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rx.c

/*    Copyright (C) 1992, 1993, 1994, 1995, 1996 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


char rx_version_string[] = "GNU Rx version 0.07.2";

                  /* ``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 */

#ifndef RX_WANT_RX_DEFS
RX_DECL char re_syntax_table[CHAR_SET_SIZE];
#endif

#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;
              if (df)
                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,
                              rx_copy_rexp (&rxb->rx,
                                        inner_exp),
                              *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)
    {
      if ((pos->string == closure->string1)
        && (closure->string2)
        && (closure->size2 > 1))
        return closure->string2[1];
      else
        return 0;
    }
  else if (pos->pos+1 == pos->end)
    {
      if ((pos->string == closure->string1)
        && (closure->string2)
        && (closure->size2))
        return closure->string2[0];
      else
        return 0;
    }
  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.  */

/* Don't build them for libg++ either.  This is a temporary measure
 * until the functions are moved to another file and reconditionalized.
 */
#if 0
/* #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.fastmap_accurate = 0;
  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.start_set = 0;
  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.  */

/* For now we leave these out, because regex_t is not binary
   compatible with the implementation in other systems. */
/* Except for CYGWIN32 which has no implementation other than this. */
#if defined(__CYGWIN32__) /* !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  */

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