| 1 | #include "slalib.h"
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| 2 | #include "slamac.h"
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| 3 | void slaCalyd ( int iy, int im, int id, int *ny, int *nd, int *j )
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| 4 | /*
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| 5 | ** - - - - - - - - -
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| 6 | ** s l a C a l y d
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| 7 | ** - - - - - - - - -
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| 8 | **
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| 9 | ** Gregorian calendar date to year and day in year (in a Julian
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| 10 | ** calendar aligned to the 20th/21st century Gregorian calendar).
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| 11 | **
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| 12 | ** (Includes century default feature: use slaClyd for years
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| 13 | ** before 100AD.)
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| 14 | **
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| 15 | ** Given:
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| 16 | ** iy,im,id int year, month, day in Gregorian calendar
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| 17 | ** (year may optionally omit the century)
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| 18 | ** Returned:
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| 19 | ** *ny int year (re-aligned Julian calendar)
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| 20 | ** *nd int day in year (1 = January 1st)
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| 21 | ** *j int status:
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| 22 | ** 0 = OK
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| 23 | ** 1 = bad year (before -4711)
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| 24 | ** 2 = bad month
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| 25 | ** 3 = bad day (but conversion performed)
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| 26 | **
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| 27 | ** Notes:
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| 28 | **
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| 29 | ** 1 This routine exists to support the low-precision routines
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| 30 | ** slaEarth, slaMoon and slaEcor.
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| 31 | **
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| 32 | ** 2 Between 1900 March 1 and 2100 February 28 it returns answers
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| 33 | ** which are consistent with the ordinary Gregorian calendar.
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| 34 | ** Outside this range there will be a discrepancy which increases
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| 35 | ** by one day for every non-leap century year.
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| 36 | **
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| 37 | ** 3 Years in the range 50-99 are interpreted as 1950-1999, and
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| 38 | ** years in the range 00-49 are interpreted as 2000-2049.
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| 39 | **
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| 40 | ** Called: slaClyd
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| 41 | **
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| 42 | ** Last revision: 22 September 1995
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| 43 | **
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| 44 | ** Copyright P.T.Wallace. All rights reserved.
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| 45 | */
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| 46 | {
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| 47 | int i;
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| 48 |
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| 49 | /* Default century if appropriate */
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| 50 | if ( ( iy >= 0 ) && ( iy <= 49 ) )
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| 51 | i = iy + 2000;
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| 52 | else if ( ( iy >= 50 ) && ( iy <= 99 ) )
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| 53 | i = iy + 1900;
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| 54 | else
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| 55 | i = iy;
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| 56 |
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| 57 | /* Perform the conversion */
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| 58 | slaClyd ( i, im, id, ny, nd, j );
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| 59 | }
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