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Diffstat (limited to 'ast/erfa/dat.c')
| -rw-r--r-- | ast/erfa/dat.c | 306 |
1 files changed, 0 insertions, 306 deletions
diff --git a/ast/erfa/dat.c b/ast/erfa/dat.c deleted file mode 100644 index c3b1836..0000000 --- a/ast/erfa/dat.c +++ /dev/null @@ -1,306 +0,0 @@ -#include "erfa.h" - -int eraDat(int iy, int im, int id, double fd, double *deltat ) -/* -** - - - - - - - -** e r a D a t -** - - - - - - - -** -** For a given UTC date, calculate delta(AT) = TAI-UTC. -** -** :------------------------------------------: -** : : -** : IMPORTANT : -** : : -** : A new version of this function must be : -** : produced whenever a new leap second is : -** : announced. There are four items to : -** : change on each such occasion: : -** : : -** : 1) A new line must be added to the set : -** : of statements that initialize the : -** : array "changes". : -** : : -** : 2) The constant IYV must be set to the : -** : current year. : -** : : -** : 3) The "Latest leap second" comment : -** : below must be set to the new leap : -** : second date. : -** : : -** : 4) The "This revision" comment, later, : -** : must be set to the current date. : -** : : -** : Change (2) must also be carried out : -** : whenever the function is re-issued, : -** : even if no leap seconds have been : -** : added. : -** : : -** : Latest leap second: 2016 December 31 : -** : : -** :__________________________________________: -** -** Given: -** iy int UTC: year (Notes 1 and 2) -** im int month (Note 2) -** id int day (Notes 2 and 3) -** fd double fraction of day (Note 4) -** -** Returned: -** deltat double TAI minus UTC, seconds -** -** Returned (function value): -** int status (Note 5): -** 1 = dubious year (Note 1) -** 0 = OK -** -1 = bad year -** -2 = bad month -** -3 = bad day (Note 3) -** -4 = bad fraction (Note 4) -** -5 = internal error (Note 5) -** -** Notes: -** -** 1) UTC began at 1960 January 1.0 (JD 2436934.5) and it is improper -** to call the function with an earlier date. If this is attempted, -** zero is returned together with a warning status. -** -** Because leap seconds cannot, in principle, be predicted in -** advance, a reliable check for dates beyond the valid range is -** impossible. To guard against gross errors, a year five or more -** after the release year of the present function (see the constant -** IYV) is considered dubious. In this case a warning status is -** returned but the result is computed in the normal way. -** -** For both too-early and too-late years, the warning status is +1. -** This is distinct from the error status -1, which signifies a year -** so early that JD could not be computed. -** -** 2) If the specified date is for a day which ends with a leap second, -** the UTC-TAI value returned is for the period leading up to the -** leap second. If the date is for a day which begins as a leap -** second ends, the UTC-TAI returned is for the period following the -** leap second. -** -** 3) The day number must be in the normal calendar range, for example -** 1 through 30 for April. The "almanac" convention of allowing -** such dates as January 0 and December 32 is not supported in this -** function, in order to avoid confusion near leap seconds. -** -** 4) The fraction of day is used only for dates before the -** introduction of leap seconds, the first of which occurred at the -** end of 1971. It is tested for validity (0 to 1 is the valid -** range) even if not used; if invalid, zero is used and status -4 -** is returned. For many applications, setting fd to zero is -** acceptable; the resulting error is always less than 3 ms (and -** occurs only pre-1972). -** -** 5) The status value returned in the case where there are multiple -** errors refers to the first error detected. For example, if the -** month and day are 13 and 32 respectively, status -2 (bad month) -** will be returned. The "internal error" status refers to a -** case that is impossible but causes some compilers to issue a -** warning. -** -** 6) In cases where a valid result is not available, zero is returned. -** -** References: -** -** 1) For dates from 1961 January 1 onwards, the expressions from the -** file ftp://maia.usno.navy.mil/ser7/tai-utc.dat are used. -** -** 2) The 5ms timestep at 1961 January 1 is taken from 2.58.1 (p87) of -** the 1992 Explanatory Supplement. -** -** Called: -** eraCal2jd Gregorian calendar to JD -** -** Copyright (C) 2013-2016, NumFOCUS Foundation. -** Derived, with permission, from the SOFA library. See notes at end of file. -*/ -{ -/* Release year for this version of eraDat */ - enum { IYV = 2016}; - -/* Reference dates (MJD) and drift rates (s/day), pre leap seconds */ - static const double drift[][2] = { - { 37300.0, 0.0012960 }, - { 37300.0, 0.0012960 }, - { 37300.0, 0.0012960 }, - { 37665.0, 0.0011232 }, - { 37665.0, 0.0011232 }, - { 38761.0, 0.0012960 }, - { 38761.0, 0.0012960 }, - { 38761.0, 0.0012960 }, - { 38761.0, 0.0012960 }, - { 38761.0, 0.0012960 }, - { 38761.0, 0.0012960 }, - { 38761.0, 0.0012960 }, - { 39126.0, 0.0025920 }, - { 39126.0, 0.0025920 } - }; - -/* Number of Delta(AT) expressions before leap seconds were introduced */ - enum { NERA1 = (int) (sizeof drift / sizeof (double) / 2) }; - -/* Dates and Delta(AT)s */ - static const struct { - int iyear, month; - double delat; - } changes[] = { - { 1960, 1, 1.4178180 }, - { 1961, 1, 1.4228180 }, - { 1961, 8, 1.3728180 }, - { 1962, 1, 1.8458580 }, - { 1963, 11, 1.9458580 }, - { 1964, 1, 3.2401300 }, - { 1964, 4, 3.3401300 }, - { 1964, 9, 3.4401300 }, - { 1965, 1, 3.5401300 }, - { 1965, 3, 3.6401300 }, - { 1965, 7, 3.7401300 }, - { 1965, 9, 3.8401300 }, - { 1966, 1, 4.3131700 }, - { 1968, 2, 4.2131700 }, - { 1972, 1, 10.0 }, - { 1972, 7, 11.0 }, - { 1973, 1, 12.0 }, - { 1974, 1, 13.0 }, - { 1975, 1, 14.0 }, - { 1976, 1, 15.0 }, - { 1977, 1, 16.0 }, - { 1978, 1, 17.0 }, - { 1979, 1, 18.0 }, - { 1980, 1, 19.0 }, - { 1981, 7, 20.0 }, - { 1982, 7, 21.0 }, - { 1983, 7, 22.0 }, - { 1985, 7, 23.0 }, - { 1988, 1, 24.0 }, - { 1990, 1, 25.0 }, - { 1991, 1, 26.0 }, - { 1992, 7, 27.0 }, - { 1993, 7, 28.0 }, - { 1994, 7, 29.0 }, - { 1996, 1, 30.0 }, - { 1997, 7, 31.0 }, - { 1999, 1, 32.0 }, - { 2006, 1, 33.0 }, - { 2009, 1, 34.0 }, - { 2012, 7, 35.0 }, - { 2015, 7, 36.0 }, - { 2017, 1, 37.0 } - }; - -/* Number of Delta(AT) changes */ - enum { NDAT = (int) (sizeof changes / sizeof changes[0]) }; - -/* Miscellaneous local variables */ - int j, i, m; - double da, djm0, djm; - - -/* Initialize the result to zero. */ - *deltat = da = 0.0; - -/* If invalid fraction of a day, set error status and give up. */ - if (fd < 0.0 || fd > 1.0) return -4; - -/* Convert the date into an MJD. */ - j = eraCal2jd(iy, im, id, &djm0, &djm); - -/* If invalid year, month, or day, give up. */ - if (j < 0) return j; - -/* If pre-UTC year, set warning status and give up. */ - if (iy < changes[0].iyear) return 1; - -/* If suspiciously late year, set warning status but proceed. */ - if (iy > IYV + 5) j = 1; - -/* Combine year and month to form a date-ordered integer... */ - m = 12*iy + im; - -/* ...and use it to find the preceding table entry. */ - for (i = NDAT-1; i >=0; i--) { - if (m >= (12 * changes[i].iyear + changes[i].month)) break; - } - -/* Prevent underflow warnings. */ - if (i < 0) return -5; - -/* Get the Delta(AT). */ - da = changes[i].delat; - -/* If pre-1972, adjust for drift. */ - if (i < NERA1) da += (djm + fd - drift[i][0]) * drift[i][1]; - -/* Return the Delta(AT) value. */ - *deltat = da; - -/* Return the status. */ - return j; - -} -/*---------------------------------------------------------------------- -** -** -** Copyright (C) 2013-2016, NumFOCUS Foundation. -** All rights reserved. -** -** This library is derived, with permission, from the International -** Astronomical Union's "Standards of Fundamental Astronomy" library, -** available from http://www.iausofa.org. -** -** The ERFA version is intended to retain identical functionality to -** the SOFA library, but made distinct through different function and -** file names, as set out in the SOFA license conditions. The SOFA -** original has a role as a reference standard for the IAU and IERS, -** and consequently redistribution is permitted only in its unaltered -** state. The ERFA version is not subject to this restriction and -** therefore can be included in distributions which do not support the -** concept of "read only" software. -** -** Although the intent is to replicate the SOFA API (other than -** replacement of prefix names) and results (with the exception of -** bugs; any that are discovered will be fixed), SOFA is not -** responsible for any errors found in this version of the library. -** -** If you wish to acknowledge the SOFA heritage, please acknowledge -** that you are using a library derived from SOFA, rather than SOFA -** itself. -** -** -** TERMS AND CONDITIONS -** -** 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 Neither the name of the Standards Of Fundamental Astronomy Board, -** the International Astronomical Union 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 COPYRIGHT HOLDERS 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 -** COPYRIGHT HOLDER 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. -** -*/ |