xref: /netbsd-src/lib/libcurses/refresh.c (revision b5677b36047b601b9addaaa494a58ceae82c2a6c)
1 /*	$NetBSD: refresh.c,v 1.70 2008/06/13 03:18:04 yamt 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 1.70 2008/06/13 03:18:04 yamt Exp $");
38 #endif
39 #endif				/* not lint */
40 
41 #include <stdlib.h>
42 #include <string.h>
43 
44 #include "curses.h"
45 #include "curses_private.h"
46 
47 static void	domvcur(int, int, int, int);
48 static int	makech(int);
49 static void	quickch(void);
50 static void	scrolln(int, int, int, int, int);
51 
52 static int _cursesi_wnoutrefresh(SCREEN *, WINDOW *,
53 				 int, int, int, int, int, int);
54 
55 #ifdef HAVE_WCHAR
56 int cellcmp( __LDATA *, __LDATA * );
57 int linecmp( __LDATA *, __LDATA *, size_t );
58 #endif /* HAVE_WCHAR */
59 
60 #ifndef _CURSES_USE_MACROS
61 
62 /*
63  * refresh --
64  *	Make the current screen look like "stdscr" over the area covered by
65  *	stdscr.
66  */
67 int
68 refresh(void)
69 {
70 	return wrefresh(stdscr);
71 }
72 
73 #endif
74 
75 /*
76  * wnoutrefresh --
77  *	Add the contents of "win" to the virtual window.
78  */
79 int
80 wnoutrefresh(WINDOW *win)
81 {
82 #ifdef DEBUG
83 	__CTRACE(__CTRACE_REFRESH, "wnoutrefresh: win %p\n", win);
84 #endif
85 
86 	return _cursesi_wnoutrefresh(_cursesi_screen, win, 0, 0, win->begy,
87 	    win->begx, win->maxy, win->maxx);
88 }
89 
90 /*
91  * pnoutrefresh --
92  *	Add the contents of "pad" to the virtual window.
93  */
94 int
95 pnoutrefresh(WINDOW *pad, int pbegy, int pbegx, int sbegy, int sbegx,
96 	int smaxy, int smaxx)
97 {
98 	int pmaxy, pmaxx;
99 
100 #ifdef DEBUG
101 	__CTRACE(__CTRACE_REFRESH, "pnoutrefresh: pad %p, flags 0x%08x\n",
102 	    pad, pad->flags);
103 	__CTRACE(__CTRACE_REFRESH,
104 	    "pnoutrefresh: (%d, %d), (%d, %d), (%d, %d)\n",
105 	    pbegy, pbegx, sbegy, sbegx, smaxy, smaxx);
106 #endif
107 
108 	/* SUS says if these are negative, they should be treated as zero */
109 	if (pbegy < 0)
110 		pbegy = 0;
111 	if (pbegx < 0)
112 		pbegx = 0;
113 	if (sbegy < 0)
114 		sbegy = 0;
115 	if (sbegx < 0)
116 		sbegx = 0;
117 
118 	/* Calculate rectangle on pad - used by _cursesi_wnoutrefresh */
119 	pmaxy = pbegy + smaxy - sbegy + 1;
120 	pmaxx = pbegx + smaxx - sbegx + 1;
121 
122 	/* Check rectangle fits in pad */
123 	if (pmaxy > pad->maxy - pad->begy)
124 		pmaxy = pad->maxy - pad->begy;
125 	if (pmaxx > pad->maxx - pad->begx)
126 		pmaxx = pad->maxx - pad->begx;
127 
128 	if (smaxy - sbegy < 0 || smaxx - sbegx < 0 )
129 		return ERR;
130 
131 	return _cursesi_wnoutrefresh(_cursesi_screen, pad,
132 	    pad->begy + pbegy, pad->begx + pbegx, pad->begy + sbegy,
133 	    pad->begx + sbegx, pmaxy, pmaxx);
134 }
135 
136 /*
137  * _cursesi_wnoutrefresh --
138  *	Does the grunt work for wnoutrefresh to the given screen.
139  *	Copies the part of the window given by the rectangle
140  *	(begy, begx) to (maxy, maxx) at screen position (wbegy, wbegx).
141  */
142 int
143 _cursesi_wnoutrefresh(SCREEN *screen, WINDOW *win, int begy, int begx,
144 	int wbegy, int wbegx, int maxy, int maxx)
145 {
146 
147 	short	sy, wy, wx, y_off, x_off, mx;
148 	__LINE	*wlp, *vlp;
149 	WINDOW	*sub_win, *orig;
150 
151 #ifdef DEBUG
152 	__CTRACE(__CTRACE_REFRESH, "_wnoutrefresh: win %p, flags 0x%08x\n",
153 	    win, win->flags);
154 	__CTRACE(__CTRACE_REFRESH,
155 	    "_wnoutrefresh: (%d, %d), (%d, %d), (%d, %d)\n",
156 	    begy, begx, wbegy, wbegx, maxy, maxx);
157 #endif
158 
159 	if (screen->curwin)
160 		return OK;
161 
162 	/*
163 	 * Recurse through any sub-windows, mark as dirty lines on the parent
164 	 * window that are dirty on the sub-window and clear the dirty flag on
165 	 * the sub-window.
166 	 */
167 	if (win->orig == 0) {
168 		orig = win;
169 		for (sub_win = win->nextp; sub_win != win;
170 		    sub_win = sub_win->nextp) {
171 #ifdef DEBUG
172 			__CTRACE(__CTRACE_REFRESH,
173 			    "wnout_refresh: win %p, sub_win %p\n",
174 			    orig, sub_win);
175 #endif
176 			for (sy = 0; sy < sub_win->maxy; sy++) {
177 				if (sub_win->lines[sy]->flags == __ISDIRTY) {
178 					orig->lines[sy + sub_win->begy - orig->begy]->flags
179 					    |= __ISDIRTY;
180 					sub_win->lines[sy]->flags
181 					    &= ~__ISDIRTY;
182 				}
183 			}
184 		}
185 	}
186 
187 	/* Check that cursor position on "win" is valid for "__virtscr" */
188 	if (win->cury + wbegy - begy < screen->__virtscr->maxy &&
189 	    win->cury + wbegy - begy >= 0 && win->cury < maxy - begy)
190 		screen->__virtscr->cury = win->cury + wbegy - begy;
191 	if (win->curx + wbegx - begx < screen->__virtscr->maxx &&
192 	    win->curx + wbegx - begx >= 0 && win->curx < maxx - begx)
193 		screen->__virtscr->curx = win->curx + wbegx - begx;
194 
195 	/* Copy the window flags from "win" to "__virtscr" */
196 	if (win->flags & __CLEAROK) {
197 		if (win->flags & __FULLWIN)
198 			screen->__virtscr->flags |= __CLEAROK;
199 		win->flags &= ~__CLEAROK;
200 	}
201 	screen->__virtscr->flags &= ~__LEAVEOK;
202 	screen->__virtscr->flags |= win->flags;
203 
204 	for (wy = begy, y_off = wbegy; wy < maxy &&
205 	    y_off < screen->__virtscr->maxy; wy++, y_off++) {
206 		wlp = win->lines[wy];
207 #ifdef DEBUG
208 		__CTRACE(__CTRACE_REFRESH,
209 		    "_wnoutrefresh: wy %d\tf %d\tl %d\tflags %x\n",
210 		    wy, *wlp->firstchp, *wlp->lastchp, wlp->flags);
211 #endif
212 		if ((wlp->flags & __ISDIRTY) == 0)
213 			continue;
214 		vlp = screen->__virtscr->lines[y_off];
215 
216 		if (*wlp->firstchp < maxx + win->ch_off &&
217 		    *wlp->lastchp >= win->ch_off) {
218 			/* Set start column */
219 			wx = begx;
220 			x_off = wbegx;
221 			if (*wlp->firstchp - win->ch_off > 0) {
222 				wx += *wlp->firstchp - win->ch_off;
223 				x_off += *wlp->firstchp - win->ch_off;
224 			}
225 			/* Set finish column */
226 			mx = maxx;
227 			if (mx > *wlp->lastchp - win->ch_off + 1)
228 				mx = *wlp->lastchp - win->ch_off + 1;
229 			if (x_off + (mx - wx) > __virtscr->maxx)
230 				mx -= (x_off + maxx) - __virtscr->maxx;
231 			/* Copy line from "win" to "__virtscr". */
232 			while (wx < mx) {
233 #ifdef DEBUG
234 				__CTRACE(__CTRACE_REFRESH,
235 				    "_wnoutrefresh: copy from %d, "
236 				    "%d to %d, %d\n",
237 				    wy, wx, y_off, x_off);
238 #endif
239 				/* Copy character */
240 				vlp->line[x_off].ch = wlp->line[wx].ch;
241 				/* Copy attributes  */
242 				vlp->line[x_off].attr = wlp->line[wx].attr;
243 				/* Check for nca conflict with colour */
244 				if ((vlp->line[x_off].attr & __COLOR) &&
245 				    (vlp->line[x_off].attr &
246 				    _cursesi_screen->nca))
247 					vlp->line[x_off].attr &= ~__COLOR;
248 #ifdef HAVE_WCHAR
249 				if (wlp->line[wx].ch
250 				    == (wchar_t)btowc((int) win->bch)) {
251 					vlp->line[x_off].ch = win->bch;
252 					SET_WCOL( vlp->line[x_off], 1 );
253 					if (_cursesi_copy_nsp(win->bnsp,
254 							      &vlp->line[x_off])
255 					    == ERR)
256 						return ERR;
257 				}
258 #endif /* HAVE_WCHAR */
259 				wx++;
260 				x_off++;
261 			}
262 
263 			/* Set flags on "__virtscr" and unset on "win". */
264 			if (wlp->flags & __ISPASTEOL)
265 				vlp->flags |= __ISPASTEOL;
266 			else
267 				vlp->flags &= ~__ISPASTEOL;
268 			if (wlp->flags & __ISDIRTY)
269 				vlp->flags |= __ISDIRTY;
270 
271 #ifdef DEBUG
272 			__CTRACE(__CTRACE_REFRESH,
273 			    "win: firstch = %d, lastch = %d\n",
274 			    *wlp->firstchp, *wlp->lastchp);
275 #endif
276 			/* Set change pointers on "__virtscr". */
277 			if (*vlp->firstchp >
278 			    *wlp->firstchp + wbegx - win->ch_off)
279 				*vlp->firstchp =
280 				    *wlp->firstchp + wbegx - win->ch_off;
281 			if (*vlp->lastchp <
282 			    *wlp->lastchp + wbegx - win->ch_off)
283 				*vlp->lastchp =
284 				    *wlp->lastchp + wbegx - win->ch_off;
285 #ifdef DEBUG
286 			__CTRACE(__CTRACE_REFRESH,
287 			    "__virtscr: firstch = %d, lastch = %d\n",
288 			    *vlp->firstchp, *vlp->lastchp);
289 #endif
290 			/*
291 			 * Unset change pointers only if a window, as a pad
292 			 * can be displayed again without any of the contents
293 			 * changing.
294 			 */
295 			if (!(win->flags & __ISPAD)) {
296 				/* Set change pointers on "win". */
297 				if (*wlp->firstchp >= win->ch_off)
298 					*wlp->firstchp = maxx + win->ch_off;
299 				if (*wlp->lastchp < maxx + win->ch_off)
300 					*wlp->lastchp = win->ch_off;
301 				if ((*wlp->lastchp < *wlp->firstchp) ||
302 				    (*wlp->firstchp >= maxx + win->ch_off) ||
303 				    (*wlp->lastchp <= win->ch_off)) {
304 #ifdef DEBUG
305 					__CTRACE(__CTRACE_REFRESH,
306 					    "_wnoutrefresh: "
307 					    "line %d notdirty\n", wy);
308 #endif
309 					wlp->flags &= ~__ISDIRTY;
310 				}
311 			}
312 		}
313 	}
314 	return OK;
315 }
316 
317 /*
318  * wrefresh --
319  *	Make the current screen look like "win" over the area covered by
320  *	win.
321  */
322 int
323 wrefresh(WINDOW *win)
324 {
325 	int retval;
326 
327 #ifdef DEBUG
328 	__CTRACE(__CTRACE_REFRESH, "wrefresh: win %p\n", win);
329 #endif
330 
331 	_cursesi_screen->curwin = (win == _cursesi_screen->curscr);
332 	if (!_cursesi_screen->curwin)
333 		retval = _cursesi_wnoutrefresh(_cursesi_screen, win, 0, 0,
334 		    win->begy, win->begx, win->maxy, win->maxx);
335 	else
336 		retval = OK;
337 	if (retval == OK) {
338 		retval = doupdate();
339 		if (!(win->flags & __LEAVEOK)) {
340 			win->cury = max(0, curscr->cury - win->begy);
341 			win->curx = max(0, curscr->curx - win->begx);
342 		}
343 	}
344 	_cursesi_screen->curwin = 0;
345 	return(retval);
346 }
347 
348  /*
349  * prefresh --
350  *	Make the current screen look like "pad" over the area coverd by
351  *	the specified area of pad.
352  */
353 int
354 prefresh(WINDOW *pad, int pbegy, int pbegx, int sbegy, int sbegx,
355 	int smaxy, int smaxx)
356 {
357 	int retval;
358 
359 #ifdef DEBUG
360 	__CTRACE(__CTRACE_REFRESH, "prefresh: pad %p, flags 0x%08x\n",
361 	    pad, pad->flags);
362 #endif
363 	/* Retain values in case pechochar() is called. */
364 	pad->pbegy = pbegy;
365 	pad->pbegx = pbegx;
366 	pad->sbegy = sbegy;
367 	pad->sbegx = sbegx;
368 	pad->smaxy = smaxy;
369 	pad->smaxx = smaxx;
370 
371 	/* Use pnoutrefresh() to avoid duplicating code here */
372 	retval = pnoutrefresh(pad, pbegy, pbegx, sbegy, sbegx, smaxy, smaxx);
373 	if (retval == OK) {
374 		retval = doupdate();
375 		if (!(pad->flags & __LEAVEOK)) {
376 			pad->cury = max(0, curscr->cury - pad->begy);
377 			pad->curx = max(0, curscr->curx - pad->begx);
378 		}
379 	}
380 	return(retval);
381 }
382 
383 /*
384  * doupdate --
385  *	Make the current screen look like the virtual window "__virtscr".
386  */
387 int
388 doupdate(void)
389 {
390 	WINDOW	*win;
391 	__LINE	*wlp;
392 	short	 wy;
393 	int	 dnum;
394 #ifdef HAVE_WCHAR
395 	__LDATA *lp;
396 	nschar_t *np;
397 	int x;
398 #endif /* HAVE_WCHAR */
399 
400 	/* Check if we need to restart ... */
401 	if (_cursesi_screen->endwin)
402 		__restartwin();
403 
404 	if (_cursesi_screen->curwin)
405 		win = curscr;
406 	else
407 		win = _cursesi_screen->__virtscr;
408 
409 	/* Initialize loop parameters. */
410 	_cursesi_screen->ly = curscr->cury;
411 	_cursesi_screen->lx = curscr->curx;
412 	wy = 0;
413 
414 	if (!_cursesi_screen->curwin) {
415 		for (wy = 0; wy < win->maxy; wy++) {
416 			wlp = win->lines[wy];
417 			if (wlp->flags & __ISDIRTY) {
418 #ifndef HAVE_WCHAR
419 				wlp->hash = __hash(wlp->line,
420 				    (size_t)(win->maxx * __LDATASIZE));
421 #else
422 				wlp->hash = 0;
423 				for ( x = 0; x < win->maxx; x++ ) {
424 					lp = &wlp->line[ x ];
425 					wlp->hash = __hash_more( &lp->ch,
426 						sizeof( wchar_t ), wlp->hash );
427 					wlp->hash = __hash_more( &lp->attr,
428 						sizeof( attr_t ), wlp->hash );
429 					np = lp->nsp;
430 					if (np) {
431 						while ( np ) {
432 							wlp->hash
433 							    = __hash_more(
434 								&np->ch,
435 								sizeof(wchar_t),
436 								wlp->hash );
437 							np = np->next;
438 						}
439 					}
440 				}
441 #endif /* HAVE_WCHAR */
442 			}
443 		}
444 	}
445 
446 	if ((win->flags & __CLEAROK) || (curscr->flags & __CLEAROK) ||
447 	    _cursesi_screen->curwin) {
448 		if (curscr->wattr & __COLOR)
449 			__unsetattr(0);
450 		tputs(__tc_cl, 0, __cputchar);
451 		_cursesi_screen->ly = 0;
452 		_cursesi_screen->lx = 0;
453 		if (!_cursesi_screen->curwin) {
454 			curscr->flags &= ~__CLEAROK;
455 			curscr->cury = 0;
456 			curscr->curx = 0;
457 			werase(curscr);
458 		}
459 		__touchwin(win);
460 		win->flags &= ~__CLEAROK;
461 	}
462 	if (!__CA) {
463 		if (win->curx != 0)
464 			__cputchar('\n');
465 		if (!_cursesi_screen->curwin)
466 			werase(curscr);
467 	}
468 #ifdef DEBUG
469 	__CTRACE(__CTRACE_REFRESH, "doupdate: (%p): curwin = %d\n", win,
470 	    _cursesi_screen->curwin);
471 	__CTRACE(__CTRACE_REFRESH, "doupdate: \tfirstch\tlastch\n");
472 #endif
473 
474 	if (!_cursesi_screen->curwin) {
475 		/*
476 		 * Invoke quickch() only if more than a quarter of the lines
477 		 * in the window are dirty.
478 		 */
479 		for (wy = 0, dnum = 0; wy < win->maxy; wy++)
480 			if (win->lines[wy]->flags & __ISDIRTY)
481 				dnum++;
482 		if (!__noqch && dnum > (int) win->maxy / 4)
483 			quickch();
484 	}
485 
486 #ifdef DEBUG
487 	{
488 		int	i, j;
489 
490 		__CTRACE(__CTRACE_REFRESH,
491 		    "#####################################\n");
492 		__CTRACE(__CTRACE_REFRESH,
493 		    "stdscr(%p)-curscr(%p)-__virtscr(%p)\n",
494 		    stdscr, curscr, _cursesi_screen->__virtscr);
495 		for (i = 0; i < curscr->maxy; i++) {
496 			__CTRACE(__CTRACE_REFRESH, "C: %d:", i);
497 			__CTRACE(__CTRACE_REFRESH, " 0x%x \n",
498 			    curscr->lines[i]->hash);
499 			for (j = 0; j < curscr->maxx; j++)
500 				__CTRACE(__CTRACE_REFRESH, "%c",
501 				    curscr->lines[i]->line[j].ch);
502 			__CTRACE(__CTRACE_REFRESH, "\n");
503 			__CTRACE(__CTRACE_REFRESH, " attr:");
504 			for (j = 0; j < curscr->maxx; j++)
505 				__CTRACE(__CTRACE_REFRESH, " %x",
506 				    curscr->lines[i]->line[j].attr);
507 			__CTRACE(__CTRACE_REFRESH, "\n");
508 			__CTRACE(__CTRACE_REFRESH, "W: %d:", i);
509 			__CTRACE(__CTRACE_REFRESH, " 0x%x \n",
510 			    win->lines[i]->hash);
511 			__CTRACE(__CTRACE_REFRESH, " 0x%x ",
512 			    win->lines[i]->flags);
513 			for (j = 0; j < win->maxx; j++)
514 				__CTRACE(__CTRACE_REFRESH, "%c",
515 				    win->lines[i]->line[j].ch);
516 			__CTRACE(__CTRACE_REFRESH, "\n");
517 			__CTRACE(__CTRACE_REFRESH, " attr:");
518 			for (j = 0; j < win->maxx; j++)
519 				__CTRACE(__CTRACE_REFRESH, " %x",
520 				    win->lines[i]->line[j].attr);
521 			__CTRACE(__CTRACE_REFRESH, "\n");
522 #ifdef HAVE_WCHAR
523 			__CTRACE(__CTRACE_REFRESH, " nsp:");
524 			for (j = 0; j < curscr->maxx; j++)
525 				__CTRACE(__CTRACE_REFRESH, " %p",
526 				    win->lines[i]->line[j].nsp);
527 			__CTRACE(__CTRACE_REFRESH, "\n");
528 			__CTRACE(__CTRACE_REFRESH, " bnsp:");
529 			for (j = 0; j < curscr->maxx; j++)
530 				__CTRACE(__CTRACE_REFRESH, " %p",
531 				    win->bnsp);
532 			__CTRACE(__CTRACE_REFRESH, "\n");
533 #endif /* HAVE_WCHAR */
534 		}
535 	}
536 #endif /* DEBUG */
537 
538 	for (wy = 0; wy < win->maxy; wy++) {
539 		wlp = win->lines[wy];
540 /* XXX: remove this debug */
541 #ifdef DEBUG
542 		__CTRACE(__CTRACE_REFRESH,
543 		    "doupdate: wy %d\tf: %d\tl:%d\tflags %x\n",
544 		    wy, *wlp->firstchp, *wlp->lastchp, wlp->flags);
545 #endif /* DEBUG */
546 		if (!_cursesi_screen->curwin)
547 			curscr->lines[wy]->hash = wlp->hash;
548 		if (wlp->flags & __ISDIRTY) {
549 #ifdef DEBUG
550 			__CTRACE(__CTRACE_REFRESH,
551 			    "doupdate: [ISDIRTY]wy:%d\tf:%d\tl:%d\n", wy,
552 			    *wlp->firstchp, *wlp->lastchp);
553 #endif /* DEBUG */
554 			if (makech(wy) == ERR)
555 				return (ERR);
556 			else {
557 				if (*wlp->firstchp >= 0)
558 					*wlp->firstchp = win->maxx;
559 				if (*wlp->lastchp < win->maxx)
560 					*wlp->lastchp = 0;
561 				if (*wlp->lastchp < *wlp->firstchp) {
562 #ifdef DEBUG
563 					__CTRACE(__CTRACE_REFRESH,
564 					    "doupdate: line %d notdirty\n", wy);
565 #endif /* DEBUG */
566 					wlp->flags &= ~__ISDIRTY;
567 				}
568 			}
569 
570 		}
571 #ifdef DEBUG
572 		__CTRACE(__CTRACE_REFRESH, "\t%d\t%d\n",
573 		    *wlp->firstchp, *wlp->lastchp);
574 #endif /* DEBUG */
575 	}
576 
577 #ifdef DEBUG
578 	__CTRACE(__CTRACE_REFRESH, "doupdate: ly=%d, lx=%d\n",
579 	    _cursesi_screen->ly, _cursesi_screen->lx);
580 #endif /* DEBUG */
581 
582 	if (_cursesi_screen->curwin)
583 		domvcur(_cursesi_screen->ly, _cursesi_screen->lx,
584 			win->cury, win->curx);
585 	else {
586 		if (win->flags & __LEAVEOK) {
587 			curscr->cury = _cursesi_screen->ly;
588 			curscr->curx = _cursesi_screen->lx;
589 		} else {
590 			domvcur(_cursesi_screen->ly, _cursesi_screen->lx,
591 				win->cury, win->curx);
592 			curscr->cury = win->cury;
593 			curscr->curx = win->curx;
594 		}
595 	}
596 
597 	/* Don't leave the screen with attributes set. */
598 	__unsetattr(0);
599 #ifdef DEBUG
600 #ifdef HAVE_WCHAR
601 	{
602 		int	i, j;
603 
604 		__CTRACE(__CTRACE_REFRESH,
605 		    "***********after*****************\n");
606 		__CTRACE(__CTRACE_REFRESH,
607 		    "stdscr(%p)-curscr(%p)-__virtscr(%p)\n",
608 		    stdscr, curscr, _cursesi_screen->__virtscr);
609 		for (i = 0; i < curscr->maxy; i++) {
610 			for (j = 0; j < curscr->maxx; j++)
611 				__CTRACE(__CTRACE_REFRESH,
612 				    "[%d,%d](%x,%x,%p)-(%x,%x,%p)\n",
613 				    i, j,
614 				    curscr->lines[i]->line[j].ch,
615 				    curscr->lines[i]->line[j].attr,
616 				    curscr->lines[i]->line[j].nsp,
617 				    _cursesi_screen->__virtscr->lines[i]->line[j].ch,
618 				    _cursesi_screen->__virtscr->lines[i]->line[j].attr,
619 				    _cursesi_screen->__virtscr->lines[i]->line[j].nsp);
620 		}
621 	}
622 #endif /* HAVE_WCHAR */
623 #endif /* DEBUG */
624 	return fflush(_cursesi_screen->outfd) == EOF ? ERR : OK;
625 }
626 
627 /*
628  * makech --
629  *	Make a change on the screen.
630  */
631 static int
632 makech(int wy)
633 {
634 	WINDOW	*win;
635 	static __LDATA blank;
636 	__LDATA *nsp, *csp, *cp, *cep;
637 	size_t	clsp, nlsp;	/* Last space in lines. */
638 	int	lch, wx;
639 	char	*ce;
640 	attr_t	lspc;		/* Last space colour */
641 	attr_t	off, on;
642 
643 #ifdef __GNUC__
644 	nlsp = lspc = 0;	/* XXX gcc -Wuninitialized */
645 #endif
646 	if (_cursesi_screen->curwin)
647 		win = curscr;
648 	else
649 		win = __virtscr;
650 #ifdef HAVE_WCHAR
651 	blank.ch = ( wchar_t )btowc(( int ) win->bch );
652 	blank.attr = 0;
653 	if (_cursesi_copy_nsp(win->bnsp, &blank) == ERR)
654 		return ERR;
655 	SET_WCOL( blank, 1 );
656 #endif /* HAVE_WCHAR */
657 #ifdef DEBUG
658 #if HAVE_WCHAR
659 	{
660 		int x;
661 		__LDATA *lp, *vlp;
662 
663 		__CTRACE(__CTRACE_REFRESH,
664 		    "[makech-before]wy=%d,curscr(%p)-__virtscr(%p)\n",
665 		    wy, curscr, __virtscr);
666 		for (x = 0; x < curscr->maxx; x++) {
667 			lp = &curscr->lines[wy]->line[x];
668 			vlp = &__virtscr->lines[wy]->line[x];
669 			__CTRACE(__CTRACE_REFRESH,
670 			    "[%d,%d](%x,%x,%x,%x,%p)-"
671 			    "(%x,%x,%x,%x,%p)\n",
672 			    wy, x, lp->ch, lp->attr,
673 			    win->bch, win->battr, lp->nsp,
674 			    vlp->ch, vlp->attr,
675 			    win->bch, win->battr, vlp->nsp);
676 		}
677 	}
678 #endif /* HAVE_WCHAR */
679 #endif /* DEBUG */
680 	/* Is the cursor still on the end of the last line? */
681 	if (wy > 0 && curscr->lines[wy - 1]->flags & __ISPASTEOL) {
682 		domvcur(_cursesi_screen->ly, _cursesi_screen->lx,
683 			_cursesi_screen->ly + 1, 0);
684 		_cursesi_screen->ly++;
685 		_cursesi_screen->lx = 0;
686 	}
687 	wx = *win->lines[wy]->firstchp;
688 	if (wx < 0)
689 		wx = 0;
690 	else
691 		if (wx >= win->maxx)
692 			return (OK);
693 	lch = *win->lines[wy]->lastchp;
694 	if (lch < 0)
695 		return (OK);
696 	else
697 		if (lch >= (int) win->maxx)
698 			lch = win->maxx - 1;
699 
700 	if (_cursesi_screen->curwin) {
701 		csp = &blank;
702 #ifdef DEBUG
703 		__CTRACE(__CTRACE_REFRESH, "makech: csp is blank\n");
704 #endif /* DEBUG */
705 	} else {
706 		csp = &curscr->lines[wy]->line[wx];
707 #ifdef DEBUG
708 		__CTRACE(__CTRACE_REFRESH,
709 		    "makech: csp is on curscr:(%d,%d)\n", wy, wx);
710 #endif /* DEBUG */
711 	}
712 
713 	nsp = &win->lines[wy]->line[wx];
714 #ifdef DEBUG
715 	if ( _cursesi_screen->curwin )
716 		__CTRACE(__CTRACE_REFRESH,
717 		    "makech: nsp is at curscr:(%d,%d)\n", wy, wx);
718 	else
719 		__CTRACE(__CTRACE_REFRESH,
720 		    "makech: nsp is at __virtscr:(%d,%d)\n", wy, wx);
721 #endif /* DEBUG */
722 	if (__tc_ce && !_cursesi_screen->curwin) {
723 		cp = &win->lines[wy]->line[win->maxx - 1];
724 		lspc = cp->attr & __COLOR;
725 #ifndef HAVE_WCHAR
726 		while (cp->ch == ' ' && cp->attr == lspc) /* XXX */
727 			if (cp-- <= win->lines[wy]->line)
728 				break;
729 #else
730 		while (cp->ch == ( wchar_t )btowc(( int )' ' )
731 				&& ( cp->attr & WA_ATTRIBUTES ) == lspc)
732 			if (cp-- <= win->lines[wy]->line)
733 				break;
734 #endif /* HAVE_WCHAR */
735 		if (win->lines[wy]->line > cp)
736 			nlsp = 0;
737 		else
738 			nlsp = cp - win->lines[wy]->line;
739 	}
740 	if (!_cursesi_screen->curwin)
741 		ce = __tc_ce;
742 	else
743 		ce = NULL;
744 
745 	while (wx <= lch) {
746 #ifdef DEBUG
747 		__CTRACE(__CTRACE_REFRESH, "makech: wx=%d,lch=%d\n", wx, lch);
748 #endif /* DEBUG */
749 #ifndef HAVE_WCHAR
750 		if (memcmp(nsp, csp, sizeof(__LDATA)) == 0) {
751 			if (wx <= lch) {
752 				while (wx <= lch &&
753 				    memcmp(nsp, csp, sizeof(__LDATA)) == 0) {
754 					nsp++;
755 					if (!_cursesi_screen->curwin)
756 						++csp;
757 					++wx;
758 				}
759 				continue;
760 			}
761 			break;
762 		}
763 #else
764 #ifdef DEBUG
765 		__CTRACE(__CTRACE_REFRESH, "makech: nsp=(%x,%x,%x,%x,%p)\n",
766 			nsp->ch, nsp->attr, win->bch, win->battr, nsp->nsp);
767 		__CTRACE(__CTRACE_REFRESH, "makech: csp=(%x,%x,%x,%x,%p)\n",
768 			csp->ch, csp->attr, win->bch, win->battr, csp->nsp);
769 #endif /* DEBUG */
770 		if (((nsp->attr & __WCWIDTH) != __WCWIDTH) &&
771 		    cellcmp(nsp, csp)) {
772 			if (wx <= lch) {
773 				while (wx <= lch && cellcmp( csp, nsp )) {
774 					nsp++;
775 					if (!_cursesi_screen->curwin)
776 						++csp;
777 					++wx;
778 				}
779 				continue;
780 			}
781 			break;
782 		}
783 #endif /* HAVE_WCHAR */
784 		domvcur(_cursesi_screen->ly, _cursesi_screen->lx, wy, wx);
785 
786 #ifdef DEBUG
787 		__CTRACE(__CTRACE_REFRESH, "makech: 1: wx = %d, ly= %d, "
788 		    "lx = %d, newy = %d, newx = %d\n",
789 		    wx, _cursesi_screen->ly, _cursesi_screen->lx, wy, wx);
790 #endif
791 		_cursesi_screen->ly = wy;
792 		_cursesi_screen->lx = wx;
793 #ifndef HAVE_WCHAR
794 		while (wx <= lch && memcmp(nsp, csp, sizeof(__LDATA)) != 0) {
795 			if (ce != NULL &&
796 			    wx >= nlsp && nsp->ch == ' ' && nsp->attr == lspc) {
797 #else
798 		while (!cellcmp(nsp, csp) && wx <= lch) {
799 			if (ce != NULL && wx >= nlsp
800 			   && nsp->ch == (wchar_t)btowc((int)' ') /* XXX */
801 			   && (nsp->attr & WA_ATTRIBUTES) == lspc) {
802 
803 #endif
804 				/* Check for clear to end-of-line. */
805 				cep = &curscr->lines[wy]->line[win->maxx - 1];
806 #ifndef HAVE_WCHAR
807 				while (cep->ch == ' ' && cep->attr == lspc) /* XXX */
808 #else
809 				while (cep->ch == (wchar_t)btowc((int)' ')
810 				       && (cep->attr & WA_ATTRIBUTES) == lspc)
811 #endif /* HAVE_WCHAR */
812 					if (cep-- <= csp)
813 						break;
814 				clsp = cep - curscr->lines[wy]->line -
815 				    win->begx * __LDATASIZE;
816 #ifdef DEBUG
817 				__CTRACE(__CTRACE_REFRESH,
818 				    "makech: clsp = %zu, nlsp = %zu\n",
819 				    clsp, nlsp);
820 #endif
821 				if (((clsp - nlsp >= strlen(__tc_ce) &&
822 				    clsp < win->maxx * __LDATASIZE) ||
823 				    wy == win->maxy - 1) &&
824 				    (!(lspc & __COLOR) ||
825 				    ((lspc & __COLOR) && __tc_ut))) {
826 					__unsetattr(0);
827 					if (__using_color &&
828 					    ((lspc & __COLOR) !=
829 					    (curscr->wattr & __COLOR)))
830 						__set_color(curscr, lspc &
831 						    __COLOR);
832 					tputs(__tc_ce, 0, __cputchar);
833 					_cursesi_screen->lx = wx + win->begx;
834 					while (wx++ <= clsp) {
835 						csp->attr = lspc;
836 #ifndef HAVE_WCHAR
837 						csp->ch = ' '; /* XXX */
838 #else
839 						csp->ch = (wchar_t)btowc((int)' ');
840 						SET_WCOL( *csp, 1 );
841 #endif /* HAVE_WCHAR */
842 						csp++;
843 					}
844 					return (OK);
845 				}
846 				ce = NULL;
847 			}
848 
849 #ifdef DEBUG
850 				__CTRACE(__CTRACE_REFRESH,
851 				    "makech: have attr %08x, need attr %08x\n",
852 				    curscr->wattr & WA_ATTRIBUTES,
853 				    nsp->attr & WA_ATTRIBUTES);
854 #endif
855 
856 			off = (~nsp->attr & curscr->wattr)
857 #ifndef HAVE_WCHAR
858 				 & __ATTRIBUTES
859 #else
860 				 & WA_ATTRIBUTES
861 #endif
862 				;
863 
864 			/*
865 			 * Unset attributes as appropriate.  Unset first
866 			 * so that the relevant attributes can be reset
867 			 * (because 'me' unsets 'mb', 'md', 'mh', 'mk',
868 			 * 'mp' and 'mr').  Check to see if we also turn off
869 			 * standout, attributes and colour.
870 			 */
871 			if (off & __TERMATTR && __tc_me != NULL) {
872 				tputs(__tc_me, 0, __cputchar);
873 				curscr->wattr &= __mask_me;
874 				off &= __mask_me;
875 			}
876 
877 			/*
878 			 * Exit underscore mode if appropriate.
879 			 * Check to see if we also turn off standout,
880 			 * attributes and colour.
881 			 */
882 			if (off & __UNDERSCORE && __tc_ue != NULL) {
883 				tputs(__tc_ue, 0, __cputchar);
884 				curscr->wattr &= __mask_ue;
885 				off &= __mask_ue;
886 			}
887 
888 			/*
889 			 * Exit standout mode as appropriate.
890 			 * Check to see if we also turn off underscore,
891 			 * attributes and colour.
892 			 * XXX
893 			 * Should use uc if so/se not available.
894 			 */
895 			if (off & __STANDOUT && __tc_se != NULL) {
896 				tputs(__tc_se, 0, __cputchar);
897 				curscr->wattr &= __mask_se;
898 				off &= __mask_se;
899 			}
900 
901 			if (off & __ALTCHARSET && __tc_ae != NULL) {
902 				tputs(__tc_ae, 0, __cputchar);
903 				curscr->wattr &= ~__ALTCHARSET;
904 			}
905 
906 			/* Set/change colour as appropriate. */
907 			if (__using_color)
908 				__set_color(curscr, nsp->attr & __COLOR);
909 
910 			on = (nsp->attr & ~curscr->wattr)
911 #ifndef HAVE_WCHAR
912 				 & __ATTRIBUTES
913 #else
914 				 & WA_ATTRIBUTES
915 #endif
916 				 ;
917 
918 			/*
919 			 * Enter standout mode if appropriate.
920 			 */
921 			if (on & __STANDOUT && __tc_so != NULL && __tc_se
922 			    != NULL) {
923 				tputs(__tc_so, 0, __cputchar);
924 				curscr->wattr |= __STANDOUT;
925 			}
926 
927 			/*
928 			 * Enter underscore mode if appropriate.
929 			 * XXX
930 			 * Should use uc if us/ue not available.
931 			 */
932 			if (on & __UNDERSCORE && __tc_us != NULL &&
933 			    __tc_ue != NULL) {
934 				tputs(__tc_us, 0, __cputchar);
935 				curscr->wattr |= __UNDERSCORE;
936 			}
937 
938 			/*
939 			 * Set other attributes as appropriate.
940 			 */
941 			if (__tc_me != NULL) {
942 				if (on & __BLINK && __tc_mb != NULL) {
943 					tputs(__tc_mb, 0, __cputchar);
944 					curscr->wattr |= __BLINK;
945 				}
946 				if (on & __BOLD && __tc_md != NULL) {
947 					tputs(__tc_md, 0, __cputchar);
948 					curscr->wattr |= __BOLD;
949 				}
950 				if (on & __DIM && __tc_mh != NULL) {
951 					tputs(__tc_mh, 0, __cputchar);
952 					curscr->wattr |= __DIM;
953 				}
954 				if (on & __BLANK && __tc_mk != NULL) {
955 					tputs(__tc_mk, 0, __cputchar);
956 					curscr->wattr |= __BLANK;
957 				}
958 				if (on & __PROTECT && __tc_mp != NULL) {
959 					tputs(__tc_mp, 0, __cputchar);
960 					curscr->wattr |= __PROTECT;
961 				}
962 				if (on & __REVERSE && __tc_mr != NULL) {
963 					tputs(__tc_mr, 0, __cputchar);
964 					curscr->wattr |= __REVERSE;
965 				}
966 #ifdef HAVE_WCHAR
967 				if (on & WA_TOP && __tc_Xt != NULL) {
968 					tputs(__tc_Xt, 0, __cputchar);
969 					curscr->wattr |= WA_TOP;
970 				}
971 				if (on & WA_LOW && __tc_Xo != NULL) {
972 					tputs(__tc_Xo, 0, __cputchar);
973 					curscr->wattr |= WA_LOW;
974 				}
975 				if (on & WA_LEFT && __tc_Xl != NULL) {
976 					tputs(__tc_Xl, 0, __cputchar);
977 					curscr->wattr |= WA_LEFT;
978 				}
979 				if (on & WA_RIGHT && __tc_Xl != NULL) {
980 					tputs(__tc_Xl, 0, __cputchar);
981 					curscr->wattr |= WA_RIGHT;
982 				}
983 				if (on & WA_HORIZONTAL && __tc_Xh != NULL) {
984 					tputs(__tc_Xh, 0, __cputchar);
985 					curscr->wattr |= WA_HORIZONTAL;
986 				}
987 				if (on & WA_VERTICAL && __tc_Xv != NULL) {
988 					tputs(__tc_Xv, 0, __cputchar);
989 					curscr->wattr |= WA_VERTICAL;
990 				}
991 #endif /* HAVE_WCHAR */
992 			}
993 
994 			/* Enter/exit altcharset mode as appropriate. */
995 			if (on & __ALTCHARSET && __tc_as != NULL &&
996 			    __tc_ae != NULL) {
997 				tputs(__tc_as, 0, __cputchar);
998 				curscr->wattr |= __ALTCHARSET;
999 			}
1000 
1001 			wx++;
1002 			if (wx >= win->maxx &&
1003 			    wy == win->maxy - 1 && !_cursesi_screen->curwin) {
1004 				if (win->flags & __SCROLLOK) {
1005 					if (win->flags & __ENDLINE)
1006 						__unsetattr(1);
1007 					if (!(win->flags & __SCROLLWIN)) {
1008 						if (!_cursesi_screen->curwin) {
1009 							csp->attr = nsp->attr;
1010 							csp->ch = nsp->ch;
1011 #ifdef HAVE_WCHAR
1012 							if (_cursesi_copy_nsp(nsp->nsp, csp) == ERR)
1013 								return ERR;
1014 #endif /* HAVE_WCHAR */
1015 						}
1016 #ifndef HAVE_WCHAR
1017 						__cputchar((int) nsp->ch);
1018 #else
1019 						if ( WCOL( *nsp ) > 0 ) {
1020 							__cputwchar((int)nsp->ch);
1021 #ifdef DEBUG
1022 							__CTRACE(__CTRACE_REFRESH,
1023 							    "makech: (%d,%d)putwchar(0x%x)\n",
1024 								wy, wx - 1,
1025 								nsp->ch );
1026 #endif /* DEBUG */
1027 							/*
1028 							 * Output non-spacing
1029 							 * characters for the
1030 							 * cell.
1031 							 */
1032 							__cursesi_putnsp(nsp->nsp,
1033 									 wy, wx);
1034 
1035 						}
1036 #endif /* HAVE_WCHAR */
1037 					}
1038 					if (wx < curscr->maxx) {
1039 						domvcur(_cursesi_screen->ly, wx,
1040 						    (int) (win->maxy - 1),
1041 						    (int) (win->maxx - 1));
1042 					}
1043 					_cursesi_screen->ly = win->maxy - 1;
1044 					_cursesi_screen->lx = win->maxx - 1;
1045 					return (OK);
1046 				}
1047 			}
1048 			if (wx < win->maxx || wy < win->maxy - 1 ||
1049 			    !(win->flags & __SCROLLWIN)) {
1050 				if (!_cursesi_screen->curwin) {
1051 					csp->attr = nsp->attr;
1052 					csp->ch = nsp->ch;
1053 #ifdef HAVE_WCHAR
1054 					if (_cursesi_copy_nsp(nsp->nsp,
1055 							      csp) == ERR)
1056 						return ERR;
1057 #endif /* HAVE_WCHAR */
1058 					csp++;
1059 				}
1060 #ifndef HAVE_WCHAR
1061 				__cputchar((int) nsp->ch);
1062 #ifdef DEBUG
1063 				__CTRACE(__CTRACE_REFRESH,
1064 				    "makech: putchar(%c)\n", nsp->ch & 0177);
1065 #endif
1066 #else
1067 				if (WCOL(*nsp) > 0) {
1068 					__cputwchar((int) nsp->ch);
1069 #ifdef DEBUG
1070 					__CTRACE(__CTRACE_REFRESH,
1071 					    "makech:(%d,%d) putwchar(%x)\n",
1072 					    wy, wx - 1, nsp->ch);
1073 					__cursesi_putnsp(nsp->nsp, wy, wx);
1074 #endif /* DEBUG */
1075 				}
1076 #endif /* HAVE_WCHAR */
1077 			}
1078 			if (__tc_uc && ((nsp->attr & __STANDOUT) ||
1079 			    (nsp->attr & __UNDERSCORE))) {
1080 				__cputchar('\b');
1081 				tputs(__tc_uc, 0, __cputchar);
1082 			}
1083 			nsp++;
1084 #ifdef DEBUG
1085 			__CTRACE(__CTRACE_REFRESH,
1086 			    "makech: 2: wx = %d, lx = %d\n",
1087 			    wx, _cursesi_screen->lx);
1088 #endif
1089 		}
1090 		if (_cursesi_screen->lx == wx)	/* If no change. */
1091 			break;
1092 		_cursesi_screen->lx = wx;
1093 		if (_cursesi_screen->lx >= COLS && __tc_am)
1094 			_cursesi_screen->lx = COLS - 1;
1095 		else
1096 			if (wx >= win->maxx) {
1097 				domvcur(_cursesi_screen->ly,
1098 					_cursesi_screen->lx,
1099 					_cursesi_screen->ly,
1100 					(int) (win->maxx - 1));
1101 				_cursesi_screen->lx = win->maxx - 1;
1102 			}
1103 #ifdef DEBUG
1104 		__CTRACE(__CTRACE_REFRESH, "makech: 3: wx = %d, lx = %d\n",
1105 		    wx, _cursesi_screen->lx);
1106 #endif
1107 	}
1108 #ifdef DEBUG
1109 #if HAVE_WCHAR
1110 	{
1111 		int x;
1112 		__LDATA *lp, *vlp;
1113 
1114 		__CTRACE(__CTRACE_REFRESH,
1115 		    "makech-after: curscr(%p)-__virtscr(%p)\n",
1116 		    curscr, __virtscr );
1117 		for (x = 0; x < curscr->maxx; x++) {
1118 			lp = &curscr->lines[wy]->line[x];
1119 			vlp = &__virtscr->lines[wy]->line[x];
1120 			__CTRACE(__CTRACE_REFRESH,
1121 			    "[%d,%d](%x,%x,%x,%x,%p)-"
1122 			    "(%x,%x,%x,%x,%p)\n",
1123 			    wy, x, lp->ch, lp->attr,
1124 			    win->bch, win->battr, lp->nsp,
1125 			    vlp->ch, vlp->attr,
1126 			    win->bch, win->battr, vlp->nsp);
1127 		}
1128 	}
1129 #endif /* HAVE_WCHAR */
1130 #endif /* DEBUG */
1131 
1132 	return (OK);
1133 }
1134 
1135 /*
1136  * domvcur --
1137  *	Do a mvcur, leaving attributes if necessary.
1138  */
1139 static void
1140 domvcur(oy, ox, ny, nx)
1141 	int	oy, ox, ny, nx;
1142 {
1143 #ifdef DEBUG
1144 	__CTRACE(__CTRACE_REFRESH, "domvcur: (%x,%d)=>(%d,%d)\n",
1145 	    oy, ox, ny, nx );
1146 #endif /* DEBUG */
1147 	__unsetattr(1);
1148 	if ( oy == ny && ox == nx )
1149 		return;
1150 	__mvcur(oy, ox, ny, nx, 1);
1151 }
1152 
1153 /*
1154  * Quickch() attempts to detect a pattern in the change of the window
1155  * in order to optimize the change, e.g., scroll n lines as opposed to
1156  * repainting the screen line by line.
1157  */
1158 
1159 static __LDATA buf[128];
1160 static  u_int last_hash;
1161 static  size_t last_hash_len;
1162 #define BLANKSIZE (sizeof(buf) / sizeof(buf[0]))
1163 
1164 static void
1165 quickch(void)
1166 {
1167 #define THRESH		(int) __virtscr->maxy / 4
1168 
1169 	__LINE *clp, *tmp1, *tmp2;
1170 	int	bsize, curs, curw, starts, startw, i, j;
1171 	int	n, target, cur_period, bot, top, sc_region;
1172 	u_int	blank_hash;
1173 	attr_t	bcolor;
1174 
1175 #ifdef __GNUC__
1176 	curs = curw = starts = startw = 0;	/* XXX gcc -Wuninitialized */
1177 #endif
1178 	/*
1179 	 * Find how many lines from the top of the screen are unchanged.
1180 	 */
1181 	for (top = 0; top < __virtscr->maxy; top++)
1182 #ifndef HAVE_WCHAR
1183 		if (__virtscr->lines[top]->flags & __ISDIRTY &&
1184 		    (__virtscr->lines[top]->hash != curscr->lines[top]->hash ||
1185 		    memcmp(__virtscr->lines[top]->line,
1186 		    curscr->lines[top]->line,
1187 		    (size_t) __virtscr->maxx * __LDATASIZE)
1188 		    != 0))
1189 			break;
1190 #else
1191 		if (__virtscr->lines[top]->flags & __ISDIRTY &&
1192 		    (__virtscr->lines[top]->hash != curscr->lines[top]->hash ||
1193 		    !linecmp(__virtscr->lines[top]->line,
1194 		    curscr->lines[top]->line,
1195 	(size_t) __virtscr->maxx )))
1196 			break;
1197 #endif /* HAVE_WCHAR */
1198 		else
1199 			__virtscr->lines[top]->flags &= ~__ISDIRTY;
1200 	/*
1201 	 * Find how many lines from bottom of screen are unchanged.
1202 	 */
1203 	for (bot = __virtscr->maxy - 1; bot >= 0; bot--)
1204 #ifndef HAVE_WCHAR
1205 		if (__virtscr->lines[bot]->flags & __ISDIRTY &&
1206 		    (__virtscr->lines[bot]->hash != curscr->lines[bot]->hash ||
1207 		    memcmp(__virtscr->lines[bot]->line,
1208 		    curscr->lines[bot]->line,
1209 		    (size_t) __virtscr->maxx * __LDATASIZE)
1210 		    != 0))
1211 			break;
1212 #else
1213 		if (__virtscr->lines[bot]->flags & __ISDIRTY &&
1214 		    (__virtscr->lines[bot]->hash != curscr->lines[bot]->hash ||
1215 		    !linecmp(__virtscr->lines[bot]->line,
1216 		    curscr->lines[bot]->line,
1217 		    (size_t) __virtscr->maxx )))
1218 			break;
1219 #endif /* HAVE_WCHAR */
1220 		else
1221 			__virtscr->lines[bot]->flags &= ~__ISDIRTY;
1222 
1223 	/*
1224 	 * Work round an xterm bug where inserting lines causes all the
1225 	 * inserted lines to be covered with the background colour we
1226 	 * set on the first line (even if we unset it for subsequent
1227 	 * lines).
1228 	 */
1229 	bcolor = __virtscr->lines[min(top,
1230 	    __virtscr->maxy - 1)]->line[0].attr & __COLOR;
1231 	for (i = top + 1, j = 0; i < bot; i++) {
1232 		if ((__virtscr->lines[i]->line[0].attr & __COLOR) != bcolor) {
1233 			bcolor = __virtscr->lines[i]->line[__virtscr->maxx].
1234 			    attr & __COLOR;
1235 			j = i - top;
1236 		} else
1237 			break;
1238 	}
1239 	top += j;
1240 
1241 #ifdef NO_JERKINESS
1242 	/*
1243 	 * If we have a bottom unchanged region return.  Scrolling the
1244 	 * bottom region up and then back down causes a screen jitter.
1245 	 * This will increase the number of characters sent to the screen
1246 	 * but it looks better.
1247 	 */
1248 	if (bot < __virtscr->maxy - 1)
1249 		return;
1250 #endif				/* NO_JERKINESS */
1251 
1252 	/*
1253 	 * Search for the largest block of text not changed.
1254 	 * Invariants of the loop:
1255 	 * - Startw is the index of the beginning of the examined block in
1256 	 *   __virtscr.
1257 	 * - Starts is the index of the beginning of the examined block in
1258 	 *   curscr.
1259 	 * - Curw is the index of one past the end of the exmined block in
1260 	 *   __virtscr.
1261 	 * - Curs is the index of one past the end of the exmined block in
1262 	 *   curscr.
1263 	 * - bsize is the current size of the examined block.
1264 	*/
1265 
1266 	for (bsize = bot - top; bsize >= THRESH; bsize--) {
1267 		for (startw = top; startw <= bot - bsize; startw++)
1268 			for (starts = top; starts <= bot - bsize;
1269 				starts++) {
1270 				for (curw = startw, curs = starts;
1271 				    curs < starts + bsize; curw++, curs++)
1272 					if (__virtscr->lines[curw]->hash !=
1273 					    curscr->lines[curs]->hash)
1274 						break;
1275 				if (curs != starts + bsize)
1276 					continue;
1277 				for (curw = startw, curs = starts;
1278 					curs < starts + bsize; curw++, curs++)
1279 #ifndef HAVE_WCHAR
1280 					if (memcmp(__virtscr->lines[curw]->line,
1281 					    curscr->lines[curs]->line,
1282 					    (size_t) __virtscr->maxx *
1283 					    __LDATASIZE) != 0)
1284 						break;
1285 #else
1286 					if (!linecmp(__virtscr->lines[curw]->line,
1287 					    curscr->lines[curs]->line,
1288 					    (size_t) __virtscr->maxx))
1289 						break;
1290 #endif /* HAVE_WCHAR */
1291 				if (curs == starts + bsize)
1292 					goto done;
1293 			}
1294 	}
1295 done:
1296 
1297 	/* Did not find anything */
1298 	if (bsize < THRESH)
1299 		return;
1300 
1301 #ifdef DEBUG
1302 	__CTRACE(__CTRACE_REFRESH, "quickch:bsize=%d, starts=%d, startw=%d, "
1303 	    "curw=%d, curs=%d, top=%d, bot=%d\n",
1304 	    bsize, starts, startw, curw, curs, top, bot);
1305 #endif
1306 
1307 	/*
1308 	 * Make sure that there is no overlap between the bottom and top
1309 	 * regions and the middle scrolled block.
1310 	 */
1311 	if (bot < curs)
1312 		bot = curs - 1;
1313 	if (top > starts)
1314 		top = starts;
1315 
1316 	n = startw - starts;
1317 
1318 #ifdef DEBUG
1319 	__CTRACE(__CTRACE_REFRESH, "#####################################\n");
1320 	for (i = 0; i < curscr->maxy; i++) {
1321 		__CTRACE(__CTRACE_REFRESH, "C: %d:", i);
1322 		__CTRACE(__CTRACE_REFRESH, " 0x%x \n", curscr->lines[i]->hash);
1323 		for (j = 0; j < curscr->maxx; j++)
1324 			__CTRACE(__CTRACE_REFRESH, "%c",
1325 			    curscr->lines[i]->line[j].ch);
1326 		__CTRACE(__CTRACE_REFRESH, "\n");
1327 		__CTRACE(__CTRACE_REFRESH, " attr:");
1328 		for (j = 0; j < curscr->maxx; j++)
1329 			__CTRACE(__CTRACE_REFRESH, " %x",
1330 			    curscr->lines[i]->line[j].attr);
1331 		__CTRACE(__CTRACE_REFRESH, "\n");
1332 		__CTRACE(__CTRACE_REFRESH, "W: %d:", i);
1333 		__CTRACE(__CTRACE_REFRESH, " 0x%x \n",
1334 		    __virtscr->lines[i]->hash);
1335 		__CTRACE(__CTRACE_REFRESH, " 0x%x ",
1336 		    __virtscr->lines[i]->flags);
1337 		for (j = 0; j < __virtscr->maxx; j++)
1338 			__CTRACE(__CTRACE_REFRESH, "%c",
1339 			    __virtscr->lines[i]->line[j].ch);
1340 		__CTRACE(__CTRACE_REFRESH, "\n");
1341 		__CTRACE(__CTRACE_REFRESH, " attr:");
1342 		for (j = 0; j < __virtscr->maxx; j++)
1343 			__CTRACE(__CTRACE_REFRESH, " %x",
1344 			    __virtscr->lines[i]->line[j].attr);
1345 		__CTRACE(__CTRACE_REFRESH, "\n");
1346 	}
1347 #endif
1348 
1349 #ifndef HAVE_WCHAR
1350 	if (buf[0].ch != ' ') {
1351 		for (i = 0; i < BLANKSIZE; i++) {
1352 			buf[i].ch = ' ';
1353 			buf[i].attr = 0;
1354 		}
1355 	}
1356 #else
1357 	if (buf[0].ch != ( wchar_t )btowc(( int ) curscr->bch )) {
1358 		for (i = 0; i < BLANKSIZE; i++) {
1359 			buf[i].ch = ( wchar_t )btowc(( int ) curscr->bch );
1360 			if (_cursesi_copy_nsp(curscr->bnsp, &buf[i]) == ERR)
1361 				return;
1362 			buf[i].attr = 0;
1363 			SET_WCOL( buf[ i ], 1 );
1364 		}
1365 	}
1366 #endif /* HAVE_WCHAR */
1367 
1368 	if (__virtscr->maxx != last_hash_len) {
1369 		blank_hash = 0;
1370 		for (i = __virtscr->maxx; i > BLANKSIZE; i -= BLANKSIZE) {
1371 			blank_hash = __hash_more(buf, sizeof(buf), blank_hash);
1372 		}
1373 		blank_hash = __hash_more((char *)(void *)buf,
1374 		    i * sizeof(buf[0]), blank_hash);
1375 		/* cache result in static data - screen width doesn't change often */
1376 		last_hash_len = __virtscr->maxx;
1377 		last_hash = blank_hash;
1378 	} else
1379 		blank_hash = last_hash;
1380 
1381 	/*
1382 	 * Perform the rotation to maintain the consistency of curscr.
1383 	 * This is hairy since we are doing an *in place* rotation.
1384 	 * Invariants of the loop:
1385 	 * - I is the index of the current line.
1386 	 * - Target is the index of the target of line i.
1387 	 * - Tmp1 points to current line (i).
1388 	 * - Tmp2 and points to target line (target);
1389 	 * - Cur_period is the index of the end of the current period.
1390 	 *   (see below).
1391 	 *
1392 	 * There are 2 major issues here that make this rotation non-trivial:
1393 	 * 1.  Scrolling in a scrolling region bounded by the top
1394 	 *     and bottom regions determined (whose size is sc_region).
1395 	 * 2.  As a result of the use of the mod function, there may be a
1396 	 *     period introduced, i.e., 2 maps to 4, 4 to 6, n-2 to 0, and
1397 	 *     0 to 2, which then causes all odd lines not to be rotated.
1398 	 *     To remedy this, an index of the end ( = beginning) of the
1399 	 *     current 'period' is kept, cur_period, and when it is reached,
1400 	 *     the next period is started from cur_period + 1 which is
1401 	 *     guaranteed not to have been reached since that would mean that
1402 	 *     all records would have been reached. (think about it...).
1403 	 *
1404 	 * Lines in the rotation can have 3 attributes which are marked on the
1405 	 * line so that curscr is consistent with the visual screen.
1406 	 * 1.  Not dirty -- lines inside the scrolled block, top region or
1407 	 *                  bottom region.
1408 	 * 2.  Blank lines -- lines in the differential of the scrolling
1409 	 *		      region adjacent to top and bot regions
1410 	 *                    depending on scrolling direction.
1411 	 * 3.  Dirty line -- all other lines are marked dirty.
1412 	 */
1413 	sc_region = bot - top + 1;
1414 	i = top;
1415 	tmp1 = curscr->lines[top];
1416 	cur_period = top;
1417 	for (j = top; j <= bot; j++) {
1418 		target = (i - top + n + sc_region) % sc_region + top;
1419 		tmp2 = curscr->lines[target];
1420 		curscr->lines[target] = tmp1;
1421 		/* Mark block as clean and blank out scrolled lines. */
1422 		clp = curscr->lines[target];
1423 #ifdef DEBUG
1424 		__CTRACE(__CTRACE_REFRESH,
1425 		    "quickch: n=%d startw=%d curw=%d i = %d target=%d ",
1426 		    n, startw, curw, i, target);
1427 #endif
1428 		if ((target >= startw && target < curw) || target < top
1429 		    || target > bot) {
1430 #ifdef DEBUG
1431 			__CTRACE(__CTRACE_REFRESH, " notdirty\n");
1432 #endif
1433 			__virtscr->lines[target]->flags &= ~__ISDIRTY;
1434 		} else
1435 			if ((n > 0 && target >= top && target < top + n) ||
1436 			    (n < 0 && target <= bot && target > bot + n)) {
1437 #ifndef HAVE_WCHAR
1438 				if (clp->hash != blank_hash ||
1439 				    memcmp(clp->line, clp->line + 1,
1440 				    (__virtscr->maxx - 1)
1441 				    * __LDATASIZE) ||
1442 				    memcmp(clp->line, buf, __LDATASIZE)) {
1443 #else
1444 				if (clp->hash != blank_hash
1445 				    || linecmp(clp->line, clp->line + 1,
1446 				    (unsigned int) (__virtscr->maxx - 1))
1447 				    || cellcmp(clp->line, buf)) {
1448 #endif /* HAVE_WCHAR */
1449 					for (i = __virtscr->maxx;
1450 					    i > BLANKSIZE;
1451 					    i -= BLANKSIZE) {
1452 						(void) memcpy(clp->line + i -
1453 						    BLANKSIZE, buf, sizeof(buf));
1454 					}
1455 					(void) memcpy(clp->line , buf, i *
1456 					    sizeof(buf[0]));
1457 #ifdef DEBUG
1458 					__CTRACE(__CTRACE_REFRESH,
1459 					    " blanked out: dirty\n");
1460 #endif
1461 					clp->hash = blank_hash;
1462 					__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
1463 				} else {
1464 #ifdef DEBUG
1465 					__CTRACE(__CTRACE_REFRESH,
1466 					    " -- blank line already: dirty\n");
1467 #endif
1468 					__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
1469 				}
1470 			} else {
1471 #ifdef DEBUG
1472 				__CTRACE(__CTRACE_REFRESH, " -- dirty\n");
1473 #endif
1474 				__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
1475 			}
1476 		if (target == cur_period) {
1477 			i = target + 1;
1478 			tmp1 = curscr->lines[i];
1479 			cur_period = i;
1480 		} else {
1481 			tmp1 = tmp2;
1482 			i = target;
1483 		}
1484 	}
1485 #ifdef DEBUG
1486 	__CTRACE(__CTRACE_REFRESH, "$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$\n");
1487 	for (i = 0; i < curscr->maxy; i++) {
1488 		__CTRACE(__CTRACE_REFRESH, "C: %d:", i);
1489 		for (j = 0; j < curscr->maxx; j++)
1490 			__CTRACE(__CTRACE_REFRESH, "%c",
1491 			    curscr->lines[i]->line[j].ch);
1492 		__CTRACE(__CTRACE_REFRESH, "\n");
1493 		__CTRACE(__CTRACE_REFRESH, "W: %d:", i);
1494 		for (j = 0; j < __virtscr->maxx; j++)
1495 			__CTRACE(__CTRACE_REFRESH, "%c",
1496 			    __virtscr->lines[i]->line[j].ch);
1497 		__CTRACE(__CTRACE_REFRESH, "\n");
1498 	}
1499 #endif
1500 	if (n != 0)
1501 		scrolln(starts, startw, curs, bot, top);
1502 }
1503 
1504 /*
1505  * scrolln --
1506  *	Scroll n lines, where n is starts - startw.
1507  */
1508 static void /* ARGSUSED */
1509 scrolln(starts, startw, curs, bot, top)
1510 	int	starts, startw, curs, bot, top;
1511 {
1512 	int	i, oy, ox, n;
1513 
1514 	oy = curscr->cury;
1515 	ox = curscr->curx;
1516 	n = starts - startw;
1517 
1518 	/*
1519 	 * XXX
1520 	 * The initial tests that set __noqch don't let us reach here unless
1521 	 * we have either cs + ho + SF/sf/SR/sr, or AL + DL.  SF/sf and SR/sr
1522 	 * scrolling can only shift the entire scrolling region, not just a
1523 	 * part of it, which means that the quickch() routine is going to be
1524 	 * sadly disappointed in us if we don't have cs as well.
1525 	 *
1526 	 * If cs, ho and SF/sf are set, can use the scrolling region.  Because
1527 	 * the cursor position after cs is undefined, we need ho which gives us
1528 	 * the ability to move to somewhere without knowledge of the current
1529 	 * location of the cursor.  Still call __mvcur() anyway, to update its
1530 	 * idea of where the cursor is.
1531 	 *
1532 	 * When the scrolling region has been set, the cursor has to be at the
1533 	 * last line of the region to make the scroll happen.
1534 	 *
1535 	 * Doing SF/SR or AL/DL appears faster on the screen than either sf/sr
1536 	 * or AL/DL, and, some terminals have AL/DL, sf/sr, and cs, but not
1537 	 * SF/SR.  So, if we're scrolling almost all of the screen, try and use
1538 	 * AL/DL, otherwise use the scrolling region.  The "almost all" is a
1539 	 * shameless hack for vi.
1540 	 */
1541 	if (n > 0) {
1542 		if (__tc_cs != NULL && __tc_ho != NULL && (__tc_SF != NULL ||
1543 		    ((__tc_AL == NULL || __tc_DL == NULL ||
1544 		    top > 3 || bot + 3 < __virtscr->maxy) &&
1545 		    __tc_sf != NULL))) {
1546 			tputs(__tscroll(__tc_cs, top, bot + 1), 0, __cputchar);
1547 			__mvcur(oy, ox, 0, 0, 1);
1548 			tputs(__tc_ho, 0, __cputchar);
1549 			__mvcur(0, 0, bot, 0, 1);
1550 			if (__tc_SF != NULL)
1551 				tputs(__tscroll(__tc_SF, n, 0), 0, __cputchar);
1552 			else
1553 				for (i = 0; i < n; i++)
1554 					tputs(__tc_sf, 0, __cputchar);
1555 			tputs(__tscroll(__tc_cs, 0, (int) __virtscr->maxy), 0,
1556 			    __cputchar);
1557 			__mvcur(bot, 0, 0, 0, 1);
1558 			tputs(__tc_ho, 0, __cputchar);
1559 			__mvcur(0, 0, oy, ox, 1);
1560 			return;
1561 		}
1562 
1563 		/* Scroll up the block. */
1564 		if (__tc_SF != NULL && top == 0) {
1565 			__mvcur(oy, ox, bot, 0, 1);
1566 			tputs(__tscroll(__tc_SF, n, 0), 0, __cputchar);
1567 		} else
1568 			if (__tc_DL != NULL) {
1569 				__mvcur(oy, ox, top, 0, 1);
1570 				tputs(__tscroll(__tc_DL, n, 0), 0, __cputchar);
1571 			} else
1572 				if (__tc_dl != NULL) {
1573 					__mvcur(oy, ox, top, 0, 1);
1574 					for (i = 0; i < n; i++)
1575 						tputs(__tc_dl, 0, __cputchar);
1576 				} else
1577 					if (__tc_sf != NULL && top == 0) {
1578 						__mvcur(oy, ox, bot, 0, 1);
1579 						for (i = 0; i < n; i++)
1580 							tputs(__tc_sf, 0,
1581 							    __cputchar);
1582 					} else
1583 						abort();
1584 
1585 		/* Push down the bottom region. */
1586 		__mvcur(top, 0, bot - n + 1, 0, 1);
1587 		if (__tc_AL != NULL)
1588 			tputs(__tscroll(__tc_AL, n, 0), 0, __cputchar);
1589 		else
1590 			if (__tc_al != NULL)
1591 				for (i = 0; i < n; i++)
1592 					tputs(__tc_al, 0, __cputchar);
1593 			else
1594 				abort();
1595 		__mvcur(bot - n + 1, 0, oy, ox, 1);
1596 	} else {
1597 		/*
1598 		 * !!!
1599 		 * n < 0
1600 		 *
1601 		 * If cs, ho and SR/sr are set, can use the scrolling region.
1602 		 * See the above comments for details.
1603 		 */
1604 		if (__tc_cs != NULL && __tc_ho != NULL && (__tc_SR != NULL ||
1605 		    ((__tc_AL == NULL || __tc_DL == NULL || top > 3 ||
1606 		    bot + 3 < __virtscr->maxy) && __tc_sr != NULL))) {
1607 			tputs(__tscroll(__tc_cs, top, bot + 1), 0, __cputchar);
1608 			__mvcur(oy, ox, 0, 0, 1);
1609 			tputs(__tc_ho, 0, __cputchar);
1610 			__mvcur(0, 0, top, 0, 1);
1611 
1612 			if (__tc_SR != NULL)
1613 				tputs(__tscroll(__tc_SR, -n, 0), 0, __cputchar);
1614 			else
1615 				for (i = n; i < 0; i++)
1616 					tputs(__tc_sr, 0, __cputchar);
1617 			tputs(__tscroll(__tc_cs, 0, (int) __virtscr->maxy), 0,
1618 			    __cputchar);
1619 			__mvcur(top, 0, 0, 0, 1);
1620 			tputs(__tc_ho, 0, __cputchar);
1621 			__mvcur(0, 0, oy, ox, 1);
1622 			return;
1623 		}
1624 
1625 		/* Preserve the bottom lines. */
1626 		__mvcur(oy, ox, bot + n + 1, 0, 1);
1627 		if (__tc_SR != NULL && bot == __virtscr->maxy)
1628 			tputs(__tscroll(__tc_SR, -n, 0), 0, __cputchar);
1629 		else
1630 			if (__tc_DL != NULL)
1631 				tputs(__tscroll(__tc_DL, -n, 0), 0, __cputchar);
1632 			else
1633 				if (__tc_dl != NULL)
1634 					for (i = n; i < 0; i++)
1635 						tputs(__tc_dl, 0, __cputchar);
1636 				else
1637 					if (__tc_sr != NULL &&
1638 					    bot == __virtscr->maxy)
1639 						for (i = n; i < 0; i++)
1640 							tputs(__tc_sr, 0,
1641 							    __cputchar);
1642 					else
1643 						abort();
1644 
1645 		/* Scroll the block down. */
1646 		__mvcur(bot + n + 1, 0, top, 0, 1);
1647 		if (__tc_AL != NULL)
1648 			tputs(__tscroll(__tc_AL, -n, 0), 0, __cputchar);
1649 		else
1650 			if (__tc_al != NULL)
1651 				for (i = n; i < 0; i++)
1652 					tputs(__tc_al, 0, __cputchar);
1653 			else
1654 				abort();
1655 		__mvcur(top, 0, oy, ox, 1);
1656 	}
1657 }
1658 
1659 /*
1660  * __unsetattr --
1661  *	Unset attributes on curscr.  Leave standout, attribute and colour
1662  *	modes if necessary (!ms).  Always leave altcharset (xterm at least
1663  *	ignores a cursor move if we don't).
1664  */
1665 void /* ARGSUSED */
1666 __unsetattr(int checkms)
1667 {
1668 	int	isms;
1669 
1670 	if (checkms)
1671 		if (!__tc_ms) {
1672 			isms = 1;
1673 		} else {
1674 			isms = 0;
1675 		}
1676 	else
1677 		isms = 1;
1678 #ifdef DEBUG
1679 	__CTRACE(__CTRACE_REFRESH,
1680 	    "__unsetattr: checkms = %d, ms = %s, wattr = %08x\n",
1681 	    checkms, __tc_ms ? "TRUE" : "FALSE", curscr->wattr);
1682 #endif
1683 
1684 	/*
1685 	 * Don't leave the screen in standout mode (check against ms).  Check
1686 	 * to see if we also turn off underscore, attributes and colour.
1687 	 */
1688 	if (curscr->wattr & __STANDOUT && isms) {
1689 		tputs(__tc_se, 0, __cputchar);
1690 		curscr->wattr &= __mask_se;
1691 	}
1692 	/*
1693 	 * Don't leave the screen in underscore mode (check against ms).
1694 	 * Check to see if we also turn off attributes.  Assume that we
1695 	 * also turn off colour.
1696 	 */
1697 	if (curscr->wattr & __UNDERSCORE && isms) {
1698 		tputs(__tc_ue, 0, __cputchar);
1699 		curscr->wattr &= __mask_ue;
1700 	}
1701 	/*
1702 	 * Don't leave the screen with attributes set (check against ms).
1703 	 * Assume that also turn off colour.
1704 	 */
1705 	if (curscr->wattr & __TERMATTR && isms) {
1706 		tputs(__tc_me, 0, __cputchar);
1707 		curscr->wattr &= __mask_me;
1708 	}
1709 	/* Don't leave the screen with altcharset set (don't check ms). */
1710 	if (curscr->wattr & __ALTCHARSET) {
1711 		tputs(__tc_ae, 0, __cputchar);
1712 		curscr->wattr &= ~__ALTCHARSET;
1713 	}
1714 	/* Don't leave the screen with colour set (check against ms). */
1715 	if (__using_color && isms)
1716 		__unset_color(curscr);
1717 }
1718 
1719 #ifdef HAVE_WCHAR
1720 /* compare two cells on screen, must have the same forground/background,
1721  * and the same sequence of non-spacing characters */
1722 int
1723 cellcmp( __LDATA *x, __LDATA *y )
1724 {
1725 	nschar_t *xnp = x->nsp, *ynp = y->nsp;
1726 	int ret = ( x->ch == y->ch ) & ( x->attr == y->attr );
1727 
1728 	if ( !ret )
1729 		return 0;
1730 	if ( !xnp && !ynp )
1731 		return 1;
1732 	if (( xnp && !ynp ) || ( !xnp && ynp ))
1733 		return 0;
1734 
1735 	while ( xnp && ynp ) {
1736 		if ( xnp->ch != ynp->ch )
1737 			return 0;
1738 		xnp = xnp->next;
1739 		ynp = ynp->next;
1740 	}
1741 	return ( !xnp && !ynp );
1742 }
1743 
1744 /* compare two line segments */
1745 int
1746 linecmp( __LDATA *xl, __LDATA *yl, size_t len )
1747 {
1748 	int i = 0;
1749 	__LDATA *xp = xl, *yp = yl;
1750 
1751 	for ( i = 0; i < len; i++, xp++, yp++ ) {
1752 		if ( !cellcmp( xp, yp ))
1753 			return 0;
1754 	}
1755 	return 1;
1756 }
1757 
1758 /*
1759  * Output the non-spacing characters associated with the given character
1760  * cell to the screen.
1761  */
1762 
1763 void
1764 __cursesi_putnsp(nschar_t *nsp, const int wy, const int wx)
1765 {
1766 	nschar_t *p;
1767 
1768 	/* this shuts up gcc warnings about wx and wy not being used */
1769 	if (wx > wy) {
1770 	}
1771 
1772 	p = nsp;
1773 	while (p != NULL) {
1774 		__cputwchar((int) p->ch);
1775 #ifdef DEBUG
1776 		__CTRACE(__CTRACE_REFRESH,
1777 		       "_cursesi_putnsp: (%d,%d) non-spacing putwchar(0x%x)\n",
1778 			 wy, wx - 1, p->ch);
1779 #endif
1780 		p = p->next;
1781 	}
1782 }
1783 
1784 #endif /* HAVE_WCHAR */
1785