--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/rx.c	Fri Dec 08 22:44:18 1995 +0000
@@ -0,0 +1,7188 @@
+/*	Copyright (C) 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
+
+This file is part of the librx library.
+
+Librx is free software; you can redistribute it and/or modify it under
+the terms of the GNU Library General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+Librx 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 General Public License
+for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with this software; see the file COPYING.LIB.  If not,
+write to the Free Software Foundation, 675 Mass Ave, Cambridge, MA
+02139, USA.  */
+
+/* NOTE!!!  AIX is so losing it requires this to be the first thing in the 
+ * file. 
+ * Do not put ANYTHING before it!  
+ */
+#if !defined (__GNUC__) && defined (_AIX)
+ #pragma alloca
+#endif
+
+/* To make linux happy? */
+#ifndef	_GNU_SOURCE
+#define	_GNU_SOURCE
+#endif
+
+#if HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+
+char rx_version_string[] = "GNU Rx version 0.07.1";
+
+			/* ``Too hard!''
+			 *	    -- anon.
+			 */
+
+
+#include <stdio.h>
+#include <ctype.h>
+#ifndef isgraph
+#define isgraph(c) (isprint (c) && !isspace (c))
+#endif
+#ifndef isblank
+#define isblank(c) ((c) == ' ' || (c) == '\t')
+#endif
+
+#include <sys/types.h>
+
+#undef MAX
+#undef MIN
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+typedef char boolean;
+#define false 0
+#define true 1
+
+#ifndef __GCC__
+#undef __inline__
+#define __inline__
+#endif
+
+/* Emacs already defines alloca, sometimes.  */
+#ifndef alloca
+
+/* Make alloca work the best possible way.  */
+#ifdef __GNUC__
+#define alloca __builtin_alloca
+#else /* not __GNUC__ */
+#if HAVE_ALLOCA_H
+#include <alloca.h>
+#else /* not __GNUC__ or HAVE_ALLOCA_H */
+#ifndef _AIX /* Already did AIX, up at the top.  */
+char *alloca ();
+#endif /* not _AIX */
+#endif /* not HAVE_ALLOCA_H */ 
+#endif /* not __GNUC__ */
+
+#endif /* not alloca */
+
+/* Memory management and stuff for emacs. */
+
+#define CHARBITS 8
+#define remalloc(M, S) (M ? realloc (M, S) : malloc (S))
+
+
+/* Should we use malloc or alloca?  If REGEX_MALLOC is not defined, we
+ * use `alloca' instead of `malloc' for the backtracking stack.
+ *
+ * Emacs will die miserably if we don't do this.
+ */
+
+#ifdef REGEX_MALLOC
+#define REGEX_ALLOCATE malloc
+#else /* not REGEX_MALLOC  */
+#define REGEX_ALLOCATE alloca
+#endif /* not REGEX_MALLOC */
+
+
+#ifdef RX_WANT_RX_DEFS
+#define RX_DECL extern
+#define RX_DEF_QUAL 
+#else
+#define RX_WANT_RX_DEFS
+#define RX_DECL static
+#define RX_DEF_QUAL static
+#endif
+#include "rx.h"
+#undef RX_DECL
+#define RX_DECL RX_DEF_QUAL
+
+
+#ifndef emacs
+
+#ifdef SYNTAX_TABLE
+extern char *re_syntax_table;
+#else /* not SYNTAX_TABLE */
+
+#ifdef __STDC__
+static void
+init_syntax_once (void)
+#else
+static void
+init_syntax_once ()
+#endif
+{
+   register int c;
+   static int done = 0;
+
+   if (done)
+     return;
+
+   bzero (re_syntax_table, sizeof re_syntax_table);
+
+   for (c = 'a'; c <= 'z'; c++)
+     re_syntax_table[c] = Sword;
+
+   for (c = 'A'; c <= 'Z'; c++)
+     re_syntax_table[c] = Sword;
+
+   for (c = '0'; c <= '9'; c++)
+     re_syntax_table[c] = Sword;
+
+   re_syntax_table['_'] = Sword;
+
+   done = 1;
+}
+#endif /* not SYNTAX_TABLE */
+#endif /* not emacs */
+
+/* Compile with `-DRX_DEBUG' and use the following flags.
+ *
+ * Debugging flags:
+ *   	rx_debug - print information as a regexp is compiled
+ * 	rx_debug_trace - print information as a regexp is executed
+ */
+
+#ifdef RX_DEBUG
+
+int rx_debug_compile = 0;
+int rx_debug_trace = 0;
+static struct re_pattern_buffer * dbug_rxb = 0;
+
+#ifdef __STDC__
+typedef void (*side_effect_printer) (struct rx *, void *, FILE *);
+#else
+typedef void (*side_effect_printer) ();
+#endif
+
+#ifdef __STDC__
+static void print_cset (struct rx *rx, rx_Bitset cset, FILE * fp);
+#else
+static void print_cset ();
+#endif
+
+#ifdef __STDC__
+static void
+print_rexp (struct rx *rx,
+	    struct rexp_node *node, int depth,
+	    side_effect_printer seprint, FILE * fp)
+#else
+static void
+print_rexp (rx, node, depth, seprint, fp)
+     struct rx *rx;
+     struct rexp_node *node;
+     int depth;
+     side_effect_printer seprint;
+     FILE * fp;
+#endif
+{
+  if (!node)
+    return;
+  else
+    {
+      switch (node->type)
+	{
+	case r_cset:
+	  {
+	    fprintf (fp, "%*s", depth, "");
+	    print_cset (rx, node->params.cset, fp);
+	    fputc ('\n', fp);
+	    break;
+	  }
+
+ 	case r_opt:
+	case r_star:
+	  fprintf (fp, "%*s%s\n", depth, "",
+		   node->type == r_opt ? "opt" : "star");
+	  print_rexp (rx, node->params.pair.left, depth + 3, seprint, fp);
+	  break;
+
+	case r_2phase_star:
+	  fprintf (fp, "%*s2phase star\n", depth, "");
+	  print_rexp (rx, node->params.pair.right, depth + 3, seprint, fp);
+	  print_rexp (rx, node->params.pair.left, depth + 3, seprint, fp);
+	  break;
+
+
+	case r_alternate:
+	case r_concat:
+	  fprintf (fp, "%*s%s\n", depth, "",
+		   node->type == r_alternate ? "alt" : "concat");
+	  print_rexp (rx, node->params.pair.left, depth + 3, seprint, fp);
+	  print_rexp (rx, node->params.pair.right, depth + 3, seprint, fp);
+	  break;
+	case r_side_effect:
+	  fprintf (fp, "%*sSide effect: ", depth, "");
+	  seprint (rx, node->params.side_effect, fp);
+	  fputc ('\n', fp);
+	}
+    }
+}
+
+#ifdef __STDC__
+static void
+print_nfa (struct rx * rx,
+	   struct rx_nfa_state * n,
+	   side_effect_printer seprint, FILE * fp)
+#else
+static void
+print_nfa (rx, n, seprint, fp)
+     struct rx * rx;
+     struct rx_nfa_state * n;
+     side_effect_printer seprint;
+     FILE * fp;
+#endif
+{
+  while (n)
+    {
+      struct rx_nfa_edge *e = n->edges;
+      struct rx_possible_future *ec = n->futures;
+      fprintf (fp, "node %d %s\n", n->id,
+	       n->is_final ? "final" : (n->is_start ? "start" : ""));
+      while (e)
+	{
+	  fprintf (fp, "   edge to %d, ", e->dest->id);
+	  switch (e->type)
+	    {
+	    case ne_epsilon:
+	      fprintf (fp, "epsilon\n");
+	      break;
+	    case ne_side_effect:
+	      fprintf (fp, "side effect ");
+	      seprint (rx, e->params.side_effect, fp);
+	      fputc ('\n', fp);
+	      break;
+	    case ne_cset:
+	      fprintf (fp, "cset ");
+	      print_cset (rx, e->params.cset, fp);
+	      fputc ('\n', fp);
+	      break;
+	    }
+	  e = e->next;
+	}
+
+      while (ec)
+	{
+	  int x;
+	  struct rx_nfa_state_set * s;
+	  struct rx_se_list * l;
+	  fprintf (fp, "   eclosure to {");
+	  for (s = ec->destset; s; s = s->cdr)
+	    fprintf (fp, "%d ", s->car->id);
+	  fprintf (fp, "} (");
+	  for (l = ec->effects; l; l = l->cdr)
+	    {
+	      seprint (rx, l->car, fp);
+	      fputc (' ', fp);
+	    }
+	  fprintf (fp, ")\n");
+	  ec = ec->next;
+	}
+      n = n->next;
+    }
+}
+
+static char * efnames [] =
+{
+  "bogon",
+  "re_se_try",
+  "re_se_pushback",
+  "re_se_push0",
+  "re_se_pushpos",
+  "re_se_chkpos",
+  "re_se_poppos",
+  "re_se_at_dot",
+  "re_se_syntax",
+  "re_se_not_syntax",
+  "re_se_begbuf",
+  "re_se_hat",
+  "re_se_wordbeg",
+  "re_se_wordbound",
+  "re_se_notwordbound",
+  "re_se_wordend",
+  "re_se_endbuf",
+  "re_se_dollar",
+  "re_se_fail",
+};
+
+static char * efnames2[] =
+{
+  "re_se_win",
+  "re_se_lparen",
+  "re_se_rparen",
+  "re_se_backref",
+  "re_se_iter",
+  "re_se_end_iter",
+  "re_se_tv"
+};
+
+static char * inx_names[] = 
+{
+  "rx_backtrack_point",
+  "rx_do_side_effects",
+  "rx_cache_miss",
+  "rx_next_char",
+  "rx_backtrack",
+  "rx_error_inx",
+  "rx_num_instructions"
+};
+
+
+#ifdef __STDC__
+static void
+re_seprint (struct rx * rx, void * effect, FILE * fp)
+#else
+static void
+re_seprint (rx, effect, fp)
+     struct rx * rx;
+     void * effect;
+     FILE * fp;
+#endif
+{
+  if ((int)effect < 0)
+    fputs (efnames[-(int)effect], fp);
+  else if (dbug_rxb)
+    {
+      struct re_se_params * p = &dbug_rxb->se_params[(int)effect];
+      fprintf (fp, "%s(%d,%d)", efnames2[p->se], p->op1, p->op2);
+    }
+  else
+    fprintf (fp, "[complex op # %d]", (int)effect);
+}
+
+
+/* These are so the regex.c regression tests will compile. */
+void
+print_compiled_pattern (rxb)
+     struct re_pattern_buffer * rxb;
+{
+}
+
+void
+print_fastmap (fm)
+     char * fm;
+{
+}
+
+#endif /* RX_DEBUG */
+
+
+
+/* This page: Bitsets.  Completely unintersting. */
+
+#ifdef __STDC__
+RX_DECL int
+rx_bitset_is_equal (int size, rx_Bitset a, rx_Bitset b)
+#else
+RX_DECL int
+rx_bitset_is_equal (size, a, b)
+     int size;
+     rx_Bitset a;
+     rx_Bitset b;
+#endif
+{
+  int x;
+  RX_subset s = b[0];
+  b[0] = ~a[0];
+
+  for (x = rx_bitset_numb_subsets(size) - 1; a[x] == b[x]; --x)
+    ;
+
+  b[0] = s;
+  return !x && s == a[0];
+}
+
+#ifdef __STDC__
+RX_DECL int
+rx_bitset_is_subset (int size, rx_Bitset a, rx_Bitset b)
+#else
+RX_DECL int
+rx_bitset_is_subset (size, a, b)
+     int size;
+     rx_Bitset a;
+     rx_Bitset b;
+#endif
+{
+  int x = rx_bitset_numb_subsets(size) - 1;
+  while (x-- && (a[x] & b[x]) == a[x]);
+  return x == -1;
+}
+
+
+#ifdef __STDC__
+RX_DECL int
+rx_bitset_empty (int size, rx_Bitset set)
+#else
+RX_DECL int
+rx_bitset_empty (size, set)
+     int size;
+     rx_Bitset set;
+#endif
+{
+  int x;
+  RX_subset s = set[0];
+  set[0] = 1;
+  for (x = rx_bitset_numb_subsets(size) - 1; !set[x]; --x)
+    ;
+  set[0] = s;
+  return !s;
+}
+
+#ifdef __STDC__
+RX_DECL void
+rx_bitset_null (int size, rx_Bitset b)
+#else
+RX_DECL void
+rx_bitset_null (size, b)
+     int size;
+     rx_Bitset b;
+#endif
+{
+  bzero (b, rx_sizeof_bitset(size));
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_bitset_universe (int size, rx_Bitset b)
+#else
+RX_DECL void
+rx_bitset_universe (size, b)
+     int size;
+     rx_Bitset b;
+#endif
+{
+  int x = rx_bitset_numb_subsets (size);
+  while (x--)
+    *b++ = ~(RX_subset)0;
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_bitset_complement (int size, rx_Bitset b)
+#else
+RX_DECL void
+rx_bitset_complement (size, b)
+     int size;
+     rx_Bitset b;
+#endif
+{
+  int x = rx_bitset_numb_subsets (size);
+  while (x--)
+    {
+      *b = ~*b;
+      ++b;
+    }
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_bitset_assign (int size, rx_Bitset a, rx_Bitset b)
+#else
+RX_DECL void
+rx_bitset_assign (size, a, b)
+     int size;
+     rx_Bitset a;
+     rx_Bitset b;
+#endif
+{
+  int x;
+  for (x = rx_bitset_numb_subsets(size) - 1; x >=0; --x)
+    a[x] = b[x];
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_bitset_union (int size, rx_Bitset a, rx_Bitset b)
+#else
+RX_DECL void
+rx_bitset_union (size, a, b)
+     int size;
+     rx_Bitset a;
+     rx_Bitset b;
+#endif
+{
+  int x;
+  for (x = rx_bitset_numb_subsets(size) - 1; x >=0; --x)
+    a[x] |= b[x];
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_bitset_intersection (int size,
+			rx_Bitset a, rx_Bitset b)
+#else
+RX_DECL void
+rx_bitset_intersection (size, a, b)
+     int size;
+     rx_Bitset a;
+     rx_Bitset b;
+#endif
+{
+  int x;
+  for (x = rx_bitset_numb_subsets(size) - 1; x >=0; --x)
+    a[x] &= b[x];
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_bitset_difference (int size, rx_Bitset a, rx_Bitset b)
+#else
+RX_DECL void
+rx_bitset_difference (size, a, b)
+     int size;
+     rx_Bitset a;
+     rx_Bitset b;
+#endif
+{
+  int x;
+  for (x = rx_bitset_numb_subsets(size) - 1; x >=0; --x)
+    a[x] &=  ~ b[x];
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_bitset_revdifference (int size,
+			 rx_Bitset a, rx_Bitset b)
+#else
+RX_DECL void
+rx_bitset_revdifference (size, a, b)
+     int size;
+     rx_Bitset a;
+     rx_Bitset b;
+#endif
+{
+  int x;
+  for (x = rx_bitset_numb_subsets(size) - 1; x >=0; --x)
+    a[x] = ~a[x] & b[x];
+}
+
+#ifdef __STDC__
+RX_DECL void
+rx_bitset_xor (int size, rx_Bitset a, rx_Bitset b)
+#else
+RX_DECL void
+rx_bitset_xor (size, a, b)
+     int size;
+     rx_Bitset a;
+     rx_Bitset b;
+#endif
+{
+  int x;
+  for (x = rx_bitset_numb_subsets(size) - 1; x >=0; --x)
+    a[x] ^= b[x];
+}
+
+
+#ifdef __STDC__
+RX_DECL unsigned long
+rx_bitset_hash (int size, rx_Bitset b)
+#else
+RX_DECL unsigned long
+rx_bitset_hash (size, b)
+     int size;
+     rx_Bitset b;
+#endif
+{
+  int x;
+  unsigned long hash = (unsigned long)rx_bitset_hash;
+
+  for (x = rx_bitset_numb_subsets(size) - 1; x >= 0; --x)
+    hash ^= rx_bitset_subset_val(b, x);
+
+  return hash;
+}
+
+
+RX_DECL RX_subset rx_subset_singletons [RX_subset_bits] = 
+{
+  0x1,
+  0x2,
+  0x4,
+  0x8,
+  0x10,
+  0x20,
+  0x40,
+  0x80,
+  0x100,
+  0x200,
+  0x400,
+  0x800,
+  0x1000,
+  0x2000,
+  0x4000,
+  0x8000,
+  0x10000,
+  0x20000,
+  0x40000,
+  0x80000,
+  0x100000,
+  0x200000,
+  0x400000,
+  0x800000,
+  0x1000000,
+  0x2000000,
+  0x4000000,
+  0x8000000,
+  0x10000000,
+  0x20000000,
+  0x40000000,
+  0x80000000
+};
+
+#ifdef RX_DEBUG
+
+#ifdef __STDC__
+static void
+print_cset (struct rx *rx, rx_Bitset cset, FILE * fp)
+#else
+static void
+print_cset (rx, cset, fp)
+     struct rx *rx;
+     rx_Bitset cset;
+     FILE * fp;
+#endif
+{
+  int x;
+  fputc ('[', fp);
+  for (x = 0; x < rx->local_cset_size; ++x)
+    if (RX_bitset_member (cset, x))
+      {
+	if (isprint(x))
+	  fputc (x, fp);
+	else
+	  fprintf (fp, "\\0%o ", x);
+      }
+  fputc (']', fp);
+}
+
+#endif /*  RX_DEBUG */
+
+
+
+static unsigned long rx_hash_masks[4] =
+{
+  0x12488421,
+  0x96699669,
+  0xbe7dd7eb,
+  0xffffffff
+};
+
+
+/* Hash tables */
+#ifdef __STDC__
+RX_DECL struct rx_hash_item * 
+rx_hash_find (struct rx_hash * table,
+	      unsigned long hash,
+	      void * value,
+	      struct rx_hash_rules * rules)
+#else
+RX_DECL struct rx_hash_item * 
+rx_hash_find (table, hash, value, rules)
+     struct rx_hash * table;
+     unsigned long hash;
+     void * value;
+     struct rx_hash_rules * rules;
+#endif
+{
+  rx_hash_eq eq = rules->eq;
+  int maskc = 0;
+  long mask = rx_hash_masks [0];
+  int bucket = (hash & mask) % 13;
+
+  while (table->children [bucket])
+    {
+      table = table->children [bucket];
+      ++maskc;
+      mask = rx_hash_masks[maskc];
+      bucket = (hash & mask) % 13;
+    }
+
+  {
+    struct rx_hash_item * it = table->buckets[bucket];
+    while (it)
+      if (eq (it->data, value))
+	return it;
+      else
+	it = it->next_same_hash;
+  }
+
+  return 0;
+}
+
+
+#ifdef __STDC__
+RX_DECL struct rx_hash_item *
+rx_hash_store (struct rx_hash * table,
+	       unsigned long hash,
+	       void * value,
+	       struct rx_hash_rules * rules)
+#else
+RX_DECL struct rx_hash_item *
+rx_hash_store (table, hash, value, rules)
+     struct rx_hash * table;
+     unsigned long hash;
+     void * value;
+     struct rx_hash_rules * rules;
+#endif
+{
+  rx_hash_eq eq = rules->eq;
+  int maskc = 0;
+  long mask = rx_hash_masks[0];
+  int bucket = (hash & mask) % 13;
+  int depth = 0;
+  
+  while (table->children [bucket])
+    {
+      table = table->children [bucket];
+      ++maskc;
+      mask = rx_hash_masks[maskc];
+      bucket = (hash & mask) % 13;
+      ++depth;
+    }
+  
+  {
+    struct rx_hash_item * it = table->buckets[bucket];
+    while (it)
+      if (eq (it->data, value))
+	return it;
+      else
+	it = it->next_same_hash;
+  }
+  
+  {
+    if (   (depth < 3)
+	&& (table->bucket_size [bucket] >= 4))
+      {
+	struct rx_hash * newtab = ((struct rx_hash *)
+				   rules->hash_alloc (rules));
+	if (!newtab)
+	  goto add_to_bucket;
+	bzero (newtab, sizeof (*newtab));
+	newtab->parent = table;
+	{
+	  struct rx_hash_item * them = table->buckets[bucket];
+	  unsigned long newmask = rx_hash_masks[maskc + 1];
+	  while (them)
+	    {
+	      struct rx_hash_item * save = them->next_same_hash;
+	      int new_buck = (them->hash & newmask) % 13;
+	      them->next_same_hash = newtab->buckets[new_buck];
+	      newtab->buckets[new_buck] = them;
+	      them->table = newtab;
+	      them = save;
+	      ++newtab->bucket_size[new_buck];
+	      ++newtab->refs;
+	    }
+	  table->refs = (table->refs - table->bucket_size[bucket] + 1);
+	  table->bucket_size[bucket] = 0;
+	  table->buckets[bucket] = 0;
+	  table->children[bucket] = newtab;
+	  table = newtab;
+	  bucket = (hash & newmask) % 13;
+	}
+      }
+  }
+ add_to_bucket:
+  {
+    struct rx_hash_item  * it = ((struct rx_hash_item *)
+				 rules->hash_item_alloc (rules, value));
+    if (!it)
+      return 0;
+    it->hash = hash;
+    it->table = table;
+    /* DATA and BINDING are to be set in hash_item_alloc */
+    it->next_same_hash = table->buckets [bucket];
+    table->buckets[bucket] = it;
+    ++table->bucket_size [bucket];
+    ++table->refs;
+    return it;
+  }
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_hash_free (struct rx_hash_item * it, struct rx_hash_rules * rules)
+#else
+RX_DECL void
+rx_hash_free (it, rules)
+     struct rx_hash_item * it;
+     struct rx_hash_rules * rules;
+#endif
+{
+  if (it)
+    {
+      struct rx_hash * table = it->table;
+      unsigned long hash = it->hash;
+      int depth = (table->parent
+		   ? (table->parent->parent
+		      ? (table->parent->parent->parent
+			 ? 3
+			 : 2)
+		      : 1)
+		   : 0);
+      int bucket = (hash & rx_hash_masks [depth]) % 13;
+      struct rx_hash_item ** pos = &table->buckets [bucket];
+      
+      while (*pos != it)
+	pos = &(*pos)->next_same_hash;
+      *pos = it->next_same_hash;
+      rules->free_hash_item (it, rules);
+      --table->bucket_size[bucket];
+      --table->refs;
+      while (!table->refs && depth)
+	{
+	  struct rx_hash * save = table;
+	  table = table->parent;
+	  --depth;
+	  bucket = (hash & rx_hash_masks [depth]) % 13;
+	  --table->refs;
+	  table->children[bucket] = 0;
+	  rules->free_hash (save, rules);
+	}
+    }
+}
+
+#ifdef __STDC__
+RX_DECL void
+rx_free_hash_table (struct rx_hash * tab, rx_hash_freefn freefn,
+		    struct rx_hash_rules * rules)
+#else
+RX_DECL void
+rx_free_hash_table (tab, freefn, rules)
+     struct rx_hash * tab;
+     rx_hash_freefn freefn;
+     struct rx_hash_rules * rules;
+#endif
+{
+  int x;
+
+  for (x = 0; x < 13; ++x)
+    if (tab->children[x])
+      {
+	rx_free_hash_table (tab->children[x], freefn, rules);
+	rules->free_hash (tab->children[x], rules);
+      }
+    else
+      {
+	struct rx_hash_item * them = tab->buckets[x];
+	while (them)
+	  {
+	    struct rx_hash_item * that = them;
+	    them = that->next_same_hash;
+	    freefn (that);
+	    rules->free_hash_item (that, rules);
+	  }
+      }
+}
+
+
+
+/* Utilities for manipulating bitset represntations of characters sets. */
+
+#ifdef __STDC__
+RX_DECL rx_Bitset
+rx_cset (struct rx *rx)
+#else
+RX_DECL rx_Bitset
+rx_cset (rx)
+     struct rx *rx;
+#endif
+{
+  rx_Bitset b = (rx_Bitset) malloc (rx_sizeof_bitset (rx->local_cset_size));
+  if (b)
+    rx_bitset_null (rx->local_cset_size, b);
+  return b;
+}
+
+
+#ifdef __STDC__
+RX_DECL rx_Bitset
+rx_copy_cset (struct rx *rx, rx_Bitset a)
+#else
+RX_DECL rx_Bitset
+rx_copy_cset (rx, a)
+     struct rx *rx;
+     rx_Bitset a;
+#endif
+{
+  rx_Bitset cs = rx_cset (rx);
+
+  if (cs)
+    rx_bitset_union (rx->local_cset_size, cs, a);
+
+  return cs;
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_free_cset (struct rx * rx, rx_Bitset c)
+#else
+RX_DECL void
+rx_free_cset (rx, c)
+     struct rx * rx;
+     rx_Bitset c;
+#endif
+{
+  if (c)
+    free ((char *)c);
+}
+
+
+/* Hash table memory allocation policy for the regexp compiler */
+
+#ifdef __STDC__
+static struct rx_hash *
+compiler_hash_alloc (struct rx_hash_rules * rules)
+#else
+static struct rx_hash *
+compiler_hash_alloc (rules)
+     struct rx_hash_rules * rules;
+#endif
+{
+  return (struct rx_hash *)malloc (sizeof (struct rx_hash));
+}
+
+
+#ifdef __STDC__
+static struct rx_hash_item *
+compiler_hash_item_alloc (struct rx_hash_rules * rules, void * value)
+#else
+static struct rx_hash_item *
+compiler_hash_item_alloc (rules, value)
+     struct rx_hash_rules * rules;
+     void * value;
+#endif
+{
+  struct rx_hash_item * it;
+  it = (struct rx_hash_item *)malloc (sizeof (*it));
+  if (it)
+    {
+      it->data = value;
+      it->binding = 0;
+    }
+  return it;
+}
+
+
+#ifdef __STDC__
+static void
+compiler_free_hash (struct rx_hash * tab,
+		    struct rx_hash_rules * rules)
+#else
+static void
+compiler_free_hash (tab, rules)
+     struct rx_hash * tab;
+     struct rx_hash_rules * rules;
+#endif
+{
+  free ((char *)tab);
+}
+
+
+#ifdef __STDC__
+static void
+compiler_free_hash_item (struct rx_hash_item * item,
+			 struct rx_hash_rules * rules)
+#else
+static void
+compiler_free_hash_item (item, rules)
+     struct rx_hash_item * item;
+     struct rx_hash_rules * rules;
+#endif
+{
+  free ((char *)item);
+}
+
+
+/* This page: REXP_NODE (expression tree) structures. */
+
+#ifdef __STDC__
+RX_DECL struct rexp_node *
+rexp_node (struct rx *rx,
+	   enum rexp_node_type type)
+#else
+RX_DECL struct rexp_node *
+rexp_node (rx, type)
+     struct rx *rx;
+     enum rexp_node_type type;
+#endif
+{
+  struct rexp_node *n;
+
+  n = (struct rexp_node *)malloc (sizeof (*n));
+  bzero (n, sizeof (*n));
+  if (n)
+    n->type = type;
+  return n;
+}
+
+
+/* free_rexp_node assumes that the bitset passed to rx_mk_r_cset
+ * can be freed using rx_free_cset.
+ */
+#ifdef __STDC__
+RX_DECL struct rexp_node *
+rx_mk_r_cset (struct rx * rx,
+	      rx_Bitset b)
+#else
+RX_DECL struct rexp_node *
+rx_mk_r_cset (rx, b)
+     struct rx * rx;
+     rx_Bitset b;
+#endif
+{
+  struct rexp_node * n = rexp_node (rx, r_cset);
+  if (n)
+    n->params.cset = b;
+  return n;
+}
+
+
+#ifdef __STDC__
+RX_DECL struct rexp_node *
+rx_mk_r_concat (struct rx * rx,
+		struct rexp_node * a,
+		struct rexp_node * b)
+#else
+RX_DECL struct rexp_node *
+rx_mk_r_concat (rx, a, b)
+     struct rx * rx;
+     struct rexp_node * a;
+     struct rexp_node * b;
+#endif
+{
+  struct rexp_node * n = rexp_node (rx, r_concat);
+  if (n)
+    {
+      n->params.pair.left = a;
+      n->params.pair.right = b;
+    }
+  return n;
+}
+
+
+#ifdef __STDC__
+RX_DECL struct rexp_node *
+rx_mk_r_alternate (struct rx * rx,
+		   struct rexp_node * a,
+		   struct rexp_node * b)
+#else
+RX_DECL struct rexp_node *
+rx_mk_r_alternate (rx, a, b)
+     struct rx * rx;
+     struct rexp_node * a;
+     struct rexp_node * b;
+#endif
+{
+  struct rexp_node * n = rexp_node (rx, r_alternate);
+  if (n)
+    {
+      n->params.pair.left = a;
+      n->params.pair.right = b;
+    }
+  return n;
+}
+
+
+#ifdef __STDC__
+RX_DECL struct rexp_node *
+rx_mk_r_opt (struct rx * rx,
+	     struct rexp_node * a)
+#else
+RX_DECL struct rexp_node *
+rx_mk_r_opt (rx, a)
+     struct rx * rx;
+     struct rexp_node * a;
+#endif
+{
+  struct rexp_node * n = rexp_node (rx, r_opt);
+  if (n)
+    {
+      n->params.pair.left = a;
+      n->params.pair.right = 0;
+    }
+  return n;
+}
+
+
+#ifdef __STDC__
+RX_DECL struct rexp_node *
+rx_mk_r_star (struct rx * rx,
+	      struct rexp_node * a)
+#else
+RX_DECL struct rexp_node *
+rx_mk_r_star (rx, a)
+     struct rx * rx;
+     struct rexp_node * a;
+#endif
+{
+  struct rexp_node * n = rexp_node (rx, r_star);
+  if (n)
+    {
+      n->params.pair.left = a;
+      n->params.pair.right = 0;
+    }
+  return n;
+}
+
+
+#ifdef __STDC__
+RX_DECL struct rexp_node *
+rx_mk_r_2phase_star (struct rx * rx,
+		     struct rexp_node * a,
+		     struct rexp_node * b)
+#else
+RX_DECL struct rexp_node *
+rx_mk_r_2phase_star (rx, a, b)
+     struct rx * rx;
+     struct rexp_node * a;
+     struct rexp_node * b;
+#endif
+{
+  struct rexp_node * n = rexp_node (rx, r_2phase_star);
+  if (n)
+    {
+      n->params.pair.left = a;
+      n->params.pair.right = b;
+    }
+  return n;
+}
+
+
+#ifdef __STDC__
+RX_DECL struct rexp_node *
+rx_mk_r_side_effect (struct rx * rx,
+		     rx_side_effect a)
+#else
+RX_DECL struct rexp_node *
+rx_mk_r_side_effect (rx, a)
+     struct rx * rx;
+     rx_side_effect a;
+#endif
+{
+  struct rexp_node * n = rexp_node (rx, r_side_effect);
+  if (n)
+    {
+      n->params.side_effect = a;
+      n->params.pair.right = 0;
+    }
+  return n;
+}
+
+
+#ifdef __STDC__
+RX_DECL struct rexp_node *
+rx_mk_r_data  (struct rx * rx,
+	       void * a)
+#else
+RX_DECL struct rexp_node *
+rx_mk_r_data  (rx, a)
+     struct rx * rx;
+     void * a;
+#endif
+{
+  struct rexp_node * n = rexp_node (rx, r_data);
+  if (n)
+    {
+      n->params.pair.left = a;
+      n->params.pair.right = 0;
+    }
+  return n;
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_free_rexp (struct rx * rx, struct rexp_node * node)
+#else
+RX_DECL void
+rx_free_rexp (rx, node)
+     struct rx * rx;
+     struct rexp_node * node;
+#endif
+{
+  if (node)
+    {
+      switch (node->type)
+	{
+	case r_cset:
+	  if (node->params.cset)
+	    rx_free_cset (rx, node->params.cset);
+
+	case r_side_effect:
+	  break;
+	  
+	case r_concat:
+	case r_alternate:
+	case r_2phase_star:
+	case r_opt:
+	case r_star:
+	  rx_free_rexp (rx, node->params.pair.left);
+	  rx_free_rexp (rx, node->params.pair.right);
+	  break;
+
+	case r_data:
+	  /* This shouldn't occur. */
+	  break;
+	}
+      free ((char *)node);
+    }
+}
+
+
+#ifdef __STDC__
+RX_DECL struct rexp_node * 
+rx_copy_rexp (struct rx *rx,
+	   struct rexp_node *node)
+#else
+RX_DECL struct rexp_node * 
+rx_copy_rexp (rx, node)
+     struct rx *rx;
+     struct rexp_node *node;
+#endif
+{
+  if (!node)
+    return 0;
+  else
+    {
+      struct rexp_node *n = rexp_node (rx, node->type);
+      if (!n)
+	return 0;
+      switch (node->type)
+	{
+	case r_cset:
+	  n->params.cset = rx_copy_cset (rx, node->params.cset);
+	  if (!n->params.cset)
+	    {
+	      rx_free_rexp (rx, n);
+	      return 0;
+	    }
+	  break;
+
+	case r_side_effect:
+	  n->params.side_effect = node->params.side_effect;
+	  break;
+
+	case r_concat:
+	case r_alternate:
+	case r_opt:
+	case r_2phase_star:
+	case r_star:
+	  n->params.pair.left =
+	    rx_copy_rexp (rx, node->params.pair.left);
+	  n->params.pair.right =
+	    rx_copy_rexp (rx, node->params.pair.right);
+	  if (   (node->params.pair.left && !n->params.pair.left)
+	      || (node->params.pair.right && !n->params.pair.right))
+	    {
+	      rx_free_rexp  (rx, n);
+	      return 0;
+	    }
+	  break;
+	case r_data:
+	  /* shouldn't happen */
+	  break;
+	}
+      return n;
+    }
+}
+
+
+
+/* This page: functions to build and destroy graphs that describe nfa's */
+
+/* Constructs a new nfa node. */
+#ifdef __STDC__
+RX_DECL struct rx_nfa_state *
+rx_nfa_state (struct rx *rx)
+#else
+RX_DECL struct rx_nfa_state *
+rx_nfa_state (rx)
+     struct rx *rx;
+#endif
+{
+  struct rx_nfa_state * n = (struct rx_nfa_state *)malloc (sizeof (*n));
+  if (!n)
+    return 0;
+  bzero (n, sizeof (*n));
+  n->next = rx->nfa_states;
+  rx->nfa_states = n;
+  return n;
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_free_nfa_state (struct rx_nfa_state * n)
+#else
+RX_DECL void
+rx_free_nfa_state (n)
+  struct rx_nfa_state * n;
+#endif
+{
+  free ((char *)n);
+}
+
+
+/* This looks up an nfa node, given a numeric id.  Numeric id's are
+ * assigned after the nfa has been built.
+ */
+#ifdef __STDC__
+RX_DECL struct rx_nfa_state * 
+rx_id_to_nfa_state (struct rx * rx,
+		    int id)
+#else
+RX_DECL struct rx_nfa_state * 
+rx_id_to_nfa_state (rx, id)
+     struct rx * rx;
+     int id;
+#endif
+{
+  struct rx_nfa_state * n;
+  for (n = rx->nfa_states; n; n = n->next)
+    if (n->id == id)
+      return n;
+  return 0;
+}
+
+
+/* This adds an edge between two nodes, but doesn't initialize the 
+ * edge label.
+ */
+
+#ifdef __STDC__
+RX_DECL struct rx_nfa_edge * 
+rx_nfa_edge (struct rx *rx,
+	     enum rx_nfa_etype type,
+	     struct rx_nfa_state *start,
+	     struct rx_nfa_state *dest)
+#else
+RX_DECL struct rx_nfa_edge * 
+rx_nfa_edge (rx, type, start, dest)
+     struct rx *rx;
+     enum rx_nfa_etype type;
+     struct rx_nfa_state *start;
+     struct rx_nfa_state *dest;
+#endif
+{
+  struct rx_nfa_edge *e;
+  e = (struct rx_nfa_edge *)malloc (sizeof (*e));
+  if (!e)
+    return 0;
+  e->next = start->edges;
+  start->edges = e;
+  e->type = type;
+  e->dest = dest;
+  return e;
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_free_nfa_edge (struct rx_nfa_edge * e)
+#else
+RX_DECL void
+rx_free_nfa_edge (e)
+     struct rx_nfa_edge * e;
+#endif
+{
+  free ((char *)e);
+}
+
+
+/* This constructs a POSSIBLE_FUTURE, which is a kind epsilon-closure
+ * of an NFA.  These are added to an nfa automaticly by eclose_nfa.
+ */  
+
+#ifdef __STDC__
+static struct rx_possible_future * 
+rx_possible_future (struct rx * rx,
+		 struct rx_se_list * effects)
+#else
+static struct rx_possible_future * 
+rx_possible_future (rx, effects)
+     struct rx * rx;
+     struct rx_se_list * effects;
+#endif
+{
+  struct rx_possible_future *ec;
+  ec = (struct rx_possible_future *) malloc (sizeof (*ec));
+  if (!ec)
+    return 0;
+  ec->destset = 0;
+  ec->next = 0;
+  ec->effects = effects;
+  return ec;
+}
+
+
+#ifdef __STDC__
+static void
+rx_free_possible_future (struct rx_possible_future * pf)
+#else
+static void
+rx_free_possible_future (pf)
+     struct rx_possible_future * pf;
+#endif
+{
+  free ((char *)pf);
+}
+
+
+#ifdef __STDC__
+RX_DECL void
+rx_free_nfa (struct rx *rx)
+#else
+RX_DECL void
+rx_free_nfa (rx)
+     struct rx *rx;
+#endif
+{
+  while (rx->nfa_states)
+    {
+      while (rx->nfa_states->edges)
+	{
+	  switch (rx->nfa_states->edges->type)
+	    {
+	    case ne_cset:
+	      rx_free_cset (rx, rx->nfa_states->edges->params.cset);
+	      break;
+	    default:
+	      break;
+	    }
+	  {
+	    struct rx_nfa_edge * e;
+	    e = rx->nfa_states->edges;
+	    rx->nfa_states->edges = rx->nfa_states->edges->next;
+	    rx_free_nfa_edge (e);
+	  }
+	} /* while (rx->nfa_states->edges) */
+      {
+	/* Iterate over the partial epsilon closures of rx->nfa_states */
+	struct rx_possible_future * pf = rx->nfa_states->futures;
+	while (pf)
+	  {
+	    struct rx_possible_future * pft = pf;
+	    pf = pf->next;
+	    rx_free_possible_future (pft);
+	  }
+      }
+      {
+	struct rx_nfa_state *n;
+	n = rx->nfa_states;
+	rx->nfa_states = rx->nfa_states->next;
+	rx_free_nfa_state (n);
+      }
+    }
+}
+
+
+
+/* This page: translating a pattern expression into an nfa and doing the 
+ * static part of the nfa->super-nfa translation.
+ */
+
+/* This is the thompson regexp->nfa algorithm. 
+ * It is modified to allow for `side-effect epsilons.'  Those are
+ * edges that are taken whenever a similar epsilon edge would be,
+ * but which imply that some side effect occurs when the edge 
+ * is taken.
+ *
+ * Side effects are used to model parts of the pattern langauge 
+ * that are not regular (in the formal sense).
+ */
+
+#ifdef __STDC__
+RX_DECL int
+rx_build_nfa (struct rx *rx,
+	      struct rexp_node *rexp,
+	      struct rx_nfa_state **start,
+	      struct rx_nfa_state **end)
+#else
+RX_DECL int
+rx_build_nfa (rx, rexp, start, end)
+     struct rx *rx;
+     struct rexp_node *rexp;
+     struct rx_nfa_state **start;
+     struct rx_nfa_state **end;
+#endif
+{
+  struct rx_nfa_edge *edge;
+
+  /* Start & end nodes may have been allocated by the caller. */
+  *start = *start ? *start : rx_nfa_state (rx);
+
+  if (!*start)
+    return 0;
+
+  if (!rexp)
+    {
+      *end = *start;
+      return 1;
+    }
+
+  *end = *end ? *end : rx_nfa_state (rx);
+
+  if (!*end)
+    {
+      rx_free_nfa_state (*start);
+      return 0;
+    }
+
+  switch (rexp->type)
+    {
+    case r_data:
+      return 0;
+
+    case r_cset:
+      edge = rx_nfa_edge (rx, ne_cset, *start, *end);
+      if (!edge)
+	return 0;
+      edge->params.cset = rx_copy_cset (rx, rexp->params.cset);
+      if (!edge->params.cset)
+	{
+	  rx_free_nfa_edge (edge);
+	  return 0;
+	}
+      return 1;
+ 
+    case r_opt:
+      return (rx_build_nfa (rx, rexp->params.pair.left, start, end)
+	      && rx_nfa_edge (rx, ne_epsilon, *start, *end));
+
+    case r_star:
+      {
+	struct rx_nfa_state * star_start = 0;
+	struct rx_nfa_state * star_end = 0;
+	return (rx_build_nfa (rx, rexp->params.pair.left,
+			      &star_start, &star_end)
+		&& star_start
+		&& star_end
+		&& rx_nfa_edge (rx, ne_epsilon, star_start, star_end)
+		&& rx_nfa_edge (rx, ne_epsilon, *start, star_start)
+		&& rx_nfa_edge (rx, ne_epsilon, star_end, *end)
+
+		&& rx_nfa_edge (rx, ne_epsilon, star_end, star_start));
+      }
+
+    case r_2phase_star:
+      {
+	struct rx_nfa_state * star_start = 0;
+	struct rx_nfa_state * star_end = 0;
+	struct rx_nfa_state * loop_exp_start = 0;
+	struct rx_nfa_state * loop_exp_end = 0;
+
+	return (rx_build_nfa (rx, rexp->params.pair.left,
+			      &star_start, &star_end)
+		&& rx_build_nfa (rx, rexp->params.pair.right,
+				 &loop_exp_start, &loop_exp_end)
+		&& star_start
+		&& star_end
+		&& loop_exp_end
+		&& loop_exp_start
+		&& rx_nfa_edge (rx, ne_epsilon, star_start, *end)
+		&& rx_nfa_edge (rx, ne_epsilon, *start, star_start)
+		&& rx_nfa_edge (rx, ne_epsilon, star_end, *end)
+
+		&& rx_nfa_edge (rx, ne_epsilon, star_end, loop_exp_start)
+		&& rx_nfa_edge (rx, ne_epsilon, loop_exp_end, star_start));
+      }
+
+
+    case r_concat:
+      {
+	struct rx_nfa_state *shared = 0;
+	return
+	  (rx_build_nfa (rx, rexp->params.pair.left, start, &shared)
+	   && rx_build_nfa (rx, rexp->params.pair.right, &shared, end));
+      }
+
+    case r_alternate:
+      {
+	struct rx_nfa_state *ls = 0;
+	struct rx_nfa_state *le = 0;
+	struct rx_nfa_state *rs = 0;
+	struct rx_nfa_state *re = 0;
+	return (rx_build_nfa (rx, rexp->params.pair.left, &ls, &le)
+		&& rx_build_nfa (rx, rexp->params.pair.right, &rs, &re)
+		&& rx_nfa_edge (rx, ne_epsilon, *start, ls)
+		&& rx_nfa_edge (rx, ne_epsilon, *start, rs)
+		&& rx_nfa_edge (rx, ne_epsilon, le, *end)
+		&& rx_nfa_edge (rx, ne_epsilon, re, *end));
+      }
+
+    case r_side_effect:
+      edge = rx_nfa_edge (rx, ne_side_effect, *start, *end);
+      if (!edge)
+	return 0;
+      edge->params.side_effect = rexp->params.side_effect;
+      return 1;
+    }
+
+  /* this should never happen */
+  return 0;
+}
+
+
+/* RX_NAME_NFA_STATES identifies all nodes with outgoing non-epsilon
+ * transitions.  Only these nodes can occur in super-states.  
+ * All nodes are given an integer id. 
+ * The id is non-negative if the node has non-epsilon out-transitions, negative
+ * otherwise (this is because we want the non-negative ids to be used as 
+ * array indexes in a few places).
+ */
+
+#ifdef __STDC__
+RX_DECL void
+rx_name_nfa_states (struct rx *rx)
+#else
+RX_DECL void
+rx_name_nfa_states (rx)
+     struct rx *rx;
+#endif
+{
+  struct rx_nfa_state *n = rx->nfa_states;
+
+  rx->nodec = 0;
+  rx->epsnodec = -1;
+
+  while (n)
+    {
+      struct rx_nfa_edge *e = n->edges;
+
+      if (n->is_start)
+	n->eclosure_needed = 1;
+
+      while (e)
+	{
+	  switch (e->type)
+	    {
+	    case ne_epsilon:
+	    case ne_side_effect:
+	      break;
+
+	    case ne_cset:
+	      n->id = rx->nodec++;
+	      {
+		struct rx_nfa_edge *from_n = n->edges;
+		while (from_n)
+		  {
+		    from_n->dest->eclosure_needed = 1;
+		    from_n = from_n->next;
+		  }
+	      }
+	      goto cont;
+	    }
+	  e = e->next;
+	}
+      n->id = rx->epsnodec--;
+    cont:
+      n = n->next;
+    }
+  rx->epsnodec = -rx->epsnodec;
+}
+
+
+/* This page: data structures for the static part of the nfa->supernfa
+ * translation.
+ *
+ * There are side effect lists -- lists of side effects occuring
+ * along an uninterrupted, acyclic path of side-effect epsilon edges.
+ * Such paths are collapsed to single edges in the course of computing
+ * epsilon closures.  Such single edges are labled with a list of all
+ * the side effects entailed in crossing them.  Like lists of side
+ * effects are made == by the constructors below.
+ *
+ * There are also nfa state sets.  These are used to hold a list of all
+ * states reachable from a starting state for a given type of transition
+ * and side effect list.   These are also hash-consed.
+ */
+
+/* The next several functions compare, construct, etc. lists of side
+ * effects.  See ECLOSE_NFA (below) for details.
+ */
+
+/* Ordering of rx_se_list
+ * (-1, 0, 1 return value convention).
+ */
+
+#ifdef __STDC__
+static int 
+se_list_cmp (void * va, void * vb)
+#else
+static int 
+se_list_cmp (va, vb)
+     void * va;
+     void * vb;
+#endif
+{
+  struct rx_se_list * a = (struct rx_se_list *)va;
+  struct rx_se_list * b = (struct rx_se_list *)vb;
+
+  return ((va == vb)
+	  ? 0
+	  : (!va
+	     ? -1
+	     : (!vb
+		? 1
+		: ((long)a->car < (long)b->car
+		   ? 1
+		   : ((long)a->car > (long)b->car
+		      ? -1
+		      : se_list_cmp ((void *)a->cdr, (void *)b->cdr))))));
+}
+
+
+#ifdef __STDC__
+static int 
+se_list_equal (void * va, void * vb)
+#else
+static int 
+se_list_equal (va, vb)
+     void * va;
+     void * vb;
+#endif
+{
+  return !(se_list_cmp (va, vb));
+}
+
+static struct rx_hash_rules se_list_hash_rules =
+{
+  se_list_equal,
+  compiler_hash_alloc,
+  compiler_free_hash,
+  compiler_hash_item_alloc,
+  compiler_free_hash_item
+};
+
+
+#ifdef __STDC__
+static struct rx_se_list * 
+side_effect_cons (struct rx * rx,
+		  void * se, struct rx_se_list * list)
+#else
+static struct rx_se_list * 
+side_effect_cons (rx, se, list)
+     struct rx * rx;
+     void * se;
+     struct rx_se_list * list;
+#endif
+{
+  struct rx_se_list * l;
+  l = ((struct rx_se_list *) malloc (sizeof (*l)));
+  if (!l)
+    return 0;
+  l->car = se;
+  l->cdr = list;
+  return l;
+}
+
+
+#ifdef __STDC__
+static struct rx_se_list *
+hash_cons_se_prog (struct rx * rx,
+		   struct rx_hash * memo,
+		   void * car, struct rx_se_list * cdr)
+#else
+static struct rx_se_list *
+hash_cons_se_prog (rx, memo, car, cdr)
+     struct rx * rx;
+     struct rx_hash * memo;
+     void * car;
+     struct rx_se_list * cdr;
+#endif
+{
+  long hash = (long)car ^ (long)cdr;
+  struct rx_se_list template;
+
+  template.car = car;
+  template.cdr = cdr;
+  {
+    struct rx_hash_item * it = rx_hash_store (memo, hash,
+					      (void *)&template,
+					      &se_list_hash_rules);
+    if (!it)
+      return 0;
+    if (it->data == (void *)&template)
+      {
+	struct rx_se_list * consed;
+	consed = (struct rx_se_list *) malloc (sizeof (*consed));
+	*consed = template;
+	it->data = (void *)consed;
+      }
+    return (struct rx_se_list *)it->data;
+  }
+}
+     
+
+#ifdef __STDC__
+static struct rx_se_list *
+hash_se_prog (struct rx * rx, struct rx_hash * memo, struct rx_se_list * prog)
+#else
+static struct rx_se_list *
+hash_se_prog (rx, memo, prog)
+     struct rx * rx;
+     struct rx_hash * memo;
+     struct rx_se_list * prog;
+#endif
+{
+  struct rx_se_list * answer = 0;
+  while (prog)
+    {
+      answer = hash_cons_se_prog (rx, memo, prog->car, answer);
+      if (!answer)
+	return 0;
+      prog = prog->cdr;
+    }
+  return answer;
+}
+
+#ifdef __STDC__
+static int 
+nfa_set_cmp (void * va, void * vb)
+#else
+static int 
+nfa_set_cmp (va, vb)
+     void * va;
+     void * vb;
+#endif
+{
+  struct rx_nfa_state_set * a = (struct rx_nfa_state_set *)va;
+  struct rx_nfa_state_set * b = (struct rx_nfa_state_set *)vb;
+
+  return ((va == vb)
+	  ? 0
+	  : (!va
+	     ? -1
+	     : (!vb
+		? 1
+		: (a->car->id < b->car->id
+		   ? 1
+		   : (a->car->id > b->car->id
+		      ? -1
+		      : nfa_set_cmp ((void *)a->cdr, (void *)b->cdr))))));
+}
+
+#ifdef __STDC__
+static int 
+nfa_set_equal (void * va, void * vb)
+#else
+static int 
+nfa_set_equal (va, vb)
+     void * va;
+     void * vb;
+#endif
+{
+  return !nfa_set_cmp (va, vb);
+}
+
+static struct rx_hash_rules nfa_set_hash_rules =
+{
+  nfa_set_equal,
+  compiler_hash_alloc,
+  compiler_free_hash,
+  compiler_hash_item_alloc,
+  compiler_free_hash_item
+};
+
+
+#ifdef __STDC__
+static struct rx_nfa_state_set * 
+nfa_set_cons (struct rx * rx,
+	      struct rx_hash * memo, struct rx_nfa_state * state,
+	      struct rx_nfa_state_set * set)
+#else
+static struct rx_nfa_state_set * 
+nfa_set_cons (rx, memo, state, set)
+     struct rx * rx;
+     struct rx_hash * memo;
+     struct rx_nfa_state * state;
+     struct rx_nfa_state_set * set;
+#endif
+{
+  struct rx_nfa_state_set template;
+  struct rx_hash_item * node;
+  template.car = state;
+  template.cdr = set;
+  node = rx_hash_store (memo,
+			(((long)state) >> 8) ^ (long)set,
+			&template, &nfa_set_hash_rules);
+  if (!node)
+    return 0;
+  if (node->data == &template)
+    {
+      struct rx_nfa_state_set * l;
+      l = (struct rx_nfa_state_set *) malloc (sizeof (*l));
+      node->data = (void *) l;
+      if (!l)
+	return 0;
+      *l = template;
+    }
+  return (struct rx_nfa_state_set *)node->data;
+}
+
+
+#ifdef __STDC__
+static struct rx_nfa_state_set * 
+nfa_set_enjoin (struct rx * rx,
+		struct rx_hash * memo, struct rx_nfa_state * state,
+		struct rx_nfa_state_set * set)
+#else
+static struct rx_nfa_state_set * 
+nfa_set_enjoin (rx, memo, state, set)
+     struct rx * rx;
+     struct rx_hash * memo;
+     struct rx_nfa_state * state;
+     struct rx_nfa_state_set * set;
+#endif
+{
+  if (!set || state->id < set->car->id)
+    return nfa_set_cons (rx, memo, state, set);
+  if (state->id == set->car->id)
+    return set;
+  else
+    {
+      struct rx_nfa_state_set * newcdr
+	= nfa_set_enjoin (rx, memo, state, set->cdr);
+      if (newcdr != set->cdr)
+	set = nfa_set_cons (rx, memo, set->car, newcdr);
+      return set;
+    }
+}
+
+
+
+/* This page: computing epsilon closures.  The closures aren't total.
+ * Each node's closures are partitioned according to the side effects entailed
+ * along the epsilon edges.  Return true on success.
+ */ 
+
+struct eclose_frame
+{
+  struct rx_se_list *prog_backwards;
+};
+
+
+#ifdef __STDC__
+static int 
+eclose_node (struct rx *rx, struct rx_nfa_state *outnode,
+	     struct rx_nfa_state *node, struct eclose_frame *frame)
+#else
+static int 
+eclose_node (rx, outnode, node, frame)
+     struct rx *rx;
+     struct rx_nfa_state *outnode;
+     struct rx_nfa_state *node;
+     struct eclose_frame *frame;
+#endif
+{
+  struct rx_nfa_edge *e = node->edges;
+
+  /* For each node, we follow all epsilon paths to build the closure.
+   * The closure omits nodes that have only epsilon edges.
+   * The closure is split into partial closures -- all the states in
+   * a partial closure are reached by crossing the same list of
+   * of side effects (though not necessarily the same path).
+   */
+  if (node->mark)
+    return 1;
+  node->mark = 1;
+
+  if (node->id >= 0 || node->is_final)
+    {
+      struct rx_possible_future **ec;
+      struct rx_se_list * prog_in_order
+	= ((struct rx_se_list *)hash_se_prog (rx,
+					      &rx->se_list_memo,
+					      frame->prog_backwards));
+      int cmp;
+
+      ec = &outnode->futures;
+
+      while (*ec)
+	{
+	  cmp = se_list_cmp ((void *)(*ec)->effects, (void *)prog_in_order);
+	  if (cmp <= 0)
+	    break;
+	  ec = &(*ec)->next;
+	}
+      if (!*ec || (cmp < 0))
+	{
+	  struct rx_possible_future * saved = *ec;
+	  *ec = rx_possible_future (rx, prog_in_order);
+	  (*ec)->next = saved;
+	  if (!*ec)
+	    return 0;
+	}
+      if (node->id >= 0)
+	{
+	  (*ec)->destset = nfa_set_enjoin (rx, &rx->set_list_memo,
+					   node, (*ec)->destset);
+	  if (!(*ec)->destset)
+	    return 0;
+	}
+    }
+
+  while (e)
+    {
+      switch (e->type)
+	{
+	case ne_epsilon:
+	  if (!eclose_node (rx, outnode, e->dest, frame))
+	    return 0;
+	  break;
+	case ne_side_effect:
+	  {
+	    frame->prog_backwards = side_effect_cons (rx, 
+						      e->params.side_effect,
+						      frame->prog_backwards);
+	    if (!frame->prog_backwards)
+	      return 0;
+	    if (!eclose_node (rx, outnode, e->dest, frame))
+	      return 0;
+	    {
+	      struct rx_se_list * dying = frame->prog_backwards;
+	      frame->prog_backwards = frame->prog_backwards->cdr;
+	      free ((char *)dying);
+	    }
+	    break;
+	  }
+	default:
+	  break;
+	}
+      e = e->next;
+    }
+  node->mark = 0;
+  return 1;
+}
+
+
+#ifdef __STDC__
+RX_DECL int 
+rx_eclose_nfa (struct rx *rx)
+#else
+RX_DECL int 
+rx_eclose_nfa (rx)
+     struct rx *rx;
+#endif
+{
+  struct rx_nfa_state *n = rx->nfa_states;
+  struct eclose_frame frame;
+  static int rx_id = 0;
+  
+  frame.prog_backwards = 0;
+  rx->rx_id = rx_id++;
+  bzero (&rx->se_list_memo, sizeof (rx->se_list_memo));
+  bzero (&rx->set_list_memo, sizeof (rx->set_list_memo));
+  while (n)
+    {
+      n->futures = 0;
+      if (n->eclosure_needed && !eclose_node (rx, n, n, &frame))
+	return 0;
+      /* clear_marks (rx); */
+      n = n->next;
+    }
+  return 1;
+}
+
+
+/* This deletes epsilon edges from an NFA.  After running eclose_node,
+ * we have no more need for these edges.  They are removed to simplify
+ * further operations on the NFA.
+ */
+
+#ifdef __STDC__
+RX_DECL void 
+rx_delete_epsilon_transitions (struct rx *rx)
+#else
+RX_DECL void 
+rx_delete_epsilon_transitions (rx)
+     struct rx *rx;
+#endif
+{
+  struct rx_nfa_state *n = rx->nfa_states;
+  struct rx_nfa_edge **e;
+
+  while (n)
+    {
+      e = &n->edges;
+      while (*e)
+	{
+	  struct rx_nfa_edge *t;
+	  switch ((*e)->type)
+	    {
+	    case ne_epsilon:
+	    case ne_side_effect:
+	      t = *e;
+	      *e = t->next;
+	      rx_free_nfa_edge (t);
+	      break;
+
+	    default:
+	      e = &(*e)->next;
+	      break;
+	    }
+	}
+      n = n->next;
+    }
+}
+
+
+/* This page: storing the nfa in a contiguous region of memory for
+ * subsequent conversion to a super-nfa.
+ */
+
+/* This is for qsort on an array of nfa_states. The order
+ * is based on state ids and goes 
+ *		[0...MAX][MIN..-1] where (MAX>=0) and (MIN<0)
+ * This way, positive ids double as array indices.
+ */
+
+#ifdef __STDC__
+static int 
+nfacmp (void * va, void * vb)
+#else
+static int 
+nfacmp (va, vb)
+     void * va;
+     void * vb;
+#endif
+{
+  struct rx_nfa_state **a = (struct rx_nfa_state **)va;
+  struct rx_nfa_state **b = (struct rx_nfa_state **)vb;
+  return (*a == *b		/* &&&& 3.18 */
+	  ? 0
+	  : (((*a)->id < 0) == ((*b)->id < 0)
+	     ? (((*a)->id  < (*b)->id) ? -1 : 1)
+	     : (((*a)->id < 0)
+		? 1 : -1)));
+}
+
+#ifdef __STDC__
+static int 
+count_hash_nodes (struct rx_hash * st)
+#else
+static int 
+count_hash_nodes (st)
+     struct rx_hash * st;
+#endif
+{
+  int x;
+  int count = 0;
+  for (x = 0; x < 13; ++x)
+    count += ((st->children[x])
+	      ? count_hash_nodes (st->children[x])
+	      : st->bucket_size[x]);
+  
+  return count;
+}
+
+
+#ifdef __STDC__
+static void 
+se_memo_freer (struct rx_hash_item * node)
+#else
+static void 
+se_memo_freer (node)
+     struct rx_hash_item * node;
+#endif
+{
+  free ((char *)node->data);
+}
+
+
+#ifdef __STDC__
+static void 
+nfa_set_freer (struct rx_hash_item * node)
+#else
+static void 
+nfa_set_freer (node)
+     struct rx_hash_item * node;
+#endif
+{
+  free ((char *)node->data);
+}
+
+
+/* This copies an entire NFA into a single malloced block of memory.
+ * Mostly this is for compatability with regex.c, though it is convenient
+ * to have the nfa nodes in an array.
+ */
+
+#ifdef __STDC__
+RX_DECL int 
+rx_compactify_nfa (struct rx *rx,
+		   void **mem, unsigned long *size)
+#else
+RX_DECL int 
+rx_compactify_nfa (rx, mem, size)
+     struct rx *rx;
+     void **mem;
+     unsigned long *size;
+#endif
+{
+  int total_nodec;
+  struct rx_nfa_state *n;
+  int edgec = 0;
+  int eclosec = 0;
+  int se_list_consc = count_hash_nodes (&rx->se_list_memo);
+  int nfa_setc = count_hash_nodes (&rx->set_list_memo);
+  unsigned long total_size;
+
+  /* This takes place in two stages.   First, the total size of the
+   * nfa is computed, then structures are copied.  
+   */   
+  n = rx->nfa_states;
+  total_nodec = 0;
+  while (n)
+    {
+      struct rx_nfa_edge *e = n->edges;
+      struct rx_possible_future *ec = n->futures;
+      ++total_nodec;
+      while (e)
+	{
+	  ++edgec;
+	  e = e->next;
+	}
+      while (ec)
+	{
+	  ++eclosec;
+	  ec = ec->next;
+	}
+      n = n->next;
+    }
+
+  total_size = (total_nodec * sizeof (struct rx_nfa_state)
+		+ edgec * rx_sizeof_bitset (rx->local_cset_size)
+		+ edgec * sizeof (struct rx_nfa_edge)
+		+ nfa_setc * sizeof (struct rx_nfa_state_set)
+		+ eclosec * sizeof (struct rx_possible_future)
+		+ se_list_consc * sizeof (struct rx_se_list)
+		+ rx->reserved);
+
+  if (total_size > *size)
+    {
+      *mem = remalloc (*mem, total_size);
+      if (*mem)
+	*size = total_size;
+      else
+	return 0;
+    }
+  /* Now we've allocated the memory; this copies the NFA. */
+  {
+    static struct rx_nfa_state **scratch = 0;
+    static int scratch_alloc = 0;
+    struct rx_nfa_state *state_base = (struct rx_nfa_state *) * mem;
+    struct rx_nfa_state *new_state = state_base;
+    struct rx_nfa_edge *new_edge =
+      (struct rx_nfa_edge *)
+	((char *) state_base + total_nodec * sizeof (struct rx_nfa_state));
+    struct rx_se_list * new_se_list =
+      (struct rx_se_list *)
+	((char *)new_edge + edgec * sizeof (struct rx_nfa_edge));
+    struct rx_possible_future *new_close =
+      ((struct rx_possible_future *)
+       ((char *) new_se_list
+	+ se_list_consc * sizeof (struct rx_se_list)));
+    struct rx_nfa_state_set * new_nfa_set =
+      ((struct rx_nfa_state_set *)
+       ((char *)new_close + eclosec * sizeof (struct rx_possible_future)));
+    char *new_bitset =
+      ((char *) new_nfa_set + nfa_setc * sizeof (struct rx_nfa_state_set));
+    int x;
+    struct rx_nfa_state *n;
+
+    if (scratch_alloc < total_nodec)
+      {
+	scratch = ((struct rx_nfa_state **)
+		   remalloc (scratch, total_nodec * sizeof (*scratch)));
+	if (scratch)
+	  scratch_alloc = total_nodec;
+	else
+	  {
+	    scratch_alloc = 0;
+	    return 0;
+	  }
+      }
+
+    for (x = 0, n = rx->nfa_states; n; n = n->next)
+      scratch[x++] = n;
+
+    qsort (scratch, total_nodec,
+	   sizeof (struct rx_nfa_state *), (int (*)())nfacmp);
+
+    for (x = 0; x < total_nodec; ++x)
+      {
+	struct rx_possible_future *eclose = scratch[x]->futures;
+	struct rx_nfa_edge *edge = scratch[x]->edges;
+	struct rx_nfa_state *cn = new_state++;
+	cn->futures = 0;
+	cn->edges = 0;
+	cn->next = (x == total_nodec - 1) ? 0 : (cn + 1);
+	cn->id = scratch[x]->id;
+	cn->is_final = scratch[x]->is_final;
+	cn->is_start = scratch[x]->is_start;
+	cn->mark = 0;
+	while (edge)
+	  {
+	    int indx = (edge->dest->id < 0
+			 ? (total_nodec + edge->dest->id)
+			 : edge->dest->id);
+	    struct rx_nfa_edge *e = new_edge++;
+	    rx_Bitset cset = (rx_Bitset) new_bitset;
+	    new_bitset += rx_sizeof_bitset (rx->local_cset_size);
+	    rx_bitset_null (rx->local_cset_size, cset);
+	    rx_bitset_union (rx->local_cset_size, cset, edge->params.cset);
+	    e->next = cn->edges;
+	    cn->edges = e;
+	    e->type = edge->type;
+	    e->dest = state_base + indx;
+	    e->params.cset = cset;
+	    edge = edge->next;
+	  }
+	while (eclose)
+	  {
+	    struct rx_possible_future *ec = new_close++;
+	    struct rx_hash_item * sp;
+	    struct rx_se_list ** sepos;
+	    struct rx_se_list * sesrc;
+	    struct rx_nfa_state_set * destlst;
+	    struct rx_nfa_state_set ** destpos;
+	    ec->next = cn->futures;
+	    cn->futures = ec;
+	    for (sepos = &ec->effects, sesrc = eclose->effects;
+		 sesrc;
+		 sesrc = sesrc->cdr, sepos = &(*sepos)->cdr)
+	      {
+		sp = rx_hash_find (&rx->se_list_memo,
+				   (long)sesrc->car ^ (long)sesrc->cdr,
+				   sesrc, &se_list_hash_rules);
+		if (sp->binding)
+		  {
+		    sesrc = (struct rx_se_list *)sp->binding;
+		    break;
+		  }
+		*new_se_list = *sesrc;
+		sp->binding = (void *)new_se_list;
+		*sepos = new_se_list;
+		++new_se_list;
+	      }
+	    *sepos = sesrc;
+	    for (destpos = &ec->destset, destlst = eclose->destset;
+		 destlst;
+		 destpos = &(*destpos)->cdr, destlst = destlst->cdr)
+	      {
+		sp = rx_hash_find (&rx->set_list_memo,
+				   ((((long)destlst->car) >> 8)
+				    ^ (long)destlst->cdr),
+				   destlst, &nfa_set_hash_rules);
+		if (sp->binding)
+		  {
+		    destlst = (struct rx_nfa_state_set *)sp->binding;
+		    break;
+		  }
+		*new_nfa_set = *destlst;
+		new_nfa_set->car = state_base + destlst->car->id;
+		sp->binding = (void *)new_nfa_set;
+		*destpos = new_nfa_set;
+		++new_nfa_set;
+	      }
+	    *destpos = destlst;
+	    eclose = eclose->next;
+	  }
+      }
+  }
+  rx_free_hash_table (&rx->se_list_memo, se_memo_freer, &se_list_hash_rules);
+  bzero (&rx->se_list_memo, sizeof (rx->se_list_memo));
+  rx_free_hash_table (&rx->set_list_memo, nfa_set_freer, &nfa_set_hash_rules);
+  bzero (&rx->set_list_memo, sizeof (rx->set_list_memo));
+
+  rx_free_nfa (rx);
+  rx->nfa_states = (struct rx_nfa_state *)*mem;
+  return 1;
+}
+
+
+/* The functions in the next several pages define the lazy-NFA-conversion used
+ * by matchers.  The input to this construction is an NFA such as 
+ * is built by compactify_nfa (rx.c).  The output is the superNFA.
+ */
+
+/* Match engines can use arbitrary values for opcodes.  So, the parse tree 
+ * is built using instructions names (enum rx_opcode), but the superstate
+ * nfa is populated with mystery opcodes (void *).
+ *
+ * For convenience, here is an id table.  The opcodes are == to their inxs
+ *
+ * The lables in re_search_2 would make good values for instructions.
+ */
+
+void * rx_id_instruction_table[rx_num_instructions] =
+{
+  (void *) rx_backtrack_point,
+  (void *) rx_do_side_effects,
+  (void *) rx_cache_miss,
+  (void *) rx_next_char,
+  (void *) rx_backtrack,
+  (void *) rx_error_inx
+};
+
+
+
+/* Memory mgt. for superstate graphs. */
+
+#ifdef __STDC__
+static char *
+rx_cache_malloc (struct rx_cache * cache, int bytes)
+#else
+static char *
+rx_cache_malloc (cache, bytes)
+     struct rx_cache * cache;
+     int bytes;
+#endif
+{
+  while (cache->bytes_left < bytes)
+    {
+      if (cache->memory_pos)
+	cache->memory_pos = cache->memory_pos->next;
+      if (!cache->memory_pos)
+	{
+	  cache->morecore (cache);
+	  if (!cache->memory_pos)
+	    return 0;
+	}
+      cache->bytes_left = cache->memory_pos->bytes;
+      cache->memory_addr = ((char *)cache->memory_pos
+			    + sizeof (struct rx_blocklist));
+    }
+  cache->bytes_left -= bytes;
+  {
+    char * addr = cache->memory_addr;
+    cache->memory_addr += bytes;
+    return addr;
+  }
+}
+
+#ifdef __STDC__
+static void
+rx_cache_free (struct rx_cache * cache,
+	       struct rx_freelist ** freelist, char * mem)
+#else
+static void
+rx_cache_free (cache, freelist, mem)
+     struct rx_cache * cache;
+     struct rx_freelist ** freelist;
+     char * mem;
+#endif
+{
+  struct rx_freelist * it = (struct rx_freelist *)mem;
+  it->next = *freelist;
+  *freelist = it;
+}
+
+
+/* The partially instantiated superstate graph has a transition 
+ * table at every node.  There is one entry for every character.
+ * This fills in the transition for a set.
+ */
+#ifdef __STDC__
+static void 
+install_transition (struct rx_superstate *super,
+		    struct rx_inx *answer, rx_Bitset trcset) 
+#else
+static void 
+install_transition (super, answer, trcset)
+     struct rx_superstate *super;
+     struct rx_inx *answer;
+     rx_Bitset trcset;
+#endif
+{
+  struct rx_inx * transitions = super->transitions;
+  int chr;
+  for (chr = 0; chr < 256; )
+    if (!*trcset)
+      {
+	++trcset;
+	chr += 32;
+      }
+    else
+      {
+	RX_subset sub = *trcset;
+	RX_subset mask = 1;
+	int bound = chr + 32;
+	while (chr < bound)
+	  {
+	    if (sub & mask)
+	      transitions [chr] = *answer;
+	    ++chr;
+	    mask <<= 1;
+	  }
+	++trcset;
+      }
+}
+
+
+#ifdef __STDC__
+static int
+qlen (struct rx_superstate * q)
+#else
+static int
+qlen (q)
+     struct rx_superstate * q;
+#endif
+{
+  int count = 1;
+  struct rx_superstate * it;
+  if (!q)
+    return 0;
+  for (it = q->next_recyclable; it != q; it = it->next_recyclable)
+    ++count;
+  return count;
+}
+
+#ifdef __STDC__
+static void
+check_cache (struct rx_cache * cache)
+#else
+static void
+check_cache (cache)
+     struct rx_cache * cache;
+#endif
+{
+  struct rx_cache * you_fucked_up = 0;
+  int total = cache->superstates;
+  int semi = cache->semifree_superstates;
+  if (semi != qlen (cache->semifree_superstate))
+    check_cache (you_fucked_up);
+  if ((total - semi) != qlen (cache->lru_superstate))
+    check_cache (you_fucked_up);
+}
+
+/* When a superstate is old and neglected, it can enter a 
+ * semi-free state.  A semi-free state is slated to die.
+ * Incoming transitions to a semi-free state are re-written
+ * to cause an (interpreted) fault when they are taken.
+ * The fault handler revives the semi-free state, patches
+ * incoming transitions back to normal, and continues.
+ *
+ * The idea is basicly to free in two stages, aborting 
+ * between the two if the state turns out to be useful again.
+ * When a free is aborted, the rescued superstate is placed
+ * in the most-favored slot to maximize the time until it
+ * is next semi-freed.
+ */
+
+#ifdef __STDC__
+static void
+semifree_superstate (struct rx_cache * cache)
+#else
+static void
+semifree_superstate (cache)
+     struct rx_cache * cache;
+#endif
+{
+  int disqualified = cache->semifree_superstates;
+  if (disqualified == cache->superstates)
+    return;
+  while (cache->lru_superstate->locks)
+    {
+      cache->lru_superstate = cache->lru_superstate->next_recyclable;
+      ++disqualified;
+      if (disqualified == cache->superstates)
+	return;
+    }
+  {
+    struct rx_superstate * it = cache->lru_superstate;
+    it->next_recyclable->prev_recyclable = it->prev_recyclable;
+    it->prev_recyclable->next_recyclable = it->next_recyclable;
+    cache->lru_superstate = (it == it->next_recyclable
+			     ? 0
+			     : it->next_recyclable);
+    if (!cache->semifree_superstate)
+      {
+	cache->semifree_superstate = it;
+	it->next_recyclable = it;
+	it->prev_recyclable = it;
+      }
+    else
+      {
+	it->prev_recyclable = cache->semifree_superstate->prev_recyclable;
+	it->next_recyclable = cache->semifree_superstate;
+	it->prev_recyclable->next_recyclable = it;
+	it->next_recyclable->prev_recyclable = it;
+      }
+    {
+      struct rx_distinct_future *df;
+      it->is_semifree = 1;
+      ++cache->semifree_superstates;
+      df = it->transition_refs;
+      if (df)
+	{
+	  df->prev_same_dest->next_same_dest = 0;
+	  for (df = it->transition_refs; df; df = df->next_same_dest)
+	    {
+	      df->future_frame.inx = cache->instruction_table[rx_cache_miss];
+	      df->future_frame.data = 0;
+	      df->future_frame.data_2 = (void *) df;
+	      /* If there are any NEXT-CHAR instruction frames that
+	       * refer to this state, we convert them to CACHE-MISS frames.
+	       */
+	      if (!df->effects
+		  && (df->edge->options->next_same_super_edge[0]
+		      == df->edge->options))
+		install_transition (df->present, &df->future_frame,
+				    df->edge->cset);
+	    }
+	  df = it->transition_refs;
+	  df->prev_same_dest->next_same_dest = df;
+	}
+    }
+  }
+}
+
+
+#ifdef __STDC__
+static void 
+refresh_semifree_superstate (struct rx_cache * cache,
+			     struct rx_superstate * super)
+#else
+static void 
+refresh_semifree_superstate (cache, super)
+     struct rx_cache * cache;
+     struct rx_superstate * super;
+#endif
+{
+  struct rx_distinct_future *df;
+
+  if (super->transition_refs)
+    {
+      super->transition_refs->prev_same_dest->next_same_dest = 0; 
+      for (df = super->transition_refs; df; df = df->next_same_dest)
+	{
+	  df->future_frame.inx = cache->instruction_table[rx_next_char];
+	  df->future_frame.data = (void *) super->transitions;
+	  /* CACHE-MISS instruction frames that refer to this state,
+	   * must be converted to NEXT-CHAR frames.
+	   */
+	  if (!df->effects
+	      && (df->edge->options->next_same_super_edge[0]
+		  == df->edge->options))
+	    install_transition (df->present, &df->future_frame,
+				df->edge->cset);
+	}
+      super->transition_refs->prev_same_dest->next_same_dest
+	= super->transition_refs;
+    }
+  if (cache->semifree_superstate == super)
+    cache->semifree_superstate = (super->prev_recyclable == super
+				  ? 0
+				  : super->prev_recyclable);
+  super->next_recyclable->prev_recyclable = super->prev_recyclable;
+  super->prev_recyclable->next_recyclable = super->next_recyclable;
+
+  if (!cache->lru_superstate)
+    (cache->lru_superstate
+     = super->next_recyclable
+     = super->prev_recyclable
+     = super);
+  else
+    {
+      super->next_recyclable = cache->lru_superstate;
+      super->prev_recyclable = cache->lru_superstate->prev_recyclable;
+      super->next_recyclable->prev_recyclable = super;
+      super->prev_recyclable->next_recyclable = super;
+    }
+  super->is_semifree = 0;
+  --cache->semifree_superstates;
+}
+
+#ifdef __STDC__
+static void
+rx_refresh_this_superstate (struct rx_cache * cache, struct rx_superstate * superstate)
+#else
+static void
+rx_refresh_this_superstate (cache, superstate)
+     struct rx_cache * cache;
+     struct rx_superstate * superstate;
+#endif
+{
+  if (superstate->is_semifree)
+    refresh_semifree_superstate (cache, superstate);
+  else if (cache->lru_superstate == superstate)
+    cache->lru_superstate = superstate->next_recyclable;
+  else if (superstate != cache->lru_superstate->prev_recyclable)
+    {
+      superstate->next_recyclable->prev_recyclable
+	= superstate->prev_recyclable;
+      superstate->prev_recyclable->next_recyclable
+	= superstate->next_recyclable;
+      superstate->next_recyclable = cache->lru_superstate;
+      superstate->prev_recyclable = cache->lru_superstate->prev_recyclable;
+      superstate->next_recyclable->prev_recyclable = superstate;
+      superstate->prev_recyclable->next_recyclable = superstate;
+    }
+}
+
+#ifdef __STDC__
+static void 
+release_superset_low (struct rx_cache * cache,
+		     struct rx_superset *set)
+#else
+static void 
+release_superset_low (cache, set)
+     struct rx_cache * cache;
+     struct rx_superset *set;
+#endif
+{
+  if (!--set->refs)
+    {
+      if (set->cdr)
+	release_superset_low (cache, set->cdr);
+
+      set->starts_for = 0;
+
+      rx_hash_free
+	(rx_hash_find
+	 (&cache->superset_table,
+	  (unsigned long)set->car ^ set->id ^ (unsigned long)set->cdr,
+	  (void *)set,
+	  &cache->superset_hash_rules),
+	 &cache->superset_hash_rules);
+      rx_cache_free (cache, &cache->free_supersets, (char *)set);
+    }
+}
+
+#ifdef __STDC__
+RX_DECL void 
+rx_release_superset (struct rx *rx,
+		     struct rx_superset *set)
+#else
+RX_DECL void 
+rx_release_superset (rx, set)
+     struct rx *rx;
+     struct rx_superset *set;
+#endif
+{
+  release_superset_low (rx->cache, set);
+}
+
+/* This tries to add a new superstate to the superstate freelist.
+ * It might, as a result, free some edge pieces or hash tables.
+ * If nothing can be freed because too many locks are being held, fail.
+ */
+
+#ifdef __STDC__
+static int
+rx_really_free_superstate (struct rx_cache * cache)
+#else
+static int
+rx_really_free_superstate (cache)
+     struct rx_cache * cache;
+#endif
+{
+  int locked_superstates = 0;
+  struct rx_superstate * it;
+
+  if (!cache->superstates)
+    return 0;
+
+  {
+    /* This is a total guess.  The idea is that we should expect as
+     * many misses as we've recently experienced.  I.e., cache->misses
+     * should be the same as cache->semifree_superstates.
+     */
+    while ((cache->hits + cache->misses) > cache->superstates_allowed)
+      {
+	cache->hits >>= 1;
+	cache->misses >>= 1;
+      }
+    if (  ((cache->hits + cache->misses) * cache->semifree_superstates)
+	< (cache->superstates		 * cache->misses))
+      {
+	semifree_superstate (cache);
+	semifree_superstate (cache);
+      }
+  }
+
+  while (cache->semifree_superstate && cache->semifree_superstate->locks)
+    {
+      refresh_semifree_superstate (cache, cache->semifree_superstate);
+      ++locked_superstates;
+      if (locked_superstates == cache->superstates)
+	return 0;
+    }
+
+  if (cache->semifree_superstate)
+    {
+      it = cache->semifree_superstate;
+      it->next_recyclable->prev_recyclable = it->prev_recyclable;
+      it->prev_recyclable->next_recyclable = it->next_recyclable;
+      cache->semifree_superstate = ((it == it->next_recyclable)
+				    ? 0
+				    : it->next_recyclable);
+      --cache->semifree_superstates;
+    }
+  else
+    {
+      while (cache->lru_superstate->locks)
+	{
+	  cache->lru_superstate = cache->lru_superstate->next_recyclable;
+	  ++locked_superstates;
+	  if (locked_superstates == cache->superstates)
+	    return 0;
+	}
+      it = cache->lru_superstate;
+      it->next_recyclable->prev_recyclable = it->prev_recyclable;
+      it->prev_recyclable->next_recyclable = it->next_recyclable;
+      cache->lru_superstate = ((it == it->next_recyclable)
+				    ? 0
+				    : it->next_recyclable);
+    }
+
+  if (it->transition_refs)
+    {
+      struct rx_distinct_future *df;
+      for (df = it->transition_refs,
+	   df->prev_same_dest->next_same_dest = 0;
+	   df;
+	   df = df->next_same_dest)
+	{
+	  df->future_frame.inx = cache->instruction_table[rx_cache_miss];
+	  df->future_frame.data = 0;
+	  df->future_frame.data_2 = (void *) df;
+	  df->future = 0;
+	}
+      it->transition_refs->prev_same_dest->next_same_dest =
+	it->transition_refs;
+    }
+  {
+    struct rx_super_edge *tc = it->edges;
+    while (tc)
+      {
+	struct rx_distinct_future * df;
+	struct rx_super_edge *tct = tc->next;
+	df = tc->options;
+	df->next_same_super_edge[1]->next_same_super_edge[0] = 0;
+	while (df)
+	  {
+	    struct rx_distinct_future *dft = df;
+	    df = df->next_same_super_edge[0];
+	    
+	    
+	    if (dft->future && dft->future->transition_refs == dft)
+	      {
+		dft->future->transition_refs = dft->next_same_dest;
+		if (dft->future->transition_refs == dft)
+		  dft->future->transition_refs = 0;
+	      }
+	    dft->next_same_dest->prev_same_dest = dft->prev_same_dest;
+	    dft->prev_same_dest->next_same_dest = dft->next_same_dest;
+	    rx_cache_free (cache, &cache->free_discernable_futures,
+			   (char *)dft);
+	  }
+	rx_cache_free (cache, &cache->free_transition_classes, (char *)tc);
+	tc = tct;
+      }
+  }
+  
+  if (it->contents->superstate == it)
+    it->contents->superstate = 0;
+  release_superset_low (cache, it->contents);
+  rx_cache_free (cache, &cache->free_superstates, (char *)it);
+  --cache->superstates;
+  return 1;
+}
+
+#ifdef __STDC__
+static char *
+rx_cache_get (struct rx_cache * cache,
+	      struct rx_freelist ** freelist)
+#else
+static char *
+rx_cache_get (cache, freelist)
+     struct rx_cache * cache;
+     struct rx_freelist ** freelist;
+#endif
+{
+  while (!*freelist && rx_really_free_superstate (cache))
+    ;
+  if (!*freelist)
+    return 0;
+  {
+    struct rx_freelist * it = *freelist;
+    *freelist = it->next;
+    return (char *)it;
+  }
+}
+
+#ifdef __STDC__
+static char *
+rx_cache_malloc_or_get (struct rx_cache * cache,
+			struct rx_freelist ** freelist, int bytes)
+#else
+static char *
+rx_cache_malloc_or_get (cache, freelist, bytes)
+     struct rx_cache * cache;
+     struct rx_freelist ** freelist;
+     int bytes;
+#endif
+{
+  if (!*freelist)
+    {
+      char * answer = rx_cache_malloc (cache, bytes);
+      if (answer)
+	return answer;
+    }
+
+  return rx_cache_get (cache, freelist);
+}
+
+#ifdef __STDC__
+static char *
+rx_cache_get_superstate (struct rx_cache * cache)
+#else
+static char *
+rx_cache_get_superstate (cache)
+	  struct rx_cache * cache;
+#endif
+{
+  char * answer;
+  int bytes = (   sizeof (struct rx_superstate)
+	       +  cache->local_cset_size * sizeof (struct rx_inx));
+  if (!cache->free_superstates
+      && (cache->superstates < cache->superstates_allowed))
+    {
+      answer = rx_cache_malloc (cache, bytes);
+      if (answer)
+	{
+	  ++cache->superstates;
+	  return answer;
+	}
+    }
+  answer = rx_cache_get (cache, &cache->free_superstates);
+  if (!answer)
+    {
+      answer = rx_cache_malloc (cache, bytes);
+      if (answer)
+	++cache->superstates_allowed;
+    }
+  ++cache->superstates;
+  return answer;
+}
+
+
+
+#ifdef __STDC__
+static int
+supersetcmp (void * va, void * vb)
+#else
+static int
+supersetcmp (va, vb)
+     void * va;
+     void * vb;
+#endif
+{
+  struct rx_superset * a = (struct rx_superset *)va;
+  struct rx_superset * b = (struct rx_superset *)vb;
+  return (   (a == b)
+	  || (a && b && (a->car == b->car) && (a->cdr == b->cdr)));
+}
+
+#ifdef __STDC__
+static struct rx_hash_item *
+superset_allocator (struct rx_hash_rules * rules, void * val)
+#else
+static struct rx_hash_item *
+superset_allocator (rules, val)
+     struct rx_hash_rules * rules;
+     void * val;
+#endif
+{
+  struct rx_cache * cache
+    = ((struct rx_cache *)
+       ((char *)rules
+	- (unsigned long)(&((struct rx_cache *)0)->superset_hash_rules)));
+  struct rx_superset * template = (struct rx_superset *)val;
+  struct rx_superset * newset
+    = ((struct rx_superset *)
+       rx_cache_malloc_or_get (cache,
+			       &cache->free_supersets,
+			       sizeof (*template)));
+  if (!newset)
+    return 0;
+  newset->refs = 0;
+  newset->car = template->car;
+  newset->id = template->car->id;
+  newset->cdr = template->cdr;
+  newset->superstate = 0;
+  rx_protect_superset (rx, template->cdr);
+  newset->hash_item.data = (void *)newset;
+  newset->hash_item.binding = 0;
+  return &newset->hash_item;
+}
+
+#ifdef __STDC__
+static struct rx_hash * 
+super_hash_allocator (struct rx_hash_rules * rules)
+#else
+static struct rx_hash * 
+super_hash_allocator (rules)
+     struct rx_hash_rules * rules;
+#endif
+{
+  struct rx_cache * cache
+    = ((struct rx_cache *)
+       ((char *)rules
+	- (unsigned long)(&((struct rx_cache *)0)->superset_hash_rules)));
+  return ((struct rx_hash *)
+	  rx_cache_malloc_or_get (cache,
+				  &cache->free_hash, sizeof (struct rx_hash)));
+}
+
+
+#ifdef __STDC__
+static void
+super_hash_liberator (struct rx_hash * hash, struct rx_hash_rules * rules)
+#else
+static void
+super_hash_liberator (hash, rules)
+     struct rx_hash * hash;
+     struct rx_hash_rules * rules;
+#endif
+{
+  struct rx_cache * cache
+    = ((struct rx_cache *)
+       (char *)rules - (long)(&((struct rx_cache *)0)->superset_hash_rules));
+  rx_cache_free (cache, &cache->free_hash, (char *)hash);
+}
+
+#ifdef __STDC__
+static void
+superset_hash_item_liberator (struct rx_hash_item * it,
+			      struct rx_hash_rules * rules)
+#else
+static void
+superset_hash_item_liberator (it, rules) /* Well, it does ya know. */
+     struct rx_hash_item * it;
+     struct rx_hash_rules * rules;
+#endif
+{
+}
+
+int rx_cache_bound = 128;
+static int rx_default_cache_got = 0;
+
+#ifdef __STDC__
+static int
+bytes_for_cache_size (int supers, int cset_size)
+#else
+static int
+bytes_for_cache_size (supers, cset_size)
+     int supers;
+     int cset_size;
+#endif
+{
+  /* What the hell is this? !!!*/
+  return (int)
+    ((float)supers *
+     (  (1.03 * (float) (  rx_sizeof_bitset (cset_size)
+			 + sizeof (struct rx_super_edge)))
+      + (1.80 * (float) sizeof (struct rx_possible_future))
+      + (float) (  sizeof (struct rx_superstate)
+		 + cset_size * sizeof (struct rx_inx))));
+}
+
+#ifdef __STDC__
+static void
+rx_morecore (struct rx_cache * cache)
+#else
+static void
+rx_morecore (cache)
+     struct rx_cache * cache;
+#endif
+{
+  if (rx_default_cache_got >= rx_cache_bound)
+    return;
+
+  rx_default_cache_got += 16;
+  cache->superstates_allowed = rx_cache_bound;
+  {
+    struct rx_blocklist ** pos = &cache->memory;
+    int size = bytes_for_cache_size (16, cache->local_cset_size);
+    while (*pos)
+      pos = &(*pos)->next;
+    *pos = ((struct rx_blocklist *)
+	    malloc (size + sizeof (struct rx_blocklist))); 
+    if (!*pos)
+      return;
+
+    (*pos)->next = 0;
+    (*pos)->bytes = size;
+    cache->memory_pos = *pos;
+    cache->memory_addr = (char *)*pos + sizeof (**pos);
+    cache->bytes_left = size;
+  }
+}
+
+static struct rx_cache default_cache = 
+{
+  {
+    supersetcmp,
+    super_hash_allocator,
+    super_hash_liberator,
+    superset_allocator,
+    superset_hash_item_liberator,
+  },
+  0,
+  0,
+  0,
+  0,
+  rx_morecore,
+
+  0,
+  0,
+  0,
+  0,
+  0,
+
+  0,
+  0,
+
+  0,
+
+  0,
+  0,
+  0,
+  0,
+  128,
+
+  256,
+  rx_id_instruction_table,
+
+  {
+    0,
+    0,
+    {0},
+    {0},
+    {0}
+  }
+};
+
+/* This adds an element to a superstate set.  These sets are lists, such
+ * that lists with == elements are ==.  The empty set is returned by
+ * superset_cons (rx, 0, 0) and is NOT equivelent to 
+ * (struct rx_superset)0.
+ */
+
+#ifdef __STDC__
+RX_DECL struct rx_superset *
+rx_superset_cons (struct rx * rx,
+		  struct rx_nfa_state *car, struct rx_superset *cdr)
+#else
+RX_DECL struct rx_superset *
+rx_superset_cons (rx, car, cdr)
+     struct rx * rx;
+     struct rx_nfa_state *car;
+     struct rx_superset *cdr;
+#endif
+{
+  struct rx_cache * cache = rx->cache;
+  if (!car && !cdr)
+    {
+      if (!cache->empty_superset)
+	{
+	  cache->empty_superset
+	    = ((struct rx_superset *)
+	       rx_cache_malloc_or_get (cache, &cache->free_supersets,
+				       sizeof (struct rx_superset)));
+	  if (!cache->empty_superset)
+	    return 0;
+	  bzero (cache->empty_superset, sizeof (struct rx_superset));
+	  cache->empty_superset->refs = 1000;
+	}
+      return cache->empty_superset;
+    }
+  {
+    struct rx_superset template;
+    struct rx_hash_item * hit;
+    template.car = car;
+    template.cdr = cdr;
+    template.id = car->id;
+    hit = rx_hash_store (&cache->superset_table,
+			 (unsigned long)car ^ car->id ^ (unsigned long)cdr,
+			 (void *)&template,
+			 &cache->superset_hash_rules);
+    return (hit
+	    ?  (struct rx_superset *)hit->data
+	    : 0);
+  }
+}
+
+/* This computes a union of two NFA state sets.  The sets do not have the
+ * same representation though.  One is a RX_SUPERSET structure (part
+ * of the superstate NFA) and the other is an NFA_STATE_SET (part of the NFA).
+ */
+
+#ifdef __STDC__
+RX_DECL struct rx_superset *
+rx_superstate_eclosure_union
+  (struct rx * rx, struct rx_superset *set, struct rx_nfa_state_set *ecl) 
+#else
+RX_DECL struct rx_superset *
+rx_superstate_eclosure_union (rx, set, ecl)
+     struct rx * rx;
+     struct rx_superset *set;
+     struct rx_nfa_state_set *ecl;
+#endif
+{
+  if (!ecl)
+    return set;
+
+  if (!set->car)
+    return rx_superset_cons (rx, ecl->car,
+			     rx_superstate_eclosure_union (rx, set, ecl->cdr));
+  if (set->car == ecl->car)
+    return rx_superstate_eclosure_union (rx, set, ecl->cdr);
+
+  {
+    struct rx_superset * tail;
+    struct rx_nfa_state * first;
+
+    if (set->car > ecl->car)
+      {
+	tail = rx_superstate_eclosure_union (rx, set->cdr, ecl);
+	first = set->car;
+      }
+    else
+      {
+	tail = rx_superstate_eclosure_union (rx, set, ecl->cdr);
+	first = ecl->car;
+      }
+    if (!tail)
+      return 0;
+    else
+      {
+	struct rx_superset * answer;
+	answer = rx_superset_cons (rx, first, tail);
+	if (!answer)
+	  {
+	    rx_protect_superset (rx, tail);
+	    rx_release_superset (rx, tail);
+	    return 0;
+	  }
+	else
+	  return answer;
+      }
+  }
+}
+
+
+
+
+/*
+ * This makes sure that a list of rx_distinct_futures contains
+ * a future for each possible set of side effects in the eclosure
+ * of a given state.  This is some of the work of filling in a
+ * superstate transition. 
+ */
+
+#ifdef __STDC__
+static struct rx_distinct_future *
+include_futures (struct rx *rx,
+		 struct rx_distinct_future *df, struct rx_nfa_state
+		 *state, struct rx_superstate *superstate) 
+#else
+static struct rx_distinct_future *
+include_futures (rx, df, state, superstate)
+     struct rx *rx;
+     struct rx_distinct_future *df;
+     struct rx_nfa_state *state;
+     struct rx_superstate *superstate;
+#endif
+{
+  struct rx_possible_future *future;
+  struct rx_cache * cache = rx->cache;
+  for (future = state->futures; future; future = future->next)
+    {
+      struct rx_distinct_future *dfp;
+      struct rx_distinct_future *insert_before = 0;
+      if (df)
+	df->next_same_super_edge[1]->next_same_super_edge[0] = 0;
+      for (dfp = df; dfp; dfp = dfp->next_same_super_edge[0])
+	if (dfp->effects == future->effects)
+	  break;
+	else
+	  {
+	    int order = rx->se_list_cmp (rx, dfp->effects, future->effects);
+	    if (order > 0)
+	      {
+		insert_before = dfp;
+		dfp = 0;
+		break;
+	      }
+	  }
+      if (df)
+	df->next_same_super_edge[1]->next_same_super_edge[0] = df;
+      if (!dfp)
+	{
+	  dfp
+	    = ((struct rx_distinct_future *)
+	       rx_cache_malloc_or_get (cache, &cache->free_discernable_futures,
+				       sizeof (struct rx_distinct_future)));
+	  if (!dfp)
+	    return 0;
+	  if (!df)
+	    {
+	      df = insert_before = dfp;
+	      df->next_same_super_edge[0] = df->next_same_super_edge[1] = df;
+	    }
+	  else if (!insert_before)
+	    insert_before = df;
+	  else if (insert_before == df)
+	    df = dfp;
+
+	  dfp->next_same_super_edge[0] = insert_before;
+	  dfp->next_same_super_edge[1]
+	    = insert_before->next_same_super_edge[1];
+	  dfp->next_same_super_edge[1]->next_same_super_edge[0] = dfp;
+	  dfp->next_same_super_edge[0]->next_same_super_edge[1] = dfp;
+	  dfp->next_same_dest = dfp->prev_same_dest = dfp;
+	  dfp->future = 0;
+	  dfp->present = superstate;
+	  dfp->future_frame.inx = rx->instruction_table[rx_cache_miss];
+	  dfp->future_frame.data = 0;
+	  dfp->future_frame.data_2 = (void *) dfp;
+	  dfp->side_effects_frame.inx
+	    = rx->instruction_table[rx_do_side_effects];
+	  dfp->side_effects_frame.data = 0;
+	  dfp->side_effects_frame.data_2 = (void *) dfp;
+	  dfp->effects = future->effects;
+	}
+    }
+  return df;
+}
+
+
+
+/* This constructs a new superstate from its state set.  The only 
+ * complexity here is memory management.
+ */
+#ifdef __STDC__
+RX_DECL struct rx_superstate *
+rx_superstate (struct rx *rx,
+	       struct rx_superset *set)
+#else
+RX_DECL struct rx_superstate *
+rx_superstate (rx, set)
+     struct rx *rx;
+     struct rx_superset *set;
+#endif
+{
+  struct rx_cache * cache = rx->cache;
+  struct rx_superstate * superstate = 0;
+
+  /* Does the superstate already exist in the cache? */
+  if (set->superstate)
+    {
+      if (set->superstate->rx_id != rx->rx_id)
+	{
+	  /* Aha.  It is in the cache, but belongs to a superstate
+	   * that refers to an NFA that no longer exists.
+	   * (We know it no longer exists because it was evidently
+	   *  stored in the same region of memory as the current nfa
+	   *  yet it has a different id.)
+	   */
+	  superstate = set->superstate;
+	  if (!superstate->is_semifree)
+	    {
+	      if (cache->lru_superstate == superstate)
+		{
+		  cache->lru_superstate = superstate->next_recyclable;
+		  if (cache->lru_superstate == superstate)
+		    cache->lru_superstate = 0;
+		}
+	      {
+		superstate->next_recyclable->prev_recyclable
+		  = superstate->prev_recyclable;
+		superstate->prev_recyclable->next_recyclable
+		  = superstate->next_recyclable;
+		if (!cache->semifree_superstate)
+		  {
+		    (cache->semifree_superstate
+		     = superstate->next_recyclable
+		     = superstate->prev_recyclable
+		     = superstate);
+		  }
+		else
+		  {
+		    superstate->next_recyclable = cache->semifree_superstate;
+		    superstate->prev_recyclable
+		      = cache->semifree_superstate->prev_recyclable;
+		    superstate->next_recyclable->prev_recyclable
+		      = superstate;
+		    superstate->prev_recyclable->next_recyclable
+		      = superstate;
+		    cache->semifree_superstate = superstate;
+		  }
+		++cache->semifree_superstates;
+	      }
+	    }
+	  set->superstate = 0;
+	  goto handle_cache_miss;
+	}
+      ++cache->hits;
+      superstate = set->superstate;
+
+      rx_refresh_this_superstate (cache, superstate);
+      return superstate;
+    }
+
+ handle_cache_miss:
+
+  /* This point reached only for cache misses. */
+  ++cache->misses;
+#if RX_DEBUG
+  if (rx_debug_trace > 1)
+    {
+      struct rx_superset * setp = set;
+      fprintf (stderr, "Building a superstet %d(%d): ", rx->rx_id, set);
+      while (setp)
+	{
+	  fprintf (stderr, "%d ", setp->id);
+	  setp = setp->cdr;
+	}
+      fprintf (stderr, "(%d)\n", set);
+    }
+#endif
+  superstate = (struct rx_superstate *)rx_cache_get_superstate (cache);
+  if (!superstate)
+    return 0;
+
+  if (!cache->lru_superstate)
+    (cache->lru_superstate
+     = superstate->next_recyclable
+     = superstate->prev_recyclable
+     = superstate);
+  else
+    {
+      superstate->next_recyclable = cache->lru_superstate;
+      superstate->prev_recyclable = cache->lru_superstate->prev_recyclable;
+      (  superstate->prev_recyclable->next_recyclable
+       = superstate->next_recyclable->prev_recyclable
+       = superstate);
+    }
+  superstate->rx_id = rx->rx_id;
+  superstate->transition_refs = 0;
+  superstate->locks = 0;
+  superstate->is_semifree = 0;
+  set->superstate = superstate;
+  superstate->contents = set;
+  rx_protect_superset (rx, set);
+  superstate->edges = 0;
+  {
+    int x;
+    /* None of the transitions from this superstate are known yet. */
+    for (x = 0; x < rx->local_cset_size; ++x) /* &&&&& 3.8 % */
+      {
+	struct rx_inx * ifr = &superstate->transitions[x];
+	ifr->inx = rx->instruction_table [rx_cache_miss];
+	ifr->data = ifr->data_2 = 0;
+      }
+  }
+  return superstate;
+}
+
+
+/* This computes the destination set of one edge of the superstate NFA.
+ * Note that a RX_DISTINCT_FUTURE is a superstate edge.
+ * Returns 0 on an allocation failure.
+ */
+
+#ifdef __STDC__
+static int 
+solve_destination (struct rx *rx, struct rx_distinct_future *df)
+#else
+static int 
+solve_destination (rx, df)
+     struct rx *rx;
+     struct rx_distinct_future *df;
+#endif
+{
+  struct rx_super_edge *tc = df->edge;
+  struct rx_superset *nfa_state;
+  struct rx_superset *nil_set = rx_superset_cons (rx, 0, 0);
+  struct rx_superset *solution = nil_set;
+  struct rx_superstate *dest;
+
+  rx_protect_superset (rx, solution);
+  /* Iterate over all NFA states in the state set of this superstate. */
+  for (nfa_state = df->present->contents;
+       nfa_state->car;
+       nfa_state = nfa_state->cdr)
+    {
+      struct rx_nfa_edge *e;
+      /* Iterate over all edges of each NFA state. */
+      for (e = nfa_state->car->edges; e; e = e->next)
+        /* If we find an edge that is labeled with 
+	 * the characters we are solving for.....
+	 */
+	if (rx_bitset_is_subset (rx->local_cset_size,
+				 tc->cset, e->params.cset))
+	  {
+	    struct rx_nfa_state *n = e->dest;
+	    struct rx_possible_future *pf;
+	    /* ....search the partial epsilon closures of the destination
+	     * of that edge for a path that involves the same set of
+	     * side effects we are solving for.
+	     * If we find such a RX_POSSIBLE_FUTURE, we add members to the
+	     * stateset we are computing.
+	     */
+	    for (pf = n->futures; pf; pf = pf->next)
+	      if (pf->effects == df->effects)
+		{
+		  struct rx_superset * old_sol;
+		  old_sol = solution;
+		  solution = rx_superstate_eclosure_union (rx, solution,
+							   pf->destset);
+		  if (!solution)
+		    return 0;
+		  rx_protect_superset (rx, solution);
+		  rx_release_superset (rx, old_sol);
+		}
+	  }
+    }
+  /* It is possible that the RX_DISTINCT_FUTURE we are working on has 
+   * the empty set of NFA states as its definition.  In that case, this
+   * is a failure point.
+   */
+  if (solution == nil_set)
+    {
+      df->future_frame.inx = (void *) rx_backtrack;
+      df->future_frame.data = 0;
+      df->future_frame.data_2 = 0;
+      return 1;
+    }
+  dest = rx_superstate (rx, solution);
+  rx_release_superset (rx, solution);
+  if (!dest)
+    return 0;
+
+  {
+    struct rx_distinct_future *dft;
+    dft = df;
+    df->prev_same_dest->next_same_dest = 0;
+    while (dft)
+      {
+	dft->future = dest;
+	dft->future_frame.inx = rx->instruction_table[rx_next_char];
+	dft->future_frame.data = (void *) dest->transitions;
+	dft = dft->next_same_dest;
+      }
+    df->prev_same_dest->next_same_dest = df;
+  }
+  if (!dest->transition_refs)
+    dest->transition_refs = df;
+  else
+    {
+      struct rx_distinct_future *dft = dest->transition_refs->next_same_dest;
+      dest->transition_refs->next_same_dest = df->next_same_dest;
+      df->next_same_dest->prev_same_dest = dest->transition_refs;
+      df->next_same_dest = dft;
+      dft->prev_same_dest = df;
+    }
+  return 1;
+}
+
+
+/* This takes a superstate and a character, and computes some edges
+ * from the superstate NFA.  In particular, this computes all edges
+ * that lead from SUPERSTATE given CHR.   This function also 
+ * computes the set of characters that share this edge set.
+ * This returns 0 on allocation error.
+ * The character set and list of edges are returned through 
+ * the paramters CSETOUT and DFOUT.
+} */
+
+#ifdef __STDC__
+static int 
+compute_super_edge (struct rx *rx, struct rx_distinct_future **dfout,
+			  rx_Bitset csetout, struct rx_superstate *superstate,
+			  unsigned char chr)  
+#else
+static int 
+compute_super_edge (rx, dfout, csetout, superstate, chr)
+     struct rx *rx;
+     struct rx_distinct_future **dfout;
+     rx_Bitset csetout;
+     struct rx_superstate *superstate;
+     unsigned char chr;
+#endif
+{
+  struct rx_superset *stateset = superstate->contents;
+
+  /* To compute the set of characters that share edges with CHR, 
+   * we start with the full character set, and subtract.
+   */
+  rx_bitset_universe (rx->local_cset_size, csetout);
+  *dfout = 0;
+
+  /* Iterate over the NFA states in the superstate state-set. */
+  while (stateset->car)
+    {
+      struct rx_nfa_edge *e;
+      for (e = stateset->car->edges; e; e = e->next)
+	if (RX_bitset_member (e->params.cset, chr))
+	  {
+	    /* If we find an NFA edge that applies, we make sure there
+	     * are corresponding edges in the superstate NFA.
+	     */
+	    {
+	      struct rx_distinct_future * saved;
+	      saved = *dfout;
+	      *dfout = include_futures (rx, *dfout, e->dest, superstate);
+	      if (!*dfout)
+		{
+		  struct rx_distinct_future * df;
+		  df = saved;
+		  df->next_same_super_edge[1]->next_same_super_edge[0] = 0;
+		  while (df)
+		    {
+		      struct rx_distinct_future *dft;
+		      dft = df;
+		      df = df->next_same_super_edge[0];
+
+		      if (dft->future && dft->future->transition_refs == dft)
+			{
+			  dft->future->transition_refs = dft->next_same_dest;
+			  if (dft->future->transition_refs == dft)
+			    dft->future->transition_refs = 0;
+			}
+		      dft->next_same_dest->prev_same_dest = dft->prev_same_dest;
+		      dft->prev_same_dest->next_same_dest = dft->next_same_dest;
+		      rx_cache_free (rx->cache,
+				     &rx->cache->free_discernable_futures,
+				     (char *)dft);
+		    }
+		  return 0;
+		}
+	    }
+	    /* We also trim the character set a bit. */
+	    rx_bitset_intersection (rx->local_cset_size,
+				    csetout, e->params.cset);
+	  }
+	else
+	  /* An edge that doesn't apply at least tells us some characters
+	   * that don't share the same edge set as CHR.
+	   */
+	  rx_bitset_difference (rx->local_cset_size, csetout, e->params.cset);
+      stateset = stateset->cdr;
+    }
+  return 1;
+}
+
+
+/* This is a constructor for RX_SUPER_EDGE structures.  These are
+ * wrappers for lists of superstate NFA edges that share character sets labels.
+ * If a transition class contains more than one rx_distinct_future (superstate
+ * edge), then it represents a non-determinism in the superstate NFA.
+ */
+
+#ifdef __STDC__
+static struct rx_super_edge *
+rx_super_edge (struct rx *rx,
+	       struct rx_superstate *super, rx_Bitset cset,
+	       struct rx_distinct_future *df) 
+#else
+static struct rx_super_edge *
+rx_super_edge (rx, super, cset, df)
+     struct rx *rx;
+     struct rx_superstate *super;
+     rx_Bitset cset;
+     struct rx_distinct_future *df;
+#endif
+{
+  struct rx_super_edge *tc =
+    (struct rx_super_edge *)rx_cache_malloc_or_get
+      (rx->cache, &rx->cache->free_transition_classes,
+       sizeof (struct rx_super_edge) + rx_sizeof_bitset (rx->local_cset_size));
+
+  if (!tc)
+    return 0;
+  tc->next = super->edges;
+  super->edges = tc;
+  tc->rx_backtrack_frame.inx = rx->instruction_table[rx_backtrack_point];
+  tc->rx_backtrack_frame.data = 0;
+  tc->rx_backtrack_frame.data_2 = (void *) tc;
+  tc->options = df;
+  tc->cset = (rx_Bitset) ((char *) tc + sizeof (*tc));
+  rx_bitset_assign (rx->local_cset_size, tc->cset, cset);
+  if (df)
+    {
+      struct rx_distinct_future * dfp = df;
+      df->next_same_super_edge[1]->next_same_super_edge[0] = 0;
+      while (dfp)
+	{
+	  dfp->edge = tc;
+	  dfp = dfp->next_same_super_edge[0];
+	}
+      df->next_same_super_edge[1]->next_same_super_edge[0] = df;
+    }
+  return tc;
+}
+
+
+/* There are three kinds of cache miss.  The first occurs when a
+ * transition is taken that has never been computed during the
+ * lifetime of the source superstate.  That cache miss is handled by
+ * calling COMPUTE_SUPER_EDGE.  The second kind of cache miss
+ * occurs when the destination superstate of a transition doesn't
+ * exist.  SOLVE_DESTINATION is used to construct the destination superstate.
+ * Finally, the third kind of cache miss occurs when the destination
+ * superstate of a transition is in a `semi-free state'.  That case is
+ * handled by UNFREE_SUPERSTATE.
+ *
+ * The function of HANDLE_CACHE_MISS is to figure out which of these
+ * cases applies.
+ */
+
+#ifdef __STDC__
+static void
+install_partial_transition  (struct rx_superstate *super,
+			     struct rx_inx *answer,
+			     RX_subset set, int offset)
+#else
+static void
+install_partial_transition  (super, answer, set, offset)
+     struct rx_superstate *super;
+     struct rx_inx *answer;
+     RX_subset set;
+     int offset;
+#endif
+{
+  int start = offset;
+  int end = start + 32;
+  RX_subset pos = 1;
+  struct rx_inx * transitions = super->transitions;
+  
+  while (start < end)
+    {
+      if (set & pos)
+	transitions[start] = *answer;
+      pos <<= 1;
+      ++start;
+    }
+}
+
+
+#ifdef __STDC__
+RX_DECL struct rx_inx *
+rx_handle_cache_miss
+  (struct rx *rx, struct rx_superstate *super, unsigned char chr, void *data) 
+#else
+RX_DECL struct rx_inx *
+rx_handle_cache_miss (rx, super, chr, data)
+     struct rx *rx;
+     struct rx_superstate *super;
+     unsigned char chr;
+     void *data;
+#endif
+{
+  int offset = chr / RX_subset_bits;
+  struct rx_distinct_future *df = data;
+
+  if (!df)			/* must be the shared_cache_miss_frame */
+    {
+      /* Perhaps this is just a transition waiting to be filled. */
+      struct rx_super_edge *tc;
+      RX_subset mask = rx_subset_singletons [chr % RX_subset_bits];
+
+      for (tc = super->edges; tc; tc = tc->next)
+	if (tc->cset[offset] & mask)
+	  {
+	    struct rx_inx * answer;
+	    df = tc->options;
+	    answer = ((tc->options->next_same_super_edge[0] != tc->options)
+		      ? &tc->rx_backtrack_frame
+		      : (df->effects
+			 ? &df->side_effects_frame
+			 : &df->future_frame));
+	    install_partial_transition (super, answer,
+					tc->cset [offset], offset * 32);
+	    return answer;
+	  }
+      /* Otherwise, it's a flushed or  newly encountered edge. */
+      {
+	char cset_space[1024];	/* this limit is far from unreasonable */
+	rx_Bitset trcset;
+	struct rx_inx *answer;
+
+	if (rx_sizeof_bitset (rx->local_cset_size) > sizeof (cset_space))
+	  return 0;		/* If the arbitrary limit is hit, always fail */
+				/* cleanly. */
+	trcset = (rx_Bitset)cset_space;
+	rx_lock_superstate (rx, super);
+	if (!compute_super_edge (rx, &df, trcset, super, chr))
+	  {
+	    rx_unlock_superstate (rx, super);
+	    return 0;
+	  }
+	if (!df)		/* We just computed the fail transition. */
+	  {
+	    static struct rx_inx
+	      shared_fail_frame = { 0, 0, (void *)rx_backtrack, 0 };
+	    answer = &shared_fail_frame;
+	  }
+	else
+	  {
+	    tc = rx_super_edge (rx, super, trcset, df);
+	    if (!tc)
+	      {
+		rx_unlock_superstate (rx, super);
+		return 0;
+	      }
+	    answer = ((tc->options->next_same_super_edge[0] != tc->options)
+		      ? &tc->rx_backtrack_frame
+		      : (df->effects
+			 ? &df->side_effects_frame
+			 : &df->future_frame));
+	  }
+	install_partial_transition (super, answer,
+				    trcset[offset], offset * 32);
+	rx_unlock_superstate (rx, super);
+	return answer;
+      }
+    }
+  else if (df->future) /* A cache miss on an edge with a future? Must be
+			* a semi-free destination. */
+    {				
+      if (df->future->is_semifree)
+	refresh_semifree_superstate (rx->cache, df->future);
+      return &df->future_frame;
+    }
+  else
+    /* no future superstate on an existing edge */
+    {
+      rx_lock_superstate (rx, super);
+      if (!solve_destination (rx, df))
+	{
+	  rx_unlock_superstate (rx, super);
+	  return 0;
+	}
+      if (!df->effects
+	  && (df->edge->options->next_same_super_edge[0] == df->edge->options))
+	install_partial_transition (super, &df->future_frame,
+				    df->edge->cset[offset], offset * 32);
+      rx_unlock_superstate (rx, super);
+      return &df->future_frame;
+    }
+}
+
+
+
+
+/* The rest of the code provides a regex.c compatable interface. */
+
+
+__const__ char *re_error_msg[] =
+{
+  0,						/* REG_NOUT */
+  "No match",					/* REG_NOMATCH */
+  "Invalid regular expression",			/* REG_BADPAT */
+  "Invalid collation character",		/* REG_ECOLLATE */
+  "Invalid character class name",		/* REG_ECTYPE */
+  "Trailing backslash",				/* REG_EESCAPE */
+  "Invalid back reference",			/* REG_ESUBREG */
+  "Unmatched [ or [^",				/* REG_EBRACK */
+  "Unmatched ( or \\(",				/* REG_EPAREN */
+  "Unmatched \\{",				/* REG_EBRACE */
+  "Invalid content of \\{\\}",			/* REG_BADBR */
+  "Invalid range end",				/* REG_ERANGE */
+  "Memory exhausted",				/* REG_ESPACE */
+  "Invalid preceding regular expression",	/* REG_BADRPT */
+  "Premature end of regular expression",	/* REG_EEND */
+  "Regular expression too big",			/* REG_ESIZE */
+  "Unmatched ) or \\)",				/* REG_ERPAREN */
+};
+
+
+
+/* 
+ * Macros used while compiling patterns.
+ *
+ * By convention, PEND points just past the end of the uncompiled pattern,
+ * P points to the read position in the pattern.  `translate' is the name
+ * of the translation table (`TRANSLATE' is the name of a macro that looks
+ * things up in `translate').
+ */
+
+
+/*
+ * Fetch the next character in the uncompiled pattern---translating it 
+ * if necessary. *Also cast from a signed character in the constant
+ * string passed to us by the user to an unsigned char that we can use
+ * as an array index (in, e.g., `translate').
+ */
+#define PATFETCH(c)							\
+ do {if (p == pend) return REG_EEND;					\
+    c = (unsigned char) *p++;						\
+    c = translate[c];		 					\
+ } while (0)
+
+/* 
+ * Fetch the next character in the uncompiled pattern, with no
+ * translation.
+ */
+#define PATFETCH_RAW(c)							\
+  do {if (p == pend) return REG_EEND;					\
+    c = (unsigned char) *p++; 						\
+  } while (0)
+
+/* Go backwards one character in the pattern.  */
+#define PATUNFETCH p--
+
+
+#define TRANSLATE(d) translate[(unsigned char) (d)]
+
+typedef unsigned regnum_t;
+
+/* Since offsets can go either forwards or backwards, this type needs to
+ * be able to hold values from -(MAX_BUF_SIZE - 1) to MAX_BUF_SIZE - 1.
+ */
+typedef int pattern_offset_t;
+
+typedef struct
+{
+  struct rexp_node ** top_expression; /* was begalt */
+  struct rexp_node ** last_expression; /* was laststart */
+  pattern_offset_t inner_group_offset;
+  regnum_t regnum;
+} compile_stack_elt_t;
+
+typedef struct
+{
+  compile_stack_elt_t *stack;
+  unsigned size;
+  unsigned avail;			/* Offset of next open position.  */
+} compile_stack_type;
+
+
+#define INIT_COMPILE_STACK_SIZE 32
+
+#define COMPILE_STACK_EMPTY  (compile_stack.avail == 0)
+#define COMPILE_STACK_FULL  (compile_stack.avail == compile_stack.size)
+
+/* The next available element.  */
+#define COMPILE_STACK_TOP (compile_stack.stack[compile_stack.avail])
+
+
+/* Set the bit for character C in a list.  */
+#define SET_LIST_BIT(c)                               \
+  (b[((unsigned char) (c)) / CHARBITS]               \
+   |= 1 << (((unsigned char) c) % CHARBITS))
+
+/* Get the next unsigned number in the uncompiled pattern.  */
+#define GET_UNSIGNED_NUMBER(num) 					\
+  { if (p != pend)							\
+     {									\
+       PATFETCH (c); 							\
+       while (isdigit (c)) 						\
+         { 								\
+           if (num < 0)							\
+              num = 0;							\
+           num = num * 10 + c - '0'; 					\
+           if (p == pend) 						\
+              break; 							\
+           PATFETCH (c);						\
+         } 								\
+       } 								\
+    }		
+
+#define CHAR_CLASS_MAX_LENGTH  6 /* Namely, `xdigit'.  */
+
+#define IS_CHAR_CLASS(string)						\
+   (!strcmp (string, "alpha") || !strcmp (string, "upper")		\
+    || !strcmp (string, "lower") || !strcmp (string, "digit")		\
+    || !strcmp (string, "alnum") || !strcmp (string, "xdigit")		\
+    || !strcmp (string, "space") || !strcmp (string, "print")		\
+    || !strcmp (string, "punct") || !strcmp (string, "graph")		\
+    || !strcmp (string, "cntrl") || !strcmp (string, "blank"))
+
+
+/* These predicates are used in regex_compile. */
+
+/* P points to just after a ^ in PATTERN.  Return true if that ^ comes
+ * after an alternative or a begin-subexpression.  We assume there is at
+ * least one character before the ^.  
+ */
+
+#ifdef __STDC__
+static boolean
+at_begline_loc_p (__const__ char *pattern, __const__ char * p, reg_syntax_t syntax)
+#else
+static boolean
+at_begline_loc_p (pattern, p, syntax)
+     __const__ char *pattern;
+     __const__ char * p;
+     reg_syntax_t syntax;
+#endif
+{
+  __const__ char *prev = p - 2;
+  boolean prev_prev_backslash = ((prev > pattern) && (prev[-1] == '\\'));
+  
+    return
+      
+      (/* After a subexpression?  */
+       ((*prev == '(') && ((syntax & RE_NO_BK_PARENS) || prev_prev_backslash))
+       ||
+       /* After an alternative?  */
+       ((*prev == '|') && ((syntax & RE_NO_BK_VBAR) || prev_prev_backslash))
+       );
+}
+
+/* The dual of at_begline_loc_p.  This one is for $.  We assume there is
+ * at least one character after the $, i.e., `P < PEND'.
+ */
+
+#ifdef __STDC__
+static boolean
+at_endline_loc_p (__const__ char *p, __const__ char *pend, int syntax)
+#else
+static boolean
+at_endline_loc_p (p, pend, syntax)
+     __const__ char *p;
+     __const__ char *pend;
+     int syntax;
+#endif
+{
+  __const__ char *next = p;
+  boolean next_backslash = (*next == '\\');
+  __const__ char *next_next = (p + 1 < pend) ? (p + 1) : 0;
+  
+  return
+    (
+     /* Before a subexpression?  */
+     ((syntax & RE_NO_BK_PARENS)
+      ? (*next == ')')
+      : (next_backslash && next_next && (*next_next == ')')))
+    ||
+     /* Before an alternative?  */
+     ((syntax & RE_NO_BK_VBAR)
+      ? (*next == '|')
+      : (next_backslash && next_next && (*next_next == '|')))
+     );
+}
+
+
+unsigned char rx_id_translation[256] =
+{
+  0,  1,  2,  3,  4,  5,  6,  7,  8,  9,
+ 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
+ 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
+ 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
+ 40, 41, 42, 43, 44, 45, 46, 47, 48, 49,
+ 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,
+ 60, 61, 62, 63, 64, 65, 66, 67, 68, 69,
+ 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,
+ 80, 81, 82, 83, 84, 85, 86, 87, 88, 89,
+ 90, 91, 92, 93, 94, 95, 96, 97, 98, 99,
+
+ 100, 101, 102, 103, 104, 105, 106, 107, 108, 109,
+ 110, 111, 112, 113, 114, 115, 116, 117, 118, 119,
+ 120, 121, 122, 123, 124, 125, 126, 127, 128, 129,
+ 130, 131, 132, 133, 134, 135, 136, 137, 138, 139,
+ 140, 141, 142, 143, 144, 145, 146, 147, 148, 149,
+ 150, 151, 152, 153, 154, 155, 156, 157, 158, 159,
+ 160, 161, 162, 163, 164, 165, 166, 167, 168, 169,
+ 170, 171, 172, 173, 174, 175, 176, 177, 178, 179,
+ 180, 181, 182, 183, 184, 185, 186, 187, 188, 189,
+ 190, 191, 192, 193, 194, 195, 196, 197, 198, 199,
+
+ 200, 201, 202, 203, 204, 205, 206, 207, 208, 209,
+ 210, 211, 212, 213, 214, 215, 216, 217, 218, 219,
+ 220, 221, 222, 223, 224, 225, 226, 227, 228, 229,
+ 230, 231, 232, 233, 234, 235, 236, 237, 238, 239,
+ 240, 241, 242, 243, 244, 245, 246, 247, 248, 249,
+ 250, 251, 252, 253, 254, 255
+};
+
+/* The compiler keeps an inverted translation table.
+ * This looks up/inititalize elements.
+ * VALID is an array of booleans that validate CACHE.
+ */
+
+#ifdef __STDC__
+static rx_Bitset
+inverse_translation (struct re_pattern_buffer * rxb,
+		     char * valid, rx_Bitset cache,
+		     unsigned char * translate, int c)
+#else
+static rx_Bitset
+inverse_translation (rxb, valid, cache, translate, c)
+     struct re_pattern_buffer * rxb;
+     char * valid;
+     rx_Bitset cache;
+     unsigned char * translate;
+     int c;
+#endif
+{
+  rx_Bitset cs
+    = cache + c * rx_bitset_numb_subsets (rxb->rx.local_cset_size); 
+
+  if (!valid[c])
+    {
+      int x;
+      int c_tr = TRANSLATE(c);
+      rx_bitset_null (rxb->rx.local_cset_size, cs);
+      for (x = 0; x < 256; ++x)	/* &&&& 13.37 */
+	if (TRANSLATE(x) == c_tr)
+	  RX_bitset_enjoin (cs, x);
+      valid[c] = 1;
+    }
+  return cs;
+}
+
+
+
+
+/* More subroutine declarations and macros for regex_compile.  */
+
+/* Returns true if REGNUM is in one of COMPILE_STACK's elements and 
+   false if it's not.  */
+
+#ifdef __STDC__
+static boolean
+group_in_compile_stack (compile_stack_type compile_stack, regnum_t regnum)
+#else
+static boolean
+group_in_compile_stack (compile_stack, regnum)
+    compile_stack_type compile_stack;
+    regnum_t regnum;
+#endif
+{
+  int this_element;
+
+  for (this_element = compile_stack.avail - 1;  
+       this_element >= 0; 
+       this_element--)
+    if (compile_stack.stack[this_element].regnum == regnum)
+      return true;
+
+  return false;
+}
+
+
+/*
+ * Read the ending character of a range (in a bracket expression) from the
+ * uncompiled pattern *P_PTR (which ends at PEND).  We assume the
+ * starting character is in `P[-2]'.  (`P[-1]' is the character `-'.)
+ * Then we set the translation of all bits between the starting and
+ * ending characters (inclusive) in the compiled pattern B.
+ * 
+ * Return an error code.
+ * 
+ * We use these short variable names so we can use the same macros as
+ * `regex_compile' itself.  
+ */
+
+#ifdef __STDC__
+static reg_errcode_t
+compile_range (struct re_pattern_buffer * rxb, rx_Bitset cs,
+	       __const__ char ** p_ptr, __const__ char * pend,
+	       unsigned char * translate, reg_syntax_t syntax,
+	       rx_Bitset inv_tr,  char * valid_inv_tr)
+#else
+static reg_errcode_t
+compile_range (rxb, cs, p_ptr, pend, translate, syntax, inv_tr, valid_inv_tr)
+     struct re_pattern_buffer * rxb;
+     rx_Bitset cs;
+     __const__ char ** p_ptr;
+     __const__ char * pend;
+     unsigned char * translate;
+     reg_syntax_t syntax;
+     rx_Bitset inv_tr;
+     char * valid_inv_tr;
+#endif
+{
+  unsigned this_char;
+
+  __const__ char *p = *p_ptr;
+
+  unsigned char range_end;
+  unsigned char range_start = TRANSLATE(p[-2]);
+
+  if (p == pend)
+    return REG_ERANGE;
+
+  PATFETCH (range_end);
+
+  (*p_ptr)++;
+
+  if (range_start > range_end)
+    return syntax & RE_NO_EMPTY_RANGES ? REG_ERANGE : REG_NOERROR;
+
+  for (this_char = range_start; this_char <= range_end; this_char++)
+    {
+      rx_Bitset it =
+	inverse_translation (rxb, valid_inv_tr, inv_tr, translate, this_char);
+      rx_bitset_union (rxb->rx.local_cset_size, cs, it);
+    }
+  
+  return REG_NOERROR;
+}
+
+
+/* This searches a regexp for backreference side effects.
+ * It fills in the array OUT with 1 at the index of every register pair
+ * referenced by a backreference.
+ *
+ * This is used to help optimize patterns for searching.  The information is
+ * useful because, if the caller doesn't want register values, backreferenced
+ * registers are the only registers for which we need rx_backtrack.
+ */
+
+#ifdef __STDC__
+static void
+find_backrefs (char * out, struct rexp_node * rexp,
+	       struct re_se_params * params)
+#else
+static void
+find_backrefs (out, rexp, params)
+     char * out;
+     struct rexp_node * rexp;
+     struct re_se_params * params;
+#endif
+{
+  if (rexp)
+    switch (rexp->type)
+      {
+      case r_cset:
+      case r_data:
+	return;
+      case r_alternate:
+      case r_concat:
+      case r_opt:
+      case r_star:
+      case r_2phase_star:
+	find_backrefs (out, rexp->params.pair.left, params);
+	find_backrefs (out, rexp->params.pair.right, params);
+	return;
+      case r_side_effect:
+	if (   ((long)rexp->params.side_effect >= 0)
+	    && (params [(long)rexp->params.side_effect].se == re_se_backref))
+	  out[ params [(long)rexp->params.side_effect].op1] = 1;
+	return;
+      }
+}
+
+
+
+/* Returns 0 unless the pattern can match the empty string. */
+
+#ifdef __STDC__
+static int
+compute_fastset (struct re_pattern_buffer * rxb, struct rexp_node * rexp)
+#else
+static int
+compute_fastset (rxb, rexp)
+     struct re_pattern_buffer * rxb;
+     struct rexp_node * rexp;
+#endif
+{
+  if (!rexp)
+    return 1;
+  switch (rexp->type)
+    {
+    case r_data:
+      return 1;
+    case r_cset:
+      {
+	rx_bitset_union (rxb->rx.local_cset_size,
+			 rxb->fastset, rexp->params.cset);
+      }
+      return 0;
+    case r_concat:
+      return (compute_fastset (rxb, rexp->params.pair.left)
+	      && compute_fastset (rxb, rexp->params.pair.right));
+    case r_2phase_star:
+      compute_fastset (rxb, rexp->params.pair.left);
+      /* compute_fastset (rxb, rexp->params.pair.right);  nope... */
+      return 1;
+    case r_alternate:
+      return !!(compute_fastset (rxb, rexp->params.pair.left)
+		+ compute_fastset (rxb, rexp->params.pair.right));
+    case r_opt:
+    case r_star:
+      compute_fastset (rxb, rexp->params.pair.left);
+      return 1;
+    case r_side_effect:
+      return 1;
+    }
+
+  /* this should never happen */
+  return 0;
+}
+
+
+/* returns
+ *  1 -- yes, definately anchored by the given side effect.
+ *  2 -- maybe anchored, maybe the empty string.
+ *  0 -- definately not anchored
+ *  There is simply no other possibility.
+ */
+
+#ifdef __STDC__
+static int
+is_anchored (struct rexp_node * rexp, rx_side_effect se)
+#else
+static int
+is_anchored (rexp, se)
+     struct rexp_node * rexp;
+     rx_side_effect se;
+#endif
+{
+  if (!rexp)
+    return 2;
+  switch (rexp->type)
+    {
+    case r_cset:
+    case r_data:
+      return 0;
+    case r_concat:
+    case r_2phase_star:
+      {
+	int l = is_anchored (rexp->params.pair.left, se);
+	return (l == 2 ? is_anchored (rexp->params.pair.right, se) : l);
+      }
+    case r_alternate:
+      {
+	int l = is_anchored (rexp->params.pair.left, se);
+	int r = l ? is_anchored (rexp->params.pair.right, se) : 0;
+
+	if (l == r)
+	  return l;
+	else if ((l == 0) || (r == 0))
+	  return 0;
+	else
+	  return 2;
+      }
+    case r_opt:
+    case r_star:
+      return is_anchored (rexp->params.pair.left, se) ? 2 : 0;
+      
+    case r_side_effect:
+      return ((rexp->params.side_effect == se)
+	      ? 1 : 2);
+    }
+
+  /* this should never happen */
+  return 0;
+}
+
+
+/* This removes register assignments that aren't required by backreferencing.
+ * This can speed up explore_future, especially if it eliminates
+ * non-determinism in the superstate NFA.
+ * 
+ * NEEDED is an array of characters, presumably filled in by FIND_BACKREFS.
+ * The non-zero elements of the array indicate which register assignments
+ * can NOT be removed from the expression.
+ */
+
+#ifdef __STDC__
+static struct rexp_node *
+remove_unecessary_side_effects (struct rx * rx, char * needed,
+				struct rexp_node * rexp,
+				struct re_se_params * params)
+#else
+static struct rexp_node *
+remove_unecessary_side_effects (rx, needed, rexp, params)
+     struct rx * rx;
+     char * needed;
+     struct rexp_node * rexp;
+     struct re_se_params * params;
+#endif
+{
+  struct rexp_node * l;
+  struct rexp_node * r;
+  if (!rexp)
+    return 0;
+  else
+    switch (rexp->type)
+      {
+      case r_cset:
+      case r_data:
+	return rexp;
+      case r_alternate:
+      case r_concat:
+      case r_2phase_star:
+	l = remove_unecessary_side_effects (rx, needed,
+					    rexp->params.pair.left, params);
+	r = remove_unecessary_side_effects (rx, needed,
+					    rexp->params.pair.right, params);
+	if ((l && r) || (rexp->type != r_concat))
+	  {
+	    rexp->params.pair.left = l;
+	    rexp->params.pair.right = r;
+	    return rexp;
+	  }
+	else
+	  {
+	    rexp->params.pair.left = rexp->params.pair.right = 0;
+	    rx_free_rexp (rx, rexp);
+	    return l ? l : r;
+	  }
+      case r_opt:
+      case r_star:
+	l = remove_unecessary_side_effects (rx, needed,
+					    rexp->params.pair.left, params);
+	if (l)
+	  {
+	    rexp->params.pair.left = l;
+	    return rexp;
+	  }
+	else
+	  {
+	    rexp->params.pair.left = 0;
+	    rx_free_rexp (rx, rexp);
+	    return 0;
+	  }
+      case r_side_effect:
+	{
+	  int se = (long)rexp->params.side_effect;
+	  if (   (se >= 0)
+	      && (   ((enum re_side_effects)params[se].se == re_se_lparen)
+		  || ((enum re_side_effects)params[se].se == re_se_rparen))
+	      && (params [se].op1 > 0)
+	      && (!needed [params [se].op1]))
+	    {
+	      rx_free_rexp (rx, rexp);
+	      return 0;
+	    }
+	  else
+	    return rexp;
+	}
+      }
+
+  /* this should never happen */
+  return 0;
+}
+
+
+
+#ifdef __STDC__
+static int
+pointless_if_repeated (struct rexp_node * node, struct re_se_params * params)
+#else
+static int
+pointless_if_repeated (node, params)
+     struct rexp_node * node;
+     struct re_se_params * params;
+#endif
+{
+  if (!node)
+    return 1;
+  switch (node->type)
+    {
+    case r_cset:
+      return 0;
+    case r_alternate:
+    case r_concat:
+    case r_2phase_star:
+      return (pointless_if_repeated (node->params.pair.left, params)
+	      && pointless_if_repeated (node->params.pair.right, params));
+    case r_opt:
+    case r_star:
+      return pointless_if_repeated (node->params.pair.left, params);
+    case r_side_effect:
+      switch (((long)node->params.side_effect < 0)
+	      ? (enum re_side_effects)node->params.side_effect
+	      : (enum re_side_effects)params[(long)node->params.side_effect].se)
+	{
+	case re_se_try:
+	case re_se_at_dot:
+	case re_se_begbuf:
+	case re_se_hat:
+	case re_se_wordbeg:
+	case re_se_wordbound:
+	case re_se_notwordbound:
+	case re_se_wordend:
+	case re_se_endbuf:
+	case re_se_dollar:
+	case re_se_fail:
+	case re_se_win:
+	  return 1;
+	case re_se_lparen:
+	case re_se_rparen:
+	case re_se_iter:
+	case re_se_end_iter:
+	case re_se_syntax:
+	case re_se_not_syntax:
+	case re_se_backref:
+	  return 0;
+	}
+    case r_data:
+    default:
+      return 0;
+    }
+}
+
+
+
+#ifdef __STDC__
+static int
+registers_on_stack (struct re_pattern_buffer * rxb,
+		    struct rexp_node * rexp, int in_danger,
+		    struct re_se_params * params)
+#else
+static int
+registers_on_stack (rxb, rexp, in_danger, params)
+     struct re_pattern_buffer * rxb;
+     struct rexp_node * rexp;
+     int in_danger;
+     struct re_se_params * params;
+#endif
+{
+  if (!rexp)
+    return 0;
+  else
+    switch (rexp->type)
+      {
+      case r_cset:
+      case r_data:
+	return 0;
+      case r_alternate:
+      case r_concat:
+	return (   registers_on_stack (rxb, rexp->params.pair.left,
+				       in_danger, params)
+		|| (registers_on_stack
+		    (rxb, rexp->params.pair.right,
+		     in_danger, params)));
+      case r_opt:
+	return registers_on_stack (rxb, rexp->params.pair.left, 0, params);
+      case r_star:
+	return registers_on_stack (rxb, rexp->params.pair.left, 1, params);
+      case r_2phase_star:
+	return
+	  (   registers_on_stack (rxb, rexp->params.pair.left, 1, params)
+	   || registers_on_stack (rxb, rexp->params.pair.right, 1, params));
+      case r_side_effect:
+	{
+	  int se = (long)rexp->params.side_effect;
+	  if (   in_danger
+	      && (se >= 0)
+	      && (params [se].op1 > 0)
+	      && (   ((enum re_side_effects)params[se].se == re_se_lparen)
+		  || ((enum re_side_effects)params[se].se == re_se_rparen)))
+	    return 1;
+	  else
+	    return 0;
+	}
+      }
+
+  /* this should never happen */
+  return 0;
+}
+
+
+
+static char idempotent_complex_se[] =
+{
+#define RX_WANT_SE_DEFS 1
+#undef RX_DEF_SE
+#undef RX_DEF_CPLX_SE
+#define RX_DEF_SE(IDEM, NAME, VALUE)	      
+#define RX_DEF_CPLX_SE(IDEM, NAME, VALUE)     IDEM,
+#include "rx.h"
+#undef RX_DEF_SE
+#undef RX_DEF_CPLX_SE
+#undef RX_WANT_SE_DEFS
+  23
+};
+
+static char idempotent_se[] =
+{
+  13,
+#define RX_WANT_SE_DEFS 1
+#undef RX_DEF_SE
+#undef RX_DEF_CPLX_SE
+#define RX_DEF_SE(IDEM, NAME, VALUE)	      IDEM,
+#define RX_DEF_CPLX_SE(IDEM, NAME, VALUE)     
+#include "rx.h"
+#undef RX_DEF_SE
+#undef RX_DEF_CPLX_SE
+#undef RX_WANT_SE_DEFS
+  42
+};
+
+
+
+
+#ifdef __STDC__
+static int
+has_any_se (struct rx * rx,
+	    struct rexp_node * rexp)
+#else
+static int
+has_any_se (rx, rexp)
+     struct rx * rx;
+     struct rexp_node * rexp;
+#endif
+{
+  if (!rexp)
+    return 0;
+
+  switch (rexp->type)
+    {
+    case r_cset:
+    case r_data:
+      return 0;
+
+    case r_side_effect:
+      return 1;
+      
+    case r_2phase_star:
+    case r_concat:
+    case r_alternate:
+      return
+	(   has_any_se (rx, rexp->params.pair.left)
+	 || has_any_se (rx, rexp->params.pair.right));
+
+    case r_opt:
+    case r_star:
+      return has_any_se (rx, rexp->params.pair.left);
+    }
+
+  /* this should never happen */
+  return 0;
+}
+
+
+
+/* This must be called AFTER `convert_hard_loops' for a given REXP. */
+#ifdef __STDC__
+static int
+has_non_idempotent_epsilon_path (struct rx * rx,
+				 struct rexp_node * rexp,
+				 struct re_se_params * params)
+#else
+static int
+has_non_idempotent_epsilon_path (rx, rexp, params)
+     struct rx * rx;
+     struct rexp_node * rexp;
+     struct re_se_params * params;
+#endif
+{
+  if (!rexp)
+    return 0;
+
+  switch (rexp->type)
+    {
+    case r_cset:
+    case r_data:
+    case r_star:
+      return 0;
+
+    case r_side_effect:
+      return
+	!((long)rexp->params.side_effect > 0
+	  ? idempotent_complex_se [ params [(long)rexp->params.side_effect].se ]
+	  : idempotent_se [-(long)rexp->params.side_effect]);
+      
+    case r_alternate:
+      return
+	(   has_non_idempotent_epsilon_path (rx,
+					     rexp->params.pair.left, params)
+	 || has_non_idempotent_epsilon_path (rx,
+					     rexp->params.pair.right, params));
+
+    case r_2phase_star:
+    case r_concat:
+      return
+	(   has_non_idempotent_epsilon_path (rx,
+					     rexp->params.pair.left, params)
+	 && has_non_idempotent_epsilon_path (rx,
+					     rexp->params.pair.right, params));
+
+    case r_opt:
+      return has_non_idempotent_epsilon_path (rx,
+					      rexp->params.pair.left, params);
+    }
+
+  /* this should never happen */
+  return 0;
+}
+
+
+
+/* This computes rougly what it's name suggests.   It can (and does) go wrong 
+ * in the direction of returning spurious 0 without causing disasters.
+ */
+#ifdef __STDC__
+static int
+begins_with_complex_se (struct rx * rx, struct rexp_node * rexp)
+#else
+static int
+begins_with_complex_se (rx, rexp)
+     struct rx * rx;
+     struct rexp_node * rexp;
+#endif
+{
+  if (!rexp)
+    return 0;
+
+  switch (rexp->type)
+    {
+    case r_cset:
+    case r_data:
+      return 0;
+
+    case r_side_effect:
+      return ((long)rexp->params.side_effect >= 0);
+      
+    case r_alternate:
+      return
+	(   begins_with_complex_se (rx, rexp->params.pair.left)
+	 && begins_with_complex_se (rx, rexp->params.pair.right));
+
+
+    case r_concat:
+      return has_any_se (rx, rexp->params.pair.left);
+    case r_opt:
+    case r_star:
+    case r_2phase_star:
+      return 0;
+    }
+
+  /* this should never happen */
+  return 0;
+}
+
+
+/* This destructively removes some of the re_se_tv side effects from 
+ * a rexp tree.  In particular, during parsing re_se_tv was inserted on the
+ * right half of every | to guarantee that posix path preference could be 
+ * honored.  This function removes some which it can be determined aren't 
+ * needed.  
+ */
+
+#ifdef __STDC__
+static void
+speed_up_alt (struct rx * rx,
+	      struct rexp_node * rexp,
+	      int unposix)
+#else
+static void
+speed_up_alt (rx, rexp, unposix)
+     struct rx * rx;
+     struct rexp_node * rexp;
+     int unposix;
+#endif
+{
+  if (!rexp)
+    return;
+
+  switch (rexp->type)
+    {
+    case r_cset:
+    case r_data:
+    case r_side_effect:
+      return;
+
+    case r_opt:
+    case r_star:
+      speed_up_alt (rx, rexp->params.pair.left, unposix);
+      return;
+
+    case r_2phase_star:
+    case r_concat:
+      speed_up_alt (rx, rexp->params.pair.left, unposix);
+      speed_up_alt (rx, rexp->params.pair.right, unposix);
+      return;
+
+    case r_alternate:
+      /* the right child is guaranteed to be (concat re_se_tv <subexp>) */
+
+      speed_up_alt (rx, rexp->params.pair.left, unposix);
+      speed_up_alt (rx, rexp->params.pair.right->params.pair.right, unposix);
+      
+      if (   unposix
+	  || (begins_with_complex_se
+	      (rx, rexp->params.pair.right->params.pair.right))
+	  || !(   has_any_se (rx, rexp->params.pair.right->params.pair.right)
+	       || has_any_se (rx, rexp->params.pair.left)))
+	{
+	  struct rexp_node * conc = rexp->params.pair.right;
+	  rexp->params.pair.right = conc->params.pair.right;
+	  conc->params.pair.right = 0;
+	  rx_free_rexp (rx, conc);
+	}
+    }
+}
+
+
+
+
+
+/* `regex_compile' compiles PATTERN (of length SIZE) according to SYNTAX.
+   Returns one of error codes defined in `regex.h', or zero for success.
+
+   Assumes the `allocated' (and perhaps `buffer') and `translate'
+   fields are set in BUFP on entry.
+
+   If it succeeds, results are put in BUFP (if it returns an error, the
+   contents of BUFP are undefined):
+     `buffer' is the compiled pattern;
+     `syntax' is set to SYNTAX;
+     `used' is set to the length of the compiled pattern;
+     `fastmap_accurate' is set to zero;
+     `re_nsub' is set to the number of groups in PATTERN;
+     `not_bol' and `not_eol' are set to zero.
+   
+   The `fastmap' and `newline_anchor' fields are neither
+   examined nor set.  */
+
+
+
+#ifdef __STDC__
+RX_DECL reg_errcode_t
+rx_compile (__const__ char *pattern, int size,
+	    reg_syntax_t syntax,
+	    struct re_pattern_buffer * rxb) 
+#else
+RX_DECL reg_errcode_t
+rx_compile (pattern, size, syntax, rxb)
+     __const__ char *pattern;
+     int size;
+     reg_syntax_t syntax;
+     struct re_pattern_buffer * rxb;
+#endif
+{
+  RX_subset
+    inverse_translate [CHAR_SET_SIZE * rx_bitset_numb_subsets(CHAR_SET_SIZE)];
+  char
+    validate_inv_tr [CHAR_SET_SIZE * rx_bitset_numb_subsets(CHAR_SET_SIZE)];
+
+  /* We fetch characters from PATTERN here.  Even though PATTERN is
+     `char *' (i.e., signed), we declare these variables as unsigned, so
+     they can be reliably used as array indices.  */
+  register unsigned char c, c1;
+  
+  /* A random tempory spot in PATTERN.  */
+  __const__ char *p1;
+  
+  /* Keeps track of unclosed groups.  */
+  compile_stack_type compile_stack;
+
+  /* Points to the current (ending) position in the pattern.  */
+  __const__ char *p = pattern;
+  __const__ char *pend = pattern + size;
+  
+  /* How to translate the characters in the pattern.  */
+  unsigned char *translate = (rxb->translate
+			      ? rxb->translate
+			      : rx_id_translation);
+
+  /* When parsing is done, this will hold the expression tree. */
+  struct rexp_node * rexp = 0;
+
+  /* In the midst of compilation, this holds onto the regexp 
+   * first parst while rexp goes on to aquire additional constructs.
+   */
+  struct rexp_node * orig_rexp = 0;
+  struct rexp_node * fewer_side_effects = 0;
+
+  /* This and top_expression are saved on the compile stack. */
+  struct rexp_node ** top_expression = &rexp;
+  struct rexp_node ** last_expression = top_expression;
+  
+  /* Parameter to `goto append_node' */
+  struct rexp_node * append;
+
+  /* Counts open-groups as they are encountered.  This is the index of the
+   * innermost group being compiled.
+   */
+  regnum_t regnum = 0;
+
+  /* Place in the uncompiled pattern (i.e., the {) to
+   * which to go back if the interval is invalid.  
+   */
+  __const__ char *beg_interval;
+
+  struct re_se_params * params = 0;
+  int paramc = 0;		/* How many complex side effects so far? */
+
+  rx_side_effect side;		/* param to `goto add_side_effect' */
+
+  bzero (validate_inv_tr, sizeof (validate_inv_tr));
+
+  rxb->rx.instruction_table = rx_id_instruction_table;
+
+
+  /* Initialize the compile stack.  */
+  compile_stack.stack =  (( compile_stack_elt_t *) malloc ((INIT_COMPILE_STACK_SIZE) * sizeof ( compile_stack_elt_t)));
+  if (compile_stack.stack == 0)
+    return REG_ESPACE;
+
+  compile_stack.size = INIT_COMPILE_STACK_SIZE;
+  compile_stack.avail = 0;
+
+  /* Initialize the pattern buffer.  */
+  rxb->rx.cache = &default_cache;
+  rxb->syntax = syntax;
+  rxb->fastmap_accurate = 0;
+  rxb->not_bol = rxb->not_eol = 0;
+  rxb->least_subs = 0;
+  
+  /* Always count groups, whether or not rxb->no_sub is set.  
+   * The whole pattern is implicitly group 0, so counting begins
+   * with 1.
+   */
+  rxb->re_nsub = 0;
+
+#if !defined (emacs) && !defined (SYNTAX_TABLE)
+  /* Initialize the syntax table.  */
+   init_syntax_once ();
+#endif
+
+  /* Loop through the uncompiled pattern until we're at the end.  */
+  while (p != pend)
+    {
+      PATFETCH (c);
+
+      switch (c)
+        {
+        case '^':
+          {
+            if (   /* If at start of pattern, it's an operator.  */
+                   p == pattern + 1
+                   /* If context independent, it's an operator.  */
+                || syntax & RE_CONTEXT_INDEP_ANCHORS
+                   /* Otherwise, depends on what's come before.  */
+                || at_begline_loc_p (pattern, p, syntax))
+	      {
+		struct rexp_node * n
+		  = rx_mk_r_side_effect (&rxb->rx, (rx_side_effect)re_se_hat);
+		if (!n)
+		  return REG_ESPACE;
+		append = n;
+		goto append_node;
+	      }
+            else
+              goto normal_char;
+          }
+          break;
+
+
+        case '$':
+          {
+            if (   /* If at end of pattern, it's an operator.  */
+                   p == pend 
+                   /* If context independent, it's an operator.  */
+                || syntax & RE_CONTEXT_INDEP_ANCHORS
+                   /* Otherwise, depends on what's next.  */
+                || at_endline_loc_p (p, pend, syntax))
+	      {
+		struct rexp_node * n
+		  = rx_mk_r_side_effect (&rxb->rx, (rx_side_effect)re_se_dollar);
+		if (!n)
+		  return REG_ESPACE;
+		append = n;
+		goto append_node;
+	      }
+             else
+               goto normal_char;
+           }
+           break;
+
+
+	case '+':
+        case '?':
+          if ((syntax & RE_BK_PLUS_QM)
+              || (syntax & RE_LIMITED_OPS))
+            goto normal_char;
+
+        handle_plus:
+        case '*':
+          /* If there is no previous pattern... */
+          if (pointless_if_repeated (*last_expression, params))
+            {
+              if (syntax & RE_CONTEXT_INVALID_OPS)
+                return REG_BADRPT;
+              else if (!(syntax & RE_CONTEXT_INDEP_OPS))
+                goto normal_char;
+            }
+
+          {
+            /* 1 means zero (many) matches is allowed.  */
+            char zero_times_ok = 0, many_times_ok = 0;
+
+            /* If there is a sequence of repetition chars, collapse it
+               down to just one (the right one).  We can't combine
+               interval operators with these because of, e.g., `a{2}*',
+               which should only match an even number of `a's.  */
+
+            for (;;)
+              {
+                zero_times_ok |= c != '+';
+                many_times_ok |= c != '?';
+
+                if (p == pend)
+                  break;
+
+                PATFETCH (c);
+
+                if (c == '*'
+                    || (!(syntax & RE_BK_PLUS_QM) && (c == '+' || c == '?')))
+                  ;
+
+                else if (syntax & RE_BK_PLUS_QM  &&  c == '\\')
+                  {
+                    if (p == pend) return REG_EESCAPE;
+
+                    PATFETCH (c1);
+                    if (!(c1 == '+' || c1 == '?'))
+                      {
+                        PATUNFETCH;
+                        PATUNFETCH;
+                        break;
+                      }
+
+                    c = c1;
+                  }
+                else
+                  {
+                    PATUNFETCH;
+                    break;
+                  }
+
+                /* If we get here, we found another repeat character.  */
+               }
+
+            /* Star, etc. applied to an empty pattern is equivalent
+               to an empty pattern.  */
+            if (!last_expression)
+              break;
+
+	    /* Now we know whether or not zero matches is allowed
+	     * and also whether or not two or more matches is allowed.
+	     */
+
+	    {
+	      struct rexp_node * inner_exp = *last_expression;
+	      int need_sync = 0;
+
+	      if (many_times_ok
+		  && has_non_idempotent_epsilon_path (&rxb->rx,
+						      inner_exp, params))
+		{
+		  struct rexp_node * pusher
+		    = rx_mk_r_side_effect (&rxb->rx,
+					   (rx_side_effect)re_se_pushpos);
+		  struct rexp_node * checker
+		    = rx_mk_r_side_effect (&rxb->rx,
+					   (rx_side_effect)re_se_chkpos);
+		  struct rexp_node * pushback
+		    = rx_mk_r_side_effect (&rxb->rx,
+					   (rx_side_effect)re_se_pushback);
+		  rx_Bitset cs = rx_cset (&rxb->rx);
+		  struct rexp_node * lit_t = rx_mk_r_cset (&rxb->rx, cs);
+		  struct rexp_node * fake_state
+		    = rx_mk_r_concat (&rxb->rx, pushback, lit_t);
+		  struct rexp_node * phase2
+		    = rx_mk_r_concat (&rxb->rx, checker, fake_state);
+		  struct rexp_node * popper
+		    = rx_mk_r_side_effect (&rxb->rx,
+					   (rx_side_effect)re_se_poppos);
+		  struct rexp_node * star
+		    = rx_mk_r_2phase_star (&rxb->rx, inner_exp, phase2);
+		  struct rexp_node * a
+		    = rx_mk_r_concat (&rxb->rx, pusher, star);
+		  struct rexp_node * whole_thing
+		    = rx_mk_r_concat (&rxb->rx, a, popper);
+		  if (!(pusher && star && pushback && lit_t && fake_state
+			&& lit_t && phase2 && checker && popper
+			&& a && whole_thing))
+		    return REG_ESPACE;
+		  RX_bitset_enjoin (cs, 't');
+		  *last_expression = whole_thing;
+		}
+	      else
+		{
+		  struct rexp_node * star =
+		    (many_times_ok ? rx_mk_r_star : rx_mk_r_opt)
+		      (&rxb->rx, *last_expression);
+		  if (!star)
+		    return REG_ESPACE;
+		  *last_expression = star;
+		  need_sync = has_any_se (&rxb->rx, *last_expression);
+		}
+	      if (!zero_times_ok)
+		{
+		  struct rexp_node * concat
+		    = rx_mk_r_concat (&rxb->rx, inner_exp,
+				      rx_copy_rexp (&rxb->rx,
+						    *last_expression));
+		  if (!concat)
+		    return REG_ESPACE;
+		  *last_expression = concat;
+		}
+	      if (need_sync)
+		{
+		  int sync_se = paramc;
+		  params = (params
+			    ? ((struct re_se_params *)
+			       realloc (params,
+					sizeof (*params) * (1 + paramc)))
+			    : ((struct re_se_params *)
+			       malloc (sizeof (*params))));
+		  if (!params)
+		    return REG_ESPACE;
+		  ++paramc;
+		  params [sync_se].se = re_se_tv;
+		  side = (rx_side_effect)sync_se;
+		  goto add_side_effect;
+		}
+	    }
+	    /* The old regex.c used to optimize `.*\n'.  
+	     * Maybe rx should too?
+	     */
+	  }
+	  break;
+
+
+	case '.':
+	  {
+	    rx_Bitset cs = rx_cset (&rxb->rx);
+	    struct rexp_node * n = rx_mk_r_cset (&rxb->rx, cs);
+	    if (!(cs && n))
+	      return REG_ESPACE;
+
+	    rx_bitset_universe (rxb->rx.local_cset_size, cs);
+	    if (!(rxb->syntax & RE_DOT_NEWLINE))
+	      RX_bitset_remove (cs, '\n');
+	    if (!(rxb->syntax & RE_DOT_NOT_NULL))
+	      RX_bitset_remove (cs, 0);
+
+	    append = n;
+	    goto append_node;
+	    break;
+	  }
+
+
+        case '[':
+	  if (p == pend) return REG_EBRACK;
+          {
+            boolean had_char_class = false;
+	    rx_Bitset cs = rx_cset (&rxb->rx);
+	    struct rexp_node * node = rx_mk_r_cset (&rxb->rx, cs);
+	    int is_inverted = *p == '^';
+	    
+	    if (!(node && cs))
+	      return REG_ESPACE;
+	    
+	    /* This branch of the switch is normally exited with
+	     *`goto append_node'
+	     */
+	    append = node;
+	    
+            if (is_inverted)
+	      p++;
+	    
+            /* Remember the first position in the bracket expression.  */
+            p1 = p;
+	    
+            /* Read in characters and ranges, setting map bits.  */
+            for (;;)
+              {
+                if (p == pend) return REG_EBRACK;
+		
+                PATFETCH (c);
+		
+                /* \ might escape characters inside [...] and [^...].  */
+                if ((syntax & RE_BACKSLASH_ESCAPE_IN_LISTS) && c == '\\')
+                  {
+                    if (p == pend) return REG_EESCAPE;
+		    
+                    PATFETCH (c1);
+		    {
+		      rx_Bitset it = inverse_translation (rxb, 
+							  validate_inv_tr,
+							  inverse_translate,
+							  translate,
+							  c1);
+		      rx_bitset_union (rxb->rx.local_cset_size, cs, it);
+		    }
+                    continue;
+                  }
+		
+                /* Could be the end of the bracket expression.  If it's
+                   not (i.e., when the bracket expression is `[]' so
+                   far), the ']' character bit gets set way below.  */
+                if (c == ']' && p != p1 + 1)
+                  goto finalize_class_and_append;
+		
+                /* Look ahead to see if it's a range when the last thing
+                   was a character class.  */
+                if (had_char_class && c == '-' && *p != ']')
+                  return REG_ERANGE;
+		
+                /* Look ahead to see if it's a range when the last thing
+                   was a character: if this is a hyphen not at the
+                   beginning or the end of a list, then it's the range
+                   operator.  */
+                if (c == '-' 
+                    && !(p - 2 >= pattern && p[-2] == '[') 
+                    && !(p - 3 >= pattern && p[-3] == '[' && p[-2] == '^')
+                    && *p != ']')
+                  {
+                    reg_errcode_t ret
+                      = compile_range (rxb, cs, &p, pend, translate, syntax,
+				       inverse_translate, validate_inv_tr);
+                    if (ret != REG_NOERROR) return ret;
+                  }
+		
+                else if (p[0] == '-' && p[1] != ']')
+                  { /* This handles ranges made up of characters only.  */
+                    reg_errcode_t ret;
+		    
+		    /* Move past the `-'.  */
+                    PATFETCH (c1);
+                    
+                    ret = compile_range (rxb, cs, &p, pend, translate, syntax,
+					 inverse_translate, validate_inv_tr);
+                    if (ret != REG_NOERROR) return ret;
+                  }
+		
+                /* See if we're at the beginning of a possible character
+                   class.  */
+		
+		else if ((syntax & RE_CHAR_CLASSES)
+			 && (c == '[') && (*p == ':'))
+                  {
+                    char str[CHAR_CLASS_MAX_LENGTH + 1];
+		    
+                    PATFETCH (c);
+                    c1 = 0;
+		    
+                    /* If pattern is `[[:'.  */
+                    if (p == pend) return REG_EBRACK;
+		    
+                    for (;;)
+                      {
+                        PATFETCH (c);
+                        if (c == ':' || c == ']' || p == pend
+                            || c1 == CHAR_CLASS_MAX_LENGTH)
+			  break;
+                        str[c1++] = c;
+                      }
+                    str[c1] = '\0';
+		    
+                    /* If isn't a word bracketed by `[:' and:`]':
+                       undo the ending character, the letters, and leave 
+                       the leading `:' and `[' (but set bits for them).  */
+                    if (c == ':' && *p == ']')
+                      {
+                        int ch;
+                        boolean is_alnum = !strcmp (str, "alnum");
+                        boolean is_alpha = !strcmp (str, "alpha");
+                        boolean is_blank = !strcmp (str, "blank");
+                        boolean is_cntrl = !strcmp (str, "cntrl");
+                        boolean is_digit = !strcmp (str, "digit");
+                        boolean is_graph = !strcmp (str, "graph");
+                        boolean is_lower = !strcmp (str, "lower");
+                        boolean is_print = !strcmp (str, "print");
+                        boolean is_punct = !strcmp (str, "punct");
+                        boolean is_space = !strcmp (str, "space");
+                        boolean is_upper = !strcmp (str, "upper");
+                        boolean is_xdigit = !strcmp (str, "xdigit");
+                        
+                        if (!IS_CHAR_CLASS (str)) return REG_ECTYPE;
+			
+                        /* Throw away the ] at the end of the character
+                           class.  */
+                        PATFETCH (c);					
+			
+                        if (p == pend) return REG_EBRACK;
+			
+                        for (ch = 0; ch < 1 << CHARBITS; ch++)
+                          {
+                            if (   (is_alnum  && isalnum (ch))
+                                || (is_alpha  && isalpha (ch))
+                                || (is_blank  && isblank (ch))
+                                || (is_cntrl  && iscntrl (ch))
+                                || (is_digit  && isdigit (ch))
+                                || (is_graph  && isgraph (ch))
+                                || (is_lower  && islower (ch))
+                                || (is_print  && isprint (ch))
+                                || (is_punct  && ispunct (ch))
+                                || (is_space  && isspace (ch))
+                                || (is_upper  && isupper (ch))
+                                || (is_xdigit && isxdigit (ch)))
+			      {
+				rx_Bitset it =
+				  inverse_translation (rxb, 
+						       validate_inv_tr,
+						       inverse_translate,
+						       translate,
+						       ch);
+				rx_bitset_union (rxb->rx.local_cset_size,
+						 cs, it);
+			      }
+                          }
+                        had_char_class = true;
+                      }
+                    else
+                      {
+                        c1++;
+                        while (c1--)    
+                          PATUNFETCH;
+			{
+			  rx_Bitset it =
+			    inverse_translation (rxb, 
+						 validate_inv_tr,
+						 inverse_translate,
+						 translate,
+						 '[');
+			  rx_bitset_union (rxb->rx.local_cset_size,
+					   cs, it);
+			}
+			{
+			  rx_Bitset it =
+			    inverse_translation (rxb, 
+						 validate_inv_tr,
+						 inverse_translate,
+						 translate,
+						 ':');
+			  rx_bitset_union (rxb->rx.local_cset_size,
+					   cs, it);
+			}
+                        had_char_class = false;
+                      }
+                  }
+                else
+                  {
+                    had_char_class = false;
+		    {
+		      rx_Bitset it = inverse_translation (rxb, 
+							  validate_inv_tr,
+							  inverse_translate,
+							  translate,
+							  c);
+		      rx_bitset_union (rxb->rx.local_cset_size, cs, it);
+		    }
+                  }
+              }
+
+	  finalize_class_and_append:
+	    if (is_inverted)
+	      {
+		rx_bitset_complement (rxb->rx.local_cset_size, cs);
+		if (syntax & RE_HAT_LISTS_NOT_NEWLINE)
+		  RX_bitset_remove (cs, '\n');
+	      }
+	    goto append_node;
+          }
+          break;
+
+
+	case '(':
+          if (syntax & RE_NO_BK_PARENS)
+            goto handle_open;
+          else
+            goto normal_char;
+
+
+        case ')':
+          if (syntax & RE_NO_BK_PARENS)
+            goto handle_close;
+          else
+            goto normal_char;
+
+
+        case '\n':
+          if (syntax & RE_NEWLINE_ALT)
+            goto handle_alt;
+          else
+            goto normal_char;
+
+
+	case '|':
+          if (syntax & RE_NO_BK_VBAR)
+            goto handle_alt;
+          else
+            goto normal_char;
+
+
+        case '{':
+	  if ((syntax & RE_INTERVALS) && (syntax & RE_NO_BK_BRACES))
+	    goto handle_interval;
+	  else
+	    goto normal_char;
+
+
+        case '\\':
+          if (p == pend) return REG_EESCAPE;
+
+          /* Do not translate the character after the \, so that we can
+             distinguish, e.g., \B from \b, even if we normally would
+             translate, e.g., B to b.  */
+          PATFETCH_RAW (c);
+
+          switch (c)
+            {
+            case '(':
+              if (syntax & RE_NO_BK_PARENS)
+                goto normal_backslash;
+
+            handle_open:
+              rxb->re_nsub++;
+              regnum++;
+              if (COMPILE_STACK_FULL)
+                { 
+                  ((compile_stack.stack) =
+		   (compile_stack_elt_t *) realloc (compile_stack.stack, ( compile_stack.size << 1) * sizeof (
+													      compile_stack_elt_t)));
+                  if (compile_stack.stack == 0) return REG_ESPACE;
+
+                  compile_stack.size <<= 1;
+                }
+
+	      if (*last_expression)
+		{
+		  struct rexp_node * concat
+		    = rx_mk_r_concat (&rxb->rx, *last_expression, 0);
+		  if (!concat)
+		    return REG_ESPACE;
+		  *last_expression = concat;
+		  last_expression = &concat->params.pair.right;
+		}
+
+              /*
+	       * These are the values to restore when we hit end of this
+               * group.  
+	       */
+	      COMPILE_STACK_TOP.top_expression = top_expression;
+	      COMPILE_STACK_TOP.last_expression = last_expression;
+              COMPILE_STACK_TOP.regnum = regnum;
+	      
+              compile_stack.avail++;
+	      
+	      top_expression = last_expression;
+	      break;
+
+
+            case ')':
+              if (syntax & RE_NO_BK_PARENS) goto normal_backslash;
+
+            handle_close:
+              /* See similar code for backslashed left paren above.  */
+              if (COMPILE_STACK_EMPTY)
+                if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
+                  goto normal_char;
+                else
+                  return REG_ERPAREN;
+
+              /* Since we just checked for an empty stack above, this
+                 ``can't happen''.  */
+
+              {
+                /* We don't just want to restore into `regnum', because
+                   later groups should continue to be numbered higher,
+                   as in `(ab)c(de)' -- the second group is #2.  */
+                regnum_t this_group_regnum;
+		struct rexp_node ** inner = top_expression;
+
+                compile_stack.avail--;
+		top_expression = COMPILE_STACK_TOP.top_expression;
+		last_expression = COMPILE_STACK_TOP.last_expression;
+                this_group_regnum = COMPILE_STACK_TOP.regnum;
+		{
+		  int left_se = paramc;
+		  int right_se = paramc + 1;
+
+		  params = (params
+			    ? ((struct re_se_params *)
+			       realloc (params,
+					(paramc + 2) * sizeof (params[0])))
+			    : ((struct re_se_params *)
+			       malloc (2 * sizeof (params[0]))));
+		  if (!params)
+		    return REG_ESPACE;
+		  paramc += 2;
+
+		  params[left_se].se = re_se_lparen;
+		  params[left_se].op1 = this_group_regnum;
+		  params[right_se].se = re_se_rparen;
+		  params[right_se].op1 = this_group_regnum;
+		  {
+		    struct rexp_node * left
+		      = rx_mk_r_side_effect (&rxb->rx,
+					     (rx_side_effect)left_se);
+		    struct rexp_node * right
+		      = rx_mk_r_side_effect (&rxb->rx,
+					     (rx_side_effect)right_se);
+		    struct rexp_node * c1
+		      = (*inner
+			 ? rx_mk_r_concat (&rxb->rx, left, *inner) : left);
+		    struct rexp_node * c2
+		      = rx_mk_r_concat (&rxb->rx, c1, right);
+		    if (!(left && right && c1 && c2))
+		      return REG_ESPACE;
+		    *inner = c2;
+		  }
+		}
+		break;
+	      }
+
+            case '|':					/* `\|'.  */
+              if ((syntax & RE_LIMITED_OPS) || (syntax & RE_NO_BK_VBAR))
+                goto normal_backslash;
+            handle_alt:
+              if (syntax & RE_LIMITED_OPS)
+                goto normal_char;
+
+	      {
+		struct rexp_node * alt
+		  = rx_mk_r_alternate (&rxb->rx, *top_expression, 0);
+		if (!alt)
+		  return REG_ESPACE;
+		*top_expression = alt;
+		last_expression = &alt->params.pair.right;
+		{
+		  int sync_se = paramc;
+
+		  params = (params
+			    ? ((struct re_se_params *)
+			       realloc (params,
+					(paramc + 1) * sizeof (params[0])))
+			    : ((struct re_se_params *)
+			       malloc (sizeof (params[0]))));
+		  if (!params)
+		    return REG_ESPACE;
+		  ++paramc;
+
+		  params[sync_se].se = re_se_tv;
+		  {
+		    struct rexp_node * sync
+		      = rx_mk_r_side_effect (&rxb->rx,
+					     (rx_side_effect)sync_se);
+		    struct rexp_node * conc
+		      = rx_mk_r_concat (&rxb->rx, sync, 0);
+
+		    if (!sync || !conc)
+		      return REG_ESPACE;
+
+		    *last_expression = conc;
+		    last_expression = &conc->params.pair.right;
+		  }
+		}
+	      }
+              break;
+
+
+            case '{': 
+              /* If \{ is a literal.  */
+              if (!(syntax & RE_INTERVALS)
+                     /* If we're at `\{' and it's not the open-interval 
+                        operator.  */
+                  || ((syntax & RE_INTERVALS) && (syntax & RE_NO_BK_BRACES))
+                  || (p - 2 == pattern  &&  p == pend))
+                goto normal_backslash;
+
+            handle_interval:
+              {
+                /* If got here, then the syntax allows intervals.  */
+
+                /* At least (most) this many matches must be made.  */
+                int lower_bound = -1, upper_bound = -1;
+
+                beg_interval = p - 1;
+
+                if (p == pend)
+                  {
+                    if (syntax & RE_NO_BK_BRACES)
+                      goto unfetch_interval;
+                    else
+                      return REG_EBRACE;
+                  }
+
+                GET_UNSIGNED_NUMBER (lower_bound);
+
+                if (c == ',')
+                  {
+                    GET_UNSIGNED_NUMBER (upper_bound);
+                    if (upper_bound < 0) upper_bound = RE_DUP_MAX;
+                  }
+                else
+                  /* Interval such as `{1}' => match exactly once. */
+                  upper_bound = lower_bound;
+
+                if (lower_bound < 0 || upper_bound > RE_DUP_MAX
+                    || lower_bound > upper_bound)
+                  {
+                    if (syntax & RE_NO_BK_BRACES)
+                      goto unfetch_interval;
+                    else 
+                      return REG_BADBR;
+                  }
+
+                if (!(syntax & RE_NO_BK_BRACES)) 
+                  {
+                    if (c != '\\') return REG_EBRACE;
+                    PATFETCH (c);
+                  }
+
+                if (c != '}')
+                  {
+                    if (syntax & RE_NO_BK_BRACES)
+                      goto unfetch_interval;
+                    else 
+                      return REG_BADBR;
+                  }
+
+                /* We just parsed a valid interval.  */
+
+                /* If it's invalid to have no preceding re.  */
+                if (pointless_if_repeated (*last_expression, params))
+                  {
+                    if (syntax & RE_CONTEXT_INVALID_OPS)
+                      return REG_BADRPT;
+                    else if (!(syntax & RE_CONTEXT_INDEP_OPS))
+                      goto unfetch_interval;
+		    /* was: else laststart = b; */
+                  }
+
+                /* If the upper bound is zero, don't want to iterate
+                 * at all.
+		 */
+                 if (upper_bound == 0)
+		   {
+		     if (*last_expression)
+		       {
+			 rx_free_rexp (&rxb->rx, *last_expression);
+			 *last_expression = 0;
+		       }
+		   }
+		else
+		  /* Otherwise, we have a nontrivial interval. */
+		  {
+		    int iter_se = paramc;
+		    int end_se = paramc + 1;
+		    params = (params
+			      ? ((struct re_se_params *)
+				 realloc (params,
+					  sizeof (*params) * (2 + paramc)))
+			      : ((struct re_se_params *)
+				 malloc (2 * sizeof (*params))));
+		    if (!params)
+		      return REG_ESPACE;
+		    paramc += 2;
+		    params [iter_se].se = re_se_iter;
+		    params [iter_se].op1 = lower_bound;
+		    params[iter_se].op2 = upper_bound;
+
+		    params[end_se].se = re_se_end_iter;
+		    params[end_se].op1 = lower_bound;
+		    params[end_se].op2 = upper_bound;
+		    {
+		      struct rexp_node * push0
+			= rx_mk_r_side_effect (&rxb->rx,
+					       (rx_side_effect)re_se_push0);
+		      struct rexp_node * start_one_iter
+			= rx_mk_r_side_effect (&rxb->rx,
+					       (rx_side_effect)iter_se);
+		      struct rexp_node * phase1
+			= rx_mk_r_concat (&rxb->rx, start_one_iter,
+					  *last_expression);
+		      struct rexp_node * pushback
+			= rx_mk_r_side_effect (&rxb->rx,
+					       (rx_side_effect)re_se_pushback);
+		      rx_Bitset cs = rx_cset (&rxb->rx);
+		      struct rexp_node * lit_t
+			= rx_mk_r_cset (&rxb->rx, cs);
+		      struct rexp_node * phase2
+			= rx_mk_r_concat (&rxb->rx, pushback, lit_t);
+		      struct rexp_node * loop
+			= rx_mk_r_2phase_star (&rxb->rx, phase1, phase2);
+		      struct rexp_node * push_n_loop
+			= rx_mk_r_concat (&rxb->rx, push0, loop);
+		      struct rexp_node * final_test
+			= rx_mk_r_side_effect (&rxb->rx,
+					       (rx_side_effect)end_se);
+		      struct rexp_node * full_exp
+			= rx_mk_r_concat (&rxb->rx, push_n_loop, final_test);
+
+		      if (!(push0 && start_one_iter && phase1
+			    && pushback && lit_t && phase2
+			    && loop && push_n_loop && final_test && full_exp))
+			return REG_ESPACE;
+
+		      RX_bitset_enjoin(cs, 't');
+
+		      *last_expression = full_exp;
+		    }
+		  }
+                beg_interval = 0;
+              }
+              break;
+
+            unfetch_interval:
+              /* If an invalid interval, match the characters as literals.  */
+               p = beg_interval;
+               beg_interval = 0;
+
+               /* normal_char and normal_backslash need `c'.  */
+               PATFETCH (c);	
+
+               if (!(syntax & RE_NO_BK_BRACES))
+                 {
+                   if (p > pattern  &&  p[-1] == '\\')
+                     goto normal_backslash;
+                 }
+               goto normal_char;
+
+#ifdef emacs
+            /* There is no way to specify the before_dot and after_dot
+               operators.  rms says this is ok.  --karl  */
+            case '=':
+	      side = (rx_side_effect)rx_se_at_dot;
+	      goto add_side_effect;
+              break;
+
+            case 's':
+	    case 'S':
+	      {
+		rx_Bitset cs = rx_cset (&rxb->rx);
+		struct rexp_node * set = rx_mk_r_cset (&rxb->rx, cs);
+		if (!(cs && set))
+		  return REG_ESPACE;
+		if (c == 'S')
+		  rx_bitset_universe (rxb->rx.local_cset_size, cs);
+
+		PATFETCH (c);
+		{
+		  int x;
+		  enum syntaxcode code = syntax_spec_code [c];
+		  for (x = 0; x < 256; ++x)
+		    {
+		      
+		      if (SYNTAX (x) == code)
+			{
+			  rx_Bitset it =
+			    inverse_translation (rxb, validate_inv_tr,
+						 inverse_translate,
+						 translate, x);
+			  rx_bitset_xor (rxb->rx.local_cset_size, cs, it);
+			}
+		    }
+		}
+		append = set;
+		goto append_node;
+	      }
+              break;
+#endif /* emacs */
+
+
+            case 'w':
+            case 'W':
+	      {
+		rx_Bitset cs = rx_cset (&rxb->rx);
+		struct rexp_node * n = (cs ? rx_mk_r_cset (&rxb->rx, cs) : 0);
+		if (!(cs && n))
+		  return REG_ESPACE;
+		if (c == 'W')
+		  rx_bitset_universe (rxb->rx.local_cset_size ,cs);
+		{
+		  int x;
+		  for (x = rxb->rx.local_cset_size - 1; x > 0; --x)
+		    if (SYNTAX(x) & Sword)
+		      RX_bitset_toggle (cs, x);
+		}
+		append = n;
+		goto append_node;
+	      }
+              break;
+
+/* With a little extra work, some of these side effects could be optimized
+ * away (basicly by looking at what we already know about the surrounding
+ * chars).  
+ */
+            case '<':
+	      side = (rx_side_effect)re_se_wordbeg;
+	      goto add_side_effect;
+              break;
+
+            case '>':
+              side = (rx_side_effect)re_se_wordend;
+	      goto add_side_effect;
+              break;
+
+            case 'b':
+              side = (rx_side_effect)re_se_wordbound;
+	      goto add_side_effect;
+              break;
+
+            case 'B':
+              side = (rx_side_effect)re_se_notwordbound;
+	      goto add_side_effect;
+              break;
+
+            case '`':
+	      side = (rx_side_effect)re_se_begbuf;
+	      goto add_side_effect;
+	      break;
+	      
+            case '\'':
+	      side = (rx_side_effect)re_se_endbuf;
+	      goto add_side_effect;
+              break;
+
+	    add_side_effect:
+	      {
+		struct rexp_node * se
+		  = rx_mk_r_side_effect (&rxb->rx, side);
+		if (!se)
+		  return REG_ESPACE;
+		append = se;
+		goto append_node;
+	      }
+	      break;
+
+            case '1': case '2': case '3': case '4': case '5':
+            case '6': case '7': case '8': case '9':
+              if (syntax & RE_NO_BK_REFS)
+                goto normal_char;
+
+              c1 = c - '0';
+
+              if (c1 > regnum)
+                return REG_ESUBREG;
+
+              /* Can't back reference to a subexpression if inside of it.  */
+              if (group_in_compile_stack (compile_stack, c1))
+		return REG_ESUBREG;
+
+	      {
+		int backref_se = paramc;
+		params = (params
+			  ? ((struct re_se_params *)
+			     realloc (params,
+				      sizeof (*params) * (1 + paramc)))
+			  : ((struct re_se_params *)
+			     malloc (sizeof (*params))));
+		if (!params)
+		  return REG_ESPACE;
+		++paramc;
+		params[backref_se].se = re_se_backref;
+		params[backref_se].op1 = c1;
+		side = (rx_side_effect)backref_se;
+		goto add_side_effect;
+	      }
+              break;
+
+            case '+':
+            case '?':
+              if (syntax & RE_BK_PLUS_QM)
+                goto handle_plus;
+              else
+                goto normal_backslash;
+
+            default:
+            normal_backslash:
+              /* You might think it would be useful for \ to mean
+                 not to translate; but if we don't translate it
+                 it will never match anything.  */
+              c = TRANSLATE (c);
+              goto normal_char;
+            }
+          break;
+
+
+	default:
+        /* Expects the character in `c'.  */
+	normal_char:
+	    {
+	      rx_Bitset cs = rx_cset(&rxb->rx);
+	      struct rexp_node * match = rx_mk_r_cset (&rxb->rx, cs);
+	      rx_Bitset it;
+	      if (!(cs && match))
+		return REG_ESPACE;
+	      it = inverse_translation (rxb, validate_inv_tr,
+					inverse_translate, translate, c);
+	      rx_bitset_union (CHAR_SET_SIZE, cs, it);
+	      append = match;
+
+	    append_node:
+	      /* This genericly appends the rexp APPEND to *LAST_EXPRESSION
+	       * and then parses the next character normally.
+	       */
+	      if (*last_expression)
+		{
+		  struct rexp_node * concat
+		    = rx_mk_r_concat (&rxb->rx, *last_expression, append);
+		  if (!concat)
+		    return REG_ESPACE;
+		  *last_expression = concat;
+		  last_expression = &concat->params.pair.right;
+		}
+	      else
+		*last_expression = append;
+	    }
+	} /* switch (c) */
+    } /* while p != pend */
+
+  
+  {
+    int win_se = paramc;
+    params = (params
+	      ? ((struct re_se_params *)
+		 realloc (params,
+			  sizeof (*params) * (1 + paramc)))
+	      : ((struct re_se_params *)
+		 malloc (sizeof (*params))));
+    if (!params)
+      return REG_ESPACE;
+    ++paramc;
+    params[win_se].se = re_se_win;
+    {
+      struct rexp_node * se
+	= rx_mk_r_side_effect (&rxb->rx, (rx_side_effect)win_se);
+      struct rexp_node * concat
+	= rx_mk_r_concat (&rxb->rx, rexp, se);
+      if (!(se && concat))
+	return REG_ESPACE;
+      rexp = concat;
+    }
+  }
+
+
+  /* Through the pattern now.  */
+
+  if (!COMPILE_STACK_EMPTY) 
+    return REG_EPAREN;
+
+      free (compile_stack.stack);
+
+  orig_rexp = rexp;
+#ifdef RX_DEBUG
+  if (rx_debug_compile)
+    {
+      dbug_rxb = rxb;
+      fputs ("\n\nCompiling ", stdout);
+      fwrite (pattern, 1, size, stdout);
+      fputs (":\n", stdout);
+      rxb->se_params = params;
+      print_rexp (&rxb->rx, orig_rexp, 2, re_seprint, stdout);
+    }
+#endif
+  {
+    rx_Bitset cs = rx_cset(&rxb->rx);
+    rx_Bitset cs2 = rx_cset(&rxb->rx);
+    char * se_map = (char *) alloca (paramc);
+    struct rexp_node * new_rexp = 0;
+
+
+    bzero (se_map, paramc);
+    find_backrefs (se_map, rexp, params);
+    fewer_side_effects =
+      remove_unecessary_side_effects (&rxb->rx, se_map,
+				      rx_copy_rexp (&rxb->rx, rexp), params);
+
+    speed_up_alt (&rxb->rx, rexp, 0);
+    speed_up_alt (&rxb->rx, fewer_side_effects, 1);
+
+    {
+      char * syntax_parens = rxb->syntax_parens;
+      if (syntax_parens == (char *)0x1)
+	rexp = remove_unecessary_side_effects
+	  (&rxb->rx, se_map, rexp, params);
+      else if (syntax_parens)
+	{
+	  int x;
+	  for (x = 0; x < paramc; ++x)
+	    if ((   (params[x].se == re_se_lparen)
+		 || (params[x].se == re_se_rparen))
+		&& (!syntax_parens [params[x].op1]))
+	      se_map [x] = 1;
+	  rexp = remove_unecessary_side_effects
+	    (&rxb->rx, se_map, rexp, params);
+	}
+    }
+
+    /* At least one more optimization would be nice to have here but i ran out 
+     * of time.  The idea would be to delay side effects.  
+     * For examle, `(abc)' is the same thing as `abc()' except that the
+     * left paren is offset by 3 (which we know at compile time).
+     * (In this comment, write that second pattern `abc(:3:)' 
+     * where `(:3:' is a syntactic unit.)
+     *
+     * Trickier:  `(abc|defg)'  is the same as `(abc(:3:|defg(:4:))'
+     * (The paren nesting may be hard to follow -- that's an alternation
+     *	of `abc(:3:' and `defg(:4:' inside (purely syntactic) parens
+     *  followed by the closing paren from the original expression.)
+     *
+     * Neither the expression tree representation nor the the nfa make
+     * this very easy to write. :(
+     */
+
+  /* What we compile is different than what the parser returns.
+   * Suppose the parser returns expression R.
+   * Let R' be R with unnecessary register assignments removed 
+   * (see REMOVE_UNECESSARY_SIDE_EFFECTS, above).
+   *
+   * What we will compile is the expression:
+   *
+   *    m{try}R{win}\|s{try}R'{win}
+   *
+   * {try} and {win} denote side effect epsilons (see EXPLORE_FUTURE).
+   * 
+   * When trying a match, we insert an `m' at the beginning of the 
+   * string if the user wants registers to be filled, `s' if not.
+   */
+    new_rexp =
+      rx_mk_r_alternate
+	(&rxb->rx,
+	 rx_mk_r_concat (&rxb->rx, rx_mk_r_cset (&rxb->rx, cs2), rexp),
+	 rx_mk_r_concat (&rxb->rx,
+			 rx_mk_r_cset (&rxb->rx, cs), fewer_side_effects));
+
+    if (!(new_rexp && cs && cs2))
+      return REG_ESPACE;
+    RX_bitset_enjoin (cs2, '\0'); /* prefixed to the rexp used for matching. */
+    RX_bitset_enjoin (cs, '\1'); /* prefixed to the rexp used for searching. */
+    rexp = new_rexp;
+  }
+
+#ifdef RX_DEBUG
+  if (rx_debug_compile)
+    {
+      fputs ("\n...which is compiled as:\n", stdout);
+      print_rexp (&rxb->rx, rexp, 2, re_seprint, stdout);
+    }
+#endif
+  {
+    struct rx_nfa_state *start = 0;
+    struct rx_nfa_state *end = 0;
+
+    if (!rx_build_nfa (&rxb->rx, rexp, &start, &end))
+      return REG_ESPACE;	/*  */
+    else
+      {
+	void * mem = (void *)rxb->buffer;
+	unsigned long size = rxb->allocated;
+	int start_id;
+	char * perm_mem;
+	int iterator_size = paramc * sizeof (params[0]);
+
+	end->is_final = 1;
+	start->is_start = 1;
+	rx_name_nfa_states (&rxb->rx);
+	start_id = start->id;
+#ifdef RX_DEBUG
+	if (rx_debug_compile)
+	  {
+	    fputs ("...giving the NFA: \n", stdout);
+	    dbug_rxb = rxb;
+	    print_nfa (&rxb->rx, rxb->rx.nfa_states, re_seprint, stdout);
+	  }
+#endif
+	if (!rx_eclose_nfa (&rxb->rx))
+	  return REG_ESPACE;
+	else
+	  {
+	    rx_delete_epsilon_transitions (&rxb->rx);
+	    
+	    /* For compatability reasons, we need to shove the
+	     * compiled nfa into one chunk of malloced memory.
+	     */
+	    rxb->rx.reserved = (   sizeof (params[0]) * paramc
+				+  rx_sizeof_bitset (rxb->rx.local_cset_size));
+#ifdef RX_DEBUG
+	    if (rx_debug_compile)
+	      {
+		dbug_rxb = rxb;
+		fputs ("...which cooks down (uncompactified) to: \n", stdout);
+		print_nfa (&rxb->rx, rxb->rx.nfa_states, re_seprint, stdout);
+	      }
+#endif
+	    if (!rx_compactify_nfa (&rxb->rx, &mem, &size))
+	      return REG_ESPACE;
+	    rxb->buffer = mem;
+	    rxb->allocated = size;
+	    rxb->rx.buffer = mem;
+	    rxb->rx.allocated = size;
+	    perm_mem = ((char *)rxb->rx.buffer
+			+ rxb->rx.allocated - rxb->rx.reserved);
+	    rxb->se_params = ((struct re_se_params *)perm_mem);
+	    bcopy (params, rxb->se_params, iterator_size);
+	    perm_mem += iterator_size;
+	    rxb->fastset = (rx_Bitset) perm_mem;
+	    rxb->start = rx_id_to_nfa_state (&rxb->rx, start_id);
+	  }
+	rx_bitset_null (rxb->rx.local_cset_size, rxb->fastset);
+	rxb->can_match_empty = compute_fastset (rxb, orig_rexp);
+	rxb->match_regs_on_stack =
+	  registers_on_stack (rxb, orig_rexp, 0, params); 
+	rxb->search_regs_on_stack =
+	  registers_on_stack (rxb, fewer_side_effects, 0, params);
+	if (rxb->can_match_empty)
+	  rx_bitset_universe (rxb->rx.local_cset_size, rxb->fastset);
+	rxb->is_anchored = is_anchored (orig_rexp, (rx_side_effect) re_se_hat);
+	rxb->begbuf_only = is_anchored (orig_rexp,
+					(rx_side_effect) re_se_begbuf);
+      }
+    rx_free_rexp (&rxb->rx, rexp);
+    if (params)
+      free (params);
+#ifdef RX_DEBUG
+    if (rx_debug_compile)
+      {
+	dbug_rxb = rxb;
+	fputs ("...which cooks down to: \n", stdout);
+	print_nfa (&rxb->rx, rxb->rx.nfa_states, re_seprint, stdout);
+      }
+#endif
+  }
+  return REG_NOERROR;
+}
+
+
+
+/* This table gives an error message for each of the error codes listed
+   in regex.h.  Obviously the order here has to be same as there.  */
+
+__const__ char * rx_error_msg[] =
+{ 0,						/* REG_NOERROR */
+    "No match",					/* REG_NOMATCH */
+    "Invalid regular expression",		/* REG_BADPAT */
+    "Invalid collation character",		/* REG_ECOLLATE */
+    "Invalid character class name",		/* REG_ECTYPE */
+    "Trailing backslash",			/* REG_EESCAPE */
+    "Invalid back reference",			/* REG_ESUBREG */
+    "Unmatched [ or [^",			/* REG_EBRACK */
+    "Unmatched ( or \\(",			/* REG_EPAREN */
+    "Unmatched \\{",				/* REG_EBRACE */
+    "Invalid content of \\{\\}",		/* REG_BADBR */
+    "Invalid range end",			/* REG_ERANGE */
+    "Memory exhausted",				/* REG_ESPACE */
+    "Invalid preceding regular expression",	/* REG_BADRPT */
+    "Premature end of regular expression",	/* REG_EEND */
+    "Regular expression too big",		/* REG_ESIZE */
+    "Unmatched ) or \\)",			/* REG_ERPAREN */
+};
+
+
+
+
+char rx_slowmap [256] =
+{
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+};
+
+#ifdef __STDC__
+RX_DECL void
+rx_blow_up_fastmap (struct re_pattern_buffer * rxb)
+#else
+RX_DECL void
+rx_blow_up_fastmap (rxb)
+     struct re_pattern_buffer * rxb;
+#endif
+{
+  int x;
+  for (x = 0; x < 256; ++x)	/* &&&& 3.6 % */
+    rxb->fastmap [x] = !!RX_bitset_member (rxb->fastset, x);
+  rxb->fastmap_accurate = 1;
+}
+
+
+
+
+#if !defined(REGEX_MALLOC) && !defined(__GNUC__)
+#define RE_SEARCH_2_FN	inner_re_search_2
+#define RE_S2_QUAL static
+#else
+#define RE_SEARCH_2_FN	re_search_2
+#define RE_S2_QUAL 
+#endif
+
+struct re_search_2_closure
+{
+  __const__ char * string1;
+  int size1;
+  __const__ char * string2;
+  int size2;
+};
+
+
+static __inline__ enum rx_get_burst_return
+re_search_2_get_burst (pos, vclosure, stop)
+     struct rx_string_position * pos;
+     void * vclosure;
+     int stop;
+{
+  struct re_search_2_closure * closure;
+  closure = (struct re_search_2_closure *)vclosure;
+  if (!closure->string2)
+    {
+      int inset;
+
+      inset = pos->pos - pos->string;
+      if ((inset < -1) || (inset > closure->size1))
+	return rx_get_burst_no_more;
+      else
+	{
+	  pos->pos = (__const__ unsigned char *) closure->string1 + inset;
+	  pos->string = (__const__ unsigned char *) closure->string1;
+	  pos->size = closure->size1;
+	  pos->end = ((__const__ unsigned char *)
+		      MIN(closure->string1 + closure->size1,
+			  closure->string1 + stop));
+	  pos->offset = 0;
+	  return ((pos->pos < pos->end)
+		  ? rx_get_burst_ok
+		  :  rx_get_burst_no_more);
+	}
+    }
+  else if (!closure->string1)
+    {
+      int inset;
+
+      inset = pos->pos - pos->string;
+      pos->pos = (__const__ unsigned char *) closure->string2 + inset;
+      pos->string = (__const__ unsigned char *) closure->string2;
+      pos->size = closure->size2;
+      pos->end = ((__const__ unsigned char *)
+		  MIN(closure->string2 + closure->size2,
+		      closure->string2 + stop));
+      pos->offset = 0;
+      return ((pos->pos < pos->end)
+	      ? rx_get_burst_ok
+	      :  rx_get_burst_no_more);
+    }
+  else
+    {
+      int inset;
+
+      inset = pos->pos - pos->string + pos->offset;
+      if (inset < closure->size1)
+	{
+	  pos->pos = (__const__ unsigned char *) closure->string1 + inset;
+	  pos->string = (__const__ unsigned char *) closure->string1;
+	  pos->size = closure->size1;
+	  pos->end = ((__const__ unsigned char *)
+		      MIN(closure->string1 + closure->size1,
+			  closure->string1 + stop));
+	  pos->offset = 0;
+	  return rx_get_burst_ok;
+	}
+      else
+	{
+	  pos->pos = ((__const__ unsigned char *)
+		      closure->string2 + inset - closure->size1);
+	  pos->string = (__const__ unsigned char *) closure->string2;
+	  pos->size = closure->size2;
+	  pos->end = ((__const__ unsigned char *)
+		      MIN(closure->string2 + closure->size2,
+			  closure->string2 + stop - closure->size1));
+	  pos->offset = closure->size1;
+	  return ((pos->pos < pos->end)
+		  ? rx_get_burst_ok
+		  :  rx_get_burst_no_more);
+	}
+    }
+}
+
+
+static __inline__ enum rx_back_check_return
+re_search_2_back_check (pos, lparen, rparen, translate, vclosure, stop)
+     struct rx_string_position * pos;
+     int lparen;
+     int rparen;
+     unsigned char * translate;
+     void * vclosure;
+     int stop;
+{
+  struct rx_string_position there;
+  struct rx_string_position past;
+
+  there = *pos;
+  there.pos = there.string + lparen - there.offset;
+  re_search_2_get_burst (&there, vclosure, stop);
+
+  past = *pos;
+  past.pos = past.string + rparen - there.offset;
+  re_search_2_get_burst (&past, vclosure, stop);
+
+  ++pos->pos;
+  re_search_2_get_burst (pos, vclosure, stop);
+
+  while (   (there.pos != past.pos)
+	 && (pos->pos != pos->end))
+    if (TRANSLATE(*there.pos) != TRANSLATE(*pos->pos))
+      return rx_back_check_fail;
+    else
+      {
+	++there.pos;
+	++pos->pos;
+	if (there.pos == there.end)
+	  re_search_2_get_burst (&there, vclosure, stop);
+	if (pos->pos == pos->end)
+	  re_search_2_get_burst (pos, vclosure, stop);
+      }
+
+  if (there.pos != past.pos)
+    return rx_back_check_fail;
+  --pos->pos;
+  re_search_2_get_burst (pos, vclosure, stop);
+  return rx_back_check_pass;
+}
+
+static __inline__ int
+re_search_2_fetch_char (pos, offset, app_closure, stop)
+     struct rx_string_position * pos;
+     int offset;
+     void * app_closure;
+     int stop;
+{
+  struct re_search_2_closure * closure;
+  closure = (struct re_search_2_closure *)app_closure;
+  if (offset == 0)
+    {
+      if (pos->pos >= pos->string)
+	return *pos->pos;
+      else
+	{
+	  if (   (pos->string == (__const__ unsigned char *) closure->string2)
+	      && (closure->string1)
+	      && (closure->size1))
+	    return closure->string1[closure->size1 - 1];
+	  else
+	    return 0;		/* sure, why not. */
+	}
+    }
+  if (pos->pos == pos->end)
+    return *closure->string2;
+  else
+    return pos->pos[1];
+}
+     
+
+#ifdef __STDC__
+RE_S2_QUAL int
+RE_SEARCH_2_FN (struct re_pattern_buffer *rxb,
+		__const__ char * string1, int size1,
+		__const__ char * string2, int size2,
+		int startpos, int range,
+		struct re_registers *regs,
+		int stop)
+#else
+RE_S2_QUAL int
+RE_SEARCH_2_FN (rxb,
+		string1, size1, string2, size2, startpos, range, regs, stop)
+     struct re_pattern_buffer *rxb;
+     __const__ char * string1;
+     int size1;
+     __const__ char * string2;
+     int size2;
+     int startpos;
+     int range;
+     struct re_registers *regs;
+     int stop;
+#endif
+{
+  int answer;
+  struct re_search_2_closure closure;
+  closure.string1 = string1;
+  closure.size1 = size1;
+  closure.string2 = string2;
+  closure.size2 = size2;
+  answer = rx_search (rxb, startpos, range, stop, size1 + size2,
+		      re_search_2_get_burst,
+		      re_search_2_back_check,
+		      re_search_2_fetch_char,
+		      (void *)&closure,
+		      regs,
+		      0,
+		      0);
+  switch (answer)
+    {
+    case rx_search_continuation:
+      abort ();
+    case rx_search_error:
+      return -2;
+    case rx_search_soft_fail:
+    case rx_search_fail:
+      return -1;
+    default:
+      return answer;
+    }
+}
+
+/* Export rx_search to callers outside this file.  */
+
+int
+re_rx_search (rxb, startpos, range, stop, total_size,
+	      get_burst, back_check, fetch_char,
+	      app_closure, regs, resume_state, save_state)
+     struct re_pattern_buffer * rxb;
+     int startpos;
+     int range;
+     int stop;
+     int total_size;
+     rx_get_burst_fn get_burst;
+     rx_back_check_fn back_check;
+     rx_fetch_char_fn fetch_char;
+     void * app_closure;
+     struct re_registers * regs;
+     struct rx_search_state * resume_state;
+     struct rx_search_state * save_state;
+{
+  return rx_search (rxb, startpos, range, stop, total_size,
+		    get_burst, back_check, fetch_char, app_closure,
+		    regs, resume_state, save_state);
+}
+
+#if !defined(REGEX_MALLOC) && !defined(__GNUC__)
+#ifdef __STDC__
+int
+re_search_2 (struct re_pattern_buffer *rxb,
+	     __const__ char * string1, int size1,
+	     __const__ char * string2, int size2,
+	     int startpos, int range,
+	     struct re_registers *regs,
+	     int stop)
+#else
+int
+re_search_2 (rxb, string1, size1, string2, size2, startpos, range, regs, stop)
+     struct re_pattern_buffer *rxb;
+     __const__ char * string1;
+     int size1;
+     __const__ char * string2;
+     int size2;
+     int startpos;
+     int range;
+     struct re_registers *regs;
+     int stop;
+#endif
+{
+  int ret;
+  ret = inner_re_search_2 (rxb, string1, size1, string2, size2, startpos,
+			   range, regs, stop);
+  alloca (0);
+  return ret;
+}
+#endif
+
+
+/* Like re_search_2, above, but only one string is specified, and
+ * doesn't let you say where to stop matching.
+ */
+
+#ifdef __STDC__
+int
+re_search (struct re_pattern_buffer * rxb, __const__ char *string,
+	   int size, int startpos, int range,
+	   struct re_registers *regs)
+#else
+int
+re_search (rxb, string, size, startpos, range, regs)
+     struct re_pattern_buffer * rxb;
+     __const__ char * string;
+     int size;
+     int startpos;
+     int range;
+     struct re_registers *regs;
+#endif
+{
+  return re_search_2 (rxb, 0, 0, string, size, startpos, range, regs, size);
+}
+
+#ifdef __STDC__
+int
+re_match_2 (struct re_pattern_buffer * rxb,
+	    __const__ char * string1, int size1,
+	    __const__ char * string2, int size2,
+	    int pos, struct re_registers *regs, int stop)
+#else
+int
+re_match_2 (rxb, string1, size1, string2, size2, pos, regs, stop)
+     struct re_pattern_buffer * rxb;
+     __const__ char * string1;
+     int size1;
+     __const__ char * string2;
+     int size2;
+     int pos;
+     struct re_registers *regs;
+     int stop;
+#endif
+{
+  struct re_registers some_regs;
+  regoff_t start;
+  regoff_t end;
+  int srch;
+  int save = rxb->regs_allocated;
+  struct re_registers * regs_to_pass = regs;
+
+  if (!regs)
+    {
+      some_regs.start = &start;
+      some_regs.end = &end;
+      some_regs.num_regs = 1;
+      regs_to_pass = &some_regs;
+      rxb->regs_allocated = REGS_FIXED;
+    }
+
+  srch = re_search_2 (rxb, string1, size1, string2, size2,
+		      pos, 1, regs_to_pass, stop);
+  if (regs_to_pass != regs)
+    rxb->regs_allocated = save;
+  if (srch < 0)
+    return srch;
+  return regs_to_pass->end[0] - regs_to_pass->start[0];
+}
+
+/* re_match is like re_match_2 except it takes only a single string.  */
+
+#ifdef __STDC__
+int
+re_match (struct re_pattern_buffer * rxb,
+	  __const__ char * string,
+	  int size, int pos,
+	  struct re_registers *regs)
+#else
+int
+re_match (rxb, string, size, pos, regs)
+     struct re_pattern_buffer * rxb;
+     __const__ char *string;
+     int size;
+     int pos;
+     struct re_registers *regs;
+#endif
+{
+  return re_match_2 (rxb, string, size, 0, 0, pos, regs, size);
+}
+
+
+
+/* Set by `re_set_syntax' to the current regexp syntax to recognize.  Can
+   also be assigned to arbitrarily: each pattern buffer stores its own
+   syntax, so it can be changed between regex compilations.  */
+reg_syntax_t re_syntax_options = RE_SYNTAX_EMACS;
+
+
+/* Specify the precise syntax of regexps for compilation.  This provides
+   for compatibility for various utilities which historically have
+   different, incompatible syntaxes.
+
+   The argument SYNTAX is a bit mask comprised of the various bits
+   defined in regex.h.  We return the old syntax.  */
+
+#ifdef __STDC__
+reg_syntax_t
+re_set_syntax (reg_syntax_t syntax)
+#else
+reg_syntax_t
+re_set_syntax (syntax)
+    reg_syntax_t syntax;
+#endif
+{
+  reg_syntax_t ret = re_syntax_options;
+
+  re_syntax_options = syntax;
+  return ret;
+}
+
+
+/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
+   ENDS.  Subsequent matches using PATTERN_BUFFER and REGS will use
+   this memory for recording register information.  STARTS and ENDS
+   must be allocated using the malloc library routine, and must each
+   be at least NUM_REGS * sizeof (regoff_t) bytes long.
+
+   If NUM_REGS == 0, then subsequent matches should allocate their own
+   register data.
+
+   Unless this function is called, the first search or match using
+   PATTERN_BUFFER will allocate its own register data, without
+   freeing the old data.  */
+
+#ifdef __STDC__
+void
+re_set_registers (struct re_pattern_buffer *bufp,
+		  struct re_registers *regs,
+		  unsigned num_regs,
+		  regoff_t * starts, regoff_t * ends)
+#else
+void
+re_set_registers (bufp, regs, num_regs, starts, ends)
+     struct re_pattern_buffer *bufp;
+     struct re_registers *regs;
+     unsigned num_regs;
+     regoff_t * starts;
+     regoff_t * ends;
+#endif
+{
+  if (num_regs)
+    {
+      bufp->regs_allocated = REGS_REALLOCATE;
+      regs->num_regs = num_regs;
+      regs->start = starts;
+      regs->end = ends;
+    }
+  else
+    {
+      bufp->regs_allocated = REGS_UNALLOCATED;
+      regs->num_regs = 0;
+      regs->start = regs->end = (regoff_t) 0;
+    }
+}
+
+
+
+
+#ifdef __STDC__
+static int 
+cplx_se_sublist_len (struct rx_se_list * list)
+#else
+static int 
+cplx_se_sublist_len (list)
+     struct rx_se_list * list;
+#endif
+{
+  int x = 0;
+  while (list)
+    {
+      if ((long)list->car >= 0)
+	++x;
+      list = list->cdr;
+    }
+  return x;
+}
+
+
+/* For rx->se_list_cmp */
+
+#ifdef __STDC__
+static int 
+posix_se_list_order (struct rx * rx,
+		     struct rx_se_list * a, struct rx_se_list * b)
+#else
+static int 
+posix_se_list_order (rx, a, b)
+     struct rx * rx;
+     struct rx_se_list * a;
+     struct rx_se_list * b;
+#endif
+{
+  int al = cplx_se_sublist_len (a);
+  int bl = cplx_se_sublist_len (b);
+
+  if (!al && !bl)
+    return ((a == b)
+	    ? 0
+	    : ((a < b) ? -1 : 1));
+  
+  else if (!al)
+    return -1;
+
+  else if (!bl)
+    return 1;
+
+  else
+    {
+      rx_side_effect * av = ((rx_side_effect *)
+			     alloca (sizeof (rx_side_effect) * (al + 1)));
+      rx_side_effect * bv = ((rx_side_effect *)
+			     alloca (sizeof (rx_side_effect) * (bl + 1)));
+      struct rx_se_list * ap = a;
+      struct rx_se_list * bp = b;
+      int ai, bi;
+      
+      for (ai = al - 1; ai >= 0; --ai)
+	{
+	  while ((long)ap->car < 0)
+	    ap = ap->cdr;
+	  av[ai] = ap->car;
+	  ap = ap->cdr;
+	}
+      av[al] = (rx_side_effect)-2;
+      for (bi = bl - 1; bi >= 0; --bi)
+	{
+	  while ((long)bp->car < 0)
+	    bp = bp->cdr;
+	  bv[bi] = bp->car;
+	  bp = bp->cdr;
+	}
+      bv[bl] = (rx_side_effect)-1;
+
+      {
+	int ret;
+	int x = 0;
+	while (av[x] == bv[x])
+	  ++x;
+ 	ret = (((unsigned *)(av[x]) < (unsigned *)(bv[x])) ? -1 : 1);
+	return ret;
+      }
+    }
+}
+
+
+
+
+/* re_compile_pattern is the GNU regular expression compiler: it
+   compiles PATTERN (of length SIZE) and puts the result in RXB.
+   Returns 0 if the pattern was valid, otherwise an error string.
+
+   Assumes the `allocated' (and perhaps `buffer') and `translate' fields
+   are set in RXB on entry.
+
+   We call rx_compile to do the actual compilation.  */
+
+#ifdef __STDC__
+__const__ char *
+re_compile_pattern (__const__ char *pattern,
+		    int length,
+		    struct re_pattern_buffer * rxb)
+#else
+__const__ char *
+re_compile_pattern (pattern, length, rxb)
+     __const__ char *pattern;
+     int length;
+     struct re_pattern_buffer * rxb;
+#endif
+{
+  reg_errcode_t ret;
+
+  /* GNU code is written to assume at least RE_NREGS registers will be set
+     (and at least one extra will be -1).  */
+  rxb->regs_allocated = REGS_UNALLOCATED;
+
+  /* And GNU code determines whether or not to get register information
+     by passing null for the REGS argument to re_match, etc., not by
+     setting no_sub.  */
+  rxb->no_sub = 0;
+
+  rxb->rx.local_cset_size = 256;
+
+  /* Match anchors at newline.  */
+  rxb->newline_anchor = 1;
+ 
+  rxb->re_nsub = 0;
+  rxb->start = 0;
+  rxb->se_params = 0;
+  rxb->rx.nodec = 0;
+  rxb->rx.epsnodec = 0;
+  rxb->rx.instruction_table = 0;
+  rxb->rx.nfa_states = 0;
+  rxb->rx.se_list_cmp = posix_se_list_order;
+  rxb->rx.start_set = 0;
+
+  ret = rx_compile (pattern, length, re_syntax_options, rxb);
+  alloca (0);
+  return rx_error_msg[(int) ret];
+}
+
+
+
+#ifdef __STDC__
+int
+re_compile_fastmap (struct re_pattern_buffer * rxb)
+#else
+int
+re_compile_fastmap (rxb)
+     struct re_pattern_buffer * rxb;
+#endif
+{
+  rx_blow_up_fastmap (rxb);
+  return 0;
+}
+
+
+
+
+/* Entry points compatible with 4.2 BSD regex library.  We don't define
+   them if this is an Emacs or POSIX compilation.  */
+
+#if (!defined (emacs) && !defined (_POSIX_SOURCE)) || defined(USE_BSD_REGEX)
+
+/* BSD has one and only one pattern buffer.  */
+static struct re_pattern_buffer rx_comp_buf;
+
+#ifdef __STDC__
+char *
+re_comp (__const__ char *s)
+#else
+char *
+re_comp (s)
+    __const__ char *s;
+#endif
+{
+  reg_errcode_t ret;
+
+  if (!s || (*s == '\0'))
+    {
+      if (!rx_comp_buf.buffer)
+	return "No previous regular expression";
+      return 0;
+    }
+
+  if (!rx_comp_buf.fastmap)
+    {
+      rx_comp_buf.fastmap = (char *) malloc (1 << CHARBITS);
+      if (!rx_comp_buf.fastmap)
+	return "Memory exhausted";
+    }
+
+  /* Since `rx_exec' always passes NULL for the `regs' argument, we
+     don't need to initialize the pattern buffer fields which affect it.  */
+
+  /* Match anchors at newlines.  */
+  rx_comp_buf.newline_anchor = 1;
+
+  rx_comp_buf.re_nsub = 0;
+  rx_comp_buf.start = 0;
+  rx_comp_buf.se_params = 0;
+  rx_comp_buf.rx.nodec = 0;
+  rx_comp_buf.rx.epsnodec = 0;
+  rx_comp_buf.rx.instruction_table = 0;
+  rx_comp_buf.rx.nfa_states = 0;
+  rx_comp_buf.rx.start = 0;
+  rx_comp_buf.rx.se_list_cmp = posix_se_list_order;
+  rx_comp_buf.rx.local_cset_size = 256;
+
+  ret = rx_compile (s, strlen (s), re_syntax_options, &rx_comp_buf);
+  alloca (0);
+
+  /* Yes, we're discarding `__const__' here.  */
+  return (char *) rx_error_msg[(int) ret];
+}
+
+
+#ifdef __STDC__
+int
+re_exec (__const__ char *s)
+#else
+int
+re_exec (s)
+    __const__ char *s;
+#endif
+{
+  __const__ int len = strlen (s);
+  return
+    0 <= re_search (&rx_comp_buf, s, len, 0, len, (struct re_registers *) 0);
+}
+#endif /* not emacs and not _POSIX_SOURCE */
+
+
+
+/* POSIX.2 functions.  Don't define these for Emacs.  */
+
+#if !defined(emacs)
+
+/* regcomp takes a regular expression as a string and compiles it.
+
+   PREG is a regex_t *.  We do not expect any fields to be initialized,
+   since POSIX says we shouldn't.  Thus, we set
+
+     `buffer' to the compiled pattern;
+     `used' to the length of the compiled pattern;
+     `syntax' to RE_SYNTAX_POSIX_EXTENDED if the
+       REG_EXTENDED bit in CFLAGS is set; otherwise, to
+       RE_SYNTAX_POSIX_BASIC;
+     `newline_anchor' to REG_NEWLINE being set in CFLAGS;
+     `fastmap' and `fastmap_accurate' to zero;
+     `re_nsub' to the number of subexpressions in PATTERN.
+
+   PATTERN is the address of the pattern string.
+
+   CFLAGS is a series of bits which affect compilation.
+
+     If REG_EXTENDED is set, we use POSIX extended syntax; otherwise, we
+     use POSIX basic syntax.
+
+     If REG_NEWLINE is set, then . and [^...] don't match newline.
+     Also, regexec will try a match beginning after every newline.
+
+     If REG_ICASE is set, then we considers upper- and lowercase
+     versions of letters to be equivalent when matching.
+
+     If REG_NOSUB is set, then when PREG is passed to regexec, that
+     routine will report only success or failure, and nothing about the
+     registers.
+
+   It returns 0 if it succeeds, nonzero if it doesn't.  (See regex.h for
+   the return codes and their meanings.)  */
+
+
+#ifdef __STDC__
+int
+regcomp (regex_t * preg, __const__ char * pattern, int cflags)
+#else
+int
+regcomp (preg, pattern, cflags)
+    regex_t * preg;
+    __const__ char * pattern;
+    int cflags;
+#endif
+{
+  reg_errcode_t ret;
+  unsigned syntax
+    = cflags & REG_EXTENDED ? RE_SYNTAX_POSIX_EXTENDED : RE_SYNTAX_POSIX_BASIC;
+
+  /* regex_compile will allocate the space for the compiled pattern.  */
+  preg->buffer = 0;
+  preg->allocated = 0;
+  preg->fastmap = malloc (256);
+  if (!preg->fastmap)
+    return REG_ESPACE;
+  preg->fastmap_accurate = 0;
+
+  if (cflags & REG_ICASE)
+    {
+      unsigned i;
+
+      preg->translate = (unsigned char *) malloc (256);
+      if (!preg->translate)
+        return (int) REG_ESPACE;
+
+      /* Map uppercase characters to corresponding lowercase ones.  */
+      for (i = 0; i < CHAR_SET_SIZE; i++)
+        preg->translate[i] = isupper (i) ? tolower (i) : i;
+    }
+  else
+    preg->translate = 0;
+
+  /* If REG_NEWLINE is set, newlines are treated differently.  */
+  if (cflags & REG_NEWLINE)
+    { /* REG_NEWLINE implies neither . nor [^...] match newline.  */
+      syntax &= ~RE_DOT_NEWLINE;
+      syntax |= RE_HAT_LISTS_NOT_NEWLINE;
+      /* It also changes the matching behavior.  */
+      preg->newline_anchor = 1;
+    }
+  else
+    preg->newline_anchor = 0;
+
+  preg->no_sub = !!(cflags & REG_NOSUB);
+
+  /* POSIX says a null character in the pattern terminates it, so we
+     can use strlen here in compiling the pattern.  */
+  preg->re_nsub = 0;
+  preg->start = 0;
+  preg->se_params = 0;
+  preg->syntax_parens = 0;
+  preg->rx.nodec = 0;
+  preg->rx.epsnodec = 0;
+  preg->rx.instruction_table = 0;
+  preg->rx.nfa_states = 0;
+  preg->rx.local_cset_size = 256;
+  preg->rx.start = 0;
+  preg->rx.se_list_cmp = posix_se_list_order;
+  preg->rx.start_set = 0;
+  ret = rx_compile (pattern, strlen (pattern), syntax, preg);
+  alloca (0);
+
+  /* POSIX doesn't distinguish between an unmatched open-group and an
+     unmatched close-group: both are REG_EPAREN.  */
+  if (ret == REG_ERPAREN) ret = REG_EPAREN;
+
+  return (int) ret;
+}
+
+
+/* regexec searches for a given pattern, specified by PREG, in the
+   string STRING.
+
+   If NMATCH is zero or REG_NOSUB was set in the cflags argument to
+   `regcomp', we ignore PMATCH.  Otherwise, we assume PMATCH has at
+   least NMATCH elements, and we set them to the offsets of the
+   corresponding matched substrings.
+
+   EFLAGS specifies `execution flags' which affect matching: if
+   REG_NOTBOL is set, then ^ does not match at the beginning of the
+   string; if REG_NOTEOL is set, then $ does not match at the end.
+
+   We return 0 if we find a match and REG_NOMATCH if not.  */
+
+#ifdef __STDC__
+int
+regexec (__const__ regex_t *preg, __const__ char *string,
+	 size_t nmatch, regmatch_t pmatch[],
+	 int eflags)
+#else
+int
+regexec (preg, string, nmatch, pmatch, eflags)
+    __const__ regex_t *preg;
+    __const__ char *string;
+    size_t nmatch;
+    regmatch_t pmatch[];
+    int eflags;
+#endif
+{
+  int ret;
+  struct re_registers regs;
+  regex_t private_preg;
+  int len = strlen (string);
+  boolean want_reg_info = !preg->no_sub && nmatch > 0;
+
+  private_preg = *preg;
+
+  private_preg.not_bol = !!(eflags & REG_NOTBOL);
+  private_preg.not_eol = !!(eflags & REG_NOTEOL);
+
+  /* The user has told us exactly how many registers to return
+   * information about, via `nmatch'.  We have to pass that on to the
+   * matching routines.
+   */
+  private_preg.regs_allocated = REGS_FIXED;
+
+  if (want_reg_info)
+    {
+      regs.num_regs = nmatch;
+      regs.start =  (( regoff_t *) malloc ((nmatch) * sizeof ( regoff_t)));
+      regs.end =  (( regoff_t *) malloc ((nmatch) * sizeof ( regoff_t)));
+      if (regs.start == 0 || regs.end == 0)
+        return (int) REG_NOMATCH;
+    }
+
+  /* Perform the searching operation.  */
+  ret = re_search (&private_preg,
+		   string, len,
+                   /* start: */ 0,
+		   /* range: */ len,
+                   want_reg_info ? &regs : (struct re_registers *) 0);
+
+  /* Copy the register information to the POSIX structure.  */
+  if (want_reg_info)
+    {
+      if (ret >= 0)
+        {
+          unsigned r;
+
+          for (r = 0; r < nmatch; r++)
+            {
+              pmatch[r].rm_so = regs.start[r];
+              pmatch[r].rm_eo = regs.end[r];
+            }
+        }
+
+      /* If we needed the temporary register info, free the space now.  */
+      free (regs.start);
+      free (regs.end);
+    }
+
+  /* We want zero return to mean success, unlike `re_search'.  */
+  return ret >= 0 ? (int) REG_NOERROR : (int) REG_NOMATCH;
+}
+
+
+/* Returns a message corresponding to an error code, ERRCODE, returned
+   from either regcomp or regexec.   */
+
+#ifdef __STDC__
+size_t
+regerror (int errcode, __const__ regex_t *preg,
+	  char *errbuf, size_t errbuf_size)
+#else
+size_t
+regerror (errcode, preg, errbuf, errbuf_size)
+    int errcode;
+    __const__ regex_t *preg;
+    char *errbuf;
+    size_t errbuf_size;
+#endif
+{
+  __const__ char *msg
+    = rx_error_msg[errcode] == 0 ? "Success" : rx_error_msg[errcode];
+  size_t msg_size = strlen (msg) + 1; /* Includes the 0.  */
+
+  if (errbuf_size != 0)
+    {
+      if (msg_size > errbuf_size)
+        {
+          strncpy (errbuf, msg, errbuf_size - 1);
+          errbuf[errbuf_size - 1] = 0;
+        }
+      else
+        strcpy (errbuf, msg);
+    }
+
+  return msg_size;
+}
+
+
+/* Free dynamically allocated space used by PREG.  */
+
+#ifdef __STDC__
+void
+regfree (regex_t *preg)
+#else
+void
+regfree (preg)
+    regex_t *preg;
+#endif
+{
+  if (preg->buffer != 0)
+    free (preg->buffer);
+  preg->buffer = 0;
+  preg->allocated = 0;
+
+  if (preg->fastmap != 0)
+    free (preg->fastmap);
+  preg->fastmap = 0;
+  preg->fastmap_accurate = 0;
+
+  if (preg->translate != 0)
+    free (preg->translate);
+  preg->translate = 0;
+}
+
+#endif /* not emacs  */
+
+
+
+
+