOCH */
static double Pzero = 36.340410; /* lunar mean long of perigee at EPOCH */
static double Nzero = 318.510107; /* lunar mean long of node at EPOCH */
/*
* percentFull --
* return phase of the moon as a percentage of full
*/
static double percentFull( uint tmpt )
{
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 */
D = 50.0 * ( 1 - cos( degreesToRadians( D ) ) ); /* sec 67 #3 */
return D;
}
/*
* degreesToRadians --
* convert degrees to radians
*/
static double degreesToRadians( double degree )
{
return ( degree * PI ) / 180.00;
}
/*
* adj360 --
* adjust value so 0 <= degree <= 360
*/
static void adj360( double *degree )
{
for ( ;; ) {
if ( *degree < 0 ) {
*degree += 360;
} else if ( *degree > 360 ) {
*degree -= 360;
} else {
break;
}
}
}