tdist.c - plan9port - [fork] Plan 9 from user space
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tdist.c (3488B)
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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 }