vi/vs_smap.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_smap.c,v 10.30 2002/01/19 21:59:07 skimo Exp $ (Berkeley) $Date: 2002/01/19 21:59:07 $";
  14 #endif /* not lint */
  15
  16 #include <sys/types.h>
  17 #include <sys/queue.h>
  18 #include <sys/time.h>
  19
  20 #include <bitstring.h>
  21 #include <limits.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include "../common/common.h"
  27 #include "vi.h"
  28
  29 static int      vs_deleteln __P((SCR *, int));
  30 static int      vs_insertln __P((SCR *, int));
  31 static int      vs_sm_delete __P((SCR *, db_recno_t));
  32 static int      vs_sm_down __P((SCR *, MARK *, db_recno_t, scroll_t, SMAP *));
  33 static int      vs_sm_erase __P((SCR *));
  34 static int      vs_sm_insert __P((SCR *, db_recno_t));
  35 static int      vs_sm_reset __P((SCR *, db_recno_t));
  36 static int      vs_sm_up __P((SCR *, MARK *, db_recno_t, scroll_t, SMAP *));
  37
  38 /*
  39  * vs_change --
  40  *      Make a change to the screen.
  41  *
  42  * PUBLIC: int vs_change __P((SCR *, db_recno_t, lnop_t));
  43  */
  44 int
  45 vs_change(SCR *sp, db_recno_t lno, lnop_t op)
  46 {
  47         VI_PRIVATE *vip;
  48         SMAP *p;
  49         size_t cnt, oldy, oldx;
  50
  51         vip = VIP(sp);
  52
  53         /*
  54          * XXX
  55          * Very nasty special case.  The historic vi code displays a single
  56          * space (or a '$' if the list option is set) for the first line in
  57          * an "empty" file.  If we "insert" a line, that line gets scrolled
  58          * down, not repainted, so it's incorrect when we refresh the screen.
  59          * The vi text input functions detect it explicitly and don't insert
  60          * a new line.
  61          *
  62          * Check for line #2 before going to the end of the file.
  63          */
  64         if (((op == LINE_APPEND && lno == 0) ||
  65             (op == LINE_INSERT && lno == 1)) &&
  66             !db_exist(sp, 2)) {
  67                 lno = 1;
  68                 op = LINE_RESET;
  69         }
  70
  71         /* Appending is the same as inserting, if the line is incremented. */
  72         if (op == LINE_APPEND) {
  73                 ++lno;
  74                 op = LINE_INSERT;
  75         }
  76
  77         /* Ignore the change if the line is after the map. */
  78         if (lno > TMAP->lno)
  79                 return (0);
  80
  81         /*
  82          * If the line is before the map, and it's a decrement, decrement
  83          * the map.  If it's an increment, increment the map.  Otherwise,
  84          * ignore it.
  85          */
  86         if (lno < HMAP->lno) {
  87                 switch (op) {
  88                 case LINE_APPEND:
  89                         abort();
  90                         /* NOTREACHED */
  91                 case LINE_DELETE:
  92                         for (p = HMAP, cnt = sp->t_rows; cnt--; ++p)
  93                                 --p->lno;
  94                         if (sp->lno >= lno)
  95                                 --sp->lno;
  96                         F_SET(vip, VIP_N_RENUMBER);
  97                         break;
  98                 case LINE_INSERT:
  99                         for (p = HMAP, cnt = sp->t_rows; cnt--; ++p)
 100                                 ++p->lno;
 101                         if (sp->lno >= lno)
 102                                 ++sp->lno;
 103                         F_SET(vip, VIP_N_RENUMBER);
 104                         break;
 105                 case LINE_RESET:
 106                         break;
 107                 }
 108                 return (0);
 109         }
 110
 111         F_SET(vip, VIP_N_REFRESH);
 112
 113         /*
 114          * Invalidate the line size cache, and invalidate the cursor if it's
 115          * on this line,
 116          */
 117         VI_SCR_CFLUSH(vip);
 118         if (sp->lno == lno)
 119                 F_SET(vip, VIP_CUR_INVALID);
 120
 121         /*
 122          * If ex modifies the screen after ex output is already on the screen
 123          * or if we've switched into ex canonical mode, don't touch it -- we'll
 124          * get scrolling wrong, at best.
 125          */
 126         if (!F_ISSET(sp, SC_TINPUT_INFO) &&
 127             (F_ISSET(sp, SC_SCR_EXWROTE) || VIP(sp)->totalcount > 1)) {
 128                 F_SET(vip, VIP_N_EX_REDRAW);
 129                 return (0);
 130         }
 131
 132         /* Save and restore the cursor for these routines. */
 133         (void)sp->gp->scr_cursor(sp, &oldy, &oldx);
 134
 135         switch (op) {
 136         case LINE_DELETE:
 137                 if (vs_sm_delete(sp, lno))
 138                         return (1);
 139                 if (sp->lno > lno)
 140                         --sp->lno;
 141                 F_SET(vip, VIP_N_RENUMBER);
 142                 break;
 143         case LINE_INSERT:
 144                 if (vs_sm_insert(sp, lno))
 145                         return (1);
 146                 if (sp->lno > lno)
 147                         ++sp->lno;
 148                 F_SET(vip, VIP_N_RENUMBER);
 149                 break;
 150         case LINE_RESET:
 151                 if (vs_sm_reset(sp, lno))
 152                         return (1);
 153                 break;
 154         default:
 155                 abort();
 156         }
 157
 158         (void)sp->gp->scr_move(sp, oldy, oldx);
 159         return (0);
 160 }
 161
 162 /*
 163  * vs_sm_fill --
 164  *      Fill in the screen map, placing the specified line at the
 165  *      right position.  There isn't any way to tell if an SMAP
 166  *      entry has been filled in, so this routine had better be
 167  *      called with P_FILL set before anything else is done.
 168  *
 169  * !!!
 170  * Unexported interface: if lno is OOBLNO, P_TOP means that the HMAP
 171  * slot is already filled in, P_BOTTOM means that the TMAP slot is
 172  * already filled in, and we just finish up the job.
 173  *
 174  * PUBLIC: int vs_sm_fill __P((SCR *, db_recno_t, pos_t));
 175  */
 176 int
 177 vs_sm_fill(SCR *sp, db_recno_t lno, pos_t pos)
 178 {
 179         SMAP *p, tmp;
 180         size_t cnt;
 181
 182         /* Flush all cached information from the SMAP. */
 183         for (p = HMAP, cnt = sp->t_rows; cnt--; ++p)
 184                 SMAP_FLUSH(p);
 185
 186         /*
 187          * If the map is filled, the screen must be redrawn.
 188          *
 189          * XXX
 190          * This is a bug.  We should try and figure out if the desired line
 191          * is already in the map or close by -- scrolling the screen would
 192          * be a lot better than redrawing.
 193          */
 194         F_SET(sp, SC_SCR_REDRAW);
 195
 196         switch (pos) {
 197         case P_FILL:
 198                 tmp.lno = 1;
 199                 tmp.coff = 0;
 200                 tmp.soff = 1;
 201
 202                 /* See if less than half a screen from the top. */
 203                 if (vs_sm_nlines(sp,
 204                     &tmp, lno, HALFTEXT(sp)) <= HALFTEXT(sp)) {
 205                         lno = 1;
 206                         goto top;
 207                 }
 208
 209                 /* See if less than half a screen from the bottom. */
 210                 if (db_last(sp, &tmp.lno))
 211                         return (1);
 212                 tmp.coff = 0;
 213                 tmp.soff = vs_screens(sp, tmp.lno, NULL);
 214                 if (vs_sm_nlines(sp,
 215                     &tmp, lno, HALFTEXT(sp)) <= HALFTEXT(sp)) {
 216                         TMAP->lno = tmp.lno;
 217                         TMAP->coff = tmp.coff;
 218                         TMAP->soff = tmp.soff;
 219                         goto bottom;
 220                 }
 221                 goto middle;
 222         case P_TOP:
 223                 if (lno != OOBLNO) {
 224 top:                    HMAP->lno = lno;
 225                         HMAP->coff = 0;
 226                         HMAP->soff = 1;
 227                 } else {
 228                         /*
 229                          * If number of lines HMAP->lno (top line) spans
 230                          * changed due to, say reformatting, and now is
 231                          * fewer than HMAP->soff, reset so the line is
 232                          * redrawn at the top of the screen.
 233                          */
 234                         cnt = vs_screens(sp, HMAP->lno, NULL);
 235                         if (cnt < HMAP->soff)
 236                                 HMAP->soff = 1;
 237                 }
 238                 /* If we fail, just punt. */
 239                 for (p = HMAP, cnt = sp->t_rows; --cnt; ++p)
 240                         if (vs_sm_next(sp, p, p + 1))
 241                                 goto err;
 242                 break;
 243         case P_MIDDLE:
 244                 /* If we fail, guess that the file is too small. */
 245 middle:         p = HMAP + sp->t_rows / 2;
 246                 p->lno = lno;
 247                 p->coff = 0;
 248                 p->soff = 1;
 249                 for (; p > HMAP; --p)
 250                         if (vs_sm_prev(sp, p, p - 1)) {
 251                                 lno = 1;
 252                                 goto top;
 253                         }
 254
 255                 /* If we fail, just punt. */
 256                 p = HMAP + sp->t_rows / 2;
 257                 for (; p < TMAP; ++p)
 258                         if (vs_sm_next(sp, p, p + 1))
 259                                 goto err;
 260                 break;
 261         case P_BOTTOM:
 262                 if (lno != OOBLNO) {
 263                         TMAP->lno = lno;
 264                         TMAP->coff = 0;
 265                         TMAP->soff = vs_screens(sp, lno, NULL);
 266                 }
 267                 /* If we fail, guess that the file is too small. */
 268 bottom:         for (p = TMAP; p > HMAP; --p)
 269                         if (vs_sm_prev(sp, p, p - 1)) {
 270                                 lno = 1;
 271                                 goto top;
 272                         }
 273                 break;
 274         default:
 275                 abort();
 276         }
 277         return (0);
 278
 279         /*
 280          * Try and put *something* on the screen.  If this fails, we have a
 281          * serious hard error.
 282          */
 283 err:    HMAP->lno = 1;
 284         HMAP->coff = 0;
 285         HMAP->soff = 1;
 286         for (p = HMAP; p < TMAP; ++p)
 287                 if (vs_sm_next(sp, p, p + 1))
 288                         return (1);
 289         return (0);
 290 }
 291
 292 /*
 293  * For the routines vs_sm_reset, vs_sm_delete and vs_sm_insert: if the
 294  * screen contains only a single line (whether because the screen is small
 295  * or the line large), it gets fairly exciting.  Skip the fun, set a flag
 296  * so the screen map is refilled and the screen redrawn, and return.  This
 297  * is amazingly slow, but it's not clear that anyone will care.
 298  */
 299 #define HANDLE_WEIRDNESS(cnt) {                                         \
 300         if (cnt >= sp->t_rows) {                                        \
 301                 F_SET(sp, SC_SCR_REFORMAT);                             \
 302                 return (0);                                             \
 303         }                                                               \
 304 }
 305
 306 /*
 307  * vs_sm_delete --
 308  *      Delete a line out of the SMAP.
 309  */
 310 static int
 311 vs_sm_delete(SCR *sp, db_recno_t lno)
 312 {
 313         SMAP *p, *t;
 314         size_t cnt_orig;
 315
 316         /*
 317          * Find the line in the map, and count the number of screen lines
 318          * which display any part of the deleted line.
 319          */
 320         for (p = HMAP; p->lno != lno; ++p);
 321         if (O_ISSET(sp, O_LEFTRIGHT))
 322                 cnt_orig = 1;
 323         else
 324                 for (cnt_orig = 1, t = p + 1;
 325                     t <= TMAP && t->lno == lno; ++cnt_orig, ++t);
 326
 327         HANDLE_WEIRDNESS(cnt_orig);
 328
 329         /* Delete that many lines from the screen. */
 330         (void)sp->gp->scr_move(sp, p - HMAP, 0);
 331         if (vs_deleteln(sp, cnt_orig))
 332                 return (1);
 333
 334         /* Shift the screen map up. */
 335         memmove(p, p + cnt_orig, (((TMAP - p) - cnt_orig) + 1) * sizeof(SMAP));
 336
 337         /* Decrement the line numbers for the rest of the map. */
 338         for (t = TMAP - cnt_orig; p <= t; ++p)
 339                 --p->lno;
 340
 341         /* Display the new lines. */
 342         for (p = TMAP - cnt_orig;;) {
 343                 if (p < TMAP && vs_sm_next(sp, p, p + 1))
 344                         return (1);
 345                 /* vs_sm_next() flushed the cache. */
 346                 if (vs_line(sp, ++p, NULL, NULL))
 347                         return (1);
 348                 if (p == TMAP)
 349                         break;
 350         }
 351         return (0);
 352 }
 353
 354 /*
 355  * vs_sm_insert --
 356  *      Insert a line into the SMAP.
 357  */
 358 static int
 359 vs_sm_insert(SCR *sp, db_recno_t lno)
 360 {
 361         SMAP *p, *t;
 362         size_t cnt_orig, cnt, coff;
 363
 364         /* Save the offset. */
 365         coff = HMAP->coff;
 366
 367         /*
 368          * Find the line in the map, find out how many screen lines
 369          * needed to display the line.
 370          */
 371         for (p = HMAP; p->lno != lno; ++p);
 372
 373         cnt_orig = vs_screens(sp, lno, NULL);
 374         HANDLE_WEIRDNESS(cnt_orig);
 375
 376         /*
 377          * The lines left in the screen override the number of screen
 378          * lines in the inserted line.
 379          */
 380         cnt = (TMAP - p) + 1;
 381         if (cnt_orig > cnt)
 382                 cnt_orig = cnt;
 383
 384         /* Push down that many lines. */
 385         (void)sp->gp->scr_move(sp, p - HMAP, 0);
 386         if (vs_insertln(sp, cnt_orig))
 387                 return (1);
 388
 389         /* Shift the screen map down. */
 390         memmove(p + cnt_orig, p, (((TMAP - p) - cnt_orig) + 1) * sizeof(SMAP));
 391
 392         /* Increment the line numbers for the rest of the map. */
 393         for (t = p + cnt_orig; t <= TMAP; ++t)
 394                 ++t->lno;
 395
 396         /* Fill in the SMAP for the new lines, and display. */
 397         for (cnt = 1, t = p; cnt <= cnt_orig; ++t, ++cnt) {
 398                 t->lno = lno;
 399                 t->coff = coff;
 400                 t->soff = cnt;
 401                 SMAP_FLUSH(t);
 402                 if (vs_line(sp, t, NULL, NULL))
 403                         return (1);
 404         }
 405         return (0);
 406 }
 407
 408 /*
 409  * vs_sm_reset --
 410  *      Reset a line in the SMAP.
 411  */
 412 static int
 413 vs_sm_reset(SCR *sp, db_recno_t lno)
 414 {
 415         SMAP *p, *t;
 416         size_t cnt_orig, cnt_new, cnt, diff;
 417
 418         /*
 419          * See if the number of on-screen rows taken up by the old display
 420          * for the line is the same as the number needed for the new one.
 421          * If so, repaint, otherwise do it the hard way.
 422          */
 423         for (p = HMAP; p->lno != lno; ++p);
 424         if (O_ISSET(sp, O_LEFTRIGHT)) {
 425                 t = p;
 426                 cnt_orig = cnt_new = 1;
 427         } else {
 428                 for (cnt_orig = 0,
 429                     t = p; t <= TMAP && t->lno == lno; ++cnt_orig, ++t);
 430                 cnt_new = vs_screens(sp, lno, NULL);
 431         }
 432
 433         HANDLE_WEIRDNESS(cnt_orig);
 434
 435         if (cnt_orig == cnt_new) {
 436                 do {
 437                         SMAP_FLUSH(p);
 438                         if (vs_line(sp, p, NULL, NULL))
 439                                 return (1);
 440                 } while (++p < t);
 441                 return (0);
 442         }
 443
 444         if (cnt_orig < cnt_new) {
 445                 /* Get the difference. */
 446                 diff = cnt_new - cnt_orig;
 447
 448                 /*
 449                  * The lines left in the screen override the number of screen
 450                  * lines in the inserted line.
 451                  */
 452                 cnt = (TMAP - p) + 1;
 453                 if (diff > cnt)
 454                         diff = cnt;
 455
 456                 /* If there are any following lines, push them down. */
 457                 if (cnt > 1) {
 458                         (void)sp->gp->scr_move(sp, p - HMAP, 0);
 459                         if (vs_insertln(sp, diff))
 460                                 return (1);
 461
 462                         /* Shift the screen map down. */
 463                         memmove(p + diff, p,
 464                             (((TMAP - p) - diff) + 1) * sizeof(SMAP));
 465                 }
 466
 467                 /* Fill in the SMAP for the replaced line, and display. */
 468                 for (cnt = 1, t = p; cnt_new-- && t <= TMAP; ++t, ++cnt) {
 469                         t->lno = lno;
 470                         t->soff = cnt;
 471                         SMAP_FLUSH(t);
 472                         if (vs_line(sp, t, NULL, NULL))
 473                                 return (1);
 474                 }
 475         } else {
 476                 /* Get the difference. */
 477                 diff = cnt_orig - cnt_new;
 478
 479                 /* Delete that many lines from the screen. */
 480                 (void)sp->gp->scr_move(sp, p - HMAP, 0);
 481                 if (vs_deleteln(sp, diff))
 482                         return (1);
 483
 484                 /* Shift the screen map up. */
 485                 memmove(p, p + diff, (((TMAP - p) - diff) + 1) * sizeof(SMAP));
 486
 487                 /* Fill in the SMAP for the replaced line, and display. */
 488                 for (cnt = 1, t = p; cnt_new--; ++t, ++cnt) {
 489                         t->lno = lno;
 490                         t->soff = cnt;
 491                         SMAP_FLUSH(t);
 492                         if (vs_line(sp, t, NULL, NULL))
 493                                 return (1);
 494                 }
 495
 496                 /* Display the new lines at the bottom of the screen. */
 497                 for (t = TMAP - diff;;) {
 498                         if (t < TMAP && vs_sm_next(sp, t, t + 1))
 499                                 return (1);
 500                         /* vs_sm_next() flushed the cache. */
 501                         if (vs_line(sp, ++t, NULL, NULL))
 502                                 return (1);
 503                         if (t == TMAP)
 504                                 break;
 505                 }
 506         }
 507         return (0);
 508 }
 509
 510 /*
 511  * vs_sm_scroll
 512  *      Scroll the SMAP up/down count logical lines.  Different
 513  *      semantics based on the vi command, *sigh*.
 514  *
 515  * PUBLIC: int vs_sm_scroll __P((SCR *, MARK *, db_recno_t, scroll_t));
 516  */
 517 int
 518 vs_sm_scroll(SCR *sp, MARK *rp, db_recno_t count, scroll_t scmd)
 519 {
 520         SMAP *smp;
 521
 522         /*
 523          * Invalidate the cursor.  The line is probably going to change,
 524          * (although for ^E and ^Y it may not).  In any case, the scroll
 525          * routines move the cursor to draw things.
 526          */
 527         F_SET(VIP(sp), VIP_CUR_INVALID);
 528
 529         /* Find the cursor in the screen. */
 530         if (vs_sm_cursor(sp, &smp))
 531                 return (1);
 532
 533         switch (scmd) {
 534         case CNTRL_B:
 535         case CNTRL_U:
 536         case CNTRL_Y:
 537         case Z_CARAT:
 538                 if (vs_sm_down(sp, rp, count, scmd, smp))
 539                         return (1);
 540                 break;
 541         case CNTRL_D:
 542         case CNTRL_E:
 543         case CNTRL_F:
 544         case Z_PLUS:
 545                 if (vs_sm_up(sp, rp, count, scmd, smp))
 546                         return (1);
 547                 break;
 548         default:
 549                 abort();
 550         }
 551
 552         /*
 553          * !!!
 554          * If we're at the start of a line, go for the first non-blank.
 555          * This makes it look like the old vi, even though we're moving
 556          * around by logical lines, not physical ones.
 557          *
 558          * XXX
 559          * In the presence of a long line, which has more than a screen
 560          * width of leading spaces, this code can cause a cursor warp.
 561          * Live with it.
 562          */
 563         if (scmd != CNTRL_E && scmd != CNTRL_Y &&
 564             rp->cno == 0 && nonblank(sp, rp->lno, &rp->cno))
 565                 return (1);
 566
 567         return (0);
 568 }
 569
 570 /*
 571  * vs_sm_up --
 572  *      Scroll the SMAP up count logical lines.
 573  */
 574 static int
 575 vs_sm_up(SCR *sp, MARK *rp, db_recno_t count, scroll_t scmd, SMAP *smp)
 576 {
 577         int cursor_set, echanged, zset;
 578         SMAP *ssmp, s1, s2;
 579
 580         /*
 581          * Check to see if movement is possible.
 582          *
 583          * Get the line after the map.  If that line is a new one (and if
 584          * O_LEFTRIGHT option is set, this has to be true), and the next
 585          * line doesn't exist, and the cursor doesn't move, or the cursor
 586          * isn't even on the screen, or the cursor is already at the last
 587          * line in the map, it's an error.  If that test succeeded because
 588          * the cursor wasn't at the end of the map, test to see if the map
 589          * is mostly empty.
 590          */
 591         if (vs_sm_next(sp, TMAP, &s1))
 592                 return (1);
 593         if (s1.lno > TMAP->lno && !db_exist(sp, s1.lno)) {
 594                 if (scmd == CNTRL_E || scmd == Z_PLUS || smp == TMAP) {
 595                         v_eof(sp, NULL);
 596                         return (1);
 597                 }
 598                 if (vs_sm_next(sp, smp, &s1))
 599                         return (1);
 600                 if (s1.lno > smp->lno && !db_exist(sp, s1.lno)) {
 601                         v_eof(sp, NULL);
 602                         return (1);
 603                 }
 604         }
 605
 606         /*
 607          * Small screens: see vs_refresh.c section 6a.
 608          *
 609          * If it's a small screen, and the movement isn't larger than a
 610          * screen, i.e some context will remain, open up the screen and
 611          * display by scrolling.  In this case, the cursor moves down one
 612          * line for each line displayed.  Otherwise, erase/compress and
 613          * repaint, and move the cursor to the first line in the screen.
 614          * Note, the ^F command is always in the latter case, for historical
 615          * reasons.
 616          */
 617         cursor_set = 0;
 618         if (IS_SMALL(sp)) {
 619                 if (count >= sp->t_maxrows || scmd == CNTRL_F) {
 620                         s1 = TMAP[0];
 621                         if (vs_sm_erase(sp))
 622                                 return (1);
 623                         for (; count--; s1 = s2) {
 624                                 if (vs_sm_next(sp, &s1, &s2))
 625                                         return (1);
 626                                 if (s2.lno != s1.lno && !db_exist(sp, s2.lno))
 627                                         break;
 628                         }
 629                         TMAP[0] = s2;
 630                         if (vs_sm_fill(sp, OOBLNO, P_BOTTOM))
 631                                 return (1);
 632                         return (vs_sm_position(sp, rp, 0, P_TOP));
 633                 }
 634                 cursor_set = scmd == CNTRL_E || vs_sm_cursor(sp, &ssmp);
 635                 for (; count &&
 636                     sp->t_rows != sp->t_maxrows; --count, ++sp->t_rows) {
 637                         if (vs_sm_next(sp, TMAP, &s1))
 638                                 return (1);
 639                         if (TMAP->lno != s1.lno && !db_exist(sp, s1.lno))
 640                                 break;
 641                         *++TMAP = s1;
 642                         /* vs_sm_next() flushed the cache. */
 643                         if (vs_line(sp, TMAP, NULL, NULL))
 644                                 return (1);
 645
 646                         if (!cursor_set)
 647                                 ++ssmp;
 648                 }
 649                 if (!cursor_set) {
 650                         rp->lno = ssmp->lno;
 651                         rp->cno = ssmp->c_sboff;
 652                 }
 653                 if (count == 0)
 654                         return (0);
 655         }
 656
 657         for (echanged = zset = 0; count; --count) {
 658                 /* Decide what would show up on the screen. */
 659                 if (vs_sm_next(sp, TMAP, &s1))
 660                         return (1);
 661
 662                 /* If the line doesn't exist, we're done. */
 663                 if (TMAP->lno != s1.lno && !db_exist(sp, s1.lno))
 664                         break;
 665
 666                 /* Scroll the screen cursor up one logical line. */
 667                 if (vs_sm_1up(sp))
 668                         return (1);
 669                 switch (scmd) {
 670                 case CNTRL_E:
 671                         if (smp > HMAP)
 672                                 --smp;
 673                         else
 674                                 echanged = 1;
 675                         break;
 676                 case Z_PLUS:
 677                         if (zset) {
 678                                 if (smp > HMAP)
 679                                         --smp;
 680                         } else {
 681                                 smp = TMAP;
 682                                 zset = 1;
 683                         }
 684                         /* FALLTHROUGH */
 685                 default:
 686                         break;
 687                 }
 688         }
 689
 690         if (cursor_set)
 691                 return(0);
 692
 693         switch (scmd) {
 694         case CNTRL_E:
 695                 /*
 696                  * On a ^E that was forced to change lines, try and keep the
 697                  * cursor as close as possible to the last position, but also
 698                  * set it up so that the next "real" movement will return the
 699                  * cursor to the closest position to the last real movement.
 700                  */
 701                 if (echanged) {
 702                         rp->lno = smp->lno;
 703                         rp->cno = vs_colpos(sp, smp->lno,
 704                             (O_ISSET(sp, O_LEFTRIGHT) ?
 705                             smp->coff : (smp->soff - 1) * sp->cols) +
 706                             sp->rcm % sp->cols);
 707                 }
 708                 return (0);
 709         case CNTRL_F:
 710                 /*
 711                  * If there are more lines, the ^F command is positioned at
 712                  * the first line of the screen.
 713                  */
 714                 if (!count) {
 715                         smp = HMAP;
 716                         break;
 717                 }
 718                 /* FALLTHROUGH */
 719         case CNTRL_D:
 720                 /*
 721                  * The ^D and ^F commands move the cursor towards EOF
 722                  * if there are more lines to move.  Check to be sure
 723                  * the lines actually exist.  (They may not if the
 724                  * file is smaller than the screen.)
 725                  */
 726                 for (; count; --count, ++smp)
 727                         if (smp == TMAP || !db_exist(sp, smp[1].lno))
 728                                 break;
 729                 break;
 730         case Z_PLUS:
 731                  /* The z+ command moves the cursor to the first new line. */
 732                 break;
 733         default:
 734                 abort();
 735         }
 736
 737         if (!SMAP_CACHE(smp) && vs_line(sp, smp, NULL, NULL))
 738                 return (1);
 739         rp->lno = smp->lno;
 740         rp->cno = smp->c_scoff == 255 ? 0 : smp->c_sboff;
 741         return (0);
 742 }
 743
 744 /*
 745  * vs_sm_1up --
 746  *      Scroll the SMAP up one.
 747  *
 748  * PUBLIC: int vs_sm_1up __P((SCR *));
 749  */
 750 int
 751 vs_sm_1up(SCR *sp)
 752 {
 753         /*
 754          * Delete the top line of the screen.  Shift the screen map
 755          * up and display a new line at the bottom of the screen.
 756          */
 757         (void)sp->gp->scr_move(sp, 0, 0);
 758         if (vs_deleteln(sp, 1))
 759                 return (1);
 760
 761         /* One-line screens can fail. */
 762         if (IS_ONELINE(sp)) {
 763                 if (vs_sm_next(sp, TMAP, TMAP))
 764                         return (1);
 765         } else {
 766                 memmove(HMAP, HMAP + 1, (sp->rows - 1) * sizeof(SMAP));
 767                 if (vs_sm_next(sp, TMAP - 1, TMAP))
 768                         return (1);
 769         }
 770         /* vs_sm_next() flushed the cache. */
 771         return (vs_line(sp, TMAP, NULL, NULL));
 772 }
 773
 774 /*
 775  * vs_deleteln --
 776  *      Delete a line a la curses, make sure to put the information
 777  *      line and other screens back.
 778  */
 779 static int
 780 vs_deleteln(SCR *sp, int cnt)
 781 {
 782         GS *gp;
 783         size_t oldy, oldx;
 784
 785         gp = sp->gp;
 786
 787         /* If the screen is vertically split, we can't scroll it. */
 788         if (IS_VSPLIT(sp)) {
 789                 F_SET(sp, SC_SCR_REDRAW);
 790                 return (0);
 791         }
 792
 793         if (IS_ONELINE(sp))
 794                 (void)gp->scr_clrtoeol(sp);
 795         else {
 796                 (void)gp->scr_cursor(sp, &oldy, &oldx);
 797                 while (cnt--) {
 798                         (void)gp->scr_deleteln(sp);
 799                         (void)gp->scr_move(sp, LASTLINE(sp), 0);
 800                         (void)gp->scr_insertln(sp);
 801                         (void)gp->scr_move(sp, oldy, oldx);
 802                 }
 803         }
 804         return (0);
 805 }
 806
 807 /*
 808  * vs_sm_down --
 809  *      Scroll the SMAP down count logical lines.
 810  */
 811 static int
 812 vs_sm_down(SCR *sp, MARK *rp, db_recno_t count, scroll_t scmd, SMAP *smp)
 813 {
 814         SMAP *ssmp, s1, s2;
 815         int cursor_set, ychanged, zset;
 816
 817         /* Check to see if movement is possible. */
 818         if (HMAP->lno == 1 &&
 819             (O_ISSET(sp, O_LEFTRIGHT) || HMAP->soff == 1) &&
 820             (scmd == CNTRL_Y || scmd == Z_CARAT || smp == HMAP)) {
 821                 v_sof(sp, NULL);
 822                 return (1);
 823         }
 824
 825         /*
 826          * Small screens: see vs_refresh.c section 6a.
 827          *
 828          * If it's a small screen, and the movement isn't larger than a
 829          * screen, i.e some context will remain, open up the screen and
 830          * display by scrolling.  In this case, the cursor moves up one
 831          * line for each line displayed.  Otherwise, erase/compress and
 832          * repaint, and move the cursor to the first line in the screen.
 833          * Note, the ^B command is always in the latter case, for historical
 834          * reasons.
 835          */
 836         cursor_set = scmd == CNTRL_Y;
 837         if (IS_SMALL(sp)) {
 838                 if (count >= sp->t_maxrows || scmd == CNTRL_B) {
 839                         s1 = HMAP[0];
 840                         if (vs_sm_erase(sp))
 841                                 return (1);
 842                         for (; count--; s1 = s2) {
 843                                 if (vs_sm_prev(sp, &s1, &s2))
 844                                         return (1);
 845                                 if (s2.lno == 1 &&
 846                                     (O_ISSET(sp, O_LEFTRIGHT) || s2.soff == 1))
 847                                         break;
 848                         }
 849                         HMAP[0] = s2;
 850                         if (vs_sm_fill(sp, OOBLNO, P_TOP))
 851                                 return (1);
 852                         return (vs_sm_position(sp, rp, 0, P_BOTTOM));
 853                 }
 854                 cursor_set = scmd == CNTRL_Y || vs_sm_cursor(sp, &ssmp);
 855                 for (; count &&
 856                     sp->t_rows != sp->t_maxrows; --count, ++sp->t_rows) {
 857                         if (HMAP->lno == 1 &&
 858                             (O_ISSET(sp, O_LEFTRIGHT) || HMAP->soff == 1))
 859                                 break;
 860                         ++TMAP;
 861                         if (vs_sm_1down(sp))
 862                                 return (1);
 863                 }
 864                 if (!cursor_set) {
 865                         rp->lno = ssmp->lno;
 866                         rp->cno = ssmp->c_sboff;
 867                 }
 868                 if (count == 0)
 869                         return (0);
 870         }
 871
 872         for (ychanged = zset = 0; count; --count) {
 873                 /* If the line doesn't exist, we're done. */
 874                 if (HMAP->lno == 1 &&
 875                     (O_ISSET(sp, O_LEFTRIGHT) || HMAP->soff == 1))
 876                         break;
 877
 878                 /* Scroll the screen and cursor down one logical line. */
 879                 if (vs_sm_1down(sp))
 880                         return (1);
 881                 switch (scmd) {
 882                 case CNTRL_Y:
 883                         if (smp < TMAP)
 884                                 ++smp;
 885                         else
 886                                 ychanged = 1;
 887                         break;
 888                 case Z_CARAT:
 889                         if (zset) {
 890                                 if (smp < TMAP)
 891                                         ++smp;
 892                         } else {
 893                                 smp = HMAP;
 894                                 zset = 1;
 895                         }
 896                         /* FALLTHROUGH */
 897                 default:
 898                         break;
 899                 }
 900         }
 901
 902         if (scmd != CNTRL_Y && cursor_set)
 903                 return(0);
 904
 905         switch (scmd) {
 906         case CNTRL_B:
 907                 /*
 908                  * If there are more lines, the ^B command is positioned at
 909                  * the last line of the screen.  However, the line may not
 910                  * exist.
 911                  */
 912                 if (!count) {
 913                         for (smp = TMAP; smp > HMAP; --smp)
 914                                 if (db_exist(sp, smp->lno))
 915                                         break;
 916                         break;
 917                 }
 918                 /* FALLTHROUGH */
 919         case CNTRL_U:
 920                 /*
 921                  * The ^B and ^U commands move the cursor towards SOF
 922                  * if there are more lines to move.
 923                  */
 924                 if (count < smp - HMAP)
 925                         smp -= count;
 926                 else
 927                         smp = HMAP;
 928                 break;
 929         case CNTRL_Y:
 930                 /*
 931                  * On a ^Y that was forced to change lines, try and keep the
 932                  * cursor as close as possible to the last position, but also
 933                  * set it up so that the next "real" movement will return the
 934                  * cursor to the closest position to the last real movement.
 935                  */
 936                 if (ychanged) {
 937                         rp->lno = smp->lno;
 938                         rp->cno = vs_colpos(sp, smp->lno,
 939                             (O_ISSET(sp, O_LEFTRIGHT) ?
 940                             smp->coff : (smp->soff - 1) * sp->cols) +
 941                             sp->rcm % sp->cols);
 942                 }
 943                 return (0);
 944         case Z_CARAT:
 945                  /* The z^ command moves the cursor to the first new line. */
 946                 break;
 947         default:
 948                 abort();
 949         }
 950
 951         if (!SMAP_CACHE(smp) && vs_line(sp, smp, NULL, NULL))
 952                 return (1);
 953         rp->lno = smp->lno;
 954         rp->cno = smp->c_scoff == 255 ? 0 : smp->c_sboff;
 955         return (0);
 956 }
 957
 958 /*
 959  * vs_sm_erase --
 960  *      Erase the small screen area for the scrolling functions.
 961  */
 962 static int
 963 vs_sm_erase(SCR *sp)
 964 {
 965         GS *gp;
 966
 967         gp = sp->gp;
 968         (void)gp->scr_move(sp, LASTLINE(sp), 0);
 969         (void)gp->scr_clrtoeol(sp);
 970         for (; sp->t_rows > sp->t_minrows; --sp->t_rows, --TMAP) {
 971                 (void)gp->scr_move(sp, TMAP - HMAP, 0);
 972                 (void)gp->scr_clrtoeol(sp);
 973         }
 974         return (0);
 975 }
 976
 977 /*
 978  * vs_sm_1down --
 979  *      Scroll the SMAP down one.
 980  *
 981  * PUBLIC: int vs_sm_1down __P((SCR *));
 982  */
 983 int
 984 vs_sm_1down(SCR *sp)
 985 {
 986         /*
 987          * Insert a line at the top of the screen.  Shift the screen map
 988          * down and display a new line at the top of the screen.
 989          */
 990         (void)sp->gp->scr_move(sp, 0, 0);
 991         if (vs_insertln(sp, 1))
 992                 return (1);
 993
 994         /* One-line screens can fail. */
 995         if (IS_ONELINE(sp)) {
 996                 if (vs_sm_prev(sp, HMAP, HMAP))
 997                         return (1);
 998         } else {
 999                 memmove(HMAP + 1, HMAP, (sp->rows - 1) * sizeof(SMAP));
1000                 if (vs_sm_prev(sp, HMAP + 1, HMAP))
1001                         return (1);
1002         }
1003         /* vs_sm_prev() flushed the cache. */
1004         return (vs_line(sp, HMAP, NULL, NULL));
1005 }
1006
1007 /*
1008  * vs_insertln --
1009  *      Insert a line a la curses, make sure to put the information
1010  *      line and other screens back.
1011  */
1012 static int
1013 vs_insertln(SCR *sp, int cnt)
1014 {
1015         GS *gp;
1016         size_t oldy, oldx;
1017
1018         gp = sp->gp;
1019
1020         /* If the screen is vertically split, we can't scroll it. */
1021         if (IS_VSPLIT(sp)) {
1022                 F_SET(sp, SC_SCR_REDRAW);
1023                 return (0);
1024         }
1025
1026         if (IS_ONELINE(sp)) {
1027                 (void)gp->scr_move(sp, LASTLINE(sp), 0);
1028                 (void)gp->scr_clrtoeol(sp);
1029         } else {
1030                 (void)gp->scr_cursor(sp, &oldy, &oldx);
1031                 while (cnt--) {
1032                         (void)gp->scr_move(sp, LASTLINE(sp) - 1, 0);
1033                         (void)gp->scr_deleteln(sp);
1034                         (void)gp->scr_move(sp, oldy, oldx);
1035                         (void)gp->scr_insertln(sp);
1036                 }
1037         }
1038         return (0);
1039 }
1040
1041 /*
1042  * vs_sm_next --
1043  *      Fill in the next entry in the SMAP.
1044  *
1045  * PUBLIC: int vs_sm_next __P((SCR *, SMAP *, SMAP *));
1046  */
1047 int
1048 vs_sm_next(SCR *sp, SMAP *p, SMAP *t)
1049 {
1050         size_t lcnt;
1051
1052         SMAP_FLUSH(t);
1053         if (O_ISSET(sp, O_LEFTRIGHT)) {
1054                 t->lno = p->lno + 1;
1055                 t->coff = p->coff;
1056         } else {
1057                 lcnt = vs_screens(sp, p->lno, NULL);
1058                 if (lcnt == p->soff) {
1059                         t->lno = p->lno + 1;
1060                         t->soff = 1;
1061                 } else {
1062                         t->lno = p->lno;
1063                         t->soff = p->soff + 1;
1064                 }
1065         }
1066         return (0);
1067 }
1068
1069 /*
1070  * vs_sm_prev --
1071  *      Fill in the previous entry in the SMAP.
1072  *
1073  * PUBLIC: int vs_sm_prev __P((SCR *, SMAP *, SMAP *));
1074  */
1075 int
1076 vs_sm_prev(SCR *sp, SMAP *p, SMAP *t)
1077 {
1078         SMAP_FLUSH(t);
1079         if (O_ISSET(sp, O_LEFTRIGHT)) {
1080                 t->lno = p->lno - 1;
1081                 t->coff = p->coff;
1082         } else {
1083                 if (p->soff != 1) {
1084                         t->lno = p->lno;
1085                         t->soff = p->soff - 1;
1086                 } else {
1087                         t->lno = p->lno - 1;
1088                         t->soff = vs_screens(sp, t->lno, NULL);
1089                 }
1090         }
1091         return (t->lno == 0);
1092 }
1093
1094 /*
1095  * vs_sm_cursor --
1096  *      Return the SMAP entry referenced by the cursor.
1097  *
1098  * PUBLIC: int vs_sm_cursor __P((SCR *, SMAP **));
1099  */
1100 int
1101 vs_sm_cursor(SCR *sp, SMAP **smpp)
1102 {
1103         SMAP *p;
1104
1105         /* See if the cursor is not in the map. */
1106         if (sp->lno < HMAP->lno || sp->lno > TMAP->lno)
1107                 return (1);
1108
1109         /* Find the first occurence of the line. */
1110         for (p = HMAP; p->lno != sp->lno; ++p);
1111
1112         /* Fill in the map information until we find the right line. */
1113         for (; p <= TMAP; ++p) {
1114                 /* Short lines are common and easy to detect. */
1115                 if (p != TMAP && (p + 1)->lno != p->lno) {
1116                         *smpp = p;
1117                         return (0);
1118                 }
1119                 if (!SMAP_CACHE(p) && vs_line(sp, p, NULL, NULL))
1120                         return (1);
1121                 if (p->c_eboff >= sp->cno) {
1122                         *smpp = p;
1123                         return (0);
1124                 }
1125         }
1126
1127         /* It was past the end of the map after all. */
1128         return (1);
1129 }
1130
1131 /*
1132  * vs_sm_position --
1133  *      Return the line/column of the top, middle or last line on the screen.
1134  *      (The vi H, M and L commands.)  Here because only the screen routines
1135  *      know what's really out there.
1136  *
1137  * PUBLIC: int vs_sm_position __P((SCR *, MARK *, u_long, pos_t));
1138  */
1139 int
1140 vs_sm_position(SCR *sp, MARK *rp, u_long cnt, pos_t pos)
1141 {
1142         SMAP *smp;
1143         db_recno_t last;
1144
1145         switch (pos) {
1146         case P_TOP:
1147                 /*
1148                  * !!!
1149                  * Historically, an invalid count to the H command failed.
1150                  * We do nothing special here, just making sure that H in
1151                  * an empty screen works.
1152                  */
1153                 if (cnt > TMAP - HMAP)
1154                         goto sof;
1155                 smp = HMAP + cnt;
1156                 if (cnt && !db_exist(sp, smp->lno)) {
1157 sof:                    msgq(sp, M_BERR, "220|Movement past the end-of-screen");
1158                         return (1);
1159                 }
1160                 break;
1161         case P_MIDDLE:
1162                 /*
1163                  * !!!
1164                  * Historically, a count to the M command was ignored.
1165                  * If the screen isn't filled, find the middle of what's
1166                  * real and move there.
1167                  */
1168                 if (!db_exist(sp, TMAP->lno)) {
1169                         if (db_last(sp, &last))
1170                                 return (1);
1171                         for (smp = TMAP; smp->lno > last && smp > HMAP; --smp);
1172                         if (smp > HMAP)
1173                                 smp -= (smp - HMAP) / 2;
1174                 } else
1175                         smp = (HMAP + (TMAP - HMAP) / 2) + cnt;
1176                 break;
1177         case P_BOTTOM:
1178                 /*
1179                  * !!!
1180                  * Historically, an invalid count to the L command failed.
1181                  * If the screen isn't filled, find the bottom of what's
1182                  * real and try to offset from there.
1183                  */
1184                 if (cnt > TMAP - HMAP)
1185                         goto eof;
1186                 smp = TMAP - cnt;
1187                 if (!db_exist(sp, smp->lno)) {
1188                         if (db_last(sp, &last))
1189                                 return (1);
1190                         for (; smp->lno > last && smp > HMAP; --smp);
1191                         if (cnt > smp - HMAP) {
1192 eof:                            msgq(sp, M_BERR,
1193                             "221|Movement past the beginning-of-screen");
1194                                 return (1);
1195                         }
1196                         smp -= cnt;
1197                 }
1198                 break;
1199         default:
1200                 abort();
1201         }
1202
1203         /* Make sure that the cached information is valid. */
1204         if (!SMAP_CACHE(smp) && vs_line(sp, smp, NULL, NULL))
1205                 return (1);
1206         rp->lno = smp->lno;
1207         rp->cno = smp->c_sboff;
1208
1209         return (0);
1210 }
1211
1212 /*
1213  * vs_sm_nlines --
1214  *      Return the number of screen lines from an SMAP entry to the
1215  *      start of some file line, less than a maximum value.
1216  *
1217  * PUBLIC: db_recno_t vs_sm_nlines __P((SCR *, SMAP *, db_recno_t, size_t));
1218  */
1219 db_recno_t
1220 vs_sm_nlines(SCR *sp, SMAP *from_sp, db_recno_t to_lno, size_t max)
1221 {
1222         db_recno_t lno, lcnt;
1223
1224         if (O_ISSET(sp, O_LEFTRIGHT))
1225                 return (from_sp->lno > to_lno ?
1226                     from_sp->lno - to_lno : to_lno - from_sp->lno);
1227
1228         if (from_sp->lno == to_lno)
1229                 return (from_sp->soff - 1);
1230
1231         if (from_sp->lno > to_lno) {
1232                 lcnt = from_sp->soff - 1;       /* Correct for off-by-one. */
1233                 for (lno = from_sp->lno; --lno >= to_lno && lcnt <= max;)
1234                         lcnt += vs_screens(sp, lno, NULL);
1235         } else {
1236                 lno = from_sp->lno;
1237                 lcnt = (vs_screens(sp, lno, NULL) - from_sp->soff) + 1;
1238                 for (; ++lno < to_lno && lcnt <= max;)
1239                         lcnt += vs_screens(sp, lno, NULL);
1240         }
1241         return (lcnt);
1242 }