xref: /netbsd-src/lib/libcurses/refresh.c (revision d710132b4b8ce7f7cccaaf660cb16aa16b4077a0)
1 /*	$NetBSD: refresh.c,v 1.54 2003/03/29 21:43:22 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 1.54 2003/03/29 21:43:22 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 %p\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 %p, 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 by _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 	WINDOW	*sub_win;
144 
145 #ifdef DEBUG
146 	__CTRACE("wnoutrefresh: win %p, flags 0x%08x\n", win, win->flags);
147 	__CTRACE("wnoutrefresh: (%d, %d), (%d, %d), (%d, %d)\n", begy, begx,
148 		wbegy, wbegx, maxy, maxx);
149 #endif
150 
151 	if (screen->curwin)
152 		return(OK);
153 
154 	/* Check that cursor position on "win" is valid for "__virtscr" */
155 	if (win->cury + wbegy - begy < screen->__virtscr->maxy &&
156 	    win->cury + wbegy - begy >= 0 && win->cury < maxy - begy)
157 		screen->__virtscr->cury = win->cury + wbegy - begy;
158 	if (win->curx + wbegx - begx < screen->__virtscr->maxx &&
159 	    win->curx + wbegx - begx >= 0 && win->curx < maxx - begx)
160 		screen->__virtscr->curx = win->curx + wbegx - begx;
161 
162 	/* Copy the window flags from "win" to "__virtscr" */
163 	if (win->flags & __CLEAROK) {
164 		if (win->flags & __FULLWIN)
165 			screen->__virtscr->flags |= __CLEAROK;
166 		win->flags &= ~__CLEAROK;
167 	}
168 	screen->__virtscr->flags &= ~__LEAVEOK;
169 	screen->__virtscr->flags |= win->flags;
170 
171 	for (wy = begy, y_off = wbegy; wy < maxy &&
172 	    y_off < screen->__virtscr->maxy; wy++, y_off++) {
173  		wlp = win->lines[wy];
174 #ifdef DEBUG
175 		__CTRACE("wnoutrefresh: wy %d\tf: %d\tl:%d\tflags %x\n", wy,
176 		    *wlp->firstchp, *wlp->lastchp, wlp->flags);
177 #endif
178 		if ((wlp->flags & __ISDIRTY) == 0)
179 			continue;
180 		vlp = screen->__virtscr->lines[y_off];
181 
182 		if (*wlp->firstchp < maxx + win->ch_off &&
183 		    *wlp->lastchp >= win->ch_off) {
184 			/* Copy line from "win" to "__virtscr". */
185 			for (wx = begx + *wlp->firstchp - win->ch_off,
186 			    x_off = wbegx + *wlp->firstchp - win->ch_off;
187 			    wx <= *wlp->lastchp && wx < maxx &&
188 			    x_off < screen->__virtscr->maxx; wx++, x_off++) {
189 				vlp->line[x_off].attr = wlp->line[wx].attr;
190 				/* Copy attributes */
191 				if (wlp->line[wx].attr & __COLOR)
192 					vlp->line[x_off].attr |=
193 					    wlp->line[wx].battr & ~__COLOR;
194 				else
195 					vlp->line[x_off].attr |=
196 					    wlp->line[wx].battr;
197 				/* Check for nca conflict with colour */
198 				if ((vlp->line[x_off].attr & __COLOR) &&
199 				    (vlp->line[x_off].attr &
200 				    _cursesi_screen->nca))
201 					vlp->line[x_off].attr &= ~__COLOR;
202 				/* Copy character */
203 				if (wlp->line[wx].ch == ' ' &&
204 				    wlp->line[wx].bch != ' ')
205 					vlp->line[x_off].ch
206 					    = wlp->line[wx].bch;
207 				else
208 					vlp->line[x_off].ch
209 					    = wlp->line[wx].ch;
210 			}
211 
212 			/* Set flags on "__virtscr" and unset on "win". */
213 			if (wlp->flags & __ISPASTEOL)
214 				vlp->flags |= __ISPASTEOL;
215 			else
216 				vlp->flags &= ~__ISPASTEOL;
217 			if (wlp->flags & __ISDIRTY)
218 				vlp->flags |= __ISDIRTY;
219 
220 #ifdef DEBUG
221 			__CTRACE("win: firstch = %d, lastch = %d\n",
222 			    *wlp->firstchp, *wlp->lastchp);
223 #endif
224 			/* Set change pointers on "__virtscr". */
225 			if (*vlp->firstchp >
226 			    *wlp->firstchp + wbegx - win->ch_off)
227 				*vlp->firstchp =
228 				    *wlp->firstchp + wbegx - win->ch_off;
229 			if (*vlp->lastchp <
230 			    *wlp->lastchp + wbegx - win->ch_off)
231 				*vlp->lastchp =
232 				    *wlp->lastchp + wbegx - win->ch_off;
233 #ifdef DEBUG
234 			__CTRACE("__virtscr: firstch = %d, lastch = %d\n",
235 			    *vlp->firstchp, *vlp->lastchp);
236 #endif
237 			/*
238 			 * Unset change pointers only if a window, as a pad
239 			 * can be displayed again without any of the contents
240 			 * changing.
241 			 */
242 			if (!(win->flags & __ISPAD)) {
243 				/* Set change pointers on "win". */
244 				if (*wlp->firstchp >= win->ch_off)
245 					*wlp->firstchp = maxx + win->ch_off;
246 				if (*wlp->lastchp < maxx + win->ch_off)
247 					*wlp->lastchp = win->ch_off;
248 				if (*wlp->lastchp < *wlp->firstchp) {
249 #ifdef DEBUG
250 					__CTRACE("wnoutrefresh: line %d notdirty\n", wy);
251 #endif
252 					wlp->flags &= ~__ISDIRTY;
253 				}
254 			}
255 		}
256 	}
257 
258 	/* Recurse through any sub-windows */
259 	if ((sub_win = win->nextp) != win && sub_win != win->orig) {
260 #ifdef DEBUG
261 		__CTRACE("wnoutrefresh: win %o, sub_win %o\n", win, sub_win);
262 #endif
263 		return _cursesi_wnoutrefresh(screen, sub_win, 0, 0,
264 		    sub_win->begy, sub_win->begx,
265 		    sub_win->maxy, sub_win->maxx);
266 	} else
267 		return OK;
268 }
269 
270 /*
271  * wrefresh --
272  *	Make the current screen look like "win" over the area covered by
273  *	win.
274  */
275 int
276 wrefresh(WINDOW *win)
277 {
278 	int retval;
279 
280 #ifdef DEBUG
281 	__CTRACE("wrefresh: win %p\n", win);
282 #endif
283 
284 	_cursesi_screen->curwin = (win == _cursesi_screen->curscr);
285 	if (!_cursesi_screen->curwin)
286 		retval = _cursesi_wnoutrefresh(_cursesi_screen, win, 0, 0,
287 		    win->begy, win->begx, win->maxy, win->maxx);
288 	else
289 		retval = OK;
290 	if (retval == OK) {
291 		retval = doupdate();
292 		if (!win->flags & __LEAVEOK) {
293 			win->cury = max(0, curscr->cury - win->begy);
294 			win->curx = max(0, curscr->curx - win->begx);
295 		}
296 	}
297 	_cursesi_screen->curwin = 0;
298 	return(retval);
299 }
300 
301  /*
302  * prefresh --
303  *	Make the current screen look like "pad" over the area coverd by
304  *	the specified area of pad.
305  */
306 int
307 prefresh(WINDOW *pad, int pbegy, int pbegx, int sbegy, int sbegx,
308     int smaxy, int smaxx)
309 {
310 	int retval;
311 
312 #ifdef DEBUG
313 	__CTRACE("prefresh: pad %p, flags 0x%08x\n", pad, pad->flags);
314 #endif
315 
316 	/* Use pnoutrefresh() to avoid duplicating code here */
317 	retval = pnoutrefresh(pad, pbegy, pbegx, sbegy, sbegx, smaxy, smaxx);
318 	if (retval == OK) {
319 		retval = doupdate();
320 		if (!pad->flags & __LEAVEOK) {
321 			pad->cury = max(0, curscr->cury - pad->begy);
322 			pad->curx = max(0, curscr->curx - pad->begx);
323 		}
324 	}
325 	return(retval);
326 }
327 
328 /*
329  * doupdate --
330  *	Make the current screen look like the virtual window "__virtscr".
331  */
332 int
333 doupdate(void)
334 {
335 	WINDOW	*win;
336 	__LINE	*wlp;
337 	short	 wy;
338 	int	 dnum;
339 
340 	/* Check if we need to restart ... */
341 	if (_cursesi_screen->endwin)
342 		__restartwin();
343 
344 	if (_cursesi_screen->curwin)
345 		win = curscr;
346 	else
347 		win = _cursesi_screen->__virtscr;
348 
349 	/* Initialize loop parameters. */
350 	_cursesi_screen->ly = curscr->cury;
351 	_cursesi_screen->lx = curscr->curx;
352 	wy = 0;
353 
354 	if (!_cursesi_screen->curwin)
355 		for (wy = 0; wy < win->maxy; wy++) {
356 			wlp = win->lines[wy];
357 			if (wlp->flags & __ISDIRTY)
358 				wlp->hash = __hash((char *)(void *)wlp->line,
359 				    (size_t) (win->maxx * __LDATASIZE));
360 		}
361 
362 	if ((win->flags & __CLEAROK) || (curscr->flags & __CLEAROK) ||
363 	    _cursesi_screen->curwin) {
364 		if (curscr->wattr & __COLOR)
365 			__unsetattr(0);
366 		tputs(__tc_cl, 0, __cputchar);
367 		_cursesi_screen->ly = 0;
368 		_cursesi_screen->lx = 0;
369 		if (!_cursesi_screen->curwin) {
370 			curscr->flags &= ~__CLEAROK;
371 			curscr->cury = 0;
372 			curscr->curx = 0;
373 			werase(curscr);
374 		}
375 		__touchwin(win);
376 		win->flags &= ~__CLEAROK;
377 	}
378 	if (!__CA) {
379 		if (win->curx != 0)
380 			__cputchar('\n');
381 		if (!_cursesi_screen->curwin)
382 			werase(curscr);
383 	}
384 #ifdef DEBUG
385 	__CTRACE("doupdate: (%p): curwin = %d\n", win,
386 		 _cursesi_screen->curwin);
387 	__CTRACE("doupdate: \tfirstch\tlastch\n");
388 #endif
389 
390 	if (!_cursesi_screen->curwin) {
391 		/*
392 		 * Invoke quickch() only if more than a quarter of the lines
393 		 * in the window are dirty.
394 		 */
395 		for (wy = 0, dnum = 0; wy < win->maxy; wy++)
396 			if (win->lines[wy]->flags & __ISDIRTY)
397 				dnum++;
398 		if (!__noqch && dnum > (int) win->maxy / 4)
399 			quickch();
400 	}
401 
402 #ifdef DEBUG
403 	{
404 		int	i, j;
405 
406 		__CTRACE("#####################################\n");
407 		for (i = 0; i < curscr->maxy; i++) {
408 			__CTRACE("C: %d:", i);
409 			__CTRACE(" 0x%x \n", curscr->lines[i]->hash);
410 			for (j = 0; j < curscr->maxx; j++)
411 				__CTRACE("%c", curscr->lines[i]->line[j].ch);
412 			__CTRACE("\n");
413 			__CTRACE(" attr:");
414 			for (j = 0; j < curscr->maxx; j++)
415 				__CTRACE(" %x",
416 					 curscr->lines[i]->line[j].attr);
417 			__CTRACE("\n");
418 			__CTRACE("W: %d:", i);
419 			__CTRACE(" 0x%x \n", win->lines[i]->hash);
420 			__CTRACE(" 0x%x ", win->lines[i]->flags);
421 			for (j = 0; j < win->maxx; j++)
422 				__CTRACE("%c", win->lines[i]->line[j].ch);
423 			__CTRACE("\n");
424 			__CTRACE(" attr:");
425 			for (j = 0; j < win->maxx; j++)
426 				__CTRACE(" %x",
427 				    win->lines[i]->line[j].attr);
428 			__CTRACE("\n");
429 		}
430 	}
431 #endif				/* DEBUG */
432 
433 	for (wy = 0; wy < win->maxy; wy++) {
434 		wlp = win->lines[wy];
435 /* XXX: remove this debug */
436 #ifdef DEBUG
437 		__CTRACE("doupdate: wy %d\tf: %d\tl:%d\tflags %x\n", wy,
438 		    *wlp->firstchp, *wlp->lastchp, wlp->flags);
439 #endif
440 		if (!_cursesi_screen->curwin)
441 			curscr->lines[wy]->hash = wlp->hash;
442 		if (wlp->flags & __ISDIRTY) {
443 			if (makech(wy) == ERR)
444 				return (ERR);
445 			else {
446 				if (*wlp->firstchp >= 0)
447 					*wlp->firstchp = win->maxx;
448 				if (*wlp->lastchp < win->maxx)
449 					*wlp->lastchp = 0;
450 				if (*wlp->lastchp < *wlp->firstchp) {
451 #ifdef DEBUG
452 					__CTRACE("doupdate: line %d notdirty\n", wy);
453 #endif
454 					wlp->flags &= ~__ISDIRTY;
455 				}
456 			}
457 
458 		}
459 #ifdef DEBUG
460 		__CTRACE("\t%d\t%d\n", *wlp->firstchp, *wlp->lastchp);
461 #endif
462 	}
463 
464 #ifdef DEBUG
465 	__CTRACE("doupdate: ly=%d, lx=%d\n", _cursesi_screen->ly,
466 		 _cursesi_screen->lx);
467 #endif
468 
469 	if (_cursesi_screen->curwin)
470 		domvcur(_cursesi_screen->ly, _cursesi_screen->lx,
471 			(int) win->cury, (int) win->curx);
472 	else {
473 		if (win->flags & __LEAVEOK) {
474 			curscr->cury = _cursesi_screen->ly;
475 			curscr->curx = _cursesi_screen->lx;
476 		} else {
477 			domvcur(_cursesi_screen->ly, _cursesi_screen->lx,
478 				win->cury, win->curx);
479 			curscr->cury = win->cury;
480 			curscr->curx = win->curx;
481 		}
482 	}
483 
484 	/* Don't leave the screen with attributes set. */
485 	__unsetattr(0);
486 	(void) fflush(_cursesi_screen->outfd);
487 	return (OK);
488 }
489 
490 /*
491  * makech --
492  *	Make a change on the screen.
493  */
494 static int
495 makech(wy)
496 	int	wy;
497 {
498 	WINDOW	*win;
499 	static __LDATA blank = {' ', 0, ' ', 0};
500 	__LDATA *nsp, *csp, *cp, *cep;
501 	int	clsp, nlsp;	/* Last space in lines. */
502 	int	lch, wx;
503 	char	*ce;
504 	attr_t	lspc;		/* Last space colour */
505 	attr_t	off, on;
506 
507 #ifdef __GNUC__
508 	nlsp = lspc = 0;	/* XXX gcc -Wuninitialized */
509 #endif
510 	if (_cursesi_screen->curwin)
511 		win = curscr;
512 	else
513 		win = __virtscr;
514 	/* Is the cursor still on the end of the last line? */
515 	if (wy > 0 && curscr->lines[wy - 1]->flags & __ISPASTEOL) {
516 		domvcur(_cursesi_screen->ly, _cursesi_screen->lx,
517 			_cursesi_screen->ly + 1, 0);
518 		_cursesi_screen->ly++;
519 		_cursesi_screen->lx = 0;
520 	}
521 	wx = *win->lines[wy]->firstchp;
522 	if (wx < 0)
523 		wx = 0;
524 	else
525 		if (wx >= win->maxx)
526 			return (OK);
527 	lch = *win->lines[wy]->lastchp;
528 	if (lch < 0)
529 		return (OK);
530 	else
531 		if (lch >= (int) win->maxx)
532 			lch = win->maxx - 1;
533 
534 	if (_cursesi_screen->curwin)
535 		csp = &blank;
536 	else
537 		csp = &curscr->lines[wy]->line[wx];
538 
539 	nsp = &win->lines[wy]->line[wx];
540 	if (__tc_ce && !_cursesi_screen->curwin) {
541 		cp = &win->lines[wy]->line[win->maxx - 1];
542 		lspc = cp->attr & __COLOR;
543 		while (cp->ch == ' ' && cp->attr == lspc)
544 			if (cp-- <= win->lines[wy]->line)
545 				break;
546 		nlsp = cp - win->lines[wy]->line;
547 		if (nlsp < 0)
548 			nlsp = 0;
549 	}
550 	if (!_cursesi_screen->curwin)
551 		ce = __tc_ce;
552 	else
553 		ce = NULL;
554 
555 	while (wx <= lch) {
556 		if (memcmp(nsp, csp, sizeof(__LDATA)) == 0) {
557 			if (wx <= lch) {
558 				while (wx <= lch &&
559 				    memcmp(nsp, csp, sizeof(__LDATA)) == 0) {
560 					nsp++;
561 					if (!_cursesi_screen->curwin)
562 						++csp;
563 					++wx;
564 				}
565 				continue;
566 			}
567 			break;
568 		}
569 		domvcur(_cursesi_screen->ly, _cursesi_screen->lx, wy, wx);
570 
571 #ifdef DEBUG
572 		__CTRACE("makech: 1: wx = %d, ly= %d, lx = %d, newy = %d, newx = %d\n",
573 		    wx, _cursesi_screen->ly, _cursesi_screen->lx, wy, wx);
574 #endif
575 		_cursesi_screen->ly = wy;
576 		_cursesi_screen->lx = wx;
577 		while (memcmp(nsp, csp, sizeof(__LDATA)) != 0 && wx <= lch) {
578 			if (ce != NULL &&
579 			    wx >= nlsp && nsp->ch == ' ' && nsp->attr == lspc) {
580 				/* Check for clear to end-of-line. */
581 				cep = &curscr->lines[wy]->line[win->maxx - 1];
582 				while (cep->ch == ' ' && cep->attr == lspc)
583 					if (cep-- <= csp)
584 						break;
585 				clsp = cep - curscr->lines[wy]->line -
586 				    win->begx * __LDATASIZE;
587 #ifdef DEBUG
588 				__CTRACE("makech: clsp = %d, nlsp = %d\n",
589 				    clsp, nlsp);
590 #endif
591 				if (((clsp - nlsp >= strlen(__tc_ce) &&
592 				    clsp < win->maxx * __LDATASIZE) ||
593 				    wy == win->maxy - 1) &&
594 				    (!(lspc & __COLOR) ||
595 				    ((lspc & __COLOR) && __tc_ut))) {
596 					__unsetattr(0);
597 					if (__using_color &&
598 					    ((lspc & __COLOR) !=
599 					    (curscr->wattr & __COLOR)))
600 						__set_color(curscr, lspc &
601 						    __COLOR);
602 					tputs(__tc_ce, 0, __cputchar);
603 					_cursesi_screen->lx = wx + win->begx;
604 					while (wx++ <= clsp) {
605 						csp->ch = ' ';
606 						csp->attr = lspc;
607 						csp++;
608 					}
609 					return (OK);
610 				}
611 				ce = NULL;
612 			}
613 
614 #ifdef DEBUG
615 				__CTRACE("makech: have attributes %08x, need attributes %08x\n", curscr->wattr, nsp->attr);
616 #endif
617 
618 			off = ~nsp->attr & curscr->wattr;
619 
620 			/*
621 			 * Unset attributes as appropriate.  Unset first
622 			 * so that the relevant attributes can be reset
623 			 * (because 'me' unsets 'mb', 'md', 'mh', 'mk',
624 			 * 'mp' and 'mr').  Check to see if we also turn off
625 			 * standout, attributes and colour.
626 			 */
627 			if (off & __TERMATTR && __tc_me != NULL) {
628 				tputs(__tc_me, 0, __cputchar);
629 				curscr->wattr &= __mask_me;
630 				off &= __mask_me;
631 			}
632 
633 			/*
634 			 * Exit underscore mode if appropriate.
635 			 * Check to see if we also turn off standout,
636 			 * attributes and colour.
637 			 */
638 			if (off & __UNDERSCORE && __tc_ue != NULL) {
639 				tputs(__tc_ue, 0, __cputchar);
640 				curscr->wattr &= __mask_ue;
641 				off &= __mask_ue;
642 			}
643 
644 			/*
645 			 * Exit standout mode as appropriate.
646 			 * Check to see if we also turn off underscore,
647 			 * attributes and colour.
648 			 * XXX
649 			 * Should use uc if so/se not available.
650 			 */
651 			if (off & __STANDOUT && __tc_se != NULL) {
652 				tputs(__tc_se, 0, __cputchar);
653 				curscr->wattr &= __mask_se;
654 				off &= __mask_se;
655 			}
656 
657 			if (off & __ALTCHARSET && __tc_ae != NULL) {
658 				tputs(__tc_ae, 0, __cputchar);
659 				curscr->wattr &= ~__ALTCHARSET;
660 			}
661 
662 			/* Set/change colour as appropriate. */
663 			if (__using_color)
664 				__set_color(curscr, nsp->attr & __COLOR);
665 
666 			on = nsp->attr & ~curscr->wattr;
667 
668 			/*
669 			 * Enter standout mode if appropriate.
670 			 */
671 			if (on & __STANDOUT && __tc_so != NULL && __tc_se
672 			    != NULL) {
673 				tputs(__tc_so, 0, __cputchar);
674 				curscr->wattr |= __STANDOUT;
675 			}
676 
677 			/*
678 			 * Enter underscore mode if appropriate.
679 			 * XXX
680 			 * Should use uc if us/ue not available.
681 			 */
682 			if (on & __UNDERSCORE && __tc_us != NULL &&
683 			    __tc_ue != NULL) {
684 				tputs(__tc_us, 0, __cputchar);
685 				curscr->wattr |= __UNDERSCORE;
686 			}
687 
688 			/*
689 			 * Set other attributes as appropriate.
690 			 */
691 			if (__tc_me != NULL) {
692 				if (on & __BLINK && __tc_mb != NULL) {
693 					tputs(__tc_mb, 0, __cputchar);
694 					curscr->wattr |= __BLINK;
695 				}
696 				if (on & __BOLD && __tc_md != NULL) {
697 					tputs(__tc_md, 0, __cputchar);
698 					curscr->wattr |= __BOLD;
699 				}
700 				if (on & __DIM && __tc_mh != NULL) {
701 					tputs(__tc_mh, 0, __cputchar);
702 					curscr->wattr |= __DIM;
703 				}
704 				if (on & __BLANK && __tc_mk != NULL) {
705 					tputs(__tc_mk, 0, __cputchar);
706 					curscr->wattr |= __BLANK;
707 				}
708 				if (on & __PROTECT && __tc_mp != NULL) {
709 					tputs(__tc_mp, 0, __cputchar);
710 					curscr->wattr |= __PROTECT;
711 				}
712 				if (on & __REVERSE && __tc_mr != NULL) {
713 					tputs(__tc_mr, 0, __cputchar);
714 					curscr->wattr |= __REVERSE;
715 				}
716 			}
717 
718 			/* Enter/exit altcharset mode as appropriate. */
719 			if (on & __ALTCHARSET && __tc_as != NULL &&
720 			    __tc_ae != NULL) {
721 				tputs(__tc_as, 0, __cputchar);
722 				curscr->wattr |= __ALTCHARSET;
723 			}
724 
725 			wx++;
726 			if (wx >= win->maxx &&
727 			    wy == win->maxy - 1 && !_cursesi_screen->curwin)
728 				if (win->flags & __SCROLLOK) {
729 					if (win->flags & __ENDLINE)
730 						__unsetattr(1);
731 					if (!(win->flags & __SCROLLWIN)) {
732 						if (!_cursesi_screen->curwin) {
733 							csp->attr = nsp->attr;
734 							__cputchar((int)
735 							    (csp->ch =
736 							    nsp->ch));
737 						} else
738 							__cputchar((int) nsp->ch);
739 					}
740 					if (wx < curscr->maxx) {
741 						domvcur(_cursesi_screen->ly, wx,
742 						    (int) (win->maxy - 1),
743 						    (int) (win->maxx - 1));
744 					}
745 					_cursesi_screen->ly = win->maxy - 1;
746 					_cursesi_screen->lx = win->maxx - 1;
747 					return (OK);
748 				}
749 			if (wx < win->maxx || wy < win->maxy - 1 ||
750 			    !(win->flags & __SCROLLWIN)) {
751 				if (!_cursesi_screen->curwin) {
752 					csp->attr = nsp->attr;
753 					__cputchar((int) (csp->ch = nsp->ch));
754 					csp++;
755 				} else
756 					__cputchar((int) nsp->ch);
757 			}
758 #ifdef DEBUG
759 			__CTRACE("makech: putchar(%c)\n", nsp->ch & 0177);
760 #endif
761 			if (__tc_uc && ((nsp->attr & __STANDOUT) ||
762 			    (nsp->attr & __UNDERSCORE))) {
763 				__cputchar('\b');
764 				tputs(__tc_uc, 0, __cputchar);
765 			}
766 			nsp++;
767 #ifdef DEBUG
768 			__CTRACE("makech: 2: wx = %d, lx = %d\n", wx, _cursesi_screen->lx);
769 #endif
770 		}
771 		if (_cursesi_screen->lx == wx)	/* If no change. */
772 			break;
773 		_cursesi_screen->lx = wx;
774 		if (_cursesi_screen->lx >= COLS && __tc_am)
775 			_cursesi_screen->lx = COLS - 1;
776 		else
777 			if (wx >= win->maxx) {
778 				domvcur(_cursesi_screen->ly,
779 					_cursesi_screen->lx,
780 					_cursesi_screen->ly,
781 					(int) (win->maxx - 1));
782 				_cursesi_screen->lx = win->maxx - 1;
783 			}
784 #ifdef DEBUG
785 		__CTRACE("makech: 3: wx = %d, lx = %d\n", wx,
786 			 _cursesi_screen->lx);
787 #endif
788 	}
789 
790 	return (OK);
791 }
792 
793 /*
794  * domvcur --
795  *	Do a mvcur, leaving attributes if necessary.
796  */
797 static void
798 domvcur(oy, ox, ny, nx)
799 	int	oy, ox, ny, nx;
800 {
801 	__unsetattr(1);
802 	__mvcur(oy, ox, ny, nx, 1);
803 }
804 
805 /*
806  * Quickch() attempts to detect a pattern in the change of the window
807  * in order to optimize the change, e.g., scroll n lines as opposed to
808  * repainting the screen line by line.
809  */
810 
811 static __LDATA buf[128];
812 static  u_int last_hash;
813 static  size_t last_hash_len;
814 #define BLANKSIZE (sizeof(buf) / sizeof(buf[0]))
815 
816 static void
817 quickch(void)
818 {
819 #define THRESH		(int) __virtscr->maxy / 4
820 
821 	__LINE *clp, *tmp1, *tmp2;
822 	int	bsize, curs, curw, starts, startw, i, j;
823 	int	n, target, cur_period, bot, top, sc_region;
824 	u_int	blank_hash;
825 	attr_t	bcolor;
826 
827 #ifdef __GNUC__
828 	curs = curw = starts = startw = 0;	/* XXX gcc -Wuninitialized */
829 #endif
830 	/*
831 	 * Find how many lines from the top of the screen are unchanged.
832 	 */
833 	for (top = 0; top < __virtscr->maxy; top++)
834 		if (__virtscr->lines[top]->flags & __ISDIRTY &&
835 		    (__virtscr->lines[top]->hash != curscr->lines[top]->hash ||
836 		     memcmp(__virtscr->lines[top]->line,
837 			  curscr->lines[top]->line,
838 			  (size_t) __virtscr->maxx * __LDATASIZE) != 0))
839 			break;
840 		else
841 			__virtscr->lines[top]->flags &= ~__ISDIRTY;
842 	/*
843 	 * Find how many lines from bottom of screen are unchanged.
844 	 */
845 	for (bot = __virtscr->maxy - 1; bot >= 0; bot--)
846 		if (__virtscr->lines[bot]->flags & __ISDIRTY &&
847 		    (__virtscr->lines[bot]->hash != curscr->lines[bot]->hash ||
848 		     memcmp(__virtscr->lines[bot]->line,
849 			  curscr->lines[bot]->line,
850 			  (size_t) __virtscr->maxx * __LDATASIZE) != 0))
851 			break;
852 		else
853 			__virtscr->lines[bot]->flags &= ~__ISDIRTY;
854 
855 	/*
856 	 * Work round an xterm bug where inserting lines causes all the
857 	 * inserted lines to be covered with the background colour we
858 	 * set on the first line (even if we unset it for subsequent
859 	 * lines).
860 	 */
861 	bcolor = __virtscr->lines[min(top,
862 	    __virtscr->maxy - 1)]->line[0].attr & __COLOR;
863 	for (i = top + 1, j = 0; i < bot; i++) {
864 		if ((__virtscr->lines[i]->line[0].attr & __COLOR) != bcolor) {
865 			bcolor = __virtscr->lines[i]->line[__virtscr->maxx].
866 			    attr & __COLOR;
867 			j = i - top;
868 		} else
869 			break;
870 	}
871 	top += j;
872 
873 #ifdef NO_JERKINESS
874 	/*
875 	 * If we have a bottom unchanged region return.  Scrolling the
876 	 * bottom region up and then back down causes a screen jitter.
877 	 * This will increase the number of characters sent to the screen
878 	 * but it looks better.
879 	 */
880 	if (bot < __virtscr->maxy - 1)
881 		return;
882 #endif				/* NO_JERKINESS */
883 
884 	/*
885 	 * Search for the largest block of text not changed.
886 	 * Invariants of the loop:
887 	 * - Startw is the index of the beginning of the examined block in
888 	 *   __virtscr.
889 	 * - Starts is the index of the beginning of the examined block in
890 	 *   curscr.
891 	 * - Curw is the index of one past the end of the exmined block in
892 	 *   __virtscr.
893 	 * - Curs is the index of one past the end of the exmined block in
894 	 *   curscr.
895 	 * - bsize is the current size of the examined block.
896 	*/
897 
898 	for (bsize = bot - top; bsize >= THRESH; bsize--) {
899 		for (startw = top; startw <= bot - bsize; startw++)
900 			for (starts = top; starts <= bot - bsize;
901 			    starts++) {
902 				for (curw = startw, curs = starts;
903 				    curs < starts + bsize; curw++, curs++)
904 					if (__virtscr->lines[curw]->hash !=
905 					    curscr->lines[curs]->hash)
906 						break;
907 				if (curs != starts + bsize)
908 					continue;
909 				for (curw = startw, curs = starts;
910 				    curs < starts + bsize; curw++, curs++)
911 					if (memcmp(__virtscr->lines[curw]->line,
912 					    curscr->lines[curs]->line,
913 					    (size_t) __virtscr->maxx *
914 					    __LDATASIZE) != 0)
915 						break;
916 				if (curs == starts + bsize)
917 					goto done;
918 			}
919 	}
920 done:
921 
922 	/* Did not find anything */
923 	if (bsize < THRESH)
924 		return;
925 
926 #ifdef DEBUG
927 	__CTRACE("quickch:bsize=%d,starts=%d,startw=%d,curw=%d,curs=%d,top=%d,bot=%d\n",
928 	    bsize, starts, startw, curw, curs, top, bot);
929 #endif
930 
931 	/*
932 	 * Make sure that there is no overlap between the bottom and top
933 	 * regions and the middle scrolled block.
934 	 */
935 	if (bot < curs)
936 		bot = curs - 1;
937 	if (top > starts)
938 		top = starts;
939 
940 	n = startw - starts;
941 
942 #ifdef DEBUG
943 	__CTRACE("#####################################\n");
944 	for (i = 0; i < curscr->maxy; i++) {
945 		__CTRACE("C: %d:", i);
946 		__CTRACE(" 0x%x \n", curscr->lines[i]->hash);
947 		for (j = 0; j < curscr->maxx; j++)
948 			__CTRACE("%c", curscr->lines[i]->line[j].ch);
949 		__CTRACE("\n");
950 		__CTRACE(" attr:");
951 		for (j = 0; j < curscr->maxx; j++)
952 			__CTRACE(" %x", curscr->lines[i]->line[j].attr);
953 		__CTRACE("\n");
954 		__CTRACE("W: %d:", i);
955 		__CTRACE(" 0x%x \n", __virtscr->lines[i]->hash);
956 		__CTRACE(" 0x%x ", __virtscr->lines[i]->flags);
957 		for (j = 0; j < __virtscr->maxx; j++)
958 			__CTRACE("%c", __virtscr->lines[i]->line[j].ch);
959 		__CTRACE("\n");
960 		__CTRACE(" attr:");
961 		for (j = 0; j < __virtscr->maxx; j++)
962 			__CTRACE(" %x", __virtscr->lines[i]->line[j].attr);
963 		__CTRACE("\n");
964 	}
965 #endif
966 
967 	if (buf[0].ch != ' ') {
968 		for (i = 0; i < BLANKSIZE; i++) {
969 			buf[i].ch = ' ';
970 			buf[i].bch = ' ';
971 			buf[i].attr = 0;
972 			buf[i].battr = 0;
973 		}
974 	}
975 
976 	if (__virtscr->maxx != last_hash_len) {
977 		blank_hash = 0;
978 		for (i = __virtscr->maxx; i > BLANKSIZE; i -= BLANKSIZE) {
979 			blank_hash = __hash_more((char *)(void *)buf, sizeof(buf),
980 			    blank_hash);
981 		}
982 		blank_hash = __hash_more((char *)(void *)buf,
983 		    i * sizeof(buf[0]), blank_hash);
984 		/* cache result in static data - screen width doesn't change often */
985 		last_hash_len = __virtscr->maxx;
986 		last_hash = blank_hash;
987 	} else
988 		blank_hash = last_hash;
989 
990 	/*
991 	 * Perform the rotation to maintain the consistency of curscr.
992 	 * This is hairy since we are doing an *in place* rotation.
993 	 * Invariants of the loop:
994 	 * - I is the index of the current line.
995 	 * - Target is the index of the target of line i.
996 	 * - Tmp1 points to current line (i).
997 	 * - Tmp2 and points to target line (target);
998 	 * - Cur_period is the index of the end of the current period.
999 	 *   (see below).
1000 	 *
1001 	 * There are 2 major issues here that make this rotation non-trivial:
1002 	 * 1.  Scrolling in a scrolling region bounded by the top
1003 	 *     and bottom regions determined (whose size is sc_region).
1004 	 * 2.  As a result of the use of the mod function, there may be a
1005 	 *     period introduced, i.e., 2 maps to 4, 4 to 6, n-2 to 0, and
1006 	 *     0 to 2, which then causes all odd lines not to be rotated.
1007 	 *     To remedy this, an index of the end ( = beginning) of the
1008 	 *     current 'period' is kept, cur_period, and when it is reached,
1009 	 *     the next period is started from cur_period + 1 which is
1010 	 *     guaranteed not to have been reached since that would mean that
1011 	 *     all records would have been reached. (think about it...).
1012 	 *
1013 	 * Lines in the rotation can have 3 attributes which are marked on the
1014 	 * line so that curscr is consistent with the visual screen.
1015 	 * 1.  Not dirty -- lines inside the scrolled block, top region or
1016 	 *                  bottom region.
1017 	 * 2.  Blank lines -- lines in the differential of the scrolling
1018 	 *		      region adjacent to top and bot regions
1019 	 *                    depending on scrolling direction.
1020 	 * 3.  Dirty line -- all other lines are marked dirty.
1021 	 */
1022 	sc_region = bot - top + 1;
1023 	i = top;
1024 	tmp1 = curscr->lines[top];
1025 	cur_period = top;
1026 	for (j = top; j <= bot; j++) {
1027 		target = (i - top + n + sc_region) % sc_region + top;
1028 		tmp2 = curscr->lines[target];
1029 		curscr->lines[target] = tmp1;
1030 		/* Mark block as clean and blank out scrolled lines. */
1031 		clp = curscr->lines[target];
1032 #ifdef DEBUG
1033 		__CTRACE("quickch: n=%d startw=%d curw=%d i = %d target=%d ",
1034 		    n, startw, curw, i, target);
1035 #endif
1036 		if ((target >= startw && target < curw) || target < top
1037 		    || target > bot) {
1038 #ifdef DEBUG
1039 			__CTRACE("-- notdirty\n");
1040 #endif
1041 			__virtscr->lines[target]->flags &= ~__ISDIRTY;
1042 		} else
1043 			if ((n > 0 && target >= top && target < top + n) ||
1044 			    (n < 0 && target <= bot && target > bot + n)) {
1045 				if (clp->hash != blank_hash || memcmp(clp->line,
1046 				    clp->line + 1, (__virtscr->maxx - 1) *
1047 				    __LDATASIZE) || memcmp(clp->line, buf,
1048 				    __LDATASIZE)) {
1049 					for (i = __virtscr->maxx; i > BLANKSIZE;
1050 					    i -= BLANKSIZE) {
1051 						(void)memcpy(clp->line + i -
1052 						    BLANKSIZE, buf, sizeof(buf));
1053 					}
1054 					(void)memcpy(clp->line , buf, i *
1055 					    sizeof(buf[0]));
1056 #ifdef DEBUG
1057 					__CTRACE("-- blanked out: dirty\n");
1058 #endif
1059 					clp->hash = blank_hash;
1060 					__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
1061 				} else {
1062 #ifdef DEBUG
1063 					__CTRACE(" -- blank line already: dirty\n");
1064 #endif
1065 					__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
1066 				}
1067 			} else {
1068 #ifdef DEBUG
1069 				__CTRACE(" -- dirty\n");
1070 #endif
1071 				__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
1072 			}
1073 		if (target == cur_period) {
1074 			i = target + 1;
1075 			tmp1 = curscr->lines[i];
1076 			cur_period = i;
1077 		} else {
1078 			tmp1 = tmp2;
1079 			i = target;
1080 		}
1081 	}
1082 #ifdef DEBUG
1083 	__CTRACE("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$\n");
1084 	for (i = 0; i < curscr->maxy; i++) {
1085 		__CTRACE("C: %d:", i);
1086 		for (j = 0; j < curscr->maxx; j++)
1087 			__CTRACE("%c", curscr->lines[i]->line[j].ch);
1088 		__CTRACE("\n");
1089 		__CTRACE("W: %d:", i);
1090 		for (j = 0; j < __virtscr->maxx; j++)
1091 			__CTRACE("%c", __virtscr->lines[i]->line[j].ch);
1092 		__CTRACE("\n");
1093 	}
1094 #endif
1095 	if (n != 0)
1096 		scrolln(starts, startw, curs, bot, top);
1097 }
1098 
1099 /*
1100  * scrolln --
1101  *	Scroll n lines, where n is starts - startw.
1102  */
1103 static void /* ARGSUSED */
1104 scrolln(starts, startw, curs, bot, top)
1105 	int	starts, startw, curs, bot, top;
1106 {
1107 	int	i, oy, ox, n;
1108 
1109 	oy = curscr->cury;
1110 	ox = curscr->curx;
1111 	n = starts - startw;
1112 
1113 	/*
1114 	 * XXX
1115 	 * The initial tests that set __noqch don't let us reach here unless
1116 	 * we have either cs + ho + SF/sf/SR/sr, or AL + DL.  SF/sf and SR/sr
1117 	 * scrolling can only shift the entire scrolling region, not just a
1118 	 * part of it, which means that the quickch() routine is going to be
1119 	 * sadly disappointed in us if we don't have cs as well.
1120 	 *
1121 	 * If cs, ho and SF/sf are set, can use the scrolling region.  Because
1122 	 * the cursor position after cs is undefined, we need ho which gives us
1123 	 * the ability to move to somewhere without knowledge of the current
1124 	 * location of the cursor.  Still call __mvcur() anyway, to update its
1125 	 * idea of where the cursor is.
1126 	 *
1127 	 * When the scrolling region has been set, the cursor has to be at the
1128 	 * last line of the region to make the scroll happen.
1129 	 *
1130 	 * Doing SF/SR or AL/DL appears faster on the screen than either sf/sr
1131 	 * or AL/DL, and, some terminals have AL/DL, sf/sr, and cs, but not
1132 	 * SF/SR.  So, if we're scrolling almost all of the screen, try and use
1133 	 * AL/DL, otherwise use the scrolling region.  The "almost all" is a
1134 	 * shameless hack for vi.
1135 	 */
1136 	if (n > 0) {
1137 		if (__tc_cs != NULL && __tc_ho != NULL && (__tc_SF != NULL ||
1138 		    ((__tc_AL == NULL || __tc_DL == NULL ||
1139 		    top > 3 || bot + 3 < __virtscr->maxy) &&
1140 		    __tc_sf != NULL))) {
1141 			tputs(__tscroll(__tc_cs, top, bot + 1), 0, __cputchar);
1142 			__mvcur(oy, ox, 0, 0, 1);
1143 			tputs(__tc_ho, 0, __cputchar);
1144 			__mvcur(0, 0, bot, 0, 1);
1145 			if (__tc_SF != NULL)
1146 				tputs(__tscroll(__tc_SF, n, 0), 0, __cputchar);
1147 			else
1148 				for (i = 0; i < n; i++)
1149 					tputs(__tc_sf, 0, __cputchar);
1150 			tputs(__tscroll(__tc_cs, 0, (int) __virtscr->maxy), 0,
1151 			    __cputchar);
1152 			__mvcur(bot, 0, 0, 0, 1);
1153 			tputs(__tc_ho, 0, __cputchar);
1154 			__mvcur(0, 0, oy, ox, 1);
1155 			return;
1156 		}
1157 
1158 		/* Scroll up the block. */
1159 		if (__tc_SF != NULL && top == 0) {
1160 			__mvcur(oy, ox, bot, 0, 1);
1161 			tputs(__tscroll(__tc_SF, n, 0), 0, __cputchar);
1162 		} else
1163 			if (__tc_DL != NULL) {
1164 				__mvcur(oy, ox, top, 0, 1);
1165 				tputs(__tscroll(__tc_DL, n, 0), 0, __cputchar);
1166 			} else
1167 				if (__tc_dl != NULL) {
1168 					__mvcur(oy, ox, top, 0, 1);
1169 					for (i = 0; i < n; i++)
1170 						tputs(__tc_dl, 0, __cputchar);
1171 				} else
1172 					if (__tc_sf != NULL && top == 0) {
1173 						__mvcur(oy, ox, bot, 0, 1);
1174 						for (i = 0; i < n; i++)
1175 							tputs(__tc_sf, 0,
1176 							    __cputchar);
1177 					} else
1178 						abort();
1179 
1180 		/* Push down the bottom region. */
1181 		__mvcur(top, 0, bot - n + 1, 0, 1);
1182 		if (__tc_AL != NULL)
1183 			tputs(__tscroll(__tc_AL, n, 0), 0, __cputchar);
1184 		else
1185 			if (__tc_al != NULL)
1186 				for (i = 0; i < n; i++)
1187 					tputs(__tc_al, 0, __cputchar);
1188 			else
1189 				abort();
1190 		__mvcur(bot - n + 1, 0, oy, ox, 1);
1191 	} else {
1192 		/*
1193 		 * !!!
1194 		 * n < 0
1195 		 *
1196 		 * If cs, ho and SR/sr are set, can use the scrolling region.
1197 		 * See the above comments for details.
1198 		 */
1199 		if (__tc_cs != NULL && __tc_ho != NULL && (__tc_SR != NULL ||
1200 		    ((__tc_AL == NULL || __tc_DL == NULL || top > 3 ||
1201 		    bot + 3 < __virtscr->maxy) && __tc_sr != NULL))) {
1202 			tputs(__tscroll(__tc_cs, top, bot + 1), 0, __cputchar);
1203 			__mvcur(oy, ox, 0, 0, 1);
1204 			tputs(__tc_ho, 0, __cputchar);
1205 			__mvcur(0, 0, top, 0, 1);
1206 
1207 			if (__tc_SR != NULL)
1208 				tputs(__tscroll(__tc_SR, -n, 0), 0, __cputchar);
1209 			else
1210 				for (i = n; i < 0; i++)
1211 					tputs(__tc_sr, 0, __cputchar);
1212 			tputs(__tscroll(__tc_cs, 0, (int) __virtscr->maxy), 0,
1213 			    __cputchar);
1214 			__mvcur(top, 0, 0, 0, 1);
1215 			tputs(__tc_ho, 0, __cputchar);
1216 			__mvcur(0, 0, oy, ox, 1);
1217 			return;
1218 		}
1219 
1220 		/* Preserve the bottom lines. */
1221 		__mvcur(oy, ox, bot + n + 1, 0, 1);
1222 		if (__tc_SR != NULL && bot == __virtscr->maxy)
1223 			tputs(__tscroll(__tc_SR, -n, 0), 0, __cputchar);
1224 		else
1225 			if (__tc_DL != NULL)
1226 				tputs(__tscroll(__tc_DL, -n, 0), 0, __cputchar);
1227 			else
1228 				if (__tc_dl != NULL)
1229 					for (i = n; i < 0; i++)
1230 						tputs(__tc_dl, 0, __cputchar);
1231 				else
1232 					if (__tc_sr != NULL &&
1233 					    bot == __virtscr->maxy)
1234 						for (i = n; i < 0; i++)
1235 							tputs(__tc_sr, 0,
1236 							    __cputchar);
1237 					else
1238 						abort();
1239 
1240 		/* Scroll the block down. */
1241 		__mvcur(bot + n + 1, 0, top, 0, 1);
1242 		if (__tc_AL != NULL)
1243 			tputs(__tscroll(__tc_AL, -n, 0), 0, __cputchar);
1244 		else
1245 			if (__tc_al != NULL)
1246 				for (i = n; i < 0; i++)
1247 					tputs(__tc_al, 0, __cputchar);
1248 			else
1249 				abort();
1250 		__mvcur(top, 0, oy, ox, 1);
1251 	}
1252 }
1253 
1254 /*
1255  * __unsetattr --
1256  *	Unset attributes on curscr.  Leave standout, attribute and colour
1257  *	modes if necessary (!ms).  Always leave altcharset (xterm at least
1258  *	ignores a cursor move if we don't).
1259  */
1260 void /* ARGSUSED */
1261 __unsetattr(int checkms)
1262 {
1263 	int	isms;
1264 
1265 	if (checkms)
1266 		if (!__tc_ms) {
1267 			isms = 1;
1268 		} else {
1269 			isms = 0;
1270 		}
1271 	else
1272 		isms = 1;
1273 #ifdef DEBUG
1274 	__CTRACE("__unsetattr: checkms = %d, ms = %s, wattr = %08x\n",
1275 	    checkms, __tc_ms ? "TRUE" : "FALSE", curscr->wattr);
1276 #endif
1277 
1278 	/*
1279          * Don't leave the screen in standout mode (check against ms).  Check
1280 	 * to see if we also turn off underscore, attributes and colour.
1281 	 */
1282 	if (curscr->wattr & __STANDOUT && isms) {
1283 		tputs(__tc_se, 0, __cputchar);
1284 		curscr->wattr &= __mask_se;
1285 	}
1286 	/*
1287 	 * Don't leave the screen in underscore mode (check against ms).
1288 	 * Check to see if we also turn off attributes.  Assume that we
1289 	 * also turn off colour.
1290 	 */
1291 	if (curscr->wattr & __UNDERSCORE && isms) {
1292 		tputs(__tc_ue, 0, __cputchar);
1293 		curscr->wattr &= __mask_ue;
1294 	}
1295 	/*
1296 	 * Don't leave the screen with attributes set (check against ms).
1297 	 * Assume that also turn off colour.
1298 	 */
1299 	if (curscr->wattr & __TERMATTR && isms) {
1300 		tputs(__tc_me, 0, __cputchar);
1301 		curscr->wattr &= __mask_me;
1302 	}
1303 	/* Don't leave the screen with altcharset set (don't check ms). */
1304 	if (curscr->wattr & __ALTCHARSET) {
1305 		tputs(__tc_ae, 0, __cputchar);
1306 		curscr->wattr &= ~__ALTCHARSET;
1307 	}
1308 	/* Don't leave the screen with colour set (check against ms). */
1309 	if (__using_color && isms)
1310 		__unset_color(curscr);
1311 }
1312