#include <u.h>#include <libc.h>#include <libg.h>#include <frame.h> intfrdelete(Frame *f, ulong p0, ulong p1){	Point pt0, pt1, ppt0;	Frbox *b;	int n0, n1, n;	Rectangle r;	int nn0; 	if(p0>=f->nchars || p0==p1 || f->b==0)		return 0;	if(p1 > f->nchars)		p1 = f->nchars;	n0 = _frfindbox(f, 0, (unsigned long)0, p0);	n1 = _frfindbox(f, n0, p0, p1);	pt0 = _frptofcharnb(f, p0, n0);	pt1 = frptofchar(f, p1);	if(f->p0!=p0 || f->p1!=p1)	/* likely they ARE equal */		frselectp(f, F&~D);	/* can do better some day */	frselectf(f, pt0, pt1, 0);	if(n0 == f->nbox)		berror("off end in frdelete");	nn0 = n0;	ppt0 = pt0;	_frfreebox(f, n0, n1-1);	f->modified = 1; 	/*	 * Invariants:	 *  pt0 points to beginning, pt1 points to end	 *  n0 is box containing beginning of stuff being deleted	 *  n1, b are box containing beginning of stuff to be kept after deletion	 *  region between pt0 and pt1 is clear	 */	b = &f->box[n1];	while(pt1.x!=pt0.x && n1<f->nbox){		_frcklinewrap0(f, &pt0, b);		_frcklinewrap(f, &pt1, b);		if(b->nrune > 0){			n = _frcanfit(f, pt0, b);			if(n==0)				berror("_frcanfit==0");			if(n != b->nrune){				_frsplitbox(f, n1, n);				b = &f->box[n1];			}			r.min = pt1;			r.max = pt1;			r.max.x += b->wid;			r.max.y += f->font->height;			bitblt(f->b, pt0, f->b, r, S);			if(pt0.y == pt1.y)				r.min.x = r.max.x-(pt1.x-pt0.x);			bitblt(f->b, r.min, f->b, r, 0);		}		_fradvance(f, &pt1, b);		pt0.x += _frnewwid(f, pt0, b);		f->box[n0++] = f->box[n1++];		b++;	}	if(pt1.y != pt0.y){		Point pt2; 		pt2 = _frptofcharptb(f, 32767, pt1, n1);		if(pt2.y > f->r.max.y)			berror("frptofchar in frdelete");		if(n1 < f->nbox){			int q0, q1, q2; 			q0 = pt0.y+f->font->height;			q1 = pt1.y+f->font->height;			q2 = pt2.y+f->font->height;			bitblt(f->b, pt0, f->b, Rect(pt1.x, pt1.y, f->r.max.x, q1), S);			bitblt(f->b, Pt(f->r.min.x, q0), f->b, Rect(f->r.min.x, q1, f->r.max.x, q2), S);			frselectf(f, Pt(pt2.x, pt2.y-(pt1.y-pt0.y)), pt2, 0);		}else			frselectf(f, pt0, pt2, 0);	}	_frclosebox(f, n0, n1-1);	if(nn0>0 && f->box[nn0-1].nrune>=0 && ppt0.x-f->box[nn0-1].wid>=(int)f->left){		--nn0;		ppt0.x -= f->box[nn0].wid;	}	_frclean(f, ppt0, nn0, n0<f->nbox-1? n0+1 : n0);	if(f->p1 > p1)		f->p1 -= p1-p0;	else if(f->p1 > p0)		f->p1 = p0;	if(f->p0 > p1)		f->p0 -= p1-p0;	else if(f->p0 > p0)		f->p0 = p0;	frselectp(f, F&~D);	f->nchars -= p1-p0;	pt0 = frptofchar(f, f->nchars);	n = f->nlines;	f->nlines = (pt0.y-f->r.min.y)/f->font->height+(pt0.x>f->left);	return n - f->nlines;}