1 #include "astro.h"
2 
3 double
4 dist(Obj1 *p, Obj1 *q)
5 {
6 	double a;
7 
8 	a = sin(p->decl2)*sin(q->decl2) +
9 		cos(p->decl2)*cos(q->decl2)*cos(p->ra-q->ra);
10 	a = fabs(atan2(pyth(a), a)) / radsec;
11 	return a;
12 }
13 
14 int
15 rline(int f)
16 {
17 	char *p;
18 	int c;
19 	static char buf[1024];
20 	static int bc, bn, bf;
21 
22 	if(bf != f) {
23 		bf = f;
24 		bn = 0;
25 	}
26 	p = line;
27 	do {
28 		if(bn <= 0) {
29 			bn = read(bf, buf, sizeof(buf));
30 			if(bn <= 0)
31 				return 1;
32 			bc = 0;
33 		}
34 		c = buf[bc];
35 		bn--; bc++;
36 		*p++ = c;
37 	} while(c != '\n');
38 	return 0;
39 }
40 
41 double
42 sunel(double t)
43 {
44 	int i;
45 
46 	i = floor(t);
47 	if(i < 0 || i > NPTS+1)
48 		return -90;
49 	t = osun.point[i].el +
50 		(t-i)*(osun.point[i+1].el - osun.point[i].el);
51 	return t;
52 }
53 
54 double
55 rise(Obj2 *op, double el)
56 {
57 	Obj2 *p;
58 	int i;
59 	double e1, e2;
60 
61 	e2 = 0;
62 	p = op;
63 	for(i=0; i<=NPTS; i++) {
64 		e1 = e2;
65 		e2 = p->point[i].el;
66 		if(i >= 1 && e1 <= el && e2 > el)
67 			goto found;
68 	}
69 	return -1;
70 
71 found:
72 	return i - 1 + (el-e1)/(e2-e1);
73 }
74 
75 double
76 set(Obj2 *op, double el)
77 {
78 	Obj2 *p;
79 	int i;
80 	double e1, e2;
81 
82 	e2 = 0;
83 	p = op;
84 	for(i=0; i<=NPTS; i++) {
85 		e1 = e2;
86 		e2 = p->point[i].el;
87 		if(i >= 1 && e1 > el && e2 <= el)
88 			goto found;
89 	}
90 	return -1;
91 
92 found:
93 	return i - 1 + (el-e1)/(e2-e1);
94 }
95 
96 double
97 solstice(int n)
98 {
99 	int i;
100 	double d1, d2, d3;
101 
102 	d3 = (n*pi)/2 - pi;
103 	if(n == 0)
104 		d3 += pi;
105 	d2 = 0.;
106 	for(i=0; i<=NPTS; i++) {
107 		d1 = d2;
108 		d2 = osun.point[i].ra;
109 		if(n == 0) {
110 			d2 -= pi;
111 			if(d2 < -pi)
112 				d2 += pipi;
113 		}
114 		if(i >= 1 && d3 >= d1 && d3 < d2)
115 			goto found;
116 	}
117 	return -1;
118 
119 found:
120 	return i - (d3-d2)/(d1-d2);
121 }
122 
123 double
124 betcross(double b)
125 {
126 	int i;
127 	double d1, d2;
128 
129 	d2 = 0;
130 	for(i=0; i<=NPTS; i++) {
131 		d1 = d2;
132 		d2 = osun.point[i].mag;
133 		if(i >= 1 && b >= d1 && b < d2)
134 			goto found;
135 	}
136 	return -1;
137 
138 found:
139 	return i - (b-d2)/(d1-d2);
140 }
141 
142 double
143 melong(Obj2 *op)
144 {
145 	Obj2 *p;
146 	int i;
147 	double d1, d2, d3;
148 
149 	d2 = 0;
150 	d3 = 0;
151 	p = op;
152 	for(i=0; i<=NPTS; i++) {
153 		d1 = d2;
154 		d2 = d3;
155 		d3 = dist(&p->point[i], &osun.point[i]);
156 		if(i >= 2 && d2 >= d1 && d2 >= d3)
157 			goto found;
158 	}
159 	return -1;
160 
161 found:
162 	return i - 2;
163 }
164 
165 #define	NEVENT	100
166 Event	events[NEVENT];
167 Event*	eventp = 0;
168 
169 void
170 event(char *format, char *arg1, char *arg2, double tim, int flag)
171 {
172 	Event *p;
173 
174 	if(flag & DARK)
175 		if(sunel(tim) > -12)
176 			return;
177 	if(flag & LIGHT)
178 		if(sunel(tim) < 0)
179 			return;
180 	if(eventp == 0)
181 		eventp = events;
182 	p = eventp;
183 	if(p >= events+NEVENT) {
184 		fprint(2, "too many events\n");
185 		return;
186 	}
187 	eventp++;
188 	p->format = format;
189 	p->arg1 = arg1;
190 	p->arg2 = arg2;
191 	p->tim = tim;
192 	p->flag = flag;
193 }
194 
195 int	evcomp(const void*, const void*);
196 
197 void
198 evflush(void)
199 {
200 	Event *p;
201 
202 	if(eventp == 0)
203 		return;
204 	qsort(events, eventp-events, sizeof *p, evcomp);
205 	for(p = events; p<eventp; p++) {
206 		if((p->flag&SIGNIF) && flags['s'])
207 			print("ding ding ding ");
208 		print(p->format, p->arg1, p->arg2);
209 		if(p->flag & PTIME)
210 			ptime(day + p->tim*deld);
211 		print("\n");
212 	}
213 	eventp = 0;
214 }
215 
216 int
217 evcomp(const void *a1, const void *a2)
218 {
219 	double t1, t2;
220 	Event *p1, *p2;
221 
222 	p1 = (Event*)a1;
223 	p2 = (Event*)a2;
224 	t1 = p1->tim;
225 	t2 = p2->tim;
226 	if(p1->flag & SIGNIF)
227 		t1 -= 1000.;
228 	if(p2->flag & SIGNIF)
229 		t2 -= 1000.;
230 	if(t1 > t2)
231 		return 1;
232 	if(t2 > t1)
233 		return -1;
234 	return 0;
235 }
236 
237 double
238 pyth(double x)
239 {
240 
241 	x *= x;
242 	if(x > 1)
243 		x = 1;
244 	return sqrt(1-x);
245 }
246 
247 char*
248 skip(int n)
249 {
250 	int i;
251 	char *cp;
252 
253 	cp = line;
254 	for(i=0; i<n; i++) {
255 		while(*cp == ' ' || *cp == '\t')
256 			cp++;
257 		while(*cp != '\n' && *cp != ' ' && *cp != '\t')
258 			cp++;
259 	}
260 	while(*cp == ' ' || *cp == '\t')
261 		cp++;
262 	return cp;
263 }