xref: /netbsd-src/lib/libcurses/refresh.c (revision c62a74e6d5cfb2fb5034e98b983da7e2fc87709d)
1 /*	$NetBSD: refresh.c,v 1.51 2003/01/12 12:53:51 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 1.51 2003/01/12 12:53:51 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 				if (wlp->line[wx].attr & __COLOR)
190 					vlp->line[x_off].attr |=
191 					    wlp->line[wx].battr & ~__COLOR;
192 				else
193 					vlp->line[x_off].attr |=
194 					    wlp->line[wx].battr;
195 				if (wlp->line[wx].ch == ' ' &&
196 				    wlp->line[wx].bch != ' ')
197 					vlp->line[x_off].ch
198 					    = wlp->line[wx].bch;
199 				else
200 					vlp->line[x_off].ch
201 					    = wlp->line[wx].ch;
202 			}
203 
204 			/* Set flags on "__virtscr" and unset on "win". */
205 			if (wlp->flags & __ISPASTEOL)
206 				vlp->flags |= __ISPASTEOL;
207 			else
208 				vlp->flags &= ~__ISPASTEOL;
209 			if (wlp->flags & __ISDIRTY)
210 				vlp->flags |= __ISDIRTY;
211 
212 #ifdef DEBUG
213 			__CTRACE("win: firstch = %d, lastch = %d\n",
214 			    *wlp->firstchp, *wlp->lastchp);
215 #endif
216 			/* Set change pointers on "__virtscr". */
217 			if (*vlp->firstchp >
218 			    *wlp->firstchp + wbegx - win->ch_off)
219 				*vlp->firstchp =
220 				    *wlp->firstchp + wbegx - win->ch_off;
221 			if (*vlp->lastchp <
222 			    *wlp->lastchp + wbegx - win->ch_off)
223 				*vlp->lastchp =
224 				    *wlp->lastchp + wbegx - win->ch_off;
225 #ifdef DEBUG
226 			__CTRACE("__virtscr: firstch = %d, lastch = %d\n",
227 			    *vlp->firstchp, *vlp->lastchp);
228 #endif
229 			/*
230 			 * Unset change pointers only if a window, as a pad
231 			 * can be displayed again without any of the contents
232 			 * changing.
233 			 */
234 			if (!(win->flags & __ISPAD)) {
235 				/* Set change pointers on "win". */
236 				if (*wlp->firstchp >= win->ch_off)
237 					*wlp->firstchp = maxx + win->ch_off;
238 				if (*wlp->lastchp < maxx + win->ch_off)
239 					*wlp->lastchp = win->ch_off;
240 				if (*wlp->lastchp < *wlp->firstchp) {
241 #ifdef DEBUG
242 					__CTRACE("wnoutrefresh: line %d notdirty\n", wy);
243 #endif
244 					wlp->flags &= ~__ISDIRTY;
245 				}
246 			}
247 		}
248 	}
249 
250 	return (OK);
251 }
252 
253 /*
254  * wrefresh --
255  *	Make the current screen look like "win" over the area covered by
256  *	win.
257  */
258 int
259 wrefresh(WINDOW *win)
260 {
261 	int retval;
262 
263 #ifdef DEBUG
264 	__CTRACE("wrefresh: win %0.2o\n", win);
265 #endif
266 
267 	_cursesi_screen->curwin = (win == _cursesi_screen->curscr);
268 	if (!_cursesi_screen->curwin)
269 		retval = _cursesi_wnoutrefresh(_cursesi_screen, win, 0, 0,
270 		    win->begy, win->begx, win->maxy, win->maxx);
271 	else
272 		retval = OK;
273 	if (retval == OK) {
274 		retval = doupdate();
275 		if (!win->flags & __LEAVEOK) {
276 			win->cury = max(0, curscr->cury - win->begy);
277 			win->curx = max(0, curscr->curx - win->begx);
278 		}
279 	}
280 	_cursesi_screen->curwin = 0;
281 	return(retval);
282 }
283 
284  /*
285  * prefresh --
286  *	Make the current screen look like "pad" over the area coverd by
287  *	the specified area of pad.
288  */
289 int
290 prefresh(WINDOW *pad, int pbegy, int pbegx, int sbegy, int sbegx,
291     int smaxy, int smaxx)
292 {
293 	int retval;
294 
295 #ifdef DEBUG
296 	__CTRACE("prefresh: pad %0.2o, flags 0x%08x\n", pad, pad->flags);
297 #endif
298 
299 	/* Use pnoutrefresh() to avoid duplicating code here */
300 	retval = pnoutrefresh(pad, pbegy, pbegx, sbegy, sbegx, smaxy, smaxx);
301 	if (retval == OK) {
302 		retval = doupdate();
303 		if (!pad->flags & __LEAVEOK) {
304 			pad->cury = max(0, curscr->cury - pad->begy);
305 			pad->curx = max(0, curscr->curx - pad->begx);
306 		}
307 	}
308 	return(retval);
309 }
310 
311 /*
312  * doupdate --
313  *	Make the current screen look like the virtual window "__virtscr".
314  */
315 int
316 doupdate(void)
317 {
318 	WINDOW	*win;
319 	__LINE	*wlp;
320 	short	 wy;
321 	int	 dnum;
322 
323 	/* Check if we need to restart ... */
324 	if (_cursesi_screen->endwin)
325 		__restartwin();
326 
327 	if (_cursesi_screen->curwin)
328 		win = curscr;
329 	else
330 		win = _cursesi_screen->__virtscr;
331 
332 	/* Initialize loop parameters. */
333 	_cursesi_screen->ly = curscr->cury;
334 	_cursesi_screen->lx = curscr->curx;
335 	wy = 0;
336 
337 	if (!_cursesi_screen->curwin)
338 		for (wy = 0; wy < win->maxy; wy++) {
339 			wlp = win->lines[wy];
340 			if (wlp->flags & __ISDIRTY)
341 				wlp->hash = __hash((char *)(void *)wlp->line,
342 				    (size_t) (win->maxx * __LDATASIZE));
343 		}
344 
345 	if ((win->flags & __CLEAROK) || (curscr->flags & __CLEAROK) ||
346 	    _cursesi_screen->curwin) {
347 		if (curscr->wattr & __COLOR)
348 			__unsetattr(0);
349 		tputs(__tc_cl, 0, __cputchar);
350 		_cursesi_screen->ly = 0;
351 		_cursesi_screen->lx = 0;
352 		if (!_cursesi_screen->curwin) {
353 			curscr->flags &= ~__CLEAROK;
354 			curscr->cury = 0;
355 			curscr->curx = 0;
356 			werase(curscr);
357 		}
358 		__touchwin(win);
359 		win->flags &= ~__CLEAROK;
360 	}
361 	if (!__CA) {
362 		if (win->curx != 0)
363 			__cputchar('\n');
364 		if (!_cursesi_screen->curwin)
365 			werase(curscr);
366 	}
367 #ifdef DEBUG
368 	__CTRACE("doupdate: (%0.2o): curwin = %d\n", win,
369 		 _cursesi_screen->curwin);
370 	__CTRACE("doupdate: \tfirstch\tlastch\n");
371 #endif
372 
373 	if (!_cursesi_screen->curwin) {
374 		/*
375 		 * Invoke quickch() only if more than a quarter of the lines
376 		 * in the window are dirty.
377 		 */
378 		for (wy = 0, dnum = 0; wy < win->maxy; wy++)
379 			if (win->lines[wy]->flags & __ISDIRTY)
380 				dnum++;
381 		if (!__noqch && dnum > (int) win->maxy / 4)
382 			quickch();
383 	}
384 
385 #ifdef DEBUG
386 	{
387 		int	i, j;
388 
389 		__CTRACE("#####################################\n");
390 		for (i = 0; i < curscr->maxy; i++) {
391 			__CTRACE("C: %d:", i);
392 			__CTRACE(" 0x%x \n", curscr->lines[i]->hash);
393 			for (j = 0; j < curscr->maxx; j++)
394 				__CTRACE("%c", curscr->lines[i]->line[j].ch);
395 			__CTRACE("\n");
396 			__CTRACE(" attr:");
397 			for (j = 0; j < curscr->maxx; j++)
398 				__CTRACE(" %x",
399 					 curscr->lines[i]->line[j].attr);
400 			__CTRACE("\n");
401 			__CTRACE("W: %d:", i);
402 			__CTRACE(" 0x%x \n", win->lines[i]->hash);
403 			__CTRACE(" 0x%x ", win->lines[i]->flags);
404 			for (j = 0; j < win->maxx; j++)
405 				__CTRACE("%c", win->lines[i]->line[j].ch);
406 			__CTRACE("\n");
407 			__CTRACE(" attr:");
408 			for (j = 0; j < win->maxx; j++)
409 				__CTRACE(" %x",
410 				    win->lines[i]->line[j].attr);
411 			__CTRACE("\n");
412 		}
413 	}
414 #endif				/* DEBUG */
415 
416 	for (wy = 0; wy < win->maxy; wy++) {
417 		wlp = win->lines[wy];
418 /* XXX: remove this debug */
419 #ifdef DEBUG
420 		__CTRACE("doupdate: wy %d\tf: %d\tl:%d\tflags %x\n", wy,
421 		    *wlp->firstchp, *wlp->lastchp, wlp->flags);
422 #endif
423 		if (!_cursesi_screen->curwin)
424 			curscr->lines[wy]->hash = wlp->hash;
425 		if (wlp->flags & __ISDIRTY) {
426 			if (makech(wy) == ERR)
427 				return (ERR);
428 			else {
429 				if (*wlp->firstchp >= 0)
430 					*wlp->firstchp = win->maxx;
431 				if (*wlp->lastchp < win->maxx)
432 					*wlp->lastchp = 0;
433 				if (*wlp->lastchp < *wlp->firstchp) {
434 #ifdef DEBUG
435 					__CTRACE("doupdate: line %d notdirty\n", wy);
436 #endif
437 					wlp->flags &= ~__ISDIRTY;
438 				}
439 			}
440 
441 		}
442 #ifdef DEBUG
443 		__CTRACE("\t%d\t%d\n", *wlp->firstchp, *wlp->lastchp);
444 #endif
445 	}
446 
447 #ifdef DEBUG
448 	__CTRACE("doupdate: ly=%d, lx=%d\n", _cursesi_screen->ly,
449 		 _cursesi_screen->lx);
450 #endif
451 
452 	if (_cursesi_screen->curwin)
453 		domvcur(_cursesi_screen->ly, _cursesi_screen->lx,
454 			(int) win->cury, (int) win->curx);
455 	else {
456 		if (win->flags & __LEAVEOK) {
457 			curscr->cury = _cursesi_screen->ly;
458 			curscr->curx = _cursesi_screen->lx;
459 		} else {
460 			domvcur(_cursesi_screen->ly, _cursesi_screen->lx,
461 				win->cury, win->curx);
462 			curscr->cury = win->cury;
463 			curscr->curx = win->curx;
464 		}
465 	}
466 
467 	/* Don't leave the screen with attributes set. */
468 	__unsetattr(0);
469 	(void) fflush(_cursesi_screen->outfd);
470 	return (OK);
471 }
472 
473 /*
474  * makech --
475  *	Make a change on the screen.
476  */
477 static int
478 makech(wy)
479 	int	wy;
480 {
481 	WINDOW	*win;
482 	static __LDATA blank = {' ', 0, ' ', 0};
483 	__LDATA *nsp, *csp, *cp, *cep;
484 	int	clsp, nlsp;	/* Last space in lines. */
485 	int	lch, wx;
486 	char	*ce;
487 	attr_t	lspc;		/* Last space colour */
488 	attr_t	off, on;
489 
490 #ifdef __GNUC__
491 	nlsp = lspc = 0;	/* XXX gcc -Wuninitialized */
492 #endif
493 	if (_cursesi_screen->curwin)
494 		win = curscr;
495 	else
496 		win = __virtscr;
497 	/* Is the cursor still on the end of the last line? */
498 	if (wy > 0 && curscr->lines[wy - 1]->flags & __ISPASTEOL) {
499 		domvcur(_cursesi_screen->ly, _cursesi_screen->lx,
500 			_cursesi_screen->ly + 1, 0);
501 		_cursesi_screen->ly++;
502 		_cursesi_screen->lx = 0;
503 	}
504 	wx = *win->lines[wy]->firstchp;
505 	if (wx < 0)
506 		wx = 0;
507 	else
508 		if (wx >= win->maxx)
509 			return (OK);
510 	lch = *win->lines[wy]->lastchp;
511 	if (lch < 0)
512 		return (OK);
513 	else
514 		if (lch >= (int) win->maxx)
515 			lch = win->maxx - 1;
516 
517 	if (_cursesi_screen->curwin)
518 		csp = &blank;
519 	else
520 		csp = &curscr->lines[wy]->line[wx];
521 
522 	nsp = &win->lines[wy]->line[wx];
523 	if (__tc_ce && !_cursesi_screen->curwin) {
524 		cp = &win->lines[wy]->line[win->maxx - 1];
525 		lspc = cp->attr & __COLOR;
526 		while (cp->ch == ' ' && cp->attr == lspc)
527 			if (cp-- <= win->lines[wy]->line)
528 				break;
529 		nlsp = cp - win->lines[wy]->line;
530 		if (nlsp < 0)
531 			nlsp = 0;
532 	}
533 	if (!_cursesi_screen->curwin)
534 		ce = __tc_ce;
535 	else
536 		ce = NULL;
537 
538 	while (wx <= lch) {
539 		if (memcmp(nsp, csp, sizeof(__LDATA)) == 0) {
540 			if (wx <= lch) {
541 				while (wx <= lch &&
542 				    memcmp(nsp, csp, sizeof(__LDATA)) == 0) {
543 					nsp++;
544 					if (!_cursesi_screen->curwin)
545 						++csp;
546 					++wx;
547 				}
548 				continue;
549 			}
550 			break;
551 		}
552 		domvcur(_cursesi_screen->ly, _cursesi_screen->lx, wy, wx);
553 
554 #ifdef DEBUG
555 		__CTRACE("makech: 1: wx = %d, ly= %d, lx = %d, newy = %d, newx = %d\n",
556 		    wx, _cursesi_screen->ly, _cursesi_screen->lx, wy, wx);
557 #endif
558 		_cursesi_screen->ly = wy;
559 		_cursesi_screen->lx = wx;
560 		while (memcmp(nsp, csp, sizeof(__LDATA)) != 0 && wx <= lch) {
561 			if (ce != NULL &&
562 			    wx >= nlsp && nsp->ch == ' ' && nsp->attr == lspc) {
563 				/* Check for clear to end-of-line. */
564 				cep = &curscr->lines[wy]->line[win->maxx - 1];
565 				while (cep->ch == ' ' && cep->attr == lspc)
566 					if (cep-- <= csp)
567 						break;
568 				clsp = cep - curscr->lines[wy]->line -
569 				    win->begx * __LDATASIZE;
570 #ifdef DEBUG
571 				__CTRACE("makech: clsp = %d, nlsp = %d\n",
572 				    clsp, nlsp);
573 #endif
574 				if (((clsp - nlsp >= strlen(__tc_ce) &&
575 				    clsp < win->maxx * __LDATASIZE) ||
576 				    wy == win->maxy - 1) &&
577 				    (!(lspc & __COLOR) ||
578 				    ((lspc & __COLOR) && __tc_ut))) {
579 					__unsetattr(0);
580 					if (__using_color &&
581 					    ((lspc & __COLOR) !=
582 					    (curscr->wattr & __COLOR)))
583 						__set_color(curscr, lspc &
584 						    __COLOR);
585 					tputs(__tc_ce, 0, __cputchar);
586 					_cursesi_screen->lx = wx + win->begx;
587 					while (wx++ <= clsp) {
588 						csp->ch = ' ';
589 						csp->attr = lspc;
590 						csp++;
591 					}
592 					return (OK);
593 				}
594 				ce = NULL;
595 			}
596 
597 #ifdef DEBUG
598 				__CTRACE("makech: have attributes %08x, need attributes %08x\n", curscr->wattr, nsp->attr);
599 #endif
600 
601 			off = ~nsp->attr & curscr->wattr;
602 
603 			/*
604 			 * Unset attributes as appropriate.  Unset first
605 			 * so that the relevant attributes can be reset
606 			 * (because 'me' unsets 'mb', 'md', 'mh', 'mk',
607 			 * 'mp' and 'mr').  Check to see if we also turn off
608 			 * standout, attributes and colour.
609 			 */
610 			if (off & __TERMATTR && __tc_me != NULL) {
611 				tputs(__tc_me, 0, __cputchar);
612 				curscr->wattr &= __mask_me;
613 				off &= __mask_me;
614 			}
615 
616 			/*
617 			 * Exit underscore mode if appropriate.
618 			 * Check to see if we also turn off standout,
619 			 * attributes and colour.
620 			 */
621 			if (off & __UNDERSCORE && __tc_ue != NULL) {
622 				tputs(__tc_ue, 0, __cputchar);
623 				curscr->wattr &= __mask_ue;
624 				off &= __mask_ue;
625 			}
626 
627 			/*
628 			 * Exit standout mode as appropriate.
629 			 * Check to see if we also turn off underscore,
630 			 * attributes and colour.
631 			 * XXX
632 			 * Should use uc if so/se not available.
633 			 */
634 			if (off & __STANDOUT && __tc_se != NULL) {
635 				tputs(__tc_se, 0, __cputchar);
636 				curscr->wattr &= __mask_se;
637 				off &= __mask_se;
638 			}
639 
640 			if (off & __ALTCHARSET && __tc_ae != NULL) {
641 				tputs(__tc_ae, 0, __cputchar);
642 				curscr->wattr &= ~__ALTCHARSET;
643 			}
644 
645 			/* Set/change colour as appropriate. */
646 			if (__using_color)
647 				__set_color(curscr, nsp->attr & __COLOR);
648 
649 			on = nsp->attr & ~curscr->wattr;
650 
651 			/*
652 			 * Enter standout mode if appropriate.
653 			 */
654 			if (on & __STANDOUT && __tc_so != NULL && __tc_se
655 			    != NULL) {
656 				tputs(__tc_so, 0, __cputchar);
657 				curscr->wattr |= __STANDOUT;
658 			}
659 
660 			/*
661 			 * Enter underscore mode if appropriate.
662 			 * XXX
663 			 * Should use uc if us/ue not available.
664 			 */
665 			if (on & __UNDERSCORE && __tc_us != NULL &&
666 			    __tc_ue != NULL) {
667 				tputs(__tc_us, 0, __cputchar);
668 				curscr->wattr |= __UNDERSCORE;
669 			}
670 
671 			/*
672 			 * Set other attributes as appropriate.
673 			 */
674 			if (__tc_me != NULL) {
675 				if (on & __BLINK && __tc_mb != NULL) {
676 					tputs(__tc_mb, 0, __cputchar);
677 					curscr->wattr |= __BLINK;
678 				}
679 				if (on & __BOLD && __tc_md != NULL) {
680 					tputs(__tc_md, 0, __cputchar);
681 					curscr->wattr |= __BOLD;
682 				}
683 				if (on & __DIM && __tc_mh != NULL) {
684 					tputs(__tc_mh, 0, __cputchar);
685 					curscr->wattr |= __DIM;
686 				}
687 				if (on & __BLANK && __tc_mk != NULL) {
688 					tputs(__tc_mk, 0, __cputchar);
689 					curscr->wattr |= __BLANK;
690 				}
691 				if (on & __PROTECT && __tc_mp != NULL) {
692 					tputs(__tc_mp, 0, __cputchar);
693 					curscr->wattr |= __PROTECT;
694 				}
695 				if (on & __REVERSE && __tc_mr != NULL) {
696 					tputs(__tc_mr, 0, __cputchar);
697 					curscr->wattr |= __REVERSE;
698 				}
699 			}
700 
701 			/* Enter/exit altcharset mode as appropriate. */
702 			if (on & __ALTCHARSET && __tc_as != NULL &&
703 			    __tc_ae != NULL) {
704 				tputs(__tc_as, 0, __cputchar);
705 				curscr->wattr |= __ALTCHARSET;
706 			}
707 
708 			wx++;
709 			if (wx >= win->maxx &&
710 			    wy == win->maxy - 1 && !_cursesi_screen->curwin)
711 				if (win->flags & __SCROLLOK) {
712 					if (win->flags & __ENDLINE)
713 						__unsetattr(1);
714 					if (!(win->flags & __SCROLLWIN)) {
715 						if (!_cursesi_screen->curwin) {
716 							csp->attr = nsp->attr;
717 							__cputchar((int)
718 							    (csp->ch =
719 							    nsp->ch));
720 						} else
721 							__cputchar((int) nsp->ch);
722 					}
723 					if (wx < curscr->maxx) {
724 						domvcur(_cursesi_screen->ly, wx,
725 						    (int) (win->maxy - 1),
726 						    (int) (win->maxx - 1));
727 					}
728 					_cursesi_screen->ly = win->maxy - 1;
729 					_cursesi_screen->lx = win->maxx - 1;
730 					return (OK);
731 				}
732 			if (wx < win->maxx || wy < win->maxy - 1 ||
733 			    !(win->flags & __SCROLLWIN)) {
734 				if (!_cursesi_screen->curwin) {
735 					csp->attr = nsp->attr;
736 					__cputchar((int) (csp->ch = nsp->ch));
737 					csp++;
738 				} else
739 					__cputchar((int) nsp->ch);
740 			}
741 #ifdef DEBUG
742 			__CTRACE("makech: putchar(%c)\n", nsp->ch & 0177);
743 #endif
744 			if (__tc_uc && ((nsp->attr & __STANDOUT) ||
745 			    (nsp->attr & __UNDERSCORE))) {
746 				__cputchar('\b');
747 				tputs(__tc_uc, 0, __cputchar);
748 			}
749 			nsp++;
750 #ifdef DEBUG
751 			__CTRACE("makech: 2: wx = %d, lx = %d\n", wx, _cursesi_screen->lx);
752 #endif
753 		}
754 		if (_cursesi_screen->lx == wx)	/* If no change. */
755 			break;
756 		_cursesi_screen->lx = wx;
757 		if (_cursesi_screen->lx >= COLS && __tc_am)
758 			_cursesi_screen->lx = COLS - 1;
759 		else
760 			if (wx >= win->maxx) {
761 				domvcur(_cursesi_screen->ly,
762 					_cursesi_screen->lx,
763 					_cursesi_screen->ly,
764 					(int) (win->maxx - 1));
765 				_cursesi_screen->lx = win->maxx - 1;
766 			}
767 #ifdef DEBUG
768 		__CTRACE("makech: 3: wx = %d, lx = %d\n", wx,
769 			 _cursesi_screen->lx);
770 #endif
771 	}
772 
773 	return (OK);
774 }
775 
776 /*
777  * domvcur --
778  *	Do a mvcur, leaving attributes if necessary.
779  */
780 static void
781 domvcur(oy, ox, ny, nx)
782 	int	oy, ox, ny, nx;
783 {
784 	__unsetattr(1);
785 	__mvcur(oy, ox, ny, nx, 1);
786 }
787 
788 /*
789  * Quickch() attempts to detect a pattern in the change of the window
790  * in order to optimize the change, e.g., scroll n lines as opposed to
791  * repainting the screen line by line.
792  */
793 
794 static __LDATA buf[128];
795 static  u_int last_hash;
796 static  size_t last_hash_len;
797 #define BLANKSIZE (sizeof(buf) / sizeof(buf[0]))
798 
799 static void
800 quickch(void)
801 {
802 #define THRESH		(int) __virtscr->maxy / 4
803 
804 	__LINE *clp, *tmp1, *tmp2;
805 	int	bsize, curs, curw, starts, startw, i, j;
806 	int	n, target, cur_period, bot, top, sc_region;
807 	u_int	blank_hash;
808 	attr_t	bcolor;
809 
810 #ifdef __GNUC__
811 	curs = curw = starts = startw = 0;	/* XXX gcc -Wuninitialized */
812 #endif
813 	/*
814 	 * Find how many lines from the top of the screen are unchanged.
815 	 */
816 	for (top = 0; top < __virtscr->maxy; top++)
817 		if (__virtscr->lines[top]->flags & __ISDIRTY &&
818 		    (__virtscr->lines[top]->hash != curscr->lines[top]->hash ||
819 		     memcmp(__virtscr->lines[top]->line,
820 			  curscr->lines[top]->line,
821 			  (size_t) __virtscr->maxx * __LDATASIZE) != 0))
822 			break;
823 		else
824 			__virtscr->lines[top]->flags &= ~__ISDIRTY;
825 	/*
826 	 * Find how many lines from bottom of screen are unchanged.
827 	 */
828 	for (bot = __virtscr->maxy - 1; bot >= 0; bot--)
829 		if (__virtscr->lines[bot]->flags & __ISDIRTY &&
830 		    (__virtscr->lines[bot]->hash != curscr->lines[bot]->hash ||
831 		     memcmp(__virtscr->lines[bot]->line,
832 			  curscr->lines[bot]->line,
833 			  (size_t) __virtscr->maxx * __LDATASIZE) != 0))
834 			break;
835 		else
836 			__virtscr->lines[bot]->flags &= ~__ISDIRTY;
837 
838 	/*
839 	 * Work round an xterm bug where inserting lines causes all the
840 	 * inserted lines to be covered with the background colour we
841 	 * set on the first line (even if we unset it for subsequent
842 	 * lines).
843 	 */
844 	bcolor = __virtscr->lines[min(top,
845 	    __virtscr->maxy - 1)]->line[0].attr & __COLOR;
846 	for (i = top + 1, j = 0; i < bot; i++) {
847 		if ((__virtscr->lines[i]->line[0].attr & __COLOR) != bcolor) {
848 			bcolor = __virtscr->lines[i]->line[__virtscr->maxx].
849 			    attr & __COLOR;
850 			j = i - top;
851 		} else
852 			break;
853 	}
854 	top += j;
855 
856 #ifdef NO_JERKINESS
857 	/*
858 	 * If we have a bottom unchanged region return.  Scrolling the
859 	 * bottom region up and then back down causes a screen jitter.
860 	 * This will increase the number of characters sent to the screen
861 	 * but it looks better.
862 	 */
863 	if (bot < __virtscr->maxy - 1)
864 		return;
865 #endif				/* NO_JERKINESS */
866 
867 	/*
868 	 * Search for the largest block of text not changed.
869 	 * Invariants of the loop:
870 	 * - Startw is the index of the beginning of the examined block in
871 	 *   __virtscr.
872 	 * - Starts is the index of the beginning of the examined block in
873 	 *   curscr.
874 	 * - Curw is the index of one past the end of the exmined block in
875 	 *   __virtscr.
876 	 * - Curs is the index of one past the end of the exmined block in
877 	 *   curscr.
878 	 * - bsize is the current size of the examined block.
879 	*/
880 
881 	for (bsize = bot - top; bsize >= THRESH; bsize--) {
882 		for (startw = top; startw <= bot - bsize; startw++)
883 			for (starts = top; starts <= bot - bsize;
884 			    starts++) {
885 				for (curw = startw, curs = starts;
886 				    curs < starts + bsize; curw++, curs++)
887 					if (__virtscr->lines[curw]->hash !=
888 					    curscr->lines[curs]->hash)
889 						break;
890 				if (curs != starts + bsize)
891 					continue;
892 				for (curw = startw, curs = starts;
893 				    curs < starts + bsize; curw++, curs++)
894 					if (memcmp(__virtscr->lines[curw]->line,
895 					    curscr->lines[curs]->line,
896 					    (size_t) __virtscr->maxx *
897 					    __LDATASIZE) != 0)
898 						break;
899 				if (curs == starts + bsize)
900 					goto done;
901 			}
902 	}
903 done:
904 
905 	/* Did not find anything */
906 	if (bsize < THRESH)
907 		return;
908 
909 #ifdef DEBUG
910 	__CTRACE("quickch:bsize=%d,starts=%d,startw=%d,curw=%d,curs=%d,top=%d,bot=%d\n",
911 	    bsize, starts, startw, curw, curs, top, bot);
912 #endif
913 
914 	/*
915 	 * Make sure that there is no overlap between the bottom and top
916 	 * regions and the middle scrolled block.
917 	 */
918 	if (bot < curs)
919 		bot = curs - 1;
920 	if (top > starts)
921 		top = starts;
922 
923 	n = startw - starts;
924 
925 #ifdef DEBUG
926 	__CTRACE("#####################################\n");
927 	for (i = 0; i < curscr->maxy; i++) {
928 		__CTRACE("C: %d:", i);
929 		__CTRACE(" 0x%x \n", curscr->lines[i]->hash);
930 		for (j = 0; j < curscr->maxx; j++)
931 			__CTRACE("%c", curscr->lines[i]->line[j].ch);
932 		__CTRACE("\n");
933 		__CTRACE(" attr:");
934 		for (j = 0; j < curscr->maxx; j++)
935 			__CTRACE(" %x", curscr->lines[i]->line[j].attr);
936 		__CTRACE("\n");
937 		__CTRACE("W: %d:", i);
938 		__CTRACE(" 0x%x \n", __virtscr->lines[i]->hash);
939 		__CTRACE(" 0x%x ", __virtscr->lines[i]->flags);
940 		for (j = 0; j < __virtscr->maxx; j++)
941 			__CTRACE("%c", __virtscr->lines[i]->line[j].ch);
942 		__CTRACE("\n");
943 		__CTRACE(" attr:");
944 		for (j = 0; j < __virtscr->maxx; j++)
945 			__CTRACE(" %x", __virtscr->lines[i]->line[j].attr);
946 		__CTRACE("\n");
947 	}
948 #endif
949 
950 	if (buf[0].ch != ' ') {
951 		for (i = 0; i < BLANKSIZE; i++) {
952 			buf[i].ch = ' ';
953 			buf[i].bch = ' ';
954 			buf[i].attr = 0;
955 			buf[i].battr = 0;
956 		}
957 	}
958 
959 	if (__virtscr->maxx != last_hash_len) {
960 		blank_hash = 0;
961 		for (i = __virtscr->maxx; i > BLANKSIZE; i -= BLANKSIZE) {
962 			blank_hash = __hash_more((char *)(void *)buf, sizeof(buf),
963 			    blank_hash);
964 		}
965 		blank_hash = __hash_more((char *)(void *)buf,
966 		    i * sizeof(buf[0]), blank_hash);
967 		/* cache result in static data - screen width doesn't change often */
968 		last_hash_len = __virtscr->maxx;
969 		last_hash = blank_hash;
970 	} else
971 		blank_hash = last_hash;
972 
973 	/*
974 	 * Perform the rotation to maintain the consistency of curscr.
975 	 * This is hairy since we are doing an *in place* rotation.
976 	 * Invariants of the loop:
977 	 * - I is the index of the current line.
978 	 * - Target is the index of the target of line i.
979 	 * - Tmp1 points to current line (i).
980 	 * - Tmp2 and points to target line (target);
981 	 * - Cur_period is the index of the end of the current period.
982 	 *   (see below).
983 	 *
984 	 * There are 2 major issues here that make this rotation non-trivial:
985 	 * 1.  Scrolling in a scrolling region bounded by the top
986 	 *     and bottom regions determined (whose size is sc_region).
987 	 * 2.  As a result of the use of the mod function, there may be a
988 	 *     period introduced, i.e., 2 maps to 4, 4 to 6, n-2 to 0, and
989 	 *     0 to 2, which then causes all odd lines not to be rotated.
990 	 *     To remedy this, an index of the end ( = beginning) of the
991 	 *     current 'period' is kept, cur_period, and when it is reached,
992 	 *     the next period is started from cur_period + 1 which is
993 	 *     guaranteed not to have been reached since that would mean that
994 	 *     all records would have been reached. (think about it...).
995 	 *
996 	 * Lines in the rotation can have 3 attributes which are marked on the
997 	 * line so that curscr is consistent with the visual screen.
998 	 * 1.  Not dirty -- lines inside the scrolled block, top region or
999 	 *                  bottom region.
1000 	 * 2.  Blank lines -- lines in the differential of the scrolling
1001 	 *		      region adjacent to top and bot regions
1002 	 *                    depending on scrolling direction.
1003 	 * 3.  Dirty line -- all other lines are marked dirty.
1004 	 */
1005 	sc_region = bot - top + 1;
1006 	i = top;
1007 	tmp1 = curscr->lines[top];
1008 	cur_period = top;
1009 	for (j = top; j <= bot; j++) {
1010 		target = (i - top + n + sc_region) % sc_region + top;
1011 		tmp2 = curscr->lines[target];
1012 		curscr->lines[target] = tmp1;
1013 		/* Mark block as clean and blank out scrolled lines. */
1014 		clp = curscr->lines[target];
1015 #ifdef DEBUG
1016 		__CTRACE("quickch: n=%d startw=%d curw=%d i = %d target=%d ",
1017 		    n, startw, curw, i, target);
1018 #endif
1019 		if ((target >= startw && target < curw) || target < top
1020 		    || target > bot) {
1021 #ifdef DEBUG
1022 			__CTRACE("-- notdirty\n");
1023 #endif
1024 			__virtscr->lines[target]->flags &= ~__ISDIRTY;
1025 		} else
1026 			if ((n > 0 && target >= top && target < top + n) ||
1027 			    (n < 0 && target <= bot && target > bot + n)) {
1028 				if (clp->hash != blank_hash || memcmp(clp->line,
1029 				    clp->line + 1, (__virtscr->maxx - 1) *
1030 				    __LDATASIZE) || memcmp(clp->line, buf,
1031 				    __LDATASIZE)) {
1032 					for (i = __virtscr->maxx; i > BLANKSIZE;
1033 					    i -= BLANKSIZE) {
1034 						(void)memcpy(clp->line + i -
1035 						    BLANKSIZE, buf, sizeof(buf));
1036 					}
1037 					(void)memcpy(clp->line , buf, i *
1038 					    sizeof(buf[0]));
1039 #ifdef DEBUG
1040 					__CTRACE("-- blanked out: dirty\n");
1041 #endif
1042 					clp->hash = blank_hash;
1043 					__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
1044 				} else {
1045 #ifdef DEBUG
1046 					__CTRACE(" -- blank line already: dirty\n");
1047 #endif
1048 					__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
1049 				}
1050 			} else {
1051 #ifdef DEBUG
1052 				__CTRACE(" -- dirty\n");
1053 #endif
1054 				__touchline(__virtscr, target, 0, (int) __virtscr->maxx - 1);
1055 			}
1056 		if (target == cur_period) {
1057 			i = target + 1;
1058 			tmp1 = curscr->lines[i];
1059 			cur_period = i;
1060 		} else {
1061 			tmp1 = tmp2;
1062 			i = target;
1063 		}
1064 	}
1065 #ifdef DEBUG
1066 	__CTRACE("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$\n");
1067 	for (i = 0; i < curscr->maxy; i++) {
1068 		__CTRACE("C: %d:", i);
1069 		for (j = 0; j < curscr->maxx; j++)
1070 			__CTRACE("%c", curscr->lines[i]->line[j].ch);
1071 		__CTRACE("\n");
1072 		__CTRACE("W: %d:", i);
1073 		for (j = 0; j < __virtscr->maxx; j++)
1074 			__CTRACE("%c", __virtscr->lines[i]->line[j].ch);
1075 		__CTRACE("\n");
1076 	}
1077 #endif
1078 	if (n != 0)
1079 		scrolln(starts, startw, curs, bot, top);
1080 }
1081 
1082 /*
1083  * scrolln --
1084  *	Scroll n lines, where n is starts - startw.
1085  */
1086 static void /* ARGSUSED */
1087 scrolln(starts, startw, curs, bot, top)
1088 	int	starts, startw, curs, bot, top;
1089 {
1090 	int	i, oy, ox, n;
1091 
1092 	oy = curscr->cury;
1093 	ox = curscr->curx;
1094 	n = starts - startw;
1095 
1096 	/*
1097 	 * XXX
1098 	 * The initial tests that set __noqch don't let us reach here unless
1099 	 * we have either cs + ho + SF/sf/SR/sr, or AL + DL.  SF/sf and SR/sr
1100 	 * scrolling can only shift the entire scrolling region, not just a
1101 	 * part of it, which means that the quickch() routine is going to be
1102 	 * sadly disappointed in us if we don't have cs as well.
1103 	 *
1104 	 * If cs, ho and SF/sf are set, can use the scrolling region.  Because
1105 	 * the cursor position after cs is undefined, we need ho which gives us
1106 	 * the ability to move to somewhere without knowledge of the current
1107 	 * location of the cursor.  Still call __mvcur() anyway, to update its
1108 	 * idea of where the cursor is.
1109 	 *
1110 	 * When the scrolling region has been set, the cursor has to be at the
1111 	 * last line of the region to make the scroll happen.
1112 	 *
1113 	 * Doing SF/SR or AL/DL appears faster on the screen than either sf/sr
1114 	 * or AL/DL, and, some terminals have AL/DL, sf/sr, and cs, but not
1115 	 * SF/SR.  So, if we're scrolling almost all of the screen, try and use
1116 	 * AL/DL, otherwise use the scrolling region.  The "almost all" is a
1117 	 * shameless hack for vi.
1118 	 */
1119 	if (n > 0) {
1120 		if (__tc_cs != NULL && __tc_ho != NULL && (__tc_SF != NULL ||
1121 		    ((__tc_AL == NULL || __tc_DL == NULL ||
1122 		    top > 3 || bot + 3 < __virtscr->maxy) &&
1123 		    __tc_sf != NULL))) {
1124 			tputs(__tscroll(__tc_cs, top, bot + 1), 0, __cputchar);
1125 			__mvcur(oy, ox, 0, 0, 1);
1126 			tputs(__tc_ho, 0, __cputchar);
1127 			__mvcur(0, 0, bot, 0, 1);
1128 			if (__tc_SF != NULL)
1129 				tputs(__tscroll(__tc_SF, n, 0), 0, __cputchar);
1130 			else
1131 				for (i = 0; i < n; i++)
1132 					tputs(__tc_sf, 0, __cputchar);
1133 			tputs(__tscroll(__tc_cs, 0, (int) __virtscr->maxy), 0,
1134 			    __cputchar);
1135 			__mvcur(bot, 0, 0, 0, 1);
1136 			tputs(__tc_ho, 0, __cputchar);
1137 			__mvcur(0, 0, oy, ox, 1);
1138 			return;
1139 		}
1140 
1141 		/* Scroll up the block. */
1142 		if (__tc_SF != NULL && top == 0) {
1143 			__mvcur(oy, ox, bot, 0, 1);
1144 			tputs(__tscroll(__tc_SF, n, 0), 0, __cputchar);
1145 		} else
1146 			if (__tc_DL != NULL) {
1147 				__mvcur(oy, ox, top, 0, 1);
1148 				tputs(__tscroll(__tc_DL, n, 0), 0, __cputchar);
1149 			} else
1150 				if (__tc_dl != NULL) {
1151 					__mvcur(oy, ox, top, 0, 1);
1152 					for (i = 0; i < n; i++)
1153 						tputs(__tc_dl, 0, __cputchar);
1154 				} else
1155 					if (__tc_sf != NULL && top == 0) {
1156 						__mvcur(oy, ox, bot, 0, 1);
1157 						for (i = 0; i < n; i++)
1158 							tputs(__tc_sf, 0,
1159 							    __cputchar);
1160 					} else
1161 						abort();
1162 
1163 		/* Push down the bottom region. */
1164 		__mvcur(top, 0, bot - n + 1, 0, 1);
1165 		if (__tc_AL != NULL)
1166 			tputs(__tscroll(__tc_AL, n, 0), 0, __cputchar);
1167 		else
1168 			if (__tc_al != NULL)
1169 				for (i = 0; i < n; i++)
1170 					tputs(__tc_al, 0, __cputchar);
1171 			else
1172 				abort();
1173 		__mvcur(bot - n + 1, 0, oy, ox, 1);
1174 	} else {
1175 		/*
1176 		 * !!!
1177 		 * n < 0
1178 		 *
1179 		 * If cs, ho and SR/sr are set, can use the scrolling region.
1180 		 * See the above comments for details.
1181 		 */
1182 		if (__tc_cs != NULL && __tc_ho != NULL && (__tc_SR != NULL ||
1183 		    ((__tc_AL == NULL || __tc_DL == NULL || top > 3 ||
1184 		    bot + 3 < __virtscr->maxy) && __tc_sr != NULL))) {
1185 			tputs(__tscroll(__tc_cs, top, bot + 1), 0, __cputchar);
1186 			__mvcur(oy, ox, 0, 0, 1);
1187 			tputs(__tc_ho, 0, __cputchar);
1188 			__mvcur(0, 0, top, 0, 1);
1189 
1190 			if (__tc_SR != NULL)
1191 				tputs(__tscroll(__tc_SR, -n, 0), 0, __cputchar);
1192 			else
1193 				for (i = n; i < 0; i++)
1194 					tputs(__tc_sr, 0, __cputchar);
1195 			tputs(__tscroll(__tc_cs, 0, (int) __virtscr->maxy), 0,
1196 			    __cputchar);
1197 			__mvcur(top, 0, 0, 0, 1);
1198 			tputs(__tc_ho, 0, __cputchar);
1199 			__mvcur(0, 0, oy, ox, 1);
1200 			return;
1201 		}
1202 
1203 		/* Preserve the bottom lines. */
1204 		__mvcur(oy, ox, bot + n + 1, 0, 1);
1205 		if (__tc_SR != NULL && bot == __virtscr->maxy)
1206 			tputs(__tscroll(__tc_SR, -n, 0), 0, __cputchar);
1207 		else
1208 			if (__tc_DL != NULL)
1209 				tputs(__tscroll(__tc_DL, -n, 0), 0, __cputchar);
1210 			else
1211 				if (__tc_dl != NULL)
1212 					for (i = n; i < 0; i++)
1213 						tputs(__tc_dl, 0, __cputchar);
1214 				else
1215 					if (__tc_sr != NULL &&
1216 					    bot == __virtscr->maxy)
1217 						for (i = n; i < 0; i++)
1218 							tputs(__tc_sr, 0,
1219 							    __cputchar);
1220 					else
1221 						abort();
1222 
1223 		/* Scroll the block down. */
1224 		__mvcur(bot + n + 1, 0, top, 0, 1);
1225 		if (__tc_AL != NULL)
1226 			tputs(__tscroll(__tc_AL, -n, 0), 0, __cputchar);
1227 		else
1228 			if (__tc_al != NULL)
1229 				for (i = n; i < 0; i++)
1230 					tputs(__tc_al, 0, __cputchar);
1231 			else
1232 				abort();
1233 		__mvcur(top, 0, oy, ox, 1);
1234 	}
1235 }
1236 
1237 /*
1238  * __unsetattr --
1239  *	Unset attributes on curscr.  Leave standout, attribute and colour
1240  *	modes if necessary (!ms).  Always leave altcharset (xterm at least
1241  *	ignores a cursor move if we don't).
1242  */
1243 void /* ARGSUSED */
1244 __unsetattr(int checkms)
1245 {
1246 	int	isms;
1247 
1248 	if (checkms)
1249 		if (!__tc_ms) {
1250 			isms = 1;
1251 		} else {
1252 			isms = 0;
1253 		}
1254 	else
1255 		isms = 1;
1256 #ifdef DEBUG
1257 	__CTRACE("__unsetattr: checkms = %d, ms = %s, wattr = %08x\n",
1258 	    checkms, __tc_ms ? "TRUE" : "FALSE", curscr->wattr);
1259 #endif
1260 
1261 	/*
1262          * Don't leave the screen in standout mode (check against ms).  Check
1263 	 * to see if we also turn off underscore, attributes and colour.
1264 	 */
1265 	if (curscr->wattr & __STANDOUT && isms) {
1266 		tputs(__tc_se, 0, __cputchar);
1267 		curscr->wattr &= __mask_se;
1268 	}
1269 	/*
1270 	 * Don't leave the screen in underscore mode (check against ms).
1271 	 * Check to see if we also turn off attributes.  Assume that we
1272 	 * also turn off colour.
1273 	 */
1274 	if (curscr->wattr & __UNDERSCORE && isms) {
1275 		tputs(__tc_ue, 0, __cputchar);
1276 		curscr->wattr &= __mask_ue;
1277 	}
1278 	/*
1279 	 * Don't leave the screen with attributes set (check against ms).
1280 	 * Assume that also turn off colour.
1281 	 */
1282 	if (curscr->wattr & __TERMATTR && isms) {
1283 		tputs(__tc_me, 0, __cputchar);
1284 		curscr->wattr &= __mask_me;
1285 	}
1286 	/* Don't leave the screen with altcharset set (don't check ms). */
1287 	if (curscr->wattr & __ALTCHARSET) {
1288 		tputs(__tc_ae, 0, __cputchar);
1289 		curscr->wattr &= ~__ALTCHARSET;
1290 	}
1291 	/* Don't leave the screen with colour set (check against ms). */
1292 	if (__using_color && isms)
1293 		__unset_color(curscr);
1294 }
1295