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