regex/regcomp.c

   1 /*-
   2  * Copyright (c) 1992, 1993, 1994 Henry Spencer.
   3  * Copyright (c) 1992, 1993, 1994
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * This code is derived from software contributed to Berkeley by
   7  * Henry Spencer of the University of Toronto.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by the University of
  20  *      California, Berkeley and its contributors.
  21  * 4. Neither the name of the University nor the names of its contributors
  22  *    may be used to endorse or promote products derived from this software
  23  *    without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35  * SUCH DAMAGE.
  36  *
  37  *      @(#)regcomp.c   8.4 (Berkeley) 3/19/94
  38  */
  39
  40 #if defined(LIBC_SCCS) && !defined(lint)
  41 static char sccsid[] = "@(#)regcomp.c   8.4 (Berkeley) 3/19/94";
  42 #endif /* LIBC_SCCS and not lint */
  43
  44 #include <sys/types.h>
  45 #include <stdio.h>
  46 #include <string.h>
  47 #include <ctype.h>
  48 #include <limits.h>
  49 #include <stdlib.h>
  50 #include <regex.h>
  51
  52 #include "utils.h"
  53 #include "regex2.h"
  54
  55 #include "cclass.h"
  56 #include "cname.h"
  57
  58 /*
  59  * parse structure, passed up and down to avoid global variables and
  60  * other clumsinesses
  61  */
  62 struct parse {
  63         RCHAR_T *next;          /* next character in RE */
  64         RCHAR_T *end;           /* end of string (-> NUL normally) */
  65         int error;              /* has an error been seen? */
  66         sop *strip;             /* malloced strip */
  67         sopno ssize;            /* malloced strip size (allocated) */
  68         sopno slen;             /* malloced strip length (used) */
  69         int ncsalloc;           /* number of csets allocated */
  70         struct re_guts *g;
  71 #       define  NPAREN  10      /* we need to remember () 1-9 for back refs */
  72         sopno pbegin[NPAREN];   /* -> ( ([0] unused) */
  73         sopno pend[NPAREN];     /* -> ) ([0] unused) */
  74 };
  75
  76 /* ========= begin header generated by ./mkh ========= */
  77 #ifdef __cplusplus
  78 extern "C" {
  79 #endif
  80
  81 /* === regcomp.c === */
  82 static void p_ere __P((struct parse *p, int stop));
  83 static void p_ere_exp __P((struct parse *p));
  84 static void p_str __P((struct parse *p));
  85 static void p_bre __P((struct parse *p, int end1, int end2));
  86 static int p_simp_re __P((struct parse *p, int starordinary));
  87 static int p_count __P((struct parse *p));
  88 static void p_bracket __P((struct parse *p));
  89 static void p_b_term __P((struct parse *p, cset *cs));
  90 static void p_b_cclass __P((struct parse *p, cset *cs));
  91 static void p_b_eclass __P((struct parse *p, cset *cs));
  92 static char p_b_symbol __P((struct parse *p));
  93 static char p_b_coll_elem __P((struct parse *p, int endc));
  94 static char othercase __P((int ch));
  95 static void bothcases __P((struct parse *p, int ch));
  96 static void ordinary __P((struct parse *p, int ch));
  97 static void nonnewline __P((struct parse *p));
  98 static void repeat __P((struct parse *p, sopno start, int from, int to));
  99 static int seterr __P((struct parse *p, int e));
 100 static cset *allocset __P((struct parse *p));
 101 static void freeset __P((struct parse *p, cset *cs));
 102 static int freezeset __P((struct parse *p, cset *cs));
 103 static int firstch __P((struct parse *p, cset *cs));
 104 static int nch __P((struct parse *p, cset *cs));
 105 static void mcadd __P((struct parse *p, cset *cs, char *cp));
 106 static void mcsub __P((cset *cs, char *cp));
 107 static int mcin __P((cset *cs, char *cp));
 108 static char *mcfind __P((cset *cs, char *cp));
 109 static void mcinvert __P((struct parse *p, cset *cs));
 110 static void mccase __P((struct parse *p, cset *cs));
 111 static int isinsets __P((struct re_guts *g, int c));
 112 static int samesets __P((struct re_guts *g, int c1, int c2));
 113 static void categorize __P((struct parse *p, struct re_guts *g));
 114 static sopno dupl __P((struct parse *p, sopno start, sopno finish));
 115 static void doemit __P((struct parse *p, sop op, size_t opnd));
 116 static void doinsert __P((struct parse *p, sop op, size_t opnd, sopno pos));
 117 static void dofwd __P((struct parse *p, sopno pos, sop value));
 118 static void enlarge __P((struct parse *p, sopno size));
 119 static void stripsnug __P((struct parse *p, struct re_guts *g));
 120 static void findmust __P((struct parse *p, struct re_guts *g));
 121 static sopno pluscount __P((struct parse *p, struct re_guts *g));
 122
 123 #ifdef __cplusplus
 124 }
 125 #endif
 126 /* ========= end header generated by ./mkh ========= */
 127
 128 static RCHAR_T nuls[10];                /* place to point scanner in event of error */
 129
 130 /*
 131  * macros for use with parse structure
 132  * BEWARE:  these know that the parse structure is named `p' !!!
 133  */
 134 #define PEEK()  (*p->next)
 135 #define PEEK2() (*(p->next+1))
 136 #define MORE()  (p->next < p->end)
 137 #define MORE2() (p->next+1 < p->end)
 138 #define SEE(c)  (MORE() && PEEK() == (c))
 139 #define SEETWO(a, b)    (MORE() && MORE2() && PEEK() == (a) && PEEK2() == (b))
 140 #define EAT(c)  ((SEE(c)) ? (NEXT(), 1) : 0)
 141 #define EATTWO(a, b)    ((SEETWO(a, b)) ? (NEXT2(), 1) : 0)
 142 #define NEXT()  (p->next++)
 143 #define NEXT2() (p->next += 2)
 144 #define NEXTn(n)        (p->next += (n))
 145 #define GETNEXT()       (*p->next++)
 146 #define SETERROR(e)     seterr(p, (e))
 147 #define REQUIRE(co, e)  ((co) || SETERROR(e))
 148 #define MUSTSEE(c, e)   (REQUIRE(MORE() && PEEK() == (c), e))
 149 #define MUSTEAT(c, e)   (REQUIRE(MORE() && GETNEXT() == (c), e))
 150 #define MUSTNOTSEE(c, e)        (REQUIRE(!MORE() || PEEK() != (c), e))
 151 #define EMIT(op, sopnd) doemit(p, (sop)(op), (size_t)(sopnd))
 152 #define INSERT(op, pos) doinsert(p, (sop)(op), HERE()-(pos)+1, pos)
 153 #define AHEAD(pos)              dofwd(p, pos, HERE()-(pos))
 154 #define ASTERN(sop, pos)        EMIT(sop, HERE()-pos)
 155 #define HERE()          (p->slen)
 156 #define THERE()         (p->slen - 1)
 157 #define THERETHERE()    (p->slen - 2)
 158 #define DROP(n) (p->slen -= (n))
 159
 160 #ifndef NDEBUG
 161 static int never = 0;           /* for use in asserts; shuts lint up */
 162 #else
 163 #define never   0               /* some <assert.h>s have bugs too */
 164 #endif
 165
 166 /*
 167  - regcomp - interface for parser and compilation
 168  = extern int regcomp(regex_t *, const RCHAR_T *, int);
 169  = #define      REG_BASIC       0000
 170  = #define      REG_EXTENDED    0001
 171  = #define      REG_ICASE       0002
 172  = #define      REG_NOSUB       0004
 173  = #define      REG_NEWLINE     0010
 174  = #define      REG_NOSPEC      0020
 175  = #define      REG_PEND        0040
 176  = #define      REG_DUMP        0200
 177  */
 178 int                             /* 0 success, otherwise REG_something */
 179 regcomp(preg, pattern, cflags)
 180 regex_t *preg;
 181 const RCHAR_T *pattern;
 182 int cflags;
 183 {
 184         struct parse pa;
 185         register struct re_guts *g;
 186         register struct parse *p = &pa;
 187         register int i;
 188         register size_t len;
 189 #ifdef REDEBUG
 190 #       define  GOODFLAGS(f)    (f)
 191 #else
 192 #       define  GOODFLAGS(f)    ((f)&~REG_DUMP)
 193 #endif
 194
 195         cflags = GOODFLAGS(cflags);
 196         if ((cflags&REG_EXTENDED) && (cflags&REG_NOSPEC))
 197                 return(REG_INVARG);
 198
 199         if (cflags&REG_PEND) {
 200                 if (preg->re_endp < pattern)
 201                         return(REG_INVARG);
 202                 len = preg->re_endp - pattern;
 203         } else
 204                 len = STRLEN(pattern);
 205
 206         /* do the mallocs early so failure handling is easy */
 207         g = (struct re_guts *)malloc(sizeof(struct re_guts) +
 208                                                         (NC-1)*sizeof(cat_t));
 209         if (g == NULL)
 210                 return(REG_ESPACE);
 211         p->ssize = len/(size_t)2*(size_t)3 + (size_t)1; /* ugh */
 212         p->strip = (sop *)malloc(p->ssize * sizeof(sop));
 213         p->slen = 0;
 214         if (p->strip == NULL) {
 215                 free((char *)g);
 216                 return(REG_ESPACE);
 217         }
 218
 219         /* set things up */
 220         p->g = g;
 221         p->next = (RCHAR_T *)pattern;   /* convenience; we do not modify it */
 222         p->end = p->next + len;
 223         p->error = 0;
 224         p->ncsalloc = 0;
 225         for (i = 0; i < NPAREN; i++) {
 226                 p->pbegin[i] = 0;
 227                 p->pend[i] = 0;
 228         }
 229         g->csetsize = NC;
 230         g->sets = NULL;
 231         g->setbits = NULL;
 232         g->ncsets = 0;
 233         g->cflags = cflags;
 234         g->iflags = 0;
 235         g->nbol = 0;
 236         g->neol = 0;
 237         g->must = NULL;
 238         g->mlen = 0;
 239         g->nsub = 0;
 240 #if 0
 241         g->ncategories = 1;     /* category 0 is "everything else" */
 242         g->categories = &g->catspace[-(CHAR_MIN)];
 243         (void) memset((char *)g->catspace, 0, NC*sizeof(cat_t));
 244 #endif
 245         g->backrefs = 0;
 246
 247         /* do it */
 248         EMIT(OEND, 0);
 249         g->firststate = THERE();
 250         if (cflags&REG_EXTENDED)
 251                 p_ere(p, OUT);
 252         else if (cflags&REG_NOSPEC)
 253                 p_str(p);
 254         else
 255                 p_bre(p, OUT, OUT);
 256         EMIT(OEND, 0);
 257         g->laststate = THERE();
 258
 259         /* tidy up loose ends and fill things in */
 260         categorize(p, g);
 261         stripsnug(p, g);
 262         findmust(p, g);
 263         g->nplus = pluscount(p, g);
 264         g->magic = MAGIC2;
 265         preg->re_nsub = g->nsub;
 266         preg->re_g = g;
 267         preg->re_magic = MAGIC1;
 268 #ifndef REDEBUG
 269         /* not debugging, so can't rely on the assert() in regexec() */
 270         if (g->iflags&BAD)
 271                 SETERROR(REG_ASSERT);
 272 #endif
 273
 274         /* win or lose, we're done */
 275         if (p->error != 0)      /* lose */
 276                 regfree(preg);
 277         return(p->error);
 278 }
 279
 280 /*
 281  - p_ere - ERE parser top level, concatenation and alternation
 282  == static void p_ere(register struct parse *p, int stop);
 283  */
 284 static void
 285 p_ere(p, stop)
 286 register struct parse *p;
 287 int stop;                       /* character this ERE should end at */
 288 {
 289         register char c;
 290         register sopno prevback;
 291         register sopno prevfwd;
 292         register sopno conc;
 293         register int first = 1;         /* is this the first alternative? */
 294
 295         for (;;) {
 296                 /* do a bunch of concatenated expressions */
 297                 conc = HERE();
 298                 while (MORE() && (c = PEEK()) != '|' && c != stop)
 299                         p_ere_exp(p);
 300                 REQUIRE(HERE() != conc, REG_EMPTY);     /* require nonempty */
 301
 302                 if (!EAT('|'))
 303                         break;          /* NOTE BREAK OUT */
 304
 305                 if (first) {
 306                         INSERT(OCH_, conc);     /* offset is wrong */
 307                         prevfwd = conc;
 308                         prevback = conc;
 309                         first = 0;
 310                 }
 311                 ASTERN(OOR1, prevback);
 312                 prevback = THERE();
 313                 AHEAD(prevfwd);                 /* fix previous offset */
 314                 prevfwd = HERE();
 315                 EMIT(OOR2, 0);                  /* offset is very wrong */
 316         }
 317
 318         if (!first) {           /* tail-end fixups */
 319                 AHEAD(prevfwd);
 320                 ASTERN(O_CH, prevback);
 321         }
 322
 323         assert(!MORE() || SEE(stop));
 324 }
 325
 326 /*
 327  - p_ere_exp - parse one subERE, an atom possibly followed by a repetition op
 328  == static void p_ere_exp(register struct parse *p);
 329  */
 330 static void
 331 p_ere_exp(p)
 332 register struct parse *p;
 333 {
 334         register char c;
 335         register sopno pos;
 336         register int count;
 337         register int count2;
 338         register sopno subno;
 339         int wascaret = 0;
 340
 341         assert(MORE());         /* caller should have ensured this */
 342         c = GETNEXT();
 343
 344         pos = HERE();
 345         switch (c) {
 346         case '(':
 347                 REQUIRE(MORE(), REG_EPAREN);
 348                 p->g->nsub++;
 349                 subno = p->g->nsub;
 350                 if (subno < NPAREN)
 351                         p->pbegin[subno] = HERE();
 352                 EMIT(OLPAREN, subno);
 353                 if (!SEE(')'))
 354                         p_ere(p, ')');
 355                 if (subno < NPAREN) {
 356                         p->pend[subno] = HERE();
 357                         assert(p->pend[subno] != 0);
 358                 }
 359                 EMIT(ORPAREN, subno);
 360                 MUSTEAT(')', REG_EPAREN);
 361                 break;
 362 #ifndef POSIX_MISTAKE
 363         case ')':               /* happens only if no current unmatched ( */
 364                 /*
 365                  * You may ask, why the ifndef?  Because I didn't notice
 366                  * this until slightly too late for 1003.2, and none of the
 367                  * other 1003.2 regular-expression reviewers noticed it at
 368                  * all.  So an unmatched ) is legal POSIX, at least until
 369                  * we can get it fixed.
 370                  */
 371                 SETERROR(REG_EPAREN);
 372                 break;
 373 #endif
 374         case '^':
 375                 EMIT(OBOL, 0);
 376                 p->g->iflags |= USEBOL;
 377                 p->g->nbol++;
 378                 wascaret = 1;
 379                 break;
 380         case '$':
 381                 EMIT(OEOL, 0);
 382                 p->g->iflags |= USEEOL;
 383                 p->g->neol++;
 384                 break;
 385         case '|':
 386                 SETERROR(REG_EMPTY);
 387                 break;
 388         case '*':
 389         case '+':
 390         case '?':
 391                 SETERROR(REG_BADRPT);
 392                 break;
 393         case '.':
 394                 if (p->g->cflags&REG_NEWLINE)
 395                         nonnewline(p);
 396                 else
 397                         EMIT(OANY, 0);
 398                 break;
 399         case '[':
 400                 p_bracket(p);
 401                 break;
 402         case '\\':
 403                 REQUIRE(MORE(), REG_EESCAPE);
 404                 c = GETNEXT();
 405                 ordinary(p, c);
 406                 break;
 407         case '{':               /* okay as ordinary except if digit follows */
 408                 REQUIRE(!MORE() || !isdigit(PEEK()), REG_BADRPT);
 409                 /* FALLTHROUGH */
 410         default:
 411                 ordinary(p, c);
 412                 break;
 413         }
 414
 415         if (!MORE())
 416                 return;
 417         c = PEEK();
 418         /* we call { a repetition if followed by a digit */
 419         if (!( c == '*' || c == '+' || c == '?' ||
 420                                 (c == '{' && MORE2() && isdigit(PEEK2())) ))
 421                 return;         /* no repetition, we're done */
 422         NEXT();
 423
 424         REQUIRE(!wascaret, REG_BADRPT);
 425         switch (c) {
 426         case '*':       /* implemented as +? */
 427                 /* this case does not require the (y|) trick, noKLUDGE */
 428                 INSERT(OPLUS_, pos);
 429                 ASTERN(O_PLUS, pos);
 430                 INSERT(OQUEST_, pos);
 431                 ASTERN(O_QUEST, pos);
 432                 break;
 433         case '+':
 434                 INSERT(OPLUS_, pos);
 435                 ASTERN(O_PLUS, pos);
 436                 break;
 437         case '?':
 438                 /* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
 439                 INSERT(OCH_, pos);              /* offset slightly wrong */
 440                 ASTERN(OOR1, pos);              /* this one's right */
 441                 AHEAD(pos);                     /* fix the OCH_ */
 442                 EMIT(OOR2, 0);                  /* offset very wrong... */
 443                 AHEAD(THERE());                 /* ...so fix it */
 444                 ASTERN(O_CH, THERETHERE());
 445                 break;
 446         case '{':
 447                 count = p_count(p);
 448                 if (EAT(',')) {
 449                         if (isdigit(PEEK())) {
 450                                 count2 = p_count(p);
 451                                 REQUIRE(count <= count2, REG_BADBR);
 452                         } else          /* single number with comma */
 453                                 count2 = INFINITY;
 454                 } else          /* just a single number */
 455                         count2 = count;
 456                 repeat(p, pos, count, count2);
 457                 if (!EAT('}')) {        /* error heuristics */
 458                         while (MORE() && PEEK() != '}')
 459                                 NEXT();
 460                         REQUIRE(MORE(), REG_EBRACE);
 461                         SETERROR(REG_BADBR);
 462                 }
 463                 break;
 464         }
 465
 466         if (!MORE())
 467                 return;
 468         c = PEEK();
 469         if (!( c == '*' || c == '+' || c == '?' ||
 470                                 (c == '{' && MORE2() && isdigit(PEEK2())) ) )
 471                 return;
 472         SETERROR(REG_BADRPT);
 473 }
 474
 475 /*
 476  - p_str - string (no metacharacters) "parser"
 477  == static void p_str(register struct parse *p);
 478  */
 479 static void
 480 p_str(p)
 481 register struct parse *p;
 482 {
 483         REQUIRE(MORE(), REG_EMPTY);
 484         while (MORE())
 485                 ordinary(p, GETNEXT());
 486 }
 487
 488 /*
 489  - p_bre - BRE parser top level, anchoring and concatenation
 490  == static void p_bre(register struct parse *p, register int end1, \
 491  ==     register int end2);
 492  * Giving end1 as OUT essentially eliminates the end1/end2 check.
 493  *
 494  * This implementation is a bit of a kludge, in that a trailing $ is first
 495  * taken as an ordinary character and then revised to be an anchor.  The
 496  * only undesirable side effect is that '$' gets included as a character
 497  * category in such cases.  This is fairly harmless; not worth fixing.
 498  * The amount of lookahead needed to avoid this kludge is excessive.
 499  */
 500 static void
 501 p_bre(p, end1, end2)
 502 register struct parse *p;
 503 register int end1;              /* first terminating character */
 504 register int end2;              /* second terminating character */
 505 {
 506         register sopno start = HERE();
 507         register int first = 1;                 /* first subexpression? */
 508         register int wasdollar = 0;
 509
 510         if (EAT('^')) {
 511                 EMIT(OBOL, 0);
 512                 p->g->iflags |= USEBOL;
 513                 p->g->nbol++;
 514         }
 515         while (MORE() && !SEETWO(end1, end2)) {
 516                 wasdollar = p_simp_re(p, first);
 517                 first = 0;
 518         }
 519         if (wasdollar) {        /* oops, that was a trailing anchor */
 520                 DROP(1);
 521                 EMIT(OEOL, 0);
 522                 p->g->iflags |= USEEOL;
 523                 p->g->neol++;
 524         }
 525
 526         REQUIRE(HERE() != start, REG_EMPTY);    /* require nonempty */
 527 }
 528
 529 /*
 530  - p_simp_re - parse a simple RE, an atom possibly followed by a repetition
 531  == static int p_simp_re(register struct parse *p, int starordinary);
 532  */
 533 static int                      /* was the simple RE an unbackslashed $? */
 534 p_simp_re(p, starordinary)
 535 register struct parse *p;
 536 int starordinary;               /* is a leading * an ordinary character? */
 537 {
 538         register int c;
 539         register int count;
 540         register int count2;
 541         register sopno pos;
 542         register int i;
 543         register sopno subno;
 544 #       define  BACKSL  (1<<RCHAR_BIT)
 545
 546         pos = HERE();           /* repetion op, if any, covers from here */
 547
 548         assert(MORE());         /* caller should have ensured this */
 549         c = GETNEXT();
 550         if (c == '\\') {
 551                 REQUIRE(MORE(), REG_EESCAPE);
 552                 c = BACKSL | (unsigned char)GETNEXT();
 553         }
 554         switch (c) {
 555         case '.':
 556                 if (p->g->cflags&REG_NEWLINE)
 557                         nonnewline(p);
 558                 else
 559                         EMIT(OANY, 0);
 560                 break;
 561         case '[':
 562                 p_bracket(p);
 563                 break;
 564         case BACKSL|'{':
 565                 SETERROR(REG_BADRPT);
 566                 break;
 567         case BACKSL|'(':
 568                 p->g->nsub++;
 569                 subno = p->g->nsub;
 570                 if (subno < NPAREN)
 571                         p->pbegin[subno] = HERE();
 572                 EMIT(OLPAREN, subno);
 573                 /* the MORE here is an error heuristic */
 574                 if (MORE() && !SEETWO('\\', ')'))
 575                         p_bre(p, '\\', ')');
 576                 if (subno < NPAREN) {
 577                         p->pend[subno] = HERE();
 578                         assert(p->pend[subno] != 0);
 579                 }
 580                 EMIT(ORPAREN, subno);
 581                 REQUIRE(EATTWO('\\', ')'), REG_EPAREN);
 582                 break;
 583         case BACKSL|')':        /* should not get here -- must be user */
 584         case BACKSL|'}':
 585                 SETERROR(REG_EPAREN);
 586                 break;
 587         case BACKSL|'1':
 588         case BACKSL|'2':
 589         case BACKSL|'3':
 590         case BACKSL|'4':
 591         case BACKSL|'5':
 592         case BACKSL|'6':
 593         case BACKSL|'7':
 594         case BACKSL|'8':
 595         case BACKSL|'9':
 596                 i = (c&~BACKSL) - '0';
 597                 assert(i < NPAREN);
 598                 if (p->pend[i] != 0) {
 599                         assert(i <= p->g->nsub);
 600                         EMIT(OBACK_, i);
 601                         assert(p->pbegin[i] != 0);
 602                         assert(OP(p->strip[p->pbegin[i]]) == OLPAREN);
 603                         assert(OP(p->strip[p->pend[i]]) == ORPAREN);
 604                         (void) dupl(p, p->pbegin[i]+1, p->pend[i]);
 605                         EMIT(O_BACK, i);
 606                 } else
 607                         SETERROR(REG_ESUBREG);
 608                 p->g->backrefs = 1;
 609                 break;
 610         case '*':
 611                 REQUIRE(starordinary, REG_BADRPT);
 612                 /* FALLTHROUGH */
 613         default:
 614                 ordinary(p, c &~ BACKSL);
 615                 break;
 616         }
 617
 618         if (EAT('*')) {         /* implemented as +? */
 619                 /* this case does not require the (y|) trick, noKLUDGE */
 620                 INSERT(OPLUS_, pos);
 621                 ASTERN(O_PLUS, pos);
 622                 INSERT(OQUEST_, pos);
 623                 ASTERN(O_QUEST, pos);
 624         } else if (EATTWO('\\', '{')) {
 625                 count = p_count(p);
 626                 if (EAT(',')) {
 627                         if (MORE() && isdigit(PEEK())) {
 628                                 count2 = p_count(p);
 629                                 REQUIRE(count <= count2, REG_BADBR);
 630                         } else          /* single number with comma */
 631                                 count2 = INFINITY;
 632                 } else          /* just a single number */
 633                         count2 = count;
 634                 repeat(p, pos, count, count2);
 635                 if (!EATTWO('\\', '}')) {       /* error heuristics */
 636                         while (MORE() && !SEETWO('\\', '}'))
 637                                 NEXT();
 638                         REQUIRE(MORE(), REG_EBRACE);
 639                         SETERROR(REG_BADBR);
 640                 }
 641         } else if (c == (unsigned char)'$')     /* $ (but not \$) ends it */
 642                 return(1);
 643
 644         return(0);
 645 }
 646
 647 /*
 648  - p_count - parse a repetition count
 649  == static int p_count(register struct parse *p);
 650  */
 651 static int                      /* the value */
 652 p_count(p)
 653 register struct parse *p;
 654 {
 655         register int count = 0;
 656         register int ndigits = 0;
 657
 658         while (MORE() && isdigit(PEEK()) && count <= DUPMAX) {
 659                 count = count*10 + (GETNEXT() - '0');
 660                 ndigits++;
 661         }
 662
 663         REQUIRE(ndigits > 0 && count <= DUPMAX, REG_BADBR);
 664         return(count);
 665 }
 666
 667 /*
 668  - p_bracket - parse a bracketed character list
 669  == static void p_bracket(register struct parse *p);
 670  *
 671  * Note a significant property of this code:  if the allocset() did SETERROR,
 672  * no set operations are done.
 673  */
 674 static void
 675 p_bracket(p)
 676 register struct parse *p;
 677 {
 678         register char c;
 679         register cset *cs = allocset(p);
 680         register int invert = 0;
 681         static RCHAR_T bow[] = { '[', ':', '<', ':', ']', ']' };
 682         static RCHAR_T eow[] = { '[', ':', '>', ':', ']', ']' };
 683
 684         /* Dept of Truly Sickening Special-Case Kludges */
 685         if (p->next + 5 < p->end && MEMCMP(p->next, bow, 6) == 0) {
 686                 EMIT(OBOW, 0);
 687                 NEXTn(6);
 688                 return;
 689         }
 690         if (p->next + 5 < p->end && MEMCMP(p->next, eow, 6) == 0) {
 691                 EMIT(OEOW, 0);
 692                 NEXTn(6);
 693                 return;
 694         }
 695
 696         if (EAT('^'))
 697                 invert++;       /* make note to invert set at end */
 698         if (EAT(']'))
 699                 CHadd(cs, ']');
 700         else if (EAT('-'))
 701                 CHadd(cs, '-');
 702         while (MORE() && PEEK() != ']' && !SEETWO('-', ']'))
 703                 p_b_term(p, cs);
 704         if (EAT('-'))
 705                 CHadd(cs, '-');
 706         MUSTEAT(']', REG_EBRACK);
 707
 708         if (p->error != 0)      /* don't mess things up further */
 709                 return;
 710
 711         if (p->g->cflags&REG_ICASE) {
 712                 register int i;
 713                 register int ci;
 714
 715                 for (i = p->g->csetsize - 1; i >= 0; i--)
 716                         if (CHIN(cs, i) && isalpha(i)) {
 717                                 ci = othercase(i);
 718                                 if (ci != i)
 719                                         CHadd(cs, ci);
 720                         }
 721                 if (cs->multis != NULL)
 722                         mccase(p, cs);
 723         }
 724         if (invert) {
 725                 register int i;
 726
 727                 for (i = p->g->csetsize - 1; i >= 0; i--)
 728                         if (CHIN(cs, i))
 729                                 CHsub(cs, i);
 730                         else
 731                                 CHadd(cs, i);
 732                 if (p->g->cflags&REG_NEWLINE)
 733                         CHsub(cs, '\n');
 734                 if (cs->multis != NULL)
 735                         mcinvert(p, cs);
 736         }
 737
 738         assert(cs->multis == NULL);             /* xxx */
 739
 740         if (nch(p, cs) == 1) {          /* optimize singleton sets */
 741                 ordinary(p, firstch(p, cs));
 742                 freeset(p, cs);
 743         } else
 744                 EMIT(OANYOF, freezeset(p, cs));
 745 }
 746
 747 /*
 748  - p_b_term - parse one term of a bracketed character list
 749  == static void p_b_term(register struct parse *p, register cset *cs);
 750  */
 751 static void
 752 p_b_term(p, cs)
 753 register struct parse *p;
 754 register cset *cs;
 755 {
 756         register char c;
 757         register char start, finish;
 758         register int i;
 759
 760         /* classify what we've got */
 761         switch ((MORE()) ? PEEK() : '\0') {
 762         case '[':
 763                 c = (MORE2()) ? PEEK2() : '\0';
 764                 break;
 765         case '-':
 766                 SETERROR(REG_ERANGE);
 767                 return;                 /* NOTE RETURN */
 768                 break;
 769         default:
 770                 c = '\0';
 771                 break;
 772         }
 773
 774         switch (c) {
 775         case ':':               /* character class */
 776                 NEXT2();
 777                 REQUIRE(MORE(), REG_EBRACK);
 778                 c = PEEK();
 779                 REQUIRE(c != '-' && c != ']', REG_ECTYPE);
 780                 p_b_cclass(p, cs);
 781                 REQUIRE(MORE(), REG_EBRACK);
 782                 REQUIRE(EATTWO(':', ']'), REG_ECTYPE);
 783                 break;
 784         case '=':               /* equivalence class */
 785                 NEXT2();
 786                 REQUIRE(MORE(), REG_EBRACK);
 787                 c = PEEK();
 788                 REQUIRE(c != '-' && c != ']', REG_ECOLLATE);
 789                 p_b_eclass(p, cs);
 790                 REQUIRE(MORE(), REG_EBRACK);
 791                 REQUIRE(EATTWO('=', ']'), REG_ECOLLATE);
 792                 break;
 793         default:                /* symbol, ordinary character, or range */
 794 /* xxx revision needed for multichar stuff */
 795                 start = p_b_symbol(p);
 796                 if (SEE('-') && MORE2() && PEEK2() != ']') {
 797                         /* range */
 798                         NEXT();
 799                         if (EAT('-'))
 800                                 finish = '-';
 801                         else
 802                                 finish = p_b_symbol(p);
 803                 } else
 804                         finish = start;
 805 /* xxx what about signed chars here... */
 806                 REQUIRE(start <= finish, REG_ERANGE);
 807                 for (i = start; i <= finish; i++)
 808                         CHadd(cs, i);
 809                 break;
 810         }
 811 }
 812
 813 /*
 814  - p_b_cclass - parse a character-class name and deal with it
 815  == static void p_b_cclass(register struct parse *p, register cset *cs);
 816  */
 817 static void
 818 p_b_cclass(p, cs)
 819 register struct parse *p;
 820 register cset *cs;
 821 {
 822         register RCHAR_T *sp = p->next;
 823         register struct cclass *cp;
 824         register size_t len;
 825         register char *u;
 826         register char c;
 827
 828         while (MORE() && isalpha(PEEK()))
 829                 NEXT();
 830         len = p->next - sp;
 831         for (cp = cclasses; cp->name != NULL; cp++)
 832                 if (STRLEN(cp->name) == len && MEMCMP(cp->name, sp, len))
 833                         break;
 834         if (cp->name == NULL) {
 835                 /* oops, didn't find it */
 836                 SETERROR(REG_ECTYPE);
 837                 return;
 838         }
 839
 840         u = cp->chars;
 841         while ((c = *u++) != '\0')
 842                 CHadd(cs, c);
 843         for (u = cp->multis; *u != '\0'; u += strlen(u) + 1)
 844                 MCadd(p, cs, u);
 845 }
 846
 847 /*
 848  - p_b_eclass - parse an equivalence-class name and deal with it
 849  == static void p_b_eclass(register struct parse *p, register cset *cs);
 850  *
 851  * This implementation is incomplete. xxx
 852  */
 853 static void
 854 p_b_eclass(p, cs)
 855 register struct parse *p;
 856 register cset *cs;
 857 {
 858         register char c;
 859
 860         c = p_b_coll_elem(p, '=');
 861         CHadd(cs, c);
 862 }
 863
 864 /*
 865  - p_b_symbol - parse a character or [..]ed multicharacter collating symbol
 866  == static char p_b_symbol(register struct parse *p);
 867  */
 868 static char                     /* value of symbol */
 869 p_b_symbol(p)
 870 register struct parse *p;
 871 {
 872         register char value;
 873
 874         REQUIRE(MORE(), REG_EBRACK);
 875         if (!EATTWO('[', '.'))
 876                 return(GETNEXT());
 877
 878         /* collating symbol */
 879         value = p_b_coll_elem(p, '.');
 880         REQUIRE(EATTWO('.', ']'), REG_ECOLLATE);
 881         return(value);
 882 }
 883
 884 /*
 885  - p_b_coll_elem - parse a collating-element name and look it up
 886  == static char p_b_coll_elem(register struct parse *p, int endc);
 887  */
 888 static char                     /* value of collating element */
 889 p_b_coll_elem(p, endc)
 890 register struct parse *p;
 891 int endc;                       /* name ended by endc,']' */
 892 {
 893         register RCHAR_T *sp = p->next;
 894         register struct cname *cp;
 895         register int len;
 896         register char c;
 897
 898         while (MORE() && !SEETWO(endc, ']'))
 899                 NEXT();
 900         if (!MORE()) {
 901                 SETERROR(REG_EBRACK);
 902                 return(0);
 903         }
 904         len = p->next - sp;
 905         for (cp = cnames; cp->name != NULL; cp++)
 906                 if (STRLEN(cp->name) == len && MEMCMP(cp->name, sp, len))
 907                         return(cp->code);       /* known name */
 908         if (len == 1)
 909                 return(*sp);    /* single character */
 910         SETERROR(REG_ECOLLATE);                 /* neither */
 911         return(0);
 912 }
 913
 914 /*
 915  - othercase - return the case counterpart of an alphabetic
 916  == static char othercase(int ch);
 917  */
 918 static char                     /* if no counterpart, return ch */
 919 othercase(ch)
 920 int ch;
 921 {
 922         assert(isalpha(ch));
 923         if (isupper(ch))
 924                 return(tolower(ch));
 925         else if (islower(ch))
 926                 return(toupper(ch));
 927         else                    /* peculiar, but could happen */
 928                 return(ch);
 929 }
 930
 931 /*
 932  - bothcases - emit a dualcase version of a two-case character
 933  == static void bothcases(register struct parse *p, int ch);
 934  *
 935  * Boy, is this implementation ever a kludge...
 936  */
 937 static void
 938 bothcases(p, ch)
 939 register struct parse *p;
 940 int ch;
 941 {
 942         register RCHAR_T *oldnext = p->next;
 943         register RCHAR_T *oldend = p->end;
 944         RCHAR_T bracket[3];
 945
 946         assert(othercase(ch) != ch);    /* p_bracket() would recurse */
 947         p->next = bracket;
 948         p->end = bracket+2;
 949         bracket[0] = ch;
 950         bracket[1] = ']';
 951         bracket[2] = '\0';
 952         p_bracket(p);
 953         assert(p->next == bracket+2);
 954         p->next = oldnext;
 955         p->end = oldend;
 956 }
 957
 958 /*
 959  - ordinary - emit an ordinary character
 960  == static void ordinary(register struct parse *p, register int ch);
 961  */
 962 static void
 963 ordinary(p, ch)
 964 register struct parse *p;
 965 register int ch;
 966 {
 967 /*
 968         register cat_t *cap = p->g->categories;
 969 */
 970
 971         if ((p->g->cflags&REG_ICASE) && isalpha(ch) && othercase(ch) != ch)
 972                 bothcases(p, ch);
 973         else {
 974                 EMIT(OCHAR, (UCHAR_T)ch);
 975 /*
 976                 if (cap[ch] == 0)
 977                         cap[ch] = p->g->ncategories++;
 978 */
 979         }
 980 }
 981
 982 /*
 983  - nonnewline - emit REG_NEWLINE version of OANY
 984  == static void nonnewline(register struct parse *p);
 985  *
 986  * Boy, is this implementation ever a kludge...
 987  */
 988 static void
 989 nonnewline(p)
 990 register struct parse *p;
 991 {
 992         register RCHAR_T *oldnext = p->next;
 993         register RCHAR_T *oldend = p->end;
 994         RCHAR_T bracket[4];
 995
 996         p->next = bracket;
 997         p->end = bracket+3;
 998         bracket[0] = '^';
 999         bracket[1] = '\n';
1000         bracket[2] = ']';
1001         bracket[3] = '\0';
1002         p_bracket(p);
1003         assert(p->next == bracket+3);
1004         p->next = oldnext;
1005         p->end = oldend;
1006 }
1007
1008 /*
1009  - repeat - generate code for a bounded repetition, recursively if needed
1010  == static void repeat(register struct parse *p, sopno start, int from, int to);
1011  */
1012 static void
1013 repeat(p, start, from, to)
1014 register struct parse *p;
1015 sopno start;                    /* operand from here to end of strip */
1016 int from;                       /* repeated from this number */
1017 int to;                         /* to this number of times (maybe INFINITY) */
1018 {
1019         register sopno finish = HERE();
1020 #       define  N       2
1021 #       define  INF     3
1022 #       define  REP(f, t)       ((f)*8 + (t))
1023 #       define  MAP(n)  (((n) <= 1) ? (n) : ((n) == INFINITY) ? INF : N)
1024         register sopno copy;
1025
1026         if (p->error != 0)      /* head off possible runaway recursion */
1027                 return;
1028
1029         assert(from <= to);
1030
1031         switch (REP(MAP(from), MAP(to))) {
1032         case REP(0, 0):                 /* must be user doing this */
1033                 DROP(finish-start);     /* drop the operand */
1034                 break;
1035         case REP(0, 1):                 /* as x{1,1}? */
1036         case REP(0, N):                 /* as x{1,n}? */
1037         case REP(0, INF):               /* as x{1,}? */
1038                 /* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
1039                 INSERT(OCH_, start);            /* offset is wrong... */
1040                 repeat(p, start+1, 1, to);
1041                 ASTERN(OOR1, start);
1042                 AHEAD(start);                   /* ... fix it */
1043                 EMIT(OOR2, 0);
1044                 AHEAD(THERE());
1045                 ASTERN(O_CH, THERETHERE());
1046                 break;
1047         case REP(1, 1):                 /* trivial case */
1048                 /* done */
1049                 break;
1050         case REP(1, N):                 /* as x?x{1,n-1} */
1051                 /* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
1052                 INSERT(OCH_, start);
1053                 ASTERN(OOR1, start);
1054                 AHEAD(start);
1055                 EMIT(OOR2, 0);                  /* offset very wrong... */
1056                 AHEAD(THERE());                 /* ...so fix it */
1057                 ASTERN(O_CH, THERETHERE());
1058                 copy = dupl(p, start+1, finish+1);
1059                 assert(copy == finish+4);
1060                 repeat(p, copy, 1, to-1);
1061                 break;
1062         case REP(1, INF):               /* as x+ */
1063                 INSERT(OPLUS_, start);
1064                 ASTERN(O_PLUS, start);
1065                 break;
1066         case REP(N, N):                 /* as xx{m-1,n-1} */
1067                 copy = dupl(p, start, finish);
1068                 repeat(p, copy, from-1, to-1);
1069                 break;
1070         case REP(N, INF):               /* as xx{n-1,INF} */
1071                 copy = dupl(p, start, finish);
1072                 repeat(p, copy, from-1, to);
1073                 break;
1074         default:                        /* "can't happen" */
1075                 SETERROR(REG_ASSERT);   /* just in case */
1076                 break;
1077         }
1078 }
1079
1080 /*
1081  - seterr - set an error condition
1082  == static int seterr(register struct parse *p, int e);
1083  */
1084 static int                      /* useless but makes type checking happy */
1085 seterr(p, e)
1086 register struct parse *p;
1087 int e;
1088 {
1089         if (p->error == 0)      /* keep earliest error condition */
1090                 p->error = e;
1091         p->next = nuls;         /* try to bring things to a halt */
1092         p->end = nuls;
1093         return(0);              /* make the return value well-defined */
1094 }
1095
1096 /*
1097  - allocset - allocate a set of characters for []
1098  == static cset *allocset(register struct parse *p);
1099  */
1100 static cset *
1101 allocset(p)
1102 register struct parse *p;
1103 {
1104         register int no = p->g->ncsets++;
1105         register size_t nc;
1106         register size_t nbytes;
1107         register cset *cs;
1108         register size_t css = (size_t)p->g->csetsize;
1109         register int i;
1110
1111         if (no >= p->ncsalloc) {        /* need another column of space */
1112                 p->ncsalloc += RCHAR_BIT;
1113                 nc = p->ncsalloc;
1114                 assert(nc % RCHAR_BIT == 0);
1115                 nbytes = nc / RCHAR_BIT * css;
1116                 if (p->g->sets == NULL)
1117                         p->g->sets = (cset *)malloc(nc * sizeof(cset));
1118                 else
1119                         p->g->sets = (cset *)realloc((char *)p->g->sets,
1120                                                         nc * sizeof(cset));
1121                 if (p->g->setbits == NULL)
1122                         p->g->setbits = (uch *)malloc(nbytes);
1123                 else {
1124                         p->g->setbits = (uch *)realloc((char *)p->g->setbits,
1125                                                                 nbytes);
1126                         /* xxx this isn't right if setbits is now NULL */
1127                         for (i = 0; i < no; i++)
1128                                 p->g->sets[i].ptr = p->g->setbits + css*(i/RCHAR_BIT);
1129                 }
1130                 if (p->g->sets != NULL && p->g->setbits != NULL)
1131                         (void) memset((char *)p->g->setbits + (nbytes - css),
1132                                                                 0, css);
1133                 else {
1134                         no = 0;
1135                         SETERROR(REG_ESPACE);
1136                         /* caller's responsibility not to do set ops */
1137                 }
1138         }
1139
1140         assert(p->g->sets != NULL);     /* xxx */
1141         cs = &p->g->sets[no];
1142         cs->ptr = p->g->setbits + css*((no)/RCHAR_BIT);
1143         cs->mask = 1 << ((no) % RCHAR_BIT);
1144         cs->hash = 0;
1145         cs->smultis = 0;
1146         cs->multis = NULL;
1147
1148         return(cs);
1149 }
1150
1151 /*
1152  - freeset - free a now-unused set
1153  == static void freeset(register struct parse *p, register cset *cs);
1154  */
1155 static void
1156 freeset(p, cs)
1157 register struct parse *p;
1158 register cset *cs;
1159 {
1160         register int i;
1161         register cset *top = &p->g->sets[p->g->ncsets];
1162         register size_t css = (size_t)p->g->csetsize;
1163
1164         for (i = 0; i < css; i++)
1165                 CHsub(cs, i);
1166         if (cs == top-1)        /* recover only the easy case */
1167                 p->g->ncsets--;
1168 }
1169
1170 /*
1171  - freezeset - final processing on a set of characters
1172  == static int freezeset(register struct parse *p, register cset *cs);
1173  *
1174  * The main task here is merging identical sets.  This is usually a waste
1175  * of time (although the hash code minimizes the overhead), but can win
1176  * big if REG_ICASE is being used.  REG_ICASE, by the way, is why the hash
1177  * is done using addition rather than xor -- all ASCII [aA] sets xor to
1178  * the same value!
1179  */
1180 static int                      /* set number */
1181 freezeset(p, cs)
1182 register struct parse *p;
1183 register cset *cs;
1184 {
1185         register uch h = cs->hash;
1186         register int i;
1187         register cset *top = &p->g->sets[p->g->ncsets];
1188         register cset *cs2;
1189         register size_t css = (size_t)p->g->csetsize;
1190
1191         /* look for an earlier one which is the same */
1192         for (cs2 = &p->g->sets[0]; cs2 < top; cs2++)
1193                 if (cs2->hash == h && cs2 != cs) {
1194                         /* maybe */
1195                         for (i = 0; i < css; i++)
1196                                 if (!!CHIN(cs2, i) != !!CHIN(cs, i))
1197                                         break;          /* no */
1198                         if (i == css)
1199                                 break;                  /* yes */
1200                 }
1201
1202         if (cs2 < top) {        /* found one */
1203                 freeset(p, cs);
1204                 cs = cs2;
1205         }
1206
1207         return((int)(cs - p->g->sets));
1208 }
1209
1210 /*
1211  - firstch - return first character in a set (which must have at least one)
1212  == static int firstch(register struct parse *p, register cset *cs);
1213  */
1214 static int                      /* character; there is no "none" value */
1215 firstch(p, cs)
1216 register struct parse *p;
1217 register cset *cs;
1218 {
1219         register int i;
1220         register size_t css = (size_t)p->g->csetsize;
1221
1222         for (i = 0; i < css; i++)
1223                 if (CHIN(cs, i))
1224                         return((char)i);
1225         assert(never);
1226         return(0);              /* arbitrary */
1227 }
1228
1229 /*
1230  - nch - number of characters in a set
1231  == static int nch(register struct parse *p, register cset *cs);
1232  */
1233 static int
1234 nch(p, cs)
1235 register struct parse *p;
1236 register cset *cs;
1237 {
1238         register int i;
1239         register size_t css = (size_t)p->g->csetsize;
1240         register int n = 0;
1241
1242         for (i = 0; i < css; i++)
1243                 if (CHIN(cs, i))
1244                         n++;
1245         return(n);
1246 }
1247
1248 /*
1249  - mcadd - add a collating element to a cset
1250  == static void mcadd(register struct parse *p, register cset *cs, \
1251  ==     register char *cp);
1252  */
1253 static void
1254 mcadd(p, cs, cp)
1255 register struct parse *p;
1256 register cset *cs;
1257 register char *cp;
1258 {
1259         register size_t oldend = cs->smultis;
1260
1261         cs->smultis += strlen(cp) + 1;
1262         if (cs->multis == NULL)
1263                 cs->multis = malloc(cs->smultis);
1264         else
1265                 cs->multis = realloc(cs->multis, cs->smultis);
1266         if (cs->multis == NULL) {
1267                 SETERROR(REG_ESPACE);
1268                 return;
1269         }
1270
1271         (void) strcpy(cs->multis + oldend - 1, cp);
1272         cs->multis[cs->smultis - 1] = '\0';
1273 }
1274
1275 /*
1276  - mcsub - subtract a collating element from a cset
1277  == static void mcsub(register cset *cs, register char *cp);
1278  */
1279 static void
1280 mcsub(cs, cp)
1281 register cset *cs;
1282 register char *cp;
1283 {
1284         register char *fp = mcfind(cs, cp);
1285         register size_t len = strlen(fp);
1286
1287         assert(fp != NULL);
1288         (void) memmove(fp, fp + len + 1,
1289                                 cs->smultis - (fp + len + 1 - cs->multis));
1290         cs->smultis -= len;
1291
1292         if (cs->smultis == 0) {
1293                 free(cs->multis);
1294                 cs->multis = NULL;
1295                 return;
1296         }
1297
1298         cs->multis = realloc(cs->multis, cs->smultis);
1299         assert(cs->multis != NULL);
1300 }
1301
1302 /*
1303  - mcin - is a collating element in a cset?
1304  == static int mcin(register cset *cs, register char *cp);
1305  */
1306 static int
1307 mcin(cs, cp)
1308 register cset *cs;
1309 register char *cp;
1310 {
1311         return(mcfind(cs, cp) != NULL);
1312 }
1313
1314 /*
1315  - mcfind - find a collating element in a cset
1316  == static char *mcfind(register cset *cs, register char *cp);
1317  */
1318 static char *
1319 mcfind(cs, cp)
1320 register cset *cs;
1321 register char *cp;
1322 {
1323         register char *p;
1324
1325         if (cs->multis == NULL)
1326                 return(NULL);
1327         for (p = cs->multis; *p != '\0'; p += strlen(p) + 1)
1328                 if (strcmp(cp, p) == 0)
1329                         return(p);
1330         return(NULL);
1331 }
1332
1333 /*
1334  - mcinvert - invert the list of collating elements in a cset
1335  == static void mcinvert(register struct parse *p, register cset *cs);
1336  *
1337  * This would have to know the set of possibilities.  Implementation
1338  * is deferred.
1339  */
1340 static void
1341 mcinvert(p, cs)
1342 register struct parse *p;
1343 register cset *cs;
1344 {
1345         assert(cs->multis == NULL);     /* xxx */
1346 }
1347
1348 /*
1349  - mccase - add case counterparts of the list of collating elements in a cset
1350  == static void mccase(register struct parse *p, register cset *cs);
1351  *
1352  * This would have to know the set of possibilities.  Implementation
1353  * is deferred.
1354  */
1355 static void
1356 mccase(p, cs)
1357 register struct parse *p;
1358 register cset *cs;
1359 {
1360         assert(cs->multis == NULL);     /* xxx */
1361 }
1362
1363 /*
1364  - isinsets - is this character in any sets?
1365  == static int isinsets(register struct re_guts *g, int c);
1366  */
1367 static int                      /* predicate */
1368 isinsets(g, c)
1369 register struct re_guts *g;
1370 int c;
1371 {
1372         register uch *col;
1373         register int i;
1374         register int ncols = (g->ncsets+(RCHAR_BIT-1)) / RCHAR_BIT;
1375         register unsigned uc = (unsigned char)c;
1376
1377         for (i = 0, col = g->setbits; i < ncols; i++, col += g->csetsize)
1378                 if (col[uc] != 0)
1379                         return(1);
1380         return(0);
1381 }
1382
1383 /*
1384  - samesets - are these two characters in exactly the same sets?
1385  == static int samesets(register struct re_guts *g, int c1, int c2);
1386  */
1387 static int                      /* predicate */
1388 samesets(g, c1, c2)
1389 register struct re_guts *g;
1390 int c1;
1391 int c2;
1392 {
1393         register uch *col;
1394         register int i;
1395         register int ncols = (g->ncsets+(RCHAR_BIT-1)) / RCHAR_BIT;
1396         register unsigned uc1 = (unsigned char)c1;
1397         register unsigned uc2 = (unsigned char)c2;
1398
1399         for (i = 0, col = g->setbits; i < ncols; i++, col += g->csetsize)
1400                 if (col[uc1] != col[uc2])
1401                         return(0);
1402         return(1);
1403 }
1404
1405 /*
1406  - categorize - sort out character categories
1407  == static void categorize(struct parse *p, register struct re_guts *g);
1408  */
1409 static void
1410 categorize(p, g)
1411 struct parse *p;
1412 register struct re_guts *g;
1413 {
1414 /*
1415         register cat_t *cats = g->categories;
1416 */
1417         register int c;
1418         register int c2;
1419         register cat_t cat;
1420
1421         /* avoid making error situations worse */
1422         if (p->error != 0)
1423                 return;
1424
1425 /*
1426         for (c = CHAR_MIN; c <= CHAR_MAX; c++)
1427                 if (cats[c] == 0 && isinsets(g, c)) {
1428                         cat = g->ncategories++;
1429                         cats[c] = cat;
1430                         for (c2 = c+1; c2 <= CHAR_MAX; c2++)
1431                                 if (cats[c2] == 0 && samesets(g, c, c2))
1432                                         cats[c2] = cat;
1433                 }
1434 */
1435 }
1436
1437 /*
1438  - dupl - emit a duplicate of a bunch of sops
1439  == static sopno dupl(register struct parse *p, sopno start, sopno finish);
1440  */
1441 static sopno                    /* start of duplicate */
1442 dupl(p, start, finish)
1443 register struct parse *p;
1444 sopno start;                    /* from here */
1445 sopno finish;                   /* to this less one */
1446 {
1447         register sopno ret = HERE();
1448         register sopno len = finish - start;
1449
1450         assert(finish >= start);
1451         if (len == 0)
1452                 return(ret);
1453         enlarge(p, p->ssize + len);     /* this many unexpected additions */
1454         assert(p->ssize >= p->slen + len);
1455         (void) memcpy((char *)(p->strip + p->slen),
1456                 (char *)(p->strip + start), (size_t)len*sizeof(sop));
1457         p->slen += len;
1458         return(ret);
1459 }
1460
1461 /*
1462  - doemit - emit a strip operator
1463  == static void doemit(register struct parse *p, sop op, size_t opnd);
1464  *
1465  * It might seem better to implement this as a macro with a function as
1466  * hard-case backup, but it's just too big and messy unless there are
1467  * some changes to the data structures.  Maybe later.
1468  */
1469 static void
1470 doemit(p, op, opnd)
1471 register struct parse *p;
1472 sop op;
1473 size_t opnd;
1474 {
1475         /* avoid making error situations worse */
1476         if (p->error != 0)
1477                 return;
1478
1479         /* deal with oversize operands ("can't happen", more or less) */
1480         assert(opnd < 1<<OPSHIFT);
1481
1482         /* deal with undersized strip */
1483         if (p->slen >= p->ssize)
1484                 enlarge(p, (p->ssize+1) / 2 * 3);       /* +50% */
1485         assert(p->slen < p->ssize);
1486
1487         /* finally, it's all reduced to the easy case */
1488         p->strip[p->slen++] = SOP(op, opnd);
1489 }
1490
1491 /*
1492  - doinsert - insert a sop into the strip
1493  == static void doinsert(register struct parse *p, sop op, size_t opnd, sopno pos);
1494  */
1495 static void
1496 doinsert(p, op, opnd, pos)
1497 register struct parse *p;
1498 sop op;
1499 size_t opnd;
1500 sopno pos;
1501 {
1502         register sopno sn;
1503         register sop s;
1504         register int i;
1505
1506         /* avoid making error situations worse */
1507         if (p->error != 0)
1508                 return;
1509
1510         sn = HERE();
1511         EMIT(op, opnd);         /* do checks, ensure space */
1512         assert(HERE() == sn+1);
1513         s = p->strip[sn];
1514
1515         /* adjust paren pointers */
1516         assert(pos > 0);
1517         for (i = 1; i < NPAREN; i++) {
1518                 if (p->pbegin[i] >= pos) {
1519                         p->pbegin[i]++;
1520                 }
1521                 if (p->pend[i] >= pos) {
1522                         p->pend[i]++;
1523                 }
1524         }
1525
1526         memmove((char *)&p->strip[pos+1], (char *)&p->strip[pos],
1527                                                 (HERE()-pos-1)*sizeof(sop));
1528         p->strip[pos] = s;
1529 }
1530
1531 /*
1532  - dofwd - complete a forward reference
1533  == static void dofwd(register struct parse *p, sopno pos, sop value);
1534  */
1535 static void
1536 dofwd(p, pos, value)
1537 register struct parse *p;
1538 register sopno pos;
1539 sop value;
1540 {
1541         /* avoid making error situations worse */
1542         if (p->error != 0)
1543                 return;
1544
1545         assert(value < 1<<OPSHIFT);
1546         p->strip[pos] = OP(p->strip[pos]) | value;
1547 }
1548
1549 /*
1550  - enlarge - enlarge the strip
1551  == static void enlarge(register struct parse *p, sopno size);
1552  */
1553 static void
1554 enlarge(p, size)
1555 register struct parse *p;
1556 register sopno size;
1557 {
1558         register sop *sp;
1559
1560         if (p->ssize >= size)
1561                 return;
1562
1563         sp = (sop *)realloc(p->strip, size*sizeof(sop));
1564         if (sp == NULL) {
1565                 SETERROR(REG_ESPACE);
1566                 return;
1567         }
1568         p->strip = sp;
1569         p->ssize = size;
1570 }
1571
1572 /*
1573  - stripsnug - compact the strip
1574  == static void stripsnug(register struct parse *p, register struct re_guts *g);
1575  */
1576 static void
1577 stripsnug(p, g)
1578 register struct parse *p;
1579 register struct re_guts *g;
1580 {
1581         g->nstates = p->slen;
1582         g->strip = (sop *)realloc((char *)p->strip, p->slen * sizeof(sop));
1583         if (g->strip == NULL) {
1584                 SETERROR(REG_ESPACE);
1585                 g->strip = p->strip;
1586         }
1587 }
1588
1589 /*
1590  - findmust - fill in must and mlen with longest mandatory literal string
1591  == static void findmust(register struct parse *p, register struct re_guts *g);
1592  *
1593  * This algorithm could do fancy things like analyzing the operands of |
1594  * for common subsequences.  Someday.  This code is simple and finds most
1595  * of the interesting cases.
1596  *
1597  * Note that must and mlen got initialized during setup.
1598  */
1599 static void
1600 findmust(p, g)
1601 struct parse *p;
1602 register struct re_guts *g;
1603 {
1604         register sop *scan;
1605         sop *start;
1606         register sop *newstart;
1607         register sopno newlen;
1608         register sop s;
1609         register RCHAR_T *cp;
1610         register sopno i;
1611
1612         /* avoid making error situations worse */
1613         if (p->error != 0)
1614                 return;
1615
1616         /* find the longest OCHAR sequence in strip */
1617         newlen = 0;
1618         scan = g->strip + 1;
1619         do {
1620                 s = *scan++;
1621                 switch (OP(s)) {
1622                 case OCHAR:             /* sequence member */
1623                         if (newlen == 0)                /* new sequence */
1624                                 newstart = scan - 1;
1625                         newlen++;
1626                         break;
1627                 case OPLUS_:            /* things that don't break one */
1628                 case OLPAREN:
1629                 case ORPAREN:
1630                         break;
1631                 case OQUEST_:           /* things that must be skipped */
1632                 case OCH_:
1633                         scan--;
1634                         do {
1635                                 scan += OPND(s);
1636                                 s = *scan;
1637                                 /* assert() interferes w debug printouts */
1638                                 if (OP(s) != O_QUEST && OP(s) != O_CH &&
1639                                                         OP(s) != OOR2) {
1640                                         g->iflags |= BAD;
1641                                         return;
1642                                 }
1643                         } while (OP(s) != O_QUEST && OP(s) != O_CH);
1644                         /* fallthrough */
1645                 default:                /* things that break a sequence */
1646                         if (newlen > g->mlen) {         /* ends one */
1647                                 start = newstart;
1648                                 g->mlen = newlen;
1649                         }
1650                         newlen = 0;
1651                         break;
1652                 }
1653         } while (OP(s) != OEND);
1654
1655         if (g->mlen == 0)               /* there isn't one */
1656                 return;
1657
1658         /* turn it into a character string */
1659         g->must = malloc(((size_t)g->mlen + 1) * sizeof(RCHAR_T));
1660         if (g->must == NULL) {          /* argh; just forget it */
1661                 g->mlen = 0;
1662                 return;
1663         }
1664         cp = g->must;
1665         scan = start;
1666         for (i = g->mlen; i > 0; i--) {
1667                 while (OP(s = *scan++) != OCHAR)
1668                         continue;
1669                 assert(cp < g->must + g->mlen);
1670                 *cp++ = (RCHAR_T)OPND(s);
1671         }
1672         assert(cp == g->must + g->mlen);
1673         *cp++ = '\0';           /* just on general principles */
1674 }
1675
1676 /*
1677  - pluscount - count + nesting
1678  == static sopno pluscount(register struct parse *p, register struct re_guts *g);
1679  */
1680 static sopno                    /* nesting depth */
1681 pluscount(p, g)
1682 struct parse *p;
1683 register struct re_guts *g;
1684 {
1685         register sop *scan;
1686         register sop s;
1687         register sopno plusnest = 0;
1688         register sopno maxnest = 0;
1689
1690         if (p->error != 0)
1691                 return(0);      /* there may not be an OEND */
1692
1693         scan = g->strip + 1;
1694         do {
1695                 s = *scan++;
1696                 switch (OP(s)) {
1697                 case OPLUS_:
1698                         plusnest++;
1699                         break;
1700                 case O_PLUS:
1701                         if (plusnest > maxnest)
1702                                 maxnest = plusnest;
1703                         plusnest--;
1704                         break;
1705                 }
1706         } while (OP(s) != OEND);
1707         if (plusnest != 0)
1708                 g->iflags |= BAD;
1709         return(maxnest);
1710 }