/*	DISPLAY.C
 *
 * The functions in this file handle redisplay. There are two halves, the
 * ones that update the virtual display screen, and the ones that make the
 * physical display screen the same as the virtual display screen. These
 * functions use hints that are left in the windows by the commands.
 *
 *	modified by Petri Kutvonen
 */

#include	<errno.h>
#include        <stdio.h>
#include	"estruct.h"
#include        "edef.h"

typedef struct  VIDEO {
        int	v_flag;                 /* Flags */
#if	COLOR
	int	v_fcolor;		/* current forground color */
	int	v_bcolor;		/* current background color */
	int	v_rfcolor;		/* requested forground color */
	int	v_rbcolor;		/* requested background color */
#endif
        char    v_text[1];              /* Screen data. */
}       VIDEO;

#define VFCHG   0x0001                  /* Changed flag			*/
#define	VFEXT	0x0002			/* extended (beyond column 80)	*/
#define	VFREV	0x0004			/* reverse video status		*/
#define	VFREQ	0x0008			/* reverse video request	*/
#define	VFCOL	0x0010			/* color change requested	*/

VIDEO   **vscreen;                      /* Virtual screen. */
#if	MEMMAP == 0 || SCROLLCODE
VIDEO   **pscreen;                      /* Physical screen. */
#endif

int displaying = TRUE;
#if UNIX
#include <signal.h>
#endif
#ifdef SIGWINCH
#include <sys/ioctl.h>
/* for window size changes */
int chg_width, chg_height;
#endif

/*
 * Initialize the data structures used by the display code. The edge vectors
 * used to access the screens are set up. The operating system's terminal I/O
 * channel is set up. All the other things get initialized at compile time.
 * The original window has "WFCHG" set, so that it will get completely
 * redrawn on the first call to "update".
 */
vtinit()
{
    register int i;
    register VIDEO *vp;
    char *malloc();

    TTopen();		/* open the screen */
    TTkopen();		/* open the keyboard */
    TTrev(FALSE);
    vscreen = (VIDEO **) malloc(term.t_mrow*sizeof(VIDEO *));

    if (vscreen == NULL)
        exit(1);

#if	MEMMAP == 0 || SCROLLCODE
    pscreen = (VIDEO **) malloc(term.t_mrow*sizeof(VIDEO *));

    if (pscreen == NULL)
        exit(1);
#endif

    for (i = 0; i < term.t_mrow; ++i)
        {
        vp = (VIDEO *) malloc(sizeof(VIDEO)+term.t_mcol);

        if (vp == NULL)
            exit(1);

	vp->v_flag = 0;
#if	COLOR
	vp->v_rfcolor = 7;
	vp->v_rbcolor = 0;
#endif
        vscreen[i] = vp;
#if	MEMMAP == 0 || SCROLLCODE
        vp = (VIDEO *) malloc(sizeof(VIDEO)+term.t_mcol);

        if (vp == NULL)
            exit(1);

	vp->v_flag = 0;
        pscreen[i] = vp;
#endif
        }
}

#if	CLEAN
/* free up all the dynamically allocated video structures */

vtfree()
{
	int i;
	for (i = 0; i < term.t_mrow; ++i) {
		free(vscreen[i]);
#if	MEMMAP == 0 || SCROLLCODE
		free(pscreen[i]);
#endif
	}
	free(vscreen);
#if	MEMMAP == 0 || SCROLLCODE
	free(pscreen);
#endif
}
#endif

/*
 * Clean up the virtual terminal system, in anticipation for a return to the
 * operating system. Move down to the last line and clear it out (the next
 * system prompt will be written in the line). Shut down the channel to the
 * terminal.
 */
vttidy()
{
    mlerase();
    movecursor(term.t_nrow, 0);
    TTflush();
    TTclose();
    TTkclose();
#ifdef PKCODE
    write(1, "\r", 1);
#endif
}

/*
 * Set the virtual cursor to the specified row and column on the virtual
 * screen. There is no checking for nonsense values; this might be a good
 * idea during the early stages.
 */
vtmove(row, col)
{
    vtrow = row;
    vtcol = col;
}

/* Write a character to the virtual screen. The virtual row and
   column are updated. If we are not yet on left edge, don't print
   it yet. If the line is too long put a "$" in the last column.
   This routine only puts printing characters into the virtual
   terminal buffers. Only column overflow is checked.
*/

vtputc(c)

int c;

{
	register VIDEO *vp;	/* ptr to line being updated */

	vp = vscreen[vtrow];

	if (vtcol >= term.t_ncol) {
		++vtcol;
		vp->v_text[term.t_ncol - 1] = '$';
	} else if (c < 0x20 || c == 0x7F) {
		if (c == '\t') {
			do {
				vtputc(' ');
			} while (((vtcol + taboff)&tabmask) != 0);
		} else {
			vtputc('^');
			vtputc(c ^ 0x40);
		}
	} else {
		if (vtcol >= 0)
			vp->v_text[vtcol] = c;
		++vtcol;
	}
}

/*
 * Erase from the end of the software cursor to the end of the line on which
 * the software cursor is located.
 */
vteeol()
{
/*  register VIDEO      *vp;	*/
    register char	*vcp = vscreen[vtrow]->v_text;

/*  vp = vscreen[vtrow];	*/
    while (vtcol < term.t_ncol)
/*	vp->v_text[vtcol++] = ' ';	*/
	vcp[vtcol++] = ' ';
}

/* upscreen:	user routine to force a screen update
		always finishes complete update		*/

upscreen(f, n)

{
	update(TRUE);
	return(TRUE);
}

#if SCROLLCODE
int scrflags;
#endif

/*
 * Make sure that the display is right. This is a three part process. First,
 * scan through all of the windows looking for dirty ones. Check the framing,
 * and refresh the screen. Second, make sure that "currow" and "curcol" are
 * correct for the current window. Third, make the virtual and physical
 * screens the same.
 */
update(force)

int force;	/* force update past type ahead? */

{
	register WINDOW *wp;

#if	TYPEAH && ! PKCODE
	if (force == FALSE && typahead())
		return(TRUE);
#endif
#if	VISMAC == 0
	if (force == FALSE && kbdmode == PLAY)
		return(TRUE);
#endif

        displaying = TRUE;

#if SCROLLCODE

        /* first, propagate mode line changes to all instances of
                a buffer displayed in more than one window */
        wp = wheadp;
        while (wp != NULL) {
                if (wp->w_flag & WFMODE) {
                        if (wp->w_bufp->b_nwnd > 1) {
                                /* make sure all previous windows have this */
                                register WINDOW *owp;
                                owp = wheadp;
                                while (owp != NULL) {
                                        if (owp->w_bufp == wp->w_bufp)
                                                owp->w_flag |= WFMODE;
                                        owp = owp->w_wndp;
                                }
                        }
                }
                wp = wp->w_wndp;
        }

#endif

	/* update any windows that need refreshing */
	wp = wheadp;
	while (wp != NULL) {
		if (wp->w_flag) {
			/* if the window has changed, service it */
			reframe(wp);	/* check the framing */
#if SCROLLCODE
                        if (wp->w_flag & (WFKILLS|WFINS)) {
                                scrflags |= (wp->w_flag & (WFINS|WFKILLS));
                                wp->w_flag &= ~(WFKILLS|WFINS);
                        }
#endif
			if ((wp->w_flag & ~WFMODE) == WFEDIT)
				updone(wp);	/* update EDITed line */
			else if (wp->w_flag & ~WFMOVE)
				updall(wp);	/* update all lines */
#if SCROLLCODE
                        if (scrflags || (wp->w_flag & WFMODE))
#else
			if (wp->w_flag & WFMODE)
#endif
				modeline(wp);	/* update modeline */
			wp->w_flag = 0;
			wp->w_force = 0;
		}
		/* on to the next window */
		wp = wp->w_wndp;
	}

	/* recalc the current hardware cursor location */
	updpos();

#if	MEMMAP && ! SCROLLCODE
	/* update the cursor and flush the buffers */
	movecursor(currow, curcol - lbound);
#endif

	/* check for lines to de-extend */
	upddex();

	/* if screen is garbage, re-plot it */
	if (sgarbf != FALSE)
		updgar();

	/* update the virtual screen to the physical screen */
	updupd(force);

	/* update the cursor and flush the buffers */
	movecursor(currow, curcol - lbound);
	TTflush();
        displaying = FALSE;
#if SIGWINCH
        while (chg_width || chg_height)
                newscreensize(chg_height,chg_width);
#endif
	return(TRUE);
}

/*	reframe:	check to see if the cursor is on in the window
			and re-frame it if needed or wanted		*/

reframe(wp)

WINDOW *wp;

{
	register LINE *lp, *lp0;
	register int i;

	/* if not a requested reframe, check for a needed one */
	if ((wp->w_flag & WFFORCE) == 0) {
#if SCROLLCODE
                /* loop from one line above the window to one line after */
                lp = wp->w_linep;
                lp0 = lback(lp);
                if (lp0 == wp->w_bufp->b_linep)
                	i = 0;
                else {
                	i = -1;
                	lp = lp0;
                }
                for (; i <= (int)(wp->w_ntrows); i++)
#else
		lp = wp->w_linep;
		for (i = 0; i < wp->w_ntrows; i++)
#endif
		{
			/* if the line is in the window, no reframe */
			if (lp == wp->w_dotp) {
#if SCROLLCODE
                                /* if not _quite_ in, we'll reframe gently */
                                if ( i < 0 || i == wp->w_ntrows) {
                                        /* if the terminal can't help, then
                                                we're simply outside */
                                        if (term.t_scroll == NULL)
						i = wp->w_force;
					break;
                                }
#endif
				return(TRUE);
			}

			/* if we are at the end of the file, reframe */
			if (lp == wp->w_bufp->b_linep)
				break;

			/* on to the next line */
			lp = lforw(lp);
		}
	}

#if SCROLLCODE
        if (i == -1) {  /* we're just above the window */
		i = scrollcount;  /* put dot at first line */
                scrflags |= WFINS;
        } else if (i == wp->w_ntrows) { /* we're just below the window */
		i = -scrollcount; /* put dot at last line */
                scrflags |= WFKILLS;
        } else /* put dot where requested */
#endif
                i = wp->w_force;  /* (is 0, unless reposition() was called) */

        wp->w_flag |= WFMODE;

	/* how far back to reframe? */
	if (i > 0) {		/* only one screen worth of lines max */
		if (--i >= wp->w_ntrows)
			i = wp->w_ntrows - 1;
	} else if (i < 0) {	/* negative update???? */
		i += wp->w_ntrows;
		if (i < 0)
			i = 0;
	} else
		i = wp->w_ntrows / 2;

	/* backup to new line at top of window */
	lp = wp->w_dotp;
	while (i != 0 && lback(lp) != wp->w_bufp->b_linep) {
		--i;
		lp = lback(lp);
	}

	/* and reset the current line at top of window */
	wp->w_linep = lp;
	wp->w_flag |= WFHARD;
	wp->w_flag &= ~WFFORCE;
	return(TRUE);
}

/*	updone:	update the current line	to the virtual screen		*/

updone(wp)

WINDOW *wp;	/* window to update current line in */

{
	register LINE *lp;	/* line to update */
	register int sline;	/* physical screen line to update */
	register int i;

	/* search down the line we want */
	lp = wp->w_linep;
	sline = wp->w_toprow;
	while (lp != wp->w_dotp) {
		++sline;
		lp = lforw(lp);
	}

	/* and update the virtual line */
	vscreen[sline]->v_flag |= VFCHG;
	vscreen[sline]->v_flag &= ~VFREQ;
	vtmove(sline, 0);
	for (i=0; i < llength(lp); ++i)
		vtputc(lgetc(lp, i));
#if	COLOR
	vscreen[sline]->v_rfcolor = wp->w_fcolor;
	vscreen[sline]->v_rbcolor = wp->w_bcolor;
#endif
	vteeol();
}

/*	updall:	update all the lines in a window on the virtual screen */

updall(wp)

WINDOW *wp;	/* window to update lines in */

{
	register LINE *lp;	/* line to update */
	register int sline;	/* physical screen line to update */
	register int i;

	/* search down the lines, updating them */
	lp = wp->w_linep;
	sline = wp->w_toprow;
	while (sline < wp->w_toprow + wp->w_ntrows) {

		/* and update the virtual line */
		vscreen[sline]->v_flag |= VFCHG;
		vscreen[sline]->v_flag &= ~VFREQ;
		vtmove(sline, 0);
		if (lp != wp->w_bufp->b_linep) {
			/* if we are not at the end */
			for (i=0; i < llength(lp); ++i)
				vtputc(lgetc(lp, i));
			lp = lforw(lp);
		}

		/* on to the next one */
#if	COLOR
		vscreen[sline]->v_rfcolor = wp->w_fcolor;
		vscreen[sline]->v_rbcolor = wp->w_bcolor;
#endif
		vteeol();
		++sline;
	}

}

/*	updpos:	update the position of the hardware cursor and handle extended
		lines. This is the only update for simple moves.	*/

updpos()

{
	register LINE *lp;
	register int c;
	register int i;

	/* find the current row */
	lp = curwp->w_linep;
	currow = curwp->w_toprow;
	while (lp != curwp->w_dotp) {
		++currow;
		lp = lforw(lp);
	}

	/* find the current column */
	curcol = 0;
	i = 0;
	while (i < curwp->w_doto) {
		c = lgetc(lp, i++);
		if (c == '\t')
			curcol |= tabmask;
		else
			if (c < 0x20 || c == 0x7f)
				++curcol;

		++curcol;
	}

	/* if extended, flag so and update the virtual line image */
	if (curcol >=  term.t_ncol - 1) {
		vscreen[currow]->v_flag |= (VFEXT | VFCHG);
		updext();
	} else
		lbound = 0;
}

/*	upddex:	de-extend any line that derserves it		*/

upddex()

{
	register WINDOW *wp;
	register LINE *lp;
	register int i,j;

	wp = wheadp;

	while (wp != NULL) {
		lp = wp->w_linep;
		i = wp->w_toprow;

		while (i < wp->w_toprow + wp->w_ntrows) {
			if (vscreen[i]->v_flag & VFEXT) {
				if ((wp != curwp) || (lp != wp->w_dotp) ||
				   (curcol < term.t_ncol - 1)) {
					vtmove(i, 0);
					for (j = 0; j < llength(lp); ++j)
						vtputc(lgetc(lp, j));
					vteeol();

					/* this line no longer is extended */
					vscreen[i]->v_flag &= ~VFEXT;
					vscreen[i]->v_flag |= VFCHG;
				}
			}
			lp = lforw(lp);
			++i;
		}
		/* and onward to the next window */
		wp = wp->w_wndp;
	}
}

/*	updgar:	if the screen is garbage, clear the physical screen and
		the virtual screen and force a full update		*/

updgar()

{
	register char *txt;
	register int i,j;

	for (i = 0; i < term.t_nrow; ++i) {
		vscreen[i]->v_flag |= VFCHG;
#if	REVSTA
		vscreen[i]->v_flag &= ~VFREV;
#endif
#if	COLOR
		vscreen[i]->v_fcolor = gfcolor;
		vscreen[i]->v_bcolor = gbcolor;
#endif
#if	MEMMAP == 0 || SCROLLCODE
		txt = pscreen[i]->v_text;
		for (j = 0; j < term.t_ncol; ++j)
			txt[j] = ' ';
#endif
	}

	movecursor(0, 0);		 /* Erase the screen. */
	(*term.t_eeop)();
	sgarbf = FALSE;			 /* Erase-page clears */
	mpresf = FALSE;			 /* the message area. */
#if	COLOR
	mlerase();			/* needs to be cleared if colored */
#endif
}

/*	updupd:	update the physical screen from the virtual screen	*/

updupd(force)

int force;	/* forced update flag */

{
	register VIDEO *vp1;
	register int i;

#if SCROLLCODE
        if (scrflags & WFKILLS)
                scrolls(FALSE);
        if (scrflags & WFINS)
                scrolls(TRUE);
        scrflags = 0;
#endif

	for (i = 0; i < term.t_nrow; ++i) {
		vp1 = vscreen[i];

		/* for each line that needs to be updated*/
		if ((vp1->v_flag & VFCHG) != 0) {
#if	TYPEAH && ! PKCODE
			if (force == FALSE && typahead())
				return(TRUE);
#endif
#if	MEMMAP && ! SCROLLCODE
			updateline(i, vp1);
#else
			updateline(i, vp1, pscreen[i]);
#endif
		}
	}
	return(TRUE);
}

#if SCROLLCODE

/* optimize out scrolls (line breaks, and newlines) */
/* arg. chooses between looking for inserts or deletes */
int
scrolls(inserts)	/* returns true if it does something */
{
	struct	VIDEO *vpv ;	/* virtual screen image */
	struct	VIDEO *vpp ;	/* physical screen image */
	int	i, j, k ;
	int	rows, cols ;
	int	first, match, count, ptarget, vtarget, end ;
	int	longmatch, longcount;
	int	from, to;

	if (!term.t_scroll) /* no way to scroll */
		return FALSE;

	rows = term.t_nrow ;
	cols = term.t_ncol ;

	first = -1 ;
	for (i = 0; i < rows; i++) {	/* find first wrong line */
		if (!texttest(i,i)) {
			first = i;
			break;
		}
	}

	if (first < 0)
		return FALSE;		/* no text changes */

	vpv = vscreen[first] ;
	vpp = pscreen[first] ;

	if (inserts) {
		/* determine types of potential scrolls */
		end = endofline(vpv->v_text,cols) ;
		if ( end == 0 )
			ptarget = first ;		/* newlines */
		else if ( strncmp(vpp->v_text, vpv->v_text, end) == 0 )
			ptarget = first + 1 ;	/* broken line newlines */
		else
			ptarget = first ;
	} else {
		vtarget = first + 1 ;
	}

	/* find the matching shifted area */
	match = -1 ;
	longmatch = -1;
	longcount = 0;
	from = inserts ? ptarget : vtarget;
	for (i = from+1; i < rows-longcount /* P.K. */; i++) {
		if (inserts ? texttest(i,from) : texttest(from,i) ) {
			match = i ;
			count = 1 ;
			for (j=match+1, k=from+1; j<rows && k<rows; j++, k++) {
				if (inserts ? texttest(j,k) : texttest(k,j))
					count++ ;
				else
					break ;
			}
			if (longcount < count) {
				longcount = count;
				longmatch = match;
			}
		}
	}
	match = longmatch;
	count = longcount;

	if (!inserts) {
		/* full kill case? */
		if (match > 0 && texttest(first, match-1)) {
			vtarget-- ;
			match-- ;
			count++ ;
		}
	}

	/* do the scroll */
	if (match>0 && count>2) {		 /* got a scroll */
		/* move the count lines starting at ptarget to match */
		if (inserts) {
			from = ptarget;
			to = match;
		} else {
			from = match;
			to = vtarget;
		}
#if 0
		{
			char line[NLINE];
			sprintf(line,
				"scrolls: move the %d lines starting at %d to %d, first %d, scrolls %d",
				count,from,to,first, 2*count >= abs(from-to));
			mlwrite(line);
		}	
#endif		
		if (2*count < abs(from-to))
			return(FALSE);
		scrscroll(from, to, count) ;
		for (i = 0; i < count; i++) {
			vpp = pscreen[to+i] ;
			vpv = vscreen[to+i];
			strncpy(vpp->v_text, vpv->v_text, cols) ;
			vpp->v_flag = vpv->v_flag; 	/* XXX */
			if (vpp->v_flag & VFREV) {
				vpp->v_flag &= ~VFREV;
				vpp->v_flag |= ~VFREQ;
			}
#if	MEMMAP
			vscreen[to+i]->v_flag &= ~VFCHG;
#endif
		}
		if (inserts) {
			from = ptarget;
			to = match;
		} else {
			from = vtarget+count;
			to = match+count;
		}
#if	MEMMAP == 0
		for (i = from; i < to; i++) {
			char *txt;
			txt = pscreen[i]->v_text;
			for (j = 0; j < term.t_ncol; ++j)
				txt[j] = ' ';
			vscreen[i]->v_flag |= VFCHG;
		}
#endif
		return(TRUE) ;
	}
	return(FALSE) ;
}

/* move the "count" lines starting at "from" to "to" */
scrscroll(from, to, count)
{
	ttrow = ttcol = -1;
	(*term.t_scroll)(from,to,count);
}

texttest(vrow,prow)		/* return TRUE on text match */
int	vrow, prow ;		/* virtual, physical rows */
{
struct	VIDEO *vpv = vscreen[vrow] ;	/* virtual screen image */
struct	VIDEO *vpp = pscreen[prow]  ;	/* physical screen image */

	return (!memcmp(vpv->v_text, vpp->v_text, term.t_ncol)) ;
}

/* return the index of the first blank of trailing whitespace */
int
endofline(s,n)
char 	*s ;
{
int	i ;
	for (i = n - 1; i >= 0; i--)
		if (s[i] != ' ') return(i+1) ;
	return(0) ;
}

#endif /* SCROLLCODE */

/*	updext: update the extended line which the cursor is currently
		on at a column greater than the terminal width. The line
		will be scrolled right or left to let the user see where
		the cursor is
								*/

updext()

{
	register int rcursor;	/* real cursor location */
	register LINE *lp;	/* pointer to current line */
	register int j;		/* index into line */

	/* calculate what column the real cursor will end up in */
	rcursor = ((curcol - term.t_ncol) % term.t_scrsiz) + term.t_margin;
	taboff = lbound = curcol - rcursor + 1;

	/* scan through the line outputing characters to the virtual screen */
	/* once we reach the left edge					*/
	vtmove(currow, -lbound);	/* start scanning offscreen */
	lp = curwp->w_dotp;		/* line to output */
	for (j=0; j<llength(lp); ++j)	/* until the end-of-line */
		vtputc(lgetc(lp, j));

	/* truncate the virtual line, restore tab offset */
	vteeol();
	taboff = 0;

	/* and put a '$' in column 1 */
	vscreen[currow]->v_text[0] = '$';
}

/*
 * Update a single line. This does not know how to use insert or delete
 * character sequences; we are using VT52 functionality. Update the physical
 * row and column variables. It does try an exploit erase to end of line. The
 * RAINBOW version of this routine uses fast video.
 */
#if	MEMMAP
/*	UPDATELINE specific code for the IBM-PC and other compatables */

updateline(row, vp1
#if	SCROLLCODE
		   , vp2
#endif
)

int row;		/* row of screen to update */
struct VIDEO *vp1;	/* virtual screen image */

#if	SCROLLCODE
struct VIDEO *vp2;
#endif
{
#if	SCROLLCODE
	register char *cp1;
	register char *cp2;
	register int nch;

	cp1 = &vp1->v_text[0];
	cp2 = &vp2->v_text[0];
	nch = term.t_ncol;
	do
        {
		*cp2 = *cp1;
		++cp2;
		++cp1;
        }
	while (--nch);
#endif
#if	COLOR
	scwrite(row, vp1->v_text, vp1->v_rfcolor, vp1->v_rbcolor);
	vp1->v_fcolor = vp1->v_rfcolor;
	vp1->v_bcolor = vp1->v_rbcolor;
#else
	if (vp1->v_flag & VFREQ)
		scwrite(row, vp1->v_text, 0, 7);
	else
		scwrite(row, vp1->v_text, 7, 0);
#endif
	vp1->v_flag &= ~(VFCHG | VFCOL);	/* flag this line as changed */

}

#else

updateline(row, vp1, vp2)

int row;		/* row of screen to update */
struct VIDEO *vp1;	/* virtual screen image */
struct VIDEO *vp2;	/* physical screen image */

{
#if RAINBOW
/*	UPDATELINE specific code for the DEC rainbow 100 micro	*/

    register char *cp1;
    register char *cp2;
    register int nch;

    /* since we don't know how to make the rainbow do this, turn it off */
    flags &= (~VFREV & ~VFREQ);

    cp1 = &vp1->v_text[0];                    /* Use fast video. */
    cp2 = &vp2->v_text[0];
    putline(row+1, 1, cp1);
    nch = term.t_ncol;

    do
        {
        *cp2 = *cp1;
        ++cp2;
        ++cp1;
        }
    while (--nch);
    *flags &= ~VFCHG;
#else
/*	UPDATELINE code for all other versions		*/

	register char *cp1;
	register char *cp2;
	register char *cp3;
	register char *cp4;
	register char *cp5;
	register int nbflag;	/* non-blanks to the right flag? */
	int rev;		/* reverse video flag */
	int req;		/* reverse video request flag */


	/* set up pointers to virtual and physical lines */
	cp1 = &vp1->v_text[0];
	cp2 = &vp2->v_text[0];

#if	COLOR
	TTforg(vp1->v_rfcolor);
	TTbacg(vp1->v_rbcolor);
#endif

#if	REVSTA | COLOR
	/* if we need to change the reverse video status of the
	   current line, we need to re-write the entire line     */
	rev = (vp1->v_flag & VFREV) == VFREV;
	req = (vp1->v_flag & VFREQ) == VFREQ;
	if ((rev != req)
#if	COLOR
	    || (vp1->v_fcolor != vp1->v_rfcolor) || (vp1->v_bcolor != vp1->v_rbcolor)
#endif
			) {
		movecursor(row, 0);	/* Go to start of line. */
		/* set rev video if needed */
		if (rev != req)
			(*term.t_rev)(req);

		/* scan through the line and dump it to the screen and
		   the virtual screen array				*/
		cp3 = &vp1->v_text[term.t_ncol];
		while (cp1 < cp3) {
			TTputc(*cp1);
			++ttcol;
			*cp2++ = *cp1++;
		}
		/* turn rev video off */
		if (rev != req)
			(*term.t_rev)(FALSE);

		/* update the needed flags */
		vp1->v_flag &= ~VFCHG;
		if (req)
			vp1->v_flag |= VFREV;
		else
			vp1->v_flag &= ~VFREV;
#if	COLOR
		vp1->v_fcolor = vp1->v_rfcolor;
		vp1->v_bcolor = vp1->v_rbcolor;
#endif
		return(TRUE);
	}
#endif

	/* advance past any common chars at the left */
	while (cp1 != &vp1->v_text[term.t_ncol] && cp1[0] == cp2[0]) {
		++cp1;
		++cp2;
	}

/* This can still happen, even though we only call this routine on changed
 * lines. A hard update is always done when a line splits, a massive
 * change is done, or a buffer is displayed twice. This optimizes out most
 * of the excess updating. A lot of computes are used, but these tend to
 * be hard operations that do a lot of update, so I don't really care.
 */
	/* if both lines are the same, no update needs to be done */
	if (cp1 == &vp1->v_text[term.t_ncol]) {
 		vp1->v_flag &= ~VFCHG;		/* flag this line is changed */
		return(TRUE);
	}

	/* find out if there is a match on the right */
	nbflag = FALSE;
	cp3 = &vp1->v_text[term.t_ncol];
	cp4 = &vp2->v_text[term.t_ncol];

	while (cp3[-1] == cp4[-1]) {
		--cp3;
		--cp4;
		if (cp3[0] != ' ')		/* Note if any nonblank */
			nbflag = TRUE;		/* in right match. */
	}

	cp5 = cp3;

	/* Erase to EOL ? */
	if (nbflag == FALSE && eolexist == TRUE && (req != TRUE)) {
		while (cp5!=cp1 && cp5[-1]==' ')
			--cp5;

		if (cp3-cp5 <= 3)		/* Use only if erase is */
			cp5 = cp3;		/* fewer characters. */
	}

	movecursor(row, cp1 - &vp1->v_text[0]);	/* Go to start of line. */
#if	REVSTA
	TTrev(rev);
#endif

	while (cp1 != cp5) {		/* Ordinary. */
		TTputc(*cp1);
		++ttcol;
		*cp2++ = *cp1++;
	}

	if (cp5 != cp3) {		/* Erase. */
		TTeeol();
		while (cp1 != cp3)
			*cp2++ = *cp1++;
	}
#if	REVSTA
	TTrev(FALSE);
#endif
	vp1->v_flag &= ~VFCHG;		/* flag this line as updated */
	return(TRUE);
#endif
}
#endif

/*
 * Redisplay the mode line for the window pointed to by the "wp". This is the
 * only routine that has any idea of how the modeline is formatted. You can
 * change the modeline format by hacking at this routine. Called by "update"
 * any time there is a dirty window.
 */
modeline(wp)
    WINDOW *wp;
{
    register char *cp;
    register int c;
    register int n;		/* cursor position count */
    register BUFFER *bp;
    register int i;		/* loop index */
    register int lchar;		/* character to draw line in buffer with */
    register int firstm;	/* is this the first mode? */
    char tline[NLINE];		/* buffer for part of mode line */

    n = wp->w_toprow+wp->w_ntrows;      	/* Location. */
    vscreen[n]->v_flag |= VFCHG | VFREQ | VFCOL;/* Redraw next time. */
#if	COLOR
    vscreen[n]->v_rfcolor = 0;			/* black on */
    vscreen[n]->v_rbcolor = 7;			/* white.....*/
#endif
    vtmove(n, 0);                       	/* Seek to right line. */
    if (wp == curwp)				/* mark the current buffer */
#if	PKCODE
	lchar = '-';
#else
	lchar = '=';
#endif
    else
#if	REVSTA
	if (revexist)
		lchar = ' ';
	else
#endif
		lchar = '-';

    bp = wp->w_bufp;
#if	PKCODE == 0
    if ((bp->b_flag&BFTRUNC) != 0)
	vtputc('#');
    else
#endif
	vtputc(lchar);

    if ((bp->b_flag&BFCHG) != 0)                /* "*" if changed. */
        vtputc('*');
    else
        vtputc(lchar);

    n  = 2;

    strcpy(tline, " ");
    strcat(tline, PROGNAME);
    strcat(tline, " ");
    strcat(tline, VERSION);
    strcat(tline, ": ");
    cp = &tline[0];
    while ((c = *cp++) != 0)
    {
        vtputc(c);
        ++n;
    }

    cp = &bp->b_bname[0];
    while ((c = *cp++) != 0)
    {
        vtputc(c);
        ++n;
    }

    strcpy(tline, " (");

    /* display the modes */

	firstm = TRUE;
	if ((bp->b_flag&BFTRUNC) != 0)
	{
		firstm = FALSE;
		strcat(tline, "Truncated");
	}
	for (i = 0; i < NUMMODES; i++)	/* add in the mode flags */
		if (wp->w_bufp->b_mode & (1 << i)) {
			if (firstm != TRUE)
				strcat(tline, " ");
			firstm = FALSE;
			strcat(tline, mode2name[i]);
		}
	strcat(tline,") ");

    cp = &tline[0];
    while ((c = *cp++) != 0)
    {
        vtputc(c);
        ++n;
    }

#if 0
    vtputc(lchar);
    vtputc((wp->w_flag&WFCOLR) != 0  ? 'C' : lchar);
    vtputc((wp->w_flag&WFMODE) != 0  ? 'M' : lchar);
    vtputc((wp->w_flag&WFHARD) != 0  ? 'H' : lchar);
    vtputc((wp->w_flag&WFEDIT) != 0  ? 'E' : lchar);
    vtputc((wp->w_flag&WFMOVE) != 0  ? 'V' : lchar);
    vtputc((wp->w_flag&WFFORCE) != 0 ? 'F' : lchar);
    vtputc(lchar);
    n += 8;
#endif

#if	PKCODE
    if (bp->b_fname[0] != 0 &&
    	strcmp(bp->b_bname, bp->b_fname) != 0)
#else
    if (bp->b_fname[0] != 0)            /* File name. */
#endif
        {
#if	PKCODE == 0
        cp = "File: ";

        while ((c = *cp++) != 0)
            {
            vtputc(c);
            ++n;
            }
#endif

        cp = &bp->b_fname[0];

        while ((c = *cp++) != 0)
            {
            vtputc(c);
            ++n;
            }

        vtputc(' ');
        ++n;
        }

    while (n < term.t_ncol)             /* Pad to full width. */
        {
        vtputc(lchar);
        ++n;
        }

	{ /* determine if top line, bottom line, or both are visible */
		LINE *lp = wp->w_linep;
		int rows = wp->w_ntrows;
		char *msg = NULL;

		vtcol = n - 7;  /* strlen(" top ") plus a couple */
		while (rows--) {
			lp = lforw(lp);
			if (lp == wp->w_bufp->b_linep) {
				msg = " Bot ";
				break;
			}
		}
		if (lback(wp->w_linep) == wp->w_bufp->b_linep) {
			if (msg) {
				if (wp->w_linep == wp->w_bufp->b_linep)
					msg = " Emp ";
				else
					msg = " All ";
			} else {
				msg = " Top ";
			}
		}
		if (!msg)
		{
			LINE *lp;
			int numlines, predlines, ratio;

		        lp = lforw(bp->b_linep);
		        numlines = 0;
        		while (lp != bp->b_linep) {
				if (lp == wp->w_linep) {
					predlines = numlines;
				}
				++numlines;
				lp = lforw(lp);
        		}
			if (wp->w_dotp == bp->b_linep) {
				msg = " Bot ";
			} else {
				ratio = 0;
				if (numlines != 0)
					ratio = (100L*predlines) / numlines;
				if (ratio > 99)
					ratio = 99;
				sprintf(tline, " %2d%% ", ratio);
				msg = tline;
			}
		}

		cp = msg;
	        while ((c = *cp++) != 0)
        	{
       			vtputc(c);
			++n;
        	}
	}
}

upmode()	/* update all the mode lines */

{
	register WINDOW *wp;

	wp = wheadp;
	while (wp != NULL) {
		wp->w_flag |= WFMODE;
		wp = wp->w_wndp;
	}
}

/*
 * Send a command to the terminal to move the hardware cursor to row "row"
 * and column "col". The row and column arguments are origin 0. Optimize out
 * random calls. Update "ttrow" and "ttcol".
 */
movecursor(row, col)
    {
    if (row!=ttrow || col!=ttcol)
        {
        ttrow = row;
        ttcol = col;
        TTmove(row, col);
        }
    }

/*
 * Erase the message line. This is a special routine because the message line
 * is not considered to be part of the virtual screen. It always works
 * immediately; the terminal buffer is flushed via a call to the flusher.
 */
mlerase()
    {
    int i;

    movecursor(term.t_nrow, 0);
    if (discmd == FALSE)
    	return;

#if	COLOR
     TTforg(7);
     TTbacg(0);
#endif
    if (eolexist == TRUE)
	    TTeeol();
    else {
        for (i = 0; i < term.t_ncol - 1; i++)
            TTputc(' ');
        movecursor(term.t_nrow, 1);	/* force the move! */
        movecursor(term.t_nrow, 0);
    }
    TTflush();
    mpresf = FALSE;
    }

/*
 * Write a message into the message line. Keep track of the physical cursor
 * position. A small class of printf like format items is handled. Assumes the
 * stack grows down; this assumption is made by the "++" in the argument scan
 * loop. Set the "message line" flag TRUE.
 */

mlwrite(fmt, arg)

char *fmt;	/* format string for output */
char *arg;	/* pointer to first argument to print */

{
	register int c;		/* current char in format string */
	register char *ap;	/* ptr to current data field */

	/* if we are not currently echoing on the command line, abort this */
	if (discmd == FALSE) {
		movecursor(term.t_nrow, 0);
		return;
	}

#if	COLOR
	/* set up the proper colors for the command line */
	TTforg(7);
	TTbacg(0);
#endif

	/* if we can not erase to end-of-line, do it manually */
	if (eolexist == FALSE) {
		mlerase();
		TTflush();
	}

	movecursor(term.t_nrow, 0);
	ap = (char *) &arg;
	while ((c = *fmt++) != 0) {
		if (c != '%') {
			TTputc(c);
			++ttcol;
		} else {
			c = *fmt++;
			switch (c) {
#if	PKCODE
				case '*':
					ap = *(char **)ap;
					break;
#endif
				case 'd':
					mlputi(*(int *)ap, 10);
					ap += sizeof(int);
					break;

				case 'o':
					mlputi(*(int *)ap,  8);
					ap += sizeof(int);
					break;

				case 'x':
					mlputi(*(int *)ap, 16);
					ap += sizeof(int);
					break;

				case 'D':
					mlputli(*(long *)ap, 10);
					ap += sizeof(long);
					break;

				case 's':
					mlputs(*(char **)ap);
					ap += sizeof(char *);
					break;

				case 'f':
					mlputf(*(int *)ap);
					ap += sizeof(int);
					break;

				default:
					TTputc(c);
					++ttcol;
			}
		}
	}

	/* if we can, erase to the end of screen */
	if (eolexist == TRUE)
		TTeeol();
	TTflush();
	mpresf = TRUE;
}

/*	Force a string out to the message line regardless of the
	current $discmd setting. This is needed when $debug is TRUE
	and for the write-message and clear-message-line commands
*/

mlforce(s)

char *s;	/* string to force out */

{
	register int oldcmd;	/* original command display flag */

	oldcmd = discmd;	/* save the discmd value */
	discmd = TRUE;		/* and turn display on */
	mlwrite(s);		/* write the string out */
	discmd = oldcmd;	/* and restore the original setting */
}

/*
 * Write out a string. Update the physical cursor position. This assumes that
 * the characters in the string all have width "1"; if this is not the case
 * things will get screwed up a little.
 */
mlputs(s)
    char *s;
    {
    register int c;

    while ((c = *s++) != 0)
        {
        TTputc(c);
        ++ttcol;
        }
    }

/*
 * Write out an integer, in the specified radix. Update the physical cursor
 * position.
 */
mlputi(i, r)
    {
    register int q;
    static char hexdigits[] = "0123456789ABCDEF";

    if (i < 0)
        {
        i = -i;
        TTputc('-');
        }

    q = i/r;

    if (q != 0)
        mlputi(q, r);

    TTputc(hexdigits[i%r]);
    ++ttcol;
    }

/*
 * do the same except as a long integer.
 */
mlputli(l, r)
    long l;
    {
    register long q;

    if (l < 0)
        {
        l = -l;
        TTputc('-');
        }

    q = l/r;

    if (q != 0)
        mlputli(q, r);

    TTputc((int)(l%r)+'0');
    ++ttcol;
    }

/*
 *	write out a scaled integer with two decimal places
 */

mlputf(s)

int s;	/* scaled integer to output */

{
	int i;	/* integer portion of number */
	int f;	/* fractional portion of number */

	/* break it up */
	i = s / 100;
	f = s % 100;

	/* send out the integer portion */
	mlputi(i, 10);
	TTputc('.');
	TTputc((f / 10) + '0');
	TTputc((f % 10) + '0');
	ttcol += 3;
}	

#if RAINBOW

putline(row, col, buf)
    int row, col;
    char buf[];
    {
    int n;

    n = strlen(buf);
    if (col + n - 1 > term.t_ncol)
        n = term.t_ncol - col + 1;
    Put_Data(row, col, n, buf);
    }
#endif

/* Get terminal size from system.
   Store number of lines into *heightp and width into *widthp.
   If zero or a negative number is stored, the value is not valid.  */
        
getscreensize (widthp, heightp)
int *widthp, *heightp;
{               
#ifdef TIOCGWINSZ
        struct winsize size;
        *widthp = 0;
        *heightp = 0;
        if (ioctl (0, TIOCGWINSZ, &size) < 0)
                return;
        *widthp = size.ws_col;
        *heightp = size.ws_row;
#else
        *widthp = 0;
        *heightp = 0;
#endif          
}       
 
#ifdef SIGWINCH
void sizesignal(signr)
int signr;
{
        int w, h;
        extern int errno;
        int old_errno = errno;
 
        getscreensize (&w, &h);
        
        if (h && w && (h-1 != term.t_nrow || w != term.t_ncol))
                newscreensize(h, w);

        signal (SIGWINCH, sizesignal);
        errno = old_errno;
}
        
newscreensize (h, w) 
int h, w;
{       
        /* do the change later */
        if (displaying) {
                chg_width = w;
                chg_height = h;
                return;
        }
        chg_width = chg_height = 0;
        if (h - 1 < term.t_mrow)
                newsize(TRUE,h);
        if (w < term.t_mcol)
                newwidth(TRUE,w);
                
        update(TRUE);
        return TRUE;
}
 
#endif