xref: /PHP-8.1/ext/date/lib/astro.h (revision aae5907c)
1 /*
2  * The MIT License (MIT)
3  *
4  * Copyright (c) 2015-2019 Derick Rethans
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 
25 /* This macro computes the length of the day, from sunrise to sunset. */
26 /* Sunrise/set is considered to occur when the Sun's upper limb is    */
27 /* 35 arc minutes below the horizon (this accounts for the refraction */
28 /* of the Earth's atmosphere).                                        */
29 #define day_length(year,month,day,lon,lat)  \
30         __daylen__( year, month, day, lon, lat, -35.0/60.0, 1 )
31 
32 /* This macro computes the length of the day, including civil twilight. */
33 /* Civil twilight starts/ends when the Sun's center is 6 degrees below  */
34 /* the horizon.                                                         */
35 #define day_civil_twilight_length(year,month,day,lon,lat)  \
36         __daylen__( year, month, day, lon, lat, -6.0, 0 )
37 
38 /* This macro computes the length of the day, incl. nautical twilight.  */
39 /* Nautical twilight starts/ends when the Sun's center is 12 degrees    */
40 /* below the horizon.                                                   */
41 #define day_nautical_twilight_length(year,month,day,lon,lat)  \
42         __daylen__( year, month, day, lon, lat, -12.0, 0 )
43 
44 /* This macro computes the length of the day, incl. astronomical twilight. */
45 /* Astronomical twilight starts/ends when the Sun's center is 18 degrees   */
46 /* below the horizon.                                                      */
47 #define day_astronomical_twilight_length(year,month,day,lon,lat)  \
48         __daylen__( year, month, day, lon, lat, -18.0, 0 )
49 
50 
51 /* This macro computes times for sunrise/sunset.                      */
52 /* Sunrise/set is considered to occur when the Sun's upper limb is    */
53 /* 35 arc minutes below the horizon (this accounts for the refraction */
54 /* of the Earth's atmosphere).                                        */
55 #define timelib_astro_sun_rise_set(ts,lon,lat,hrise,hset,rise,set)  \
56         timelib_astro_rise_set_altitude( ts, lon, lat, -35.0/60.0, 1, hrise, hset, rise, set )
57 
58 /* This macro computes the start and end times of civil twilight.       */
59 /* Civil twilight starts/ends when the Sun's center is 6 degrees below  */
60 /* the horizon.                                                         */
61 #define civil_twilight(ts,lon,lat,start,end)  \
62         timelib_astro_rise_set_altitude( ts, lon, lat, -6.0, 0, start, end )
63 
64 /* This macro computes the start and end times of nautical twilight.    */
65 /* Nautical twilight starts/ends when the Sun's center is 12 degrees    */
66 /* below the horizon.                                                   */
67 #define nautical_twilight(ts,lon,lat,start,end)  \
68         timelib_astro_rise_set_altitude( ts, lon, lat, -12.0, 0, start, end )
69 
70 /* This macro computes the start and end times of astronomical twilight.   */
71 /* Astronomical twilight starts/ends when the Sun's center is 18 degrees   */
72 /* below the horizon.                                                      */
73 #define astronomical_twilight(ts,lon,lat,start,end)  \
74         timelib_astro_rise_set_altitude( ts, lon, lat, -18.0, 0, start, end )
75