-> 1.03

[nvi.git] / vi / vs_refresh.c

/*-
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#ifndef lint
static char sccsid[] = "$Id: vs_refresh.c,v 8.43 1993/12/23 10:22:03 bostic Exp $ (Berkeley) $Date: 1993/12/23 10:22:03 $";
#endif /* not lint */

#include <sys/types.h>

#include <ctype.h>
#include <curses.h>
#include <stdlib.h>
#include <string.h>

#include "vi.h"
#include "svi_screen.h"
#include "sex/sex_screen.h"

static int      svi_modeline __P((SCR *, EXF *));
static int      svi_msgflush __P((SCR *));

int
svi_refresh(sp, ep)
        SCR *sp;
        EXF *ep;
{
        SCR *tsp;
        u_int paintbits;

        /*
         * 1: Resize the screen.
         *
         * Notice that a resize is requested, and set up everything so that
         * the file gets reinitialized.  Done here, instead of in the vi loop
         * because there may be other initialization that other screens need
         * to do.  The actual changing of the row/column values was done by
         * calling the ex options code which put them into the environment,
         * which is used by curses.  Stupid, but ugly.
         */
        if (F_ISSET(sp, S_RESIZE)) {
                /* Reinitialize curses. */
                if (svi_curses_end(sp) || svi_curses_init(sp))
                        return (1);

                /* Lose any svi_screens() cached information. */
                SVP(sp)->ss_lno = OOBLNO;

                /*
                 * Fill the map, incidentally losing any svi_line()
                 * cached information.
                 */
                if (sp->s_fill(sp, ep, sp->lno, P_FILL))
                        return (1);
                F_CLR(sp, S_RESIZE | S_REFORMAT);
                F_SET(sp, S_REDRAW);
        }

        /*
         * 2: S_REFRESH
         *
         * If S_REFRESH is set in the current screen, repaint everything
         * that we can find.
         */
        if (F_ISSET(sp, S_REFRESH))
                for (tsp = sp->gp->dq.cqh_first;
                    tsp != (void *)&sp->gp->dq; tsp = tsp->q.cqe_next)
                        if (tsp != sp)
                                F_SET(tsp, S_REDRAW);
        /*
         * 3: Related or dirtied screens, or screens with messages.
         *
         * If related screens share a view into a file, they may have been
         * modified as well.  Refresh any screens with paint or dirty bits
         * set, or where messages are waiting.  Finally, if we refresh any
         * screens other than the current one, the cursor will be trashed.
         */
        paintbits = S_REDRAW | S_REFORMAT | S_REFRESH;
        if (O_ISSET(sp, O_NUMBER))
                paintbits |= S_RENUMBER;
        for (tsp = sp->gp->dq.cqh_first;
            tsp != (void *)&sp->gp->dq; tsp = tsp->q.cqe_next)
                if (tsp != sp &&
                    (F_ISSET(tsp, paintbits) ||
                    F_ISSET(SVP(tsp), SVI_SCREENDIRTY) ||
                    tsp->msgq.lh_first != NULL &&
                    !F_ISSET(tsp->msgq.lh_first, M_EMPTY))) {
                        (void)svi_paint(tsp, tsp->ep);
                        F_CLR(SVP(tsp), SVI_SCREENDIRTY);
                        F_SET(SVP(sp), SVI_CUR_INVALID);
                }

        /*
         * 4: Refresh the current screen.
         *
         * Always refresh the current screen, it may be a cursor movement.
         * Also, always do it last -- that way, S_REFRESH can be set in
         * the current screen only, and the screen won't flash.
         */
        F_CLR(sp, SVI_SCREENDIRTY);
        return (svi_paint(sp, ep));
}

/*
 * svi_paint --
 *      This is the guts of the vi curses screen code.  The idea is that
 *      the SCR structure passed in contains the new coordinates of the
 *      screen.  What makes this hard is that we don't know how big
 *      characters are, doing input can put the cursor in illegal places,
 *      and we're frantically trying to avoid repainting unless it's
 *      absolutely necessary.  If you change this code, you'd better know
 *      what you're doing.  It's subtle and quick to anger.
 */
int
svi_paint(sp, ep)
        SCR *sp;
        EXF *ep;
{
        CHNAME const *cname;
        SMAP *smp, tmp;
        SVI_PRIVATE *svp;
        recno_t lastline, lcnt;
        size_t cwtotal, cnt, len, x, y;
        int ch, didpaint;
        char *p;

#define  LNO    sp->lno
#define OLNO    svp->olno
#define  CNO    sp->cno
#define OCNO    svp->ocno
#define SCNO    svp->sc_col

        didpaint = 0;
        svp = SVP(sp);

        /*
         * 1: Reformat the lines.
         *
         * If the lines themselves have changed (:set list, for example),
         * fill in the map from scratch.  Adjust the screen that's being
         * displayed if the leftright flag is set.
         */
        if (F_ISSET(sp, S_REFORMAT)) {
                /* Toss svi_screens() cached information. */
                SVP(sp)->ss_lno = OOBLNO;

                /* Toss svi_line() cached information. */
                if (svi_sm_fill(sp, ep, HMAP->lno, P_TOP))
                        return (1);
                if (O_ISSET(sp, O_LEFTRIGHT) &&
                    (cnt = svi_screens(sp, ep, LNO, &CNO)) != 1)
                        for (smp = HMAP; smp <= TMAP; ++smp)
                                smp->off = cnt;
                F_CLR(sp, S_REFORMAT);
                F_SET(sp, S_REDRAW);
        }

        /*
         * 2: Line movement.
         *
         * Line changes can cause the top line to change as well.  As
         * before, if the movement is large, the screen is repainted.
         *
         * 2a: Tiny screens.
         *
         * Tiny screens cannot be permitted into the "scrolling" parts of
         * the smap code for two reasons.  If the screen size is 1 line,
         * HMAP == TMAP and the code will quickly drop core.  If the screen
         * size is 2, none of the divisions by 2 will work, and scrolling
         * won't work.  In fact, because no line change will be less than
         * HALFTEXT(sp), we always ending up "filling" the map, with a
         * P_MIDDLE flag, which isn't what the user wanted.  Tiny screens
         * can go into the "fill" portions of the smap code, however.
         */
        if (sp->t_rows <= 2) {
                if (LNO < HMAP->lno) {
                        if (svi_sm_fill(sp, ep, LNO, P_TOP))
                                return (1);
                } else if (LNO > TMAP->lno)
                        if (svi_sm_fill(sp, ep, LNO, P_BOTTOM))
                                return (1);
                if (sp->t_rows == 1) {
                        HMAP->off = svi_screens(sp, ep, LNO, &CNO);
                        goto paint;
                }
                F_SET(sp, S_REDRAW);
                goto adjust;
        }

        /*
         * 2b: Small screens.
         *
         * Users can use the window, w300, w1200 and w9600 options to make
         * the screen artificially small.  The behavior of these options
         * in the historic vi wasn't all that consistent, and, in fact, it
         * was never documented how various screen movements affected the
         * screen size.  Generally, one of three things would happen:
         *      1: The screen would expand in size, showing the line
         *      2: The screen would scroll, showing the line
         *      3: The screen would compress to its smallest size and
         *              repaint.
         * In general, scrolling didn't cause compression (200^D was handled
         * the same as ^D), movement to a specific line would (:N where N
         * was 1 line below the screen caused a screen compress), and cursor
         * movement would scroll if it was 11 lines or less, and compress if
         * it was more than 11 lines.  (And, no, I have no idea where the 11
         * comes from.)
         *
         * What we do is try and figure out if the line is less than half of
         * a full screen away.  If it is, we expand the screen if there's
         * room, and then scroll as necessary.  The alternative is to compress
         * and repaint.
         *
         * !!!
         * This code is a special case from beginning to end.  Unfortunately,
         * home modems are still slow enough that it's worth having.
         *
         * XXX
         * If the line a really long one, i.e. part of the line is on the
         * screen but the column offset is not, we'll end up in the adjust
         * code, when we should probably have compressed the screen.
         */
        if (ISSMALLSCREEN(sp))
                if (LNO < HMAP->lno) {
                        lcnt = svi_sm_nlines(sp, ep, HMAP, LNO, sp->t_maxrows);
                        if (lcnt <= HALFSCREEN(sp))
                                for (; lcnt && sp->t_rows != sp->t_maxrows;
                                     --lcnt, ++sp->t_rows) {
                                        ++TMAP;
                                        if (svi_sm_1down(sp, ep))
                                                return (1);
                                }
                        else
                                goto small_fill;
                } else if (LNO > TMAP->lno) {
                        lcnt = svi_sm_nlines(sp, ep, TMAP, LNO, sp->t_maxrows);
                        if (lcnt <= HALFSCREEN(sp))
                                for (; lcnt && sp->t_rows != sp->t_maxrows;
                                     --lcnt, ++sp->t_rows) {
                                        if (svi_sm_next(sp, ep, TMAP, TMAP + 1))
                                                return (1);
                                        ++TMAP;
                                        if (svi_line(sp, ep, TMAP, NULL, NULL))
                                                return (1);
                                }
                        else {
small_fill:                     MOVE(sp, INFOLINE(sp), 0);
                                clrtoeol();
                                for (; sp->t_rows > sp->t_minrows;
                                    --sp->t_rows, --TMAP) {
                                        MOVE(sp, TMAP - HMAP, 0);
                                        clrtoeol();
                                }
                                if (svi_sm_fill(sp, ep, LNO, P_FILL))
                                        return (1);
                                F_SET(sp, S_REDRAW);
                                goto adjust;
                        }
                }

        /*
         * 3a: Line down.
         */
        if (LNO >= HMAP->lno) {
                if (LNO <= TMAP->lno)
                        goto adjust;

                /*
                 * If less than half a screen away, scroll down until the
                 * line is on the screen.
                 */
                lcnt = svi_sm_nlines(sp, ep, TMAP, LNO, HALFTEXT(sp));
                if (lcnt < HALFTEXT(sp)) {
                        while (lcnt--)
                                if (svi_sm_1up(sp, ep))
                                        return (1);
                        goto adjust;
                }

                /*
                 * If less than a full screen from the bottom of the file, put
                 * the last line of the file on the bottom of the screen.  The
                 * calculation is safe because we know there's at least one
                 * full screen of lines, otherwise couldn't have gotten here.
                 */
                if (file_lline(sp, ep, &lastline))
                        return (1);
                tmp.lno = LNO;
                tmp.off = 1;
                lcnt = svi_sm_nlines(sp, ep, &tmp, lastline, sp->t_rows);
                if (lcnt < sp->t_rows) {
                        if (svi_sm_fill(sp, ep, lastline, P_BOTTOM))
                                return (1);
                        F_SET(sp, S_REDRAW);
                        goto adjust;
                }

                /*
                 * If more than a full screen from the last line of the file,
                 * put the new line in the middle of the screen.
                 */
                goto middle;
        }

        /*
         * 3b: Line up.
         *
         * If less than half a screen away, scroll up until the line is
         * the first line on the screen.
         */
        lcnt = svi_sm_nlines(sp, ep, HMAP, LNO, HALFTEXT(sp));
        if (lcnt < HALFTEXT(sp)) {
                while (lcnt--)
                        if (svi_sm_1down(sp, ep))
                                return (1);
                goto adjust;
        }

        /*
         * If less than half a screen from the top of the file, put the first
         * line of the file at the top of the screen.  Otherwise, put the line
         * in the middle of the screen.
         */
        tmp.lno = 1;
        tmp.off = 1;
        lcnt = svi_sm_nlines(sp, ep, &tmp, LNO, HALFTEXT(sp));
        if (lcnt < HALFTEXT(sp)) {
                if (svi_sm_fill(sp, ep, 1, P_TOP))
                        return (1);
        } else
middle:         if (svi_sm_fill(sp, ep, LNO, P_MIDDLE))
                        return (1);
        F_SET(sp, S_REDRAW);

        /*
         * At this point we know part of the line is on the screen.  Since
         * scrolling is done using logical lines, not physical, all of the
         * line may not be on the screen.  While that's not necessarily bad,
         * if the part the cursor is on isn't there, we're going to lose.
         * This can be tricky; if the line covers the entire screen, lno
         * may be the same as both ends of the map, that's why we test BOTH
         * the top and the bottom of the map.  This isn't a problem for
         * left-right scrolling, the cursor movement code handles the problem.
         *
         * There's a performance issue here if editing *really* long lines.
         * This gets to the right spot by scrolling, and, in a binary, by
         * scrolling hundreds of lines.  If the adjustment looks like it's
         * going to be a serious problem, refill the screen and repaint.
         */
adjust: if (!O_ISSET(sp, O_LEFTRIGHT) &&
            (LNO == HMAP->lno || LNO == TMAP->lno)) {
                cnt = svi_screens(sp, ep, LNO, &CNO);
                if (LNO == HMAP->lno && cnt < HMAP->off)
                        if ((HMAP->off - cnt) > HALFTEXT(sp)) {
                                HMAP->off = cnt;
                                svi_sm_fill(sp, ep, OOBLNO, P_TOP);
                                F_SET(sp, S_REDRAW);
                        } else
                                while (cnt < HMAP->off)
                                        if (svi_sm_1down(sp, ep))
                                                return (1);
                if (LNO == TMAP->lno && cnt > TMAP->off)
                        if ((cnt - TMAP->off) > HALFTEXT(sp)) {
                                TMAP->off = cnt;
                                svi_sm_fill(sp, ep, OOBLNO, P_BOTTOM);
                                F_SET(sp, S_REDRAW);
                        } else
                                while (cnt > TMAP->off)
                                        if (svi_sm_1up(sp, ep))
                                                return (1);
        }

        /* If the screen needs to be repainted, skip cursor optimization. */
        if (F_ISSET(sp, S_REDRAW))
                goto paint;

        /*
         * 4: Cursor movements.
         *
         * Decide cursor position.  If the line has changed, the cursor has
         * moved over a tab, or don't know where the cursor was, reparse the
         * line.  Note, if we think that the cursor "hasn't moved", reparse
         * the line.  This is 'cause if it hasn't moved, we've almost always
         * lost track of it.
         *
         * Otherwise, we've just moved over fixed-width characters, and can
         * calculate the left/right scrolling and cursor movement without
         * reparsing the line.  Note that we don't know which (if any) of
         * the characters between the old and new cursor positions changed.
         *
         * XXX
         * With some work, it should be possible to handle tabs quickly, at
         * least in obvious situations, like moving right and encountering
         * a tab, without reparsing the whole line.
         */

        /* If the line we're working with has changed, reparse. */
        if (F_ISSET(SVP(sp), SVI_CUR_INVALID) || LNO != OLNO) {
                F_CLR(SVP(sp), SVI_CUR_INVALID);
                goto slow;
        }

        /* Otherwise, if nothing's changed, go fast. */
        if (CNO == OCNO)
                goto fast;

        /*
         * Get the current line.  If this fails, we either have an empty
         * file and can just repaint, or there's a real problem.  This
         * isn't a performance issue because there aren't any ways to get
         * here repeatedly.
         */
        if ((p = file_gline(sp, ep, LNO, &len)) == NULL) {
                if (file_lline(sp, ep, &lastline))
                        return (1);
                if (lastline == 0)
                        goto slow;
                GETLINE_ERR(sp, LNO);
                return (1);
        }

#ifdef DEBUG
        /* This is just a test. */
        if (CNO >= len && len != 0) {
                msgq(sp, M_ERR, "Error: %s/%d: cno (%u) >= len (%u)",
                     tail(__FILE__), __LINE__, CNO, len);
                return (1);
        }
#endif
        /*
         * The basic scheme here is to look at the characters in between
         * the old and new positions and decide how big they are on the
         * screen, and therefore, how many screen positions to move.
         */
        cname = sp->gp->cname;
        if (CNO < OCNO) {
                /*
                 * 4a: Cursor moved left.
                 *
                 * Point to the old character.  The old cursor position can
                 * be past EOL if, for example, we just deleted the rest of
                 * the line.  In this case, since we don't know the width of
                 * the characters we traversed, we have to do it slowly.
                 */
                p += OCNO;
                cnt = (OCNO - CNO) + 1;
                if (OCNO >= len)
                        goto slow;

                /*
                 * Quit sanity check -- it's hard to figure out exactly when
                 * we cross a screen boundary as we do in the cursor right
                 * movement.  If cnt is so large that we're going to cross the
                 * boundary no matter what, stop now.
                 */
                if (SCNO + 1 + MAX_CHARACTER_COLUMNS < cnt)
                        goto lscreen;

                /*
                 * Count up the widths of the characters.  If it's a tab
                 * character, go do it the the slow way.
                 */
                for (cwtotal = 0; cnt--; cwtotal += cname[ch].len)
                        if ((ch = *(u_char *)p--) == '\t')
                                goto slow;

                /*
                 * Decrement the screen cursor by the total width of the
                 * characters minus 1.
                 */
                cwtotal -= 1;

                /*
                 * If we're moving left, and there's a wide character in the
                 * current position, go to the end of the character.
                 */
                if (cname[ch].len > 1)
                        cwtotal -= cname[ch].len - 1;

                /*
                 * If the new column moved us out of the current screen,
                 * calculate a new screen.
                 */
                if (SCNO < cwtotal) {
lscreen:                if (O_ISSET(sp, O_LEFTRIGHT)) {
                                for (smp = HMAP; smp <= TMAP; ++smp)
                                        --smp->off;
                                goto paint;
                        }
                        goto slow;
                }
                SCNO -= cwtotal;
        } else {
                /*
                 * 4b: Cursor moved right.
                 *
                 * Point to the first character to the right.
                 */
                p += OCNO + 1;
                cnt = CNO - OCNO;

                /*
                 * Count up the widths of the characters.  If it's a tab
                 * character, go do it the the slow way.  If we cross a
                 * screen boundary, we can quit.
                 */
                for (cwtotal = SCNO; cnt--;) {
                        if ((ch = *(u_char *)p++) == '\t')
                                goto slow;
                        if ((cwtotal += cname[ch].len) >= SCREEN_COLS(sp))
                                break;
                }

                /*
                 * Increment the screen cursor by the total width of the
                 * characters.
                 */
                SCNO = cwtotal;

                /*
                 * If the new column moved us out of the current screen,
                 * calculate a new screen.
                 */
                if (SCNO >= SCREEN_COLS(sp)) {
                        if (O_ISSET(sp, O_LEFTRIGHT)) {
                                SCNO -= SCREEN_COLS(sp);
                                for (smp = HMAP; smp <= TMAP; ++smp)
                                        ++smp->off;
                                goto paint;
                        }
                        goto slow;
                }
        }

        /*
         * 4c: Fast cursor update.
         *
         * Retrieve the current cursor position, and correct it
         * for split screens.
         */
fast:   getyx(stdscr, y, x);
        y -= sp->woff;
        goto number;

        /*
         * 4d: Slow cursor update.
         *
         * Walk through the map and find the current line.  If doing left-right
         * scrolling and the cursor movement has changed the screen displayed,
         * scroll the screen left or right, unless we're updating the info line
         * in which case we just scroll that one line.  Then update the screen
         * lines for this file line until we have a new screen cursor position.
         */
slow:   for (smp = HMAP; smp->lno != LNO; ++smp);
        if (O_ISSET(sp, O_LEFTRIGHT)) {
                cnt = svi_screens(sp, ep, LNO, &CNO) % SCREEN_COLS(sp);
                if (cnt != HMAP->off) {
                        if (ISINFOLINE(sp, smp))
                                smp->off = cnt;
                        else
                                for (smp = HMAP; smp <= TMAP; ++smp)
                                        smp->off = cnt;
                        goto paint;
                }
        }
        for (y = -1; smp <= TMAP && smp->lno == LNO; ++smp) {
                if (svi_line(sp, ep, smp, &y, &SCNO))
                        return (1);
                if (y != -1)
                        break;
        }
        goto number;

        /*
         * 5: Repaint the entire screen.
         *
         * Lost big, do what you have to do.  We flush the cache as S_REDRAW
         * gets set when the screen isn't worth fixing, and it's simpler to
         * repaint.  So, don't trust anything that we think we know about it.
         */
paint:  for (smp = HMAP; smp <= TMAP; ++smp)
                SMAP_FLUSH(smp);
        for (smp = HMAP; smp <= TMAP; ++smp)
                if (svi_line(sp, ep, smp, &y, &SCNO))
                        return (1);
        /*
         * If it's a small screen and we're redrawing, clear the unused lines,
         * ex may have overwritten them.
         */
        if (F_ISSET(sp, S_REDRAW)) {
                if (ISSMALLSCREEN(sp))
                        for (cnt = sp->t_rows; cnt <= sp->t_maxrows; ++cnt) {
                                MOVE(sp, cnt, 0);
                                clrtoeol();
                        }
                F_CLR(sp, S_REDRAW);
        }

        didpaint = 1;

        /*
         * 6: Repaint the line numbers.
         *
         * If O_NUMBER is set and the S_RENUMBER bit is set, and we didn't
         * repaint the screen, repaint all of the line numbers, they've
         * changed.
         */
number: if (O_ISSET(sp, O_NUMBER) && F_ISSET(sp, S_RENUMBER) && !didpaint) {
                if (svi_number(sp, ep))
                        return (1);
                F_CLR(sp, S_RENUMBER);
        }

        /*
         * 7: Refresh the screen.
         *
         * If the screen was corrupted, refresh it.
         */
        if (F_ISSET(sp, S_REFRESH)) {
                wrefresh(curscr);
                F_CLR(sp, S_REFRESH);
        }

        if (F_ISSET(sp, S_BELLSCHED))
                svi_bell(sp);
        /*
         * If the bottom line isn't in use by the colon command:
         *
         *      Display any messages.  Don't test S_UPDATE_MODE.  The
         *      message printing routine set it to avoid anyone else
         *      destroying the message we're about to display.
         *
         *      If the bottom line isn't in use by anyone, put out the
         *      standard status line.
         */
        if (!F_ISSET(SVP(sp), SVI_INFOLINE))
                if (sp->msgq.lh_first != NULL &&
                    !F_ISSET(sp->msgq.lh_first, M_EMPTY))
                        svi_msgflush(sp);
                else if (!F_ISSET(sp, S_UPDATE_MODE))
                        svi_modeline(sp, ep);

        /* Update saved information. */
        OCNO = CNO;
        OLNO = LNO;

        /* Place the cursor. */
        MOVE(sp, y, SCNO);

        /* Flush it all out. */
        refresh();

        return (0);
}

/*
 * svi_msgflush --
 *      Flush any accumulated messages.
 */
static int
svi_msgflush(sp)
        SCR *sp;
{
        CH ikey;
        CHAR_T ch;
        CHNAME const *cname;
        MSG *mp;
        size_t chlen, len;
        char *p;

#define MCONTMSG        " [More ...]"

        /* Display the messages. */
        cname = sp->gp->cname;
        for (mp = sp->msgq.lh_first, p = NULL;
            mp != NULL && !F_ISSET(mp, M_EMPTY); mp = mp->q.le_next) {
                p = mp->mbuf;

lcont:          /* Move to the message line and clear it. */
                MOVE(sp, INFOLINE(sp), 0);
                clrtoeol();

                /*
                 * Turn on standout mode if requested, or, if we've split
                 * the screen and need a divider.
                 */
                if (F_ISSET(mp, M_INV_VIDEO) ||
                    sp->q.cqe_next != (void *)&sp->gp->dq)
                        standout();

                /*
                 * Print up to the "more" message.  Avoid the last character
                 * in the last line, some hardware doesn't like it.
                 */
                if (svi_ncols(sp, p, mp->len, NULL) < sp->cols - 1)
                        len = sp->cols - 1;
                else
                        len = (sp->cols - sizeof(MCONTMSG)) - 1;
                for (;; ++p) {
                        if (!mp->len)
                                break;
                        ch = *(u_char *)p;
                        chlen = cname[ch].len;
                        if (chlen >= len)
                                break;
                        len -= chlen;
                        --mp->len;
                        ADDNSTR(cname[ch].name, chlen);
                }

                /*
                 * If more, print continue message.  If user key fails,
                 * keep showing the messages anyway.
                 */
                if (mp->len || (mp->q.le_next != NULL &&
                    !F_ISSET(mp->q.le_next, M_EMPTY))) {
                        ADDNSTR(MCONTMSG, sizeof(MCONTMSG) - 1);
                        refresh();
                        for (;;) {
                                if (term_user_key(sp, &ikey) != INP_OK)
                                        break;
                                if (ikey.value == K_CR ||
                                    ikey.value == K_NL || ikey.ch == ' ')
                                        break;
                                svi_bell(sp);
                        }
                }

                /* Turn off standout mode. */
                if (F_ISSET(mp, M_INV_VIDEO) ||
                    sp->q.cqe_next != (void *)&sp->gp->dq)
                        standend();

                if (mp->len)
                        goto lcont;

                refresh();
                F_SET(mp, M_EMPTY);
        }
        return (0);
}

#define RULERSIZE       15
#define MODESIZE        (RULERSIZE + 15)

/*
 * svi_modeline --
 *      Update the mode line.
 */
static int
svi_modeline(sp, ep)
        SCR *sp;
        EXF *ep;
{
        char *s, buf[RULERSIZE];

        MOVE(sp, INFOLINE(sp), 0);
        clrtoeol();

        /* Display a dividing line if not the bottom screen. */
        if (sp->q.cqe_next != (void *)&sp->gp->dq)
                svi_divider(sp);

        /* Display the ruler. */
        if (O_ISSET(sp, O_RULER) && sp->cols > RULERSIZE + 2) {
                MOVE(sp, INFOLINE(sp), sp->cols / 2 - RULERSIZE / 2);
                clrtoeol();
                (void)snprintf(buf,
                    sizeof(buf), "%lu,%lu", sp->lno, sp->cno + 1);
                ADDSTR(buf);
        }

        /* Show the modified bit. */
        if (O_ISSET(sp, O_SHOWDIRTY) &&
            F_ISSET(ep, F_MODIFIED) && sp->cols > MODESIZE) {
                MOVE(sp, INFOLINE(sp), sp->cols - 9);
                ADDSTR("*");
        }

        /*
         * Show the mode.  Leave the last character blank, in case it's a
         * really dumb terminal with hardware scroll.  Second, don't try
         * to *paint* the last character, SunOS 4.1.1 and Ultrix 4.2 curses
         * won't let you paint the last character in the screen.
         */
        if (O_ISSET(sp, O_SHOWMODE) && sp->cols > MODESIZE) {
                MOVE(sp, INFOLINE(sp), sp->cols - 8);
                s = F_ISSET(sp, S_INPUT) ? "  Input" : "Command";
                ADDSTR(s);
        }

        return (0);
}

/*
 * svi_divider --
 *      Draw a dividing line between the screens.
 */
int
svi_divider(sp)
        SCR *sp;
{
        size_t len;

#define DIVIDESTR       "+=+=+=+=+=+=+=+"
        len = sizeof(DIVIDESTR) - 1 > sp->cols ?
            sp->cols : sizeof(DIVIDESTR) - 1;
        ADDNSTR(DIVIDESTR, len);
        return (0);
}