contrib/nvi2/vi/vs_split.c

   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 #ifndef lint
  13 static const char sccsid[] = "$Id: vs_split.c,v 10.43 2015/04/05 15:21:55 zy Exp $";
  14 #endif /* not lint */
  15
  16 #include <sys/types.h>
  17 #include <sys/queue.h>
  18 #include <sys/time.h>
  19
  20 #include <bitstring.h>
  21 #include <errno.h>
  22 #include <limits.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26
  27 #include "../common/common.h"
  28 #include "vi.h"
  29
  30 typedef enum { HORIZ_FOLLOW, HORIZ_PRECEDE, VERT_FOLLOW, VERT_PRECEDE } jdir_t;
  31
  32 static SCR      *vs_getbg(SCR *, char *);
  33 static void      vs_insert(SCR *sp, GS *gp);
  34 static int       vs_join(SCR *, SCR **, jdir_t *);
  35
  36 /*
  37  * vs_split --
  38  *      Create a new screen, horizontally.
  39  *
  40  * PUBLIC: int vs_split(SCR *, SCR *, int);
  41  */
  42 int
  43 vs_split(
  44         SCR *sp,
  45         SCR *new,
  46         int ccl)                /* Colon-command line split. */
  47 {
  48         GS *gp;
  49         SMAP *smp;
  50         size_t half;
  51         int issmallscreen, splitup;
  52
  53         gp = sp->gp;
  54
  55         /* Check to see if it's possible. */
  56         /* XXX: The IS_ONELINE fix will change this, too. */
  57         if (sp->rows < 4) {
  58                 msgq(sp, M_ERR,
  59                     "222|Screen must be larger than %d lines to split", 4 - 1);
  60                 return (1);
  61         }
  62
  63         /* Wait for any messages in the screen. */
  64         vs_resolve(sp, NULL, 1);
  65
  66         /* Get a new screen map. */
  67         CALLOC(sp, _HMAP(new), SMAP *, SIZE_HMAP(sp), sizeof(SMAP));
  68         if (_HMAP(new) == NULL)
  69                 return (1);
  70         _HMAP(new)->lno = sp->lno;
  71         _HMAP(new)->coff = 0;
  72         _HMAP(new)->soff = 1;
  73
  74         /* Split the screen in half. */
  75         half = sp->rows / 2;
  76         if (ccl && half > 6)
  77                 half = 6;
  78
  79         /*
  80          * Small screens: see vs_refresh.c section 6a.  Set a flag so
  81          * we know to fix the screen up later.
  82          */
  83         issmallscreen = IS_SMALL(sp);
  84
  85         /* The columns in the screen don't change. */
  86         new->coff = sp->coff;
  87         new->cols = sp->cols;
  88
  89         /*
  90          * Split the screen, and link the screens together.  If creating a
  91          * screen to edit the colon command line or the cursor is in the top
  92          * half of the current screen, the new screen goes under the current
  93          * screen.  Else, it goes above the current screen.
  94          *
  95          * Recalculate current cursor position based on sp->lno, we're called
  96          * with the cursor on the colon command line.  Then split the screen
  97          * in half and update the shared information.
  98          */
  99         splitup =
 100             !ccl && (vs_sm_cursor(sp, &smp) ? 0 : (smp - HMAP) + 1) >= half;
 101         if (splitup) {                          /* Old is bottom half. */
 102                 new->rows = sp->rows - half;    /* New. */
 103                 new->roff = sp->roff;
 104                 sp->rows = half;                /* Old. */
 105                 sp->roff += new->rows;
 106
 107                 /*
 108                  * If the parent is the bottom half of the screen, shift
 109                  * the map down to match on-screen text.
 110                  */
 111                 memcpy(_HMAP(sp), _HMAP(sp) + new->rows,
 112                     (sp->t_maxrows - new->rows) * sizeof(SMAP));
 113         } else {                                /* Old is top half. */
 114                 new->rows = half;               /* New. */
 115                 sp->rows -= half;               /* Old. */
 116                 new->roff = sp->roff + sp->rows;
 117         }
 118
 119         /* Adjust maximum text count. */
 120         sp->t_maxrows = IS_ONELINE(sp) ? 1 : sp->rows - 1;
 121         new->t_maxrows = IS_ONELINE(new) ? 1 : new->rows - 1;
 122
 123         /*
 124          * Small screens: see vs_refresh.c, section 6a.
 125          *
 126          * The child may have different screen options sizes than the parent,
 127          * so use them.  Guarantee that text counts aren't larger than the
 128          * new screen sizes.
 129          */
 130         if (issmallscreen) {
 131                 /* Fix the text line count for the parent. */
 132                 if (splitup)
 133                         sp->t_rows -= new->rows;
 134
 135                 /* Fix the parent screen. */
 136                 if (sp->t_rows > sp->t_maxrows)
 137                         sp->t_rows = sp->t_maxrows;
 138                 if (sp->t_minrows > sp->t_maxrows)
 139                         sp->t_minrows = sp->t_maxrows;
 140
 141                 /* Fix the child screen. */
 142                 new->t_minrows = new->t_rows = O_VAL(sp, O_WINDOW);
 143                 if (new->t_rows > new->t_maxrows)
 144                         new->t_rows = new->t_maxrows;
 145                 if (new->t_minrows > new->t_maxrows)
 146                         new->t_minrows = new->t_maxrows;
 147         } else {
 148                 sp->t_minrows = sp->t_rows = IS_ONELINE(sp) ? 1 : sp->rows - 1;
 149
 150                 /*
 151                  * The new screen may be a small screen, even if the parent
 152                  * was not.  Don't complain if O_WINDOW is too large, we're
 153                  * splitting the screen so the screen is much smaller than
 154                  * normal.
 155                  */
 156                 new->t_minrows = new->t_rows = O_VAL(sp, O_WINDOW);
 157                 if (new->t_rows > new->rows - 1)
 158                         new->t_minrows = new->t_rows =
 159                             IS_ONELINE(new) ? 1 : new->rows - 1;
 160         }
 161
 162         /* Adjust the ends of the new and old maps. */
 163         _TMAP(sp) = IS_ONELINE(sp) ?
 164             _HMAP(sp) : _HMAP(sp) + (sp->t_rows - 1);
 165         _TMAP(new) = IS_ONELINE(new) ?
 166             _HMAP(new) : _HMAP(new) + (new->t_rows - 1);
 167
 168         /* Reset the length of the default scroll. */
 169         if ((sp->defscroll = sp->t_maxrows / 2) == 0)
 170                 sp->defscroll = 1;
 171         if ((new->defscroll = new->t_maxrows / 2) == 0)
 172                 new->defscroll = 1;
 173
 174         /* Fit the screen into the logical chain. */
 175         vs_insert(new, sp->gp);
 176
 177         /* Tell the display that we're splitting. */
 178         (void)gp->scr_split(sp, new);
 179
 180         /*
 181          * Initialize the screen flags:
 182          *
 183          * If we're in vi mode in one screen, we don't have to reinitialize.
 184          * This isn't just a cosmetic fix.  The path goes like this:
 185          *
 186          *      return into vi(), SC_SSWITCH set
 187          *      call vs_refresh() with SC_STATUS set
 188          *      call vs_resolve to display the status message
 189          *      call vs_refresh() because the SC_SCR_VI bit isn't set
 190          *
 191          * Things go downhill at this point.
 192          *
 193          * Draw the new screen from scratch, and add a status line.
 194          */
 195         F_SET(new,
 196             SC_SCR_REFORMAT | SC_STATUS |
 197             F_ISSET(sp, SC_EX | SC_VI | SC_SCR_VI | SC_SCR_EX | SC_READONLY));
 198         return (0);
 199 }
 200
 201 /*
 202  * vs_vsplit --
 203  *      Create a new screen, vertically.
 204  *
 205  * PUBLIC: int vs_vsplit(SCR *, SCR *);
 206  */
 207 int
 208 vs_vsplit(SCR *sp, SCR *new)
 209 {
 210         GS *gp;
 211         size_t cols;
 212
 213         gp = sp->gp;
 214
 215         /* Check to see if it's possible. */
 216         if (sp->cols / 2 <= MINIMUM_SCREEN_COLS) {
 217                 msgq(sp, M_ERR,
 218                     "288|Screen must be larger than %d columns to split",
 219                     MINIMUM_SCREEN_COLS * 2);
 220                 return (1);
 221         }
 222
 223         /* Wait for any messages in the screen. */
 224         vs_resolve(sp, NULL, 1);
 225
 226         /* Get a new screen map. */
 227         CALLOC(sp, _HMAP(new), SMAP *, SIZE_HMAP(sp), sizeof(SMAP));
 228         if (_HMAP(new) == NULL)
 229                 return (1);
 230         _HMAP(new)->lno = sp->lno;
 231         _HMAP(new)->coff = 0;
 232         _HMAP(new)->soff = 1;
 233
 234         /*
 235          * Split the screen in half; we have to sacrifice a column to delimit
 236          * the screens.
 237          *
 238          * XXX
 239          * We always split to the right... that makes more sense to me, and
 240          * I don't want to play the stupid games that I play when splitting
 241          * horizontally.
 242          *
 243          * XXX
 244          * We reserve a column for the screen, "knowing" that curses needs
 245          * one.  This should be worked out with the display interface.
 246          */
 247         cols = sp->cols / 2;
 248         new->cols = sp->cols - cols - 1;
 249         sp->cols = cols;
 250         new->coff = sp->coff + cols + 1;
 251         sp->cno = 0;
 252
 253         /* Nothing else changes. */
 254         new->rows = sp->rows;
 255         new->t_rows = sp->t_rows;
 256         new->t_maxrows = sp->t_maxrows;
 257         new->t_minrows = sp->t_minrows;
 258         new->roff = sp->roff;
 259         new->defscroll = sp->defscroll;
 260         _TMAP(new) = _HMAP(new) + (new->t_rows - 1);
 261
 262         /* Fit the screen into the logical chain. */
 263         vs_insert(new, sp->gp);
 264
 265         /* Tell the display that we're splitting. */
 266         (void)gp->scr_split(sp, new);
 267
 268         /* Redraw the old screen from scratch. */
 269         F_SET(sp, SC_SCR_REFORMAT | SC_STATUS);
 270
 271         /*
 272          * Initialize the screen flags:
 273          *
 274          * If we're in vi mode in one screen, we don't have to reinitialize.
 275          * This isn't just a cosmetic fix.  The path goes like this:
 276          *
 277          *      return into vi(), SC_SSWITCH set
 278          *      call vs_refresh() with SC_STATUS set
 279          *      call vs_resolve to display the status message
 280          *      call vs_refresh() because the SC_SCR_VI bit isn't set
 281          *
 282          * Things go downhill at this point.
 283          *
 284          * Draw the new screen from scratch, and add a status line.
 285          */
 286         F_SET(new,
 287             SC_SCR_REFORMAT | SC_STATUS |
 288             F_ISSET(sp, SC_EX | SC_VI | SC_SCR_VI | SC_SCR_EX | SC_READONLY));
 289         return (0);
 290 }
 291
 292 /*
 293  * vs_insert --
 294  *      Insert the new screen into the correct place in the logical
 295  *      chain.
 296  */
 297 static void
 298 vs_insert(SCR *sp, GS *gp)
 299 {
 300         SCR *tsp;
 301
 302         gp = sp->gp;
 303
 304         /* Move past all screens with lower row numbers. */
 305         TAILQ_FOREACH(tsp, gp->dq, q)
 306                 if (tsp->roff >= sp->roff)
 307                         break;
 308         /*
 309          * Move past all screens with the same row number and lower
 310          * column numbers.
 311          */
 312         for (; tsp != NULL; tsp = TAILQ_NEXT(tsp, q))
 313                 if (tsp->roff != sp->roff || tsp->coff > sp->coff)
 314                         break;
 315
 316         /*
 317          * If we reached the end, this screen goes there.  Otherwise,
 318          * put it before or after the screen where we stopped.
 319          */
 320         if (tsp == NULL) {
 321                 TAILQ_INSERT_TAIL(gp->dq, sp, q);
 322         } else if (tsp->roff < sp->roff ||
 323             (tsp->roff == sp->roff && tsp->coff < sp->coff)) {
 324                 TAILQ_INSERT_AFTER(gp->dq, tsp, sp, q);
 325         } else
 326                 TAILQ_INSERT_BEFORE(tsp, sp, q);
 327 }
 328
 329 /*
 330  * vs_discard --
 331  *      Discard the screen, folding the real-estate into a related screen,
 332  *      if one exists, and return that screen.
 333  *
 334  * PUBLIC: int vs_discard(SCR *, SCR **);
 335  */
 336 int
 337 vs_discard(SCR *sp, SCR **spp)
 338 {
 339         GS *gp;
 340         SCR *tsp, **lp, *list[100];
 341         jdir_t jdir;
 342
 343         gp = sp->gp;
 344
 345         /*
 346          * Save the old screen's cursor information.
 347          *
 348          * XXX
 349          * If called after file_end(), and the underlying file was a tmp
 350          * file, it may have gone away.
 351          */
 352         if (sp->frp != NULL) {
 353                 sp->frp->lno = sp->lno;
 354                 sp->frp->cno = sp->cno;
 355                 F_SET(sp->frp, FR_CURSORSET);
 356         }
 357
 358         /* If no other screens to join, we're done. */
 359         if (!IS_SPLIT(sp)) {
 360                 (void)gp->scr_discard(sp, NULL);
 361
 362                 if (spp != NULL)
 363                         *spp = NULL;
 364                 return (0);
 365         }
 366
 367         /*
 368          * Find a set of screens that cover one of the screen's borders.
 369          * Check the vertical axis first, for no particular reason.
 370          *
 371          * XXX
 372          * It's possible (I think?), to create a screen that shares no full
 373          * border with any other set of screens, so we can't discard it.  We
 374          * just complain at the user until they clean it up.
 375          */
 376         if (vs_join(sp, list, &jdir))
 377                 return (1);
 378
 379         /*
 380          * Modify the affected screens.  Redraw the modified screen(s) from
 381          * scratch, setting a status line.  If this is ever a performance
 382          * problem we could play games with the map, but I wrote that code
 383          * before and it was never clean or easy.
 384          *
 385          * Don't clean up the discarded screen's information.  If the screen
 386          * isn't exiting, we'll do the work when the user redisplays it.
 387          */
 388         switch (jdir) {
 389         case HORIZ_FOLLOW:
 390         case HORIZ_PRECEDE:
 391                 for (lp = &list[0]; (tsp = *lp) != NULL; ++lp) {
 392                         /*
 393                          * Small screens: see vs_refresh.c section 6a.  Adjust
 394                          * text line info, unless it's a small screen.
 395                          *
 396                          * Reset the length of the default scroll.
 397                          *
 398                          * Reset the map references.
 399                          */
 400                         tsp->rows += sp->rows;
 401                         if (!IS_SMALL(tsp))
 402                                 tsp->t_rows = tsp->t_minrows = tsp->rows - 1;
 403                         tsp->t_maxrows = tsp->rows - 1;
 404
 405                         tsp->defscroll = tsp->t_maxrows / 2;
 406
 407                         *(_HMAP(tsp) + (tsp->t_rows - 1)) = *_TMAP(tsp);
 408                         _TMAP(tsp) = _HMAP(tsp) + (tsp->t_rows - 1);
 409
 410                         switch (jdir) {
 411                         case HORIZ_FOLLOW:
 412                                 tsp->roff = sp->roff;
 413                                 vs_sm_fill(tsp, OOBLNO, P_TOP);
 414                                 break;
 415                         case HORIZ_PRECEDE:
 416                                 vs_sm_fill(tsp, OOBLNO, P_BOTTOM);
 417                                 break;
 418                         default:
 419                                 abort();
 420                         }
 421                         F_SET(tsp, SC_STATUS);
 422                 }
 423                 break;
 424         case VERT_FOLLOW:
 425         case VERT_PRECEDE:
 426                 for (lp = &list[0]; (tsp = *lp) != NULL; ++lp) {
 427                         if (jdir == VERT_FOLLOW)
 428                                 tsp->coff = sp->coff;
 429                         tsp->cols += sp->cols + 1;      /* XXX: DIVIDER */
 430                         vs_sm_fill(tsp, OOBLNO, P_TOP);
 431                         F_SET(tsp, SC_STATUS);
 432                 }
 433                 break;
 434         default:
 435                 abort();
 436         }
 437
 438         /* Find the closest screen that changed and move to it. */
 439         tsp = list[0];
 440         if (spp != NULL)
 441                 *spp = tsp;
 442
 443         /* Tell the display that we're discarding a screen. */
 444         (void)gp->scr_discard(sp, list);
 445
 446         return (0);
 447 }
 448
 449 /*
 450  * vs_join --
 451  *      Find a set of screens that covers a screen's border.
 452  */
 453 static int
 454 vs_join(SCR *sp, SCR **listp, jdir_t *jdirp)
 455 {
 456         GS *gp;
 457         SCR **lp, *tsp;
 458         int first;
 459         size_t tlen;
 460
 461         gp = sp->gp;
 462
 463         /* Check preceding vertical. */
 464         for (lp = listp, tlen = sp->rows,
 465             tsp = TAILQ_FIRST(gp->dq);
 466             tsp != NULL; tsp = TAILQ_NEXT(tsp, q)) {
 467                 if (sp == tsp)
 468                         continue;
 469                 /* Test if precedes the screen vertically. */
 470                 if (tsp->coff + tsp->cols + 1 != sp->coff)
 471                         continue;
 472                 /*
 473                  * Test if a subset on the vertical axis.  If overlaps the
 474                  * beginning or end, we can't join on this axis at all.
 475                  */
 476                 if (tsp->roff > sp->roff + sp->rows)
 477                         continue;
 478                 if (tsp->roff < sp->roff) {
 479                         if (tsp->roff + tsp->rows >= sp->roff)
 480                                 break;
 481                         continue;
 482                 }
 483                 if (tsp->roff + tsp->rows > sp->roff + sp->rows)
 484                         break;
 485 #ifdef DEBUG
 486                 if (tlen < tsp->rows)
 487                         abort();
 488 #endif
 489                 tlen -= tsp->rows;
 490                 *lp++ = tsp;
 491         }
 492         if (tlen == 0) {
 493                 *lp = NULL;
 494                 *jdirp = VERT_PRECEDE;
 495                 return (0);
 496         }
 497
 498         /* Check following vertical. */
 499         for (lp = listp, tlen = sp->rows,
 500             tsp = TAILQ_FIRST(gp->dq);
 501             tsp != NULL; tsp = TAILQ_NEXT(tsp, q)) {
 502                 if (sp == tsp)
 503                         continue;
 504                 /* Test if follows the screen vertically. */
 505                 if (tsp->coff != sp->coff + sp->cols + 1)
 506                         continue;
 507                 /*
 508                  * Test if a subset on the vertical axis.  If overlaps the
 509                  * beginning or end, we can't join on this axis at all.
 510                  */
 511                 if (tsp->roff > sp->roff + sp->rows)
 512                         continue;
 513                 if (tsp->roff < sp->roff) {
 514                         if (tsp->roff + tsp->rows >= sp->roff)
 515                                 break;
 516                         continue;
 517                 }
 518                 if (tsp->roff + tsp->rows > sp->roff + sp->rows)
 519                         break;
 520 #ifdef DEBUG
 521                 if (tlen < tsp->rows)
 522                         abort();
 523 #endif
 524                 tlen -= tsp->rows;
 525                 *lp++ = tsp;
 526         }
 527         if (tlen == 0) {
 528                 *lp = NULL;
 529                 *jdirp = VERT_FOLLOW;
 530                 return (0);
 531         }
 532
 533         /* Check preceding horizontal. */
 534         for (first = 0, lp = listp, tlen = sp->cols,
 535             tsp = TAILQ_FIRST(gp->dq);
 536             tsp != NULL; tsp = TAILQ_NEXT(tsp, q)) {
 537                 if (sp == tsp)
 538                         continue;
 539                 /* Test if precedes the screen horizontally. */
 540                 if (tsp->roff + tsp->rows != sp->roff)
 541                         continue;
 542                 /*
 543                  * Test if a subset on the horizontal axis.  If overlaps the
 544                  * beginning or end, we can't join on this axis at all.
 545                  */
 546                 if (tsp->coff > sp->coff + sp->cols)
 547                         continue;
 548                 if (tsp->coff < sp->coff) {
 549                         if (tsp->coff + tsp->cols >= sp->coff)
 550                                 break;
 551                         continue;
 552                 }
 553                 if (tsp->coff + tsp->cols > sp->coff + sp->cols)
 554                         break;
 555 #ifdef DEBUG
 556                 if (tlen < tsp->cols)
 557                         abort();
 558 #endif
 559                 tlen -= tsp->cols + first;
 560                 first = 1;
 561                 *lp++ = tsp;
 562         }
 563         if (tlen == 0) {
 564                 *lp = NULL;
 565                 *jdirp = HORIZ_PRECEDE;
 566                 return (0);
 567         }
 568
 569         /* Check following horizontal. */
 570         for (first = 0, lp = listp, tlen = sp->cols,
 571             tsp = TAILQ_FIRST(gp->dq);
 572             tsp != NULL; tsp = TAILQ_NEXT(tsp, q)) {
 573                 if (sp == tsp)
 574                         continue;
 575                 /* Test if precedes the screen horizontally. */
 576                 if (tsp->roff != sp->roff + sp->rows)
 577                         continue;
 578                 /*
 579                  * Test if a subset on the horizontal axis.  If overlaps the
 580                  * beginning or end, we can't join on this axis at all.
 581                  */
 582                 if (tsp->coff > sp->coff + sp->cols)
 583                         continue;
 584                 if (tsp->coff < sp->coff) {
 585                         if (tsp->coff + tsp->cols >= sp->coff)
 586                                 break;
 587                         continue;
 588                 }
 589                 if (tsp->coff + tsp->cols > sp->coff + sp->cols)
 590                         break;
 591 #ifdef DEBUG
 592                 if (tlen < tsp->cols)
 593                         abort();
 594 #endif
 595                 tlen -= tsp->cols + first;
 596                 first = 1;
 597                 *lp++ = tsp;
 598         }
 599         if (tlen == 0) {
 600                 *lp = NULL;
 601                 *jdirp = HORIZ_FOLLOW;
 602                 return (0);
 603         }
 604         return (1);
 605 }
 606
 607 /*
 608  * vs_fg --
 609  *      Background the current screen, and foreground a new one.
 610  *
 611  * PUBLIC: int vs_fg(SCR *, SCR **, CHAR_T *, int);
 612  */
 613 int
 614 vs_fg(SCR *sp, SCR **nspp, CHAR_T *name, int newscreen)
 615 {
 616         GS *gp;
 617         SCR *nsp;
 618         char *np;
 619         size_t nlen;
 620
 621         gp = sp->gp;
 622
 623         if (name)
 624             INT2CHAR(sp, name, STRLEN(name) + 1, np, nlen);
 625         else
 626             np = NULL;
 627         if (newscreen)
 628                 /* Get the specified background screen. */
 629                 nsp = vs_getbg(sp, np);
 630         else
 631                 /* Swap screens. */
 632                 if (vs_swap(sp, &nsp, np))
 633                         return (1);
 634
 635         if ((*nspp = nsp) == NULL) {
 636                 msgq_wstr(sp, M_ERR, name,
 637                     name == NULL ?
 638                     "223|There are no background screens" :
 639                     "224|There's no background screen editing a file named %s");
 640                 return (1);
 641         }
 642
 643         if (newscreen) {
 644                 /* Remove the new screen from the background queue. */
 645                 TAILQ_REMOVE(gp->hq, nsp, q);
 646
 647                 /* Split the screen; if we fail, hook the screen back in. */
 648                 if (vs_split(sp, nsp, 0)) {
 649                         TAILQ_INSERT_TAIL(gp->hq, nsp, q);
 650                         return (1);
 651                 }
 652         } else {
 653                 /* Move the old screen to the background queue. */
 654                 TAILQ_REMOVE(gp->dq, sp, q);
 655                 TAILQ_INSERT_TAIL(gp->hq, sp, q);
 656         }
 657         return (0);
 658 }
 659
 660 /*
 661  * vs_bg --
 662  *      Background the screen, and switch to the next one.
 663  *
 664  * PUBLIC: int vs_bg(SCR *);
 665  */
 666 int
 667 vs_bg(SCR *sp)
 668 {
 669         GS *gp;
 670         SCR *nsp;
 671
 672         gp = sp->gp;
 673
 674         /* Try and join with another screen. */
 675         if (vs_discard(sp, &nsp))
 676                 return (1);
 677         if (nsp == NULL) {
 678                 msgq(sp, M_ERR,
 679                     "225|You may not background your only displayed screen");
 680                 return (1);
 681         }
 682
 683         /* Move the old screen to the background queue. */
 684         TAILQ_REMOVE(gp->dq, sp, q);
 685         TAILQ_INSERT_TAIL(gp->hq, sp, q);
 686
 687         /* Toss the screen map. */
 688         free(_HMAP(sp));
 689         _HMAP(sp) = NULL;
 690
 691         /* Switch screens. */
 692         sp->nextdisp = nsp;
 693         F_SET(sp, SC_SSWITCH);
 694
 695         return (0);
 696 }
 697
 698 /*
 699  * vs_swap --
 700  *      Swap the current screen with a backgrounded one.
 701  *
 702  * PUBLIC: int vs_swap(SCR *, SCR **, char *);
 703  */
 704 int
 705 vs_swap(SCR *sp, SCR **nspp, char *name)
 706 {
 707         GS *gp;
 708         SCR *nsp, *list[2];
 709
 710         gp = sp->gp;
 711
 712         /* Get the specified background screen. */
 713         if ((*nspp = nsp = vs_getbg(sp, name)) == NULL)
 714                 return (0);
 715
 716         /*
 717          * Save the old screen's cursor information.
 718          *
 719          * XXX
 720          * If called after file_end(), and the underlying file was a tmp
 721          * file, it may have gone away.
 722          */
 723         if (sp->frp != NULL) {
 724                 sp->frp->lno = sp->lno;
 725                 sp->frp->cno = sp->cno;
 726                 F_SET(sp->frp, FR_CURSORSET);
 727         }
 728
 729         /* Switch screens. */
 730         sp->nextdisp = nsp;
 731         F_SET(sp, SC_SSWITCH);
 732
 733         /* Initialize terminal information. */
 734         VIP(nsp)->srows = VIP(sp)->srows;
 735
 736         /* Initialize screen information. */
 737         nsp->cols = sp->cols;
 738         nsp->rows = sp->rows;   /* XXX: Only place in vi that sets rows. */
 739         nsp->roff = sp->roff;
 740
 741         /*
 742          * Small screens: see vs_refresh.c, section 6a.
 743          *
 744          * The new screens may have different screen options sizes than the
 745          * old one, so use them.  Make sure that text counts aren't larger
 746          * than the new screen sizes.
 747          */
 748         if (IS_SMALL(nsp)) {
 749                 nsp->t_minrows = nsp->t_rows = O_VAL(nsp, O_WINDOW);
 750                 if (nsp->t_rows > sp->t_maxrows)
 751                         nsp->t_rows = nsp->t_maxrows;
 752                 if (nsp->t_minrows > sp->t_maxrows)
 753                         nsp->t_minrows = nsp->t_maxrows;
 754         } else
 755                 nsp->t_rows = nsp->t_maxrows = nsp->t_minrows = nsp->rows - 1;
 756
 757         /* Reset the length of the default scroll. */
 758         nsp->defscroll = nsp->t_maxrows / 2;
 759
 760         /* Allocate a new screen map. */
 761         CALLOC_RET(nsp, _HMAP(nsp), SMAP *, SIZE_HMAP(nsp), sizeof(SMAP));
 762         _TMAP(nsp) = _HMAP(nsp) + (nsp->t_rows - 1);
 763
 764         /* Fill the map. */
 765         nsp->gp = sp->gp;
 766         if (vs_sm_fill(nsp, nsp->lno, P_FILL))
 767                 return (1);
 768
 769         /*
 770          * The new screen replaces the old screen in the parent/child list.
 771          * We insert the new screen after the old one.  If we're exiting,
 772          * the exit will delete the old one, if we're foregrounding, the fg
 773          * code will move the old one to the background queue.
 774          */
 775         TAILQ_REMOVE(gp->hq, nsp, q);
 776         TAILQ_INSERT_AFTER(gp->dq, sp, nsp, q);
 777
 778         /*
 779          * Don't change the screen's cursor information other than to
 780          * note that the cursor is wrong.
 781          */
 782         F_SET(VIP(nsp), VIP_CUR_INVALID);
 783
 784         /* Draw the new screen from scratch, and add a status line. */
 785         F_SET(nsp, SC_SCR_REDRAW | SC_STATUS);
 786
 787         list[0] = nsp; list[1] = NULL;
 788         (void)gp->scr_discard(sp, list);
 789
 790         return (0);
 791 }
 792
 793 /*
 794  * vs_resize --
 795  *      Change the absolute size of the current screen.
 796  *
 797  * PUBLIC: int vs_resize(SCR *, long, adj_t);
 798  */
 799 int
 800 vs_resize(SCR *sp, long int count, adj_t adj)
 801 {
 802         GS *gp;
 803         SCR *g, *s, *prev, *next, *list[3] = {NULL, NULL, NULL};
 804         size_t g_off, s_off;
 805
 806         gp = sp->gp;
 807
 808         /*
 809          * Figure out which screens will grow, which will shrink, and
 810          * make sure it's possible.
 811          */
 812         if (count == 0)
 813                 return (0);
 814         if (adj == A_SET) {
 815                 if (sp->t_maxrows == count)
 816                         return (0);
 817                 if (sp->t_maxrows > count) {
 818                         adj = A_DECREASE;
 819                         count = sp->t_maxrows - count;
 820                 } else {
 821                         adj = A_INCREASE;
 822                         count = count - sp->t_maxrows;
 823                 }
 824         }
 825
 826         /* Find first overlapping screen */
 827         for (next = TAILQ_NEXT(sp, q); next != NULL &&
 828              (next->coff >= sp->coff + sp->cols ||
 829               next->coff + next->cols <= sp->coff);
 830              next = TAILQ_NEXT(next, q));
 831         /* See if we can use it */
 832         if (next != NULL &&
 833             (sp->coff != next->coff || sp->cols != next->cols))
 834                 next = NULL;
 835         for (prev = TAILQ_PREV(sp, _dqh, q); prev != NULL &&
 836              (prev->coff >= sp->coff + sp->cols ||
 837               prev->coff + prev->cols <= sp->coff);
 838              prev = TAILQ_PREV(prev, _dqh, q));
 839         if (prev != NULL &&
 840             (sp->coff != prev->coff || sp->cols != prev->cols))
 841                 prev = NULL;
 842
 843         g_off = s_off = 0;
 844         if (adj == A_DECREASE) {
 845                 if (count < 0)
 846                         count = -count;
 847                 s = sp;
 848                 if (s->t_maxrows < MINIMUM_SCREEN_ROWS + count)
 849                         goto toosmall;
 850                 if ((g = prev) == NULL) {
 851                         if ((g = next) == NULL)
 852                                 goto toobig;
 853                         g_off = -count;
 854                 } else
 855                         s_off = count;
 856         } else {
 857                 g = sp;
 858                 if ((s = next) != NULL &&
 859                     s->t_maxrows >= MINIMUM_SCREEN_ROWS + count)
 860                                 s_off = count;
 861                 else
 862                         s = NULL;
 863                 if (s == NULL) {
 864                         if ((s = prev) == NULL) {
 865 toobig:                         msgq(sp, M_BERR, adj == A_DECREASE ?
 866                                     "227|The screen cannot shrink" :
 867                                     "228|The screen cannot grow");
 868                                 return (1);
 869                         }
 870                         if (s->t_maxrows < MINIMUM_SCREEN_ROWS + count) {
 871 toosmall:                       msgq(sp, M_BERR,
 872                                     "226|The screen can only shrink to %d rows",
 873                                     MINIMUM_SCREEN_ROWS);
 874                                 return (1);
 875                         }
 876                         g_off = -count;
 877                 }
 878         }
 879
 880         /*
 881          * Fix up the screens; we could optimize the reformatting of the
 882          * screen, but this isn't likely to be a common enough operation
 883          * to make it worthwhile.
 884          */
 885         s->rows += -count;
 886         s->roff += s_off;
 887         g->rows += count;
 888         g->roff += g_off;
 889
 890         g->t_rows += count;
 891         if (g->t_minrows == g->t_maxrows)
 892                 g->t_minrows += count;
 893         g->t_maxrows += count;
 894         _TMAP(g) += count;
 895         F_SET(g, SC_SCR_REFORMAT | SC_STATUS);
 896
 897         s->t_rows -= count;
 898         s->t_maxrows -= count;
 899         if (s->t_minrows > s->t_maxrows)
 900                 s->t_minrows = s->t_maxrows;
 901         _TMAP(s) -= count;
 902         F_SET(s, SC_SCR_REFORMAT | SC_STATUS);
 903
 904         /* XXXX */
 905         list[0] = g; list[1] = s;
 906         gp->scr_discard(0, list);
 907
 908         return (0);
 909 }
 910
 911 /*
 912  * vs_getbg --
 913  *      Get the specified background screen, or, if name is NULL, the first
 914  *      background screen.
 915  */
 916 static SCR *
 917 vs_getbg(SCR *sp, char *name)
 918 {
 919         GS *gp;
 920         SCR *nsp;
 921         char *p;
 922
 923         gp = sp->gp;
 924
 925         /* If name is NULL, return the first background screen on the list. */
 926         if (name == NULL)
 927                 return (TAILQ_FIRST(gp->hq));
 928
 929         /* Search for a full match. */
 930         TAILQ_FOREACH(nsp, gp->hq, q)
 931                 if (!strcmp(nsp->frp->name, name))
 932                         break;
 933         if (nsp != NULL)
 934                 return (nsp);
 935
 936         /* Search for a last-component match. */
 937         TAILQ_FOREACH(nsp, gp->hq, q) {
 938                 if ((p = strrchr(nsp->frp->name, '/')) == NULL)
 939                         p = nsp->frp->name;
 940                 else
 941                         ++p;
 942                 if (!strcmp(p, name))
 943                         break;
 944         }
 945         if (nsp != NULL)
 946                 return (nsp);
 947
 948         return (NULL);
 949 }