vi/port/ex_vadj.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*  Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */


/* Copyright (c) 1981 Regents of the University of California */

#include "ex.h"
#include "ex_tune.h"
#include "ex_tty.h"
#include "ex_vis.h"

/*
 * Routines to deal with management of logical versus physical
 * display, opening and redisplaying lines on the screen, and
 * use of intelligent terminal operations.  Routines to deal with
 * screen cleanup after a change.
 */

/*
 * Display a new line at physical line p, returning
 * the depth of the newly displayed line.  We may decide
 * to expand the window on an intelligent terminal if it is
 * less than a full screen by deleting a line above the top of the
 * window before doing an insert line to keep all the good text
 * on the screen in which case the line may actually end up
 * somewhere other than line p.
 */
void
vopen(line *tp, int p)
{
    int cnt;
    struct vlinfo *vp, *vpc;

#ifdef ADEBUG
    if (trace != NULL)
        tfixnl(), fprintf(trace, "vopen(%d, %d)\n", lineno(tp), p);
#endif
    if (state != VISUAL) {
        if (vcnt)
            if (hold & HOLDROL)
                vup1();
            else
                vclean();

        /*
         * Forget all that we once knew.
         */
        vcnt = vcline = 0;
        p = WBOT; LASTLINE = WBOT + 1;
        state = bastate;
        WTOP = basWTOP;
        WLINES = basWLINES;
    }
    vpc = &vlinfo[vcline];
    for (vp = &vlinfo[vcnt]; vp >= vpc; vp--)
        vlcopy(vp[1], vp[0]);
    vcnt++;
    if (Pline == numbline)
        /*
         * Dirtying all the lines is rather inefficient
         * internally, but number mode is used rarely
         * and so it's not worth optimizing.
         */
        vdirty(vcline+1, WECHO);
    getaline(*tp);

    /*
     * If we are opening at the top of the window, can try a window
     * expansion at the top.
     */
    if (state == VISUAL && vcline == 0 && vcnt > 1 && p > ZERO) {
        cnt = p + vdepth() - LINE(1);
        if (cnt > 0) {
            p -= cnt;
            if (p < ZERO)
                p = ZERO;
            WTOP = p;
            WLINES = WBOT - WTOP + 1;
        }
    }
    vpc->vliny = p, vpc->vdepth = 0, vpc->vflags = 0;
    cnt = vreopen(p, lineno(tp), vcline);
    if (vcline + 1 == vcnt)
        LINE(vcnt) = LINE(vcline) + cnt;
}

/*
 * Redisplay logical line l at physical line p with line number lineno.
 */
int
vreopen(int p, int lineno, int l)
{
    int d;
    struct vlinfo *vp = &vlinfo[l];

    d = vp->vdepth;
    if (d == 0 || (vp->vflags & VDIRT))
        vp->vdepth = d = vdepth();
    vp->vliny = p, vp->vflags &= ~VDIRT;

    /*
     * Try to win by making the screen larger rather than inserting
     * a line and driving text off the bottom.
     */
    p = vglitchup(l, 0);

    /*
     * BUG: Should consider using clr_eol here to clear to end of line.
     *  As it stands we always strike over the current text.
     *  Since often the current text is the same as what
     *  we are overstriking with, it tends not to show.
     *  On the other hand if it is different and we end up
     *  spacing out a lot of text, we could have won with
     *  a clr_eol.  This is probably worthwhile at low speed
     *  only however, since clearly computation will be
     *  necessary to determine which way to go.
     */
    vigoto(p, 0);
    pline(lineno);

    if (state == VISUAL && l == vcline && vp->vliny < 0) {
        vp->vliny = 0;
        vscrap();
        return (d);
    }

    /*
     * When we are typing part of a line for hardcopy open, don't
     * want to type the '$' marking an end of line if in list mode.
     */
    if (hold & HOLDDOL)
        return (d);
    if (Putchar == listchar)
        putchar('$');

    /*
     * Optimization of cursor motion may prevent screen rollup if the
     * line has blanks/tabs at the end unless we force the cursor to appear
     * on the last line segment.
     */
    if (vp->vliny + d - 1 > WBOT)
        vcsync();

    /*
     * Switch into hardcopy open mode if we are in one line (adm3)
     * open mode and this line is now too long.  If in hardcopy
     * open mode, then call sethard to move onto the next line
     * with appropriate positioning.
     */
    if (state == ONEOPEN) {
        WCOLS = OCOLUMNS;
        if (vdepth() > 1) {
            WCOLS = TUBECOLS;
            sethard();
        } else
            WCOLS = TUBECOLS;
    } else if (state == HARDOPEN)
        sethard();

    /*
     * Unless we filled (completely) the last line we typed on,
     * we have to clear to the end of the line
     * in case stuff is left from before.
     */
    if (vp->vliny + d > destline) {
        if (insert_null_glitch && destcol == WCOLS)
            vigoto(vp->vliny + d - 1, 0);
        vclreol();
    }
    return (d);
}

/*
 * Real work for winning growing of window at top
 * when inserting in the middle of a partially full
 * screen on an intelligent terminal.  We have as argument
 * the logical line number to be inserted after, and the offset
 * from that line where the insert will go.
 * We look at the picture of depths and positions, and if we can
 * delete some (blank) lines from the top of the screen so that
 * later inserts will not push stuff off the bottom.
 */
int
vglitchup(int l, int o)
{
    struct vlinfo *vp = &vlinfo[l];
    int need;
    int p = vp->vliny;
    short oldhold, oldheldech;
    bool glitched = 0;

    if (l < vcnt - 1) {
        need = p + vp->vdepth - (vp+1)->vliny;
        if (need > 0) {
            if (state == VISUAL && WTOP - ZERO >= need && insert_line && delete_line) {
                glitched++;
                WTOP -= need;
                WLINES = WBOT - WTOP + 1;
                p -= need;
                if (p + o == WTOP) {
                    vp->vliny = WTOP;
                    return (WTOP + o);
                }
                vdellin(WTOP, need, -1);
                oldheldech = heldech;
                oldhold = hold;
                hold |= HOLDECH;
            }
            vinslin((vp+1)->vliny, need, l);
            if (glitched) {
                hold = oldhold;
                heldech = oldheldech;
            }
        }
    } else
        vp[1].vliny = vp[0].vliny + vp->vdepth;
    return (p + o);
}

/*
 * Insert cnt blank lines before line p,
 * logically and (if supported) physically.
 */
void
vinslin(int p, int cnt, int l)
{
    int i;
    bool could = 1;

#ifdef ADEBUG
    if (trace)
        tfixnl(), fprintf(trace, "vinslin(%d, %d, %d)\n", p, cnt, l);
#endif
    if (p + cnt > WBOT && clr_eos) {
        /*
         * Really quick -- clear to end of screen.
         */
        cnt = WECHO + 1 - p;
        vgoto(p, 0), vputp(clr_eos, cnt);
        vclrech(1);
        vadjAL(p, cnt);
    } else if (scroll_reverse && p == WTOP && costSR < costAL) {
        /*
         * Use reverse scroll mode of the terminal, at
         * the top of the window.  Reverse linefeed works
         * too, since we only use it from line WTOP.
         */
        for (i = cnt; i > 0; i--) {
            vgoto(p, 0), vputp(scroll_reverse, 0);
            if (i > 1 && (hold & HOLDAT) == 0)
                putchar('@');
            /*
             * If we are at the top of the screen, and the
             * terminal retains display above, then we
             * should try to clear to end of line.
             * Have to use clr_eol since we don't remember what is
             * actually on the line.
             */
            if (clr_eol && (memory_above || p != 0))
                vputp(clr_eol, 1);
        }
        vadjAL(p, cnt);
    } else if (insert_line) {
        /*
         * Use insert line.
         */
        vgoto(p, 0);
        if (parm_insert_line && (cnt>1 || *insert_line==0)) {
            /* insert cnt lines.  Should do @'s too. */
            vputp(tparm(parm_insert_line, cnt, p), WECHO+1-p);
        }
        else if (change_scroll_region && *insert_line==0) {
            /* vt100 change scrolling region to fake insert_line */
            vputp(save_cursor, 1);
            vputp(tparm(change_scroll_region, p, lines-1), 1);
            vputp(restore_cursor, 1);   /* change_scroll_region homes stupid cursor */
            for (i=cnt; i>0; i--)
                vputp(scroll_reverse, 1);   /* should do @'s */
            vputp(tparm(change_scroll_region, 0, lines-1), 1);
            vputp(restore_cursor, 1);   /* Once again put it back */
        }
        else {
            vputp(insert_line, WECHO + 1 - p);
            for (i = cnt - 1; i > 0; i--) {
                vgoto(outline+1, 0);
                vputp(insert_line, WECHO + 1 - outline);
                if ((hold & HOLDAT) == 0)
                    putchar('@');
            }
        }
        vadjAL(p, cnt);
    } else
        could = 0;
    vopenup(cnt, could, l);
}

/*
 * Logically open up after line l, cnt of them.
 * We need to know if it was done ``physically'' since in this
 * case we accept what the hardware gives us.  If we have to do
 * it ourselves (brute force) we will squish out @ lines in the process
 * if this will save us work.
 */
void
vopenup(int cnt, bool could, int l)
{
    struct vlinfo *vc = &vlinfo[l + 1];
    struct vlinfo *ve = &vlinfo[vcnt];

#ifdef ADEBUG
    if (trace)
        tfixnl(), fprintf(trace, "vopenup(%d, %d, %d)\n", cnt, could, l);
#endif
    if (could)
        /*
         * This will push @ lines down the screen,
         * just as the hardware did.  Since the default
         * for intelligent terminals is to never have @
         * lines on the screen, this should never happen,
         * and the code makes no special effort to be nice in this
         * case, e.g. squishing out the @ lines by delete lines
         * before doing append lines.
         */
        for (; vc <= ve; vc++)
            vc->vliny += cnt;
    else {
        /*
         * Will have to clean up brute force eventually,
         * so push the line data around as little as possible.
         */
        vc->vliny += cnt, vc->vflags |= VDIRT;
        while (vc < ve) {
            int i = vc->vliny + vc->vdepth;

            vc++;
            if (i <= vc->vliny)
                break;
            vc->vliny = i, vc->vflags |= VDIRT;
        }
    }
    vscrap();
}

/*
 * Adjust data structure internally to account for insertion of
 * blank lines on the screen.
 */
void
vadjAL(int p, int cnt)
{
    wchar_t *tlines[TUBELINES];
    int from, to;

#ifdef ADEBUG
    if (trace)
        tfixnl(), fprintf(trace, "vadjal(%d, %d)\n", p, cnt);
#endif
    copy(tlines, vtube, sizeof vtube);  /*SASSIGN*/
    for (from = p, to = p + cnt; to <= WECHO; from++, to++)
        vtube[to] = tlines[from];
    for (to = p; from <= WECHO; from++, to++) {
        vtube[to] = tlines[from];
        vclrbyte(vtube[to], WCOLS);
    }
    /*
     * Have to clear the echo area since its contents aren't
     * necessarily consistent with the rest of the display.
     */
    vclrech(0);
}

/*
 * Roll the screen up logically and physically
 * so that line dl is the bottom line on the screen.
 */
void
vrollup(int dl)
{
    int cnt;
    int dc = destcol;

#ifdef ADEBUG
    if (trace)
        tfixnl(), fprintf(trace, "vrollup(%d)\n", dl);
#endif
    cnt = dl - (splitw ? WECHO : WBOT);
    if (splitw && (state == VISUAL || state == CRTOPEN))
        holdupd = 1;
    vmoveitup(cnt, 1);
    vscroll(cnt);
    destline = dl - cnt, destcol = dc;
}

void
vup1(void)
{

    vrollup(WBOT + 1);
}

/*
 * Scroll the screen up cnt lines physically.
 * If doclr is true, do a clear eol if the terminal
 * has standout (to prevent it from scrolling up)
 */
void
vmoveitup(int cnt, bool doclr)
{

    if (cnt == 0)
        return;
#ifdef ADEBUG
    if (trace)
        tfixnl(), fprintf(trace, "vmoveitup(%d)\n", cnt);
#endif
    if (doclr)
        vclrech(0);
    if (scroll_forward) {
        destline = WECHO;
        destcol = (NONL ? 0 : outcol % WCOLS);
        fgoto();
        while (cnt > 0)
            vputp(scroll_forward, 0), cnt--;
    }
    else {
        destline = WECHO + cnt;
        destcol = (NONL ? 0 : outcol % WCOLS);
        fgoto();
        if (state == ONEOPEN || state == HARDOPEN) {
            outline = destline = 0;
            vclrbyte(vtube[0], WCOLS);
        }
    }
    /* Get rid of line we just rolled up */
    if (doclr && memory_below && clr_eol)
        vclrech(0);
}

/*
 * Scroll the screen up cnt lines logically.
 */
void
vscroll(int cnt)
{
    int from, to;
    wchar_t *tlines[TUBELINES];

#ifdef ADEBUG
    if (trace)
        fprintf(trace, "vscroll(%d)\n", cnt);
#endif
    if (cnt < 0 || cnt > TUBELINES)
        error(gettext("Internal error: vscroll"));
    if (cnt == 0)
        return;
    copy(tlines, vtube, sizeof vtube);
    for (to = ZERO, from = ZERO + cnt; to <= WECHO - cnt; to++, from++)
        vtube[to] = tlines[from];
    for (from = ZERO; to <= WECHO; to++, from++) {
        vtube[to] = tlines[from];
        vclrbyte(vtube[to], WCOLS);
    }
    for (from = 0; from <= vcnt; from++)
        LINE(from) -= cnt;
}

/*
 * Discard logical lines due to physical wandering off the screen.
 */
void
vscrap(void)
{
    int i, j;

#ifdef ADEBUG
    if (trace)
        tfixnl(), fprintf(trace, "vscrap\n"), tvliny();
#endif
    if (splitw)
        return;
    if (vcnt && WBOT != WECHO && LINE(0) < WTOP && LINE(0) >= ZERO) {
        WTOP = LINE(0);
        WLINES = WBOT - WTOP + 1;
    }
    for (j = 0; j < vcnt; j++)
        if (LINE(j) >= WTOP) {
            if (j == 0)
                break;
            /*
             * Discard the first j physical lines off the top.
             */
            vcnt -= j, vcline -= j;
            for (i = 0; i <= vcnt; i++)
                vlcopy(vlinfo[i], vlinfo[i + j]);
            break;
        }
    /*
     * Discard lines off the bottom.
     */
    if (vcnt) {
        for (j = 0; j <= vcnt; j++)
            if (LINE(j) > WBOT || LINE(j) + DEPTH(j) - 1 > WBOT) {
                vcnt = j;
                break;
            }
        if (vcnt == 0)
            LASTLINE = 0;
        else
            LASTLINE = LINE(vcnt-1) + DEPTH(vcnt-1);
    }
#ifdef ADEBUG
    if (trace)
        tvliny();
#endif
    /*
     * May have no lines!
     */
}

/*
 * Repaint the screen, with cursor at curs, aftern an arbitrary change.
 * Handle notification on large changes.
 */
void
vrepaint(unsigned char *curs)
{

    wdot = NOLINE;
    /*
     * In open want to notify first.
     */
    noteit(0);
    vscrap();

    /*
     * Deal with a totally useless display.
     */
    if (vcnt == 0 || vcline < 0 || vcline > vcnt || holdupd && state != VISUAL) {
        line *odol = dol;

        vcnt = 0;
        if (holdupd)
            if (state == VISUAL)
                (void)peekkey();
            else
                vup1();
        holdupd = 0;
        if (odol == zero)
            fixzero();
        vcontext(dot, '.');
        noteit(1);
        if (noteit(1) == 0 && odol == zero) {
            CATCH
                error(gettext("No lines in buffer"));
            ENDCATCH
            linebuf[0] = 0;
            splitw = 0;
        }
        vnline(curs);
        return;
    }

    /*
     * Have some useful displayed text; refresh it.
     */
    getDOT();

    /*
     * This is for boundary conditions in open mode.
     */
    if (FLAGS(0) & VDIRT)
        vsync(WTOP);

    /*
     * If the current line is after the last displayed line
     * or the bottom of the screen, then special effort is needed
     * to get it on the screen.  We first try a redraw at the
     * last line on the screen, hoping it will fill in where @
     * lines are now.  If this doesn't work, then roll it onto
     * the screen.
     */
    if (vcline >= vcnt || LINE(vcline) > WBOT) {
        short oldhold = hold;
        hold |= HOLDAT, vredraw(LASTLINE), hold = oldhold;
        if (vcline >= vcnt) {
            int i = vcline - vcnt + 1;

            dot -= i;
            vcline -= i;
            vroll(i);
        } else
            vsyncCL();
    } else
        vsync(vcline > 0 ? LINE(vcline - 1) : WTOP);

    /*
     * Notification on large change for visual
     * has to be done last or we may lose
     * the echo area with redisplay.
     */
    noteit(1);

    /*
     * Finally.  Move the cursor onto the current line.
     */
    vnline(curs);
}

/*
 * Fully cleanup the screen, leaving no @ lines except at end when
 * line after last won't completely fit.  The routine vsync is
 * more conservative and much less work on dumb terminals.
 */
void
vredraw(int p)
{
    int l;
    line *tp;
    unsigned char temp[LBSIZE];
    bool anydl = 0;
    short oldhold = hold;

#ifdef ADEBUG
    if (trace)
        tfixnl(), fprintf(trace, "vredraw(%d)\n", p), tvliny();
#endif
    if (holdupd) {
        holdupd = 3;
        return;
    }
    if (state == HARDOPEN || splitw)
        return;
    if (p < 0 /* || p > WECHO */)
        error(gettext("Internal error: vredraw"));

    /*
     * Trim the ragged edges (lines which are off the screen but
     * not yet logically discarded), save the current line, and
     * search for first logical line affected by the redraw.
     */
    vscrap();
    CP(temp, linebuf);
    l = 0;
    tp = dot - vcline;
    if (vcnt == 0)
        LINE(0) = WTOP;
    while (l < vcnt && LINE(l) < p)
        l++, tp++;

    /*
     * We hold off echo area clearing during the redraw in deference
     * to a final clear of the echo area at the end if appropriate.
     */
    heldech = 0;
    hold |= HOLDECH;
    for (; l < vcnt && Peekkey != ATTN; l++) {
        if (l == vcline)
            strcLIN(temp);
        else
            getaline(*tp);

        /*
         * Delete junk between displayed lines.
         */
        if (LINE(l) != LINE(l + 1) && LINE(l) != p) {
            if (anydl == 0 && memory_below && clr_eos) {
                hold = oldhold;
                vclrech(0);
                anydl = 1;
                hold |= HOLDECH;
                heldech = 0;
            }
            vdellin(p, LINE(l) - p, l);
        }

        /*
         * If line image is not know to be up to date, then
         * redisplay it;  else just skip onward.
         */
        LINE(l) = p;
        if (FLAGS(l) & VDIRT) {
            DEPTH(l) = vdepth();
            if (l != vcline && p + DEPTH(l) - 1 > WBOT) {
                vscrap();
                break;
            }
            FLAGS(l) &= ~VDIRT;
            (void) vreopen(p, lineno(tp), l);
            p = LINE(l) + DEPTH(l);
        } else
            p += DEPTH(l);
        tp++;
    }

    /*
     * That takes care of lines which were already partially displayed.
     * Now try to fill the rest of the screen with text.
     */
    if (state == VISUAL && p <= WBOT) {
        int ovcline = vcline;

        vcline = l;
        for (; tp <= dol && Peekkey != ATTN; tp++) {
            getaline(*tp);
            if (p + vdepth() - 1 > WBOT)
                break;
            vopen(tp, p);
            p += DEPTH(vcline);
            vcline++;
        }
        vcline = ovcline;
    }

    /*
     * That's all the text we can get on.
     * Now rest of lines (if any) get either a ~ if they
     * are past end of file, or an @ if the next line won't fit.
     */
    for (; p <= WBOT && Peekkey != ATTN; p++)
        vclrlin(p, tp);
    strcLIN(temp);
    hold = oldhold;
    if (heldech)
        vclrech(0);
#ifdef ADEBUG
    if (trace)
        tvliny();
#endif
}

/*
 * Do the real work in deleting cnt lines starting at line p from
 * the display.  First affected line is line l.
 */
void
vdellin(int p, int cnt, int l)
{
    int i;

    if (cnt == 0)
        return;
    if (delete_line == NOSTR || cnt < 0) {
        /*
         * Can't do it; just remember that line l is munged.
         */
        FLAGS(l) |= VDIRT;
        return;
    }
#ifdef ADEBUG
    if (trace)
        tfixnl(), fprintf(trace, "vdellin(%d, %d, %d)\n", p, cnt, l);
#endif
    /*
     * Send the deletes to the screen and then adjust logical
     * and physical internal data structures.
     */
    vgoto(p, 0);
    if (parm_delete_line && (cnt>1 || *delete_line==0)) {
        vputp(tparm(parm_delete_line, cnt, p), WECHO-p);
    }
    else if (change_scroll_region && *delete_line==0) {
        /* vt100: fake delete_line by changing scrolling region */
        vputp(save_cursor, 1);  /* Save since change_scroll_region homes stupid cursor */
        vputp(tparm(change_scroll_region, p, lines-1), 1);
        vputp(tparm(cursor_address, lines-1, 0), 1);/* Go to lower left corner */
        for (i=0; i<cnt; i++)       /* .. and scroll cnt times */
            (void) putch('\n'); /* should check NL too */
        vputp(tparm(change_scroll_region, 0, lines-1), 1);/* restore scrolling region */
        vputp(restore_cursor, 1);           /* put cursor back */
    }
    else {
        for (i = 0; i < cnt; i++)
            vputp(delete_line, WECHO - p);
    }
    vadjDL(p, cnt);
    vcloseup(l, cnt);
}
/*
 * Adjust internal physical screen image to account for deleted lines.
 */
void
vadjDL(int p, int cnt)
{
    wchar_t *tlines[TUBELINES];
    int from, to;

#ifdef ADEBUG
    if (trace)
        tfixnl(), fprintf(trace, "vadjDL(%d, %d)\n", p, cnt);
#endif
    /*
     * Would like to use structured assignment but early
     * v7 compiler (released with phototypesetter for v6)
     * can't hack it.
     */
    copy(tlines, vtube, sizeof vtube);  /*SASSIGN*/
    for (from = p + cnt, to = p; from <= WECHO; from++, to++)
        vtube[to] = tlines[from];
    for (from = p; to <= WECHO; from++, to++) {
        vtube[to] = tlines[from];
        vclrbyte(vtube[to], WCOLS);
    }
}
/*
 * Sync the screen, like redraw but more lazy and willing to leave
 * @ lines on the screen.  VsyncCL syncs starting at the current line.
 * In any case, if the redraw option is set then all syncs map to redraws
 * as if vsync didn't exist.
 */
void
vsyncCL(void)
{

    vsync(LINE(vcline));
}

void
vsync(int p)
{

    if (value(vi_REDRAW))
        vredraw(p);
    else
        vsync1(p);
}

/*
 * The guts of a sync.  Similar to redraw but
 * just less ambitious.
 */
void
vsync1(int p)
{
    int l;
    unsigned char temp[LBSIZE];
    struct vlinfo *vp = &vlinfo[0];
    short oldhold = hold;

#ifdef ADEBUG
    if (trace)
        tfixnl(), fprintf(trace, "vsync1(%d)\n", p), tvliny();
#endif
    if (holdupd) {
        if (holdupd < 3)
            holdupd = 2;
        return;
    }
    if (state == HARDOPEN || splitw)
        return;
    vscrap();
    CP(temp, linebuf);
    if (vcnt == 0)
        LINE(0) = WTOP;
    l = 0;
    while (l < vcnt && vp->vliny < p)
        l++, vp++;
    heldech = 0;
    hold |= HOLDECH;
    while (p <= WBOT && Peekkey != ATTN) {
        /*
         * Want to put a line here if not in visual and first line
         * or if there are lies left and this line starts before
         * the current line, or if this line is piled under the
         * next line (vreplace does this and we undo it).
         */
        if (l == 0 && state != VISUAL ||
            (l < vcnt && (vp->vliny <= p || vp[0].vliny == vp[1].vliny))) {
            if (l == 0 || vp->vliny < p || (vp->vflags & VDIRT)) {
                if (l == vcline)
                    strcLIN(temp);
                else
                    getaline(dot[l - vcline]);
                /*
                 * Be careful that a long line doesn't cause the
                 * screen to shoot up.
                 */
                if (l != vcline && (vp->vflags & VDIRT)) {
                    vp->vdepth = vdepth();
                    vp->vflags &= ~VDIRT;
                    if (p + vp->vdepth - 1 > WBOT)
                        break;
                }
                (void) vreopen(p, lineDOT() + (l - vcline), l);
            }
            p = vp->vliny + vp->vdepth;
            vp++;
            l++;
        } else
            /*
             * A physical line between logical lines,
             * so we settle for an @ at the beginning.
             */
            vclrlin(p, dot + (l - vcline)), p++;
    }
    strcLIN(temp);
    hold = oldhold;
    if (heldech)
        vclrech(0);
}

/*
 * Subtract (logically) cnt physical lines from the
 * displayed position of lines starting with line l.
 */
void
vcloseup(int l, int cnt)
{
    int i;

#ifdef ADEBUG
    if (trace)
        tfixnl(), fprintf(trace, "vcloseup(%d, %d)\n", l, cnt);
#endif
    for (i = l + 1; i <= vcnt; i++)
        LINE(i) -= cnt;
}

/*
 * Workhorse for rearranging line descriptors on changes.
 * The idea here is that, starting with line l, cnt lines
 * have been replaced with newcnt lines.  All of these may
 * be ridiculous, i.e. l may be -1000, cnt 50 and newcnt 0,
 * since we may be called from an undo after the screen has
 * moved a lot.  Thus we have to be careful.
 *
 * Many boundary conditions here.
 */
void
vreplace(int l, int cnt, int newcnt)
{
    int from, to, i;
    bool savenote = 0;

#ifdef ADEBUG
    if (trace) {
        tfixnl(), fprintf(trace, "vreplace(%d, %d, %d)\n", l, cnt, newcnt);
        tvliny();
    }
#endif
    if (l >= vcnt)
        return;
    if (l < 0) {
        if (l + cnt < 0) {
            /*
             * Nothing on the screen is relevant.
             * Settle for redrawing from scratch (later).
             */
            vcnt = 0;
            return;
        }
        /*
         * Normalize l to top of screen; the add is
         * really a subtract from cnt since l is negative.
         */
        cnt += l;
        l = 0;

        /*
         * Unseen lines were affected so notify (later).
         */
        savenote++;
    }

    /*
     * These shouldn't happen
     * but would cause great havoc.
     */
    if (cnt < 0)
        cnt = 0;
    if (newcnt < 0)
        newcnt = 0;

    /*
     * Surely worthy of note if more than report
     * lines were changed.
     */
    if (cnt > value(vi_REPORT) || newcnt > value(vi_REPORT))
        savenote++;

    /*
     * Same number of lines affected as on screen, and we
     * can insert and delete lines.  Thus we just type
     * over them, since otherwise we will push them
     * slowly off the screen, a clear lose.
     */
    if (cnt == newcnt || vcnt - l == newcnt && insert_line && delete_line) {
        if (cnt > 1 && l + cnt > vcnt)
            savenote++;
        vdirty(l, newcnt);
    } else {
        /*
         * Lines are going away, squish them out.
         */
        if (cnt > 0) {
            /*
             * If non-displayed lines went away,
             * always notify.
             */
            if (cnt > 1 && l + cnt > vcnt)
                savenote++;
            if (l + cnt >= vcnt)
                cnt = vcnt - l;
            else
                for (from = l + cnt, to = l; from <= vcnt; to++, from++)
                    vlcopy(vlinfo[to], vlinfo[from]);
            vcnt -= cnt;
        }
        /*
         * Open up space for new lines appearing.
         * All new lines are piled in the same place,
         * and will be unpiled by vredraw/vsync, which
         * inserts lines in front as it unpiles.
         */
        if (newcnt > 0) {
            /*
             * Newlines are appearing which may not show,
             * so notify (this is only approximately correct
             * when long lines are present).
             */
            if (newcnt > 1 && l + newcnt > vcnt + 1)
                savenote++;

            /*
             * If there will be more lines than fit, then
             * just throw way the rest of the stuff on the screen.
             */
            if (l + newcnt > WBOT && insert_line && delete_line) {
                vcnt = l;
                goto skip;
            }
            from = vcnt, to = vcnt + newcnt;
            i = TUBELINES - to;
            if (i < 0)
                from += i, to += i;
            vcnt = to;
            for (; from >= l; from--, to--)
                vlcopy(vlinfo[to], vlinfo[from]);
            for (from = to + 1, to = l; to < l + newcnt && to <= WBOT + 1; to++) {
                LINE(to) = LINE(from);
                DEPTH(to) = 0;
                FLAGS(to) = VDIRT;
            }
        }
    }
skip:
    if (Pline == numbline && cnt != newcnt)
        /*
         * When lines positions are shifted, the numbers
         * will be wrong.
         */
        vdirty(l, WECHO);
    if (!savenote)
        notecnt = 0;
#ifdef ADEBUG
    if (trace)
        tvliny();
#endif
}

/*
 * Start harcopy open.
 * Print an image of the line to the left of the cursor
 * under the full print of the line and position the cursor.
 * If we are in a scroll ^D within hardcopy open then all this
 * is suppressed.
 */
void
sethard(void)
{

    if (state == VISUAL)
        return;
    rubble = 0;
    state = HARDOPEN;
    if (hold & HOLDROL)
        return;
    vup1();
    LINE(0) = WBOT;
    if (Pline == numbline)
        vgoto(WBOT, 0), viprintf("%6d  ", lineDOT());
}

/*
 * Mark the lines starting at base for i lines
 * as dirty so that they will be checked for correct
 * display at next sync/redraw.
 */
void
vdirty(int base, int i)
{
    int l;

    for (l = base; l < vcnt; l++) {
        if (--i < 0)
            return;
        FLAGS(l) |= VDIRT;
    }
}