Victor Chang | 7322950 | 2020-09-17 13:39:19 +0100 | [diff] [blame] | 1 | // © 2016 and later: Unicode, Inc. and others. |
| 2 | // License & terms of use: http://www.unicode.org/copyright.html |
| 3 | /************************************************************************ |
| 4 | * Copyright (C) 1996-2008, International Business Machines Corporation * |
| 5 | * and others. All Rights Reserved. * |
| 6 | ************************************************************************ |
| 7 | * 2003-nov-07 srl Port from Java |
| 8 | */ |
| 9 | |
| 10 | #ifndef ASTRO_H |
| 11 | #define ASTRO_H |
| 12 | |
| 13 | #include "unicode/utypes.h" |
| 14 | |
| 15 | #if !UCONFIG_NO_FORMATTING |
| 16 | |
| 17 | #include "gregoimp.h" // for Math |
| 18 | #include "unicode/unistr.h" |
| 19 | |
| 20 | U_NAMESPACE_BEGIN |
| 21 | |
| 22 | /** |
| 23 | * <code>CalendarAstronomer</code> is a class that can perform the calculations to |
| 24 | * determine the positions of the sun and moon, the time of sunrise and |
| 25 | * sunset, and other astronomy-related data. The calculations it performs |
| 26 | * are in some cases quite complicated, and this utility class saves you |
| 27 | * the trouble of worrying about them. |
| 28 | * <p> |
| 29 | * The measurement of time is a very important part of astronomy. Because |
| 30 | * astronomical bodies are constantly in motion, observations are only valid |
| 31 | * at a given moment in time. Accordingly, each <code>CalendarAstronomer</code> |
| 32 | * object has a <code>time</code> property that determines the date |
| 33 | * and time for which its calculations are performed. You can set and |
| 34 | * retrieve this property with {@link #setDate setDate}, {@link #getDate getDate} |
| 35 | * and related methods. |
| 36 | * <p> |
| 37 | * Almost all of the calculations performed by this class, or by any |
| 38 | * astronomer, are approximations to various degrees of accuracy. The |
| 39 | * calculations in this class are mostly modelled after those described |
| 40 | * in the book |
| 41 | * <a href="http://www.amazon.com/exec/obidos/ISBN=0521356997" target="_top"> |
| 42 | * Practical Astronomy With Your Calculator</a>, by Peter J. |
| 43 | * Duffett-Smith, Cambridge University Press, 1990. This is an excellent |
| 44 | * book, and if you want a greater understanding of how these calculations |
| 45 | * are performed it a very good, readable starting point. |
| 46 | * <p> |
| 47 | * <strong>WARNING:</strong> This class is very early in its development, and |
| 48 | * it is highly likely that its API will change to some degree in the future. |
| 49 | * At the moment, it basically does just enough to support {@link IslamicCalendar} |
| 50 | * and {@link ChineseCalendar}. |
| 51 | * |
| 52 | * @author Laura Werner |
| 53 | * @author Alan Liu |
| 54 | * @internal |
| 55 | */ |
| 56 | class U_I18N_API CalendarAstronomer : public UMemory { |
| 57 | public: |
| 58 | // some classes |
| 59 | |
| 60 | public: |
| 61 | /** |
| 62 | * Represents the position of an object in the sky relative to the ecliptic, |
| 63 | * the plane of the earth's orbit around the Sun. |
| 64 | * This is a spherical coordinate system in which the latitude |
| 65 | * specifies the position north or south of the plane of the ecliptic. |
| 66 | * The longitude specifies the position along the ecliptic plane |
| 67 | * relative to the "First Point of Aries", which is the Sun's position in the sky |
| 68 | * at the Vernal Equinox. |
| 69 | * <p> |
| 70 | * Note that Ecliptic objects are immutable and cannot be modified |
| 71 | * once they are constructed. This allows them to be passed and returned by |
| 72 | * value without worrying about whether other code will modify them. |
| 73 | * |
| 74 | * @see CalendarAstronomer.Equatorial |
| 75 | * @see CalendarAstronomer.Horizon |
| 76 | * @internal |
| 77 | */ |
| 78 | class U_I18N_API Ecliptic : public UMemory { |
| 79 | public: |
| 80 | /** |
| 81 | * Constructs an Ecliptic coordinate object. |
| 82 | * <p> |
| 83 | * @param lat The ecliptic latitude, measured in radians. |
| 84 | * @param lon The ecliptic longitude, measured in radians. |
| 85 | * @internal |
| 86 | */ |
| 87 | Ecliptic(double lat = 0, double lon = 0) { |
| 88 | latitude = lat; |
| 89 | longitude = lon; |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * Setter for Ecliptic Coordinate object |
| 94 | * @param lat The ecliptic latitude, measured in radians. |
| 95 | * @param lon The ecliptic longitude, measured in radians. |
| 96 | * @internal |
| 97 | */ |
| 98 | void set(double lat, double lon) { |
| 99 | latitude = lat; |
| 100 | longitude = lon; |
| 101 | } |
| 102 | |
| 103 | /** |
| 104 | * Return a string representation of this object |
| 105 | * @internal |
| 106 | */ |
| 107 | UnicodeString toString() const; |
| 108 | |
| 109 | /** |
| 110 | * The ecliptic latitude, in radians. This specifies an object's |
| 111 | * position north or south of the plane of the ecliptic, |
| 112 | * with positive angles representing north. |
| 113 | * @internal |
| 114 | */ |
| 115 | double latitude; |
| 116 | |
| 117 | /** |
| 118 | * The ecliptic longitude, in radians. |
| 119 | * This specifies an object's position along the ecliptic plane |
| 120 | * relative to the "First Point of Aries", which is the Sun's position |
| 121 | * in the sky at the Vernal Equinox, |
| 122 | * with positive angles representing east. |
| 123 | * <p> |
| 124 | * A bit of trivia: the first point of Aries is currently in the |
| 125 | * constellation Pisces, due to the precession of the earth's axis. |
| 126 | * @internal |
| 127 | */ |
| 128 | double longitude; |
| 129 | }; |
| 130 | |
| 131 | /** |
| 132 | * Represents the position of an |
| 133 | * object in the sky relative to the plane of the earth's equator. |
| 134 | * The <i>Right Ascension</i> specifies the position east or west |
| 135 | * along the equator, relative to the sun's position at the vernal |
| 136 | * equinox. The <i>Declination</i> is the position north or south |
| 137 | * of the equatorial plane. |
| 138 | * <p> |
| 139 | * Note that Equatorial objects are immutable and cannot be modified |
| 140 | * once they are constructed. This allows them to be passed and returned by |
| 141 | * value without worrying about whether other code will modify them. |
| 142 | * |
| 143 | * @see CalendarAstronomer.Ecliptic |
| 144 | * @see CalendarAstronomer.Horizon |
| 145 | * @internal |
| 146 | */ |
| 147 | class U_I18N_API Equatorial : public UMemory { |
| 148 | public: |
| 149 | /** |
| 150 | * Constructs an Equatorial coordinate object. |
| 151 | * <p> |
| 152 | * @param asc The right ascension, measured in radians. |
| 153 | * @param dec The declination, measured in radians. |
| 154 | * @internal |
| 155 | */ |
| 156 | Equatorial(double asc = 0, double dec = 0) |
| 157 | : ascension(asc), declination(dec) { } |
| 158 | |
| 159 | /** |
| 160 | * Setter |
| 161 | * @param asc The right ascension, measured in radians. |
| 162 | * @param dec The declination, measured in radians. |
| 163 | * @internal |
| 164 | */ |
| 165 | void set(double asc, double dec) { |
| 166 | ascension = asc; |
| 167 | declination = dec; |
| 168 | } |
| 169 | |
| 170 | /** |
| 171 | * Return a string representation of this object, with the |
| 172 | * angles measured in degrees. |
| 173 | * @internal |
| 174 | */ |
| 175 | UnicodeString toString() const; |
| 176 | |
| 177 | /** |
| 178 | * Return a string representation of this object with the right ascension |
| 179 | * measured in hours, minutes, and seconds. |
| 180 | * @internal |
| 181 | */ |
| 182 | //String toHmsString() { |
| 183 | //return radToHms(ascension) + "," + radToDms(declination); |
| 184 | //} |
| 185 | |
| 186 | /** |
| 187 | * The right ascension, in radians. |
| 188 | * This is the position east or west along the equator |
| 189 | * relative to the sun's position at the vernal equinox, |
| 190 | * with positive angles representing East. |
| 191 | * @internal |
| 192 | */ |
| 193 | double ascension; |
| 194 | |
| 195 | /** |
| 196 | * The declination, in radians. |
| 197 | * This is the position north or south of the equatorial plane, |
| 198 | * with positive angles representing north. |
| 199 | * @internal |
| 200 | */ |
| 201 | double declination; |
| 202 | }; |
| 203 | |
| 204 | /** |
| 205 | * Represents the position of an object in the sky relative to |
| 206 | * the local horizon. |
| 207 | * The <i>Altitude</i> represents the object's elevation above the horizon, |
| 208 | * with objects below the horizon having a negative altitude. |
| 209 | * The <i>Azimuth</i> is the geographic direction of the object from the |
| 210 | * observer's position, with 0 representing north. The azimuth increases |
| 211 | * clockwise from north. |
| 212 | * <p> |
| 213 | * Note that Horizon objects are immutable and cannot be modified |
| 214 | * once they are constructed. This allows them to be passed and returned by |
| 215 | * value without worrying about whether other code will modify them. |
| 216 | * |
| 217 | * @see CalendarAstronomer.Ecliptic |
| 218 | * @see CalendarAstronomer.Equatorial |
| 219 | * @internal |
| 220 | */ |
| 221 | class U_I18N_API Horizon : public UMemory { |
| 222 | public: |
| 223 | /** |
| 224 | * Constructs a Horizon coordinate object. |
| 225 | * <p> |
| 226 | * @param alt The altitude, measured in radians above the horizon. |
| 227 | * @param azim The azimuth, measured in radians clockwise from north. |
| 228 | * @internal |
| 229 | */ |
| 230 | Horizon(double alt=0, double azim=0) |
| 231 | : altitude(alt), azimuth(azim) { } |
| 232 | |
| 233 | /** |
| 234 | * Setter for Ecliptic Coordinate object |
| 235 | * @param alt The altitude, measured in radians above the horizon. |
| 236 | * @param azim The azimuth, measured in radians clockwise from north. |
| 237 | * @internal |
| 238 | */ |
| 239 | void set(double alt, double azim) { |
| 240 | altitude = alt; |
| 241 | azimuth = azim; |
| 242 | } |
| 243 | |
| 244 | /** |
| 245 | * Return a string representation of this object, with the |
| 246 | * angles measured in degrees. |
| 247 | * @internal |
| 248 | */ |
| 249 | UnicodeString toString() const; |
| 250 | |
| 251 | /** |
| 252 | * The object's altitude above the horizon, in radians. |
| 253 | * @internal |
| 254 | */ |
| 255 | double altitude; |
| 256 | |
| 257 | /** |
| 258 | * The object's direction, in radians clockwise from north. |
| 259 | * @internal |
| 260 | */ |
| 261 | double azimuth; |
| 262 | }; |
| 263 | |
| 264 | public: |
| 265 | //------------------------------------------------------------------------- |
| 266 | // Assorted private data used for conversions |
| 267 | //------------------------------------------------------------------------- |
| 268 | |
| 269 | // My own copies of these so compilers are more likely to optimize them away |
| 270 | static const double PI; |
| 271 | |
| 272 | /** |
| 273 | * The average number of solar days from one new moon to the next. This is the time |
| 274 | * it takes for the moon to return the same ecliptic longitude as the sun. |
| 275 | * It is longer than the sidereal month because the sun's longitude increases |
| 276 | * during the year due to the revolution of the earth around the sun. |
| 277 | * Approximately 29.53. |
| 278 | * |
| 279 | * @see #SIDEREAL_MONTH |
| 280 | * @internal |
| 281 | * @deprecated ICU 2.4. This class may be removed or modified. |
| 282 | */ |
| 283 | static const double SYNODIC_MONTH; |
| 284 | |
| 285 | //------------------------------------------------------------------------- |
| 286 | // Constructors |
| 287 | //------------------------------------------------------------------------- |
| 288 | |
| 289 | /** |
| 290 | * Construct a new <code>CalendarAstronomer</code> object that is initialized to |
| 291 | * the current date and time. |
| 292 | * @internal |
| 293 | */ |
| 294 | CalendarAstronomer(); |
| 295 | |
| 296 | /** |
| 297 | * Construct a new <code>CalendarAstronomer</code> object that is initialized to |
| 298 | * the specified date and time. |
| 299 | * @internal |
| 300 | */ |
| 301 | CalendarAstronomer(UDate d); |
| 302 | |
| 303 | /** |
| 304 | * Construct a new <code>CalendarAstronomer</code> object with the given |
| 305 | * latitude and longitude. The object's time is set to the current |
| 306 | * date and time. |
| 307 | * <p> |
| 308 | * @param longitude The desired longitude, in <em>degrees</em> east of |
| 309 | * the Greenwich meridian. |
| 310 | * |
| 311 | * @param latitude The desired latitude, in <em>degrees</em>. Positive |
| 312 | * values signify North, negative South. |
| 313 | * |
| 314 | * @see java.util.Date#getTime() |
| 315 | * @internal |
| 316 | */ |
| 317 | CalendarAstronomer(double longitude, double latitude); |
| 318 | |
| 319 | /** |
| 320 | * Destructor |
| 321 | * @internal |
| 322 | */ |
| 323 | ~CalendarAstronomer(); |
| 324 | |
| 325 | //------------------------------------------------------------------------- |
| 326 | // Time and date getters and setters |
| 327 | //------------------------------------------------------------------------- |
| 328 | |
| 329 | /** |
| 330 | * Set the current date and time of this <code>CalendarAstronomer</code> object. All |
| 331 | * astronomical calculations are performed based on this time setting. |
| 332 | * |
| 333 | * @param aTime the date and time, expressed as the number of milliseconds since |
| 334 | * 1/1/1970 0:00 GMT (Gregorian). |
| 335 | * |
| 336 | * @see #setDate |
| 337 | * @see #getTime |
| 338 | * @internal |
| 339 | */ |
| 340 | void setTime(UDate aTime); |
| 341 | |
| 342 | |
| 343 | /** |
| 344 | * Set the current date and time of this <code>CalendarAstronomer</code> object. All |
| 345 | * astronomical calculations are performed based on this time setting. |
| 346 | * |
| 347 | * @param aTime the date and time, expressed as the number of milliseconds since |
| 348 | * 1/1/1970 0:00 GMT (Gregorian). |
| 349 | * |
| 350 | * @see #getTime |
| 351 | * @internal |
| 352 | */ |
| 353 | void setDate(UDate aDate) { setTime(aDate); } |
| 354 | |
| 355 | /** |
| 356 | * Set the current date and time of this <code>CalendarAstronomer</code> object. All |
| 357 | * astronomical calculations are performed based on this time setting. |
| 358 | * |
| 359 | * @param jdn the desired time, expressed as a "julian day number", |
| 360 | * which is the number of elapsed days since |
| 361 | * 1/1/4713 BC (Julian), 12:00 GMT. Note that julian day |
| 362 | * numbers start at <em>noon</em>. To get the jdn for |
| 363 | * the corresponding midnight, subtract 0.5. |
| 364 | * |
| 365 | * @see #getJulianDay |
| 366 | * @see #JULIAN_EPOCH_MS |
| 367 | * @internal |
| 368 | */ |
| 369 | void setJulianDay(double jdn); |
| 370 | |
| 371 | /** |
| 372 | * Get the current time of this <code>CalendarAstronomer</code> object, |
| 373 | * represented as the number of milliseconds since |
| 374 | * 1/1/1970 AD 0:00 GMT (Gregorian). |
| 375 | * |
| 376 | * @see #setTime |
| 377 | * @see #getDate |
| 378 | * @internal |
| 379 | */ |
| 380 | UDate getTime(); |
| 381 | |
| 382 | /** |
| 383 | * Get the current time of this <code>CalendarAstronomer</code> object, |
| 384 | * expressed as a "julian day number", which is the number of elapsed |
| 385 | * days since 1/1/4713 BC (Julian), 12:00 GMT. |
| 386 | * |
| 387 | * @see #setJulianDay |
| 388 | * @see #JULIAN_EPOCH_MS |
| 389 | * @internal |
| 390 | */ |
| 391 | double getJulianDay(); |
| 392 | |
| 393 | /** |
| 394 | * Return this object's time expressed in julian centuries: |
| 395 | * the number of centuries after 1/1/1900 AD, 12:00 GMT |
| 396 | * |
| 397 | * @see #getJulianDay |
| 398 | * @internal |
| 399 | */ |
| 400 | double getJulianCentury(); |
| 401 | |
| 402 | /** |
| 403 | * Returns the current Greenwich sidereal time, measured in hours |
| 404 | * @internal |
| 405 | */ |
| 406 | double getGreenwichSidereal(); |
| 407 | |
| 408 | private: |
| 409 | double getSiderealOffset(); |
| 410 | public: |
| 411 | /** |
| 412 | * Returns the current local sidereal time, measured in hours |
| 413 | * @internal |
| 414 | */ |
| 415 | double getLocalSidereal(); |
| 416 | |
| 417 | /** |
| 418 | * Converts local sidereal time to Universal Time. |
| 419 | * |
| 420 | * @param lst The Local Sidereal Time, in hours since sidereal midnight |
| 421 | * on this object's current date. |
| 422 | * |
| 423 | * @return The corresponding Universal Time, in milliseconds since |
| 424 | * 1 Jan 1970, GMT. |
| 425 | */ |
| 426 | //private: |
| 427 | double lstToUT(double lst); |
| 428 | |
| 429 | /** |
| 430 | * |
| 431 | * Convert from ecliptic to equatorial coordinates. |
| 432 | * |
| 433 | * @param ecliptic The ecliptic |
| 434 | * @param result Fillin result |
| 435 | * @return reference to result |
| 436 | */ |
| 437 | Equatorial& eclipticToEquatorial(Equatorial& result, const Ecliptic& ecliptic); |
| 438 | |
| 439 | /** |
| 440 | * Convert from ecliptic to equatorial coordinates. |
| 441 | * |
| 442 | * @param eclipLong The ecliptic longitude |
| 443 | * @param eclipLat The ecliptic latitude |
| 444 | * |
| 445 | * @return The corresponding point in equatorial coordinates. |
| 446 | * @internal |
| 447 | */ |
| 448 | Equatorial& eclipticToEquatorial(Equatorial& result, double eclipLong, double eclipLat); |
| 449 | |
| 450 | /** |
| 451 | * Convert from ecliptic longitude to equatorial coordinates. |
| 452 | * |
| 453 | * @param eclipLong The ecliptic longitude |
| 454 | * |
| 455 | * @return The corresponding point in equatorial coordinates. |
| 456 | * @internal |
| 457 | */ |
| 458 | Equatorial& eclipticToEquatorial(Equatorial& result, double eclipLong) ; |
| 459 | |
| 460 | /** |
| 461 | * @internal |
| 462 | */ |
| 463 | Horizon& eclipticToHorizon(Horizon& result, double eclipLong) ; |
| 464 | |
| 465 | //------------------------------------------------------------------------- |
| 466 | // The Sun |
| 467 | //------------------------------------------------------------------------- |
| 468 | |
| 469 | /** |
| 470 | * The longitude of the sun at the time specified by this object. |
| 471 | * The longitude is measured in radians along the ecliptic |
| 472 | * from the "first point of Aries," the point at which the ecliptic |
| 473 | * crosses the earth's equatorial plane at the vernal equinox. |
| 474 | * <p> |
| 475 | * Currently, this method uses an approximation of the two-body Kepler's |
| 476 | * equation for the earth and the sun. It does not take into account the |
| 477 | * perturbations caused by the other planets, the moon, etc. |
| 478 | * @internal |
| 479 | */ |
| 480 | double getSunLongitude(); |
| 481 | |
| 482 | /** |
| 483 | * TODO Make this public when the entire class is package-private. |
| 484 | */ |
| 485 | /*public*/ void getSunLongitude(double julianDay, double &longitude, double &meanAnomaly); |
| 486 | |
| 487 | /** |
| 488 | * The position of the sun at this object's current date and time, |
| 489 | * in equatorial coordinates. |
| 490 | * @param result fillin for the result |
| 491 | * @internal |
| 492 | */ |
| 493 | Equatorial& getSunPosition(Equatorial& result); |
| 494 | |
| 495 | public: |
| 496 | /** |
| 497 | * Constant representing the vernal equinox. |
| 498 | * For use with {@link #getSunTime getSunTime}. |
| 499 | * Note: In this case, "vernal" refers to the northern hemisphere's seasons. |
| 500 | * @internal |
| 501 | */ |
| 502 | // static double VERNAL_EQUINOX(); |
| 503 | |
| 504 | /** |
| 505 | * Constant representing the summer solstice. |
| 506 | * For use with {@link #getSunTime getSunTime}. |
| 507 | * Note: In this case, "summer" refers to the northern hemisphere's seasons. |
| 508 | * @internal |
| 509 | */ |
| 510 | static double SUMMER_SOLSTICE(); |
| 511 | |
| 512 | /** |
| 513 | * Constant representing the autumnal equinox. |
| 514 | * For use with {@link #getSunTime getSunTime}. |
| 515 | * Note: In this case, "autumn" refers to the northern hemisphere's seasons. |
| 516 | * @internal |
| 517 | */ |
| 518 | // static double AUTUMN_EQUINOX(); |
| 519 | |
| 520 | /** |
| 521 | * Constant representing the winter solstice. |
| 522 | * For use with {@link #getSunTime getSunTime}. |
| 523 | * Note: In this case, "winter" refers to the northern hemisphere's seasons. |
| 524 | * @internal |
| 525 | */ |
| 526 | static double WINTER_SOLSTICE(); |
| 527 | |
| 528 | /** |
| 529 | * Find the next time at which the sun's ecliptic longitude will have |
| 530 | * the desired value. |
| 531 | * @internal |
| 532 | */ |
| 533 | UDate getSunTime(double desired, UBool next); |
| 534 | |
| 535 | /** |
| 536 | * Returns the time (GMT) of sunrise or sunset on the local date to which |
| 537 | * this calendar is currently set. |
| 538 | * |
| 539 | * NOTE: This method only works well if this object is set to a |
| 540 | * time near local noon. Because of variations between the local |
| 541 | * official time zone and the geographic longitude, the |
| 542 | * computation can flop over into an adjacent day if this object |
| 543 | * is set to a time near local midnight. |
| 544 | * |
| 545 | * @internal |
| 546 | */ |
| 547 | UDate getSunRiseSet(UBool rise); |
| 548 | |
| 549 | //------------------------------------------------------------------------- |
| 550 | // The Moon |
| 551 | //------------------------------------------------------------------------- |
| 552 | |
| 553 | /** |
| 554 | * The position of the moon at the time set on this |
| 555 | * object, in equatorial coordinates. |
| 556 | * @internal |
| 557 | * @return const reference to internal field of calendar astronomer. Do not use outside of the lifetime of this astronomer. |
| 558 | */ |
| 559 | const Equatorial& getMoonPosition(); |
| 560 | |
| 561 | /** |
| 562 | * The "age" of the moon at the time specified in this object. |
| 563 | * This is really the angle between the |
| 564 | * current ecliptic longitudes of the sun and the moon, |
| 565 | * measured in radians. |
| 566 | * |
| 567 | * @see #getMoonPhase |
| 568 | * @internal |
| 569 | */ |
| 570 | double getMoonAge(); |
| 571 | |
| 572 | /** |
| 573 | * Calculate the phase of the moon at the time set in this object. |
| 574 | * The returned phase is a <code>double</code> in the range |
| 575 | * <code>0 <= phase < 1</code>, interpreted as follows: |
| 576 | * <ul> |
| 577 | * <li>0.00: New moon |
| 578 | * <li>0.25: First quarter |
| 579 | * <li>0.50: Full moon |
| 580 | * <li>0.75: Last quarter |
| 581 | * </ul> |
| 582 | * |
| 583 | * @see #getMoonAge |
| 584 | * @internal |
| 585 | */ |
| 586 | double getMoonPhase(); |
| 587 | |
| 588 | class U_I18N_API MoonAge : public UMemory { |
| 589 | public: |
| 590 | MoonAge(double l) |
| 591 | : value(l) { } |
| 592 | void set(double l) { value = l; } |
| 593 | double value; |
| 594 | }; |
| 595 | |
| 596 | /** |
| 597 | * Constant representing a new moon. |
| 598 | * For use with {@link #getMoonTime getMoonTime} |
| 599 | * @internal |
| 600 | */ |
| 601 | static const MoonAge NEW_MOON(); |
| 602 | |
| 603 | /** |
| 604 | * Constant representing the moon's first quarter. |
| 605 | * For use with {@link #getMoonTime getMoonTime} |
| 606 | * @internal |
| 607 | */ |
| 608 | // static const MoonAge FIRST_QUARTER(); |
| 609 | |
| 610 | /** |
| 611 | * Constant representing a full moon. |
| 612 | * For use with {@link #getMoonTime getMoonTime} |
| 613 | * @internal |
| 614 | */ |
| 615 | static const MoonAge FULL_MOON(); |
| 616 | |
| 617 | /** |
| 618 | * Constant representing the moon's last quarter. |
| 619 | * For use with {@link #getMoonTime getMoonTime} |
| 620 | * @internal |
| 621 | */ |
| 622 | // static const MoonAge LAST_QUARTER(); |
| 623 | |
| 624 | /** |
| 625 | * Find the next or previous time at which the Moon's ecliptic |
| 626 | * longitude will have the desired value. |
| 627 | * <p> |
| 628 | * @param desired The desired longitude. |
| 629 | * @param next <tt>true</tt> if the next occurrance of the phase |
| 630 | * is desired, <tt>false</tt> for the previous occurrance. |
| 631 | * @internal |
| 632 | */ |
| 633 | UDate getMoonTime(double desired, UBool next); |
| 634 | UDate getMoonTime(const MoonAge& desired, UBool next); |
| 635 | |
| 636 | /** |
| 637 | * Returns the time (GMT) of sunrise or sunset on the local date to which |
| 638 | * this calendar is currently set. |
| 639 | * @internal |
| 640 | */ |
| 641 | UDate getMoonRiseSet(UBool rise); |
| 642 | |
| 643 | //------------------------------------------------------------------------- |
| 644 | // Interpolation methods for finding the time at which a given event occurs |
| 645 | //------------------------------------------------------------------------- |
| 646 | |
| 647 | // private |
| 648 | class AngleFunc : public UMemory { |
| 649 | public: |
| 650 | virtual double eval(CalendarAstronomer&) = 0; |
| 651 | virtual ~AngleFunc(); |
| 652 | }; |
| 653 | friend class AngleFunc; |
| 654 | |
| 655 | UDate timeOfAngle(AngleFunc& func, double desired, |
| 656 | double periodDays, double epsilon, UBool next); |
| 657 | |
| 658 | class CoordFunc : public UMemory { |
| 659 | public: |
| 660 | virtual void eval(Equatorial& result, CalendarAstronomer&) = 0; |
| 661 | virtual ~CoordFunc(); |
| 662 | }; |
| 663 | friend class CoordFunc; |
| 664 | |
| 665 | double riseOrSet(CoordFunc& func, UBool rise, |
| 666 | double diameter, double refraction, |
| 667 | double epsilon); |
| 668 | |
| 669 | //------------------------------------------------------------------------- |
| 670 | // Other utility methods |
| 671 | //------------------------------------------------------------------------- |
| 672 | private: |
| 673 | |
| 674 | /** |
| 675 | * Return the obliquity of the ecliptic (the angle between the ecliptic |
| 676 | * and the earth's equator) at the current time. This varies due to |
| 677 | * the precession of the earth's axis. |
| 678 | * |
| 679 | * @return the obliquity of the ecliptic relative to the equator, |
| 680 | * measured in radians. |
| 681 | */ |
| 682 | double eclipticObliquity(); |
| 683 | |
| 684 | //------------------------------------------------------------------------- |
| 685 | // Private data |
| 686 | //------------------------------------------------------------------------- |
| 687 | private: |
| 688 | /** |
| 689 | * Current time in milliseconds since 1/1/1970 AD |
| 690 | * @see java.util.Date#getTime |
| 691 | */ |
| 692 | UDate fTime; |
| 693 | |
| 694 | /* These aren't used yet, but they'll be needed for sunset calculations |
| 695 | * and equatorial to horizon coordinate conversions |
| 696 | */ |
| 697 | double fLongitude; |
| 698 | double fLatitude; |
| 699 | double fGmtOffset; |
| 700 | |
| 701 | // |
| 702 | // The following fields are used to cache calculated results for improved |
| 703 | // performance. These values all depend on the current time setting |
| 704 | // of this object, so the clearCache method is provided. |
| 705 | // |
| 706 | |
| 707 | double julianDay; |
| 708 | double julianCentury; |
| 709 | double sunLongitude; |
| 710 | double meanAnomalySun; |
| 711 | double moonLongitude; |
| 712 | double moonEclipLong; |
| 713 | double meanAnomalyMoon; |
| 714 | double eclipObliquity; |
| 715 | double siderealT0; |
| 716 | double siderealTime; |
| 717 | |
| 718 | void clearCache(); |
| 719 | |
| 720 | Equatorial moonPosition; |
| 721 | UBool moonPositionSet; |
| 722 | |
| 723 | /** |
| 724 | * @internal |
| 725 | */ |
| 726 | // UDate local(UDate localMillis); |
| 727 | }; |
| 728 | |
| 729 | U_NAMESPACE_END |
| 730 | |
| 731 | struct UHashtable; |
| 732 | |
| 733 | U_NAMESPACE_BEGIN |
| 734 | |
| 735 | /** |
| 736 | * Cache of month -> julian day |
| 737 | * @internal |
| 738 | */ |
| 739 | class CalendarCache : public UMemory { |
| 740 | public: |
| 741 | static int32_t get(CalendarCache** cache, int32_t key, UErrorCode &status); |
| 742 | static void put(CalendarCache** cache, int32_t key, int32_t value, UErrorCode &status); |
| 743 | virtual ~CalendarCache(); |
| 744 | private: |
| 745 | CalendarCache(int32_t size, UErrorCode& status); |
| 746 | static void createCache(CalendarCache** cache, UErrorCode& status); |
| 747 | /** |
| 748 | * not implemented |
| 749 | */ |
| 750 | CalendarCache(); |
| 751 | UHashtable *fTable; |
| 752 | }; |
| 753 | |
| 754 | U_NAMESPACE_END |
| 755 | |
| 756 | #endif |
| 757 | #endif |