Wed Jun 10 11:27:39 1998 Jason Molenda (crash@bugshack.cygnus.com)

        * gnu-regex.c, gnu-regex.h: Update to current FSF (glibc) versions.

1 files changed, 5348 insertions, 1300 deletions

diff --git a/gdb/gnu-regex.c b/gdb/gnu-regex.c
index dec0cf1..e2d31a0 100644
--- a/gdb/gnu-regex.c
+++ b/gdb/gnu-regex.c
@@ -1,59 +1,174 @@
-/* Extended regular expression matching and search library.
-   Copyright (C) 1985, 1989 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 of the License, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
-
-/* To test, compile with -Dtest.
- This Dtestable feature turns this into a self-contained program
- which reads a pattern, describes how it compiles,
- then reads a string and searches for it.  */
-
-#ifdef emacs
+/* Extended regular expression matching and search library,
+   version 0.12.
+   (Implements POSIX draft P1003.2/D11.2, except for some of the
+   internationalization features.)
+   Copyright (C) 1993, 94, 95, 96, 97, 98 Free Software Foundation, Inc.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+/* AIX requires this to be the first thing in the file. */
+#if defined _AIX && !defined REGEX_MALLOC
+  #pragma alloca
+#endif
 
-/* The `emacs' switch turns on certain special matching commands
- that make sense only in emacs. */
+#undef	_GNU_SOURCE
+#define _GNU_SOURCE
 
-#include "config.h"
-#include "lisp.h"
-#include "buffer.h"
-#include "syntax.h"
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
 
-#else  /* not emacs */
+#ifndef PARAMS
+# if defined __GNUC__ || (defined __STDC__ && __STDC__)
+#  define PARAMS(args) args
+# else
+#  define PARAMS(args) ()
+# endif  /* GCC.  */
+#endif  /* Not PARAMS.  */
 
-#include "defs.h"
-#include "gdb_string.h"
-#undef malloc
-#define malloc xmalloc
+#if defined STDC_HEADERS && !defined emacs
+# include <stddef.h>
+#else
+/* We need this for `regex.h', and perhaps for the Emacs include files.  */
+# include <sys/types.h>
+#endif
 
-/*
- * Define the syntax stuff, so we can do the \<...\> things.
- */
+/* For platform which support the ISO C amendement 1 functionality we
+   support user defined character classes.  */
+#if defined _LIBC || (defined HAVE_WCTYPE_H && defined HAVE_WCHAR_H)
+# include <wctype.h>
+# include <wchar.h>
+
+/* We have to keep the namespace clean.  */
+# define regfree(preg) __regfree (preg)
+# define regexec(pr, st, nm, pm, ef) __regexec (pr, st, nm, pm, ef)
+# define regcomp(preg, pattern, cflags) __regcomp (preg, pattern, cflags)
+# define regerror(errcode, preg, errbuf, errbuf_size) \
+	__regerror(errcode, preg, errbuf, errbuf_size)
+# define re_set_registers(bu, re, nu, st, en) \
+	__re_set_registers (bu, re, nu, st, en)
+# define re_match_2(bufp, string1, size1, string2, size2, pos, regs, stop) \
+	__re_match_2 (bufp, string1, size1, string2, size2, pos, regs, stop)
+# define re_match(bufp, string, size, pos, regs) \
+	__re_match (bufp, string, size, pos, regs)
+# define re_search(bufp, string, size, startpos, range, regs) \
+	__re_search (bufp, string, size, startpos, range, regs)
+# define re_compile_pattern(pattern, length, bufp) \
+	__re_compile_pattern (pattern, length, bufp)
+# define re_set_syntax(syntax) __re_set_syntax (syntax)
+# define re_search_2(bufp, st1, s1, st2, s2, startpos, range, regs, stop) \
+	__re_search_2 (bufp, st1, s1, st2, s2, startpos, range, regs, stop)
+# define re_compile_fastmap(bufp) __re_compile_fastmap (bufp)
+
+#define btowc __btowc
+#endif
 
-#ifndef Sword /* must be non-zero in some of the tests below... */
-#define Sword 1
+/* This is for other GNU distributions with internationalized messages.  */
+#if HAVE_LIBINTL_H || defined _LIBC
+# include <libintl.h>
+#else
+# define gettext(msgid) (msgid)
 #endif
 
-#define SYNTAX(c) re_syntax_table[c]
+#ifndef gettext_noop
+/* This define is so xgettext can find the internationalizable
+   strings.  */
+# define gettext_noop(String) String
+#endif
 
-#ifdef SYNTAX_TABLE
+/* The `emacs' switch turns on certain matching commands
+   that make sense only in Emacs. */
+#ifdef emacs
 
-char *re_syntax_table;
+# include "lisp.h"
+# include "buffer.h"
+# include "syntax.h"
 
-#else
+#else  /* not emacs */
 
-static char re_syntax_table[256];
+/* If we are not linking with Emacs proper,
+   we can't use the relocating allocator
+   even if config.h says that we can.  */
+# undef REL_ALLOC
+
+# if defined STDC_HEADERS || defined _LIBC
+#  include <stdlib.h>
+# else
+char *malloc ();
+char *realloc ();
+# endif
+
+/* When used in Emacs's lib-src, we need to get bzero and bcopy somehow.
+   If nothing else has been done, use the method below.  */
+# ifdef INHIBIT_STRING_HEADER
+#  if !(defined HAVE_BZERO && defined HAVE_BCOPY)
+#   if !defined bzero && !defined bcopy
+#    undef INHIBIT_STRING_HEADER
+#   endif
+#  endif
+# endif
+
+/* This is the normal way of making sure we have a bcopy and a bzero.
+   This is used in most programs--a few other programs avoid this
+   by defining INHIBIT_STRING_HEADER.  */
+# ifndef INHIBIT_STRING_HEADER
+#  if defined HAVE_STRING_H || defined STDC_HEADERS || defined _LIBC
+#   include <string.h>
+#   ifndef bzero
+#    ifndef _LIBC
+#     define bzero(s, n)	(memset (s, '\0', n), (s))
+#    else
+#     define bzero(s, n)	__bzero (s, n)
+#    endif
+#   endif
+#  else
+#   include <strings.h>
+#   ifndef memcmp
+#    define memcmp(s1, s2, n)	bcmp (s1, s2, n)
+#   endif
+#   ifndef memcpy
+#    define memcpy(d, s, n)	(bcopy (s, d, n), (d))
+#   endif
+#  endif
+# endif
+
+/* 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 SWITCH_ENUM_BUG
+#  define SWITCH_ENUM_CAST(x) ((int)(x))
+# else
+#  define SWITCH_ENUM_CAST(x) (x)
+# endif
+
+/* How many characters in the character set.  */
+# define CHAR_SET_SIZE 256
+
+# ifdef SYNTAX_TABLE
+
+extern char *re_syntax_table;
+
+# else /* not SYNTAX_TABLE */
+
+static char re_syntax_table[CHAR_SET_SIZE];
 
 static void
 init_syntax_once ()
@@ -64,7 +179,7 @@ init_syntax_once ()
    if (done)
      return;
 
-   memset (re_syntax_table, '\0', sizeof re_syntax_table);
+   bzero (re_syntax_table, sizeof re_syntax_table);
 
    for (c = 'a'; c <= 'z'; c++)
      re_syntax_table[c] = Sword;
@@ -75,25 +190,68 @@ init_syntax_once ()
    for (c = '0'; c <= '9'; c++)
      re_syntax_table[c] = Sword;
 
+   re_syntax_table['_'] = Sword;
+
    done = 1;
 }
 
-#endif /* SYNTAX_TABLE */
-#endif /* not emacs */
-
-#include "gnu-regex.h"
+# endif /* not SYNTAX_TABLE */
 
-/* Number of failure points to allocate space for initially,
- when matching.  If this number is exceeded, more space is allocated,
- so it is not a hard limit.  */
+# define SYNTAX(c) re_syntax_table[c]
 
-#ifndef NFAILURES
-#define NFAILURES 80
-#endif /* NFAILURES */
+#endif /* not emacs */
+
+/* Get the interface, including the syntax bits.  */
+#include "regex.h"
+
+/* isalpha etc. are used for the character classes.  */
+#include <ctype.h>
+
+/* Jim Meyering writes:
+
+   "... Some ctype macros are valid only for character codes that
+   isascii says are ASCII (SGI's IRIX-4.0.5 is one such system --when
+   using /bin/cc or gcc but without giving an ansi option).  So, all
+   ctype uses should be through macros like ISPRINT...  If
+   STDC_HEADERS is defined, then autoconf has verified that the ctype
+   macros don't need to be guarded with references to isascii. ...
+   Defining isascii to 1 should let any compiler worth its salt
+   eliminate the && through constant folding."
+   Solaris defines some of these symbols so we must undefine them first.  */
+
+#undef ISASCII
+#if defined STDC_HEADERS || (!defined isascii && !defined HAVE_ISASCII)
+# define ISASCII(c) 1
+#else
+# define ISASCII(c) isascii(c)
+#endif
 
-/* width of a byte in bits */
+#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 BYTEWIDTH 8
+#undef ISPRINT
+#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 (void *)0
+#endif
 
 /* We remove any previous definition of `SIGN_EXTEND_CHAR',
    since ours (we hope) works properly with all combinations of
@@ -101,726 +259,2967 @@ init_syntax_once ()
    (Per Bothner suggested the basic approach.)  */
 #undef SIGN_EXTEND_CHAR
 #if __STDC__
-#define SIGN_EXTEND_CHAR(c) ((signed char) (c))
+# 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)
+# define SIGN_EXTEND_CHAR(c) ((((unsigned char) (c)) ^ 128) - 128)
 #endif
 
-static int obscure_syntax = 0;
+/* 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.
 
-/* Specify the precise syntax of regexp for compilation.
-   This provides for compatibility for various utilities
-   which historically have different, incompatible syntaxes.
+   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.  */
 
-   The argument SYNTAX is a bit-mask containing the two bits
-   RE_NO_BK_PARENS and RE_NO_BK_VBAR.  */
+#ifdef REGEX_MALLOC
 
-int
-re_set_syntax (syntax)
-     int syntax;
+# define REGEX_ALLOCATE malloc
+# define REGEX_REALLOCATE(source, osize, nsize) realloc (source, nsize)
+# define REGEX_FREE free
+
+#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>
+#   endif /* 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),				\
+   memcpy (destination, source, osize))
+
+/* No need to do anything to free, after alloca.  */
+# define REGEX_FREE(arg) ((void)0) /* Do nothing!  But inhibit gcc warning.  */
+
+#endif /* not REGEX_MALLOC */
+
+/* Define how to allocate the failure stack.  */
+
+#if defined REL_ALLOC && defined REGEX_MALLOC
+
+# define REGEX_ALLOCATE_STACK(size)				\
+  r_alloc (&failure_stack_ptr, (size))
+# define REGEX_REALLOCATE_STACK(source, osize, nsize)		\
+  r_re_alloc (&failure_stack_ptr, (nsize))
+# define REGEX_FREE_STACK(ptr)					\
+  r_alloc_free (&failure_stack_ptr)
+
+#else /* not using relocating allocator */
+
+# ifdef REGEX_MALLOC
+
+#  define REGEX_ALLOCATE_STACK malloc
+#  define REGEX_REALLOCATE_STACK(source, osize, nsize) realloc (source, nsize)
+#  define REGEX_FREE_STACK free
+
+# else /* not REGEX_MALLOC */
+
+#  define REGEX_ALLOCATE_STACK alloca
+
+#  define REGEX_REALLOCATE_STACK(source, osize, nsize)			\
+   REGEX_REALLOCATE (source, osize, nsize)
+/* No need to explicitly free anything.  */
+#  define REGEX_FREE_STACK(arg)
+
+# endif /* not REGEX_MALLOC */
+#endif /* not using relocating allocator */
+
+
+/* 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 RETALLOC_IF(addr, n, t) \
+  if (addr) RETALLOC((addr), (n), t); else (addr) = TALLOC ((n), 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))
+
+#undef MAX
+#undef MIN
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+typedef char boolean;
+#define false 0
+#define true 1
+
+static int re_match_2_internal PARAMS ((struct re_pattern_buffer *bufp,
+					const char *string1, int size1,
+					const char *string2, int size2,
+					int pos,
+					struct re_registers *regs,
+					int stop));
+
+/* 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.  */
+
+typedef enum
 {
-  int ret;
+  no_op = 0,
+
+  /* Succeed right away--no more backtracking.  */
+  succeed,
+
+        /* Followed by one byte giving n, then by n literal bytes.  */
+  exactn,
+
+        /* 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 _RE_ARGS ((int *dest, unsigned char *source));
+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 _RE_ARGS ((int *destination,
+					       unsigned char **source));
+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)
+
+
+/* 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;
+          putchar (i - 1);
+          while (i < (1 << BYTEWIDTH)  &&  fastmap[i])
+            {
+              was_a_range = 1;
+              i++;
+            }
+	  if (was_a_range)
+            {
+              printf ("-");
+              putchar (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 *p1;
+  unsigned char *p = start;
+  unsigned char *pend = end;
+
+  if (start == NULL)
+    {
+      printf ("(null)\n");
+      return;
+    }
+
+  /* Loop over pattern commands.  */
+  while (p < pend)
+    {
+      printf ("%d:\t", p - start);
+
+      switch ((re_opcode_t) *p++)
+	{
+        case no_op:
+          printf ("/no_op");
+          break;
+
+	case exactn:
+	  mcnt = *p++;
+          printf ("/exactn/%d", mcnt);
+          do
+	    {
+              putchar ('/');
+	      putchar (*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, last = -100;
+	    register int in_range = 0;
+
+	    printf ("/charset [%s",
+	            (re_opcode_t) *(p - 1) == charset_not ? "^" : "");
+
+            assert (p + *p < pend);
+
+            for (c = 0; c < 256; c++)
+	      if (c / 8 < *p
+		  && (p[1 + (c/8)] & (1 << (c % 8))))
+		{
+		  /* Are we starting a range?  */
+		  if (last + 1 == c && ! in_range)
+		    {
+		      putchar ('-');
+		      in_range = 1;
+		    }
+		  /* Have we broken a range?  */
+		  else if (last + 1 != c && in_range)
+              {
+		      putchar (last);
+		      in_range = 0;
+		    }
+
+		  if (! in_range)
+		    putchar (c);
 
-  ret = obscure_syntax;
-  obscure_syntax = syntax;
+		  last = c;
+              }
+
+	    if (in_range)
+	      putchar (last);
+
+	    putchar (']');
+
+	    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 to %d", p + mcnt - start);
+          break;
+
+	case on_failure_keep_string_jump:
+          extract_number_and_incr (&mcnt, &p);
+  	  printf ("/on_failure_keep_string_jump to %d", p + mcnt - start);
+          break;
+
+	case dummy_failure_jump:
+          extract_number_and_incr (&mcnt, &p);
+  	  printf ("/dummy_failure_jump to %d", p + mcnt - start);
+          break;
+
+	case push_dummy_failure:
+          printf ("/push_dummy_failure");
+          break;
+
+        case maybe_pop_jump:
+          extract_number_and_incr (&mcnt, &p);
+  	  printf ("/maybe_pop_jump to %d", p + mcnt - start);
+	  break;
+
+        case pop_failure_jump:
+	  extract_number_and_incr (&mcnt, &p);
+  	  printf ("/pop_failure_jump to %d", p + mcnt - start);
+	  break;
+
+        case jump_past_alt:
+	  extract_number_and_incr (&mcnt, &p);
+  	  printf ("/jump_past_alt to %d", p + mcnt - start);
+	  break;
+
+        case jump:
+	  extract_number_and_incr (&mcnt, &p);
+  	  printf ("/jump to %d", p + mcnt - start);
+	  break;
+
+        case succeed_n:
+          extract_number_and_incr (&mcnt, &p);
+	  p1 = p + mcnt;
+          extract_number_and_incr (&mcnt2, &p);
+	  printf ("/succeed_n to %d, %d times", p1 - start, mcnt2);
+          break;
+
+        case jump_n:
+          extract_number_and_incr (&mcnt, &p);
+	  p1 = p + mcnt;
+          extract_number_and_incr (&mcnt2, &p);
+	  printf ("/jump_n to %d, %d times", p1 - start, mcnt2);
+          break;
+
+        case set_number_at:
+          extract_number_and_incr (&mcnt, &p);
+	  p1 = p + mcnt;
+          extract_number_and_incr (&mcnt2, &p);
+	  printf ("/set_number_at location %d to %d", p1 - start, 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));
+	}
+
+      putchar ('\n');
+    }
+
+  printf ("%d:\tend of pattern.\n", p - start);
+}
+
+
+void
+print_compiled_pattern (bufp)
+    struct re_pattern_buffer *bufp;
+{
+  unsigned char *buffer = bufp->buffer;
+
+  print_partial_compiled_pattern (buffer, buffer + bufp->used);
+  printf ("%ld bytes used/%ld 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: %lx\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;
+{
+  int this_char;
+
+  if (where == NULL)
+    printf ("(null)");
+  else
+    {
+      if (FIRST_STRING_P (where))
+        {
+          for (this_char = where - string1; this_char < size1; this_char++)
+            putchar (string1[this_char]);
+
+          where = string2;
+        }
+
+      for (this_char = where - string2; this_char < size2; this_char++)
+        putchar (string2[this_char]);
+    }
+}
+
+void
+printchar (c)
+     int c;
+{
+  putc (c, stderr);
+}
+
+#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.  */
+/* This has no initializer because initialized variables in Emacs
+   become read-only after dumping.  */
+reg_syntax_t re_syntax_options;
+
+
+/* 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;
+#ifdef DEBUG
+  if (syntax & RE_DEBUG)
+    debug = 1;
+  else if (debug) /* was on but now is not */
+    debug = 0;
+#endif /* DEBUG */
   return ret;
 }
+#ifdef _LIBC
+weak_alias (__re_set_syntax, re_set_syntax)
+#endif
+
+/* 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.
+   POSIX doesn't require that we do anything for REG_NOERROR,
+   but why not be nice?  */
+
+static const char *re_error_msgid[] =
+  {
+    gettext_noop ("Success"),	/* REG_NOERROR */
+    gettext_noop ("No match"),	/* REG_NOMATCH */
+    gettext_noop ("Invalid regular expression"), /* REG_BADPAT */
+    gettext_noop ("Invalid collation character"), /* REG_ECOLLATE */
+    gettext_noop ("Invalid character class name"), /* REG_ECTYPE */
+    gettext_noop ("Trailing backslash"), /* REG_EESCAPE */
+    gettext_noop ("Invalid back reference"), /* REG_ESUBREG */
+    gettext_noop ("Unmatched [ or [^"),	/* REG_EBRACK */
+    gettext_noop ("Unmatched ( or \\("), /* REG_EPAREN */
+    gettext_noop ("Unmatched \\{"), /* REG_EBRACE */
+    gettext_noop ("Invalid content of \\{\\}"), /* REG_BADBR */
+    gettext_noop ("Invalid range end"),	/* REG_ERANGE */
+    gettext_noop ("Memory exhausted"), /* REG_ESPACE */
+    gettext_noop ("Invalid preceding regular expression"), /* REG_BADRPT */
+    gettext_noop ("Premature end of regular expression"), /* REG_EEND */
+    gettext_noop ("Regular expression too big"), /* REG_ESIZE */
+    gettext_noop ("Unmatched ) or \\)"), /* REG_ERPAREN */
+  };
+
+/* Avoiding alloca during matching, to placate r_alloc.  */
+
+/* Define MATCH_MAY_ALLOCATE unless we need to make sure that the
+   searching and matching functions should not call alloca.  On some
+   systems, alloca is implemented in terms of malloc, and if we're
+   using the relocating allocator routines, then malloc could cause a
+   relocation, which might (if the strings being searched are in the
+   ralloc heap) shift the data out from underneath the regexp
+   routines.
+
+   Here's another reason to avoid allocation: Emacs
+   processes input from X in a signal handler; processing X input may
+   call malloc; if input arrives while a matching routine is calling
+   malloc, then we're scrod.  But Emacs can't just block input while
+   calling matching routines; then we don't notice interrupts when
+   they come in.  So, Emacs blocks input around all regexp calls
+   except the matching calls, which it leaves unprotected, in the
+   faith that they will not malloc.  */
+
+/* Normally, this is fine.  */
+#define MATCH_MAY_ALLOCATE
+
+/* When using GNU C, we are not REALLY using the C alloca, no matter
+   what config.h may say.  So don't take precautions for it.  */
+#ifdef __GNUC__
+# undef C_ALLOCA
+#endif
+
+/* The match routines may not allocate if (1) they would do it with malloc
+   and (2) it's not safe for them to use malloc.
+   Note that if REL_ALLOC is defined, matching would not use malloc for the
+   failure stack, but we would still use it for the register vectors;
+   so REL_ALLOC should not affect this.  */
+#if (defined C_ALLOCA || defined REGEX_MALLOC) && defined emacs
+# undef MATCH_MAY_ALLOCATE
+#endif
+
+
+/* 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_STACK.  */
+
+
+/* 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_ITEMS items each time we failed.
+   This is a variable only so users of regex can assign to it; we never
+   change it ourselves.  */
+
+#ifdef INT_IS_16BIT
+
+# if defined MATCH_MAY_ALLOCATE
+/* 4400 was enough to cause a crash on Alpha OSF/1,
+   whose default stack limit is 2mb.  */
+long int re_max_failures = 4000;
+# else
+long int re_max_failures = 2000;
+# endif
+
+union fail_stack_elt
+{
+  unsigned char *pointer;
+  long int integer;
+};
+
+typedef union fail_stack_elt fail_stack_elt_t;
+
+typedef struct
+{
+  fail_stack_elt_t *stack;
+  unsigned long int size;
+  unsigned long int avail;		/* Offset of next open position.  */
+} fail_stack_type;
+
+#else /* not INT_IS_16BIT */
+
+# if defined MATCH_MAY_ALLOCATE
+/* 4400 was enough to cause a crash on Alpha OSF/1,
+   whose default stack limit is 2mb.  */
+int re_max_failures = 20000;
+# else
+int re_max_failures = 2000;
+# endif
+
+union fail_stack_elt
+{
+  unsigned char *pointer;
+  int integer;
+};
+
+typedef union fail_stack_elt fail_stack_elt_t;
+
+typedef struct
+{
+  fail_stack_elt_t *stack;
+  unsigned size;
+  unsigned avail;			/* Offset of next open position.  */
+} fail_stack_type;
+
+#endif /* INT_IS_16BIT */
+
+#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 macros to initialize and free the failure stack.
+   Do `return -2' if the alloc fails.  */
+
+#ifdef MATCH_MAY_ALLOCATE
+# define INIT_FAIL_STACK()						\
+  do {									\
+    fail_stack.stack = (fail_stack_elt_t *)				\
+      REGEX_ALLOCATE_STACK (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)
+
+# define RESET_FAIL_STACK()  REGEX_FREE_STACK (fail_stack.stack)
+#else
+# define INIT_FAIL_STACK()						\
+  do {									\
+    fail_stack.avail = 0;						\
+  } while (0)
+
+# define RESET_FAIL_STACK()
+#endif
+
+
+/* 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_STACK requires `destination' be declared.   */
+
+#define DOUBLE_FAIL_STACK(fail_stack)					\
+  ((fail_stack).size > (unsigned) (re_max_failures * MAX_FAILURE_ITEMS)	\
+   ? 0									\
+   : ((fail_stack).stack = (fail_stack_elt_t *)				\
+        REGEX_REALLOCATE_STACK ((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 pointer POINTER 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(POINTER, FAIL_STACK)				\
+  ((FAIL_STACK_FULL ()							\
+    && !DOUBLE_FAIL_STACK (FAIL_STACK))					\
+   ? 0									\
+   : ((FAIL_STACK).stack[(FAIL_STACK).avail++].pointer = POINTER,	\
+      1))
+
+/* Push a pointer value onto the failure stack.
+   Assumes the variable `fail_stack'.  Probably should only
+   be called from within `PUSH_FAILURE_POINT'.  */
+#define PUSH_FAILURE_POINTER(item)					\
+  fail_stack.stack[fail_stack.avail++].pointer = (unsigned char *) (item)
+
+/* This pushes an integer-valued item onto the failure stack.
+   Assumes the variable `fail_stack'.  Probably should only
+   be called from within `PUSH_FAILURE_POINT'.  */
+#define PUSH_FAILURE_INT(item)					\
+  fail_stack.stack[fail_stack.avail++].integer = (item)
+
+/* Push a fail_stack_elt_t value onto the failure stack.
+   Assumes the variable `fail_stack'.  Probably should only
+   be called from within `PUSH_FAILURE_POINT'.  */
+#define PUSH_FAILURE_ELT(item)					\
+  fail_stack.stack[fail_stack.avail++] =  (item)
+
+/* These three POP... operations complement the three PUSH... operations.
+   All assume that `fail_stack' is nonempty.  */
+#define POP_FAILURE_POINTER() fail_stack.stack[--fail_stack.avail].pointer
+#define POP_FAILURE_INT() fail_stack.stack[--fail_stack.avail].integer
+#define POP_FAILURE_ELT() 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_INT
+# define DEBUG_POP(item_addr) *(item_addr) = POP_FAILURE_INT ()
+#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_pushed 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.  */				\
+    /* Can't be int, since there is not a shred of a guarantee that int	\
+       is wide enough to hold a value of something to which pointer can	\
+       be assigned */							\
+    active_reg_t 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: %ld\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");						\
+									\
+    if (1)								\
+      for (this_reg = lowest_active_reg; this_reg <= highest_active_reg; \
+	   this_reg++)							\
+	{								\
+	  DEBUG_PRINT2 ("  Pushing reg: %lu\n", this_reg);		\
+	  DEBUG_STATEMENT (num_regs_pushed++);				\
+									\
+	  DEBUG_PRINT2 ("    start: %p\n", regstart[this_reg]);		\
+	  PUSH_FAILURE_POINTER (regstart[this_reg]);			\
+									\
+	  DEBUG_PRINT2 ("    end: %p\n", regend[this_reg]);		\
+	  PUSH_FAILURE_POINTER (regend[this_reg]);			\
+									\
+	  DEBUG_PRINT2 ("    info: %p\n      ",				\
+			reg_info[this_reg].word.pointer);		\
+	  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_ELT (reg_info[this_reg].word);			\
+	}								\
+									\
+    DEBUG_PRINT2 ("  Pushing  low active reg: %ld\n", lowest_active_reg);\
+    PUSH_FAILURE_INT (lowest_active_reg);				\
+									\
+    DEBUG_PRINT2 ("  Pushing high active reg: %ld\n", highest_active_reg);\
+    PUSH_FAILURE_INT (highest_active_reg);				\
+									\
+    DEBUG_PRINT2 ("  Pushing pattern %p:\n", pattern_place);		\
+    DEBUG_PRINT_COMPILED_PATTERN (bufp, pattern_place, pend);		\
+    PUSH_FAILURE_POINTER (pattern_place);				\
+									\
+    DEBUG_PRINT2 ("  Pushing string %p: `", string_place);		\
+    DEBUG_PRINT_DOUBLE_STRING (string_place, string1, size1, string2,   \
+				 size2);				\
+    DEBUG_PRINT1 ("'\n");						\
+    PUSH_FAILURE_POINTER (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.  */
+/* We used to use (num_regs - 1), which is the number of registers
+   this regexp will save; but that was changed to 5
+   to avoid stack overflow for a regexp with lots of parens.  */
+#define MAX_FAILURE_ITEMS (5 * NUM_REG_ITEMS + NUM_NONREG_ITEMS)
+
+/* We actually push this many items.  */
+#define NUM_FAILURE_ITEMS				\
+  (((0							\
+     ? 0 : 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 (unsigned failure_id;)				\
+  active_reg_t 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_POINTER ();					\
+  if (string_temp != NULL)						\
+    str = (const char *) string_temp;					\
+									\
+  DEBUG_PRINT2 ("  Popping string %p: `", str);				\
+  DEBUG_PRINT_DOUBLE_STRING (str, string1, size1, string2, size2);	\
+  DEBUG_PRINT1 ("'\n");							\
+									\
+  pat = (unsigned char *) POP_FAILURE_POINTER ();			\
+  DEBUG_PRINT2 ("  Popping pattern %p:\n", pat);			\
+  DEBUG_PRINT_COMPILED_PATTERN (bufp, pat, pend);			\
+									\
+  /* Restore register info.  */						\
+  high_reg = (active_reg_t) POP_FAILURE_INT ();				\
+  DEBUG_PRINT2 ("  Popping high active reg: %ld\n", high_reg);		\
+									\
+  low_reg = (active_reg_t) POP_FAILURE_INT ();				\
+  DEBUG_PRINT2 ("  Popping  low active reg: %ld\n", low_reg);		\
+									\
+  if (1)								\
+    for (this_reg = high_reg; this_reg >= low_reg; this_reg--)		\
+      {									\
+	DEBUG_PRINT2 ("    Popping reg: %ld\n", this_reg);		\
+									\
+	reg_info[this_reg].word = POP_FAILURE_ELT ();			\
+	DEBUG_PRINT2 ("      info: %p\n",				\
+		      reg_info[this_reg].word.pointer);			\
+									\
+	regend[this_reg] = (const char *) POP_FAILURE_POINTER ();	\
+	DEBUG_PRINT2 ("      end: %p\n", regend[this_reg]);		\
+									\
+	regstart[this_reg] = (const char *) POP_FAILURE_POINTER ();	\
+	DEBUG_PRINT2 ("      start: %p\n", regstart[this_reg]);		\
+      }									\
+  else									\
+    {									\
+      for (this_reg = highest_active_reg; this_reg > high_reg; this_reg--) \
+	{								\
+	  reg_info[this_reg].word.integer = 0;				\
+	  regend[this_reg] = 0;						\
+	  regstart[this_reg] = 0;					\
+	}								\
+      highest_active_reg = high_reg;					\
+    }									\
+									\
+  set_regs_matched_done = 0;						\
+  DEBUG_STATEMENT (nfailure_points_popped++);				\
+} /* POP_FAILURE_POINT */
+
+
 
-/* re_compile_pattern takes a regular-expression string
-   and converts it into a buffer full of byte commands for matching.
+/* Structure for per-register (a.k.a. per-group) information.
+   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.
 
-  PATTERN   is the address of the pattern string
-  SIZE      is the length of it.
-  BUFP	    is a  struct re_pattern_buffer *  which points to the info
-	    on where to store the byte commands.
-	    This structure contains a  char *  which points to the
-	    actual space, which should have been obtained with malloc.
-	    re_compile_pattern may use  realloc  to grow the buffer space.
+   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.  */
 
-  The number of bytes of commands can be found out by looking in
-  the  struct re_pattern_buffer  that bufp pointed to,
-  after re_compile_pattern returns.
-*/
 
-#define PATPUSH(ch) (*b++ = (char) (ch))
+/* Declarations and macros for re_match_2.  */
 
-#define PATFETCH(c) \
- {if (p == pend) goto end_of_pattern; \
-  c = * (unsigned char *) p++; \
-  if (translate) c = translate[c]; }
+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									\
+    {									\
+      if (!set_regs_matched_done)					\
+	{								\
+	  active_reg_t r;						\
+	  set_regs_matched_done = 1;					\
+	  for (r = lowest_active_reg; r <= highest_active_reg; r++)	\
+	    {								\
+	      MATCHED_SOMETHING (reg_info[r])				\
+		= EVER_MATCHED_SOMETHING (reg_info[r])			\
+		= 1;							\
+	    }								\
+	}								\
+    }									\
+  while (0)
+
+/* Registers are set to a sentinel when they haven't yet matched.  */
+static char reg_unset_dummy;
+#define REG_UNSET_VALUE (&reg_unset_dummy)
+#define REG_UNSET(e) ((e) == REG_UNSET_VALUE)
+
+/* Subroutine declarations and macros for regex_compile.  */
+
+static reg_errcode_t regex_compile _RE_ARGS ((const char *pattern, size_t size,
+					      reg_syntax_t syntax,
+					      struct re_pattern_buffer *bufp));
+static void store_op1 _RE_ARGS ((re_opcode_t op, unsigned char *loc, int arg));
+static void store_op2 _RE_ARGS ((re_opcode_t op, unsigned char *loc,
+				 int arg1, int arg2));
+static void insert_op1 _RE_ARGS ((re_opcode_t op, unsigned char *loc,
+				  int arg, unsigned char *end));
+static void insert_op2 _RE_ARGS ((re_opcode_t op, unsigned char *loc,
+				  int arg1, int arg2, unsigned char *end));
+static boolean at_begline_loc_p _RE_ARGS ((const char *pattern, const char *p,
+					   reg_syntax_t syntax));
+static boolean at_endline_loc_p _RE_ARGS ((const char *p, const char *pend,
+					   reg_syntax_t syntax));
+static reg_errcode_t compile_range _RE_ARGS ((const char **p_ptr,
+					      const char *pend,
+					      char *translate,
+					      reg_syntax_t syntax,
+					      unsigned char *b));
+
+/* 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').  */
+#ifndef PATFETCH
+# define PATFETCH(c)							\
+  do {if (p == pend) return REG_EEND;					\
+    c = (unsigned char) *p++;						\
+    if (translate) c = (unsigned char) translate[c];			\
+  } while (0)
+#endif
 
-#define PATFETCH_RAW(c) \
- {if (p == pend) goto end_of_pattern; \
-  c = * (unsigned char *) p++; }
+/* 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.  */
+#ifndef TRANSLATE
+# define TRANSLATE(d) \
+  (translate ? (char) translate[(unsigned char) (d)] : (d))
+#endif
+
+
+/* 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 ((unsigned long) (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, (int) ((to) - (loc) - 3))
+
+/* Likewise, for a two-argument jump.  */
+#define STORE_JUMP2(op, loc, to, arg) \
+  store_op2 (op, loc, (int) ((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, (int) ((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, (int) ((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 (1 << 16)
-
+/* Any other compiler which, like MSC, has allocation limit below 2^16
+   bytes will have to use approach similar to what was done below for
+   MSC and drop MAX_BUF_SIZE a bit.  Otherwise you may end up
+   reallocating to 0 bytes.  Such thing is not going to work too well.
+   You have been warned!!  */
+#if defined _MSC_VER  && !defined WIN32
+/* Microsoft C 16-bit versions limit malloc to approx 65512 bytes.
+   The REALLOC define eliminates a flurry of conversion warnings,
+   but is not required. */
+# define MAX_BUF_SIZE  65500L
+# define REALLOC(p,s) realloc ((p), (size_t) (s))
+#else
+# define MAX_BUF_SIZE (1L << 16)
+# define REALLOC(p,s) realloc ((p), (s))
+#endif
 
 /* 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 {                                                                  \
-    char *old_buffer = bufp->buffer;                           \
-    if (bufp->allocated == MAX_BUF_SIZE)                                \
-      goto too_big;                                                 \
-    bufp->allocated <<= 1;                                              \
-    if (bufp->allocated > MAX_BUF_SIZE)                                 \
-      bufp->allocated = MAX_BUF_SIZE;                                   \
-    bufp->buffer = (char *) realloc (bufp->buffer, bufp->allocated);\
-    if (bufp->buffer == NULL)                                           \
-      goto memory_exhausted;                                                \
-    /* 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_jump)                                             \
-          fixup_jump = (fixup_jump - old_buffer) + bufp->buffer;\
-        if (laststart)                                                  \
-          laststart = (laststart - old_buffer) + bufp->buffer;          \
-        if (pending_exact)                                              \
-          pending_exact = (pending_exact - old_buffer) + bufp->buffer;  \
-      }                                                                 \
+#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)
 
-static void store_jump (), insert_jump ();
 
-char *
-re_compile_pattern (pattern, size, bufp)
-     char *pattern;
-     int size;
-     struct re_pattern_buffer *bufp;
-{
-  register char *b = bufp->buffer;
-  register char *p = pattern;
-  char *pend = pattern + size;
-  register unsigned c, c1;
-  char *p1;
-  unsigned char *translate = (unsigned char *) bufp->translate;
-
-  /* address of the count-byte of the most recently inserted "exactn" command.
-    This makes it possible to tell whether a new exact-match character
-    can be added to that command or requires a new "exactn" command. */
-     
-  char *pending_exact = 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
 
-  /* 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. */
+/* But patterns can have more than `MAX_REGNUM' registers.  We just
+   ignore the excess.  */
+typedef unsigned regnum_t;
 
-  char *fixup_jump = 0;
 
-  /* address of start of the most recently finished expression.
-    This tells postfix * where to find the start of its operand. */
+/* Macros for the compile stack.  */
 
-  char *laststart = 0;
+/* 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.  */
+/* int may be not enough when sizeof(int) == 2.  */
+typedef long pattern_offset_t;
 
-  /* In processing a repeat, 1 means zero matches is allowed */
+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;
 
-  char zero_times_ok;
 
-  /* In processing a repeat, 1 means many matches is allowed */
+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);						\
+         } 								\
+       } 								\
+    }
 
-  char many_times_ok;
+#if defined _LIBC || (defined HAVE_WCTYPE_H && defined HAVE_WCHAR_H)
+/* The GNU C library provides support for user-defined character classes
+   and the functions from ISO C amendement 1.  */
+# ifdef CHARCLASS_NAME_MAX
+#  define CHAR_CLASS_MAX_LENGTH CHARCLASS_NAME_MAX
+# else
+/* This shouldn't happen but some implementation might still have this
+   problem.  Use a reasonable default value.  */
+#  define CHAR_CLASS_MAX_LENGTH 256
+# endif
+
+# ifdef _LIBC
+#  define IS_CHAR_CLASS(string) __wctype (string)
+# else
+#  define IS_CHAR_CLASS(string) wctype (string)
+# endif
+#else
+# 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"))
+#endif
+
+#ifndef MATCH_MAY_ALLOCATE
+
+/* If we cannot allocate large objects within re_match_2_internal,
+   we make the fail stack and register vectors global.
+   The fail stack, we grow to the maximum size when a regexp
+   is compiled.
+   The register vectors, we adjust in size each time we
+   compile a regexp, according to the number of registers it needs.  */
+
+static fail_stack_type fail_stack;
+
+/* Size with which the following vectors are currently allocated.
+   That is so we can make them bigger as needed,
+   but never make them smaller.  */
+static int regs_allocated_size;
+
+static const char **     regstart, **     regend;
+static const char ** old_regstart, ** old_regend;
+static const char **best_regstart, **best_regend;
+static register_info_type *reg_info;
+static const char **reg_dummy;
+static register_info_type *reg_info_dummy;
+
+/* Make the register vectors big enough for NUM_REGS registers,
+   but don't make them smaller.  */
+
+static
+regex_grow_registers (num_regs)
+     int num_regs;
+{
+  if (num_regs > regs_allocated_size)
+    {
+      RETALLOC_IF (regstart,	 num_regs, const char *);
+      RETALLOC_IF (regend,	 num_regs, const char *);
+      RETALLOC_IF (old_regstart, num_regs, const char *);
+      RETALLOC_IF (old_regend,	 num_regs, const char *);
+      RETALLOC_IF (best_regstart, num_regs, const char *);
+      RETALLOC_IF (best_regend,	 num_regs, const char *);
+      RETALLOC_IF (reg_info,	 num_regs, register_info_type);
+      RETALLOC_IF (reg_dummy,	 num_regs, const char *);
+      RETALLOC_IF (reg_info_dummy, num_regs, register_info_type);
+
+      regs_allocated_size = num_regs;
+    }
+}
 
-  /* address of beginning of regexp, or inside of last \( */
+#endif /* not MATCH_MAY_ALLOCATE */
+
+static boolean group_in_compile_stack _RE_ARGS ((compile_stack_type
+						 compile_stack,
+						 regnum_t regnum));
+
+/* `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.  */
+
+/* Return, freeing storage we allocated.  */
+#define FREE_STACK_RETURN(value)		\
+  return (free (compile_stack.stack), value)
+
+static reg_errcode_t
+regex_compile (pattern, size, syntax, bufp)
+     const char *pattern;
+     size_t 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 temporary 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.  */
+  RE_TRANSLATE_TYPE 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;
 
-  char *begalt = b;
+      for (debug_count = 0; debug_count < size; debug_count++)
+        putchar (pattern[debug_count]);
+      putchar ('\n');
+    }
+#endif /* DEBUG */
 
-  /* Stack of information saved by \( and restored by \).
-     Four stack elements are pushed by each \(:
-       First, the value of b.
-       Second, the value of fixup_jump.
-       Third, the value of regnum.
-       Fourth, the value of begalt.  */
+  /* Initialize the compile stack.  */
+  compile_stack.stack = TALLOC (INIT_COMPILE_STACK_SIZE, compile_stack_elt_t);
+  if (compile_stack.stack == NULL)
+    return REG_ESPACE;
 
-  int stackb[40];
-  int *stackp = stackb;
-  int *stacke = stackb + 40;
-  int *stackt;
+  compile_stack.size = INIT_COMPILE_STACK_SIZE;
+  compile_stack.avail = 0;
 
-  /* Counts \('s as they are encountered.  Remembered for the matching \),
-     where it becomes the "register number" to put in the stop_memory command */
+  /* Initialize the pattern buffer.  */
+  bufp->syntax = syntax;
+  bufp->fastmap_accurate = 0;
+  bufp->not_bol = bufp->not_eol = 0;
 
-  int regnum = 1;
+  /* 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;
 
-  bufp->fastmap_accurate = 0;
+  /* Always count groups, whether or not bufp->no_sub is set.  */
+  bufp->re_nsub = 0;
 
-#ifndef emacs
-#ifndef SYNTAX_TABLE
-  /*
-   * Initialize the syntax table.
-   */
-   init_syntax_once();
-#endif
+#if !defined emacs && !defined SYNTAX_TABLE
+  /* Initialize the syntax table.  */
+   init_syntax_once ();
 #endif
 
   if (bufp->allocated == 0)
     {
-      bufp->allocated = 28;
       if (bufp->buffer)
-	/* EXTEND_BUFFER loses when bufp->allocated is 0 */
-	bufp->buffer = (char *) realloc (bufp->buffer, 28);
+	{ /* 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 him */
-	bufp->buffer = (char *) malloc (28);
-      if (!bufp->buffer) goto memory_exhausted;
-      begalt = b = bufp->buffer;
+        { /* Caller did not allocate a buffer.  Do it for them.  */
+          bufp->buffer = TALLOC (INIT_BUF_SIZE, unsigned char);
+        }
+      if (!bufp->buffer) FREE_STACK_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)
     {
-      if (b - bufp->buffer > bufp->allocated - 10)
-	/* Note that EXTEND_BUFFER clobbers c */
-	EXTEND_BUFFER;
-
       PATFETCH (c);
 
       switch (c)
-	{
-	case '$':
-	  if (obscure_syntax & RE_TIGHT_VBAR)
-	    {
-	      if (! (obscure_syntax & RE_CONTEXT_INDEP_OPS) && p != pend)
-		goto normal_char;
-	      /* Make operand of last vbar end before this `$'.  */
-	      if (fixup_jump)
-		store_jump (fixup_jump, jump, b);
-	      fixup_jump = 0;
-	      PATPUSH (endline);
-	      break;
-	    }
-
-	  /* $ means succeed if at end of line, but only in special contexts.
-	    If randomly in the middle of a pattern, it is a normal character. */
-	  if (p == pend || *p == '\n'
-	      || (obscure_syntax & RE_CONTEXT_INDEP_OPS)
-	      || (obscure_syntax & RE_NO_BK_PARENS
-		  ? *p == ')'
-		  : *p == '\\' && p[1] == ')')
-	      || (obscure_syntax & RE_NO_BK_VBAR
-		  ? *p == '|'
-		  : *p == '\\' && p[1] == '|'))
-	    {
-	      PATPUSH (endline);
-	      break;
-	    }
-	  goto normal_char;
+        {
+        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 '^':
-	  /* ^ means succeed if at beg of line, but only if no preceding pattern. */
-
-	  if (laststart && p[-2] != '\n'
-	      && ! (obscure_syntax & RE_CONTEXT_INDEP_OPS))
-	    goto normal_char;
-	  if (obscure_syntax & RE_TIGHT_VBAR)
-	    {
-	      if (p != pattern + 1
-		  && ! (obscure_syntax & RE_CONTEXT_INDEP_OPS))
-		goto normal_char;
-	      PATPUSH (begline);
-	      begalt = b;
-	    }
-	  else
-	    PATPUSH (begline);
-	  break;
 
 	case '+':
-	case '?':
-	  if (obscure_syntax & RE_BK_PLUS_QM)
-	    goto normal_char;
-	handle_plus:
-	case '*':
-	  /* If there is no previous pattern, char not special. */
-	  if (!laststart && ! (obscure_syntax & RE_CONTEXT_INDEP_OPS))
-	    goto normal_char;
-	  /* If there is a sequence of repetition chars,
-	     collapse it down to equivalent to just one.  */
-	  zero_times_ok = 0;
-	  many_times_ok = 0;
-	  while (1)
-	    {
-	      zero_times_ok |= c != '+';
-	      many_times_ok |= c != '?';
-	      if (p == pend)
-		break;
-	      PATFETCH (c);
-	      if (c == '*')
-		;
-	      else if (!(obscure_syntax & RE_BK_PLUS_QM)
-		       && (c == '+' || c == '?'))
-		;
-	      else if ((obscure_syntax & RE_BK_PLUS_QM)
-		       && c == '\\')
-		{
-		  int c1;
-		  PATFETCH (c1);
-		  if (!(c1 == '+' || c1 == '?'))
-		    {
-		      PATUNFETCH;
-		      PATUNFETCH;
-		      break;
-		    }
-		  c = c1;
-		}
-	      else
-		{
-		  PATUNFETCH;
-		  break;
-		}
-	    }
-
-	  /* Star, etc. applied to an empty pattern is equivalent
-	     to an empty pattern.  */
-	  if (!laststart)
-	    break;
-
-	  /* Now we know whether 0 matches is allowed,
-	     and whether 2 or more matches is allowed.  */
-	  if (many_times_ok)
-	    {
-	      /* If more than one repetition is allowed,
-		 put in a backward jump at the end.  */
-	      store_jump (b, maybe_finalize_jump, laststart - 3);
-	      b += 3;
-	    }
-	  insert_jump (on_failure_jump, laststart, b + 3, b);
-	  pending_exact = 0;
-	  b += 3;
-	  if (!zero_times_ok)
-	    {
-	      /* At least one repetition required: insert before the loop
-		 a skip over the initial on-failure-jump instruction */
-	      insert_jump (dummy_failure_jump, laststart, laststart + 6, b);
-	      b += 3;
-	    }
+        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)
+                FREE_STACK_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) FREE_STACK_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;
-	  PATPUSH (anychar);
-	  break;
+          laststart = b;
+          BUF_PUSH (anychar);
+          break;
+
+
+        case '[':
+          {
+            boolean had_char_class = false;
+
+            if (p == pend) FREE_STACK_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) FREE_STACK_RETURN (REG_EBRACK);
+
+                PATFETCH (c);
+
+                /* \ might escape characters inside [...] and [^...].  */
+                if ((syntax & RE_BACKSLASH_ESCAPE_IN_LISTS) && c == '\\')
+                  {
+                    if (p == pend) FREE_STACK_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 != ']')
+                  FREE_STACK_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) FREE_STACK_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) FREE_STACK_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) FREE_STACK_RETURN (REG_EBRACK);
+
+                    for (;;)
+                      {
+                        PATFETCH (c);
+                        if ((c == ':' && *p == ']') || 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 == ']')
+                      {
+#if defined _LIBC || (defined HAVE_WCTYPE_H && defined HAVE_WCHAR_H)
+                        boolean is_lower = STREQ (str, "lower");
+                        boolean is_upper = STREQ (str, "upper");
+			wctype_t wt;
+                        int ch;
+
+			wt = IS_CHAR_CLASS (str);
+			if (wt == 0)
+			  FREE_STACK_RETURN (REG_ECTYPE);
+
+                        /* Throw away the ] at the end of the character
+                           class.  */
+                        PATFETCH (c);
+
+                        if (p == pend) FREE_STACK_RETURN (REG_EBRACK);
+
+                        for (ch = 0; ch < 1 << BYTEWIDTH; ++ch)
+			  {
+# ifdef _LIBC
+			    if (__iswctype (__btowc (ch), wt))
+			      SET_LIST_BIT (ch);
+#else
+			    if (iswctype (btowc (ch), wt))
+			      SET_LIST_BIT (ch);
+#endif
 
-	case '[':
-	  while (b - bufp->buffer
-		 > bufp->allocated - 3 - (1 << BYTEWIDTH) / BYTEWIDTH)
-	    /* Note that EXTEND_BUFFER clobbers c */
-	    EXTEND_BUFFER;
+			    if (translate && (is_upper || is_lower)
+				&& (ISUPPER (ch) || ISLOWER (ch)))
+			      SET_LIST_BIT (ch);
+			  }
+
+                        had_char_class = true;
+#else
+                        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))
+			  FREE_STACK_RETURN (REG_ECTYPE);
+
+                        /* Throw away the ] at the end of the character
+                           class.  */
+                        PATFETCH (c);
+
+                        if (p == pend) FREE_STACK_RETURN (REG_EBRACK);
+
+                        for (ch = 0; ch < 1 << BYTEWIDTH; ch++)
+                          {
+			    /* This was split into 3 if's to
+			       avoid an arbitrary limit in some compiler.  */
+                            if (   (is_alnum  && ISALNUM (ch))
+                                || (is_alpha  && ISALPHA (ch))
+                                || (is_blank  && ISBLANK (ch))
+                                || (is_cntrl  && ISCNTRL (ch)))
+			      SET_LIST_BIT (ch);
+			    if (   (is_digit  && ISDIGIT (ch))
+                                || (is_graph  && ISGRAPH (ch))
+                                || (is_lower  && ISLOWER (ch))
+                                || (is_print  && ISPRINT (ch)))
+			      SET_LIST_BIT (ch);
+			    if (   (is_punct  && ISPUNCT (ch))
+                                || (is_space  && ISSPACE (ch))
+                                || (is_upper  && ISUPPER (ch))
+                                || (is_xdigit && ISXDIGIT (ch)))
+			      SET_LIST_BIT (ch);
+			    if (   translate && (is_upper || is_lower)
+				&& (ISUPPER (ch) || ISLOWER (ch)))
+			      SET_LIST_BIT (ch);
+                          }
+                        had_char_class = true;
+#endif	/* libc || wctype.h */
+                      }
+                    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;
 
-	  laststart = b;
-	  if (*p == '^')
-	    PATPUSH (charset_not), p++;
-	  else
-	    PATPUSH (charset);
-	  p1 = p;
-
-	  PATPUSH ((1 << BYTEWIDTH) / BYTEWIDTH);
-	  /* Clear the whole map */
-	  memset (b, '\0', (1 << BYTEWIDTH) / BYTEWIDTH);
-	  /* Read in characters and ranges, setting map bits */
-	  while (1)
-	    {
-	      PATFETCH (c);
-	      if (c == ']' && p != p1 + 1) break;
-	      if (*p == '-' && p[1] != ']')
-		{
-		  PATFETCH (c1);
-		  PATFETCH (c1);
-		  while (c <= c1)
-		    b[c / BYTEWIDTH] |= 1 << (c % BYTEWIDTH), c++;
-		}
-	      else
-		{
-		  b[c / BYTEWIDTH] |= 1 << (c % BYTEWIDTH);
-		}
-	    }
-	  /* Discard any bitmap bytes that are all 0 at the end of the map.
-	     Decrement the map-length byte too. */
-	  while ((int) b[-1] > 0 && b[b[-1] - 1] == 0)
-	    b[-1]--;
-	  b += b[-1];
-	  break;
 
 	case '(':
-	  if (! (obscure_syntax & RE_NO_BK_PARENS))
-	    goto normal_char;
-	  else
-	    goto handle_open;
+          if (syntax & RE_NO_BK_PARENS)
+            goto handle_open;
+          else
+            goto normal_char;
 
-	case ')':
-	  if (! (obscure_syntax & RE_NO_BK_PARENS))
-	    goto normal_char;
-	  else
-	    goto handle_close;
 
-	case '\n':
-	  if (! (obscure_syntax & RE_NEWLINE_OR))
-	    goto normal_char;
-	  else
-	    goto handle_bar;
+        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 (! (obscure_syntax & RE_NO_BK_VBAR))
-	    goto normal_char;
-	  else
-	    goto handle_bar;
+          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) goto invalid_pattern;
-	  PATFETCH_RAW (c);
-	  switch (c)
-	    {
-	    case '(':
-	      if (obscure_syntax & RE_NO_BK_PARENS)
-		goto normal_backsl;
-	    handle_open:
-	      if (stackp == stacke) goto nesting_too_deep;
-	      if (regnum < RE_NREGS)
-	        {
-		  PATPUSH (start_memory);
-		  PATPUSH (regnum);
-	        }
-	      *stackp++ = b - bufp->buffer;
-	      *stackp++ = fixup_jump ? fixup_jump - bufp->buffer + 1 : 0;
-	      *stackp++ = regnum++;
-	      *stackp++ = begalt - bufp->buffer;
-	      fixup_jump = 0;
-	      laststart = 0;
-	      begalt = b;
-	      break;
-
-	    case ')':
-	      if (obscure_syntax & RE_NO_BK_PARENS)
-		goto normal_backsl;
-	    handle_close:
-	      if (stackp == stackb) goto unmatched_close;
-	      begalt = *--stackp + bufp->buffer;
-	      if (fixup_jump)
-		store_jump (fixup_jump, jump, b);
-	      if (stackp[-1] < RE_NREGS)
+          if (p == pend) FREE_STACK_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)
 		{
-		  PATPUSH (stop_memory);
-		  PATPUSH (stackp[-1]);
+		  if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
+		    goto normal_backslash;
+		  else
+		    FREE_STACK_RETURN (REG_ERPAREN);
 		}
-	      stackp -= 2;
-	      fixup_jump = 0;
-	      if (*stackp)
-		fixup_jump = *stackp + bufp->buffer - 1;
-	      laststart = *--stackp + bufp->buffer;
-	      break;
-
-	    case '|':
-	      if (obscure_syntax & RE_NO_BK_VBAR)
-		goto normal_backsl;
-	    handle_bar:
-	      insert_jump (on_failure_jump, begalt, b + 6, b);
-	      pending_exact = 0;
-	      b += 3;
-	      if (fixup_jump)
-		store_jump (fixup_jump, jump, b);
-	      fixup_jump = b;
-	      b += 3;
-	      laststart = 0;
-	      begalt = b;
-	      break;
+
+            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
+		    FREE_STACK_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
+                      FREE_STACK_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
+                      FREE_STACK_RETURN (REG_BADBR);
+                  }
+
+                if (!(syntax & RE_NO_BK_BRACES))
+                  {
+                    if (c != '\\') FREE_STACK_RETURN (REG_EBRACE);
+
+                    PATFETCH (c);
+                  }
+
+                if (c != '}')
+                  {
+                    if (syntax & RE_NO_BK_BRACES)
+                      goto unfetch_interval;
+                    else
+                      FREE_STACK_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)
+                      FREE_STACK_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> <succeed_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
-	    case '=':
-	      PATPUSH (at_dot);
-	      break;
-
-	    case 's':	
-	      laststart = b;
-	      PATPUSH (syntaxspec);
-	      PATFETCH (c);
-	      PATPUSH (syntax_spec_code[c]);
-	      break;
-
-	    case 'S':
-	      laststart = b;
-	      PATPUSH (notsyntaxspec);
-	      PATFETCH (c);
-	      PATPUSH (syntax_spec_code[c]);
-	      break;
+            /* 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;
-	      PATPUSH (wordchar);
-	      break;
-
-	    case 'W':
-	      laststart = b;
-	      PATPUSH (notwordchar);
-	      break;
-
-	    case '<':
-	      PATPUSH (wordbeg);
-	      break;
-
-	    case '>':
-	      PATPUSH (wordend);
-	      break;
-
-	    case 'b':
-	      PATPUSH (wordbound);
-	      break;
-
-	    case 'B':
-	      PATPUSH (notwordbound);
-	      break;
-
-	    case '`':
-	      PATPUSH (begbuf);
-	      break;
-
-	    case '\'':
-	      PATPUSH (endbuf);
-	      break;
-
-	    case '1':
-	    case '2':
-	    case '3':
-	    case '4':
-	    case '5':
-	    case '6':
-	    case '7':
-	    case '8':
-	    case '9':
-	      c1 = c - '0';
-	      if (c1 >= regnum)
+
+            case 'w':
+	      if (syntax & RE_NO_GNU_OPS)
 		goto normal_char;
-	      for (stackt = stackp - 2;  stackt > stackb;  stackt -= 4)
- 		if (*stackt == c1)
-		  goto normal_char;
-	      laststart = b;
-	      PATPUSH (duplicate);
-	      PATPUSH (c1);
-	      break;
-
-	    case '+':
-	    case '?':
-	      if (obscure_syntax & RE_BK_PLUS_QM)
-		goto handle_plus;
-
-	    default:
-	    normal_backsl:
-	      /* 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.  */
-	      if (translate) c = translate[c];
-	      goto normal_char;
-	    }
-	  break;
+              laststart = b;
+              BUF_PUSH (wordchar);
+              break;
+
+
+            case 'W':
+	      if (syntax & RE_NO_GNU_OPS)
+		goto normal_char;
+              laststart = b;
+              BUF_PUSH (notwordchar);
+              break;
+
+
+            case '<':
+	      if (syntax & RE_NO_GNU_OPS)
+		goto normal_char;
+              BUF_PUSH (wordbeg);
+              break;
+
+            case '>':
+	      if (syntax & RE_NO_GNU_OPS)
+		goto normal_char;
+              BUF_PUSH (wordend);
+              break;
+
+            case 'b':
+	      if (syntax & RE_NO_GNU_OPS)
+		goto normal_char;
+              BUF_PUSH (wordbound);
+              break;
+
+            case 'B':
+	      if (syntax & RE_NO_GNU_OPS)
+		goto normal_char;
+              BUF_PUSH (notwordbound);
+              break;
+
+            case '`':
+	      if (syntax & RE_NO_GNU_OPS)
+		goto normal_char;
+              BUF_PUSH (begbuf);
+              break;
+
+            case '\'':
+	      if (syntax & RE_NO_GNU_OPS)
+		goto normal_char;
+              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)
+                FREE_STACK_RETURN (REG_ESUBREG);
+
+              /* Can't back reference to a subexpression if inside of it.  */
+              if (group_in_compile_stack (compile_stack, (regnum_t) 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 (!pending_exact || pending_exact + *pending_exact + 1 != b
-	      || *pending_exact == 0177 || *p == '*' || *p == '^'
-	      || ((obscure_syntax & RE_BK_PLUS_QM)
+	      /* 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 == '?')))
+		  : (*p == '+' || *p == '?'))
+	      || ((syntax & RE_INTERVALS)
+                  && ((syntax & RE_NO_BK_BRACES)
+		      ? *p == '{'
+                      : (p[0] == '\\' && p[1] == '{'))))
 	    {
-	      laststart = b;
-	      PATPUSH (exactn);
-	      pending_exact = b;
-	      PATPUSH (0);
-	    }
-	  PATPUSH (c);
-	  (*pending_exact)++;
-	}
-    }
+	      /* Start building a new exactn.  */
 
-  if (fixup_jump)
-    store_jump (fixup_jump, jump, b);
+              laststart = b;
 
-  if (stackp != stackb) goto unmatched_open;
+	      BUF_PUSH_2 (exactn, 0);
+	      pending_exact = b - 1;
+            }
 
-  bufp->used = b - bufp->buffer;
-  return 0;
+	  BUF_PUSH (c);
+          (*pending_exact)++;
+	  break;
+        } /* switch (c) */
+    } /* while p != pend */
 
- invalid_pattern:
-  return "Invalid regular expression";
 
- unmatched_open:
-  return "Unmatched \\(";
+  /* Through the pattern now.  */
 
- unmatched_close:
-  return "Unmatched \\)";
+  if (fixup_alt_jump)
+    STORE_JUMP (jump_past_alt, fixup_alt_jump, b);
 
- end_of_pattern:
-  return "Premature end of regular expression";
+  if (!COMPILE_STACK_EMPTY)
+    FREE_STACK_RETURN (REG_EPAREN);
 
- nesting_too_deep:
-  return "Nesting too deep";
+  /* If we don't want backtracking, force success
+     the first time we reach the end of the compiled pattern.  */
+  if (syntax & RE_NO_POSIX_BACKTRACKING)
+    BUF_PUSH (succeed);
 
- too_big:
-  return "Regular expression too big";
+  free (compile_stack.stack);
 
- memory_exhausted:
-  return "Memory exhausted";
+  /* We have succeeded; set the length of the buffer.  */
+  bufp->used = b - bufp->buffer;
+
+#ifdef DEBUG
+  if (debug)
+    {
+      DEBUG_PRINT1 ("\nCompiled pattern: \n");
+      print_compiled_pattern (bufp);
+    }
+#endif /* DEBUG */
+
+#ifndef MATCH_MAY_ALLOCATE
+  /* Initialize the failure stack to the largest possible stack.  This
+     isn't necessary unless we're trying to avoid calling alloca in
+     the search and match routines.  */
+  {
+    int num_regs = bufp->re_nsub + 1;
+
+    /* Since DOUBLE_FAIL_STACK refuses to double only if the current size
+       is strictly greater than re_max_failures, the largest possible stack
+       is 2 * re_max_failures failure points.  */
+    if (fail_stack.size < (2 * re_max_failures * MAX_FAILURE_ITEMS))
+      {
+	fail_stack.size = (2 * re_max_failures * MAX_FAILURE_ITEMS);
+
+# ifdef emacs
+	if (! fail_stack.stack)
+	  fail_stack.stack
+	    = (fail_stack_elt_t *) xmalloc (fail_stack.size
+					    * sizeof (fail_stack_elt_t));
+	else
+	  fail_stack.stack
+	    = (fail_stack_elt_t *) xrealloc (fail_stack.stack,
+					     (fail_stack.size
+					      * sizeof (fail_stack_elt_t)));
+# else /* not emacs */
+	if (! fail_stack.stack)
+	  fail_stack.stack
+	    = (fail_stack_elt_t *) malloc (fail_stack.size
+					   * sizeof (fail_stack_elt_t));
+	else
+	  fail_stack.stack
+	    = (fail_stack_elt_t *) realloc (fail_stack.stack,
+					    (fail_stack.size
+					     * sizeof (fail_stack_elt_t)));
+# endif /* not emacs */
+      }
+
+    regex_grow_registers (num_regs);
+  }
+#endif /* not MATCH_MAY_ALLOCATE */
+
+  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);
 }
 
-/* Store where `from' points a jump operation to jump to where `to' points.
-  `opcode' is the opcode to store. */
+
+/* Like `store_op1', but for two two-byte parameters ARG1 and ARG2.  */
 
 static void
-store_jump (from, opcode, to)
-     char *from, *to;
-     char opcode;
+store_op2 (op, loc, arg1, arg2)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg1, arg2;
 {
-  from[0] = opcode;
-  from[1] = (to - (from + 3)) & 0377;
-  from[2] = (to - (from + 3)) >> 8;
+  *loc = (unsigned char) op;
+  STORE_NUMBER (loc + 1, arg1);
+  STORE_NUMBER (loc + 3, arg2);
 }
 
-/* Open up space at char FROM, and insert there a jump to TO.
-   CURRENT_END gives te end of the storage no in use,
-   so we know how much data to copy up.
-   OP is the opcode of the jump to insert.
 
-   If you call this function, you must zero out pending_exact.  */
+/* 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_jump (op, from, to, current_end)
-     char op;
-     char *from, *to, *current_end;
+insert_op1 (op, loc, arg, end)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg;
+    unsigned char *end;
 {
-  register char *pto = current_end + 3;
-  register char *pfrom = current_end;
-  while (pfrom != from)
+  register unsigned char *pfrom = end;
+  register unsigned char *pto = end + 3;
+
+  while (pfrom != loc)
     *--pto = *--pfrom;
-  store_jump (from, op, to);
+
+  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;
+    reg_syntax_t syntax;
+{
+  const char *next = p;
+  boolean next_backslash = *next == '\\';
+  const char *next_next = p + 1 < pend ? p + 1 : 0;
+
+  return
+       /* Before a subexpression?  */
+       (syntax & RE_NO_BK_PARENS ? *next == ')'
+        : next_backslash && next_next && *next_next == ')')
+       /* Before an alternative?  */
+    || (syntax & RE_NO_BK_VBAR ? *next == '|'
+        : next_backslash && next_next && *next_next == '|');
+}
+
+
+/* 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;
+    RE_TRANSLATE_TYPE translate;
+    reg_syntax_t syntax;
+    unsigned char *b;
+{
+  unsigned this_char;
+
+  const char *p = *p_ptr;
+  unsigned 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.  */
+  /* The SVR4 compiler on the 3B2 had trouble with unsigned const char *.  */
+  range_start = ((const unsigned char *) p)[-2];
+  range_end   = ((const 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;
 }
 
-/* Given a pattern, compute a fastmap from it.
- The 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 totally implausible text.
+/* 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.
- The other components of bufp describe the pattern to be used.  */
+   The caller must supply the address of a (1 << BYTEWIDTH)-byte data
+   area as BUFP->fastmap.
 
-void
+   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;
 {
-  unsigned char *pattern = (unsigned char *) bufp->buffer;
-  int size = bufp->used;
+  int j, k;
+#ifdef MATCH_MAY_ALLOCATE
+  fail_stack_type fail_stack;
+#endif
+#ifndef REGEX_MALLOC
+  char *destination;
+#endif
+
   register char *fastmap = bufp->fastmap;
-  register unsigned char *p = pattern;
-  register unsigned char *pend = pattern + size;
-  register int j;
-  unsigned char *translate = (unsigned char *) bufp->translate;
+  unsigned char *pattern = bufp->buffer;
+  unsigned char *p = pattern;
+  register unsigned char *pend = pattern + bufp->used;
+
+#ifdef REL_ALLOC
+  /* This holds the pointer to the failure stack, when
+     it is allocated relocatably.  */
+  fail_stack_elt_t *failure_stack_ptr;
+#endif
+
+  /* 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;
 
-  unsigned char *stackb[NFAILURES];
-  unsigned char **stackp = stackb;
+  assert (fastmap != NULL && p != NULL);
 
-  memset (fastmap, '\0', (1 << BYTEWIDTH));
-  bufp->fastmap_accurate = 1;
+  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)
+
+  while (1)
     {
-      if (p == pend)
+      if (p == pend || *p == succeed)
 	{
-	  bufp->can_be_null = 1;
-	  break;
+	  /* We have reached the (effective) end of pattern.  */
+	  if (!FAIL_STACK_EMPTY ())
+	    {
+	      bufp->can_be_null |= path_can_be_null;
+
+	      /* Reset for next path.  */
+	      path_can_be_null = true;
+
+	      p = fail_stack.stack[--fail_stack.avail].pointer;
+
+	      continue;
+	    }
+	  else
+	    break;
 	}
-#ifdef SWITCH_ENUM_BUG
-      switch ((int) ((enum regexpcode) *p++))
-#else
-      switch ((enum regexpcode) *p++)
-#endif
+
+      /* We should never be about to go beyond the end of the pattern.  */
+      assert (p < pend);
+
+      switch (SWITCH_ENUM_CAST ((re_opcode_t) *p++))
 	{
+
+        /* 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;
+          goto done;
+
+
+      /* Following are the cases which match a character.  These end
+         with `break'.  */
+
 	case exactn:
-	  if (translate)
-	    fastmap[translate[p[1]]] = 1;
-	  else
-	    fastmap[p[1]] = 1;
+          fastmap[p[1]] = 1;
 	  break;
 
-        case begline:
-        case before_dot:
-	case at_dot:
-	case after_dot:
-	case begbuf:
-	case endbuf:
-	case wordbound:
-	case notwordbound:
-	case wordbeg:
-	case wordend:
-	  continue;
 
-	case endline:
-	  if (translate)
-	    fastmap[translate['\n']] = 1;
-	  else
-	    fastmap['\n'] = 1;
-	  if (bufp->can_be_null != 1)
-	    bufp->can_be_null = 2;
+        case charset:
+          for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
+	    if (p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH)))
+              fastmap[j] = 1;
 	  break;
 
-	case finalize_jump:
-	case maybe_finalize_jump:
-	case jump:
-	case dummy_failure_jump:
-	  bufp->can_be_null = 1;
-	  j = *p++ & 0377;
-	  j += SIGN_EXTEND_CHAR (*(char *)p) << 8;
-	  p += j + 1;		/* The 1 compensates for missing ++ above */
-	  if (j > 0)
-	    continue;
-	  /* Jump backward reached implies we just went through
-	     the body of a loop and matched nothing.
-	     Opcode jumped to should be an on_failure_jump.
-	     Just treat it like an ordinary jump.
-	     For a * loop, it has pushed its failure point already;
-	     if so, discard that as redundant.  */
-	  if ((enum regexpcode) *p != on_failure_jump)
-	    continue;
-	  p++;
-	  j = *p++ & 0377;
-	  j += SIGN_EXTEND_CHAR (*(char *)p) << 8;
-	  p += j + 1;		/* The 1 compensates for missing ++ above */
-	  if (stackp != stackb && *stackp == p)
-	    stackp--;
-	  continue;
-	  
-	case on_failure_jump:
-	  j = *p++ & 0377;
-	  j += SIGN_EXTEND_CHAR (*(char *)p) << 8;
-	  p++;
-	  *++stackp = p + j;
-	  continue;
 
-	case start_memory:
-	case stop_memory:
-	  p++;
-	  continue;
+	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 duplicate:
-	  bufp->can_be_null = 1;
-	  fastmap['\n'] = 1;
-	case anychar:
-	  for (j = 0; j < (1 << BYTEWIDTH); j++)
-	    if (j != '\n')
-	      fastmap[j] = 1;
-	  if (bufp->can_be_null)
-	    return;
-	  /* Don't return; check the alternative paths
-	     so we can set can_be_null if appropriate.  */
-	  break;
 
 	case wordchar:
 	  for (j = 0; j < (1 << BYTEWIDTH); j++)
@@ -828,120 +3227,302 @@ re_compile_fastmap (bufp)
 	      fastmap[j] = 1;
 	  break;
 
+
 	case notwordchar:
 	  for (j = 0; j < (1 << BYTEWIDTH); j++)
 	    if (SYNTAX (j) != Sword)
 	      fastmap[j] = 1;
 	  break;
 
+
+        case anychar:
+	  {
+	    int fastmap_newline = fastmap['\n'];
+
+	    /* `.' matches anything ...  */
+	    for (j = 0; j < (1 << BYTEWIDTH); j++)
+	      fastmap[j] = 1;
+
+	    /* ... except perhaps newline.  */
+	    if (!(bufp->syntax & RE_DOT_NEWLINE))
+	      fastmap['\n'] = fastmap_newline;
+
+	    /* 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)
+	      goto done;
+
+	    /* Otherwise, have to check alternative paths.  */
+	    break;
+	  }
+
 #ifdef emacs
-	case syntaxspec:
+        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 /* emacs */
 
-	case charset:
-	  for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
-	    if (p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH)))
-	      {
-		if (translate)
-		  fastmap[translate[j]] = 1;
-		else
-		  fastmap[j] = 1;
-	      }
-	  break;
 
-	case charset_not:
-	  /* Chars beyond end of map must be allowed */
-	  for (j = *p * BYTEWIDTH; j < (1 << BYTEWIDTH); j++)
-	    if (translate)
-	      fastmap[translate[j]] = 1;
-	    else
-	      fastmap[j] = 1;
+        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].pointer == 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))
+		{
+		  RESET_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;
+
 
-	  for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
-	    if (!(p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH))))
-	      {
-		if (translate)
-		  fastmap[translate[j]] = 1;
-		else
-		  fastmap[j] = 1;
-	      }
-	  break;
-	case unused:
-	case syntaxspec:
-	case notsyntaxspec:
 	default:
-	  break;
-	}
+          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;
+
+ done:
+  RESET_FAIL_STACK ();
+  return 0;
+} /* re_compile_fastmap */
+#ifdef _LIBC
+weak_alias (__re_compile_fastmap, re_compile_fastmap)
+#endif
+
+/* 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.
 
-      /* Get here means we have successfully found the possible starting characters
-	 of one path of the pattern.  We need not follow this path any farther.
-	 Instead, look at the next alternative remembered in the stack. */
-      if (stackp != stackb)
-	p = *stackp--;
-      else
-	break;
+   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;
     }
 }
+#ifdef _LIBC
+weak_alias (__re_set_registers, re_set_registers)
+#endif
 
-/* Like re_search_2, below, but only one string is specified. */
+/* 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 (pbufp, string, size, startpos, range, regs)
-     struct re_pattern_buffer *pbufp;
-     char *string;
+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 (pbufp, 0, 0, string, size, startpos, range, regs, size);
+  return re_search_2 (bufp, NULL, 0, string, size, startpos, range,
+		      regs, size);
 }
+#ifdef _LIBC
+weak_alias (__re_search, re_search)
+#endif
 
-/* Like re_match_2 but tries first a match starting at index STARTPOS,
-   then at STARTPOS + 1, and so on.
-   RANGE is the number of places to try before giving up.
-   If RANGE is negative, the starting positions tried are
-    STARTPOS, STARTPOS - 1, etc.
-   It is up to the caller to make sure that range is not so large
-   as to take the starting position outside of the input strings.
 
-The value returned is the position at which the match was found,
- or -1 if no match was found,
- or -2 if error (such as failure stack overflow).  */
+/* 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 (pbufp, string1, size1, string2, size2, startpos, range, regs, mstop)
-     struct re_pattern_buffer *pbufp;
-     char *string1, *string2;
+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;
-     register int range;
+     int range;
      struct re_registers *regs;
-     int mstop;
+     int stop;
 {
-  register char *fastmap = pbufp->fastmap;
-  register unsigned char *translate = (unsigned char *) pbufp->translate;
-  int total = size1 + size2;
   int val;
-
-  /* Update the fastmap now if not correct already */
-  if (fastmap && !pbufp->fastmap_accurate)
-    re_compile_fastmap (pbufp);
-  
-  /* Don't waste time in a long search for a pattern
-     that says it is anchored.  */
-  if (pbufp->used > 0 && (enum regexpcode) pbufp->buffer[0] == begbuf
-      && range > 0)
+  register char *fastmap = bufp->fastmap;
+  register RE_TRANSLATE_TYPE 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.
+     Make sure we won't move STARTPOS below 0 or above TOTAL_SIZE.  */
+  if (endpos < 0)
+    range = 0 - 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;
@@ -949,159 +3530,451 @@ re_search_2 (pbufp, string1, size1, string2, size2, startpos, range, regs, mstop
 	range = 1;
     }
 
-  while (1)
+#ifdef emacs
+  /* In a forward search for something that starts with \=.
+     don't keep searching past point.  */
+  if (bufp->used > 0 && (re_opcode_t) bufp->buffer[0] == at_dot && range > 0)
     {
-      /* If a fastmap is supplied, skip quickly over characters
-	 that cannot possibly be the start of a match.
-	 Note, however, that if the pattern can possibly match
-	 the null string, we must test it at each starting point
-	 so that we take the first null string we get.  */
+      range = PT - startpos;
+      if (range <= 0)
+	return -1;
+    }
+#endif /* emacs */
+
+  /* Update the fastmap now if not correct already.  */
+  if (fastmap && !bufp->fastmap_accurate)
+    if (re_compile_fastmap (bufp) == -2)
+      return -2;
 
-      if (fastmap && startpos < total && pbufp->can_be_null != 1)
+  /* 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)
+	  if (range > 0)	/* Searching forwards.  */
 	    {
+	      register const char *d;
 	      register int lim = 0;
-	      register unsigned char *p;
 	      int irange = range;
-	      if (startpos < size1 && startpos + range >= size1)
-		lim = range - (size1 - startpos);
 
-	      p = ((unsigned char *)
-		   &(startpos >= size1 ? string2 - size1 : string1)[startpos]);
+              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[translate[*p++]])
-		    range--;
-		}
+                while (range > lim
+                       && !fastmap[(unsigned char)
+				   translate[(unsigned char) *d++]])
+                  range--;
 	      else
-		{
-		  while (range > lim && !fastmap[*p++])
-		    range--;
-		}
+                while (range > lim && !fastmap[(unsigned char) *d++])
+                  range--;
+
 	      startpos += irange - range;
 	    }
-	  else
+	  else				/* Searching backwards.  */
 	    {
-	      register unsigned char c;
-	      if (startpos >= size1)
-		c = string2[startpos - size1];
-	      else
-		c = string1[startpos];
-	      c &= 0xff;
-	      if (translate ? !fastmap[translate[c]] : !fastmap[c])
+	      register char c = (size1 == 0 || startpos >= size1
+                                 ? string2[startpos - size1]
+                                 : string1[startpos]);
+
+	      if (!fastmap[(unsigned char) TRANSLATE (c)])
 		goto advance;
 	    }
 	}
 
-      if (range >= 0 && startpos == total
-	  && fastmap && pbufp->can_be_null == 0)
+      /* 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 (pbufp, string1, size1, string2, size2, startpos, regs, mstop);
-      if (0 <= val)
-	{
-	  if (val == -2)
-	    return -2;
-	  return startpos;
-	}
-
-#ifdef C_ALLOCA
+      val = re_match_2_internal (bufp, string1, size1, string2, size2,
+				 startpos, regs, stop);
+#ifndef REGEX_MALLOC
+# ifdef C_ALLOCA
       alloca (0);
-#endif /* C_ALLOCA */
+# endif
+#endif
+
+      if (val >= 0)
+	return startpos;
+
+      if (val == -2)
+	return -2;
 
     advance:
-      if (!range) break;
-      if (range > 0) range--, startpos++; else range++, startpos--;
+      if (!range)
+        break;
+      else if (range > 0)
+        {
+          range--;
+          startpos++;
+        }
+      else
+        {
+          range++;
+          startpos--;
+        }
     }
   return -1;
-}
+} /* re_search_2 */
+#ifdef _LIBC
+weak_alias (__re_search_2, re_search_2)
+#endif
 
-#ifndef emacs   /* emacs never uses this */
-int
-re_match (pbufp, string, size, pos, regs)
-     struct re_pattern_buffer *pbufp;
-     char *string;
-     int size, pos;
-     struct re_registers *regs;
-{
-  return re_match_2 (pbufp, 0, 0, string, size, pos, regs, size);
-}
-#endif /* emacs */
+/* 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)				\
+   ? ((regoff_t) ((ptr) - string1))		\
+   : ((regoff_t) ((ptr) - string2 + size1)))
+
+/* 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;						\
+    }
 
-/* Maximum size of failure stack.  Beyond this, overflow is an error.  */
 
-int re_max_failures = 2000;
+/* 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)
+
+/* Disabled due to a compiler bug -- see comment at case wordbound */
+#if 0
+/* 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))
+#endif
 
-static int memcmp_translate();
-/* Match the pattern described by PBUFP
-   against data which is the virtual concatenation of STRING1 and STRING2.
-   SIZE1 and SIZE2 are the sizes of the two data strings.
-   Start the match at position POS.
-   Do not consider matching past the position MSTOP.
+/* Free everything we malloc.  */
+#ifdef MATCH_MAY_ALLOCATE
+# define FREE_VAR(var) if (var) REGEX_FREE (var); var = NULL
+# define FREE_VARIABLES()						\
+  do {									\
+    REGEX_FREE_STACK (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
+# define FREE_VARIABLES() ((void)0) /* Do nothing!  But inhibit gcc warning. */
+#endif /* not MATCH_MAY_ALLOCATE */
+
+/* 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.  */
 
-   If pbufp->fastmap is nonzero, then it had better be up to date.
+#ifndef emacs   /* Emacs never uses this.  */
+/* re_match is like re_match_2 except it takes only a single string.  */
 
-   The reason that the data to match are specified as two components
-   which are to be regarded as concatenated
-   is so this function can be used directly on the contents of an Emacs buffer.
+int
+re_match (bufp, string, size, pos, regs)
+     struct re_pattern_buffer *bufp;
+     const char *string;
+     int size, pos;
+     struct re_registers *regs;
+{
+  int result = re_match_2_internal (bufp, NULL, 0, string, size,
+				    pos, regs, size);
+# ifndef REGEX_MALLOC
+#  ifdef C_ALLOCA
+  alloca (0);
+#  endif
+# endif
+  return result;
+}
+# ifdef _LIBC
+weak_alias (__re_match, re_match)
+# endif
+#endif /* not emacs */
 
-   -1 is returned if there is no match.  -2 is returned if there is
-   an error (such as match stack overflow).  Otherwise the value is the length
-   of the substring which was matched.  */
+static boolean group_match_null_string_p _RE_ARGS ((unsigned char **p,
+						    unsigned char *end,
+						register_info_type *reg_info));
+static boolean alt_match_null_string_p _RE_ARGS ((unsigned char *p,
+						  unsigned char *end,
+						register_info_type *reg_info));
+static boolean common_op_match_null_string_p _RE_ARGS ((unsigned char **p,
+							unsigned char *end,
+						register_info_type *reg_info));
+static int bcmp_translate _RE_ARGS ((const char *s1, const char *s2,
+				     int len, char *translate));
+
+/* 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 (pbufp, string1, size1, string2, size2, pos, regs, mstop)
-     struct re_pattern_buffer *pbufp;
-     unsigned char *string1, *string2;
+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;
+{
+  int result = re_match_2_internal (bufp, string1, size1, string2, size2,
+				    pos, regs, stop);
+#ifndef REGEX_MALLOC
+# ifdef C_ALLOCA
+  alloca (0);
+# endif
+#endif
+  return result;
+}
+#ifdef _LIBC
+weak_alias (__re_match_2, re_match_2)
+#endif
+
+/* This is a separate function so that we can force an alloca cleanup
+   afterwards.  */
+static int
+re_match_2_internal (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 mstop;
+     int stop;
 {
-  register unsigned char *p = (unsigned char *) pbufp->buffer;
-  register unsigned char *pend = p + pbufp->used;
-  /* End of first string */
-  unsigned char *end1;
-  /* End of second string */
-  unsigned char *end2;
-  /* Pointer just past last char to consider matching */
-  unsigned char *end_match_1, *end_match_2;
-  register unsigned char *d, *dend;
-  register int mcnt;
-  unsigned char *translate = (unsigned char *) pbufp->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 two char *'s.
-    The first one pushed is where to resume scanning the pattern;
-    the second pushed is where to resume scanning the strings.
-    If the latter is zero, the failure point is a "dummy".
-    If a failure happens and the innermost failure point is dormant,
-    it discards that failure point and tries the next one. */
-
-  unsigned char *initial_stack[2 * NFAILURES];
-  unsigned char **stackb = initial_stack;
-  unsigned char **stackp = stackb, **stacke = &stackb[2 * NFAILURES];
-
-  /* Information on the "contents" of registers.
-     These are pointers into the input strings; they record
-     just what was matched (on this attempt) by some part of the pattern.
-     The start_memory command stores the start of a register's contents
-     and the stop_memory command stores the end.
-
-     At that point, regstart[regnum] points to the first character in the register,
-     regend[regnum] points to the first character beyond the end of the register,
-     regstart_seg1[regnum] is true iff regstart[regnum] points into string1,
-     and regend_seg1[regnum] is true iff regend[regnum] points into string1.  */
-
-  unsigned char *regstart[RE_NREGS];
-  unsigned char *regend[RE_NREGS];
-  unsigned char regstart_seg1[RE_NREGS], regend_seg1[RE_NREGS];
-
-  /* Set up pointers to ends of strings.
-     Don't allow the second string to be empty unless both are empty.  */
-  if (!size2)
+  /* 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;
+
+  /* Mark the opcode just after a start_memory, so we can test for an
+     empty subpattern when we get to the stop_memory.  */
+  unsigned char *just_past_start_mem = 0;
+
+  /* We use this to map every character in the string.  */
+  RE_TRANSLATE_TYPE 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.  */
+#ifdef MATCH_MAY_ALLOCATE /* otherwise, this is global.  */
+  fail_stack_type fail_stack;
+#endif
+#ifdef DEBUG
+  static unsigned failure_id = 0;
+  unsigned nfailure_points_pushed = 0, nfailure_points_popped = 0;
+#endif
+
+#ifdef REL_ALLOC
+  /* This holds the pointer to the failure stack, when
+     it is allocated relocatably.  */
+  fail_stack_elt_t *failure_stack_ptr;
+#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.  */
+  size_t num_regs = bufp->re_nsub + 1;
+
+  /* The currently active registers.  */
+  active_reg_t lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+  active_reg_t 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.)  */
+#ifdef MATCH_MAY_ALLOCATE /* otherwise, these are global.  */
+  const char **regstart, **regend;
+#endif
+
+  /* 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.  */
+#ifdef MATCH_MAY_ALLOCATE /* otherwise, these are global.  */
+  const char **old_regstart, **old_regend;
+#endif
+
+  /* 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.  */
+#ifdef MATCH_MAY_ALLOCATE /* otherwise, this is global.  */
+  register_info_type *reg_info;
+#endif
+
+  /* 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;
+#ifdef MATCH_MAY_ALLOCATE /* otherwise, these are global.  */
+  const char **best_regstart, **best_regend;
+#endif
+
+  /* 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;
+
+  /* This helps SET_REGS_MATCHED avoid doing redundant work.  */
+  int set_regs_matched_done = 0;
+
+  /* Used when we pop values we don't care about.  */
+#ifdef MATCH_MAY_ALLOCATE /* otherwise, these are global.  */
+  const char **reg_dummy;
+  register_info_type *reg_info_dummy;
+#endif
+
+#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 ();
+
+#ifdef MATCH_MAY_ALLOCATE
+  /* 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;
+        }
+    }
+  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 /* MATCH_MAY_ALLOCATE */
+
+  /* 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; (unsigned) 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;
@@ -1111,649 +3984,1824 @@ re_match_2 (pbufp, string1, size1, string2, size2, pos, regs, mstop)
   end1 = string1 + size1;
   end2 = string2 + size2;
 
-  /* Compute where to stop matching, within the two strings */
-  if (mstop <= size1)
+  /* Compute where to stop matching, within the two strings.  */
+  if (stop <= size1)
     {
-      end_match_1 = string1 + mstop;
+      end_match_1 = string1 + stop;
       end_match_2 = string2;
     }
   else
     {
       end_match_1 = end1;
-      end_match_2 = string2 + mstop - size1;
+      end_match_2 = string2 + stop - size1;
     }
 
-  /* Initialize \) text positions to -1
-     to mark ones that no \( or \) has been seen for.  */
-
-  for (mcnt = 0; mcnt < (int) (sizeof (regend) / sizeof (*regend)); mcnt++)
-    regend[mcnt] = (unsigned char *) -1;
-
   /* `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 (pos <= size1)
-    d = string1 + pos, dend = end_match_1;
+     `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;
-
-/* Write PREFETCH; just before fetching a character with *d.  */
-#define PREFETCH \
- while (d == dend)						    \
-  { if (dend == end_match_2) goto fail;  /* end of string2 => failure */   \
-    d = string2;  /* end of string1 => advance to string2. */       \
-    dend = end_match_2; }
+    {
+      d = string2 + pos - size1;
+      dend = end_match_2;
+    }
 
-  /* This loop loops over pattern commands.
-     It exits by returning from the function if match is complete,
-     or it drops through if match fails at this starting point in the input data. */
+  DEBUG_PRINT1 ("The compiled pattern is:\n");
+  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");
 
-  while (1)
+  /* 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 (;;)
     {
+#ifdef _LIBC
+      DEBUG_PRINT2 ("\n%p: ", p);
+#else
+      DEBUG_PRINT2 ("\n0x%x: ", p);
+#endif
+
       if (p == pend)
-	/* End of pattern means we have succeeded! */
-	{
-	  /* If caller wants register contents data back, convert it to indices */
-	  if (regs)
+	{ /* 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)
 	    {
- 	      regs->start[0] = pos;
- 	      if (dend == end_match_1)
- 		regs->end[0] = d - string1;
- 	      else
- 		regs->end[0] = d - string2 + size1;
- 	      for (mcnt = 1; mcnt < RE_NREGS; mcnt++)
-		{
-		  if (regend[mcnt] == (unsigned char *) -1)
+	      /* 1 if this match ends in the same string (string1 or string2)
+		 as the best previous match.  */
+	      boolean same_str_p = (FIRST_STRING_P (match_end)
+				    == MATCHING_IN_FIRST_STRING);
+	      /* 1 if this match is the best seen so far.  */
+	      boolean best_match_p;
+
+	      /* AIX compiler got confused when this was combined
+		 with the previous declaration.  */
+	      if (same_str_p)
+		best_match_p = d > match_end;
+	      else
+		best_match_p = !MATCHING_IN_FIRST_STRING;
+
+              DEBUG_PRINT1 ("backtracking.\n");
+
+              if (!FAIL_STACK_EMPTY ())
+                { /* More failure points to try.  */
+
+                  /* If exceeds best match so far, save it.  */
+                  if (!best_regs_set || best_match_p)
+                    {
+                      best_regs_set = true;
+                      match_end = d;
+
+                      DEBUG_PRINT1 ("\nSAVING match as best so far.\n");
+
+                      for (mcnt = 1; (unsigned) mcnt < num_regs; mcnt++)
+                        {
+                          best_regstart[mcnt] = regstart[mcnt];
+                          best_regend[mcnt] = regend[mcnt];
+                        }
+                    }
+                  goto fail;
+                }
+
+              /* If no failure points, don't restore garbage.  And if
+                 last match is real best match, don't restore second
+                 best one. */
+              else if (best_regs_set && !best_match_p)
+                {
+  	        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; (unsigned) mcnt < num_regs; mcnt++)
 		    {
-		      regs->start[mcnt] = -1;
-		      regs->end[mcnt] = -1;
-		      continue;
+		      regstart[mcnt] = best_regstart[mcnt];
+		      regend[mcnt] = best_regend[mcnt];
 		    }
- 		  if (regstart_seg1[mcnt])
-		    regs->start[mcnt] = regstart[mcnt] - string1;
-		  else
-		    regs->start[mcnt] = regstart[mcnt] - string2 + size1;
- 		  if (regend_seg1[mcnt])
-		    regs->end[mcnt] = regend[mcnt] - string1;
-		  else
-		    regs->end[mcnt] = regend[mcnt] - string2 + size1;
+                }
+            } /* d != end_match_2 */
+
+	succeed_label:
+          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)
+		    {
+		      FREE_VARIABLES ();
+		      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)
+			{
+			  FREE_VARIABLES ();
+			  return -2;
+			}
+                    }
+                }
+              else
+		{
+		  /* These braces fend off a "empty body in an else-statement"
+		     warning under GCC when assert expands to nothing.  */
+		  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
+				  ? ((regoff_t) (d - string1))
+			          : ((regoff_t) (d - string2 + size1)));
+                }
+
+              /* Go through the first `min (num_regs, regs->num_regs)'
+                 registers, since that is all we initialized.  */
+	      for (mcnt = 1; (unsigned) 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]
+			= (regoff_t) POINTER_TO_OFFSET (regstart[mcnt]);
+                      regs->end[mcnt]
+			= (regoff_t) 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; (unsigned) mcnt < regs->num_regs; mcnt++)
+                regs->start[mcnt] = regs->end[mcnt] = -1;
+	    } /* regs && !bufp->no_sub */
+
+          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);
+
+          FREE_VARIABLES ();
+          return mcnt;
+        }
+
+      /* Otherwise match next pattern command.  */
+      switch (SWITCH_ENUM_CAST ((re_opcode_t) *p++))
+	{
+        /* 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;
+
+	case succeed:
+          DEBUG_PRINT1 ("EXECUTING succeed.\n");
+	  goto succeed_label;
+
+        /* 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 ((unsigned char) translate[(unsigned char) *d++]
+		      != (unsigned char) *p++)
+                    goto fail;
 		}
+	      while (--mcnt);
 	    }
- 	  if (dend == end_match_1)
-	    return (d - string1 - pos);
 	  else
-	    return d - string2 + size1 - pos;
-	}
+	    {
+	      do
+		{
+		  PREFETCH ();
+		  if (*d++ != (char) *p++) goto fail;
+		}
+	      while (--mcnt);
+	    }
+	  SET_REGS_MATCHED ();
+          break;
 
-      /* Otherwise match next pattern command */
-#ifdef SWITCH_ENUM_BUG
-      switch ((int) ((enum regexpcode) *p++))
-#else
-      switch ((enum regexpcode) *p++)
-#endif
-	{
 
-	/* \( is represented by a start_memory, \) by a stop_memory.
-	    Both of those commands contain a "register number" argument.
-	    The text matched within the \( and \) is recorded under that number.
-	    Then, \<digit> turns into a `duplicate' command which
-	    is followed by the numeric value of <digit> as the register number. */
+        /* Match any character except possibly a newline or a null.  */
+	case anychar:
+          DEBUG_PRINT1 ("EXECUTING anychar.\n");
 
-	case start_memory:
-	  regstart[*p] = d;
- 	  regstart_seg1[*p++] = (dend == end_match_1);
+          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;
+
+	  /* Clear this whenever we change the register activity status.  */
+	  set_regs_matched_done = 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;
+	  just_past_start_mem = p;
+
+          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:
-	  regend[*p] = d;
- 	  regend_seg1[*p++] = (dend == end_match_1);
-	  break;
+	  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;
+
+	  /* Clear this whenever we change the register activity status.  */
+	  set_regs_matched_done = 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])
+               || just_past_start_mem == p - 1)
+	      && (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].
 
-	case duplicate:
+                     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 < (unsigned) *p + (unsigned) *(p + 1);
+			   r++)
+                        {
+                          regstart[r] = old_regstart[r];
+
+                          /* xx why this test?  */
+                          if (old_regend[r] >= 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:
 	  {
-	    int regno = *p++;   /* Get which register to match against */
-	    register unsigned char *d2, *dend2;
+	    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.  */
 
-	    d2 = regstart[regno];
- 	    dend2 = ((regstart_seg1[regno] == regend_seg1[regno])
+            dend2 = ((FIRST_STRING_P (regstart[regno])
+		      == FIRST_STRING_P (regend[regno]))
 		     ? regend[regno] : end_match_1);
-	    while (1)
+	    for (;;)
 	      {
-		/* Advance to next segment in register contents, if necessary */
+		/* If necessary, advance to next segment in register
+                   contents.  */
 		while (d2 == dend2)
 		  {
 		    if (dend2 == end_match_2) break;
 		    if (dend2 == regend[regno]) break;
-		    d2 = string2, dend2 = regend[regno];  /* end of string1 => advance to string2. */
+
+                    /* End of string1 => advance to string2. */
+                    d2 = string2;
+                    dend2 = regend[regno];
 		  }
 		/* At end of register contents => success */
 		if (d2 == dend2) break;
 
-		/* Advance to next segment in data being matched, if necessary */
-		PREFETCH;
+		/* If necessary, advance to next segment in data.  */
+		PREFETCH ();
 
-		/* mcnt gets # consecutive chars to compare */
+		/* How many characters left in this segment to match.  */
 		mcnt = dend - d;
-		if (mcnt > dend2 - d2)
+
+		/* 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 skip them. */
-		if (translate ? memcmp_translate (d, d2, mcnt, translate) : memcmp (d, d2, mcnt))
+
+		/* Compare that many; failure if mismatch, else move
+                   past them.  */
+		if (translate
+                    ? bcmp_translate (d, d2, mcnt, translate)
+                    : memcmp (d, d2, mcnt))
 		  goto fail;
 		d += mcnt, d2 += mcnt;
+
+		/* Do this because we've match some characters.  */
+		SET_REGS_MATCHED ();
 	      }
 	  }
 	  break;
 
-	case anychar:
-	  /* fetch a data character */
-	  PREFETCH;
-	  /* Match anything but a newline.  */
-	  if ((translate ? translate[*d++] : *d++) == '\n')
-	    goto fail;
-	  break;
-
-	case charset:
-	case charset_not:
-	  {
-	    /* Nonzero for charset_not */
-	    int not = 0;
-	    register int c;
-	    if (*(p - 1) == (unsigned char) charset_not)
-	      not = 1;
-
-	    /* fetch a data character */
-	    PREFETCH;
-
-	    if (translate)
-	      c = translate [*d];
-	    else
-	      c = *d;
-
-	    if (c < *p * BYTEWIDTH
-		&& p[1 + c / BYTEWIDTH] & (1 << (c % BYTEWIDTH)))
-	      not = !not;
 
-	    p += 1 + *p;
+        /* 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 (!not) goto fail;
-	    d++;
-	    break;
-	  }
+          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;
 
-	case begline:
-	  if (d == string1 || d[-1] == '\n')
-	    break;
-	  goto fail;
 
+        /* endline is the dual of begline.  */
 	case endline:
-	  if (d == end2
-	      || (d == end1 ? (size2 == 0 || *string2 == '\n') : *d == '\n'))
+          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;
+          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);
+#ifdef _LIBC
+          DEBUG_PRINT3 (" %d (to %p):\n", mcnt, p + mcnt);
+#else
+          DEBUG_PRINT3 (" %d (to 0x%x):\n", mcnt, p + mcnt);
+#endif
+
+          PUSH_FAILURE_POINT (p + mcnt, NULL, -2);
+          break;
 
-	/* "or" constructs ("|") are handled by starting each alternative
-	    with an on_failure_jump that points to the start of the next alternative.
-	    Each alternative except the last ends with a jump to the joining point.
-	    (Actually, each jump except for the last one really jumps
-	     to the following jump, because tensioning the jumps is a hassle.) */
 
-	/* The start of a stupid repeat has an on_failure_jump that points
-	   past the end of the repeat text.
-	   This makes a failure point so that, on failure to match a repetition,
-	   matching restarts past as many repetitions have been found
-	   with no way to fail and look for another one.  */
+	/* Uses of on_failure_jump:
 
-	/* A smart repeat is similar but loops back to the on_failure_jump
-	   so that each repetition makes another failure point. */
+           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:
-	  if (stackp == stacke)
-	    {
-	      unsigned char **stackx;
-	      if (stacke - stackb > re_max_failures * 2)
-		return -2;
-	      stackx = (unsigned char **) alloca (2 * (stacke - stackb)
-					 * sizeof (char *));
-	      memcpy (stackx, stackb, (stacke - stackb) * sizeof (char *));
-	      stackp = stackx + (stackp - stackb);
-	      stacke = stackx + 2 * (stacke - stackb);
-	      stackb = stackx;
-	    }
-	  mcnt = *p++ & 0377;
-	  mcnt += SIGN_EXTEND_CHAR (*(char *)p) << 8;
-	  p++;
-	  *stackp++ = mcnt + p;
-	  *stackp++ = d;
-	  break;
+        on_failure:
+          DEBUG_PRINT1 ("EXECUTING on_failure_jump");
 
-	/* The end of a smart repeat has an maybe_finalize_jump back.
-	   Change it either to a finalize_jump or an ordinary jump. */
+          EXTRACT_NUMBER_AND_INCR (mcnt, p);
+#ifdef _LIBC
+          DEBUG_PRINT3 (" %d (to %p)", mcnt, p + mcnt);
+#else
+          DEBUG_PRINT3 (" %d (to 0x%x)", mcnt, p + mcnt);
+#endif
 
-	case maybe_finalize_jump:
-	  mcnt = *p++ & 0377;
-	  mcnt += SIGN_EXTEND_CHAR (*(char *)p) << 8;
-	  p++;
-	  {
+          /* 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 \(zz\(a*\)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 what follows with the begining of the repeat.
-	       If we can establish that there is nothing that they would
-	       both match, we can change to finalize_jump */
-	    while (p2 != pend
-		   && (*p2 == (unsigned char) stop_memory
-		       || *p2 == (unsigned char) start_memory))
-	      p2++;
-	    if (p2 == pend)
-	      p[-3] = (unsigned char) finalize_jump;
-	    else if (*p2 == (unsigned char) exactn
-		     || *p2 == (unsigned char) endline)
+
+            /* 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.
+	       If what follows this loop is a ...+ construct,
+	       look at what begins its body, since we will have to
+	       match at least one of that.  */
+	    while (1)
+	      {
+		if (p2 + 2 < pend
+		    && ((re_opcode_t) *p2 == stop_memory
+			|| (re_opcode_t) *p2 == start_memory))
+		  p2 += 3;
+		else if (p2 + 6 < pend
+			 && (re_opcode_t) *p2 == dummy_failure_jump)
+		  p2 += 6;
+		else
+		  break;
+	      }
+
+	    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 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 int c = *p2 == (unsigned char) endline ? '\n' : p2[2];
-		register unsigned char *p1 = p + mcnt;
-		/* p1[0] ... p1[2] are an on_failure_jump.
-		   Examine what follows that */
-		if (p1[3] == (unsigned char) exactn && p1[5] != c)
-		  p[-3] = (unsigned char) finalize_jump;
-		else if (p1[3] == (unsigned char) charset
-			 || p1[3] == (unsigned char) charset_not)
+		register unsigned char c
+                  = *p2 == (unsigned char) endline ? '\n' : p2[2];
+
+                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 = p1[3] == (unsigned char) charset_not;
-		    if (c < p1[4] * BYTEWIDTH
+		    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 1 if c would match */
-		    /* That means it is not safe to finalize */
+
+                    /* `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) finalize_jump;
+                      {
+  		        p[-3] = (unsigned char) pop_failure_jump;
+                        DEBUG_PRINT1 ("  No match => pop_failure_jump.\n");
+                      }
+		  }
+	      }
+            else if ((re_opcode_t) *p2 == charset)
+	      {
+#ifdef DEBUG
+		register unsigned char c
+                  = *p2 == (unsigned char) endline ? '\n' : p2[2];
+#endif
+
+#if 0
+                if ((re_opcode_t) p1[3] == exactn
+		    && ! ((int) p2[1] * BYTEWIDTH > (int) p1[5]
+			  && (p2[2 + p1[5] / BYTEWIDTH]
+			      & (1 << (p1[5] % BYTEWIDTH)))))
+#else
+                if ((re_opcode_t) p1[3] == exactn
+		    && ! ((int) p2[1] * BYTEWIDTH > (int) p1[4]
+			  && (p2[2 + p1[4] / BYTEWIDTH]
+			      & (1 << (p1[4] % BYTEWIDTH)))))
+#endif
+                  {
+  		    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_not)
+		  {
+		    int idx;
+		    /* We win if the charset_not inside the loop
+		       lists every character listed in the charset after.  */
+		    for (idx = 0; idx < (int) p2[1]; idx++)
+		      if (! (p2[2 + idx] == 0
+			     || (idx < (int) p1[4]
+				 && ((p2[2 + idx] & ~ p1[5 + idx]) == 0))))
+			break;
+
+		    if (idx == p2[1])
+                      {
+  		        p[-3] = (unsigned char) pop_failure_jump;
+                        DEBUG_PRINT1 ("  No match => pop_failure_jump.\n");
+                      }
+		  }
+		else if ((re_opcode_t) p1[3] == charset)
+		  {
+		    int idx;
+		    /* We win if the charset inside the loop
+		       has no overlap with the one after the loop.  */
+		    for (idx = 0;
+			 idx < (int) p2[1] && idx < (int) p1[4];
+			 idx++)
+		      if ((p2[2 + idx] & p1[5 + idx]) != 0)
+			break;
+
+		    if (idx == p2[1] || idx == p1[4])
+                      {
+  		        p[-3] = (unsigned char) pop_failure_jump;
+                        DEBUG_PRINT1 ("  No match => pop_failure_jump.\n");
+                      }
 		  }
 	      }
 	  }
-	  p -= 2;
-	  if (p[-1] != (unsigned char) finalize_jump)
+	  p -= 2;		/* Point at relative address again.  */
+	  if ((re_opcode_t) p[-1] != pop_failure_jump)
 	    {
 	      p[-1] = (unsigned char) jump;
-	      goto nofinalize;
+              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'.  */
+            active_reg_t 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.  */
+
+	unconditional_jump:
+#ifdef _LIBC
+	  DEBUG_PRINT2 ("\n%p: ", p);
+#else
+	  DEBUG_PRINT2 ("\n0x%x: ", p);
+#endif
+          /* Note fall through.  */
+
+        /* Unconditionally jump (without popping any failure points).  */
+        case jump:
+	  EXTRACT_NUMBER_AND_INCR (mcnt, p);	/* Get the amount to jump.  */
+          DEBUG_PRINT2 ("EXECUTING jump %d ", mcnt);
+	  p += mcnt;				/* Do the jump.  */
+#ifdef _LIBC
+          DEBUG_PRINT2 ("(to %p).\n", p);
+#else
+          DEBUG_PRINT2 ("(to 0x%x).\n", p);
+#endif
+	  break;
 
-	/* The end of a stupid repeat has a finalize-jump
-	   back to the start, where another failure point will be made
-	   which will point after all the repetitions found so far. */
 
-	case finalize_jump:
-	  stackp -= 2;
+        /* 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 (NULL, NULL, -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 (NULL, NULL, -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);
+#ifdef _LIBC
+               DEBUG_PRINT3 ("  Setting %p to %d.\n", p - 2, mcnt);
+#else
+               DEBUG_PRINT3 ("  Setting 0x%x to %d.\n", p - 2, mcnt);
+#endif
+            }
+	  else if (mcnt == 0)
+            {
+#ifdef _LIBC
+              DEBUG_PRINT2 ("  Setting two bytes from %p to no_op.\n", p+2);
+#else
+              DEBUG_PRINT2 ("  Setting two bytes from 0x%x to no_op.\n", p+2);
+#endif
+	      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);
+#ifdef _LIBC
+               DEBUG_PRINT3 ("  Setting %p to %d.\n", p + 2, mcnt);
+#else
+               DEBUG_PRINT3 ("  Setting 0x%x to %d.\n", p + 2, mcnt);
+#endif
+	       goto unconditional_jump;
+            }
+          /* If don't have to jump any more, skip over the rest of command.  */
+	  else
+	    p += 4;
+          break;
 
-	case jump:
-	nofinalize:
-	  mcnt = *p++ & 0377;
-	  mcnt += SIGN_EXTEND_CHAR (*(char *)p) << 8;
-	  p += mcnt + 1;	/* The 1 compensates for missing ++ above */
-	  break;
+	case set_number_at:
+	  {
+            DEBUG_PRINT1 ("EXECUTING set_number_at.\n");
 
-	case dummy_failure_jump:
-	  if (stackp == stacke)
-	    {
-	      unsigned char **stackx
-		= (unsigned char **) alloca (2 * (stacke - stackb)
-					     * sizeof (char *));
-	      memcpy (stackx, stackb, (stacke - stackb) * sizeof (char *));
-	      stackp = stackx + (stackp - stackb);
-	      stacke = stackx + 2 * (stacke - stackb);
-	      stackb = stackx;
-	    }
-	  *stackp++ = 0;
-	  *stackp++ = 0;
-	  goto nofinalize;
+            EXTRACT_NUMBER_AND_INCR (mcnt, p);
+            p1 = p + mcnt;
+            EXTRACT_NUMBER_AND_INCR (mcnt, p);
+#ifdef _LIBC
+            DEBUG_PRINT3 ("  Setting %p to %d.\n", p1, mcnt);
+#else
+            DEBUG_PRINT3 ("  Setting 0x%x to %d.\n", p1, mcnt);
+#endif
+	    STORE_NUMBER (p1, mcnt);
+            break;
+          }
+
+#if 0
+	/* The DEC Alpha C compiler 3.x generates incorrect code for the
+	   test  WORDCHAR_P (d - 1) != WORDCHAR_P (d)  in the expansion of
+	   AT_WORD_BOUNDARY, so this code is disabled.  Expanding the
+	   macro and introducing temporary variables works around the bug.  */
 
 	case wordbound:
-	  if (d == string1  /* Points to first char */
-	      || d == end2  /* Points to end */
-	      || (d == end1 && size2 == 0)) /* Points to end */
-	    break;
-	  if ((SYNTAX (d[-1]) == Sword)
-	      != (SYNTAX (d == end1 ? *string2 : *d) == Sword))
+	  DEBUG_PRINT1 ("EXECUTING wordbound.\n");
+	  if (AT_WORD_BOUNDARY (d))
 	    break;
 	  goto fail;
 
 	case notwordbound:
-	  if (d == string1  /* Points to first char */
-	      || d == end2  /* Points to end */
-	      || (d == end1 && size2 == 0)) /* Points to end */
-	    goto fail;
-	  if ((SYNTAX (d[-1]) == Sword)
-	      != (SYNTAX (d == end1 ? *string2 : *d) == Sword))
+	  DEBUG_PRINT1 ("EXECUTING notwordbound.\n");
+	  if (AT_WORD_BOUNDARY (d))
 	    goto fail;
 	  break;
+#else
+	case wordbound:
+	{
+	  boolean prevchar, thischar;
 
-	case wordbeg:
-	  if (d == end2  /* Points to end */
-	      || (d == end1 && size2 == 0) /* Points to end */
-	      || SYNTAX (* (d == end1 ? string2 : d)) != Sword) /* Next char not a letter */
-	    goto fail;
-	  if (d == string1  /* Points to first char */
-	      || SYNTAX (d[-1]) != Sword)  /* prev char not letter */
+	  DEBUG_PRINT1 ("EXECUTING wordbound.\n");
+	  if (AT_STRINGS_BEG (d) || AT_STRINGS_END (d))
 	    break;
-	  goto fail;
 
-	case wordend:
-	  if (d == string1  /* Points to first char */
-	      || SYNTAX (d[-1]) != Sword)  /* prev char not letter */
-	    goto fail;
-	  if (d == end2  /* Points to end */
-	      || (d == end1 && size2 == 0) /* Points to end */
-	      || SYNTAX (d == end1 ? *string2 : *d) != Sword) /* Next char not a letter */
+	  prevchar = WORDCHAR_P (d - 1);
+	  thischar = WORDCHAR_P (d);
+	  if (prevchar != thischar)
 	    break;
 	  goto fail;
+	}
 
-#ifdef emacs
-	case before_dot:
-	  if (((d - string2 <= (unsigned) size2)
-	       ? d - bf_p2 : d - bf_p1)
-	      <= point)
-	    goto fail;
-	  break;
+      case notwordbound:
+	{
+	  boolean prevchar, thischar;
 
-	case at_dot:
-	  if (((d - string2 <= (unsigned) size2)
-	       ? d - bf_p2 : d - bf_p1)
-	      == point)
+	  DEBUG_PRINT1 ("EXECUTING notwordbound.\n");
+	  if (AT_STRINGS_BEG (d) || AT_STRINGS_END (d))
 	    goto fail;
-	  break;
 
-	case after_dot:
-	  if (((d - string2 <= (unsigned) size2)
-	       ? d - bf_p2 : d - bf_p1)
-	      >= point)
+	  prevchar = WORDCHAR_P (d - 1);
+	  thischar = WORDCHAR_P (d);
+	  if (prevchar != thischar)
 	    goto fail;
 	  break;
+	}
+#endif
 
-	case wordchar:
-	  mcnt = (int) Sword;
-	  goto matchsyntax;
+	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
+  	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;
 
 	case syntaxspec:
+          DEBUG_PRINT2 ("EXECUTING syntaxspec %d.\n", mcnt);
 	  mcnt = *p++;
-	matchsyntax:
-	  PREFETCH;
-	  if (SYNTAX (*d++) != (enum syntaxcode) mcnt) goto fail;
-	  break;
-	  
-	case notwordchar:
+	  goto matchsyntax;
+
+        case wordchar:
+          DEBUG_PRINT1 ("EXECUTING Emacs wordchar.\n");
 	  mcnt = (int) Sword;
-	  goto matchnotsyntax;
+        matchsyntax:
+	  PREFETCH ();
+	  /* Can't use *d++ here; SYNTAX may be an unsafe macro.  */
+	  d++;
+	  if (SYNTAX (d[-1]) != (enum syntaxcode) mcnt)
+	    goto fail;
+          SET_REGS_MATCHED ();
+	  break;
 
 	case notsyntaxspec:
+          DEBUG_PRINT2 ("EXECUTING notsyntaxspec %d.\n", mcnt);
 	  mcnt = *p++;
-	matchnotsyntax:
-	  PREFETCH;
-	  if (SYNTAX (*d++) == (enum syntaxcode) mcnt) goto fail;
-	  break;
-#else
+	  goto matchnotsyntax;
+
+        case notwordchar:
+          DEBUG_PRINT1 ("EXECUTING Emacs notwordchar.\n");
+	  mcnt = (int) Sword;
+        matchnotsyntax:
+	  PREFETCH ();
+	  /* Can't use *d++ here; SYNTAX may be an unsafe macro.  */
+	  d++;
+	  if (SYNTAX (d[-1]) == (enum syntaxcode) mcnt)
+	    goto fail;
+	  SET_REGS_MATCHED ();
+          break;
+
+#else /* not emacs */
 	case wordchar:
-	  PREFETCH;
-	  if (SYNTAX (*d++) == 0) goto fail;
+          DEBUG_PRINT1 ("EXECUTING non-Emacs wordchar.\n");
+	  PREFETCH ();
+          if (!WORDCHAR_P (d))
+            goto fail;
+	  SET_REGS_MATCHED ();
+          d++;
 	  break;
-	  
+
 	case notwordchar:
-	  PREFETCH;
-	  if (SYNTAX (*d++) != 0) goto fail;
+          DEBUG_PRINT1 ("EXECUTING non-Emacs notwordchar.\n");
+	  PREFETCH ();
+	  if (WORDCHAR_P (d))
+            goto fail;
+          SET_REGS_MATCHED ();
+          d++;
 	  break;
 #endif /* not emacs */
 
-	case begbuf:
-	  if (d == string1)	/* Note, d cannot equal string2 */
-	    break;		/* unless string1 == string2.  */
-	  goto fail;
+        default:
+          abort ();
+	}
+      continue;  /* Successfully executed one pattern command; keep going.  */
 
-	case endbuf:
-	  if (d == end2 || (d == end1 && size2 == 0))
-	    break;
-	  goto fail;
 
-	case exactn:
-	  /* Match the next few pattern characters exactly.
-	     mcnt is how many characters to match. */
-	  mcnt = *p++;
-	  if (translate)
-	    {
-	      do
-		{
-		  PREFETCH;
-		  if (translate[*d++] != *p++) goto fail;
-		}
-	      while (--mcnt);
-	    }
-	  else
+    /* 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)
 	    {
-	      do
-		{
-		  PREFETCH;
-		  if (*d++ != *p++) goto fail;
-		}
-	      while (--mcnt);
-	    }
-	  break;
-	case unused:
-	case before_dot:
-	case at_dot:
-	case after_dot:
-	case syntaxspec:
-	case notsyntaxspec:
+              /* 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:
-	  break;
-	}
-      continue;    /* Successfully matched one pattern command; keep matching */
+          if (!common_op_match_null_string_p (&p1, end, reg_info))
+            return false;
+        }
+    }  /* while p1 < end */
 
-      /* Jump here if any matching operation fails. */
-    fail:
-      if (stackp != stackb)
-	/* A restart point is known.  Restart there and pop it. */
-	{
-	  if (!stackp[-2])
-	    {   /* If innermost failure point is dormant, flush it and keep looking */
-	      stackp -= 2;
-	      goto fail;
-	    }
-	  d = *--stackp;
-	  p = *--stackp;
-	  if (d >= string1 && d <= end1)
-	    dend = end_match_1;
-	}
-      else break;   /* Matching at this starting point really fails! */
-    }
-  return -1;         /* Failure to match */
-}
+  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
-memcmp_translate (s1, s2, len, translate)
-     unsigned char *s1, *s2;
+bcmp_translate (s1, s2, len, translate)
+     const char *s1, *s2;
      register int len;
-     unsigned char *translate;
+     RE_TRANSLATE_TYPE translate;
 {
-  register unsigned char *p1 = s1, *p2 = s2;
+  register const unsigned char *p1 = (const unsigned char *) s1;
+  register const unsigned char *p2 = (const unsigned char *) s2;
   while (len)
     {
-      if (translate [*p1++] != translate [*p2++]) return 1;
+      if (translate[*p1++] != translate[*p2++]) return 1;
       len--;
     }
   return 0;
 }
 
-/* Entry points compatible with bsd4.2 regex library */
+/* Entry points for GNU code.  */
 
-#ifndef emacs
+/* 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;
+     size_t 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);
+
+  if (!ret)
+    return NULL;
+  return gettext (re_error_msgid[(int) ret]);
+}
+#ifdef _LIBC
+weak_alias (__re_compile_pattern, re_compile_pattern)
+#endif
+
+/* Entry points compatible with 4.2 BSD regex library.  We don't define
+   them unless specifically requested.  */
+
+#if defined _REGEX_RE_COMP || defined _LIBC
 
+/* BSD has one and only one pattern buffer.  */
 static struct re_pattern_buffer re_comp_buf;
 
 char *
+#ifdef _LIBC
+/* Make these definitions weak in libc, so POSIX programs can redefine
+   these names if they don't use our functions, and still use
+   regcomp/regexec below without link errors.  */
+weak_function
+#endif
 re_comp (s)
-     const char *s;
+    const char *s;
 {
+  reg_errcode_t ret;
+
   if (!s)
     {
       if (!re_comp_buf.buffer)
-	return "No previous regular expression";
+	return gettext ("No previous regular expression");
       return 0;
     }
 
   if (!re_comp_buf.buffer)
     {
-      if (!(re_comp_buf.buffer = (char *) malloc (200)))
-	return "Memory exhausted";
+      re_comp_buf.buffer = (unsigned char *) malloc (200);
+      if (re_comp_buf.buffer == NULL)
+        return gettext (re_error_msgid[(int) REG_ESPACE]);
       re_comp_buf.allocated = 200;
-      if (!(re_comp_buf.fastmap = (char *) malloc (1 << BYTEWIDTH)))
-	return "Memory exhausted";
+
+      re_comp_buf.fastmap = (char *) malloc (1 << BYTEWIDTH);
+      if (re_comp_buf.fastmap == NULL)
+	return gettext (re_error_msgid[(int) REG_ESPACE]);
     }
-  return re_compile_pattern (s, strlen (s), &re_comp_buf);
+
+  /* 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);
+
+  if (!ret)
+    return NULL;
+
+  /* Yes, we're discarding `const' here if !HAVE_LIBINTL.  */
+  return (char *) gettext (re_error_msgid[(int) ret]);
 }
 
+
 int
+#ifdef _LIBC
+weak_function
+#endif
 re_exec (s)
-     char *s;
+    const char *s;
 {
-  int len = strlen (s);
-  return 0 <= re_search (&re_comp_buf, s, len, 0, len, 0);
+  const int len = strlen (s);
+  return
+    0 <= re_search (&re_comp_buf, s, len, 0, len, (struct re_registers *) 0);
 }
 
-#endif /* emacs */
+#endif /* _REGEX_RE_COMP */
 
-#ifdef test
-
-#include <stdio.h>
-
-/* Indexed by a character, gives the upper case equivalent of the character */
-
-static char upcase[0400] = 
-  { 000, 001, 002, 003, 004, 005, 006, 007,
-    010, 011, 012, 013, 014, 015, 016, 017,
-    020, 021, 022, 023, 024, 025, 026, 027,
-    030, 031, 032, 033, 034, 035, 036, 037,
-    040, 041, 042, 043, 044, 045, 046, 047,
-    050, 051, 052, 053, 054, 055, 056, 057,
-    060, 061, 062, 063, 064, 065, 066, 067,
-    070, 071, 072, 073, 074, 075, 076, 077,
-    0100, 0101, 0102, 0103, 0104, 0105, 0106, 0107,
-    0110, 0111, 0112, 0113, 0114, 0115, 0116, 0117,
-    0120, 0121, 0122, 0123, 0124, 0125, 0126, 0127,
-    0130, 0131, 0132, 0133, 0134, 0135, 0136, 0137,
-    0140, 0101, 0102, 0103, 0104, 0105, 0106, 0107,
-    0110, 0111, 0112, 0113, 0114, 0115, 0116, 0117,
-    0120, 0121, 0122, 0123, 0124, 0125, 0126, 0127,
-    0130, 0131, 0132, 0173, 0174, 0175, 0176, 0177,
-    0200, 0201, 0202, 0203, 0204, 0205, 0206, 0207,
-    0210, 0211, 0212, 0213, 0214, 0215, 0216, 0217,
-    0220, 0221, 0222, 0223, 0224, 0225, 0226, 0227,
-    0230, 0231, 0232, 0233, 0234, 0235, 0236, 0237,
-    0240, 0241, 0242, 0243, 0244, 0245, 0246, 0247,
-    0250, 0251, 0252, 0253, 0254, 0255, 0256, 0257,
-    0260, 0261, 0262, 0263, 0264, 0265, 0266, 0267,
-    0270, 0271, 0272, 0273, 0274, 0275, 0276, 0277,
-    0300, 0301, 0302, 0303, 0304, 0305, 0306, 0307,
-    0310, 0311, 0312, 0313, 0314, 0315, 0316, 0317,
-    0320, 0321, 0322, 0323, 0324, 0325, 0326, 0327,
-    0330, 0331, 0332, 0333, 0334, 0335, 0336, 0337,
-    0340, 0341, 0342, 0343, 0344, 0345, 0346, 0347,
-    0350, 0351, 0352, 0353, 0354, 0355, 0356, 0357,
-    0360, 0361, 0362, 0363, 0364, 0365, 0366, 0367,
-    0370, 0371, 0372, 0373, 0374, 0375, 0376, 0377
-  };
+/* POSIX.2 functions.  Don't define these for Emacs.  */
 
-main (argc, argv)
-     int argc;
-     char **argv;
-{
-  char pat[80];
-  struct re_pattern_buffer buf;
-  int i;
-  char c;
-  char fastmap[(1 << BYTEWIDTH)];
+#ifndef emacs
 
-  /* Allow a command argument to specify the style of syntax.  */
-  if (argc > 1)
-    obscure_syntax = atoi (argv[1]);
+/* regcomp takes a regular expression as a string and compiles it.
 
-  buf.allocated = 40;
-  buf.buffer = (char *) malloc (buf.allocated);
-  buf.fastmap = fastmap;
-  buf.translate = upcase;
+   PREG is a regex_t *.  We do not expect any fields to be initialized,
+   since POSIX says we shouldn't.  Thus, we set
 
-  while (1)
-    {
-      gets (pat);
+     `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.
 
-      if (*pat)
-	{
-          re_compile_pattern (pat, strlen(pat), &buf);
+   PATTERN is the address of the pattern string.
 
-	  for (i = 0; i < buf.used; i++)
-	    printchar (buf.buffer[i]);
+   CFLAGS is a series of bits which affect compilation.
 
-	  putchar_unfiltered ('\n');
+     If REG_EXTENDED is set, we use POSIX extended syntax; otherwise, we
+     use POSIX basic syntax.
 
-	  printf_unfiltered ("%d allocated, %d used.\n", buf.allocated, buf.used);
+     If REG_NEWLINE is set, then . and [^...] don't match newline.
+     Also, regexec will try a match beginning after every newline.
 
-	  re_compile_fastmap (&buf);
-	  printf_unfiltered ("Allowed by fastmap: ");
-	  for (i = 0; i < (1 << BYTEWIDTH); i++)
-	    if (fastmap[i]) printchar (i);
-	  putchar_unfiltered ('\n');
-	}
+     If REG_ICASE is set, then we considers upper- and lowercase
+     versions of letters to be equivalent when matching.
 
-      gets (pat);	/* Now read the string to match against */
+     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.
 
-      i = re_match (&buf, pat, strlen (pat), 0, 0);
-      printf_unfiltered ("Match value %d.\n", i);
+   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;
+  reg_syntax_t syntax
+    = (cflags & REG_EXTENDED) ?
+      RE_SYNTAX_POSIX_EXTENDED : RE_SYNTAX_POSIX_BASIC;
+
+  /* regex_compile will allocate the space for the compiled pattern.  */
+  preg->buffer = 0;
+  preg->allocated = 0;
+  preg->used = 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
+	= (RE_TRANSLATE_TYPE) malloc (CHAR_SET_SIZE
+				      * sizeof (*(RE_TRANSLATE_TYPE)0));
+      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;
 }
+#ifdef _LIBC
+weak_alias (__regcomp, regcomp)
+#endif
 
-#ifdef NOTDEF
-print_buf (bufp)
-     struct re_pattern_buffer *bufp;
+
+/* 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 i;
-
-  printf_unfiltered ("buf is :\n----------------\n");
-  for (i = 0; i < bufp->used; i++)
-    printchar (bufp->buffer[i]);
-  
-  printf_unfiltered ("\n%d allocated, %d used.\n", bufp->allocated, bufp->used);
-  
-  printf_unfiltered ("Allowed by fastmap: ");
-  for (i = 0; i < (1 << BYTEWIDTH); i++)
-    if (bufp->fastmap[i])
-      printchar (i);
-  printf_unfiltered ("\nAllowed by translate: ");
-  if (bufp->translate)
-    for (i = 0; i < (1 << BYTEWIDTH); i++)
-      if (bufp->translate[i])
-	printchar (i);
-  printf_unfiltered ("\nfastmap is%s accurate\n", bufp->fastmap_accurate ? "" : "n't");
-  printf_unfiltered ("can %s be null\n----------", bufp->can_be_null ? "" : "not");
+  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;
 }
+#ifdef _LIBC
+weak_alias (__regexec, regexec)
 #endif
 
-printchar (c)
-     char c;
+
+/* 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;
 {
-  if (c < 041 || c >= 0177)
+  const char *msg;
+  size_t msg_size;
+
+  if (errcode < 0
+      || errcode >= (int) (sizeof (re_error_msgid)
+			   / sizeof (re_error_msgid[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 = gettext (re_error_msgid[errcode]);
+
+  msg_size = strlen (msg) + 1; /* Includes the null.  */
+
+  if (errbuf_size != 0)
     {
-      putchar_unfiltered ('\\');
-      putchar_unfiltered (((c >> 6) & 3) + '0');
-      putchar_unfiltered (((c >> 3) & 7) + '0');
-      putchar_unfiltered ((c & 7) + '0');
+      if (msg_size > errbuf_size)
+        {
+#if defined HAVE_MEMPCPY || defined _LIBC
+	  *((char *) __mempcpy (errbuf, msg, errbuf_size - 1)) = '\0';
+#else
+          memcpy (errbuf, msg, errbuf_size - 1);
+          errbuf[errbuf_size - 1] = 0;
+#endif
+        }
+      else
+        memcpy (errbuf, msg, msg_size);
     }
-  else
-    putchar_unfiltered (c);
+
+  return msg_size;
 }
+#ifdef _LIBC
+weak_alias (__regerror, regerror)
+#endif
+
 
-error (string)
-     char *string;
+/* Free dynamically allocated space used by PREG.  */
+
+void
+regfree (preg)
+    regex_t *preg;
 {
-  puts_unfiltered (string);
-  exit (1);
+  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;
 }
+#ifdef _LIBC
+weak_alias (__regfree, regfree)
+#endif
 
-#endif /* test */
+#endif /* not emacs  */