Modules/pypcre.c

/*************************************************
*      Perl-Compatible Regular Expressions       *
*************************************************/

/*   DO NOT EDIT THIS FILE! */

/* This file is automatically written by the merge-files.py script
included with the PCRE distribution for Python; it's produced from
several C files, and code is removed in the process.  If you want to
modify the code or track down bugs, it will be much easier to work
with the code in its original, multiple-file form.  Don't edit this
file by hand, or submit patches to it.

The Python-specific PCRE distribution can be retrieved from
       http://starship.skyport.net/crew/amk/regex/

The unmodified original PCRE distribution doesn't have a fixed URL
yet; write Philip Hazel <ph10@cam.ac.uk> for the latest version.

Written by:  Philip Hazel <ph10@cam.ac.uk>

Extensively modified by the Python String-SIG: <string-sig@python.org>
Send bug reports to:                           <string-sig@python.org>
(They'll figure out if it's a bug in PCRE or in the Python-specific
changes.)

           Copyright (c) 1997 University of Cambridge

-----------------------------------------------------------------------------
Permission is granted to anyone to use this software for any purpose on any
computer system, and to redistribute it freely, subject to the following
restrictions:

1. This software 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.

2. The origin of this software must not be misrepresented, either by
   explicit claim or by omission.

3. Altered versions must be plainly marked as such, and must not be
   misrepresented as being the original software.
-----------------------------------------------------------------------------
*/


#define FOR_PYTHON
#include "pcre-internal.h"
#include "Python.h"
#include "graminit.h"

/*************************************************
*      Perl-Compatible Regular Expressions       *
*************************************************/

/* This file is automatically written by the makechartables auxiliary 
program. If you edit it by hand, you might like to edit the Makefile to 
prevent its ever being regenerated. */

/* This table is a lower casing table. */

unsigned char pcre_lcc[] = {
    0,  1,  2,  3,  4,  5,  6,  7,
    8,  9, 10, 11, 12, 13, 14, 15,
   16, 17, 18, 19, 20, 21, 22, 23,
   24, 25, 26, 27, 28, 29, 30, 31,
   32, 33, 34, 35, 36, 37, 38, 39,
   40, 41, 42, 43, 44, 45, 46, 47,
   48, 49, 50, 51, 52, 53, 54, 55,
   56, 57, 58, 59, 60, 61, 62, 63,
   64, 97, 98, 99,100,101,102,103,
  104,105,106,107,108,109,110,111,
  112,113,114,115,116,117,118,119,
  120,121,122, 91, 92, 93, 94, 95,
   96, 97, 98, 99,100,101,102,103,
  104,105,106,107,108,109,110,111,
  112,113,114,115,116,117,118,119,
  120,121,122,123,124,125,126,127,
  128,129,130,131,132,133,134,135,
  136,137,138,139,140,141,142,143,
  144,145,146,147,148,149,150,151,
  152,153,154,155,156,157,158,159,
  160,161,162,163,164,165,166,167,
  168,169,170,171,172,173,174,175,
  176,177,178,179,180,181,182,183,
  184,185,186,187,188,189,190,191,
  192,193,194,195,196,197,198,199,
  200,201,202,203,204,205,206,207,
  208,209,210,211,212,213,214,215,
  216,217,218,219,220,221,222,223,
  224,225,226,227,228,229,230,231,
  232,233,234,235,236,237,238,239,
  240,241,242,243,244,245,246,247,
  248,249,250,251,252,253,254,255 };

/* This table is an upper casing table. */

unsigned char pcre_ucc[] = {
    0,  1,  2,  3,  4,  5,  6,  7,
    8,  9, 10, 11, 12, 13, 14, 15,
   16, 17, 18, 19, 20, 21, 22, 23,
   24, 25, 26, 27, 28, 29, 30, 31,
   32, 33, 34, 35, 36, 37, 38, 39,
   40, 41, 42, 43, 44, 45, 46, 47,
   48, 49, 50, 51, 52, 53, 54, 55,
   56, 57, 58, 59, 60, 61, 62, 63,
   64, 65, 66, 67, 68, 69, 70, 71,
   72, 73, 74, 75, 76, 77, 78, 79,
   80, 81, 82, 83, 84, 85, 86, 87,
   88, 89, 90, 91, 92, 93, 94, 95,
   96, 65, 66, 67, 68, 69, 70, 71,
   72, 73, 74, 75, 76, 77, 78, 79,
   80, 81, 82, 83, 84, 85, 86, 87,
   88, 89, 90,123,124,125,126,127,
  128,129,130,131,132,133,134,135,
  136,137,138,139,140,141,142,143,
  144,145,146,147,148,149,150,151,
  152,153,154,155,156,157,158,159,
  160,161,162,163,164,165,166,167,
  168,169,170,171,172,173,174,175,
  176,177,178,179,180,181,182,183,
  184,185,186,187,188,189,190,191,
  192,193,194,195,196,197,198,199,
  200,201,202,203,204,205,206,207,
  208,209,210,211,212,213,214,215,
  216,217,218,219,220,221,222,223,
  224,225,226,227,228,229,230,231,
  232,233,234,235,236,237,238,239,
  240,241,242,243,244,245,246,247,
  248,249,250,251,252,253,254,255 };

/* This table identifies various classes of character by individual bits:
    1   white space character
    2   decimal digit
    4   hexadecimal digit
    8   alphanumeric or '_'
   16   octal digit
  128   regular expression metacharacter or binary zero
*/

unsigned char pcre_ctypes[] = {
  0x80,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /*   0-  7 */
  0x00,0x01,0x01,0x01,0x01,0x01,0x00,0x00, /*   8- 15 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /*  16- 23 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /*  24- 31 */
  0x01,0x00,0x00,0x00,0x80,0x00,0x00,0x00, /*    - '  */
  0x80,0x80,0x80,0x80,0x00,0x00,0x80,0x00, /*  ( - /  */
  0x1e,0x1e,0x1e,0x1e,0x1e,0x1e,0x1e,0x1e, /*  0 - 7  */
  0x0e,0x0e,0x00,0x00,0x00,0x00,0x00,0x80, /*  8 - ?  */
  0x00,0x0c,0x0c,0x0c,0x0c,0x0c,0x0c,0x08, /*  @ - G  */
  0x08,0x08,0x08,0x08,0x08,0x08,0x08,0x08, /*  H - O  */
  0x08,0x08,0x08,0x08,0x08,0x08,0x08,0x08, /*  P - W  */
  0x08,0x08,0x08,0x80,0x00,0x00,0x80,0x08, /*  X - _  */
  0x00,0x0c,0x0c,0x0c,0x0c,0x0c,0x0c,0x08, /*  ` - g  */
  0x08,0x08,0x08,0x08,0x08,0x08,0x08,0x08, /*  h - o  */
  0x08,0x08,0x08,0x08,0x08,0x08,0x08,0x08, /*  p - w  */
  0x08,0x08,0x08,0x80,0x80,0x00,0x00,0x00, /*  x -127 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 128-135 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 136-143 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 144-151 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 152-159 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 160-167 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 168-175 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 176-183 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 184-191 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 192-199 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 200-207 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 208-215 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 216-223 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 224-231 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 232-239 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 240-247 */
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};/* 248-255 */

/* End of pcre-chartables.c */
/*************************************************
*      Perl-Compatible Regular Expressions       *
*************************************************/

/*
This is a library of functions to support regular expressions whose syntax
and semantics are as close as possible to those of the Perl 5 language.

Written by: Philip Hazel <ph10@cam.ac.uk>

           Copyright (c) 1997 University of Cambridge

-----------------------------------------------------------------------------
Permission is granted to anyone to use this software for any purpose on any
computer system, and to redistribute it freely, subject to the following
restrictions:

1. This software 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.

2. The origin of this software must not be misrepresented, either by
   explicit claim or by omission.

3. Altered versions must be plainly marked as such, and must not be
   misrepresented as being the original software.
-----------------------------------------------------------------------------

See the file Tech.Notes for some information on the internals.
*/

/* This module contains the actual definition of global variables that are
shared between the different modules. In fact, these are limited to the
indirections for memory management functions. */

/* Include the internals header, which itself includes Standard C headers plus
the external pcre header. */


/* Store get and free functions. */

void *(*pcre_malloc)(size_t) = malloc;
void  (*pcre_free)(void *) = free;

/* End of pcre-globals.c */
/*************************************************
*      Perl-Compatible Regular Expressions       *
*************************************************/

/*
This is a library of functions to support regular expressions whose syntax
and semantics are as close as possible to those of the Perl 5 language. See
the file Tech.Notes for some information on the internals.

Written by: Philip Hazel <ph10@cam.ac.uk>

           Copyright (c) 1997 University of Cambridge

-----------------------------------------------------------------------------
Permission is granted to anyone to use this software for any purpose on any
computer system, and to redistribute it freely, subject to the following
restrictions:

1. This software 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.

2. The origin of this software must not be misrepresented, either by
   explicit claim or by omission.

3. Altered versions must be plainly marked as such, and must not be
   misrepresented as being the original software.
-----------------------------------------------------------------------------
*/


/* Include the internals header, which itself includes Standard C headers plus
the external pcre header. */



/* Character types for class type bits */

static char class_types[] = { ctype_digit, ctype_space, ctype_word };



/*************************************************
*         Set a range of bits in the map         *
*************************************************/

/* This function is called for character types.

Arguments:
  start_bits    points to the bit map
  type          a character type bit
  include       TRUE to include the type;
                FALSE to include all but the type

Returns:        nothing
*/

static void
set_type_bits(uschar *start_bits, int type, BOOL include)
{
int i;
for (i = 0; i < 256; i++)
  if (((pcre_ctypes[i] & type) != 0) == include) start_bits[i/8] |= (1<<(i%8));
}



/*************************************************
*          Set one bit in the map                *
*************************************************/

/* This function is called to set a bit in the map for a given character,
or both cases of a letter if caseless. It could be replaced by a macro if
better performance is wanted.

Arguments:
  start_bits   points to 32-byte table
  c            the character
  caseless     TRUE if caseless

Returns:       nothing
*/

static void
set_bit(uschar *start_bits, int c, BOOL caseless)
{
if (caseless)
  {
  int d = pcre_ucc[c];
  start_bits[d/8] |= (1<<(d%8));
  c = pcre_lcc[c];
  }
start_bits[c/8] |= (1<<(c%8));
}



/*************************************************
*          Create bitmap of starting chars       *
*************************************************/

/* This function scans a compiled unanchored expression and attempts to build a
bitmap of the set of initial characters. If it can't, it returns FALSE. As time
goes by, we may be able to get more clever at doing this.

Arguments:
  code         points to an expression
  start_bits   points to a 32-byte table, initialized to 0
  caseless     TRUE if caseless

Returns:       TRUE if table built, FALSE otherwise
*/

static BOOL
set_start_bits(uschar *code, uschar *start_bits, BOOL caseless)
{
do
  {
  uschar *tcode = code + 3;
  BOOL try_next = TRUE;

  while (try_next)
    {
    try_next = FALSE;

    if ((int)*tcode >= OP_BRA || *tcode == OP_ASSERT)
      {
      if (!set_start_bits(tcode, start_bits, caseless)) return FALSE;
      }

    else switch(*tcode)
      {
      default:
      return FALSE;

      /* BRAZERO does the bracket, but carries on. */

      case OP_BRAZERO:
      case OP_BRAMINZERO:
      if (!set_start_bits(++tcode, start_bits, caseless)) return FALSE;
      do tcode += (tcode[1] << 8) + tcode[2]; while (*tcode == OP_ALT);
      tcode += 3;
      try_next = TRUE;
      break;

      /* Single-char * or ? sets the bit and tries the next item */

      case OP_STAR:
      case OP_MINSTAR:
      case OP_QUERY:
      case OP_MINQUERY:
      set_bit(start_bits, tcode[1], caseless);
      tcode += 2;
      try_next = TRUE;
      break;

      /* Single-char upto sets the bit and tries the next */

      case OP_UPTO:
      case OP_MINUPTO:
      set_bit(start_bits, tcode[3], caseless);
      tcode += 4;
      try_next = TRUE;
      break;

      /* At least one single char sets the bit and stops */

      case OP_EXACT:       /* Fall through */
      tcode++;

      case OP_CHARS:       /* Fall through */
      tcode++;

      case OP_PLUS:
      case OP_MINPLUS:
      set_bit(start_bits, tcode[1], caseless);
      break;

      /* Single character type sets the bits and stops */

      case OP_NOT_DIGIT:
      set_type_bits(start_bits, ctype_digit, FALSE);
      break;

      case OP_DIGIT:
      set_type_bits(start_bits, ctype_digit, TRUE);
      break;

      case OP_NOT_WHITESPACE:
      set_type_bits(start_bits, ctype_space, FALSE);
      break;

      case OP_WHITESPACE:
      set_type_bits(start_bits, ctype_space, TRUE);
      break;

      case OP_NOT_WORDCHAR:
      set_type_bits(start_bits, ctype_word, FALSE);
      break;

      case OP_WORDCHAR:
      set_type_bits(start_bits, ctype_word, TRUE);
      break;

      /* One or more character type fudges the pointer and restarts, knowing
      it will hit a single character type and stop there. */

      case OP_TYPEPLUS:
      case OP_TYPEMINPLUS:
      tcode++;
      try_next = TRUE;
      break;

      case OP_TYPEEXACT:
      tcode += 3;
      try_next = TRUE;
      break;

      /* Zero or more repeats of character types set the bits and then
      try again. */

      case OP_TYPEUPTO:
      case OP_TYPEMINUPTO:
      tcode += 2;               /* Fall through */

      case OP_TYPESTAR:
      case OP_TYPEMINSTAR:
      case OP_TYPEQUERY:
      case OP_TYPEMINQUERY:
      switch(tcode[1])
        {
        case OP_NOT_DIGIT:
        set_type_bits(start_bits, ctype_digit, FALSE);
        break;

        case OP_DIGIT:
        set_type_bits(start_bits, ctype_digit, TRUE);
        break;

        case OP_NOT_WHITESPACE:
        set_type_bits(start_bits, ctype_space, FALSE);
        break;

        case OP_WHITESPACE:
        set_type_bits(start_bits, ctype_space, TRUE);
        break;

        case OP_NOT_WORDCHAR:
        set_type_bits(start_bits, ctype_word, FALSE);
        break;

        case OP_WORDCHAR:
        set_type_bits(start_bits, ctype_word, TRUE);
        break;
        }

      tcode += 2;
      try_next = TRUE;
      break;

      /* Character class: set the bits and either carry on or not,
      according to the repeat count. */

      case OP_CLASS:
      case OP_NEGCLASS:
        {
        uschar *base = tcode;
        uschar *data, *end;
        uschar *bitmap = start_bits;
        uschar local[32];
        int flags = base[1];
        int i;

        tcode += 4 + 2 * tcode[2] + tcode[3];      /* Advance past the item */
        switch (*tcode)
          {
          case OP_CRSTAR:
          case OP_CRMINSTAR:
          case OP_CRQUERY:
          case OP_CRMINQUERY:
          tcode++;
          try_next = TRUE;
          break;

          case OP_CRRANGE:
          case OP_CRMINRANGE:
          if (((tcode[1] << 8) + tcode[2]) == 0)
            {
            tcode += 5;
            try_next = TRUE;
            }
          break;
          }

        /* For a negated class, we have to build a separate table of all
        the bits in the class, and then turn all other bits on in the main
        table. Otherwise there are problems with things like [^\da]. */

        if (*base == OP_NEGCLASS)
          {
          memset(local, 0, 32);
          bitmap = local;
          }

        /* Character types */

        for (i = 0; flags != 0; i++)
          {
          if ((flags & 1) != 0)
            set_type_bits(bitmap, class_types[i/2], (i & 1) == 0);
          flags >>= 1;
          }

        /* Ranges and individual characters */

        data = base + 4;
        end = data + base[2] * 2;
        while (data < end)
          {
          for (i = *data; i <= data[1]; i++) set_bit(bitmap, i, caseless);
          data += 2;
          }

        end += base[3];
        while (data < end) set_bit(bitmap, *data++, caseless);

        /* If a negated class, transfer data from local map to the main one */

        if (bitmap != start_bits)
          for (i = 0; i < 32; i++) start_bits[i] |= ~local[i];
        }
      break; /* End of class handling */

      }      /* End of switch */
    }        /* End of try_next loop */

  code += (code[1] << 8) + code[2];   /* Advance to next branch */
  }
while (*code == OP_ALT);
return TRUE;
}



/*************************************************
*          Study a compiled expression           *
*************************************************/

/* This function is handed a compiled expression that it must study to produce
information that will speed up the matching. It returns a pcre_extra block
which then gets handed back to pcre_exec().

Arguments:
  re        points to the compiled expression
  options   contains option bits
  errorptr  points to where to place error messages;
            set NULL unless error

Returns:    pointer to a pcre_extra block,
            NULL on error or if no optimization possible
*/

pcre_extra *
pcre_study(pcre *external_re, int options, char **errorptr)
{
BOOL caseless;
uschar start_bits[32];
real_pcre_extra *extra;
real_pcre *re = (real_pcre *)external_re;

*errorptr = NULL;

if (re == NULL || re->magic_number != MAGIC_NUMBER)
  {
  *errorptr = "argument is not a compiled regular expression";
  return NULL;
  }

if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
  {
  *errorptr = "unknown or incorrect option bit(s) set";
  return NULL;
  }

/* For an anchored pattern, or an unchored pattern that has a first char, or a
multiline pattern that matches only at "line starts", no further processing at
present. */

if ((re->options & (PCRE_ANCHORED|PCRE_FIRSTSET|PCRE_STARTLINE)) != 0)
  return NULL;

/* Determine the caseless state from the compiled pattern and the current
options. */

caseless = ((re->options | options) & PCRE_CASELESS) != 0;

/* See if we can find a fixed set of initial characters for the pattern. */

memset(start_bits, 0, 32);
if (!set_start_bits(re->code, start_bits, caseless)) return NULL;

/* Get an "extra" block and put the information therein. */

extra = (real_pcre_extra *)(pcre_malloc)(sizeof(real_pcre_extra));

if (extra == NULL)
  {
  *errorptr = "failed to get memory";
  return NULL;
  }
extra->options = PCRE_STUDY_MAPPED | (caseless? PCRE_STUDY_CASELESS : 0);
memcpy(extra->start_bits, start_bits, 32);

return (pcre_extra *)extra;
}

/* End of pcre-study.c */
/*************************************************
*      Perl-Compatible Regular Expressions       *
*************************************************/

/*
This is a library of functions to support regular expressions whose syntax
and semantics are as close as possible to those of the Perl 5 language. See
the file Tech.Notes for some information on the internals.

Written by: Philip Hazel <ph10@cam.ac.uk>

           Copyright (c) 1997 University of Cambridge

-----------------------------------------------------------------------------
Permission is granted to anyone to use this software for any purpose on any
computer system, and to redistribute it freely, subject to the following
restrictions:

1. This software 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.

2. The origin of this software must not be misrepresented, either by
   explicit claim or by omission.

3. Altered versions must be plainly marked as such, and must not be
   misrepresented as being the original software.
-----------------------------------------------------------------------------
*/


/* Define DEBUG to get debugging output on stdout. */

/* #define DEBUG */


/* Include the internals header, which itself includes Standard C headers plus
the external pcre header. */


#ifndef Py_eval_input
/* For Python 1.4, graminit.h has to be explicitly included */
#define Py_eval_input eval_input
#endif

/* Min and max values for the common repeats; for the maxima, 0 => infinity */

static char rep_min[] = { 0, 0, 1, 1, 0, 0 };
static char rep_max[] = { 0, 0, 0, 0, 1, 1 };

/* Text forms of OP_ values and things, for debugging */

#ifdef DEBUG
static char *OP_names[] = { "End", "\\A", "\\B", "\\b", "\\D", "\\d",
  "\\S", "\\s", "\\W", "\\w", "\\Z", "^", "$", "Any", "chars",
  "*", "*?", "+", "+?", "?", "??", "{", "{", "{",
  "*", "*?", "+", "+?", "?", "??", "{", "{", "{",
  "*", "*?", "+", "+?", "?", "??", "{", "{",
  "class", "negclass", "Ref",
  "Alt", "Ket", "KetRmax", "KetRmin", "Assert", "Assert not",
  "Brazero", "Braminzero", "Bra"
};

static char *class_names[] = { "\\d", "\\D", "\\s", "\\S", "\\w", "\\W" };
#endif

/* Table of character type operators that correspond to the bits in the
character class flags, starting at the least significant end. */

static char class_ops[] = {
  OP_DIGIT, OP_NOT_DIGIT,
  OP_WHITESPACE, OP_NOT_WHITESPACE,
  OP_WORDCHAR, OP_NOT_WORDCHAR };

/* Table for handling escaped characters in the range '0'-'z'. Positive returns
are simple data values; negative values are for special things like \d and so
on. Zero means further processing is needed (for things like \x), or the escape
is invalid. */

/* PYTHON: Python doesn't support \e, but does support \v */

static short int escapes[] = {
    0,      0,      0,      0,      0,      0,      0,      0,   /* 0 - 7 */
    0,      0,    ':',    ';',    '<',    '=',    '>',    '?',   /* 8 - ? */
  '@', -ESC_A, -ESC_B,      0, -ESC_D,      0,      0,      0,   /* @ - G */
    0,      0,      0,      0,      0,      0,      0,      0,   /* H - O */
    0,      0,      0, -ESC_S,      0,      0,      0, -ESC_W,   /* P - W */
    0,      0, -ESC_Z,    '[',   '\\',    ']',    '^',    '_',   /* X - _ */
  '`',      7, -ESC_b,      0, -ESC_d,      0,   '\f',      0,   /* ` - g */
    0,      0,      0,      0,      0,      0,   '\n',      0,   /* h - o */
    0,      0,   '\r', -ESC_s,   '\t',      0,   '\v', -ESC_w,   /* p - w */
    0,      0,      0                                            /* x - z */
};


/* Definition to allow mutual recursion */

static BOOL compile_regexp(BOOL, int *, uschar **, uschar **, 
			   char **, PyObject *);

/* Structure for passing "static" information around between the functions
doing the matching, so that they are thread-safe. */

typedef struct match_data {
  int    errorcode;             /* As it says */
  int   *offset_vector;         /* Offset vector */
  int    offset_end;            /* One past the end */
  BOOL   offset_overflow;       /* Set if too many extractions */
  BOOL   caseless;              /* Case-independent flag */
  BOOL   multiline;             /* Multiline flag */
  uschar *start_subject;        /* Start of the subject string */
  uschar *end_subject;          /* End of the subject string */

  uschar *end_match_ptr;        /* Subject position at end match */
  int     end_offset_top;       /* Highwater mark at end of match */
  BOOL   dotall;                /* Dotall flag */
  int    length;                /* Length of the allocated stacks */
  int    point;                 /* Point to add next item pushed onto stacks */
  /* Pointers to the 6 stacks */
  int *off_num, *offset_top, *r1, *r2; 
  uschar **eptr, **ecode; 
} match_data;



/*************************************************
*          Return version string                 *
*************************************************/

char *
pcre_version(void)
{
return PCRE_VERSION;
}




/*************************************************
*       Return info about a compiled pattern     *
*************************************************/

/* This function picks potentially useful data out of the private
structure.

Arguments:
  external_re   points to compiled code
  optptr        where to pass back the options
  first_char    where to pass back the first character,
                or -1 if multiline and all branches start ^,
                or -2 otherwise

Returns:        number of identifying extraction brackets
                or negative values on error
*/

int
pcre_info(pcre *external_re, int *optptr, int *first_char)
{
real_pcre *re = (real_pcre *)external_re;
if (re == NULL) return PCRE_ERROR_NULL;
if (re->magic_number != MAGIC_NUMBER) return PCRE_ERROR_BADMAGIC;
if (optptr != NULL) *optptr = (re->options & PUBLIC_OPTIONS);
if (first_char != NULL)
  *first_char = ((re->options & PCRE_FIRSTSET) != 0)? re->first_char :
     ((re->options & PCRE_STARTLINE) != 0)? -1 : -2;
return re->top_bracket;
}




#ifdef DEBUG
/*************************************************
*        Debugging function to print chars       *
*************************************************/

/* Print a sequence of chars in printable format, stopping at the end of the
subject if the requested.

Arguments:
  p           points to characters
  length      number to print
  is_subject  TRUE if printing from within md->start_subject
  md          pointer to matching data block, if is_subject is TRUE

Returns:     nothing
*/

static pchars(uschar *p, int length, BOOL is_subject, match_data *md)
{
int c;
if (is_subject && length > md->end_subject - p) length = md->end_subject - p;
while (length-- > 0)
  if (isprint(c = *(p++))) printf("%c", c); else printf("\\x%02x", c);
}
#endif




/*************************************************
*         Check subpattern for empty operand     *
*************************************************/

/* This function checks a bracketed subpattern to see if any of the paths
through it could match an empty string. This is used to diagnose an error if
such a subpattern is followed by a quantifier with an unlimited upper bound.

Argument:
  code      points to the opening bracket

Returns:    TRUE or FALSE
*/

static BOOL
could_be_empty(uschar *code)
{
do {
  uschar *cc = code + 3;

  /* Scan along the opcodes for this branch; as soon as we find something
  that matches a non-empty string, break out and advance to test the next
  branch. If we get to the end of the branch, return TRUE for the whole
  sub-expression. */

  for (;;)
    {
    /* Test an embedded subpattern; if it could not be empty, break the
    loop. Otherwise carry on in the branch. */

    if ((int)(*cc) >= OP_BRA)
      {
      if (!could_be_empty(cc)) break;
      do cc += (cc[1] << 8) + cc[2]; while (*cc == OP_ALT);
      cc += 3;
      }

    else switch (*cc)
      {
      /* Reached end of a branch: the subpattern may match the empty string */

      case OP_ALT:
      case OP_KET:
      case OP_KETRMAX:
      case OP_KETRMIN:
      return TRUE;

      /* Skip over assertive subpatterns */

      case OP_ASSERT:
      case OP_ASSERT_NOT:
      do cc += (cc[1] << 8) + cc[2]; while (*cc == OP_ALT);
      cc += 3;
      break;

      /* Skip over things that don't match chars */

      case OP_SOD:
      case OP_EOD:
      case OP_CIRC:
      case OP_DOLL:
      case OP_BRAZERO:
      case OP_BRAMINZERO:
      case OP_NOT_WORD_BOUNDARY:
      case OP_WORD_BOUNDARY:
      cc++;
      break;

      /* Skip over simple repeats with zero lower bound */

      case OP_STAR:
      case OP_MINSTAR:
      case OP_QUERY:
      case OP_MINQUERY:
      case OP_TYPESTAR:
      case OP_TYPEMINSTAR:
      case OP_TYPEQUERY:
      case OP_TYPEMINQUERY:
      cc += 2;
      break;

      /* Skip over UPTOs (lower bound is zero) */

      case OP_UPTO:
      case OP_MINUPTO:
      case OP_TYPEUPTO:
      case OP_TYPEMINUPTO:
      cc += 4;
      break;

      /* Check a class or a back reference for a zero minimum */

      case OP_CLASS:
      case OP_NEGCLASS:
      case OP_REF:
      cc += (*cc == OP_REF)? 2 : 4 + 2 * cc[2] + cc[3];

      switch (*cc)
        {
        case OP_CRSTAR:
        case OP_CRMINSTAR:
        case OP_CRQUERY:
        case OP_CRMINQUERY:
        cc++;
        break;

        case OP_CRRANGE:
        case OP_CRMINRANGE:
        if ((cc[1] << 8) + cc[2] != 0) goto NEXT_BRANCH;
        cc += 3;
        break;

        default:
        goto NEXT_BRANCH;
        }
      break;

      /* Anything else matches at least one character */

      default:
      goto NEXT_BRANCH;
      }
    }

  NEXT_BRANCH:
  code += (code[1] << 8) + code[2];
  }
while (*code == OP_ALT);

/* No branches match the empty string */

return FALSE;
}


/* Determine the length of a group ID in an expression like
   (?P<foo_123>...) 
Arguments:
  ptr        pattern position pointer (say that 3 times fast)
  finalchar  the character that will mark the end of the ID
  errorptr   points to the pointer to the error message
*/
  
static int 
get_group_id(uschar *ptr, char finalchar, char **errorptr)
{
  uschar *start = ptr;

  /* If the first character is not in \w, or is in \w but is a digit,
     report an error */
  if (!(pcre_ctypes[*ptr] & ctype_word) ||
      (pcre_ctypes[*ptr++] & ctype_digit))
    {
      *errorptr = "(?P identifier must start with a letter or underscore";
      return 0;
    }

  /* Increment ptr until we either hit a null byte, the desired 
     final character, or a non-word character */
  for(; (*ptr != 0) && (*ptr != finalchar) && 
	(pcre_ctypes[*ptr] & ctype_word); ptr++)
    {
      /* Empty loop body */
    }
  if (*ptr==finalchar)
    return ptr-start;
  if (*ptr==0)
    {
      *errorptr = "unterminated (?P identifier";
      return 0;
    }
  *errorptr = "illegal character in (?P identifier";
  return 0;
}

/*************************************************
*            Handle escapes                      *
*************************************************/

/* This function is called when a \ has been encountered. It either returns a
positive value for a simple escape such as \n, or a negative value which
encodes one of the more complicated things such as \d. On entry, ptr is
pointing at the \. On exit, it is on the final character of the escape
sequence.

Arguments:
  ptrptr     points to the pattern position pointer
  errorptr   points to the pointer to the error message

Returns:     zero or positive => a data character
             negative => a special escape sequence
             on error, errorptr is set
*/

static int
check_escape(uschar **ptrptr, char **errorptr)
{
uschar *ptr = *ptrptr;
int c = *(++ptr) & 255;   /* Ensure > 0 on signed-char systems */
int i;

if (c == 0) *errorptr = "\\ at end of pattern";

/* Digits or letters may have special meaning; all others are literals. */

else if (c < '0' || c > 'z') {}

/* Do an initial lookup in a table. A non-zero result is something that can be
returned immediately. Otherwise further processing may be required. */

else if ((i = escapes[c - '0']) != 0) c = i;

/* Escapes that need further processing, or are illegal. */

else switch (c)
  {
  case '0':
  c = 0;
  while(i++ < 2 && (pcre_ctypes[ptr[1]] & ctype_odigit) != 0 )
      c = c * 8 + *(++ptr) - '0';
  break;

  case '1': case '2': case '3': case '4': case '5':
  case '6': case '7': case '8': case '9':
    {
      /* PYTHON: Try to compute an octal value for a character */
      for(c=0, i=0; c!=-1 && ptr[i]!=0 && i<3; i++) 
	{
	  if (( pcre_ctypes[ ptr[i] ] & ctype_odigit) != 0)
	    c = c * 8 + ptr[i]-'0';
	  else
	    c = -1; /* Non-octal character */
	}
      /* Aha!  There were 3 octal digits, so it must be a character */
      if (c != -1 && i == 3) 
	{
	  ptr += i-1;
	  break;
	}
      c = ptr[0]; /* Restore the first character after the \ */
      c -= '0'; i = 1;
      while (i<2 && (pcre_ctypes[ptr[1]] & ctype_digit) != 0)
	{
	  c = c * 10 + ptr[1] - '0'; 
	  ptr++; i++;
	}
      if (c > 255 - ESC_REF) *errorptr = "back reference too big";
      c = -(ESC_REF + c);
    }
  break;

  case 'x':
    {
      int length;
      char *string;
      PyObject *result;
      
      i=1;
      while (ptr[i]!=0 && 
	     ( pcre_ctypes[ptr[i]] & ctype_xdigit) != 0)
	i++;
      if (i==1)
	{
	  *errorptr="\\x must be followed by hex digits";
	  break;
	}
      length=i-1;
      string=malloc(length+4+1);
      if (string==NULL)
	{
	  *errorptr="can't allocate memory for \\x string";
	  break;
	}
      /* Create a string containing "\x<hexdigits>", which will be
	 passed to eval() */
      string[0]=string[length+3]='"';
      string[1]='\\';
      string[length+4]='\0';
      memcpy(string+2, ptr, length+1);
      ptr += length;
      result=PyRun_String((char *)string, Py_eval_input, 
			  PyEval_GetGlobals(), PyEval_GetLocals());
      free(string);
      /* The evaluation raised an exception */
      if (result==NULL) 
	{
	  *errorptr="exception occurred during evaluation of \\x";
	  break;
	}
      if (PyString_Size(result)!=1)
	{
	  Py_DECREF(result);
	  *errorptr="\\x string is not one byte in length";
	  break;
	}
      c=*(unsigned char *)PyString_AsString(result);
      Py_DECREF(result);
      break;
    }
  break;


  case 'l':
  case 'L':
  case 'u':
  case 'U':
  case 'Q':
  case 'E':
  *errorptr = "the Perl escapes \\u, \\U, \\l, \\L, \\Q, \\E are not valid";
  break;

  default:
    /* In Python, an unrecognized escape will simply return the character 
       after the backslash, so do nothing */
  break;
  }

*ptrptr = ptr;
return c;
}



/*************************************************
*         Read repeat counts                     *
*************************************************/

/* Read an item of the form {n,m} and return the values.

Arguments:
  p          pointer to first char after '{'
  minp       pointer to int for min
  maxp       pointer to int for max
             returned as -1 if no max
  errorptr   points to pointer to error message

Returns:     pointer to '}' on success;
             current ptr on error, with errorptr set
*/

static uschar *
read_repeat_counts(uschar *p, int *minp, int *maxp, char **errorptr)
{
int min = 0;
int max = -1;

if ((pcre_ctypes[*p] & ctype_digit) == 0)
  {
  *errorptr = "number expected after {";
  return p;
  }

while ((pcre_ctypes[*p] & ctype_digit) != 0) min = min * 10 + *p++ - '0';

if (*p == '}') max = min; else
  {
  if (*p++ != ',')
    {
    *errorptr = "comma expected";
    return p-1;
    }
  if (*p != '}')
    {
    max = 0;
    while((pcre_ctypes[*p] & ctype_digit) != 0) max = max * 10 + *p++ - '0';
    if (*p != '}')
      {
      *errorptr = "} expected";
      return p;
      }
    if (max < min)
      {
      *errorptr = "numbers out of order";
      return p;
      }
    }
  }

/* Do paranoid checks, then fill in the required variables, and pass back the
pointer to the terminating '}'. */

if (max == 0) *errorptr = "zero maximum not allowed";
else if (min > 65535 || max > 65535) *errorptr = "number too big";
else
  {
  *minp = min;
  *maxp = max;
  }
return p;
}



/*************************************************
*           Compile one branch                   *
*************************************************/

/* Scan the pattern, compiling it into the code vector.

Arguments:
  extended   TRUE if the PCRE_EXTENDED option was set
  brackets   points to 2-element bracket vector
  code       points to the pointer to the current code point
  ptrptr     points to the current pattern pointer
  errorptr   points to pointer to error message

Returns:     TRUE on success
             FALSE, with *errorptr set on error
*/

static BOOL
compile_branch(BOOL extended, int *brackets, uschar **codeptr,
  uschar **ptrptr, char **errorptr, PyObject *dictionary)
{
int repeat_type, op_type;
int repeat_min, repeat_max;
int bravalue, length;
register int c;
register uschar *code = *codeptr;
uschar *ptr = *ptrptr;
uschar *previous = NULL;
uschar *oldptr;

/* Switch on next character until the end of the branch */

for (;; ptr++)
  {
  c = *ptr;
  if (extended)
    {
    if ((pcre_ctypes[c] & ctype_space) != 0) continue;
    if (c == '#')
      {
      while ((c = *(++ptr)) != 0 && c != '\n');
      continue;
      }
    }

  switch(c)
    {
    /* The branch terminates at end of string, |, or ). */

    case 0:
    case '|':
    case ')':
    *codeptr = code;
    *ptrptr = ptr;
    return TRUE;

    /* Handle single-character metacharacters */

    case '^':
    previous = NULL;
    *code++ = OP_CIRC;
    break;

    case '$':
    previous = NULL;
    *code++ = OP_DOLL;
    break;

    case '.':
    previous = code;
    *code++ = OP_ANY;
    break;

    /* Character classes. We do quite a bit of munging around here. There are
    always four initial bytes: the op_code, a flags byte for things like \d, a
    count of pairs and a count of single characters. The pairs then follow, and
    finally the single characters. */

    case '[':
      {
      int rangecount = 0;
      int flags = 0;
      int singles_count = 0;
      char singles[256];

      previous = code;

      /* If the first character is '^', set the negation flag */

      if ((c = *(++ptr)) == '^') { *code = OP_NEGCLASS; c = *(++ptr); }
        else *code = OP_CLASS;
      code += 4;

      /* Process characters until ] is reached. By writing this as a "do" it
      means that an initial ] is taken as a data character. */

      do
        {
        if (c == 0)
          {
          *errorptr = "] missing";
          goto FAILED;
          }

        /*** Perl treats '-' here as a data character, so PCRE had better
        do the same ... cut out this diagnosis.

        if (c == '-')
          {
          *errorptr = "unexpected '-' in character class";
          goto FAILED;
          }
        ... ***/

        /* Backslash may introduce a single character, or it may introduce one
        of the specials, which just set a flag. Escaped items are checked for
        validity in the pre-compiling pass. The sequence \b is a special case.
        Inside a class (and only there) it is treated as backslash. Elsewhere
        it marks a word boundary. */

        if (c == '\\')
          {
	    uschar *save_ptr = ptr+1;
          c = check_escape(&ptr, errorptr);
          if (c < 0)
            {
            switch (-c)
              {
              case ESC_d: flags |= CLASS_DIGITS; continue;
              case ESC_D: flags |= CLASS_NOT_DIGITS; continue;
              case ESC_s: flags |= CLASS_WHITESPACE; continue;
              case ESC_S: flags |= CLASS_NOT_WHITESPACE; continue;
              case ESC_w: flags |= CLASS_WORD; continue;
              case ESC_W: flags |= CLASS_NOT_WORD; continue;
              default:
		ptr = save_ptr;
		c = *ptr;
		break;

              case ESC_b: c = '\b';   /* Treat as single character */
              break;
              }
            }
          /* Fall through if single character */
          }

        /* A single character may be followed by '-' to form a range. However,
        Perl does not permit ']' to be the end of the range. A '-' character
        here is treated as a literal. */

        if (ptr[1] == '-' && ptr[2] != ']')
          {
          int d;
          ptr += 2;
          d = *ptr;

          if (d == 0)
            {
            *errorptr = "incomplete range";
            goto FAILED;
            }

          /* The second part of a range can be a single-character escape, but
          not any of the other escapes. */

          if (d == '\\')
            {
            d = check_escape(&ptr, errorptr);
            if (d < 0)
              {
              if (d == -ESC_b) d = '\b'; else
                {
                *errorptr = "invalid range";
                goto FAILED;
                }
              }
            }

          if (d < c)
            {
            *errorptr = "range out of order";
            goto FAILED;
            }

          if (rangecount >= 255)
            {
            *errorptr = "too many ranges inside []";
            goto FAILED;
            }

          rangecount++;
          *code++ = c;
          *code++ = d;
          continue;
          }

        /* Handle a lone single character: save it up for outputting at the
        end. Be paranoid and check that the buffer isn't going to overflow. */

        if (singles_count >= 255)
          {
          *errorptr = "too many characters inside []";
          goto FAILED;
          }
        singles[singles_count++] = c;
        }

      /* Loop until ']' reached; the check for end of string happens inside the
      loop. This "while" is the end of the "do" above. */

      while ((c = *(++ptr)) != ']');

      /* Copy saved single characters, which follow the ranges in the output. */

      c = 0;      
      while (c < singles_count) *code++ = singles[c++];

      /* Finally fill in the flags and counts of ranges and single characters,
      and advance the pointer past the ]. */

      previous[1] = flags;
      previous[2] = rangecount;
      previous[3] = singles_count;
      }
    break;

    /* Various kinds of repeat */

    case '{':
    ptr = read_repeat_counts(ptr+1, &repeat_min, &repeat_max, errorptr);
    if (*errorptr != NULL) goto FAILED;
    goto REPEAT;

    case '*':
    repeat_min = 0;
    repeat_max = -1;
    goto REPEAT;

    case '+':
    repeat_min = 1;
    repeat_max = -1;
    goto REPEAT;

    case '?':
    repeat_min = 0;
    repeat_max = 1;

    REPEAT:
    if (previous == NULL)
      {
      *errorptr = "nothing to repeat";
      goto FAILED;
      }

    /* If the next character is '?' this is a minimizing repeat. Advance to the
    next character. */

    if (ptr[1] == '?') { repeat_type = 1; ptr++; } else repeat_type = 0;

    /* If previous was a string of characters, chop off the last one and use it
    as the subject of the repeat. If there was only one character, we can
    abolish the previous item altogether. */

    if (*previous == OP_CHARS)
      {
      int len = previous[1];
      if (len == 1)
        {
        c = previous[2];
        code = previous;
        }
      else
        {
        c = previous[len+1];
        previous[1]--;
        code--;
        }
      op_type = 0;                 /* Use single-char op codes */
      goto OUTPUT_SINGLE_REPEAT;   /* Code shared with single character types */
      }

    /* If previous was a character type match (\d or similar), abolish it and
    create a suitable repeat item. The code is shared with single-character
    repeats by adding a suitable offset into repeat_type. */

    if ((int)*previous < OP_EOD || *previous == OP_ANY)
      {
      op_type = OP_TYPESTAR - OP_STAR;  /* Use type opcodes */
      c = *previous;
      code = previous;

      OUTPUT_SINGLE_REPEAT:
      repeat_type += op_type;      /* Combine both values for many cases */

      /* A minimum of zero is handled either as the special case * or ?, or as
      an UPTO, with the maximum given. */

      if (repeat_min == 0)
        {
        if (repeat_max == -1) *code++ = OP_STAR + repeat_type;
          else if (repeat_max == 1) *code++ = OP_QUERY + repeat_type;
        else
          {
          *code++ = OP_UPTO + repeat_type;
          *code++ = repeat_max >> 8;
          *code++ = (repeat_max & 255);
          }
        }

      /* The case {1,} is handled as the special case + */

      else if (repeat_min == 1 && repeat_max == -1)
        *code++ = OP_PLUS + repeat_type;

      /* The case {n,n} is just an EXACT, while the general case {n,m} is
      handled as an EXACT followed by an UPTO. An EXACT of 1 is optimized. */

      else
        {
        if (repeat_min != 1)
          {
          *code++ = OP_EXACT + op_type;  /* NB EXACT doesn't have repeat_type */
          *code++ = repeat_min >> 8;
          *code++ = (repeat_min & 255);
          }

        /* If the mininum is 1 and the previous item was a character string,
        we either have to put back the item that got cancelled if the string
        length was 1, or add the character back onto the end of a longer
        string. For a character type nothing need be done; it will just get put
        back naturally. */

        else if (*previous == OP_CHARS)
          {
          if (code == previous) code += 2; else previous[1]++;
          }

        /* Insert an UPTO if the max is greater than the min. */

        if (repeat_max != repeat_min)
          {
          *code++ = c;
          repeat_max -= repeat_min;
          *code++ = OP_UPTO + repeat_type;
          *code++ = repeat_max >> 8;
          *code++ = (repeat_max & 255);
          }
        }

      /* The character or character type itself comes last in all cases. */

      *code++ = c;
      }

    /* If previous was a character class or a back reference, we put the repeat
    stuff after it. */

    else if (*previous == OP_CLASS || *previous == OP_NEGCLASS ||
             *previous == OP_REF)
      {
      if (repeat_min == 0 && repeat_max == -1)
        *code++ = OP_CRSTAR + repeat_type;
      else if (repeat_min == 1 && repeat_max == -1)
        *code++ = OP_CRPLUS + repeat_type;
      else if (repeat_min == 0 && repeat_max == 1)
        *code++ = OP_CRQUERY + repeat_type;
      else
        {
        *code++ = OP_CRRANGE + repeat_type;
        *code++ = repeat_min >> 8;
        *code++ = repeat_min & 255;
        if (repeat_max == -1) repeat_max = 0;  /* 2-byte encoding for max */
        *code++ = repeat_max >> 8;
        *code++ = repeat_max & 255;
        }
      }

    /* If previous was a bracket group, we may have to replicate it in certain
    cases. If the maximum repeat count is unlimited, check that the bracket
    group cannot match the empty string, and diagnose an error if it can. */

    else if ((int)*previous >= OP_BRA)
      {
      int i;
      int length = code - previous;

      if (repeat_max == -1 && could_be_empty(previous))
        {
        *errorptr = "operand of unlimited repeat could match the empty string";
        goto FAILED;
        }

      /* If the minimum is greater than zero, and the maximum is unlimited or
      equal to the minimum, the first copy remains where it is, and is
      replicated up to the minimum number of times. This case includes the +
      repeat, but of course no replication is needed in that case. */

      if (repeat_min > 0 && (repeat_max == -1 || repeat_max == repeat_min))
        {
        for (i = 1; i < repeat_min; i++)
          {
          memcpy(code, previous, length);
          code += length;
          }
        }

      /* If the minimum is zero, stick BRAZERO in front of the first copy.
      Then, if there is a fixed upper limit, replicated up to that many times,
      sticking BRAZERO in front of all the optional ones. */

      else
        {
        if (repeat_min == 0)
          {
          memmove(previous+1, previous, length);
          code++;
          *previous++ = OP_BRAZERO + repeat_type;
          }

        for (i = 1; i < repeat_min; i++)
          {
          memcpy(code, previous, length);
          code += length;
          }

        for (i = (repeat_min > 0)? repeat_min : 1; i < repeat_max; i++)
          {
          *code++ = OP_BRAZERO + repeat_type;
          memcpy(code, previous, length);
          code += length;
          }
        }

      /* If the maximum is unlimited, set a repeater in the final copy. */

      if (repeat_max == -1) code[-3] = OP_KETRMAX + repeat_type;
      }

    /* Else there's some kind of shambles */

    else
      {
      *errorptr = "internal error 1 (unexpected repeat)";
      goto FAILED;
      }

    /* In all case we no longer have a previous item. */

    previous = NULL;
    break;


    /* Start of nested bracket sub-expression, or comment or lookahead.
    First deal with special things that can come after a bracket; all are
    introduced by ?, and the appearance of any of them means that this is not a
    referencing group. They were checked for validity in the first pass over
    the string, so we don't have to check for syntax errors here.  */

    case '(':
    previous = code;              /* Only real brackets can be repeated */
    if (*(++ptr) == '?')
      {
      bravalue = OP_BRA;

      switch (*(++ptr))
        {
        case '#':
        case 'i':
        case 'm':
        case 's':
        case 'x':
        ptr++;
        while (*ptr != ')') ptr++;
        previous = NULL;
        continue;

        case ':':                 /* Non-extracting bracket */
        ptr++;
        break;

        case '=':                 /* Assertions can't be repeated */
        bravalue = OP_ASSERT;
        ptr++;
        previous = NULL;
        break;

        case '!':
        bravalue = OP_ASSERT_NOT;
        ptr++;
        previous = NULL;
        break;

	case ('P'):
	  ptr++;
	  if (*ptr=='<')
	    {
	      /* (?P<groupname>...) */
	      int idlen;
	      PyObject *string, *intobj;

	      ptr++;
	      idlen = get_group_id(ptr, '>', errorptr);
	      if (*errorptr) {
		goto FAILED;
	      }
	      string = PyString_FromStringAndSize(ptr, idlen);
	      intobj = PyInt_FromLong( brackets[0] );
	      if (intobj == NULL || string==NULL)
		{
		  Py_XDECREF(string);
		  Py_XDECREF(intobj);
		  *errorptr = "exception raised";
		  goto FAILED;
		}
	      PyDict_SetItem(dictionary, string, intobj);
	      Py_DECREF(string); Py_DECREF(intobj);
	      ptr += idlen+1;  /* Point to rest of expression */
	      goto do_grouping_bracket;
	    }
	  if (*ptr=='=')
	    {
	      /* (?P=groupname) */
	      int idlen, refnum;
	      PyObject *string, *intobj;

	      ptr++;
	      idlen = get_group_id(ptr, ')', errorptr);
	      if (*errorptr) {
		goto FAILED;
	      }
	      string = PyString_FromStringAndSize(ptr, idlen);
	      if (string==NULL)	{
		  Py_XDECREF(string);
		  *errorptr = "exception raised";
		  goto FAILED;
		}
	      intobj = PyDict_GetItem(dictionary, string);
	      if (intobj==NULL) {
		Py_DECREF(string);
		*errorptr = "?P= group identifier isn't defined";
		goto FAILED;
	      }

	      refnum = PyInt_AsLong(intobj);
	      Py_DECREF(string); Py_DECREF(intobj);
	      *code++ = OP_REF;
	      *code++ = refnum;
	      /* The continue will cause the top-level for() loop to
		 be resumed, so ptr will be immediately incremented.
		 Therefore, the following line adds just idlen, not
		 idlen+1 */
	      ptr += idlen;
	      continue;
	    }
	  /* The character after ?P is neither < nor =, so 
	     report an error.  Add more Python-extensions here. */
	  *errorptr="unknown after (?P";
	  goto FAILED;
	  break;
        default:
        *errorptr = "unknown after (?";
        goto FAILED;
        }
      }

    /* Else we have a referencing group */

    else
      {
      do_grouping_bracket:
      if (brackets[0] > EXTRACT_MAX)
        {
        *errorptr = "too many extraction brackets";
        goto FAILED;
        }
      brackets[1] = brackets[0];
      bravalue = OP_BRA + brackets[0]++;
      }

    /* Process nested bracketed re; at end pointer is on the bracket. We copy
    code into a non-register variable in order to be able to pass its address
    because some compilers complain otherwise. */

    *code = bravalue;
      {
      uschar *mcode = code;
      if (!compile_regexp(extended, brackets, &mcode, &ptr, errorptr, dictionary))
        goto FAILED;
      code = mcode;
      }

    if (*ptr != ')')
      {
      *errorptr = "missing )";
      goto FAILED;
      }
    break;

    /* Check \ for being a real metacharacter; if not, fall through and handle
    it as a data character at the start of a string. Escape items are checked
    for validity in the pre-compiling pass. */

    case '\\':
    oldptr = ptr;
    c = check_escape(&ptr, errorptr);

    /* Handle metacharacters introduced by \. For ones like \d, the ESC_ values
    are arranged to be the negation of the corresponding OP_values. For the
    back references, the values are ESC_REF plus the reference number. Only
    back references and those types that consume a character may be repeated.
    We can test for values between ESC_b and ESC_Z for the latter; this may
    have to change if any new ones are ever created. */

    if (c < 0)
      {
      if (-c >= ESC_REF)
        {
        int refnum = -c -ESC_REF;
	if (brackets[1] < refnum ) {
	      *errorptr = "backreference to non-existent group";
	      goto FAILED;
	}
        previous = code;
        *code++ = OP_REF;
        *code++ = refnum;
        }
      else
        {
        previous = (-c > ESC_b && -c < ESC_Z)? code : NULL;
        *code++ = -c;
        }
      continue;
      }

    /* Reset and fall through */

    ptr = oldptr;
    c = '\\';

    /* Handle a run of data characters until a metacharacter is encountered.
    The first character is guaranteed not to be whitespace or # when the
    extended flag is set. */

    default:
    previous = code;
    *code = OP_CHARS;
    code += 2;
    length = 0;

    do
      {
      if (extended)
        {
        if ((pcre_ctypes[c] & ctype_space) != 0) continue;
        if (c == '#')
          {
          while ((c = *(++ptr)) != 0 && c != '\n');
          if (c == 0) break;
          continue;
          }
        }

      /* Backslash may introduce a data char or a metacharacter. Escaped items
      are checked for validity in the pre-compiling pass. Stop the string
      before a metaitem. */

      if (c == '\\')
        {
        oldptr = ptr;
        c = check_escape(&ptr, errorptr);
        if (c < 0) { ptr = oldptr; break; }
        }

      /* Ordinary character or single-char escape */

      *code++ = c;
      length++;
      }

    /* This "while" is the end of the "do" above. */

    while (length < 255 && (pcre_ctypes[c = *(++ptr)] & ctype_meta) == 0);

    /* Compute the length and set it in the data vector, and advance to
    the next state. */

    previous[1] = length;
    ptr--;
    break;
    }
  }                   /* end of big loop */

/* Control never reaches here by falling through, only by a goto for all the
error states. Pass back the position in the pattern so that it can be displayed
to the user for diagnosing the error. */

FAILED:
*ptrptr = ptr;
return FALSE;
}




/*************************************************
*     Compile sequence of alternatives           *
*************************************************/

/* On entry, ptr is pointing past the bracket character, but on return
it points to the closing bracket, or vertical bar, or end of string.
The code variable is pointing at the byte into which the BRA operator has been
stored.

Argument:
  extended  TRUE if PCRE_EXTENDED was set
  brackets  -> 2-element vector containing next and top bracket numbers
  codeptr   -> the address of the current code pointer
  ptrptr    -> the address of the current pattern pointer
  errorptr  -> pointer to error message

Returns:    TRUE on success
*/

static BOOL
compile_regexp(BOOL extended, int *brackets, uschar **codeptr,
  uschar **ptrptr, char **errorptr, PyObject *dictionary)
{
uschar *ptr = *ptrptr;
uschar *code = *codeptr;
uschar *start_bracket = code;

for (;;)
  {
  int length;
  uschar *last_branch = code;

  code += 3;
  if (!compile_branch(extended, brackets, &code, &ptr, errorptr, dictionary))
    {
    *ptrptr = ptr;
    return FALSE;
    }

  /* Fill in the length of the last branch */

  length = code - last_branch;
  last_branch[1] = length >> 8;
  last_branch[2] = length & 255;

  /* Reached end of expression, either ')' or end of pattern. Insert a
  terminating ket and the length of the whole bracketed item, and return,
  leaving the pointer at the terminating char. */

  if (*ptr != '|')
    {
    length = code - start_bracket;
    *code++ = OP_KET;
    *code++ = length >> 8;
    *code++ = length & 255;
    *codeptr = code;
    *ptrptr = ptr;
    return TRUE;
    }

  /* Another branch follows; insert an "or" node and advance the pointer. */

  *code = OP_ALT;
  ptr++;
  }
/* Control never reaches here */
}



/*************************************************
*          Check for anchored expression         *
*************************************************/

/* Try to find out if this is an anchored regular expression. Consider each
alternative branch. If they all start with OP_SOD or OP_CIRC, or with a bracket
all of whose alternatives start with OP_SOD or OP_CIRC (recurse ad lib), then
it's anchored. However, if this is a multiline pattern, then only OP_SOD
counts, since OP_CIRC can match in the middle.

A branch is also implicitly anchored if it starts with .* because that will try
the rest of the pattern at all possible matching points, so there is no point
trying them again.

Argument:  points to start of expression (the bracket)
Returns:   TRUE or FALSE
*/

static BOOL
is_anchored(register uschar *code, BOOL multiline)
{
do {
   int op = (int)code[3];
   if (op >= OP_BRA || op == OP_ASSERT)
     { if (!is_anchored(code+3, multiline)) return FALSE; }
   else if (op == OP_TYPESTAR || op == OP_TYPEMINSTAR)
     { if (code[4] != OP_ANY) return FALSE; }
   else if (op != OP_SOD && (multiline || op != OP_CIRC)) return FALSE;
   code += (code[1] << 8) + code[2];
   }
while (*code == OP_ALT);
return TRUE;
}



/*************************************************
*     Check for start with \n line expression    *
*************************************************/

/* This is called for multiline expressions to try to find out if every branch
starts with ^ so that "first char" processing can be done to speed things up.

Argument:  points to start of expression (the bracket)
Returns:   TRUE or FALSE
*/

static BOOL
is_startline(uschar *code)
{
do {
   if ((int)code[3] >= OP_BRA || code[3] == OP_ASSERT)
     { if (!is_startline(code+3)) return FALSE; }
   else if (code[3] != OP_CIRC) return FALSE;
   code += (code[1] << 8) + code[2];
   }
while (*code == OP_ALT);
return TRUE;
}



/*************************************************
*          Check for fixed first char            *
*************************************************/

/* Try to find out if there is a fixed first character. This is called for
unanchored expressions, as it speeds up their processing quite considerably.
Consider each alternative branch. If they all start with the same char, or with
a bracket all of whose alternatives start with the same char (recurse ad lib),
then we return that char, otherwise -1.

Argument:  points to start of expression (the bracket)
Returns:   -1 or the fixed first char
*/

static int
find_firstchar(uschar *code)
{
register int c = -1;
do
  {
  register int charoffset = 4;

  if ((int)code[3] >= OP_BRA || code[3] == OP_ASSERT)
    {
    register int d;
    if ((d = find_firstchar(code+3)) < 0) return -1;
    if (c < 0) c = d; else if (c != d) return -1;
    }

  else switch(code[3])
    {
    default:
    return -1;

    case OP_EXACT:       /* Fall through */
    charoffset++;

    case OP_CHARS:       /* Fall through */
    charoffset++;

    case OP_PLUS:
    case OP_MINPLUS:
    if (c < 0) c = code[charoffset]; else if (c != code[charoffset]) return -1;
    break;
    }
  code += (code[1] << 8) + code[2];
  }
while (*code == OP_ALT);
return c;
}



/*************************************************
*        Compile a Regular Expression            *
*************************************************/

/* This function takes a string and returns a pointer to a block of store
holding a compiled version of the expression.

Arguments:
  pattern      the regular expression
  options      various option bits
  errorptr     pointer to pointer to error text
  erroroffset  ptr offset in pattern where error was detected

Returns:       pointer to compiled data block, or NULL on error,
               with errorptr and erroroffset set
*/

pcre *
pcre_compile(char *pattern, int options, char **errorptr, int
	     *erroroffset, PyObject *dictionary)
{
real_pcre *re;
int spaces = 0;
int length = 3;      /* For initial BRA plus length */
int runlength;
int c, size;
int brackets[2];
int brastack[200];
int brastackptr = 0;
BOOL extended = (options & PCRE_EXTENDED) != 0;
uschar *code, *ptr;

#ifdef DEBUG
uschar *code_base, *code_end;
#endif

/* Miscellaneous initialization; the copy the error pointers into static
variables so all functions can access them. */

brackets[0] = 1;         /* Next bracket number */
brackets[1] = 0;         /* Highest used bracket number */

*errorptr = NULL;
*erroroffset = 0;

if ((options & ~PUBLIC_OPTIONS) != 0)
  {
  *errorptr = "unknown option bit(s) set";
  return NULL;
  }

#ifdef DEBUG
printf("------------------------------------------------------------------\n");
printf("%s\n", pattern);
#endif

/* The first thing to do is to make a pass over the pattern to compute the
amount of store required to hold the compiled code. This does not have to be
perfect as long as errors are overestimates. At the same time we can detect any
internal flag settings. Make an attempt to correct for any counted white space
if an "extended" flag setting appears late in the pattern. We can't be so
clever for #-comments. */

ptr = (uschar *)(pattern - 1);
while ((c = *(++ptr)) != 0)
  {
    int min, max;

  if ((pcre_ctypes[c] & ctype_space) != 0)
    {
    if (extended) continue;
    spaces++;
    }

  if (extended && c == '#')
    {
    while ((c = *(++ptr)) != 0 && c != '\n');
    continue;
    }

  switch(c)
    {
    /* A backslashed item may be an escaped "normal" character or a
    character type. For a "normal" character, put the pointers and
    character back so that tests for whitespace etc. in the input
    are done correctly. */

    case '\\':
      {
      uschar *save_ptr = ptr;
      c = check_escape(&ptr, errorptr);
      if (*errorptr != NULL) goto PCRE_ERROR_RETURN;
      if (c >= 0)
        {
        ptr = save_ptr;
        c = '\\';
        goto NORMAL_CHAR;
        }
      }
    length++;

    /* A back reference needs an additional char, plus either one or 5
    bytes for a repeat. */

    if (c <= -ESC_REF)
      {
      length++;   /* For single back reference */
      if (ptr[1] == '{')
        {
        ptr = read_repeat_counts(ptr+2, &min, &max, errorptr);
        if (*errorptr != NULL) goto PCRE_ERROR_RETURN;
        if ((min == 0 && (max == 1 || max == -1)) ||
          (min == 1 && max == -1))
            length++;
        else length += 5;
        if (ptr[1] == '?') ptr++;
        }
      }
    continue;

    case '^':
    case '.':
    case '$':
    case '*':     /* These repeats won't be after brackets; */
    case '+':     /* those are handled separately */
    case '?':
    length++;
    continue;

    /* This covers the cases of repeats after a single char, metachar, class,
    or back reference. */

    case '{':
    ptr = read_repeat_counts(ptr+1, &min, &max, errorptr);
    if (*errorptr != NULL) goto PCRE_ERROR_RETURN;
    if ((min == 0 && (max == 1 || max == -1)) ||
      (min == 1 && max == -1))
        length++;
    else
      {
      length--;   /* Uncount the original char or metachar */
      if (min == 1) length++; else if (min > 0) length += 4;
      if (max > 0) length += 4; else length += 2;
      }
    if (ptr[1] == '?') ptr++;
    continue;

    /* An alternation contains an offset to the next branch or ket. */
    case '|':
    length += 3;
    continue;

    /* A character class uses 4 characters plus the characters in it. Don't
    worry about character types that aren't allowed in classes - they'll get
    picked up during the compile. */

    case '[':
    length += 4;
    if (ptr[1] == '^') ptr++;
    do
      {
      if (*(++ptr) == '\\')
        {
        (void)check_escape(&ptr, errorptr);
        if (*errorptr != NULL) goto PCRE_ERROR_RETURN;
        }
      length++;
      }
    while (*ptr != 0 && *ptr != ']');

    /* A repeat needs either 1 or 5 bytes. */

    if (ptr[1] == '{')
      {
      ptr = read_repeat_counts(ptr+2, &min, &max, errorptr);
      if (*errorptr != NULL) goto PCRE_ERROR_RETURN;
      if ((min == 0 && (max == 1 || max == -1)) ||
        (min == 1 && max == -1))
          length++;
      else length += 5;
      if (ptr[1] == '?') ptr++;
      }
    continue;

    /* Brackets may be genuine groups or special things */

    case '(':

    /* Handle special forms of bracket, which all start (? */

    if (ptr[1] == '?') switch (c = ptr[2])
      {
      /* Skip over comments entirely */
      case '#':
      ptr += 3;
      while (*ptr != 0 && *ptr != ')') ptr++;
      if (*ptr == 0)
        {
        *errorptr = "missing ) after comment";
        goto PCRE_ERROR_RETURN;
        }
      continue;

      /* Non-referencing groups and lookaheads just move the pointer on, and
      then behave like a non-special bracket. */

      case ':':
      case '=':
      case '!':
      ptr += 2;
      break;

      /* Else loop setting valid options until ) is met. Anything else is an
      error. */

      case ('P'):
	{
	  int idlen;
	  switch (*ptr++) {
	  case ('<'): 
	    idlen = get_group_id(ptr++, '>', errorptr);
	    if (*errorptr) goto PCRE_ERROR_RETURN;
	    ptr += idlen+1;
	    break;
	  case ('='): 
	    idlen = get_group_id(ptr++, ')', errorptr);
	    if (*errorptr) goto PCRE_ERROR_RETURN;
	    ptr += idlen+1;
	    length++;
	    break;
	  }
	}
	break;

      default:
      ptr += 2;
      for (;; ptr++)
        {
        if ((c = *ptr) == 'i')
          {
          options |= PCRE_CASELESS;
          continue;
          }
        else if ((c = *ptr) == 'm')
          {
          options |= PCRE_MULTILINE;
          continue;
          }
        else if ((c = *ptr) == 's')
          {
          options |= PCRE_DOTALL;
          continue;
          }
        else if (c == 'x')
          {
          options |= PCRE_EXTENDED;
          extended = TRUE;
          length -= spaces;          /* Already counted spaces */
          continue;
          }
        else if (c == ')') break;

        *errorptr = "undefined after (?";
        goto PCRE_ERROR_RETURN;
        }
      continue;                      /* End of this bracket handling */
      }

    /* Non-special forms of bracket. Save length for computing whole length
    at end if there's a repeat that requires duplication of the group. */

    if (brastackptr >= sizeof(brastack)/sizeof(int))
      {
      *errorptr = "too many brackets";
      goto PCRE_ERROR_RETURN;
      }

    brastack[brastackptr++] = length;
    length += 3;
    continue;

    /* Handle ket. Look for subsequent max/min; for certain sets of values we
    have to replicate this bracket up to that many times. */

    case ')':
    length += 3;
      {
      int min = 1;
      int max = 1;
      int duplength = length - brastack[--brastackptr];

      /* Leave ptr at the final char; for read_repeat_counts this happens
      automatically; for the others we need an increment. */

      if ((c = ptr[1]) == '{')
        {
        ptr = read_repeat_counts(ptr+2, &min, &max, errorptr);
        if (*errorptr != NULL) goto PCRE_ERROR_RETURN;
        }
      else if (c == '*') { min = 0; max = -1; ptr++; }
      else if (c == '+') { max = -1; ptr++; }
      else if (c == '?') { min = 0; ptr++; }

      /* If there is a minimum > 1 we have to replicate up to min-1 times; if
      there is a limited maximum we have to replicate up to max-1 times and
      allow for a BRAZERO item before each optional copy, as we also have to
      do before the first copy if the minimum is zero. */

      if (min == 0) length++;
        else if (min > 1) length += (min - 1) * duplength;
      if (max > min) length += (max - min) * (duplength + 1);
      }

    continue;

    /* Non-special character. For a run of such characters the length required
    is the number of characters + 2, except that the maximum run length is 255.
    We won't get a skipped space or a non-data escape or the start of a #
    comment as the first character, so the length can't be zero. */

    NORMAL_CHAR:
    default:
    length += 2;
    runlength = 0;
    do
      {
      if ((pcre_ctypes[c] & ctype_space) != 0)
        {
        if (extended) continue;
        spaces++;
        }

      if (extended && c == '#')
        {
        while ((c = *(++ptr)) != 0 && c != '\n');
        continue;
        }

      /* Backslash may introduce a data char or a metacharacter; stop the
      string before the latter. */

      if (c == '\\')
        {
        uschar *saveptr = ptr;
        c = check_escape(&ptr, errorptr);
        if (*errorptr != NULL) goto PCRE_ERROR_RETURN;
        if (c < 0) { ptr = saveptr; break; }
        }

      /* Ordinary character or single-char escape */

      runlength++;
      }

    /* This "while" is the end of the "do" above. */

    while (runlength < 255 && (pcre_ctypes[c = *(++ptr)] & ctype_meta) == 0);

    ptr--;
    length += runlength;
    continue;
    }
  }

length += 4;    /* For final KET and END */

if (length > 65539)
  {
  *errorptr = "regular expression too large";
  return NULL;
  }

/* Compute the size of data block needed and get it, either from malloc or
externally provided function. Put in the magic number and the options. */

size = length + sizeof(real_pcre) - sizeof(re->code);
re = (real_pcre *)(pcre_malloc)(size);

if (re == NULL)
  {
  *errorptr = "failed to get memory";
  return NULL;
  }

re->magic_number = MAGIC_NUMBER;
re->options = options;

/* Set up a starting, non-extracting bracket, then compile the expression. On
error, *errorptr will be set non-NULL, so we don't need to look at the result
of the function here. */

ptr = (uschar *)pattern;
code = re->code;
*code = OP_BRA;
(void)compile_regexp(extended, brackets, &code, &ptr, errorptr, dictionary);
re->top_bracket = brackets[1];

/* If not reached end of pattern on success, there's an excess bracket. */

if (*errorptr == NULL && *ptr != 0) *errorptr = "unmatched brackets";
/* Fill in the terminating state and check for disastrous overflow, but
if debugging, leave the test till after things are printed out. */

*code++ = OP_END;

#ifndef DEBUG
if (code - re->code > length) *errorptr = "internal error: code overflow";
#endif

/* Failed to compile */

if (*errorptr != NULL)
  {
  (pcre_free)(re);
  PCRE_ERROR_RETURN:
  *erroroffset = ptr - (uschar *)pattern;
  return NULL;
  }

/* If the anchored option was not passed, set flag if we can determine that it
is anchored by virtue of ^ characters or \A or anything else. Otherwise, see if
we can determine what the first character has to be, because that speeds up
unanchored matches no end. In the case of multiline matches, an alternative is
to set the PCRE_STARTLINE flag if all branches start with ^. */

if ((options & PCRE_ANCHORED) == 0)
  {
  if (is_anchored(re->code, (options & PCRE_MULTILINE) != 0))
    re->options |= PCRE_ANCHORED;
  else
    {
    int c = find_firstchar(re->code);
    if (c >= 0)
      {
      re->first_char = c;
      re->options |= PCRE_FIRSTSET;
      }
    else if (is_startline(re->code))
      re->options |= PCRE_STARTLINE;
    }
  }

/* Print out the compiled data for debugging */

#ifdef DEBUG

printf("Length = %d top_bracket = %d%s%s%s%s\n",
  length, re->top_bracket,
  ((re->options & PCRE_ANCHORED) != 0)? " anchored" : "",
  ((re->options & PCRE_CASELESS) != 0)? " caseless" : "",
  extended? " extended" : "",
  ((re->options & PCRE_MULTILINE) != 0)? " multiline" : "");

if ((re->options & PCRE_FIRSTSET) != 0)
  {
  if (isprint(re->first_char)) printf("First char = %c\n", re->first_char);
    else printf("First char = \\x%02x\n", re->first_char);
  }

code_end = code;
code_base = code = re->code;

while (code < code_end)
  {
  int charlength;

  printf("%3d ", code - code_base);

  if (*code >= OP_BRA)
    {
    printf("%3d Bra %d", (code[1] << 8) + code[2], *code - OP_BRA);
    code += 2;
    }

  else switch(*code)
    {
    case OP_CHARS:
    charlength = *(++code);
    printf("%3d ", charlength);
    while (charlength-- > 0)
      if (isprint(c = *(++code))) printf("%c", c); else printf("\\x%02x", c);
    break;

    case OP_KETRMAX:
    case OP_KETRMIN:
    case OP_ALT:
    case OP_KET:
    case OP_ASSERT:
    case OP_ASSERT_NOT:
    printf("%3d %s", (code[1] << 8) + code[2], OP_names[*code]);
    code += 2;
    break;

    case OP_STAR:
    case OP_MINSTAR:
    case OP_PLUS:
    case OP_MINPLUS:
    case OP_QUERY:
    case OP_MINQUERY:
    case OP_TYPESTAR:
    case OP_TYPEMINSTAR:
    case OP_TYPEPLUS:
    case OP_TYPEMINPLUS:
    case OP_TYPEQUERY:
    case OP_TYPEMINQUERY:
    if (*code >= OP_TYPESTAR)
      printf("    %s", OP_names[code[1]]);
    else if (isprint(c = code[1])) printf("    %c", c);
      else printf("    \\x%02x", c);
    printf("%s", OP_names[*code++]);
    break;

    case OP_EXACT:
    case OP_UPTO:
    case OP_MINUPTO:
    if (isprint(c = code[3])) printf("    %c{", c);
      else printf("    \\x%02x{", c);
    if (*code != OP_EXACT) printf(",");
    printf("%d}", (code[1] << 8) + code[2]);
    if (*code == OP_MINUPTO) printf("?");
    code += 3;
    break;

    case OP_TYPEEXACT:
    case OP_TYPEUPTO:
    case OP_TYPEMINUPTO:
    printf("    %s{", OP_names[code[3]]);
    if (*code != OP_TYPEEXACT) printf(",");
    printf("%d}", (code[1] << 8) + code[2]);
    if (*code == OP_TYPEMINUPTO) printf("?");
    code += 3;
    break;

    case OP_REF:
    printf("    \\%d", *(++code));
    break;

    case OP_CLASS:
    case OP_NEGCLASS:
      {
      int i, min, max;
      int flags = code[1];
      int rangecount = code[2];
      int charcount = code[3];

      printf("    [%s", (*code == OP_CLASS)? "" : "^");
      code += 3;

      for (i = 0; i < 8; i++)
        if ((flags & (1 << i)) != 0) printf("%s", class_names[i]);

      for (i = 0; i < rangecount; i++)
        {
        if (isprint(*(++code))) printf("%c-", *code); else printf("\\x%02x-", *code);
        if (isprint(*(++code))) printf("%c", *code); else printf("\\x%02x", *code);
        }

      for (i = 0; i < charcount; i++)
        {
        if (!isprint(*(++code))) printf("\\x%02x", *code);
        else if (strchr("-\\]", *code) != NULL) printf("\\%c", *code);
        else printf("%c", *code);
        }
      printf("]");

      switch(*(++code))
        {
        case OP_CRSTAR:
        case OP_CRMINSTAR:
        case OP_CRPLUS:
        case OP_CRMINPLUS:
        case OP_CRQUERY:
        case OP_CRMINQUERY:
        printf("%s", OP_names[*code]);
        break;

        case OP_CRRANGE:
        case OP_CRMINRANGE:
        min = (code[1] << 8) + code[2];
        max = (code[3] << 8) + code[4];
        if (max == 0) printf("{%d,}", min);
        else printf("{%d,%d}", min, max);
        if (*code == OP_CRMINRANGE) printf("?");
        code += 4;
        break;

        default:
        code--;
        }
      }
    break;

    /* Anything else is just a one-node item */

    default:
    printf("    %s", OP_names[*code]);
    break;
    }

  code++;
  printf("\n");
  }
printf("------------------------------------------------------------------\n");

/* This check is done here in the debugging case so that the code that
was compiled can be seen. */

if (code - re->code > length)
  {
  *errorptr = "internal error: code overflow";
  (pcre_free)(re);
  *erroroffset = ptr - (uschar *)pattern;
  return NULL;
  }
#endif

return (pcre *)re;
}



/*************************************************
*        Match a character type                  *
*************************************************/

/* Not used in all the places it might be as it's sometimes faster
to put the code inline.

Arguments:
  type        the character type
  c           the character
  multiline   the multiline flag

Returns:      TRUE if character is of the type
*/

static BOOL
match_type(int type, int c, BOOL dotall)
{

#ifdef DEBUG
if (isprint(c)) printf("matching subject %c against ", c);
  else printf("matching subject \\x%02x against ", c);
printf("%s\n", OP_names[type]);
#endif

switch(type)
  {
  case OP_ANY:            return dotall || c != '\n';
  case OP_NOT_DIGIT:      return (pcre_ctypes[c] & ctype_digit) == 0;
  case OP_DIGIT:          return (pcre_ctypes[c] & ctype_digit) != 0;
  case OP_NOT_WHITESPACE: return (pcre_ctypes[c] & ctype_space) == 0;
  case OP_WHITESPACE:     return (pcre_ctypes[c] & ctype_space) != 0;
  case OP_NOT_WORDCHAR:   return (pcre_ctypes[c] & ctype_word) == 0;
  case OP_WORDCHAR:       return (pcre_ctypes[c] & ctype_word) != 0;
  }
return FALSE;
}


/*************************************************
*            Match a character class             *
*************************************************/

/* Return "result" if char is in the class and "!result" otherwise.

Arguments:
  data        points to the class item
  c           the subject character
  result      value to return if in class
  md          matching "static" data

Returns:      result or !result
*/

static BOOL
match_class(register uschar *data, register int c, BOOL result, match_data *md)
{
int flags = data[1];
int i;
uschar *base = data;
uschar *end;

#ifdef DEBUG
  {
  uschar *d = base + 3;

  if (isprint(c))
    printf("match %c against [%s", c, result? "" : "^");
  else
    printf("match \\x%02x against [%s", c, result? "" : "^");

  for (i = 0; i < 8; i++)
    if ((flags & (1 << i)) != 0) printf("%s", class_names[i]);

  for (i = 0; i < data[2]; i++)
    {
    if (isprint(*(++d))) printf("%c-", *d); else printf("\\x%02x-", *d);
    if (isprint(*(++d))) printf("%c", *d); else printf("\\x%02x", *d);
    }

  for (i = 0; i < data[3]; i++)
    {
    if (!isprint(*(++d))) printf("\\x%02x", *d);
    else if (strchr("-\\]", *d) != NULL) printf("\\%c", *d);
    else printf("%c", *d);
    }
  printf("]\n");
  }
#endif

/* Test for any character types */

for (i = 0; flags != 0; i++)
  {
  if ((flags & 1) != 0 && match_type(class_ops[i], c, md->dotall))
    return result;
  flags >>= 1;
  }

/* Advance pointer to the specific chars and do the caseless or caseful testing
of the ranges and individual characters as necessary. */

data += 4;
end = data + base[2] * 2;

/* Caseless character ranges are slightly tricky, because of cases like [W-c].
What we do is to uppercase the subject char if it is beyond the end of the
range, or lowercase it if it is before the start of the range and try again if
a caseful comparison has failed. This works because upper case letters come
before lower case in ASCII code. It would not work in EBCDIC, for example,
where they are the other way round, but then ranges like [W-c] would be illegal
in EBCDIC. */

if (md->caseless)
  {
  while (data < end)
    {
    register int d;
    if (c >= (int)*data && c <= (int)data[1]) return result;
    d = (c < (int)*data)? pcre_lcc[c] : pcre_ucc[c];
    if (d >= (int)*data && d <= (int)data[1]) return result;
    data += 2;
    }
  end += base[3];
  c = pcre_lcc[c];
  while (data < end) if (c == pcre_lcc[*data++]) return result;
  }

/* Caseful is easy */

else
  {
  while (data < end)
    {
    if (c >= (int)*data && c <= (int)data[1]) return result;
    data += 2;
    }
  end += base[3];
  while (data < end) if (c == *data++) return result;
  }

/* Character is not in the class */

return !result;
}



/*************************************************
*          Match a back-reference                *
*************************************************/

/* If a back reference hasn't been set, the match fails.

Arguments:
  number      reference number
  eptr        points into the subject
  length      length to be matched
  md          points to match data block

Returns:      TRUE if matched
*/

static BOOL
match_ref(int number, register uschar *eptr, int length, match_data *md)
{
uschar *p = md->start_subject + md->offset_vector[number];

#ifdef DEBUG
if (eptr >= md->end_subject)
  printf("matching subject <null>");
else
  {
  printf("matching subject ");
  pchars(eptr, length, TRUE, md);
  }
printf(" against backref ");
pchars(p, length, FALSE, md);
printf("\n");
#endif

/* Always fail if not enough characters left */

if (length > md->end_subject - p) return FALSE;

/* Separate the caselesss case for speed */

if (md->caseless)
  { while (length-- > 0) if (pcre_lcc[*p++] != pcre_lcc[*eptr++]) return FALSE; }
else
  { while (length-- > 0) if (*p++ != *eptr++) return FALSE; }

return TRUE;
}

static int free_stack(match_data *md)
{
/* Free any stack space that was allocated by the call to match(). */
if (md->off_num)    free(md->off_num); 
if (md->offset_top) free(md->offset_top); 
if (md->r1)         free(md->r1); 
if (md->r2)         free(md->r2); 
if (md->eptr)       free(md->eptr); 
if (md->ecode)      free(md->ecode);
return 0;
}

static int grow_stack(match_data *md)
{
  md->length = md->length ? md->length+md->length/2 : 200; 
  md->offset_top=realloc(md->offset_top, md->length*sizeof(int)); 
  md->eptr=realloc(md->eptr, md->length*sizeof(void *)); 
  md->ecode=realloc(md->ecode, md->length*sizeof(void *)); 
  md->off_num=realloc(md->off_num, md->length*sizeof(int)); 
  md->r1=realloc(md->r1, md->length*sizeof(int)); 
  md->r2=realloc(md->r2, md->length*sizeof(int));
  return 0;
}

/*************************************************
*         Match from current position            *
*************************************************/

/* On entry ecode points to the first opcode, and eptr to the first character.

Arguments:
   eptr        pointer in subject
   ecode       position in code
   offset_top  current top pointer
   md          pointer to "static" info for the match

Returns:       TRUE if matched
*/

static BOOL
match(register uschar *eptr, register uschar *ecode, int offset_top,
  match_data *md)
{
  int save_stack_position = md->point;
match_loop:

#define SUCCEED goto succeed
#define FAIL    goto fail

for (;;)
  {
  int min, max, ctype;
  register int i;
  register int c;
  BOOL minimize = 0;

  /* Opening bracket. Check the alternative branches in turn, failing if none
  match. We have to set the start offset if required and there is space
  in the offset vector so that it is available for subsequent back references
  if the bracket matches. However, if the bracket fails, we must put back the
  previous value of both offsets in case they were set by a previous copy of
  the same bracket. Don't worry about setting the flag for the error case here;
  that is handled in the code for KET. */

  if ((int)*ecode >= OP_BRA)
    {
    int number = (*ecode - OP_BRA) << 1;
    int save_offset1 = 0, save_offset2 = 0;

    #ifdef DEBUG
    printf("start bracket %d\n", number/2);
    #endif

    if (number > 0 && number < md->offset_end)
      {
      save_offset1 = md->offset_vector[number];
      save_offset2 = md->offset_vector[number+1];
      md->offset_vector[number] = eptr - md->start_subject;

      #ifdef DEBUG
      printf("saving %d %d\n", save_offset1, save_offset2);
      #endif
      }

    /* Recurse for all the alternatives. */

    do
      {
      if (match(eptr, ecode+3, offset_top, md)) SUCCEED;
      ecode += (ecode[1] << 8) + ecode[2];
      }
    while (*ecode == OP_ALT);

    #ifdef DEBUG
    printf("bracket %d failed\n", number/2);
    #endif

    if (number > 0 && number < md->offset_end)
      {
      md->offset_vector[number] = save_offset1;
      md->offset_vector[number+1] = save_offset2;
      }

    FAIL;
    }

  /* Other types of node can be handled by a switch */

  switch(*ecode)
    {
    case OP_END:
    md->end_match_ptr = eptr;          /* Record where we ended */
    md->end_offset_top = offset_top;   /* and how many extracts were taken */
    SUCCEED;

    /* Assertion brackets. Check the alternative branches in turn - the
    matching won't pass the KET for an assertion. If any one branch matches,
    the assertion is true. */

    case OP_ASSERT:
    do
      {
      if (match(eptr, ecode+3, offset_top, md)) break;
      ecode += (ecode[1] << 8) + ecode[2];
      }
    while (*ecode == OP_ALT);
    if (*ecode == OP_KET) FAIL;

    /* Continue from after the assertion, updating the offsets high water
    mark, since extracts may have been taken during the assertion. */

    do ecode += (ecode[1] << 8) + ecode[2]; while (*ecode == OP_ALT);
    ecode += 3;
    offset_top = md->end_offset_top;
    continue;

    /* Negative assertion: all branches must fail to match */

    case OP_ASSERT_NOT:
    do
      {
      if (match(eptr, ecode+3, offset_top, md)) FAIL;
      ecode += (ecode[1] << 8) + ecode[2];
      }
    while (*ecode == OP_ALT);
    ecode += 3;
    continue;

    /* An alternation is the end of a branch; scan along to find the end of the
    bracketed group and go to there. */

    case OP_ALT:
    do ecode += (ecode[1] << 8) + ecode[2]; while (*ecode == OP_ALT);
    break;

    /* BRAZERO and BRAMINZERO occur just before a bracket group, indicating
    that it may occur zero times. It may repeat infinitely, or not at all -
    i.e. it could be ()* or ()? in the pattern. Brackets with fixed upper
    repeat limits are compiled as a number of copies, with the optional ones
    preceded by BRAZERO or BRAMINZERO. */

    case OP_BRAZERO:
      {
      uschar *next = ecode+1;
      if (match(eptr, next, offset_top, md)) SUCCEED;
      do next += (next[1] << 8) + next[2]; while (*next == OP_ALT);
      ecode = next + 3;
      }
    break;

    case OP_BRAMINZERO:
      {
      uschar *next = ecode+1;
      do next += (next[1] << 8) + next[2]; while (*next == OP_ALT);
      if (match(eptr, next+3, offset_top, md)) SUCCEED;
      ecode++;
      }
    break;;

    /* End of a group, repeated or non-repeating. If we are at the end of
    an assertion "group", stop matching and SUCCEED, but record the
    current high water mark for use by positive assertions. */

    case OP_KET:
    case OP_KETRMIN:
    case OP_KETRMAX:
      {
      int number, start, end;
      uschar *prev = ecode - (ecode[1] << 8) - ecode[2];

      if (*prev == OP_ASSERT || *prev == OP_ASSERT_NOT)
        {
        md->end_offset_top = offset_top;
        SUCCEED;
        }

      /* In all other cases we have to check the group number back at the
      start and if necessary complete handling an extraction by setting the
      final offset and bumping the high water mark. */

      number = (*prev - OP_BRA) << 1;

      #ifdef DEBUG
      printf("end bracket %d\n", number/2);
      #endif

      if (number > 0)
        {
        if (number >= md->offset_end) md->offset_overflow = TRUE; else
          {
          start=md->offset_vector[number] ; end =md->offset_vector[number+1];
          md->offset_vector[number+1] = eptr - md->start_subject;
          if (offset_top <= number) offset_top = number + 2;
          }
        }

      /* For a non-repeating ket, just advance to the next node and continue at
      this level. */

      if (*ecode == OP_KET)
        {
        ecode += 3;
        break;
        }

      /* The repeating kets try the rest of the pattern or restart from the
      preceding bracket, in the appropriate order. */

      if (*ecode == OP_KETRMIN)
        {
	uschar *ptr;
	if (match(eptr, ecode+3, offset_top, md)) goto succeed;
	/* Handle alternation inside the BRA...KET; push the additional
	   alternatives onto the stack 
	   XXX this tries the alternatives backwards! */
	ptr=prev;
	do {
	  ptr += (ptr[1]<<8)+ ptr[2];
	  if (*ptr==OP_ALT) 
	    {
	      if (md->length == md->point) grow_stack(md);
	      md->offset_top[md->point] = offset_top; 
	      md->eptr[md->point]       = eptr; 
	      md->ecode[md->point]      = ptr+3; 
	      md->r1[md->point]         = 0; 
	      md->r2[md->point]         = 0; 
	      md->off_num[md->point]    = 0; 
	      md->point++;	      
	    }
	} while (*ptr==OP_ALT);
	ecode=prev+3; goto match_loop;
        }
      else  /* OP_KETRMAX */
        {
	uschar *ptr;
	int points_pushed=0;

	/* Push one failure point, that will resume matching at the code after 
	   the KETRMAX opcode. */
	if (md->length == md->point) grow_stack(md);
	md->offset_top[md->point] = offset_top; 
	md->eptr[md->point]       = eptr; 
	md->ecode[md->point]      = ecode+3; 
	md->r1[md->point]         = md->offset_vector[number]; 
	md->r2[md->point]         = md->offset_vector[number+1]; 
	md->off_num[md->point]    = number; 
	md->point++;	      

	md->offset_vector[number] = eptr - md->start_subject;
	/* Handle alternation inside the BRA...KET; push each of the
	   additional alternatives onto the stack 
	   XXX this tries the alternatives backwards! */
	ptr=prev;
	do {
	  ptr += (ptr[1]<<8)+ ptr[2];
	  if (*ptr==OP_ALT) 
	    {
	      if (md->length == md->point) grow_stack(md);
	      md->offset_top[md->point] = offset_top; 
	      md->eptr[md->point]       = eptr; 
	      md->ecode[md->point]      = ptr+3; 
	      md->r1[md->point]         = 0; 
	      md->r2[md->point]         = 0; 
	      md->off_num[md->point]    = 0; 
	      md->point++;	      
	      points_pushed++;
	    }
	} while (*ptr==OP_ALT);
	/* Jump to the first (or only) alternative and resume trying to match */
	ecode=prev+3; goto match_loop;
        }
      }
    FAIL;

    /* Start of subject, or after internal newline if multiline */

    case OP_CIRC:
    if (md->multiline)
      {
      if (eptr != md->start_subject && eptr[-1] != '\n') FAIL;
      ecode++;
      break;
      }
    /* ... else fall through */

    /* Start of subject assertion */

    case OP_SOD:
    if (eptr != md->start_subject) FAIL;
    ecode++;
    break;

    /* End of subject, or before internal newline if multiline */

    case OP_DOLL:
    if (md->multiline)
      {
      if (eptr < md->end_subject && *eptr != '\n') FAIL;
      ecode++;
      break;
      }
    /* ... else fall through */

    /* End of subject assertion */

    case OP_EOD:
    if (eptr < md->end_subject) FAIL;
    ecode++;
    break;

    /* Word boundary assertions */

    case OP_NOT_WORD_BOUNDARY:
    case OP_WORD_BOUNDARY:
      {
      BOOL prev_is_word = (eptr != md->start_subject) &&
        ((pcre_ctypes[eptr[-1]] & ctype_word) != 0);
      BOOL cur_is_word = (eptr < md->end_subject) &&
        ((pcre_ctypes[*eptr] & ctype_word) != 0);
      if ((*ecode++ == OP_WORD_BOUNDARY)?
           cur_is_word == prev_is_word : cur_is_word != prev_is_word)
        FAIL;
      }
    break;

    /* Match a single character type; inline for speed */

    case OP_ANY:
    if (!md->dotall && eptr < md->end_subject && *eptr == '\n') FAIL;
    if (eptr++ >= md->end_subject) FAIL;
    ecode++;
    break;

    case OP_NOT_DIGIT:
    if (eptr >= md->end_subject || (pcre_ctypes[*eptr++] & ctype_digit) != 0)
      FAIL;
    ecode++;
    break;

    case OP_DIGIT:
    if (eptr >= md->end_subject || (pcre_ctypes[*eptr++] & ctype_digit) == 0)
      FAIL;
    ecode++;
    break;

    case OP_NOT_WHITESPACE:
    if (eptr >= md->end_subject || (pcre_ctypes[*eptr++] & ctype_space) != 0)
      FAIL;
    ecode++;
    break;

    case OP_WHITESPACE:
    if (eptr >= md->end_subject || (pcre_ctypes[*eptr++] & ctype_space) == 0)
      FAIL;
    ecode++;
    break;

    case OP_NOT_WORDCHAR:
    if (eptr >= md->end_subject || (pcre_ctypes[*eptr++] & ctype_word) != 0)
      FAIL;
    ecode++;
    break;

    case OP_WORDCHAR:
    if (eptr >= md->end_subject || (pcre_ctypes[*eptr++] & ctype_word) == 0)
      FAIL;
    ecode++;
    break;

    /* Match a back reference, possibly repeatedly. Look past the end of the
    item to see if there is repeat information following. The code is similar
    to that for character classes, but repeated for efficiency. Then obey
    similar code to character type repeats - written out again for speed.
    However, if the referenced string is the empty string, always treat
    it as matched, any number of times (otherwise there could be infinite
    loops). */

    case OP_REF:
      {
      int length;
      int number = ecode[1] << 1;                /* Doubled reference number */
      ecode += 2;                                /* Advance past the item */

      if (number >= offset_top || md->offset_vector[number] < 0)
        {
        md->errorcode = PCRE_ERROR_BADREF;
        FAIL;
        }

      length = md->offset_vector[number+1] - md->offset_vector[number];

      switch (*ecode)
        {
        case OP_CRSTAR:
        case OP_CRMINSTAR:
        case OP_CRPLUS:
        case OP_CRMINPLUS:
        case OP_CRQUERY:
        case OP_CRMINQUERY:
        c = *ecode++ - OP_CRSTAR;
        minimize = (c & 1) != 0;
        min = rep_min[c];                 /* Pick up values from tables; */
        max = rep_max[c];                 /* zero for max => infinity */
        if (max == 0) max = INT_MAX;
        break;

        case OP_CRRANGE:
        case OP_CRMINRANGE:
        minimize = (*ecode == OP_CRMINRANGE);
        min = (ecode[1] << 8) + ecode[2];
        max = (ecode[3] << 8) + ecode[4];
        if (max == 0) max = INT_MAX;
        ecode += 5;
        break;

        default:               /* No repeat follows */
        if (!match_ref(number, eptr, length, md)) FAIL;
        eptr += length;
        continue;              /* With the main loop */
        }

      /* If the length of the reference is zero, just continue with the
      main loop. */

      if (length == 0) continue;

      /* First, ensure the minimum number of matches are present. We get back
      the length of the reference string explicitly rather than passing the
      address of eptr, so that eptr can be a register variable. */

      for (i = 1; i <= min; i++)
        {
        if (!match_ref(number, eptr, length, md)) FAIL;
        eptr += length;
        }

      /* If min = max, continue at the same level without recursion.
      They are not both allowed to be zero. */

      if (min == max) continue;

      /* If minimizing, keep trying and advancing the pointer */

      if (minimize)
        {
        for (i = min;; i++)
          {
          if (match(eptr, ecode, offset_top, md)) SUCCEED;
          if (i >= max || !match_ref(number, eptr, length, md))
            FAIL;
          eptr += length;
          }
        /* Control never gets here */
        }

      /* If maximizing, find the longest string and work backwards */

      else
        {
        uschar *pp = eptr;
        for (i = min; i < max; i++)
          {
          if (!match_ref(number, eptr, length, md)) break;
          eptr += length;
          }
        while (eptr >= pp)
          {
          if (match(eptr, ecode, offset_top, md)) SUCCEED;
          eptr -= length;
          }
        FAIL;
        }
      }
    /* Control never gets here */

    /* Match a character class, possibly repeatedly. Look past the end of the
    item to see if there is repeat information following. Then obey similar
    code to character type repeats - written out again for speed. */

    case OP_CLASS:
    case OP_NEGCLASS:
      {
      BOOL result = *ecode == OP_CLASS;
      uschar *data = ecode;               /* Save for matching */

      ecode += 4 + 2 * ecode[2] + ecode[3];      /* Advance past the item */

      switch (*ecode)
        {
        case OP_CRSTAR:
        case OP_CRMINSTAR:
        case OP_CRPLUS:
        case OP_CRMINPLUS:
        case OP_CRQUERY:
        case OP_CRMINQUERY:
        c = *ecode++ - OP_CRSTAR;
        minimize = (c & 1) != 0;
        min = rep_min[c];                 /* Pick up values from tables; */
        max = rep_max[c];                 /* zero for max => infinity */
        if (max == 0) max = INT_MAX;
        break;

        case OP_CRRANGE:
        case OP_CRMINRANGE:
        minimize = (*ecode == OP_CRMINRANGE);
        min = (ecode[1] << 8) + ecode[2];
        max = (ecode[3] << 8) + ecode[4];
        if (max == 0) max = INT_MAX;
        ecode += 5;
        break;

        default:               /* No repeat follows */
        if (eptr >= md->end_subject || !match_class(data, *eptr++, result, md))
          FAIL;
        continue;              /* With the main loop */
        }

      /* First, ensure the minimum number of matches are present. */

      for (i = 1; i <= min; i++)
        if (eptr >= md->end_subject || !match_class(data, *eptr++, result, md))
          FAIL;

      /* If max == min we can continue with the main loop without the
      need to recurse. */

      if (min == max) continue;

      /* If minimizing, keep testing the rest of the expression and advancing
      the pointer while it matches the class. */

      if (minimize)
        {
        for (i = min;; i++)
          {
          if (match(eptr, ecode, offset_top, md)) SUCCEED;
          if (i >= max || eptr >= md->end_subject ||
            !match_class(data, *eptr++, result, md)) FAIL;
          }
        /* Control never gets here */
        }

      /* If maximizing, find the longest possible run, then work backwards. */

      else
        {
        uschar *pp = eptr;
        for (i = min; i < max; i++)
          {
          if (eptr >= md->end_subject || !match_class(data, *eptr, result, md))
            break;
          eptr++;
          }
        while (eptr >= pp)
          if (match(eptr--, ecode, offset_top, md)) SUCCEED;
        FAIL;
        }
      }
    /* Control never gets here */

    /* Match a run of characters */

    case OP_CHARS:
      {
      register int length = ecode[1];
      ecode += 2;

      #ifdef DEBUG
      if (eptr >= md->end_subject)
        printf("matching subject <null> against pattern ");
      else
        {
        printf("matching subject ");
        pchars(eptr, length, TRUE, md);
        printf(" against pattern ");
        }
      pchars(ecode, length, FALSE, md);
      printf("\n");
      #endif

      if (length > md->end_subject - eptr) FAIL;
      if (md->caseless)
        {
        while (length-- > 0) if (pcre_lcc[*ecode++] != pcre_lcc[*eptr++]) FAIL;
        }
      else
        {
        while (length-- > 0) if (*ecode++ != *eptr++) FAIL;
        }
      }
    break;

    /* Match a single character repeatedly; different opcodes share code. */

    case OP_EXACT:
    min = max = (ecode[1] << 8) + ecode[2];
    ecode += 3;
    goto REPEATCHAR;

    case OP_UPTO:
    case OP_MINUPTO:
    min = 0;
    max = (ecode[1] << 8) + ecode[2];
    minimize = *ecode == OP_MINUPTO;
    ecode += 3;
    goto REPEATCHAR;

    case OP_STAR:
    case OP_MINSTAR:
    case OP_PLUS:
    case OP_MINPLUS:
    case OP_QUERY:
    case OP_MINQUERY:
    c = *ecode++ - OP_STAR;
    minimize = (c & 1) != 0;
    min = rep_min[c];                 /* Pick up values from tables; */
    max = rep_max[c];                 /* zero for max => infinity */
    if (max == 0) max = INT_MAX;

    /* Common code for all repeated single-character matches. We can give
    up quickly if there are fewer than the minimum number of characters left in
    the subject. */

    REPEATCHAR:
    if (min > md->end_subject - eptr) FAIL;
    c = *ecode++;

    /* The code is duplicated for the caseless and caseful cases, for speed,
    since matching characters is likely to be quite common. First, ensure the
    minimum number of matches are present. If min = max, continue at the same
    level without recursing. Otherwise, if minimizing, keep trying the rest of
    the expression and advancing one matching character if failing, up to the
    maximum. Alternatively, if maximizing, find the maximum number of
    characters and work backwards. */

    #ifdef DEBUG
    printf("matching %c{%d,%d} against subject %.*s\n", c, min, max,
      max, eptr);
    #endif

    if (md->caseless)
      {
      c = pcre_lcc[c];
      for (i = 1; i <= min; i++) if (c != pcre_lcc[*eptr++]) FAIL;
      if (min == max) continue;
      if (minimize)
        {
        for (i = min;; i++)
          {
          if (match(eptr, ecode, offset_top, md)) SUCCEED;
          if (i >= max || eptr >= md->end_subject || c != pcre_lcc[*eptr++])
            FAIL;
          }
        /* Control never gets here */
        }
      else
        {
        uschar *pp = eptr;
        for (i = min; i < max; i++)
          {
          if (eptr >= md->end_subject || c != pcre_lcc[*eptr]) break;
          eptr++;
          }
        while (eptr >= pp)
          if (match(eptr--, ecode, offset_top, md)) SUCCEED;
        FAIL;
        }
      }

    /* Caseful comparisons */

    else
      {
      for (i = 1; i <= min; i++) if (c != *eptr++) FAIL;
      if (min == max) continue;
      if (minimize)
        {
        for (i = min;; i++)
          {
          if (match(eptr, ecode, offset_top, md)) SUCCEED;
          if (i >= max || eptr >= md->end_subject || c != *eptr++) FAIL;
          }
        /* Control never gets here */
        }
      else
        {
        uschar *pp = eptr;
        for (i = min; i < max; i++)
          {
          if (eptr >= md->end_subject || c != *eptr) break;
          eptr++;
          }
        while (eptr >= pp)
         if (match(eptr--, ecode, offset_top, md)) SUCCEED;
        FAIL;
        }
      }
    /* Control never gets here */

    /* Match a single character type repeatedly; several different opcodes
    share code. This is very similar to the code for single characters, but we
    repeat it in the interests of efficiency. */

    case OP_TYPEEXACT:
    min = max = (ecode[1] << 8) + ecode[2];
    minimize = TRUE;
    ecode += 3;
    goto REPEATTYPE;

    case OP_TYPEUPTO:
    case OP_TYPEMINUPTO:
    min = 0;
    max = (ecode[1] << 8) + ecode[2];
    minimize = *ecode == OP_TYPEMINUPTO;
    ecode += 3;
    goto REPEATTYPE;

    case OP_TYPESTAR:
    case OP_TYPEMINSTAR:
    case OP_TYPEPLUS:
    case OP_TYPEMINPLUS:
    case OP_TYPEQUERY:
    case OP_TYPEMINQUERY:
    c = *ecode++ - OP_TYPESTAR;
    minimize = (c & 1) != 0;
    min = rep_min[c];                 /* Pick up values from tables; */
    max = rep_max[c];                 /* zero for max => infinity */
    if (max == 0) max = INT_MAX;

    /* Common code for all repeated single character type matches */

    REPEATTYPE:
    ctype = *ecode++;      /* Code for the character type */

    /* First, ensure the minimum number of matches are present. Use inline
    code for maximizing the speed, and do the type test once at the start
    (i.e. keep it out of the loop). Also test that there are at least the
    minimum number of characters before we start. */

    if (min > md->end_subject - eptr) FAIL;
    if (min > 0) switch(ctype)
      {
      case OP_ANY:
      if (!md->dotall)
        { for (i = 1; i <= min; i++) if (*eptr++ == '\n') FAIL; }
      else eptr += min;
      break;

      case OP_NOT_DIGIT:
      for (i = 1; i <= min; i++)
        if ((pcre_ctypes[*eptr++] & ctype_digit) != 0) FAIL;
      break;

      case OP_DIGIT:
      for (i = 1; i <= min; i++)
        if ((pcre_ctypes[*eptr++] & ctype_digit) == 0) FAIL;
      break;

      case OP_NOT_WHITESPACE:
      for (i = 1; i <= min; i++)
        if ((pcre_ctypes[*eptr++] & ctype_space) != 0) FAIL;
      break;

      case OP_WHITESPACE:
      for (i = 1; i <= min; i++)
        if ((pcre_ctypes[*eptr++] & ctype_space) == 0) FAIL;
      break;

      case OP_NOT_WORDCHAR:
      for (i = 1; i <= min; i++) if ((pcre_ctypes[*eptr++] & ctype_word) != 0)
        FAIL;
      break;

      case OP_WORDCHAR:
      for (i = 1; i <= min; i++) if ((pcre_ctypes[*eptr++] & ctype_word) == 0)
        FAIL;
      break;
      }

    /* If min = max, continue at the same level without recursing */

    if (min == max) continue;

    /* If minimizing, we have to test the rest of the pattern before each
    subsequent match, so inlining isn't much help; just use the function. */

    if (minimize)
      {
      for (i = min;; i++)
        {
        if (match(eptr, ecode, offset_top, md)) SUCCEED;
        if (i >= max || eptr >= md->end_subject ||
          !match_type(ctype, *eptr++, md->dotall))
            FAIL;
        }
      /* Control never gets here */
      }

    /* If maximizing it is worth using inline code for speed, doing the type
    test once at the start (i.e. keep it out of the loop). */

    else
      {
      uschar *pp = eptr;
      switch(ctype)
        {
        case OP_ANY:
        if (!md->dotall)
          {
          for (i = min; i < max; i++)
            {
            if (eptr >= md->end_subject || *eptr == '\n') break;
            eptr++;
            }
          }
        else
          {
          c = max - min;
          if (c > md->end_subject - eptr) c = md->end_subject - eptr;
          eptr += c;
          }
        break;

        case OP_NOT_DIGIT:
        for (i = min; i < max; i++)
          {
          if (eptr >= md->end_subject || (pcre_ctypes[*eptr] & ctype_digit) != 0)
            break;
          eptr++;
          }
        break;

        case OP_DIGIT:
        for (i = min; i < max; i++)
          {
          if (eptr >= md->end_subject || (pcre_ctypes[*eptr] & ctype_digit) == 0)
            break;
          eptr++;
          }
        break;

        case OP_NOT_WHITESPACE:
        for (i = min; i < max; i++)
          {
          if (eptr >= md->end_subject || (pcre_ctypes[*eptr] & ctype_space) != 0)
            break;
          eptr++;
          }
        break;

        case OP_WHITESPACE:
        for (i = min; i < max; i++)
          {
          if (eptr >= md->end_subject || (pcre_ctypes[*eptr] & ctype_space) == 0)
            break;
          eptr++;
          }
        break;

        case OP_NOT_WORDCHAR:
        for (i = min; i < max; i++)
          {
          if (eptr >= md->end_subject || (pcre_ctypes[*eptr] & ctype_word) != 0)
            break;
          eptr++;
          }
        break;

        case OP_WORDCHAR:
        for (i = min; i < max; i++)
          {
          if (eptr >= md->end_subject || (pcre_ctypes[*eptr] & ctype_word) == 0)
            break;
          eptr++;
          }
        break;
        }

      while (eptr >= pp)
        if (match(eptr--, ecode, offset_top, md)) SUCCEED;
      FAIL;
      }
    /* Control never gets here */

    /* There's been some horrible disaster. */

    default:
    #ifdef DEBUG
    printf("Unknown opcode %d\n", *ecode);
    #endif
    md->errorcode = PCRE_ERROR_UNKNOWN_NODE;
    FAIL;
    }

  /* Do not stick any code in here without much thought; it is assumed
  that "continue" in the code above comes out to here to repeat the main
  loop. */

  }             /* End of main loop */
/* Control never reaches here */

fail: 
 if (md->point > save_stack_position)
 {
   /* If there are still points remaining on the stack, pop the next one off */
   int off_num;

   md->point--; 
   offset_top = md->offset_top[md->point]; 
   eptr       = md->eptr[md->point]; 
   ecode      = md->ecode[md->point]; 
   off_num    = md->off_num[md->point];
   md->offset_vector[off_num]   = md->r1[md->point]; 
   md->offset_vector[off_num+1] = md->r2[md->point]; 
   goto match_loop;
  }
   /* Failure, and nothing left on the stack, so end this function call */

 /* Restore the top of the stack to where it was before this function
    call.  This lets us use one stack for everything; recursive calls
    can push and pop information, and may increase the stack.  When
    the call returns, the parent function can resume pushing and
    popping wherever it was. */

 md->point = save_stack_position;
 return FALSE;

succeed:
 return TRUE;
}


/*************************************************
*         Execute a Regular Expression           *
*************************************************/

/* This function applies a compiled re to a subject string and picks out
portions of the string if it matches. Two elements in the vector are set for
each substring: the offsets to the start and end of the substring.

Arguments:
  re           points to the compiled expression
  extra        points to "hints" from pcre_study() or is NULL
  subject      points to the subject string
  length       length of subject string (may contain binary zeros)
  options      option bits
  offsets      points to a vector of ints to be filled in with offsets
  offsetcount  the number of elements in the vector

Returns:       > 0 => success; value is the number of elements filled in
               = 0 => success, but offsets is not big enough
                -1 => failed to match
              < -1 => some kind of unexpected problem
*/

int
pcre_exec(pcre *external_re, pcre_extra *external_extra, char *subject,
  int length, int options, int *offsets, int offsetcount)
{
int resetcount;
int first_char = -1;
match_data match_block;
uschar *start_bits = NULL;
uschar *start_match = (uschar *)subject;
uschar *end_subject;
real_pcre *re = (real_pcre *)external_re;
real_pcre_extra *extra = (real_pcre_extra *)external_extra;
BOOL anchored = ((re->options | options) & PCRE_ANCHORED) != 0;
BOOL startline = (re->options & PCRE_STARTLINE) != 0;

if ((options & ~PUBLIC_EXEC_OPTIONS) != 0) return PCRE_ERROR_BADOPTION;

if (re == NULL || subject == NULL ||
   (offsets == NULL && offsetcount > 0)) return PCRE_ERROR_NULL;
if (re->magic_number != MAGIC_NUMBER) return PCRE_ERROR_BADMAGIC;

match_block.start_subject = (uschar *)subject;
match_block.end_subject = match_block.start_subject + length;
end_subject = match_block.end_subject;

match_block.caseless = ((re->options | options) & PCRE_CASELESS) != 0;
match_block.multiline = ((re->options |options) & PCRE_MULTILINE) != 0;
match_block.dotall   = ((re->options |options) & PCRE_DOTALL) != 0;

match_block.offset_vector = offsets;            /* Where offsets go */
match_block.offset_end = (offsetcount & (-2));  /* Past max permitted (even) */
match_block.offset_overflow = FALSE;

match_block.errorcode = PCRE_ERROR_NOMATCH;     /* Default error */

/* Set the stack state to empty */
  match_block.off_num = match_block.offset_top = NULL;
  match_block.r1 = match_block.r2 = NULL;
  match_block.eptr = match_block.ecode = NULL;
  match_block.point = match_block.length = 0;

/* Compute the minimum number of offsets that we need to reset each time. Doing
this makes a huge difference to execution time when there aren't many brackets
in the pattern. */

resetcount = 2 + re->top_bracket * 2;
if (resetcount > offsetcount) resetcount = offsetcount;

/* If MULTILINE is set at exec time but was not set at compile time, and the
anchored flag is set, we must re-check because a setting provoked by ^ in the
pattern is not right in multi-line mode. Calling is_anchored() again here does
the right check, because multiline is now set. If it now yields FALSE, the
expression must have had ^ starting some of its branches. Check to see if
that is true for *all* branches, and if so, set the startline flag. */

if (match_block. multiline && anchored && (re->options & PCRE_MULTILINE) == 0 &&
    !is_anchored(re->code, match_block.multiline))
  {
  anchored = FALSE;
  if (is_startline(re->code)) startline = TRUE;
  }

/* Set up the first character to match, if available. The first_char value is
never set for an anchored regular expression, but the anchoring may be forced
at run time, so we have to test for anchoring. The first char may be unset for
an unanchored pattern, of course. If there's no first char and the pattern was
studied, the may be a bitmap of possible first characters. However, we can
use this only if the caseless state of the studying was correct. */

if (!anchored)
  {
  if ((re->options & PCRE_FIRSTSET) != 0)
    {
    first_char = re->first_char;
    if (match_block.caseless) first_char = pcre_lcc[first_char];
    }
  else
    if (!startline && extra != NULL &&
      (extra->options & PCRE_STUDY_MAPPED) != 0 &&
      ((extra->options & PCRE_STUDY_CASELESS) != 0) == match_block.caseless)
        start_bits = extra->start_bits;
  }

/* Loop for unanchored matches; for anchored regexps the loop runs just once. */

do
  {
  register int *iptr = offsets;
  register int *iend = offsets + resetcount;

  /* Reset the maximum number of extractions we might see. */

  while (iptr < iend) *iptr++ = -1;

  /* Advance to a unique first char if possible */

  if (first_char >= 0)
    {
    if (match_block.caseless)
      while (start_match < end_subject && pcre_lcc[*start_match] != first_char)
        start_match++;
    else
      while (start_match < end_subject && *start_match != first_char)
        start_match++;
    }

  /* Or to just after \n for a multiline match if possible */

  else if (startline)
    {
    if (start_match > match_block.start_subject)
      {
      while (start_match < end_subject && start_match[-1] != '\n')
        start_match++;
      }
    }

  /* Or to a non-unique first char */

  else if (start_bits != NULL)
    {
    while (start_match < end_subject)
      {
      register int c = *start_match;
      if ((start_bits[c/8] & (1<<(c%8))) == 0) start_match++; else break;
      }
    }

  #ifdef DEBUG
  printf(">>>> Match against: ");
  pchars(start_match, end_subject - start_match, TRUE, &match_block);
  printf("\n");
  #endif

  /* When a match occurs, substrings will be set for all internal extractions;
  we just need to set up the whole thing as substring 0 before returning. If
  there were too many extractions, set the return code to zero. */

  if (match(start_match, re->code, 2, &match_block))
    {
    int rc = match_block.offset_overflow? 0 : match_block.end_offset_top/2;
    if (match_block.offset_end < 2) rc = 0; else
      {
      offsets[0] = start_match - match_block.start_subject;
      offsets[1] = match_block.end_match_ptr - match_block.start_subject;
      }
    #ifdef DEBUG
    printf(">>>> returning %d\n", rc);
    #endif
    free_stack(&match_block);
    return rc;
    }
  }
while (!anchored &&
       match_block.errorcode == PCRE_ERROR_NOMATCH &&
       start_match++ < end_subject);

#ifdef DEBUG
printf(">>>> returning %d\n", match_block.errorcode);
#endif
free_stack(&match_block);
return match_block.errorcode;
}

/* End of pcre.c */