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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/************************************************************************
* Copyright (C) 1996-2012, International Business Machines Corporation
* and others. All Rights Reserved.
************************************************************************
* 2003-nov-07 srl Port from Java
*/
#include "astro.h"
#if !UCONFIG_NO_FORMATTING
#include "unicode/calendar.h"
#include <math.h>
#include <float.h>
#include "unicode/putil.h"
#include "uhash.h"
#include "umutex.h"
#include "ucln_in.h"
#include "putilimp.h"
#include <stdio.h> // for toString()
#if defined (PI)
#undef PI
#endif
#ifdef U_DEBUG_ASTRO
# include "uresimp.h" // for debugging
static void debug_astro_loc(const char *f, int32_t l)
{
fprintf(stderr, "%s:%d: ", f, l);
}
static void debug_astro_msg(const char *pat, ...)
{
va_list ap;
va_start(ap, pat);
vfprintf(stderr, pat, ap);
fflush(stderr);
}
#include "unicode/datefmt.h"
#include "unicode/ustring.h"
static const char * debug_astro_date(UDate d) {
static char gStrBuf[1024];
static DateFormat *df = nullptr;
if(df == nullptr) {
df = DateFormat::createDateTimeInstance(DateFormat::MEDIUM, DateFormat::MEDIUM, Locale::getUS());
df->adoptTimeZone(TimeZone::getGMT()->clone());
}
UnicodeString str;
df->format(d,str);
u_austrncpy(gStrBuf,str.getTerminatedBuffer(),sizeof(gStrBuf)-1);
return gStrBuf;
}
// must use double parens, i.e.: U_DEBUG_ASTRO_MSG(("four is: %d",4));
#define U_DEBUG_ASTRO_MSG(x) {debug_astro_loc(__FILE__,__LINE__);debug_astro_msg x;}
#else
#define U_DEBUG_ASTRO_MSG(x)
#endif
static inline UBool isINVALID(double d) {
return(uprv_isNaN(d));
}
static icu::UMutex ccLock;
U_CDECL_BEGIN
static UBool calendar_astro_cleanup() {
return true;
}
U_CDECL_END
U_NAMESPACE_BEGIN
/**
* The number of standard hours in one sidereal day.
* Approximately 24.93.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
#define SIDEREAL_DAY (23.93446960027)
/**
* The number of sidereal hours in one mean solar day.
* Approximately 24.07.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
#define SOLAR_DAY (24.065709816)
/**
* The average number of solar days from one new moon to the next. This is the time
* it takes for the moon to return the same ecliptic longitude as the sun.
* It is longer than the sidereal month because the sun's longitude increases
* during the year due to the revolution of the earth around the sun.
* Approximately 29.53.
*
* @see #SIDEREAL_MONTH
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
const double CalendarAstronomer::SYNODIC_MONTH = 29.530588853;
/**
* The average number of days it takes
* for the moon to return to the same ecliptic longitude relative to the
* stellar background. This is referred to as the sidereal month.
* It is shorter than the synodic month due to
* the revolution of the earth around the sun.
* Approximately 27.32.
*
* @see #SYNODIC_MONTH
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
#define SIDEREAL_MONTH 27.32166
/**
* The average number number of days between successive vernal equinoxes.
* Due to the precession of the earth's
* axis, this is not precisely the same as the sidereal year.
* Approximately 365.24
*
* @see #SIDEREAL_YEAR
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
#define TROPICAL_YEAR 365.242191
/**
* The average number of days it takes
* for the sun to return to the same position against the fixed stellar
* background. This is the duration of one orbit of the earth about the sun
* as it would appear to an outside observer.
* Due to the precession of the earth's
* axis, this is not precisely the same as the tropical year.
* Approximately 365.25.
*
* @see #TROPICAL_YEAR
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
#define SIDEREAL_YEAR 365.25636
//-------------------------------------------------------------------------
// Time-related constants
//-------------------------------------------------------------------------
/**
* The number of milliseconds in one second.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
#define SECOND_MS U_MILLIS_PER_SECOND
/**
* The number of milliseconds in one minute.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
#define MINUTE_MS U_MILLIS_PER_MINUTE
/**
* The number of milliseconds in one hour.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
#define HOUR_MS U_MILLIS_PER_HOUR
/**
* The number of milliseconds in one day.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
#define DAY_MS U_MILLIS_PER_DAY
/**
* The start of the julian day numbering scheme used by astronomers, which
* is 1/1/4713 BC (Julian), 12:00 GMT. This is given as the number of milliseconds
* since 1/1/1970 AD (Gregorian), a negative number.
* Note that julian day numbers and
* the Julian calendar are <em>not</em> the same thing. Also note that
* julian days start at <em>noon</em>, not midnight.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
#define JULIAN_EPOCH_MS -210866760000000.0
/**
* Milliseconds value for 0.0 January 2000 AD.
*/
#define EPOCH_2000_MS 946598400000.0
//-------------------------------------------------------------------------
// Assorted private data used for conversions
//-------------------------------------------------------------------------
// My own copies of these so compilers are more likely to optimize them away
const double CalendarAstronomer::PI = 3.14159265358979323846;
#define CalendarAstronomer_PI2 (CalendarAstronomer::PI*2.0)
#define RAD_HOUR ( 12 / CalendarAstronomer::PI ) // radians -> hours
#define DEG_RAD ( CalendarAstronomer::PI / 180 ) // degrees -> radians
#define RAD_DEG ( 180 / CalendarAstronomer::PI ) // radians -> degrees
/***
* Given 'value', add or subtract 'range' until 0 <= 'value' < range.
* The modulus operator.
*/
inline static double normalize(double value, double range) {
return value - range * ClockMath::floorDivide(value, range);
}
/**
* Normalize an angle so that it's in the range 0 - 2pi.
* For positive angles this is just (angle % 2pi), but the Java
* mod operator doesn't work that way for negative numbers....
*/
inline static double norm2PI(double angle) {
return normalize(angle, CalendarAstronomer::PI * 2.0);
}
/**
* Normalize an angle into the range -PI - PI
*/
inline static double normPI(double angle) {
return normalize(angle + CalendarAstronomer::PI, CalendarAstronomer::PI * 2.0) - CalendarAstronomer::PI;
}
//-------------------------------------------------------------------------
// Constructors
//-------------------------------------------------------------------------
/**
* Construct a new <code>CalendarAstronomer</code> object that is initialized to
* the current date and time.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
CalendarAstronomer::CalendarAstronomer():
fTime(Calendar::getNow()), moonPosition(0,0), moonPositionSet(false) {
clearCache();
}
/**
* Construct a new <code>CalendarAstronomer</code> object that is initialized to
* the specified date and time.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
CalendarAstronomer::CalendarAstronomer(UDate d): fTime(d), moonPosition(0,0), moonPositionSet(false) {
clearCache();
}
CalendarAstronomer::~CalendarAstronomer()
{
}
//-------------------------------------------------------------------------
// Time and date getters and setters
//-------------------------------------------------------------------------
/**
* Set the current date and time of this <code>CalendarAstronomer</code> object. All
* astronomical calculations are performed based on this time setting.
*
* @param aTime the date and time, expressed as the number of milliseconds since
* 1/1/1970 0:00 GMT (Gregorian).
*
* @see #setDate
* @see #getTime
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
void CalendarAstronomer::setTime(UDate aTime) {
fTime = aTime;
clearCache();
}
/**
* Get the current time of this <code>CalendarAstronomer</code> object,
* represented as the number of milliseconds since
* 1/1/1970 AD 0:00 GMT (Gregorian).
*
* @see #setTime
* @see #getDate
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
UDate CalendarAstronomer::getTime() {
return fTime;
}
/**
* Get the current time of this <code>CalendarAstronomer</code> object,
* expressed as a "julian day number", which is the number of elapsed
* days since 1/1/4713 BC (Julian), 12:00 GMT.
*
* @see #setJulianDay
* @see #JULIAN_EPOCH_MS
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
double CalendarAstronomer::getJulianDay() {
if (isINVALID(julianDay)) {
julianDay = (fTime - JULIAN_EPOCH_MS) / static_cast<double>(DAY_MS);
}
return julianDay;
}
//-------------------------------------------------------------------------
// Coordinate transformations, all based on the current time of this object
//-------------------------------------------------------------------------
/**
* Convert from ecliptic to equatorial coordinates.
*
* @param eclipLong The ecliptic longitude
* @param eclipLat The ecliptic latitude
*
* @return The corresponding point in equatorial coordinates.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong, double eclipLat)
{
// See page 42 of "Practical Astronomy with your Calculator",
// by Peter Duffet-Smith, for details on the algorithm.
double obliq = eclipticObliquity();
double sinE = ::sin(obliq);
double cosE = cos(obliq);
double sinL = ::sin(eclipLong);
double cosL = cos(eclipLong);
double sinB = ::sin(eclipLat);
double cosB = cos(eclipLat);
double tanB = tan(eclipLat);
result.set(atan2(sinL*cosE - tanB*sinE, cosL),
asin(sinB*cosE + cosB*sinE*sinL) );
return result;
}
//-------------------------------------------------------------------------
// The Sun
//-------------------------------------------------------------------------
//
// Parameters of the Sun's orbit as of the epoch Jan 0.0 1990
// Angles are in radians (after multiplying by CalendarAstronomer::PI/180)
//
#define JD_EPOCH 2447891.5 // Julian day of epoch
#define SUN_ETA_G (279.403303 * CalendarAstronomer::PI/180) // Ecliptic longitude at epoch
#define SUN_OMEGA_G (282.768422 * CalendarAstronomer::PI/180) // Ecliptic longitude of perigee
#define SUN_E 0.016713 // Eccentricity of orbit
//double sunR0 1.495585e8 // Semi-major axis in KM
//double sunTheta0 (0.533128 * CalendarAstronomer::PI/180) // Angular diameter at R0
// The following three methods, which compute the sun parameters
// given above for an arbitrary epoch (whatever time the object is
// set to), make only a small difference as compared to using the
// above constants. E.g., Sunset times might differ by ~12
// seconds. Furthermore, the eta-g computation is befuddled by
// Duffet-Smith's incorrect coefficients (p.86). I've corrected
// the first-order coefficient but the others may be off too - no
// way of knowing without consulting another source.
// /**
// * Return the sun's ecliptic longitude at perigee for the current time.
// * See Duffett-Smith, p. 86.
// * @return radians
// */
// private double getSunOmegaG() {
// double T = getJulianCentury();
// return (281.2208444 + (1.719175 + 0.000452778*T)*T) * DEG_RAD;
// }
// /**
// * Return the sun's ecliptic longitude for the current time.
// * See Duffett-Smith, p. 86.
// * @return radians
// */
// private double getSunEtaG() {
// double T = getJulianCentury();
// //return (279.6966778 + (36000.76892 + 0.0003025*T)*T) * DEG_RAD;
// //
// // The above line is from Duffett-Smith, and yields manifestly wrong
// // results. The below constant is derived empirically to match the
// // constant he gives for the 1990 EPOCH.
// //
// return (279.6966778 + (-0.3262541582718024 + 0.0003025*T)*T) * DEG_RAD;
// }
// /**
// * Return the sun's eccentricity of orbit for the current time.
// * See Duffett-Smith, p. 86.
// * @return double
// */
// private double getSunE() {
// double T = getJulianCentury();
// return 0.01675104 - (0.0000418 + 0.000000126*T)*T;
// }
/**
* Find the "true anomaly" (longitude) of an object from
* its mean anomaly and the eccentricity of its orbit. This uses
* an iterative solution to Kepler's equation.
*
* @param meanAnomaly The object's longitude calculated as if it were in
* a regular, circular orbit, measured in radians
* from the point of perigee.
*
* @param eccentricity The eccentricity of the orbit
*
* @return The true anomaly (longitude) measured in radians
*/
static double trueAnomaly(double meanAnomaly, double eccentricity)
{
// First, solve Kepler's equation iteratively
// Duffett-Smith, p.90
double delta;
double E = meanAnomaly;
do {
delta = E - eccentricity * ::sin(E) - meanAnomaly;
E = E - delta / (1 - eccentricity * ::cos(E));
}
while (uprv_fabs(delta) > 1e-5); // epsilon = 1e-5 rad
return 2.0 * ::atan( ::tan(E/2) * ::sqrt( (1+eccentricity)
/(1-eccentricity) ) );
}
/**
* The longitude of the sun at the time specified by this object.
* The longitude is measured in radians along the ecliptic
* from the "first point of Aries," the point at which the ecliptic
* crosses the earth's equatorial plane at the vernal equinox.
* <p>
* Currently, this method uses an approximation of the two-body Kepler's
* equation for the earth and the sun. It does not take into account the
* perturbations caused by the other planets, the moon, etc.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
double CalendarAstronomer::getSunLongitude()
{
// See page 86 of "Practical Astronomy with your Calculator",
// by Peter Duffet-Smith, for details on the algorithm.
if (isINVALID(sunLongitude)) {
getSunLongitude(getJulianDay(), sunLongitude, meanAnomalySun);
}
return sunLongitude;
}
/**
* TODO Make this public when the entire class is package-private.
*/
/*public*/ void CalendarAstronomer::getSunLongitude(double jDay, double &longitude, double &meanAnomaly)
{
// See page 86 of "Practical Astronomy with your Calculator",
// by Peter Duffet-Smith, for details on the algorithm.
double day = jDay - JD_EPOCH; // Days since epoch
// Find the angular distance the sun in a fictitious
// circular orbit has travelled since the epoch.
double epochAngle = norm2PI(CalendarAstronomer_PI2/TROPICAL_YEAR*day);
// The epoch wasn't at the sun's perigee; find the angular distance
// since perigee, which is called the "mean anomaly"
meanAnomaly = norm2PI(epochAngle + SUN_ETA_G - SUN_OMEGA_G);
// Now find the "true anomaly", e.g. the real solar longitude
// by solving Kepler's equation for an elliptical orbit
// NOTE: The 3rd ed. of the book lists omega_g and eta_g in different
// equations; omega_g is to be correct.
longitude = norm2PI(trueAnomaly(meanAnomaly, SUN_E) + SUN_OMEGA_G);
}
/**
* Constant representing the winter solstice.
* For use with {@link #getSunTime getSunTime}.
* Note: In this case, "winter" refers to the northern hemisphere's seasons.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
double CalendarAstronomer::WINTER_SOLSTICE() {
return ((CalendarAstronomer::PI*3)/2);
}
CalendarAstronomer::AngleFunc::~AngleFunc() {}
/**
* Find the next time at which the sun's ecliptic longitude will have
* the desired value.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
class SunTimeAngleFunc : public CalendarAstronomer::AngleFunc {
public:
virtual ~SunTimeAngleFunc();
virtual double eval(CalendarAstronomer& a) override { return a.getSunLongitude(); }
};
SunTimeAngleFunc::~SunTimeAngleFunc() {}
UDate CalendarAstronomer::getSunTime(double desired, UBool next)
{
SunTimeAngleFunc func;
return timeOfAngle( func,
desired,
TROPICAL_YEAR,
MINUTE_MS,
next);
}
//-------------------------------------------------------------------------
// The Moon
//-------------------------------------------------------------------------
#define moonL0 (318.351648 * CalendarAstronomer::PI/180 ) // Mean long. at epoch
#define moonP0 ( 36.340410 * CalendarAstronomer::PI/180 ) // Mean long. of perigee
#define moonN0 ( 318.510107 * CalendarAstronomer::PI/180 ) // Mean long. of node
#define moonI ( 5.145366 * CalendarAstronomer::PI/180 ) // Inclination of orbit
#define moonE ( 0.054900 ) // Eccentricity of orbit
// These aren't used right now
#define moonA ( 3.84401e5 ) // semi-major axis (km)
#define moonT0 ( 0.5181 * CalendarAstronomer::PI/180 ) // Angular size at distance A
#define moonPi ( 0.9507 * CalendarAstronomer::PI/180 ) // Parallax at distance A
/**
* The position of the moon at the time set on this
* object, in equatorial coordinates.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
const CalendarAstronomer::Equatorial& CalendarAstronomer::getMoonPosition()
{
//
// See page 142 of "Practical Astronomy with your Calculator",
// by Peter Duffet-Smith, for details on the algorithm.
//
if (moonPositionSet == false) {
// Calculate the solar longitude. Has the side effect of
// filling in "meanAnomalySun" as well.
getSunLongitude();
//
// Find the # of days since the epoch of our orbital parameters.
// TODO: Convert the time of day portion into ephemeris time
//
double day = getJulianDay() - JD_EPOCH; // Days since epoch
// Calculate the mean longitude and anomaly of the moon, based on
// a circular orbit. Similar to the corresponding solar calculation.
double meanLongitude = norm2PI(13.1763966*PI/180*day + moonL0);
double meanAnomalyMoon = norm2PI(meanLongitude - 0.1114041*PI/180 * day - moonP0);
//
// Calculate the following corrections:
// Evection: the sun's gravity affects the moon's eccentricity
// Annual Eqn: variation in the effect due to earth-sun distance
// A3: correction factor (for ???)
//
double evection = 1.2739*PI/180 * ::sin(2 * (meanLongitude - sunLongitude)
- meanAnomalyMoon);
double annual = 0.1858*PI/180 * ::sin(meanAnomalySun);
double a3 = 0.3700*PI/180 * ::sin(meanAnomalySun);
meanAnomalyMoon += evection - annual - a3;
//
// More correction factors:
// center equation of the center correction
// a4 yet another error correction (???)
//
// TODO: Skip the equation of the center correction and solve Kepler's eqn?
//
double center = 6.2886*PI/180 * ::sin(meanAnomalyMoon);
double a4 = 0.2140*PI/180 * ::sin(2 * meanAnomalyMoon);
// Now find the moon's corrected longitude
double moonLongitude = meanLongitude + evection + center - annual + a4;
//
// And finally, find the variation, caused by the fact that the sun's
// gravitational pull on the moon varies depending on which side of
// the earth the moon is on
//
double variation = 0.6583*CalendarAstronomer::PI/180 * ::sin(2*(moonLongitude - sunLongitude));
moonLongitude += variation;
//
// What we've calculated so far is the moon's longitude in the plane
// of its own orbit. Now map to the ecliptic to get the latitude
// and longitude. First we need to find the longitude of the ascending
// node, the position on the ecliptic where it is crossed by the moon's
// orbit as it crosses from the southern to the northern hemisphere.
//
double nodeLongitude = norm2PI(moonN0 - 0.0529539*PI/180 * day);
nodeLongitude -= 0.16*PI/180 * ::sin(meanAnomalySun);
double y = ::sin(moonLongitude - nodeLongitude);
double x = cos(moonLongitude - nodeLongitude);
moonEclipLong = ::atan2(y*cos(moonI), x) + nodeLongitude;
double moonEclipLat = ::asin(y * ::sin(moonI));
eclipticToEquatorial(moonPosition, moonEclipLong, moonEclipLat);
moonPositionSet = true;
}
return moonPosition;
}
/**
* The "age" of the moon at the time specified in this object.
* This is really the angle between the
* current ecliptic longitudes of the sun and the moon,
* measured in radians.
*
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
double CalendarAstronomer::getMoonAge() {
// See page 147 of "Practical Astronomy with your Calculator",
// by Peter Duffet-Smith, for details on the algorithm.
//
// Force the moon's position to be calculated. We're going to use
// some the intermediate results cached during that calculation.
//
getMoonPosition();
return norm2PI(moonEclipLong - sunLongitude);
}
/**
* Constant representing a new moon.
* For use with {@link #getMoonTime getMoonTime}
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
CalendarAstronomer::MoonAge CalendarAstronomer::NEW_MOON() {
return CalendarAstronomer::MoonAge(0);
}
/**
* Constant representing the moon's last quarter.
* For use with {@link #getMoonTime getMoonTime}
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
class MoonTimeAngleFunc : public CalendarAstronomer::AngleFunc {
public:
virtual ~MoonTimeAngleFunc();
virtual double eval(CalendarAstronomer& a) override { return a.getMoonAge(); }
};
MoonTimeAngleFunc::~MoonTimeAngleFunc() {}
/*const CalendarAstronomer::MoonAge CalendarAstronomer::LAST_QUARTER() {
return CalendarAstronomer::MoonAge((CalendarAstronomer::PI*3)/2);
}*/
/**
* Find the next or previous time at which the moon will be in the
* desired phase.
* <p>
* @param desired The desired phase of the moon.
* @param next <tt>true</tt> if the next occurrence of the phase
* is desired, <tt>false</tt> for the previous occurrence.
* @internal
* @deprecated ICU 2.4. This class may be removed or modified.
*/
UDate CalendarAstronomer::getMoonTime(const CalendarAstronomer::MoonAge& desired, UBool next) {
MoonTimeAngleFunc func;
return timeOfAngle( func,
desired.value,
SYNODIC_MONTH,
MINUTE_MS,
next);
}
//-------------------------------------------------------------------------
// Interpolation methods for finding the time at which a given event occurs
//-------------------------------------------------------------------------
UDate CalendarAstronomer::timeOfAngle(AngleFunc& func, double desired,
double periodDays, double epsilon, UBool next)
{
// Find the value of the function at the current time
double lastAngle = func.eval(*this);
// Find out how far we are from the desired angle
double deltaAngle = norm2PI(desired - lastAngle) ;
// Using the average period, estimate the next (or previous) time at
// which the desired angle occurs.
double deltaT = (deltaAngle + (next ? 0.0 : - CalendarAstronomer_PI2 )) * (periodDays*DAY_MS) / CalendarAstronomer_PI2;
double lastDeltaT = deltaT; // Liu
UDate startTime = fTime; // Liu
setTime(fTime + uprv_ceil(deltaT));
// Now iterate until we get the error below epsilon. Throughout
// this loop we use normPI to get values in the range -Pi to Pi,
// since we're using them as correction factors rather than absolute angles.
do {
// Evaluate the function at the time we've estimated
double angle = func.eval(*this);
// Find the # of milliseconds per radian at this point on the curve
double factor = uprv_fabs(deltaT / normPI(angle-lastAngle));
// Correct the time estimate based on how far off the angle is
deltaT = normPI(desired - angle) * factor;
// HACK:
//
// If abs(deltaT) begins to diverge we need to quit this loop.
// This only appears to happen when attempting to locate, for
// example, a new moon on the day of the new moon. E.g.:
//
// This result is correct:
// newMoon(7508(Mon Jul 23 00:00:00 CST 1990,false))=
// Sun Jul 22 10:57:41 CST 1990
//
// But attempting to make the same call a day earlier causes deltaT
// to diverge:
// CalendarAstronomer.timeOfAngle() diverging: 1.348508727575625E9 ->
// 1.3649828540224032E9
// newMoon(7507(Sun Jul 22 00:00:00 CST 1990,false))=
// Sun Jul 08 13:56:15 CST 1990
//
// As a temporary solution, we catch this specific condition and
// adjust our start time by one eighth period days (either forward
// or backward) and try again.
// Liu 11/9/00
if (uprv_fabs(deltaT) > uprv_fabs(lastDeltaT)) {
double delta = uprv_ceil (periodDays * DAY_MS / 8.0);
setTime(startTime + (next ? delta : -delta));
return timeOfAngle(func, desired, periodDays, epsilon, next);
}
lastDeltaT = deltaT;
lastAngle = angle;
setTime(fTime + uprv_ceil(deltaT));
}
while (uprv_fabs(deltaT) > epsilon);
return fTime;
}
/**
* Return the obliquity of the ecliptic (the angle between the ecliptic
* and the earth's equator) at the current time. This varies due to
* the precession of the earth's axis.
*
* @return the obliquity of the ecliptic relative to the equator,
* measured in radians.
*/
double CalendarAstronomer::eclipticObliquity() {
const double epoch = 2451545.0; // 2000 AD, January 1.5
double T = (getJulianDay() - epoch) / 36525;
double eclipObliquity = 23.439292
- 46.815/3600 * T
- 0.0006/3600 * T*T
+ 0.00181/3600 * T*T*T;
return eclipObliquity * DEG_RAD;
}
//-------------------------------------------------------------------------
// Private data
//-------------------------------------------------------------------------
void CalendarAstronomer::clearCache() {
const double INVALID = uprv_getNaN();
julianDay = INVALID;
sunLongitude = INVALID;
meanAnomalySun = INVALID;
moonEclipLong = INVALID;
moonPositionSet = false;
}
// Debugging functions
UnicodeString CalendarAstronomer::Ecliptic::toString() const
{
#ifdef U_DEBUG_ASTRO
char tmp[800];
snprintf(tmp, sizeof(tmp), "[%.5f,%.5f]", longitude*RAD_DEG, latitude*RAD_DEG);
return UnicodeString(tmp, "");
#else
return {};
#endif
}
UnicodeString CalendarAstronomer::Equatorial::toString() const
{
#ifdef U_DEBUG_ASTRO
char tmp[400];
snprintf(tmp, sizeof(tmp), "%f,%f",
(ascension*RAD_DEG), (declination*RAD_DEG));
return UnicodeString(tmp, "");
#else
return {};
#endif
}
// =============== Calendar Cache ================
void CalendarCache::createCache(CalendarCache** cache, UErrorCode& status) {
ucln_i18n_registerCleanup(UCLN_I18N_ASTRO_CALENDAR, calendar_astro_cleanup);
if(cache == nullptr) {
status = U_MEMORY_ALLOCATION_ERROR;
} else {
*cache = new CalendarCache(32, status);
if(U_FAILURE(status)) {
delete *cache;
*cache = nullptr;
}
}
}
int32_t CalendarCache::get(CalendarCache** cache, int32_t key, UErrorCode &status) {
int32_t res;
if(U_FAILURE(status)) {
return 0;
}
umtx_lock(&ccLock);
if(*cache == nullptr) {
createCache(cache, status);
if(U_FAILURE(status)) {
umtx_unlock(&ccLock);
return 0;
}
}
res = uhash_igeti((*cache)->fTable, key);
U_DEBUG_ASTRO_MSG(("%p: GET: [%d] == %d\n", (*cache)->fTable, key, res));
umtx_unlock(&ccLock);
return res;
}
void CalendarCache::put(CalendarCache** cache, int32_t key, int32_t value, UErrorCode &status) {
if(U_FAILURE(status)) {
return;
}
umtx_lock(&ccLock);
if(*cache == nullptr) {
createCache(cache, status);
if(U_FAILURE(status)) {
umtx_unlock(&ccLock);
return;
}
}
uhash_iputi((*cache)->fTable, key, value, &status);
U_DEBUG_ASTRO_MSG(("%p: PUT: [%d] := %d\n", (*cache)->fTable, key, value));
umtx_unlock(&ccLock);
}
CalendarCache::CalendarCache(int32_t size, UErrorCode &status) {
fTable = uhash_openSize(uhash_hashLong, uhash_compareLong, nullptr, size, &status);
U_DEBUG_ASTRO_MSG(("%p: Opening.\n", fTable));
}
CalendarCache::~CalendarCache() {
if(fTable != nullptr) {
U_DEBUG_ASTRO_MSG(("%p: Closing.\n", fTable));
uhash_close(fTable);
}
}
U_NAMESPACE_END
#endif // !UCONFIG_NO_FORMATTING
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