win32: Import regex source

These were extracted from commit
e56b799d6ad8afba4168fffa7218d44c041a72d2
in Git repository. Changes from the original version:

> diff --git a/tmp/regex.c b/win32/regex.c
> index 87b33e4..2cca169 100644
> --- a/tmp/regex.c
> +++ b/win32/regex.c
> @@ -24,7 +24,9 @@
>    #pragma alloca
>  #endif
>
> +#ifndef _GNU_SOURCE
>  #define _GNU_SOURCE
> +#endif
>
>  /* We need this for `regex.h', and perhaps for the Emacs include files.  */
>  #include <sys/types.h>

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>

2 files changed, 5419 insertions, 0 deletions

diff --git a/win32/regex.c b/win32/regex.c
new file mode 100644
index 000000000..2cca16934
--- /dev/null
+++ b/win32/regex.c
@@ -0,0 +1,4929 @@
+/* Extended regular expression matching and search library,
+   version 0.12.
+   (Implements POSIX draft P10003.2/D11.2, except for
+   internationalization features.)
+
+   Copyright (C) 1993 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program 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 General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* AIX requires this to be the first thing in the file. */
+#if defined (_AIX) && !defined (REGEX_MALLOC)
+  #pragma alloca
+#endif
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+/* We need this for `regex.h', and perhaps for the Emacs include files.  */
+#include <sys/types.h>
+
+/* We used to test for `BSTRING' here, but only GCC and Emacs define
+   `BSTRING', as far as I know, and neither of them use this code.  */
+#include <string.h>
+#ifndef bcmp
+#define bcmp(s1, s2, n) memcmp ((s1), (s2), (n))
+#endif
+#ifndef bcopy
+#define bcopy(s, d, n)  memcpy ((d), (s), (n))
+#endif
+#ifndef bzero
+#define bzero(s, n)     memset ((s), 0, (n))
+#endif
+
+#include <stdlib.h>
+
+
+/* Define the syntax stuff for \<, \>, etc.  */
+
+/* This must be nonzero for the wordchar and notwordchar pattern
+   commands in re_match_2.  */
+#ifndef Sword
+#define Sword 1
+#endif
+
+#ifdef SYNTAX_TABLE
+
+extern char *re_syntax_table;
+
+#else /* not SYNTAX_TABLE */
+
+/* How many characters in the character set.  */
+#define CHAR_SET_SIZE 256
+
+static char re_syntax_table[CHAR_SET_SIZE];
+
+static void
+init_syntax_once ()
+{
+   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 */
+
+#define SYNTAX(c) re_syntax_table[c]
+
+
+/* Get the interface, including the syntax bits.  */
+#include "regex.h"
+
+/* isalpha etc. are used for the character classes.  */
+#include <ctype.h>
+
+#ifndef isascii
+#define isascii(c) 1
+#endif
+
+#ifdef isblank
+#define ISBLANK(c) (isascii (c) && isblank (c))
+#else
+#define ISBLANK(c) ((c) == ' ' || (c) == '\t')
+#endif
+#ifdef isgraph
+#define ISGRAPH(c) (isascii (c) && isgraph (c))
+#else
+#define ISGRAPH(c) (isascii (c) && isprint (c) && !isspace (c))
+#endif
+
+#define ISPRINT(c) (isascii (c) && isprint (c))
+#define ISDIGIT(c) (isascii (c) && isdigit (c))
+#define ISALNUM(c) (isascii (c) && isalnum (c))
+#define ISALPHA(c) (isascii (c) && isalpha (c))
+#define ISCNTRL(c) (isascii (c) && iscntrl (c))
+#define ISLOWER(c) (isascii (c) && islower (c))
+#define ISPUNCT(c) (isascii (c) && ispunct (c))
+#define ISSPACE(c) (isascii (c) && isspace (c))
+#define ISUPPER(c) (isascii (c) && isupper (c))
+#define ISXDIGIT(c) (isascii (c) && isxdigit (c))
+
+#ifndef NULL
+#define NULL 0
+#endif
+
+/* We remove any previous definition of `SIGN_EXTEND_CHAR',
+   since ours (we hope) works properly with all combinations of
+   machines, compilers, `char' and `unsigned char' argument types.
+   (Per Bothner suggested the basic approach.)  */
+#undef SIGN_EXTEND_CHAR
+#if __STDC__
+#define SIGN_EXTEND_CHAR(c) ((signed char) (c))
+#else  /* not __STDC__ */
+/* As in Harbison and Steele.  */
+#define SIGN_EXTEND_CHAR(c) ((((unsigned char) (c)) ^ 128) - 128)
+#endif
+
+/* Should we use malloc or alloca?  If REGEX_MALLOC is not defined, we
+   use `alloca' instead of `malloc'.  This is because using malloc in
+   re_search* or re_match* could cause memory leaks when C-g is used in
+   Emacs; also, malloc is slower and causes storage fragmentation.  On
+   the other hand, malloc is more portable, and easier to debug.
+
+   Because we sometimes use alloca, some routines have to be macros,
+   not functions -- `alloca'-allocated space disappears at the end of the
+   function it is called in.  */
+
+#ifdef REGEX_MALLOC
+
+#define REGEX_ALLOCATE malloc
+#define REGEX_REALLOCATE(source, osize, nsize) realloc (source, nsize)
+
+#else /* not REGEX_MALLOC  */
+
+/* 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 */
+
+#define REGEX_ALLOCATE alloca
+
+/* Assumes a `char *destination' variable.  */
+#define REGEX_REALLOCATE(source, osize, nsize)                          \
+  (destination = (char *) alloca (nsize),                               \
+   bcopy (source, destination, osize),                                  \
+   destination)
+
+#endif /* not REGEX_MALLOC */
+
+
+/* True if `size1' is non-NULL and PTR is pointing anywhere inside
+   `string1' or just past its end.  This works if PTR is NULL, which is
+   a good thing.  */
+#define FIRST_STRING_P(ptr)                                     \
+  (size1 && string1 <= (ptr) && (ptr) <= string1 + size1)
+
+/* (Re)Allocate N items of type T using malloc, or fail.  */
+#define TALLOC(n, t) ((t *) malloc ((n) * sizeof (t)))
+#define RETALLOC(addr, n, t) ((addr) = (t *) realloc (addr, (n) * sizeof (t)))
+#define REGEX_TALLOC(n, t) ((t *) REGEX_ALLOCATE ((n) * sizeof (t)))
+
+#define BYTEWIDTH 8 /* In bits.  */
+
+#define STREQ(s1, s2) ((strcmp (s1, s2) == 0))
+
+#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
+
+/* These are the command codes that appear in compiled regular
+   expressions.  Some opcodes are followed by argument bytes.  A
+   command code can specify any interpretation whatsoever for its
+   arguments.  Zero bytes may appear in the compiled regular expression.
+
+   The value of `exactn' is needed in search.c (search_buffer) in Emacs.
+   So regex.h defines a symbol `RE_EXACTN_VALUE' to be 1; the value of
+   `exactn' we use here must also be 1.  */
+
+typedef enum
+{
+  no_op = 0,
+
+        /* Followed by one byte giving n, then by n literal bytes.  */
+  exactn = 1,
+
+        /* Matches any (more or less) character.  */
+  anychar,
+
+        /* Matches any one char belonging to specified set.  First
+           following byte is number of bitmap bytes.  Then come bytes
+           for a bitmap saying which chars are in.  Bits in each byte
+           are ordered low-bit-first.  A character is in the set if its
+           bit is 1.  A character too large to have a bit in the map is
+           automatically not in the set.  */
+  charset,
+
+        /* Same parameters as charset, but match any character that is
+           not one of those specified.  */
+  charset_not,
+
+        /* Start remembering the text that is matched, for storing in a
+           register.  Followed by one byte with the register number, in
+           the range 0 to one less than the pattern buffer's re_nsub
+           field.  Then followed by one byte with the number of groups
+           inner to this one.  (This last has to be part of the
+           start_memory only because we need it in the on_failure_jump
+           of re_match_2.)  */
+  start_memory,
+
+        /* Stop remembering the text that is matched and store it in a
+           memory register.  Followed by one byte with the register
+           number, in the range 0 to one less than `re_nsub' in the
+           pattern buffer, and one byte with the number of inner groups,
+           just like `start_memory'.  (We need the number of inner
+           groups here because we don't have any easy way of finding the
+           corresponding start_memory when we're at a stop_memory.)  */
+  stop_memory,
+
+        /* Match a duplicate of something remembered. Followed by one
+           byte containing the register number.  */
+  duplicate,
+
+        /* Fail unless at beginning of line.  */
+  begline,
+
+        /* Fail unless at end of line.  */
+  endline,
+
+        /* Succeeds if at beginning of buffer (if emacs) or at beginning
+           of string to be matched (if not).  */
+  begbuf,
+
+        /* Analogously, for end of buffer/string.  */
+  endbuf,
+
+        /* Followed by two byte relative address to which to jump.  */
+  jump,
+
+        /* Same as jump, but marks the end of an alternative.  */
+  jump_past_alt,
+
+        /* Followed by two-byte relative address of place to resume at
+           in case of failure.  */
+  on_failure_jump,
+
+        /* Like on_failure_jump, but pushes a placeholder instead of the
+           current string position when executed.  */
+  on_failure_keep_string_jump,
+
+        /* Throw away latest failure point and then jump to following
+           two-byte relative address.  */
+  pop_failure_jump,
+
+        /* Change to pop_failure_jump if know won't have to backtrack to
+           match; otherwise change to jump.  This is used to jump
+           back to the beginning of a repeat.  If what follows this jump
+           clearly won't match what the repeat does, such that we can be
+           sure that there is no use backtracking out of repetitions
+           already matched, then we change it to a pop_failure_jump.
+           Followed by two-byte address.  */
+  maybe_pop_jump,
+
+        /* Jump to following two-byte address, and push a dummy failure
+           point. This failure point will be thrown away if an attempt
+           is made to use it for a failure.  A `+' construct makes this
+           before the first repeat.  Also used as an intermediary kind
+           of jump when compiling an alternative.  */
+  dummy_failure_jump,
+
+        /* Push a dummy failure point and continue.  Used at the end of
+           alternatives.  */
+  push_dummy_failure,
+
+        /* Followed by two-byte relative address and two-byte number n.
+           After matching N times, jump to the address upon failure.  */
+  succeed_n,
+
+        /* Followed by two-byte relative address, and two-byte number n.
+           Jump to the address N times, then fail.  */
+  jump_n,
+
+        /* Set the following two-byte relative address to the
+           subsequent two-byte number.  The address *includes* the two
+           bytes of number.  */
+  set_number_at,
+
+  wordchar,     /* Matches any word-constituent character.  */
+  notwordchar,  /* Matches any char that is not a word-constituent.  */
+
+  wordbeg,      /* Succeeds if at word beginning.  */
+  wordend,      /* Succeeds if at word end.  */
+
+  wordbound,    /* Succeeds if at a word boundary.  */
+  notwordbound  /* Succeeds if not at a word boundary.  */
+
+#ifdef emacs
+  ,before_dot,  /* Succeeds if before point.  */
+  at_dot,       /* Succeeds if at point.  */
+  after_dot,    /* Succeeds if after point.  */
+
+        /* Matches any character whose syntax is specified.  Followed by
+           a byte which contains a syntax code, e.g., Sword.  */
+  syntaxspec,
+
+        /* Matches any character whose syntax is not that specified.  */
+  notsyntaxspec
+#endif /* emacs */
+} re_opcode_t;
+
+/* Common operations on the compiled pattern.  */
+
+/* Store NUMBER in two contiguous bytes starting at DESTINATION.  */
+
+#define STORE_NUMBER(destination, number)                               \
+  do {                                                                  \
+    (destination)[0] = (number) & 0377;                                 \
+    (destination)[1] = (number) >> 8;                                   \
+  } while (0)
+
+/* Same as STORE_NUMBER, except increment DESTINATION to
+   the byte after where the number is stored.  Therefore, DESTINATION
+   must be an lvalue.  */
+
+#define STORE_NUMBER_AND_INCR(destination, number)                      \
+  do {                                                                  \
+    STORE_NUMBER (destination, number);                                 \
+    (destination) += 2;                                                 \
+  } while (0)
+
+/* Put into DESTINATION a number stored in two contiguous bytes starting
+   at SOURCE.  */
+
+#define EXTRACT_NUMBER(destination, source)                             \
+  do {                                                                  \
+    (destination) = *(source) & 0377;                                   \
+    (destination) += SIGN_EXTEND_CHAR (*((source) + 1)) << 8;           \
+  } while (0)
+
+#ifdef DEBUG
+static void
+extract_number (dest, source)
+    int *dest;
+    unsigned char *source;
+{
+  int temp = SIGN_EXTEND_CHAR (*(source + 1));
+  *dest = *source & 0377;
+  *dest += temp << 8;
+}
+
+#ifndef EXTRACT_MACROS /* To debug the macros.  */
+#undef EXTRACT_NUMBER
+#define EXTRACT_NUMBER(dest, src) extract_number (&dest, src)
+#endif /* not EXTRACT_MACROS */
+
+#endif /* DEBUG */
+
+/* Same as EXTRACT_NUMBER, except increment SOURCE to after the number.
+   SOURCE must be an lvalue.  */
+
+#define EXTRACT_NUMBER_AND_INCR(destination, source)                    \
+  do {                                                                  \
+    EXTRACT_NUMBER (destination, source);                               \
+    (source) += 2;                                                      \
+  } while (0)
+
+#ifdef DEBUG
+static void
+extract_number_and_incr (destination, source)
+    int *destination;
+    unsigned char **source;
+{
+  extract_number (destination, *source);
+  *source += 2;
+}
+
+#ifndef EXTRACT_MACROS
+#undef EXTRACT_NUMBER_AND_INCR
+#define EXTRACT_NUMBER_AND_INCR(dest, src) \
+  extract_number_and_incr (&dest, &src)
+#endif /* not EXTRACT_MACROS */
+
+#endif /* DEBUG */
+
+/* If DEBUG is defined, Regex prints many voluminous messages about what
+   it is doing (if the variable `debug' is nonzero).  If linked with the
+   main program in `iregex.c', you can enter patterns and strings
+   interactively.  And if linked with the main program in `main.c' and
+   the other test files, you can run the already-written tests.  */
+
+#ifdef DEBUG
+
+/* We use standard I/O for debugging.  */
+#include <stdio.h>
+
+/* It is useful to test things that ``must'' be true when debugging.  */
+#include <assert.h>
+
+static int debug = 0;
+
+#define DEBUG_STATEMENT(e) e
+#define DEBUG_PRINT1(x) if (debug) printf (x)
+#define DEBUG_PRINT2(x1, x2) if (debug) printf (x1, x2)
+#define DEBUG_PRINT3(x1, x2, x3) if (debug) printf (x1, x2, x3)
+#define DEBUG_PRINT4(x1, x2, x3, x4) if (debug) printf (x1, x2, x3, x4)
+#define DEBUG_PRINT_COMPILED_PATTERN(p, s, e)                           \
+  if (debug) print_partial_compiled_pattern (s, e)
+#define DEBUG_PRINT_DOUBLE_STRING(w, s1, sz1, s2, sz2)                  \
+  if (debug) print_double_string (w, s1, sz1, s2, sz2)
+
+
+extern void printchar ();
+
+/* Print the fastmap in human-readable form.  */
+
+void
+print_fastmap (fastmap)
+    char *fastmap;
+{
+  unsigned was_a_range = 0;
+  unsigned i = 0;
+
+  while (i < (1 << BYTEWIDTH))
+    {
+      if (fastmap[i++])
+        {
+          was_a_range = 0;
+          printchar (i - 1);
+          while (i < (1 << BYTEWIDTH)  &&  fastmap[i])
+            {
+              was_a_range = 1;
+              i++;
+            }
+          if (was_a_range)
+            {
+              printf ("-");
+              printchar (i - 1);
+            }
+        }
+    }
+  putchar ('\n');
+}
+
+
+/* Print a compiled pattern string in human-readable form, starting at
+   the START pointer into it and ending just before the pointer END.  */
+
+void
+print_partial_compiled_pattern (start, end)
+    unsigned char *start;
+    unsigned char *end;
+{
+  int mcnt, mcnt2;
+  unsigned char *p = start;
+  unsigned char *pend = end;
+
+  if (start == NULL)
+    {
+      printf ("(null)\n");
+      return;
+    }
+
+  /* Loop over pattern commands.  */
+  while (p < pend)
+    {
+      switch ((re_opcode_t) *p++)
+        {
+        case no_op:
+          printf ("/no_op");
+          break;
+
+        case exactn:
+          mcnt = *p++;
+          printf ("/exactn/%d", mcnt);
+          do
+            {
+              putchar ('/');
+              printchar (*p++);
+            }
+          while (--mcnt);
+          break;
+
+        case start_memory:
+          mcnt = *p++;
+          printf ("/start_memory/%d/%d", mcnt, *p++);
+          break;
+
+        case stop_memory:
+          mcnt = *p++;
+          printf ("/stop_memory/%d/%d", mcnt, *p++);
+          break;
+
+        case duplicate:
+          printf ("/duplicate/%d", *p++);
+          break;
+
+        case anychar:
+          printf ("/anychar");
+          break;
+
+        case charset:
+        case charset_not:
+          {
+            register int c;
+
+            printf ("/charset%s",
+                    (re_opcode_t) *(p - 1) == charset_not ? "_not" : "");
+
+            assert (p + *p < pend);
+
+            for (c = 0; c < *p; c++)
+              {
+                unsigned bit;
+                unsigned char map_byte = p[1 + c];
+
+                putchar ('/');
+
+                for (bit = 0; bit < BYTEWIDTH; bit++)
+                  if (map_byte & (1 << bit))
+                    printchar (c * BYTEWIDTH + bit);
+              }
+            p += 1 + *p;
+            break;
+          }
+
+        case begline:
+          printf ("/begline");
+          break;
+
+        case endline:
+          printf ("/endline");
+          break;
+
+        case on_failure_jump:
+          extract_number_and_incr (&mcnt, &p);
+          printf ("/on_failure_jump/0/%d", mcnt);
+          break;
+
+        case on_failure_keep_string_jump:
+          extract_number_and_incr (&mcnt, &p);
+          printf ("/on_failure_keep_string_jump/0/%d", mcnt);
+          break;
+
+        case dummy_failure_jump:
+          extract_number_and_incr (&mcnt, &p);
+          printf ("/dummy_failure_jump/0/%d", mcnt);
+          break;
+
+        case push_dummy_failure:
+          printf ("/push_dummy_failure");
+          break;
+
+        case maybe_pop_jump:
+          extract_number_and_incr (&mcnt, &p);
+          printf ("/maybe_pop_jump/0/%d", mcnt);
+          break;
+
+        case pop_failure_jump:
+          extract_number_and_incr (&mcnt, &p);
+          printf ("/pop_failure_jump/0/%d", mcnt);
+          break;
+
+        case jump_past_alt:
+          extract_number_and_incr (&mcnt, &p);
+          printf ("/jump_past_alt/0/%d", mcnt);
+          break;
+
+        case jump:
+          extract_number_and_incr (&mcnt, &p);
+          printf ("/jump/0/%d", mcnt);
+          break;
+
+        case succeed_n:
+          extract_number_and_incr (&mcnt, &p);
+          extract_number_and_incr (&mcnt2, &p);
+          printf ("/succeed_n/0/%d/0/%d", mcnt, mcnt2);
+          break;
+
+        case jump_n:
+          extract_number_and_incr (&mcnt, &p);
+          extract_number_and_incr (&mcnt2, &p);
+          printf ("/jump_n/0/%d/0/%d", mcnt, mcnt2);
+          break;
+
+        case set_number_at:
+          extract_number_and_incr (&mcnt, &p);
+          extract_number_and_incr (&mcnt2, &p);
+          printf ("/set_number_at/0/%d/0/%d", mcnt, mcnt2);
+          break;
+
+        case wordbound:
+          printf ("/wordbound");
+          break;
+
+        case notwordbound:
+          printf ("/notwordbound");
+          break;
+
+        case wordbeg:
+          printf ("/wordbeg");
+          break;
+
+        case wordend:
+          printf ("/wordend");
+
+#ifdef emacs
+        case before_dot:
+          printf ("/before_dot");
+          break;
+
+        case at_dot:
+          printf ("/at_dot");
+          break;
+
+        case after_dot:
+          printf ("/after_dot");
+          break;
+
+        case syntaxspec:
+          printf ("/syntaxspec");
+          mcnt = *p++;
+          printf ("/%d", mcnt);
+          break;
+
+        case notsyntaxspec:
+          printf ("/notsyntaxspec");
+          mcnt = *p++;
+          printf ("/%d", mcnt);
+          break;
+#endif /* emacs */
+
+        case wordchar:
+          printf ("/wordchar");
+          break;
+
+        case notwordchar:
+          printf ("/notwordchar");
+          break;
+
+        case begbuf:
+          printf ("/begbuf");
+          break;
+
+        case endbuf:
+          printf ("/endbuf");
+          break;
+
+        default:
+          printf ("?%d", *(p-1));
+        }
+    }
+  printf ("/\n");
+}
+
+
+void
+print_compiled_pattern (bufp)
+    struct re_pattern_buffer *bufp;
+{
+  unsigned char *buffer = bufp->buffer;
+
+  print_partial_compiled_pattern (buffer, buffer + bufp->used);
+  printf ("%d bytes used/%d bytes allocated.\n", bufp->used, bufp->allocated);
+
+  if (bufp->fastmap_accurate && bufp->fastmap)
+    {
+      printf ("fastmap: ");
+      print_fastmap (bufp->fastmap);
+    }
+
+  printf ("re_nsub: %d\t", bufp->re_nsub);
+  printf ("regs_alloc: %d\t", bufp->regs_allocated);
+  printf ("can_be_null: %d\t", bufp->can_be_null);
+  printf ("newline_anchor: %d\n", bufp->newline_anchor);
+  printf ("no_sub: %d\t", bufp->no_sub);
+  printf ("not_bol: %d\t", bufp->not_bol);
+  printf ("not_eol: %d\t", bufp->not_eol);
+  printf ("syntax: %d\n", bufp->syntax);
+  /* Perhaps we should print the translate table?  */
+}
+
+
+void
+print_double_string (where, string1, size1, string2, size2)
+    const char *where;
+    const char *string1;
+    const char *string2;
+    int size1;
+    int size2;
+{
+  unsigned this_char;
+
+  if (where == NULL)
+    printf ("(null)");
+  else
+    {
+      if (FIRST_STRING_P (where))
+        {
+          for (this_char = where - string1; this_char < size1; this_char++)
+            printchar (string1[this_char]);
+
+          where = string2;
+        }
+
+      for (this_char = where - string2; this_char < size2; this_char++)
+        printchar (string2[this_char]);
+    }
+}
+
+#else /* not DEBUG */
+
+#undef assert
+#define assert(e)
+
+#define DEBUG_STATEMENT(e)
+#define DEBUG_PRINT1(x)
+#define DEBUG_PRINT2(x1, x2)
+#define DEBUG_PRINT3(x1, x2, x3)
+#define DEBUG_PRINT4(x1, x2, x3, x4)
+#define DEBUG_PRINT_COMPILED_PATTERN(p, s, e)
+#define DEBUG_PRINT_DOUBLE_STRING(w, s1, sz1, s2, sz2)
+
+#endif /* not DEBUG */
+
+/* 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.  */
+
+reg_syntax_t
+re_set_syntax (syntax)
+    reg_syntax_t syntax;
+{
+  reg_syntax_t ret = re_syntax_options;
+
+  re_syntax_options = syntax;
+  return ret;
+}
+
+/* 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.  */
+
+static const char *re_error_msg[] =
+  { NULL,                                       /* 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 */
+  };
+
+/* Subroutine declarations and macros for regex_compile.  */
+
+static void store_op1 (), store_op2 ();
+static void insert_op1 (), insert_op2 ();
+static boolean at_begline_loc_p (), at_endline_loc_p ();
+static boolean group_in_compile_stack ();
+static reg_errcode_t compile_range ();
+
+/* 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++;                                           \
+    if (translate) 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--
+
+
+/* If `translate' is non-null, return translate[D], else just D.  We
+   cast the subscript to translate because some data is declared as
+   `char *', to avoid warnings when a string constant is passed.  But
+   when we use a character as a subscript we must make it unsigned.  */
+#define TRANSLATE(d) (translate ? translate[(unsigned char) (d)] : (d))
+
+
+/* Macros for outputting the compiled pattern into `buffer'.  */
+
+/* If the buffer isn't allocated when it comes in, use this.  */
+#define INIT_BUF_SIZE  32
+
+/* Make sure we have at least N more bytes of space in buffer.  */
+#define GET_BUFFER_SPACE(n)                                             \
+    while (b - bufp->buffer + (n) > bufp->allocated)                    \
+      EXTEND_BUFFER ()
+
+/* Make sure we have one more byte of buffer space and then add C to it.  */
+#define BUF_PUSH(c)                                                     \
+  do {                                                                  \
+    GET_BUFFER_SPACE (1);                                               \
+    *b++ = (unsigned char) (c);                                         \
+  } while (0)
+
+
+/* Ensure we have two more bytes of buffer space and then append C1 and C2.  */
+#define BUF_PUSH_2(c1, c2)                                              \
+  do {                                                                  \
+    GET_BUFFER_SPACE (2);                                               \
+    *b++ = (unsigned char) (c1);                                        \
+    *b++ = (unsigned char) (c2);                                        \
+  } while (0)
+
+
+/* As with BUF_PUSH_2, except for three bytes.  */
+#define BUF_PUSH_3(c1, c2, c3)                                          \
+  do {                                                                  \
+    GET_BUFFER_SPACE (3);                                               \
+    *b++ = (unsigned char) (c1);                                        \
+    *b++ = (unsigned char) (c2);                                        \
+    *b++ = (unsigned char) (c3);                                        \
+  } while (0)
+
+
+/* Store a jump with opcode OP at LOC to location TO.  We store a
+   relative address offset by the three bytes the jump itself occupies.  */
+#define STORE_JUMP(op, loc, to) \
+  store_op1 (op, loc, (to) - (loc) - 3)
+
+/* Likewise, for a two-argument jump.  */
+#define STORE_JUMP2(op, loc, to, arg) \
+  store_op2 (op, loc, (to) - (loc) - 3, arg)
+
+/* Like `STORE_JUMP', but for inserting.  Assume `b' is the buffer end.  */
+#define INSERT_JUMP(op, loc, to) \
+  insert_op1 (op, loc, (to) - (loc) - 3, b)
+
+/* Like `STORE_JUMP2', but for inserting.  Assume `b' is the buffer end.  */
+#define INSERT_JUMP2(op, loc, to, arg) \
+  insert_op2 (op, loc, (to) - (loc) - 3, arg, b)
+
+
+/* This is not an arbitrary limit: the arguments which represent offsets
+   into the pattern are two bytes long.  So if 2^16 bytes turns out to
+   be too small, many things would have to change.  */
+#define MAX_BUF_SIZE (1L << 16)
+
+
+/* Extend the buffer by twice its current size via realloc and
+   reset the pointers that pointed into the old block to point to the
+   correct places in the new one.  If extending the buffer results in it
+   being larger than MAX_BUF_SIZE, then flag memory exhausted.  */
+#define EXTEND_BUFFER()                                                 \
+  do {                                                                  \
+    unsigned char *old_buffer = bufp->buffer;                           \
+    if (bufp->allocated == MAX_BUF_SIZE)                                \
+      return REG_ESIZE;                                                 \
+    bufp->allocated <<= 1;                                              \
+    if (bufp->allocated > MAX_BUF_SIZE)                                 \
+      bufp->allocated = MAX_BUF_SIZE;                                   \
+    bufp->buffer = (unsigned char *) realloc (bufp->buffer, bufp->allocated);\
+    if (bufp->buffer == NULL)                                           \
+      return REG_ESPACE;                                                \
+    /* If the buffer moved, move all the pointers into it.  */          \
+    if (old_buffer != bufp->buffer)                                     \
+      {                                                                 \
+        b = (b - old_buffer) + bufp->buffer;                            \
+        begalt = (begalt - old_buffer) + bufp->buffer;                  \
+        if (fixup_alt_jump)                                             \
+          fixup_alt_jump = (fixup_alt_jump - old_buffer) + bufp->buffer;\
+        if (laststart)                                                  \
+          laststart = (laststart - old_buffer) + bufp->buffer;          \
+        if (pending_exact)                                              \
+          pending_exact = (pending_exact - old_buffer) + bufp->buffer;  \
+      }                                                                 \
+  } while (0)
+
+
+/* Since we have one byte reserved for the register number argument to
+   {start,stop}_memory, the maximum number of groups we can report
+   things about is what fits in that byte.  */
+#define MAX_REGNUM 255
+
+/* But patterns can have more than `MAX_REGNUM' registers.  We just
+   ignore the excess.  */
+typedef unsigned regnum_t;
+
+
+/* Macros for the compile stack.  */
+
+/* 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
+{
+  pattern_offset_t begalt_offset;
+  pattern_offset_t fixup_alt_jump;
+  pattern_offset_t inner_group_offset;
+  pattern_offset_t laststart_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)) / BYTEWIDTH]               \
+   |= 1 << (((unsigned char) c) % BYTEWIDTH))
+
+
+/* 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)                                           \
+   (STREQ (string, "alpha") || STREQ (string, "upper")                  \
+    || STREQ (string, "lower") || STREQ (string, "digit")               \
+    || STREQ (string, "alnum") || STREQ (string, "xdigit")              \
+    || STREQ (string, "space") || STREQ (string, "print")               \
+    || STREQ (string, "punct") || STREQ (string, "graph")               \
+    || STREQ (string, "cntrl") || STREQ (string, "blank"))
+
+/* `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 zero;
+     `re_nsub' is the number of subexpressions in PATTERN;
+     `not_bol' and `not_eol' are zero;
+
+   The `fastmap' and `newline_anchor' fields are neither
+   examined nor set.  */
+
+static reg_errcode_t
+regex_compile (pattern, size, syntax, bufp)
+     const char *pattern;
+     int size;
+     reg_syntax_t syntax;
+     struct re_pattern_buffer *bufp;
+{
+  /* 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;
+
+  /* Points to the end of the buffer, where we should append.  */
+  register unsigned char *b;
+
+  /* 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.  */
+  char *translate = bufp->translate;
+
+  /* Address of the count-byte of the most recently inserted `exactn'
+     command.  This makes it possible to tell if a new exact-match
+     character can be added to that command or if the character requires
+     a new `exactn' command.  */
+  unsigned char *pending_exact = 0;
+
+  /* Address of start of the most recently finished expression.
+     This tells, e.g., postfix * where to find the start of its
+     operand.  Reset at the beginning of groups and alternatives.  */
+  unsigned char *laststart = 0;
+
+  /* Address of beginning of regexp, or inside of last group.  */
+  unsigned char *begalt;
+
+  /* Place in the uncompiled pattern (i.e., the {) to
+     which to go back if the interval is invalid.  */
+  const char *beg_interval;
+
+  /* Address of the place where a forward jump should go to the end of
+     the containing expression.  Each alternative of an `or' -- except the
+     last -- ends with a forward jump of this sort.  */
+  unsigned char *fixup_alt_jump = 0;
+
+  /* Counts open-groups as they are encountered.  Remembered for the
+     matching close-group on the compile stack, so the same register
+     number is put in the stop_memory as the start_memory.  */
+  regnum_t regnum = 0;
+
+#ifdef DEBUG
+  DEBUG_PRINT1 ("\nCompiling pattern: ");
+  if (debug)
+    {
+      unsigned debug_count;
+
+      for (debug_count = 0; debug_count < size; debug_count++)
+        printchar (pattern[debug_count]);
+      putchar ('\n');
+    }
+#endif /* DEBUG */
+
+  /* Initialize the compile stack.  */
+  compile_stack.stack = TALLOC (INIT_COMPILE_STACK_SIZE, compile_stack_elt_t);
+  if (compile_stack.stack == NULL)
+    return REG_ESPACE;
+
+  compile_stack.size = INIT_COMPILE_STACK_SIZE;
+  compile_stack.avail = 0;
+
+  /* Initialize the pattern buffer.  */
+  bufp->syntax = syntax;
+  bufp->fastmap_accurate = 0;
+  bufp->not_bol = bufp->not_eol = 0;
+
+  /* Set `used' to zero, so that if we return an error, the pattern
+     printer (for debugging) will think there's no pattern.  We reset it
+     at the end.  */
+  bufp->used = 0;
+
+  /* Always count groups, whether or not bufp->no_sub is set.  */
+  bufp->re_nsub = 0;
+
+#if !defined (emacs) && !defined (SYNTAX_TABLE)
+  /* Initialize the syntax table.  */
+   init_syntax_once ();
+#endif
+
+  if (bufp->allocated == 0)
+    {
+      if (bufp->buffer)
+        { /* If zero allocated, but buffer is non-null, try to realloc
+             enough space.  This loses if buffer's address is bogus, but
+             that is the user's responsibility.  */
+          RETALLOC (bufp->buffer, INIT_BUF_SIZE, unsigned char);
+        }
+      else
+        { /* Caller did not allocate a buffer.  Do it for them.  */
+          bufp->buffer = TALLOC (INIT_BUF_SIZE, unsigned char);
+        }
+      if (!bufp->buffer) return REG_ESPACE;
+
+      bufp->allocated = INIT_BUF_SIZE;
+    }
+
+  begalt = b = bufp->buffer;
+
+  /* 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))
+              BUF_PUSH (begline);
+            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))
+               BUF_PUSH (endline);
+             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 (!laststart)
+            {
+              if (syntax & RE_CONTEXT_INVALID_OPS)
+                return REG_BADRPT;
+              else if (!(syntax & RE_CONTEXT_INDEP_OPS))
+                goto normal_char;
+            }
+
+          {
+            /* Are we optimizing this jump?  */
+            boolean keep_string_p = false;
+
+            /* 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 (!laststart)
+              break;
+
+            /* Now we know whether or not zero matches is allowed
+               and also whether or not two or more matches is allowed.  */
+            if (many_times_ok)
+              { /* More than one repetition is allowed, so put in at the
+                   end a backward relative jump from `b' to before the next
+                   jump we're going to put in below (which jumps from
+                   laststart to after this jump).
+
+                   But if we are at the `*' in the exact sequence `.*\n',
+                   insert an unconditional jump backwards to the .,
+                   instead of the beginning of the loop.  This way we only
+                   push a failure point once, instead of every time
+                   through the loop.  */
+                assert (p - 1 > pattern);
+
+                /* Allocate the space for the jump.  */
+                GET_BUFFER_SPACE (3);
+
+                /* We know we are not at the first character of the pattern,
+                   because laststart was nonzero.  And we've already
+                   incremented `p', by the way, to be the character after
+                   the `*'.  Do we have to do something analogous here
+                   for null bytes, because of RE_DOT_NOT_NULL?  */
+                if (TRANSLATE (*(p - 2)) == TRANSLATE ('.')
+                    && zero_times_ok
+                    && p < pend && TRANSLATE (*p) == TRANSLATE ('\n')
+                    && !(syntax & RE_DOT_NEWLINE))
+                  { /* We have .*\n.  */
+                    STORE_JUMP (jump, b, laststart);
+                    keep_string_p = true;
+                  }
+                else
+                  /* Anything else.  */
+                  STORE_JUMP (maybe_pop_jump, b, laststart - 3);
+
+                /* We've added more stuff to the buffer.  */
+                b += 3;
+              }
+
+            /* On failure, jump from laststart to b + 3, which will be the
+               end of the buffer after this jump is inserted.  */
+            GET_BUFFER_SPACE (3);
+            INSERT_JUMP (keep_string_p ? on_failure_keep_string_jump
+                                       : on_failure_jump,
+                         laststart, b + 3);
+            pending_exact = 0;
+            b += 3;
+
+            if (!zero_times_ok)
+              {
+                /* At least one repetition is required, so insert a
+                   `dummy_failure_jump' before the initial
+                   `on_failure_jump' instruction of the loop. This
+                   effects a skip over that instruction the first time
+                   we hit that loop.  */
+                GET_BUFFER_SPACE (3);
+                INSERT_JUMP (dummy_failure_jump, laststart, laststart + 6);
+                b += 3;
+              }
+            }
+          break;
+
+
+        case '.':
+          laststart = b;
+          BUF_PUSH (anychar);
+          break;
+
+
+        case '[':
+          {
+            boolean had_char_class = false;
+
+            if (p == pend) return REG_EBRACK;
+
+            /* Ensure that we have enough space to push a charset: the
+               opcode, the length count, and the bitset; 34 bytes in all.  */
+            GET_BUFFER_SPACE (34);
+
+            laststart = b;
+
+            /* We test `*p == '^' twice, instead of using an if
+               statement, so we only need one BUF_PUSH.  */
+            BUF_PUSH (*p == '^' ? charset_not : charset);
+            if (*p == '^')
+              p++;
+
+            /* Remember the first position in the bracket expression.  */
+            p1 = p;
+
+            /* Push the number of bytes in the bitmap.  */
+            BUF_PUSH ((1 << BYTEWIDTH) / BYTEWIDTH);
+
+            /* Clear the whole map.  */
+            bzero (b, (1 << BYTEWIDTH) / BYTEWIDTH);
+
+            /* charset_not matches newline according to a syntax bit.  */
+            if ((re_opcode_t) b[-2] == charset_not
+                && (syntax & RE_HAT_LISTS_NOT_NEWLINE))
+              SET_LIST_BIT ('\n');
+
+            /* 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);
+                    SET_LIST_BIT (c1);
+                    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)
+                  break;
+
+                /* 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 (&p, pend, translate, syntax, b);
+                    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 (&p, pend, translate, syntax, b);
+                    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 == ':')
+                  { /* Leave room for the null.  */
+                    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 = STREQ (str, "alnum");
+                        boolean is_alpha = STREQ (str, "alpha");
+                        boolean is_blank = STREQ (str, "blank");
+                        boolean is_cntrl = STREQ (str, "cntrl");
+                        boolean is_digit = STREQ (str, "digit");
+                        boolean is_graph = STREQ (str, "graph");
+                        boolean is_lower = STREQ (str, "lower");
+                        boolean is_print = STREQ (str, "print");
+                        boolean is_punct = STREQ (str, "punct");
+                        boolean is_space = STREQ (str, "space");
+                        boolean is_upper = STREQ (str, "upper");
+                        boolean is_xdigit = STREQ (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 << BYTEWIDTH; 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)))
+                            SET_LIST_BIT (ch);
+                          }
+                        had_char_class = true;
+                      }
+                    else
+                      {
+                        c1++;
+                        while (c1--)
+                          PATUNFETCH;
+                        SET_LIST_BIT ('[');
+                        SET_LIST_BIT (':');
+                        had_char_class = false;
+                      }
+                  }
+                else
+                  {
+                    had_char_class = false;
+                    SET_LIST_BIT (c);
+                  }
+              }
+
+            /* Discard any (non)matching list bytes that are all 0 at the
+               end of the map.  Decrease the map-length byte too.  */
+            while ((int) b[-1] > 0 && b[b[-1] - 1] == 0)
+              b[-1]--;
+            b += b[-1];
+          }
+          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:
+              bufp->re_nsub++;
+              regnum++;
+
+              if (COMPILE_STACK_FULL)
+                {
+                  RETALLOC (compile_stack.stack, compile_stack.size << 1,
+                            compile_stack_elt_t);
+                  if (compile_stack.stack == NULL) return REG_ESPACE;
+
+                  compile_stack.size <<= 1;
+                }
+
+              /* These are the values to restore when we hit end of this
+                 group.  They are all relative offsets, so that if the
+                 whole pattern moves because of realloc, they will still
+                 be valid.  */
+              COMPILE_STACK_TOP.begalt_offset = begalt - bufp->buffer;
+              COMPILE_STACK_TOP.fixup_alt_jump
+                = fixup_alt_jump ? fixup_alt_jump - bufp->buffer + 1 : 0;
+              COMPILE_STACK_TOP.laststart_offset = b - bufp->buffer;
+              COMPILE_STACK_TOP.regnum = regnum;
+
+              /* We will eventually replace the 0 with the number of
+                 groups inner to this one.  But do not push a
+                 start_memory for groups beyond the last one we can
+                 represent in the compiled pattern.  */
+              if (regnum <= MAX_REGNUM)
+                {
+                  COMPILE_STACK_TOP.inner_group_offset = b - bufp->buffer + 2;
+                  BUF_PUSH_3 (start_memory, regnum, 0);
+                }
+
+              compile_stack.avail++;
+
+              fixup_alt_jump = 0;
+              laststart = 0;
+              begalt = b;
+              /* If we've reached MAX_REGNUM groups, then this open
+                 won't actually generate any code, so we'll have to
+                 clear pending_exact explicitly.  */
+              pending_exact = 0;
+              break;
+
+
+            case ')':
+              if (syntax & RE_NO_BK_PARENS) goto normal_backslash;
+
+              if (COMPILE_STACK_EMPTY)
+              {
+                if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
+                  goto normal_backslash;
+                else
+                  return REG_ERPAREN;
+              }
+
+            handle_close:
+              if (fixup_alt_jump)
+                { /* Push a dummy failure point at the end of the
+                     alternative for a possible future
+                     `pop_failure_jump' to pop.  See comments at
+                     `push_dummy_failure' in `re_match_2'.  */
+                  BUF_PUSH (push_dummy_failure);
+
+                  /* We allocated space for this jump when we assigned
+                     to `fixup_alt_jump', in the `handle_alt' case below.  */
+                  STORE_JUMP (jump_past_alt, fixup_alt_jump, b - 1);
+                }
+
+              /* 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''.  */
+              assert (compile_stack.avail != 0);
+              {
+                /* 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;
+
+                compile_stack.avail--;
+                begalt = bufp->buffer + COMPILE_STACK_TOP.begalt_offset;
+                fixup_alt_jump
+                  = COMPILE_STACK_TOP.fixup_alt_jump
+                    ? bufp->buffer + COMPILE_STACK_TOP.fixup_alt_jump - 1
+                    : 0;
+                laststart = bufp->buffer + COMPILE_STACK_TOP.laststart_offset;
+                this_group_regnum = COMPILE_STACK_TOP.regnum;
+                /* If we've reached MAX_REGNUM groups, then this open
+                   won't actually generate any code, so we'll have to
+                   clear pending_exact explicitly.  */
+                pending_exact = 0;
+
+                /* We're at the end of the group, so now we know how many
+                   groups were inside this one.  */
+                if (this_group_regnum <= MAX_REGNUM)
+                  {
+                    unsigned char *inner_group_loc
+                      = bufp->buffer + COMPILE_STACK_TOP.inner_group_offset;
+
+                    *inner_group_loc = regnum - this_group_regnum;
+                    BUF_PUSH_3 (stop_memory, this_group_regnum,
+                                regnum - this_group_regnum);
+                  }
+              }
+              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;
+
+              /* Insert before the previous alternative a jump which
+                 jumps to this alternative if the former fails.  */
+              GET_BUFFER_SPACE (3);
+              INSERT_JUMP (on_failure_jump, begalt, b + 6);
+              pending_exact = 0;
+              b += 3;
+
+              /* The alternative before this one has a jump after it
+                 which gets executed if it gets matched.  Adjust that
+                 jump so it will jump to this alternative's analogous
+                 jump (put in below, which in turn will jump to the next
+                 (if any) alternative's such jump, etc.).  The last such
+                 jump jumps to the correct final destination.  A picture:
+                          _____ _____
+                          |   | |   |
+                          |   v |   v
+                         a | b   | c
+
+                 If we are at `b', then fixup_alt_jump right now points to a
+                 three-byte space after `a'.  We'll put in the jump, set
+                 fixup_alt_jump to right after `b', and leave behind three
+                 bytes which we'll fill in when we get to after `c'.  */
+
+              if (fixup_alt_jump)
+                STORE_JUMP (jump_past_alt, fixup_alt_jump, b);
+
+              /* Mark and leave space for a jump after this alternative,
+                 to be filled in later either by next alternative or
+                 when know we're at the end of a series of alternatives.  */
+              fixup_alt_jump = b;
+              GET_BUFFER_SPACE (3);
+              b += 3;
+
+              laststart = 0;
+              begalt = b;
+              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 (!laststart)
+                  {
+                    if (syntax & RE_CONTEXT_INVALID_OPS)
+                      return REG_BADRPT;
+                    else if (syntax & RE_CONTEXT_INDEP_OPS)
+                      laststart = b;
+                    else
+                      goto unfetch_interval;
+                  }
+
+                /* If the upper bound is zero, don't want to succeed at
+                   all; jump from `laststart' to `b + 3', which will be
+                   the end of the buffer after we insert the jump.  */
+                 if (upper_bound == 0)
+                   {
+                     GET_BUFFER_SPACE (3);
+                     INSERT_JUMP (jump, laststart, b + 3);
+                     b += 3;
+                   }
+
+                 /* Otherwise, we have a nontrivial interval.  When
+                    we're all done, the pattern will look like:
+                      set_number_at <jump count> <upper bound>
+                      set_number_at <succeed_n count> <lower bound>
+                      succeed_n <after jump addr> <succed_n count>
+                      <body of loop>
+                      jump_n <succeed_n addr> <jump count>
+                    (The upper bound and `jump_n' are omitted if
+                    `upper_bound' is 1, though.)  */
+                 else
+                   { /* If the upper bound is > 1, we need to insert
+                        more at the end of the loop.  */
+                     unsigned nbytes = 10 + (upper_bound > 1) * 10;
+
+                     GET_BUFFER_SPACE (nbytes);
+
+                     /* Initialize lower bound of the `succeed_n', even
+                        though it will be set during matching by its
+                        attendant `set_number_at' (inserted next),
+                        because `re_compile_fastmap' needs to know.
+                        Jump to the `jump_n' we might insert below.  */
+                     INSERT_JUMP2 (succeed_n, laststart,
+                                   b + 5 + (upper_bound > 1) * 5,
+                                   lower_bound);
+                     b += 5;
+
+                     /* Code to initialize the lower bound.  Insert
+                        before the `succeed_n'.  The `5' is the last two
+                        bytes of this `set_number_at', plus 3 bytes of
+                        the following `succeed_n'.  */
+                     insert_op2 (set_number_at, laststart, 5, lower_bound, b);
+                     b += 5;
+
+                     if (upper_bound > 1)
+                       { /* More than one repetition is allowed, so
+                            append a backward jump to the `succeed_n'
+                            that starts this interval.
+
+                            When we've reached this during matching,
+                            we'll have matched the interval once, so
+                            jump back only `upper_bound - 1' times.  */
+                         STORE_JUMP2 (jump_n, b, laststart + 5,
+                                      upper_bound - 1);
+                         b += 5;
+
+                         /* The location we want to set is the second
+                            parameter of the `jump_n'; that is `b-2' as
+                            an absolute address.  `laststart' will be
+                            the `set_number_at' we're about to insert;
+                            `laststart+3' the number to set, the source
+                            for the relative address.  But we are
+                            inserting into the middle of the pattern --
+                            so everything is getting moved up by 5.
+                            Conclusion: (b - 2) - (laststart + 3) + 5,
+                            i.e., b - laststart.
+
+                            We insert this at the beginning of the loop
+                            so that if we fail during matching, we'll
+                            reinitialize the bounds.  */
+                         insert_op2 (set_number_at, laststart, b - laststart,
+                                     upper_bound - 1, b);
+                         b += 5;
+                       }
+                   }
+                pending_exact = 0;
+                beg_interval = NULL;
+              }
+              break;
+
+            unfetch_interval:
+              /* If an invalid interval, match the characters as literals.  */
+               assert (beg_interval);
+               p = beg_interval;
+               beg_interval = NULL;
+
+               /* 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 '=':
+              BUF_PUSH (at_dot);
+              break;
+
+            case 's':
+              laststart = b;
+              PATFETCH (c);
+              BUF_PUSH_2 (syntaxspec, syntax_spec_code[c]);
+              break;
+
+            case 'S':
+              laststart = b;
+              PATFETCH (c);
+              BUF_PUSH_2 (notsyntaxspec, syntax_spec_code[c]);
+              break;
+#endif /* emacs */
+
+
+            case 'w':
+              laststart = b;
+              BUF_PUSH (wordchar);
+              break;
+
+
+            case 'W':
+              laststart = b;
+              BUF_PUSH (notwordchar);
+              break;
+
+
+            case '<':
+              BUF_PUSH (wordbeg);
+              break;
+
+            case '>':
+              BUF_PUSH (wordend);
+              break;
+
+            case 'b':
+              BUF_PUSH (wordbound);
+              break;
+
+            case 'B':
+              BUF_PUSH (notwordbound);
+              break;
+
+            case '`':
+              BUF_PUSH (begbuf);
+              break;
+
+            case '\'':
+              BUF_PUSH (endbuf);
+              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))
+                goto normal_char;
+
+              laststart = b;
+              BUF_PUSH_2 (duplicate, c1);
+              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:
+              /* If no exactn currently being built.  */
+          if (!pending_exact
+
+              /* If last exactn not at current position.  */
+              || pending_exact + *pending_exact + 1 != b
+
+              /* We have only one byte following the exactn for the count.  */
+              || *pending_exact == (1 << BYTEWIDTH) - 1
+
+              /* If followed by a repetition operator.  */
+              || *p == '*' || *p == '^'
+              || ((syntax & RE_BK_PLUS_QM)
+                  ? *p == '\\' && (p[1] == '+' || p[1] == '?')
+                  : (*p == '+' || *p == '?'))
+              || ((syntax & RE_INTERVALS)
+                  && ((syntax & RE_NO_BK_BRACES)
+                      ? *p == '{'
+                      : (p[0] == '\\' && p[1] == '{'))))
+            {
+              /* Start building a new exactn.  */
+
+              laststart = b;
+
+              BUF_PUSH_2 (exactn, 0);
+              pending_exact = b - 1;
+            }
+
+          BUF_PUSH (c);
+          (*pending_exact)++;
+          break;
+        } /* switch (c) */
+    } /* while p != pend */
+
+
+  /* Through the pattern now.  */
+
+  if (fixup_alt_jump)
+    STORE_JUMP (jump_past_alt, fixup_alt_jump, b);
+
+  if (!COMPILE_STACK_EMPTY)
+    return REG_EPAREN;
+
+  free (compile_stack.stack);
+
+  /* We have succeeded; set the length of the buffer.  */
+  bufp->used = b - bufp->buffer;
+
+#ifdef DEBUG
+  if (debug)
+    {
+      DEBUG_PRINT1 ("\nCompiled pattern: ");
+      print_compiled_pattern (bufp);
+    }
+#endif /* DEBUG */
+
+  return REG_NOERROR;
+} /* regex_compile */
+
+/* Subroutines for `regex_compile'.  */
+
+/* Store OP at LOC followed by two-byte integer parameter ARG.  */
+
+static void
+store_op1 (op, loc, arg)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg;
+{
+  *loc = (unsigned char) op;
+  STORE_NUMBER (loc + 1, arg);
+}
+
+
+/* Like `store_op1', but for two two-byte parameters ARG1 and ARG2.  */
+
+static void
+store_op2 (op, loc, arg1, arg2)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg1, arg2;
+{
+  *loc = (unsigned char) op;
+  STORE_NUMBER (loc + 1, arg1);
+  STORE_NUMBER (loc + 3, arg2);
+}
+
+
+/* Copy the bytes from LOC to END to open up three bytes of space at LOC
+   for OP followed by two-byte integer parameter ARG.  */
+
+static void
+insert_op1 (op, loc, arg, end)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg;
+    unsigned char *end;
+{
+  register unsigned char *pfrom = end;
+  register unsigned char *pto = end + 3;
+
+  while (pfrom != loc)
+    *--pto = *--pfrom;
+
+  store_op1 (op, loc, arg);
+}
+
+
+/* Like `insert_op1', but for two two-byte parameters ARG1 and ARG2.  */
+
+static void
+insert_op2 (op, loc, arg1, arg2, end)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg1, arg2;
+    unsigned char *end;
+{
+  register unsigned char *pfrom = end;
+  register unsigned char *pto = end + 5;
+
+  while (pfrom != loc)
+    *--pto = *--pfrom;
+
+  store_op2 (op, loc, arg1, arg2);
+}
+
+
+/* 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 ^.  */
+
+static boolean
+at_begline_loc_p (pattern, p, syntax)
+    const char *pattern, *p;
+    reg_syntax_t syntax;
+{
+  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'.  */
+
+static boolean
+at_endline_loc_p (p, pend, syntax)
+    const char *p, *pend;
+    int syntax;
+{
+  const char *next = p;
+  boolean next_backslash = *next == '\\';
+  const char *next_next = p + 1 < pend ? p + 1 : NULL;
+
+  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 == '|');
+}
+
+
+/* Returns true if REGNUM is in one of COMPILE_STACK's elements and
+   false if it's not.  */
+
+static boolean
+group_in_compile_stack (compile_stack, regnum)
+    compile_stack_type compile_stack;
+    regnum_t regnum;
+{
+  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.  */
+
+static reg_errcode_t
+compile_range (p_ptr, pend, translate, syntax, b)
+    const char **p_ptr, *pend;
+    char *translate;
+    reg_syntax_t syntax;
+    unsigned char *b;
+{
+  unsigned this_char;
+
+  const char *p = *p_ptr;
+  int range_start, range_end;
+
+  if (p == pend)
+    return REG_ERANGE;
+
+  /* Even though the pattern is a signed `char *', we need to fetch
+     with unsigned char *'s; if the high bit of the pattern character
+     is set, the range endpoints will be negative if we fetch using a
+     signed char *.
+
+     We also want to fetch the endpoints without translating them; the
+     appropriate translation is done in the bit-setting loop below.  */
+  range_start = ((unsigned char *) p)[-2];
+  range_end   = ((unsigned char *) p)[0];
+
+  /* Have to increment the pointer into the pattern string, so the
+     caller isn't still at the ending character.  */
+  (*p_ptr)++;
+
+  /* If the start is after the end, the range is empty.  */
+  if (range_start > range_end)
+    return syntax & RE_NO_EMPTY_RANGES ? REG_ERANGE : REG_NOERROR;
+
+  /* Here we see why `this_char' has to be larger than an `unsigned
+     char' -- the range is inclusive, so if `range_end' == 0xff
+     (assuming 8-bit characters), we would otherwise go into an infinite
+     loop, since all characters <= 0xff.  */
+  for (this_char = range_start; this_char <= range_end; this_char++)
+    {
+      SET_LIST_BIT (TRANSLATE (this_char));
+    }
+
+  return REG_NOERROR;
+}
+
+/* Failure stack declarations and macros; both re_compile_fastmap and
+   re_match_2 use a failure stack.  These have to be macros because of
+   REGEX_ALLOCATE.  */
+
+
+/* Number of failure points for which to initially allocate space
+   when matching.  If this number is exceeded, we allocate more
+   space, so it is not a hard limit.  */
+#ifndef INIT_FAILURE_ALLOC
+#define INIT_FAILURE_ALLOC 5
+#endif
+
+/* Roughly the maximum number of failure points on the stack.  Would be
+   exactly that if always used MAX_FAILURE_SPACE each time we failed.
+   This is a variable only so users of regex can assign to it; we never
+   change it ourselves.  */
+int re_max_failures = 2000;
+
+typedef const unsigned char *fail_stack_elt_t;
+
+typedef struct
+{
+  fail_stack_elt_t *stack;
+  unsigned size;
+  unsigned avail;                       /* Offset of next open position.  */
+} fail_stack_type;
+
+#define FAIL_STACK_EMPTY()     (fail_stack.avail == 0)
+#define FAIL_STACK_PTR_EMPTY() (fail_stack_ptr->avail == 0)
+#define FAIL_STACK_FULL()      (fail_stack.avail == fail_stack.size)
+#define FAIL_STACK_TOP()       (fail_stack.stack[fail_stack.avail])
+
+
+/* Initialize `fail_stack'.  Do `return -2' if the alloc fails.  */
+
+#define INIT_FAIL_STACK()                                               \
+  do {                                                                  \
+    fail_stack.stack = (fail_stack_elt_t *)                             \
+      REGEX_ALLOCATE (INIT_FAILURE_ALLOC * sizeof (fail_stack_elt_t));  \
+                                                                        \
+    if (fail_stack.stack == NULL)                                       \
+      return -2;                                                        \
+                                                                        \
+    fail_stack.size = INIT_FAILURE_ALLOC;                               \
+    fail_stack.avail = 0;                                               \
+  } while (0)
+
+
+/* Double the size of FAIL_STACK, up to approximately `re_max_failures' items.
+
+   Return 1 if succeeds, and 0 if either ran out of memory
+   allocating space for it or it was already too large.
+
+   REGEX_REALLOCATE requires `destination' be declared.   */
+
+#define DOUBLE_FAIL_STACK(fail_stack)                                   \
+  ((fail_stack).size > re_max_failures * MAX_FAILURE_ITEMS              \
+   ? 0                                                                  \
+   : ((fail_stack).stack = (fail_stack_elt_t *)                         \
+        REGEX_REALLOCATE ((fail_stack).stack,                           \
+          (fail_stack).size * sizeof (fail_stack_elt_t),                \
+          ((fail_stack).size << 1) * sizeof (fail_stack_elt_t)),        \
+                                                                        \
+      (fail_stack).stack == NULL                                        \
+      ? 0                                                               \
+      : ((fail_stack).size <<= 1,                                       \
+         1)))
+
+
+/* Push PATTERN_OP on FAIL_STACK.
+
+   Return 1 if was able to do so and 0 if ran out of memory allocating
+   space to do so.  */
+#define PUSH_PATTERN_OP(pattern_op, fail_stack)                         \
+  ((FAIL_STACK_FULL ()                                                  \
+    && !DOUBLE_FAIL_STACK (fail_stack))                                 \
+    ? 0                                                                 \
+    : ((fail_stack).stack[(fail_stack).avail++] = pattern_op,           \
+       1))
+
+/* This pushes an item onto the failure stack.  Must be a four-byte
+   value.  Assumes the variable `fail_stack'.  Probably should only
+   be called from within `PUSH_FAILURE_POINT'.  */
+#define PUSH_FAILURE_ITEM(item)                                         \
+  fail_stack.stack[fail_stack.avail++] = (fail_stack_elt_t) item
+
+/* The complement operation.  Assumes `fail_stack' is nonempty.  */
+#define POP_FAILURE_ITEM() fail_stack.stack[--fail_stack.avail]
+
+/* Used to omit pushing failure point id's when we're not debugging.  */
+#ifdef DEBUG
+#define DEBUG_PUSH PUSH_FAILURE_ITEM
+#define DEBUG_POP(item_addr) *(item_addr) = POP_FAILURE_ITEM ()
+#else
+#define DEBUG_PUSH(item)
+#define DEBUG_POP(item_addr)
+#endif
+
+
+/* Push the information about the state we will need
+   if we ever fail back to it.
+
+   Requires variables fail_stack, regstart, regend, reg_info, and
+   num_regs be declared.  DOUBLE_FAIL_STACK requires `destination' be
+   declared.
+
+   Does `return FAILURE_CODE' if runs out of memory.  */
+
+#define PUSH_FAILURE_POINT(pattern_place, string_place, failure_code)   \
+  do {                                                                  \
+    char *destination;                                                  \
+    /* Must be int, so when we don't save any registers, the arithmetic \
+       of 0 + -1 isn't done as unsigned.  */                            \
+    int this_reg;                                                       \
+                                                                        \
+    DEBUG_STATEMENT (failure_id++);                                     \
+    DEBUG_STATEMENT (nfailure_points_pushed++);                         \
+    DEBUG_PRINT2 ("\nPUSH_FAILURE_POINT #%u:\n", failure_id);           \
+    DEBUG_PRINT2 ("  Before push, next avail: %d\n", (fail_stack).avail);\
+    DEBUG_PRINT2 ("                     size: %d\n", (fail_stack).size);\
+                                                                        \
+    DEBUG_PRINT2 ("  slots needed: %d\n", NUM_FAILURE_ITEMS);           \
+    DEBUG_PRINT2 ("     available: %d\n", REMAINING_AVAIL_SLOTS);       \
+                                                                        \
+    /* Ensure we have enough space allocated for what we will push.  */ \
+    while (REMAINING_AVAIL_SLOTS < NUM_FAILURE_ITEMS)                   \
+      {                                                                 \
+        if (!DOUBLE_FAIL_STACK (fail_stack))                    \
+          return failure_code;                                          \
+                                                                        \
+        DEBUG_PRINT2 ("\n  Doubled stack; size now: %d\n",              \
+                       (fail_stack).size);                              \
+        DEBUG_PRINT2 ("  slots available: %d\n", REMAINING_AVAIL_SLOTS);\
+      }                                                                 \
+                                                                        \
+    /* Push the info, starting with the registers.  */                  \
+    DEBUG_PRINT1 ("\n");                                                \
+                                                                        \
+    for (this_reg = lowest_active_reg; this_reg <= highest_active_reg;  \
+         this_reg++)                                                    \
+      {                                                                 \
+        DEBUG_PRINT2 ("  Pushing reg: %d\n", this_reg);                 \
+        DEBUG_STATEMENT (num_regs_pushed++);                            \
+                                                                        \
+        DEBUG_PRINT2 ("    start: 0x%x\n", regstart[this_reg]);         \
+        PUSH_FAILURE_ITEM (regstart[this_reg]);                         \
+                                                                        \
+        DEBUG_PRINT2 ("    end: 0x%x\n", regend[this_reg]);             \
+        PUSH_FAILURE_ITEM (regend[this_reg]);                           \
+                                                                        \
+        DEBUG_PRINT2 ("    info: 0x%x\n      ", reg_info[this_reg]);    \
+        DEBUG_PRINT2 (" match_null=%d",                                 \
+                      REG_MATCH_NULL_STRING_P (reg_info[this_reg]));    \
+        DEBUG_PRINT2 (" active=%d", IS_ACTIVE (reg_info[this_reg]));    \
+        DEBUG_PRINT2 (" matched_something=%d",                          \
+                      MATCHED_SOMETHING (reg_info[this_reg]));          \
+        DEBUG_PRINT2 (" ever_matched=%d",                               \
+                      EVER_MATCHED_SOMETHING (reg_info[this_reg]));     \
+        DEBUG_PRINT1 ("\n");                                            \
+        PUSH_FAILURE_ITEM (reg_info[this_reg].word);                    \
+      }                                                                 \
+                                                                        \
+    DEBUG_PRINT2 ("  Pushing  low active reg: %d\n", lowest_active_reg);\
+    PUSH_FAILURE_ITEM (lowest_active_reg);                              \
+                                                                        \
+    DEBUG_PRINT2 ("  Pushing high active reg: %d\n", highest_active_reg);\
+    PUSH_FAILURE_ITEM (highest_active_reg);                             \
+                                                                        \
+    DEBUG_PRINT2 ("  Pushing pattern 0x%x: ", pattern_place);           \
+    DEBUG_PRINT_COMPILED_PATTERN (bufp, pattern_place, pend);           \
+    PUSH_FAILURE_ITEM (pattern_place);                                  \
+                                                                        \
+    DEBUG_PRINT2 ("  Pushing string 0x%x: `", string_place);            \
+    DEBUG_PRINT_DOUBLE_STRING (string_place, string1, size1, string2,   \
+                                 size2);                                \
+    DEBUG_PRINT1 ("'\n");                                               \
+    PUSH_FAILURE_ITEM (string_place);                                   \
+                                                                        \
+    DEBUG_PRINT2 ("  Pushing failure id: %u\n", failure_id);            \
+    DEBUG_PUSH (failure_id);                                            \
+  } while (0)
+
+/* This is the number of items that are pushed and popped on the stack
+   for each register.  */
+#define NUM_REG_ITEMS  3
+
+/* Individual items aside from the registers.  */
+#ifdef DEBUG
+#define NUM_NONREG_ITEMS 5 /* Includes failure point id.  */
+#else
+#define NUM_NONREG_ITEMS 4
+#endif
+
+/* We push at most this many items on the stack.  */
+#define MAX_FAILURE_ITEMS ((num_regs - 1) * NUM_REG_ITEMS + NUM_NONREG_ITEMS)
+
+/* We actually push this many items.  */
+#define NUM_FAILURE_ITEMS                                               \
+  ((highest_active_reg - lowest_active_reg + 1) * NUM_REG_ITEMS         \
+    + NUM_NONREG_ITEMS)
+
+/* How many items can still be added to the stack without overflowing it.  */
+#define REMAINING_AVAIL_SLOTS ((fail_stack).size - (fail_stack).avail)
+
+
+/* Pops what PUSH_FAIL_STACK pushes.
+
+   We restore into the parameters, all of which should be lvalues:
+     STR -- the saved data position.
+     PAT -- the saved pattern position.
+     LOW_REG, HIGH_REG -- the highest and lowest active registers.
+     REGSTART, REGEND -- arrays of string positions.
+     REG_INFO -- array of information about each subexpression.
+
+   Also assumes the variables `fail_stack' and (if debugging), `bufp',
+   `pend', `string1', `size1', `string2', and `size2'.  */
+
+#define POP_FAILURE_POINT(str, pat, low_reg, high_reg, regstart, regend, reg_info)\
+{                                                                       \
+  DEBUG_STATEMENT (fail_stack_elt_t failure_id;)                        \
+  int this_reg;                                                         \
+  const unsigned char *string_temp;                                     \
+                                                                        \
+  assert (!FAIL_STACK_EMPTY ());                                        \
+                                                                        \
+  /* Remove failure points and point to how many regs pushed.  */       \
+  DEBUG_PRINT1 ("POP_FAILURE_POINT:\n");                                \
+  DEBUG_PRINT2 ("  Before pop, next avail: %d\n", fail_stack.avail);    \
+  DEBUG_PRINT2 ("                    size: %d\n", fail_stack.size);     \
+                                                                        \
+  assert (fail_stack.avail >= NUM_NONREG_ITEMS);                        \
+                                                                        \
+  DEBUG_POP (&failure_id);                                              \
+  DEBUG_PRINT2 ("  Popping failure id: %u\n", failure_id);              \
+                                                                        \
+  /* If the saved string location is NULL, it came from an              \
+     on_failure_keep_string_jump opcode, and we want to throw away the  \
+     saved NULL, thus retaining our current position in the string.  */ \
+  string_temp = POP_FAILURE_ITEM ();                                    \
+  if (string_temp != NULL)                                              \
+    str = (const char *) string_temp;                                   \
+                                                                        \
+  DEBUG_PRINT2 ("  Popping string 0x%x: `", str);                       \
+  DEBUG_PRINT_DOUBLE_STRING (str, string1, size1, string2, size2);      \
+  DEBUG_PRINT1 ("'\n");                                                 \
+                                                                        \
+  pat = (unsigned char *) POP_FAILURE_ITEM ();                          \
+  DEBUG_PRINT2 ("  Popping pattern 0x%x: ", pat);                       \
+  DEBUG_PRINT_COMPILED_PATTERN (bufp, pat, pend);                       \
+                                                                        \
+  /* Restore register info.  */                                         \
+  high_reg = (unsigned) POP_FAILURE_ITEM ();                            \
+  DEBUG_PRINT2 ("  Popping high active reg: %d\n", high_reg);           \
+                                                                        \
+  low_reg = (unsigned) POP_FAILURE_ITEM ();                             \
+  DEBUG_PRINT2 ("  Popping  low active reg: %d\n", low_reg);            \
+                                                                        \
+  for (this_reg = high_reg; this_reg >= low_reg; this_reg--)            \
+    {                                                                   \
+      DEBUG_PRINT2 ("    Popping reg: %d\n", this_reg);                 \
+                                                                        \
+      reg_info[this_reg].word = POP_FAILURE_ITEM ();                    \
+      DEBUG_PRINT2 ("      info: 0x%x\n", reg_info[this_reg]);          \
+                                                                        \
+      regend[this_reg] = (const char *) POP_FAILURE_ITEM ();            \
+      DEBUG_PRINT2 ("      end: 0x%x\n", regend[this_reg]);             \
+                                                                        \
+      regstart[this_reg] = (const char *) POP_FAILURE_ITEM ();          \
+      DEBUG_PRINT2 ("      start: 0x%x\n", regstart[this_reg]);         \
+    }                                                                   \
+                                                                        \
+  DEBUG_STATEMENT (nfailure_points_popped++);                           \
+} /* POP_FAILURE_POINT */
+
+/* re_compile_fastmap computes a ``fastmap'' for the compiled pattern in
+   BUFP.  A fastmap records which of the (1 << BYTEWIDTH) possible
+   characters can start a string that matches the pattern.  This fastmap
+   is used by re_search to skip quickly over impossible starting points.
+
+   The caller must supply the address of a (1 << BYTEWIDTH)-byte data
+   area as BUFP->fastmap.
+
+   We set the `fastmap', `fastmap_accurate', and `can_be_null' fields in
+   the pattern buffer.
+
+   Returns 0 if we succeed, -2 if an internal error.   */
+
+int
+re_compile_fastmap (bufp)
+     struct re_pattern_buffer *bufp;
+{
+  int j, k;
+  fail_stack_type fail_stack;
+#ifndef REGEX_MALLOC
+  char *destination;
+#endif
+  /* We don't push any register information onto the failure stack.  */
+  unsigned num_regs = 0;
+
+  register char *fastmap = bufp->fastmap;
+  unsigned char *pattern = bufp->buffer;
+  unsigned long size = bufp->used;
+  const unsigned char *p = pattern;
+  register unsigned char *pend = pattern + size;
+
+  /* Assume that each path through the pattern can be null until
+     proven otherwise.  We set this false at the bottom of switch
+     statement, to which we get only if a particular path doesn't
+     match the empty string.  */
+  boolean path_can_be_null = true;
+
+  /* We aren't doing a `succeed_n' to begin with.  */
+  boolean succeed_n_p = false;
+
+  assert (fastmap != NULL && p != NULL);
+
+  INIT_FAIL_STACK ();
+  bzero (fastmap, 1 << BYTEWIDTH);  /* Assume nothing's valid.  */
+  bufp->fastmap_accurate = 1;       /* It will be when we're done.  */
+  bufp->can_be_null = 0;
+
+  while (p != pend || !FAIL_STACK_EMPTY ())
+    {
+      if (p == pend)
+        {
+          bufp->can_be_null |= path_can_be_null;
+
+          /* Reset for next path.  */
+          path_can_be_null = true;
+
+          p = fail_stack.stack[--fail_stack.avail];
+        }
+
+      /* We should never be about to go beyond the end of the pattern.  */
+      assert (p < pend);
+
+#ifdef SWITCH_ENUM_BUG
+      switch ((int) ((re_opcode_t) *p++))
+#else
+      switch ((re_opcode_t) *p++)
+#endif
+        {
+
+        /* I guess the idea here is to simply not bother with a fastmap
+           if a backreference is used, since it's too hard to figure out
+           the fastmap for the corresponding group.  Setting
+           `can_be_null' stops `re_search_2' from using the fastmap, so
+           that is all we do.  */
+        case duplicate:
+          bufp->can_be_null = 1;
+          return 0;
+
+
+      /* Following are the cases which match a character.  These end
+         with `break'.  */
+
+        case exactn:
+          fastmap[p[1]] = 1;
+          break;
+
+
+        case charset:
+          for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
+            if (p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH)))
+              fastmap[j] = 1;
+          break;
+
+
+        case charset_not:
+          /* Chars beyond end of map must be allowed.  */
+          for (j = *p * BYTEWIDTH; j < (1 << BYTEWIDTH); j++)
+            fastmap[j] = 1;
+
+          for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
+            if (!(p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH))))
+              fastmap[j] = 1;
+          break;
+
+
+        case wordchar:
+          for (j = 0; j < (1 << BYTEWIDTH); j++)
+            if (SYNTAX (j) == Sword)
+              fastmap[j] = 1;
+          break;
+
+
+        case notwordchar:
+          for (j = 0; j < (1 << BYTEWIDTH); j++)
+            if (SYNTAX (j) != Sword)
+              fastmap[j] = 1;
+          break;
+
+
+        case anychar:
+          /* `.' matches anything ...  */
+          for (j = 0; j < (1 << BYTEWIDTH); j++)
+            fastmap[j] = 1;
+
+          /* ... except perhaps newline.  */
+          if (!(bufp->syntax & RE_DOT_NEWLINE))
+            fastmap['\n'] = 0;
+
+          /* Return if we have already set `can_be_null'; if we have,
+             then the fastmap is irrelevant.  Something's wrong here.  */
+          else if (bufp->can_be_null)
+            return 0;
+
+          /* Otherwise, have to check alternative paths.  */
+          break;
+
+
+#ifdef emacs
+        case syntaxspec:
+          k = *p++;
+          for (j = 0; j < (1 << BYTEWIDTH); j++)
+            if (SYNTAX (j) == (enum syntaxcode) k)
+              fastmap[j] = 1;
+          break;
+
+
+        case notsyntaxspec:
+          k = *p++;
+          for (j = 0; j < (1 << BYTEWIDTH); j++)
+            if (SYNTAX (j) != (enum syntaxcode) k)
+              fastmap[j] = 1;
+          break;
+
+
+      /* All cases after this match the empty string.  These end with
+         `continue'.  */
+
+
+        case before_dot:
+        case at_dot:
+        case after_dot:
+          continue;
+#endif /* not emacs */
+
+
+        case no_op:
+        case begline:
+        case endline:
+        case begbuf:
+        case endbuf:
+        case wordbound:
+        case notwordbound:
+        case wordbeg:
+        case wordend:
+        case push_dummy_failure:
+          continue;
+
+
+        case jump_n:
+        case pop_failure_jump:
+        case maybe_pop_jump:
+        case jump:
+        case jump_past_alt:
+        case dummy_failure_jump:
+          EXTRACT_NUMBER_AND_INCR (j, p);
+          p += j;
+          if (j > 0)
+            continue;
+
+          /* Jump backward implies we just went through the body of a
+             loop and matched nothing.  Opcode jumped to should be
+             `on_failure_jump' or `succeed_n'.  Just treat it like an
+             ordinary jump.  For a * loop, it has pushed its failure
+             point already; if so, discard that as redundant.  */
+          if ((re_opcode_t) *p != on_failure_jump
+              && (re_opcode_t) *p != succeed_n)
+            continue;
+
+          p++;
+          EXTRACT_NUMBER_AND_INCR (j, p);
+          p += j;
+
+          /* If what's on the stack is where we are now, pop it.  */
+          if (!FAIL_STACK_EMPTY ()
+              && fail_stack.stack[fail_stack.avail - 1] == p)
+            fail_stack.avail--;
+
+          continue;
+
+
+        case on_failure_jump:
+        case on_failure_keep_string_jump:
+        handle_on_failure_jump:
+          EXTRACT_NUMBER_AND_INCR (j, p);
+
+          /* For some patterns, e.g., `(a?)?', `p+j' here points to the
+             end of the pattern.  We don't want to push such a point,
+             since when we restore it above, entering the switch will
+             increment `p' past the end of the pattern.  We don't need
+             to push such a point since we obviously won't find any more
+             fastmap entries beyond `pend'.  Such a pattern can match
+             the null string, though.  */
+          if (p + j < pend)
+            {
+              if (!PUSH_PATTERN_OP (p + j, fail_stack))
+                return -2;
+            }
+          else
+            bufp->can_be_null = 1;
+
+          if (succeed_n_p)
+            {
+              EXTRACT_NUMBER_AND_INCR (k, p);   /* Skip the n.  */
+              succeed_n_p = false;
+            }
+
+          continue;
+
+
+        case succeed_n:
+          /* Get to the number of times to succeed.  */
+          p += 2;
+
+          /* Increment p past the n for when k != 0.  */
+          EXTRACT_NUMBER_AND_INCR (k, p);
+          if (k == 0)
+            {
+              p -= 4;
+              succeed_n_p = true;  /* Spaghetti code alert.  */
+              goto handle_on_failure_jump;
+            }
+          continue;
+
+
+        case set_number_at:
+          p += 4;
+          continue;
+
+
+        case start_memory:
+        case stop_memory:
+          p += 2;
+          continue;
+
+
+        default:
+          abort (); /* We have listed all the cases.  */
+        } /* switch *p++ */
+
+      /* Getting here means we have found the possible starting
+         characters for one path of the pattern -- and that the empty
+         string does not match.  We need not follow this path further.
+         Instead, look at the next alternative (remembered on the
+         stack), or quit if no more.  The test at the top of the loop
+         does these things.  */
+      path_can_be_null = false;
+      p = pend;
+    } /* while p */
+
+  /* Set `can_be_null' for the last path (also the first path, if the
+     pattern is empty).  */
+  bufp->can_be_null |= path_can_be_null;
+  return 0;
+} /* re_compile_fastmap */
+
+/* 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.  */
+
+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, *ends;
+{
+  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;
+    }
+}
+
+/* Searching routines.  */
+
+/* Like re_search_2, below, but only one string is specified, and
+   doesn't let you say where to stop matching. */
+
+int
+re_search (bufp, string, size, startpos, range, regs)
+     struct re_pattern_buffer *bufp;
+     const char *string;
+     int size, startpos, range;
+     struct re_registers *regs;
+{
+  return re_search_2 (bufp, NULL, 0, string, size, startpos, range,
+                      regs, size);
+}
+
+
+/* Using the compiled pattern in BUFP->buffer, first tries to match the
+   virtual concatenation of STRING1 and STRING2, starting first at index
+   STARTPOS, then at STARTPOS + 1, and so on.
+
+   STRING1 and STRING2 have length SIZE1 and SIZE2, respectively.
+
+   RANGE is how far to scan while trying to match.  RANGE = 0 means try
+   only at STARTPOS; in general, the last start tried is STARTPOS +
+   RANGE.
+
+   In REGS, return the indices of the virtual concatenation of STRING1
+   and STRING2 that matched the entire BUFP->buffer and its contained
+   subexpressions.
+
+   Do not consider matching one past the index STOP in the virtual
+   concatenation of STRING1 and STRING2.
+
+   We return either the position in the strings at which the match was
+   found, -1 if no match, or -2 if error (such as failure
+   stack overflow).  */
+
+int
+re_search_2 (bufp, string1, size1, string2, size2, startpos, range, regs, stop)
+     struct re_pattern_buffer *bufp;
+     const char *string1, *string2;
+     int size1, size2;
+     int startpos;
+     int range;
+     struct re_registers *regs;
+     int stop;
+{
+  int val;
+  register char *fastmap = bufp->fastmap;
+  register char *translate = bufp->translate;
+  int total_size = size1 + size2;
+  int endpos = startpos + range;
+
+  /* Check for out-of-range STARTPOS.  */
+  if (startpos < 0 || startpos > total_size)
+    return -1;
+
+  /* Fix up RANGE if it might eventually take us outside
+     the virtual concatenation of STRING1 and STRING2.  */
+  if (endpos < -1)
+    range = -1 - startpos;
+  else if (endpos > total_size)
+    range = total_size - startpos;
+
+  /* If the search isn't to be a backwards one, don't waste time in a
+     search for a pattern that must be anchored.  */
+  if (bufp->used > 0 && (re_opcode_t) bufp->buffer[0] == begbuf && range > 0)
+    {
+      if (startpos > 0)
+        return -1;
+      else
+        range = 1;
+    }
+
+  /* Update the fastmap now if not correct already.  */
+  if (fastmap && !bufp->fastmap_accurate)
+    if (re_compile_fastmap (bufp) == -2)
+      return -2;
+
+  /* Loop through the string, looking for a place to start matching.  */
+  for (;;)
+    {
+      /* If a fastmap is supplied, skip quickly over characters that
+         cannot be the start of a match.  If the pattern can match the
+         null string, however, we don't need to skip characters; we want
+         the first null string.  */
+      if (fastmap && startpos < total_size && !bufp->can_be_null)
+        {
+          if (range > 0)        /* Searching forwards.  */
+            {
+              register const char *d;
+              register int lim = 0;
+              int irange = range;
+
+              if (startpos < size1 && startpos + range >= size1)
+                lim = range - (size1 - startpos);
+
+              d = (startpos >= size1 ? string2 - size1 : string1) + startpos;
+
+              /* Written out as an if-else to avoid testing `translate'
+                 inside the loop.  */
+              if (translate)
+                while (range > lim
+                       && !fastmap[(unsigned char)
+                                   translate[(unsigned char) *d++]])
+                  range--;
+              else
+                while (range > lim && !fastmap[(unsigned char) *d++])
+                  range--;
+
+              startpos += irange - range;
+            }
+          else                          /* Searching backwards.  */
+            {
+              register char c = (size1 == 0 || startpos >= size1
+                                 ? string2[startpos - size1]
+                                 : string1[startpos]);
+
+              if (!fastmap[(unsigned char) TRANSLATE (c)])
+                goto advance;
+            }
+        }
+
+      /* If can't match the null string, and that's all we have left, fail.  */
+      if (range >= 0 && startpos == total_size && fastmap
+          && !bufp->can_be_null)
+        return -1;
+
+      val = re_match_2 (bufp, string1, size1, string2, size2,
+                        startpos, regs, stop);
+      if (val >= 0)
+        return startpos;
+
+      if (val == -2)
+        return -2;
+
+    advance:
+      if (!range)
+        break;
+      else if (range > 0)
+        {
+          range--;
+          startpos++;
+        }
+      else
+        {
+          range++;
+          startpos--;
+        }
+    }
+  return -1;
+} /* re_search_2 */
+
+/* Declarations and macros for re_match_2.  */
+
+static int bcmp_translate ();
+static boolean alt_match_null_string_p (),
+               common_op_match_null_string_p (),
+               group_match_null_string_p ();
+
+/* Structure for per-register (a.k.a. per-group) information.
+   This must not be longer than one word, because we push this value
+   onto the failure stack.  Other register information, such as the
+   starting and ending positions (which are addresses), and the list of
+   inner groups (which is a bits list) are maintained in separate
+   variables.
+
+   We are making a (strictly speaking) nonportable assumption here: that
+   the compiler will pack our bit fields into something that fits into
+   the type of `word', i.e., is something that fits into one item on the
+   failure stack.  */
+typedef union
+{
+  fail_stack_elt_t word;
+  struct
+  {
+      /* This field is one if this group can match the empty string,
+         zero if not.  If not yet determined,  `MATCH_NULL_UNSET_VALUE'.  */
+#define MATCH_NULL_UNSET_VALUE 3
+    unsigned match_null_string_p : 2;
+    unsigned is_active : 1;
+    unsigned matched_something : 1;
+    unsigned ever_matched_something : 1;
+  } bits;
+} register_info_type;
+
+#define REG_MATCH_NULL_STRING_P(R)  ((R).bits.match_null_string_p)
+#define IS_ACTIVE(R)  ((R).bits.is_active)
+#define MATCHED_SOMETHING(R)  ((R).bits.matched_something)
+#define EVER_MATCHED_SOMETHING(R)  ((R).bits.ever_matched_something)
+
+
+/* Call this when have matched a real character; it sets `matched' flags
+   for the subexpressions which we are currently inside.  Also records
+   that those subexprs have matched.  */
+#define SET_REGS_MATCHED()                                              \
+  do                                                                    \
+    {                                                                   \
+      unsigned r;                                                       \
+      for (r = lowest_active_reg; r <= highest_active_reg; r++)         \
+        {                                                               \
+          MATCHED_SOMETHING (reg_info[r])                               \
+            = EVER_MATCHED_SOMETHING (reg_info[r])                      \
+            = 1;                                                        \
+        }                                                               \
+    }                                                                   \
+  while (0)
+
+
+/* This converts PTR, a pointer into one of the search strings `string1'
+   and `string2' into an offset from the beginning of that string.  */
+#define POINTER_TO_OFFSET(ptr)                                          \
+  (FIRST_STRING_P (ptr) ? (ptr) - string1 : (ptr) - string2 + size1)
+
+/* Registers are set to a sentinel when they haven't yet matched.  */
+#define REG_UNSET_VALUE ((char *) -1)
+#define REG_UNSET(e) ((e) == REG_UNSET_VALUE)
+
+
+/* Macros for dealing with the split strings in re_match_2.  */
+
+#define MATCHING_IN_FIRST_STRING  (dend == end_match_1)
+
+/* Call before fetching a character with *d.  This switches over to
+   string2 if necessary.  */
+#define PREFETCH()                                                      \
+  while (d == dend)                                                     \
+    {                                                                   \
+      /* End of string2 => fail.  */                                    \
+      if (dend == end_match_2)                                          \
+        goto fail;                                                      \
+      /* End of string1 => advance to string2.  */                      \
+      d = string2;                                                      \
+      dend = end_match_2;                                               \
+    }
+
+
+/* Test if at very beginning or at very end of the virtual concatenation
+   of `string1' and `string2'.  If only one string, it's `string2'.  */
+#define AT_STRINGS_BEG(d) ((d) == (size1 ? string1 : string2) || !size2)
+#define AT_STRINGS_END(d) ((d) == end2)
+
+
+/* Test if D points to a character which is word-constituent.  We have
+   two special cases to check for: if past the end of string1, look at
+   the first character in string2; and if before the beginning of
+   string2, look at the last character in string1.  */
+#define WORDCHAR_P(d)                                                   \
+  (SYNTAX ((d) == end1 ? *string2                                       \
+           : (d) == string2 - 1 ? *(end1 - 1) : *(d))                   \
+   == Sword)
+
+/* Test if the character before D and the one at D differ with respect
+   to being word-constituent.  */
+#define AT_WORD_BOUNDARY(d)                                             \
+  (AT_STRINGS_BEG (d) || AT_STRINGS_END (d)                             \
+   || WORDCHAR_P (d - 1) != WORDCHAR_P (d))
+
+
+/* Free everything we malloc.  */
+#ifdef REGEX_MALLOC
+#define FREE_VAR(var) if (var) free (var); var = NULL
+#define FREE_VARIABLES()                                                \
+  do {                                                                  \
+    FREE_VAR (fail_stack.stack);                                        \
+    FREE_VAR (regstart);                                                \
+    FREE_VAR (regend);                                                  \
+    FREE_VAR (old_regstart);                                            \
+    FREE_VAR (old_regend);                                              \
+    FREE_VAR (best_regstart);                                           \
+    FREE_VAR (best_regend);                                             \
+    FREE_VAR (reg_info);                                                \
+    FREE_VAR (reg_dummy);                                               \
+    FREE_VAR (reg_info_dummy);                                          \
+  } while (0)
+#else /* not REGEX_MALLOC */
+/* Some MIPS systems (at least) want this to free alloca'd storage.  */
+#define FREE_VARIABLES() alloca (0)
+#endif /* not REGEX_MALLOC */
+
+
+/* These values must meet several constraints.  They must not be valid
+   register values; since we have a limit of 255 registers (because
+   we use only one byte in the pattern for the register number), we can
+   use numbers larger than 255.  They must differ by 1, because of
+   NUM_FAILURE_ITEMS above.  And the value for the lowest register must
+   be larger than the value for the highest register, so we do not try
+   to actually save any registers when none are active.  */
+#define NO_HIGHEST_ACTIVE_REG (1 << BYTEWIDTH)
+#define NO_LOWEST_ACTIVE_REG (NO_HIGHEST_ACTIVE_REG + 1)
+
+/* Matching routines.  */
+
+#ifndef emacs   /* Emacs never uses this.  */
+/* re_match is like re_match_2 except it takes only a single string.  */
+
+int
+re_match (bufp, string, size, pos, regs)
+     struct re_pattern_buffer *bufp;
+     const char *string;
+     int size, pos;
+     struct re_registers *regs;
+ {
+  return re_match_2 (bufp, NULL, 0, string, size, pos, regs, size);
+}
+#endif /* not emacs */
+
+
+/* re_match_2 matches the compiled pattern in BUFP against the
+   the (virtual) concatenation of STRING1 and STRING2 (of length SIZE1
+   and SIZE2, respectively).  We start matching at POS, and stop
+   matching at STOP.
+
+   If REGS is non-null and the `no_sub' field of BUFP is nonzero, we
+   store offsets for the substring each group matched in REGS.  See the
+   documentation for exactly how many groups we fill.
+
+   We return -1 if no match, -2 if an internal error (such as the
+   failure stack overflowing).  Otherwise, we return the length of the
+   matched substring.  */
+
+int
+re_match_2 (bufp, string1, size1, string2, size2, pos, regs, stop)
+     struct re_pattern_buffer *bufp;
+     const char *string1, *string2;
+     int size1, size2;
+     int pos;
+     struct re_registers *regs;
+     int stop;
+{
+  /* General temporaries.  */
+  int mcnt;
+  unsigned char *p1;
+
+  /* Just past the end of the corresponding string.  */
+  const char *end1, *end2;
+
+  /* Pointers into string1 and string2, just past the last characters in
+     each to consider matching.  */
+  const char *end_match_1, *end_match_2;
+
+  /* Where we are in the data, and the end of the current string.  */
+  const char *d, *dend;
+
+  /* Where we are in the pattern, and the end of the pattern.  */
+  unsigned char *p = bufp->buffer;
+  register unsigned char *pend = p + bufp->used;
+
+  /* We use this to map every character in the string.  */
+  char *translate = bufp->translate;
+
+  /* Failure point stack.  Each place that can handle a failure further
+     down the line pushes a failure point on this stack.  It consists of
+     restart, regend, and reg_info for all registers corresponding to
+     the subexpressions we're currently inside, plus the number of such
+     registers, and, finally, two char *'s.  The first char * is where
+     to resume scanning the pattern; the second one is where to resume
+     scanning the strings.  If the latter is zero, the failure point is
+     a ``dummy''; if a failure happens and the failure point is a dummy,
+     it gets discarded and the next next one is tried.  */
+  fail_stack_type fail_stack;
+#ifdef DEBUG
+  static unsigned failure_id = 0;
+  unsigned nfailure_points_pushed = 0, nfailure_points_popped = 0;
+#endif
+
+  /* We fill all the registers internally, independent of what we
+     return, for use in backreferences.  The number here includes
+     an element for register zero.  */
+  unsigned num_regs = bufp->re_nsub + 1;
+
+  /* The currently active registers.  */
+  unsigned lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+  unsigned highest_active_reg = NO_HIGHEST_ACTIVE_REG;
+
+  /* Information on the contents of registers. These are pointers into
+     the input strings; they record just what was matched (on this
+     attempt) by a subexpression part of the pattern, that is, the
+     regnum-th regstart pointer points to where in the pattern we began
+     matching and the regnum-th regend points to right after where we
+     stopped matching the regnum-th subexpression.  (The zeroth register
+     keeps track of what the whole pattern matches.)  */
+  const char **regstart = NULL, **regend = NULL;
+
+  /* If a group that's operated upon by a repetition operator fails to
+     match anything, then the register for its start will need to be
+     restored because it will have been set to wherever in the string we
+     are when we last see its open-group operator.  Similarly for a
+     register's end.  */
+  const char **old_regstart = NULL, **old_regend = NULL;
+
+  /* The is_active field of reg_info helps us keep track of which (possibly
+     nested) subexpressions we are currently in. The matched_something
+     field of reg_info[reg_num] helps us tell whether or not we have
+     matched any of the pattern so far this time through the reg_num-th
+     subexpression.  These two fields get reset each time through any
+     loop their register is in.  */
+  register_info_type *reg_info = NULL;
+
+  /* The following record the register info as found in the above
+     variables when we find a match better than any we've seen before.
+     This happens as we backtrack through the failure points, which in
+     turn happens only if we have not yet matched the entire string. */
+  unsigned best_regs_set = false;
+  const char **best_regstart = NULL, **best_regend = NULL;
+
+  /* Logically, this is `best_regend[0]'.  But we don't want to have to
+     allocate space for that if we're not allocating space for anything
+     else (see below).  Also, we never need info about register 0 for
+     any of the other register vectors, and it seems rather a kludge to
+     treat `best_regend' differently than the rest.  So we keep track of
+     the end of the best match so far in a separate variable.  We
+     initialize this to NULL so that when we backtrack the first time
+     and need to test it, it's not garbage.  */
+  const char *match_end = NULL;
+
+  /* Used when we pop values we don't care about.  */
+  const char **reg_dummy = NULL;
+  register_info_type *reg_info_dummy = NULL;
+
+#ifdef DEBUG
+  /* Counts the total number of registers pushed.  */
+  unsigned num_regs_pushed = 0;
+#endif
+
+  DEBUG_PRINT1 ("\n\nEntering re_match_2.\n");
+
+  INIT_FAIL_STACK ();
+
+  /* Do not bother to initialize all the register variables if there are
+     no groups in the pattern, as it takes a fair amount of time.  If
+     there are groups, we include space for register 0 (the whole
+     pattern), even though we never use it, since it simplifies the
+     array indexing.  We should fix this.  */
+  if (bufp->re_nsub)
+    {
+      regstart = REGEX_TALLOC (num_regs, const char *);
+      regend = REGEX_TALLOC (num_regs, const char *);
+      old_regstart = REGEX_TALLOC (num_regs, const char *);
+      old_regend = REGEX_TALLOC (num_regs, const char *);
+      best_regstart = REGEX_TALLOC (num_regs, const char *);
+      best_regend = REGEX_TALLOC (num_regs, const char *);
+      reg_info = REGEX_TALLOC (num_regs, register_info_type);
+      reg_dummy = REGEX_TALLOC (num_regs, const char *);
+      reg_info_dummy = REGEX_TALLOC (num_regs, register_info_type);
+
+      if (!(regstart && regend && old_regstart && old_regend && reg_info
+            && best_regstart && best_regend && reg_dummy && reg_info_dummy))
+        {
+          FREE_VARIABLES ();
+          return -2;
+        }
+    }
+#ifdef REGEX_MALLOC
+  else
+    {
+      /* We must initialize all our variables to NULL, so that
+         `FREE_VARIABLES' doesn't try to free them.  */
+      regstart = regend = old_regstart = old_regend = best_regstart
+        = best_regend = reg_dummy = NULL;
+      reg_info = reg_info_dummy = (register_info_type *) NULL;
+    }
+#endif /* REGEX_MALLOC */
+
+  /* The starting position is bogus.  */
+  if (pos < 0 || pos > size1 + size2)
+    {
+      FREE_VARIABLES ();
+      return -1;
+    }
+
+  /* Initialize subexpression text positions to -1 to mark ones that no
+     start_memory/stop_memory has been seen for. Also initialize the
+     register information struct.  */
+  for (mcnt = 1; mcnt < num_regs; mcnt++)
+    {
+      regstart[mcnt] = regend[mcnt]
+        = old_regstart[mcnt] = old_regend[mcnt] = REG_UNSET_VALUE;
+
+      REG_MATCH_NULL_STRING_P (reg_info[mcnt]) = MATCH_NULL_UNSET_VALUE;
+      IS_ACTIVE (reg_info[mcnt]) = 0;
+      MATCHED_SOMETHING (reg_info[mcnt]) = 0;
+      EVER_MATCHED_SOMETHING (reg_info[mcnt]) = 0;
+    }
+
+  /* We move `string1' into `string2' if the latter's empty -- but not if
+     `string1' is null.  */
+  if (size2 == 0 && string1 != NULL)
+    {
+      string2 = string1;
+      size2 = size1;
+      string1 = 0;
+      size1 = 0;
+    }
+  end1 = string1 + size1;
+  end2 = string2 + size2;
+
+  /* Compute where to stop matching, within the two strings.  */
+  if (stop <= size1)
+    {
+      end_match_1 = string1 + stop;
+      end_match_2 = string2;
+    }
+  else
+    {
+      end_match_1 = end1;
+      end_match_2 = string2 + stop - size1;
+    }
+
+  /* `p' scans through the pattern as `d' scans through the data.
+     `dend' is the end of the input string that `d' points within.  `d'
+     is advanced into the following input string whenever necessary, but
+     this happens before fetching; therefore, at the beginning of the
+     loop, `d' can be pointing at the end of a string, but it cannot
+     equal `string2'.  */
+  if (size1 > 0 && pos <= size1)
+    {
+      d = string1 + pos;
+      dend = end_match_1;
+    }
+  else
+    {
+      d = string2 + pos - size1;
+      dend = end_match_2;
+    }
+
+  DEBUG_PRINT1 ("The compiled pattern is: ");
+  DEBUG_PRINT_COMPILED_PATTERN (bufp, p, pend);
+  DEBUG_PRINT1 ("The string to match is: `");
+  DEBUG_PRINT_DOUBLE_STRING (d, string1, size1, string2, size2);
+  DEBUG_PRINT1 ("'\n");
+
+  /* This loops over pattern commands.  It exits by returning from the
+     function if the match is complete, or it drops through if the match
+     fails at this starting point in the input data.  */
+  for (;;)
+    {
+      DEBUG_PRINT2 ("\n0x%x: ", p);
+
+      if (p == pend)
+        { /* End of pattern means we might have succeeded.  */
+          DEBUG_PRINT1 ("end of pattern ... ");
+
+          /* If we haven't matched the entire string, and we want the
+             longest match, try backtracking.  */
+          if (d != end_match_2)
+            {
+              DEBUG_PRINT1 ("backtracking.\n");
+
+              if (!FAIL_STACK_EMPTY ())
+                { /* More failure points to try.  */
+                  boolean same_str_p = (FIRST_STRING_P (match_end)
+                                        == MATCHING_IN_FIRST_STRING);
+
+                  /* If exceeds best match so far, save it.  */
+                  if (!best_regs_set
+                      || (same_str_p && d > match_end)
+                      || (!same_str_p && !MATCHING_IN_FIRST_STRING))
+                    {
+                      best_regs_set = true;
+                      match_end = d;
+
+                      DEBUG_PRINT1 ("\nSAVING match as best so far.\n");
+
+                      for (mcnt = 1; mcnt < num_regs; mcnt++)
+                        {
+                          best_regstart[mcnt] = regstart[mcnt];
+                          best_regend[mcnt] = regend[mcnt];
+                        }
+                    }
+                  goto fail;
+                }
+
+              /* If no failure points, don't restore garbage.  */
+              else if (best_regs_set)
+                {
+                restore_best_regs:
+                  /* Restore best match.  It may happen that `dend ==
+                     end_match_1' while the restored d is in string2.
+                     For example, the pattern `x.*y.*z' against the
+                     strings `x-' and `y-z-', if the two strings are
+                     not consecutive in memory.  */
+                  DEBUG_PRINT1 ("Restoring best registers.\n");
+
+                  d = match_end;
+                  dend = ((d >= string1 && d <= end1)
+                           ? end_match_1 : end_match_2);
+
+                  for (mcnt = 1; mcnt < num_regs; mcnt++)
+                    {
+                      regstart[mcnt] = best_regstart[mcnt];
+                      regend[mcnt] = best_regend[mcnt];
+                    }
+                }
+            } /* d != end_match_2 */
+
+          DEBUG_PRINT1 ("Accepting match.\n");
+
+          /* If caller wants register contents data back, do it.  */
+          if (regs && !bufp->no_sub)
+            {
+              /* Have the register data arrays been allocated?  */
+              if (bufp->regs_allocated == REGS_UNALLOCATED)
+                { /* No.  So allocate them with malloc.  We need one
+                     extra element beyond `num_regs' for the `-1' marker
+                     GNU code uses.  */
+                  regs->num_regs = MAX (RE_NREGS, num_regs + 1);
+                  regs->start = TALLOC (regs->num_regs, regoff_t);
+                  regs->end = TALLOC (regs->num_regs, regoff_t);
+                  if (regs->start == NULL || regs->end == NULL)
+                    return -2;
+                  bufp->regs_allocated = REGS_REALLOCATE;
+                }
+              else if (bufp->regs_allocated == REGS_REALLOCATE)
+                { /* Yes.  If we need more elements than were already
+                     allocated, reallocate them.  If we need fewer, just
+                     leave it alone.  */
+                  if (regs->num_regs < num_regs + 1)
+                    {
+                      regs->num_regs = num_regs + 1;
+                      RETALLOC (regs->start, regs->num_regs, regoff_t);
+                      RETALLOC (regs->end, regs->num_regs, regoff_t);
+                      if (regs->start == NULL || regs->end == NULL)
+                        return -2;
+                    }
+                }
+              else
+                assert (bufp->regs_allocated == REGS_FIXED);
+
+              /* Convert the pointer data in `regstart' and `regend' to
+                 indices.  Register zero has to be set differently,
+                 since we haven't kept track of any info for it.  */
+              if (regs->num_regs > 0)
+                {
+                  regs->start[0] = pos;
+                  regs->end[0] = (MATCHING_IN_FIRST_STRING ? d - string1
+                                  : d - string2 + size1);
+                }
+
+              /* Go through the first `min (num_regs, regs->num_regs)'
+                 registers, since that is all we initialized.  */
+              for (mcnt = 1; mcnt < MIN (num_regs, regs->num_regs); mcnt++)
+                {
+                  if (REG_UNSET (regstart[mcnt]) || REG_UNSET (regend[mcnt]))
+                    regs->start[mcnt] = regs->end[mcnt] = -1;
+                  else
+                    {
+                      regs->start[mcnt] = POINTER_TO_OFFSET (regstart[mcnt]);
+                      regs->end[mcnt] = POINTER_TO_OFFSET (regend[mcnt]);
+                    }
+                }
+
+              /* If the regs structure we return has more elements than
+                 were in the pattern, set the extra elements to -1.  If
+                 we (re)allocated the registers, this is the case,
+                 because we always allocate enough to have at least one
+                 -1 at the end.  */
+              for (mcnt = num_regs; mcnt < regs->num_regs; mcnt++)
+                regs->start[mcnt] = regs->end[mcnt] = -1;
+            } /* regs && !bufp->no_sub */
+
+          FREE_VARIABLES ();
+          DEBUG_PRINT4 ("%u failure points pushed, %u popped (%u remain).\n",
+                        nfailure_points_pushed, nfailure_points_popped,
+                        nfailure_points_pushed - nfailure_points_popped);
+          DEBUG_PRINT2 ("%u registers pushed.\n", num_regs_pushed);
+
+          mcnt = d - pos - (MATCHING_IN_FIRST_STRING
+                            ? string1
+                            : string2 - size1);
+
+          DEBUG_PRINT2 ("Returning %d from re_match_2.\n", mcnt);
+
+          return mcnt;
+        }
+
+      /* Otherwise match next pattern command.  */
+#ifdef SWITCH_ENUM_BUG
+      switch ((int) ((re_opcode_t) *p++))
+#else
+      switch ((re_opcode_t) *p++)
+#endif
+        {
+        /* Ignore these.  Used to ignore the n of succeed_n's which
+           currently have n == 0.  */
+        case no_op:
+          DEBUG_PRINT1 ("EXECUTING no_op.\n");
+          break;
+
+
+        /* Match the next n pattern characters exactly.  The following
+           byte in the pattern defines n, and the n bytes after that
+           are the characters to match.  */
+        case exactn:
+          mcnt = *p++;
+          DEBUG_PRINT2 ("EXECUTING exactn %d.\n", mcnt);
+
+          /* This is written out as an if-else so we don't waste time
+             testing `translate' inside the loop.  */
+          if (translate)
+            {
+              do
+                {
+                  PREFETCH ();
+                  if (translate[(unsigned char) *d++] != (char) *p++)
+                    goto fail;
+                }
+              while (--mcnt);
+            }
+          else
+            {
+              do
+                {
+                  PREFETCH ();
+                  if (*d++ != (char) *p++) goto fail;
+                }
+              while (--mcnt);
+            }
+          SET_REGS_MATCHED ();
+          break;
+
+
+        /* Match any character except possibly a newline or a null.  */
+        case anychar:
+          DEBUG_PRINT1 ("EXECUTING anychar.\n");
+
+          PREFETCH ();
+
+          if ((!(bufp->syntax & RE_DOT_NEWLINE) && TRANSLATE (*d) == '\n')
+              || (bufp->syntax & RE_DOT_NOT_NULL && TRANSLATE (*d) == '\000'))
+            goto fail;
+
+          SET_REGS_MATCHED ();
+          DEBUG_PRINT2 ("  Matched `%d'.\n", *d);
+          d++;
+          break;
+
+
+        case charset:
+        case charset_not:
+          {
+            register unsigned char c;
+            boolean not = (re_opcode_t) *(p - 1) == charset_not;
+
+            DEBUG_PRINT2 ("EXECUTING charset%s.\n", not ? "_not" : "");
+
+            PREFETCH ();
+            c = TRANSLATE (*d); /* The character to match.  */
+
+            /* Cast to `unsigned' instead of `unsigned char' in case the
+               bit list is a full 32 bytes long.  */
+            if (c < (unsigned) (*p * BYTEWIDTH)
+                && p[1 + c / BYTEWIDTH] & (1 << (c % BYTEWIDTH)))
+              not = !not;
+
+            p += 1 + *p;
+
+            if (!not) goto fail;
+
+            SET_REGS_MATCHED ();
+            d++;
+            break;
+          }
+
+
+        /* The beginning of a group is represented by start_memory.
+           The arguments are the register number in the next byte, and the
+           number of groups inner to this one in the next.  The text
+           matched within the group is recorded (in the internal
+           registers data structure) under the register number.  */
+        case start_memory:
+          DEBUG_PRINT3 ("EXECUTING start_memory %d (%d):\n", *p, p[1]);
+
+          /* Find out if this group can match the empty string.  */
+          p1 = p;               /* To send to group_match_null_string_p.  */
+
+          if (REG_MATCH_NULL_STRING_P (reg_info[*p]) == MATCH_NULL_UNSET_VALUE)
+            REG_MATCH_NULL_STRING_P (reg_info[*p])
+              = group_match_null_string_p (&p1, pend, reg_info);
+
+          /* Save the position in the string where we were the last time
+             we were at this open-group operator in case the group is
+             operated upon by a repetition operator, e.g., with `(a*)*b'
+             against `ab'; then we want to ignore where we are now in
+             the string in case this attempt to match fails.  */
+          old_regstart[*p] = REG_MATCH_NULL_STRING_P (reg_info[*p])
+                             ? REG_UNSET (regstart[*p]) ? d : regstart[*p]
+                             : regstart[*p];
+          DEBUG_PRINT2 ("  old_regstart: %d\n",
+                         POINTER_TO_OFFSET (old_regstart[*p]));
+
+          regstart[*p] = d;
+          DEBUG_PRINT2 ("  regstart: %d\n", POINTER_TO_OFFSET (regstart[*p]));
+
+          IS_ACTIVE (reg_info[*p]) = 1;
+          MATCHED_SOMETHING (reg_info[*p]) = 0;
+
+          /* This is the new highest active register.  */
+          highest_active_reg = *p;
+
+          /* If nothing was active before, this is the new lowest active
+             register.  */
+          if (lowest_active_reg == NO_LOWEST_ACTIVE_REG)
+            lowest_active_reg = *p;
+
+          /* Move past the register number and inner group count.  */
+          p += 2;
+          break;
+
+
+        /* The stop_memory opcode represents the end of a group.  Its
+           arguments are the same as start_memory's: the register
+           number, and the number of inner groups.  */
+        case stop_memory:
+          DEBUG_PRINT3 ("EXECUTING stop_memory %d (%d):\n", *p, p[1]);
+
+          /* We need to save the string position the last time we were at
+             this close-group operator in case the group is operated
+             upon by a repetition operator, e.g., with `((a*)*(b*)*)*'
+             against `aba'; then we want to ignore where we are now in
+             the string in case this attempt to match fails.  */
+          old_regend[*p] = REG_MATCH_NULL_STRING_P (reg_info[*p])
+                           ? REG_UNSET (regend[*p]) ? d : regend[*p]
+                           : regend[*p];
+          DEBUG_PRINT2 ("      old_regend: %d\n",
+                         POINTER_TO_OFFSET (old_regend[*p]));
+
+          regend[*p] = d;
+          DEBUG_PRINT2 ("      regend: %d\n", POINTER_TO_OFFSET (regend[*p]));
+
+          /* This register isn't active anymore.  */
+          IS_ACTIVE (reg_info[*p]) = 0;
+
+          /* If this was the only register active, nothing is active
+             anymore.  */
+          if (lowest_active_reg == highest_active_reg)
+            {
+              lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+              highest_active_reg = NO_HIGHEST_ACTIVE_REG;
+            }
+          else
+            { /* We must scan for the new highest active register, since
+                 it isn't necessarily one less than now: consider
+                 (a(b)c(d(e)f)g).  When group 3 ends, after the f), the
+                 new highest active register is 1.  */
+              unsigned char r = *p - 1;
+              while (r > 0 && !IS_ACTIVE (reg_info[r]))
+                r--;
+
+              /* If we end up at register zero, that means that we saved
+                 the registers as the result of an `on_failure_jump', not
+                 a `start_memory', and we jumped to past the innermost
+                 `stop_memory'.  For example, in ((.)*) we save
+                 registers 1 and 2 as a result of the *, but when we pop
+                 back to the second ), we are at the stop_memory 1.
+                 Thus, nothing is active.  */
+              if (r == 0)
+                {
+                  lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+                  highest_active_reg = NO_HIGHEST_ACTIVE_REG;
+                }
+              else
+                highest_active_reg = r;
+            }
+
+          /* If just failed to match something this time around with a
+             group that's operated on by a repetition operator, try to
+             force exit from the ``loop'', and restore the register
+             information for this group that we had before trying this
+             last match.  */
+          if ((!MATCHED_SOMETHING (reg_info[*p])
+               || (re_opcode_t) p[-3] == start_memory)
+              && (p + 2) < pend)
+            {
+              boolean is_a_jump_n = false;
+
+              p1 = p + 2;
+              mcnt = 0;
+              switch ((re_opcode_t) *p1++)
+                {
+                  case jump_n:
+                    is_a_jump_n = true;
+                  case pop_failure_jump:
+                  case maybe_pop_jump:
+                  case jump:
+                  case dummy_failure_jump:
+                    EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+                    if (is_a_jump_n)
+                      p1 += 2;
+                    break;
+
+                  default:
+                    /* do nothing */ ;
+                }
+              p1 += mcnt;
+
+              /* If the next operation is a jump backwards in the pattern
+                 to an on_failure_jump right before the start_memory
+                 corresponding to this stop_memory, exit from the loop
+                 by forcing a failure after pushing on the stack the
+                 on_failure_jump's jump in the pattern, and d.  */
+              if (mcnt < 0 && (re_opcode_t) *p1 == on_failure_jump
+                  && (re_opcode_t) p1[3] == start_memory && p1[4] == *p)
+                {
+                  /* If this group ever matched anything, then restore
+                     what its registers were before trying this last
+                     failed match, e.g., with `(a*)*b' against `ab' for
+                     regstart[1], and, e.g., with `((a*)*(b*)*)*'
+                     against `aba' for regend[3].
+
+                     Also restore the registers for inner groups for,
+                     e.g., `((a*)(b*))*' against `aba' (register 3 would
+                     otherwise get trashed).  */
+
+                  if (EVER_MATCHED_SOMETHING (reg_info[*p]))
+                    {
+                      unsigned r;
+
+                      EVER_MATCHED_SOMETHING (reg_info[*p]) = 0;
+
+                      /* Restore this and inner groups' (if any) registers.  */
+                      for (r = *p; r < *p + *(p + 1); r++)
+                        {
+                          regstart[r] = old_regstart[r];
+
+                          /* xx why this test?  */
+                          if ((int) old_regend[r] >= (int) regstart[r])
+                            regend[r] = old_regend[r];
+                        }
+                    }
+                  p1++;
+                  EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+                  PUSH_FAILURE_POINT (p1 + mcnt, d, -2);
+
+                  goto fail;
+                }
+            }
+
+          /* Move past the register number and the inner group count.  */
+          p += 2;
+          break;
+
+
+        /* \<digit> has been turned into a `duplicate' command which is
+           followed by the numeric value of <digit> as the register number.  */
+        case duplicate:
+          {
+            register const char *d2, *dend2;
+            int regno = *p++;   /* Get which register to match against.  */
+            DEBUG_PRINT2 ("EXECUTING duplicate %d.\n", regno);
+
+            /* Can't back reference a group which we've never matched.  */
+            if (REG_UNSET (regstart[regno]) || REG_UNSET (regend[regno]))
+              goto fail;
+
+            /* Where in input to try to start matching.  */
+            d2 = regstart[regno];
+
+            /* Where to stop matching; if both the place to start and
+               the place to stop matching are in the same string, then
+               set to the place to stop, otherwise, for now have to use
+               the end of the first string.  */
+
+            dend2 = ((FIRST_STRING_P (regstart[regno])
+                      == FIRST_STRING_P (regend[regno]))
+                     ? regend[regno] : end_match_1);
+            for (;;)
+              {
+                /* If necessary, advance to next segment in register
+                   contents.  */
+                while (d2 == dend2)
+                  {
+                    if (dend2 == end_match_2) break;
+                    if (dend2 == regend[regno]) break;
+
+                    /* End of string1 => advance to string2. */
+                    d2 = string2;
+                    dend2 = regend[regno];
+                  }
+                /* At end of register contents => success */
+                if (d2 == dend2) break;
+
+                /* If necessary, advance to next segment in data.  */
+                PREFETCH ();
+
+                /* How many characters left in this segment to match.  */
+                mcnt = dend - d;
+
+                /* Want how many consecutive characters we can match in
+                   one shot, so, if necessary, adjust the count.  */
+                if (mcnt > dend2 - d2)
+                  mcnt = dend2 - d2;
+
+                /* Compare that many; failure if mismatch, else move
+                   past them.  */
+                if (translate
+                    ? bcmp_translate (d, d2, mcnt, translate)
+                    : bcmp (d, d2, mcnt))
+                  goto fail;
+                d += mcnt, d2 += mcnt;
+              }
+          }
+          break;
+
+
+        /* begline matches the empty string at the beginning of the string
+           (unless `not_bol' is set in `bufp'), and, if
+           `newline_anchor' is set, after newlines.  */
+        case begline:
+          DEBUG_PRINT1 ("EXECUTING begline.\n");
+
+          if (AT_STRINGS_BEG (d))
+            {
+              if (!bufp->not_bol) break;
+            }
+          else if (d[-1] == '\n' && bufp->newline_anchor)
+            {
+              break;
+            }
+          /* In all other cases, we fail.  */
+          goto fail;
+
+
+        /* endline is the dual of begline.  */
+        case endline:
+          DEBUG_PRINT1 ("EXECUTING endline.\n");
+
+          if (AT_STRINGS_END (d))
+            {
+              if (!bufp->not_eol) break;
+            }
+
+          /* We have to ``prefetch'' the next character.  */
+          else if ((d == end1 ? *string2 : *d) == '\n'
+                   && bufp->newline_anchor)
+            {
+              break;
+            }
+          goto fail;
+
+
+        /* Match at the very beginning of the data.  */
+        case begbuf:
+          DEBUG_PRINT1 ("EXECUTING begbuf.\n");
+          if (AT_STRINGS_BEG (d))
+            break;
+          goto fail;
+
+
+        /* Match at the very end of the data.  */
+        case endbuf:
+          DEBUG_PRINT1 ("EXECUTING endbuf.\n");
+          if (AT_STRINGS_END (d))
+            break;
+          goto fail;
+
+
+        /* on_failure_keep_string_jump is used to optimize `.*\n'.  It
+           pushes NULL as the value for the string on the stack.  Then
+           `pop_failure_point' will keep the current value for the
+           string, instead of restoring it.  To see why, consider
+           matching `foo\nbar' against `.*\n'.  The .* matches the foo;
+           then the . fails against the \n.  But the next thing we want
+           to do is match the \n against the \n; if we restored the
+           string value, we would be back at the foo.
+
+           Because this is used only in specific cases, we don't need to
+           check all the things that `on_failure_jump' does, to make
+           sure the right things get saved on the stack.  Hence we don't
+           share its code.  The only reason to push anything on the
+           stack at all is that otherwise we would have to change
+           `anychar's code to do something besides goto fail in this
+           case; that seems worse than this.  */
+        case on_failure_keep_string_jump:
+          DEBUG_PRINT1 ("EXECUTING on_failure_keep_string_jump");
+
+          EXTRACT_NUMBER_AND_INCR (mcnt, p);
+          DEBUG_PRINT3 (" %d (to 0x%x):\n", mcnt, p + mcnt);
+
+          PUSH_FAILURE_POINT (p + mcnt, NULL, -2);
+          break;
+
+
+        /* Uses of on_failure_jump:
+
+           Each alternative starts with an on_failure_jump that points
+           to the beginning of the next alternative.  Each alternative
+           except the last ends with a jump that in effect jumps past
+           the rest of the alternatives.  (They really jump to the
+           ending jump of the following alternative, because tensioning
+           these jumps is a hassle.)
+
+           Repeats start with an on_failure_jump that points past both
+           the repetition text and either the following jump or
+           pop_failure_jump back to this on_failure_jump.  */
+        case on_failure_jump:
+        on_failure:
+          DEBUG_PRINT1 ("EXECUTING on_failure_jump");
+
+          EXTRACT_NUMBER_AND_INCR (mcnt, p);
+          DEBUG_PRINT3 (" %d (to 0x%x)", mcnt, p + mcnt);
+
+          /* If this on_failure_jump comes right before a group (i.e.,
+             the original * applied to a group), save the information
+             for that group and all inner ones, so that if we fail back
+             to this point, the group's information will be correct.
+             For example, in \(a*\)*\1, we need the preceding group,
+             and in \(\(a*\)b*\)\2, we need the inner group.  */
+
+          /* We can't use `p' to check ahead because we push
+             a failure point to `p + mcnt' after we do this.  */
+          p1 = p;
+
+          /* We need to skip no_op's before we look for the
+             start_memory in case this on_failure_jump is happening as
+             the result of a completed succeed_n, as in \(a\)\{1,3\}b\1
+             against aba.  */
+          while (p1 < pend && (re_opcode_t) *p1 == no_op)
+            p1++;
+
+          if (p1 < pend && (re_opcode_t) *p1 == start_memory)
+            {
+              /* We have a new highest active register now.  This will
+                 get reset at the start_memory we are about to get to,
+                 but we will have saved all the registers relevant to
+                 this repetition op, as described above.  */
+              highest_active_reg = *(p1 + 1) + *(p1 + 2);
+              if (lowest_active_reg == NO_LOWEST_ACTIVE_REG)
+                lowest_active_reg = *(p1 + 1);
+            }
+
+          DEBUG_PRINT1 (":\n");
+          PUSH_FAILURE_POINT (p + mcnt, d, -2);
+          break;
+
+
+        /* A smart repeat ends with `maybe_pop_jump'.
+           We change it to either `pop_failure_jump' or `jump'.  */
+        case maybe_pop_jump:
+          EXTRACT_NUMBER_AND_INCR (mcnt, p);
+          DEBUG_PRINT2 ("EXECUTING maybe_pop_jump %d.\n", mcnt);
+          {
+            register unsigned char *p2 = p;
+
+            /* Compare the beginning of the repeat with what in the
+               pattern follows its end. If we can establish that there
+               is nothing that they would both match, i.e., that we
+               would have to backtrack because of (as in, e.g., `a*a')
+               then we can change to pop_failure_jump, because we'll
+               never have to backtrack.
+
+               This is not true in the case of alternatives: in
+               `(a|ab)*' we do need to backtrack to the `ab' alternative
+               (e.g., if the string was `ab').  But instead of trying to
+               detect that here, the alternative has put on a dummy
+               failure point which is what we will end up popping.  */
+
+            /* Skip over open/close-group commands.  */
+            while (p2 + 2 < pend
+                   && ((re_opcode_t) *p2 == stop_memory
+                       || (re_opcode_t) *p2 == start_memory))
+              p2 += 3;                  /* Skip over args, too.  */
+
+            /* If we're at the end of the pattern, we can change.  */
+            if (p2 == pend)
+              {
+                /* Consider what happens when matching ":\(.*\)"
+                   against ":/".  I don't really understand this code
+                   yet.  */
+                p[-3] = (unsigned char) pop_failure_jump;
+                DEBUG_PRINT1
+                  ("  End of pattern: change to `pop_failure_jump'.\n");
+              }
+
+            else if ((re_opcode_t) *p2 == exactn
+                     || (bufp->newline_anchor && (re_opcode_t) *p2 == endline))
+              {
+                register unsigned char c
+                  = *p2 == (unsigned char) endline ? '\n' : p2[2];
+                p1 = p + mcnt;
+
+                /* p1[0] ... p1[2] are the `on_failure_jump' corresponding
+                   to the `maybe_finalize_jump' of this case.  Examine what
+                   follows.  */
+                if ((re_opcode_t) p1[3] == exactn && p1[5] != c)
+                  {
+                    p[-3] = (unsigned char) pop_failure_jump;
+                    DEBUG_PRINT3 ("  %c != %c => pop_failure_jump.\n",
+                                  c, p1[5]);
+                  }
+
+                else if ((re_opcode_t) p1[3] == charset
+                         || (re_opcode_t) p1[3] == charset_not)
+                  {
+                    int not = (re_opcode_t) p1[3] == charset_not;
+
+                    if (c < (unsigned char) (p1[4] * BYTEWIDTH)
+                        && p1[5 + c / BYTEWIDTH] & (1 << (c % BYTEWIDTH)))
+                      not = !not;
+
+                    /* `not' is equal to 1 if c would match, which means
+                        that we can't change to pop_failure_jump.  */
+                    if (!not)
+                      {
+                        p[-3] = (unsigned char) pop_failure_jump;
+                        DEBUG_PRINT1 ("  No match => pop_failure_jump.\n");
+                      }
+                  }
+              }
+          }
+          p -= 2;               /* Point at relative address again.  */
+          if ((re_opcode_t) p[-1] != pop_failure_jump)
+            {
+              p[-1] = (unsigned char) jump;
+              DEBUG_PRINT1 ("  Match => jump.\n");
+              goto unconditional_jump;
+            }
+        /* Note fall through.  */
+
+
+        /* The end of a simple repeat has a pop_failure_jump back to
+           its matching on_failure_jump, where the latter will push a
+           failure point.  The pop_failure_jump takes off failure
+           points put on by this pop_failure_jump's matching
+           on_failure_jump; we got through the pattern to here from the
+           matching on_failure_jump, so didn't fail.  */
+        case pop_failure_jump:
+          {
+            /* We need to pass separate storage for the lowest and
+               highest registers, even though we don't care about the
+               actual values.  Otherwise, we will restore only one
+               register from the stack, since lowest will == highest in
+               `pop_failure_point'.  */
+            unsigned dummy_low_reg, dummy_high_reg;
+            unsigned char *pdummy;
+            const char *sdummy;
+
+            DEBUG_PRINT1 ("EXECUTING pop_failure_jump.\n");
+            POP_FAILURE_POINT (sdummy, pdummy,
+                               dummy_low_reg, dummy_high_reg,
+                               reg_dummy, reg_dummy, reg_info_dummy);
+          }
+          /* Note fall through.  */
+
+
+        /* Unconditionally jump (without popping any failure points).  */
+        case jump:
+        unconditional_jump:
+          EXTRACT_NUMBER_AND_INCR (mcnt, p);    /* Get the amount to jump.  */
+          DEBUG_PRINT2 ("EXECUTING jump %d ", mcnt);
+          p += mcnt;                            /* Do the jump.  */
+          DEBUG_PRINT2 ("(to 0x%x).\n", p);
+          break;
+
+
+        /* We need this opcode so we can detect where alternatives end
+           in `group_match_null_string_p' et al.  */
+        case jump_past_alt:
+          DEBUG_PRINT1 ("EXECUTING jump_past_alt.\n");
+          goto unconditional_jump;
+
+
+        /* Normally, the on_failure_jump pushes a failure point, which
+           then gets popped at pop_failure_jump.  We will end up at
+           pop_failure_jump, also, and with a pattern of, say, `a+', we
+           are skipping over the on_failure_jump, so we have to push
+           something meaningless for pop_failure_jump to pop.  */
+        case dummy_failure_jump:
+          DEBUG_PRINT1 ("EXECUTING dummy_failure_jump.\n");
+          /* It doesn't matter what we push for the string here.  What
+             the code at `fail' tests is the value for the pattern.  */
+          PUSH_FAILURE_POINT (0, 0, -2);
+          goto unconditional_jump;
+
+
+        /* At the end of an alternative, we need to push a dummy failure
+           point in case we are followed by a `pop_failure_jump', because
+           we don't want the failure point for the alternative to be
+           popped.  For example, matching `(a|ab)*' against `aab'
+           requires that we match the `ab' alternative.  */
+        case push_dummy_failure:
+          DEBUG_PRINT1 ("EXECUTING push_dummy_failure.\n");
+          /* See comments just above at `dummy_failure_jump' about the
+             two zeroes.  */
+          PUSH_FAILURE_POINT (0, 0, -2);
+          break;
+
+        /* Have to succeed matching what follows at least n times.
+           After that, handle like `on_failure_jump'.  */
+        case succeed_n:
+          EXTRACT_NUMBER (mcnt, p + 2);
+          DEBUG_PRINT2 ("EXECUTING succeed_n %d.\n", mcnt);
+
+          assert (mcnt >= 0);
+          /* Originally, this is how many times we HAVE to succeed.  */
+          if (mcnt > 0)
+            {
+               mcnt--;
+               p += 2;
+               STORE_NUMBER_AND_INCR (p, mcnt);
+               DEBUG_PRINT3 ("  Setting 0x%x to %d.\n", p, mcnt);
+            }
+          else if (mcnt == 0)
+            {
+              DEBUG_PRINT2 ("  Setting two bytes from 0x%x to no_op.\n", p+2);
+              p[2] = (unsigned char) no_op;
+              p[3] = (unsigned char) no_op;
+              goto on_failure;
+            }
+          break;
+
+        case jump_n:
+          EXTRACT_NUMBER (mcnt, p + 2);
+          DEBUG_PRINT2 ("EXECUTING jump_n %d.\n", mcnt);
+
+          /* Originally, this is how many times we CAN jump.  */
+          if (mcnt)
+            {
+               mcnt--;
+               STORE_NUMBER (p + 2, mcnt);
+               goto unconditional_jump;
+            }
+          /* If don't have to jump any more, skip over the rest of command.  */
+          else
+            p += 4;
+          break;
+
+        case set_number_at:
+          {
+            DEBUG_PRINT1 ("EXECUTING set_number_at.\n");
+
+            EXTRACT_NUMBER_AND_INCR (mcnt, p);
+            p1 = p + mcnt;
+            EXTRACT_NUMBER_AND_INCR (mcnt, p);
+            DEBUG_PRINT3 ("  Setting 0x%x to %d.\n", p1, mcnt);
+            STORE_NUMBER (p1, mcnt);
+            break;
+          }
+
+        case wordbound:
+          DEBUG_PRINT1 ("EXECUTING wordbound.\n");
+          if (AT_WORD_BOUNDARY (d))
+            break;
+          goto fail;
+
+        case notwordbound:
+          DEBUG_PRINT1 ("EXECUTING notwordbound.\n");
+          if (AT_WORD_BOUNDARY (d))
+            goto fail;
+          break;
+
+        case wordbeg:
+          DEBUG_PRINT1 ("EXECUTING wordbeg.\n");
+          if (WORDCHAR_P (d) && (AT_STRINGS_BEG (d) || !WORDCHAR_P (d - 1)))
+            break;
+          goto fail;
+
+        case wordend:
+          DEBUG_PRINT1 ("EXECUTING wordend.\n");
+          if (!AT_STRINGS_BEG (d) && WORDCHAR_P (d - 1)
+              && (!WORDCHAR_P (d) || AT_STRINGS_END (d)))
+            break;
+          goto fail;
+
+#ifdef emacs
+#ifdef emacs19
+        case before_dot:
+          DEBUG_PRINT1 ("EXECUTING before_dot.\n");
+          if (PTR_CHAR_POS ((unsigned char *) d) >= point)
+            goto fail;
+          break;
+
+        case at_dot:
+          DEBUG_PRINT1 ("EXECUTING at_dot.\n");
+          if (PTR_CHAR_POS ((unsigned char *) d) != point)
+            goto fail;
+          break;
+
+        case after_dot:
+          DEBUG_PRINT1 ("EXECUTING after_dot.\n");
+          if (PTR_CHAR_POS ((unsigned char *) d) <= point)
+            goto fail;
+          break;
+#else /* not emacs19 */
+        case at_dot:
+          DEBUG_PRINT1 ("EXECUTING at_dot.\n");
+          if (PTR_CHAR_POS ((unsigned char *) d) + 1 != point)
+            goto fail;
+          break;
+#endif /* not emacs19 */
+
+        case syntaxspec:
+          DEBUG_PRINT2 ("EXECUTING syntaxspec %d.\n", mcnt);
+          mcnt = *p++;
+          goto matchsyntax;
+
+        case wordchar:
+          DEBUG_PRINT1 ("EXECUTING Emacs wordchar.\n");
+          mcnt = (int) Sword;
+        matchsyntax:
+          PREFETCH ();
+          if (SYNTAX (*d++) != (enum syntaxcode) mcnt)
+            goto fail;
+          SET_REGS_MATCHED ();
+          break;
+
+        case notsyntaxspec:
+          DEBUG_PRINT2 ("EXECUTING notsyntaxspec %d.\n", mcnt);
+          mcnt = *p++;
+          goto matchnotsyntax;
+
+        case notwordchar:
+          DEBUG_PRINT1 ("EXECUTING Emacs notwordchar.\n");
+          mcnt = (int) Sword;
+        matchnotsyntax:
+          PREFETCH ();
+          if (SYNTAX (*d++) == (enum syntaxcode) mcnt)
+            goto fail;
+          SET_REGS_MATCHED ();
+          break;
+
+#else /* not emacs */
+        case wordchar:
+          DEBUG_PRINT1 ("EXECUTING non-Emacs wordchar.\n");
+          PREFETCH ();
+          if (!WORDCHAR_P (d))
+            goto fail;
+          SET_REGS_MATCHED ();
+          d++;
+          break;
+
+        case notwordchar:
+          DEBUG_PRINT1 ("EXECUTING non-Emacs notwordchar.\n");
+          PREFETCH ();
+          if (WORDCHAR_P (d))
+            goto fail;
+          SET_REGS_MATCHED ();
+          d++;
+          break;
+#endif /* not emacs */
+
+        default:
+          abort ();
+        }
+      continue;  /* Successfully executed one pattern command; keep going.  */
+
+
+    /* We goto here if a matching operation fails. */
+    fail:
+      if (!FAIL_STACK_EMPTY ())
+        { /* A restart point is known.  Restore to that state.  */
+          DEBUG_PRINT1 ("\nFAIL:\n");
+          POP_FAILURE_POINT (d, p,
+                             lowest_active_reg, highest_active_reg,
+                             regstart, regend, reg_info);
+
+          /* If this failure point is a dummy, try the next one.  */
+          if (!p)
+            goto fail;
+
+          /* If we failed to the end of the pattern, don't examine *p.  */
+          assert (p <= pend);
+          if (p < pend)
+            {
+              boolean is_a_jump_n = false;
+
+              /* If failed to a backwards jump that's part of a repetition
+                 loop, need to pop this failure point and use the next one.  */
+              switch ((re_opcode_t) *p)
+                {
+                case jump_n:
+                  is_a_jump_n = true;
+                case maybe_pop_jump:
+                case pop_failure_jump:
+                case jump:
+                  p1 = p + 1;
+                  EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+                  p1 += mcnt;
+
+                  if ((is_a_jump_n && (re_opcode_t) *p1 == succeed_n)
+                      || (!is_a_jump_n
+                          && (re_opcode_t) *p1 == on_failure_jump))
+                    goto fail;
+                  break;
+                default:
+                  /* do nothing */ ;
+                }
+            }
+
+          if (d >= string1 && d <= end1)
+            dend = end_match_1;
+        }
+      else
+        break;   /* Matching at this starting point really fails.  */
+    } /* for (;;) */
+
+  if (best_regs_set)
+    goto restore_best_regs;
+
+  FREE_VARIABLES ();
+
+  return -1;                            /* Failure to match.  */
+} /* re_match_2 */
+
+/* Subroutine definitions for re_match_2.  */
+
+
+/* We are passed P pointing to a register number after a start_memory.
+
+   Return true if the pattern up to the corresponding stop_memory can
+   match the empty string, and false otherwise.
+
+   If we find the matching stop_memory, sets P to point to one past its number.
+   Otherwise, sets P to an undefined byte less than or equal to END.
+
+   We don't handle duplicates properly (yet).  */
+
+static boolean
+group_match_null_string_p (p, end, reg_info)
+    unsigned char **p, *end;
+    register_info_type *reg_info;
+{
+  int mcnt;
+  /* Point to after the args to the start_memory.  */
+  unsigned char *p1 = *p + 2;
+
+  while (p1 < end)
+    {
+      /* Skip over opcodes that can match nothing, and return true or
+         false, as appropriate, when we get to one that can't, or to the
+         matching stop_memory.  */
+
+      switch ((re_opcode_t) *p1)
+        {
+        /* Could be either a loop or a series of alternatives.  */
+        case on_failure_jump:
+          p1++;
+          EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+
+          /* If the next operation is not a jump backwards in the
+             pattern.  */
+
+          if (mcnt >= 0)
+            {
+              /* Go through the on_failure_jumps of the alternatives,
+                 seeing if any of the alternatives cannot match nothing.
+                 The last alternative starts with only a jump,
+                 whereas the rest start with on_failure_jump and end
+                 with a jump, e.g., here is the pattern for `a|b|c':
+
+                 /on_failure_jump/0/6/exactn/1/a/jump_past_alt/0/6
+                 /on_failure_jump/0/6/exactn/1/b/jump_past_alt/0/3
+                 /exactn/1/c
+
+                 So, we have to first go through the first (n-1)
+                 alternatives and then deal with the last one separately.  */
+
+
+              /* Deal with the first (n-1) alternatives, which start
+                 with an on_failure_jump (see above) that jumps to right
+                 past a jump_past_alt.  */
+
+              while ((re_opcode_t) p1[mcnt-3] == jump_past_alt)
+                {
+                  /* `mcnt' holds how many bytes long the alternative
+                     is, including the ending `jump_past_alt' and
+                     its number.  */
+
+                  if (!alt_match_null_string_p (p1, p1 + mcnt - 3,
+                                                      reg_info))
+                    return false;
+
+                  /* Move to right after this alternative, including the
+                     jump_past_alt.  */
+                  p1 += mcnt;
+
+                  /* Break if it's the beginning of an n-th alternative
+                     that doesn't begin with an on_failure_jump.  */
+                  if ((re_opcode_t) *p1 != on_failure_jump)
+                    break;
+
+                  /* Still have to check that it's not an n-th
+                     alternative that starts with an on_failure_jump.  */
+                  p1++;
+                  EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+                  if ((re_opcode_t) p1[mcnt-3] != jump_past_alt)
+                    {
+                      /* Get to the beginning of the n-th alternative.  */
+                      p1 -= 3;
+                      break;
+                    }
+                }
+
+              /* Deal with the last alternative: go back and get number
+                 of the `jump_past_alt' just before it.  `mcnt' contains
+                 the length of the alternative.  */
+              EXTRACT_NUMBER (mcnt, p1 - 2);
+
+              if (!alt_match_null_string_p (p1, p1 + mcnt, reg_info))
+                return false;
+
+              p1 += mcnt;       /* Get past the n-th alternative.  */
+            } /* if mcnt > 0 */
+          break;
+
+
+        case stop_memory:
+          assert (p1[1] == **p);
+          *p = p1 + 2;
+          return true;
+
+
+        default:
+          if (!common_op_match_null_string_p (&p1, end, reg_info))
+            return false;
+        }
+    } /* while p1 < end */
+
+  return false;
+} /* group_match_null_string_p */
+
+
+/* Similar to group_match_null_string_p, but doesn't deal with alternatives:
+   It expects P to be the first byte of a single alternative and END one
+   byte past the last. The alternative can contain groups.  */
+
+static boolean
+alt_match_null_string_p (p, end, reg_info)
+    unsigned char *p, *end;
+    register_info_type *reg_info;
+{
+  int mcnt;
+  unsigned char *p1 = p;
+
+  while (p1 < end)
+    {
+      /* Skip over opcodes that can match nothing, and break when we get
+         to one that can't.  */
+
+      switch ((re_opcode_t) *p1)
+        {
+        /* It's a loop.  */
+        case on_failure_jump:
+          p1++;
+          EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+          p1 += mcnt;
+          break;
+
+        default:
+          if (!common_op_match_null_string_p (&p1, end, reg_info))
+            return false;
+        }
+    }  /* while p1 < end */
+
+  return true;
+} /* alt_match_null_string_p */
+
+
+/* Deals with the ops common to group_match_null_string_p and
+   alt_match_null_string_p.
+
+   Sets P to one after the op and its arguments, if any.  */
+
+static boolean
+common_op_match_null_string_p (p, end, reg_info)
+    unsigned char **p, *end;
+    register_info_type *reg_info;
+{
+  int mcnt;
+  boolean ret;
+  int reg_no;
+  unsigned char *p1 = *p;
+
+  switch ((re_opcode_t) *p1++)
+    {
+    case no_op:
+    case begline:
+    case endline:
+    case begbuf:
+    case endbuf:
+    case wordbeg:
+    case wordend:
+    case wordbound:
+    case notwordbound:
+#ifdef emacs
+    case before_dot:
+    case at_dot:
+    case after_dot:
+#endif
+      break;
+
+    case start_memory:
+      reg_no = *p1;
+      assert (reg_no > 0 && reg_no <= MAX_REGNUM);
+      ret = group_match_null_string_p (&p1, end, reg_info);
+
+      /* Have to set this here in case we're checking a group which
+         contains a group and a back reference to it.  */
+
+      if (REG_MATCH_NULL_STRING_P (reg_info[reg_no]) == MATCH_NULL_UNSET_VALUE)
+        REG_MATCH_NULL_STRING_P (reg_info[reg_no]) = ret;
+
+      if (!ret)
+        return false;
+      break;
+
+    /* If this is an optimized succeed_n for zero times, make the jump.  */
+    case jump:
+      EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+      if (mcnt >= 0)
+        p1 += mcnt;
+      else
+        return false;
+      break;
+
+    case succeed_n:
+      /* Get to the number of times to succeed.  */
+      p1 += 2;
+      EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+
+      if (mcnt == 0)
+        {
+          p1 -= 4;
+          EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+          p1 += mcnt;
+        }
+      else
+        return false;
+      break;
+
+    case duplicate:
+      if (!REG_MATCH_NULL_STRING_P (reg_info[*p1]))
+        return false;
+      break;
+
+    case set_number_at:
+      p1 += 4;
+
+    default:
+      /* All other opcodes mean we cannot match the empty string.  */
+      return false;
+  }
+
+  *p = p1;
+  return true;
+} /* common_op_match_null_string_p */
+
+
+/* Return zero if TRANSLATE[S1] and TRANSLATE[S2] are identical for LEN
+   bytes; nonzero otherwise.  */
+
+static int
+bcmp_translate(
+     unsigned char *s1,
+     unsigned char *s2,
+     int len,
+     char *translate
+)
+{
+  register unsigned char *p1 = s1, *p2 = s2;
+  while (len)
+    {
+      if (translate[*p1++] != translate[*p2++]) return 1;
+      len--;
+    }
+  return 0;
+}
+
+/* Entry points for GNU code.  */
+
+/* re_compile_pattern is the GNU regular expression compiler: it
+   compiles PATTERN (of length SIZE) and puts the result in BUFP.
+   Returns 0 if the pattern was valid, otherwise an error string.
+
+   Assumes the `allocated' (and perhaps `buffer') and `translate' fields
+   are set in BUFP on entry.
+
+   We call regex_compile to do the actual compilation.  */
+
+const char *
+re_compile_pattern (pattern, length, bufp)
+     const char *pattern;
+     int length;
+     struct re_pattern_buffer *bufp;
+{
+  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).  */
+  bufp->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.  */
+  bufp->no_sub = 0;
+
+  /* Match anchors at newline.  */
+  bufp->newline_anchor = 1;
+
+  ret = regex_compile (pattern, length, re_syntax_options, bufp);
+
+  return re_error_msg[(int) ret];
+}
+
+/* Entry points compatible with 4.2 BSD regex library.  We don't define
+   them if this is an Emacs or POSIX compilation.  */
+
+#if !defined (emacs) && !defined (_POSIX_SOURCE)
+
+/* BSD has one and only one pattern buffer.  */
+static struct re_pattern_buffer re_comp_buf;
+
+char *
+re_comp (s)
+    const char *s;
+{
+  reg_errcode_t ret;
+
+  if (!s)
+    {
+      if (!re_comp_buf.buffer)
+        return "No previous regular expression";
+      return 0;
+    }
+
+  if (!re_comp_buf.buffer)
+    {
+      re_comp_buf.buffer = (unsigned char *) malloc (200);
+      if (re_comp_buf.buffer == NULL)
+        return "Memory exhausted";
+      re_comp_buf.allocated = 200;
+
+      re_comp_buf.fastmap = (char *) malloc (1 << BYTEWIDTH);
+      if (re_comp_buf.fastmap == NULL)
+        return "Memory exhausted";
+    }
+
+  /* Since `re_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.  */
+  re_comp_buf.newline_anchor = 1;
+
+  ret = regex_compile (s, strlen (s), re_syntax_options, &re_comp_buf);
+
+  /* Yes, we're discarding `const' here.  */
+  return (char *) re_error_msg[(int) ret];
+}
+
+
+int
+re_exec (s)
+    const char *s;
+{
+  const int len = strlen (s);
+  return
+    0 <= re_search (&re_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.  */
+
+#ifndef 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.)  */
+
+int
+regcomp (preg, pattern, cflags)
+    regex_t *preg;
+    const char *pattern;
+    int cflags;
+{
+  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;
+
+  /* Don't bother to use a fastmap when searching.  This simplifies the
+     REG_NEWLINE case: if we used a fastmap, we'd have to put all the
+     characters after newlines into the fastmap.  This way, we just try
+     every character.  */
+  preg->fastmap = 0;
+
+  if (cflags & REG_ICASE)
+    {
+      unsigned i;
+
+      preg->translate = (char *) malloc (CHAR_SET_SIZE);
+      if (preg->translate == NULL)
+        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 = NULL;
+
+  /* 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.  */
+  ret = regex_compile (pattern, strlen (pattern), syntax, preg);
+
+  /* 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.  */
+
+int
+regexec (preg, string, nmatch, pmatch, eflags)
+    const regex_t *preg;
+    const char *string;
+    size_t nmatch;
+    regmatch_t pmatch[];
+    int eflags;
+{
+  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 = TALLOC (nmatch, regoff_t);
+      regs.end = TALLOC (nmatch, regoff_t);
+      if (regs.start == NULL || regs.end == NULL)
+        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.   We don't use PREG here.  */
+
+size_t
+regerror (errcode, preg, errbuf, errbuf_size)
+    int errcode;
+    const regex_t *preg;
+    char *errbuf;
+    size_t errbuf_size;
+{
+  const char *msg;
+  size_t msg_size;
+
+  if (errcode < 0
+      || errcode >= (sizeof (re_error_msg) / sizeof (re_error_msg[0])))
+    /* Only error codes returned by the rest of the code should be passed
+       to this routine.  If we are given anything else, or if other regex
+       code generates an invalid error code, then the program has a bug.
+       Dump core so we can fix it.  */
+    abort ();
+
+  msg = re_error_msg[errcode];
+
+  /* POSIX doesn't require that we do anything in this case, but why
+     not be nice.  */
+  if (! msg)
+    msg = "Success";
+
+  msg_size = strlen (msg) + 1; /* Includes the null.  */
+
+  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.  */
+
+void
+regfree (preg)
+    regex_t *preg;
+{
+  if (preg->buffer != NULL)
+    free (preg->buffer);
+  preg->buffer = NULL;
+
+  preg->allocated = 0;
+  preg->used = 0;
+
+  if (preg->fastmap != NULL)
+    free (preg->fastmap);
+  preg->fastmap = NULL;
+  preg->fastmap_accurate = 0;
+
+  if (preg->translate != NULL)
+    free (preg->translate);
+  preg->translate = NULL;
+}
+
+#endif /* not emacs  */
+
+/*
+Local variables:
+make-backup-files: t
+version-control: t
+trim-versions-without-asking: nil
+End:
+*/
diff --git a/win32/regex.h b/win32/regex.h
new file mode 100644
index 000000000..6eb64f140
--- /dev/null
+++ b/win32/regex.h
@@ -0,0 +1,490 @@
+/* Definitions for data structures and routines for the regular
+   expression library, version 0.12.
+
+   Copyright (C) 1985, 1989, 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program 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 General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#ifndef __REGEXP_LIBRARY_H__
+#define __REGEXP_LIBRARY_H__
+
+/* POSIX says that <sys/types.h> must be included (by the caller) before
+   <regex.h>.  */
+
+#ifdef VMS
+/* VMS doesn't have `size_t' in <sys/types.h>, even though POSIX says it
+   should be there.  */
+#include <stddef.h>
+#endif
+
+
+/* The following bits are used to determine the regexp syntax we
+   recognize.  The set/not-set meanings are chosen so that Emacs syntax
+   remains the value 0.  The bits are given in alphabetical order, and
+   the definitions shifted by one from the previous bit; thus, when we
+   add or remove a bit, only one other definition need change.  */
+typedef unsigned reg_syntax_t;
+
+/* If this bit is not set, then \ inside a bracket expression is literal.
+   If set, then such a \ quotes the following character.  */
+#define RE_BACKSLASH_ESCAPE_IN_LISTS (1)
+
+/* If this bit is not set, then + and ? are operators, and \+ and \? are
+     literals.
+   If set, then \+ and \? are operators and + and ? are literals.  */
+#define RE_BK_PLUS_QM (RE_BACKSLASH_ESCAPE_IN_LISTS << 1)
+
+/* If this bit is set, then character classes are supported.  They are:
+     [:alpha:], [:upper:], [:lower:],  [:digit:], [:alnum:], [:xdigit:],
+     [:space:], [:print:], [:punct:], [:graph:], and [:cntrl:].
+   If not set, then character classes are not supported.  */
+#define RE_CHAR_CLASSES (RE_BK_PLUS_QM << 1)
+
+/* If this bit is set, then ^ and $ are always anchors (outside bracket
+     expressions, of course).
+   If this bit is not set, then it depends:
+        ^  is an anchor if it is at the beginning of a regular
+           expression or after an open-group or an alternation operator;
+        $  is an anchor if it is at the end of a regular expression, or
+           before a close-group or an alternation operator.
+
+   This bit could be (re)combined with RE_CONTEXT_INDEP_OPS, because
+   POSIX draft 11.2 says that * etc. in leading positions is undefined.
+   We already implemented a previous draft which made those constructs
+   invalid, though, so we haven't changed the code back.  */
+#define RE_CONTEXT_INDEP_ANCHORS (RE_CHAR_CLASSES << 1)
+
+/* If this bit is set, then special characters are always special
+     regardless of where they are in the pattern.
+   If this bit is not set, then special characters are special only in
+     some contexts; otherwise they are ordinary.  Specifically,
+     * + ? and intervals are only special when not after the beginning,
+     open-group, or alternation operator.  */
+#define RE_CONTEXT_INDEP_OPS (RE_CONTEXT_INDEP_ANCHORS << 1)
+
+/* If this bit is set, then *, +, ?, and { cannot be first in an re or
+     immediately after an alternation or begin-group operator.  */
+#define RE_CONTEXT_INVALID_OPS (RE_CONTEXT_INDEP_OPS << 1)
+
+/* If this bit is set, then . matches newline.
+   If not set, then it doesn't.  */
+#define RE_DOT_NEWLINE (RE_CONTEXT_INVALID_OPS << 1)
+
+/* If this bit is set, then . doesn't match NUL.
+   If not set, then it does.  */
+#define RE_DOT_NOT_NULL (RE_DOT_NEWLINE << 1)
+
+/* If this bit is set, nonmatching lists [^...] do not match newline.
+   If not set, they do.  */
+#define RE_HAT_LISTS_NOT_NEWLINE (RE_DOT_NOT_NULL << 1)
+
+/* If this bit is set, either \{...\} or {...} defines an
+     interval, depending on RE_NO_BK_BRACES.
+   If not set, \{, \}, {, and } are literals.  */
+#define RE_INTERVALS (RE_HAT_LISTS_NOT_NEWLINE << 1)
+
+/* If this bit is set, +, ? and | aren't recognized as operators.
+   If not set, they are.  */
+#define RE_LIMITED_OPS (RE_INTERVALS << 1)
+
+/* If this bit is set, newline is an alternation operator.
+   If not set, newline is literal.  */
+#define RE_NEWLINE_ALT (RE_LIMITED_OPS << 1)
+
+/* If this bit is set, then `{...}' defines an interval, and \{ and \}
+     are literals.
+  If not set, then `\{...\}' defines an interval.  */
+#define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
+
+/* If this bit is set, (...) defines a group, and \( and \) are literals.
+   If not set, \(...\) defines a group, and ( and ) are literals.  */
+#define RE_NO_BK_PARENS (RE_NO_BK_BRACES << 1)
+
+/* If this bit is set, then \<digit> matches <digit>.
+   If not set, then \<digit> is a back-reference.  */
+#define RE_NO_BK_REFS (RE_NO_BK_PARENS << 1)
+
+/* If this bit is set, then | is an alternation operator, and \| is literal.
+   If not set, then \| is an alternation operator, and | is literal.  */
+#define RE_NO_BK_VBAR (RE_NO_BK_REFS << 1)
+
+/* If this bit is set, then an ending range point collating higher
+     than the starting range point, as in [z-a], is invalid.
+   If not set, then when ending range point collates higher than the
+     starting range point, the range is ignored.  */
+#define RE_NO_EMPTY_RANGES (RE_NO_BK_VBAR << 1)
+
+/* If this bit is set, then an unmatched ) is ordinary.
+   If not set, then an unmatched ) is invalid.  */
+#define RE_UNMATCHED_RIGHT_PAREN_ORD (RE_NO_EMPTY_RANGES << 1)
+
+/* This global variable defines the particular regexp syntax to use (for
+   some interfaces).  When a regexp is compiled, the syntax used is
+   stored in the pattern buffer, so changing this does not affect
+   already-compiled regexps.  */
+extern reg_syntax_t re_syntax_options;
+
+/* Define combinations of the above bits for the standard possibilities.
+   (The [[[ comments delimit what gets put into the Texinfo file, so
+   don't delete them!)  */
+/* [[[begin syntaxes]]] */
+#define RE_SYNTAX_EMACS 0
+
+#define RE_SYNTAX_AWK                                                   \
+  (RE_BACKSLASH_ESCAPE_IN_LISTS | RE_DOT_NOT_NULL                       \
+   | RE_NO_BK_PARENS            | RE_NO_BK_REFS                         \
+   | RE_NO_BK_VBAR               | RE_NO_EMPTY_RANGES                   \
+   | RE_UNMATCHED_RIGHT_PAREN_ORD)
+
+#define RE_SYNTAX_POSIX_AWK                                             \
+  (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS)
+
+#define RE_SYNTAX_GREP                                                  \
+  (RE_BK_PLUS_QM              | RE_CHAR_CLASSES                         \
+   | RE_HAT_LISTS_NOT_NEWLINE | RE_INTERVALS                            \
+   | RE_NEWLINE_ALT)
+
+#define RE_SYNTAX_EGREP                                                 \
+  (RE_CHAR_CLASSES        | RE_CONTEXT_INDEP_ANCHORS                    \
+   | RE_CONTEXT_INDEP_OPS | RE_HAT_LISTS_NOT_NEWLINE                    \
+   | RE_NEWLINE_ALT       | RE_NO_BK_PARENS                             \
+   | RE_NO_BK_VBAR)
+
+#define RE_SYNTAX_POSIX_EGREP                                           \
+  (RE_SYNTAX_EGREP | RE_INTERVALS | RE_NO_BK_BRACES)
+
+/* P1003.2/D11.2, section 4.20.7.1, lines 5078ff.  */
+#define RE_SYNTAX_ED RE_SYNTAX_POSIX_BASIC
+
+#define RE_SYNTAX_SED RE_SYNTAX_POSIX_BASIC
+
+/* Syntax bits common to both basic and extended POSIX regex syntax.  */
+#define _RE_SYNTAX_POSIX_COMMON                                         \
+  (RE_CHAR_CLASSES | RE_DOT_NEWLINE      | RE_DOT_NOT_NULL              \
+   | RE_INTERVALS  | RE_NO_EMPTY_RANGES)
+
+#define RE_SYNTAX_POSIX_BASIC                                           \
+  (_RE_SYNTAX_POSIX_COMMON | RE_BK_PLUS_QM)
+
+/* Differs from ..._POSIX_BASIC only in that RE_BK_PLUS_QM becomes
+   RE_LIMITED_OPS, i.e., \? \+ \| are not recognized.  Actually, this
+   isn't minimal, since other operators, such as \`, aren't disabled.  */
+#define RE_SYNTAX_POSIX_MINIMAL_BASIC                                   \
+  (_RE_SYNTAX_POSIX_COMMON | RE_LIMITED_OPS)
+
+#define RE_SYNTAX_POSIX_EXTENDED                                        \
+  (_RE_SYNTAX_POSIX_COMMON | RE_CONTEXT_INDEP_ANCHORS                   \
+   | RE_CONTEXT_INDEP_OPS  | RE_NO_BK_BRACES                            \
+   | RE_NO_BK_PARENS       | RE_NO_BK_VBAR                              \
+   | RE_UNMATCHED_RIGHT_PAREN_ORD)
+
+/* Differs from ..._POSIX_EXTENDED in that RE_CONTEXT_INVALID_OPS
+   replaces RE_CONTEXT_INDEP_OPS and RE_NO_BK_REFS is added.  */
+#define RE_SYNTAX_POSIX_MINIMAL_EXTENDED                                \
+  (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS                  \
+   | RE_CONTEXT_INVALID_OPS | RE_NO_BK_BRACES                           \
+   | RE_NO_BK_PARENS        | RE_NO_BK_REFS                             \
+   | RE_NO_BK_VBAR          | RE_UNMATCHED_RIGHT_PAREN_ORD)
+/* [[[end syntaxes]]] */
+
+/* Maximum number of duplicates an interval can allow.  Some systems
+   (erroneously) define this in other header files, but we want our
+   value, so remove any previous define.  */
+#ifdef RE_DUP_MAX
+#undef RE_DUP_MAX
+#endif
+#define RE_DUP_MAX ((1 << 15) - 1)
+
+
+/* POSIX `cflags' bits (i.e., information for `regcomp').  */
+
+/* If this bit is set, then use extended regular expression syntax.
+   If not set, then use basic regular expression syntax.  */
+#define REG_EXTENDED 1
+
+/* If this bit is set, then ignore case when matching.
+   If not set, then case is significant.  */
+#define REG_ICASE (REG_EXTENDED << 1)
+
+/* If this bit is set, then anchors do not match at newline
+     characters in the string.
+   If not set, then anchors do match at newlines.  */
+#define REG_NEWLINE (REG_ICASE << 1)
+
+/* If this bit is set, then report only success or fail in regexec.
+   If not set, then returns differ between not matching and errors.  */
+#define REG_NOSUB (REG_NEWLINE << 1)
+
+
+/* POSIX `eflags' bits (i.e., information for regexec).  */
+
+/* If this bit is set, then the beginning-of-line operator doesn't match
+     the beginning of the string (presumably because it's not the
+     beginning of a line).
+   If not set, then the beginning-of-line operator does match the
+     beginning of the string.  */
+#define REG_NOTBOL 1
+
+/* Like REG_NOTBOL, except for the end-of-line.  */
+#define REG_NOTEOL (1 << 1)
+
+
+/* If any error codes are removed, changed, or added, update the
+   `re_error_msg' table in regex.c.  */
+typedef enum
+{
+  REG_NOERROR = 0,      /* Success.  */
+  REG_NOMATCH,          /* Didn't find a match (for regexec).  */
+
+  /* POSIX regcomp return error codes.  (In the order listed in the
+     standard.)  */
+  REG_BADPAT,           /* Invalid pattern.  */
+  REG_ECOLLATE,         /* Not implemented.  */
+  REG_ECTYPE,           /* Invalid character class name.  */
+  REG_EESCAPE,          /* Trailing backslash.  */
+  REG_ESUBREG,          /* Invalid back reference.  */
+  REG_EBRACK,           /* Unmatched left bracket.  */
+  REG_EPAREN,           /* Parenthesis imbalance.  */
+  REG_EBRACE,           /* Unmatched \{.  */
+  REG_BADBR,            /* Invalid contents of \{\}.  */
+  REG_ERANGE,           /* Invalid range end.  */
+  REG_ESPACE,           /* Ran out of memory.  */
+  REG_BADRPT,           /* No preceding re for repetition op.  */
+
+  /* Error codes we've added.  */
+  REG_EEND,             /* Premature end.  */
+  REG_ESIZE,            /* Compiled pattern bigger than 2^16 bytes.  */
+  REG_ERPAREN           /* Unmatched ) or \); not returned from regcomp.  */
+} reg_errcode_t;
+
+/* This data structure represents a compiled pattern.  Before calling
+   the pattern compiler, the fields `buffer', `allocated', `fastmap',
+   `translate', and `no_sub' can be set.  After the pattern has been
+   compiled, the `re_nsub' field is available.  All other fields are
+   private to the regex routines.  */
+
+struct re_pattern_buffer
+{
+/* [[[begin pattern_buffer]]] */
+        /* Space that holds the compiled pattern.  It is declared as
+          `unsigned char *' because its elements are
+           sometimes used as array indexes.  */
+  unsigned char *buffer;
+
+        /* Number of bytes to which `buffer' points.  */
+  unsigned long allocated;
+
+        /* Number of bytes actually used in `buffer'.  */
+  unsigned long used;
+
+        /* Syntax setting with which the pattern was compiled.  */
+  reg_syntax_t syntax;
+
+        /* Pointer to a fastmap, if any, otherwise zero.  re_search uses
+           the fastmap, if there is one, to skip over impossible
+           starting points for matches.  */
+  char *fastmap;
+
+        /* Either a translate table to apply to all characters before
+           comparing them, or zero for no translation.  The translation
+           is applied to a pattern when it is compiled and to a string
+           when it is matched.  */
+  char *translate;
+
+        /* Number of subexpressions found by the compiler.  */
+  size_t re_nsub;
+
+        /* Zero if this pattern cannot match the empty string, one else.
+           Well, in truth it's used only in `re_search_2', to see
+           whether or not we should use the fastmap, so we don't set
+           this absolutely perfectly; see `re_compile_fastmap' (the
+           `duplicate' case).  */
+  unsigned can_be_null : 1;
+
+        /* If REGS_UNALLOCATED, allocate space in the `regs' structure
+             for `max (RE_NREGS, re_nsub + 1)' groups.
+           If REGS_REALLOCATE, reallocate space if necessary.
+           If REGS_FIXED, use what's there.  */
+#define REGS_UNALLOCATED 0
+#define REGS_REALLOCATE 1
+#define REGS_FIXED 2
+  unsigned regs_allocated : 2;
+
+        /* Set to zero when `regex_compile' compiles a pattern; set to one
+           by `re_compile_fastmap' if it updates the fastmap.  */
+  unsigned fastmap_accurate : 1;
+
+        /* If set, `re_match_2' does not return information about
+           subexpressions.  */
+  unsigned no_sub : 1;
+
+        /* If set, a beginning-of-line anchor doesn't match at the
+           beginning of the string.  */
+  unsigned not_bol : 1;
+
+        /* Similarly for an end-of-line anchor.  */
+  unsigned not_eol : 1;
+
+        /* If true, an anchor at a newline matches.  */
+  unsigned newline_anchor : 1;
+
+/* [[[end pattern_buffer]]] */
+};
+
+typedef struct re_pattern_buffer regex_t;
+
+
+/* search.c (search_buffer) in Emacs needs this one opcode value.  It is
+   defined both in `regex.c' and here.  */
+#define RE_EXACTN_VALUE 1
+
+/* Type for byte offsets within the string.  POSIX mandates this.  */
+typedef int regoff_t;
+
+
+/* This is the structure we store register match data in.  See
+   regex.texinfo for a full description of what registers match.  */
+struct re_registers
+{
+  unsigned num_regs;
+  regoff_t *start;
+  regoff_t *end;
+};
+
+
+/* If `regs_allocated' is REGS_UNALLOCATED in the pattern buffer,
+   `re_match_2' returns information about at least this many registers
+   the first time a `regs' structure is passed.  */
+#ifndef RE_NREGS
+#define RE_NREGS 30
+#endif
+
+
+/* POSIX specification for registers.  Aside from the different names than
+   `re_registers', POSIX uses an array of structures, instead of a
+   structure of arrays.  */
+typedef struct
+{
+  regoff_t rm_so;  /* Byte offset from string's start to substring's start.  */
+  regoff_t rm_eo;  /* Byte offset from string's start to substring's end.  */
+} regmatch_t;
+
+/* Declarations for routines.  */
+
+/* To avoid duplicating every routine declaration -- once with a
+   prototype (if we are ANSI), and once without (if we aren't) -- we
+   use the following macro to declare argument types.  This
+   unfortunately clutters up the declarations a bit, but I think it's
+   worth it.  */
+
+#if __STDC__
+
+#define _RE_ARGS(args) args
+
+#else /* not __STDC__ */
+
+#define _RE_ARGS(args) ()
+
+#endif /* not __STDC__ */
+
+/* Sets the current default syntax to SYNTAX, and return the old syntax.
+   You can also simply assign to the `re_syntax_options' variable.  */
+extern reg_syntax_t re_set_syntax _RE_ARGS ((reg_syntax_t syntax));
+
+/* Compile the regular expression PATTERN, with length LENGTH
+   and syntax given by the global `re_syntax_options', into the buffer
+   BUFFER.  Return NULL if successful, and an error string if not.  */
+extern const char *re_compile_pattern
+  _RE_ARGS ((const char *pattern, int length,
+             struct re_pattern_buffer *buffer));
+
+
+/* Compile a fastmap for the compiled pattern in BUFFER; used to
+   accelerate searches.  Return 0 if successful and -2 if was an
+   internal error.  */
+extern int re_compile_fastmap _RE_ARGS ((struct re_pattern_buffer *buffer));
+
+
+/* Search in the string STRING (with length LENGTH) for the pattern
+   compiled into BUFFER.  Start searching at position START, for RANGE
+   characters.  Return the starting position of the match, -1 for no
+   match, or -2 for an internal error.  Also return register
+   information in REGS (if REGS and BUFFER->no_sub are nonzero).  */
+extern int re_search
+  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string,
+            int length, int start, int range, struct re_registers *regs));
+
+
+/* Like `re_search', but search in the concatenation of STRING1 and
+   STRING2.  Also, stop searching at index START + STOP.  */
+extern int re_search_2
+  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string1,
+             int length1, const char *string2, int length2,
+             int start, int range, struct re_registers *regs, int stop));
+
+
+/* Like `re_search', but return how many characters in STRING the regexp
+   in BUFFER matched, starting at position START.  */
+extern int re_match
+  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string,
+             int length, int start, struct re_registers *regs));
+
+
+/* Relates to `re_match' as `re_search_2' relates to `re_search'.  */
+extern int re_match_2
+  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string1,
+             int length1, const char *string2, int length2,
+             int start, struct re_registers *regs, int stop));
+
+
+/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
+   ENDS.  Subsequent matches using BUFFER and REGS will use this memory
+   for recording register information.  STARTS and ENDS must be
+   allocated with malloc, 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.  */
+extern void re_set_registers
+  _RE_ARGS ((struct re_pattern_buffer *buffer, struct re_registers *regs,
+             unsigned num_regs, regoff_t *starts, regoff_t *ends));
+
+/* 4.2 bsd compatibility.  */
+extern char *re_comp _RE_ARGS ((const char *));
+extern int re_exec _RE_ARGS ((const char *));
+
+/* POSIX compatibility.  */
+extern int regcomp _RE_ARGS ((regex_t *preg, const char *pattern, int cflags));
+extern int regexec
+  _RE_ARGS ((const regex_t *preg, const char *string, size_t nmatch,
+             regmatch_t pmatch[], int eflags));
+extern size_t regerror
+  _RE_ARGS ((int errcode, const regex_t *preg, char *errbuf,
+             size_t errbuf_size));
+extern void regfree _RE_ARGS ((regex_t *preg));
+
+#endif /* not __REGEXP_LIBRARY_H__ */
+
+/*
+Local variables:
+make-backup-files: t
+version-control: t
+trim-versions-without-asking: nil
+End:
+*/