upgrade to latest upstream TRE regex code (0.8.0)

the main practical results of this change are
1. the regex code is no longer subject to LGPL; it's now 2-clause BSD
2. most (all?) popular nonstandard regex extensions are supported

I hesitate to call this a "sync" since both the old and new code are
heavily modified. in one sense, the old code was "more severely"
modified, in that it was actively hostile to non-strictly-conforming
expressions. on the other hand, the new code has eliminated the
useless translation of the entire regex string to wchar_t prior to
compiling, and now only converts multibyte character literals as
needed.

in the future i may use this modified TRE as a basis for writing the
long-planned new regex engine that will avoid multibyte-to-wide
character conversion entirely by compiling multibyte bracket
expressions specific to UTF-8.

1 files changed, 145 insertions, 241 deletions

diff --git a/src/regex/regexec.c b/src/regex/regexec.c
index f7aef506..79874ca5 100644
--- a/src/regex/regexec.c
+++ b/src/regex/regexec.c
@@ -1,21 +1,31 @@
 /*
   regexec.c - TRE POSIX compatible matching functions (and more).
 
-  Copyright (c) 2001-2006 Ville Laurikari <vl@iki.fi>.
-
-  This library is free software; you can redistribute it and/or
-  modify it under the terms of the GNU Lesser General Public
-  License as published by the Free Software Foundation; either
-  version 2.1 of the License, or (at your option) any later version.
-
-  This library is distributed in the hope that it will be useful,
-  but WITHOUT ANY WARRANTY; without even the implied warranty of
-  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-  Lesser General Public License for more details.
-
-  You should have received a copy of the GNU Lesser General Public
-  License along with this library; if not, write to the Free Software
-  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+  Copyright (c) 2001-2009 Ville Laurikari <vl@iki.fi>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions
+  are met:
+
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS
+  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
+  HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 */
 
@@ -48,13 +58,40 @@ tre_fill_pmatch(size_t nmatch, regmatch_t pmatch[], int cflags,
     str_byte += pos_add_next;                                                 \
   } while (0)
 
+#define IS_WORD_CHAR(c)	 ((c) == L'_' || tre_isalnum(c))
+
 #define CHECK_ASSERTIONS(assertions)					      \
   (((assertions & ASSERT_AT_BOL)					      \
     && (pos > 0 || reg_notbol)						      \
     && (prev_c != L'\n' || !reg_newline))				      \
    || ((assertions & ASSERT_AT_EOL)					      \
        && (next_c != L'\0' || reg_noteol)				      \
-       && (next_c != L'\n' || !reg_newline)))
+       && (next_c != L'\n' || !reg_newline))				      \
+   || ((assertions & ASSERT_AT_BOW)					      \
+       && (IS_WORD_CHAR(prev_c) || !IS_WORD_CHAR(next_c)))	              \
+   || ((assertions & ASSERT_AT_EOW)					      \
+       && (!IS_WORD_CHAR(prev_c) || IS_WORD_CHAR(next_c)))		      \
+   || ((assertions & ASSERT_AT_WB)					      \
+       && (pos != 0 && next_c != L'\0'					      \
+	   && IS_WORD_CHAR(prev_c) == IS_WORD_CHAR(next_c)))		      \
+   || ((assertions & ASSERT_AT_WB_NEG)					      \
+       && (pos == 0 || next_c == L'\0'					      \
+	   || IS_WORD_CHAR(prev_c) != IS_WORD_CHAR(next_c))))
+
+#define CHECK_CHAR_CLASSES(trans_i, tnfa, eflags)                             \
+  (((trans_i->assertions & ASSERT_CHAR_CLASS)                                 \
+       && !(tnfa->cflags & REG_ICASE)                                         \
+       && !tre_isctype((tre_cint_t)prev_c, trans_i->u.class))                 \
+    || ((trans_i->assertions & ASSERT_CHAR_CLASS)                             \
+        && (tnfa->cflags & REG_ICASE)                                         \
+        && !tre_isctype(tre_tolower((tre_cint_t)prev_c),trans_i->u.class)     \
+	&& !tre_isctype(tre_toupper((tre_cint_t)prev_c),trans_i->u.class))    \
+    || ((trans_i->assertions & ASSERT_CHAR_CLASS_NEG)                         \
+        && tre_neg_char_classes_match(trans_i->neg_classes,(tre_cint_t)prev_c,\
+                                      tnfa->cflags & REG_ICASE)))
+
+
+
 
 /* Returns 1 if `t1' wins `t2', 0 otherwise. */
 static int
@@ -86,7 +123,6 @@ tre_tag_order(int num_tags, tre_tag_direction_t *tag_directions,
 static int
 tre_neg_char_classes_match(tre_ctype_t *classes, tre_cint_t wc, int icase)
 {
-  DPRINT(("neg_char_classes_test: %p, %d, %d\n", classes, wc, icase));
   while (*classes != (tre_ctype_t)0)
     if ((!icase && tre_isctype(wc, *classes))
 	|| (icase && (tre_isctype(tre_toupper(wc), *classes)
@@ -118,7 +154,6 @@ tre_neg_char_classes_match(tre_ctype_t *classes, tre_cint_t wc, int icase)
   See `tre-match-backtrack.c'.
 */
 
-
 typedef struct {
   tre_tnfa_transition_t *state;
   int *tags;
@@ -130,41 +165,16 @@ typedef struct {
 } tre_reach_pos_t;
 
 
-#ifdef TRE_DEBUG
-static void
-tre_print_reach(const tre_tnfa_t *tnfa, tre_tnfa_reach_t *reach, int num_tags)
-{
-  int i;
-
-  while (reach->state != NULL)
-    {
-      DPRINT((" %p", (void *)reach->state));
-      if (num_tags > 0)
-	{
-	  DPRINT(("/"));
-	  for (i = 0; i < num_tags; i++)
-	    {
-	      DPRINT(("%d:%d", i, reach->tags[i]));
-	      if (i < (num_tags-1))
-		DPRINT((","));
-	    }
-	}
-      reach++;
-    }
-  DPRINT(("\n"));
-
-}
-#endif /* TRE_DEBUG */
-
 static reg_errcode_t
-tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string, int len,
-		      int *match_tags, int eflags, int *match_end_ofs)
+tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string,
+		      int *match_tags, int eflags,
+		      int *match_end_ofs)
 {
   /* State variables required by GET_NEXT_WCHAR. */
   tre_char_t prev_c = 0, next_c = 0;
   const char *str_byte = string;
   int pos = -1;
-  int pos_add_next = 1;
+  unsigned int pos_add_next = 1;
 #ifdef TRE_MBSTATE
   mbstate_t mbstate;
 #endif /* TRE_MBSTATE */
@@ -210,14 +220,10 @@ tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string, int len,
       + (rbytes + xbytes * tnfa->num_states) * 2 + tbytes + pbytes;
 
     /* Allocate the memory. */
-#ifdef TRE_USE_ALLOCA
-    buf = alloca(total_bytes);
-#else /* !TRE_USE_ALLOCA */
-    buf = xmalloc(total_bytes);
-#endif /* !TRE_USE_ALLOCA */
+    buf = xmalloc((unsigned)total_bytes);
     if (buf == NULL)
       return REG_ESPACE;
-    memset(buf, 0, total_bytes);
+    memset(buf, 0, (size_t)total_bytes);
 
     /* Get the various pointers within tmp_buf (properly aligned). */
     tmp_tags = (void *)buf;
@@ -247,17 +253,12 @@ tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string, int len,
   GET_NEXT_WCHAR();
   pos = 0;
 
-  DPRINT(("length: %d\n", len));
-  DPRINT(("pos:chr/code | states and tags\n"));
-  DPRINT(("-------------+------------------------------------------------\n"));
-
   reach_next_i = reach_next;
   while (1)
     {
       /* If no match found yet, add the initial states to `reach_next'. */
       if (match_eo < 0)
 	{
-	  DPRINT((" init >"));
 	  trans_i = tnfa->initial;
 	  while (trans_i->state != NULL)
 	    {
@@ -266,12 +267,10 @@ tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string, int len,
 		  if (trans_i->assertions
 		      && CHECK_ASSERTIONS(trans_i->assertions))
 		    {
-		      DPRINT(("assertion failed\n"));
 		      trans_i++;
 		      continue;
 		    }
 
-		  DPRINT((" %p", (void *)trans_i->state));
 		  reach_next_i->state = trans_i->state;
 		  for (i = 0; i < num_tags; i++)
 		    reach_next_i->tags[i] = -1;
@@ -285,7 +284,6 @@ tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string, int len,
 		      }
 		  if (reach_next_i->state == tnfa->final)
 		    {
-		      DPRINT(("	 found empty match\n"));
 		      match_eo = pos;
 		      new_match = 1;
 		      for (i = 0; i < num_tags; i++)
@@ -297,7 +295,6 @@ tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string, int len,
 		}
 	      trans_i++;
 	    }
-	  DPRINT(("\n"));
 	  reach_next_i->state = NULL;
 	}
       else
@@ -312,18 +309,53 @@ tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string, int len,
 
       GET_NEXT_WCHAR();
 
-#ifdef TRE_DEBUG
-      DPRINT(("%3d:%2lc/%05d |", pos - 1, (tre_cint_t)prev_c, (int)prev_c));
-      tre_print_reach(tnfa, reach_next, num_tags);
-      DPRINT(("%3d:%2lc/%05d |", pos, (tre_cint_t)next_c, (int)next_c));
-      tre_print_reach(tnfa, reach_next, num_tags);
-#endif /* TRE_DEBUG */
-
       /* Swap `reach' and `reach_next'. */
       reach_i = reach;
       reach = reach_next;
       reach_next = reach_i;
 
+      /* For each state in `reach', weed out states that don't fulfill the
+	 minimal matching conditions. */
+      if (tnfa->num_minimals && new_match)
+	{
+	  new_match = 0;
+	  reach_next_i = reach_next;
+	  for (reach_i = reach; reach_i->state; reach_i++)
+	    {
+	      int skip = 0;
+	      for (i = 0; tnfa->minimal_tags[i] >= 0; i += 2)
+		{
+		  int end = tnfa->minimal_tags[i];
+		  int start = tnfa->minimal_tags[i + 1];
+		  if (end >= num_tags)
+		    {
+		      skip = 1;
+		      break;
+		    }
+		  else if (reach_i->tags[start] == match_tags[start]
+			   && reach_i->tags[end] < match_tags[end])
+		    {
+		      skip = 1;
+		      break;
+		    }
+		}
+	      if (!skip)
+		{
+		  reach_next_i->state = reach_i->state;
+		  tmp_iptr = reach_next_i->tags;
+		  reach_next_i->tags = reach_i->tags;
+		  reach_i->tags = tmp_iptr;
+		  reach_next_i++;
+		}
+	    }
+	  reach_next_i->state = NULL;
+
+	  /* Swap `reach' and `reach_next'. */
+	  reach_i = reach;
+	  reach = reach_next;
+	  reach_next = reach_i;
+	}
+
       /* For each state in `reach' see if there is a transition leaving with
 	 the current input symbol to a state not yet in `reach_next', and
 	 add the destination states to `reach_next'. */
@@ -333,28 +365,13 @@ tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string, int len,
 	  for (trans_i = reach_i->state; trans_i->state; trans_i++)
 	    {
 	      /* Does this transition match the input symbol? */
-	      if (trans_i->code_min <= prev_c &&
-		  trans_i->code_max >= prev_c)
+	      if (trans_i->code_min <= (tre_cint_t)prev_c &&
+		  trans_i->code_max >= (tre_cint_t)prev_c)
 		{
 		  if (trans_i->assertions
 		      && (CHECK_ASSERTIONS(trans_i->assertions)
-			  /* Handle character class transitions. */
-			  || ((trans_i->assertions & ASSERT_CHAR_CLASS)
-			      && !(tnfa->cflags & REG_ICASE)
-			      && !tre_isctype((tre_cint_t)prev_c,
-					      trans_i->u.class))
-			  || ((trans_i->assertions & ASSERT_CHAR_CLASS)
-			      && (tnfa->cflags & REG_ICASE)
-			      && (!tre_isctype(tre_tolower((tre_cint_t)prev_c),
-					       trans_i->u.class)
-				  && !tre_isctype(tre_toupper((tre_cint_t)prev_c),
-						  trans_i->u.class)))
-			  || ((trans_i->assertions & ASSERT_CHAR_CLASS_NEG)
-			      && tre_neg_char_classes_match(trans_i->neg_classes,
-							    (tre_cint_t)prev_c,
-							    tnfa->cflags & REG_ICASE))))
+			  || CHECK_CHAR_CLASSES(trans_i, tnfa, eflags)))
 		    {
-		      DPRINT(("assertion failed\n"));
 		      continue;
 		    }
 
@@ -385,7 +402,6 @@ tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string, int len,
 			      || (num_tags > 0
 				  && reach_next_i->tags[0] <= match_tags[0])))
 			{
-			  DPRINT(("  found match %p\n", trans_i->state));
 			  match_eo = pos;
 			  new_match = 1;
 			  for (i = 0; i < num_tags; i++)
@@ -409,7 +425,6 @@ tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string, int len,
 			  *reach_pos[trans_i->state_id].tags = tmp_tags;
 			  if (trans_i->state == tnfa->final)
 			    {
-			      DPRINT(("	 found better match\n"));
 			      match_eo = pos;
 			      new_match = 1;
 			      for (i = 0; i < num_tags; i++)
@@ -424,18 +439,15 @@ tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string, int len,
       reach_next_i->state = NULL;
     }
 
-  DPRINT(("match end offset = %d\n", match_eo));
-
-#ifndef TRE_USE_ALLOCA
   if (buf)
     xfree(buf);
-#endif /* !TRE_USE_ALLOCA */
 
   *match_end_ofs = match_eo;
   return match_eo >= 0 ? REG_OK : REG_NOMATCH;
 }
 
 
+
 /***********************************************************************
  from tre-match-backtrack.c
 ***********************************************************************/
@@ -489,16 +501,9 @@ typedef struct tre_backtrack_struct {
 #define BT_STACK_MBSTATE_OUT
 #endif /* !TRE_MBSTATE */
 
-
-#ifdef TRE_USE_ALLOCA
-#define tre_bt_mem_new		  tre_mem_newa
-#define tre_bt_mem_alloc	  tre_mem_alloca
-#define tre_bt_mem_destroy(obj)	  do { } while (0)
-#else /* !TRE_USE_ALLOCA */
 #define tre_bt_mem_new		  tre_mem_new
 #define tre_bt_mem_alloc	  tre_mem_alloc
 #define tre_bt_mem_destroy	  tre_mem_destroy
-#endif /* !TRE_USE_ALLOCA */
 
 
 #define BT_STACK_PUSH(_pos, _str_byte, _str_wide, _state, _state_id, _next_c, _tags, _mbstate) \
@@ -572,14 +577,13 @@ typedef struct tre_backtrack_struct {
 
 static reg_errcode_t
 tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
-		       int len, int *match_tags,
-		       int eflags, int *match_end_ofs)
+		       int *match_tags, int eflags, int *match_end_ofs)
 {
   /* State variables required by GET_NEXT_WCHAR. */
   tre_char_t prev_c = 0, next_c = 0;
   const char *str_byte = string;
   int pos = 0;
-  int pos_add_next = 1;
+  unsigned int pos_add_next = 1;
 #ifdef TRE_MBSTATE
   mbstate_t mbstate;
 #endif /* TRE_MBSTATE */
@@ -597,9 +601,6 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
   mbstate_t mbstate_start;
 #endif /* TRE_MBSTATE */
 
-  /* Compilation flags for this regexp. */
-  int cflags = tnfa->cflags;
-
   /* End offset of best match so far, or -1 if no match found yet. */
   int match_eo = -1;
   /* Tag arrays. */
@@ -633,30 +634,33 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
   stack->prev = NULL;
   stack->next = NULL;
 
-#ifdef TRE_USE_ALLOCA
-  tags = alloca(sizeof(*tags) * tnfa->num_tags);
-  pmatch = alloca(sizeof(*pmatch) * tnfa->num_submatches);
-  states_seen = alloca(sizeof(*states_seen) * tnfa->num_states);
-#else /* !TRE_USE_ALLOCA */
-  tags = xmalloc(sizeof(*tags) * tnfa->num_tags);
-  if (!tags)
+  if (tnfa->num_tags)
     {
-      ret = REG_ESPACE;
-      goto error_exit;
+      tags = xmalloc(sizeof(*tags) * tnfa->num_tags);
+      if (!tags)
+	{
+	  ret = REG_ESPACE;
+	  goto error_exit;
+	}
     }
-  pmatch = xmalloc(sizeof(*pmatch) * tnfa->num_submatches);
-  if (!pmatch)
+  if (tnfa->num_submatches)
     {
-      ret = REG_ESPACE;
-      goto error_exit;
+      pmatch = xmalloc(sizeof(*pmatch) * tnfa->num_submatches);
+      if (!pmatch)
+	{
+	  ret = REG_ESPACE;
+	  goto error_exit;
+	}
     }
-  states_seen = xmalloc(sizeof(*states_seen) * tnfa->num_states);
-  if (!states_seen)
+  if (tnfa->num_states)
     {
-      ret = REG_ESPACE;
-      goto error_exit;
+      states_seen = xmalloc(sizeof(*states_seen) * tnfa->num_states);
+      if (!states_seen)
+	{
+	  ret = REG_ESPACE;
+	  goto error_exit;
+	}
     }
-#endif /* !TRE_USE_ALLOCA */
 
  retry:
   {
@@ -685,10 +689,8 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
   next_tags = NULL;
   for (trans_i = tnfa->initial; trans_i->state; trans_i++)
     {
-      DPRINT(("> init %p, prev_c %lc\n", trans_i->state, (tre_cint_t)prev_c));
       if (trans_i->assertions && CHECK_ASSERTIONS(trans_i->assertions))
 	{
-	  DPRINT(("assert failed\n"));
 	  continue;
 	}
       if (state == NULL)
@@ -700,8 +702,7 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
       else
 	{
 	  /* Backtrack to this state. */
-	  DPRINT(("saving state %d for backtracking\n", trans_i->state_id));
-	  BT_STACK_PUSH(pos, str_byte, str_wide, trans_i->state,
+	  BT_STACK_PUSH(pos, str_byte, 0, trans_i->state,
 			trans_i->state_id, next_c, tags, mbstate);
 	  {
 	    int *tmp = trans_i->tags;
@@ -717,22 +718,16 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
       tags[*next_tags] = pos;
 
 
-  DPRINT(("entering match loop, pos %d, str_byte %p\n", pos, str_byte));
-  DPRINT(("pos:chr/code | state and tags\n"));
-  DPRINT(("-------------+------------------------------------------------\n"));
-
   if (state == NULL)
     goto backtrack;
 
   while (1)
     {
-      tre_tnfa_transition_t *trans_i, *next_state;
+      tre_tnfa_transition_t *next_state;
       int empty_br_match;
 
-      DPRINT(("start loop\n"));
       if (state == tnfa->final)
 	{
-	  DPRINT(("  match found, %d %d\n", match_eo, pos));
 	  if (match_eo < pos
 	      || (match_eo == pos
 		  && match_tags
@@ -741,7 +736,6 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
 	    {
 	      int i;
 	      /* This match wins the previous match. */
-	      DPRINT(("	 win previous\n"));
 	      match_eo = pos;
 	      if (match_tags)
 		for (i = 0; i < tnfa->num_tags; i++)
@@ -752,17 +746,6 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
 	  goto backtrack;
 	}
 
-#ifdef TRE_DEBUG
-      DPRINT(("%3d:%2lc/%05d | %p ", pos, (tre_cint_t)next_c, (int)next_c,
-	      state));
-      {
-	int i;
-	for (i = 0; i < tnfa->num_tags; i++)
-	  DPRINT(("%d%s", tags[i], i < tnfa->num_tags - 1 ? ", " : ""));
-	DPRINT(("\n"));
-      }
-#endif /* TRE_DEBUG */
-
       /* Go to the next character in the input string. */
       empty_br_match = 0;
       trans_i = state;
@@ -775,26 +758,17 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
 	  int bt_len;
 	  int result;
 
-	  DPRINT(("  should match back reference %d\n", bt));
 	  /* Get the substring we need to match against.  Remember to
 	     turn off REG_NOSUB temporarily. */
-	  tre_fill_pmatch(bt + 1, pmatch, tnfa->cflags & !REG_NOSUB,
+	  tre_fill_pmatch(bt + 1, pmatch, tnfa->cflags & ~REG_NOSUB,
 			  tnfa, tags, pos);
 	  so = pmatch[bt].rm_so;
 	  eo = pmatch[bt].rm_eo;
 	  bt_len = eo - so;
 
-	  if (len < 0)
-	    {
-	      result = strncmp((char*)string + so, str_byte - 1, bt_len);
-	    }
-	  else if (len - pos < bt_len)
-	    result = 1;
-	  else
-	    result = memcmp((char*)string + so, str_byte - 1, bt_len);
+	  result = strncmp((const char*)string + so, str_byte - 1,
+				 (size_t)bt_len);
 
-	  /* We can ignore multibyte characters here because the backref
-	     string is already aligned at character boundaries. */
 	  if (result == 0)
 	    {
 	      /* Back reference matched.  Check for infinite loop. */
@@ -802,7 +776,6 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
 		empty_br_match = 1;
 	      if (empty_br_match && states_seen[trans_i->state_id])
 		{
-		  DPRINT(("  avoid loop\n"));
 		  goto backtrack;
 		}
 
@@ -810,31 +783,20 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
 
 	      /* Advance in input string and resync `prev_c', `next_c'
 		 and pos. */
-	      DPRINT(("	 back reference matched\n"));
 	      str_byte += bt_len - 1;
 	      pos += bt_len - 1;
 	      GET_NEXT_WCHAR();
-	      DPRINT(("	 pos now %d\n", pos));
 	    }
 	  else
 	    {
-	      DPRINT(("	 back reference did not match\n"));
 	      goto backtrack;
 	    }
 	}
       else
 	{
 	  /* Check for end of string. */
-	  if (len < 0)
-	    {
-	      if (next_c == L'\0')
-		goto backtrack;
-	    }
-	  else
-	    {
-	      if (pos >= len)
+	  if (next_c == L'\0')
 		goto backtrack;
-	    }
 
 	  /* Read the next character. */
 	  GET_NEXT_WCHAR();
@@ -843,49 +805,29 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
       next_state = NULL;
       for (trans_i = state; trans_i->state; trans_i++)
 	{
-	  DPRINT(("  transition %d-%d (%c-%c) %d to %d\n",
-		  trans_i->code_min, trans_i->code_max,
-		  trans_i->code_min, trans_i->code_max,
-		  trans_i->assertions, trans_i->state_id));
-	  if (trans_i->code_min <= prev_c && trans_i->code_max >= prev_c)
+	  if (trans_i->code_min <= (tre_cint_t)prev_c
+	      && trans_i->code_max >= (tre_cint_t)prev_c)
 	    {
 	      if (trans_i->assertions
 		  && (CHECK_ASSERTIONS(trans_i->assertions)
-		      /* Handle character class transitions. */
-		      || ((trans_i->assertions & ASSERT_CHAR_CLASS)
-			  && !(cflags & REG_ICASE)
-			  && !tre_isctype((tre_cint_t)prev_c, trans_i->u.class))
-		      || ((trans_i->assertions & ASSERT_CHAR_CLASS)
-			  && (cflags & REG_ICASE)
-			  && (!tre_isctype(tre_tolower((tre_cint_t)prev_c),
-					   trans_i->u.class)
-			      && !tre_isctype(tre_toupper((tre_cint_t)prev_c),
-					      trans_i->u.class)))
-		      || ((trans_i->assertions & ASSERT_CHAR_CLASS_NEG)
-			  && tre_neg_char_classes_match(trans_i->neg_classes,
-							(tre_cint_t)prev_c,
-							cflags & REG_ICASE))))
+		      || CHECK_CHAR_CLASSES(trans_i, tnfa, eflags)))
 		{
-		  DPRINT(("  assertion failed\n"));
 		  continue;
 		}
 
 	      if (next_state == NULL)
 		{
 		  /* First matching transition. */
-		  DPRINT(("  Next state is %d\n", trans_i->state_id));
 		  next_state = trans_i->state;
 		  next_tags = trans_i->tags;
 		}
 	      else
 		{
-		  /* Second mathing transition.	 We may need to backtrack here
+		  /* Second matching transition.  We may need to backtrack here
 		     to take this transition instead of the first one, so we
 		     push this transition in the backtracking stack so we can
 		     jump back here if needed. */
-		  DPRINT(("  saving state %d for backtracking\n",
-			  trans_i->state_id));
-		  BT_STACK_PUSH(pos, str_byte, str_wide, trans_i->state,
+		  BT_STACK_PUSH(pos, str_byte, 0, trans_i->state,
 				trans_i->state_id, next_c, tags, mbstate);
 		  {
 		    int *tmp;
@@ -916,11 +858,8 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
 	  /* A matching transition was not found.  Try to backtrack. */
 	  if (stack->prev)
 	    {
-	      DPRINT(("	 backtracking\n"));
 	      if (stack->item.state->assertions & ASSERT_BACKREF)
 		{
-		  DPRINT(("  states_seen[%d] = 0\n",
-			  stack->item.state_id));
 		  states_seen[stack->item.state_id] = 0;
 		}
 
@@ -930,23 +869,10 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
 	    {
 	      /* Try starting from a later position in the input string. */
 	      /* Check for end of string. */
-	      if (len < 0)
-		{
-		  if (next_c == L'\0')
-		    {
-		      DPRINT(("end of string.\n"));
-		      break;
-		    }
-		}
-	      else
-		{
-		  if (pos >= len)
+	      if (next_c == L'\0')
 		    {
-		      DPRINT(("end of string.\n"));
 		      break;
 		    }
-		}
-	      DPRINT(("restarting from next start position\n"));
 	      next_c = next_c_start;
 #ifdef TRE_MBSTATE
 	      mbstate = mbstate_start;
@@ -956,7 +882,6 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
 	    }
 	  else
 	    {
-	      DPRINT(("finished\n"));
 	      break;
 	    }
 	}
@@ -979,7 +904,6 @@ tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
   return ret;
 }
 
-
 /***********************************************************************
  from regexec.c
 ***********************************************************************/
@@ -998,7 +922,6 @@ tre_fill_pmatch(size_t nmatch, regmatch_t pmatch[], int cflags,
   if (match_eo >= 0 && !(cflags & REG_NOSUB))
     {
       /* Construct submatch offsets from the tags. */
-      DPRINT(("end tag = t%d = %d\n", tnfa->end_tag, match_eo));
       submatch_data = tnfa->submatch_data;
       while (i < tnfa->num_submatches && i < nmatch)
 	{
@@ -1017,9 +940,6 @@ tre_fill_pmatch(size_t nmatch, regmatch_t pmatch[], int cflags,
 	  if (pmatch[i].rm_so == -1 || pmatch[i].rm_eo == -1)
 	    pmatch[i].rm_so = pmatch[i].rm_eo = -1;
 
-	  DPRINT(("pmatch[%d] = {t%d = %d, t%d = %d}\n", i,
-		  submatch_data[i].so_tag, pmatch[i].rm_so,
-		  submatch_data[i].eo_tag, pmatch[i].rm_eo));
 	  i++;
 	}
       /* Reset all submatches that are not within all of their parent
@@ -1035,7 +955,6 @@ tre_fill_pmatch(size_t nmatch, regmatch_t pmatch[], int cflags,
 	  if (parents != NULL)
 	    for (j = 0; parents[j] >= 0; j++)
 	      {
-		DPRINT(("pmatch[%d] parent %d\n", i, parents[j]));
 		if (pmatch[i].rm_so < pmatch[parents[j]].rm_so
 		    || pmatch[i].rm_eo > pmatch[parents[j]].rm_eo)
 		  pmatch[i].rm_so = pmatch[i].rm_eo = -1;
@@ -1057,19 +976,16 @@ tre_fill_pmatch(size_t nmatch, regmatch_t pmatch[], int cflags,
   Wrapper functions for POSIX compatible regexp matching.
 */
 
-static int
-tre_match(const tre_tnfa_t *tnfa, const void *string, size_t len,
+int
+regexec(const regex_t *preg, const char *string,
 	  size_t nmatch, regmatch_t pmatch[], int eflags)
 {
+  tre_tnfa_t *tnfa = (void *)preg->TRE_REGEX_T_FIELD;
   reg_errcode_t status;
   int *tags = NULL, eo;
   if (tnfa->num_tags > 0 && nmatch > 0)
     {
-#ifdef TRE_USE_ALLOCA
-      tags = alloca(sizeof(*tags) * tnfa->num_tags);
-#else /* !TRE_USE_ALLOCA */
       tags = xmalloc(sizeof(*tags) * tnfa->num_tags);
-#endif /* !TRE_USE_ALLOCA */
       if (tags == NULL)
 	return REG_ESPACE;
     }
@@ -1078,30 +994,18 @@ tre_match(const tre_tnfa_t *tnfa, const void *string, size_t len,
   if (tnfa->have_backrefs)
     {
       /* The regex has back references, use the backtracking matcher. */
-      status = tre_tnfa_run_backtrack(tnfa, string, len, tags, eflags, &eo);
+      status = tre_tnfa_run_backtrack(tnfa, string, tags, eflags, &eo);
     }
   else
     {
       /* Exact matching, no back references, use the parallel matcher. */
-      status = tre_tnfa_run_parallel(tnfa, string, len, tags, eflags, &eo);
+      status = tre_tnfa_run_parallel(tnfa, string, tags, eflags, &eo);
     }
 
   if (status == REG_OK)
     /* A match was found, so fill the submatch registers. */
     tre_fill_pmatch(nmatch, pmatch, tnfa->cflags, tnfa, tags, eo);
-#ifndef TRE_USE_ALLOCA
   if (tags)
     xfree(tags);
-#endif /* !TRE_USE_ALLOCA */
   return status;
 }
-
-int
-regexec(const regex_t *preg, const char *str,
-	size_t nmatch, regmatch_t pmatch[], int eflags)
-{
-  return tre_match((void *)preg->TRE_REGEX_T_FIELD, str, -1,
-                   nmatch, pmatch, eflags);
-}
-
-/* EOF */