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