diff options
Diffstat (limited to 'src/libical/caldate.c')
| -rw-r--r-- | src/libical/caldate.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/src/libical/caldate.c b/src/libical/caldate.c index f3d600c2..a1de590e 100644 --- a/src/libical/caldate.c +++ b/src/libical/caldate.c @@ -1,4 +1,8 @@ /* + * This work is based on work from Hiram Clawson and has been modified to the + * needs of the libical project. The original copyright notice is as follows: + */ +/* * Copyright (c) 1986-2000, Hiram Clawson * All rights reserved. * @@ -33,6 +37,18 @@ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF * THE POSSIBILITY OF SUCH DAMAGE. */ +/* + * The modifications made are licensed as follows (to distinguish between + * the original code and the modifications made, refer to the source code + * history): + */ +/*====================================================================== + + SPDX-FileCopyrightText: 2018, Markus Minichmayr + https://tapkey.com + + SPDX-License-Identifier: LGPL-2.1-only OR MPL-2.0 + ========================================================================*/ #include "astime.h" /* time structures */ @@ -173,3 +189,89 @@ double juldat( struct ut_instant * date ) date->weekday = (jd + 1L) % 7L; return( date->j_date ); } /* end of double juldat( date ) */ + +void caldat_int( struct ut_instant_int * date ) +{ + long jd; + long ka; + long kb; + long kc; + long kd; + long ke; + long ialp; + + jd = (long) (date->j_date0 + 1L); /* integer julian date */ + ka = (long) jd; + if ( jd >= 2299161L ) + { + ialp = (long) (((jd * 100LL) - 186721625LL) / 3652425LL); + ka = jd + 1L + ialp - ( ialp >> 2 ); + } + kb = ka + 1524L; + kc = (long) ( ((kb * 100LL) - 12210LL) / 36525LL ); + kd = (long) ( ( kc * 36525LL ) / 100LL ); + ke = (long) ( (kb - kd) * 10000LL / 306001LL ); + date->day = kb - kd - ((long) ( (ke * 306001LL) / 10000LL )); + if ( ke > 13L ) + date->month = ke - 13L; + else + date->month = ke - 1L; + if ( (date->month == 2) && (date->day > 28) ) + date->day = 29; + if ( (date->month == 2) && (date->day == 29) && (ke == 3L) ) + date->year = kc - 4716L; + else if ( date->month > 2 ) + date->year = kc - 4716L; + else + date->year = kc - 4715L; + date->weekday = (jd + 1L) % 7L; /* day of week */ + if ( date->year == ((date->year >> 2) << 2) ) + date->day_of_year = + ( ( 275 * date->month ) / 9) + - ((date->month + 9) / 12) + + date->day - 30; + else + date->day_of_year = + ( ( 275 * date->month ) / 9) + - (((date->month + 9) / 12) << 1) + + date->day - 30; +} + +void juldat_int( struct ut_instant_int * date ) +{ + long iy0, im0; + long ia, ib; + long jd; + + /* conversion factors */ + if ( date->month <= 2 ) + { + iy0 = date->year - 1L; + im0 = date->month + 12; + } + else + { + iy0 = date->year; + im0 = date->month; + } + ia = iy0 / 100L; + ib = 2L - ia + (ia >> 2); + /* calculate julian date */ + if ( date->year < 0L ) + jd = (long) (((36525LL * iy0) - 75) / 100) + + (long) ((306001LL * (im0 + 1L)) / 10000) + + (long) date->day + 1720994L; + else + jd = (long) ((36525LL * iy0) / 100) + + (long) ((306001LL * (im0 + 1L)) / 10000) + + (long) date->day + 1720994L; + + /* on or after 15 October 1582 */ + if ((date->year > 1582) + || ((date->year == 1582) && (((date->month * 100) + date->day) >= 1015)) + ) { + jd += ib; + } + date->j_date0 = jd; + date->weekday = (jd + 2L) % 7L; +} /* end of void juldat( date ) */ |