xref: /freebsd/contrib/nvi/vi/vs_split.c (revision 110d525ec6188f3c9dc4f54c4bc1cced2f7184cd)
1  /*-
2   * Copyright (c) 1993, 1994
3   *	The Regents of the University of California.  All rights reserved.
4   * Copyright (c) 1993, 1994, 1995, 1996
5   *	Keith Bostic.  All rights reserved.
6   *
7   * See the LICENSE file for redistribution information.
8   */
9  
10  #include "config.h"
11  
12  #include <sys/types.h>
13  #include <sys/queue.h>
14  #include <sys/time.h>
15  
16  #include <bitstring.h>
17  #include <errno.h>
18  #include <limits.h>
19  #include <stdio.h>
20  #include <stdlib.h>
21  #include <string.h>
22  
23  #include "../common/common.h"
24  #include "vi.h"
25  
26  typedef enum { HORIZ_FOLLOW, HORIZ_PRECEDE, VERT_FOLLOW, VERT_PRECEDE } jdir_t;
27  
28  static SCR	*vs_getbg(SCR *, char *);
29  static void      vs_insert(SCR *sp, GS *gp);
30  static int	 vs_join(SCR *, SCR **, jdir_t *);
31  
32  /*
33   * vs_split --
34   *	Create a new screen, horizontally.
35   *
36   * PUBLIC: int vs_split(SCR *, SCR *, int);
37   */
38  int
vs_split(SCR * sp,SCR * new,int ccl)39  vs_split(
40  	SCR *sp,
41  	SCR *new,
42  	int ccl)		/* Colon-command line split. */
43  {
44  	GS *gp;
45  	SMAP *smp;
46  	size_t half;
47  	int issmallscreen, splitup;
48  
49  	gp = sp->gp;
50  
51  	/* Check to see if it's possible. */
52  	/* XXX: The IS_ONELINE fix will change this, too. */
53  	if (sp->rows < 4) {
54  		msgq(sp, M_ERR,
55  		    "222|Screen must be larger than %d lines to split", 4 - 1);
56  		return (1);
57  	}
58  
59  	/* Wait for any messages in the screen. */
60  	vs_resolve(sp, NULL, 1);
61  
62  	/* Get a new screen map. */
63  	CALLOC(sp, _HMAP(new), SIZE_HMAP(sp), sizeof(SMAP));
64  	if (_HMAP(new) == NULL)
65  		return (1);
66  	_HMAP(new)->lno = sp->lno;
67  	_HMAP(new)->coff = 0;
68  	_HMAP(new)->soff = 1;
69  
70  	/* Split the screen in half. */
71  	half = sp->rows / 2;
72  	if (ccl && half > 6)
73  		half = 6;
74  
75  	/*
76  	 * Small screens: see vs_refresh.c section 6a.  Set a flag so
77  	 * we know to fix the screen up later.
78  	 */
79  	issmallscreen = IS_SMALL(sp);
80  
81  	/* The columns in the screen don't change. */
82  	new->coff = sp->coff;
83  	new->cols = sp->cols;
84  
85  	/*
86  	 * Split the screen, and link the screens together.  If creating a
87  	 * screen to edit the colon command line or the cursor is in the top
88  	 * half of the current screen, the new screen goes under the current
89  	 * screen.  Else, it goes above the current screen.
90  	 *
91  	 * Recalculate current cursor position based on sp->lno, we're called
92  	 * with the cursor on the colon command line.  Then split the screen
93  	 * in half and update the shared information.
94  	 */
95  	splitup =
96  	    !ccl && (vs_sm_cursor(sp, &smp) ? 0 : (smp - HMAP) + 1) >= half;
97  	if (splitup) {				/* Old is bottom half. */
98  		new->rows = sp->rows - half;	/* New. */
99  		new->roff = sp->roff;
100  		sp->rows = half;		/* Old. */
101  		sp->roff += new->rows;
102  
103  		/*
104  		 * If the parent is the bottom half of the screen, shift
105  		 * the map down to match on-screen text.
106  		 */
107  		memcpy(_HMAP(sp), _HMAP(sp) + new->rows,
108  		    (sp->t_maxrows - new->rows) * sizeof(SMAP));
109  	} else {				/* Old is top half. */
110  		new->rows = half;		/* New. */
111  		sp->rows -= half;		/* Old. */
112  		new->roff = sp->roff + sp->rows;
113  	}
114  
115  	/* Adjust maximum text count. */
116  	sp->t_maxrows = IS_ONELINE(sp) ? 1 : sp->rows - 1;
117  	new->t_maxrows = IS_ONELINE(new) ? 1 : new->rows - 1;
118  
119  	/*
120  	 * Small screens: see vs_refresh.c, section 6a.
121  	 *
122  	 * The child may have different screen options sizes than the parent,
123  	 * so use them.  Guarantee that text counts aren't larger than the
124  	 * new screen sizes.
125  	 */
126  	if (issmallscreen) {
127  		/* Fix the text line count for the parent. */
128  		if (splitup)
129  			sp->t_rows -= new->rows;
130  
131  		/* Fix the parent screen. */
132  		if (sp->t_rows > sp->t_maxrows)
133  			sp->t_rows = sp->t_maxrows;
134  		if (sp->t_minrows > sp->t_maxrows)
135  			sp->t_minrows = sp->t_maxrows;
136  
137  		/* Fix the child screen. */
138  		new->t_minrows = new->t_rows = O_VAL(sp, O_WINDOW);
139  		if (new->t_rows > new->t_maxrows)
140  			new->t_rows = new->t_maxrows;
141  		if (new->t_minrows > new->t_maxrows)
142  			new->t_minrows = new->t_maxrows;
143  	} else {
144  		sp->t_minrows = sp->t_rows = IS_ONELINE(sp) ? 1 : sp->rows - 1;
145  
146  		/*
147  		 * The new screen may be a small screen, even if the parent
148  		 * was not.  Don't complain if O_WINDOW is too large, we're
149  		 * splitting the screen so the screen is much smaller than
150  		 * normal.
151  		 */
152  		new->t_minrows = new->t_rows = O_VAL(sp, O_WINDOW);
153  		if (new->t_rows > new->rows - 1)
154  			new->t_minrows = new->t_rows =
155  			    IS_ONELINE(new) ? 1 : new->rows - 1;
156  	}
157  
158  	/* Adjust the ends of the new and old maps. */
159  	_TMAP(sp) = IS_ONELINE(sp) ?
160  	    _HMAP(sp) : _HMAP(sp) + (sp->t_rows - 1);
161  	_TMAP(new) = IS_ONELINE(new) ?
162  	    _HMAP(new) : _HMAP(new) + (new->t_rows - 1);
163  
164  	/* Reset the length of the default scroll. */
165  	if ((sp->defscroll = sp->t_maxrows / 2) == 0)
166  		sp->defscroll = 1;
167  	if ((new->defscroll = new->t_maxrows / 2) == 0)
168  		new->defscroll = 1;
169  
170  	/* Fit the screen into the logical chain. */
171  	vs_insert(new, sp->gp);
172  
173  	/* Tell the display that we're splitting. */
174  	(void)gp->scr_split(sp, new);
175  
176  	/*
177  	 * Initialize the screen flags:
178  	 *
179  	 * If we're in vi mode in one screen, we don't have to reinitialize.
180  	 * This isn't just a cosmetic fix.  The path goes like this:
181  	 *
182  	 *	return into vi(), SC_SSWITCH set
183  	 *	call vs_refresh() with SC_STATUS set
184  	 *	call vs_resolve to display the status message
185  	 *	call vs_refresh() because the SC_SCR_VI bit isn't set
186  	 *
187  	 * Things go downhill at this point.
188  	 *
189  	 * Draw the new screen from scratch, and add a status line.
190  	 */
191  	F_SET(new,
192  	    SC_SCR_REFORMAT | SC_STATUS |
193  	    F_ISSET(sp, SC_EX | SC_VI | SC_SCR_VI | SC_SCR_EX | SC_READONLY));
194  	return (0);
195  }
196  
197  /*
198   * vs_vsplit --
199   *	Create a new screen, vertically.
200   *
201   * PUBLIC: int vs_vsplit(SCR *, SCR *);
202   */
203  int
vs_vsplit(SCR * sp,SCR * new)204  vs_vsplit(SCR *sp, SCR *new)
205  {
206  	GS *gp;
207  	size_t cols;
208  
209  	gp = sp->gp;
210  
211  	/* Check to see if it's possible. */
212  	if (sp->cols / 2 <= MINIMUM_SCREEN_COLS) {
213  		msgq(sp, M_ERR,
214  		    "288|Screen must be larger than %d columns to split",
215  		    MINIMUM_SCREEN_COLS * 2);
216  		return (1);
217  	}
218  
219  	/* Wait for any messages in the screen. */
220  	vs_resolve(sp, NULL, 1);
221  
222  	/* Get a new screen map. */
223  	CALLOC(sp, _HMAP(new), SIZE_HMAP(sp), sizeof(SMAP));
224  	if (_HMAP(new) == NULL)
225  		return (1);
226  	_HMAP(new)->lno = sp->lno;
227  	_HMAP(new)->coff = 0;
228  	_HMAP(new)->soff = 1;
229  
230  	/*
231  	 * Split the screen in half; we have to sacrifice a column to delimit
232  	 * the screens.
233  	 *
234  	 * XXX
235  	 * We always split to the right... that makes more sense to me, and
236  	 * I don't want to play the stupid games that I play when splitting
237  	 * horizontally.
238  	 *
239  	 * XXX
240  	 * We reserve a column for the screen, "knowing" that curses needs
241  	 * one.  This should be worked out with the display interface.
242  	 */
243  	cols = sp->cols / 2;
244  	new->cols = sp->cols - cols - 1;
245  	sp->cols = cols;
246  	new->coff = sp->coff + cols + 1;
247  	sp->cno = 0;
248  
249  	/* Nothing else changes. */
250  	new->rows = sp->rows;
251  	new->t_rows = sp->t_rows;
252  	new->t_maxrows = sp->t_maxrows;
253  	new->t_minrows = sp->t_minrows;
254  	new->roff = sp->roff;
255  	new->defscroll = sp->defscroll;
256  	_TMAP(new) = _HMAP(new) + (new->t_rows - 1);
257  
258  	/* Fit the screen into the logical chain. */
259  	vs_insert(new, sp->gp);
260  
261  	/* Tell the display that we're splitting. */
262  	(void)gp->scr_split(sp, new);
263  
264  	/* Redraw the old screen from scratch. */
265  	F_SET(sp, SC_SCR_REFORMAT | SC_STATUS);
266  
267  	/*
268  	 * Initialize the screen flags:
269  	 *
270  	 * If we're in vi mode in one screen, we don't have to reinitialize.
271  	 * This isn't just a cosmetic fix.  The path goes like this:
272  	 *
273  	 *	return into vi(), SC_SSWITCH set
274  	 *	call vs_refresh() with SC_STATUS set
275  	 *	call vs_resolve to display the status message
276  	 *	call vs_refresh() because the SC_SCR_VI bit isn't set
277  	 *
278  	 * Things go downhill at this point.
279  	 *
280  	 * Draw the new screen from scratch, and add a status line.
281  	 */
282  	F_SET(new,
283  	    SC_SCR_REFORMAT | SC_STATUS |
284  	    F_ISSET(sp, SC_EX | SC_VI | SC_SCR_VI | SC_SCR_EX | SC_READONLY));
285  	return (0);
286  }
287  
288  /*
289   * vs_insert --
290   *	Insert the new screen into the correct place in the logical
291   *	chain.
292   */
293  static void
vs_insert(SCR * sp,GS * gp)294  vs_insert(SCR *sp, GS *gp)
295  {
296  	SCR *tsp;
297  
298  	gp = sp->gp;
299  
300  	/* Move past all screens with lower row numbers. */
301  	TAILQ_FOREACH(tsp, gp->dq, q)
302  		if (tsp->roff >= sp->roff)
303  			break;
304  	/*
305  	 * Move past all screens with the same row number and lower
306  	 * column numbers.
307  	 */
308  	for (; tsp != NULL; tsp = TAILQ_NEXT(tsp, q))
309  		if (tsp->roff != sp->roff || tsp->coff > sp->coff)
310  			break;
311  
312  	/*
313  	 * If we reached the end, this screen goes there.  Otherwise,
314  	 * put it before or after the screen where we stopped.
315  	 */
316  	if (tsp == NULL) {
317  		TAILQ_INSERT_TAIL(gp->dq, sp, q);
318  	} else if (tsp->roff < sp->roff ||
319  	    (tsp->roff == sp->roff && tsp->coff < sp->coff)) {
320  		TAILQ_INSERT_AFTER(gp->dq, tsp, sp, q);
321  	} else
322  		TAILQ_INSERT_BEFORE(tsp, sp, q);
323  }
324  
325  /*
326   * vs_discard --
327   *	Discard the screen, folding the real-estate into a related screen,
328   *	if one exists, and return that screen.
329   *
330   * PUBLIC: int vs_discard(SCR *, SCR **);
331   */
332  int
vs_discard(SCR * sp,SCR ** spp)333  vs_discard(SCR *sp, SCR **spp)
334  {
335  	GS *gp;
336  	SCR *tsp, **lp, *list[100];
337  	jdir_t jdir;
338  
339  	gp = sp->gp;
340  
341  	/*
342  	 * Save the old screen's cursor information.
343  	 *
344  	 * XXX
345  	 * If called after file_end(), and the underlying file was a tmp
346  	 * file, it may have gone away.
347  	 */
348  	if (sp->frp != NULL) {
349  		sp->frp->lno = sp->lno;
350  		sp->frp->cno = sp->cno;
351  		F_SET(sp->frp, FR_CURSORSET);
352  	}
353  
354  	/* If no other screens to join, we're done. */
355  	if (!IS_SPLIT(sp)) {
356  		(void)gp->scr_discard(sp, NULL);
357  
358  		if (spp != NULL)
359  			*spp = NULL;
360  		return (0);
361  	}
362  
363  	/*
364  	 * Find a set of screens that cover one of the screen's borders.
365  	 * Check the vertical axis first, for no particular reason.
366  	 *
367  	 * XXX
368  	 * It's possible (I think?), to create a screen that shares no full
369  	 * border with any other set of screens, so we can't discard it.  We
370  	 * just complain at the user until they clean it up.
371  	 */
372  	if (vs_join(sp, list, &jdir))
373  		return (1);
374  
375  	/*
376  	 * Modify the affected screens.  Redraw the modified screen(s) from
377  	 * scratch, setting a status line.  If this is ever a performance
378  	 * problem we could play games with the map, but I wrote that code
379  	 * before and it was never clean or easy.
380  	 *
381  	 * Don't clean up the discarded screen's information.  If the screen
382  	 * isn't exiting, we'll do the work when the user redisplays it.
383  	 */
384  	switch (jdir) {
385  	case HORIZ_FOLLOW:
386  	case HORIZ_PRECEDE:
387  		for (lp = &list[0]; (tsp = *lp) != NULL; ++lp) {
388  			/*
389  			 * Small screens: see vs_refresh.c section 6a.  Adjust
390  			 * text line info, unless it's a small screen.
391  			 *
392  			 * Reset the length of the default scroll.
393  			 *
394  			 * Reset the map references.
395  			 */
396  			tsp->rows += sp->rows;
397  			if (!IS_SMALL(tsp))
398  				tsp->t_rows = tsp->t_minrows = tsp->rows - 1;
399  			tsp->t_maxrows = tsp->rows - 1;
400  
401  			tsp->defscroll = tsp->t_maxrows / 2;
402  
403  			*(_HMAP(tsp) + (tsp->t_rows - 1)) = *_TMAP(tsp);
404  			_TMAP(tsp) = _HMAP(tsp) + (tsp->t_rows - 1);
405  
406  			switch (jdir) {
407  			case HORIZ_FOLLOW:
408  				tsp->roff = sp->roff;
409  				vs_sm_fill(tsp, OOBLNO, P_TOP);
410  				break;
411  			case HORIZ_PRECEDE:
412  				vs_sm_fill(tsp, OOBLNO, P_BOTTOM);
413  				break;
414  			default:
415  				abort();
416  			}
417  			F_SET(tsp, SC_STATUS);
418  		}
419  		break;
420  	case VERT_FOLLOW:
421  	case VERT_PRECEDE:
422  		for (lp = &list[0]; (tsp = *lp) != NULL; ++lp) {
423  			if (jdir == VERT_FOLLOW)
424  				tsp->coff = sp->coff;
425  			tsp->cols += sp->cols + 1;	/* XXX: DIVIDER */
426  			vs_sm_fill(tsp, OOBLNO, P_TOP);
427  			F_SET(tsp, SC_STATUS);
428  		}
429  		break;
430  	default:
431  		abort();
432  	}
433  
434  	/* Find the closest screen that changed and move to it. */
435  	tsp = list[0];
436  	if (spp != NULL)
437  		*spp = tsp;
438  
439  	/* Tell the display that we're discarding a screen. */
440  	(void)gp->scr_discard(sp, list);
441  
442  	return (0);
443  }
444  
445  /*
446   * vs_join --
447   *	Find a set of screens that covers a screen's border.
448   */
449  static int
vs_join(SCR * sp,SCR ** listp,jdir_t * jdirp)450  vs_join(SCR *sp, SCR **listp, jdir_t *jdirp)
451  {
452  	GS *gp;
453  	SCR **lp, *tsp;
454  	int first;
455  	size_t tlen;
456  
457  	gp = sp->gp;
458  
459  	/* Check preceding vertical. */
460  	for (lp = listp, tlen = sp->rows,
461  	    tsp = TAILQ_FIRST(gp->dq);
462  	    tsp != NULL; tsp = TAILQ_NEXT(tsp, q)) {
463  		if (sp == tsp)
464  			continue;
465  		/* Test if precedes the screen vertically. */
466  		if (tsp->coff + tsp->cols + 1 != sp->coff)
467  			continue;
468  		/*
469  		 * Test if a subset on the vertical axis.  If overlaps the
470  		 * beginning or end, we can't join on this axis at all.
471  		 */
472  		if (tsp->roff > sp->roff + sp->rows)
473  			continue;
474  		if (tsp->roff < sp->roff) {
475  			if (tsp->roff + tsp->rows >= sp->roff)
476  				break;
477  			continue;
478  		}
479  		if (tsp->roff + tsp->rows > sp->roff + sp->rows)
480  			break;
481  #ifdef DEBUG
482  		if (tlen < tsp->rows)
483  			abort();
484  #endif
485  		tlen -= tsp->rows;
486  		*lp++ = tsp;
487  	}
488  	if (tlen == 0) {
489  		*lp = NULL;
490  		*jdirp = VERT_PRECEDE;
491  		return (0);
492  	}
493  
494  	/* Check following vertical. */
495  	for (lp = listp, tlen = sp->rows,
496  	    tsp = TAILQ_FIRST(gp->dq);
497  	    tsp != NULL; tsp = TAILQ_NEXT(tsp, q)) {
498  		if (sp == tsp)
499  			continue;
500  		/* Test if follows the screen vertically. */
501  		if (tsp->coff != sp->coff + sp->cols + 1)
502  			continue;
503  		/*
504  		 * Test if a subset on the vertical axis.  If overlaps the
505  		 * beginning or end, we can't join on this axis at all.
506  		 */
507  		if (tsp->roff > sp->roff + sp->rows)
508  			continue;
509  		if (tsp->roff < sp->roff) {
510  			if (tsp->roff + tsp->rows >= sp->roff)
511  				break;
512  			continue;
513  		}
514  		if (tsp->roff + tsp->rows > sp->roff + sp->rows)
515  			break;
516  #ifdef DEBUG
517  		if (tlen < tsp->rows)
518  			abort();
519  #endif
520  		tlen -= tsp->rows;
521  		*lp++ = tsp;
522  	}
523  	if (tlen == 0) {
524  		*lp = NULL;
525  		*jdirp = VERT_FOLLOW;
526  		return (0);
527  	}
528  
529  	/* Check preceding horizontal. */
530  	for (first = 0, lp = listp, tlen = sp->cols,
531  	    tsp = TAILQ_FIRST(gp->dq);
532  	    tsp != NULL; tsp = TAILQ_NEXT(tsp, q)) {
533  		if (sp == tsp)
534  			continue;
535  		/* Test if precedes the screen horizontally. */
536  		if (tsp->roff + tsp->rows != sp->roff)
537  			continue;
538  		/*
539  		 * Test if a subset on the horizontal axis.  If overlaps the
540  		 * beginning or end, we can't join on this axis at all.
541  		 */
542  		if (tsp->coff > sp->coff + sp->cols)
543  			continue;
544  		if (tsp->coff < sp->coff) {
545  			if (tsp->coff + tsp->cols >= sp->coff)
546  				break;
547  			continue;
548  		}
549  		if (tsp->coff + tsp->cols > sp->coff + sp->cols)
550  			break;
551  #ifdef DEBUG
552  		if (tlen < tsp->cols)
553  			abort();
554  #endif
555  		tlen -= tsp->cols + first;
556  		first = 1;
557  		*lp++ = tsp;
558  	}
559  	if (tlen == 0) {
560  		*lp = NULL;
561  		*jdirp = HORIZ_PRECEDE;
562  		return (0);
563  	}
564  
565  	/* Check following horizontal. */
566  	for (first = 0, lp = listp, tlen = sp->cols,
567  	    tsp = TAILQ_FIRST(gp->dq);
568  	    tsp != NULL; tsp = TAILQ_NEXT(tsp, q)) {
569  		if (sp == tsp)
570  			continue;
571  		/* Test if precedes the screen horizontally. */
572  		if (tsp->roff != sp->roff + sp->rows)
573  			continue;
574  		/*
575  		 * Test if a subset on the horizontal axis.  If overlaps the
576  		 * beginning or end, we can't join on this axis at all.
577  		 */
578  		if (tsp->coff > sp->coff + sp->cols)
579  			continue;
580  		if (tsp->coff < sp->coff) {
581  			if (tsp->coff + tsp->cols >= sp->coff)
582  				break;
583  			continue;
584  		}
585  		if (tsp->coff + tsp->cols > sp->coff + sp->cols)
586  			break;
587  #ifdef DEBUG
588  		if (tlen < tsp->cols)
589  			abort();
590  #endif
591  		tlen -= tsp->cols + first;
592  		first = 1;
593  		*lp++ = tsp;
594  	}
595  	if (tlen == 0) {
596  		*lp = NULL;
597  		*jdirp = HORIZ_FOLLOW;
598  		return (0);
599  	}
600  	return (1);
601  }
602  
603  /*
604   * vs_fg --
605   *	Background the current screen, and foreground a new one.
606   *
607   * PUBLIC: int vs_fg(SCR *, SCR **, CHAR_T *, int);
608   */
609  int
vs_fg(SCR * sp,SCR ** nspp,CHAR_T * name,int newscreen)610  vs_fg(SCR *sp, SCR **nspp, CHAR_T *name, int newscreen)
611  {
612  	GS *gp;
613  	SCR *nsp;
614  	char *np;
615  	size_t nlen;
616  
617  	gp = sp->gp;
618  
619  	if (name)
620  	    INT2CHAR(sp, name, STRLEN(name) + 1, np, nlen);
621  	else
622  	    np = NULL;
623  	if (newscreen)
624  		/* Get the specified background screen. */
625  		nsp = vs_getbg(sp, np);
626  	else
627  		/* Swap screens. */
628  		if (vs_swap(sp, &nsp, np))
629  			return (1);
630  
631  	if ((*nspp = nsp) == NULL) {
632  		msgq_wstr(sp, M_ERR, name,
633  		    name == NULL ?
634  		    "223|There are no background screens" :
635  		    "224|There's no background screen editing a file named %s");
636  		return (1);
637  	}
638  
639  	if (newscreen) {
640  		/* Remove the new screen from the background queue. */
641  		TAILQ_REMOVE(gp->hq, nsp, q);
642  
643  		/* Split the screen; if we fail, hook the screen back in. */
644  		if (vs_split(sp, nsp, 0)) {
645  			TAILQ_INSERT_TAIL(gp->hq, nsp, q);
646  			return (1);
647  		}
648  	} else {
649  		/* Move the old screen to the background queue. */
650  		TAILQ_REMOVE(gp->dq, sp, q);
651  		TAILQ_INSERT_TAIL(gp->hq, sp, q);
652  	}
653  	return (0);
654  }
655  
656  /*
657   * vs_bg --
658   *	Background the screen, and switch to the next one.
659   *
660   * PUBLIC: int vs_bg(SCR *);
661   */
662  int
vs_bg(SCR * sp)663  vs_bg(SCR *sp)
664  {
665  	GS *gp;
666  	SCR *nsp;
667  
668  	gp = sp->gp;
669  
670  	/* Try and join with another screen. */
671  	if (vs_discard(sp, &nsp))
672  		return (1);
673  	if (nsp == NULL) {
674  		msgq(sp, M_ERR,
675  		    "225|You may not background your only displayed screen");
676  		return (1);
677  	}
678  
679  	/* Move the old screen to the background queue. */
680  	TAILQ_REMOVE(gp->dq, sp, q);
681  	TAILQ_INSERT_TAIL(gp->hq, sp, q);
682  
683  	/* Toss the screen map. */
684  	free(_HMAP(sp));
685  	_HMAP(sp) = NULL;
686  
687  	/* Switch screens. */
688  	sp->nextdisp = nsp;
689  	F_SET(sp, SC_SSWITCH);
690  
691  	return (0);
692  }
693  
694  /*
695   * vs_swap --
696   *	Swap the current screen with a backgrounded one.
697   *
698   * PUBLIC: int vs_swap(SCR *, SCR **, char *);
699   */
700  int
vs_swap(SCR * sp,SCR ** nspp,char * name)701  vs_swap(SCR *sp, SCR **nspp, char *name)
702  {
703  	GS *gp;
704  	SCR *nsp, *list[2];
705  
706  	gp = sp->gp;
707  
708  	/* Get the specified background screen. */
709  	if ((*nspp = nsp = vs_getbg(sp, name)) == NULL)
710  		return (0);
711  
712  	/*
713  	 * Save the old screen's cursor information.
714  	 *
715  	 * XXX
716  	 * If called after file_end(), and the underlying file was a tmp
717  	 * file, it may have gone away.
718  	 */
719  	if (sp->frp != NULL) {
720  		sp->frp->lno = sp->lno;
721  		sp->frp->cno = sp->cno;
722  		F_SET(sp->frp, FR_CURSORSET);
723  	}
724  
725  	/* Switch screens. */
726  	sp->nextdisp = nsp;
727  	F_SET(sp, SC_SSWITCH);
728  
729  	/* Initialize terminal information. */
730  	VIP(nsp)->srows = VIP(sp)->srows;
731  
732  	/* Initialize screen information. */
733  	nsp->cols = sp->cols;
734  	nsp->rows = sp->rows;	/* XXX: Only place in vi that sets rows. */
735  	nsp->roff = sp->roff;
736  
737  	/*
738  	 * Small screens: see vs_refresh.c, section 6a.
739  	 *
740  	 * The new screens may have different screen options sizes than the
741  	 * old one, so use them.  Make sure that text counts aren't larger
742  	 * than the new screen sizes.
743  	 */
744  	if (IS_SMALL(nsp)) {
745  		nsp->t_minrows = nsp->t_rows = O_VAL(nsp, O_WINDOW);
746  		if (nsp->t_rows > sp->t_maxrows)
747  			nsp->t_rows = nsp->t_maxrows;
748  		if (nsp->t_minrows > sp->t_maxrows)
749  			nsp->t_minrows = nsp->t_maxrows;
750  	} else
751  		nsp->t_rows = nsp->t_maxrows = nsp->t_minrows = nsp->rows - 1;
752  
753  	/* Reset the length of the default scroll. */
754  	nsp->defscroll = nsp->t_maxrows / 2;
755  
756  	/* Allocate a new screen map. */
757  	CALLOC_RET(nsp, _HMAP(nsp), SIZE_HMAP(nsp), sizeof(SMAP));
758  	_TMAP(nsp) = _HMAP(nsp) + (nsp->t_rows - 1);
759  
760  	/* Fill the map. */
761  	nsp->gp = sp->gp;
762  	if (vs_sm_fill(nsp, nsp->lno, P_FILL))
763  		return (1);
764  
765  	/*
766  	 * The new screen replaces the old screen in the parent/child list.
767  	 * We insert the new screen after the old one.  If we're exiting,
768  	 * the exit will delete the old one, if we're foregrounding, the fg
769  	 * code will move the old one to the background queue.
770  	 */
771  	TAILQ_REMOVE(gp->hq, nsp, q);
772  	TAILQ_INSERT_AFTER(gp->dq, sp, nsp, q);
773  
774  	/*
775  	 * Don't change the screen's cursor information other than to
776  	 * note that the cursor is wrong.
777  	 */
778  	F_SET(VIP(nsp), VIP_CUR_INVALID);
779  
780  	/* Draw the new screen from scratch, and add a status line. */
781  	F_SET(nsp, SC_SCR_REDRAW | SC_STATUS);
782  
783  	list[0] = nsp; list[1] = NULL;
784  	(void)gp->scr_discard(sp, list);
785  
786  	return (0);
787  }
788  
789  /*
790   * vs_resize --
791   *	Change the absolute size of the current screen.
792   *
793   * PUBLIC: int vs_resize(SCR *, long, adj_t);
794   */
795  int
vs_resize(SCR * sp,long int count,adj_t adj)796  vs_resize(SCR *sp, long int count, adj_t adj)
797  {
798  	GS *gp;
799  	SCR *g, *s, *prev, *next, *list[3] = {NULL, NULL, NULL};
800  	size_t g_off, s_off;
801  
802  	gp = sp->gp;
803  
804  	/*
805  	 * Figure out which screens will grow, which will shrink, and
806  	 * make sure it's possible.
807  	 */
808  	if (count == 0)
809  		return (0);
810  	if (adj == A_SET) {
811  		if (sp->t_maxrows == count)
812  			return (0);
813  		if (sp->t_maxrows > count) {
814  			adj = A_DECREASE;
815  			count = sp->t_maxrows - count;
816  		} else {
817  			adj = A_INCREASE;
818  			count = count - sp->t_maxrows;
819  		}
820  	}
821  
822  	/* Find first overlapping screen */
823  	for (next = TAILQ_NEXT(sp, q); next != NULL &&
824  	     (next->coff >= sp->coff + sp->cols ||
825  	      next->coff + next->cols <= sp->coff);
826  	     next = TAILQ_NEXT(next, q));
827  	/* See if we can use it */
828  	if (next != NULL &&
829  	    (sp->coff != next->coff || sp->cols != next->cols))
830  		next = NULL;
831  	for (prev = TAILQ_PREV(sp, _dqh, q); prev != NULL &&
832  	     (prev->coff >= sp->coff + sp->cols ||
833  	      prev->coff + prev->cols <= sp->coff);
834  	     prev = TAILQ_PREV(prev, _dqh, q));
835  	if (prev != NULL &&
836  	    (sp->coff != prev->coff || sp->cols != prev->cols))
837  		prev = NULL;
838  
839  	g_off = s_off = 0;
840  	if (adj == A_DECREASE) {
841  		if (count < 0)
842  			count = -count;
843  		s = sp;
844  		if (s->t_maxrows < MINIMUM_SCREEN_ROWS + count)
845  			goto toosmall;
846  		if ((g = prev) == NULL) {
847  			if ((g = next) == NULL)
848  				goto toobig;
849  			g_off = -count;
850  		} else
851  			s_off = count;
852  	} else {
853  		g = sp;
854  		if ((s = next) != NULL &&
855  		    s->t_maxrows >= MINIMUM_SCREEN_ROWS + count)
856  				s_off = count;
857  		else
858  			s = NULL;
859  		if (s == NULL) {
860  			if ((s = prev) == NULL) {
861  toobig:				msgq(sp, M_BERR, adj == A_DECREASE ?
862  				    "227|The screen cannot shrink" :
863  				    "228|The screen cannot grow");
864  				return (1);
865  			}
866  			if (s->t_maxrows < MINIMUM_SCREEN_ROWS + count) {
867  toosmall:			msgq(sp, M_BERR,
868  				    "226|The screen can only shrink to %d rows",
869  				    MINIMUM_SCREEN_ROWS);
870  				return (1);
871  			}
872  			g_off = -count;
873  		}
874  	}
875  
876  	/*
877  	 * Fix up the screens; we could optimize the reformatting of the
878  	 * screen, but this isn't likely to be a common enough operation
879  	 * to make it worthwhile.
880  	 */
881  	s->rows += -count;
882  	s->roff += s_off;
883  	g->rows += count;
884  	g->roff += g_off;
885  
886  	g->t_rows += count;
887  	if (g->t_minrows == g->t_maxrows)
888  		g->t_minrows += count;
889  	g->t_maxrows += count;
890  	_TMAP(g) += count;
891  	F_SET(g, SC_SCR_REFORMAT | SC_STATUS);
892  
893  	s->t_rows -= count;
894  	s->t_maxrows -= count;
895  	if (s->t_minrows > s->t_maxrows)
896  		s->t_minrows = s->t_maxrows;
897  	_TMAP(s) -= count;
898  	F_SET(s, SC_SCR_REFORMAT | SC_STATUS);
899  
900  	/* XXXX */
901  	list[0] = g; list[1] = s;
902  	gp->scr_discard(0, list);
903  
904  	return (0);
905  }
906  
907  /*
908   * vs_getbg --
909   *	Get the specified background screen, or, if name is NULL, the first
910   *	background screen.
911   */
912  static SCR *
vs_getbg(SCR * sp,char * name)913  vs_getbg(SCR *sp, char *name)
914  {
915  	GS *gp;
916  	SCR *nsp;
917  	char *p;
918  
919  	gp = sp->gp;
920  
921  	/* If name is NULL, return the first background screen on the list. */
922  	if (name == NULL)
923  		return (TAILQ_FIRST(gp->hq));
924  
925  	/* Search for a full match. */
926  	TAILQ_FOREACH(nsp, gp->hq, q)
927  		if (!strcmp(nsp->frp->name, name))
928  			break;
929  	if (nsp != NULL)
930  		return (nsp);
931  
932  	/* Search for a last-component match. */
933  	TAILQ_FOREACH(nsp, gp->hq, q) {
934  		if ((p = strrchr(nsp->frp->name, '/')) == NULL)
935  			p = nsp->frp->name;
936  		else
937  			++p;
938  		if (!strcmp(p, name))
939  			break;
940  	}
941  	if (nsp != NULL)
942  		return (nsp);
943  
944  	return (NULL);
945  }
946