#include "ded.h"
#include "char.h"
#include "ter.h"

/************************************************************************
 *                                                                      *
 *                      copyright Richard Bornat 1981                   *
 *                                                                      *
 ************************************************************************/

/* make the screen cursor (real_c)
 * same as the user cursor (virt_c)
 */
fixpos()
 { register int srow, scol;

    if ( (srow=virt_c.row) <toprow) virt_c.row=srow=toprow;
    else
    if (srow>bottomrow) virt_c.row=srow=bottomrow;

    if ( (scol=virt_c.col) <leftcol) virt_c.col=scol=leftcol;
    else
    if (scol>rightcol) virt_c.col=scol=rightcol+1;

    move_to(srow, scol);
 }

/* adjust cursor position */
adj_virt_c(r,c)
register int r,c;
 {  register int i;

    if ((i = virt_c.row += r)<toprow) virt_c.row=toprow;
    else
    if (i > bottomrow) virt_c.row = bottomrow;

    if ((i = virt_c.col += c)<leftcol) virt_c.col = leftcol;
    else
    if (i > rightcol) virt_c.col = rightcol;
 }

/* set some arbitrary cursor */
void set_c(r,c,pos)
int r,c;
register struct CURSOR *pos;
 { pos->row = r; pos->col = c; }

/* move cursor with minimum of fuss - this procedure is called
 * by fixpos only when the cursor needs to be moved.
 */
move_to(srow, scol)
register int srow, scol;
 {  if (srow<0) srow = 0;
    else
    if (srow>FOOTROW) srow = FOOTROW;

    if (scol<0) scol = 0;
    else
    if (scol>RIGHTCOL) scol = RIGHTCOL;

    if (srow!=real_c.row || scol!=real_c.col)
     {  int n_vert, n_horiz;
	int ncr;
	register char *rp;

	n_vert = (srow>=real_c.row ?
			srow-real_c.row :
			ter.onechar.up!=0 ? real_c.row-srow : 500);
	n_horiz = (scol>=real_c.col ?
			scol-real_c.col :
			ter.onechar.left!=0 ? real_c.col-scol : 500);
	ncr = scol+1;

	/* use either incremental motion or cursor addressing -
	 * whichever uses less characters
	 */
	if ( (n_horiz<=ncr  ?
			n_vert+n_horiz<=ter.nmove :
			n_vert+ncr<=ter.nmove))
	 {  if (ncr<n_horiz)
	     { ttyout(c_CR); real_c.col = 0; }

	    /* vertical motion - move down */
	    while (srow>real_c.row)
	     { ttyout(c_NL); real_c.row++; }
	    /* move up */
	    while (srow<real_c.row)
	     { ttyout(ter.onechar.up); real_c.row--; }

	    /* horizontal motion - move right */
	    rp = rowmap[real_c.row]+real_c.col;
	    while (scol>real_c.col)
	     { ttyout(*rp++); real_c.col++; }
	    /* move left */
	    while (scol<real_c.col)
	     { ttyout(ter.onechar.left); real_c.col--; }
	 }
	else
	  (*ter.move)(real_c.row=srow, real_c.col=scol);
     }
 }