#include	"defs.h"

/*
 * Attach free end-points to the closest line endings.
 *
 * h = pointer to the 'w' entry
 */
gluepin(h)
	DL h;
{
	REG DL p, q, pe;
	INT d;

	chkhd(h, "w");
	p=h;
	while(p=nexta(h->type,p))
		if((p->type == 'p') &&
		    (q = findpt(h, p)) &&
		    (q->flag&(START|END)) &&
		    (another(h, 'e', q)!=nil(DL))) {
			d = xydist(p, q);
			pe=h;
			while(pe=nexta(h->type,pe)) {
				if((pe->type == 'p') && (pe != q) && (xydist(pe, q) < d))
					break;
			}
			if(pe==nil(DL)) {
				copypt(q, p);
				d = getdir(h, findpt(h, p));
				p->flag &= ~DIR;
				p->flag |= d;
			}
		}
}

/*
 * to label and/or number end-points
 *
 * head = 'w' header addr if known, else zero
 */
DL setpin(head)
	DL	head;
{
	REG DL	p, h;
	DL1	p1;
	ITEM	cv;
	STRING	tp;

	chkhd(head, "Mwc");
	rdname(cv, sizeof(cv));
	tp = commasep(cv);
	if (*cv == 0 && tp == 0)
		error("no pin name");
	if(*cv && number(cv)==0)
		error("not a number");
	while(cursor(p1)==SP){
		if( (h = findhead('w', p1)) && (p = findpt(h, p1))) {
			endpoint(h, p, tp, cv);
		}
		else
			error("wire end not found");
	}
	return(h);
}


/*
 * Create a new end-point or modify the existing end-point data.
 *
 * h = 'w' entry
 * p = position (may be existing 'p')
 * csig = signal name string (null string if keep the same)
 * cpin = pin number string (null if same)
 */
LOC endpoint(h, p, csig, cpin)
	REG DL h;
	DL p;
	STRING csig, cpin;
{
	REG DL q;
	REG INT flg;
	DL s;

	chkhd(h, "w");
	if(q = findxact('p', h, p)){
		if(*cpin == 0)
			cpin = q->tag;
		if (csig == 0)
			csig = q->tag + upbstr(q->tag) + 1;
		flg = q->flag&DIR;
		s = q;
	}
	else{
		s = findpt(h, p);
		flg = getdir(h, s);
		if (csig == 0)
			csig = "";
	}
	if(lastnum) flg=lastnum;
	showp(h, newdl(BEFORE, succ('w', h), 'p', flg, p, s->styl, cpin, csig));
	if(q)
		delete(q);
}

/*
 * Compute the direction of the end of the line closest to a given position.
 *
 * h = item header
 * p = wire 'e' entry
 * return = direction (0-3) of point closest to z; error if that point
 *          is not an endpoint
 */
LOC INT getdir(h, p)
	DL	h, p;
{
	REG DL	q;

	if(p->flag&START) {
		q = succ('e', p);
	}
	elif(p->flag&END) {
		REG DL	r=h;

		q = nil(DL);
		while(r=nexta('w', r)) {
			if(p==r)
				break;
			q=r;
		}
	}
	else{
		error("not an end point");
	}
	if(p->y == q->y)
		return((p->x > q->x) ? 0 : 2);
	else
		return((p->y > q->y) ? 1 : 3);
}