plan9port

dist.c (3488B)

---

 #include "astro.h"
 
 double
 dist(Obj1 *p, Obj1 *q)
 {
 	double a;
 
 	a = sin(p->decl2)*sin(q->decl2) +
 		cos(p->decl2)*cos(q->decl2)*cos(p->ra-q->ra);
 	a = fabs(atan2(pyth(a), a)) / radsec;
 	return a;
 }
 
 int
 rline(int f)
 {
 	char *p;
 	int c;
 	static char buf[1024];
 	static int bc, bn, bf;
 
 	if(bf != f) {
 		bf = f;
 		bn = 0;
 	}
 	p = line;
 	do {
 		if(bn <= 0) {
 			bn = read(bf, buf, sizeof(buf));
 			if(bn <= 0)
 				return 1;
 			bc = 0;
 		}
 		c = buf[bc];
 		bn--; bc++;
 		*p++ = c;
 	} while(c != '\n');
 	return 0;
 }
 
 double
 sunel(double t)
 {
 	int i;
 
 	i = floor(t);
 	if(i < 0 || i > NPTS+1)
 		return -90;
 	t = osun.point[i].el +
 		(t-i)*(osun.point[i+1].el - osun.point[i].el);
 	return t;
 }
 
 double
 rise(Obj2 *op, double el)
 {
 	Obj2 *p;
 	int i;
 	double e1, e2;
 
 	e2 = 0;
 	p = op;
 	for(i=0; i<=NPTS; i++) {
 		e1 = e2;
 		e2 = p->point[i].el;
 		if(i >= 1 && e1 <= el && e2 > el)
 			goto found;
 	}
 	return -1;
 
 found:
 	return i - 1 + (el-e1)/(e2-e1);
 }
 
 double
 set(Obj2 *op, double el)
 {
 	Obj2 *p;
 	int i;
 	double e1, e2;
 
 	e2 = 0;
 	p = op;
 	for(i=0; i<=NPTS; i++) {
 		e1 = e2;
 		e2 = p->point[i].el;
 		if(i >= 1 && e1 > el && e2 <= el)
 			goto found;
 	}
 	return -1;
 
 found:
 	return i - 1 + (el-e1)/(e2-e1);
 }
 
 double
 solstice(int n)
 {
 	int i;
 	double d1, d2, d3;
 
 	d3 = (n*pi)/2 - pi;
 	if(n == 0)
 		d3 += pi;
 	d2 = 0.;
 	for(i=0; i<=NPTS; i++) {
 		d1 = d2;
 		d2 = osun.point[i].ra;
 		if(n == 0) {
 			d2 -= pi;
 			if(d2 < -pi)
 				d2 += pipi;
 		}
 		if(i >= 1 && d3 >= d1 && d3 < d2)
 			goto found;
 	}
 	return -1;
 
 found:
 	return i - (d3-d2)/(d1-d2);
 }
 
 double
 betcross(double b)
 {
 	int i;
 	double d1, d2;
 
 	d2 = 0;
 	for(i=0; i<=NPTS; i++) {
 		d1 = d2;
 		d2 = osun.point[i].mag;
 		if(i >= 1 && b >= d1 && b < d2)
 			goto found;
 	}
 	return -1;
 
 found:
 	return i - (b-d2)/(d1-d2);
 }
 
 double
 melong(Obj2 *op)
 {
 	Obj2 *p;
 	int i;
 	double d1, d2, d3;
 
 	d2 = 0;
 	d3 = 0;
 	p = op;
 	for(i=0; i<=NPTS; i++) {
 		d1 = d2;
 		d2 = d3;
 		d3 = dist(&p->point[i], &osun.point[i]);
 		if(i >= 2 && d2 >= d1 && d2 >= d3)
 			goto found;
 	}
 	return -1;
 
 found:
 	return i - 2;
 }
 
 #define	NEVENT	100
 Event	events[NEVENT];
 Event*	eventp = 0;
 
 void
 event(char *format, char *arg1, char *arg2, double tim, int flag)
 {
 	Event *p;
 
 	if(flag & DARK)
 		if(sunel(tim) > -12)
 			return;
 	if(flag & LIGHT)
 		if(sunel(tim) < 0)
 			return;
 	if(eventp == 0)
 		eventp = events;
 	p = eventp;
 	if(p >= events+NEVENT) {
 		fprint(2, "too many events\n");
 		return;
 	}
 	eventp++;
 	p->format = format;
 	p->arg1 = arg1;
 	p->arg2 = arg2;
 	p->tim = tim;
 	p->flag = flag;
 }
 
 int	evcomp(const void*, const void*);
 
 void
 evflush(void)
 {
 	Event *p;
 
 	if(eventp == 0)
 		return;
 	qsort(events, eventp-events, sizeof *p, evcomp);
 	for(p = events; p<eventp; p++) {
 		if((p->flag&SIGNIF) && flags['s'])
 			print("ding ding ding ");
 		print(p->format, p->arg1, p->arg2);
 		if(p->flag & PTIME)
 			ptime(day + p->tim*deld);
 		print("\n");
 	}
 	eventp = 0;
 }
 
 int
 evcomp(const void *a1, const void *a2)
 {
 	double t1, t2;
 	Event *p1, *p2;
 
 	p1 = (Event*)a1;
 	p2 = (Event*)a2;
 	t1 = p1->tim;
 	t2 = p2->tim;
 	if(p1->flag & SIGNIF)
 		t1 -= 1000.;
 	if(p2->flag & SIGNIF)
 		t2 -= 1000.;
 	if(t1 > t2)
 		return 1;
 	if(t2 > t1)
 		return -1;
 	return 0;
 }
 
 double
 pyth(double x)
 {
 
 	x *= x;
 	if(x > 1)
 		x = 1;
 	return sqrt(1-x);
 }
 
 char*
 skip(int n)
 {
 	int i;
 	char *cp;
 
 	cp = line;
 	for(i=0; i<n; i++) {
 		while(*cp == ' ' || *cp == '\t')
 			cp++;
 		while(*cp != '\n' && *cp != ' ' && *cp != '\t')
 			cp++;
 	}
 	while(*cp == ' ' || *cp == '\t')
 		cp++;
 	return cp;
 }