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tdepim/libkholidays/lunarphase.cpp

292 lines
9.5 KiB

/*
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 );
}
TQString LunarPhase::hemisphereStr() const
{
return hemisphereName( mHemisphere );
}
TQString LunarPhase::hemisphereName( LunarPhase::Hemisphere hemisphere )
{
switch( hemisphere ) {
case Northern:
default:
return( i18n( "Northern" ) );
break;
case Southern:
return( i18n( "Southern" ) );
break;
}
}
TQString LunarPhase::phaseStr( const TQDate &date ) const
{
return phaseName( phase( date ) );
}
TQString 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( TQString::null );
break;
}
}
LunarPhase::Phase LunarPhase::phase( const TQDate &date ) const
{
Phase retPhase = None;
// compute percent-full for the middle of today and yesterday.
TQTime noontime( 12, 0, 0 );
TQDateTime today( date, noontime );
double todayPer = percentFull( today.toTime_t() );
TQDateTime 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.
TQTime sqt( 0, 0, 0 );
TQDateTime start( date, sqt );
double startPer = percentFull( start.toTime_t() );
// compute percent-full for the end of today.
TQTime eqt( 23, 59, 59 );
TQDateTime 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;
}