engine.c revision 1.26
1 /* $NetBSD: engine.c,v 1.26 2021/02/24 09:10:12 wiz Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-3-Clause 5 * 6 * Copyright (c) 1992, 1993, 1994 Henry Spencer. 7 * Copyright (c) 1992, 1993, 1994 8 * The Regents of the University of California. All rights reserved. 9 * 10 * This code is derived from software contributed to Berkeley by 11 * Henry Spencer. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. 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 * @(#)engine.c 8.5 (Berkeley) 3/20/94 38 */ 39 40 #include <sys/cdefs.h> 41 #ifdef __FBSDID 42 __FBSDID("$FreeBSD: head/lib/libc/regex/engine.c 368358 2020-12-05 03:16:05Z kevans $"); 43 #endif 44 __RCSID("$NetBSD: engine.c,v 1.26 2021/02/24 09:10:12 wiz Exp $"); 45 46 #include <stdbool.h> 47 48 /* 49 * The matching engine and friends. This file is #included by regexec.c 50 * after suitable #defines of a variety of macros used herein, so that 51 * different state representations can be used without duplicating masses 52 * of code. 53 */ 54 55 #ifdef SNAMES 56 #define stepback sstepback 57 #define matcher smatcher 58 #define walk swalk 59 #define dissect sdissect 60 #define backref sbackref 61 #define step sstep 62 #define print sprint 63 #define at sat 64 #define match smat 65 #endif 66 #ifdef LNAMES 67 #define stepback lstepback 68 #define matcher lmatcher 69 #define walk lwalk 70 #define dissect ldissect 71 #define backref lbackref 72 #define step lstep 73 #define print lprint 74 #define at lat 75 #define match lmat 76 #endif 77 #ifdef MNAMES 78 #define stepback mstepback 79 #define matcher mmatcher 80 #define walk mwalk 81 #define dissect mdissect 82 #define backref mbackref 83 #define step mstep 84 #define print mprint 85 #define at mat 86 #define match mmat 87 #endif 88 89 /* another structure passed up and down to avoid zillions of parameters */ 90 struct match { 91 struct re_guts *g; 92 int eflags; 93 regmatch_t *pmatch; /* [nsub+1] (0 element unused) */ 94 const char *offp; /* offsets work from here */ 95 const char *beginp; /* start of string -- virtual NUL precedes */ 96 const char *endp; /* end of string -- virtual NUL here */ 97 const char *coldp; /* can be no match starting before here */ 98 const char **lastpos; /* [nplus+1] */ 99 STATEVARS; 100 states st; /* current states */ 101 states fresh; /* states for a fresh start */ 102 states tmp; /* temporary */ 103 states empty; /* empty set of states */ 104 mbstate_t mbs; /* multibyte conversion state */ 105 }; 106 107 /* ========= begin header generated by ./mkh ========= */ 108 #ifdef __cplusplus 109 extern "C" { 110 #endif 111 112 /* === engine.c === */ 113 static int matcher(struct re_guts *g, const char *string, size_t nmatch, regmatch_t pmatch[], int eflags); 114 static const char *dissect(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst); 115 static const char *backref(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst, sopno lev, int); 116 static const char *walk(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst, bool fast); 117 static states step(struct re_guts *g, sopno start, sopno stop, states bef, wint_t ch, states aft, int sflags); 118 #define MAX_RECURSION 100 119 #define BOL (OUT-1) 120 #define EOL (BOL-1) 121 #define BOLEOL (BOL-2) 122 #define NOTHING (BOL-3) 123 #define BOW (BOL-4) 124 #define EOW (BOL-5) 125 #define BADCHAR (BOL-6) 126 #define NWBND (BOL-7) 127 #define NONCHAR(c) ((c) <= OUT) 128 /* sflags */ 129 #define SBOS 0x0001 130 #define SEOS 0x0002 131 132 #ifdef REDEBUG 133 static void print(struct match *m, const char *caption, states st, int ch, FILE *d); 134 #endif 135 #ifdef REDEBUG 136 static void at(struct match *m, const char *title, const char *start, const char *stop, sopno startst, sopno stopst); 137 #endif 138 #ifdef REDEBUG 139 static const char *pchar(int ch); 140 #endif 141 142 #ifdef __cplusplus 143 } 144 #endif 145 /* ========= end header generated by ./mkh ========= */ 146 147 #ifdef REDEBUG 148 #define SP(t, s, c) print(m, t, s, c, stdout) 149 #define AT(t, p1, p2, s1, s2) at(m, t, p1, p2, s1, s2) 150 #define NOTE(str) { if (m->eflags®_TRACE) printf("=%s\n", (str)); } 151 #else 152 #define SP(t, s, c) /* nothing */ 153 #define AT(t, p1, p2, s1, s2) /* nothing */ 154 #define NOTE(s) /* nothing */ 155 #endif 156 157 /* 158 * Given a multibyte string pointed to by start, step back nchar characters 159 * from current position pointed to by cur. 160 */ 161 static const char * 162 stepback(const char *start, const char *cur, int nchar) 163 { 164 const char *ret; 165 size_t wc, mbc; 166 mbstate_t mbs; 167 size_t clen; 168 169 if (MB_CUR_MAX == 1) 170 return ((cur - nchar) > start ? cur - nchar : NULL); 171 172 ret = cur; 173 for (wc = nchar; wc > 0; wc--) { 174 for (mbc = 1; mbc <= MB_CUR_MAX; mbc++) { 175 if ((ret - mbc) < start) 176 return (NULL); 177 memset(&mbs, 0, sizeof(mbs)); 178 clen = mbrtowc(NULL, ret - mbc, mbc, &mbs); 179 if (clen != (size_t)-1 && clen != (size_t)-2) 180 break; 181 } 182 if (mbc > MB_CUR_MAX) 183 return (NULL); 184 ret -= mbc; 185 } 186 187 return (ret); 188 } 189 190 /* 191 - matcher - the actual matching engine 192 == static int matcher(struct re_guts *g, const char *string, \ 193 == size_t nmatch, regmatch_t pmatch[], int eflags); 194 */ 195 static int /* 0 success, REG_NOMATCH failure */ 196 matcher(struct re_guts *g, 197 const char *string, 198 size_t nmatch, 199 regmatch_t pmatch[], 200 int eflags) 201 { 202 const char *endp; 203 size_t i; 204 struct match mv; 205 struct match *m = &mv; 206 const char *dp = NULL; 207 const sopno gf = g->firststate+1; /* +1 for OEND */ 208 const sopno gl = g->laststate; 209 const char *start; 210 const char *stop; 211 /* Boyer-Moore algorithms variables */ 212 const char *pp; 213 int cj, mj; 214 const char *mustfirst; 215 const char *mustlast; 216 size_t *matchjump; 217 size_t *charjump; 218 int error = 0; 219 220 _DIAGASSERT(g != NULL); 221 _DIAGASSERT(string != NULL); 222 /* pmatch checked below */ 223 224 /* simplify the situation where possible */ 225 if (g->cflags®_NOSUB) 226 nmatch = 0; 227 if (eflags®_STARTEND) { 228 _DIAGASSERT(pmatch != NULL); 229 start = string + (size_t)pmatch[0].rm_so; 230 stop = string + (size_t)pmatch[0].rm_eo; 231 } else { 232 start = string; 233 stop = start + strlen(start); 234 } 235 if (stop < start) 236 return(REG_INVARG); 237 238 /* prescreening; this does wonders for this rather slow code */ 239 if (g->must != NULL) { 240 if (g->charjump != NULL && g->matchjump != NULL) { 241 mustfirst = g->must; 242 mustlast = g->must + g->mlen - 1; 243 charjump = g->charjump; 244 matchjump = g->matchjump; 245 pp = mustlast; 246 for (dp = start+g->mlen-1; dp < stop;) { 247 /* Fast skip non-matches */ 248 while (dp < stop && charjump[(int)*dp]) 249 dp += charjump[(int)*dp]; 250 251 if (dp >= stop) 252 break; 253 254 /* Greedy matcher */ 255 /* We depend on not being used for 256 * for strings of length 1 257 */ 258 while (*--dp == *--pp && pp != mustfirst); 259 260 if (*dp == *pp) 261 break; 262 263 /* Jump to next possible match */ 264 mj = matchjump[pp - mustfirst]; 265 cj = charjump[(int)*dp]; 266 dp += (cj < mj ? mj : cj); 267 pp = mustlast; 268 } 269 if (pp != mustfirst) 270 return(REG_NOMATCH); 271 } else { 272 for (dp = start; dp < stop; dp++) 273 if (*dp == g->must[0] && 274 (size_t)(stop - dp) >= g->mlen && 275 memcmp(dp, g->must, (size_t)g->mlen) == 0) 276 break; 277 if (dp == stop) /* we didn't find g->must */ 278 return(REG_NOMATCH); 279 } 280 } 281 282 /* match struct setup */ 283 m->g = g; 284 m->eflags = eflags; 285 m->pmatch = NULL; 286 m->lastpos = NULL; 287 m->offp = string; 288 m->beginp = start; 289 m->endp = stop; 290 STATESETUP(m, 4); 291 SETUP(m->st); 292 SETUP(m->fresh); 293 SETUP(m->tmp); 294 SETUP(m->empty); 295 CLEAR(m->empty); 296 ZAPSTATE(&m->mbs); 297 298 /* Adjust start according to moffset, to speed things up */ 299 if (dp != NULL && g->moffset > -1) { 300 const char *nstart; 301 302 nstart = stepback(start, dp, g->moffset); 303 if (nstart != NULL) 304 start = nstart; 305 } 306 307 SP("mloop", m->st, *start); 308 309 /* this loop does only one repetition except for backrefs */ 310 for (;;) { 311 endp = walk(m, start, stop, gf, gl, true); 312 if (endp == NULL) { /* a miss */ 313 error = REG_NOMATCH; 314 goto done; 315 } 316 if (nmatch == 0 && !g->backrefs) 317 break; /* no further info needed */ 318 319 /* where? */ 320 assert(m->coldp != NULL); 321 for (;;) { 322 NOTE("finding start"); 323 endp = walk(m, m->coldp, stop, gf, gl, false); 324 if (endp != NULL) 325 break; 326 assert(m->coldp < m->endp); 327 m->coldp += XMBRTOWC(NULL, m->coldp, 328 m->endp - m->coldp, &m->mbs, 0); 329 } 330 if (nmatch == 1 && !g->backrefs) 331 break; /* no further info needed */ 332 333 /* oh my, he wants the subexpressions... */ 334 if (m->pmatch == NULL) 335 m->pmatch = (regmatch_t *)malloc((m->g->nsub + 1) * 336 sizeof(regmatch_t)); 337 if (m->pmatch == NULL) { 338 error = REG_ESPACE; 339 goto done; 340 } 341 for (i = 1; i <= m->g->nsub; i++) 342 m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1; 343 if (!g->backrefs && !(m->eflags®_BACKR)) { 344 NOTE("dissecting"); 345 dp = dissect(m, m->coldp, endp, gf, gl); 346 } else { 347 if (g->nplus > 0 && m->lastpos == NULL) 348 m->lastpos = malloc((g->nplus+1) * 349 sizeof(const char *)); 350 if (g->nplus > 0 && m->lastpos == NULL) { 351 error = REG_ESPACE; 352 goto done; 353 } 354 NOTE("backref dissect"); 355 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0); 356 } 357 if (dp != NULL) 358 break; 359 360 /* uh-oh... we couldn't find a subexpression-level match */ 361 assert(g->backrefs); /* must be back references doing it */ 362 assert(g->nplus == 0 || m->lastpos != NULL); 363 for (;;) { 364 if (dp != NULL || endp <= m->coldp) 365 break; /* defeat */ 366 NOTE("backoff"); 367 endp = walk(m, m->coldp, endp-1, gf, gl, false); 368 if (endp == NULL) 369 break; /* defeat */ 370 /* try it on a shorter possibility */ 371 #ifndef NDEBUG 372 for (i = 1; i <= m->g->nsub; i++) { 373 assert(m->pmatch[i].rm_so == (regoff_t)-1); 374 assert(m->pmatch[i].rm_eo == (regoff_t)-1); 375 } 376 #endif 377 NOTE("backoff dissect"); 378 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0); 379 } 380 assert(dp == NULL || dp == endp); 381 if (dp != NULL) /* found a shorter one */ 382 break; 383 384 /* despite initial appearances, there is no match here */ 385 NOTE("false alarm"); 386 /* recycle starting later */ 387 start = m->coldp + XMBRTOWC(NULL, m->coldp, 388 stop - m->coldp, &m->mbs, 0); 389 assert(start <= stop); 390 } 391 392 /* fill in the details if requested */ 393 if (nmatch > 0) { 394 _DIAGASSERT(pmatch != NULL); 395 pmatch[0].rm_so = m->coldp - m->offp; 396 pmatch[0].rm_eo = endp - m->offp; 397 } 398 if (nmatch > 1) { 399 assert(m->pmatch != NULL); 400 for (i = 1; i < nmatch; i++) 401 if (i <= m->g->nsub) 402 pmatch[i] = m->pmatch[i]; 403 else { 404 pmatch[i].rm_so = (regoff_t)-1; 405 pmatch[i].rm_eo = (regoff_t)-1; 406 } 407 } 408 409 done: 410 if (m->pmatch != NULL) { 411 free(m->pmatch); 412 m->pmatch = NULL; 413 } 414 if (m->lastpos != NULL) { 415 free((char *)m->lastpos); 416 m->lastpos = NULL; 417 } 418 STATETEARDOWN(m); 419 return error; 420 } 421 422 /* 423 - dissect - figure out what matched what, no back references 424 == static const char *dissect(struct match *m, const char *start, \ 425 == const char *stop, sopno startst, sopno stopst); 426 */ 427 static const char * /* == stop (success) always */ 428 dissect( 429 struct match *m, 430 const char *start, 431 const char *stop, 432 sopno startst, 433 sopno stopst) 434 { 435 int i; 436 sopno ss; /* start sop of current subRE */ 437 sopno es; /* end sop of current subRE */ 438 const char *sp; /* start of string matched by it */ 439 const char *stp; /* string matched by it cannot pass here */ 440 const char *rest; /* start of rest of string */ 441 const char *tail; /* string unmatched by rest of RE */ 442 sopno ssub; /* start sop of subsubRE */ 443 sopno esub; /* end sop of subsubRE */ 444 const char *ssp; /* start of string matched by subsubRE */ 445 const char *sep; /* end of string matched by subsubRE */ 446 const char *oldssp; /* previous ssp */ 447 const char *dp __unused; 448 449 _DIAGASSERT(m != NULL); 450 _DIAGASSERT(start != NULL); 451 _DIAGASSERT(stop != NULL); 452 453 AT("diss", start, stop, startst, stopst); 454 sp = start; 455 for (ss = startst; ss < stopst; ss = es) { 456 /* identify end of subRE */ 457 es = ss; 458 switch (OP(m->g->strip[es])) { 459 case OPLUS_: 460 case OQUEST_: 461 es += OPND(m->g->strip[es]); 462 break; 463 case OCH_: 464 while (OP(m->g->strip[es]) != (sop)O_CH) 465 es += OPND(m->g->strip[es]); 466 break; 467 } 468 es++; 469 470 /* figure out what it matched */ 471 switch (OP(m->g->strip[ss])) { 472 case OEND: 473 assert(nope); 474 break; 475 case OCHAR: 476 sp += XMBRTOWC(NULL, sp, stop - start, &m->mbs, 0); 477 break; 478 case OBOL: 479 case OEOL: 480 case OBOW: 481 case OEOW: 482 case OBOS: 483 case OEOS: 484 case OWBND: 485 case ONWBND: 486 break; 487 case OANY: 488 case OANYOF: 489 sp += XMBRTOWC(NULL, sp, stop - start, &m->mbs, 0); 490 break; 491 case OBACK_: 492 case O_BACK: 493 assert(nope); 494 break; 495 /* cases where length of match is hard to find */ 496 case OQUEST_: 497 stp = stop; 498 for (;;) { 499 /* how long could this one be? */ 500 rest = walk(m, sp, stp, ss, es, false); 501 assert(rest != NULL); /* it did match */ 502 /* could the rest match the rest? */ 503 tail = walk(m, rest, stop, es, stopst, false); 504 if (tail == stop) 505 break; /* yes! */ 506 /* no -- try a shorter match for this one */ 507 stp = rest - 1; 508 assert(stp >= sp); /* it did work */ 509 } 510 ssub = ss + 1; 511 esub = es - 1; 512 /* did innards match? */ 513 if (walk(m, sp, rest, ssub, esub, false) != NULL) { 514 dp = dissect(m, sp, rest, ssub, esub); 515 assert(dp == rest); 516 } else /* no */ 517 assert(sp == rest); 518 sp = rest; 519 break; 520 case OPLUS_: 521 stp = stop; 522 for (;;) { 523 /* how long could this one be? */ 524 rest = walk(m, sp, stp, ss, es, false); 525 assert(rest != NULL); /* it did match */ 526 /* could the rest match the rest? */ 527 tail = walk(m, rest, stop, es, stopst, false); 528 if (tail == stop) 529 break; /* yes! */ 530 /* no -- try a shorter match for this one */ 531 stp = rest - 1; 532 assert(stp >= sp); /* it did work */ 533 } 534 ssub = ss + 1; 535 esub = es - 1; 536 ssp = sp; 537 oldssp = ssp; 538 for (;;) { /* find last match of innards */ 539 sep = walk(m, ssp, rest, ssub, esub, false); 540 if (sep == NULL || sep == ssp) 541 break; /* failed or matched null */ 542 oldssp = ssp; /* on to next try */ 543 ssp = sep; 544 } 545 if (sep == NULL) { 546 /* last successful match */ 547 sep = ssp; 548 ssp = oldssp; 549 } 550 assert(sep == rest); /* must exhaust substring */ 551 assert(walk(m, ssp, sep, ssub, esub, false) == rest); 552 dp = dissect(m, ssp, sep, ssub, esub); 553 assert(dp == sep); 554 sp = rest; 555 break; 556 case OCH_: 557 stp = stop; 558 for (;;) { 559 /* how long could this one be? */ 560 rest = walk(m, sp, stp, ss, es, false); 561 assert(rest != NULL); /* it did match */ 562 /* could the rest match the rest? */ 563 tail = walk(m, rest, stop, es, stopst, false); 564 if (tail == stop) 565 break; /* yes! */ 566 /* no -- try a shorter match for this one */ 567 stp = rest - 1; 568 assert(stp >= sp); /* it did work */ 569 } 570 ssub = ss + 1; 571 esub = ss + OPND(m->g->strip[ss]) - 1; 572 assert(OP(m->g->strip[esub]) == OOR1); 573 for (;;) { /* find first matching branch */ 574 if (walk(m, sp, rest, ssub, esub, false) == rest) 575 break; /* it matched all of it */ 576 /* that one missed, try next one */ 577 assert(OP(m->g->strip[esub]) == OOR1); 578 esub++; 579 assert(OP(m->g->strip[esub]) == OOR2); 580 ssub = esub + 1; 581 esub += OPND(m->g->strip[esub]); 582 if (OP(m->g->strip[esub]) == (sop)OOR2) 583 esub--; 584 else 585 assert(OP(m->g->strip[esub]) == O_CH); 586 } 587 dp = dissect(m, sp, rest, ssub, esub); 588 assert(dp == rest); 589 sp = rest; 590 break; 591 case O_PLUS: 592 case O_QUEST: 593 case OOR1: 594 case OOR2: 595 case O_CH: 596 assert(nope); 597 break; 598 case OLPAREN: 599 i = OPND(m->g->strip[ss]); 600 assert(0 < i && i <= m->g->nsub); 601 m->pmatch[i].rm_so = sp - m->offp; 602 break; 603 case ORPAREN: 604 i = OPND(m->g->strip[ss]); 605 assert(0 < i && i <= m->g->nsub); 606 m->pmatch[i].rm_eo = sp - m->offp; 607 break; 608 default: /* uh oh */ 609 assert(nope); 610 break; 611 } 612 } 613 614 assert(sp == stop); 615 return(sp); 616 } 617 618 #define ISBOW(m, sp) \ 619 (sp < m->endp && ISWORD(*sp) && \ 620 ((sp == m->beginp && !(m->eflags®_NOTBOL)) || \ 621 (sp > m->offp && !ISWORD(*(sp-1))))) 622 #define ISEOW(m, sp) \ 623 (((sp == m->endp && !(m->eflags®_NOTEOL)) || \ 624 (sp < m->endp && *sp == '\n' && \ 625 (m->g->cflags®_NEWLINE)) || \ 626 (sp < m->endp && !ISWORD(*sp)) ) && \ 627 (sp > m->beginp && ISWORD(*(sp-1)))) \ 628 629 /* 630 - backref - figure out what matched what, figuring in back references 631 == static const char *backref(struct match *m, const char *start, \ 632 == const char *stop, sopno startst, sopno stopst, sopno lev); 633 */ 634 static const char * /* == stop (success) or NULL (failure) */ 635 backref( 636 struct match *m, 637 const char *start, 638 const char *stop, 639 sopno startst, 640 sopno stopst, 641 sopno lev, /* PLUS nesting level */ 642 int rec) 643 { 644 int i; 645 sopno ss; /* start sop of current subRE */ 646 const char *sp; /* start of string matched by it */ 647 sopno ssub; /* start sop of subsubRE */ 648 sopno esub; /* end sop of subsubRE */ 649 const char *ssp; /* start of string matched by subsubRE */ 650 const char *dp; 651 size_t len; 652 int hard; 653 sop s; 654 regoff_t offsave; 655 cset *cs; 656 wint_t wc; 657 658 _DIAGASSERT(m != NULL); 659 _DIAGASSERT(start != NULL); 660 _DIAGASSERT(stop != NULL); 661 662 AT("back", start, stop, startst, stopst); 663 sp = start; 664 665 /* get as far as we can with easy stuff */ 666 hard = 0; 667 for (ss = startst; !hard && ss < stopst; ss++) 668 switch (OP(s = m->g->strip[ss])) { 669 case OCHAR: 670 if (sp == stop) 671 return(NULL); 672 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR); 673 if (wc != (wint_t)OPND(s)) 674 return(NULL); 675 break; 676 case OANY: 677 if (sp == stop) 678 return(NULL); 679 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR); 680 if (wc == BADCHAR) 681 return (NULL); 682 break; 683 case OANYOF: 684 if (sp == stop) 685 return (NULL); 686 cs = &m->g->sets[OPND(s)]; 687 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR); 688 if (wc == BADCHAR || !CHIN(cs, wc)) 689 return(NULL); 690 break; 691 case OBOS: 692 if (sp == m->beginp && (m->eflags & REG_NOTBOL) == 0) 693 { /* yes */ } 694 else 695 return(NULL); 696 break; 697 case OEOS: 698 if (sp == m->endp && (m->eflags & REG_NOTEOL) == 0) 699 { /* yes */ } 700 else 701 return(NULL); 702 break; 703 case OBOL: 704 if ((sp == m->beginp && !(m->eflags®_NOTBOL)) || 705 (sp > m->offp && sp < m->endp && 706 *(sp-1) == '\n' && (m->g->cflags®_NEWLINE))) 707 { /* yes */ } 708 else 709 return(NULL); 710 break; 711 case OEOL: 712 if ( (sp == m->endp && !(m->eflags®_NOTEOL)) || 713 (sp < m->endp && *sp == '\n' && 714 (m->g->cflags®_NEWLINE)) ) 715 { /* yes */ } 716 else 717 return(NULL); 718 break; 719 case OWBND: 720 if (ISBOW(m, sp) || ISEOW(m, sp)) 721 { /* yes */ } 722 else 723 return(NULL); 724 break; 725 case ONWBND: 726 if (((sp == m->beginp) && !ISWORD(*sp)) || 727 (sp == m->endp && !ISWORD(*(sp - 1)))) 728 { /* yes, beginning/end of subject */ } 729 else if (ISWORD(*(sp - 1)) == ISWORD(*sp)) 730 { /* yes, beginning/end of subject */ } 731 else 732 return(NULL); 733 break; 734 case OBOW: 735 if (ISBOW(m, sp)) 736 { /* yes */ } 737 else 738 return(NULL); 739 break; 740 case OEOW: 741 if (ISEOW(m, sp)) 742 { /* yes */ } 743 else 744 return(NULL); 745 break; 746 case O_QUEST: 747 break; 748 case OOR1: /* matches null but needs to skip */ 749 ss++; 750 s = m->g->strip[ss]; 751 do { 752 assert(OP(s) == OOR2); 753 ss += OPND(s); 754 } while (OP(s = m->g->strip[ss]) != (sop)O_CH); 755 /* note that the ss++ gets us past the O_CH */ 756 break; 757 default: /* have to make a choice */ 758 hard = 1; 759 break; 760 } 761 if (!hard) { /* that was it! */ 762 if (sp != stop) 763 return(NULL); 764 return(sp); 765 } 766 ss--; /* adjust for the for's final increment */ 767 768 /* the hard stuff */ 769 AT("hard", sp, stop, ss, stopst); 770 s = m->g->strip[ss]; 771 switch (OP(s)) { 772 case OBACK_: /* the vilest depths */ 773 i = OPND(s); 774 assert(0 < i && i <= m->g->nsub); 775 if (m->pmatch[i].rm_eo == -1) 776 return(NULL); 777 assert(m->pmatch[i].rm_so != -1); 778 len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so; 779 if (len == 0 && rec++ > MAX_RECURSION) 780 return(NULL); 781 assert(stop - m->beginp >= len); 782 if (sp > stop - len) 783 return(NULL); /* not enough left to match */ 784 ssp = m->offp + m->pmatch[i].rm_so; 785 if (memcmp(sp, ssp, len) != 0) 786 return(NULL); 787 while (m->g->strip[ss] != (sop)SOP(O_BACK, i)) 788 ss++; 789 return(backref(m, sp+len, stop, ss+1, stopst, lev, rec)); 790 case OQUEST_: /* to null or not */ 791 dp = backref(m, sp, stop, ss+1, stopst, lev, rec); 792 if (dp != NULL) 793 return(dp); /* not */ 794 return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev, rec)); 795 case OPLUS_: 796 assert(m->lastpos != NULL); 797 assert(lev+1 <= m->g->nplus); 798 m->lastpos[lev+1] = sp; 799 return(backref(m, sp, stop, ss+1, stopst, lev+1, rec)); 800 case O_PLUS: 801 if (sp == m->lastpos[lev]) /* last pass matched null */ 802 return(backref(m, sp, stop, ss+1, stopst, lev-1, rec)); 803 /* try another pass */ 804 m->lastpos[lev] = sp; 805 dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev, rec); 806 if (dp == NULL) 807 return(backref(m, sp, stop, ss+1, stopst, lev-1, rec)); 808 else 809 return(dp); 810 case OCH_: /* find the right one, if any */ 811 ssub = ss + 1; 812 esub = ss + OPND(s) - 1; 813 assert(OP(m->g->strip[esub]) == OOR1); 814 for (;;) { /* find first matching branch */ 815 dp = backref(m, sp, stop, ssub, esub, lev, rec); 816 if (dp != NULL) 817 return(dp); 818 /* that one missed, try next one */ 819 if (OP(m->g->strip[esub]) == (sop)O_CH) 820 return(NULL); /* there is none */ 821 esub++; 822 assert(OP(m->g->strip[esub]) == (sop)OOR2); 823 ssub = esub + 1; 824 esub += OPND(m->g->strip[esub]); 825 if (OP(m->g->strip[esub]) == (sop)OOR2) 826 esub--; 827 else 828 assert(OP(m->g->strip[esub]) == O_CH); 829 } 830 /* NOTREACHED */ 831 break; 832 case OLPAREN: /* must undo assignment if rest fails */ 833 i = OPND(s); 834 assert(0 < i && i <= m->g->nsub); 835 offsave = m->pmatch[i].rm_so; 836 m->pmatch[i].rm_so = sp - m->offp; 837 dp = backref(m, sp, stop, ss+1, stopst, lev, rec); 838 if (dp != NULL) 839 return(dp); 840 m->pmatch[i].rm_so = offsave; 841 return(NULL); 842 case ORPAREN: /* must undo assignment if rest fails */ 843 i = OPND(s); 844 assert(0 < i && i <= m->g->nsub); 845 offsave = m->pmatch[i].rm_eo; 846 m->pmatch[i].rm_eo = sp - m->offp; 847 dp = backref(m, sp, stop, ss+1, stopst, lev, rec); 848 if (dp != NULL) 849 return(dp); 850 m->pmatch[i].rm_eo = offsave; 851 return(NULL); 852 default: /* uh oh */ 853 assert(nope); 854 break; 855 } 856 857 /* "can't happen" */ 858 assert(nope); 859 /* NOTREACHED */ 860 return "shut up gcc"; 861 } 862 863 /* 864 - walk - step through the string either quickly or slowly 865 == static const char *walk(struct match *m, const char *start, \ 866 == const char *stop, sopno startst, sopno stopst, bool fast); 867 */ 868 static const char * /* where it ended, or NULL */ 869 walk(struct match *m, const char *start, const char *stop, sopno startst, 870 sopno stopst, bool fast) 871 { 872 states st = m->st; 873 states fresh = m->fresh; 874 states empty = m->empty; 875 states tmp = m->tmp; 876 const char *p = start; 877 wint_t c; 878 wint_t lastc; /* previous c */ 879 wint_t flagch; 880 int i, sflags; 881 const char *matchp; /* last p at which a match ended */ 882 size_t clen; 883 884 _DIAGASSERT(m != NULL); 885 _DIAGASSERT(start != NULL); 886 _DIAGASSERT(stop != NULL); 887 888 sflags = 0; 889 AT("walk", start, stop, startst, stopst); 890 CLEAR(st); 891 SET1(st, startst); 892 SP("sstart", st, *p); 893 st = step(m->g, startst, stopst, st, NOTHING, st, sflags); 894 if (fast) 895 ASSIGN(fresh, st); 896 matchp = NULL; 897 if (start == m->offp || (start == m->beginp && !(m->eflags®_NOTBOL))) 898 c = OUT; 899 else { 900 /* 901 * XXX Wrong if the previous character was multi-byte. 902 * Newline never is (in encodings supported by FreeBSD), 903 * so this only breaks the ISWORD tests below. 904 */ 905 c = (uch)*(start - 1); 906 } 907 for (;;) { 908 /* next character */ 909 lastc = c; 910 sflags = 0; 911 if (p == m->endp) { 912 c = OUT; 913 clen = 0; 914 } else 915 clen = XMBRTOWC(&c, p, m->endp - p, &m->mbs, BADCHAR); 916 917 if (fast && EQ(st, fresh)) 918 matchp = p; 919 920 /* is there an EOL and/or BOL between lastc and c? */ 921 flagch = '\0'; 922 i = 0; 923 if ( (lastc == '\n' && m->g->cflags®_NEWLINE) || 924 (lastc == OUT && !(m->eflags®_NOTBOL)) ) { 925 flagch = BOL; 926 i = m->g->nbol; 927 } 928 if ( (c == '\n' && m->g->cflags®_NEWLINE) || 929 (c == OUT && !(m->eflags®_NOTEOL)) ) { 930 flagch = (flagch == BOL) ? BOLEOL : EOL; 931 i += m->g->neol; 932 } 933 if (lastc == OUT && (m->eflags & REG_NOTBOL) == 0) { 934 sflags |= SBOS; 935 /* Step one more for BOS. */ 936 i++; 937 } 938 if (c == OUT && (m->eflags & REG_NOTEOL) == 0) { 939 sflags |= SEOS; 940 /* Step one more for EOS. */ 941 i++; 942 } 943 if (i != 0) { 944 for (; i > 0; i--) 945 st = step(m->g, startst, stopst, st, flagch, st, 946 sflags); 947 SP("sboleol", st, c); 948 } 949 950 /* how about a word boundary? */ 951 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) && 952 (c != OUT && ISWORD(c)) ) { 953 flagch = BOW; 954 } 955 if ( (lastc != OUT && ISWORD(lastc)) && 956 (flagch == EOL || (c != OUT && !ISWORD(c))) ) { 957 flagch = EOW; 958 } 959 if (flagch == BOW || flagch == EOW) { 960 st = step(m->g, startst, stopst, st, flagch, st, sflags); 961 SP("sboweow", st, c); 962 } 963 if (lastc != OUT && c != OUT && 964 ISWORD(lastc) == ISWORD(c)) { 965 flagch = NWBND; 966 } else if ((lastc == OUT && !ISWORD(c)) || 967 (c == OUT && !ISWORD(lastc))) { 968 flagch = NWBND; 969 } 970 if (flagch == NWBND) { 971 st = step(m->g, startst, stopst, st, flagch, st, sflags); 972 SP("snwbnd", st, c); 973 } 974 975 /* are we done? */ 976 if (ISSET(st, stopst)) { 977 if (fast) 978 break; 979 else 980 matchp = p; 981 } 982 if (EQ(st, empty) || p == stop || clen > (size_t)(stop - p)) 983 break; /* NOTE BREAK OUT */ 984 985 /* no, we must deal with this character */ 986 ASSIGN(tmp, st); 987 if (fast) 988 ASSIGN(st, fresh); 989 else 990 ASSIGN(st, empty); 991 assert(c != OUT); 992 st = step(m->g, startst, stopst, tmp, c, st, sflags); 993 SP("saft", st, c); 994 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st, sflags), 995 st)); 996 p += clen; 997 } 998 999 if (fast) { 1000 assert(matchp != NULL); 1001 m->coldp = matchp; 1002 if (ISSET(st, stopst)) 1003 return (p + XMBRTOWC(NULL, p, stop - p, &m->mbs, 0)); 1004 else 1005 return (NULL); 1006 } else 1007 return (matchp); 1008 } 1009 1010 /* 1011 - step - map set of states reachable before char to set reachable after 1012 == static states step(struct re_guts *g, sopno start, sopno stop, \ 1013 == states bef, int ch, states aft); 1014 == #define BOL (OUT-1) 1015 == #define EOL (BOL-1) 1016 == #define BOLEOL (BOL-2) 1017 == #define NOTHING (BOL-3) 1018 == #define BOW (BOL-4) 1019 == #define EOW (BOL-5) 1020 == #define BADCHAR (BOL-6) 1021 == #define NONCHAR(c) ((c) <= OUT) 1022 */ 1023 static states 1024 step(struct re_guts *g, 1025 sopno start, /* start state within strip */ 1026 sopno stop, /* state after stop state within strip */ 1027 states bef, /* states reachable before */ 1028 wint_t ch, /* character or NONCHAR code */ 1029 states aft, /* states already known reachable after */ 1030 int sflags) /* state flags */ 1031 { 1032 cset *cs; 1033 sop s; 1034 sopno pc; 1035 onestate here; /* note, macros know this name */ 1036 sopno look; 1037 int i; 1038 1039 _DIAGASSERT(g != NULL); 1040 1041 for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) { 1042 s = g->strip[pc]; 1043 switch (OP(s)) { 1044 case OEND: 1045 assert(pc == stop-1); 1046 break; 1047 case OCHAR: 1048 /* only characters can match */ 1049 assert(!NONCHAR(ch) || ch != OPND(s)); 1050 if (ch == (wint_t)OPND(s)) 1051 FWD(aft, bef, 1); 1052 break; 1053 case OBOS: 1054 if ((ch == BOL || ch == BOLEOL) && (sflags & SBOS) != 0) 1055 FWD(aft, bef, 1); 1056 break; 1057 case OEOS: 1058 if ((ch == EOL || ch == BOLEOL) && (sflags & SEOS) != 0) 1059 FWD(aft, bef, 1); 1060 break; 1061 case OBOL: 1062 if (ch == BOL || ch == BOLEOL) 1063 FWD(aft, bef, 1); 1064 break; 1065 case OEOL: 1066 if (ch == EOL || ch == BOLEOL) 1067 FWD(aft, bef, 1); 1068 break; 1069 case OBOW: 1070 if (ch == BOW) 1071 FWD(aft, bef, 1); 1072 break; 1073 case OEOW: 1074 if (ch == EOW) 1075 FWD(aft, bef, 1); 1076 break; 1077 case OWBND: 1078 if (ch == BOW || ch == EOW) 1079 FWD(aft, bef, 1); 1080 break; 1081 case ONWBND: 1082 if (ch == NWBND) 1083 FWD(aft, aft, 1); 1084 break; 1085 case OANY: 1086 if (!NONCHAR(ch)) 1087 FWD(aft, bef, 1); 1088 break; 1089 case OANYOF: 1090 cs = &g->sets[OPND(s)]; 1091 if (!NONCHAR(ch) && CHIN(cs, ch)) 1092 FWD(aft, bef, 1); 1093 break; 1094 case OBACK_: /* ignored here */ 1095 case O_BACK: 1096 FWD(aft, aft, 1); 1097 break; 1098 case OPLUS_: /* forward, this is just an empty */ 1099 FWD(aft, aft, 1); 1100 break; 1101 case O_PLUS: /* both forward and back */ 1102 FWD(aft, aft, 1); 1103 i = ISSETBACK(aft, OPND(s)); 1104 BACK(aft, aft, OPND(s)); 1105 if (!i && ISSETBACK(aft, OPND(s))) { 1106 /* oho, must reconsider loop body */ 1107 pc -= OPND(s) + 1; 1108 INIT(here, pc); 1109 } 1110 break; 1111 case OQUEST_: /* two branches, both forward */ 1112 FWD(aft, aft, 1); 1113 FWD(aft, aft, OPND(s)); 1114 break; 1115 case O_QUEST: /* just an empty */ 1116 FWD(aft, aft, 1); 1117 break; 1118 case OLPAREN: /* not significant here */ 1119 case ORPAREN: 1120 FWD(aft, aft, 1); 1121 break; 1122 case OCH_: /* mark the first two branches */ 1123 FWD(aft, aft, 1); 1124 assert(OP(g->strip[pc+OPND(s)]) == (sop)OOR2); 1125 FWD(aft, aft, OPND(s)); 1126 break; 1127 case OOR1: /* done a branch, find the O_CH */ 1128 if (ISSTATEIN(aft, here)) { 1129 for (look = 1; 1130 OP(s = g->strip[pc+look]) != (sop)O_CH; 1131 look += OPND(s)) 1132 assert(OP(s) == (sop)OOR2); 1133 FWD(aft, aft, look + 1); 1134 } 1135 break; 1136 case OOR2: /* propagate OCH_'s marking */ 1137 FWD(aft, aft, 1); 1138 if (OP(g->strip[pc+OPND(s)]) != (sop)O_CH) { 1139 assert(OP(g->strip[pc+OPND(s)]) == (sop)OOR2); 1140 FWD(aft, aft, OPND(s)); 1141 } 1142 break; 1143 case O_CH: /* just empty */ 1144 FWD(aft, aft, 1); 1145 break; 1146 default: /* ooooops... */ 1147 assert(nope); 1148 break; 1149 } 1150 } 1151 1152 return(aft); 1153 } 1154 1155 #ifdef REDEBUG 1156 /* 1157 - print - print a set of states 1158 == #ifdef REDEBUG 1159 == static void print(struct match *m, const char *caption, states st, \ 1160 == int ch, FILE *d); 1161 == #endif 1162 */ 1163 static void 1164 print(struct match *m, 1165 const char *caption, 1166 states st, 1167 int ch, 1168 FILE *d) 1169 { 1170 struct re_guts *g = m->g; 1171 sopno i; 1172 int first = 1; 1173 1174 _DIAGASSERT(m != NULL); 1175 _DIAGASSERT(caption != NULL); 1176 1177 if (!(m->eflags®_TRACE)) 1178 return; 1179 1180 _DIAGASSERT(d != NULL); 1181 1182 fprintf(d, "%s", caption); 1183 if (ch != '\0') 1184 fprintf(d, " %s", pchar(ch)); 1185 for (i = 0; i < g->nstates; i++) 1186 if (ISSET(st, i)) { 1187 fprintf(d, "%s%lu", (first) ? "\t" : ", ", i); 1188 first = 0; 1189 } 1190 fprintf(d, "\n"); 1191 } 1192 1193 /* 1194 - at - print current situation 1195 == #ifdef REDEBUG 1196 == static void at(struct match *m, const char *title, const char *start, \ 1197 == const char *stop, sopno startst, sopno stopst); 1198 == #endif 1199 */ 1200 static void 1201 at( struct match *m, 1202 const char *title, 1203 const char *start, 1204 const char *stop, 1205 sopno startst, 1206 sopno stopst) 1207 { 1208 1209 _DIAGASSERT(m != NULL); 1210 _DIAGASSERT(title != NULL); 1211 _DIAGASSERT(start != NULL); 1212 _DIAGASSERT(stop != NULL); 1213 1214 if (!(m->eflags®_TRACE)) 1215 return; 1216 1217 printf("%s %s-", title, pchar(*start)); 1218 printf("%s ", pchar(*stop)); 1219 printf("%ld-%ld\n", (long)startst, (long)stopst); 1220 } 1221 1222 #ifndef PCHARDONE 1223 #define PCHARDONE /* never again */ 1224 /* 1225 - pchar - make a character printable 1226 == #ifdef REDEBUG 1227 == static const char *pchar(int ch); 1228 == #endif 1229 * 1230 * Is this identical to regchar() over in debug.c? Well, yes. But a 1231 * duplicate here avoids having a debugging-capable regexec.o tied to 1232 * a matching debug.o, and this is convenient. It all disappears in 1233 * the non-debug compilation anyway, so it doesn't matter much. 1234 */ 1235 static const char * /* -> representation */ 1236 pchar(int ch) 1237 { 1238 static char pbuf[10]; 1239 1240 if (isprint((uch)ch) || ch == ' ') 1241 snprintf(pbuf, sizeof(pbuf), "%c", ch); 1242 else 1243 snprintf(pbuf, sizeof(pbuf), "\\%o", ch); 1244 return(pbuf); 1245 } 1246 #endif 1247 #endif 1248 1249 #undef stepback 1250 #undef matcher 1251 #undef walk 1252 #undef dissect 1253 #undef backref 1254 #undef step 1255 #undef print 1256 #undef at 1257 #undef match 1258
Indexes created Sat Sep 20 22:09:52 GMT 2025