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 10.34 1996/12/18 10:24:31 bostic Exp $ (Berkeley) $Date: 1996/12/18 10:24:31 $";
  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 __P((SCR *, char *));
  33 static void      vs_insert __P((SCR *));
  34 static int       vs_join __P((SCR *, SCR **, jdir_t *));
  35
  36 /*
  37  * vs_split --
  38  *      Create a new screen, horizontally.
  39  *
  40  * PUBLIC: int vs_split __P((SCR *, SCR *, int));
  41  */
  42 int
  43 vs_split(sp, new, ccl)
  44         SCR *sp, *new;
  45         int ccl;                /* Colon-command line split. */
  46 {
  47         GS *gp;
  48         SMAP *smp;
  49         size_t half;
  50         int issmallscreen, splitup;
  51
  52         gp = sp->gp;
  53
  54         /* Check to see if it's possible. */
  55         /* XXX: The IS_ONELINE fix will change this, too. */
  56         if (sp->rows < 4) {
  57                 msgq(sp, M_ERR,
  58                     "222|Screen must be larger than %d lines to split", 4 - 1);
  59                 return (1);
  60         }
  61
  62         /* Wait for any messages in the screen. */
  63         vs_resolve(sp, NULL, 1);
  64
  65         /* Get a new screen map. */
  66         CALLOC(sp, _HMAP(new), SMAP *, SIZE_HMAP(sp), sizeof(SMAP));
  67         if (_HMAP(new) == NULL)
  68                 return (1);
  69         _HMAP(new)->lno = sp->lno;
  70         _HMAP(new)->coff = 0;
  71         _HMAP(new)->soff = 1;
  72
  73         /* Split the screen in half. */
  74         half = sp->rows / 2;
  75         if (ccl && half > 6)
  76                 half = 6;
  77
  78         /*
  79          * Small screens: see vs_refresh.c section 6a.  Set a flag so
  80          * we know to fix the screen up later.
  81          */
  82         issmallscreen = IS_SMALL(sp);
  83
  84         /* The columns in the screen don't change. */
  85         new->coff = sp->coff;
  86         new->cols = sp->cols;
  87
  88         /*
  89          * Split the screen, and link the screens together.  If creating a
  90          * screen to edit the colon command line or the cursor is in the top
  91          * half of the current screen, the new screen goes under the current
  92          * screen.  Else, it goes above the current screen.
  93          *
  94          * Recalculate current cursor position based on sp->lno, we're called
  95          * with the cursor on the colon command line.  Then split the screen
  96          * in half and update the shared information.
  97          */
  98         splitup =
  99             !ccl && (vs_sm_cursor(sp, &smp) ? 0 : (smp - HMAP) + 1) >= half;
 100         if (splitup) {                          /* Old is bottom half. */
 101                 new->rows = sp->rows - half;    /* New. */
 102                 new->roff = sp->roff;
 103                 sp->rows = half;                /* Old. */
 104                 sp->roff += new->rows;
 105
 106                 /*
 107                  * If the parent is the bottom half of the screen, shift
 108                  * the map down to match on-screen text.
 109                  */
 110                 memcpy(_HMAP(sp), _HMAP(sp) + new->rows,
 111                     (sp->t_maxrows - new->rows) * sizeof(SMAP));
 112         } else {                                /* Old is top half. */
 113                 new->rows = half;               /* New. */
 114                 sp->rows -= half;               /* Old. */
 115                 new->roff = sp->roff + sp->rows;
 116         }
 117
 118         /* Adjust maximum text count. */
 119         sp->t_maxrows = IS_ONELINE(sp) ? 1 : sp->rows - 1;
 120         new->t_maxrows = IS_ONELINE(new) ? 1 : new->rows - 1;
 121
 122         /*
 123          * Small screens: see vs_refresh.c, section 6a.
 124          *
 125          * The child may have different screen options sizes than the parent,
 126          * so use them.  Guarantee that text counts aren't larger than the
 127          * new screen sizes.
 128          */
 129         if (issmallscreen) {
 130                 /* Fix the text line count for the parent. */
 131                 if (splitup)
 132                         sp->t_rows -= new->rows;
 133
 134                 /* Fix the parent screen. */
 135                 if (sp->t_rows > sp->t_maxrows)
 136                         sp->t_rows = sp->t_maxrows;
 137                 if (sp->t_minrows > sp->t_maxrows)
 138                         sp->t_minrows = sp->t_maxrows;
 139
 140                 /* Fix the child screen. */
 141                 new->t_minrows = new->t_rows = O_VAL(sp, O_WINDOW);
 142                 if (new->t_rows > new->t_maxrows)
 143                         new->t_rows = new->t_maxrows;
 144                 if (new->t_minrows > new->t_maxrows)
 145                         new->t_minrows = new->t_maxrows;
 146         } else {
 147                 sp->t_minrows = sp->t_rows = IS_ONELINE(sp) ? 1 : sp->rows - 1;
 148
 149                 /*
 150                  * The new screen may be a small screen, even if the parent
 151                  * was not.  Don't complain if O_WINDOW is too large, we're
 152                  * splitting the screen so the screen is much smaller than
 153                  * normal.
 154                  */
 155                 new->t_minrows = new->t_rows = O_VAL(sp, O_WINDOW);
 156                 if (new->t_rows > new->rows - 1)
 157                         new->t_minrows = new->t_rows =
 158                             IS_ONELINE(new) ? 1 : new->rows - 1;
 159         }
 160
 161         /* Adjust the ends of the new and old maps. */
 162         _TMAP(sp) = IS_ONELINE(sp) ?
 163             _HMAP(sp) : _HMAP(sp) + (sp->t_rows - 1);
 164         _TMAP(new) = IS_ONELINE(new) ?
 165             _HMAP(new) : _HMAP(new) + (new->t_rows - 1);
 166
 167         /* Reset the length of the default scroll. */
 168         if ((sp->defscroll = sp->t_maxrows / 2) == 0)
 169                 sp->defscroll = 1;
 170         if ((new->defscroll = new->t_maxrows / 2) == 0)
 171                 new->defscroll = 1;
 172
 173         /* Fit the screen into the logical chain. */
 174         vs_insert(new);
 175
 176         /* Tell the display that we're splitting. */
 177         (void)gp->scr_split(sp, new);
 178
 179         /*
 180          * Initialize the screen flags:
 181          *
 182          * If we're in vi mode in one screen, we don't have to reinitialize.
 183          * This isn't just a cosmetic fix.  The path goes like this:
 184          *
 185          *      return into vi(), SC_SSWITCH set
 186          *      call vs_refresh() with SC_STATUS set
 187          *      call vs_resolve to display the status message
 188          *      call vs_refresh() because the SC_SCR_VI bit isn't set
 189          *
 190          * Things go downhill at this point.
 191          *
 192          * Draw the new screen from scratch, and add a status line.
 193          */
 194         F_SET(new,
 195             SC_SCR_REFORMAT | SC_STATUS |
 196             F_ISSET(sp, SC_EX | SC_VI | SC_SCR_VI | SC_SCR_EX));
 197         return (0);
 198 }
 199
 200 /*
 201  * vs_vsplit --
 202  *      Create a new screen, vertically.
 203  *
 204  * PUBLIC: int vs_vsplit __P((SCR *, SCR *));
 205  */
 206 int
 207 vs_vsplit(sp, new)
 208         SCR *sp, *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 = 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);
 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));
 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(sp)
 299         SCR *sp;
 300 {
 301         GS *gp;
 302         SCR *tsp;
 303
 304         gp = sp->gp;
 305
 306         /* Move past all screens with lower row numbers. */
 307         for (tsp = gp->dq.cqh_first;
 308             tsp != (void *)&gp->dq; tsp = tsp->q.cqe_next)
 309                 if (tsp->roff >= sp->roff)
 310                         break;
 311         /*
 312          * Move past all screens with the same row number and lower
 313          * column numbers.
 314          */
 315         for (; tsp != (void *)&gp->dq; tsp = tsp->q.cqe_next)
 316                 if (tsp->roff != sp->roff || tsp->coff > sp->coff)
 317                         break;
 318
 319         /*
 320          * If we reached the end, this screen goes there.  Otherwise,
 321          * put it before or after the screen where we stopped.
 322          */
 323         if (tsp == (void *)&gp->dq) {
 324                 CIRCLEQ_INSERT_TAIL(&gp->dq, sp, q);
 325         } else if (tsp->roff < sp->roff ||
 326             tsp->roff == sp->roff && tsp->coff < sp->coff) {
 327                 CIRCLEQ_INSERT_BEFORE(&gp->dq, tsp, sp, q);
 328         } else
 329                 CIRCLEQ_INSERT_AFTER(&gp->dq, tsp, sp, q);
 330 }
 331
 332 /*
 333  * vs_discard --
 334  *      Discard the screen, folding the real-estate into a related screen,
 335  *      if one exists, and return that screen.
 336  *
 337  * PUBLIC: int vs_discard __P((SCR *, SCR **));
 338  */
 339 int
 340 vs_discard(sp, spp)
 341         SCR *sp, **spp;
 342 {
 343         GS *gp;
 344         SCR *tsp, **lp, *list[100];
 345         jdir_t jdir;
 346
 347         gp = sp->gp;
 348
 349         /*
 350          * Save the old screen's cursor information.
 351          *
 352          * XXX
 353          * If called after file_end(), and the underlying file was a tmp
 354          * file, it may have gone away.
 355          */
 356         if (sp->frp != NULL) {
 357                 sp->frp->lno = sp->lno;
 358                 sp->frp->cno = sp->cno;
 359                 F_SET(sp->frp, FR_CURSORSET);
 360         }
 361
 362         /* If no other screens to join, we're done. */
 363         if (!IS_SPLIT(sp)) {
 364                 (void)gp->scr_discard(sp, NULL);
 365
 366                 if (spp != NULL)
 367                         *spp = NULL;
 368                 return (0);
 369         }
 370
 371         /*
 372          * Find a set of screens that cover one of the screen's borders.
 373          * Check the vertical axis first, for no particular reason.
 374          *
 375          * XXX
 376          * It's possible (I think?), to create a screen that shares no full
 377          * border with any other set of screens, so we can't discard it.  We
 378          * just complain at the user until they clean it up.
 379          */
 380         if (vs_join(sp, list, &jdir))
 381                 return (1);
 382
 383         /*
 384          * Modify the affected screens.  Redraw the modified screen(s) from
 385          * scratch, setting a status line.  If this is ever a performance
 386          * problem we could play games with the map, but I wrote that code
 387          * before and it was never clean or easy.
 388          *
 389          * Don't clean up the discarded screen's information.  If the screen
 390          * isn't exiting, we'll do the work when the user redisplays it.
 391          */
 392         switch (jdir) {
 393         case HORIZ_FOLLOW:
 394         case HORIZ_PRECEDE:
 395                 for (lp = &list[0]; (tsp = *lp) != NULL; ++lp) {
 396                         /*
 397                          * Small screens: see vs_refresh.c section 6a.  Adjust
 398                          * text line info, unless it's a small screen.
 399                          *
 400                          * Reset the length of the default scroll.
 401                          *
 402                          * Reset the map references.
 403                          */
 404                         tsp->rows += sp->rows;
 405                         if (!IS_SMALL(tsp))
 406                                 tsp->t_rows = tsp->t_minrows = tsp->rows - 1;
 407                         tsp->t_maxrows = tsp->rows - 1;
 408
 409                         tsp->defscroll = tsp->t_maxrows / 2;
 410
 411                         *(_HMAP(tsp) + (tsp->t_rows - 1)) = *_TMAP(tsp);
 412                         _TMAP(tsp) = _HMAP(tsp) + (tsp->t_rows - 1);
 413
 414                         switch (jdir) {
 415                         case HORIZ_FOLLOW:
 416                                 tsp->roff = sp->roff;
 417                                 vs_sm_fill(tsp, OOBLNO, P_TOP);
 418                                 break;
 419                         case HORIZ_PRECEDE:
 420                                 vs_sm_fill(tsp, OOBLNO, P_BOTTOM);
 421                                 break;
 422                         default:
 423                                 abort();
 424                         }
 425                         F_SET(tsp, SC_STATUS);
 426                 }
 427                 break;
 428         case VERT_FOLLOW:
 429         case VERT_PRECEDE:
 430                 for (lp = &list[0]; (tsp = *lp) != NULL; ++lp) {
 431                         if (jdir == VERT_FOLLOW)
 432                                 tsp->coff = sp->coff;
 433                         tsp->cols += sp->cols + 1;      /* XXX: DIVIDER */
 434                         vs_sm_fill(tsp, OOBLNO, P_TOP);
 435                         F_SET(tsp, SC_STATUS);
 436                 }
 437                 break;
 438         default:
 439                 abort();
 440         }
 441
 442         /* Find the closest screen that changed and move to it. */
 443         tsp = list[0];
 444         if (spp != NULL)
 445                 *spp = tsp;
 446
 447         /* Tell the display that we're discarding a screen. */
 448         (void)gp->scr_discard(sp, tsp);
 449
 450         return (0);
 451 }
 452
 453 /*
 454  * vs_join --
 455  *      Find a set of screens that covers a screen's border.
 456  */
 457 static int
 458 vs_join(sp, listp, jdirp)
 459         SCR *sp, **listp;
 460         jdir_t *jdirp;
 461 {
 462         GS *gp;
 463         SCR **lp, *tsp;
 464         int first;
 465         size_t tlen;
 466
 467         gp = sp->gp;
 468
 469         /* Check preceding vertical. */
 470         for (lp = listp, tlen = sp->rows,
 471             tsp = gp->dq.cqh_first;
 472             tsp != (void *)&gp->dq; tsp = tsp->q.cqe_next) {
 473                 if (sp == tsp)
 474                         continue;
 475                 /* Test if precedes the screen vertically. */
 476                 if (tsp->coff + tsp->cols + 1 != sp->coff)
 477                         continue;
 478                 /*
 479                  * Test if a subset on the vertical axis.  If overlaps the
 480                  * beginning or end, we can't join on this axis at all.
 481                  */
 482                 if (tsp->roff > sp->roff + sp->rows)
 483                         continue;
 484                 if (tsp->roff < sp->roff) {
 485                         if (tsp->roff + tsp->rows >= sp->roff)
 486                                 break;
 487                         continue;
 488                 }
 489                 if (tsp->roff + tsp->rows > sp->roff + sp->rows)
 490                         break;
 491 #ifdef DEBUG
 492                 if (tlen < tsp->rows)
 493                         abort();
 494 #endif
 495                 tlen -= tsp->rows;
 496                 *lp++ = tsp;
 497         }
 498         if (tlen == 0) {
 499                 *lp = NULL;
 500                 *jdirp = VERT_PRECEDE;
 501                 return (0);
 502         }
 503
 504         /* Check following vertical. */
 505         for (lp = listp, tlen = sp->rows,
 506             tsp = gp->dq.cqh_first;
 507             tsp != (void *)&gp->dq; tsp = tsp->q.cqe_next) {
 508                 if (sp == tsp)
 509                         continue;
 510                 /* Test if follows the screen vertically. */
 511                 if (tsp->coff != sp->coff + sp->cols + 1)
 512                         continue;
 513                 /*
 514                  * Test if a subset on the vertical axis.  If overlaps the
 515                  * beginning or end, we can't join on this axis at all.
 516                  */
 517                 if (tsp->roff > sp->roff + sp->rows)
 518                         continue;
 519                 if (tsp->roff < sp->roff) {
 520                         if (tsp->roff + tsp->rows >= sp->roff)
 521                                 break;
 522                         continue;
 523                 }
 524                 if (tsp->roff + tsp->rows > sp->roff + sp->rows)
 525                         break;
 526 #ifdef DEBUG
 527                 if (tlen < tsp->rows)
 528                         abort();
 529 #endif
 530                 tlen -= tsp->rows;
 531                 *lp++ = tsp;
 532         }
 533         if (tlen == 0) {
 534                 *lp = NULL;
 535                 *jdirp = VERT_FOLLOW;
 536                 return (0);
 537         }
 538
 539         /* Check preceding horizontal. */
 540         for (first = 0, lp = listp, tlen = sp->cols,
 541             tsp = gp->dq.cqh_first;
 542             tsp != (void *)&gp->dq; tsp = tsp->q.cqe_next) {
 543                 if (sp == tsp)
 544                         continue;
 545                 /* Test if precedes the screen horizontally. */
 546                 if (tsp->roff + tsp->rows != sp->roff)
 547                         continue;
 548                 /*
 549                  * Test if a subset on the horizontal axis.  If overlaps the
 550                  * beginning or end, we can't join on this axis at all.
 551                  */
 552                 if (tsp->coff > sp->coff + sp->cols)
 553                         continue;
 554                 if (tsp->coff < sp->coff) {
 555                         if (tsp->coff + tsp->cols >= sp->coff)
 556                                 break;
 557                         continue;
 558                 }
 559                 if (tsp->coff + tsp->cols > sp->coff + sp->cols)
 560                         break;
 561 #ifdef DEBUG
 562                 if (tlen < tsp->cols)
 563                         abort();
 564 #endif
 565                 tlen -= tsp->cols + first;
 566                 first = 1;
 567                 *lp++ = tsp;
 568         }
 569         if (tlen == 0) {
 570                 *lp = NULL;
 571                 *jdirp = HORIZ_PRECEDE;
 572                 return (0);
 573         }
 574
 575         /* Check following horizontal. */
 576         for (first = 0, lp = listp, tlen = sp->cols,
 577             tsp = gp->dq.cqh_first;
 578             tsp != (void *)&gp->dq; tsp = tsp->q.cqe_next) {
 579                 if (sp == tsp)
 580                         continue;
 581                 /* Test if precedes the screen horizontally. */
 582                 if (tsp->roff != sp->roff + sp->rows)
 583                         continue;
 584                 /*
 585                  * Test if a subset on the horizontal axis.  If overlaps the
 586                  * beginning or end, we can't join on this axis at all.
 587                  */
 588                 if (tsp->coff > sp->coff + sp->cols)
 589                         continue;
 590                 if (tsp->coff < sp->coff) {
 591                         if (tsp->coff + tsp->cols >= sp->coff)
 592                                 break;
 593                         continue;
 594                 }
 595                 if (tsp->coff + tsp->cols > sp->coff + sp->cols)
 596                         break;
 597 #ifdef DEBUG
 598                 if (tlen < tsp->cols)
 599                         abort();
 600 #endif
 601                 tlen -= tsp->cols + first;
 602                 first = 1;
 603                 *lp++ = tsp;
 604         }
 605         if (tlen == 0) {
 606                 *lp = NULL;
 607                 *jdirp = HORIZ_FOLLOW;
 608                 return (0);
 609         }
 610         return (1);
 611 }
 612
 613 /*
 614  * vs_fg --
 615  *      Background the current screen, and foreground a new one.
 616  *
 617  * PUBLIC: int vs_fg __P((SCR *, SCR **, CHAR_T *, int));
 618  */
 619 int
 620 vs_fg(sp, nspp, name, newscreen)
 621         SCR *sp, **nspp;
 622         CHAR_T *name;
 623         int newscreen;
 624 {
 625         GS *gp;
 626         SCR *nsp;
 627
 628         gp = sp->gp;
 629
 630         if (newscreen)
 631                 /* Get the specified background screen. */
 632                 nsp = vs_getbg(sp, name);
 633         else
 634                 /* Swap screens. */
 635                 if (vs_swap(sp, &nsp, name))
 636                         return (1);
 637
 638         if ((*nspp = nsp) == NULL) {
 639                 msgq_str(sp, M_ERR, name,
 640                     name == NULL ?
 641                     "223|There are no background screens" :
 642                     "224|There's no background screen editing a file named %s");
 643                 return (1);
 644         }
 645
 646         if (newscreen) {
 647                 /* Remove the new screen from the background queue. */
 648                 CIRCLEQ_REMOVE(&gp->hq, nsp, q);
 649
 650                 /* Split the screen; if we fail, hook the screen back in. */
 651                 if (vs_split(sp, nsp, 0)) {
 652                         CIRCLEQ_INSERT_TAIL(&gp->hq, nsp, q);
 653                         return (1);
 654                 }
 655         } else {
 656                 /* Move the old screen to the background queue. */
 657                 CIRCLEQ_REMOVE(&gp->dq, sp, q);
 658                 CIRCLEQ_INSERT_TAIL(&gp->hq, sp, q);
 659         }
 660         return (0);
 661 }
 662
 663 /*
 664  * vs_bg --
 665  *      Background the screen, and switch to the next one.
 666  *
 667  * PUBLIC: int vs_bg __P((SCR *));
 668  */
 669 int
 670 vs_bg(sp)
 671         SCR *sp;
 672 {
 673         GS *gp;
 674         SCR *nsp;
 675
 676         gp = sp->gp;
 677
 678         /* Try and join with another screen. */
 679         if (vs_discard(sp, &nsp))
 680                 return (1);
 681         if (nsp == NULL) {
 682                 msgq(sp, M_ERR,
 683                     "225|You may not background your only displayed screen");
 684                 return (1);
 685         }
 686
 687         /* Move the old screen to the background queue. */
 688         CIRCLEQ_REMOVE(&gp->dq, sp, q);
 689         CIRCLEQ_INSERT_TAIL(&gp->hq, sp, q);
 690
 691         /* Toss the screen map. */
 692         free(_HMAP(sp));
 693         _HMAP(sp) = NULL;
 694
 695         /* Switch screens. */
 696         sp->nextdisp = nsp;
 697         F_SET(sp, SC_SSWITCH);
 698
 699         return (0);
 700 }
 701
 702 /*
 703  * vs_swap --
 704  *      Swap the current screen with a backgrounded one.
 705  *
 706  * PUBLIC: int vs_swap __P((SCR *, SCR **, char *));
 707  */
 708 int
 709 vs_swap(sp, nspp, name)
 710         SCR *sp, **nspp;
 711         char *name;
 712 {
 713         GS *gp;
 714         SCR *nsp;
 715
 716         gp = sp->gp;
 717
 718         /* Get the specified background screen. */
 719         if ((*nspp = nsp = vs_getbg(sp, name)) == NULL)
 720                 return (0);
 721
 722         /*
 723          * Save the old screen's cursor information.
 724          *
 725          * XXX
 726          * If called after file_end(), and the underlying file was a tmp
 727          * file, it may have gone away.
 728          */
 729         if (sp->frp != NULL) {
 730                 sp->frp->lno = sp->lno;
 731                 sp->frp->cno = sp->cno;
 732                 F_SET(sp->frp, FR_CURSORSET);
 733         }
 734
 735         /* Switch screens. */
 736         sp->nextdisp = nsp;
 737         F_SET(sp, SC_SSWITCH);
 738
 739         /* Initialize terminal information. */
 740         VIP(nsp)->srows = VIP(sp)->srows;
 741
 742         /* Initialize screen information. */
 743         nsp->cols = sp->cols;
 744         nsp->rows = sp->rows;   /* XXX: Only place in vi that sets rows. */
 745         nsp->roff = sp->roff;
 746
 747         /*
 748          * Small screens: see vs_refresh.c, section 6a.
 749          *
 750          * The new screens may have different screen options sizes than the
 751          * old one, so use them.  Make sure that text counts aren't larger
 752          * than the new screen sizes.
 753          */
 754         if (IS_SMALL(nsp)) {
 755                 nsp->t_minrows = nsp->t_rows = O_VAL(nsp, O_WINDOW);
 756                 if (nsp->t_rows > sp->t_maxrows)
 757                         nsp->t_rows = nsp->t_maxrows;
 758                 if (nsp->t_minrows > sp->t_maxrows)
 759                         nsp->t_minrows = nsp->t_maxrows;
 760         } else
 761                 nsp->t_rows = nsp->t_maxrows = nsp->t_minrows = nsp->rows - 1;
 762
 763         /* Reset the length of the default scroll. */
 764         nsp->defscroll = nsp->t_maxrows / 2;
 765
 766         /* Allocate a new screen map. */
 767         CALLOC_RET(nsp, _HMAP(nsp), SMAP *, SIZE_HMAP(nsp), sizeof(SMAP));
 768         _TMAP(nsp) = _HMAP(nsp) + (nsp->t_rows - 1);
 769
 770         /* Fill the map. */
 771         if (vs_sm_fill(nsp, nsp->lno, P_FILL))
 772                 return (1);
 773
 774         /*
 775          * The new screen replaces the old screen in the parent/child list.
 776          * We insert the new screen after the old one.  If we're exiting,
 777          * the exit will delete the old one, if we're foregrounding, the fg
 778          * code will move the old one to the background queue.
 779          */
 780         CIRCLEQ_REMOVE(&gp->hq, nsp, q);
 781         CIRCLEQ_INSERT_AFTER(&gp->dq, sp, nsp, q);
 782
 783         /*
 784          * Don't change the screen's cursor information other than to
 785          * note that the cursor is wrong.
 786          */
 787         F_SET(VIP(nsp), VIP_CUR_INVALID);
 788
 789         /* Draw the new screen from scratch, and add a status line. */
 790         F_SET(nsp, SC_SCR_REDRAW | SC_STATUS);
 791         return (0);
 792 }
 793
 794 /*
 795  * vs_resize --
 796  *      Change the absolute size of the current screen.
 797  *
 798  * PUBLIC: int vs_resize __P((SCR *, long, adj_t));
 799  */
 800 int
 801 vs_resize(sp, count, adj)
 802         SCR *sp;
 803         long count;
 804         adj_t adj;
 805 {
 806         GS *gp;
 807         SCR *g, *s;
 808         size_t g_off, s_off;
 809
 810         gp = sp->gp;
 811
 812         /*
 813          * Figure out which screens will grow, which will shrink, and
 814          * make sure it's possible.
 815          */
 816         if (count == 0)
 817                 return (0);
 818         if (adj == A_SET) {
 819                 if (sp->t_maxrows == count)
 820                         return (0);
 821                 if (sp->t_maxrows > count) {
 822                         adj = A_DECREASE;
 823                         count = sp->t_maxrows - count;
 824                 } else {
 825                         adj = A_INCREASE;
 826                         count = count - sp->t_maxrows;
 827                 }
 828         }
 829
 830         g_off = s_off = 0;
 831         if (adj == A_DECREASE) {
 832                 if (count < 0)
 833                         count = -count;
 834                 s = sp;
 835                 if (s->t_maxrows < MINIMUM_SCREEN_ROWS + count)
 836                         goto toosmall;
 837                 if ((g = sp->q.cqe_prev) == (void *)&gp->dq) {
 838                         if ((g = sp->q.cqe_next) == (void *)&gp->dq)
 839                                 goto toobig;
 840                         g_off = -count;
 841                 } else
 842                         s_off = count;
 843         } else {
 844                 g = sp;
 845                 if ((s = sp->q.cqe_next) != (void *)&gp->dq)
 846                         if (s->t_maxrows < MINIMUM_SCREEN_ROWS + count)
 847                                 s = NULL;
 848                         else
 849                                 s_off = count;
 850                 else
 851                         s = NULL;
 852                 if (s == NULL) {
 853                         if ((s = sp->q.cqe_prev) == (void *)&gp->dq) {
 854 toobig:                         msgq(sp, M_BERR, adj == A_DECREASE ?
 855                                     "227|The screen cannot shrink" :
 856                                     "228|The screen cannot grow");
 857                                 return (1);
 858                         }
 859                         if (s->t_maxrows < MINIMUM_SCREEN_ROWS + count) {
 860 toosmall:                       msgq(sp, M_BERR,
 861                                     "226|The screen can only shrink to %d rows",
 862                                     MINIMUM_SCREEN_ROWS);
 863                                 return (1);
 864                         }
 865                         g_off = -count;
 866                 }
 867         }
 868
 869         /*
 870          * Fix up the screens; we could optimize the reformatting of the
 871          * screen, but this isn't likely to be a common enough operation
 872          * to make it worthwhile.
 873          */
 874         s->rows += -count;
 875         s->roff += s_off;
 876         g->rows += count;
 877         g->roff += g_off;
 878
 879         g->t_rows += count;
 880         if (g->t_minrows == g->t_maxrows)
 881                 g->t_minrows += count;
 882         g->t_maxrows += count;
 883         _TMAP(g) += count;
 884         F_SET(g, SC_SCR_REFORMAT | SC_STATUS);
 885
 886         s->t_rows -= count;
 887         s->t_maxrows -= count;
 888         if (s->t_minrows > s->t_maxrows)
 889                 s->t_minrows = s->t_maxrows;
 890         _TMAP(s) -= count;
 891         F_SET(s, SC_SCR_REFORMAT | SC_STATUS);
 892
 893         return (0);
 894 }
 895
 896 /*
 897  * vs_getbg --
 898  *      Get the specified background screen, or, if name is NULL, the first
 899  *      background screen.
 900  */
 901 static SCR *
 902 vs_getbg(sp, name)
 903         SCR *sp;
 904         char *name;
 905 {
 906         GS *gp;
 907         SCR *nsp;
 908         char *p;
 909
 910         gp = sp->gp;
 911
 912         /* If name is NULL, return the first background screen on the list. */
 913         if (name == NULL) {
 914                 nsp = gp->hq.cqh_first;
 915                 return (nsp == (void *)&gp->hq ? NULL : nsp);
 916         }
 917
 918         /* Search for a full match. */
 919         for (nsp = gp->hq.cqh_first;
 920             nsp != (void *)&gp->hq; nsp = nsp->q.cqe_next)
 921                 if (!strcmp(nsp->frp->name, name))
 922                         break;
 923         if (nsp != (void *)&gp->hq)
 924                 return (nsp);
 925
 926         /* Search for a last-component match. */
 927         for (nsp = gp->hq.cqh_first;
 928             nsp != (void *)&gp->hq; nsp = nsp->q.cqe_next) {
 929                 if ((p = strrchr(nsp->frp->name, '/')) == NULL)
 930                         p = nsp->frp->name;
 931                 else
 932                         ++p;
 933                 if (!strcmp(p, name))
 934                         break;
 935         }
 936         if (nsp != (void *)&gp->hq)
 937                 return (nsp);
 938
 939         return (NULL);
 940 }