regex/TRE/lib/regexec.c

   1 /*
   2   tre_regexec.c - TRE POSIX compatible matching functions (and more).
   3
   4   This software is released under a BSD-style license.
   5   See the file LICENSE for details and copyright.
   6
   7 */
   8
   9 #ifdef HAVE_CONFIG_H
  10 #include <config.h>
  11 #endif /* HAVE_CONFIG_H */
  12
  13 /* Unset TRE_USE_ALLOCA to avoid using the stack to hold all the state
  14    info while running */
  15 #undef TRE_USE_ALLOCA
  16
  17 #ifdef TRE_USE_ALLOCA
  18 /* AIX requires this to be the first thing in the file.  */
  19 #ifndef __GNUC__
  20 # if HAVE_ALLOCA_H
  21 #  include <alloca.h>
  22 # else
  23 #  ifdef _AIX
  24  #pragma alloca
  25 #  else
  26 #   ifndef alloca /* predefined by HP cc +Olibcalls */
  27 char *alloca ();
  28 #   endif
  29 #  endif
  30 # endif
  31 #endif
  32 #endif /* TRE_USE_ALLOCA */
  33
  34 #include <assert.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #ifdef HAVE_WCHAR_H
  38 #include <wchar.h>
  39 #endif /* HAVE_WCHAR_H */
  40 #ifdef HAVE_WCTYPE_H
  41 #include <wctype.h>
  42 #endif /* HAVE_WCTYPE_H */
  43 #ifndef TRE_WCHAR
  44 #include <ctype.h>
  45 #endif /* !TRE_WCHAR */
  46 #ifdef HAVE_MALLOC_H
  47 #include <malloc.h>
  48 #endif /* HAVE_MALLOC_H */
  49 #include <limits.h>
  50
  51 #include "tre-internal.h"
  52 #include "tre-match-utils.h"
  53 #include "tre.h"
  54 #include "xmalloc.h"
  55
  56
  57 /* For each tre_last_matched_t in the lm array, find the last matched branch by
  58    comparing the touch value of the cmp_tag's.  For all other branches, reset
  59    the corresponding tags.  If reset_all is non-zero, reset all tags in all
  60    branches.  Recurse into the nested last matched structures, clearing tags as
  61    apprpriate. */
  62 static void
  63 tre_reset_last_matched_branches(tre_tag_t *tags, const tre_last_matched_t *lm,
  64                                 int n, int start_tag, int reset_all)
  65 {
  66   int max, i, reset;
  67   tre_last_matched_branch_t *b;
  68
  69   DPRINT(("tre_reset_last_matched_branches: n=%d start_tag=%d reset_all=%d\n",
  70           n, start_tag, reset_all));
  71   for (; n-- > 0; lm++)
  72     {
  73       if (lm->n_branches == 1)
  74         {
  75           b = lm->branches;
  76           if (start_tag > 0)
  77             {
  78               DPRINT(("  b->cmp_tag=%d %d <? %d\n", b->cmp_tag,
  79                       tre_tag_touch_get(tags, b->cmp_tag),
  80                       tre_tag_touch_get(tags, start_tag)));
  81               reset = (reset_all || tre_tag_touch_get(tags, b->cmp_tag) <
  82                        tre_tag_touch_get(tags, start_tag));
  83             }
  84           else
  85             reset = 0;
  86
  87           if (reset)
  88             {
  89               int *t;
  90
  91               for (i = b->n_tags, t = b->tags; i > 0; i--, t++)
  92                 {
  93                   DPRINT(("  Resetting t%d\n", *t));
  94                   tre_tag_reset(tags, *t);
  95                 }
  96             }
  97           if (b->n_last_matched > 0)
  98             tre_reset_last_matched_branches(tags, b->last_matched,
  99                                                 b->n_last_matched,
 100                                                 lm->start_tag, reset);
 101         }
 102       else
 103         {
 104           if (!reset_all)
 105             {
 106 #ifdef TRE_DEBUG
 107               int last;
 108 #endif /* TRE_DEBUG */
 109               max = 0;
 110               for (i = lm->n_branches, b = lm->branches; i > 0; i--, b++)
 111                 {
 112                   int t = b->cmp_tag;
 113                   int touch = tre_tag_touch_get(tags, t);
 114                   if (touch > max)
 115                     {
 116                       max = touch;
 117 #ifdef TRE_DEBUG
 118                       last = t;
 119 #endif /* TRE_DEBUG */
 120                     }
 121                 }
 122               DPRINT(("  Last touched end tag t%d=%d\n", last, max));
 123             }
 124
 125           for (i = lm->n_branches, b = lm->branches; i > 0; i--, b++)
 126             {
 127               reset = (reset_all || tre_tag_touch_get(tags, b->cmp_tag) < max);
 128               if (reset)
 129                 {
 130                   int j;
 131                   int *t;
 132
 133                   for (j = b->n_tags, t = b->tags; j > 0; j--, t++)
 134                     {
 135                       DPRINT(("  Resetting t%d\n", *t));
 136                       tre_tag_reset(tags, *t);
 137                     }
 138                 }
 139               if (b->n_last_matched > 0)
 140                 tre_reset_last_matched_branches(tags, b->last_matched,
 141                                                 b->n_last_matched,
 142                                                 lm->start_tag, reset);
 143             }
 144         }
 145     }
 146 }
 147
 148
 149 /* Fills the POSIX.2 regmatch_t array according to the TNFA tag and match
 150    endpoint values. */
 151 reg_errcode_t
 152 tre_fill_pmatch(size_t nmatch, regmatch_t pmatch[], int cflags,
 153                 const tre_tnfa_t *tnfa, const tre_tag_t *intags, int match_eo)
 154 {
 155   unsigned int i;
 156
 157   if (cflags & REG_NOSUB) return REG_OK;
 158
 159   i = 0;
 160   if (match_eo >= 0 && intags)
 161     {
 162       const tre_tag_t *tags = intags;
 163       tre_submatch_data_t *submatch_data;
 164
 165       if (tnfa->last_matched_branch &&
 166           tnfa->last_matched_branch->n_last_matched > 0)
 167         {
 168           tre_tag_t *t;
 169 #ifdef TRE_USE_ALLOCA
 170           t = alloca(sizeof(*t) * tnfa->num_tags);
 171 #else /* !TRE_USE_ALLOCA */
 172           t = xmalloc(sizeof(*t) * tnfa->num_tags);
 173 #endif /* !TRE_USE_ALLOCA */
 174           if (!t) return REG_ESPACE;
 175           memcpy(t, intags, tnfa->num_tags * sizeof(tre_tag_t));
 176           tre_reset_last_matched_branches(t,
 177                                     tnfa->last_matched_branch->last_matched,
 178                                     tnfa->last_matched_branch->n_last_matched,
 179                                     0, 0);
 180           tags = t;
 181         }
 182       /* Construct submatch offsets from the tags. */
 183       DPRINT(("end tag = t%d = %d\n", tnfa->end_tag, match_eo));
 184       submatch_data = tnfa->submatch_data;
 185       while (i < tnfa->num_submatches && i < nmatch)
 186         {
 187           if (submatch_data[i].so_tag == tnfa->end_tag)
 188             pmatch[i].rm_so = match_eo;
 189           else
 190             pmatch[i].rm_so = tre_tag_get(tags, submatch_data[i].so_tag);
 191
 192           if (submatch_data[i].eo_tag == tnfa->end_tag)
 193             pmatch[i].rm_eo = match_eo;
 194           else
 195             pmatch[i].rm_eo = tre_tag_get(tags, submatch_data[i].eo_tag);
 196
 197           /* If either of the endpoints were not used, this submatch
 198              was not part of the match. */
 199           if (pmatch[i].rm_so == -1 || pmatch[i].rm_eo == -1)
 200             pmatch[i].rm_so = pmatch[i].rm_eo = -1;
 201
 202           DPRINT(("pmatch[%d] = {t%d = %qd, t%d = %qd}\n", i,
 203                   submatch_data[i].so_tag, pmatch[i].rm_so,
 204                   submatch_data[i].eo_tag, pmatch[i].rm_eo));
 205           i++;
 206         }
 207 #ifndef TRE_USE_ALLOCA
 208         if (tags != intags) xfree(tags);
 209 #endif /* !TRE_USE_ALLOCA */
 210     }
 211
 212   while (i < nmatch)
 213     {
 214       pmatch[i].rm_so = -1;
 215       pmatch[i].rm_eo = -1;
 216       i++;
 217     }
 218
 219   return REG_OK;
 220 }
 221
 222
 223 /*
 224   Wrapper functions for POSIX compatible regexp matching.
 225 */
 226
 227 #ifndef __LIBC__
 228 int
 229 tre_have_backrefs(const regex_t *preg)
 230 {
 231   tre_tnfa_t *tnfa = (void *)preg->TRE_REGEX_T_FIELD;
 232   return tnfa->have_backrefs;
 233 }
 234
 235 #ifdef TRE_APPROX
 236 int
 237 tre_have_approx(const regex_t *preg)
 238 {
 239   tre_tnfa_t *tnfa = (void *)preg->TRE_REGEX_T_FIELD;
 240   return tnfa->have_approx;
 241 }
 242 #endif /* TRE_APPROX */
 243 #endif /* !__LIBC__ */
 244
 245 static int
 246 tre_match(const tre_tnfa_t *tnfa, const void *string, size_t len,
 247           tre_str_type_t type, size_t nmatch, regmatch_t pmatch[],
 248           int eflags)
 249 {
 250   reg_errcode_t status;
 251   tre_tag_t *tags = NULL;
 252   int eo;
 253   size_t offset = 0, count = 0;
 254   if (tnfa->num_tags > 0 && nmatch > 0)
 255     {
 256 #ifdef TRE_USE_ALLOCA
 257       tags = alloca(sizeof(*tags) * tnfa->num_tags);
 258 #else /* !TRE_USE_ALLOCA */
 259       tags = xmalloc(sizeof(*tags) * tnfa->num_tags);
 260 #endif /* !TRE_USE_ALLOCA */
 261       if (tags == NULL)
 262         return REG_ESPACE;
 263     }
 264
 265   if (
 266 #ifdef TRE_STR_USER
 267       type != STR_USER &&
 268 #endif /* TRE_STR_USER */
 269       (eflags & REG_STARTEND) && pmatch)
 270     {
 271       if (pmatch->rm_so < 0)
 272         return REG_INVARG;
 273       if (len == (size_t)-1)
 274         {
 275           if (pmatch->rm_eo < 0 || pmatch->rm_so > pmatch->rm_eo)
 276             return REG_INVARG;
 277           len = pmatch->rm_eo - pmatch->rm_so;
 278         }
 279       count = offset = pmatch->rm_so;
 280       if (type == STR_WIDE) offset *= sizeof(wchar_t);
 281     }
 282
 283   /* Dispatch to the appropriate matcher. */
 284   if (tnfa->have_backrefs || eflags & REG_BACKTRACKING_MATCHER)
 285     {
 286       /* The regex has back references, use the backtracking matcher. */
 287 #ifdef TRE_STR_USER
 288       if (type == STR_USER)
 289         {
 290           const tre_str_source *source = string;
 291           if (source->rewind == NULL || source->compare == NULL)
 292             /* The backtracking matcher requires rewind and compare
 293                capabilities from the input stream. */
 294             return REG_BADPAT;
 295         }
 296 #endif /* TRE_STR_USER */
 297       status = tre_tnfa_run_backtrack(tnfa, string + offset, (int)len, type,
 298                                       tags, eflags, &eo);
 299     }
 300 #ifdef TRE_APPROX
 301   else if (tnfa->have_approx || eflags & REG_APPROX_MATCHER)
 302     {
 303       /* The regex uses approximate matching, use the approximate matcher. */
 304       regamatch_t match;
 305       regaparams_t params;
 306       tre_regaparams_default(&params);
 307       params.max_err = 0;
 308       params.max_cost = 0;
 309       status = tre_tnfa_run_approx(tnfa, string + offset, (int)len, type, tags,
 310                                    &match, params, eflags, &eo);
 311     }
 312 #endif /* TRE_APPROX */
 313   else
 314     {
 315       /* Exact matching, no back references, use the parallel matcher. */
 316       status = tre_tnfa_run_parallel(tnfa, string + offset, (int)len, type,
 317                                      tags, eflags, &eo);
 318     }
 319
 320   if (status == REG_OK)
 321     {
 322       /* A match was found, so fill the submatch registers. */
 323       status = tre_fill_pmatch(nmatch, pmatch, tnfa->cflags, tnfa, tags, eo);
 324       /* If doing REG_STARTEND, adjust the pmatch array (we can't build
 325          this into tre_fill_pmatch, because tre_tnfa_run_backtrack calls
 326          tre_fill_pmatch itself). */
 327       if (status == REG_OK && !(tnfa->cflags & REG_NOSUB) &&
 328 #ifdef TRE_STR_USER
 329           type != STR_USER &&
 330 #endif /* TRE_STR_USER */
 331           (eflags & REG_STARTEND) && pmatch && nmatch > 0)
 332         {
 333           size_t i;
 334           regmatch_t *p;
 335           for (i = nmatch, p = pmatch; i > 0; p++, i--)
 336             {
 337               if (p->rm_so >= 0) p->rm_so += count;
 338               if (p->rm_eo >= 0) p->rm_eo += count;
 339             }
 340         }
 341     }
 342 #ifndef TRE_USE_ALLOCA
 343   if (tags)
 344     xfree(tags);
 345 #endif /* !TRE_USE_ALLOCA */
 346   return status;
 347 }
 348
 349 int
 350 tre_regnexec(const regex_t *preg, const char *str, size_t len,
 351          size_t nmatch, regmatch_t pmatch[], int eflags)
 352 {
 353   tre_tnfa_t *tnfa = (void *)preg->TRE_REGEX_T_FIELD;
 354   tre_str_type_t type = (TRE_MB_CUR_MAX_L(tnfa->loc) == 1) ? STR_BYTE : STR_MBS;
 355
 356 #ifdef TRE_USE_SYSTEM_REGEX_H
 357   if (preg->re_magic != RE_MAGIC) return REG_BADPAT;
 358 #endif /* TRE_USE_SYSTEM_REGEX_H */
 359
 360   return tre_match(tnfa, str, len, type, nmatch, pmatch, eflags);
 361 }
 362
 363 int
 364 tre_regexec(const regex_t *preg, const char *str,
 365         size_t nmatch, regmatch_t pmatch[], int eflags)
 366 {
 367   return tre_regnexec(preg, str, (size_t)-1, nmatch, pmatch, eflags);
 368 }
 369
 370
 371 #ifdef TRE_WCHAR
 372
 373 int
 374 tre_regwnexec(const regex_t *preg, const wchar_t *str, size_t len,
 375           size_t nmatch, regmatch_t pmatch[], int eflags)
 376 {
 377   tre_tnfa_t *tnfa = (void *)preg->TRE_REGEX_T_FIELD;
 378
 379 #ifdef TRE_USE_SYSTEM_REGEX_H
 380   if (preg->re_magic != RE_MAGIC) return REG_BADPAT;
 381 #endif /* TRE_USE_SYSTEM_REGEX_H */
 382
 383   return tre_match(tnfa, str, len, STR_WIDE, nmatch, pmatch, eflags);
 384 }
 385
 386 int
 387 tre_regwexec(const regex_t *preg, const wchar_t *str,
 388          size_t nmatch, regmatch_t pmatch[], int eflags)
 389 {
 390   return tre_regwnexec(preg, str, (size_t)-1, nmatch, pmatch, eflags);
 391 }
 392
 393 #endif /* TRE_WCHAR */
 394
 395 #ifdef TRE_STR_USER
 396 int
 397 tre_reguexec(const regex_t *preg, const tre_str_source *str,
 398          size_t nmatch, regmatch_t pmatch[], int eflags)
 399 {
 400   tre_tnfa_t *tnfa = (void *)preg->TRE_REGEX_T_FIELD;
 401
 402 #ifdef TRE_USE_SYSTEM_REGEX_H
 403   if (preg->re_magic != RE_MAGIC) return REG_BADPAT;
 404 #endif /* TRE_USE_SYSTEM_REGEX_H */
 405
 406   return tre_match(tnfa, str, (size_t)-1, STR_USER, nmatch, pmatch, eflags);
 407 }
 408 #endif /* TRE_STR_USER */
 409
 410
 411 #ifdef TRE_APPROX
 412
 413 /*
 414   Wrapper functions for approximate regexp matching.
 415 */
 416
 417 static int
 418 tre_match_approx(const tre_tnfa_t *tnfa, const void *string, size_t len,
 419                  tre_str_type_t type, regamatch_t *match, regaparams_t params,
 420                  int eflags)
 421 {
 422   reg_errcode_t status;
 423   tre_tag_t *tags = NULL;
 424   int eo;
 425   size_t offset = 0, count = 0;
 426
 427   /* If the regexp does not use approximate matching features, the
 428      maximum cost is zero, and the approximate matcher isn't forced,
 429      use the exact matcher instead. */
 430   if (params.max_cost == 0 && !tnfa->have_approx
 431       && !(eflags & REG_APPROX_MATCHER))
 432     return tre_match(tnfa, string, len, type, match->nmatch, match->pmatch,
 433                      eflags);
 434
 435   /* Back references are not supported by the approximate matcher. */
 436   if (tnfa->have_backrefs)
 437     return REG_BADPAT;
 438
 439   if (tnfa->num_tags > 0 && match->nmatch > 0)
 440     {
 441 #if TRE_USE_ALLOCA
 442       tags = alloca(sizeof(*tags) * tnfa->num_tags);
 443 #else /* !TRE_USE_ALLOCA */
 444       tags = xmalloc(sizeof(*tags) * tnfa->num_tags);
 445 #endif /* !TRE_USE_ALLOCA */
 446       if (tags == NULL)
 447         return REG_ESPACE;
 448     }
 449
 450   if (
 451 #ifdef TRE_STR_USER
 452       type != STR_USER &&
 453 #endif /* TRE_STR_USER */
 454       (eflags & REG_STARTEND) && match->pmatch)
 455     {
 456       if (match->pmatch->rm_so < 0)
 457         return REG_INVARG;
 458       if (len == (size_t)-1)
 459         {
 460           if (match->pmatch->rm_eo < 0 || match->pmatch->rm_so >
 461               match->pmatch->rm_eo)
 462             return REG_INVARG;
 463           len = match->pmatch->rm_eo - match->pmatch->rm_so;
 464         }
 465       count = offset = match->pmatch->rm_so;
 466       if (type == STR_WIDE) offset *= sizeof(wchar_t);
 467     }
 468
 469   status = tre_tnfa_run_approx(tnfa, string, (int)len, type, tags,
 470                                match, params, eflags, &eo);
 471   if (status == REG_OK)
 472     {
 473       status = tre_fill_pmatch(match->nmatch, match->pmatch, tnfa->cflags,
 474                                tnfa, tags, eo);
 475       /* If doing REG_STARTEND, adjust the pmatch array (we can't build
 476          this into tre_fill_pmatch, because tre_tnfa_run_backtrack call
 477          tre_fill_pmatch itself). */
 478       if (status == REG_OK && !(tnfa->cflags & REG_NOSUB) &&
 479 #ifdef TRE_STR_USER
 480           type != STR_USER &&
 481 #endif /* TRE_STR_USER */
 482           (eflags & REG_STARTEND) && match->pmatch && match->nmatch > 0)
 483         {
 484           size_t i;
 485           regmatch_t *p;
 486           for (i = match->nmatch, p = match->pmatch; i > 0; p++, i--)
 487             {
 488               if (p->rm_so >= 0) p->rm_so += count;
 489               if (p->rm_eo >= 0) p->rm_eo += count;
 490             }
 491         }
 492     }
 493 #ifndef TRE_USE_ALLOCA
 494   if (tags)
 495     xfree(tags);
 496 #endif /* !TRE_USE_ALLOCA */
 497   return status;
 498 }
 499
 500 int
 501 tre_reganexec(const regex_t *preg, const char *str, size_t len,
 502           regamatch_t *match, regaparams_t params, int eflags)
 503 {
 504   tre_tnfa_t *tnfa = (void *)preg->TRE_REGEX_T_FIELD;
 505   tre_str_type_t type = (TRE_MB_CUR_MAX_L(tnfa->loc) == 1) ? STR_BYTE : STR_MBS;
 506
 507 #ifdef TRE_USE_SYSTEM_REGEX_H
 508   if (preg->re_magic != RE_MAGIC) return REG_BADPAT;
 509 #endif /* TRE_USE_SYSTEM_REGEX_H */
 510
 511   return tre_match_approx(tnfa, str, len, type, match, params, eflags);
 512 }
 513
 514 int
 515 tre_regaexec(const regex_t *preg, const char *str,
 516          regamatch_t *match, regaparams_t params, int eflags)
 517 {
 518   return tre_reganexec(preg, str, (size_t)-1, match, params, eflags);
 519 }
 520
 521 #ifdef TRE_WCHAR
 522
 523 int
 524 tre_regawnexec(const regex_t *preg, const wchar_t *str, size_t len,
 525            regamatch_t *match, regaparams_t params, int eflags)
 526 {
 527   tre_tnfa_t *tnfa = (void *)preg->TRE_REGEX_T_FIELD;
 528
 529 #ifdef TRE_USE_SYSTEM_REGEX_H
 530   if (preg->re_magic != RE_MAGIC) return REG_BADPAT;
 531 #endif /* TRE_USE_SYSTEM_REGEX_H */
 532
 533   return tre_match_approx(tnfa, str, len, STR_WIDE,
 534                           match, params, eflags);
 535 }
 536
 537 int
 538 tre_regawexec(const regex_t *preg, const wchar_t *str,
 539           regamatch_t *match, regaparams_t params, int eflags)
 540 {
 541   return tre_regawnexec(preg, str, (size_t)-1, match, params, eflags);
 542 }
 543
 544 #endif /* TRE_WCHAR */
 545
 546 void
 547 tre_regaparams_default(regaparams_t *params)
 548 {
 549   memset(params, 0, sizeof(*params));
 550   params->cost_ins = 1;
 551   params->cost_del = 1;
 552   params->cost_subst = 1;
 553   params->max_cost = INT_MAX;
 554   params->max_ins = INT_MAX;
 555   params->max_del = INT_MAX;
 556   params->max_subst = INT_MAX;
 557   params->max_err = INT_MAX;
 558 }
 559
 560 #endif /* TRE_APPROX */
 561
 562 /* EOF */