Return to refresh.c CVS log

Up to [cvs.NetBSD.org] / src / lib / libcurses

Upgrades the standard NetBSD curses library to provide some
of the SYSV curses facilities.  The added features are the collapsing
of arrow and function keysequences (as defined by termcap for the
terminal) into symbolic code returns thus relieving the application of
recognising multi-character key sequences.  Other features are the
capability to perform a timed wait for a key (good for when you are
not sure if there is a keypress ready or not) and the capability for
turning off the inter-key timeout when assembling multi-character
function keys.

this work was done by Julian Coleman <J.D.Coleman@newcastle.ac.uk>
and blymn@baea.com.au (Brett Lymn).  i'm just integrating it.  thanks
HEAPS guys!

/*	$NetBSD: refresh.c,v 1.11 1999/04/13 14:08:18 mrg Exp $	*/

/*
 * Copyright (c) 1981, 1993, 1994
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)refresh.c	8.7 (Berkeley) 8/13/94";
#else
__RCSID("$NetBSD: refresh.c,v 1.11 1999/04/13 14:08:18 mrg Exp $");
#endif
#endif				/* not lint */

#include <string.h>

#include "curses.h"

static int curwin;
static short ly, lx;

static void	domvcur __P((int, int, int, int));
static int	makech __P((WINDOW *, int));
static void	quickch __P((WINDOW *));
static void	scrolln __P((WINDOW *, int, int, int, int, int));

/*
 * wrefresh --
 *	Make the current screen look like "win" over the area coverd by
 *	win.
 */
int
wrefresh(win)
	WINDOW *win;
{
	__LINE *wlp;
	int	retval;
	short	wy;
	int	dnum;

	/* Check if we need to restart ... */
	if (__endwin) {
		__endwin = 0;
		__restartwin();
	}

	/* Initialize loop parameters. */
	ly = curscr->cury;
	lx = curscr->curx;
	wy = 0;
	curwin = (win == curscr);

	if (!curwin)
		for (wy = 0; wy < win->maxy; wy++) {
			wlp = win->lines[wy];
			if (wlp->flags & __ISDIRTY)
				wlp->hash = __hash((char *) wlp->line,
				    (int) (win->maxx * __LDATASIZE));
		}

	if (win->flags & __CLEAROK || curscr->flags & __CLEAROK || curwin) {
		if ((win->flags & __FULLWIN) || curscr->flags & __CLEAROK) {
			tputs(CL, 0, __cputchar);
			ly = 0;
			lx = 0;
			if (!curwin) {
				curscr->flags &= ~__CLEAROK;
				curscr->cury = 0;
				curscr->curx = 0;
				werase(curscr);
			}
			__touchwin(win);
		}
		win->flags &= ~__CLEAROK;
	}
	if (!CA) {
		if (win->curx != 0)
			putchar('\n');
		if (!curwin)
			werase(curscr);
	}
#ifdef DEBUG
	__CTRACE("wrefresh: (%0.2o): curwin = %d\n", win, curwin);
	__CTRACE("wrefresh: \tfirstch\tlastch\n");
#endif

#ifndef NOQCH
	if ((win->flags & __FULLWIN) && !curwin) {
		/*
		 * Invoke quickch() only if more than a quarter of the lines
		 * in the window are dirty.
		 */
		for (wy = 0, dnum = 0; wy < win->maxy; wy++)
			if (win->lines[wy]->flags & (__ISDIRTY | __FORCEPAINT))
				dnum++;
		if (!__noqch && dnum > (int) win->maxy / 4)
			quickch(win);
	}
#endif

#ifdef DEBUG
	{
		int	i, j;

		__CTRACE("#####################################\n");
		for (i = 0; i < curscr->maxy; i++) {
			__CTRACE("C: %d:", i);
			__CTRACE(" 0x%x \n", curscr->lines[i]->hash);
			for (j = 0; j < curscr->maxx; j++)
				__CTRACE("%c", curscr->lines[i]->line[j].ch);
			__CTRACE("\n");
			for (j = 0; j < curscr->maxx; j++)
				__CTRACE("%x", curscr->lines[i]->line[j].attr);
			__CTRACE("\n");
			__CTRACE("W: %d:", i);
			__CTRACE(" 0x%x \n", win->lines[i]->hash);
			__CTRACE(" 0x%x ", win->lines[i]->flags);
			for (j = 0; j < win->maxx; j++)
				__CTRACE("%c", win->lines[i]->line[j].ch);
			__CTRACE("\n");
			for (j = 0; j < win->maxx; j++)
				__CTRACE("%x", win->lines[i]->line[j].attr);
			__CTRACE("\n");
		}
	}
#endif				/* DEBUG */

	for (wy = 0; wy < win->maxy; wy++) {
#ifdef DEBUG
		__CTRACE("%d\t%d\t%d\n",
		    wy, *win->lines[wy]->firstchp, *win->lines[wy]->lastchp);
#endif
		if (!curwin)
			curscr->lines[wy]->hash = win->lines[wy]->hash;
		if (win->lines[wy]->flags & (__ISDIRTY | __FORCEPAINT)) {
			if (makech(win, wy) == ERR)
				return (ERR);
			else {
				if (*win->lines[wy]->firstchp >= win->ch_off)
					*win->lines[wy]->firstchp = win->maxx +
					    win->ch_off;
				if (*win->lines[wy]->lastchp < win->maxx +
				    win->ch_off)
					*win->lines[wy]->lastchp = win->ch_off;
				if (*win->lines[wy]->lastchp <
				    *win->lines[wy]->firstchp) {
#ifdef DEBUG
					__CTRACE("wrefresh: line %d notdirty \n", wy);
#endif
					win->lines[wy]->flags &= ~__ISDIRTY;
				}
			}

		}
#ifdef DEBUG
		__CTRACE("\t%d\t%d\n", *win->lines[wy]->firstchp,
		    *win->lines[wy]->lastchp);
#endif
	}

#ifdef DEBUG
	__CTRACE("refresh: ly=%d, lx=%d\n", ly, lx);
#endif

	if (win == curscr)
		domvcur(ly, lx, (int) win->cury, (int) win->curx);
	else {
		if (win->flags & __LEAVEOK) {
			curscr->cury = ly;
			curscr->curx = lx;
			ly -= win->begy;
			lx -= win->begx;
			if (ly >= 0 && ly < win->maxy && lx >= 0 &&
			    lx < win->maxx) {
				win->cury = ly;
				win->curx = lx;
			} else
				win->cury = win->curx = 0;
		} else {
			domvcur(ly, lx, (int) (win->cury + win->begy),
			    (int) (win->curx + win->begx));
			curscr->cury = win->cury + win->begy;
			curscr->curx = win->curx + win->begx;
		}
	}
	retval = OK;

	(void) fflush(stdout);
	return (retval);
}

/*
 * makech --
 *	Make a change on the screen.
 */
static int
makech(win, wy)
	WINDOW *win;
	int	wy;
{
	static __LDATA blank = {' ', 0};
	__LDATA *nsp, *csp, *cp, *cep;
	u_int	force;
	int	clsp, nlsp;	/* Last space in lines. */
	int	lch, wx, y;
	char	*ce;

#ifdef __GNUC__
	nlsp = 0;		/* XXX gcc -Wuninitialized */
#endif
	/* Is the cursor still on the end of the last line? */
	if (wy > 0 && win->lines[wy - 1]->flags & __ISPASTEOL) {
		domvcur(ly, lx, ly + 1, 0);
		ly++;
		lx = 0;
	}
	wx = *win->lines[wy]->firstchp - win->ch_off;
	if (wx < 0)
		wx = 0;
	else
		if (wx >= win->maxx)
			return (OK);
	lch = *win->lines[wy]->lastchp - win->ch_off;
	if (lch < 0)
		return (OK);
	else
		if (lch >= (int) win->maxx)
			lch = win->maxx - 1;
	y = wy + win->begy;

	if (curwin)
		csp = &blank;
	else
		csp = &curscr->lines[wy + win->begy]->line[wx + win->begx];

	nsp = &win->lines[wy]->line[wx];
	force = win->lines[wy]->flags & __FORCEPAINT;
	win->lines[wy]->flags &= ~__FORCEPAINT;
	if (CE && !curwin) {
		for (cp = &win->lines[wy]->line[win->maxx - 1];
		    cp->ch == ' ' && cp->attr == 0; cp--)
			if (cp <= win->lines[wy]->line)
				break;
		nlsp = cp - win->lines[wy]->line;
	}
	if (!curwin)
		ce = CE;
	else
		ce = NULL;

	if (force) {
		if (CM)
			tputs(tgoto(CM, lx, ly), 0, __cputchar);
		else {
			tputs(HO, 0, __cputchar);
			__mvcur(0, 0, ly, lx, 1);
		}
	}

	while (wx <= lch) {
		if (!force && memcmp(nsp, csp, sizeof(__LDATA)) == 0) {
			if (wx <= lch) {
				while (wx <= lch &&
				    memcmp(nsp, csp, sizeof(__LDATA)) == 0) {
					nsp++;
					if (!curwin)
						++csp;
					++wx;
				}
				continue;
			}
			break;
		}
		domvcur(ly, lx, y, (int) (wx + win->begx));

#ifdef DEBUG
		__CTRACE("makech: 1: wx = %d, ly= %d, lx = %d, newy = %d, newx = %d, force =%d\n",
		    wx, ly, lx, y, wx + win->begx, force);
#endif
		ly = y;
		lx = wx + win->begx;
		while ((force || memcmp(nsp, csp, sizeof(__LDATA)) != 0)
		    && wx <= lch) {

			if (ce != NULL &&
			    win->maxx + win->begx == curscr->maxx &&
			    wx >= nlsp && nsp->ch == ' ' && nsp->attr == 0) {
				/* Check for clear to end-of-line. */
				cep = &curscr->lines[wy]->line[win->maxx - 1];
				while (cep->ch == ' ' && cep->attr == 0)
					if (cep-- <= csp)
						break;
				clsp = cep - curscr->lines[wy]->line -
				    win->begx * __LDATASIZE;
#ifdef DEBUG
				__CTRACE("makech: clsp = %d, nlsp = %d\n", clsp, nlsp);
#endif
				if ((clsp - nlsp >= strlen(CE)
				    && clsp < win->maxx * __LDATASIZE) ||
				    wy == win->maxy - 1) {
					if (curscr->flags & __WSTANDOUT) {
						tputs(SE, 0, __cputchar);
						curscr->flags &= ~__WSTANDOUT;
						if (*SE == *UE) {
							curscr->flags &=
						    ~__WUNDERSCORE;
						}
						if (*SE == *ME) {
							curscr->flags &=
						    ~__WATTRIBUTES;
						}
					}
					if (curscr->flags & __WUNDERSCORE) {
						tputs(UE, 0, __cputchar);
						curscr->flags &= ~__WUNDERSCORE;
						if (*UE == *ME) {
							curscr->flags &=
						    ~__WATTRIBUTES;
						}
					}
					if (curscr->flags & __WATTRIBUTES) {
						tputs(UE, 0, __cputchar);
						curscr->flags &= ~__WATTRIBUTES;
					}
					tputs(CE, 0, __cputchar);
					lx = wx + win->begx;
					while (wx++ <= clsp) {
						csp->ch = ' ';
						csp->attr = 0;
						csp++;
					}
					return (OK);
				}
				ce = NULL;
			}

			/*
			 * Unset attributes as appropriate.  Unset first
			 * so that the relevant attributes can be reset
			 * (because termcap 'me' unsets 'mb', 'md', 'mh',
			 * 'mk', 'mp' and 'mr').  However, 'me' might also
			 * do 'se' and/or 'ue'.  If so, we change the
			 * screen flags to reflect this.
			 */
			if ((!(nsp->attr & __BLINK) &&
			    curscr->flags & __WBLINK) ||
			    (!(nsp->attr & __BOLD) &&
			    curscr->flags & __WBOLD) ||
			    (!(nsp->attr & __DIM) &&
			    curscr->flags & __WDIM) ||
			    (!(nsp->attr & __BLANK) &&
			    curscr->flags & __WBLANK) ||
			    (!(nsp->attr & __PROTECT) &&
			    curscr->flags & __WPROTECT) ||
			    (!(nsp->attr & __REVERSE) &&
			    curscr->flags & __WREVERSE) ||
			    (!(nsp->attr & __BOLD) &&
			    curscr->flags & __WBOLD)) {
				if (ME != NULL) {
					tputs(ME, 0, __cputchar);
					curscr->flags &= ~__WATTRIBUTES;
					if (*ME == *SE) {
						curscr->flags &= ~__WSTANDOUT;
					}
					if (*ME == *UE) {
						curscr->flags &= ~__WUNDERSCORE;
					}
				}
			}

			/*
			 * Exit underscore mode if appropriate.
			 *
			 * Note: check to see if we also turn off attributes
			 * and standout.
			 */
			if (!(nsp->attr & __UNDERSCORE) &&
			    curscr->flags & __WUNDERSCORE &&
			    UE != NULL) {
				tputs(UE, 0, __cputchar);
				curscr->flags &= ~__WUNDERSCORE;
				if (*UE == *ME) {
					curscr->flags &= ~__WATTRIBUTES;
				}
				if (*UE == *SE) {
					curscr->flags &= ~__WSTANDOUT;
				}
			}

			/*
			 * Enter/exit standout mode as appropriate.
			 * XXX
			 * Should use UC if SO/SE not available.
			 *
			 * Note: check to see if we also turn off attributes
			 * and underscore.  If we have turned off underscore
			 * and it should be on, turn it back on.
			 */
			if (nsp->attr & __STANDOUT) {
				if (!(curscr->flags & __WSTANDOUT) &&
				    SO != NULL && SE != NULL) {
					tputs(SO, 0, __cputchar);
					curscr->flags |= __WSTANDOUT;
				}
			} else {
				if (curscr->flags & __WSTANDOUT &&
				    SE != NULL) {
					tputs(SE, 0, __cputchar);
					curscr->flags &= ~__WSTANDOUT;
					if (*SE == *ME) {
						curscr->flags &= ~__WATTRIBUTES;
					}
					if (*SE == *UE) {
						curscr->flags &= ~__WUNDERSCORE;
					}
				}
			}

			/*
			 * Enter underscore mode if appropriate.
			 * XXX
			 * Should use UC if US/UE not available.
			 *
			 * Note: check to see if we also turn off attributes
			 * and standout.
			 */
			if (nsp->attr & __UNDERSCORE &&
			    !(curscr->flags & __WUNDERSCORE) &&
			    US != NULL && UE != NULL) {
				tputs(US, 0, __cputchar);
				curscr->flags |= __WUNDERSCORE;
			}

			/*
			 * Set other attributes as appropriate.
			 */
			if (nsp->attr & __REVERSE) {
				if (!(curscr->flags & __WREVERSE) &&
				    MR != NULL && ME != NULL) {
					tputs(MR, 0, __cputchar);
					curscr->flags |= __WREVERSE;
				}
			}
			if (nsp->attr & __BLINK) {
				if (!(curscr->flags & __WBLINK) &&
				    MB != NULL && ME != NULL) {
					tputs(MB, 0, __cputchar);
					curscr->flags |= __WBLINK;
				}
			}
			if (nsp->attr & __DIM) {
				if (!(curscr->flags & __WDIM) &&
				    MH != NULL && ME != NULL) {
					tputs(MH, 0, __cputchar);
					curscr->flags |= __WDIM;
				}
			}
			if (nsp->attr & __BOLD) {
				if (!(curscr->flags & __WBOLD) &&
				    MD != NULL && ME != NULL) {
					tputs(MD, 0, __cputchar);
					curscr->flags |= __WBOLD;
				}
			}
			if (nsp->attr & __BLANK) {
				if (!(curscr->flags & __WBLANK) &&
				    MK != NULL && ME != NULL) {
					tputs(MK, 0, __cputchar);
					curscr->flags |= __WBLANK;
				}
			}
			if (nsp->attr & __PROTECT) {
				if (!(curscr->flags & __WPROTECT) &&
				    MP != NULL && ME != NULL) {
					tputs(MP, 0, __cputchar);
					curscr->flags |= __WPROTECT;
				}
			}

			wx++;
			if (wx >= win->maxx && wy == win->maxy - 1 && !curwin)
				if (win->flags & __SCROLLOK) {
					if (curscr->flags & __WSTANDOUT
					    && win->flags & __ENDLINE)
						if (!MS) {
							tputs(SE, 0,
							    __cputchar);
							curscr->flags &=
							    ~__WSTANDOUT;
						}
					if (curscr->flags & __WUNDERSCORE
					    && win->flags & __ENDLINE)
						if (!MS) {
							tputs(UE, 0,
							    __cputchar);
							curscr->flags &=
							    ~__WUNDERSCORE;
						}
					if (curscr->flags & __WATTRIBUTES
					    && win->flags & __ENDLINE)
						if (!MS) {
							tputs(ME, 0,
							    __cputchar);
							curscr->flags &=
							    ~__WATTRIBUTES;
						}
					if (!(win->flags & __SCROLLWIN)) {
						if (!curwin) {
							csp->attr = nsp->attr;
							putchar(csp->ch = nsp->ch);
						} else
							putchar(nsp->ch);
					}
					if (wx + win->begx < curscr->maxx) {
						domvcur(ly, (int) (wx + win->begx),
						    (int) (win->begy + win->maxy - 1),
						    (int) (win->begx + win->maxx - 1));
					}
					ly = win->begy + win->maxy - 1;
					lx = win->begx + win->maxx - 1;
					return (OK);
				}
			if (wx < win->maxx || wy < win->maxy - 1 ||
			    !(win->flags & __SCROLLWIN)) {
				if (!curwin) {
					csp->attr = nsp->attr;
					putchar(csp->ch = nsp->ch);
					csp++;
				} else
					putchar(nsp->ch);
			}
#ifdef DEBUG
			__CTRACE("makech: putchar(%c)\n", nsp->ch & 0177);
#endif
			if (UC && ((nsp->attr & __STANDOUT) ||
			    (nsp->attr & __UNDERSCORE))) {
				putchar('\b');
				tputs(UC, 0, __cputchar);
			}
			nsp++;
#ifdef DEBUG
			__CTRACE("makech: 2: wx = %d, lx = %d\n", wx, lx);
#endif
		}
		if (lx == wx + win->begx)	/* If no change. */
			break;
		lx = wx + win->begx;
		if (lx >= COLS && AM)
			lx = COLS - 1;
		else
			if (wx >= win->maxx) {
				domvcur(ly, lx, ly, (int) (win->maxx + win->begx - 1));
				lx = win->maxx + win->begx - 1;
			}
#ifdef DEBUG
		__CTRACE("makech: 3: wx = %d, lx = %d\n", wx, lx);
#endif
	}

	/* Don't leave the screen in standout mode. */
	if (curscr->flags & __WSTANDOUT) {
		tputs(SE, 0, __cputchar);
		curscr->flags &= ~__WSTANDOUT;
	}
	/* Don't leave the screen in underscore mode. */
	if (curscr->flags & __WUNDERSCORE) {
		tputs(UE, 0, __cputchar);
		curscr->flags &= ~__WUNDERSCORE;
	}
	/* Don't leave the screen with attributes set. */
	if (curscr->flags & __WATTRIBUTES) {
		tputs(ME, 0, __cputchar);
		curscr->flags &= ~__WATTRIBUTES;
	}
	return (OK);
}

/*
 * domvcur --
 *	Do a mvcur, leaving standout and attribute modes if necessary.
 */
static void
domvcur(oy, ox, ny, nx)
	int	oy, ox, ny, nx;
{
	if (curscr->flags & __WSTANDOUT && !MS) {
		tputs(SE, 0, __cputchar);
		curscr->flags &= ~__WSTANDOUT;
	}
	if (curscr->flags & __WUNDERSCORE && !MS) {
		tputs(UE, 0, __cputchar);
		curscr->flags &= ~__WUNDERSCORE;
	}
	if (curscr->flags & __WATTRIBUTES && !MS) {
		tputs(ME, 0, __cputchar);
		curscr->flags &= ~__WATTRIBUTES;
	}

	__mvcur(oy, ox, ny, nx, 1);
}

/*
 * Quickch() attempts to detect a pattern in the change of the window
 * in order to optimize the change, e.g., scroll n lines as opposed to
 * repainting the screen line by line.
 */

static void
quickch(win)
	WINDOW *win;
{
#define THRESH		(int) win->maxy / 4

	__LINE *clp, *tmp1, *tmp2;
	int	bsize, curs, curw, starts, startw, i, j;
	int	n, target, cur_period, bot, top, sc_region;
	__LDATA buf[1024];
	u_int	blank_hash;

#ifdef __GNUC__
	curs = curw = starts = startw = 0;	/* XXX gcc -Wuninitialized */
#endif
	/*
	 * Find how many lines from the top of the screen are unchanged.
	 */
	for (top = 0; top < win->maxy; top++)
		if (win->lines[top]->flags & __FORCEPAINT ||
		    win->lines[top]->hash != curscr->lines[top]->hash
		    || memcmp(win->lines[top]->line,
			curscr->lines[top]->line,
			win->maxx * __LDATASIZE) != 0)
			break;
		else
			win->lines[top]->flags &= ~__ISDIRTY;
	/*
	 * Find how many lines from bottom of screen are unchanged.
	 */
	for (bot = win->maxy - 1; bot >= 0; bot--)
		if (win->lines[bot]->flags & __FORCEPAINT ||
		    win->lines[bot]->hash != curscr->lines[bot]->hash
		    || memcmp(win->lines[bot]->line,
			curscr->lines[bot]->line,
			win->maxx * __LDATASIZE) != 0)
			break;
		else
			win->lines[bot]->flags &= ~__ISDIRTY;

#ifdef NO_JERKINESS
	/*
	 * If we have a bottom unchanged region return.  Scrolling the
	 * bottom region up and then back down causes a screen jitter.
	 * This will increase the number of characters sent to the screen
	 * but it looks better.
	 */
	if (bot < win->maxy - 1)
		return;
#endif				/* NO_JERKINESS */

	/*
	 * Search for the largest block of text not changed.
	 * Invariants of the loop:
	 * - Startw is the index of the beginning of the examined block in win.
	 * - Starts is the index of the beginning of the examined block in
	 *    curscr.
	 * - Curs is the index of one past the end of the exmined block in win.
	 * - Curw is the index of one past the end of the exmined block in
	 *   curscr.
	 * - bsize is the current size of the examined block.
	*/
	for (bsize = bot - top; bsize >= THRESH; bsize--) {
		for (startw = top; startw <= bot - bsize; startw++)
			for (starts = top; starts <= bot - bsize;
			    starts++) {
				for (curw = startw, curs = starts;
				    curs < starts + bsize; curw++, curs++)
					if (win->lines[curw]->flags &
					    __FORCEPAINT ||
					    (win->lines[curw]->hash !=
						curscr->lines[curs]->hash ||
						memcmp(win->lines[curw]->line,
						    curscr->lines[curs]->line,
						    win->maxx * __LDATASIZE) != 0))
						break;
				if (curs == starts + bsize)
					goto done;
			}
	}
done:
	/* Did not find anything */
	if (bsize < THRESH)
		return;

#ifdef DEBUG
	__CTRACE("quickch:bsize=%d,starts=%d,startw=%d,curw=%d,curs=%d,top=%d,bot=%d\n",
	    bsize, starts, startw, curw, curs, top, bot);
#endif

	/*
	 * Make sure that there is no overlap between the bottom and top
	 * regions and the middle scrolled block.
	 */
	if (bot < curs)
		bot = curs - 1;
	if (top > starts)
		top = starts;

	n = startw - starts;

#ifdef DEBUG
	__CTRACE("#####################################\n");
	for (i = 0; i < curscr->maxy; i++) {
		__CTRACE("C: %d:", i);
		__CTRACE(" 0x%x \n", curscr->lines[i]->hash);
		for (j = 0; j < curscr->maxx; j++)
			__CTRACE("%c", curscr->lines[i]->line[j].ch);
		__CTRACE("\n");
		for (j = 0; j < curscr->maxx; j++)
			__CTRACE("%x", curscr->lines[i]->line[j].attr);
		__CTRACE("\n");
		__CTRACE("W: %d:", i);
		__CTRACE(" 0x%x \n", win->lines[i]->hash);
		__CTRACE(" 0x%x ", win->lines[i]->flags);
		for (j = 0; j < win->maxx; j++)
			__CTRACE("%c", win->lines[i]->line[j].ch);
		__CTRACE("\n");
		for (j = 0; j < win->maxx; j++)
			__CTRACE("%x", win->lines[i]->line[j].attr);
		__CTRACE("\n");
	}
#endif

	/* So we don't have to call __hash() each time */
	for (i = 0; i < win->maxx; i++) {
		buf[i].ch = ' ';
		buf[i].attr = 0;
	}
	blank_hash = __hash((char *) buf, (int) (win->maxx * __LDATASIZE));

	/*
	 * Perform the rotation to maintain the consistency of curscr.
	 * This is hairy since we are doing an *in place* rotation.
	 * Invariants of the loop:
	 * - I is the index of the current line.
	 * - Target is the index of the target of line i.
	 * - Tmp1 points to current line (i).
	 * - Tmp2 and points to target line (target);
	 * - Cur_period is the index of the end of the current period.
	 *   (see below).
	 *
	 * There are 2 major issues here that make this rotation non-trivial:
	 * 1.  Scrolling in a scrolling region bounded by the top
	 *     and bottom regions determined (whose size is sc_region).
	 * 2.  As a result of the use of the mod function, there may be a
	 *     period introduced, i.e., 2 maps to 4, 4 to 6, n-2 to 0, and
	 *     0 to 2, which then causes all odd lines not to be rotated.
	 *     To remedy this, an index of the end ( = beginning) of the
	 *     current 'period' is kept, cur_period, and when it is reached,
	 *     the next period is started from cur_period + 1 which is
	 *     guaranteed not to have been reached since that would mean that
	 *     all records would have been reached. (think about it...).
	 *
	 * Lines in the rotation can have 3 attributes which are marked on the
	 * line so that curscr is consistent with the visual screen.
	 * 1.  Not dirty -- lines inside the scrolled block, top region or
	 *                  bottom region.
	 * 2.  Blank lines -- lines in the differential of the scrolling
	 *		      region adjacent to top and bot regions
	 *                    depending on scrolling direction.
	 * 3.  Dirty line -- all other lines are marked dirty.
	 */
	sc_region = bot - top + 1;
	i = top;
	tmp1 = curscr->lines[top];
	cur_period = top;
	for (j = top; j <= bot; j++) {
		target = (i - top + n + sc_region) % sc_region + top;
		tmp2 = curscr->lines[target];
		curscr->lines[target] = tmp1;
		/* Mark block as clean and blank out scrolled lines. */
		clp = curscr->lines[target];
#ifdef DEBUG
		__CTRACE("quickch: n=%d startw=%d curw=%d i = %d target=%d ",
		    n, startw, curw, i, target);
#endif
		if ((target >= startw && target < curw) || target < top
		    || target > bot) {
#ifdef DEBUG
			__CTRACE("-- notdirty");
#endif
			win->lines[target]->flags &= ~__ISDIRTY;
		} else
			if ((n > 0 && target >= top && target < top + n) ||
			    (n < 0 && target <= bot && target > bot + n)) {
				if (clp->hash != blank_hash || memcmp(clp->line,
				    buf, win->maxx * __LDATASIZE) !=0) {
					(void)memcpy(clp->line,  buf,
					    win->maxx * __LDATASIZE);
#ifdef DEBUG
					__CTRACE("-- blanked out: dirty");
#endif
					clp->hash = blank_hash;
					__touchline(win, target, 0, (int) win->maxx - 1, 0);
				} else {
					__touchline(win, target, 0, (int) win->maxx - 1, 0);
#ifdef DEBUG
					__CTRACE(" -- blank line already: dirty");
#endif
				}
			} else {
#ifdef DEBUG
				__CTRACE(" -- dirty");
#endif
				__touchline(win, target, 0, (int) win->maxx - 1, 0);
			}
#ifdef DEBUG
		__CTRACE("\n");
#endif
		if (target == cur_period) {
			i = target + 1;
			tmp1 = curscr->lines[i];
			cur_period = i;
		} else {
			tmp1 = tmp2;
			i = target;
		}
	}
#ifdef DEBUG
	__CTRACE("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$\n");
	for (i = 0; i < curscr->maxy; i++) {
		__CTRACE("C: %d:", i);
		for (j = 0; j < curscr->maxx; j++)
			__CTRACE("%c", curscr->lines[i]->line[j].ch);
		__CTRACE("\n");
		__CTRACE("W: %d:", i);
		for (j = 0; j < win->maxx; j++)
			__CTRACE("%c", win->lines[i]->line[j].ch);
		__CTRACE("\n");
	}
#endif
	if (n != 0) {
		WINDOW *wp;
		scrolln(win, starts, startw, curs, bot, top);
		/*
		 * Need to repoint any subwindow lines to the rotated
		 * line structured.
		 */
		for (wp = win->nextp; wp != win; wp = wp->nextp)
			__set_subwin(win, wp);
	}
}

/*
 * scrolln --
 *	Scroll n lines, where n is starts - startw.
 */
static void /* ARGSUSED */
scrolln(win, starts, startw, curs, bot, top)
	WINDOW *win;
	int	starts, startw, curs, bot, top;
{
	int	i, oy, ox, n;

	oy = curscr->cury;
	ox = curscr->curx;
	n = starts - startw;

	/*
	 * XXX
	 * The initial tests that set __noqch don't let us reach here unless
	 * we have either CS + HO + SF/sf/SR/sr, or AL + DL.  SF/sf and SR/sr
	 * scrolling can only shift the entire scrolling region, not just a
	 * part of it, which means that the quickch() routine is going to be
	 * sadly disappointed in us if we don't have CS as well.
	 *
	 * If CS, HO and SF/sf are set, can use the scrolling region.  Because
	 * the cursor position after CS is undefined, we need HO which gives us
	 * the ability to move to somewhere without knowledge of the current
	 * location of the cursor.  Still call __mvcur() anyway, to update its
	 * idea of where the cursor is.
	 *
	 * When the scrolling region has been set, the cursor has to be at the
	 * last line of the region to make the scroll happen.
	 *
	 * Doing SF/SR or AL/DL appears faster on the screen than either sf/sr
	 * or al/dl, and, some terminals have AL/DL, sf/sr, and CS, but not
	 * SF/SR.  So, if we're scrolling almost all of the screen, try and use
	 * AL/DL, otherwise use the scrolling region.  The "almost all" is a
	 * shameless hack for vi.
	 */
	if (n > 0) {
		if (CS != NULL && HO != NULL && (SF != NULL ||
		    ((AL == NULL || DL == NULL ||
		    top > 3 || bot + 3 < win->maxy) && sf != NULL))) {
			tputs(__tscroll(CS, top, bot + 1), 0, __cputchar);
			__mvcur(oy, ox, 0, 0, 1);
			tputs(HO, 0, __cputchar);
			__mvcur(0, 0, bot, 0, 1);
			if (SF != NULL)
				tputs(__tscroll(SF, n, 0), 0, __cputchar);
			else
				for (i = 0; i < n; i++)
					tputs(sf, 0, __cputchar);
			tputs(__tscroll(CS, 0, (int) win->maxy), 0, __cputchar);
			__mvcur(bot, 0, 0, 0, 1);
			tputs(HO, 0, __cputchar);
			__mvcur(0, 0, oy, ox, 1);
			return;
		}

		/* Scroll up the block. */
		if (SF != NULL && top == 0) {
			__mvcur(oy, ox, bot, 0, 1);
			tputs(__tscroll(SF, n, 0), 0, __cputchar);
		} else
			if (DL != NULL) {
				__mvcur(oy, ox, top, 0, 1);
				tputs(__tscroll(DL, n, 0), 0, __cputchar);
			} else
				if (dl != NULL) {
					__mvcur(oy, ox, top, 0, 1);
					for (i = 0; i < n; i++)
						tputs(dl, 0, __cputchar);
				} else
					if (sf != NULL && top == 0) {
						__mvcur(oy, ox, bot, 0, 1);
						for (i = 0; i < n; i++)
							tputs(sf, 0, __cputchar);
					} else
						abort();

		/* Push down the bottom region. */
		__mvcur(top, 0, bot - n + 1, 0, 1);
		if (AL != NULL)
			tputs(__tscroll(AL, n, 0), 0, __cputchar);
		else
			if (al != NULL)
				for (i = 0; i < n; i++)
					tputs(al, 0, __cputchar);
			else
				abort();
		__mvcur(bot - n + 1, 0, oy, ox, 1);
	} else {
		/*
		 * !!!
		 * n < 0
		 *
		 * If CS, HO and SR/sr are set, can use the scrolling region.
		 * See the above comments for details.
		 */
		if (CS != NULL && HO != NULL && (SR != NULL ||
		    ((AL == NULL || DL == NULL ||
		    top > 3 || bot + 3 < win->maxy) && sr != NULL))) {
			tputs(__tscroll(CS, top, bot + 1), 0, __cputchar);
			__mvcur(oy, ox, 0, 0, 1);
			tputs(HO, 0, __cputchar);
			__mvcur(0, 0, top, 0, 1);

			if (SR != NULL)
				tputs(__tscroll(SR, -n, 0), 0, __cputchar);
			else
				for (i = n; i < 0; i++)
					tputs(sr, 0, __cputchar);
			tputs(__tscroll(CS, 0, (int) win->maxy), 0, __cputchar);
			__mvcur(top, 0, 0, 0, 1);
			tputs(HO, 0, __cputchar);
			__mvcur(0, 0, oy, ox, 1);
			return;
		}

		/* Preserve the bottom lines. */
		__mvcur(oy, ox, bot + n + 1, 0, 1);
		if (SR != NULL && bot == win->maxy)
			tputs(__tscroll(SR, -n, 0), 0, __cputchar);
		else
			if (DL != NULL)
				tputs(__tscroll(DL, -n, 0), 0, __cputchar);
			else
				if (dl != NULL)
					for (i = n; i < 0; i++)
						tputs(dl, 0, __cputchar);
				else
					if (sr != NULL && bot == win->maxy)
						for (i = n; i < 0; i++)
							tputs(sr, 0, __cputchar);
					else
						abort();

		/* Scroll the block down. */
		__mvcur(bot + n + 1, 0, top, 0, 1);
		if (AL != NULL)
			tputs(__tscroll(AL, -n, 0), 0, __cputchar);
		else
			if (al != NULL)
				for (i = n; i < 0; i++)
					tputs(al, 0, __cputchar);
			else
				abort();
		__mvcur(top, 0, oy, ox, 1);
	}
}