contrib/nvi2/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 10.53 2011/12/21 20:40:35 zy Exp $";
  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(SCR *, CHAR_T **, size_t *, int *);
  36 static int re_cscope_conv(SCR *, CHAR_T **, size_t *, int *);
  37 static int re_sub(SCR *,
  38                 CHAR_T *, CHAR_T **, size_t *, size_t *, regmatch_t [10]);
  39 static int re_tag_conv(SCR *, CHAR_T **, size_t *, int *);
  40 static int s(SCR *, EXCMD *, CHAR_T *, 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(SCR *, EXCMD *);
  49  */
  50 int
  51 ex_s(SCR *sp, EXCMD *cmdp)
  52 {
  53         regex_t *re;
  54         size_t blen, len;
  55         u_int flags;
  56         int delim;
  57         CHAR_T *bp, *p, *ptrn, *rep, *t;
  58
  59         /*
  60          * Skip leading white space.
  61          *
  62          * !!!
  63          * Historic vi allowed any non-alphanumeric to serve as the
  64          * substitution command delimiter.
  65          *
  66          * !!!
  67          * If the arguments are empty, it's the same as &, i.e. we
  68          * repeat the last substitution.
  69          */
  70         if (cmdp->argc == 0)
  71                 goto subagain;
  72         for (p = cmdp->argv[0]->bp,
  73             len = cmdp->argv[0]->len; len > 0; --len, ++p) {
  74                 if (!cmdskip(*p))
  75                         break;
  76         }
  77         if (len == 0)
  78 subagain:       return (ex_subagain(sp, cmdp));
  79
  80         delim = *p++;
  81         if (!isascii(delim) || isalnum(delim) || delim == '\\')
  82                 return (s(sp, cmdp, p, &sp->subre_c, SUB_MUSTSETR));
  83
  84         /*
  85          * !!!
  86          * The full-blown substitute command reset the remembered
  87          * state of the 'c' and 'g' suffices.
  88          */
  89         sp->c_suffix = sp->g_suffix = 0;
  90
  91         /*
  92          * Get the pattern string, toss escaping characters.
  93          *
  94          * !!!
  95          * Historic vi accepted any of the following forms:
  96          *
  97          *      :s/abc/def/             change "abc" to "def"
  98          *      :s/abc/def              change "abc" to "def"
  99          *      :s/abc/                 delete "abc"
 100          *      :s/abc                  delete "abc"
 101          *
 102          * QUOTING NOTE:
 103          *
 104          * Only toss an escaping character if it escapes a delimiter.
 105          * This means that "s/A/\\\\f" replaces "A" with "\\f".  It
 106          * would be nice to be more regular, i.e. for each layer of
 107          * escaping a single escaping character is removed, but that's
 108          * not how the historic vi worked.
 109          */
 110         for (ptrn = t = p;;) {
 111                 if (p[0] == '\0' || p[0] == delim) {
 112                         if (p[0] == delim)
 113                                 ++p;
 114                         /*
 115                          * !!!
 116                          * Nul terminate the pattern string -- it's passed
 117                          * to regcomp which doesn't understand anything else.
 118                          */
 119                         *t = '\0';
 120                         break;
 121                 }
 122                 if (p[0] == '\\')
 123                         if (p[1] == delim)
 124                                 ++p;
 125                         else if (p[1] == '\\')
 126                                 *t++ = *p++;
 127                 *t++ = *p++;
 128         }
 129
 130         /*
 131          * If the pattern string is empty, use the last RE (not just the
 132          * last substitution RE).
 133          */
 134         if (*ptrn == '\0') {
 135                 if (sp->re == NULL) {
 136                         ex_emsg(sp, NULL, EXM_NOPREVRE);
 137                         return (1);
 138                 }
 139
 140                 /* Re-compile the RE if necessary. */
 141                 if (!F_ISSET(sp, SC_RE_SEARCH) &&
 142                     re_compile(sp, sp->re, sp->re_len,
 143                     NULL, NULL, &sp->re_c, RE_C_SEARCH))
 144                         return (1);
 145                 flags = 0;
 146         } else {
 147                 /*
 148                  * !!!
 149                  * Compile the RE.  Historic practice is that substitutes set
 150                  * the search direction as well as both substitute and search
 151                  * RE's.  We compile the RE twice, as we don't want to bother
 152                  * ref counting the pattern string and (opaque) structure.
 153                  */
 154                 if (re_compile(sp, ptrn, t - ptrn, &sp->re,
 155                     &sp->re_len, &sp->re_c, RE_C_SEARCH))
 156                         return (1);
 157                 if (re_compile(sp, ptrn, t - ptrn, &sp->subre,
 158                     &sp->subre_len, &sp->subre_c, RE_C_SUBST))
 159                         return (1);
 160
 161                 flags = SUB_FIRST;
 162                 sp->searchdir = FORWARD;
 163         }
 164         re = &sp->re_c;
 165
 166         /*
 167          * Get the replacement string.
 168          *
 169          * The special character & (\& if O_MAGIC not set) matches the
 170          * entire RE.  No handling of & is required here, it's done by
 171          * re_sub().
 172          *
 173          * The special character ~ (\~ if O_MAGIC not set) inserts the
 174          * previous replacement string into this replacement string.
 175          * Count ~'s to figure out how much space we need.  We could
 176          * special case nonexistent last patterns or whether or not
 177          * O_MAGIC is set, but it's probably not worth the effort.
 178          *
 179          * QUOTING NOTE:
 180          *
 181          * Only toss an escaping character if it escapes a delimiter or
 182          * if O_MAGIC is set and it escapes a tilde.
 183          *
 184          * !!!
 185          * If the entire replacement pattern is "%", then use the last
 186          * replacement pattern.  This semantic was added to vi in System
 187          * V and then percolated elsewhere, presumably around the time
 188          * that it was added to their version of ed(1).
 189          */
 190         if (p[0] == '\0' || p[0] == delim) {
 191                 if (p[0] == delim)
 192                         ++p;
 193                 if (sp->repl != NULL)
 194                         free(sp->repl);
 195                 sp->repl = NULL;
 196                 sp->repl_len = 0;
 197         } else if (p[0] == '%' && (p[1] == '\0' || p[1] == delim))
 198                 p += p[1] == delim ? 2 : 1;
 199         else {
 200                 for (rep = p, len = 0;
 201                     p[0] != '\0' && p[0] != delim; ++p, ++len)
 202                         if (p[0] == '~')
 203                                 len += sp->repl_len;
 204                 GET_SPACE_RETW(sp, bp, blen, len);
 205                 for (t = bp, len = 0, p = rep;;) {
 206                         if (p[0] == '\0' || p[0] == delim) {
 207                                 if (p[0] == delim)
 208                                         ++p;
 209                                 break;
 210                         }
 211                         if (p[0] == '\\') {
 212                                 if (p[1] == delim)
 213                                         ++p;
 214                                 else if (p[1] == '\\') {
 215                                         *t++ = *p++;
 216                                         ++len;
 217                                 } else if (p[1] == '~') {
 218                                         ++p;
 219                                         if (!O_ISSET(sp, O_MAGIC))
 220                                                 goto tilde;
 221                                 }
 222                         } else if (p[0] == '~' && O_ISSET(sp, O_MAGIC)) {
 223 tilde:                          ++p;
 224                                 MEMCPY(t, sp->repl, sp->repl_len);
 225                                 t += sp->repl_len;
 226                                 len += sp->repl_len;
 227                                 continue;
 228                         }
 229                         *t++ = *p++;
 230                         ++len;
 231                 }
 232                 if ((sp->repl_len = len) != 0) {
 233                         if (sp->repl != NULL)
 234                                 free(sp->repl);
 235                         MALLOC(sp, sp->repl, CHAR_T *, len * sizeof(CHAR_T));
 236                         if (sp->repl == NULL) {
 237                                 FREE_SPACEW(sp, bp, blen);
 238                                 return (1);
 239                         }
 240                         MEMCPY(sp->repl, bp, len);
 241                 }
 242                 FREE_SPACEW(sp, bp, blen);
 243         }
 244         return (s(sp, cmdp, p, re, flags));
 245 }
 246
 247 /*
 248  * ex_subagain --
 249  *      [line [,line]] & [cgr] [count] [#lp]]
 250  *
 251  *      Substitute using the last substitute RE and replacement pattern.
 252  *
 253  * PUBLIC: int ex_subagain(SCR *, EXCMD *);
 254  */
 255 int
 256 ex_subagain(SCR *sp, EXCMD *cmdp)
 257 {
 258         if (sp->subre == NULL) {
 259                 ex_emsg(sp, NULL, EXM_NOPREVRE);
 260                 return (1);
 261         }
 262         if (!F_ISSET(sp, SC_RE_SUBST) &&
 263             re_compile(sp, sp->subre, sp->subre_len,
 264             NULL, NULL, &sp->subre_c, RE_C_SUBST))
 265                 return (1);
 266         return (s(sp,
 267             cmdp, cmdp->argc ? cmdp->argv[0]->bp : NULL, &sp->subre_c, 0));
 268 }
 269
 270 /*
 271  * ex_subtilde --
 272  *      [line [,line]] ~ [cgr] [count] [#lp]]
 273  *
 274  *      Substitute using the last RE and last substitute replacement pattern.
 275  *
 276  * PUBLIC: int ex_subtilde(SCR *, EXCMD *);
 277  */
 278 int
 279 ex_subtilde(SCR *sp, EXCMD *cmdp)
 280 {
 281         if (sp->re == NULL) {
 282                 ex_emsg(sp, NULL, EXM_NOPREVRE);
 283                 return (1);
 284         }
 285         if (!F_ISSET(sp, SC_RE_SEARCH) && re_compile(sp, sp->re,
 286             sp->re_len, NULL, NULL, &sp->re_c, RE_C_SEARCH))
 287                 return (1);
 288         return (s(sp,
 289             cmdp, cmdp->argc ? cmdp->argv[0]->bp : NULL, &sp->re_c, 0));
 290 }
 291
 292 /*
 293  * s --
 294  * Do the substitution.  This stuff is *really* tricky.  There are lots of
 295  * special cases, and general nastiness.  Don't mess with it unless you're
 296  * pretty confident.
 297  *
 298  * The nasty part of the substitution is what happens when the replacement
 299  * string contains newlines.  It's a bit tricky -- consider the information
 300  * that has to be retained for "s/f\(o\)o/^M\1^M\1/".  The solution here is
 301  * to build a set of newline offsets which we use to break the line up later,
 302  * when the replacement is done.  Don't change it unless you're *damned*
 303  * confident.
 304  */
 305 #define NEEDNEWLINE(sp) {                                               \
 306         if (sp->newl_len == sp->newl_cnt) {                             \
 307                 sp->newl_len += 25;                                     \
 308                 REALLOC(sp, sp->newl, size_t *,                         \
 309                     sp->newl_len * sizeof(size_t));                     \
 310                 if (sp->newl == NULL) {                                 \
 311                         sp->newl_len = 0;                               \
 312                         return (1);                                     \
 313                 }                                                       \
 314         }                                                               \
 315 }
 316
 317 #define BUILD(sp, l, len) {                                             \
 318         if (lbclen + (len) > lblen) {                                   \
 319                 lblen = p2roundup(MAX(lbclen + (len), 256));            \
 320                 REALLOC(sp, lb, CHAR_T *, lblen * sizeof(CHAR_T));      \
 321                 if (lb == NULL) {                                       \
 322                         lbclen = 0;                                     \
 323                         return (1);                                     \
 324                 }                                                       \
 325         }                                                               \
 326         MEMCPY(lb + lbclen, l, len);                                    \
 327         lbclen += len;                                                  \
 328 }
 329
 330 #define NEEDSP(sp, len, pnt) {                                          \
 331         if (lbclen + (len) > lblen) {                                   \
 332                 lblen = p2roundup(MAX(lbclen + (len), 256));            \
 333                 REALLOC(sp, lb, CHAR_T *, lblen * sizeof(CHAR_T));      \
 334                 if (lb == NULL) {                                       \
 335                         lbclen = 0;                                     \
 336                         return (1);                                     \
 337                 }                                                       \
 338                 pnt = lb + lbclen;                                      \
 339         }                                                               \
 340 }
 341
 342 static int
 343 s(SCR *sp, EXCMD *cmdp, CHAR_T *s, regex_t *re, u_int flags)
 344 {
 345         EVENT ev;
 346         MARK from, to;
 347         TEXTH tiq[] = {{ 0 }};
 348         recno_t elno, lno, slno;
 349         u_long ul;
 350         regmatch_t match[10];
 351         size_t blen, cnt, last, lbclen, lblen, len, llen;
 352         size_t offset, saved_offset, scno;
 353         int cflag, lflag, nflag, pflag, rflag;
 354         int didsub, do_eol_match, eflags, empty_ok, eval;
 355         int linechanged, matched, quit, rval;
 356         CHAR_T *bp, *lb;
 357         enum nresult nret;
 358
 359         NEEDFILE(sp, cmdp);
 360
 361         slno = sp->lno;
 362         scno = sp->cno;
 363
 364         /*
 365          * !!!
 366          * Historically, the 'g' and 'c' suffices were always toggled as flags,
 367          * so ":s/A/B/" was the same as ":s/A/B/ccgg".  If O_EDCOMPATIBLE was
 368          * not set, they were initialized to 0 for all substitute commands.  If
 369          * O_EDCOMPATIBLE was set, they were initialized to 0 only if the user
 370          * specified substitute/replacement patterns (see ex_s()).
 371          */
 372         if (!O_ISSET(sp, O_EDCOMPATIBLE))
 373                 sp->c_suffix = sp->g_suffix = 0;
 374
 375         /*
 376          * Historic vi permitted the '#', 'l' and 'p' options in vi mode, but
 377          * it only displayed the last change.  I'd disallow them, but they are
 378          * useful in combination with the [v]global commands.  In the current
 379          * model the problem is combining them with the 'c' flag -- the screen
 380          * would have to flip back and forth between the confirm screen and the
 381          * ex print screen, which would be pretty awful.  We do display all
 382          * changes, though, for what that's worth.
 383          *
 384          * !!!
 385          * Historic vi was fairly strict about the order of "options", the
 386          * count, and "flags".  I'm somewhat fuzzy on the difference between
 387          * options and flags, anyway, so this is a simpler approach, and we
 388          * just take it them in whatever order the user gives them.  (The ex
 389          * usage statement doesn't reflect this.)
 390          */
 391         cflag = lflag = nflag = pflag = rflag = 0;
 392         if (s == NULL)
 393                 goto noargs;
 394         for (lno = OOBLNO; *s != '\0'; ++s)
 395                 switch (*s) {
 396                 case ' ':
 397                 case '\t':
 398                         continue;
 399                 case '+':
 400                         ++cmdp->flagoff;
 401                         break;
 402                 case '-':
 403                         --cmdp->flagoff;
 404                         break;
 405                 case '0': case '1': case '2': case '3': case '4':
 406                 case '5': case '6': case '7': case '8': case '9':
 407                         if (lno != OOBLNO)
 408                                 goto usage;
 409                         errno = 0;
 410                         nret = nget_uslong(&ul, s, &s, 10);
 411                         lno = ul;
 412                         if (*s == '\0')         /* Loop increment correction. */
 413                                 --s;
 414                         if (nret != NUM_OK) {
 415                                 if (nret == NUM_OVER)
 416                                         msgq(sp, M_ERR, "153|Count overflow");
 417                                 else if (nret == NUM_UNDER)
 418                                         msgq(sp, M_ERR, "154|Count underflow");
 419                                 else
 420                                         msgq(sp, M_SYSERR, NULL);
 421                                 return (1);
 422                         }
 423                         /*
 424                          * In historic vi, the count was inclusive from the
 425                          * second address.
 426                          */
 427                         cmdp->addr1.lno = cmdp->addr2.lno;
 428                         cmdp->addr2.lno += lno - 1;
 429                         if (!db_exist(sp, cmdp->addr2.lno) &&
 430                             db_last(sp, &cmdp->addr2.lno))
 431                                 return (1);
 432                         break;
 433                 case '#':
 434                         nflag = 1;
 435                         break;
 436                 case 'c':
 437                         sp->c_suffix = !sp->c_suffix;
 438
 439                         /* Ex text structure initialization. */
 440                         if (F_ISSET(sp, SC_EX))
 441                                 TAILQ_INIT(tiq);
 442                         break;
 443                 case 'g':
 444                         sp->g_suffix = !sp->g_suffix;
 445                         break;
 446                 case 'l':
 447                         lflag = 1;
 448                         break;
 449                 case 'p':
 450                         pflag = 1;
 451                         break;
 452                 case 'r':
 453                         if (LF_ISSET(SUB_FIRST)) {
 454                                 msgq(sp, M_ERR,
 455                     "155|Regular expression specified; r flag meaningless");
 456                                 return (1);
 457                         }
 458                         if (!F_ISSET(sp, SC_RE_SEARCH)) {
 459                                 ex_emsg(sp, NULL, EXM_NOPREVRE);
 460                                 return (1);
 461                         }
 462                         rflag = 1;
 463                         re = &sp->re_c;
 464                         break;
 465                 default:
 466                         goto usage;
 467                 }
 468
 469         if (*s != '\0' || (!rflag && LF_ISSET(SUB_MUSTSETR))) {
 470 usage:          ex_emsg(sp, cmdp->cmd->usage, EXM_USAGE);
 471                 return (1);
 472         }
 473
 474 noargs: if (F_ISSET(sp, SC_VI) && sp->c_suffix && (lflag || nflag || pflag)) {
 475                 msgq(sp, M_ERR,
 476 "156|The #, l and p flags may not be combined with the c flag in vi mode");
 477                 return (1);
 478         }
 479
 480         /*
 481          * bp:          if interactive, line cache
 482          * blen:        if interactive, line cache length
 483          * lb:          build buffer pointer.
 484          * lbclen:      current length of built buffer.
 485          * lblen;       length of build buffer.
 486          */
 487         bp = lb = NULL;
 488         blen = lbclen = lblen = 0;
 489
 490         /* For each line... */
 491         lno = cmdp->addr1.lno == 0 ? 1 : cmdp->addr1.lno;
 492         for (matched = quit = 0,
 493             elno = cmdp->addr2.lno; !quit && lno <= elno; ++lno) {
 494
 495                 /* Someone's unhappy, time to stop. */
 496                 if (INTERRUPTED(sp))
 497                         break;
 498
 499                 /* Get the line. */
 500                 if (db_get(sp, lno, DBG_FATAL, &s, &llen))
 501                         goto err;
 502
 503                 /*
 504                  * Make a local copy if doing confirmation -- when calling
 505                  * the confirm routine we're likely to lose the cached copy.
 506                  */
 507                 if (sp->c_suffix) {
 508                         if (bp == NULL) {
 509                                 GET_SPACE_RETW(sp, bp, blen, llen);
 510                         } else
 511                                 ADD_SPACE_RETW(sp, bp, blen, llen);
 512                         MEMCPY(bp, s, llen);
 513                         s = bp;
 514                 }
 515
 516                 /* Start searching from the beginning. */
 517                 offset = 0;
 518                 len = llen;
 519
 520                 /* Reset the build buffer offset. */
 521                 lbclen = 0;
 522
 523                 /* Reset empty match flag. */
 524                 empty_ok = 1;
 525
 526                 /*
 527                  * We don't want to have to do a setline if the line didn't
 528                  * change -- keep track of whether or not this line changed.
 529                  * If doing confirmations, don't want to keep setting the
 530                  * line if change is refused -- keep track of substitutions.
 531                  */
 532                 didsub = linechanged = 0;
 533
 534                 /* New line, do an EOL match. */
 535                 do_eol_match = 1;
 536
 537                 /* It's not nul terminated, but we pretend it is. */
 538                 eflags = REG_STARTEND;
 539
 540                 /*
 541                  * The search area is from s + offset to the EOL.
 542                  *
 543                  * Generally, match[0].rm_so is the offset of the start
 544                  * of the match from the start of the search, and offset
 545                  * is the offset of the start of the last search.
 546                  */
 547 nextmatch:      match[0].rm_so = 0;
 548                 match[0].rm_eo = len;
 549
 550                 /* Get the next match. */
 551                 eval = regexec(re, s + offset, 10, match, eflags);
 552
 553                 /*
 554                  * There wasn't a match or if there was an error, deal with
 555                  * it.  If there was a previous match in this line, resolve
 556                  * the changes into the database.  Otherwise, just move on.
 557                  */
 558                 if (eval == REG_NOMATCH)
 559                         goto endmatch;
 560                 if (eval != 0) {
 561                         re_error(sp, eval, re);
 562                         goto err;
 563                 }
 564                 matched = 1;
 565
 566                 /* Only the first search can match an anchored expression. */
 567                 eflags |= REG_NOTBOL;
 568
 569                 /*
 570                  * !!!
 571                  * It's possible to match 0-length strings -- for example, the
 572                  * command s;a*;X;, when matched against the string "aabb" will
 573                  * result in "XbXbX", i.e. the matches are "aa", the space
 574                  * between the b's and the space between the b's and the end of
 575                  * the string.  There is a similar space between the beginning
 576                  * of the string and the a's.  The rule that we use (because vi
 577                  * historically used it) is that any 0-length match, occurring
 578                  * immediately after a match, is ignored.  Otherwise, the above
 579                  * example would have resulted in "XXbXbX".  Another example is
 580                  * incorrectly using " *" to replace groups of spaces with one
 581                  * space.
 582                  *
 583                  * The way we do this is that if we just had a successful match,
 584                  * the starting offset does not skip characters, and the match
 585                  * is empty, ignore the match and move forward.  If there's no
 586                  * more characters in the string, we were attempting to match
 587                  * after the last character, so quit.
 588                  */
 589                 if (!empty_ok && match[0].rm_so == 0 && match[0].rm_eo == 0) {
 590                         empty_ok = 1;
 591                         if (len == 0)
 592                                 goto endmatch;
 593                         BUILD(sp, s + offset, 1)
 594                         ++offset;
 595                         --len;
 596                         goto nextmatch;
 597                 }
 598
 599                 /* Confirm change. */
 600                 if (sp->c_suffix) {
 601                         /*
 602                          * Set the cursor position for confirmation.  Note,
 603                          * if we matched on a '$', the cursor may be past
 604                          * the end of line.
 605                          */
 606                         from.lno = to.lno = lno;
 607                         from.cno = match[0].rm_so + offset;
 608                         to.cno = match[0].rm_eo + offset;
 609                         /*
 610                          * Both ex and vi have to correct for a change before
 611                          * the first character in the line.
 612                          */
 613                         if (llen == 0)
 614                                 from.cno = to.cno = 0;
 615                         if (F_ISSET(sp, SC_VI)) {
 616                                 /*
 617                                  * Only vi has to correct for a change after
 618                                  * the last character in the line.
 619                                  *
 620                                  * XXX
 621                                  * It would be nice to change the vi code so
 622                                  * that we could display a cursor past EOL.
 623                                  */
 624                                 if (to.cno >= llen)
 625                                         to.cno = llen - 1;
 626                                 if (from.cno >= llen)
 627                                         from.cno = llen - 1;
 628
 629                                 sp->lno = from.lno;
 630                                 sp->cno = from.cno;
 631                                 if (vs_refresh(sp, 1))
 632                                         goto err;
 633
 634                                 vs_update(sp, msg_cat(sp,
 635                                     "169|Confirm change? [n]", NULL), NULL);
 636
 637                                 if (v_event_get(sp, &ev, 0, 0))
 638                                         goto err;
 639                                 switch (ev.e_event) {
 640                                 case E_CHARACTER:
 641                                         break;
 642                                 case E_EOF:
 643                                 case E_ERR:
 644                                 case E_INTERRUPT:
 645                                         goto lquit;
 646                                 default:
 647                                         v_event_err(sp, &ev);
 648                                         goto lquit;
 649                                 }
 650                         } else {
 651                                 if (ex_print(sp, cmdp, &from, &to, 0) ||
 652                                     ex_scprint(sp, &from, &to))
 653                                         goto lquit;
 654                                 if (ex_txt(sp, tiq, 0, TXT_CR))
 655                                         goto err;
 656                                 ev.e_c = TAILQ_FIRST(tiq)->lb[0];
 657                         }
 658
 659                         switch (ev.e_c) {
 660                         case CH_YES:
 661                                 break;
 662                         default:
 663                         case CH_NO:
 664                                 didsub = 0;
 665                                 BUILD(sp, s +offset, match[0].rm_eo);
 666                                 goto skip;
 667                         case CH_QUIT:
 668                                 /* Set the quit/interrupted flags. */
 669 lquit:                          quit = 1;
 670                                 F_SET(sp->gp, G_INTERRUPTED);
 671
 672                                 /*
 673                                  * Resolve any changes, then return to (and
 674                                  * exit from) the main loop.
 675                                  */
 676                                 goto endmatch;
 677                         }
 678                 }
 679
 680                 /*
 681                  * Set the cursor to the last position changed, converting
 682                  * from 1-based to 0-based.
 683                  */
 684                 sp->lno = lno;
 685                 sp->cno = match[0].rm_so;
 686
 687                 /* Copy the bytes before the match into the build buffer. */
 688                 BUILD(sp, s + offset, match[0].rm_so);
 689
 690                 /* Substitute the matching bytes. */
 691                 didsub = 1;
 692                 if (re_sub(sp, s + offset, &lb, &lbclen, &lblen, match))
 693                         goto err;
 694
 695                 /* Set the change flag so we know this line was modified. */
 696                 linechanged = 1;
 697
 698                 /* Move past the matched bytes. */
 699 skip:           offset += match[0].rm_eo;
 700                 len -= match[0].rm_eo;
 701
 702                 /* A match cannot be followed by an empty pattern. */
 703                 empty_ok = 0;
 704
 705                 /*
 706                  * If doing a global change with confirmation, we have to
 707                  * update the screen.  The basic idea is to store the line
 708                  * so the screen update routines can find it, and restart.
 709                  */
 710                 if (didsub && sp->c_suffix && sp->g_suffix) {
 711                         /*
 712                          * The new search offset will be the end of the
 713                          * modified line.
 714                          */
 715                         saved_offset = lbclen;
 716
 717                         /* Copy the rest of the line. */
 718                         if (len)
 719                                 BUILD(sp, s + offset, len)
 720
 721                         /* Set the new offset. */
 722                         offset = saved_offset;
 723
 724                         /* Store inserted lines, adjusting the build buffer. */
 725                         last = 0;
 726                         if (sp->newl_cnt) {
 727                                 for (cnt = 0;
 728                                     cnt < sp->newl_cnt; ++cnt, ++lno, ++elno) {
 729                                         if (db_insert(sp, lno,
 730                                             lb + last, sp->newl[cnt] - last))
 731                                                 goto err;
 732                                         last = sp->newl[cnt] + 1;
 733                                         ++sp->rptlines[L_ADDED];
 734                                 }
 735                                 lbclen -= last;
 736                                 offset -= last;
 737                                 sp->newl_cnt = 0;
 738                         }
 739
 740                         /* Store and retrieve the line. */
 741                         if (db_set(sp, lno, lb + last, lbclen))
 742                                 goto err;
 743                         if (db_get(sp, lno, DBG_FATAL, &s, &llen))
 744                                 goto err;
 745                         ADD_SPACE_RETW(sp, bp, blen, llen)
 746                         MEMCPY(bp, s, llen);
 747                         s = bp;
 748                         len = llen - offset;
 749
 750                         /* Restart the build. */
 751                         lbclen = 0;
 752                         BUILD(sp, s, offset);
 753
 754                         /*
 755                          * If we haven't already done the after-the-string
 756                          * match, do one.  Set REG_NOTEOL so the '$' pattern
 757                          * only matches once.
 758                          */
 759                         if (!do_eol_match)
 760                                 goto endmatch;
 761                         if (offset == len) {
 762                                 do_eol_match = 0;
 763                                 eflags |= REG_NOTEOL;
 764                         }
 765                         goto nextmatch;
 766                 }
 767
 768                 /*
 769                  * If it's a global:
 770                  *
 771                  * If at the end of the string, do a test for the after
 772                  * the string match.  Set REG_NOTEOL so the '$' pattern
 773                  * only matches once.
 774                  */
 775                 if (sp->g_suffix && do_eol_match) {
 776                         if (len == 0) {
 777                                 do_eol_match = 0;
 778                                 eflags |= REG_NOTEOL;
 779                         }
 780                         goto nextmatch;
 781                 }
 782
 783 endmatch:       if (!linechanged)
 784                         continue;
 785
 786                 /* Copy any remaining bytes into the build buffer. */
 787                 if (len)
 788                         BUILD(sp, s + offset, len)
 789
 790                 /* Store inserted lines, adjusting the build buffer. */
 791                 last = 0;
 792                 if (sp->newl_cnt) {
 793                         for (cnt = 0;
 794                             cnt < sp->newl_cnt; ++cnt, ++lno, ++elno) {
 795                                 if (db_insert(sp,
 796                                     lno, lb + last, sp->newl[cnt] - last))
 797                                         goto err;
 798                                 last = sp->newl[cnt] + 1;
 799                                 ++sp->rptlines[L_ADDED];
 800                         }
 801                         lbclen -= last;
 802                         sp->newl_cnt = 0;
 803                 }
 804
 805                 /* Store the changed line. */
 806                 if (db_set(sp, lno, lb + last, lbclen))
 807                         goto err;
 808
 809                 /* Update changed line counter. */
 810                 if (sp->rptlchange != lno) {
 811                         sp->rptlchange = lno;
 812                         ++sp->rptlines[L_CHANGED];
 813                 }
 814
 815                 /*
 816                  * !!!
 817                  * Display as necessary.  Historic practice is to only
 818                  * display the last line of a line split into multiple
 819                  * lines.
 820                  */
 821                 if (lflag || nflag || pflag) {
 822                         from.lno = to.lno = lno;
 823                         from.cno = to.cno = 0;
 824                         if (lflag)
 825                                 (void)ex_print(sp, cmdp, &from, &to, E_C_LIST);
 826                         if (nflag)
 827                                 (void)ex_print(sp, cmdp, &from, &to, E_C_HASH);
 828                         if (pflag)
 829                                 (void)ex_print(sp, cmdp, &from, &to, E_C_PRINT);
 830                 }
 831         }
 832
 833         /*
 834          * !!!
 835          * Historically, vi attempted to leave the cursor at the same place if
 836          * the substitution was done at the current cursor position.  Otherwise
 837          * it moved it to the first non-blank of the last line changed.  There
 838          * were some problems: for example, :s/$/foo/ with the cursor on the
 839          * last character of the line left the cursor on the last character, or
 840          * the & command with multiple occurrences of the matching string in the
 841          * line usually left the cursor in a fairly random position.
 842          *
 843          * We try to do the same thing, with the exception that if the user is
 844          * doing substitution with confirmation, we move to the last line about
 845          * which the user was consulted, as opposed to the last line that they
 846          * actually changed.  This prevents a screen flash if the user doesn't
 847          * change many of the possible lines.
 848          */
 849         if (!sp->c_suffix && (sp->lno != slno || sp->cno != scno)) {
 850                 sp->cno = 0;
 851                 (void)nonblank(sp, sp->lno, &sp->cno);
 852         }
 853
 854         /*
 855          * If not in a global command, and nothing matched, say so.
 856          * Else, if none of the lines displayed, put something up.
 857          */
 858         rval = 0;
 859         if (!matched) {
 860                 if (!F_ISSET(sp, SC_EX_GLOBAL)) {
 861                         msgq(sp, M_ERR, "157|No match found");
 862                         goto err;
 863                 }
 864         } else if (!lflag && !nflag && !pflag)
 865                 F_SET(cmdp, E_AUTOPRINT);
 866
 867         if (0) {
 868 err:            rval = 1;
 869         }
 870
 871         if (bp != NULL)
 872                 FREE_SPACEW(sp, bp, blen);
 873         if (lb != NULL)
 874                 free(lb);
 875         return (rval);
 876 }
 877
 878 /*
 879  * re_compile --
 880  *      Compile the RE.
 881  *
 882  * PUBLIC: int re_compile(SCR *,
 883  * PUBLIC:     CHAR_T *, size_t, CHAR_T **, size_t *, regex_t *, u_int);
 884  */
 885 int
 886 re_compile(SCR *sp, CHAR_T *ptrn, size_t plen, CHAR_T **ptrnp, size_t *lenp, regex_t *rep, u_int flags)
 887 {
 888         size_t len;
 889         int reflags, replaced, rval;
 890         CHAR_T *p;
 891
 892         /* Set RE flags. */
 893         reflags = 0;
 894         if (!LF_ISSET(RE_C_CSCOPE | RE_C_TAG)) {
 895                 if (O_ISSET(sp, O_EXTENDED))
 896                         reflags |= REG_EXTENDED;
 897                 if (O_ISSET(sp, O_IGNORECASE))
 898                         reflags |= REG_ICASE;
 899                 if (O_ISSET(sp, O_ICLOWER)) {
 900                         for (p = ptrn, len = plen; len > 0; ++p, --len)
 901                                 if (ISUPPER(*p))
 902                                         break;
 903                         if (len == 0)
 904                                 reflags |= REG_ICASE;
 905                 }
 906         }
 907
 908         /* If we're replacing a saved value, clear the old one. */
 909         if (LF_ISSET(RE_C_SEARCH) && F_ISSET(sp, SC_RE_SEARCH)) {
 910                 regfree(&sp->re_c);
 911                 F_CLR(sp, SC_RE_SEARCH);
 912         }
 913         if (LF_ISSET(RE_C_SUBST) && F_ISSET(sp, SC_RE_SUBST)) {
 914                 regfree(&sp->subre_c);
 915                 F_CLR(sp, SC_RE_SUBST);
 916         }
 917
 918         /*
 919          * If we're saving the string, it's a pattern we haven't seen before,
 920          * so convert the vi-style RE's to POSIX 1003.2 RE's.  Save a copy for
 921          * later recompilation.   Free any previously saved value.
 922          */
 923         if (ptrnp != NULL) {
 924                 replaced = 0;
 925                 if (LF_ISSET(RE_C_CSCOPE)) {
 926                         if (re_cscope_conv(sp, &ptrn, &plen, &replaced))
 927                                 return (1);
 928                         /*
 929                          * XXX
 930                          * Currently, the match-any-<blank> expression used in
 931                          * re_cscope_conv() requires extended RE's.  This may
 932                          * not be right or safe.
 933                          */
 934                         reflags |= REG_EXTENDED;
 935                 } else if (LF_ISSET(RE_C_TAG)) {
 936                         if (re_tag_conv(sp, &ptrn, &plen, &replaced))
 937                                 return (1);
 938                 } else
 939                         if (re_conv(sp, &ptrn, &plen, &replaced))
 940                                 return (1);
 941
 942                 /* Discard previous pattern. */
 943                 if (*ptrnp != NULL) {
 944                         free(*ptrnp);
 945                         *ptrnp = NULL;
 946                 }
 947                 if (lenp != NULL)
 948                         *lenp = plen;
 949
 950                 /*
 951                  * Copy the string into allocated memory.
 952                  *
 953                  * XXX
 954                  * Regcomp isn't 8-bit clean, so the pattern is nul-terminated
 955                  * for now.  There's just no other solution.
 956                  */
 957                 MALLOC(sp, *ptrnp, CHAR_T *, (plen + 1) * sizeof(CHAR_T));
 958                 if (*ptrnp != NULL) {
 959                         MEMCPY(*ptrnp, ptrn, plen);
 960                         (*ptrnp)[plen] = '\0';
 961                 }
 962
 963                 /* Free up conversion-routine-allocated memory. */
 964                 if (replaced)
 965                         FREE_SPACEW(sp, ptrn, 0);
 966
 967                 if (*ptrnp == NULL)
 968                         return (1);
 969
 970                 ptrn = *ptrnp;
 971         }
 972
 973         /*
 974          * XXX
 975          * Regcomp isn't 8-bit clean, so we just lost if the pattern
 976          * contained a nul.  Bummer!
 977          */
 978         if ((rval = regcomp(rep, ptrn, /* plen, */ reflags)) != 0) {
 979                 if (!LF_ISSET(RE_C_SILENT))
 980                         re_error(sp, rval, rep);
 981                 return (1);
 982         }
 983
 984         if (LF_ISSET(RE_C_SEARCH))
 985                 F_SET(sp, SC_RE_SEARCH);
 986         if (LF_ISSET(RE_C_SUBST))
 987                 F_SET(sp, SC_RE_SUBST);
 988
 989         return (0);
 990 }
 991
 992 /*
 993  * re_conv --
 994  *      Convert vi's regular expressions into something that the
 995  *      the POSIX 1003.2 RE functions can handle.
 996  *
 997  * There are three conversions we make to make vi's RE's (specifically
 998  * the global, search, and substitute patterns) work with POSIX RE's.
 999  *
1000  * 1: If O_MAGIC is not set, strip backslashes from the magic character
1001  *    set (.[*~) that have them, and add them to the ones that don't.
1002  * 2: If O_MAGIC is not set, the string "\~" is replaced with the text
1003  *    from the last substitute command's replacement string.  If O_MAGIC
1004  *    is set, it's the string "~".
1005  * 3: The pattern \<ptrn\> does "word" searches, convert it to use the
1006  *    new RE escapes.
1007  *
1008  * !!!/XXX
1009  * This doesn't exactly match the historic behavior of vi because we do
1010  * the ~ substitution before calling the RE engine, so magic characters
1011  * in the replacement string will be expanded by the RE engine, and they
1012  * weren't historically.  It's a bug.
1013  */
1014 static int
1015 re_conv(SCR *sp, CHAR_T **ptrnp, size_t *plenp, int *replacedp)
1016 {
1017         size_t blen, len, needlen;
1018         int magic;
1019         CHAR_T *bp, *p, *t;
1020
1021         /*
1022          * First pass through, we figure out how much space we'll need.
1023          * We do it in two passes, on the grounds that most of the time
1024          * the user is doing a search and won't have magic characters.
1025          * That way we can skip most of the memory allocation and copies.
1026          */
1027         magic = 0;
1028         for (p = *ptrnp, len = *plenp, needlen = 0; len > 0; ++p, --len)
1029                 switch (*p) {
1030                 case '\\':
1031                         if (len > 1) {
1032                                 --len;
1033                                 switch (*++p) {
1034                                 case '<':
1035                                         magic = 1;
1036                                         needlen += RE_WSTART_LEN + 1;
1037                                         break;
1038                                 case '>':
1039                                         magic = 1;
1040                                         needlen += RE_WSTOP_LEN + 1;
1041                                         break;
1042                                 case '~':
1043                                         if (!O_ISSET(sp, O_MAGIC)) {
1044                                                 magic = 1;
1045                                                 needlen += sp->repl_len;
1046                                         }
1047                                         break;
1048                                 case '.':
1049                                 case '[':
1050                                 case '*':
1051                                         if (!O_ISSET(sp, O_MAGIC)) {
1052                                                 magic = 1;
1053                                                 needlen += 1;
1054                                         }
1055                                         break;
1056                                 default:
1057                                         needlen += 2;
1058                                 }
1059                         } else
1060                                 needlen += 1;
1061                         break;
1062                 case '~':
1063                         if (O_ISSET(sp, O_MAGIC)) {
1064                                 magic = 1;
1065                                 needlen += sp->repl_len;
1066                         }
1067                         break;
1068                 case '.':
1069                 case '[':
1070                 case '*':
1071                         if (!O_ISSET(sp, O_MAGIC)) {
1072                                 magic = 1;
1073                                 needlen += 2;
1074                         }
1075                         break;
1076                 default:
1077                         needlen += 1;
1078                         break;
1079                 }
1080
1081         if (!magic) {
1082                 *replacedp = 0;
1083                 return (0);
1084         }
1085
1086         /* Get enough memory to hold the final pattern. */
1087         *replacedp = 1;
1088         GET_SPACE_RETW(sp, bp, blen, needlen);
1089
1090         for (p = *ptrnp, len = *plenp, t = bp; len > 0; ++p, --len)
1091                 switch (*p) {
1092                 case '\\':
1093                         if (len > 1) {
1094                                 --len;
1095                                 switch (*++p) {
1096                                 case '<':
1097                                         MEMCPY(t,
1098                                             RE_WSTART, RE_WSTART_LEN);
1099                                         t += RE_WSTART_LEN;
1100                                         break;
1101                                 case '>':
1102                                         MEMCPY(t,
1103                                             RE_WSTOP, RE_WSTOP_LEN);
1104                                         t += RE_WSTOP_LEN;
1105                                         break;
1106                                 case '~':
1107                                         if (O_ISSET(sp, O_MAGIC))
1108                                                 *t++ = '~';
1109                                         else {
1110                                                 MEMCPY(t,
1111                                                     sp->repl, sp->repl_len);
1112                                                 t += sp->repl_len;
1113                                         }
1114                                         break;
1115                                 case '.':
1116                                 case '[':
1117                                 case '*':
1118                                         if (O_ISSET(sp, O_MAGIC))
1119                                                 *t++ = '\\';
1120                                         *t++ = *p;
1121                                         break;
1122                                 default:
1123                                         *t++ = '\\';
1124                                         *t++ = *p;
1125                                 }
1126                         } else
1127                                 *t++ = '\\';
1128                         break;
1129                 case '~':
1130                         if (O_ISSET(sp, O_MAGIC)) {
1131                                 MEMCPY(t, sp->repl, sp->repl_len);
1132                                 t += sp->repl_len;
1133                         } else
1134                                 *t++ = '~';
1135                         break;
1136                 case '.':
1137                 case '[':
1138                 case '*':
1139                         if (!O_ISSET(sp, O_MAGIC))
1140                                 *t++ = '\\';
1141                         *t++ = *p;
1142                         break;
1143                 default:
1144                         *t++ = *p;
1145                         break;
1146                 }
1147
1148         *ptrnp = bp;
1149         *plenp = t - bp;
1150         return (0);
1151 }
1152
1153 /*
1154  * re_tag_conv --
1155  *      Convert a tags search path into something that the POSIX
1156  *      1003.2 RE functions can handle.
1157  */
1158 static int
1159 re_tag_conv(SCR *sp, CHAR_T **ptrnp, size_t *plenp, int *replacedp)
1160 {
1161         size_t blen, len;
1162         int lastdollar;
1163         CHAR_T *bp, *p, *t;
1164
1165         len = *plenp;
1166
1167         /* Max memory usage is 2 times the length of the string. */
1168         *replacedp = 1;
1169         GET_SPACE_RETW(sp, bp, blen, len * 2);
1170
1171         p = *ptrnp;
1172         t = bp;
1173
1174         /* If the last character is a '/' or '?', we just strip it. */
1175         if (len > 0 && (p[len - 1] == '/' || p[len - 1] == '?'))
1176                 --len;
1177
1178         /* If the next-to-last or last character is a '$', it's magic. */
1179         if (len > 0 && p[len - 1] == '$') {
1180                 --len;
1181                 lastdollar = 1;
1182         } else
1183                 lastdollar = 0;
1184
1185         /* If the first character is a '/' or '?', we just strip it. */
1186         if (len > 0 && (p[0] == '/' || p[0] == '?')) {
1187                 ++p;
1188                 --len;
1189         }
1190
1191         /* If the first or second character is a '^', it's magic. */
1192         if (p[0] == '^') {
1193                 *t++ = *p++;
1194                 --len;
1195         }
1196
1197         /*
1198          * Escape every other magic character we can find, meanwhile stripping
1199          * the backslashes ctags inserts when escaping the search delimiter
1200          * characters.
1201          */
1202         for (; len > 0; --len) {
1203                 if (p[0] == '\\' && (p[1] == '/' || p[1] == '?')) {
1204                         ++p;
1205                         --len;
1206                 } else if (STRCHR(L("^.[]$*"), p[0]))
1207                         *t++ = '\\';
1208                 *t++ = *p++;
1209         }
1210         if (lastdollar)
1211                 *t++ = '$';
1212
1213         *ptrnp = bp;
1214         *plenp = t - bp;
1215         return (0);
1216 }
1217
1218 /*
1219  * re_cscope_conv --
1220  *       Convert a cscope search path into something that the POSIX
1221  *      1003.2 RE functions can handle.
1222  */
1223 static int
1224 re_cscope_conv(SCR *sp, CHAR_T **ptrnp, size_t *plenp, int *replacedp)
1225 {
1226         size_t blen, len, nspaces;
1227         CHAR_T *bp, *t;
1228         CHAR_T *p;
1229         CHAR_T *wp;
1230         size_t wlen;
1231
1232         /*
1233          * Each space in the source line printed by cscope represents an
1234          * arbitrary sequence of spaces, tabs, and comments.
1235          */
1236 #define CSCOPE_RE_SPACE         "([ \t]|/\\*([^*]|\\*/)*\\*/)*"
1237 #define CSCOPE_LEN      sizeof(CSCOPE_RE_SPACE) - 1
1238         CHAR2INT(sp, CSCOPE_RE_SPACE, CSCOPE_LEN, wp, wlen);
1239         for (nspaces = 0, p = *ptrnp, len = *plenp; len > 0; ++p, --len)
1240                 if (*p == ' ')
1241                         ++nspaces;
1242
1243         /*
1244          * Allocate plenty of space:
1245          *      the string, plus potential escaping characters;
1246          *      nspaces + 2 copies of CSCOPE_RE_SPACE;
1247          *      ^, $, nul terminator characters.
1248          */
1249         *replacedp = 1;
1250         len = (p - *ptrnp) * 2 + (nspaces + 2) * sizeof(CSCOPE_RE_SPACE) + 3;
1251         GET_SPACE_RETW(sp, bp, blen, len);
1252
1253         p = *ptrnp;
1254         t = bp;
1255
1256         *t++ = '^';
1257         MEMCPY(t, wp, wlen);
1258         t += wlen;
1259
1260         for (len = *plenp; len > 0; ++p, --len)
1261                 if (*p == ' ') {
1262                         MEMCPY(t, wp, wlen);
1263                         t += wlen;
1264                 } else {
1265                         if (STRCHR(L("\\^.[]$*+?()|{}"), *p))
1266                                 *t++ = '\\';
1267                         *t++ = *p;
1268                 }
1269
1270         MEMCPY(t, wp, wlen);
1271         t += wlen;
1272         *t++ = '$';
1273
1274         *ptrnp = bp;
1275         *plenp = t - bp;
1276         return (0);
1277 }
1278
1279 /*
1280  * re_error --
1281  *      Report a regular expression error.
1282  *
1283  * PUBLIC: void re_error(SCR *, int, regex_t *);
1284  */
1285 void
1286 re_error(SCR *sp, int errcode, regex_t *preg)
1287 {
1288         size_t s;
1289         char *oe;
1290
1291         s = regerror(errcode, preg, "", 0);
1292         MALLOC(sp, oe, char *, s);
1293         if (oe != NULL) {
1294                 (void)regerror(errcode, preg, oe, s);
1295                 msgq(sp, M_ERR, "RE error: %s", oe);
1296                 free(oe);
1297         }
1298 }
1299
1300 /*
1301  * re_sub --
1302  *      Do the substitution for a regular expression.
1303  */
1304 static int
1305 re_sub(
1306         SCR *sp,
1307         CHAR_T *ip,                     /* Input line. */
1308         CHAR_T **lbp,
1309         size_t *lbclenp,
1310         size_t *lblenp,
1311         regmatch_t match[10])
1312 {
1313         enum { C_NOTSET, C_LOWER, C_ONELOWER, C_ONEUPPER, C_UPPER } conv;
1314         size_t lbclen, lblen;           /* Local copies. */
1315         size_t mlen;                    /* Match length. */
1316         size_t rpl;                     /* Remaining replacement length. */
1317         CHAR_T *rp;                     /* Replacement pointer. */
1318         int ch;
1319         int no;                         /* Match replacement offset. */
1320         CHAR_T *p, *t;                  /* Buffer pointers. */
1321         CHAR_T *lb;                     /* Local copies. */
1322
1323         lb = *lbp;                      /* Get local copies. */
1324         lbclen = *lbclenp;
1325         lblen = *lblenp;
1326
1327         /*
1328          * QUOTING NOTE:
1329          *
1330          * There are some special sequences that vi provides in the
1331          * replacement patterns.
1332          *       & string the RE matched (\& if nomagic set)
1333          *      \# n-th regular subexpression
1334          *      \E end \U, \L conversion
1335          *      \e end \U, \L conversion
1336          *      \l convert the next character to lower-case
1337          *      \L convert to lower-case, until \E, \e, or end of replacement
1338          *      \u convert the next character to upper-case
1339          *      \U convert to upper-case, until \E, \e, or end of replacement
1340          *
1341          * Otherwise, since this is the lowest level of replacement, discard
1342          * all escaping characters.  This (hopefully) matches historic practice.
1343          */
1344 #define OUTCH(ch, nltrans) {                                            \
1345         ARG_CHAR_T __ch = (ch);                                         \
1346         e_key_t __value = KEY_VAL(sp, __ch);                            \
1347         if (nltrans && (__value == K_CR || __value == K_NL)) {          \
1348                 NEEDNEWLINE(sp);                                        \
1349                 sp->newl[sp->newl_cnt++] = lbclen;                      \
1350         } else if (conv != C_NOTSET) {                                  \
1351                 switch (conv) {                                         \
1352                 case C_ONELOWER:                                        \
1353                         conv = C_NOTSET;                                \
1354                         /* FALLTHROUGH */                               \
1355                 case C_LOWER:                                           \
1356                         if (ISUPPER(__ch))                              \
1357                                 __ch = TOLOWER(__ch);                   \
1358                         break;                                          \
1359                 case C_ONEUPPER:                                        \
1360                         conv = C_NOTSET;                                \
1361                         /* FALLTHROUGH */                               \
1362                 case C_UPPER:                                           \
1363                         if (ISLOWER(__ch))                              \
1364                                 __ch = TOUPPER(__ch);                   \
1365                         break;                                          \
1366                 default:                                                \
1367                         abort();                                        \
1368                 }                                                       \
1369         }                                                               \
1370         NEEDSP(sp, 1, p);                                               \
1371         *p++ = __ch;                                                    \
1372         ++lbclen;                                                       \
1373 }
1374         conv = C_NOTSET;
1375         for (rp = sp->repl, rpl = sp->repl_len, p = lb + lbclen; rpl--;) {
1376                 switch (ch = *rp++) {
1377                 case '&':
1378                         if (O_ISSET(sp, O_MAGIC)) {
1379                                 no = 0;
1380                                 goto subzero;
1381                         }
1382                         break;
1383                 case '\\':
1384                         if (rpl == 0)
1385                                 break;
1386                         --rpl;
1387                         switch (ch = *rp) {
1388                         case '&':
1389                                 ++rp;
1390                                 if (!O_ISSET(sp, O_MAGIC)) {
1391                                         no = 0;
1392                                         goto subzero;
1393                                 }
1394                                 break;
1395                         case '0': case '1': case '2': case '3': case '4':
1396                         case '5': case '6': case '7': case '8': case '9':
1397                                 no = *rp++ - '0';
1398 subzero:                        if (match[no].rm_so == -1 ||
1399                                     match[no].rm_eo == -1)
1400                                         break;
1401                                 mlen = match[no].rm_eo - match[no].rm_so;
1402                                 for (t = ip + match[no].rm_so; mlen--; ++t)
1403                                         OUTCH(*t, 0);
1404                                 continue;
1405                         case 'e':
1406                         case 'E':
1407                                 ++rp;
1408                                 conv = C_NOTSET;
1409                                 continue;
1410                         case 'l':
1411                                 ++rp;
1412                                 conv = C_ONELOWER;
1413                                 continue;
1414                         case 'L':
1415                                 ++rp;
1416                                 conv = C_LOWER;
1417                                 continue;
1418                         case 'u':
1419                                 ++rp;
1420                                 conv = C_ONEUPPER;
1421                                 continue;
1422                         case 'U':
1423                                 ++rp;
1424                                 conv = C_UPPER;
1425                                 continue;
1426                         case '\r':
1427                                 OUTCH(ch, 0);
1428                                 continue;
1429                         default:
1430                                 ++rp;
1431                                 break;
1432                         }
1433                 }
1434                 OUTCH(ch, 1);
1435         }
1436
1437         *lbp = lb;                      /* Update caller's information. */
1438         *lbclenp = lbclen;
1439         *lblenp = lblen;
1440         return (0);
1441 }