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 #include <sys/types.h>
  13 #include <sys/queue.h>
  14 #include <sys/time.h>
  15
  16 #include <bitstring.h>
  17 #include <ctype.h>
  18 #include <errno.h>
  19 #include <limits.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24
  25 #include "../common/common.h"
  26 #include "../vi/vi.h"
  27
  28 #define SUB_FIRST       0x01            /* The 'r' flag isn't reasonable. */
  29 #define SUB_MUSTSETR    0x02            /* The 'r' flag is required. */
  30
  31 static int re_conv(SCR *, CHAR_T **, size_t *, int *);
  32 static int re_cscope_conv(SCR *, CHAR_T **, size_t *, int *);
  33 static int re_sub(SCR *,
  34                 CHAR_T *, CHAR_T **, size_t *, size_t *, regmatch_t [10]);
  35 static int re_tag_conv(SCR *, CHAR_T **, size_t *, int *);
  36 static int s(SCR *, EXCMD *, CHAR_T *, regex_t *, u_int);
  37
  38 /*
  39  * ex_s --
  40  *      [line [,line]] s[ubstitute] [[/;]pat[/;]/repl[/;] [cgr] [count] [#lp]]
  41  *
  42  *      Substitute on lines matching a pattern.
  43  *
  44  * PUBLIC: int ex_s(SCR *, EXCMD *);
  45  */
  46 int
  47 ex_s(SCR *sp, EXCMD *cmdp)
  48 {
  49         regex_t *re;
  50         size_t blen, len;
  51         u_int flags;
  52         int delim;
  53         CHAR_T *bp, *p, *ptrn, *rep, *t;
  54
  55         /*
  56          * Skip leading white space.
  57          *
  58          * !!!
  59          * Historic vi allowed any non-alphanumeric to serve as the
  60          * substitution command delimiter.
  61          *
  62          * !!!
  63          * If the arguments are empty, it's the same as &, i.e. we
  64          * repeat the last substitution.
  65          */
  66         if (cmdp->argc == 0)
  67                 goto subagain;
  68         for (p = cmdp->argv[0]->bp,
  69             len = cmdp->argv[0]->len; len > 0; --len, ++p) {
  70                 if (!cmdskip(*p))
  71                         break;
  72         }
  73         if (len == 0)
  74 subagain:       return (ex_subagain(sp, cmdp));
  75
  76         delim = *p++;
  77         if (is09azAZ(delim) || delim == '\\')
  78                 return (s(sp, cmdp, p, &sp->subre_c, SUB_MUSTSETR));
  79
  80         /*
  81          * !!!
  82          * The full-blown substitute command reset the remembered
  83          * state of the 'c' and 'g' suffices.
  84          */
  85         sp->c_suffix = sp->g_suffix = 0;
  86
  87         /*
  88          * Get the pattern string, toss escaping characters.
  89          *
  90          * !!!
  91          * Historic vi accepted any of the following forms:
  92          *
  93          *      :s/abc/def/             change "abc" to "def"
  94          *      :s/abc/def              change "abc" to "def"
  95          *      :s/abc/                 delete "abc"
  96          *      :s/abc                  delete "abc"
  97          *
  98          * QUOTING NOTE:
  99          *
 100          * Only toss an escaping character if it escapes a delimiter.
 101          * This means that "s/A/\\\\f" replaces "A" with "\\f".  It
 102          * would be nice to be more regular, i.e. for each layer of
 103          * escaping a single escaping character is removed, but that's
 104          * not how the historic vi worked.
 105          */
 106         for (ptrn = t = p;;) {
 107                 if (p[0] == '\0' || p[0] == delim) {
 108                         if (p[0] == delim)
 109                                 ++p;
 110                         /*
 111                          * !!!
 112                          * Nul terminate the pattern string -- it's passed
 113                          * to regcomp which doesn't understand anything else.
 114                          */
 115                         *t = '\0';
 116                         break;
 117                 }
 118                 if (p[0] == '\\')
 119                         if (p[1] == delim)
 120                                 ++p;
 121                         else if (p[1] == '\\')
 122                                 *t++ = *p++;
 123                 *t++ = *p++;
 124         }
 125
 126         /*
 127          * If the pattern string is empty, use the last RE (not just the
 128          * last substitution RE).
 129          */
 130         if (*ptrn == '\0') {
 131                 if (sp->re == NULL) {
 132                         ex_emsg(sp, NULL, EXM_NOPREVRE);
 133                         return (1);
 134                 }
 135
 136                 /* Re-compile the RE if necessary. */
 137                 if (!F_ISSET(sp, SC_RE_SEARCH) &&
 138                     re_compile(sp, sp->re, sp->re_len,
 139                     NULL, NULL, &sp->re_c, RE_C_SEARCH))
 140                         return (1);
 141                 flags = 0;
 142         } else {
 143                 /*
 144                  * !!!
 145                  * Compile the RE.  Historic practice is that substitutes set
 146                  * the search direction as well as both substitute and search
 147                  * RE's.  We compile the RE twice, as we don't want to bother
 148                  * ref counting the pattern string and (opaque) structure.
 149                  */
 150                 if (re_compile(sp, ptrn, t - ptrn, &sp->re,
 151                     &sp->re_len, &sp->re_c, RE_C_SEARCH))
 152                         return (1);
 153                 if (re_compile(sp, ptrn, t - ptrn, &sp->subre,
 154                     &sp->subre_len, &sp->subre_c, RE_C_SUBST))
 155                         return (1);
 156
 157                 flags = SUB_FIRST;
 158                 sp->searchdir = FORWARD;
 159         }
 160         re = &sp->re_c;
 161
 162         /*
 163          * Get the replacement string.
 164          *
 165          * The special character & (\& if O_MAGIC not set) matches the
 166          * entire RE.  No handling of & is required here, it's done by
 167          * re_sub().
 168          *
 169          * The special character ~ (\~ if O_MAGIC not set) inserts the
 170          * previous replacement string into this replacement string.
 171          * Count ~'s to figure out how much space we need.  We could
 172          * special case nonexistent last patterns or whether or not
 173          * O_MAGIC is set, but it's probably not worth the effort.
 174          *
 175          * QUOTING NOTE:
 176          *
 177          * Only toss an escaping character if it escapes a delimiter or
 178          * if O_MAGIC is set and it escapes a tilde.
 179          *
 180          * !!!
 181          * If the entire replacement pattern is "%", then use the last
 182          * replacement pattern.  This semantic was added to vi in System
 183          * V and then percolated elsewhere, presumably around the time
 184          * that it was added to their version of ed(1).
 185          */
 186         if (p[0] == '\0' || p[0] == delim) {
 187                 if (p[0] == delim)
 188                         ++p;
 189                 free(sp->repl);
 190                 sp->repl = NULL;
 191                 sp->repl_len = 0;
 192         } else if (p[0] == '%' && (p[1] == '\0' || p[1] == delim))
 193                 p += p[1] == delim ? 2 : 1;
 194         else {
 195                 for (rep = p, len = 0;
 196                     p[0] != '\0' && p[0] != delim; ++p, ++len)
 197                         if (p[0] == '~')
 198                                 len += sp->repl_len;
 199                 GET_SPACE_RETW(sp, bp, blen, len);
 200                 for (t = bp, len = 0, p = rep;;) {
 201                         if (p[0] == '\0' || p[0] == delim) {
 202                                 if (p[0] == delim)
 203                                         ++p;
 204                                 break;
 205                         }
 206                         if (p[0] == '\\') {
 207                                 if (p[1] == delim)
 208                                         ++p;
 209                                 else if (p[1] == '\\') {
 210                                         *t++ = *p++;
 211                                         ++len;
 212                                 } else if (p[1] == '~') {
 213                                         ++p;
 214                                         if (!O_ISSET(sp, O_MAGIC))
 215                                                 goto tilde;
 216                                 }
 217                         } else if (p[0] == '~' && O_ISSET(sp, O_MAGIC)) {
 218 tilde:                          ++p;
 219                                 MEMCPY(t, sp->repl, sp->repl_len);
 220                                 t += sp->repl_len;
 221                                 len += sp->repl_len;
 222                                 continue;
 223                         }
 224                         *t++ = *p++;
 225                         ++len;
 226                 }
 227                 if ((sp->repl_len = len) != 0) {
 228                         free(sp->repl);
 229                         MALLOC(sp, sp->repl, len * sizeof(CHAR_T));
 230                         if (sp->repl == NULL) {
 231                                 FREE_SPACEW(sp, bp, blen);
 232                                 return (1);
 233                         }
 234                         MEMCPY(sp->repl, bp, len);
 235                 }
 236                 FREE_SPACEW(sp, bp, blen);
 237         }
 238         return (s(sp, cmdp, p, re, flags));
 239 }
 240
 241 /*
 242  * ex_subagain --
 243  *      [line [,line]] & [cgr] [count] [#lp]]
 244  *
 245  *      Substitute using the last substitute RE and replacement pattern.
 246  *
 247  * PUBLIC: int ex_subagain(SCR *, EXCMD *);
 248  */
 249 int
 250 ex_subagain(SCR *sp, EXCMD *cmdp)
 251 {
 252         if (sp->subre == NULL) {
 253                 ex_emsg(sp, NULL, EXM_NOPREVRE);
 254                 return (1);
 255         }
 256         if (!F_ISSET(sp, SC_RE_SUBST) &&
 257             re_compile(sp, sp->subre, sp->subre_len,
 258             NULL, NULL, &sp->subre_c, RE_C_SUBST))
 259                 return (1);
 260         return (s(sp,
 261             cmdp, cmdp->argc ? cmdp->argv[0]->bp : NULL, &sp->subre_c, 0));
 262 }
 263
 264 /*
 265  * ex_subtilde --
 266  *      [line [,line]] ~ [cgr] [count] [#lp]]
 267  *
 268  *      Substitute using the last RE and last substitute replacement pattern.
 269  *
 270  * PUBLIC: int ex_subtilde(SCR *, EXCMD *);
 271  */
 272 int
 273 ex_subtilde(SCR *sp, EXCMD *cmdp)
 274 {
 275         if (sp->re == NULL) {
 276                 ex_emsg(sp, NULL, EXM_NOPREVRE);
 277                 return (1);
 278         }
 279         if (!F_ISSET(sp, SC_RE_SEARCH) && re_compile(sp, sp->re,
 280             sp->re_len, NULL, NULL, &sp->re_c, RE_C_SEARCH))
 281                 return (1);
 282         return (s(sp,
 283             cmdp, cmdp->argc ? cmdp->argv[0]->bp : NULL, &sp->re_c, 0));
 284 }
 285
 286 /*
 287  * s --
 288  * Do the substitution.  This stuff is *really* tricky.  There are lots of
 289  * special cases, and general nastiness.  Don't mess with it unless you're
 290  * pretty confident.
 291  *
 292  * The nasty part of the substitution is what happens when the replacement
 293  * string contains newlines.  It's a bit tricky -- consider the information
 294  * that has to be retained for "s/f\(o\)o/^M\1^M\1/".  The solution here is
 295  * to build a set of newline offsets which we use to break the line up later,
 296  * when the replacement is done.  Don't change it unless you're *damned*
 297  * confident.
 298  */
 299 #define NEEDNEWLINE(sp) {                                               \
 300         if (sp->newl_len == sp->newl_cnt) {                             \
 301                 sp->newl_len += 25;                                     \
 302                 REALLOC(sp, sp->newl, size_t *,                         \
 303                     sp->newl_len * sizeof(size_t));                     \
 304                 if (sp->newl == NULL) {                                 \
 305                         sp->newl_len = 0;                               \
 306                         return (1);                                     \
 307                 }                                                       \
 308         }                                                               \
 309 }
 310
 311 #define BUILD(sp, l, len) {                                             \
 312         if (lbclen + (len) > lblen) {                                   \
 313                 lblen = p2roundup(MAX(lbclen + (len), 256));            \
 314                 REALLOC(sp, lb, CHAR_T *, lblen * sizeof(CHAR_T));      \
 315                 if (lb == NULL) {                                       \
 316                         lbclen = 0;                                     \
 317                         return (1);                                     \
 318                 }                                                       \
 319         }                                                               \
 320         MEMCPY(lb + lbclen, l, len);                                    \
 321         lbclen += len;                                                  \
 322 }
 323
 324 #define NEEDSP(sp, len, pnt) {                                          \
 325         if (lbclen + (len) > lblen) {                                   \
 326                 lblen = p2roundup(MAX(lbclen + (len), 256));            \
 327                 REALLOC(sp, lb, CHAR_T *, lblen * sizeof(CHAR_T));      \
 328                 if (lb == NULL) {                                       \
 329                         lbclen = 0;                                     \
 330                         return (1);                                     \
 331                 }                                                       \
 332                 pnt = lb + lbclen;                                      \
 333         }                                                               \
 334 }
 335
 336 static int
 337 s(SCR *sp, EXCMD *cmdp, CHAR_T *s, regex_t *re, u_int flags)
 338 {
 339         EVENT ev;
 340         MARK from, to;
 341         TEXTH tiq[] = {{ 0 }};
 342         recno_t elno, lno, slno;
 343         u_long ul;
 344         regmatch_t match[10];
 345         size_t blen, cnt, last, lbclen, lblen, len, llen;
 346         size_t offset, saved_offset, scno;
 347         int cflag, lflag, nflag, pflag, rflag;
 348         int didsub, do_eol_match, eflags, empty_ok, eval;
 349         int linechanged, matched, quit, rval;
 350         CHAR_T *bp, *lb;
 351         enum nresult nret;
 352
 353         NEEDFILE(sp, cmdp);
 354
 355         slno = sp->lno;
 356         scno = sp->cno;
 357
 358         /*
 359          * !!!
 360          * Historically, the 'g' and 'c' suffices were always toggled as flags,
 361          * so ":s/A/B/" was the same as ":s/A/B/ccgg".  If O_EDCOMPATIBLE was
 362          * not set, they were initialized to 0 for all substitute commands.  If
 363          * O_EDCOMPATIBLE was set, they were initialized to 0 only if the user
 364          * specified substitute/replacement patterns (see ex_s()).
 365          */
 366         if (!O_ISSET(sp, O_EDCOMPATIBLE))
 367                 sp->c_suffix = sp->g_suffix = 0;
 368
 369         /*
 370          * Historic vi permitted the '#', 'l' and 'p' options in vi mode, but
 371          * it only displayed the last change.  I'd disallow them, but they are
 372          * useful in combination with the [v]global commands.  In the current
 373          * model the problem is combining them with the 'c' flag -- the screen
 374          * would have to flip back and forth between the confirm screen and the
 375          * ex print screen, which would be pretty awful.  We do display all
 376          * changes, though, for what that's worth.
 377          *
 378          * !!!
 379          * Historic vi was fairly strict about the order of "options", the
 380          * count, and "flags".  I'm somewhat fuzzy on the difference between
 381          * options and flags, anyway, so this is a simpler approach, and we
 382          * just take it them in whatever order the user gives them.  (The ex
 383          * usage statement doesn't reflect this.)
 384          */
 385         cflag = lflag = nflag = pflag = rflag = 0;
 386         if (s == NULL)
 387                 goto noargs;
 388         for (lno = OOBLNO; *s != '\0'; ++s)
 389                 switch (*s) {
 390                 case ' ':
 391                 case '\t':
 392                         continue;
 393                 case '+':
 394                         ++cmdp->flagoff;
 395                         break;
 396                 case '-':
 397                         --cmdp->flagoff;
 398                         break;
 399                 case '0': case '1': case '2': case '3': case '4':
 400                 case '5': case '6': case '7': case '8': case '9':
 401                         if (lno != OOBLNO)
 402                                 goto usage;
 403                         errno = 0;
 404                         nret = nget_uslong(&ul, s, &s, 10);
 405                         lno = ul;
 406                         if (*s == '\0')         /* Loop increment correction. */
 407                                 --s;
 408                         if (nret != NUM_OK) {
 409                                 if (nret == NUM_OVER)
 410                                         msgq(sp, M_ERR, "153|Count overflow");
 411                                 else if (nret == NUM_UNDER)
 412                                         msgq(sp, M_ERR, "154|Count underflow");
 413                                 else
 414                                         msgq(sp, M_SYSERR, NULL);
 415                                 return (1);
 416                         }
 417                         /*
 418                          * In historic vi, the count was inclusive from the
 419                          * second address.
 420                          */
 421                         cmdp->addr1.lno = cmdp->addr2.lno;
 422                         cmdp->addr2.lno += lno - 1;
 423                         if (!db_exist(sp, cmdp->addr2.lno) &&
 424                             db_last(sp, &cmdp->addr2.lno))
 425                                 return (1);
 426                         break;
 427                 case '#':
 428                         nflag = 1;
 429                         break;
 430                 case 'c':
 431                         sp->c_suffix = !sp->c_suffix;
 432
 433                         /* Ex text structure initialization. */
 434                         if (F_ISSET(sp, SC_EX))
 435                                 TAILQ_INIT(tiq);
 436                         break;
 437                 case 'g':
 438                         sp->g_suffix = !sp->g_suffix;
 439                         break;
 440                 case 'l':
 441                         lflag = 1;
 442                         break;
 443                 case 'p':
 444                         pflag = 1;
 445                         break;
 446                 case 'r':
 447                         if (LF_ISSET(SUB_FIRST)) {
 448                                 msgq(sp, M_ERR,
 449                     "155|Regular expression specified; r flag meaningless");
 450                                 return (1);
 451                         }
 452                         if (!F_ISSET(sp, SC_RE_SEARCH)) {
 453                                 ex_emsg(sp, NULL, EXM_NOPREVRE);
 454                                 return (1);
 455                         }
 456                         rflag = 1;
 457                         re = &sp->re_c;
 458                         break;
 459                 default:
 460                         goto usage;
 461                 }
 462
 463         if (*s != '\0' || (!rflag && LF_ISSET(SUB_MUSTSETR))) {
 464 usage:          ex_emsg(sp, cmdp->cmd->usage, EXM_USAGE);
 465                 return (1);
 466         }
 467
 468 noargs: if (F_ISSET(sp, SC_VI) && sp->c_suffix && (lflag || nflag || pflag)) {
 469                 msgq(sp, M_ERR,
 470 "156|The #, l and p flags may not be combined with the c flag in vi mode");
 471                 return (1);
 472         }
 473
 474         /*
 475          * bp:          if interactive, line cache
 476          * blen:        if interactive, line cache length
 477          * lb:          build buffer pointer.
 478          * lbclen:      current length of built buffer.
 479          * lblen;       length of build buffer.
 480          */
 481         bp = lb = NULL;
 482         blen = lbclen = lblen = 0;
 483
 484         /* For each line... */
 485         lno = cmdp->addr1.lno == 0 ? 1 : cmdp->addr1.lno;
 486         for (matched = quit = 0,
 487             elno = cmdp->addr2.lno; !quit && lno <= elno; ++lno) {
 488
 489                 /* Someone's unhappy, time to stop. */
 490                 if (INTERRUPTED(sp))
 491                         break;
 492
 493                 /* Get the line. */
 494                 if (db_get(sp, lno, DBG_FATAL, &s, &llen))
 495                         goto err;
 496
 497                 /*
 498                  * Make a local copy if doing confirmation -- when calling
 499                  * the confirm routine we're likely to lose the cached copy.
 500                  */
 501                 if (sp->c_suffix) {
 502                         if (bp == NULL) {
 503                                 GET_SPACE_RETW(sp, bp, blen, llen);
 504                         } else
 505                                 ADD_SPACE_RETW(sp, bp, blen, llen);
 506                         MEMCPY(bp, s, llen);
 507                         s = bp;
 508                 }
 509
 510                 /* Start searching from the beginning. */
 511                 offset = 0;
 512                 len = llen;
 513
 514                 /* Reset the build buffer offset. */
 515                 lbclen = 0;
 516
 517                 /* Reset empty match flag. */
 518                 empty_ok = 1;
 519
 520                 /*
 521                  * We don't want to have to do a setline if the line didn't
 522                  * change -- keep track of whether or not this line changed.
 523                  * If doing confirmations, don't want to keep setting the
 524                  * line if change is refused -- keep track of substitutions.
 525                  */
 526                 didsub = linechanged = 0;
 527
 528                 /* New line, do an EOL match. */
 529                 do_eol_match = 1;
 530
 531                 /* It's not nul terminated, but we pretend it is. */
 532                 eflags = REG_STARTEND;
 533
 534                 /*
 535                  * The search area is from s + offset to the EOL.
 536                  *
 537                  * Generally, match[0].rm_so is the offset of the start
 538                  * of the match from the start of the search, and offset
 539                  * is the offset of the start of the last search.
 540                  */
 541 nextmatch:      match[0].rm_so = 0;
 542                 match[0].rm_eo = len;
 543
 544                 /* Get the next match. */
 545                 eval = regexec(re, s + offset, 10, match, eflags);
 546
 547                 /*
 548                  * There wasn't a match or if there was an error, deal with
 549                  * it.  If there was a previous match in this line, resolve
 550                  * the changes into the database.  Otherwise, just move on.
 551                  */
 552                 if (eval == REG_NOMATCH)
 553                         goto endmatch;
 554                 if (eval != 0) {
 555                         re_error(sp, eval, re);
 556                         goto err;
 557                 }
 558                 matched = 1;
 559
 560                 /* Only the first search can match an anchored expression. */
 561                 eflags |= REG_NOTBOL;
 562
 563                 /*
 564                  * !!!
 565                  * It's possible to match 0-length strings -- for example, the
 566                  * command s;a*;X;, when matched against the string "aabb" will
 567                  * result in "XbXbX", i.e. the matches are "aa", the space
 568                  * between the b's and the space between the b's and the end of
 569                  * the string.  There is a similar space between the beginning
 570                  * of the string and the a's.  The rule that we use (because vi
 571                  * historically used it) is that any 0-length match, occurring
 572                  * immediately after a match, is ignored.  Otherwise, the above
 573                  * example would have resulted in "XXbXbX".  Another example is
 574                  * incorrectly using " *" to replace groups of spaces with one
 575                  * space.
 576                  *
 577                  * The way we do this is that if we just had a successful match,
 578                  * the starting offset does not skip characters, and the match
 579                  * is empty, ignore the match and move forward.  If there's no
 580                  * more characters in the string, we were attempting to match
 581                  * after the last character, so quit.
 582                  */
 583                 if (!empty_ok && match[0].rm_so == 0 && match[0].rm_eo == 0) {
 584                         empty_ok = 1;
 585                         if (len == 0)
 586                                 goto endmatch;
 587                         BUILD(sp, s + offset, 1)
 588                         ++offset;
 589                         --len;
 590                         goto nextmatch;
 591                 }
 592
 593                 /* Confirm change. */
 594                 if (sp->c_suffix) {
 595                         /*
 596                          * Set the cursor position for confirmation.  Note,
 597                          * if we matched on a '$', the cursor may be past
 598                          * the end of line.
 599                          */
 600                         from.lno = to.lno = lno;
 601                         from.cno = match[0].rm_so + offset;
 602                         to.cno = match[0].rm_eo + offset;
 603                         /*
 604                          * Both ex and vi have to correct for a change before
 605                          * the first character in the line.
 606                          */
 607                         if (llen == 0)
 608                                 from.cno = to.cno = 0;
 609                         if (F_ISSET(sp, SC_VI)) {
 610                                 /*
 611                                  * Only vi has to correct for a change after
 612                                  * the last character in the line.
 613                                  *
 614                                  * XXX
 615                                  * It would be nice to change the vi code so
 616                                  * that we could display a cursor past EOL.
 617                                  */
 618                                 if (to.cno >= llen)
 619                                         to.cno = llen - 1;
 620                                 if (from.cno >= llen)
 621                                         from.cno = llen - 1;
 622
 623                                 sp->lno = from.lno;
 624                                 sp->cno = from.cno;
 625                                 if (vs_refresh(sp, 1))
 626                                         goto err;
 627
 628                                 vs_update(sp, msg_cat(sp,
 629                                     "169|Confirm change? [n]", NULL), NULL);
 630
 631                                 if (v_event_get(sp, &ev, 0, 0))
 632                                         goto err;
 633                                 switch (ev.e_event) {
 634                                 case E_CHARACTER:
 635                                         break;
 636                                 case E_EOF:
 637                                 case E_ERR:
 638                                 case E_INTERRUPT:
 639                                         goto lquit;
 640                                 default:
 641                                         v_event_err(sp, &ev);
 642                                         goto lquit;
 643                                 }
 644                         } else {
 645                                 if (ex_print(sp, cmdp, &from, &to, 0) ||
 646                                     ex_scprint(sp, &from, &to))
 647                                         goto lquit;
 648                                 if (ex_txt(sp, tiq, 0, TXT_CR))
 649                                         goto err;
 650                                 ev.e_c = TAILQ_FIRST(tiq)->lb[0];
 651                         }
 652
 653                         switch (ev.e_c) {
 654                         case CH_YES:
 655                                 break;
 656                         default:
 657                         case CH_NO:
 658                                 didsub = 0;
 659                                 BUILD(sp, s +offset, match[0].rm_eo);
 660                                 goto skip;
 661                         case CH_QUIT:
 662                                 /* Set the quit/interrupted flags. */
 663 lquit:                          quit = 1;
 664                                 F_SET(sp->gp, G_INTERRUPTED);
 665
 666                                 /*
 667                                  * Resolve any changes, then return to (and
 668                                  * exit from) the main loop.
 669                                  */
 670                                 goto endmatch;
 671                         }
 672                 }
 673
 674                 /*
 675                  * Set the cursor to the last position changed, converting
 676                  * from 1-based to 0-based.
 677                  */
 678                 sp->lno = lno;
 679                 sp->cno = match[0].rm_so;
 680
 681                 /* Copy the bytes before the match into the build buffer. */
 682                 BUILD(sp, s + offset, match[0].rm_so);
 683
 684                 /* Substitute the matching bytes. */
 685                 didsub = 1;
 686                 if (re_sub(sp, s + offset, &lb, &lbclen, &lblen, match))
 687                         goto err;
 688
 689                 /* Set the change flag so we know this line was modified. */
 690                 linechanged = 1;
 691
 692                 /* Move past the matched bytes. */
 693 skip:           offset += match[0].rm_eo;
 694                 len -= match[0].rm_eo;
 695
 696                 /* A match cannot be followed by an empty pattern. */
 697                 empty_ok = 0;
 698
 699                 /*
 700                  * If doing a global change with confirmation, we have to
 701                  * update the screen.  The basic idea is to store the line
 702                  * so the screen update routines can find it, and restart.
 703                  */
 704                 if (didsub && sp->c_suffix && sp->g_suffix) {
 705                         /*
 706                          * The new search offset will be the end of the
 707                          * modified line.
 708                          */
 709                         saved_offset = lbclen;
 710
 711                         /* Copy the rest of the line. */
 712                         if (len)
 713                                 BUILD(sp, s + offset, len)
 714
 715                         /* Set the new offset. */
 716                         offset = saved_offset;
 717
 718                         /* Store inserted lines, adjusting the build buffer. */
 719                         last = 0;
 720                         if (sp->newl_cnt) {
 721                                 for (cnt = 0;
 722                                     cnt < sp->newl_cnt; ++cnt, ++lno, ++elno) {
 723                                         if (db_insert(sp, lno,
 724                                             lb + last, sp->newl[cnt] - last))
 725                                                 goto err;
 726                                         last = sp->newl[cnt] + 1;
 727                                         ++sp->rptlines[L_ADDED];
 728                                 }
 729                                 lbclen -= last;
 730                                 offset -= last;
 731                                 sp->newl_cnt = 0;
 732                         }
 733
 734                         /* Store and retrieve the line. */
 735                         if (db_set(sp, lno, lb + last, lbclen))
 736                                 goto err;
 737                         if (db_get(sp, lno, DBG_FATAL, &s, &llen))
 738                                 goto err;
 739                         ADD_SPACE_RETW(sp, bp, blen, llen)
 740                         MEMCPY(bp, s, llen);
 741                         s = bp;
 742                         len = llen - offset;
 743
 744                         /* Restart the build. */
 745                         lbclen = 0;
 746                         BUILD(sp, s, offset);
 747
 748                         /*
 749                          * If we haven't already done the after-the-string
 750                          * match, do one.  Set REG_NOTEOL so the '$' pattern
 751                          * only matches once.
 752                          */
 753                         if (!do_eol_match)
 754                                 goto endmatch;
 755                         if (offset == len) {
 756                                 do_eol_match = 0;
 757                                 eflags |= REG_NOTEOL;
 758                         }
 759                         goto nextmatch;
 760                 }
 761
 762                 /*
 763                  * If it's a global:
 764                  *
 765                  * If at the end of the string, do a test for the after
 766                  * the string match.  Set REG_NOTEOL so the '$' pattern
 767                  * only matches once.
 768                  */
 769                 if (sp->g_suffix && do_eol_match) {
 770                         if (len == 0) {
 771                                 do_eol_match = 0;
 772                                 eflags |= REG_NOTEOL;
 773                         }
 774                         goto nextmatch;
 775                 }
 776
 777 endmatch:       if (!linechanged)
 778                         continue;
 779
 780                 /* Copy any remaining bytes into the build buffer. */
 781                 if (len)
 782                         BUILD(sp, s + offset, len)
 783
 784                 /* Store inserted lines, adjusting the build buffer. */
 785                 last = 0;
 786                 if (sp->newl_cnt) {
 787                         for (cnt = 0;
 788                             cnt < sp->newl_cnt; ++cnt, ++lno, ++elno) {
 789                                 if (db_insert(sp,
 790                                     lno, lb + last, sp->newl[cnt] - last))
 791                                         goto err;
 792                                 last = sp->newl[cnt] + 1;
 793                                 ++sp->rptlines[L_ADDED];
 794                         }
 795                         lbclen -= last;
 796                         sp->newl_cnt = 0;
 797                 }
 798
 799                 /* Store the changed line. */
 800                 if (db_set(sp, lno, lb + last, lbclen))
 801                         goto err;
 802
 803                 /* Update changed line counter. */
 804                 if (sp->rptlchange != lno) {
 805                         sp->rptlchange = lno;
 806                         ++sp->rptlines[L_CHANGED];
 807                 }
 808
 809                 /*
 810                  * !!!
 811                  * Display as necessary.  Historic practice is to only
 812                  * display the last line of a line split into multiple
 813                  * lines.
 814                  */
 815                 if (lflag || nflag || pflag) {
 816                         from.lno = to.lno = lno;
 817                         from.cno = to.cno = 0;
 818                         if (lflag)
 819                                 (void)ex_print(sp, cmdp, &from, &to, E_C_LIST);
 820                         if (nflag)
 821                                 (void)ex_print(sp, cmdp, &from, &to, E_C_HASH);
 822                         if (pflag)
 823                                 (void)ex_print(sp, cmdp, &from, &to, E_C_PRINT);
 824                 }
 825         }
 826
 827         /*
 828          * !!!
 829          * Historically, vi attempted to leave the cursor at the same place if
 830          * the substitution was done at the current cursor position.  Otherwise
 831          * it moved it to the first non-blank of the last line changed.  There
 832          * were some problems: for example, :s/$/foo/ with the cursor on the
 833          * last character of the line left the cursor on the last character, or
 834          * the & command with multiple occurrences of the matching string in the
 835          * line usually left the cursor in a fairly random position.
 836          *
 837          * We try to do the same thing, with the exception that if the user is
 838          * doing substitution with confirmation, we move to the last line about
 839          * which the user was consulted, as opposed to the last line that they
 840          * actually changed.  This prevents a screen flash if the user doesn't
 841          * change many of the possible lines.
 842          */
 843         if (!sp->c_suffix && (sp->lno != slno || sp->cno != scno)) {
 844                 sp->cno = 0;
 845                 (void)nonblank(sp, sp->lno, &sp->cno);
 846         }
 847
 848         /*
 849          * If not in a global command, and nothing matched, say so.
 850          * Else, if none of the lines displayed, put something up.
 851          */
 852         rval = 0;
 853         if (!matched) {
 854                 if (!F_ISSET(sp, SC_EX_GLOBAL)) {
 855                         msgq(sp, M_ERR, "157|No match found");
 856                         goto err;
 857                 }
 858         } else if (!lflag && !nflag && !pflag)
 859                 F_SET(cmdp, E_AUTOPRINT);
 860
 861         if (0) {
 862 err:            rval = 1;
 863         }
 864
 865         if (bp != NULL)
 866                 FREE_SPACEW(sp, bp, blen);
 867         free(lb);
 868         return (rval);
 869 }
 870
 871 /*
 872  * re_compile --
 873  *      Compile the RE.
 874  *
 875  * PUBLIC: int re_compile(SCR *,
 876  * PUBLIC:     CHAR_T *, size_t, CHAR_T **, size_t *, regex_t *, u_int);
 877  */
 878 int
 879 re_compile(SCR *sp, CHAR_T *ptrn, size_t plen, CHAR_T **ptrnp, size_t *lenp, regex_t *rep, u_int flags)
 880 {
 881         size_t len;
 882         int reflags, replaced, rval;
 883         CHAR_T *p;
 884
 885         /* Set RE flags. */
 886         reflags = 0;
 887         if (!LF_ISSET(RE_C_CSCOPE | RE_C_TAG)) {
 888                 if (O_ISSET(sp, O_EXTENDED))
 889                         reflags |= REG_EXTENDED;
 890                 if (O_ISSET(sp, O_IGNORECASE))
 891                         reflags |= REG_ICASE;
 892                 if (O_ISSET(sp, O_ICLOWER)) {
 893                         for (p = ptrn, len = plen; len > 0; ++p, --len)
 894                                 if (ISUPPER(*p))
 895                                         break;
 896                         if (len == 0)
 897                                 reflags |= REG_ICASE;
 898                 }
 899         }
 900
 901         /* If we're replacing a saved value, clear the old one. */
 902         if (LF_ISSET(RE_C_SEARCH) && F_ISSET(sp, SC_RE_SEARCH)) {
 903                 regfree(&sp->re_c);
 904                 F_CLR(sp, SC_RE_SEARCH);
 905         }
 906         if (LF_ISSET(RE_C_SUBST) && F_ISSET(sp, SC_RE_SUBST)) {
 907                 regfree(&sp->subre_c);
 908                 F_CLR(sp, SC_RE_SUBST);
 909         }
 910
 911         /*
 912          * If we're saving the string, it's a pattern we haven't seen before,
 913          * so convert the vi-style RE's to POSIX 1003.2 RE's.  Save a copy for
 914          * later recompilation.   Free any previously saved value.
 915          */
 916         if (ptrnp != NULL) {
 917                 replaced = 0;
 918                 if (LF_ISSET(RE_C_CSCOPE)) {
 919                         if (re_cscope_conv(sp, &ptrn, &plen, &replaced))
 920                                 return (1);
 921                         /*
 922                          * XXX
 923                          * Currently, the match-any-<blank> expression used in
 924                          * re_cscope_conv() requires extended RE's.  This may
 925                          * not be right or safe.
 926                          */
 927                         reflags |= REG_EXTENDED;
 928                 } else if (LF_ISSET(RE_C_TAG)) {
 929                         if (re_tag_conv(sp, &ptrn, &plen, &replaced))
 930                                 return (1);
 931                 } else
 932                         if (re_conv(sp, &ptrn, &plen, &replaced))
 933                                 return (1);
 934
 935                 /* Discard previous pattern. */
 936                 free(*ptrnp);
 937                 *ptrnp = NULL;
 938
 939                 if (lenp != NULL)
 940                         *lenp = plen;
 941
 942                 /*
 943                  * Copy the string into allocated memory.
 944                  *
 945                  * XXX
 946                  * Regcomp isn't 8-bit clean, so the pattern is nul-terminated
 947                  * for now.  There's just no other solution.
 948                  */
 949                 MALLOC(sp, *ptrnp, (plen + 1) * sizeof(CHAR_T));
 950                 if (*ptrnp != NULL) {
 951                         MEMCPY(*ptrnp, ptrn, plen);
 952                         (*ptrnp)[plen] = '\0';
 953                 }
 954
 955                 /* Free up conversion-routine-allocated memory. */
 956                 if (replaced)
 957                         FREE_SPACEW(sp, ptrn, 0);
 958
 959                 if (*ptrnp == NULL)
 960                         return (1);
 961
 962                 ptrn = *ptrnp;
 963         }
 964
 965         /*
 966          * XXX
 967          * Regcomp isn't 8-bit clean, so we just lost if the pattern
 968          * contained a nul.  Bummer!
 969          */
 970         if ((rval = regcomp(rep, ptrn, /* plen, */ reflags)) != 0) {
 971                 if (!LF_ISSET(RE_C_SILENT))
 972                         re_error(sp, rval, rep);
 973                 return (1);
 974         }
 975
 976         if (LF_ISSET(RE_C_SEARCH))
 977                 F_SET(sp, SC_RE_SEARCH);
 978         if (LF_ISSET(RE_C_SUBST))
 979                 F_SET(sp, SC_RE_SUBST);
 980
 981         return (0);
 982 }
 983
 984 /*
 985  * re_conv --
 986  *      Convert vi's regular expressions into something that the
 987  *      the POSIX 1003.2 RE functions can handle.
 988  *
 989  * There are three conversions we make to make vi's RE's (specifically
 990  * the global, search, and substitute patterns) work with POSIX RE's.
 991  *
 992  * 1: If O_MAGIC is not set, strip backslashes from the magic character
 993  *    set (.[*~) that have them, and add them to the ones that don't.
 994  * 2: If O_MAGIC is not set, the string "\~" is replaced with the text
 995  *    from the last substitute command's replacement string.  If O_MAGIC
 996  *    is set, it's the string "~".
 997  * 3: The pattern \<ptrn\> does "word" searches, convert it to use the
 998  *    new RE escapes.
 999  *
1000  * !!!/XXX
1001  * This doesn't exactly match the historic behavior of vi because we do
1002  * the ~ substitution before calling the RE engine, so magic characters
1003  * in the replacement string will be expanded by the RE engine, and they
1004  * weren't historically.  It's a bug.
1005  */
1006 static int
1007 re_conv(SCR *sp, CHAR_T **ptrnp, size_t *plenp, int *replacedp)
1008 {
1009         size_t blen, len, needlen;
1010         int magic;
1011         CHAR_T *bp, *p, *t;
1012
1013         /*
1014          * First pass through, we figure out how much space we'll need.
1015          * We do it in two passes, on the grounds that most of the time
1016          * the user is doing a search and won't have magic characters.
1017          * That way we can skip most of the memory allocation and copies.
1018          */
1019         magic = 0;
1020         for (p = *ptrnp, len = *plenp, needlen = 0; len > 0; ++p, --len)
1021                 switch (*p) {
1022                 case '\\':
1023                         if (len > 1) {
1024                                 --len;
1025                                 switch (*++p) {
1026                                 case '<':
1027                                         magic = 1;
1028                                         needlen += RE_WSTART_LEN + 1;
1029                                         break;
1030                                 case '>':
1031                                         magic = 1;
1032                                         needlen += RE_WSTOP_LEN + 1;
1033                                         break;
1034                                 case '~':
1035                                         if (!O_ISSET(sp, O_MAGIC)) {
1036                                                 magic = 1;
1037                                                 needlen += sp->repl_len;
1038                                         }
1039                                         break;
1040                                 case '.':
1041                                 case '[':
1042                                 case '*':
1043                                         if (!O_ISSET(sp, O_MAGIC)) {
1044                                                 magic = 1;
1045                                                 needlen += 1;
1046                                         }
1047                                         break;
1048                                 default:
1049                                         needlen += 2;
1050                                 }
1051                         } else
1052                                 needlen += 1;
1053                         break;
1054                 case '~':
1055                         if (O_ISSET(sp, O_MAGIC)) {
1056                                 magic = 1;
1057                                 needlen += sp->repl_len;
1058                         }
1059                         break;
1060                 case '.':
1061                 case '[':
1062                 case '*':
1063                         if (!O_ISSET(sp, O_MAGIC)) {
1064                                 magic = 1;
1065                                 needlen += 2;
1066                         }
1067                         break;
1068                 default:
1069                         needlen += 1;
1070                         break;
1071                 }
1072
1073         if (!magic) {
1074                 *replacedp = 0;
1075                 return (0);
1076         }
1077
1078         /* Get enough memory to hold the final pattern. */
1079         *replacedp = 1;
1080         GET_SPACE_RETW(sp, bp, blen, needlen);
1081
1082         for (p = *ptrnp, len = *plenp, t = bp; len > 0; ++p, --len)
1083                 switch (*p) {
1084                 case '\\':
1085                         if (len > 1) {
1086                                 --len;
1087                                 switch (*++p) {
1088                                 case '<':
1089                                         MEMCPY(t,
1090                                             RE_WSTART, RE_WSTART_LEN);
1091                                         t += RE_WSTART_LEN;
1092                                         break;
1093                                 case '>':
1094                                         MEMCPY(t,
1095                                             RE_WSTOP, RE_WSTOP_LEN);
1096                                         t += RE_WSTOP_LEN;
1097                                         break;
1098                                 case '~':
1099                                         if (O_ISSET(sp, O_MAGIC))
1100                                                 *t++ = '~';
1101                                         else {
1102                                                 MEMCPY(t,
1103                                                     sp->repl, sp->repl_len);
1104                                                 t += sp->repl_len;
1105                                         }
1106                                         break;
1107                                 case '.':
1108                                 case '[':
1109                                 case '*':
1110                                         if (O_ISSET(sp, O_MAGIC))
1111                                                 *t++ = '\\';
1112                                         *t++ = *p;
1113                                         break;
1114                                 default:
1115                                         *t++ = '\\';
1116                                         *t++ = *p;
1117                                 }
1118                         } else
1119                                 *t++ = '\\';
1120                         break;
1121                 case '~':
1122                         if (O_ISSET(sp, O_MAGIC)) {
1123                                 MEMCPY(t, sp->repl, sp->repl_len);
1124                                 t += sp->repl_len;
1125                         } else
1126                                 *t++ = '~';
1127                         break;
1128                 case '.':
1129                 case '[':
1130                 case '*':
1131                         if (!O_ISSET(sp, O_MAGIC))
1132                                 *t++ = '\\';
1133                         *t++ = *p;
1134                         break;
1135                 default:
1136                         *t++ = *p;
1137                         break;
1138                 }
1139
1140         *ptrnp = bp;
1141         *plenp = t - bp;
1142         return (0);
1143 }
1144
1145 /*
1146  * re_tag_conv --
1147  *      Convert a tags search path into something that the POSIX
1148  *      1003.2 RE functions can handle.
1149  */
1150 static int
1151 re_tag_conv(SCR *sp, CHAR_T **ptrnp, size_t *plenp, int *replacedp)
1152 {
1153         size_t blen, len;
1154         int lastdollar;
1155         CHAR_T *bp, *p, *t;
1156
1157         len = *plenp;
1158
1159         /* Max memory usage is 2 times the length of the string. */
1160         *replacedp = 1;
1161         GET_SPACE_RETW(sp, bp, blen, len * 2);
1162
1163         p = *ptrnp;
1164         t = bp;
1165
1166         /* If the last character is a '/' or '?', we just strip it. */
1167         if (len > 0 && (p[len - 1] == '/' || p[len - 1] == '?'))
1168                 --len;
1169
1170         /* If the next-to-last or last character is a '$', it's magic. */
1171         if (len > 0 && p[len - 1] == '$') {
1172                 --len;
1173                 lastdollar = 1;
1174         } else
1175                 lastdollar = 0;
1176
1177         /* If the first character is a '/' or '?', we just strip it. */
1178         if (len > 0 && (p[0] == '/' || p[0] == '?')) {
1179                 ++p;
1180                 --len;
1181         }
1182
1183         /* If the first or second character is a '^', it's magic. */
1184         if (p[0] == '^') {
1185                 *t++ = *p++;
1186                 --len;
1187         }
1188
1189         /*
1190          * Escape every other magic character we can find, meanwhile stripping
1191          * the backslashes ctags inserts when escaping the search delimiter
1192          * characters.
1193          */
1194         for (; len > 0; --len) {
1195                 if (p[0] == '\\' && (p[1] == '/' || p[1] == '?')) {
1196                         ++p;
1197                         --len;
1198                 } else if (STRCHR(L("^.[]$*"), p[0]))
1199                         *t++ = '\\';
1200                 *t++ = *p++;
1201         }
1202         if (lastdollar)
1203                 *t++ = '$';
1204
1205         *ptrnp = bp;
1206         *plenp = t - bp;
1207         return (0);
1208 }
1209
1210 /*
1211  * re_cscope_conv --
1212  *       Convert a cscope search path into something that the POSIX
1213  *      1003.2 RE functions can handle.
1214  */
1215 static int
1216 re_cscope_conv(SCR *sp, CHAR_T **ptrnp, size_t *plenp, int *replacedp)
1217 {
1218         size_t blen, len, nspaces;
1219         CHAR_T *bp, *t;
1220         CHAR_T *p;
1221         CHAR_T *wp;
1222         size_t wlen;
1223
1224         /*
1225          * Each space in the source line printed by cscope represents an
1226          * arbitrary sequence of spaces, tabs, and comments.
1227          */
1228 #define CSCOPE_RE_SPACE         "([ \t]|/\\*([^*]|\\*/)*\\*/)*"
1229 #define CSCOPE_LEN      sizeof(CSCOPE_RE_SPACE) - 1
1230         CHAR2INT(sp, CSCOPE_RE_SPACE, CSCOPE_LEN, wp, wlen);
1231         for (nspaces = 0, p = *ptrnp, len = *plenp; len > 0; ++p, --len)
1232                 if (*p == ' ')
1233                         ++nspaces;
1234
1235         /*
1236          * Allocate plenty of space:
1237          *      the string, plus potential escaping characters;
1238          *      nspaces + 2 copies of CSCOPE_RE_SPACE;
1239          *      ^, $, nul terminator characters.
1240          */
1241         *replacedp = 1;
1242         len = (p - *ptrnp) * 2 + (nspaces + 2) * sizeof(CSCOPE_RE_SPACE) + 3;
1243         GET_SPACE_RETW(sp, bp, blen, len);
1244
1245         p = *ptrnp;
1246         t = bp;
1247
1248         *t++ = '^';
1249         MEMCPY(t, wp, wlen);
1250         t += wlen;
1251
1252         for (len = *plenp; len > 0; ++p, --len)
1253                 if (*p == ' ') {
1254                         MEMCPY(t, wp, wlen);
1255                         t += wlen;
1256                 } else {
1257                         if (STRCHR(L("\\^.[]$*+?()|{}"), *p))
1258                                 *t++ = '\\';
1259                         *t++ = *p;
1260                 }
1261
1262         MEMCPY(t, wp, wlen);
1263         t += wlen;
1264         *t++ = '$';
1265
1266         *ptrnp = bp;
1267         *plenp = t - bp;
1268         return (0);
1269 }
1270
1271 /*
1272  * re_error --
1273  *      Report a regular expression error.
1274  *
1275  * PUBLIC: void re_error(SCR *, int, regex_t *);
1276  */
1277 void
1278 re_error(SCR *sp, int errcode, regex_t *preg)
1279 {
1280         size_t s;
1281         char *oe;
1282
1283         s = regerror(errcode, preg, "", 0);
1284         MALLOC(sp, oe, s);
1285         if (oe != NULL) {
1286                 (void)regerror(errcode, preg, oe, s);
1287                 msgq(sp, M_ERR, "RE error: %s", oe);
1288                 free(oe);
1289         }
1290 }
1291
1292 /*
1293  * re_sub --
1294  *      Do the substitution for a regular expression.
1295  */
1296 static int
1297 re_sub(
1298         SCR *sp,
1299         CHAR_T *ip,                     /* Input line. */
1300         CHAR_T **lbp,
1301         size_t *lbclenp,
1302         size_t *lblenp,
1303         regmatch_t match[10])
1304 {
1305         enum { C_NOTSET, C_LOWER, C_ONELOWER, C_ONEUPPER, C_UPPER } conv;
1306         size_t lbclen, lblen;           /* Local copies. */
1307         size_t mlen;                    /* Match length. */
1308         size_t rpl;                     /* Remaining replacement length. */
1309         CHAR_T *rp;                     /* Replacement pointer. */
1310         int ch;
1311         int no;                         /* Match replacement offset. */
1312         CHAR_T *p, *t;                  /* Buffer pointers. */
1313         CHAR_T *lb;                     /* Local copies. */
1314
1315         lb = *lbp;                      /* Get local copies. */
1316         lbclen = *lbclenp;
1317         lblen = *lblenp;
1318
1319         /*
1320          * QUOTING NOTE:
1321          *
1322          * There are some special sequences that vi provides in the
1323          * replacement patterns.
1324          *       & string the RE matched (\& if nomagic set)
1325          *      \# n-th regular subexpression
1326          *      \E end \U, \L conversion
1327          *      \e end \U, \L conversion
1328          *      \l convert the next character to lower-case
1329          *      \L convert to lower-case, until \E, \e, or end of replacement
1330          *      \u convert the next character to upper-case
1331          *      \U convert to upper-case, until \E, \e, or end of replacement
1332          *
1333          * Otherwise, since this is the lowest level of replacement, discard
1334          * all escaping characters.  This (hopefully) matches historic practice.
1335          */
1336 #define OUTCH(ch, nltrans) {                                            \
1337         ARG_CHAR_T __ch = (ch);                                         \
1338         e_key_t __value = KEY_VAL(sp, __ch);                            \
1339         if (nltrans && (__value == K_CR || __value == K_NL)) {          \
1340                 NEEDNEWLINE(sp);                                        \
1341                 sp->newl[sp->newl_cnt++] = lbclen;                      \
1342         } else if (conv != C_NOTSET) {                                  \
1343                 switch (conv) {                                         \
1344                 case C_ONELOWER:                                        \
1345                         conv = C_NOTSET;                                \
1346                         /* FALLTHROUGH */                               \
1347                 case C_LOWER:                                           \
1348                         if (ISUPPER(__ch))                              \
1349                                 __ch = TOLOWER(__ch);                   \
1350                         break;                                          \
1351                 case C_ONEUPPER:                                        \
1352                         conv = C_NOTSET;                                \
1353                         /* FALLTHROUGH */                               \
1354                 case C_UPPER:                                           \
1355                         if (ISLOWER(__ch))                              \
1356                                 __ch = TOUPPER(__ch);                   \
1357                         break;                                          \
1358                 default:                                                \
1359                         abort();                                        \
1360                 }                                                       \
1361         }                                                               \
1362         NEEDSP(sp, 1, p);                                               \
1363         *p++ = __ch;                                                    \
1364         ++lbclen;                                                       \
1365 }
1366         conv = C_NOTSET;
1367         for (rp = sp->repl, rpl = sp->repl_len, p = lb + lbclen; rpl--;) {
1368                 switch (ch = *rp++) {
1369                 case '&':
1370                         if (O_ISSET(sp, O_MAGIC)) {
1371                                 no = 0;
1372                                 goto subzero;
1373                         }
1374                         break;
1375                 case '\\':
1376                         if (rpl == 0)
1377                                 break;
1378                         --rpl;
1379                         switch (ch = *rp) {
1380                         case '&':
1381                                 ++rp;
1382                                 if (!O_ISSET(sp, O_MAGIC)) {
1383                                         no = 0;
1384                                         goto subzero;
1385                                 }
1386                                 break;
1387                         case '0': case '1': case '2': case '3': case '4':
1388                         case '5': case '6': case '7': case '8': case '9':
1389                                 no = *rp++ - '0';
1390 subzero:                        if (match[no].rm_so == -1 ||
1391                                     match[no].rm_eo == -1)
1392                                         break;
1393                                 mlen = match[no].rm_eo - match[no].rm_so;
1394                                 for (t = ip + match[no].rm_so; mlen--; ++t)
1395                                         OUTCH(*t, 0);
1396                                 continue;
1397                         case 'e':
1398                         case 'E':
1399                                 ++rp;
1400                                 conv = C_NOTSET;
1401                                 continue;
1402                         case 'l':
1403                                 ++rp;
1404                                 conv = C_ONELOWER;
1405                                 continue;
1406                         case 'L':
1407                                 ++rp;
1408                                 conv = C_LOWER;
1409                                 continue;
1410                         case 'u':
1411                                 ++rp;
1412                                 conv = C_ONEUPPER;
1413                                 continue;
1414                         case 'U':
1415                                 ++rp;
1416                                 conv = C_UPPER;
1417                                 continue;
1418                         case '\r':
1419                                 OUTCH(ch, 0);
1420                                 continue;
1421                         default:
1422                                 ++rp;
1423                                 break;
1424                         }
1425                 }
1426                 OUTCH(ch, 1);
1427         }
1428
1429         *lbp = lb;                      /* Update caller's information. */
1430         *lbclenp = lbclen;
1431         *lblenp = lblen;
1432         return (0);
1433 }