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refresh.c revision 1.119
      1 /*	$NetBSD: refresh.c,v 1.119 2022/04/12 07:03:04 blymn Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1981, 1993, 1994
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 #if 0
     35 static char sccsid[] = "@(#)refresh.c	8.7 (Berkeley) 8/13/94";
     36 #else
     37 __RCSID("$NetBSD: refresh.c,v 1.119 2022/04/12 07:03:04 blymn Exp $");
     38 #endif
     39 #endif				/* not lint */
     40 
     41 #include <poll.h>
     42 #include <stdlib.h>
     43 #include <string.h>
     44 #include <assert.h>
     45 
     46 #include "curses.h"
     47 #include "curses_private.h"
     48 
     49 static void	domvcur(WINDOW *, int, int, int, int);
     50 static void	putattr(__LDATA *);
     51 static void	putattr_out(__LDATA *);
     52 static int	putch(__LDATA *, __LDATA *, int, int);
     53 static int	putchbr(__LDATA *, __LDATA *, __LDATA *, int, int);
     54 static int	makech(int);
     55 static void	quickch(void);
     56 static void	scrolln(int, int, int, int, int);
     57 
     58 static int	_wnoutrefresh(WINDOW *, int, int, int, int, int, int);
     59 
     60 static int celleq(__LDATA *, __LDATA *);
     61 static int lineeq(__LDATA *, __LDATA *, size_t);
     62 
     63 #define	CHECK_INTERVAL		5 /* Change N lines before checking typeahead */
     64 
     65 #ifndef _CURSES_USE_MACROS
     66 
     67 /*
     68  * refresh --
     69  *	Make the current screen look like "stdscr" over the area covered by
     70  *	stdscr.
     71  */
     72 int
     73 refresh(void)
     74 {
     75 
     76 	return wrefresh(stdscr);
     77 }
     78 
     79 #endif
     80 
     81 /*
     82  * wnoutrefresh --
     83  *	Add the contents of "win" to the virtual window.
     84  */
     85 int
     86 wnoutrefresh(WINDOW *win)
     87 {
     88 
     89 	__CTRACE(__CTRACE_REFRESH,
     90 	    "wnoutrefresh: win %p, begy %d, begx %d, maxy %d, maxx %d\n",
     91 	    win, win->begy, win->begx, win->maxy, win->maxx);
     92 
     93 	return _wnoutrefresh(win, 0, 0, win->begy, win->begx,
     94 	    win->maxy, win->maxx);
     95 }
     96 
     97 /*
     98  * pnoutrefresh --
     99  *	Add the contents of "pad" to the virtual window.
    100  */
    101 int
    102 pnoutrefresh(WINDOW *pad, int pbegy, int pbegx, int sbegy, int sbegx,
    103 	     int smaxy, int smaxx)
    104 {
    105 	int pmaxy, pmaxx;
    106 
    107 	__CTRACE(__CTRACE_REFRESH, "pnoutrefresh: pad %p, flags 0x%08x\n",
    108 	    pad, pad->flags);
    109 	__CTRACE(__CTRACE_REFRESH,
    110 	    "pnoutrefresh: (%d, %d), (%d, %d), (%d, %d)\n",
    111 	    pbegy, pbegx, sbegy, sbegx, smaxy, smaxx);
    112 
    113 	/* SUS says if these are negative, they should be treated as zero */
    114 	if (pbegy < 0)
    115 		pbegy = 0;
    116 	if (pbegx < 0)
    117 		pbegx = 0;
    118 	if (sbegy < 0)
    119 		sbegy = 0;
    120 	if (sbegx < 0)
    121 		sbegx = 0;
    122 
    123 	/* Calculate rectangle on pad - used by _wnoutrefresh */
    124 	pmaxy = pbegy + smaxy - sbegy + 1;
    125 	pmaxx = pbegx + smaxx - sbegx + 1;
    126 
    127 	/* Check rectangle fits in pad */
    128 	if (pmaxy > pad->maxy - pad->begy)
    129 		pmaxy = pad->maxy - pad->begy;
    130 	if (pmaxx > pad->maxx - pad->begx)
    131 		pmaxx = pad->maxx - pad->begx;
    132 
    133 	if (smaxy - sbegy < 0 || smaxx - sbegx < 0 )
    134 		return ERR;
    135 
    136 	return _wnoutrefresh(pad,
    137 	    pad->begy + pbegy, pad->begx + pbegx, pad->begy + sbegy,
    138 	    pad->begx + sbegx, pmaxy, pmaxx);
    139 }
    140 
    141 /*
    142  * _wnoutrefresh --
    143  *	Does the grunt work for wnoutrefresh to the given screen.
    144  *	Copies the part of the window given by the rectangle
    145  *	(begy, begx) to (maxy, maxx) at screen position (wbegy, wbegx).
    146  */
    147 static int
    148 _wnoutrefresh(WINDOW *win, int begy, int begx, int wbegy, int wbegx,
    149               int maxy, int maxx)
    150 {
    151 	SCREEN *screen = win->screen;
    152 	short	sy, wy, wx, y_off, x_off, mx, dy_off, dx_off, endy;
    153 	int newy, newx;
    154 	__LINE	*wlp, *vlp, *dwlp;
    155 	WINDOW	*sub_win, *orig, *swin, *dwin;
    156 
    157 	__CTRACE(__CTRACE_REFRESH, "_wnoutrefresh: win %p, flags 0x%08x\n",
    158 	    win, win->flags);
    159 	__CTRACE(__CTRACE_REFRESH,
    160 	    "_wnoutrefresh: (%d, %d), (%d, %d), (%d, %d)\n",
    161 	    begy, begx, wbegy, wbegx, maxy, maxx);
    162 
    163 	if (screen->curwin)
    164 		return OK;
    165 
    166 	swin = dwin = win;
    167 	if (win->flags & __ISDERWIN)
    168 		swin = win->orig;
    169 
    170 	/*
    171 	 * Recurse through any sub-windows, mark as dirty lines on the parent
    172 	 * window that are dirty on the sub-window and clear the dirty flag on
    173 	 * the sub-window.
    174 	 */
    175 	if (dwin->orig == 0) {
    176 		orig = dwin;
    177 		for (sub_win = dwin->nextp; sub_win != orig;
    178 		    sub_win = sub_win->nextp) {
    179 			if (sub_win->flags & __ISDERWIN)
    180 				continue;
    181 			__CTRACE(__CTRACE_REFRESH,
    182 			    "wnout_refresh: win %p, sub_win %p\n",
    183 			    orig, sub_win);
    184 			for (sy = 0; sy < sub_win->maxy; sy++) {
    185 				if (sub_win->alines[sy]->flags & __ISDIRTY) {
    186 					orig->alines[sy + sub_win->begy - orig->begy]->flags
    187 					    |= __ISDIRTY;
    188 					sub_win->alines[sy]->flags
    189 					    &= ~__ISDIRTY;
    190 				}
    191 				if (sub_win->alines[sy]->flags & __ISFORCED) {
    192 					orig->alines[sy + sub_win->begy - orig->begy]->flags
    193 					    |= __ISFORCED;
    194 					sub_win->alines[sy]->flags
    195 					    &= ~__ISFORCED;
    196 				}
    197 			}
    198 		}
    199 	}
    200 
    201 	/* Check that cursor position on "win" is valid for "__virtscr" */
    202 	newy = wbegy + dwin->cury - begy;
    203 	newx = wbegx + dwin->curx - begx;
    204 	if (begy <= dwin->cury && dwin->cury < maxy
    205 	    && 0 <= newy && newy < screen->__virtscr->maxy)
    206 		screen->__virtscr->cury = newy;
    207 	if (begx <= dwin->curx && dwin->curx < maxx
    208 	    && 0 <= newx && newx < screen->__virtscr->maxx)
    209 		screen->__virtscr->curx = newx;
    210 
    211 	/* Copy the window flags from "win" to "__virtscr" */
    212 	if (dwin->flags & __CLEAROK) {
    213 		if (dwin->flags & __FULLWIN)
    214 			screen->__virtscr->flags |= __CLEAROK;
    215 		dwin->flags &= ~__CLEAROK;
    216 	}
    217 	screen->__virtscr->flags &= ~__LEAVEOK;
    218 	screen->__virtscr->flags |= dwin->flags;
    219 
    220 	if ((dwin->flags & __ISDERWIN) != 0)
    221 		endy = begy + maxy;
    222 	else
    223 		endy = maxy;
    224 
    225 	for (wy = begy, y_off = wbegy, dy_off = 0; wy < endy &&
    226 	    y_off < screen->__virtscr->maxy; wy++, y_off++, dy_off++)
    227 	{
    228 		wlp = swin->alines[wy];
    229 		dwlp = dwin->alines[dy_off];
    230 #ifdef DEBUG
    231 		__CTRACE(__CTRACE_REFRESH,
    232 		    "_wnoutrefresh: wy %d\tf %d\tl %d\tflags %x\n",
    233 		    wy, *wlp->firstchp, *wlp->lastchp, wlp->flags);
    234 
    235 		char *_wintype;
    236 
    237 		if ((dwin->flags & __ISDERWIN) != 0)
    238 			_wintype = "derwin";
    239 		else
    240 			_wintype = "dwin";
    241 
    242 		__CTRACE(__CTRACE_REFRESH,
    243 		    "_wnoutrefresh: %s wy %d\tf %d\tl %d\tflags %x\n",
    244 		    _wintype, dy_off, *dwlp->firstchp, *dwlp->lastchp,
    245 		    dwlp->flags);
    246 		__CTRACE(__CTRACE_REFRESH,
    247 		    "_wnoutrefresh: %s maxx %d\tch_off %d wlp %p\n",
    248 		    _wintype, dwin->maxx, dwin->ch_off, wlp);
    249 #endif
    250 		if (((wlp->flags & (__ISDIRTY | __ISFORCED)) == 0) &&
    251 		    ((dwlp->flags & (__ISDIRTY | __ISFORCED)) == 0))
    252 			continue;
    253 		__CTRACE(__CTRACE_REFRESH,
    254 		    "_wnoutrefresh: line y_off %d (dy_off %d) is dirty\n",
    255 		    y_off, dy_off);
    256 
    257 		wlp = swin->alines[wy];
    258 		vlp = screen->__virtscr->alines[y_off];
    259 
    260 		if ((*wlp->firstchp < maxx + swin->ch_off &&
    261 		    *wlp->lastchp >= swin->ch_off) ||
    262 		    ((((dwin->flags & __ISDERWIN) != 0) &&
    263 		     (*dwlp->firstchp < dwin->maxx + dwin->ch_off &&
    264 		      *dwlp->lastchp >= dwin->ch_off))))
    265 		{
    266 			/* Set start column */
    267 			wx = begx;
    268 			x_off = wbegx;
    269 			dx_off = 0;
    270 			/*
    271 			 * if a derwin then source change pointers aren't
    272 			 * relevant.
    273 			 */
    274 			if ((dwin->flags & __ISDERWIN) != 0)
    275 				mx = wx + maxx;
    276 			else {
    277 				if (*wlp->firstchp - swin->ch_off > 0) {
    278 					wx += *wlp->firstchp - swin->ch_off;
    279 					x_off += *wlp->firstchp - swin->ch_off;
    280 				}
    281 				mx = maxx;
    282 				if (mx > *wlp->lastchp - swin->ch_off + 1)
    283 					mx = *dwlp->lastchp - dwin->ch_off + 1;
    284 				if (x_off + (mx - wx) > screen->__virtscr->maxx)
    285 					mx -= (x_off + maxx) -
    286 					    screen->__virtscr->maxx;
    287 			}
    288 
    289 			/* Copy line from "win" to "__virtscr". */
    290 			while (wx < mx) {
    291 				__CTRACE(__CTRACE_REFRESH,
    292 				    "_wnoutrefresh: copy from %d, "
    293 				    "%d to %d, %d: '%s', 0x%x",
    294 				    wy, wx, y_off, x_off,
    295 				    unctrl(wlp->line[wx].ch),
    296 				    wlp->line[wx].attr);
    297 				__CTRACE(__CTRACE_REFRESH,
    298 				    " (curdest %s, 0x%x)",
    299 				    unctrl(vlp->line[x_off].ch),
    300 				    vlp->line[x_off].attr);
    301 				/* Copy character */
    302 				vlp->line[x_off].ch = wlp->line[wx].ch;
    303 				/* Copy attributes  */
    304 				vlp->line[x_off].attr = wlp->line[wx].attr;
    305 #ifdef HAVE_WCHAR
    306 				vlp->line[x_off].wcols = wlp->line[wx].wcols;
    307 #endif /* HAVE_WCHAR */
    308 				if (win->flags & __ISDERWIN) {
    309 					dwlp->line[dx_off].ch =
    310 						wlp->line[wx].ch;
    311 					dwlp->line[dx_off].attr =
    312 						wlp->line[wx].attr;
    313 #ifdef HAVE_WCHAR
    314 					dwlp->line[dx_off].wcols =
    315 						wlp->line[wx].wcols;
    316 #endif /* HAVE_WCHAR */
    317 				}
    318 
    319 #ifdef HAVE_WCHAR
    320 				if (wlp->line[wx].ch == win->bch) {
    321 					vlp->line[x_off].ch = win->bch;
    322 					vlp->line[x_off].wcols = win->wcols;
    323 					if (_cursesi_copy_nsp(win->bnsp,
    324 							      &vlp->line[x_off])
    325 					    == ERR)
    326 						return ERR;
    327 					if (win->flags & __ISDERWIN) {
    328 						dwlp->line[dx_off].ch =
    329 							win->bch;
    330 						dwlp->line[dx_off].wcols =
    331 						    win->wcols;
    332 						if (_cursesi_copy_nsp(win->bnsp,
    333 						     &dwlp->line[dx_off])
    334 						    == ERR)
    335 							return ERR;
    336 					}
    337 				}
    338 #endif /* HAVE_WCHAR */
    339 				__CTRACE(__CTRACE_REFRESH, " = '%s', 0x%x\n",
    340 				    unctrl(vlp->line[x_off].ch),
    341 				    vlp->line[x_off].attr);
    342 				wx++; /* XXX should be + wcols, need to properly set continuation flag on multi-col */
    343 				x_off++;
    344 				dx_off++;
    345 			}
    346 
    347 			/* Set flags on "__virtscr" and unset on "win". */
    348 			if (wlp->flags & __ISPASTEOL)
    349 				vlp->flags |= __ISPASTEOL;
    350 			else
    351 				vlp->flags &= ~__ISPASTEOL;
    352 			if (wlp->flags & __ISDIRTY)
    353 				vlp->flags |= __ISDIRTY;
    354 			if (wlp->flags & __ISFORCED)
    355 				vlp->flags |= __ISFORCED;
    356 
    357 #ifdef DEBUG
    358 			__CTRACE(__CTRACE_REFRESH,
    359 			    "win: firstch = %d, lastch = %d\n",
    360 			    *wlp->firstchp, *wlp->lastchp);
    361 			if (win->flags & __ISDERWIN) {
    362 				__CTRACE(__CTRACE_REFRESH,
    363 				    "derwin: fistch = %d, lastch = %d\n",
    364 				    *dwlp->firstchp, *dwlp->lastchp);
    365 			}
    366 #endif
    367 			/* Set change pointers on "__virtscr". */
    368 			if (*vlp->firstchp >
    369 				*wlp->firstchp + wbegx - win->ch_off)
    370 					*vlp->firstchp =
    371 					    *wlp->firstchp + wbegx - win->ch_off;
    372 			if (*vlp->lastchp <
    373 				*wlp->lastchp + wbegx - win->ch_off)
    374 					*vlp->lastchp =
    375 					    *wlp->lastchp + wbegx - win->ch_off;
    376 
    377 			if (win->flags & __ISDERWIN) {
    378 				if (*vlp->firstchp >
    379 				    *dwlp->firstchp + wbegx - dwin->ch_off)
    380 				{
    381 					*vlp->firstchp =
    382 					    *dwlp->firstchp + wbegx
    383 						- dwin->ch_off;
    384 					vlp->flags |= __ISDIRTY;
    385 				}
    386 
    387 				if (*vlp->lastchp <
    388 				    *dwlp->lastchp + wbegx - dwin->ch_off)
    389 				{
    390 					*vlp->lastchp = *dwlp->lastchp
    391 					    + wbegx - dwin->ch_off;
    392 					vlp->flags |= __ISDIRTY;
    393 				}
    394 			}
    395 
    396 			__CTRACE(__CTRACE_REFRESH,
    397 			    "__virtscr: firstch = %d, lastch = %d\n",
    398 			    *vlp->firstchp, *vlp->lastchp);
    399 			/*
    400 			 * Unset change pointers only if a window and we
    401 			 * are not forcing a redraw. A pad can be displayed
    402 			 * again without any of the contents changing.
    403 			 */
    404 			if ((!(win->flags & __ISPAD)) ||
    405 			    ((wlp->flags & __ISFORCED) == __ISFORCED))
    406 			{
    407 				/* Set change pointers on "win". */
    408 				if (*wlp->firstchp >= win->ch_off)
    409 					*wlp->firstchp = maxx + win->ch_off;
    410 				if (*wlp->lastchp < maxx + win->ch_off)
    411 					*wlp->lastchp = win->ch_off;
    412 				if ((*wlp->lastchp < *wlp->firstchp) ||
    413 				    (*wlp->firstchp >= maxx + win->ch_off) ||
    414 				    (*wlp->lastchp <= win->ch_off)) {
    415 					__CTRACE(__CTRACE_REFRESH,
    416 					    "_wnoutrefresh: "
    417 					    "line %d notdirty\n", wy);
    418 					wlp->flags &= ~(__ISDIRTY | __ISFORCED);
    419 				}
    420 			}
    421 		}
    422 	}
    423 	return OK;
    424 }
    425 
    426 /*
    427  * wrefresh --
    428  *	Make the current screen look like "win" over the area covered by
    429  *	win.
    430  */
    431 int
    432 wrefresh(WINDOW *win)
    433 {
    434 	int retval;
    435 	int pbegx, pbegy;
    436 
    437 	__CTRACE(__CTRACE_REFRESH, "wrefresh: win %p\n", win);
    438 
    439 	_cursesi_screen->curwin = (win == _cursesi_screen->curscr);
    440 	if (!_cursesi_screen->curwin) {
    441 		pbegx = pbegy = 0;
    442 		if ((win->flags & __ISDERWIN) == __ISDERWIN) {
    443 			pbegx = win->derx;
    444 			pbegy = win->dery;
    445 	__CTRACE(__CTRACE_REFRESH, "wrefresh: derwin, begy = %d, begx = %x\n",
    446 		pbegy, pbegx);
    447 		}
    448 		retval = _wnoutrefresh(win, pbegy, pbegx, win->begy, win->begx,
    449 		    win->maxy, win->maxx);
    450 	} else
    451 		retval = OK;
    452 	if (retval == OK) {
    453 		retval = doupdate();
    454 		if (!(win->flags & __LEAVEOK)) {
    455 			win->cury = max(0, curscr->cury - win->begy);
    456 			win->curx = max(0, curscr->curx - win->begx);
    457 		}
    458 	}
    459 	_cursesi_screen->curwin = 0;
    460 	return retval;
    461 }
    462 
    463  /*
    464  * prefresh --
    465  *	Make the current screen look like "pad" over the area coverd by
    466  *	the specified area of pad.
    467  */
    468 int
    469 prefresh(WINDOW *pad, int pbegy, int pbegx, int sbegy, int sbegx,
    470 	int smaxy, int smaxx)
    471 {
    472 	int retval;
    473 
    474 	__CTRACE(__CTRACE_REFRESH, "prefresh: pad %p, flags 0x%08x\n",
    475 	    pad, pad->flags);
    476 	/* Retain values in case pechochar() is called. */
    477 	pad->pbegy = pbegy;
    478 	pad->pbegx = pbegx;
    479 	pad->sbegy = sbegy;
    480 	pad->sbegx = sbegx;
    481 	pad->smaxy = smaxy;
    482 	pad->smaxx = smaxx;
    483 
    484 	/* Use pnoutrefresh() to avoid duplicating code here */
    485 	retval = pnoutrefresh(pad, pbegy, pbegx, sbegy, sbegx, smaxy, smaxx);
    486 	if (retval == OK) {
    487 		retval = doupdate();
    488 		if (!(pad->flags & __LEAVEOK)) {
    489 			pad->cury = max(0, pbegy + (curscr->cury - sbegy));
    490 			pad->curx = max(0, pbegx + (curscr->curx - sbegx));
    491 		}
    492 	}
    493 	return retval;
    494 }
    495 
    496 /*
    497  * doupdate --
    498  *	Make the current screen look like the virtual window "__virtscr".
    499  */
    500 int
    501 doupdate(void)
    502 {
    503 	WINDOW	*win;
    504 	__LINE	*wlp, *vlp;
    505 	short	 wy;
    506 	int	 dnum, was_cleared, changed;
    507 
    508 	/* Check if we need to restart ... */
    509 	if (_cursesi_screen->endwin)
    510 		__restartwin();
    511 
    512 	if (_cursesi_screen->curwin)
    513 		win = curscr;
    514 	else
    515 		win = _cursesi_screen->__virtscr;
    516 
    517 	/* Initialize loop parameters. */
    518 	_cursesi_screen->ly = curscr->cury;
    519 	_cursesi_screen->lx = curscr->curx;
    520 	wy = 0;
    521 
    522 	if (!_cursesi_screen->curwin) {
    523 		for (wy = 0; wy < win->maxy; wy++) {
    524 			wlp = win->alines[wy];
    525 			if (wlp->flags & __ISDIRTY)
    526 				wlp->hash = __hash_line(wlp->line, win->maxx);
    527 		}
    528 	}
    529 
    530 	was_cleared = 0;
    531 	if ((win->flags & __CLEAROK) || (curscr->flags & __CLEAROK) ||
    532 	    _cursesi_screen->curwin)
    533 	{
    534 		if (curscr->wattr & __COLOR)
    535 			__unsetattr(0);
    536 		tputs(clear_screen, 0, __cputchar);
    537 		_cursesi_screen->ly = 0;
    538 		_cursesi_screen->lx = 0;
    539 		if (!_cursesi_screen->curwin) {
    540 			curscr->flags &= ~__CLEAROK;
    541 			curscr->cury = 0;
    542 			curscr->curx = 0;
    543 			werase(curscr);
    544 		}
    545 		__touchwin(win, 0);
    546 		win->flags &= ~__CLEAROK;
    547 		/* note we cleared for later */
    548 		was_cleared = 1;
    549 	}
    550 	if (!cursor_address) {
    551 		if (win->curx != 0)
    552 			__cputchar('\n');
    553 		if (!_cursesi_screen->curwin)
    554 			werase(curscr);
    555 	}
    556 	__CTRACE(__CTRACE_REFRESH, "doupdate: (%p): curwin = %d\n", win,
    557 	    _cursesi_screen->curwin);
    558 	__CTRACE(__CTRACE_REFRESH, "doupdate: \tfirstch\tlastch\n");
    559 
    560 	if (!_cursesi_screen->curwin) {
    561 		/*
    562 		 * Invoke quickch() only if more than a quarter of the lines
    563 		 * in the window are dirty.
    564 		 */
    565 		for (wy = 0, dnum = 0; wy < win->maxy; wy++)
    566 			if (win->alines[wy]->flags & __ISDIRTY)
    567 				dnum++;
    568 		if (!__noqch && dnum > (int) win->maxy / 4)
    569 			quickch();
    570 	}
    571 
    572 #ifdef DEBUG
    573 	{
    574 		int	i, j;
    575 
    576 		__CTRACE(__CTRACE_REFRESH,
    577 		    "#####################################\n");
    578 		__CTRACE(__CTRACE_REFRESH,
    579 		    "stdscr(%p)-curscr(%p)-__virtscr(%p)\n",
    580 		    stdscr, curscr, _cursesi_screen->__virtscr);
    581 		for (i = 0; i < curscr->maxy; i++) {
    582 			__CTRACE(__CTRACE_REFRESH, "C: %d:", i);
    583 			__CTRACE(__CTRACE_REFRESH, " 0x%x \n",
    584 			    curscr->alines[i]->hash);
    585 			for (j = 0; j < curscr->maxx; j++)
    586 				__CTRACE(__CTRACE_REFRESH, "%c",
    587 				    curscr->alines[i]->line[j].ch);
    588 			__CTRACE(__CTRACE_REFRESH, "\n");
    589 			__CTRACE(__CTRACE_REFRESH, " attr:");
    590 			for (j = 0; j < curscr->maxx; j++)
    591 				__CTRACE(__CTRACE_REFRESH, " %x",
    592 				    curscr->alines[i]->line[j].attr);
    593 			__CTRACE(__CTRACE_REFRESH, "\n");
    594 #ifdef HAVE_WCHAR
    595 			__CTRACE(__CTRACE_REFRESH, " wcols:");
    596 			for (j = 0; j < curscr->maxx; j++)
    597 				__CTRACE(__CTRACE_REFRESH, " %d",
    598 				    curscr->alines[i]->line[j].wcols);
    599 			__CTRACE(__CTRACE_REFRESH, "\n");
    600 #endif /* HAVE_WCHAR */
    601 			__CTRACE(__CTRACE_REFRESH, "W: %d:", i);
    602 			__CTRACE(__CTRACE_REFRESH, " 0x%x \n",
    603 			    win->alines[i]->hash);
    604 			__CTRACE(__CTRACE_REFRESH, " 0x%x ",
    605 			    win->alines[i]->flags);
    606 			for (j = 0; j < win->maxx; j++)
    607 				__CTRACE(__CTRACE_REFRESH, "%c",
    608 				    win->alines[i]->line[j].ch);
    609 			__CTRACE(__CTRACE_REFRESH, "\n");
    610 			__CTRACE(__CTRACE_REFRESH, " attr:");
    611 			for (j = 0; j < win->maxx; j++)
    612 				__CTRACE(__CTRACE_REFRESH, " %x",
    613 				    win->alines[i]->line[j].attr);
    614 			__CTRACE(__CTRACE_REFRESH, "\n");
    615 #ifdef HAVE_WCHAR
    616 			__CTRACE(__CTRACE_REFRESH, " wcols:");
    617 			for (j = 0; j < win->maxx; j++)
    618 				__CTRACE(__CTRACE_REFRESH, " %d",
    619 				    win->alines[i]->line[j].wcols);
    620 			__CTRACE(__CTRACE_REFRESH, "\n");
    621 			__CTRACE(__CTRACE_REFRESH, " nsp:");
    622 			for (j = 0; j < curscr->maxx; j++)
    623 				__CTRACE(__CTRACE_REFRESH, " %p",
    624 				    win->alines[i]->line[j].nsp);
    625 			__CTRACE(__CTRACE_REFRESH, "\n");
    626 			__CTRACE(__CTRACE_REFRESH, " bnsp:");
    627 			for (j = 0; j < curscr->maxx; j++)
    628 				__CTRACE(__CTRACE_REFRESH, " %p",
    629 				    win->bnsp);
    630 			__CTRACE(__CTRACE_REFRESH, "\n");
    631 #endif /* HAVE_WCHAR */
    632 		}
    633 	}
    634 #endif /* DEBUG */
    635 
    636 	changed = 0;
    637 	for (wy = 0; wy < win->maxy; wy++) {
    638 		wlp = win->alines[wy];
    639 		vlp = _cursesi_screen->__virtscr->alines[win->begy + wy];
    640 /* XXX: remove this */
    641 		__CTRACE(__CTRACE_REFRESH,
    642 		    "doupdate: wy %d\tf: %d\tl:%d\tflags %x\n",
    643 		    wy, *wlp->firstchp, *wlp->lastchp, wlp->flags);
    644 		if (!_cursesi_screen->curwin)
    645 			curscr->alines[wy]->hash = wlp->hash;
    646 		if (wlp->flags & __ISDIRTY || wlp->flags & __ISFORCED) {
    647 			__CTRACE(__CTRACE_REFRESH,
    648 			    "doupdate: [ISDIRTY]wy:%d\tf:%d\tl:%d\n", wy,
    649 			    *wlp->firstchp, *wlp->lastchp);
    650 			/*
    651 			 * We have just cleared so don't force an update
    652 			 * otherwise we spray neeedless blanks to a cleared
    653 			 * screen.  That is, unless, we are using color,
    654 			 * in this case we need to force the background
    655 			 * color to default.
    656 			 */
    657 			if ((was_cleared == 1) && (__using_color == 0))
    658 				win->alines[wy]->flags &= ~__ISFORCED;
    659 
    660 			if (makech(wy) == ERR)
    661 				return ERR;
    662 			else {
    663 				if (*wlp->firstchp >= 0)
    664 					*wlp->firstchp = win->maxx;
    665 				if (*wlp->lastchp < win->maxx)
    666 					*wlp->lastchp = win->ch_off;
    667 				if (*wlp->lastchp < *wlp->firstchp) {
    668 					__CTRACE(__CTRACE_REFRESH,
    669 					    "doupdate: line %d notdirty\n", wy);
    670 					wlp->flags &= ~(__ISDIRTY | __ISFORCED);
    671 				}
    672 
    673 				/* Check if we have input after
    674 				 * changing N lines. */
    675 				if (_cursesi_screen->checkfd != -1 &&
    676 				    ++changed == CHECK_INTERVAL)
    677 				{
    678 					struct pollfd fds[1];
    679 
    680 					/* If we have input, abort. */
    681 					fds[0].fd = _cursesi_screen->checkfd;
    682 					fds[0].events = POLLIN;
    683 					if (poll(fds, 1, 0) > 0)
    684 						goto cleanup;
    685 					changed = 0;
    686 				}
    687 			}
    688 		}
    689 
    690 		/*
    691 		 * virtscr is now synced for the line, unset the change
    692 		 * pointers.
    693 		 */
    694 		if (*vlp->firstchp >= 0)
    695 			*vlp->firstchp = _cursesi_screen->__virtscr->maxx;
    696 		if (*vlp->lastchp <= _cursesi_screen->__virtscr->maxx)
    697 			*vlp->lastchp = 0;
    698 
    699 		__CTRACE(__CTRACE_REFRESH, "\t%d\t%d\n",
    700 		    *wlp->firstchp, *wlp->lastchp);
    701 	}
    702 
    703 	__CTRACE(__CTRACE_REFRESH, "doupdate: ly=%d, lx=%d\n",
    704 	    _cursesi_screen->ly, _cursesi_screen->lx);
    705 
    706 	if (_cursesi_screen->curwin)
    707 		domvcur(win, _cursesi_screen->ly, _cursesi_screen->lx,
    708 			win->cury, win->curx);
    709 	else {
    710 		if (win->flags & __LEAVEOK) {
    711 			curscr->cury = _cursesi_screen->ly;
    712 			curscr->curx = _cursesi_screen->lx;
    713 		} else {
    714 			domvcur(win, _cursesi_screen->ly, _cursesi_screen->lx,
    715 				win->cury, win->curx);
    716 			curscr->cury = win->cury;
    717 			curscr->curx = win->curx;
    718 		}
    719 	}
    720 
    721 cleanup:
    722 	/* Don't leave the screen with attributes set. */
    723 	__unsetattr(0);
    724 	__do_color_init = 0;
    725 #ifdef DEBUG
    726 #ifdef HAVE_WCHAR
    727 	{
    728 		int	i, j;
    729 
    730 		__CTRACE(__CTRACE_REFRESH,
    731 		    "***********after*****************\n");
    732 		__CTRACE(__CTRACE_REFRESH,
    733 		    "stdscr(%p)-curscr(%p)-__virtscr(%p)\n",
    734 		    stdscr, curscr, _cursesi_screen->__virtscr);
    735 		for (i = 0; i < curscr->maxy; i++) {
    736 			for (j = 0; j < curscr->maxx; j++)
    737 				__CTRACE(__CTRACE_REFRESH,
    738 				    "[%d,%d](%x,%x,%d,%p)-(%x,%x,%d,%p)\n",
    739 				    i, j,
    740 				    curscr->alines[i]->line[j].ch,
    741 				    curscr->alines[i]->line[j].attr,
    742 				    curscr->alines[i]->line[j].wcols,
    743 				    curscr->alines[i]->line[j].nsp,
    744 				    _cursesi_screen->__virtscr->alines[i]->line[j].ch,
    745 				    _cursesi_screen->__virtscr->alines[i]->line[j].attr,
    746 				    _cursesi_screen->__virtscr->alines[i]->line[j].wcols,
    747 				    _cursesi_screen->__virtscr->alines[i]->line[j].nsp);
    748 		}
    749 	}
    750 #endif /* HAVE_WCHAR */
    751 #endif /* DEBUG */
    752 	return fflush(_cursesi_screen->outfd) == EOF ? ERR : OK;
    753 }
    754 
    755 static void
    756 putattr(__LDATA *nsp)
    757 {
    758 	attr_t	off, on;
    759 
    760 	__CTRACE(__CTRACE_REFRESH,
    761 	    "putattr: have attr %08x, need attr %08x\n",
    762 	    curscr->wattr
    763 #ifndef HAVE_WCHAR
    764 	    & __ATTRIBUTES
    765 #else
    766 	    & WA_ATTRIBUTES
    767 #endif
    768 	    ,  nsp->attr
    769 #ifndef HAVE_WCHAR
    770 	    & __ATTRIBUTES
    771 #else
    772 	    & WA_ATTRIBUTES
    773 #endif
    774 	    );
    775 
    776 	off = (~nsp->attr & curscr->wattr)
    777 #ifndef HAVE_WCHAR
    778 	    & __ATTRIBUTES
    779 #else
    780 	    & WA_ATTRIBUTES
    781 #endif
    782 	    ;
    783 
    784 	/*
    785 	 * Unset attributes as appropriate.  Unset first
    786 	 * so that the relevant attributes can be reset
    787 	 * (because 'me' unsets 'mb', 'md', 'mh', 'mk',
    788 	 * 'mp' and 'mr').  Check to see if we also turn off
    789 	 * standout, attributes and colour.
    790 	 */
    791 	if (off & __TERMATTR && exit_attribute_mode != NULL) {
    792 		tputs(exit_attribute_mode, 0, __cputchar);
    793 		curscr->wattr &= __mask_me;
    794 		off &= __mask_me;
    795 	}
    796 
    797 	/*
    798 	 * Exit underscore mode if appropriate.
    799 	 * Check to see if we also turn off standout,
    800 	 * attributes and colour.
    801 	 */
    802 	if (off & __UNDERSCORE && exit_underline_mode != NULL) {
    803 		tputs(exit_underline_mode, 0, __cputchar);
    804 		curscr->wattr &= __mask_ue;
    805 		off &= __mask_ue;
    806 	}
    807 
    808 	/*
    809 	 * Exit standout mode as appropriate.
    810 	 * Check to see if we also turn off underscore,
    811 	 * attributes and colour.
    812 	 * XXX
    813 	 * Should use uc if so/se not available.
    814 	 */
    815 	if (off & __STANDOUT && exit_standout_mode != NULL) {
    816 		tputs(exit_standout_mode, 0, __cputchar);
    817 		curscr->wattr &= __mask_se;
    818 		off &= __mask_se;
    819 	}
    820 
    821 	if (off & __ALTCHARSET && exit_alt_charset_mode != NULL) {
    822 		tputs(exit_alt_charset_mode, 0, __cputchar);
    823 		curscr->wattr &= ~__ALTCHARSET;
    824 	}
    825 
    826 	/* Set/change colour as appropriate. */
    827 	if (__using_color)
    828 		__set_color(curscr, nsp->attr & __COLOR);
    829 
    830 	on = (nsp->attr & ~curscr->wattr)
    831 #ifndef HAVE_WCHAR
    832 	    & __ATTRIBUTES
    833 #else
    834 	    & WA_ATTRIBUTES
    835 #endif
    836 	    ;
    837 
    838 	/*
    839 	 * Enter standout mode if appropriate.
    840 	 */
    841 	if (on & __STANDOUT &&
    842 	    enter_standout_mode != NULL &&
    843 	    exit_standout_mode != NULL)
    844 	{
    845 		tputs(enter_standout_mode, 0, __cputchar);
    846 		curscr->wattr |= __STANDOUT;
    847 	}
    848 
    849 	/*
    850 	 * Enter underscore mode if appropriate.
    851 	 * XXX
    852 	 * Should use uc if us/ue not available.
    853 	 */
    854 	if (on & __UNDERSCORE &&
    855 	    enter_underline_mode != NULL &&
    856 	    exit_underline_mode != NULL)
    857 	{
    858 		tputs(enter_underline_mode, 0, __cputchar);
    859 		curscr->wattr |= __UNDERSCORE;
    860 	}
    861 
    862 	/*
    863 	 * Set other attributes as appropriate.
    864 	 */
    865 	if (exit_attribute_mode != NULL) {
    866 		if (on & __BLINK && enter_blink_mode != NULL)
    867 		{
    868 			tputs(enter_blink_mode, 0, __cputchar);
    869 			curscr->wattr |= __BLINK;
    870 		}
    871 		if (on & __BOLD && enter_bold_mode != NULL)
    872 		{
    873 			tputs(enter_bold_mode, 0, __cputchar);
    874 			curscr->wattr |= __BOLD;
    875 		}
    876 		if (on & __DIM && enter_dim_mode != NULL)
    877 		{
    878 			tputs(enter_dim_mode, 0, __cputchar);
    879 			curscr->wattr |= __DIM;
    880 		}
    881 		if (on & __BLANK && enter_secure_mode != NULL)
    882 		{
    883 			tputs(enter_secure_mode, 0, __cputchar);
    884 			curscr->wattr |= __BLANK;
    885 		}
    886 		if (on & __PROTECT && enter_protected_mode != NULL)
    887 		{
    888 			tputs(enter_protected_mode, 0, __cputchar);
    889 			curscr->wattr |= __PROTECT;
    890 		}
    891 		if (on & __REVERSE && enter_reverse_mode != NULL)
    892 		{
    893 			tputs(enter_reverse_mode, 0, __cputchar);
    894 			curscr->wattr |= __REVERSE;
    895 		}
    896 #ifdef HAVE_WCHAR
    897 		if (on & WA_TOP && enter_top_hl_mode != NULL)
    898 		{
    899 			tputs(enter_top_hl_mode, 0, __cputchar);
    900 			curscr->wattr |= WA_TOP;
    901 		}
    902 		if (on & WA_LOW && enter_low_hl_mode != NULL)
    903 		{
    904 			tputs(enter_low_hl_mode, 0, __cputchar);
    905 			curscr->wattr |= WA_LOW;
    906 		}
    907 		if (on & WA_LEFT && enter_left_hl_mode != NULL)
    908 		{
    909 			tputs(enter_left_hl_mode, 0, __cputchar);
    910 			curscr->wattr |= WA_LEFT;
    911 		}
    912 		if (on & WA_RIGHT && enter_right_hl_mode != NULL)
    913 		{
    914 			tputs(enter_right_hl_mode, 0, __cputchar);
    915 			curscr->wattr |= WA_RIGHT;
    916 		}
    917 		if (on & WA_HORIZONTAL && enter_horizontal_hl_mode != NULL)
    918 		{
    919 			tputs(enter_horizontal_hl_mode, 0, __cputchar);
    920 			curscr->wattr |= WA_HORIZONTAL;
    921 		}
    922 		if (on & WA_VERTICAL && enter_vertical_hl_mode != NULL)
    923 		{
    924 			tputs(enter_vertical_hl_mode, 0, __cputchar);
    925 			curscr->wattr |= WA_VERTICAL;
    926 		}
    927 #endif /* HAVE_WCHAR */
    928 	}
    929 
    930 	/* Enter/exit altcharset mode as appropriate. */
    931 	if (on & __ALTCHARSET && enter_alt_charset_mode != NULL &&
    932 	    exit_alt_charset_mode != NULL) {
    933 		tputs(enter_alt_charset_mode, 0, __cputchar);
    934 		curscr->wattr |= __ALTCHARSET;
    935 	}
    936 }
    937 
    938 static void
    939 putattr_out(__LDATA *nsp)
    940 {
    941 
    942 	if (underline_char &&
    943 	    ((nsp->attr & __STANDOUT) || (nsp->attr & __UNDERSCORE)))
    944 	{
    945 		__cputchar('\b');
    946 		tputs(underline_char, 0, __cputchar);
    947 	}
    948 }
    949 
    950 static int
    951 putch(__LDATA *nsp, __LDATA *csp, int wy, int wx)
    952 {
    953 
    954 	if (csp != NULL)
    955 		putattr(nsp);
    956 
    957 	if (!_cursesi_screen->curwin && csp) {
    958 		csp->attr = nsp->attr;
    959 		csp->ch = nsp->ch;
    960 #ifdef HAVE_WCHAR
    961 		if (_cursesi_copy_nsp(nsp->nsp, csp) == ERR)
    962 			return ERR;
    963 		csp->wcols = nsp->wcols;
    964 #endif /* HAVE_WCHAR */
    965 	}
    966 
    967 #ifndef HAVE_WCHAR
    968 	__cputchar((int)nsp->ch);
    969 #else
    970 	if (nsp->wcols <= 0)
    971 		goto out;
    972 
    973 	if (((_cursesi_screen->nca & nsp->attr) == 0) && (__using_color == 1) &&
    974 	    csp == NULL)
    975 		__set_color(curscr, nsp->attr & __COLOR);
    976 	__cputwchar((int)nsp->ch);
    977 	__CTRACE(__CTRACE_REFRESH,
    978 	    "putch: (%d,%d)putwchar(0x%x)\n", wy, wx - 1, nsp->ch);
    979 
    980 	/* Output non-spacing characters for the cell. */
    981 	__cursesi_putnsp(nsp->nsp, wy, wx);
    982 out:
    983 #endif /* HAVE_WCHAR */
    984 
    985 	if (csp != NULL)
    986 		putattr_out(nsp);
    987 	return OK;
    988 }
    989 
    990 static int
    991 putchbr(__LDATA *nsp, __LDATA *csp, __LDATA *psp, int wy, int wx)
    992 {
    993 	int error, cw, pcw;
    994 
    995 	/* Can safely print to bottom right corner. */
    996 	if (!auto_right_margin)
    997 		return putch(nsp, csp, wy, wx);
    998 
    999 	/* Disable auto margins temporarily. */
   1000 	if (enter_am_mode && exit_am_mode) {
   1001 		tputs(exit_am_mode, 0, __cputchar);
   1002 		error = putch(nsp, csp, wy, wx);
   1003 		tputs(enter_am_mode, 0, __cputchar);
   1004 		return error;
   1005 	}
   1006 
   1007 	/* We need to insert characters. */
   1008 #ifdef HAVE_WCHAR
   1009 	cw = nsp->wcols;
   1010 	pcw = psp->wcols;
   1011 	if (cw < 1 || pcw < 1)
   1012 		return ERR; /* Nothing to insert */
   1013 
   1014 	/* When inserting a wide character, we need something other than
   1015 	 * insert_character. */
   1016 	if (pcw > 1 &&
   1017 	    !(parm_ich != NULL ||
   1018 	    (enter_insert_mode != NULL && exit_insert_mode != NULL)))
   1019 		return ERR;
   1020 #else
   1021 	cw = pcw = 1;
   1022 #endif /* HAVE_WCHAR */
   1023 
   1024 	/* Write the corner character at wx - pcw. */
   1025 	__mvcur(wy, wx, wy, wx - pcw, 1);
   1026 	if (putch(nsp, csp, wy, wx) == ERR)
   1027 		return ERR;
   1028 
   1029 	/* Move cursor back. */
   1030 	__mvcur(wy, wx - pcw + cw, wy, wx - cw, 1);
   1031 
   1032 	putattr(psp);
   1033 
   1034 	/* Enter insert mode. */
   1035 	if (pcw == 1 && insert_character != NULL)
   1036 		tputs(insert_character, 0, __cputchar);
   1037 	else if (parm_ich != NULL)
   1038 		tputs(tiparm(parm_ich, (long)pcw), 0, __cputchar);
   1039 	else if (enter_insert_mode != NULL && exit_insert_mode != NULL)
   1040 		tputs(enter_insert_mode, 0, __cputchar);
   1041 	else
   1042 		return ERR;
   1043 
   1044 	/* Insert the old character back. */
   1045 	error = putch(psp, NULL, wy, wx - pcw);
   1046 
   1047 	/* Exit insert mode. */
   1048 	if (insert_character != NULL || parm_ich != NULL)
   1049 		;
   1050 	else if (enter_insert_mode != NULL && exit_insert_mode != NULL)
   1051 		tputs(exit_insert_mode, 0, __cputchar);
   1052 
   1053 	putattr_out(psp);
   1054 
   1055 	return error;
   1056 }
   1057 
   1058 /*
   1059  * makech --
   1060  *	Make a change on the screen.
   1061  */
   1062 static int
   1063 makech(int wy)
   1064 {
   1065 	WINDOW	*win;
   1066 	static __LDATA blank, space;
   1067 	__LDATA *nsp, *csp, *cp, *cep, *fsp, *tld;
   1068 	__LINE *wlp;
   1069 	size_t	clsp, nlsp;	/* Last space in lines. */
   1070 	int	lch, wx, owx, chw;
   1071 	const char	*ce;
   1072 	attr_t	lspc;		/* Last space colour */
   1073 	attr_t	battr;		/* background attribute bits */
   1074 	attr_t	attr_mask;	/* attributes mask */
   1075 
   1076 #ifdef __GNUC__
   1077 	nlsp = lspc = 0;	/* XXX gcc -Wuninitialized */
   1078 #endif
   1079 	if (_cursesi_screen->curwin)
   1080 		win = curscr;
   1081 	else
   1082 		win = __virtscr;
   1083 
   1084 	blank.ch = win->bch;
   1085 	blank.attr = win->battr;
   1086 #ifdef HAVE_WCHAR
   1087 	if (_cursesi_copy_nsp(win->bnsp, &blank) == ERR)
   1088 		return ERR;
   1089 	blank.wcols = win->wcols;
   1090 	attr_mask = WA_ATTRIBUTES;
   1091 
   1092 	space.ch = (wchar_t) btowc((int) ' ');
   1093 	space.nsp = NULL;
   1094 	space.wcols = 1;
   1095 	space.attr = WA_NORMAL;
   1096 #else
   1097 	space.ch = ' ';
   1098 	space.attr = A_NORMAL;
   1099 	attr_mask = A_ATTRIBUTES;
   1100 #endif /* HAVE_WCHAR */
   1101 	battr = win->battr & attr_mask;
   1102 
   1103 #ifdef DEBUG
   1104 #if HAVE_WCHAR
   1105 	{
   1106 		int x;
   1107 		__LDATA *lp, *vlp;
   1108 
   1109 		__CTRACE(__CTRACE_REFRESH,
   1110 		    "[makech-before]wy=%d,curscr(%p)-__virtscr(%p)\n",
   1111 		    wy, curscr, __virtscr);
   1112 		for (x = 0; x < curscr->maxx; x++) {
   1113 			lp = &curscr->alines[wy]->line[x];
   1114 			vlp = &__virtscr->alines[wy]->line[x];
   1115 			__CTRACE(__CTRACE_REFRESH,
   1116 			    "[%d,%d](%x,%x,%d,%x,%x,%d,%p)-"
   1117 			    "(%x,%x,%d,%x,%x,%d,%p)\n",
   1118 			    wy, x, lp->ch, lp->attr, lp->wcols,
   1119 			    win->bch, win->battr, win->wcols, lp->nsp,
   1120 			    vlp->ch, vlp->attr, vlp->wcols,
   1121 			    win->bch, win->battr, win->wcols, vlp->nsp);
   1122 		}
   1123 	}
   1124 #endif /* HAVE_WCHAR */
   1125 #endif /* DEBUG */
   1126 
   1127 	/* Is the cursor still on the end of the last line? */
   1128 	if (wy > 0 && curscr->alines[wy - 1]->flags & __ISPASTEOL) {
   1129 		domvcur(win, _cursesi_screen->ly, _cursesi_screen->lx,
   1130 			_cursesi_screen->ly + 1, 0);
   1131 		_cursesi_screen->ly++;
   1132 		_cursesi_screen->lx = 0;
   1133 	}
   1134 	wlp = win->alines[wy];
   1135 	wx = *win->alines[wy]->firstchp;
   1136 	if (wx < 0)
   1137 		wx = 0;
   1138 	else
   1139 		if (wx >= win->maxx)
   1140 			return (OK);
   1141 	lch = *win->alines[wy]->lastchp;
   1142 	if (lch < 0)
   1143 		return OK;
   1144 	else
   1145 		if (lch >= (int) win->maxx)
   1146 			lch = win->maxx - 1;
   1147 
   1148 	if (_cursesi_screen->curwin) {
   1149 		csp = &blank;
   1150 		__CTRACE(__CTRACE_REFRESH, "makech: csp is blank\n");
   1151 	} else {
   1152 		csp = &curscr->alines[wy]->line[wx];
   1153 		__CTRACE(__CTRACE_REFRESH,
   1154 		    "makech: csp is on curscr:(%d,%d)\n", wy, wx);
   1155 	}
   1156 
   1157 	nsp = fsp = &win->alines[wy]->line[wx];
   1158 
   1159 #ifdef DEBUG
   1160 	if (_cursesi_screen->curwin)
   1161 		__CTRACE(__CTRACE_REFRESH,
   1162 		    "makech: nsp is at curscr:(%d,%d)\n", wy, wx);
   1163 	else
   1164 		__CTRACE(__CTRACE_REFRESH,
   1165 		    "makech: nsp is at __virtscr:(%d,%d)\n", wy, wx);
   1166 #endif /* DEBUG */
   1167 
   1168 	/*
   1169 	 * Work out if we can use a clear to end of line.  If we are
   1170 	 * using color then we can only erase the line if the terminal
   1171 	 * can erase to the background color.
   1172 	 */
   1173 	if (clr_eol && !_cursesi_screen->curwin && (!(__using_color)
   1174 	    || (__using_color && back_color_erase))) {
   1175 		cp = &win->alines[wy]->line[win->maxx - 1];
   1176 #ifdef HAVE_WCHAR
   1177 		while ((celleq(cp, &space) == 1) &&
   1178 #else
   1179 		while (cp->ch == space.ch &&
   1180 #endif /* HAVE_WCHAR */
   1181 		    ((cp->attr & attr_mask) == battr)) {
   1182 			if (cp-- <= win->alines[wy]->line)
   1183 				break;
   1184 		}
   1185 
   1186 #ifdef HAVE_WCHAR
   1187 		if ((cp->wflags & WCA_CONTINUATION) == WCA_CONTINUATION)
   1188 			cp--;
   1189 #endif /* HAVE_WCHAR */
   1190 
   1191 		if (win->alines[wy]->line > cp)
   1192 			nlsp = 0;
   1193 		else
   1194 			nlsp = cp - win->alines[wy]->line;
   1195 	}
   1196 
   1197 	ce = clr_eol;
   1198 
   1199 	while (wx <= lch) {
   1200 		__CTRACE(__CTRACE_REFRESH, "makech: wx=%d,lch=%d\n", wx, lch);
   1201 #ifdef HAVE_WCHAR
   1202 		__CTRACE(__CTRACE_REFRESH, "makech: farnarkle: flags 0x%x, wflags 0x%x, color_init %d, celleq %d\n",
   1203 			wlp->flags, nsp->wflags, __do_color_init, celleq(nsp, csp));
   1204 		__CTRACE(__CTRACE_REFRESH, "makech: nsp=(%x,%x,%d,%x,%x,%d,%p)\n",
   1205 			nsp->ch, nsp->attr, nsp->wcols, win->bch, win->battr,
   1206 			win->wcols, nsp->nsp);
   1207 		__CTRACE(__CTRACE_REFRESH, "makech: csp=(%x,%x,%d,%x,%x,%d,%p)\n",
   1208 			csp->ch, csp->attr, csp->wcols, win->bch, win->battr,
   1209 			win->wcols, csp->nsp);
   1210 #endif
   1211 		if (!(wlp->flags & __ISFORCED) &&
   1212 #ifdef HAVE_WCHAR
   1213 		    ((nsp->wflags & WCA_CONTINUATION) != WCA_CONTINUATION) &&
   1214 #endif
   1215 		    celleq(nsp, csp))
   1216 		{
   1217 			if (wx <= lch) {
   1218 				while (wx <= lch && celleq(nsp, csp)) {
   1219 #ifdef HAVE_WCHAR
   1220 					wx += nsp->wcols;
   1221 #else
   1222 					wx++;
   1223 #endif
   1224 					nsp++;
   1225 					if (!_cursesi_screen->curwin)
   1226 						++csp;
   1227 				}
   1228 				continue;
   1229 			}
   1230 			break;
   1231 		}
   1232 
   1233 		domvcur(win, _cursesi_screen->ly, _cursesi_screen->lx, wy, wx);
   1234 
   1235 		__CTRACE(__CTRACE_REFRESH, "makech: 1: wx = %d, ly= %d, "
   1236 		    "lx = %d, newy = %d, newx = %d, lch = %d\n",
   1237 		    wx, _cursesi_screen->ly, _cursesi_screen->lx, wy, wx, lch);
   1238 		_cursesi_screen->ly = wy;
   1239 		_cursesi_screen->lx = wx;
   1240 		owx = wx;
   1241 		while (wx <= lch &&
   1242 		       ((wlp->flags & __ISFORCED) || !celleq(nsp, csp)))
   1243 		{
   1244 			if ((ce != NULL) && (wx >= nlsp) &&
   1245 			    (nsp->ch == space.ch) &&
   1246 			    (__do_color_init == 1 || nsp->attr == space.attr))
   1247 			{
   1248 				/* Check for clear to end-of-line. */
   1249 				cep = &curscr->alines[wy]->line[win->maxx - 1];
   1250 				while (cep->ch == blank.ch && cep->attr == battr)
   1251 					if (cep-- <= csp)
   1252 						break;
   1253 				if (cep >= (curscr->alines[wy]->line + win->begx * __LDATASIZE))
   1254 					clsp = cep - curscr->alines[wy]->line -
   1255 					    win->begx * __LDATASIZE;
   1256 				else
   1257 					clsp = 0;
   1258 				__CTRACE(__CTRACE_REFRESH,
   1259 				    "makech: clsp = %zu, nlsp = %zu, strlen(ce) = %ld\n",
   1260 				    clsp, nlsp, strlen(ce));
   1261 				__CTRACE(__CTRACE_REFRESH,
   1262 				    "makech: line = %p, cep = %p, begx = %u\n",
   1263 				    curscr->alines[wy]->line, cep, win->begx);
   1264 
   1265 				/*
   1266 				 * work out how to clear the line.  If:
   1267 				 *  - clear len is greater than clear_to_eol len
   1268 				 *  - background char == ' '
   1269 				 *  - we are not at EOL
   1270 				 *  - using color and term can erase to
   1271 				 *    background color
   1272 				 *  - if we are at the bottom of the window
   1273 				 *    (to prevent a scroll)
   1274 				 * then emit the ce string.
   1275 				 */
   1276 				if (((((clsp - nlsp > strlen(ce)) ||
   1277 				     (__do_color_init && back_color_erase)) &&
   1278 				     (clsp != win->maxx * __LDATASIZE)) ||
   1279 				     (wy == win->maxy - 1)) &&
   1280 				    (!(__using_color) ||
   1281 				     (__using_color && back_color_erase)))
   1282 				{
   1283 					if(wlp->line[wx].attr & win->screen->nca) {
   1284 						__unsetattr(0);
   1285 					} else if (__using_color &&
   1286 					    ((__do_color_init == 1) ||
   1287 					    ((lspc & __COLOR) !=
   1288 					    (curscr->wattr & __COLOR)))) {
   1289 						__set_color(curscr, lspc &
   1290 						    __COLOR);
   1291 					}
   1292 					tputs(ce, 0, __cputchar);
   1293 					_cursesi_screen->lx = wx + win->begx;
   1294 					while (wx++ <= clsp) {
   1295 						csp->attr = blank.attr;
   1296 						csp->ch = blank.ch;
   1297 #ifdef HAVE_WCHAR
   1298 						if (_cursesi_copy_nsp(blank.nsp, csp) == ERR)
   1299 							return ERR;
   1300 #endif /* HAVE_WCHAR */
   1301 						csp->wcols = blank.wcols;
   1302 						assert(csp != &blank);
   1303 						csp++;
   1304 					}
   1305 					return OK;
   1306 				}
   1307 				ce = NULL;
   1308 			}
   1309 
   1310 #ifdef HAVE_WCHAR
   1311 			chw = nsp->wcols;
   1312 			if (chw < 0)
   1313 				chw = 0; /* match putch() */
   1314 #else
   1315 			chw = 1;
   1316 #endif /* HAVE_WCHAR */
   1317 			owx = wx;
   1318 			if (wx + chw >= win->maxx &&
   1319 			    wy == win->maxy - 1 && !_cursesi_screen->curwin)
   1320 			{
   1321 				if (win->flags & __ENDLINE)
   1322 					__unsetattr(1);
   1323 				if (!(win->flags & __SCROLLWIN)) {
   1324 					int e;
   1325 
   1326 					if (win->flags & __SCROLLOK)
   1327 						e = putch(nsp, csp, wy, wx);
   1328 					else
   1329 						e = putchbr(nsp, csp,
   1330 						    nsp == fsp ? NULL : nsp - 1,
   1331 						    wy, wx);
   1332 					if (e == ERR)
   1333 						return ERR;
   1334 				}
   1335 				if (wx + chw < curscr->maxx) {
   1336 					domvcur(win,
   1337 					    _cursesi_screen->ly, wx,
   1338 					    (int)(win->maxy - 1),
   1339 					    (int)(win->maxx - 1));
   1340 				}
   1341 				_cursesi_screen->ly = win->maxy - 1;
   1342 				_cursesi_screen->lx = win->maxx - 1;
   1343 				return OK;
   1344 			}
   1345 			if (wx + chw < win->maxx || wy < win->maxy - 1 ||
   1346 			    !(win->flags & __SCROLLWIN))
   1347 			{
   1348 				tld = nsp;
   1349 				if (celleq(&blank, nsp))
   1350 					tld = &blank;
   1351 
   1352 				if (putch(tld, csp, wy, wx) == ERR)
   1353 					return ERR;
   1354 				if (!_cursesi_screen->curwin) {
   1355 					assert(csp != &blank);
   1356 					csp++;
   1357 				}
   1358 			} else {
   1359 				putattr(nsp);
   1360 				putattr_out(nsp);
   1361 			}
   1362 			wx += chw;
   1363 			nsp += chw;
   1364 			__CTRACE(__CTRACE_REFRESH,
   1365 			    "makech: 2: wx = %d, lx = %d\n",
   1366 			    wx, _cursesi_screen->lx);
   1367 		}
   1368 		if (_cursesi_screen->lx == wx)	/* If no change. */
   1369 			break;
   1370 
   1371 		/*
   1372 		 * We need to work out if the cursor has been put in the
   1373 		 * middle of a wide character so check if curx is between
   1374 		 * where we were and where we are and we are on the right
   1375 		 * line.  If so, move the cursor now.
   1376 		 */
   1377 		if ((wy == win->cury) && (wx > win->curx) &&
   1378 		    (owx < win->curx)) {
   1379 			_cursesi_screen->lx = win->curx;
   1380 			domvcur(win, _cursesi_screen->ly, wx,
   1381 			    _cursesi_screen->ly, _cursesi_screen->lx);
   1382 		} else
   1383 			_cursesi_screen->lx = wx;
   1384 
   1385 		if (_cursesi_screen->lx >= COLS && auto_right_margin)
   1386 			_cursesi_screen->lx = COLS - 1;
   1387 		else
   1388 			if (wx >= win->maxx) {
   1389 				domvcur(win,
   1390 					_cursesi_screen->ly,
   1391 					_cursesi_screen->lx,
   1392 					_cursesi_screen->ly,
   1393 					(int)(win->maxx - 1));
   1394 				_cursesi_screen->lx = win->maxx - 1;
   1395 			}
   1396 		__CTRACE(__CTRACE_REFRESH, "makech: 3: wx = %d, lx = %d\n",
   1397 		    wx, _cursesi_screen->lx);
   1398 	}
   1399 #ifdef DEBUG
   1400 #if HAVE_WCHAR
   1401 	{
   1402 		int x;
   1403 		__LDATA *lp, *vlp;
   1404 
   1405 		__CTRACE(__CTRACE_REFRESH,
   1406 		    "makech-after: curscr(%p)-__virtscr(%p)\n",
   1407 		    curscr, __virtscr );
   1408 		for (x = 0; x < curscr->maxx; x++) {
   1409 			lp = &curscr->alines[wy]->line[x];
   1410 			vlp = &__virtscr->alines[wy]->line[x];
   1411 			__CTRACE(__CTRACE_REFRESH,
   1412 			    "[%d,%d](%x,%x,%d,%x,%x,%d,%p)-"
   1413 			    "(%x,%x,%d,%x,%x,%d,%p)\n",
   1414 			    wy, x, lp->ch, lp->attr, lp->wcols,
   1415 			    win->bch, win->battr, win->wcols, lp->nsp,
   1416 			    vlp->ch, vlp->attr, vlp->wcols,
   1417 			    win->bch, win->battr, win->wcols, vlp->nsp);
   1418 		}
   1419 	}
   1420 #endif /* HAVE_WCHAR */
   1421 #endif /* DEBUG */
   1422 
   1423 	return OK;
   1424 }
   1425 
   1426 /*
   1427  * domvcur --
   1428  *	Do a mvcur, leaving attributes if necessary.
   1429  */
   1430 static void
   1431 domvcur(WINDOW *win, int oy, int ox, int ny, int nx)
   1432 {
   1433 
   1434 	__CTRACE(__CTRACE_REFRESH, "domvcur: (%d,%d)=>(%d,%d) win %p\n",
   1435 	    oy, ox, ny, nx, win );
   1436 
   1437 	__unsetattr(1);
   1438 
   1439 	/* Don't move the cursor unless we need to. */
   1440 	if (oy == ny && ox == nx) {
   1441 		/* Check EOL. */
   1442 		if (!(win->alines[oy]->flags & __ISPASTEOL))
   1443 			return;
   1444 	}
   1445 
   1446 	/* Clear EOL flags. */
   1447 	win->alines[oy]->flags &= ~__ISPASTEOL;
   1448 	win->alines[ny]->flags &= ~__ISPASTEOL;
   1449 
   1450 	__mvcur(oy, ox, ny, nx, 1);
   1451 }
   1452 
   1453 /*
   1454  * Quickch() attempts to detect a pattern in the change of the window
   1455  * in order to optimize the change, e.g., scroll n lines as opposed to
   1456  * repainting the screen line by line.
   1457  */
   1458 
   1459 static __LDATA buf[128];
   1460 static  unsigned int last_hash;
   1461 static  size_t last_hash_len;
   1462 #define BLANKSIZE (sizeof(buf) / sizeof(buf[0]))
   1463 
   1464 static void
   1465 quickch(void)
   1466 {
   1467 #define THRESH		(int) __virtscr->maxy / 4
   1468 
   1469 	__LINE *clp, *tmp1, *tmp2;
   1470 	int	bsize, curs, curw, starts, startw, i, j;
   1471 	int	n, target, cur_period, bot, top, sc_region;
   1472 	unsigned int	blank_hash, found;
   1473 	attr_t	bcolor;
   1474 
   1475 #ifdef __GNUC__
   1476 	curs = curw = starts = startw = 0;	/* XXX gcc -Wuninitialized */
   1477 #endif
   1478 	/*
   1479 	 * Find how many lines from the top of the screen are unchanged.
   1480 	 */
   1481 	for (top = 0; top < __virtscr->maxy; top++) {
   1482 		if (__virtscr->alines[top]->flags & __ISDIRTY &&
   1483 		    (__virtscr->alines[top]->hash != curscr->alines[top]->hash ||
   1484 		     !lineeq(__virtscr->alines[top]->line,
   1485 			     curscr->alines[top]->line,
   1486 			     (size_t) __virtscr->maxx))) {
   1487 			break;
   1488 		} else
   1489 			__virtscr->alines[top]->flags &= ~__ISDIRTY;
   1490 	}
   1491 	/*
   1492 	 * Find how many lines from bottom of screen are unchanged.
   1493 	 */
   1494 	for (bot = __virtscr->maxy - 1; bot >= 0; bot--) {
   1495 		if (__virtscr->alines[bot]->flags & __ISDIRTY &&
   1496 		    (__virtscr->alines[bot]->hash != curscr->alines[bot]->hash ||
   1497 		     !lineeq(__virtscr->alines[bot]->line,
   1498 			     curscr->alines[bot]->line,
   1499 			     (size_t) __virtscr->maxx))) {
   1500 			break;
   1501 		} else
   1502 			__virtscr->alines[bot]->flags &= ~__ISDIRTY;
   1503 	}
   1504 
   1505 	/*
   1506 	 * Work round an xterm bug where inserting lines causes all the
   1507 	 * inserted lines to be covered with the background colour we
   1508 	 * set on the first line (even if we unset it for subsequent
   1509 	 * lines).
   1510 	 */
   1511 	bcolor = __virtscr->alines[min(top,
   1512 	    __virtscr->maxy - 1)]->line[0].attr & __COLOR;
   1513 	for (i = top + 1, j = 0; i < bot; i++) {
   1514 		if ((__virtscr->alines[i]->line[0].attr & __COLOR) != bcolor) {
   1515 			bcolor = __virtscr->alines[i]->line[__virtscr->maxx].
   1516 			    attr & __COLOR;
   1517 			j = i - top;
   1518 		} else
   1519 			break;
   1520 	}
   1521 	top += j;
   1522 
   1523 #ifdef NO_JERKINESS
   1524 	/*
   1525 	 * If we have a bottom unchanged region return.  Scrolling the
   1526 	 * bottom region up and then back down causes a screen jitter.
   1527 	 * This will increase the number of characters sent to the screen
   1528 	 * but it looks better.
   1529 	 */
   1530 	if (bot < __virtscr->maxy - 1)
   1531 		return;
   1532 #endif				/* NO_JERKINESS */
   1533 
   1534 	/*
   1535 	 * Search for the largest block of text not changed.
   1536 	 * Invariants of the loop:
   1537 	 * - Startw is the index of the beginning of the examined block in
   1538 	 *   __virtscr.
   1539 	 * - Starts is the index of the beginning of the examined block in
   1540 	 *   curscr.
   1541 	 * - Curw is the index of one past the end of the exmined block in
   1542 	 *   __virtscr.
   1543 	 * - Curs is the index of one past the end of the exmined block in
   1544 	 *   curscr.
   1545 	 * - bsize is the current size of the examined block.
   1546 	*/
   1547 
   1548 	found = 0;
   1549 	for (bsize = bot - top; bsize >= THRESH; bsize--) {
   1550 		for (startw = top; startw <= bot - bsize; startw++)
   1551 			for (starts = top; starts <= bot - bsize; starts++) {
   1552 /*				for (curw = startw, curs = starts;
   1553 				    curs < starts + bsize; curw++, curs++)
   1554 					if (__virtscr->alines[curw]->hash !=
   1555 					    curscr->alines[curs]->hash)
   1556 						break;
   1557 				if (curs != starts + bsize)
   1558 					continue;*/
   1559 				for (curw = startw, curs = starts;
   1560 					curs < starts + bsize; curw++, curs++)
   1561 					if (!lineeq(__virtscr->alines[curw]->line,
   1562 						    curscr->alines[curs]->line,
   1563 						    (size_t) __virtscr->maxx)) {
   1564 						found = 1;
   1565 						break;
   1566 				}
   1567 				if ((curs == starts + bsize) && (found == 1)) {
   1568 					goto done;
   1569 				}
   1570 			}
   1571 	}
   1572 done:
   1573 
   1574 	__CTRACE(__CTRACE_REFRESH, "quickch:bsize=%d, THRESH=%d, starts=%d, "
   1575 	    "startw=%d, curw=%d, curs=%d, top=%d, bot=%d\n",
   1576 	    bsize, THRESH, starts, startw, curw, curs, top, bot);
   1577 
   1578 	/* Did not find anything */
   1579 	if (bsize < THRESH)
   1580 		return;
   1581 
   1582 	/*
   1583 	 * Make sure that there is no overlap between the bottom and top
   1584 	 * regions and the middle scrolled block.
   1585 	 */
   1586 	if (bot < curs)
   1587 		bot = curs - 1;
   1588 	if (top > starts)
   1589 		top = starts;
   1590 
   1591 	n = startw - starts;
   1592 
   1593 #ifdef DEBUG
   1594 	__CTRACE(__CTRACE_REFRESH, "#####################################\n");
   1595 	__CTRACE(__CTRACE_REFRESH, "quickch: n = %d\n", n);
   1596 	for (i = 0; i < curscr->maxy; i++) {
   1597 		__CTRACE(__CTRACE_REFRESH, "C: %d:", i);
   1598 		__CTRACE(__CTRACE_REFRESH, " 0x%x \n", curscr->alines[i]->hash);
   1599 		for (j = 0; j < curscr->maxx; j++)
   1600 			__CTRACE(__CTRACE_REFRESH, "%c",
   1601 			    curscr->alines[i]->line[j].ch);
   1602 		__CTRACE(__CTRACE_REFRESH, "\n");
   1603 		__CTRACE(__CTRACE_REFRESH, " attr:");
   1604 		for (j = 0; j < curscr->maxx; j++)
   1605 			__CTRACE(__CTRACE_REFRESH, " %x",
   1606 			    curscr->alines[i]->line[j].attr);
   1607 		__CTRACE(__CTRACE_REFRESH, "\n");
   1608 		__CTRACE(__CTRACE_REFRESH, "W: %d:", i);
   1609 		__CTRACE(__CTRACE_REFRESH, " 0x%x \n",
   1610 		    __virtscr->alines[i]->hash);
   1611 		__CTRACE(__CTRACE_REFRESH, " 0x%x ",
   1612 		    __virtscr->alines[i]->flags);
   1613 		for (j = 0; j < __virtscr->maxx; j++)
   1614 			__CTRACE(__CTRACE_REFRESH, "%c",
   1615 			    __virtscr->alines[i]->line[j].ch);
   1616 		__CTRACE(__CTRACE_REFRESH, "\n");
   1617 		__CTRACE(__CTRACE_REFRESH, " attr:");
   1618 		for (j = 0; j < __virtscr->maxx; j++)
   1619 			__CTRACE(__CTRACE_REFRESH, " %x",
   1620 			    __virtscr->alines[i]->line[j].attr);
   1621 		__CTRACE(__CTRACE_REFRESH, "\n");
   1622 	}
   1623 #endif
   1624 
   1625 #ifndef HAVE_WCHAR
   1626 	if (buf[0].ch != curscr->bch) {
   1627 		for (i = 0; i < BLANKSIZE; i++) {
   1628 			buf[i].ch = curscr->bch;
   1629 			buf[i].attr = 0;
   1630 		}
   1631 	}
   1632 #else
   1633 	if (buf[0].ch != curscr->bch) {
   1634 		for (i = 0; i < BLANKSIZE; i++) { /* XXXX: BLANKSIZE may not be valid if wcols > 1 */
   1635 			buf[i].ch = curscr->bch;
   1636 			if (_cursesi_copy_nsp(curscr->bnsp, &buf[i]) == ERR)
   1637 				return;
   1638 			buf[i].attr = 0;
   1639 			buf[i].wcols = curscr->wcols;
   1640 		}
   1641 	}
   1642 #endif /* HAVE_WCHAR */
   1643 
   1644 	if (__virtscr->maxx != last_hash_len) {
   1645 		blank_hash = 0;
   1646 		for (i = __virtscr->maxx; i > BLANKSIZE; i -= BLANKSIZE) {
   1647 			blank_hash = __hash_more(buf, sizeof(buf), blank_hash);
   1648 		}
   1649 		blank_hash = __hash_more((char *)(void *)buf,
   1650 		    i * sizeof(buf[0]), blank_hash);
   1651 		/* cache result in static data - screen width doesn't change often */
   1652 		last_hash_len = __virtscr->maxx;
   1653 		last_hash = blank_hash;
   1654 	} else
   1655 		blank_hash = last_hash;
   1656 
   1657 	/*
   1658 	 * Perform the rotation to maintain the consistency of curscr.
   1659 	 * This is hairy since we are doing an *in place* rotation.
   1660 	 * Invariants of the loop:
   1661 	 * - I is the index of the current line.
   1662 	 * - Target is the index of the target of line i.
   1663 	 * - Tmp1 points to current line (i).
   1664 	 * - Tmp2 and points to target line (target);
   1665 	 * - Cur_period is the index of the end of the current period.
   1666 	 *   (see below).
   1667 	 *
   1668 	 * There are 2 major issues here that make this rotation non-trivial:
   1669 	 * 1.  Scrolling in a scrolling region bounded by the top
   1670 	 *     and bottom regions determined (whose size is sc_region).
   1671 	 * 2.  As a result of the use of the mod function, there may be a
   1672 	 *     period introduced, i.e., 2 maps to 4, 4 to 6, n-2 to 0, and
   1673 	 *     0 to 2, which then causes all odd lines not to be rotated.
   1674 	 *     To remedy this, an index of the end ( = beginning) of the
   1675 	 *     current 'period' is kept, cur_period, and when it is reached,
   1676 	 *     the next period is started from cur_period + 1 which is
   1677 	 *     guaranteed not to have been reached since that would mean that
   1678 	 *     all records would have been reached. (think about it...).
   1679 	 *
   1680 	 * Lines in the rotation can have 3 attributes which are marked on the
   1681 	 * line so that curscr is consistent with the visual screen.
   1682 	 * 1.  Not dirty -- lines inside the scrolled block, top region or
   1683 	 *                  bottom region.
   1684 	 * 2.  Blank lines -- lines in the differential of the scrolling
   1685 	 *		      region adjacent to top and bot regions
   1686 	 *                    depending on scrolling direction.
   1687 	 * 3.  Dirty line -- all other lines are marked dirty.
   1688 	 */
   1689 	sc_region = bot - top + 1;
   1690 	i = top;
   1691 	tmp1 = curscr->alines[top];
   1692 	cur_period = top;
   1693 	for (j = top; j <= bot; j++) {
   1694 		target = (i - top + n + sc_region) % sc_region + top;
   1695 		tmp2 = curscr->alines[target];
   1696 		curscr->alines[target] = tmp1;
   1697 		/* Mark block as clean and blank out scrolled lines. */
   1698 		clp = curscr->alines[target];
   1699 		__CTRACE(__CTRACE_REFRESH,
   1700 		    "quickch: n=%d startw=%d curw=%d i = %d target=%d ",
   1701 		    n, startw, curw, i, target);
   1702 		if ((target >= startw && target < curw) || target < top
   1703 		    || target > bot)
   1704 		{
   1705 			__CTRACE(__CTRACE_REFRESH, " notdirty\n");
   1706 			__virtscr->alines[target]->flags &= ~__ISDIRTY;
   1707 		} else
   1708 			if ((n > 0 && target >= top && target < top + n) ||
   1709 			    (n < 0 && target <= bot && target > bot + n))
   1710 			{
   1711 				if (clp->hash != blank_hash ||
   1712 				    !lineeq(clp->line, clp->line + 1,
   1713 					    (__virtscr->maxx - 1)) ||
   1714 				    !celleq(clp->line, buf))
   1715 				{
   1716 					for (i = __virtscr->maxx;
   1717 					    i > BLANKSIZE;
   1718 					    i -= BLANKSIZE) {
   1719 						(void) memcpy(clp->line + i -
   1720 						    BLANKSIZE, buf, sizeof(buf));
   1721 					}
   1722 					(void)memcpy(clp->line, buf,
   1723 					    i * sizeof(buf[0]));
   1724 					__CTRACE(__CTRACE_REFRESH,
   1725 					    " blanked out: dirty\n");
   1726 					clp->hash = blank_hash;
   1727 					__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
   1728 				} else {
   1729 					__CTRACE(__CTRACE_REFRESH,
   1730 					    " -- blank line already: dirty\n");
   1731 					__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
   1732 				}
   1733 			} else {
   1734 				__CTRACE(__CTRACE_REFRESH, " -- dirty\n");
   1735 				__touchline(__virtscr, target, 0,
   1736 				    (int)__virtscr->maxx - 1);
   1737 			}
   1738 		if (target == cur_period) {
   1739 			i = target + 1;
   1740 			tmp1 = curscr->alines[i];
   1741 			cur_period = i;
   1742 		} else {
   1743 			tmp1 = tmp2;
   1744 			i = target;
   1745 		}
   1746 	}
   1747 #ifdef DEBUG
   1748 	__CTRACE(__CTRACE_REFRESH, "$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$\n");
   1749 	for (i = 0; i < curscr->maxy; i++) {
   1750 		__CTRACE(__CTRACE_REFRESH, "C: %d:", i);
   1751 		for (j = 0; j < curscr->maxx; j++)
   1752 			__CTRACE(__CTRACE_REFRESH, "%c",
   1753 			    curscr->alines[i]->line[j].ch);
   1754 		__CTRACE(__CTRACE_REFRESH, "\n");
   1755 		__CTRACE(__CTRACE_REFRESH, "W: %d:", i);
   1756 		for (j = 0; j < __virtscr->maxx; j++)
   1757 			__CTRACE(__CTRACE_REFRESH, "%c",
   1758 			    __virtscr->alines[i]->line[j].ch);
   1759 		__CTRACE(__CTRACE_REFRESH, "\n");
   1760 	}
   1761 #endif
   1762 	if (n != 0)
   1763 		scrolln(starts, startw, curs, bot, top);
   1764 }
   1765 
   1766 /*
   1767  * scrolln --
   1768  *	Scroll n lines, where n is starts - startw.
   1769  */
   1770 static void /* ARGSUSED */
   1771 scrolln(int starts, int startw, int curs, int bot, int top)
   1772 {
   1773 	int	i, oy, ox, n;
   1774 
   1775 	oy = curscr->cury;
   1776 	ox = curscr->curx;
   1777 	n = starts - startw;
   1778 
   1779 	/*
   1780 	 * XXX
   1781 	 * The initial tests that set __noqch don't let us reach here unless
   1782 	 * we have either cs + ho + SF/sf/SR/sr, or AL + DL.  SF/sf and SR/sr
   1783 	 * scrolling can only shift the entire scrolling region, not just a
   1784 	 * part of it, which means that the quickch() routine is going to be
   1785 	 * sadly disappointed in us if we don't have cs as well.
   1786 	 *
   1787 	 * If cs, ho and SF/sf are set, can use the scrolling region.  Because
   1788 	 * the cursor position after cs is undefined, we need ho which gives us
   1789 	 * the ability to move to somewhere without knowledge of the current
   1790 	 * location of the cursor.  Still call __mvcur() anyway, to update its
   1791 	 * idea of where the cursor is.
   1792 	 *
   1793 	 * When the scrolling region has been set, the cursor has to be at the
   1794 	 * last line of the region to make the scroll happen.
   1795 	 *
   1796 	 * Doing SF/SR or AL/DL appears faster on the screen than either sf/sr
   1797 	 * or AL/DL, and, some terminals have AL/DL, sf/sr, and cs, but not
   1798 	 * SF/SR.  So, if we're scrolling almost all of the screen, try and use
   1799 	 * AL/DL, otherwise use the scrolling region.  The "almost all" is a
   1800 	 * shameless hack for vi.
   1801 	 */
   1802 	if (n > 0) {
   1803 		if (change_scroll_region != NULL && cursor_home != NULL &&
   1804 		    (parm_index != NULL ||
   1805 		    ((parm_insert_line == NULL || parm_delete_line == NULL ||
   1806 		    top > 3 || bot + 3 < __virtscr->maxy) &&
   1807 		    scroll_forward != NULL)))
   1808 		{
   1809 			tputs(tiparm(change_scroll_region, top, bot),
   1810 			    0, __cputchar);
   1811 			__mvcur(oy, ox, 0, 0, 1);
   1812 			tputs(cursor_home, 0, __cputchar);
   1813 			__mvcur(0, 0, bot, 0, 1);
   1814 			if (parm_index != NULL)
   1815 				tputs(tiparm(parm_index, n),
   1816 				    0, __cputchar);
   1817 			else
   1818 				for (i = 0; i < n; i++)
   1819 					tputs(scroll_forward, 0, __cputchar);
   1820 			tputs(tiparm(change_scroll_region,
   1821 			    0, (int)__virtscr->maxy - 1), 0, __cputchar);
   1822 			__mvcur(bot, 0, 0, 0, 1);
   1823 			tputs(cursor_home, 0, __cputchar);
   1824 			__mvcur(0, 0, oy, ox, 1);
   1825 			return;
   1826 		}
   1827 
   1828 		/* Scroll up the block. */
   1829 		if (parm_index != NULL && top == 0) {
   1830 			__mvcur(oy, ox, bot, 0, 1);
   1831 			tputs(tiparm(parm_index, n), 0, __cputchar);
   1832 		} else
   1833 			if (parm_delete_line != NULL) {
   1834 				__mvcur(oy, ox, top, 0, 1);
   1835 				tputs(tiparm(parm_delete_line, n),
   1836 				    0, __cputchar);
   1837 			} else
   1838 				if (delete_line != NULL) {
   1839 					__mvcur(oy, ox, top, 0, 1);
   1840 					for (i = 0; i < n; i++)
   1841 						tputs(delete_line, 0,
   1842 						    __cputchar);
   1843 				} else
   1844 					if (scroll_forward != NULL && top == 0) {
   1845 						__mvcur(oy, ox, bot, 0, 1);
   1846 						for (i = 0; i < n; i++)
   1847 							tputs(scroll_forward, 0,
   1848 							    __cputchar);
   1849 					} else
   1850 						abort();
   1851 
   1852 		/* Push down the bottom region. */
   1853 		__mvcur(top, 0, bot - n + 1, 0, 1);
   1854 		if (parm_insert_line != NULL)
   1855 			tputs(tiparm(parm_insert_line, n), 0, __cputchar);
   1856 		else {
   1857 			if (insert_line != NULL) {
   1858 				for (i = 0; i < n; i++)
   1859 					tputs(insert_line, 0, __cputchar);
   1860 			} else
   1861 				abort();
   1862 		}
   1863 		__mvcur(bot - n + 1, 0, oy, ox, 1);
   1864 	} else {
   1865 		/*
   1866 		 * !!!
   1867 		 * n < 0
   1868 		 *
   1869 		 * If cs, ho and SR/sr are set, can use the scrolling region.
   1870 		 * See the above comments for details.
   1871 		 */
   1872 		if (change_scroll_region != NULL && cursor_home != NULL &&
   1873 		    (parm_rindex != NULL ||
   1874 		    ((parm_insert_line == NULL || parm_delete_line == NULL ||
   1875 		    top > 3 ||
   1876 		    bot + 3 < __virtscr->maxy) && scroll_reverse != NULL)))
   1877 		{
   1878 			tputs(tiparm(change_scroll_region, top, bot),
   1879 			    0, __cputchar);
   1880 			__mvcur(oy, ox, 0, 0, 1);
   1881 			tputs(cursor_home, 0, __cputchar);
   1882 			__mvcur(0, 0, top, 0, 1);
   1883 
   1884 			if (parm_rindex != NULL)
   1885 				tputs(tiparm(parm_rindex, -n),
   1886 				    0, __cputchar);
   1887 			else
   1888 				for (i = n; i < 0; i++)
   1889 					tputs(scroll_reverse, 0, __cputchar);
   1890 			tputs(tiparm(change_scroll_region,
   1891 			    0, (int) __virtscr->maxy - 1), 0, __cputchar);
   1892 			__mvcur(top, 0, 0, 0, 1);
   1893 			tputs(cursor_home, 0, __cputchar);
   1894 			__mvcur(0, 0, oy, ox, 1);
   1895 			return;
   1896 		}
   1897 
   1898 		/* Preserve the bottom lines. */
   1899 		__mvcur(oy, ox, bot + n + 1, 0, 1);
   1900 		if (parm_rindex != NULL && bot == __virtscr->maxy)
   1901 			tputs(tiparm(parm_rindex, -n), 0, __cputchar);
   1902 		else {
   1903 			if (parm_delete_line != NULL)
   1904 				tputs(tiparm(parm_delete_line, -n),
   1905 				    0, __cputchar);
   1906 			else {
   1907 				if (delete_line != NULL)
   1908 					for (i = n; i < 0; i++)
   1909 						tputs(delete_line,
   1910 						    0, __cputchar);
   1911 				else {
   1912 					if (scroll_reverse != NULL &&
   1913 					    bot == __virtscr->maxy)
   1914 						for (i = n; i < 0; i++)
   1915 							tputs(scroll_reverse, 0,
   1916 							    __cputchar);
   1917 					else
   1918 						abort();
   1919 				}
   1920 			}
   1921 		}
   1922 		/* Scroll the block down. */
   1923 		__mvcur(bot + n + 1, 0, top, 0, 1);
   1924 		if (parm_insert_line != NULL)
   1925 			tputs(tiparm(parm_insert_line, -n), 0, __cputchar);
   1926 		else
   1927 			if (insert_line != NULL)
   1928 				for (i = n; i < 0; i++)
   1929 					tputs(insert_line, 0, __cputchar);
   1930 			else
   1931 				abort();
   1932 		__mvcur(top, 0, oy, ox, 1);
   1933 	}
   1934 }
   1935 
   1936 /*
   1937  * __unsetattr --
   1938  *	Unset attributes on curscr.  Leave standout, attribute and colour
   1939  *	modes if necessary (!ms).  Always leave altcharset (xterm at least
   1940  *	ignores a cursor move if we don't).
   1941  */
   1942 void /* ARGSUSED */
   1943 __unsetattr(int checkms)
   1944 {
   1945 	int	isms;
   1946 
   1947 	if (checkms) {
   1948 		if (!move_standout_mode)
   1949 			isms = 1;
   1950 		else
   1951 			isms = 0;
   1952 	} else
   1953 		isms = 1;
   1954 	__CTRACE(__CTRACE_REFRESH,
   1955 	    "__unsetattr: checkms = %d, ms = %s, wattr = %08x\n",
   1956 	    checkms, move_standout_mode ? "TRUE" : "FALSE", curscr->wattr);
   1957 
   1958 	/*
   1959 	 * Don't leave the screen in standout mode (check against ms).  Check
   1960 	 * to see if we also turn off underscore, attributes and colour.
   1961 	 */
   1962 	if (curscr->wattr & __STANDOUT && isms) {
   1963 		tputs(exit_standout_mode, 0, __cputchar);
   1964 		curscr->wattr &= __mask_se;
   1965 	}
   1966 	/*
   1967 	 * Don't leave the screen in underscore mode (check against ms).
   1968 	 * Check to see if we also turn off attributes.  Assume that we
   1969 	 * also turn off colour.
   1970 	 */
   1971 	if (curscr->wattr & __UNDERSCORE && isms) {
   1972 		tputs(exit_underline_mode, 0, __cputchar);
   1973 		curscr->wattr &= __mask_ue;
   1974 	}
   1975 	/*
   1976 	 * Don't leave the screen with attributes set (check against ms).
   1977 	 * Assume that also turn off colour.
   1978 	 */
   1979 	if (curscr->wattr & __TERMATTR && isms) {
   1980 		tputs(exit_attribute_mode, 0, __cputchar);
   1981 		curscr->wattr &= __mask_me;
   1982 	}
   1983 	/* Don't leave the screen with altcharset set (don't check ms). */
   1984 	if (curscr->wattr & __ALTCHARSET) {
   1985 		tputs(exit_alt_charset_mode, 0, __cputchar);
   1986 		curscr->wattr &= ~__ALTCHARSET;
   1987 	}
   1988 	/* Don't leave the screen with colour set (check against ms). */
   1989 	if (__using_color && isms)
   1990 		__unset_color(curscr);
   1991 }
   1992 
   1993 /* compare two cells on screen, must have the same foreground/background,
   1994  * and for wide characters the same sequence of non-spacing characters
   1995  */
   1996 static int
   1997 celleq(__LDATA *x, __LDATA *y)
   1998 {
   1999 #ifdef HAVE_WCHAR
   2000 	nschar_t *xnp = x->nsp, *ynp = y->nsp;
   2001 #endif /* HAVE_WCHAR */
   2002 	int ret = ( x->ch == y->ch ) && ( x->attr == y->attr );
   2003 
   2004 #ifdef HAVE_WCHAR
   2005 	if (!ret)
   2006 		return 0;
   2007 
   2008 	if (!xnp && !ynp)
   2009 		return 1;
   2010 
   2011 	if ((xnp && !ynp) || (!xnp && ynp))
   2012 		return 0;
   2013 
   2014 	while (xnp && ynp) {
   2015 		if (xnp->ch != ynp->ch)
   2016 			return 0;
   2017 		xnp = xnp->next;
   2018 		ynp = ynp->next;
   2019 	}
   2020 
   2021 	return !xnp && !ynp;
   2022 #else
   2023 	return ret;
   2024 #endif /* HAVE_WCHAR */
   2025 }
   2026 
   2027 /* compare two line segments */
   2028 static int
   2029 lineeq(__LDATA *xl, __LDATA *yl, size_t len)
   2030 {
   2031 	int i = 0;
   2032 	__LDATA *xp = xl, *yp = yl;
   2033 
   2034 	for (i = 0; i < len; i++, xp++, yp++) {
   2035 		if (!celleq(xp, yp))
   2036 			return 0;
   2037 	}
   2038 	return 1;
   2039 }
   2040 
   2041 #ifdef HAVE_WCHAR
   2042 /*
   2043  * Output the non-spacing characters associated with the given character
   2044  * cell to the screen.
   2045  */
   2046 
   2047 void
   2048 __cursesi_putnsp(nschar_t *nsp, const int wy, const int wx)
   2049 {
   2050 	nschar_t *p;
   2051 
   2052 	/* this shuts up gcc warnings about wx and wy not being used */
   2053 	if (wx > wy) {
   2054 	}
   2055 
   2056 	p = nsp;
   2057 	while (p != NULL) {
   2058 		__cputwchar((int)p->ch);
   2059 		__CTRACE(__CTRACE_REFRESH,
   2060 		    "_cursesi_putnsp: (%d,%d) non-spacing putwchar(0x%x)\n",
   2061 		    wy, wx - 1, p->ch);
   2062 		p = p->next;
   2063 	}
   2064 }
   2065 
   2066 #endif /* HAVE_WCHAR */
   2067