xref: /netbsd-src/lib/libcurses/refresh.c (revision b8c616269f5ebf18ab2e35cb8099d683130a177c)
1 /*	$NetBSD: refresh.c,v 1.52 2003/01/27 21:11:12 jdc 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. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 #ifndef lint
38 #if 0
39 static char sccsid[] = "@(#)refresh.c	8.7 (Berkeley) 8/13/94";
40 #else
41 __RCSID("$NetBSD: refresh.c,v 1.52 2003/01/27 21:11:12 jdc Exp $");
42 #endif
43 #endif				/* not lint */
44 
45 #include <stdlib.h>
46 #include <string.h>
47 
48 #include "curses.h"
49 #include "curses_private.h"
50 
51 static void	domvcur __P((int, int, int, int));
52 static int	makech __P((int));
53 static void	quickch __P((void));
54 static void	scrolln __P((int, int, int, int, int));
55 
56 #ifndef _CURSES_USE_MACROS
57 
58 /*
59  * refresh --
60  *	Make the current screen look like "stdscr" over the area covered by
61  *	stdscr.
62  */
63 int
64 refresh(void)
65 {
66 	return wrefresh(stdscr);
67 }
68 
69 #endif
70 
71 /*
72  * wnoutrefresh --
73  *	Add the contents of "win" to the virtual window.
74  */
75 int
76 wnoutrefresh(WINDOW *win)
77 {
78 #ifdef DEBUG
79 	__CTRACE("wnoutrefresh: win %0.2o\n", win);
80 #endif
81 
82 	return _cursesi_wnoutrefresh(_cursesi_screen, win, 0, 0, win->begy,
83 	    win->begx, win->maxy, win->maxx);
84 }
85 
86 /*
87  * pnoutrefresh --
88  *	Add the contents of "pad" to the virtual window.
89  */
90 int
91 pnoutrefresh(WINDOW *pad, int pbegy, int pbegx, int sbegy, int sbegx,
92     int smaxy, int smaxx)
93 {
94 	int pmaxy, pmaxx;
95 
96 #ifdef DEBUG
97 	__CTRACE("pnoutrefresh: pad %0.2o, flags 0x%08x\n", pad, pad->flags);
98 	__CTRACE("pnoutrefresh: (%d, %d), (%d, %d), (%d, %d)\n", pbegy, pbegx,
99 	    sbegy, sbegx, smaxy, smaxx);
100 #endif
101 
102 	/* SUS says if these are negative, they should be treated as zero */
103 	if (pbegy < 0)
104 		pbegy = 0;
105 	if (pbegx < 0)
106 		pbegx = 0;
107 	if (sbegy < 0)
108 		sbegy = 0;
109 	if (sbegx < 0)
110 		sbegx = 0;
111 
112 	/* Calculate rectangle on pad - used bu _cursesi_wnoutrefresh */
113 	pmaxy = pbegy + smaxy - sbegy + 1;
114 	pmaxx = pbegx + smaxx - sbegx + 1;
115 
116 	/* Check rectangle fits in pad */
117 	if (pmaxy > pad->maxy - pad->begy)
118 		pmaxy = pad->maxy - pad->begy;
119 	if (pmaxx > pad->maxx - pad->begx)
120 		pmaxx = pad->maxx - pad->begx;
121 
122 	if (smaxy - sbegy < 0 || smaxx - sbegx < 0 )
123 		return ERR;
124 
125 	return _cursesi_wnoutrefresh(_cursesi_screen, pad,
126 	    pad->begy + pbegy, pad->begx + pbegx, pad->begy + sbegy,
127 	    pad->begx + sbegx, pmaxy, pmaxx);
128 }
129 
130 /*
131  * _cursesi_wnoutrefresh --
132  *      Does the grunt work for wnoutrefresh to the given screen.
133  *	Copies the part of the window given by the rectangle
134  *	(begy, begx) to (maxy, maxx) at screen position (wbegy, wbegx).
135  */
136 int
137 _cursesi_wnoutrefresh(SCREEN *screen, WINDOW *win, int begy, int begx,
138     int wbegy, int wbegx, int maxy, int maxx)
139 {
140 
141 	short	wy, wx, y_off, x_off;
142 	__LINE	*wlp, *vlp;
143 
144 #ifdef DEBUG
145 	__CTRACE("wnoutrefresh: win %0.2o, flags 0x%08x\n", win, win->flags);
146 	__CTRACE("wnoutrefresh: (%d, %d), (%d, %d), (%d, %d)\n", begy, begx,
147 		wbegy, wbegx, maxy, maxx);
148 #endif
149 
150 	if (screen->curwin)
151 		return(OK);
152 
153 	/* Check that cursor position on "win" is valid for "__virtscr" */
154 	if (win->cury + wbegy - begy < screen->__virtscr->maxy &&
155 	    win->cury + wbegy - begy >= 0 && win->cury < maxy - begy)
156 		screen->__virtscr->cury = win->cury + wbegy - begy;
157 	if (win->curx + wbegx - begx < screen->__virtscr->maxx &&
158 	    win->curx + wbegx - begx >= 0 && win->curx < maxx - begx)
159 		screen->__virtscr->curx = win->curx + wbegx - begx;
160 
161 	/* Copy the window flags from "win" to "__virtscr" */
162 	if (win->flags & __CLEAROK) {
163 		if (win->flags & __FULLWIN)
164 			screen->__virtscr->flags |= __CLEAROK;
165 		win->flags &= ~__CLEAROK;
166 	}
167 	screen->__virtscr->flags &= ~__LEAVEOK;
168 	screen->__virtscr->flags |= win->flags;
169 
170 	for (wy = begy, y_off = wbegy; wy < maxy &&
171 	    y_off < screen->__virtscr->maxy; wy++, y_off++) {
172  		wlp = win->lines[wy];
173 #ifdef DEBUG
174 		__CTRACE("wnoutrefresh: wy %d\tf: %d\tl:%d\tflags %x\n", wy,
175 		    *wlp->firstchp, *wlp->lastchp, wlp->flags);
176 #endif
177 		if ((wlp->flags & __ISDIRTY) == 0)
178 			continue;
179 		vlp = screen->__virtscr->lines[y_off];
180 
181 		if (*wlp->firstchp < maxx + win->ch_off &&
182 		    *wlp->lastchp >= win->ch_off) {
183 			/* Copy line from "win" to "__virtscr". */
184 			for (wx = begx + *wlp->firstchp - win->ch_off,
185 			    x_off = wbegx + *wlp->firstchp - win->ch_off;
186 			    wx <= *wlp->lastchp && wx < maxx &&
187 			    x_off < screen->__virtscr->maxx; wx++, x_off++) {
188 				vlp->line[x_off].attr = wlp->line[wx].attr;
189 				/* Copy attributes */
190 				if (wlp->line[wx].attr & __COLOR)
191 					vlp->line[x_off].attr |=
192 					    wlp->line[wx].battr & ~__COLOR;
193 				else
194 					vlp->line[x_off].attr |=
195 					    wlp->line[wx].battr;
196 				/* Check for nca conflict with colour */
197 				if ((vlp->line[x_off].attr & __COLOR) &&
198 				    (vlp->line[x_off].attr &
199 				    _cursesi_screen->nca))
200 					vlp->line[x_off].attr &= ~__COLOR;
201 				/* Copy character */
202 				if (wlp->line[wx].ch == ' ' &&
203 				    wlp->line[wx].bch != ' ')
204 					vlp->line[x_off].ch
205 					    = wlp->line[wx].bch;
206 				else
207 					vlp->line[x_off].ch
208 					    = wlp->line[wx].ch;
209 			}
210 
211 			/* Set flags on "__virtscr" and unset on "win". */
212 			if (wlp->flags & __ISPASTEOL)
213 				vlp->flags |= __ISPASTEOL;
214 			else
215 				vlp->flags &= ~__ISPASTEOL;
216 			if (wlp->flags & __ISDIRTY)
217 				vlp->flags |= __ISDIRTY;
218 
219 #ifdef DEBUG
220 			__CTRACE("win: firstch = %d, lastch = %d\n",
221 			    *wlp->firstchp, *wlp->lastchp);
222 #endif
223 			/* Set change pointers on "__virtscr". */
224 			if (*vlp->firstchp >
225 			    *wlp->firstchp + wbegx - win->ch_off)
226 				*vlp->firstchp =
227 				    *wlp->firstchp + wbegx - win->ch_off;
228 			if (*vlp->lastchp <
229 			    *wlp->lastchp + wbegx - win->ch_off)
230 				*vlp->lastchp =
231 				    *wlp->lastchp + wbegx - win->ch_off;
232 #ifdef DEBUG
233 			__CTRACE("__virtscr: firstch = %d, lastch = %d\n",
234 			    *vlp->firstchp, *vlp->lastchp);
235 #endif
236 			/*
237 			 * Unset change pointers only if a window, as a pad
238 			 * can be displayed again without any of the contents
239 			 * changing.
240 			 */
241 			if (!(win->flags & __ISPAD)) {
242 				/* Set change pointers on "win". */
243 				if (*wlp->firstchp >= win->ch_off)
244 					*wlp->firstchp = maxx + win->ch_off;
245 				if (*wlp->lastchp < maxx + win->ch_off)
246 					*wlp->lastchp = win->ch_off;
247 				if (*wlp->lastchp < *wlp->firstchp) {
248 #ifdef DEBUG
249 					__CTRACE("wnoutrefresh: line %d notdirty\n", wy);
250 #endif
251 					wlp->flags &= ~__ISDIRTY;
252 				}
253 			}
254 		}
255 	}
256 
257 	return (OK);
258 }
259 
260 /*
261  * wrefresh --
262  *	Make the current screen look like "win" over the area covered by
263  *	win.
264  */
265 int
266 wrefresh(WINDOW *win)
267 {
268 	int retval;
269 
270 #ifdef DEBUG
271 	__CTRACE("wrefresh: win %0.2o\n", win);
272 #endif
273 
274 	_cursesi_screen->curwin = (win == _cursesi_screen->curscr);
275 	if (!_cursesi_screen->curwin)
276 		retval = _cursesi_wnoutrefresh(_cursesi_screen, win, 0, 0,
277 		    win->begy, win->begx, win->maxy, win->maxx);
278 	else
279 		retval = OK;
280 	if (retval == OK) {
281 		retval = doupdate();
282 		if (!win->flags & __LEAVEOK) {
283 			win->cury = max(0, curscr->cury - win->begy);
284 			win->curx = max(0, curscr->curx - win->begx);
285 		}
286 	}
287 	_cursesi_screen->curwin = 0;
288 	return(retval);
289 }
290 
291  /*
292  * prefresh --
293  *	Make the current screen look like "pad" over the area coverd by
294  *	the specified area of pad.
295  */
296 int
297 prefresh(WINDOW *pad, int pbegy, int pbegx, int sbegy, int sbegx,
298     int smaxy, int smaxx)
299 {
300 	int retval;
301 
302 #ifdef DEBUG
303 	__CTRACE("prefresh: pad %0.2o, flags 0x%08x\n", pad, pad->flags);
304 #endif
305 
306 	/* Use pnoutrefresh() to avoid duplicating code here */
307 	retval = pnoutrefresh(pad, pbegy, pbegx, sbegy, sbegx, smaxy, smaxx);
308 	if (retval == OK) {
309 		retval = doupdate();
310 		if (!pad->flags & __LEAVEOK) {
311 			pad->cury = max(0, curscr->cury - pad->begy);
312 			pad->curx = max(0, curscr->curx - pad->begx);
313 		}
314 	}
315 	return(retval);
316 }
317 
318 /*
319  * doupdate --
320  *	Make the current screen look like the virtual window "__virtscr".
321  */
322 int
323 doupdate(void)
324 {
325 	WINDOW	*win;
326 	__LINE	*wlp;
327 	short	 wy;
328 	int	 dnum;
329 
330 	/* Check if we need to restart ... */
331 	if (_cursesi_screen->endwin)
332 		__restartwin();
333 
334 	if (_cursesi_screen->curwin)
335 		win = curscr;
336 	else
337 		win = _cursesi_screen->__virtscr;
338 
339 	/* Initialize loop parameters. */
340 	_cursesi_screen->ly = curscr->cury;
341 	_cursesi_screen->lx = curscr->curx;
342 	wy = 0;
343 
344 	if (!_cursesi_screen->curwin)
345 		for (wy = 0; wy < win->maxy; wy++) {
346 			wlp = win->lines[wy];
347 			if (wlp->flags & __ISDIRTY)
348 				wlp->hash = __hash((char *)(void *)wlp->line,
349 				    (size_t) (win->maxx * __LDATASIZE));
350 		}
351 
352 	if ((win->flags & __CLEAROK) || (curscr->flags & __CLEAROK) ||
353 	    _cursesi_screen->curwin) {
354 		if (curscr->wattr & __COLOR)
355 			__unsetattr(0);
356 		tputs(__tc_cl, 0, __cputchar);
357 		_cursesi_screen->ly = 0;
358 		_cursesi_screen->lx = 0;
359 		if (!_cursesi_screen->curwin) {
360 			curscr->flags &= ~__CLEAROK;
361 			curscr->cury = 0;
362 			curscr->curx = 0;
363 			werase(curscr);
364 		}
365 		__touchwin(win);
366 		win->flags &= ~__CLEAROK;
367 	}
368 	if (!__CA) {
369 		if (win->curx != 0)
370 			__cputchar('\n');
371 		if (!_cursesi_screen->curwin)
372 			werase(curscr);
373 	}
374 #ifdef DEBUG
375 	__CTRACE("doupdate: (%0.2o): curwin = %d\n", win,
376 		 _cursesi_screen->curwin);
377 	__CTRACE("doupdate: \tfirstch\tlastch\n");
378 #endif
379 
380 	if (!_cursesi_screen->curwin) {
381 		/*
382 		 * Invoke quickch() only if more than a quarter of the lines
383 		 * in the window are dirty.
384 		 */
385 		for (wy = 0, dnum = 0; wy < win->maxy; wy++)
386 			if (win->lines[wy]->flags & __ISDIRTY)
387 				dnum++;
388 		if (!__noqch && dnum > (int) win->maxy / 4)
389 			quickch();
390 	}
391 
392 #ifdef DEBUG
393 	{
394 		int	i, j;
395 
396 		__CTRACE("#####################################\n");
397 		for (i = 0; i < curscr->maxy; i++) {
398 			__CTRACE("C: %d:", i);
399 			__CTRACE(" 0x%x \n", curscr->lines[i]->hash);
400 			for (j = 0; j < curscr->maxx; j++)
401 				__CTRACE("%c", curscr->lines[i]->line[j].ch);
402 			__CTRACE("\n");
403 			__CTRACE(" attr:");
404 			for (j = 0; j < curscr->maxx; j++)
405 				__CTRACE(" %x",
406 					 curscr->lines[i]->line[j].attr);
407 			__CTRACE("\n");
408 			__CTRACE("W: %d:", i);
409 			__CTRACE(" 0x%x \n", win->lines[i]->hash);
410 			__CTRACE(" 0x%x ", win->lines[i]->flags);
411 			for (j = 0; j < win->maxx; j++)
412 				__CTRACE("%c", win->lines[i]->line[j].ch);
413 			__CTRACE("\n");
414 			__CTRACE(" attr:");
415 			for (j = 0; j < win->maxx; j++)
416 				__CTRACE(" %x",
417 				    win->lines[i]->line[j].attr);
418 			__CTRACE("\n");
419 		}
420 	}
421 #endif				/* DEBUG */
422 
423 	for (wy = 0; wy < win->maxy; wy++) {
424 		wlp = win->lines[wy];
425 /* XXX: remove this debug */
426 #ifdef DEBUG
427 		__CTRACE("doupdate: wy %d\tf: %d\tl:%d\tflags %x\n", wy,
428 		    *wlp->firstchp, *wlp->lastchp, wlp->flags);
429 #endif
430 		if (!_cursesi_screen->curwin)
431 			curscr->lines[wy]->hash = wlp->hash;
432 		if (wlp->flags & __ISDIRTY) {
433 			if (makech(wy) == ERR)
434 				return (ERR);
435 			else {
436 				if (*wlp->firstchp >= 0)
437 					*wlp->firstchp = win->maxx;
438 				if (*wlp->lastchp < win->maxx)
439 					*wlp->lastchp = 0;
440 				if (*wlp->lastchp < *wlp->firstchp) {
441 #ifdef DEBUG
442 					__CTRACE("doupdate: line %d notdirty\n", wy);
443 #endif
444 					wlp->flags &= ~__ISDIRTY;
445 				}
446 			}
447 
448 		}
449 #ifdef DEBUG
450 		__CTRACE("\t%d\t%d\n", *wlp->firstchp, *wlp->lastchp);
451 #endif
452 	}
453 
454 #ifdef DEBUG
455 	__CTRACE("doupdate: ly=%d, lx=%d\n", _cursesi_screen->ly,
456 		 _cursesi_screen->lx);
457 #endif
458 
459 	if (_cursesi_screen->curwin)
460 		domvcur(_cursesi_screen->ly, _cursesi_screen->lx,
461 			(int) win->cury, (int) win->curx);
462 	else {
463 		if (win->flags & __LEAVEOK) {
464 			curscr->cury = _cursesi_screen->ly;
465 			curscr->curx = _cursesi_screen->lx;
466 		} else {
467 			domvcur(_cursesi_screen->ly, _cursesi_screen->lx,
468 				win->cury, win->curx);
469 			curscr->cury = win->cury;
470 			curscr->curx = win->curx;
471 		}
472 	}
473 
474 	/* Don't leave the screen with attributes set. */
475 	__unsetattr(0);
476 	(void) fflush(_cursesi_screen->outfd);
477 	return (OK);
478 }
479 
480 /*
481  * makech --
482  *	Make a change on the screen.
483  */
484 static int
485 makech(wy)
486 	int	wy;
487 {
488 	WINDOW	*win;
489 	static __LDATA blank = {' ', 0, ' ', 0};
490 	__LDATA *nsp, *csp, *cp, *cep;
491 	int	clsp, nlsp;	/* Last space in lines. */
492 	int	lch, wx;
493 	char	*ce;
494 	attr_t	lspc;		/* Last space colour */
495 	attr_t	off, on;
496 
497 #ifdef __GNUC__
498 	nlsp = lspc = 0;	/* XXX gcc -Wuninitialized */
499 #endif
500 	if (_cursesi_screen->curwin)
501 		win = curscr;
502 	else
503 		win = __virtscr;
504 	/* Is the cursor still on the end of the last line? */
505 	if (wy > 0 && curscr->lines[wy - 1]->flags & __ISPASTEOL) {
506 		domvcur(_cursesi_screen->ly, _cursesi_screen->lx,
507 			_cursesi_screen->ly + 1, 0);
508 		_cursesi_screen->ly++;
509 		_cursesi_screen->lx = 0;
510 	}
511 	wx = *win->lines[wy]->firstchp;
512 	if (wx < 0)
513 		wx = 0;
514 	else
515 		if (wx >= win->maxx)
516 			return (OK);
517 	lch = *win->lines[wy]->lastchp;
518 	if (lch < 0)
519 		return (OK);
520 	else
521 		if (lch >= (int) win->maxx)
522 			lch = win->maxx - 1;
523 
524 	if (_cursesi_screen->curwin)
525 		csp = &blank;
526 	else
527 		csp = &curscr->lines[wy]->line[wx];
528 
529 	nsp = &win->lines[wy]->line[wx];
530 	if (__tc_ce && !_cursesi_screen->curwin) {
531 		cp = &win->lines[wy]->line[win->maxx - 1];
532 		lspc = cp->attr & __COLOR;
533 		while (cp->ch == ' ' && cp->attr == lspc)
534 			if (cp-- <= win->lines[wy]->line)
535 				break;
536 		nlsp = cp - win->lines[wy]->line;
537 		if (nlsp < 0)
538 			nlsp = 0;
539 	}
540 	if (!_cursesi_screen->curwin)
541 		ce = __tc_ce;
542 	else
543 		ce = NULL;
544 
545 	while (wx <= lch) {
546 		if (memcmp(nsp, csp, sizeof(__LDATA)) == 0) {
547 			if (wx <= lch) {
548 				while (wx <= lch &&
549 				    memcmp(nsp, csp, sizeof(__LDATA)) == 0) {
550 					nsp++;
551 					if (!_cursesi_screen->curwin)
552 						++csp;
553 					++wx;
554 				}
555 				continue;
556 			}
557 			break;
558 		}
559 		domvcur(_cursesi_screen->ly, _cursesi_screen->lx, wy, wx);
560 
561 #ifdef DEBUG
562 		__CTRACE("makech: 1: wx = %d, ly= %d, lx = %d, newy = %d, newx = %d\n",
563 		    wx, _cursesi_screen->ly, _cursesi_screen->lx, wy, wx);
564 #endif
565 		_cursesi_screen->ly = wy;
566 		_cursesi_screen->lx = wx;
567 		while (memcmp(nsp, csp, sizeof(__LDATA)) != 0 && wx <= lch) {
568 			if (ce != NULL &&
569 			    wx >= nlsp && nsp->ch == ' ' && nsp->attr == lspc) {
570 				/* Check for clear to end-of-line. */
571 				cep = &curscr->lines[wy]->line[win->maxx - 1];
572 				while (cep->ch == ' ' && cep->attr == lspc)
573 					if (cep-- <= csp)
574 						break;
575 				clsp = cep - curscr->lines[wy]->line -
576 				    win->begx * __LDATASIZE;
577 #ifdef DEBUG
578 				__CTRACE("makech: clsp = %d, nlsp = %d\n",
579 				    clsp, nlsp);
580 #endif
581 				if (((clsp - nlsp >= strlen(__tc_ce) &&
582 				    clsp < win->maxx * __LDATASIZE) ||
583 				    wy == win->maxy - 1) &&
584 				    (!(lspc & __COLOR) ||
585 				    ((lspc & __COLOR) && __tc_ut))) {
586 					__unsetattr(0);
587 					if (__using_color &&
588 					    ((lspc & __COLOR) !=
589 					    (curscr->wattr & __COLOR)))
590 						__set_color(curscr, lspc &
591 						    __COLOR);
592 					tputs(__tc_ce, 0, __cputchar);
593 					_cursesi_screen->lx = wx + win->begx;
594 					while (wx++ <= clsp) {
595 						csp->ch = ' ';
596 						csp->attr = lspc;
597 						csp++;
598 					}
599 					return (OK);
600 				}
601 				ce = NULL;
602 			}
603 
604 #ifdef DEBUG
605 				__CTRACE("makech: have attributes %08x, need attributes %08x\n", curscr->wattr, nsp->attr);
606 #endif
607 
608 			off = ~nsp->attr & curscr->wattr;
609 
610 			/*
611 			 * Unset attributes as appropriate.  Unset first
612 			 * so that the relevant attributes can be reset
613 			 * (because 'me' unsets 'mb', 'md', 'mh', 'mk',
614 			 * 'mp' and 'mr').  Check to see if we also turn off
615 			 * standout, attributes and colour.
616 			 */
617 			if (off & __TERMATTR && __tc_me != NULL) {
618 				tputs(__tc_me, 0, __cputchar);
619 				curscr->wattr &= __mask_me;
620 				off &= __mask_me;
621 			}
622 
623 			/*
624 			 * Exit underscore mode if appropriate.
625 			 * Check to see if we also turn off standout,
626 			 * attributes and colour.
627 			 */
628 			if (off & __UNDERSCORE && __tc_ue != NULL) {
629 				tputs(__tc_ue, 0, __cputchar);
630 				curscr->wattr &= __mask_ue;
631 				off &= __mask_ue;
632 			}
633 
634 			/*
635 			 * Exit standout mode as appropriate.
636 			 * Check to see if we also turn off underscore,
637 			 * attributes and colour.
638 			 * XXX
639 			 * Should use uc if so/se not available.
640 			 */
641 			if (off & __STANDOUT && __tc_se != NULL) {
642 				tputs(__tc_se, 0, __cputchar);
643 				curscr->wattr &= __mask_se;
644 				off &= __mask_se;
645 			}
646 
647 			if (off & __ALTCHARSET && __tc_ae != NULL) {
648 				tputs(__tc_ae, 0, __cputchar);
649 				curscr->wattr &= ~__ALTCHARSET;
650 			}
651 
652 			/* Set/change colour as appropriate. */
653 			if (__using_color)
654 				__set_color(curscr, nsp->attr & __COLOR);
655 
656 			on = nsp->attr & ~curscr->wattr;
657 
658 			/*
659 			 * Enter standout mode if appropriate.
660 			 */
661 			if (on & __STANDOUT && __tc_so != NULL && __tc_se
662 			    != NULL) {
663 				tputs(__tc_so, 0, __cputchar);
664 				curscr->wattr |= __STANDOUT;
665 			}
666 
667 			/*
668 			 * Enter underscore mode if appropriate.
669 			 * XXX
670 			 * Should use uc if us/ue not available.
671 			 */
672 			if (on & __UNDERSCORE && __tc_us != NULL &&
673 			    __tc_ue != NULL) {
674 				tputs(__tc_us, 0, __cputchar);
675 				curscr->wattr |= __UNDERSCORE;
676 			}
677 
678 			/*
679 			 * Set other attributes as appropriate.
680 			 */
681 			if (__tc_me != NULL) {
682 				if (on & __BLINK && __tc_mb != NULL) {
683 					tputs(__tc_mb, 0, __cputchar);
684 					curscr->wattr |= __BLINK;
685 				}
686 				if (on & __BOLD && __tc_md != NULL) {
687 					tputs(__tc_md, 0, __cputchar);
688 					curscr->wattr |= __BOLD;
689 				}
690 				if (on & __DIM && __tc_mh != NULL) {
691 					tputs(__tc_mh, 0, __cputchar);
692 					curscr->wattr |= __DIM;
693 				}
694 				if (on & __BLANK && __tc_mk != NULL) {
695 					tputs(__tc_mk, 0, __cputchar);
696 					curscr->wattr |= __BLANK;
697 				}
698 				if (on & __PROTECT && __tc_mp != NULL) {
699 					tputs(__tc_mp, 0, __cputchar);
700 					curscr->wattr |= __PROTECT;
701 				}
702 				if (on & __REVERSE && __tc_mr != NULL) {
703 					tputs(__tc_mr, 0, __cputchar);
704 					curscr->wattr |= __REVERSE;
705 				}
706 			}
707 
708 			/* Enter/exit altcharset mode as appropriate. */
709 			if (on & __ALTCHARSET && __tc_as != NULL &&
710 			    __tc_ae != NULL) {
711 				tputs(__tc_as, 0, __cputchar);
712 				curscr->wattr |= __ALTCHARSET;
713 			}
714 
715 			wx++;
716 			if (wx >= win->maxx &&
717 			    wy == win->maxy - 1 && !_cursesi_screen->curwin)
718 				if (win->flags & __SCROLLOK) {
719 					if (win->flags & __ENDLINE)
720 						__unsetattr(1);
721 					if (!(win->flags & __SCROLLWIN)) {
722 						if (!_cursesi_screen->curwin) {
723 							csp->attr = nsp->attr;
724 							__cputchar((int)
725 							    (csp->ch =
726 							    nsp->ch));
727 						} else
728 							__cputchar((int) nsp->ch);
729 					}
730 					if (wx < curscr->maxx) {
731 						domvcur(_cursesi_screen->ly, wx,
732 						    (int) (win->maxy - 1),
733 						    (int) (win->maxx - 1));
734 					}
735 					_cursesi_screen->ly = win->maxy - 1;
736 					_cursesi_screen->lx = win->maxx - 1;
737 					return (OK);
738 				}
739 			if (wx < win->maxx || wy < win->maxy - 1 ||
740 			    !(win->flags & __SCROLLWIN)) {
741 				if (!_cursesi_screen->curwin) {
742 					csp->attr = nsp->attr;
743 					__cputchar((int) (csp->ch = nsp->ch));
744 					csp++;
745 				} else
746 					__cputchar((int) nsp->ch);
747 			}
748 #ifdef DEBUG
749 			__CTRACE("makech: putchar(%c)\n", nsp->ch & 0177);
750 #endif
751 			if (__tc_uc && ((nsp->attr & __STANDOUT) ||
752 			    (nsp->attr & __UNDERSCORE))) {
753 				__cputchar('\b');
754 				tputs(__tc_uc, 0, __cputchar);
755 			}
756 			nsp++;
757 #ifdef DEBUG
758 			__CTRACE("makech: 2: wx = %d, lx = %d\n", wx, _cursesi_screen->lx);
759 #endif
760 		}
761 		if (_cursesi_screen->lx == wx)	/* If no change. */
762 			break;
763 		_cursesi_screen->lx = wx;
764 		if (_cursesi_screen->lx >= COLS && __tc_am)
765 			_cursesi_screen->lx = COLS - 1;
766 		else
767 			if (wx >= win->maxx) {
768 				domvcur(_cursesi_screen->ly,
769 					_cursesi_screen->lx,
770 					_cursesi_screen->ly,
771 					(int) (win->maxx - 1));
772 				_cursesi_screen->lx = win->maxx - 1;
773 			}
774 #ifdef DEBUG
775 		__CTRACE("makech: 3: wx = %d, lx = %d\n", wx,
776 			 _cursesi_screen->lx);
777 #endif
778 	}
779 
780 	return (OK);
781 }
782 
783 /*
784  * domvcur --
785  *	Do a mvcur, leaving attributes if necessary.
786  */
787 static void
788 domvcur(oy, ox, ny, nx)
789 	int	oy, ox, ny, nx;
790 {
791 	__unsetattr(1);
792 	__mvcur(oy, ox, ny, nx, 1);
793 }
794 
795 /*
796  * Quickch() attempts to detect a pattern in the change of the window
797  * in order to optimize the change, e.g., scroll n lines as opposed to
798  * repainting the screen line by line.
799  */
800 
801 static __LDATA buf[128];
802 static  u_int last_hash;
803 static  size_t last_hash_len;
804 #define BLANKSIZE (sizeof(buf) / sizeof(buf[0]))
805 
806 static void
807 quickch(void)
808 {
809 #define THRESH		(int) __virtscr->maxy / 4
810 
811 	__LINE *clp, *tmp1, *tmp2;
812 	int	bsize, curs, curw, starts, startw, i, j;
813 	int	n, target, cur_period, bot, top, sc_region;
814 	u_int	blank_hash;
815 	attr_t	bcolor;
816 
817 #ifdef __GNUC__
818 	curs = curw = starts = startw = 0;	/* XXX gcc -Wuninitialized */
819 #endif
820 	/*
821 	 * Find how many lines from the top of the screen are unchanged.
822 	 */
823 	for (top = 0; top < __virtscr->maxy; top++)
824 		if (__virtscr->lines[top]->flags & __ISDIRTY &&
825 		    (__virtscr->lines[top]->hash != curscr->lines[top]->hash ||
826 		     memcmp(__virtscr->lines[top]->line,
827 			  curscr->lines[top]->line,
828 			  (size_t) __virtscr->maxx * __LDATASIZE) != 0))
829 			break;
830 		else
831 			__virtscr->lines[top]->flags &= ~__ISDIRTY;
832 	/*
833 	 * Find how many lines from bottom of screen are unchanged.
834 	 */
835 	for (bot = __virtscr->maxy - 1; bot >= 0; bot--)
836 		if (__virtscr->lines[bot]->flags & __ISDIRTY &&
837 		    (__virtscr->lines[bot]->hash != curscr->lines[bot]->hash ||
838 		     memcmp(__virtscr->lines[bot]->line,
839 			  curscr->lines[bot]->line,
840 			  (size_t) __virtscr->maxx * __LDATASIZE) != 0))
841 			break;
842 		else
843 			__virtscr->lines[bot]->flags &= ~__ISDIRTY;
844 
845 	/*
846 	 * Work round an xterm bug where inserting lines causes all the
847 	 * inserted lines to be covered with the background colour we
848 	 * set on the first line (even if we unset it for subsequent
849 	 * lines).
850 	 */
851 	bcolor = __virtscr->lines[min(top,
852 	    __virtscr->maxy - 1)]->line[0].attr & __COLOR;
853 	for (i = top + 1, j = 0; i < bot; i++) {
854 		if ((__virtscr->lines[i]->line[0].attr & __COLOR) != bcolor) {
855 			bcolor = __virtscr->lines[i]->line[__virtscr->maxx].
856 			    attr & __COLOR;
857 			j = i - top;
858 		} else
859 			break;
860 	}
861 	top += j;
862 
863 #ifdef NO_JERKINESS
864 	/*
865 	 * If we have a bottom unchanged region return.  Scrolling the
866 	 * bottom region up and then back down causes a screen jitter.
867 	 * This will increase the number of characters sent to the screen
868 	 * but it looks better.
869 	 */
870 	if (bot < __virtscr->maxy - 1)
871 		return;
872 #endif				/* NO_JERKINESS */
873 
874 	/*
875 	 * Search for the largest block of text not changed.
876 	 * Invariants of the loop:
877 	 * - Startw is the index of the beginning of the examined block in
878 	 *   __virtscr.
879 	 * - Starts is the index of the beginning of the examined block in
880 	 *   curscr.
881 	 * - Curw is the index of one past the end of the exmined block in
882 	 *   __virtscr.
883 	 * - Curs is the index of one past the end of the exmined block in
884 	 *   curscr.
885 	 * - bsize is the current size of the examined block.
886 	*/
887 
888 	for (bsize = bot - top; bsize >= THRESH; bsize--) {
889 		for (startw = top; startw <= bot - bsize; startw++)
890 			for (starts = top; starts <= bot - bsize;
891 			    starts++) {
892 				for (curw = startw, curs = starts;
893 				    curs < starts + bsize; curw++, curs++)
894 					if (__virtscr->lines[curw]->hash !=
895 					    curscr->lines[curs]->hash)
896 						break;
897 				if (curs != starts + bsize)
898 					continue;
899 				for (curw = startw, curs = starts;
900 				    curs < starts + bsize; curw++, curs++)
901 					if (memcmp(__virtscr->lines[curw]->line,
902 					    curscr->lines[curs]->line,
903 					    (size_t) __virtscr->maxx *
904 					    __LDATASIZE) != 0)
905 						break;
906 				if (curs == starts + bsize)
907 					goto done;
908 			}
909 	}
910 done:
911 
912 	/* Did not find anything */
913 	if (bsize < THRESH)
914 		return;
915 
916 #ifdef DEBUG
917 	__CTRACE("quickch:bsize=%d,starts=%d,startw=%d,curw=%d,curs=%d,top=%d,bot=%d\n",
918 	    bsize, starts, startw, curw, curs, top, bot);
919 #endif
920 
921 	/*
922 	 * Make sure that there is no overlap between the bottom and top
923 	 * regions and the middle scrolled block.
924 	 */
925 	if (bot < curs)
926 		bot = curs - 1;
927 	if (top > starts)
928 		top = starts;
929 
930 	n = startw - starts;
931 
932 #ifdef DEBUG
933 	__CTRACE("#####################################\n");
934 	for (i = 0; i < curscr->maxy; i++) {
935 		__CTRACE("C: %d:", i);
936 		__CTRACE(" 0x%x \n", curscr->lines[i]->hash);
937 		for (j = 0; j < curscr->maxx; j++)
938 			__CTRACE("%c", curscr->lines[i]->line[j].ch);
939 		__CTRACE("\n");
940 		__CTRACE(" attr:");
941 		for (j = 0; j < curscr->maxx; j++)
942 			__CTRACE(" %x", curscr->lines[i]->line[j].attr);
943 		__CTRACE("\n");
944 		__CTRACE("W: %d:", i);
945 		__CTRACE(" 0x%x \n", __virtscr->lines[i]->hash);
946 		__CTRACE(" 0x%x ", __virtscr->lines[i]->flags);
947 		for (j = 0; j < __virtscr->maxx; j++)
948 			__CTRACE("%c", __virtscr->lines[i]->line[j].ch);
949 		__CTRACE("\n");
950 		__CTRACE(" attr:");
951 		for (j = 0; j < __virtscr->maxx; j++)
952 			__CTRACE(" %x", __virtscr->lines[i]->line[j].attr);
953 		__CTRACE("\n");
954 	}
955 #endif
956 
957 	if (buf[0].ch != ' ') {
958 		for (i = 0; i < BLANKSIZE; i++) {
959 			buf[i].ch = ' ';
960 			buf[i].bch = ' ';
961 			buf[i].attr = 0;
962 			buf[i].battr = 0;
963 		}
964 	}
965 
966 	if (__virtscr->maxx != last_hash_len) {
967 		blank_hash = 0;
968 		for (i = __virtscr->maxx; i > BLANKSIZE; i -= BLANKSIZE) {
969 			blank_hash = __hash_more((char *)(void *)buf, sizeof(buf),
970 			    blank_hash);
971 		}
972 		blank_hash = __hash_more((char *)(void *)buf,
973 		    i * sizeof(buf[0]), blank_hash);
974 		/* cache result in static data - screen width doesn't change often */
975 		last_hash_len = __virtscr->maxx;
976 		last_hash = blank_hash;
977 	} else
978 		blank_hash = last_hash;
979 
980 	/*
981 	 * Perform the rotation to maintain the consistency of curscr.
982 	 * This is hairy since we are doing an *in place* rotation.
983 	 * Invariants of the loop:
984 	 * - I is the index of the current line.
985 	 * - Target is the index of the target of line i.
986 	 * - Tmp1 points to current line (i).
987 	 * - Tmp2 and points to target line (target);
988 	 * - Cur_period is the index of the end of the current period.
989 	 *   (see below).
990 	 *
991 	 * There are 2 major issues here that make this rotation non-trivial:
992 	 * 1.  Scrolling in a scrolling region bounded by the top
993 	 *     and bottom regions determined (whose size is sc_region).
994 	 * 2.  As a result of the use of the mod function, there may be a
995 	 *     period introduced, i.e., 2 maps to 4, 4 to 6, n-2 to 0, and
996 	 *     0 to 2, which then causes all odd lines not to be rotated.
997 	 *     To remedy this, an index of the end ( = beginning) of the
998 	 *     current 'period' is kept, cur_period, and when it is reached,
999 	 *     the next period is started from cur_period + 1 which is
1000 	 *     guaranteed not to have been reached since that would mean that
1001 	 *     all records would have been reached. (think about it...).
1002 	 *
1003 	 * Lines in the rotation can have 3 attributes which are marked on the
1004 	 * line so that curscr is consistent with the visual screen.
1005 	 * 1.  Not dirty -- lines inside the scrolled block, top region or
1006 	 *                  bottom region.
1007 	 * 2.  Blank lines -- lines in the differential of the scrolling
1008 	 *		      region adjacent to top and bot regions
1009 	 *                    depending on scrolling direction.
1010 	 * 3.  Dirty line -- all other lines are marked dirty.
1011 	 */
1012 	sc_region = bot - top + 1;
1013 	i = top;
1014 	tmp1 = curscr->lines[top];
1015 	cur_period = top;
1016 	for (j = top; j <= bot; j++) {
1017 		target = (i - top + n + sc_region) % sc_region + top;
1018 		tmp2 = curscr->lines[target];
1019 		curscr->lines[target] = tmp1;
1020 		/* Mark block as clean and blank out scrolled lines. */
1021 		clp = curscr->lines[target];
1022 #ifdef DEBUG
1023 		__CTRACE("quickch: n=%d startw=%d curw=%d i = %d target=%d ",
1024 		    n, startw, curw, i, target);
1025 #endif
1026 		if ((target >= startw && target < curw) || target < top
1027 		    || target > bot) {
1028 #ifdef DEBUG
1029 			__CTRACE("-- notdirty\n");
1030 #endif
1031 			__virtscr->lines[target]->flags &= ~__ISDIRTY;
1032 		} else
1033 			if ((n > 0 && target >= top && target < top + n) ||
1034 			    (n < 0 && target <= bot && target > bot + n)) {
1035 				if (clp->hash != blank_hash || memcmp(clp->line,
1036 				    clp->line + 1, (__virtscr->maxx - 1) *
1037 				    __LDATASIZE) || memcmp(clp->line, buf,
1038 				    __LDATASIZE)) {
1039 					for (i = __virtscr->maxx; i > BLANKSIZE;
1040 					    i -= BLANKSIZE) {
1041 						(void)memcpy(clp->line + i -
1042 						    BLANKSIZE, buf, sizeof(buf));
1043 					}
1044 					(void)memcpy(clp->line , buf, i *
1045 					    sizeof(buf[0]));
1046 #ifdef DEBUG
1047 					__CTRACE("-- blanked out: dirty\n");
1048 #endif
1049 					clp->hash = blank_hash;
1050 					__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
1051 				} else {
1052 #ifdef DEBUG
1053 					__CTRACE(" -- blank line already: dirty\n");
1054 #endif
1055 					__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
1056 				}
1057 			} else {
1058 #ifdef DEBUG
1059 				__CTRACE(" -- dirty\n");
1060 #endif
1061 				__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
1062 			}
1063 		if (target == cur_period) {
1064 			i = target + 1;
1065 			tmp1 = curscr->lines[i];
1066 			cur_period = i;
1067 		} else {
1068 			tmp1 = tmp2;
1069 			i = target;
1070 		}
1071 	}
1072 #ifdef DEBUG
1073 	__CTRACE("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$\n");
1074 	for (i = 0; i < curscr->maxy; i++) {
1075 		__CTRACE("C: %d:", i);
1076 		for (j = 0; j < curscr->maxx; j++)
1077 			__CTRACE("%c", curscr->lines[i]->line[j].ch);
1078 		__CTRACE("\n");
1079 		__CTRACE("W: %d:", i);
1080 		for (j = 0; j < __virtscr->maxx; j++)
1081 			__CTRACE("%c", __virtscr->lines[i]->line[j].ch);
1082 		__CTRACE("\n");
1083 	}
1084 #endif
1085 	if (n != 0)
1086 		scrolln(starts, startw, curs, bot, top);
1087 }
1088 
1089 /*
1090  * scrolln --
1091  *	Scroll n lines, where n is starts - startw.
1092  */
1093 static void /* ARGSUSED */
1094 scrolln(starts, startw, curs, bot, top)
1095 	int	starts, startw, curs, bot, top;
1096 {
1097 	int	i, oy, ox, n;
1098 
1099 	oy = curscr->cury;
1100 	ox = curscr->curx;
1101 	n = starts - startw;
1102 
1103 	/*
1104 	 * XXX
1105 	 * The initial tests that set __noqch don't let us reach here unless
1106 	 * we have either cs + ho + SF/sf/SR/sr, or AL + DL.  SF/sf and SR/sr
1107 	 * scrolling can only shift the entire scrolling region, not just a
1108 	 * part of it, which means that the quickch() routine is going to be
1109 	 * sadly disappointed in us if we don't have cs as well.
1110 	 *
1111 	 * If cs, ho and SF/sf are set, can use the scrolling region.  Because
1112 	 * the cursor position after cs is undefined, we need ho which gives us
1113 	 * the ability to move to somewhere without knowledge of the current
1114 	 * location of the cursor.  Still call __mvcur() anyway, to update its
1115 	 * idea of where the cursor is.
1116 	 *
1117 	 * When the scrolling region has been set, the cursor has to be at the
1118 	 * last line of the region to make the scroll happen.
1119 	 *
1120 	 * Doing SF/SR or AL/DL appears faster on the screen than either sf/sr
1121 	 * or AL/DL, and, some terminals have AL/DL, sf/sr, and cs, but not
1122 	 * SF/SR.  So, if we're scrolling almost all of the screen, try and use
1123 	 * AL/DL, otherwise use the scrolling region.  The "almost all" is a
1124 	 * shameless hack for vi.
1125 	 */
1126 	if (n > 0) {
1127 		if (__tc_cs != NULL && __tc_ho != NULL && (__tc_SF != NULL ||
1128 		    ((__tc_AL == NULL || __tc_DL == NULL ||
1129 		    top > 3 || bot + 3 < __virtscr->maxy) &&
1130 		    __tc_sf != NULL))) {
1131 			tputs(__tscroll(__tc_cs, top, bot + 1), 0, __cputchar);
1132 			__mvcur(oy, ox, 0, 0, 1);
1133 			tputs(__tc_ho, 0, __cputchar);
1134 			__mvcur(0, 0, bot, 0, 1);
1135 			if (__tc_SF != NULL)
1136 				tputs(__tscroll(__tc_SF, n, 0), 0, __cputchar);
1137 			else
1138 				for (i = 0; i < n; i++)
1139 					tputs(__tc_sf, 0, __cputchar);
1140 			tputs(__tscroll(__tc_cs, 0, (int) __virtscr->maxy), 0,
1141 			    __cputchar);
1142 			__mvcur(bot, 0, 0, 0, 1);
1143 			tputs(__tc_ho, 0, __cputchar);
1144 			__mvcur(0, 0, oy, ox, 1);
1145 			return;
1146 		}
1147 
1148 		/* Scroll up the block. */
1149 		if (__tc_SF != NULL && top == 0) {
1150 			__mvcur(oy, ox, bot, 0, 1);
1151 			tputs(__tscroll(__tc_SF, n, 0), 0, __cputchar);
1152 		} else
1153 			if (__tc_DL != NULL) {
1154 				__mvcur(oy, ox, top, 0, 1);
1155 				tputs(__tscroll(__tc_DL, n, 0), 0, __cputchar);
1156 			} else
1157 				if (__tc_dl != NULL) {
1158 					__mvcur(oy, ox, top, 0, 1);
1159 					for (i = 0; i < n; i++)
1160 						tputs(__tc_dl, 0, __cputchar);
1161 				} else
1162 					if (__tc_sf != NULL && top == 0) {
1163 						__mvcur(oy, ox, bot, 0, 1);
1164 						for (i = 0; i < n; i++)
1165 							tputs(__tc_sf, 0,
1166 							    __cputchar);
1167 					} else
1168 						abort();
1169 
1170 		/* Push down the bottom region. */
1171 		__mvcur(top, 0, bot - n + 1, 0, 1);
1172 		if (__tc_AL != NULL)
1173 			tputs(__tscroll(__tc_AL, n, 0), 0, __cputchar);
1174 		else
1175 			if (__tc_al != NULL)
1176 				for (i = 0; i < n; i++)
1177 					tputs(__tc_al, 0, __cputchar);
1178 			else
1179 				abort();
1180 		__mvcur(bot - n + 1, 0, oy, ox, 1);
1181 	} else {
1182 		/*
1183 		 * !!!
1184 		 * n < 0
1185 		 *
1186 		 * If cs, ho and SR/sr are set, can use the scrolling region.
1187 		 * See the above comments for details.
1188 		 */
1189 		if (__tc_cs != NULL && __tc_ho != NULL && (__tc_SR != NULL ||
1190 		    ((__tc_AL == NULL || __tc_DL == NULL || top > 3 ||
1191 		    bot + 3 < __virtscr->maxy) && __tc_sr != NULL))) {
1192 			tputs(__tscroll(__tc_cs, top, bot + 1), 0, __cputchar);
1193 			__mvcur(oy, ox, 0, 0, 1);
1194 			tputs(__tc_ho, 0, __cputchar);
1195 			__mvcur(0, 0, top, 0, 1);
1196 
1197 			if (__tc_SR != NULL)
1198 				tputs(__tscroll(__tc_SR, -n, 0), 0, __cputchar);
1199 			else
1200 				for (i = n; i < 0; i++)
1201 					tputs(__tc_sr, 0, __cputchar);
1202 			tputs(__tscroll(__tc_cs, 0, (int) __virtscr->maxy), 0,
1203 			    __cputchar);
1204 			__mvcur(top, 0, 0, 0, 1);
1205 			tputs(__tc_ho, 0, __cputchar);
1206 			__mvcur(0, 0, oy, ox, 1);
1207 			return;
1208 		}
1209 
1210 		/* Preserve the bottom lines. */
1211 		__mvcur(oy, ox, bot + n + 1, 0, 1);
1212 		if (__tc_SR != NULL && bot == __virtscr->maxy)
1213 			tputs(__tscroll(__tc_SR, -n, 0), 0, __cputchar);
1214 		else
1215 			if (__tc_DL != NULL)
1216 				tputs(__tscroll(__tc_DL, -n, 0), 0, __cputchar);
1217 			else
1218 				if (__tc_dl != NULL)
1219 					for (i = n; i < 0; i++)
1220 						tputs(__tc_dl, 0, __cputchar);
1221 				else
1222 					if (__tc_sr != NULL &&
1223 					    bot == __virtscr->maxy)
1224 						for (i = n; i < 0; i++)
1225 							tputs(__tc_sr, 0,
1226 							    __cputchar);
1227 					else
1228 						abort();
1229 
1230 		/* Scroll the block down. */
1231 		__mvcur(bot + n + 1, 0, top, 0, 1);
1232 		if (__tc_AL != NULL)
1233 			tputs(__tscroll(__tc_AL, -n, 0), 0, __cputchar);
1234 		else
1235 			if (__tc_al != NULL)
1236 				for (i = n; i < 0; i++)
1237 					tputs(__tc_al, 0, __cputchar);
1238 			else
1239 				abort();
1240 		__mvcur(top, 0, oy, ox, 1);
1241 	}
1242 }
1243 
1244 /*
1245  * __unsetattr --
1246  *	Unset attributes on curscr.  Leave standout, attribute and colour
1247  *	modes if necessary (!ms).  Always leave altcharset (xterm at least
1248  *	ignores a cursor move if we don't).
1249  */
1250 void /* ARGSUSED */
1251 __unsetattr(int checkms)
1252 {
1253 	int	isms;
1254 
1255 	if (checkms)
1256 		if (!__tc_ms) {
1257 			isms = 1;
1258 		} else {
1259 			isms = 0;
1260 		}
1261 	else
1262 		isms = 1;
1263 #ifdef DEBUG
1264 	__CTRACE("__unsetattr: checkms = %d, ms = %s, wattr = %08x\n",
1265 	    checkms, __tc_ms ? "TRUE" : "FALSE", curscr->wattr);
1266 #endif
1267 
1268 	/*
1269          * Don't leave the screen in standout mode (check against ms).  Check
1270 	 * to see if we also turn off underscore, attributes and colour.
1271 	 */
1272 	if (curscr->wattr & __STANDOUT && isms) {
1273 		tputs(__tc_se, 0, __cputchar);
1274 		curscr->wattr &= __mask_se;
1275 	}
1276 	/*
1277 	 * Don't leave the screen in underscore mode (check against ms).
1278 	 * Check to see if we also turn off attributes.  Assume that we
1279 	 * also turn off colour.
1280 	 */
1281 	if (curscr->wattr & __UNDERSCORE && isms) {
1282 		tputs(__tc_ue, 0, __cputchar);
1283 		curscr->wattr &= __mask_ue;
1284 	}
1285 	/*
1286 	 * Don't leave the screen with attributes set (check against ms).
1287 	 * Assume that also turn off colour.
1288 	 */
1289 	if (curscr->wattr & __TERMATTR && isms) {
1290 		tputs(__tc_me, 0, __cputchar);
1291 		curscr->wattr &= __mask_me;
1292 	}
1293 	/* Don't leave the screen with altcharset set (don't check ms). */
1294 	if (curscr->wattr & __ALTCHARSET) {
1295 		tputs(__tc_ae, 0, __cputchar);
1296 		curscr->wattr &= ~__ALTCHARSET;
1297 	}
1298 	/* Don't leave the screen with colour set (check against ms). */
1299 	if (__using_color && isms)
1300 		__unset_color(curscr);
1301 }
1302