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 10.42 2001/06/25 15:19:38 skimo Exp $ (Berkeley) $Date: 2001/06/25 15:19:38 $";
  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 *sp, WIN *wp));
  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(SCR *sp, SCR *new, int ccl)
  44
  45                                 /* 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, sp->wp);
 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(SCR *sp, SCR *new)
 208 {
 209         GS *gp;
 210         size_t cols;
 211
 212         gp = sp->gp;
 213
 214         /* Check to see if it's possible. */
 215         if (sp->cols / 2 <= MINIMUM_SCREEN_COLS) {
 216                 msgq(sp, M_ERR,
 217                     "288|Screen must be larger than %d columns to split",
 218                     MINIMUM_SCREEN_COLS * 2);
 219                 return (1);
 220         }
 221
 222         /* Wait for any messages in the screen. */
 223         vs_resolve(sp, NULL, 1);
 224
 225         /* Get a new screen map. */
 226         CALLOC(sp, _HMAP(new), SMAP *, SIZE_HMAP(sp), sizeof(SMAP));
 227         if (_HMAP(new) == NULL)
 228                 return (1);
 229         _HMAP(new)->lno = sp->lno;
 230         _HMAP(new)->coff = 0;
 231         _HMAP(new)->soff = 1;
 232
 233         /*
 234          * Split the screen in half; we have to sacrifice a column to delimit
 235          * the screens.
 236          *
 237          * XXX
 238          * We always split to the right... that makes more sense to me, and
 239          * I don't want to play the stupid games that I play when splitting
 240          * horizontally.
 241          *
 242          * XXX
 243          * We reserve a column for the screen, "knowing" that curses needs
 244          * one.  This should be worked out with the display interface.
 245          */
 246         cols = sp->cols / 2;
 247         new->cols = sp->cols - cols - 1;
 248         sp->cols = cols;
 249         new->coff = sp->coff + cols + 1;
 250         sp->cno = 0;
 251
 252         /* Nothing else changes. */
 253         new->rows = sp->rows;
 254         new->t_rows = sp->t_rows;
 255         new->t_maxrows = sp->t_maxrows;
 256         new->t_minrows = sp->t_minrows;
 257         new->roff = sp->roff;
 258         new->defscroll = sp->defscroll;
 259         _TMAP(new) = _HMAP(new) + (new->t_rows - 1);
 260
 261         /* Fit the screen into the logical chain. */
 262         vs_insert(new, sp->wp);
 263
 264         /* Tell the display that we're splitting. */
 265         (void)gp->scr_split(sp, new);
 266
 267         /* Redraw the old screen from scratch. */
 268         F_SET(sp, SC_SCR_REFORMAT | SC_STATUS);
 269
 270         /*
 271          * Initialize the screen flags:
 272          *
 273          * If we're in vi mode in one screen, we don't have to reinitialize.
 274          * This isn't just a cosmetic fix.  The path goes like this:
 275          *
 276          *      return into vi(), SC_SSWITCH set
 277          *      call vs_refresh() with SC_STATUS set
 278          *      call vs_resolve to display the status message
 279          *      call vs_refresh() because the SC_SCR_VI bit isn't set
 280          *
 281          * Things go downhill at this point.
 282          *
 283          * Draw the new screen from scratch, and add a status line.
 284          */
 285         F_SET(new,
 286             SC_SCR_REFORMAT | SC_STATUS |
 287             F_ISSET(sp, SC_EX | SC_VI | SC_SCR_VI | SC_SCR_EX));
 288         return (0);
 289 }
 290
 291 /*
 292  * vs_insert --
 293  *      Insert the new screen into the correct place in the logical
 294  *      chain.
 295  */
 296 static void
 297 vs_insert(SCR *sp, WIN *wp)
 298 {
 299         GS *gp;
 300         SCR *tsp;
 301
 302         gp = sp->gp;
 303
 304         sp->wp = wp;
 305
 306         /* Move past all screens with lower row numbers. */
 307         for (tsp = wp->scrq.cqh_first;
 308             tsp != (void *)&wp->scrq; 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 *)&wp->scrq; 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 *)&wp->scrq) {
 324                 CIRCLEQ_INSERT_TAIL(&wp->scrq, sp, q);
 325         } else if (tsp->roff < sp->roff ||
 326             (tsp->roff == sp->roff && tsp->coff < sp->coff)) {
 327                 CIRCLEQ_INSERT_AFTER(&wp->scrq, tsp, sp, q);
 328         } else
 329                 CIRCLEQ_INSERT_BEFORE(&wp->scrq, 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(SCR *sp, SCR **spp)
 341 {
 342         GS *gp;
 343         SCR *tsp, **lp, *list[100];
 344         jdir_t jdir;
 345
 346         gp = sp->gp;
 347
 348         /*
 349          * Save the old screen's cursor information.
 350          *
 351          * XXX
 352          * If called after file_end(), and the underlying file was a tmp
 353          * file, it may have gone away.
 354          */
 355         if (sp->frp != NULL) {
 356                 sp->frp->lno = sp->lno;
 357                 sp->frp->cno = sp->cno;
 358                 F_SET(sp->frp, FR_CURSORSET);
 359         }
 360
 361         /* If no other screens to join, we're done. */
 362         if (!IS_SPLIT(sp)) {
 363                 (void)gp->scr_discard(sp, NULL);
 364
 365                 if (spp != NULL)
 366                         *spp = NULL;
 367                 return (0);
 368         }
 369
 370         /*
 371          * Find a set of screens that cover one of the screen's borders.
 372          * Check the vertical axis first, for no particular reason.
 373          *
 374          * XXX
 375          * It's possible (I think?), to create a screen that shares no full
 376          * border with any other set of screens, so we can't discard it.  We
 377          * just complain at the user until they clean it up.
 378          */
 379         if (vs_join(sp, list, &jdir))
 380                 return (1);
 381
 382         /*
 383          * Modify the affected screens.  Redraw the modified screen(s) from
 384          * scratch, setting a status line.  If this is ever a performance
 385          * problem we could play games with the map, but I wrote that code
 386          * before and it was never clean or easy.
 387          *
 388          * Don't clean up the discarded screen's information.  If the screen
 389          * isn't exiting, we'll do the work when the user redisplays it.
 390          */
 391         switch (jdir) {
 392         case HORIZ_FOLLOW:
 393         case HORIZ_PRECEDE:
 394                 for (lp = &list[0]; (tsp = *lp) != NULL; ++lp) {
 395                         /*
 396                          * Small screens: see vs_refresh.c section 6a.  Adjust
 397                          * text line info, unless it's a small screen.
 398                          *
 399                          * Reset the length of the default scroll.
 400                          *
 401                          * Reset the map references.
 402                          */
 403                         tsp->rows += sp->rows;
 404                         if (!IS_SMALL(tsp))
 405                                 tsp->t_rows = tsp->t_minrows = tsp->rows - 1;
 406                         tsp->t_maxrows = tsp->rows - 1;
 407
 408                         tsp->defscroll = tsp->t_maxrows / 2;
 409
 410                         *(_HMAP(tsp) + (tsp->t_rows - 1)) = *_TMAP(tsp);
 411                         _TMAP(tsp) = _HMAP(tsp) + (tsp->t_rows - 1);
 412
 413                         switch (jdir) {
 414                         case HORIZ_FOLLOW:
 415                                 tsp->roff = sp->roff;
 416                                 vs_sm_fill(tsp, OOBLNO, P_TOP);
 417                                 break;
 418                         case HORIZ_PRECEDE:
 419                                 vs_sm_fill(tsp, OOBLNO, P_BOTTOM);
 420                                 break;
 421                         default:
 422                                 abort();
 423                         }
 424                         F_SET(tsp, SC_STATUS);
 425                 }
 426                 break;
 427         case VERT_FOLLOW:
 428         case VERT_PRECEDE:
 429                 for (lp = &list[0]; (tsp = *lp) != NULL; ++lp) {
 430                         if (jdir == VERT_FOLLOW)
 431                                 tsp->coff = sp->coff;
 432                         tsp->cols += sp->cols + 1;      /* XXX: DIVIDER */
 433                         vs_sm_fill(tsp, OOBLNO, P_TOP);
 434                         F_SET(tsp, SC_STATUS);
 435                 }
 436                 break;
 437         default:
 438                 abort();
 439         }
 440
 441         /* Find the closest screen that changed and move to it. */
 442         tsp = list[0];
 443         if (spp != NULL)
 444                 *spp = tsp;
 445
 446         /* Tell the display that we're discarding a screen. */
 447         (void)gp->scr_discard(sp, list);
 448
 449         return (0);
 450 }
 451
 452 /*
 453  * vs_join --
 454  *      Find a set of screens that covers a screen's border.
 455  */
 456 static int
 457 vs_join(SCR *sp, SCR **listp, jdir_t *jdirp)
 458 {
 459         GS *gp;
 460         WIN *wp;
 461         SCR **lp, *tsp;
 462         int first;
 463         size_t tlen;
 464
 465         gp = sp->gp;
 466         wp = sp->wp;
 467
 468         /* Check preceding vertical. */
 469         for (lp = listp, tlen = sp->rows,
 470             tsp = wp->scrq.cqh_first;
 471             tsp != (void *)&wp->scrq; tsp = tsp->q.cqe_next) {
 472                 if (sp == tsp)
 473                         continue;
 474                 /* Test if precedes the screen vertically. */
 475                 if (tsp->coff + tsp->cols + 1 != sp->coff)
 476                         continue;
 477                 /*
 478                  * Test if a subset on the vertical axis.  If overlaps the
 479                  * beginning or end, we can't join on this axis at all.
 480                  */
 481                 if (tsp->roff > sp->roff + sp->rows)
 482                         continue;
 483                 if (tsp->roff < sp->roff) {
 484                         if (tsp->roff + tsp->rows >= sp->roff)
 485                                 break;
 486                         continue;
 487                 }
 488                 if (tsp->roff + tsp->rows > sp->roff + sp->rows)
 489                         break;
 490 #ifdef DEBUG
 491                 if (tlen < tsp->rows)
 492                         abort();
 493 #endif
 494                 tlen -= tsp->rows;
 495                 *lp++ = tsp;
 496         }
 497         if (tlen == 0) {
 498                 *lp = NULL;
 499                 *jdirp = VERT_PRECEDE;
 500                 return (0);
 501         }
 502
 503         /* Check following vertical. */
 504         for (lp = listp, tlen = sp->rows,
 505             tsp = wp->scrq.cqh_first;
 506             tsp != (void *)&wp->scrq; tsp = tsp->q.cqe_next) {
 507                 if (sp == tsp)
 508                         continue;
 509                 /* Test if follows the screen vertically. */
 510                 if (tsp->coff != sp->coff + sp->cols + 1)
 511                         continue;
 512                 /*
 513                  * Test if a subset on the vertical axis.  If overlaps the
 514                  * beginning or end, we can't join on this axis at all.
 515                  */
 516                 if (tsp->roff > sp->roff + sp->rows)
 517                         continue;
 518                 if (tsp->roff < sp->roff) {
 519                         if (tsp->roff + tsp->rows >= sp->roff)
 520                                 break;
 521                         continue;
 522                 }
 523                 if (tsp->roff + tsp->rows > sp->roff + sp->rows)
 524                         break;
 525 #ifdef DEBUG
 526                 if (tlen < tsp->rows)
 527                         abort();
 528 #endif
 529                 tlen -= tsp->rows;
 530                 *lp++ = tsp;
 531         }
 532         if (tlen == 0) {
 533                 *lp = NULL;
 534                 *jdirp = VERT_FOLLOW;
 535                 return (0);
 536         }
 537
 538         /* Check preceding horizontal. */
 539         for (first = 0, lp = listp, tlen = sp->cols,
 540             tsp = wp->scrq.cqh_first;
 541             tsp != (void *)&wp->scrq; tsp = tsp->q.cqe_next) {
 542                 if (sp == tsp)
 543                         continue;
 544                 /* Test if precedes the screen horizontally. */
 545                 if (tsp->roff + tsp->rows != sp->roff)
 546                         continue;
 547                 /*
 548                  * Test if a subset on the horizontal axis.  If overlaps the
 549                  * beginning or end, we can't join on this axis at all.
 550                  */
 551                 if (tsp->coff > sp->coff + sp->cols)
 552                         continue;
 553                 if (tsp->coff < sp->coff) {
 554                         if (tsp->coff + tsp->cols >= sp->coff)
 555                                 break;
 556                         continue;
 557                 }
 558                 if (tsp->coff + tsp->cols > sp->coff + sp->cols)
 559                         break;
 560 #ifdef DEBUG
 561                 if (tlen < tsp->cols)
 562                         abort();
 563 #endif
 564                 tlen -= tsp->cols + first;
 565                 first = 1;
 566                 *lp++ = tsp;
 567         }
 568         if (tlen == 0) {
 569                 *lp = NULL;
 570                 *jdirp = HORIZ_PRECEDE;
 571                 return (0);
 572         }
 573
 574         /* Check following horizontal. */
 575         for (first = 0, lp = listp, tlen = sp->cols,
 576             tsp = wp->scrq.cqh_first;
 577             tsp != (void *)&wp->scrq; tsp = tsp->q.cqe_next) {
 578                 if (sp == tsp)
 579                         continue;
 580                 /* Test if precedes the screen horizontally. */
 581                 if (tsp->roff != sp->roff + sp->rows)
 582                         continue;
 583                 /*
 584                  * Test if a subset on the horizontal axis.  If overlaps the
 585                  * beginning or end, we can't join on this axis at all.
 586                  */
 587                 if (tsp->coff > sp->coff + sp->cols)
 588                         continue;
 589                 if (tsp->coff < sp->coff) {
 590                         if (tsp->coff + tsp->cols >= sp->coff)
 591                                 break;
 592                         continue;
 593                 }
 594                 if (tsp->coff + tsp->cols > sp->coff + sp->cols)
 595                         break;
 596 #ifdef DEBUG
 597                 if (tlen < tsp->cols)
 598                         abort();
 599 #endif
 600                 tlen -= tsp->cols + first;
 601                 first = 1;
 602                 *lp++ = tsp;
 603         }
 604         if (tlen == 0) {
 605                 *lp = NULL;
 606                 *jdirp = HORIZ_FOLLOW;
 607                 return (0);
 608         }
 609         return (1);
 610 }
 611
 612 /*
 613  * vs_fg --
 614  *      Background the current screen, and foreground a new one.
 615  *
 616  * PUBLIC: int vs_fg __P((SCR *, SCR **, CHAR_T *, int));
 617  */
 618 int
 619 vs_fg(SCR *sp, SCR **nspp, CHAR_T *name, int newscreen)
 620 {
 621         GS *gp;
 622         WIN *wp;
 623         SCR *nsp;
 624         char *np;
 625         size_t nlen;
 626
 627         gp = sp->gp;
 628         wp = sp->wp;
 629
 630         if (name)
 631             INT2CHAR(sp, name, STRLEN(name) + 1, np, nlen);
 632         else
 633             np = NULL;
 634         if (newscreen)
 635                 /* Get the specified background screen. */
 636                 nsp = vs_getbg(sp, np);
 637         else
 638                 /* Swap screens. */
 639                 if (vs_swap(sp, &nsp, np))
 640                         return (1);
 641
 642         if ((*nspp = nsp) == NULL) {
 643                 msgq_wstr(sp, M_ERR, name,
 644                     name == NULL ?
 645                     "223|There are no background screens" :
 646                     "224|There's no background screen editing a file named %s");
 647                 return (1);
 648         }
 649
 650         if (newscreen) {
 651                 /* Remove the new screen from the background queue. */
 652                 CIRCLEQ_REMOVE(&gp->hq, nsp, q);
 653
 654                 /* Split the screen; if we fail, hook the screen back in. */
 655                 if (vs_split(sp, nsp, 0)) {
 656                         CIRCLEQ_INSERT_TAIL(&gp->hq, nsp, q);
 657                         return (1);
 658                 }
 659         } else {
 660                 /* Move the old screen to the background queue. */
 661                 CIRCLEQ_REMOVE(&wp->scrq, sp, q);
 662                 CIRCLEQ_INSERT_TAIL(&gp->hq, sp, q);
 663         }
 664         return (0);
 665 }
 666
 667 /*
 668  * vs_bg --
 669  *      Background the screen, and switch to the next one.
 670  *
 671  * PUBLIC: int vs_bg __P((SCR *));
 672  */
 673 int
 674 vs_bg(SCR *sp)
 675 {
 676         GS *gp;
 677         WIN *wp;
 678         SCR *nsp;
 679
 680         gp = sp->gp;
 681         wp = sp->wp;
 682
 683         /* Try and join with another screen. */
 684         if (vs_discard(sp, &nsp))
 685                 return (1);
 686         if (nsp == NULL) {
 687                 msgq(sp, M_ERR,
 688                     "225|You may not background your only displayed screen");
 689                 return (1);
 690         }
 691
 692         /* Move the old screen to the background queue. */
 693         CIRCLEQ_REMOVE(&wp->scrq, sp, q);
 694         CIRCLEQ_INSERT_TAIL(&gp->hq, sp, q);
 695
 696         /* Toss the screen map. */
 697         free(_HMAP(sp));
 698         _HMAP(sp) = NULL;
 699
 700         /* Switch screens. */
 701         sp->nextdisp = nsp;
 702         F_SET(sp, SC_SSWITCH);
 703
 704         return (0);
 705 }
 706
 707 /*
 708  * vs_swap --
 709  *      Swap the current screen with a backgrounded one.
 710  *
 711  * PUBLIC: int vs_swap __P((SCR *, SCR **, char *));
 712  */
 713 int
 714 vs_swap(SCR *sp, SCR **nspp, char *name)
 715 {
 716         GS *gp;
 717         WIN *wp;
 718         SCR *nsp, *list[2];
 719
 720         gp = sp->gp;
 721         wp = sp->wp;
 722
 723         /* Get the specified background screen. */
 724         if ((*nspp = nsp = vs_getbg(sp, name)) == NULL)
 725                 return (0);
 726
 727         /*
 728          * Save the old screen's cursor information.
 729          *
 730          * XXX
 731          * If called after file_end(), and the underlying file was a tmp
 732          * file, it may have gone away.
 733          */
 734         if (sp->frp != NULL) {
 735                 sp->frp->lno = sp->lno;
 736                 sp->frp->cno = sp->cno;
 737                 F_SET(sp->frp, FR_CURSORSET);
 738         }
 739
 740         /* Switch screens. */
 741         sp->nextdisp = nsp;
 742         F_SET(sp, SC_SSWITCH);
 743
 744         /* Initialize terminal information. */
 745         VIP(nsp)->srows = VIP(sp)->srows;
 746
 747         /* Initialize screen information. */
 748         nsp->cols = sp->cols;
 749         nsp->rows = sp->rows;   /* XXX: Only place in vi that sets rows. */
 750         nsp->roff = sp->roff;
 751
 752         /*
 753          * Small screens: see vs_refresh.c, section 6a.
 754          *
 755          * The new screens may have different screen options sizes than the
 756          * old one, so use them.  Make sure that text counts aren't larger
 757          * than the new screen sizes.
 758          */
 759         if (IS_SMALL(nsp)) {
 760                 nsp->t_minrows = nsp->t_rows = O_VAL(nsp, O_WINDOW);
 761                 if (nsp->t_rows > sp->t_maxrows)
 762                         nsp->t_rows = nsp->t_maxrows;
 763                 if (nsp->t_minrows > sp->t_maxrows)
 764                         nsp->t_minrows = nsp->t_maxrows;
 765         } else
 766                 nsp->t_rows = nsp->t_maxrows = nsp->t_minrows = nsp->rows - 1;
 767
 768         /* Reset the length of the default scroll. */
 769         nsp->defscroll = nsp->t_maxrows / 2;
 770
 771         /* Allocate a new screen map. */
 772         CALLOC_RET(nsp, _HMAP(nsp), SMAP *, SIZE_HMAP(nsp), sizeof(SMAP));
 773         _TMAP(nsp) = _HMAP(nsp) + (nsp->t_rows - 1);
 774
 775         /* Fill the map. */
 776         nsp->wp = sp->wp;
 777         if (vs_sm_fill(nsp, nsp->lno, P_FILL))
 778                 return (1);
 779
 780         /*
 781          * The new screen replaces the old screen in the parent/child list.
 782          * We insert the new screen after the old one.  If we're exiting,
 783          * the exit will delete the old one, if we're foregrounding, the fg
 784          * code will move the old one to the background queue.
 785          */
 786         CIRCLEQ_REMOVE(&gp->hq, nsp, q);
 787         CIRCLEQ_INSERT_AFTER(&wp->scrq, sp, nsp, q);
 788
 789         /*
 790          * Don't change the screen's cursor information other than to
 791          * note that the cursor is wrong.
 792          */
 793         F_SET(VIP(nsp), VIP_CUR_INVALID);
 794
 795         /* Draw the new screen from scratch, and add a status line. */
 796         F_SET(nsp, SC_SCR_REDRAW | SC_STATUS);
 797
 798         list[0] = nsp; list[1] = NULL;
 799         (void)gp->scr_discard(sp, list);
 800
 801         return (0);
 802 }
 803
 804 /*
 805  * vs_resize --
 806  *      Change the absolute size of the current screen.
 807  *
 808  * PUBLIC: int vs_resize __P((SCR *, long, adj_t));
 809  */
 810 int
 811 vs_resize(SCR *sp, long int count, adj_t adj)
 812 {
 813         GS *gp;
 814         WIN *wp;
 815         SCR *g, *s, *prev, *next, *list[3] = {NULL, NULL, NULL};
 816         size_t g_off, s_off;
 817
 818         gp = sp->gp;
 819         wp = sp->wp;
 820
 821         /*
 822          * Figure out which screens will grow, which will shrink, and
 823          * make sure it's possible.
 824          */
 825         if (count == 0)
 826                 return (0);
 827         if (adj == A_SET) {
 828                 if (sp->t_maxrows == count)
 829                         return (0);
 830                 if (sp->t_maxrows > count) {
 831                         adj = A_DECREASE;
 832                         count = sp->t_maxrows - count;
 833                 } else {
 834                         adj = A_INCREASE;
 835                         count = count - sp->t_maxrows;
 836                 }
 837         }
 838
 839         /* Find first overlapping screen */
 840         for (next = sp->q.cqe_next;
 841              next != (void *)&wp->scrq &&
 842              (next->coff >= sp->coff + sp->cols ||
 843               next->coff + next->cols <= sp->coff);
 844              next = next->q.cqe_next);
 845         /* See if we can use it */
 846         if (next != (void *)&wp->scrq &&
 847             (sp->coff != next->coff || sp->cols != next->cols))
 848                 next = (void *)&wp->scrq;
 849         for (prev = sp->q.cqe_prev;
 850              prev != (void *)&wp->scrq &&
 851              (prev->coff >= sp->coff + sp->cols ||
 852               prev->coff + prev->cols <= sp->coff);
 853              prev = prev->q.cqe_prev);
 854         if (prev != (void *)&wp->scrq &&
 855             (sp->coff != prev->coff || sp->cols != prev->cols))
 856                 prev = (void *)&wp->scrq;
 857
 858         g_off = s_off = 0;
 859         if (adj == A_DECREASE) {
 860                 if (count < 0)
 861                         count = -count;
 862                 s = sp;
 863                 if (s->t_maxrows < MINIMUM_SCREEN_ROWS + count)
 864                         goto toosmall;
 865                 if ((g = prev) == (void *)&wp->scrq) {
 866                         if ((g = next) == (void *)&wp->scrq)
 867                                 goto toobig;
 868                         g_off = -count;
 869                 } else
 870                         s_off = count;
 871         } else {
 872                 g = sp;
 873                 if ((s = next) != (void *)&wp->scrq &&
 874                     s->t_maxrows >= MINIMUM_SCREEN_ROWS + count)
 875                                 s_off = count;
 876                 else
 877                         s = NULL;
 878                 if (s == NULL) {
 879                         if ((s = prev) == (void *)&wp->scrq) {
 880 toobig:                         msgq(sp, M_BERR, adj == A_DECREASE ?
 881                                     "227|The screen cannot shrink" :
 882                                     "228|The screen cannot grow");
 883                                 return (1);
 884                         }
 885                         if (s->t_maxrows < MINIMUM_SCREEN_ROWS + count) {
 886 toosmall:                       msgq(sp, M_BERR,
 887                                     "226|The screen can only shrink to %d rows",
 888                                     MINIMUM_SCREEN_ROWS);
 889                                 return (1);
 890                         }
 891                         g_off = -count;
 892                 }
 893         }
 894
 895         /*
 896          * Fix up the screens; we could optimize the reformatting of the
 897          * screen, but this isn't likely to be a common enough operation
 898          * to make it worthwhile.
 899          */
 900         s->rows += -count;
 901         s->roff += s_off;
 902         g->rows += count;
 903         g->roff += g_off;
 904
 905         g->t_rows += count;
 906         if (g->t_minrows == g->t_maxrows)
 907                 g->t_minrows += count;
 908         g->t_maxrows += count;
 909         _TMAP(g) += count;
 910         F_SET(g, SC_SCR_REFORMAT | SC_STATUS);
 911
 912         s->t_rows -= count;
 913         s->t_maxrows -= count;
 914         if (s->t_minrows > s->t_maxrows)
 915                 s->t_minrows = s->t_maxrows;
 916         _TMAP(s) -= count;
 917         F_SET(s, SC_SCR_REFORMAT | SC_STATUS);
 918
 919         /* XXXX */
 920         list[0] = g; list[1] = s;
 921         gp->scr_discard(0, list);
 922
 923         return (0);
 924 }
 925
 926 /*
 927  * vs_getbg --
 928  *      Get the specified background screen, or, if name is NULL, the first
 929  *      background screen.
 930  */
 931 static SCR *
 932 vs_getbg(SCR *sp, char *name)
 933 {
 934         GS *gp;
 935         SCR *nsp;
 936         char *p;
 937
 938         gp = sp->gp;
 939
 940         /* If name is NULL, return the first background screen on the list. */
 941         if (name == NULL) {
 942                 nsp = gp->hq.cqh_first;
 943                 return (nsp == (void *)&gp->hq ? NULL : nsp);
 944         }
 945
 946         /* Search for a full match. */
 947         for (nsp = gp->hq.cqh_first;
 948             nsp != (void *)&gp->hq; nsp = nsp->q.cqe_next)
 949                 if (!strcmp(nsp->frp->name, name))
 950                         break;
 951         if (nsp != (void *)&gp->hq)
 952                 return (nsp);
 953
 954         /* Search for a last-component match. */
 955         for (nsp = gp->hq.cqh_first;
 956             nsp != (void *)&gp->hq; nsp = nsp->q.cqe_next) {
 957                 if ((p = strrchr(nsp->frp->name, '/')) == NULL)
 958                         p = nsp->frp->name;
 959                 else
 960                         ++p;
 961                 if (!strcmp(p, name))
 962                         break;
 963         }
 964         if (nsp != (void *)&gp->hq)
 965                 return (nsp);
 966
 967         return (NULL);
 968 }