ex/ex_subst.c

   1 /*-
   2  * Copyright (c) 1992, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  * Copyright (c) 1992, 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: ex_subst.c,v 10.42 2000/06/27 17:19:06 skimo Exp $ (Berkeley) $Date: 2000/06/27 17:19:06 $";
  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 <ctype.h>
  22 #include <errno.h>
  23 #include <limits.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28
  29 #include "../common/common.h"
  30 #include "../vi/vi.h"
  31
  32 #define SUB_FIRST       0x01            /* The 'r' flag isn't reasonable. */
  33 #define SUB_MUSTSETR    0x02            /* The 'r' flag is required. */
  34
  35 static int re_conv __P((SCR *, char **, size_t *, int *));
  36 static int re_cscope_conv __P((SCR *, char **, size_t *, int *));
  37 static int re_sub __P((SCR *,
  38                 char *, char **, size_t *, size_t *, regmatch_t [10]));
  39 static int re_tag_conv __P((SCR *, char **, size_t *, int *));
  40 static int s __P((SCR *, EXCMD *, char *, regex_t *, u_int));
  41
  42 /*
  43  * ex_s --
  44  *      [line [,line]] s[ubstitute] [[/;]pat[/;]/repl[/;] [cgr] [count] [#lp]]
  45  *
  46  *      Substitute on lines matching a pattern.
  47  *
  48  * PUBLIC: int ex_s __P((SCR *, EXCMD *));
  49  */
  50 int
  51 ex_s(sp, cmdp)
  52         SCR *sp;
  53         EXCMD *cmdp;
  54 {
  55         regex_t *re;
  56         size_t blen, len;
  57         u_int flags;
  58         int delim;
  59         char *bp, *ptrn, *rep, *p, *t;
  60
  61         /*
  62          * Skip leading white space.
  63          *
  64          * !!!
  65          * Historic vi allowed any non-alphanumeric to serve as the
  66          * substitution command delimiter.
  67          *
  68          * !!!
  69          * If the arguments are empty, it's the same as &, i.e. we
  70          * repeat the last substitution.
  71          */
  72         if (cmdp->argc == 0)
  73                 goto subagain;
  74         for (p = cmdp->argv[0]->bp,
  75             len = cmdp->argv[0]->len; len > 0; --len, ++p) {
  76                 if (!isblank(*p))
  77                         break;
  78         }
  79         if (len == 0)
  80 subagain:       return (ex_subagain(sp, cmdp));
  81
  82         delim = *p++;
  83         if (isalnum(delim) || delim == '\\')
  84                 return (s(sp, cmdp, p, &sp->subre_c, SUB_MUSTSETR));
  85
  86         /*
  87          * !!!
  88          * The full-blown substitute command reset the remembered
  89          * state of the 'c' and 'g' suffices.
  90          */
  91         sp->c_suffix = sp->g_suffix = 0;
  92
  93         /*
  94          * Get the pattern string, toss escaping characters.
  95          *
  96          * !!!
  97          * Historic vi accepted any of the following forms:
  98          *
  99          *      :s/abc/def/             change "abc" to "def"
 100          *      :s/abc/def              change "abc" to "def"
 101          *      :s/abc/                 delete "abc"
 102          *      :s/abc                  delete "abc"
 103          *
 104          * QUOTING NOTE:
 105          *
 106          * Only toss an escaping character if it escapes a delimiter.
 107          * This means that "s/A/\\\\f" replaces "A" with "\\f".  It
 108          * would be nice to be more regular, i.e. for each layer of
 109          * escaping a single escaping character is removed, but that's
 110          * not how the historic vi worked.
 111          */
 112         for (ptrn = t = p;;) {
 113                 if (p[0] == '\0' || p[0] == delim) {
 114                         if (p[0] == delim)
 115                                 ++p;
 116                         /*
 117                          * !!!
 118                          * Nul terminate the pattern string -- it's passed
 119                          * to regcomp which doesn't understand anything else.
 120                          */
 121                         *t = '\0';
 122                         break;
 123                 }
 124                 if (p[0] == '\\')
 125                         if (p[1] == delim)
 126                                 ++p;
 127                         else if (p[1] == '\\')
 128                                 *t++ = *p++;
 129                 *t++ = *p++;
 130         }
 131
 132         /*
 133          * If the pattern string is empty, use the last RE (not just the
 134          * last substitution RE).
 135          */
 136         if (*ptrn == '\0') {
 137                 if (sp->re == NULL) {
 138                         ex_emsg(sp, NULL, EXM_NOPREVRE);
 139                         return (1);
 140                 }
 141
 142                 /* Re-compile the RE if necessary. */
 143                 if (!F_ISSET(sp, SC_RE_SEARCH) &&
 144                     re_compile(sp, sp->re, sp->re_len,
 145                     NULL, NULL, &sp->re_c, SEARCH_CSEARCH | SEARCH_MSG))
 146                         return (1);
 147                 flags = 0;
 148         } else {
 149                 /*
 150                  * !!!
 151                  * Compile the RE.  Historic practice is that substitutes set
 152                  * the search direction as well as both substitute and search
 153                  * RE's.  We compile the RE twice, as we don't want to bother
 154                  * ref counting the pattern string and (opaque) structure.
 155                  */
 156                 if (re_compile(sp, ptrn, t - ptrn, &sp->re,
 157                     &sp->re_len, &sp->re_c, SEARCH_CSEARCH | SEARCH_MSG))
 158                         return (1);
 159                 if (re_compile(sp, ptrn, t - ptrn, &sp->subre,
 160                     &sp->subre_len, &sp->subre_c, SEARCH_CSUBST | SEARCH_MSG))
 161                         return (1);
 162
 163                 flags = SUB_FIRST;
 164                 sp->searchdir = FORWARD;
 165         }
 166         re = &sp->re_c;
 167
 168         /*
 169          * Get the replacement string.
 170          *
 171          * The special character & (\& if O_MAGIC not set) matches the
 172          * entire RE.  No handling of & is required here, it's done by
 173          * re_sub().
 174          *
 175          * The special character ~ (\~ if O_MAGIC not set) inserts the
 176          * previous replacement string into this replacement string.
 177          * Count ~'s to figure out how much space we need.  We could
 178          * special case nonexistent last patterns or whether or not
 179          * O_MAGIC is set, but it's probably not worth the effort.
 180          *
 181          * QUOTING NOTE:
 182          *
 183          * Only toss an escaping character if it escapes a delimiter or
 184          * if O_MAGIC is set and it escapes a tilde.
 185          *
 186          * !!!
 187          * If the entire replacement pattern is "%", then use the last
 188          * replacement pattern.  This semantic was added to vi in System
 189          * V and then percolated elsewhere, presumably around the time
 190          * that it was added to their version of ed(1).
 191          */
 192         if (p[0] == '\0' || p[0] == delim) {
 193                 if (p[0] == delim)
 194                         ++p;
 195                 if (sp->repl != NULL)
 196                         free(sp->repl);
 197                 sp->repl = NULL;
 198                 sp->repl_len = 0;
 199         } else if (p[0] == '%' && (p[1] == '\0' || p[1] == delim))
 200                 p += p[1] == delim ? 2 : 1;
 201         else {
 202                 for (rep = p, len = 0;
 203                     p[0] != '\0' && p[0] != delim; ++p, ++len)
 204                         if (p[0] == '~')
 205                                 len += sp->repl_len;
 206                 GET_SPACE_RET(sp, bp, blen, len);
 207                 for (t = bp, len = 0, p = rep;;) {
 208                         if (p[0] == '\0' || p[0] == delim) {
 209                                 if (p[0] == delim)
 210                                         ++p;
 211                                 break;
 212                         }
 213                         if (p[0] == '\\') {
 214                                 if (p[1] == delim)
 215                                         ++p;
 216                                 else if (p[1] == '\\') {
 217                                         *t++ = *p++;
 218                                         ++len;
 219                                 } else if (p[1] == '~') {
 220                                         ++p;
 221                                         if (!O_ISSET(sp, O_MAGIC))
 222                                                 goto tilde;
 223                                 }
 224                         } else if (p[0] == '~' && O_ISSET(sp, O_MAGIC)) {
 225 tilde:                          ++p;
 226                                 memcpy(t, sp->repl, sp->repl_len);
 227                                 t += sp->repl_len;
 228                                 len += sp->repl_len;
 229                                 continue;
 230                         }
 231                         *t++ = *p++;
 232                         ++len;
 233                 }
 234                 if ((sp->repl_len = len) != 0) {
 235                         if (sp->repl != NULL)
 236                                 free(sp->repl);
 237                         if ((sp->repl = malloc(len)) == NULL) {
 238                                 msgq(sp, M_SYSERR, NULL);
 239                                 FREE_SPACE(sp, bp, blen);
 240                                 return (1);
 241                         }
 242                         memcpy(sp->repl, bp, len);
 243                 }
 244                 FREE_SPACE(sp, bp, blen);
 245         }
 246         return (s(sp, cmdp, p, re, flags));
 247 }
 248
 249 /*
 250  * ex_subagain --
 251  *      [line [,line]] & [cgr] [count] [#lp]]
 252  *
 253  *      Substitute using the last substitute RE and replacement pattern.
 254  *
 255  * PUBLIC: int ex_subagain __P((SCR *, EXCMD *));
 256  */
 257 int
 258 ex_subagain(sp, cmdp)
 259         SCR *sp;
 260         EXCMD *cmdp;
 261 {
 262         if (sp->subre == NULL) {
 263                 ex_emsg(sp, NULL, EXM_NOPREVRE);
 264                 return (1);
 265         }
 266         if (!F_ISSET(sp, SC_RE_SUBST) &&
 267             re_compile(sp, sp->subre, sp->subre_len,
 268             NULL, NULL, &sp->subre_c, SEARCH_CSUBST | SEARCH_MSG))
 269                 return (1);
 270         return (s(sp,
 271             cmdp, cmdp->argc ? cmdp->argv[0]->bp : NULL, &sp->subre_c, 0));
 272 }
 273
 274 /*
 275  * ex_subtilde --
 276  *      [line [,line]] ~ [cgr] [count] [#lp]]
 277  *
 278  *      Substitute using the last RE and last substitute replacement pattern.
 279  *
 280  * PUBLIC: int ex_subtilde __P((SCR *, EXCMD *));
 281  */
 282 int
 283 ex_subtilde(sp, cmdp)
 284         SCR *sp;
 285         EXCMD *cmdp;
 286 {
 287         if (sp->re == NULL) {
 288                 ex_emsg(sp, NULL, EXM_NOPREVRE);
 289                 return (1);
 290         }
 291         if (!F_ISSET(sp, SC_RE_SEARCH) && re_compile(sp, sp->re,
 292             sp->re_len, NULL, NULL, &sp->re_c, SEARCH_CSEARCH | SEARCH_MSG))
 293                 return (1);
 294         return (s(sp,
 295             cmdp, cmdp->argc ? cmdp->argv[0]->bp : NULL, &sp->re_c, 0));
 296 }
 297
 298 /*
 299  * s --
 300  * Do the substitution.  This stuff is *really* tricky.  There are lots of
 301  * special cases, and general nastiness.  Don't mess with it unless you're
 302  * pretty confident.
 303  *
 304  * The nasty part of the substitution is what happens when the replacement
 305  * string contains newlines.  It's a bit tricky -- consider the information
 306  * that has to be retained for "s/f\(o\)o/^M\1^M\1/".  The solution here is
 307  * to build a set of newline offsets which we use to break the line up later,
 308  * when the replacement is done.  Don't change it unless you're *damned*
 309  * confident.
 310  */
 311 #define NEEDNEWLINE(sp) {                                               \
 312         if (sp->newl_len == sp->newl_cnt) {                             \
 313                 sp->newl_len += 25;                                     \
 314                 REALLOC(sp, sp->newl, size_t *,                         \
 315                     sp->newl_len * sizeof(size_t));                     \
 316                 if (sp->newl == NULL) {                                 \
 317                         sp->newl_len = 0;                               \
 318                         return (1);                                     \
 319                 }                                                       \
 320         }                                                               \
 321 }
 322
 323 #define BUILD(sp, l, len) {                                             \
 324         if (lbclen + (len) > lblen) {                                   \
 325                 lblen += MAX(lbclen + (len), 256);                      \
 326                 REALLOC(sp, lb, char *, lblen);                         \
 327                 if (lb == NULL) {                                       \
 328                         lbclen = 0;                                     \
 329                         return (1);                                     \
 330                 }                                                       \
 331         }                                                               \
 332         memcpy(lb + lbclen, l, len);                                    \
 333         lbclen += len;                                                  \
 334 }
 335
 336 #define NEEDSP(sp, len, pnt) {                                          \
 337         if (lbclen + (len) > lblen) {                                   \
 338                 lblen += MAX(lbclen + (len), 256);                      \
 339                 REALLOC(sp, lb, char *, lblen);                         \
 340                 if (lb == NULL) {                                       \
 341                         lbclen = 0;                                     \
 342                         return (1);                                     \
 343                 }                                                       \
 344                 pnt = lb + lbclen;                                      \
 345         }                                                               \
 346 }
 347
 348 static int
 349 s(sp, cmdp, s, re, flags)
 350         SCR *sp;
 351         EXCMD *cmdp;
 352         char *s;
 353         regex_t *re;
 354         u_int flags;
 355 {
 356         EVENT ev;
 357         MARK from, to;
 358         TEXTH tiq;
 359         db_recno_t elno, lno, slno;
 360         regmatch_t match[10];
 361         size_t blen, cnt, last, lbclen, lblen, len, llen;
 362         size_t offset, saved_offset, scno;
 363         int cflag, lflag, nflag, pflag, rflag;
 364         int didsub, do_eol_match, eflags, empty_ok, eval;
 365         int linechanged, matched, quit, rval;
 366         char *bp, *lb;
 367         CHAR_T *p;
 368
 369         NEEDFILE(sp, cmdp);
 370
 371         slno = sp->lno;
 372         scno = sp->cno;
 373
 374         /*
 375          * !!!
 376          * Historically, the 'g' and 'c' suffices were always toggled as flags,
 377          * so ":s/A/B/" was the same as ":s/A/B/ccgg".  If O_EDCOMPATIBLE was
 378          * not set, they were initialized to 0 for all substitute commands.  If
 379          * O_EDCOMPATIBLE was set, they were initialized to 0 only if the user
 380          * specified substitute/replacement patterns (see ex_s()).
 381          */
 382         if (!O_ISSET(sp, O_EDCOMPATIBLE))
 383                 sp->c_suffix = sp->g_suffix = 0;
 384
 385         /*
 386          * Historic vi permitted the '#', 'l' and 'p' options in vi mode, but
 387          * it only displayed the last change.  I'd disallow them, but they are
 388          * useful in combination with the [v]global commands.  In the current
 389          * model the problem is combining them with the 'c' flag -- the screen
 390          * would have to flip back and forth between the confirm screen and the
 391          * ex print screen, which would be pretty awful.  We do display all
 392          * changes, though, for what that's worth.
 393          *
 394          * !!!
 395          * Historic vi was fairly strict about the order of "options", the
 396          * count, and "flags".  I'm somewhat fuzzy on the difference between
 397          * options and flags, anyway, so this is a simpler approach, and we
 398          * just take it them in whatever order the user gives them.  (The ex
 399          * usage statement doesn't reflect this.)
 400          */
 401         cflag = lflag = nflag = pflag = rflag = 0;
 402         if (s == NULL)
 403                 goto noargs;
 404         for (lno = OOBLNO; *s != '\0'; ++s)
 405                 switch (*s) {
 406                 case ' ':
 407                 case '\t':
 408                         continue;
 409                 case '+':
 410                         ++cmdp->flagoff;
 411                         break;
 412                 case '-':
 413                         --cmdp->flagoff;
 414                         break;
 415                 case '0': case '1': case '2': case '3': case '4':
 416                 case '5': case '6': case '7': case '8': case '9':
 417                         if (lno != OOBLNO)
 418                                 goto usage;
 419                         errno = 0;
 420                         lno = strtoul(s, &s, 10);
 421                         if (*s == '\0')         /* Loop increment correction. */
 422                                 --s;
 423                         if (errno == ERANGE) {
 424                                 if (lno == LONG_MAX)
 425                                         msgq(sp, M_ERR, "153|Count overflow");
 426                                 else if (lno == LONG_MIN)
 427                                         msgq(sp, M_ERR, "154|Count underflow");
 428                                 else
 429                                         msgq(sp, M_SYSERR, NULL);
 430                                 return (1);
 431                         }
 432                         /*
 433                          * In historic vi, the count was inclusive from the
 434                          * second address.
 435                          */
 436                         cmdp->addr1.lno = cmdp->addr2.lno;
 437                         cmdp->addr2.lno += lno - 1;
 438                         if (!db_exist(sp, cmdp->addr2.lno) &&
 439                             db_last(sp, &cmdp->addr2.lno))
 440                                 return (1);
 441                         break;
 442                 case '#':
 443                         nflag = 1;
 444                         break;
 445                 case 'c':
 446                         sp->c_suffix = !sp->c_suffix;
 447
 448                         /* Ex text structure initialization. */
 449                         if (F_ISSET(sp, SC_EX)) {
 450                                 memset(&tiq, 0, sizeof(TEXTH));
 451                                 CIRCLEQ_INIT(&tiq);
 452                         }
 453                         break;
 454                 case 'g':
 455                         sp->g_suffix = !sp->g_suffix;
 456                         break;
 457                 case 'l':
 458                         lflag = 1;
 459                         break;
 460                 case 'p':
 461                         pflag = 1;
 462                         break;
 463                 case 'r':
 464                         if (LF_ISSET(SUB_FIRST)) {
 465                                 msgq(sp, M_ERR,
 466                     "155|Regular expression specified; r flag meaningless");
 467                                 return (1);
 468                         }
 469                         if (!F_ISSET(sp, SC_RE_SEARCH)) {
 470                                 ex_emsg(sp, NULL, EXM_NOPREVRE);
 471                                 return (1);
 472                         }
 473                         rflag = 1;
 474                         re = &sp->re_c;
 475                         break;
 476                 default:
 477                         goto usage;
 478                 }
 479
 480         if (*s != '\0' || !rflag && LF_ISSET(SUB_MUSTSETR)) {
 481 usage:          ex_emsg(sp, cmdp->cmd->usage, EXM_USAGE);
 482                 return (1);
 483         }
 484
 485 noargs: if (F_ISSET(sp, SC_VI) && sp->c_suffix && (lflag || nflag || pflag)) {
 486                 msgq(sp, M_ERR,
 487 "156|The #, l and p flags may not be combined with the c flag in vi mode");
 488                 return (1);
 489         }
 490
 491         /*
 492          * bp:          if interactive, line cache
 493          * blen:        if interactive, line cache length
 494          * lb:          build buffer pointer.
 495          * lbclen:      current length of built buffer.
 496          * lblen;       length of build buffer.
 497          */
 498         bp = lb = NULL;
 499         blen = lbclen = lblen = 0;
 500
 501         /* For each line... */
 502         lno = cmdp->addr1.lno == 0 ? 1 : cmdp->addr1.lno;
 503         for (matched = quit = 0,
 504             elno = cmdp->addr2.lno; !quit && lno <= elno; ++lno) {
 505
 506                 /* Someone's unhappy, time to stop. */
 507                 if (INTERRUPTED(sp))
 508                         break;
 509
 510                 /* Get the line. */
 511                 if (db_get(sp, lno, DBG_FATAL, &s, &llen))
 512                         goto err;
 513
 514                 /*
 515                  * Make a local copy if doing confirmation -- when calling
 516                  * the confirm routine we're likely to lose the cached copy.
 517                  */
 518                 if (sp->c_suffix) {
 519                         if (bp == NULL) {
 520                                 GET_SPACE_RET(sp, bp, blen, llen);
 521                         } else
 522                                 ADD_SPACE_RET(sp, bp, blen, llen);
 523                         memcpy(bp, s, llen);
 524                         s = bp;
 525                 }
 526
 527                 /* Start searching from the beginning. */
 528                 offset = 0;
 529                 len = llen;
 530
 531                 /* Reset the build buffer offset. */
 532                 lbclen = 0;
 533
 534                 /* Reset empty match flag. */
 535                 empty_ok = 1;
 536
 537                 /*
 538                  * We don't want to have to do a setline if the line didn't
 539                  * change -- keep track of whether or not this line changed.
 540                  * If doing confirmations, don't want to keep setting the
 541                  * line if change is refused -- keep track of substitutions.
 542                  */
 543                 didsub = linechanged = 0;
 544
 545                 /* New line, do an EOL match. */
 546                 do_eol_match = 1;
 547
 548                 /* It's not nul terminated, but we pretend it is. */
 549                 eflags = REG_STARTEND;
 550
 551                 /*
 552                  * The search area is from s + offset to the EOL.
 553                  *
 554                  * Generally, match[0].rm_so is the offset of the start
 555                  * of the match from the start of the search, and offset
 556                  * is the offset of the start of the last search.
 557                  */
 558 nextmatch:      match[0].rm_so = 0;
 559                 match[0].rm_eo = len;
 560
 561                 /* Get the next match. */
 562                 eval = regexec(re, (char *)s + offset, 10, match, eflags);
 563
 564                 /*
 565                  * There wasn't a match or if there was an error, deal with
 566                  * it.  If there was a previous match in this line, resolve
 567                  * the changes into the database.  Otherwise, just move on.
 568                  */
 569                 if (eval == REG_NOMATCH)
 570                         goto endmatch;
 571                 if (eval != 0) {
 572                         re_error(sp, eval, re);
 573                         goto err;
 574                 }
 575                 matched = 1;
 576
 577                 /* Only the first search can match an anchored expression. */
 578                 eflags |= REG_NOTBOL;
 579
 580                 /*
 581                  * !!!
 582                  * It's possible to match 0-length strings -- for example, the
 583                  * command s;a*;X;, when matched against the string "aabb" will
 584                  * result in "XbXbX", i.e. the matches are "aa", the space
 585                  * between the b's and the space between the b's and the end of
 586                  * the string.  There is a similar space between the beginning
 587                  * of the string and the a's.  The rule that we use (because vi
 588                  * historically used it) is that any 0-length match, occurring
 589                  * immediately after a match, is ignored.  Otherwise, the above
 590                  * example would have resulted in "XXbXbX".  Another example is
 591                  * incorrectly using " *" to replace groups of spaces with one
 592                  * space.
 593                  *
 594                  * The way we do this is that if we just had a successful match,
 595                  * the starting offset does not skip characters, and the match
 596                  * is empty, ignore the match and move forward.  If there's no
 597                  * more characters in the string, we were attempting to match
 598                  * after the last character, so quit.
 599                  */
 600                 if (!empty_ok && match[0].rm_so == 0 && match[0].rm_eo == 0) {
 601                         empty_ok = 1;
 602                         if (len == 0)
 603                                 goto endmatch;
 604                         BUILD(sp, s + offset, 1)
 605                         ++offset;
 606                         --len;
 607                         goto nextmatch;
 608                 }
 609
 610                 /* Confirm change. */
 611                 if (sp->c_suffix) {
 612                         /*
 613                          * Set the cursor position for confirmation.  Note,
 614                          * if we matched on a '$', the cursor may be past
 615                          * the end of line.
 616                          */
 617                         from.lno = to.lno = lno;
 618                         from.cno = match[0].rm_so + offset;
 619                         to.cno = match[0].rm_eo + offset;
 620                         /*
 621                          * Both ex and vi have to correct for a change before
 622                          * the first character in the line.
 623                          */
 624                         if (llen == 0)
 625                                 from.cno = to.cno = 0;
 626                         if (F_ISSET(sp, SC_VI)) {
 627                                 /*
 628                                  * Only vi has to correct for a change after
 629                                  * the last character in the line.
 630                                  *
 631                                  * XXX
 632                                  * It would be nice to change the vi code so
 633                                  * that we could display a cursor past EOL.
 634                                  */
 635                                 if (to.cno >= llen)
 636                                         to.cno = llen - 1;
 637                                 if (from.cno >= llen)
 638                                         from.cno = llen - 1;
 639
 640                                 sp->lno = from.lno;
 641                                 sp->cno = from.cno;
 642                                 if (vs_refresh(sp, 1))
 643                                         goto err;
 644
 645                                 vs_update(sp, msg_cat(sp,
 646                                     "169|Confirm change? [n]", NULL), NULL);
 647
 648                                 if (v_event_get(sp, &ev, 0, 0))
 649                                         goto err;
 650                                 switch (ev.e_event) {
 651                                 case E_CHARACTER:
 652                                         break;
 653                                 case E_EOF:
 654                                 case E_ERR:
 655                                 case E_INTERRUPT:
 656                                         goto lquit;
 657                                 default:
 658                                         v_event_err(sp, &ev);
 659                                         goto lquit;
 660                                 }
 661                         } else {
 662                                 if (ex_print(sp, cmdp, &from, &to, 0) ||
 663                                     ex_scprint(sp, &from, &to))
 664                                         goto lquit;
 665                                 if (ex_txt(sp, &tiq, 0, TXT_CR))
 666                                         goto err;
 667                                 ev.e_c = tiq.cqh_first->lb[0];
 668                         }
 669
 670                         switch (ev.e_c) {
 671                         case CH_YES:
 672                                 break;
 673                         default:
 674                         case CH_NO:
 675                                 didsub = 0;
 676                                 BUILD(sp, s +offset, match[0].rm_eo);
 677                                 goto skip;
 678                         case CH_QUIT:
 679                                 /* Set the quit/interrupted flags. */
 680 lquit:                          quit = 1;
 681                                 F_SET(sp->gp, G_INTERRUPTED);
 682
 683                                 /*
 684                                  * Resolve any changes, then return to (and
 685                                  * exit from) the main loop.
 686                                  */
 687                                 goto endmatch;
 688                         }
 689                 }
 690
 691                 /*
 692                  * Set the cursor to the last position changed, converting
 693                  * from 1-based to 0-based.
 694                  */
 695                 sp->lno = lno;
 696                 sp->cno = match[0].rm_so;
 697
 698                 /* Copy the bytes before the match into the build buffer. */
 699                 BUILD(sp, s + offset, match[0].rm_so);
 700
 701                 /* Substitute the matching bytes. */
 702                 didsub = 1;
 703                 if (re_sub(sp, s + offset, &lb, &lbclen, &lblen, match))
 704                         goto err;
 705
 706                 /* Set the change flag so we know this line was modified. */
 707                 linechanged = 1;
 708
 709                 /* Move past the matched bytes. */
 710 skip:           offset += match[0].rm_eo;
 711                 len -= match[0].rm_eo;
 712
 713                 /* A match cannot be followed by an empty pattern. */
 714                 empty_ok = 0;
 715
 716                 /*
 717                  * If doing a global change with confirmation, we have to
 718                  * update the screen.  The basic idea is to store the line
 719                  * so the screen update routines can find it, and restart.
 720                  */
 721                 if (didsub && sp->c_suffix && sp->g_suffix) {
 722                         /*
 723                          * The new search offset will be the end of the
 724                          * modified line.
 725                          */
 726                         saved_offset = lbclen;
 727
 728                         /* Copy the rest of the line. */
 729                         if (len)
 730                                 BUILD(sp, s + offset, len)
 731
 732                         /* Set the new offset. */
 733                         offset = saved_offset;
 734
 735                         /* Store inserted lines, adjusting the build buffer. */
 736                         last = 0;
 737                         if (sp->newl_cnt) {
 738                                 for (cnt = 0;
 739                                     cnt < sp->newl_cnt; ++cnt, ++lno, ++elno) {
 740                                         if (db_insert(sp, lno,
 741                                             lb + last, sp->newl[cnt] - last))
 742                                                 goto err;
 743                                         last = sp->newl[cnt] + 1;
 744                                         ++sp->rptlines[L_ADDED];
 745                                 }
 746                                 lbclen -= last;
 747                                 offset -= last;
 748                                 sp->newl_cnt = 0;
 749                         }
 750
 751                         /* Store and retrieve the line. */
 752                         if (db_set(sp, lno, lb + last, lbclen))
 753                                 goto err;
 754                         if (db_get(sp, lno, DBG_FATAL, &s, &llen))
 755                                 goto err;
 756                         ADD_SPACE_RET(sp, bp, blen, llen)
 757                         memcpy(bp, s, llen);
 758                         s = bp;
 759                         len = llen - offset;
 760
 761                         /* Restart the build. */
 762                         lbclen = 0;
 763                         BUILD(sp, s, offset);
 764
 765                         /*
 766                          * If we haven't already done the after-the-string
 767                          * match, do one.  Set REG_NOTEOL so the '$' pattern
 768                          * only matches once.
 769                          */
 770                         if (!do_eol_match)
 771                                 goto endmatch;
 772                         if (offset == len) {
 773                                 do_eol_match = 0;
 774                                 eflags |= REG_NOTEOL;
 775                         }
 776                         goto nextmatch;
 777                 }
 778
 779                 /*
 780                  * If it's a global:
 781                  *
 782                  * If at the end of the string, do a test for the after
 783                  * the string match.  Set REG_NOTEOL so the '$' pattern
 784                  * only matches once.
 785                  */
 786                 if (sp->g_suffix && do_eol_match) {
 787                         if (len == 0) {
 788                                 do_eol_match = 0;
 789                                 eflags |= REG_NOTEOL;
 790                         }
 791                         goto nextmatch;
 792                 }
 793
 794 endmatch:       if (!linechanged)
 795                         continue;
 796
 797                 /* Copy any remaining bytes into the build buffer. */
 798                 if (len)
 799                         BUILD(sp, s + offset, len)
 800
 801                 /* Store inserted lines, adjusting the build buffer. */
 802                 last = 0;
 803                 if (sp->newl_cnt) {
 804                         for (cnt = 0;
 805                             cnt < sp->newl_cnt; ++cnt, ++lno, ++elno) {
 806                                 if (db_insert(sp,
 807                                     lno, lb + last, sp->newl[cnt] - last))
 808                                         goto err;
 809                                 last = sp->newl[cnt] + 1;
 810                                 ++sp->rptlines[L_ADDED];
 811                         }
 812                         lbclen -= last;
 813                         sp->newl_cnt = 0;
 814                 }
 815
 816                 /* Store the changed line. */
 817                 if (db_set(sp, lno, lb + last, lbclen))
 818                         goto err;
 819
 820                 /* Update changed line counter. */
 821                 if (sp->rptlchange != lno) {
 822                         sp->rptlchange = lno;
 823                         ++sp->rptlines[L_CHANGED];
 824                 }
 825
 826                 /*
 827                  * !!!
 828                  * Display as necessary.  Historic practice is to only
 829                  * display the last line of a line split into multiple
 830                  * lines.
 831                  */
 832                 if (lflag || nflag || pflag) {
 833                         from.lno = to.lno = lno;
 834                         from.cno = to.cno = 0;
 835                         if (lflag)
 836                                 (void)ex_print(sp, cmdp, &from, &to, E_C_LIST);
 837                         if (nflag)
 838                                 (void)ex_print(sp, cmdp, &from, &to, E_C_HASH);
 839                         if (pflag)
 840                                 (void)ex_print(sp, cmdp, &from, &to, E_C_PRINT);
 841                 }
 842         }
 843
 844         /*
 845          * !!!
 846          * Historically, vi attempted to leave the cursor at the same place if
 847          * the substitution was done at the current cursor position.  Otherwise
 848          * it moved it to the first non-blank of the last line changed.  There
 849          * were some problems: for example, :s/$/foo/ with the cursor on the
 850          * last character of the line left the cursor on the last character, or
 851          * the & command with multiple occurrences of the matching string in the
 852          * line usually left the cursor in a fairly random position.
 853          *
 854          * We try to do the same thing, with the exception that if the user is
 855          * doing substitution with confirmation, we move to the last line about
 856          * which the user was consulted, as opposed to the last line that they
 857          * actually changed.  This prevents a screen flash if the user doesn't
 858          * change many of the possible lines.
 859          */
 860         if (!sp->c_suffix && (sp->lno != slno || sp->cno != scno)) {
 861                 sp->cno = 0;
 862                 (void)nonblank(sp, sp->lno, &sp->cno);
 863         }
 864
 865         /*
 866          * If not in a global command, and nothing matched, say so.
 867          * Else, if none of the lines displayed, put something up.
 868          */
 869         rval = 0;
 870         if (!matched) {
 871                 if (!F_ISSET(sp, SC_EX_GLOBAL)) {
 872                         msgq(sp, M_ERR, "157|No match found");
 873                         goto err;
 874                 }
 875         } else if (!lflag && !nflag && !pflag)
 876                 F_SET(cmdp, E_AUTOPRINT);
 877
 878         if (0) {
 879 err:            rval = 1;
 880         }
 881
 882         if (bp != NULL)
 883                 FREE_SPACE(sp, bp, blen);
 884         if (lb != NULL)
 885                 free(lb);
 886         return (rval);
 887 }
 888
 889 /*
 890  * re_compile --
 891  *      Compile the RE.
 892  *
 893  * PUBLIC: int re_compile __P((SCR *,
 894  * PUBLIC:     char *, size_t, char **, size_t *, regex_t *, u_int));
 895  */
 896 int
 897 re_compile(sp, ptrn, plen, ptrnp, lenp, rep, flags)
 898         SCR *sp;
 899         char *ptrn, **ptrnp;
 900         size_t plen, *lenp;
 901         regex_t *rep;
 902         u_int flags;
 903 {
 904         size_t len;
 905         int reflags, replaced, rval;
 906         char *p;
 907
 908         /* Set RE flags. */
 909         reflags = 0;
 910         if (LF_ISSET(SEARCH_EXTEND))
 911                 reflags |= REG_EXTENDED;
 912         if (LF_ISSET(SEARCH_IC))
 913                 reflags |= REG_ICASE;
 914         if (LF_ISSET(SEARCH_LITERAL))
 915                 reflags |= REG_NOSPEC;
 916         if (!LF_ISSET(SEARCH_NOOPT | SEARCH_CSCOPE | SEARCH_TAG)) {
 917                 if (O_ISSET(sp, O_EXTENDED))
 918                         reflags |= REG_EXTENDED;
 919                 if (O_ISSET(sp, O_IGNORECASE))
 920                         reflags |= REG_ICASE;
 921                 if (O_ISSET(sp, O_ICLOWER))
 922                         goto iclower;
 923         }
 924         if (LF_ISSET(SEARCH_ICL)) {
 925 iclower:        for (p = ptrn, len = plen; len > 0; ++p, --len)
 926                         if (isupper(*p))
 927                                 break;
 928                 if (len == 0)
 929                         reflags |= REG_ICASE;
 930         }
 931
 932         /* If we're replacing a saved value, clear the old one. */
 933         if (LF_ISSET(SEARCH_CSEARCH) && F_ISSET(sp, SC_RE_SEARCH)) {
 934                 regfree(&sp->re_c);
 935                 F_CLR(sp, SC_RE_SEARCH);
 936         }
 937         if (LF_ISSET(SEARCH_CSUBST) && F_ISSET(sp, SC_RE_SUBST)) {
 938                 regfree(&sp->subre_c);
 939                 F_CLR(sp, SC_RE_SUBST);
 940         }
 941
 942         /*
 943          * If we're saving the string, it's a pattern we haven't seen before,
 944          * so convert the vi-style RE's to POSIX 1003.2 RE's.  Save a copy for
 945          * later recompilation.   Free any previously saved value.
 946          */
 947         if (ptrnp != NULL) {
 948                 replaced = 0;
 949                 if (LF_ISSET(SEARCH_CSCOPE)) {
 950                         if (re_cscope_conv(sp, &ptrn, &plen, &replaced))
 951                                 return (1);
 952                         /*
 953                          * XXX
 954                          * Currently, the match-any-<blank> expression used in
 955                          * re_cscope_conv() requires extended RE's.  This may
 956                          * not be right or safe.
 957                          */
 958                         reflags |= REG_EXTENDED;
 959                 } else if (LF_ISSET(SEARCH_TAG)) {
 960                         if (re_tag_conv(sp, &ptrn, &plen, &replaced))
 961                                 return (1);
 962                 } else if (!LF_ISSET(SEARCH_LITERAL))
 963                         if (re_conv(sp, &ptrn, &plen, &replaced))
 964                                 return (1);
 965
 966                 /* Discard previous pattern. */
 967                 if (*ptrnp != NULL) {
 968                         free(*ptrnp);
 969                         *ptrnp = NULL;
 970                 }
 971                 if (lenp != NULL)
 972                         *lenp = plen;
 973
 974                 /*
 975                  * Copy the string into allocated memory.
 976                  *
 977                  * XXX
 978                  * Regcomp isn't 8-bit clean, so the pattern is nul-terminated
 979                  * for now.  There's just no other solution.
 980                  */
 981                 MALLOC(sp, *ptrnp, char *, plen + 1);
 982                 if (*ptrnp != NULL) {
 983                         memcpy(*ptrnp, ptrn, plen);
 984                         (*ptrnp)[plen] = '\0';
 985                 }
 986
 987                 /* Free up conversion-routine-allocated memory. */
 988                 if (replaced)
 989                         FREE_SPACE(sp, ptrn, 0);
 990
 991                 if (*ptrnp == NULL)
 992                         return (1);
 993
 994                 ptrn = *ptrnp;
 995         }
 996
 997         /*
 998          * XXX
 999          * Regcomp isn't 8-bit clean, so we just lost if the pattern
1000          * contained a nul.  Bummer!
1001          */
1002         if ((rval = regcomp(rep, ptrn, /* plen, */ reflags)) != 0) {
1003                 if (LF_ISSET(SEARCH_MSG))
1004                         re_error(sp, rval, rep);
1005                 return (1);
1006         }
1007
1008         if (LF_ISSET(SEARCH_CSEARCH))
1009                 F_SET(sp, SC_RE_SEARCH);
1010         if (LF_ISSET(SEARCH_CSUBST))
1011                 F_SET(sp, SC_RE_SUBST);
1012
1013         return (0);
1014 }
1015
1016 /*
1017  * re_conv --
1018  *      Convert vi's regular expressions into something that the
1019  *      the POSIX 1003.2 RE functions can handle.
1020  *
1021  * There are three conversions we make to make vi's RE's (specifically
1022  * the global, search, and substitute patterns) work with POSIX RE's.
1023  *
1024  * 1: If O_MAGIC is not set, strip backslashes from the magic character
1025  *    set (.[*~) that have them, and add them to the ones that don't.
1026  * 2: If O_MAGIC is not set, the string "\~" is replaced with the text
1027  *    from the last substitute command's replacement string.  If O_MAGIC
1028  *    is set, it's the string "~".
1029  * 3: The pattern \<ptrn\> does "word" searches, convert it to use the
1030  *    new RE escapes.
1031  *
1032  * !!!/XXX
1033  * This doesn't exactly match the historic behavior of vi because we do
1034  * the ~ substitution before calling the RE engine, so magic characters
1035  * in the replacement string will be expanded by the RE engine, and they
1036  * weren't historically.  It's a bug.
1037  */
1038 static int
1039 re_conv(sp, ptrnp, plenp, replacedp)
1040         SCR *sp;
1041         char **ptrnp;
1042         size_t *plenp;
1043         int *replacedp;
1044 {
1045         size_t blen, len, needlen;
1046         int magic;
1047         char *bp, *p, *t;
1048
1049         /*
1050          * First pass through, we figure out how much space we'll need.
1051          * We do it in two passes, on the grounds that most of the time
1052          * the user is doing a search and won't have magic characters.
1053          * That way we can skip most of the memory allocation and copies.
1054          */
1055         magic = 0;
1056         for (p = *ptrnp, len = *plenp, needlen = 0; len > 0; ++p, --len)
1057                 switch (*p) {
1058                 case '\\':
1059                         if (len > 1) {
1060                                 --len;
1061                                 switch (*++p) {
1062                                 case '<':
1063                                         magic = 1;
1064                                         needlen += sizeof(RE_WSTART);
1065                                         break;
1066                                 case '>':
1067                                         magic = 1;
1068                                         needlen += sizeof(RE_WSTOP);
1069                                         break;
1070                                 case '~':
1071                                         if (!O_ISSET(sp, O_MAGIC)) {
1072                                                 magic = 1;
1073                                                 needlen += sp->repl_len;
1074                                         }
1075                                         break;
1076                                 case '.':
1077                                 case '[':
1078                                 case '*':
1079                                         if (!O_ISSET(sp, O_MAGIC)) {
1080                                                 magic = 1;
1081                                                 needlen += 1;
1082                                         }
1083                                         break;
1084                                 default:
1085                                         needlen += 2;
1086                                 }
1087                         } else
1088                                 needlen += 1;
1089                         break;
1090                 case '~':
1091                         if (O_ISSET(sp, O_MAGIC)) {
1092                                 magic = 1;
1093                                 needlen += sp->repl_len;
1094                         }
1095                         break;
1096                 case '.':
1097                 case '[':
1098                 case '*':
1099                         if (!O_ISSET(sp, O_MAGIC)) {
1100                                 magic = 1;
1101                                 needlen += 2;
1102                         }
1103                         break;
1104                 default:
1105                         needlen += 1;
1106                         break;
1107                 }
1108
1109         if (!magic) {
1110                 *replacedp = 0;
1111                 return (0);
1112         }
1113
1114         /* Get enough memory to hold the final pattern. */
1115         *replacedp = 1;
1116         GET_SPACE_RET(sp, bp, blen, needlen);
1117
1118         for (p = *ptrnp, len = *plenp, t = bp; len > 0; ++p, --len)
1119                 switch (*p) {
1120                 case '\\':
1121                         if (len > 1) {
1122                                 --len;
1123                                 switch (*++p) {
1124                                 case '<':
1125                                         memcpy(t,
1126                                             RE_WSTART, sizeof(RE_WSTART) - 1);
1127                                         t += sizeof(RE_WSTART) - 1;
1128                                         break;
1129                                 case '>':
1130                                         memcpy(t,
1131                                             RE_WSTOP, sizeof(RE_WSTOP) - 1);
1132                                         t += sizeof(RE_WSTOP) - 1;
1133                                         break;
1134                                 case '~':
1135                                         if (O_ISSET(sp, O_MAGIC))
1136                                                 *t++ = '~';
1137                                         else {
1138                                                 memcpy(t,
1139                                                     sp->repl, sp->repl_len);
1140                                                 t += sp->repl_len;
1141                                         }
1142                                         break;
1143                                 case '.':
1144                                 case '[':
1145                                 case '*':
1146                                         if (O_ISSET(sp, O_MAGIC))
1147                                                 *t++ = '\\';
1148                                         *t++ = *p;
1149                                         break;
1150                                 default:
1151                                         *t++ = '\\';
1152                                         *t++ = *p;
1153                                 }
1154                         } else
1155                                 *t++ = '\\';
1156                         break;
1157                 case '~':
1158                         if (O_ISSET(sp, O_MAGIC)) {
1159                                 memcpy(t, sp->repl, sp->repl_len);
1160                                 t += sp->repl_len;
1161                         } else
1162                                 *t++ = '~';
1163                         break;
1164                 case '.':
1165                 case '[':
1166                 case '*':
1167                         if (!O_ISSET(sp, O_MAGIC))
1168                                 *t++ = '\\';
1169                         *t++ = *p;
1170                         break;
1171                 default:
1172                         *t++ = *p;
1173                         break;
1174                 }
1175
1176         *ptrnp = bp;
1177         *plenp = t - bp;
1178         return (0);
1179 }
1180
1181 /*
1182  * re_tag_conv --
1183  *      Convert a tags search path into something that the POSIX
1184  *      1003.2 RE functions can handle.
1185  */
1186 static int
1187 re_tag_conv(sp, ptrnp, plenp, replacedp)
1188         SCR *sp;
1189         char **ptrnp;
1190         size_t *plenp;
1191         int *replacedp;
1192 {
1193         size_t blen, len;
1194         int lastdollar;
1195         char *bp, *p, *t;
1196
1197         len = *plenp;
1198
1199         /* Max memory usage is 2 times the length of the string. */
1200         *replacedp = 1;
1201         GET_SPACE_RET(sp, bp, blen, len * 2);
1202
1203         p = *ptrnp;
1204         t = bp;
1205
1206         /* If the last character is a '/' or '?', we just strip it. */
1207         if (len > 0 && (p[len - 1] == '/' || p[len - 1] == '?'))
1208                 --len;
1209
1210         /* If the next-to-last or last character is a '$', it's magic. */
1211         if (len > 0 && p[len - 1] == '$') {
1212                 --len;
1213                 lastdollar = 1;
1214         } else
1215                 lastdollar = 0;
1216
1217         /* If the first character is a '/' or '?', we just strip it. */
1218         if (len > 0 && (p[0] == '/' || p[0] == '?')) {
1219                 ++p;
1220                 --len;
1221         }
1222
1223         /* If the first or second character is a '^', it's magic. */
1224         if (p[0] == '^') {
1225                 *t++ = *p++;
1226                 --len;
1227         }
1228
1229         /*
1230          * Escape every other magic character we can find, meanwhile stripping
1231          * the backslashes ctags inserts when escaping the search delimiter
1232          * characters.
1233          */
1234         for (; len > 0; --len) {
1235                 if (p[0] == '\\' && (p[1] == '/' || p[1] == '?')) {
1236                         ++p;
1237                         --len;
1238                 } else if (strchr("^.[]$*", p[0]))
1239                         *t++ = '\\';
1240                 *t++ = *p++;
1241         }
1242         if (lastdollar)
1243                 *t++ = '$';
1244
1245         *ptrnp = bp;
1246         *plenp = t - bp;
1247         return (0);
1248 }
1249
1250 /*
1251  * re_cscope_conv --
1252  *       Convert a cscope search path into something that the POSIX
1253  *      1003.2 RE functions can handle.
1254  */
1255 static int
1256 re_cscope_conv(sp, ptrnp, plenp, replacedp)
1257         SCR *sp;
1258         char **ptrnp;
1259         size_t *plenp;
1260         int *replacedp;
1261 {
1262         size_t blen, len, nspaces;
1263         char *bp, *p, *t;
1264
1265         /*
1266          * Each space in the source line printed by cscope represents an
1267          * arbitrary sequence of spaces, tabs, and comments.
1268          */
1269 #define CSCOPE_RE_SPACE         "([ \t]|/\\*([^*]|\\*/)*\\*/)*"
1270         for (nspaces = 0, p = *ptrnp, len = *plenp; len > 0; ++p, --len)
1271                 if (*p == ' ')
1272                         ++nspaces;
1273
1274         /*
1275          * Allocate plenty of space:
1276          *      the string, plus potential escaping characters;
1277          *      nspaces + 2 copies of CSCOPE_RE_SPACE;
1278          *      ^, $, nul terminator characters.
1279          */
1280         *replacedp = 1;
1281         len = (p - *ptrnp) * 2 + (nspaces + 2) * sizeof(CSCOPE_RE_SPACE) + 3;
1282         GET_SPACE_RET(sp, bp, blen, len);
1283
1284         p = *ptrnp;
1285         t = bp;
1286
1287         *t++ = '^';
1288         memcpy(t, CSCOPE_RE_SPACE, sizeof(CSCOPE_RE_SPACE) - 1);
1289         t += sizeof(CSCOPE_RE_SPACE) - 1;
1290
1291         for (len = *plenp; len > 0; ++p, --len)
1292                 if (*p == ' ') {
1293                         memcpy(t, CSCOPE_RE_SPACE, sizeof(CSCOPE_RE_SPACE) - 1);
1294                         t += sizeof(CSCOPE_RE_SPACE) - 1;
1295                 } else {
1296                         if (strchr("\\^.[]$*+?()|{}", *p))
1297                                 *t++ = '\\';
1298                         *t++ = *p;
1299                 }
1300
1301         memcpy(t, CSCOPE_RE_SPACE, sizeof(CSCOPE_RE_SPACE) - 1);
1302         t += sizeof(CSCOPE_RE_SPACE) - 1;
1303         *t++ = '$';
1304
1305         *ptrnp = bp;
1306         *plenp = t - bp;
1307         return (0);
1308 }
1309
1310 /*
1311  * re_error --
1312  *      Report a regular expression error.
1313  *
1314  * PUBLIC: void re_error __P((SCR *, int, regex_t *));
1315  */
1316 void
1317 re_error(sp, errcode, preg)
1318         SCR *sp;
1319         int errcode;
1320         regex_t *preg;
1321 {
1322         size_t s;
1323         char *oe;
1324
1325         s = regerror(errcode, preg, "", 0);
1326         if ((oe = malloc(s)) == NULL)
1327                 msgq(sp, M_SYSERR, NULL);
1328         else {
1329                 (void)regerror(errcode, preg, oe, s);
1330                 msgq(sp, M_ERR, "RE error: %s", oe);
1331                 free(oe);
1332         }
1333 }
1334
1335 /*
1336  * re_sub --
1337  *      Do the substitution for a regular expression.
1338  */
1339 static int
1340 re_sub(sp, ip, lbp, lbclenp, lblenp, match)
1341         SCR *sp;
1342         char *ip;                       /* Input line. */
1343         char **lbp;
1344         size_t *lbclenp, *lblenp;
1345         regmatch_t match[10];
1346 {
1347         enum { C_NOTSET, C_LOWER, C_ONELOWER, C_ONEUPPER, C_UPPER } conv;
1348         size_t lbclen, lblen;           /* Local copies. */
1349         size_t mlen;                    /* Match length. */
1350         size_t rpl;                     /* Remaining replacement length. */
1351         char *rp;                       /* Replacement pointer. */
1352         int ch;
1353         int no;                         /* Match replacement offset. */
1354         char *p, *t;                    /* Buffer pointers. */
1355         char *lb;                       /* Local copies. */
1356
1357         lb = *lbp;                      /* Get local copies. */
1358         lbclen = *lbclenp;
1359         lblen = *lblenp;
1360
1361         /*
1362          * QUOTING NOTE:
1363          *
1364          * There are some special sequences that vi provides in the
1365          * replacement patterns.
1366          *       & string the RE matched (\& if nomagic set)
1367          *      \# n-th regular subexpression
1368          *      \E end \U, \L conversion
1369          *      \e end \U, \L conversion
1370          *      \l convert the next character to lower-case
1371          *      \L convert to lower-case, until \E, \e, or end of replacement
1372          *      \u convert the next character to upper-case
1373          *      \U convert to upper-case, until \E, \e, or end of replacement
1374          *
1375          * Otherwise, since this is the lowest level of replacement, discard
1376          * all escaping characters.  This (hopefully) matches historic practice.
1377          */
1378 #define OUTCH(ch, nltrans) {                                            \
1379         CHAR_T __ch = (ch);                                             \
1380         u_int __value = KEY_VAL(sp, __ch);                              \
1381         if (nltrans && (__value == K_CR || __value == K_NL)) {          \
1382                 NEEDNEWLINE(sp);                                        \
1383                 sp->newl[sp->newl_cnt++] = lbclen;                      \
1384         } else if (conv != C_NOTSET) {                                  \
1385                 switch (conv) {                                         \
1386                 case C_ONELOWER:                                        \
1387                         conv = C_NOTSET;                                \
1388                         /* FALLTHROUGH */                               \
1389                 case C_LOWER:                                           \
1390                         if (isupper(__ch))                              \
1391                                 __ch = tolower(__ch);                   \
1392                         break;                                          \
1393                 case C_ONEUPPER:                                        \
1394                         conv = C_NOTSET;                                \
1395                         /* FALLTHROUGH */                               \
1396                 case C_UPPER:                                           \
1397                         if (islower(__ch))                              \
1398                                 __ch = toupper(__ch);                   \
1399                         break;                                          \
1400                 default:                                                \
1401                         abort();                                        \
1402                 }                                                       \
1403         }                                                               \
1404         NEEDSP(sp, 1, p);                                               \
1405         *p++ = __ch;                                                    \
1406         ++lbclen;                                                       \
1407 }
1408         conv = C_NOTSET;
1409         for (rp = sp->repl, rpl = sp->repl_len, p = lb + lbclen; rpl--;) {
1410                 switch (ch = *rp++) {
1411                 case '&':
1412                         if (O_ISSET(sp, O_MAGIC)) {
1413                                 no = 0;
1414                                 goto subzero;
1415                         }
1416                         break;
1417                 case '\\':
1418                         if (rpl == 0)
1419                                 break;
1420                         --rpl;
1421                         switch (ch = *rp) {
1422                         case '&':
1423                                 ++rp;
1424                                 if (!O_ISSET(sp, O_MAGIC)) {
1425                                         no = 0;
1426                                         goto subzero;
1427                                 }
1428                                 break;
1429                         case '0': case '1': case '2': case '3': case '4':
1430                         case '5': case '6': case '7': case '8': case '9':
1431                                 no = *rp++ - '0';
1432 subzero:                        if (match[no].rm_so == -1 ||
1433                                     match[no].rm_eo == -1)
1434                                         break;
1435                                 mlen = match[no].rm_eo - match[no].rm_so;
1436                                 for (t = ip + match[no].rm_so; mlen--; ++t)
1437                                         OUTCH(*t, 0);
1438                                 continue;
1439                         case 'e':
1440                         case 'E':
1441                                 ++rp;
1442                                 conv = C_NOTSET;
1443                                 continue;
1444                         case 'l':
1445                                 ++rp;
1446                                 conv = C_ONELOWER;
1447                                 continue;
1448                         case 'L':
1449                                 ++rp;
1450                                 conv = C_LOWER;
1451                                 continue;
1452                         case 'u':
1453                                 ++rp;
1454                                 conv = C_ONEUPPER;
1455                                 continue;
1456                         case 'U':
1457                                 ++rp;
1458                                 conv = C_UPPER;
1459                                 continue;
1460                         default:
1461                                 ++rp;
1462                                 break;
1463                         }
1464                 }
1465                 OUTCH(ch, 1);
1466         }
1467
1468         *lbp = lb;                      /* Update caller's information. */
1469         *lbclenp = lbclen;
1470         *lblenp = lblen;
1471         return (0);
1472 }