/*
 * Secret Labs' Regular Expression Engine
 *
 * regular expression matching engine

  Copyright (c) 2015, Daryl McDaniel. All rights reserved.<BR>
  Copyright (c) 2011, Intel Corporation. All rights reserved.<BR>
  This program and the accompanying materials are licensed and made available under
  the terms and conditions of the BSD License that accompanies this distribution.
  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 *
 * partial history:
 * 1999-10-24 fl  created (based on existing template matcher code)
 * 2000-03-06 fl  first alpha, sort of
 * 2000-08-01 fl  fixes for 1.6b1
 * 2000-08-07 fl  use PyOS_CheckStack() if available
 * 2000-09-20 fl  added expand method
 * 2001-03-20 fl  lots of fixes for 2.1b2
 * 2001-04-15 fl  export copyright as Python attribute, not global
 * 2001-04-28 fl  added __copy__ methods (work in progress)
 * 2001-05-14 fl  fixes for 1.5.2 compatibility
 * 2001-07-01 fl  added BIGCHARSET support (from Martin von Loewis)
 * 2001-10-18 fl  fixed group reset issue (from Matthew Mueller)
 * 2001-10-20 fl  added split primitive; reenable unicode for 1.6/2.0/2.1
 * 2001-10-21 fl  added sub/subn primitive
 * 2001-10-24 fl  added finditer primitive (for 2.2 only)
 * 2001-12-07 fl  fixed memory leak in sub/subn (Guido van Rossum)
 * 2002-11-09 fl  fixed empty sub/subn return type
 * 2003-04-18 mvl fully support 4-byte codes
 * 2003-10-17 gn  implemented non recursive scheme
 *
 * Copyright (c) 1997-2001 by Secret Labs AB.  All rights reserved.
 *
 * This version of the SRE library can be redistributed under CNRI's
 * Python 1.6 license.  For any other use, please contact Secret Labs
 * AB (info@pythonware.com).
 *
 * Portions of this engine have been developed in cooperation with
 * CNRI.  Hewlett-Packard provided funding for 1.6 integration and
 * other compatibility work.
 */

/* Get rid of these macros to prevent collisions between EFI and Python in this file. */
#undef  RETURN_ERROR
#undef  RETURN_SUCCESS

#ifndef SRE_RECURSIVE

static char copyright[] =
    " SRE 2.2.2 Copyright (c) 1997-2002 by Secret Labs AB ";

#define PY_SSIZE_T_CLEAN

#include "Python.h"
#include "structmember.h" /* offsetof */

#include "sre.h"

#include <ctype.h>

/* name of this module, minus the leading underscore */
#if !defined(SRE_MODULE)
#define SRE_MODULE "sre"
#endif

#define SRE_PY_MODULE "re"

/* defining this one enables tracing */
#undef VERBOSE

#if PY_VERSION_HEX >= 0x01060000
#if PY_VERSION_HEX  < 0x02020000 || defined(Py_USING_UNICODE)
/* defining this enables unicode support (default under 1.6a1 and later) */
#define HAVE_UNICODE
#endif
#endif

/* -------------------------------------------------------------------- */
/* optional features */

/* enables fast searching */
#define USE_FAST_SEARCH

/* enables aggressive inlining (always on for Visual C) */
#undef USE_INLINE

/* enables copy/deepcopy handling (work in progress) */
#undef USE_BUILTIN_COPY

#if PY_VERSION_HEX < 0x01060000
#define PyObject_DEL(op) PyMem_DEL((op))
#endif

/* -------------------------------------------------------------------- */

#if defined(_MSC_VER)
#pragma optimize("gt", on) /* doesn't seem to make much difference... */
#pragma warning(disable: 4710) /* who cares if functions are not inlined ;-) */
/* fastest possible local call under MSVC */
#define LOCAL(type) static __inline type __fastcall
#elif defined(USE_INLINE)
#define LOCAL(type) static inline type
#else
#define LOCAL(type) static type
#endif

/* error codes */
#define SRE_ERROR_ILLEGAL -1 /* illegal opcode */
#define SRE_ERROR_STATE -2 /* illegal state */
#define SRE_ERROR_RECURSION_LIMIT -3 /* runaway recursion */
#define SRE_ERROR_MEMORY -9 /* out of memory */
#define SRE_ERROR_INTERRUPTED -10 /* signal handler raised exception */

#if defined(VERBOSE)
#define TRACE(v) printf v
#else
#define TRACE(v)
#endif

/* -------------------------------------------------------------------- */
/* search engine state */

/* default character predicates (run sre_chars.py to regenerate tables) */

#define SRE_DIGIT_MASK 1
#define SRE_SPACE_MASK 2
#define SRE_LINEBREAK_MASK 4
#define SRE_ALNUM_MASK 8
#define SRE_WORD_MASK 16

/* FIXME: this assumes ASCII.  create tables in init_sre() instead */

static char sre_char_info[128] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 6, 2,
2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 25, 25, 25, 25, 25, 25, 25, 25,
25, 25, 0, 0, 0, 0, 0, 0, 0, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 0, 0,
0, 0, 16, 0, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 0, 0, 0, 0, 0 };

static char sre_char_lower[128] = { 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 };

#define SRE_IS_DIGIT(ch)\
    ((ch) < 128 ? (sre_char_info[(ch)] & SRE_DIGIT_MASK) : 0)
#define SRE_IS_SPACE(ch)\
    ((ch) < 128 ? (sre_char_info[(ch)] & SRE_SPACE_MASK) : 0)
#define SRE_IS_LINEBREAK(ch)\
    ((ch) < 128 ? (sre_char_info[(ch)] & SRE_LINEBREAK_MASK) : 0)
#define SRE_IS_ALNUM(ch)\
    ((ch) < 128 ? (sre_char_info[(ch)] & SRE_ALNUM_MASK) : 0)
#define SRE_IS_WORD(ch)\
    ((ch) < 128 ? (sre_char_info[(ch)] & SRE_WORD_MASK) : 0)

static unsigned int sre_lower(unsigned int ch)
{
    return ((ch) < 128 ? (unsigned int)sre_char_lower[ch] : ch);
}

/* locale-specific character predicates */
/* !(c & ~N) == (c < N+1) for any unsigned c, this avoids
 * warnings when c's type supports only numbers < N+1 */
#define SRE_LOC_IS_DIGIT(ch) (!((ch) & ~255) ? isdigit((ch)) : 0)
#define SRE_LOC_IS_SPACE(ch) (!((ch) & ~255) ? isspace((ch)) : 0)
#define SRE_LOC_IS_LINEBREAK(ch) ((ch) == '\n')
#define SRE_LOC_IS_ALNUM(ch) (!((ch) & ~255) ? isalnum((ch)) : 0)
#define SRE_LOC_IS_WORD(ch) (SRE_LOC_IS_ALNUM((ch)) || (ch) == '_')

static unsigned int sre_lower_locale(unsigned int ch)
{
    return ((ch) < 256 ? (unsigned int)tolower((ch)) : ch);
}

/* unicode-specific character predicates */

#if defined(HAVE_UNICODE)

#define SRE_UNI_IS_DIGIT(ch) Py_UNICODE_ISDECIMAL((Py_UNICODE)(ch))
#define SRE_UNI_IS_SPACE(ch) Py_UNICODE_ISSPACE((Py_UNICODE)(ch))
#define SRE_UNI_IS_LINEBREAK(ch) Py_UNICODE_ISLINEBREAK((Py_UNICODE)(ch))
#define SRE_UNI_IS_ALNUM(ch) Py_UNICODE_ISALNUM((Py_UNICODE)(ch))
#define SRE_UNI_IS_WORD(ch) (SRE_UNI_IS_ALNUM((ch)) || (ch) == '_')

static unsigned int sre_lower_unicode(unsigned int ch)
{
    return (unsigned int) Py_UNICODE_TOLOWER((Py_UNICODE)(ch));
}

#endif

LOCAL(int)
sre_category(SRE_CODE category, unsigned int ch)
{
    switch (category) {

    case SRE_CATEGORY_DIGIT:
        return SRE_IS_DIGIT(ch);
    case SRE_CATEGORY_NOT_DIGIT:
        return !SRE_IS_DIGIT(ch);
    case SRE_CATEGORY_SPACE:
        return SRE_IS_SPACE(ch);
    case SRE_CATEGORY_NOT_SPACE:
        return !SRE_IS_SPACE(ch);
    case SRE_CATEGORY_WORD:
        return SRE_IS_WORD(ch);
    case SRE_CATEGORY_NOT_WORD:
        return !SRE_IS_WORD(ch);
    case SRE_CATEGORY_LINEBREAK:
        return SRE_IS_LINEBREAK(ch);
    case SRE_CATEGORY_NOT_LINEBREAK:
        return !SRE_IS_LINEBREAK(ch);

    case SRE_CATEGORY_LOC_WORD:
        return SRE_LOC_IS_WORD(ch);
    case SRE_CATEGORY_LOC_NOT_WORD:
        return !SRE_LOC_IS_WORD(ch);

#if defined(HAVE_UNICODE)
    case SRE_CATEGORY_UNI_DIGIT:
        return SRE_UNI_IS_DIGIT(ch);
    case SRE_CATEGORY_UNI_NOT_DIGIT:
        return !SRE_UNI_IS_DIGIT(ch);
    case SRE_CATEGORY_UNI_SPACE:
        return SRE_UNI_IS_SPACE(ch);
    case SRE_CATEGORY_UNI_NOT_SPACE:
        return !SRE_UNI_IS_SPACE(ch);
    case SRE_CATEGORY_UNI_WORD:
        return SRE_UNI_IS_WORD(ch);
    case SRE_CATEGORY_UNI_NOT_WORD:
        return !SRE_UNI_IS_WORD(ch);
    case SRE_CATEGORY_UNI_LINEBREAK:
        return SRE_UNI_IS_LINEBREAK(ch);
    case SRE_CATEGORY_UNI_NOT_LINEBREAK:
        return !SRE_UNI_IS_LINEBREAK(ch);
#else
    case SRE_CATEGORY_UNI_DIGIT:
        return SRE_IS_DIGIT(ch);
    case SRE_CATEGORY_UNI_NOT_DIGIT:
        return !SRE_IS_DIGIT(ch);
    case SRE_CATEGORY_UNI_SPACE:
        return SRE_IS_SPACE(ch);
    case SRE_CATEGORY_UNI_NOT_SPACE:
        return !SRE_IS_SPACE(ch);
    case SRE_CATEGORY_UNI_WORD:
        return SRE_LOC_IS_WORD(ch);
    case SRE_CATEGORY_UNI_NOT_WORD:
        return !SRE_LOC_IS_WORD(ch);
    case SRE_CATEGORY_UNI_LINEBREAK:
        return SRE_IS_LINEBREAK(ch);
    case SRE_CATEGORY_UNI_NOT_LINEBREAK:
        return !SRE_IS_LINEBREAK(ch);
#endif
    }
    return 0;
}

/* helpers */

static void
data_stack_dealloc(SRE_STATE* state)
{
    if (state->data_stack) {
        PyMem_FREE(state->data_stack);
        state->data_stack = NULL;
    }
    state->data_stack_size = state->data_stack_base = 0;
}

static int
data_stack_grow(SRE_STATE* state, Py_ssize_t size)
{
    Py_ssize_t minsize, cursize;
    minsize = state->data_stack_base+size;
    cursize = state->data_stack_size;
    if (cursize < minsize) {
        void* stack;
        cursize = minsize+minsize/4+1024;
        TRACE(("allocate/grow stack %" PY_FORMAT_SIZE_T "d\n", cursize));
        stack = PyMem_REALLOC(state->data_stack, cursize);
        if (!stack) {
            data_stack_dealloc(state);
            return SRE_ERROR_MEMORY;
        }
        state->data_stack = (char *)stack;
        state->data_stack_size = cursize;
    }
    return 0;
}

/* generate 8-bit version */

#define SRE_CHAR unsigned char
#define SRE_AT sre_at
#define SRE_COUNT sre_count
#define SRE_CHARSET sre_charset
#define SRE_INFO sre_info
#define SRE_MATCH sre_match
#define SRE_MATCH_CONTEXT sre_match_context
#define SRE_SEARCH sre_search
#define SRE_LITERAL_TEMPLATE sre_literal_template

#if defined(HAVE_UNICODE)

#define SRE_RECURSIVE
#include "_sre.c"
#undef SRE_RECURSIVE

#undef SRE_LITERAL_TEMPLATE
#undef SRE_SEARCH
#undef SRE_MATCH
#undef SRE_MATCH_CONTEXT
#undef SRE_INFO
#undef SRE_CHARSET
#undef SRE_COUNT
#undef SRE_AT
#undef SRE_CHAR

/* generate 16-bit unicode version */

#define SRE_CHAR Py_UNICODE
#define SRE_AT sre_uat
#define SRE_COUNT sre_ucount
#define SRE_CHARSET sre_ucharset
#define SRE_INFO sre_uinfo
#define SRE_MATCH sre_umatch
#define SRE_MATCH_CONTEXT sre_umatch_context
#define SRE_SEARCH sre_usearch
#define SRE_LITERAL_TEMPLATE sre_uliteral_template
#endif

#endif /* SRE_RECURSIVE */

/* -------------------------------------------------------------------- */
/* String matching engine */

/* the following section is compiled twice, with different character
   settings */

LOCAL(int)
SRE_AT(SRE_STATE* state, SRE_CHAR* ptr, SRE_CODE at)
{
    /* check if pointer is at given position */

    Py_ssize_t thisp, thatp;

    switch (at) {

    case SRE_AT_BEGINNING:
    case SRE_AT_BEGINNING_STRING:
        return ((void*) ptr == state->beginning);

    case SRE_AT_BEGINNING_LINE:
        return ((void*) ptr == state->beginning ||
                SRE_IS_LINEBREAK((int) ptr[-1]));

    case SRE_AT_END:
        return (((void*) (ptr+1) == state->end &&
                 SRE_IS_LINEBREAK((int) ptr[0])) ||
                ((void*) ptr == state->end));

    case SRE_AT_END_LINE:
        return ((void*) ptr == state->end ||
                SRE_IS_LINEBREAK((int) ptr[0]));

    case SRE_AT_END_STRING:
        return ((void*) ptr == state->end);

    case SRE_AT_BOUNDARY:
        if (state->beginning == state->end)
            return 0;
        thatp = ((void*) ptr > state->beginning) ?
            SRE_IS_WORD((int) ptr[-1]) : 0;
        thisp = ((void*) ptr < state->end) ?
            SRE_IS_WORD((int) ptr[0]) : 0;
        return thisp != thatp;

    case SRE_AT_NON_BOUNDARY:
        if (state->beginning == state->end)
            return 0;
        thatp = ((void*) ptr > state->beginning) ?
            SRE_IS_WORD((int) ptr[-1]) : 0;
        thisp = ((void*) ptr < state->end) ?
            SRE_IS_WORD((int) ptr[0]) : 0;
        return thisp == thatp;

    case SRE_AT_LOC_BOUNDARY:
        if (state->beginning == state->end)
            return 0;
        thatp = ((void*) ptr > state->beginning) ?
            SRE_LOC_IS_WORD((int) ptr[-1]) : 0;
        thisp = ((void*) ptr < state->end) ?
            SRE_LOC_IS_WORD((int) ptr[0]) : 0;
        return thisp != thatp;

    case SRE_AT_LOC_NON_BOUNDARY:
        if (state->beginning == state->end)
            return 0;
        thatp = ((void*) ptr > state->beginning) ?
            SRE_LOC_IS_WORD((int) ptr[-1]) : 0;
        thisp = ((void*) ptr < state->end) ?
            SRE_LOC_IS_WORD((int) ptr[0]) : 0;
        return thisp == thatp;

#if defined(HAVE_UNICODE)
    case SRE_AT_UNI_BOUNDARY:
        if (state->beginning == state->end)
            return 0;
        thatp = ((void*) ptr > state->beginning) ?
            SRE_UNI_IS_WORD((int) ptr[-1]) : 0;
        thisp = ((void*) ptr < state->end) ?
            SRE_UNI_IS_WORD((int) ptr[0]) : 0;
        return thisp != thatp;

    case SRE_AT_UNI_NON_BOUNDARY:
        if (state->beginning == state->end)
            return 0;
        thatp = ((void*) ptr > state->beginning) ?
            SRE_UNI_IS_WORD((int) ptr[-1]) : 0;
        thisp = ((void*) ptr < state->end) ?
            SRE_UNI_IS_WORD((int) ptr[0]) : 0;
        return thisp == thatp;
#endif

    }

    return 0;
}

LOCAL(int)
SRE_CHARSET(SRE_CODE* set, SRE_CODE ch)
{
    /* check if character is a member of the given set */

    int ok = 1;

    for (;;) {
        switch (*set++) {

        case SRE_OP_FAILURE:
            return !ok;

        case SRE_OP_LITERAL:
            /* <LITERAL> <code> */
            if (ch == set[0])
                return ok;
            set++;
            break;

        case SRE_OP_CATEGORY:
            /* <CATEGORY> <code> */
            if (sre_category(set[0], (int) ch))
                return ok;
            set += 1;
            break;

        case SRE_OP_CHARSET:
            if (sizeof(SRE_CODE) == 2) {
                /* <CHARSET> <bitmap> (16 bits per code word) */
                if (ch < 256 && (set[ch >> 4] & (1 << (ch & 15))))
                    return ok;
                set += 16;
            }
            else {
                /* <CHARSET> <bitmap> (32 bits per code word) */
                if (ch < 256 && (set[ch >> 5] & (1u << (ch & 31))))
                    return ok;
                set += 8;
            }
            break;

        case SRE_OP_RANGE:
            /* <RANGE> <lower> <upper> */
            if (set[0] <= ch && ch <= set[1])
                return ok;
            set += 2;
            break;

        case SRE_OP_NEGATE:
            ok = !ok;
            break;

        case SRE_OP_BIGCHARSET:
            /* <BIGCHARSET> <blockcount> <256 blockindices> <blocks> */
        {
            Py_ssize_t count, block;
            count = *(set++);

            if (sizeof(SRE_CODE) == 2) {
                block = ((unsigned char*)set)[ch >> 8];
                set += 128;
                if (set[block*16 + ((ch & 255)>>4)] & (1 << (ch & 15)))
                    return ok;
                set += count*16;
            }
            else {
                /* !(c & ~N) == (c < N+1) for any unsigned c, this avoids
                 * warnings when c's type supports only numbers < N+1 */
                if (!(ch & ~65535))
                    block = ((unsigned char*)set)[ch >> 8];
                else
                    block = -1;
                set += 64;
                if (block >=0 &&
                    (set[block*8 + ((ch & 255)>>5)] & (1u << (ch & 31))))
                    return ok;
                set += count*8;
            }
            break;
        }

        default:
            /* internal error -- there's not much we can do about it
               here, so let's just pretend it didn't match... */
            return 0;
        }
    }
}

LOCAL(Py_ssize_t) SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern);

LOCAL(Py_ssize_t)
SRE_COUNT(SRE_STATE* state, SRE_CODE* pattern, Py_ssize_t maxcount)
{
    SRE_CODE chr;
    SRE_CHAR* ptr = (SRE_CHAR *)state->ptr;
    SRE_CHAR* end = (SRE_CHAR *)state->end;
    Py_ssize_t i;

    /* adjust end */
    if (maxcount < end - ptr && maxcount != SRE_MAXREPEAT)
        end = ptr + maxcount;

    switch (pattern[0]) {

    case SRE_OP_IN:
        /* repeated set */
        TRACE(("|%p|%p|COUNT IN\n", pattern, ptr));
        while (ptr < end && SRE_CHARSET(pattern + 2, *ptr))
            ptr++;
        break;

    case SRE_OP_ANY:
        /* repeated dot wildcard. */
        TRACE(("|%p|%p|COUNT ANY\n", pattern, ptr));
        while (ptr < end && !SRE_IS_LINEBREAK(*ptr))
            ptr++;
        break;

    case SRE_OP_ANY_ALL:
        /* repeated dot wildcard.  skip to the end of the target
           string, and backtrack from there */
        TRACE(("|%p|%p|COUNT ANY_ALL\n", pattern, ptr));
        ptr = end;
        break;

    case SRE_OP_LITERAL:
        /* repeated literal */
        chr = pattern[1];
        TRACE(("|%p|%p|COUNT LITERAL %d\n", pattern, ptr, chr));
        while (ptr < end && (SRE_CODE) *ptr == chr)
            ptr++;
        break;

    case SRE_OP_LITERAL_IGNORE:
        /* repeated literal */
        chr = pattern[1];
        TRACE(("|%p|%p|COUNT LITERAL_IGNORE %d\n", pattern, ptr, chr));
        while (ptr < end && (SRE_CODE) state->lower(*ptr) == chr)
            ptr++;
        break;

    case SRE_OP_NOT_LITERAL:
        /* repeated non-literal */
        chr = pattern[1];
        TRACE(("|%p|%p|COUNT NOT_LITERAL %d\n", pattern, ptr, chr));
        while (ptr < end && (SRE_CODE) *ptr != chr)
            ptr++;
        break;

    case SRE_OP_NOT_LITERAL_IGNORE:
        /* repeated non-literal */
        chr = pattern[1];
        TRACE(("|%p|%p|COUNT NOT_LITERAL_IGNORE %d\n", pattern, ptr, chr));
        while (ptr < end && (SRE_CODE) state->lower(*ptr) != chr)
            ptr++;
        break;

    default:
        /* repeated single character pattern */
        TRACE(("|%p|%p|COUNT SUBPATTERN\n", pattern, ptr));
        while ((SRE_CHAR*) state->ptr < end) {
            i = SRE_MATCH(state, pattern);
            if (i < 0)
                return i;
            if (!i)
                break;
        }
        TRACE(("|%p|%p|COUNT %" PY_FORMAT_SIZE_T "d\n", pattern, ptr,
               (SRE_CHAR*) state->ptr - ptr));
        return (SRE_CHAR*) state->ptr - ptr;
    }

    TRACE(("|%p|%p|COUNT %" PY_FORMAT_SIZE_T "d\n", pattern, ptr,
           ptr - (SRE_CHAR*) state->ptr));
    return ptr - (SRE_CHAR*) state->ptr;
}

#if 0 /* not used in this release */
LOCAL(int)
SRE_INFO(SRE_STATE* state, SRE_CODE* pattern)
{
    /* check if an SRE_OP_INFO block matches at the current position.
       returns the number of SRE_CODE objects to skip if successful, 0
       if no match */

    SRE_CHAR* end = state->end;
    SRE_CHAR* ptr = state->ptr;
    Py_ssize_t i;

    /* check minimal length */
    if (pattern[3] && (end - ptr) < pattern[3])
        return 0;

    /* check known prefix */
    if (pattern[2] & SRE_INFO_PREFIX && pattern[5] > 1) {
        /* <length> <skip> <prefix data> <overlap data> */
        for (i = 0; i < pattern[5]; i++)
            if ((SRE_CODE) ptr[i] != pattern[7 + i])
                return 0;
        return pattern[0] + 2 * pattern[6];
    }
    return pattern[0];
}
#endif

/* The macros below should be used to protect recursive SRE_MATCH()
 * calls that *failed* and do *not* return immediately (IOW, those
 * that will backtrack). Explaining:
 *
 * - Recursive SRE_MATCH() returned true: that's usually a success
 *   (besides atypical cases like ASSERT_NOT), therefore there's no
 *   reason to restore lastmark;
 *
 * - Recursive SRE_MATCH() returned false but the current SRE_MATCH()
 *   is returning to the caller: If the current SRE_MATCH() is the
 *   top function of the recursion, returning false will be a matching
 *   failure, and it doesn't matter where lastmark is pointing to.
 *   If it's *not* the top function, it will be a recursive SRE_MATCH()
 *   failure by itself, and the calling SRE_MATCH() will have to deal
 *   with the failure by the same rules explained here (it will restore
 *   lastmark by itself if necessary);
 *
 * - Recursive SRE_MATCH() returned false, and will continue the
 *   outside 'for' loop: must be protected when breaking, since the next
 *   OP could potentially depend on lastmark;
 *
 * - Recursive SRE_MATCH() returned false, and will be called again
 *   inside a local for/while loop: must be protected between each
 *   loop iteration, since the recursive SRE_MATCH() could do anything,
 *   and could potentially depend on lastmark.
 *
 * For more information, check the discussion at SF patch #712900.
 */
#define LASTMARK_SAVE()     \
    do { \
        ctx->lastmark = state->lastmark; \
        ctx->lastindex = state->lastindex; \
    } while (0)
#define LASTMARK_RESTORE()  \
    do { \
        state->lastmark = ctx->lastmark; \
        state->lastindex = ctx->lastindex; \
    } while (0)

#define RETURN_ERROR(i) do { return i; } while(0)
#define RETURN_FAILURE do { ret = 0; goto exit; } while(0)
#define RETURN_SUCCESS do { ret = 1; goto exit; } while(0)

#define RETURN_ON_ERROR(i) \
    do { if (i < 0) RETURN_ERROR(i); } while (0)
#define RETURN_ON_SUCCESS(i) \
    do { RETURN_ON_ERROR(i); if (i > 0) RETURN_SUCCESS; } while (0)
#define RETURN_ON_FAILURE(i) \
    do { RETURN_ON_ERROR(i); if (i == 0) RETURN_FAILURE; } while (0)

#define SFY(x) #x

#define DATA_STACK_ALLOC(state, type, ptr) \
do { \
    alloc_pos = state->data_stack_base; \
    TRACE(("allocating %s in %" PY_FORMAT_SIZE_T "d " \
           "(%" PY_FORMAT_SIZE_T "d)\n", \
           SFY(type), alloc_pos, sizeof(type))); \
    if (sizeof(type) > state->data_stack_size - alloc_pos) { \
        int j = data_stack_grow(state, sizeof(type)); \
        if (j < 0) return j; \
        if (ctx_pos != -1) \
            DATA_STACK_LOOKUP_AT(state, SRE_MATCH_CONTEXT, ctx, ctx_pos); \
    } \
    ptr = (type*)(state->data_stack+alloc_pos); \
    state->data_stack_base += sizeof(type); \
} while (0)

#define DATA_STACK_LOOKUP_AT(state, type, ptr, pos) \
do { \
    TRACE(("looking up %s at %" PY_FORMAT_SIZE_T "d\n", SFY(type), pos)); \
    ptr = (type*)(state->data_stack+pos); \
} while (0)

#define DATA_STACK_PUSH(state, data, size) \
do { \
    TRACE(("copy data in %p to %" PY_FORMAT_SIZE_T "d " \
           "(%" PY_FORMAT_SIZE_T "d)\n", \
           data, state->data_stack_base, size)); \
    if (size > state->data_stack_size - state->data_stack_base) { \
        int j = data_stack_grow(state, size); \
        if (j < 0) return j; \
        if (ctx_pos != -1) \
            DATA_STACK_LOOKUP_AT(state, SRE_MATCH_CONTEXT, ctx, ctx_pos); \
    } \
    memcpy(state->data_stack+state->data_stack_base, data, size); \
    state->data_stack_base += size; \
} while (0)

#define DATA_STACK_POP(state, data, size, discard) \
do { \
    TRACE(("copy data to %p from %" PY_FORMAT_SIZE_T "d " \
           "(%" PY_FORMAT_SIZE_T "d)\n", \
           data, state->data_stack_base-size, size)); \
    memcpy(data, state->data_stack+state->data_stack_base-size, size); \
    if (discard) \
        state->data_stack_base -= size; \
} while (0)

#define DATA_STACK_POP_DISCARD(state, size) \
do { \
    TRACE(("discard data from %" PY_FORMAT_SIZE_T "d " \
           "(%" PY_FORMAT_SIZE_T "d)\n", \
           state->data_stack_base-size, size)); \
    state->data_stack_base -= size; \
} while(0)

#define DATA_PUSH(x) \
    DATA_STACK_PUSH(state, (x), sizeof(*(x)))
#define DATA_POP(x) \
    DATA_STACK_POP(state, (x), sizeof(*(x)), 1)
#define DATA_POP_DISCARD(x) \
    DATA_STACK_POP_DISCARD(state, sizeof(*(x)))
#define DATA_ALLOC(t,p) \
    DATA_STACK_ALLOC(state, t, p)
#define DATA_LOOKUP_AT(t,p,pos) \
    DATA_STACK_LOOKUP_AT(state,t,p,pos)

#define MARK_PUSH(lastmark) \
    do if (lastmark > 0) { \
        i = lastmark; /* ctx->lastmark may change if reallocated */ \
        DATA_STACK_PUSH(state, state->mark, (i+1)*sizeof(void*)); \
    } while (0)
#define MARK_POP(lastmark) \
    do if (lastmark > 0) { \
        DATA_STACK_POP(state, state->mark, (lastmark+1)*sizeof(void*), 1); \
    } while (0)
#define MARK_POP_KEEP(lastmark) \
    do if (lastmark > 0) { \
        DATA_STACK_POP(state, state->mark, (lastmark+1)*sizeof(void*), 0); \
    } while (0)
#define MARK_POP_DISCARD(lastmark) \
    do if (lastmark > 0) { \
        DATA_STACK_POP_DISCARD(state, (lastmark+1)*sizeof(void*)); \
    } while (0)

#define JUMP_NONE            0
#define JUMP_MAX_UNTIL_1     1
#define JUMP_MAX_UNTIL_2     2
#define JUMP_MAX_UNTIL_3     3
#define JUMP_MIN_UNTIL_1     4
#define JUMP_MIN_UNTIL_2     5
#define JUMP_MIN_UNTIL_3     6
#define JUMP_REPEAT          7
#define JUMP_REPEAT_ONE_1    8
#define JUMP_REPEAT_ONE_2    9
#define JUMP_MIN_REPEAT_ONE  10
#define JUMP_BRANCH          11
#define JUMP_ASSERT          12
#define JUMP_ASSERT_NOT      13

#define DO_JUMP(jumpvalue, jumplabel, nextpattern) \
    DATA_ALLOC(SRE_MATCH_CONTEXT, nextctx); \
    nextctx->last_ctx_pos = ctx_pos; \
    nextctx->jump = jumpvalue; \
    nextctx->pattern = nextpattern; \
    ctx_pos = alloc_pos; \
    ctx = nextctx; \
    goto entrance; \
    jumplabel: \
    while (0) /* gcc doesn't like labels at end of scopes */ \

typedef struct {
    Py_ssize_t last_ctx_pos;
    Py_ssize_t jump;
    SRE_CHAR* ptr;
    SRE_CODE* pattern;
    Py_ssize_t count;
    Py_ssize_t lastmark;
    Py_ssize_t lastindex;
    union {
        SRE_CODE chr;
        SRE_REPEAT* rep;
    } u;
} SRE_MATCH_CONTEXT;

/* check if string matches the given pattern.  returns <0 for
   error, 0 for failure, and 1 for success */
LOCAL(Py_ssize_t)
SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern)
{
    SRE_CHAR* end = (SRE_CHAR *)state->end;
    Py_ssize_t alloc_pos, ctx_pos = -1;
    Py_ssize_t i, ret = 0;
    Py_ssize_t jump;
    unsigned int sigcount=0;

    SRE_MATCH_CONTEXT* ctx;
    SRE_MATCH_CONTEXT* nextctx;

    TRACE(("|%p|%p|ENTER\n", pattern, state->ptr));

    DATA_ALLOC(SRE_MATCH_CONTEXT, ctx);
    ctx->last_ctx_pos = -1;
    ctx->jump = JUMP_NONE;
    ctx->pattern = pattern;
    ctx_pos = alloc_pos;

entrance:

    ctx->ptr = (SRE_CHAR *)state->ptr;

    if (ctx->pattern[0] == SRE_OP_INFO) {
        /* optimization info block */
        /* <INFO> <1=skip> <2=flags> <3=min> ... */
        if (ctx->pattern[3] && (end - ctx->ptr) < ctx->pattern[3]) {
            TRACE(("reject (got %" PY_FORMAT_SIZE_T "d chars, "
                   "need %" PY_FORMAT_SIZE_T "d)\n",
                   (end - ctx->ptr), (Py_ssize_t) ctx->pattern[3]));
            RETURN_FAILURE;
        }
        ctx->pattern += ctx->pattern[1] + 1;
    }

    for (;;) {
        ++sigcount;
        if ((0 == (sigcount & 0xfff)) && PyErr_CheckSignals())
            RETURN_ERROR(SRE_ERROR_INTERRUPTED);

        switch (*ctx->pattern++) {

        case SRE_OP_MARK:
            /* set mark */
            /* <MARK> <gid> */
            TRACE(("|%p|%p|MARK %d\n", ctx->pattern,
                   ctx->ptr, ctx->pattern[0]));
            i = ctx->pattern[0];
            if (i & 1)
                state->lastindex = i/2 + 1;
            if (i > state->lastmark) {
                /* state->lastmark is the highest valid index in the
                   state->mark array.  If it is increased by more than 1,
                   the intervening marks must be set to NULL to signal
                   that these marks have not been encountered. */
                Py_ssize_t j = state->lastmark + 1;
                while (j < i)
                    state->mark[j++] = NULL;
                state->lastmark = i;
            }
            state->mark[i] = ctx->ptr;
            ctx->pattern++;
            break;

        case SRE_OP_LITERAL:
            /* match literal string */
            /* <LITERAL> <code> */
            TRACE(("|%p|%p|LITERAL %d\n", ctx->pattern,
                   ctx->ptr, *ctx->pattern));
            if (ctx->ptr >= end || (SRE_CODE) ctx->ptr[0] != ctx->pattern[0])
                RETURN_FAILURE;
            ctx->pattern++;
            ctx->ptr++;
            break;

        case SRE_OP_NOT_LITERAL:
            /* match anything that is not literal character */
            /* <NOT_LITERAL> <code> */
            TRACE(("|%p|%p|NOT_LITERAL %d\n", ctx->pattern,
                   ctx->ptr, *ctx->pattern));
            if (ctx->ptr >= end || (SRE_CODE) ctx->ptr[0] == ctx->pattern[0])
                RETURN_FAILURE;
            ctx->pattern++;
            ctx->ptr++;
            break;

        case SRE_OP_SUCCESS:
            /* end of pattern */
            TRACE(("|%p|%p|SUCCESS\n", ctx->pattern, ctx->ptr));
            state->ptr = ctx->ptr;
            RETURN_SUCCESS;

        case SRE_OP_AT:
            /* match at given position */
            /* <AT> <code> */
            TRACE(("|%p|%p|AT %d\n", ctx->pattern, ctx->ptr, *ctx->pattern));
            if (!SRE_AT(state, ctx->ptr, *ctx->pattern))
                RETURN_FAILURE;
            ctx->pattern++;
            break;

        case SRE_OP_CATEGORY:
            /* match at given category */
            /* <CATEGORY> <code> */
            TRACE(("|%p|%p|CATEGORY %d\n", ctx->pattern,
                   ctx->ptr, *ctx->pattern));
            if (ctx->ptr >= end || !sre_category(ctx->pattern[0], ctx->ptr[0]))
                RETURN_FAILURE;
            ctx->pattern++;
            ctx->ptr++;
            break;

        case SRE_OP_ANY:
            /* match anything (except a newline) */
            /* <ANY> */
            TRACE(("|%p|%p|ANY\n", ctx->pattern, ctx->ptr));
            if (ctx->ptr >= end || SRE_IS_LINEBREAK(ctx->ptr[0]))
                RETURN_FAILURE;
            ctx->ptr++;
            break;

        case SRE_OP_ANY_ALL:
            /* match anything */
            /* <ANY_ALL> */
            TRACE(("|%p|%p|ANY_ALL\n", ctx->pattern, ctx->ptr));
            if (ctx->ptr >= end)
                RETURN_FAILURE;
            ctx->ptr++;
            break;

        case SRE_OP_IN:
            /* match set member (or non_member) */
            /* <IN> <skip> <set> */
            TRACE(("|%p|%p|IN\n", ctx->pattern, ctx->ptr));
            if (ctx->ptr >= end || !SRE_CHARSET(ctx->pattern + 1, *ctx->ptr))
                RETURN_FAILURE;
            ctx->pattern += ctx->pattern[0];
            ctx->ptr++;
            break;

        case SRE_OP_LITERAL_IGNORE:
            TRACE(("|%p|%p|LITERAL_IGNORE %d\n",
                   ctx->pattern, ctx->ptr, ctx->pattern[0]));
            if (ctx->ptr >= end ||
                state->lower(*ctx->ptr) != state->lower(*ctx->pattern))
                RETURN_FAILURE;
            ctx->pattern++;
            ctx->ptr++;
            break;

        case SRE_OP_NOT_LITERAL_IGNORE:
            TRACE(("|%p|%p|NOT_LITERAL_IGNORE %d\n",
                   ctx->pattern, ctx->ptr, *ctx->pattern));
            if (ctx->ptr >= end ||
                state->lower(*ctx->ptr) == state->lower(*ctx->pattern))
                RETURN_FAILURE;
            ctx->pattern++;
            ctx->ptr++;
            break;

        case SRE_OP_IN_IGNORE:
            TRACE(("|%p|%p|IN_IGNORE\n", ctx->pattern, ctx->ptr));
            if (ctx->ptr >= end
                || !SRE_CHARSET(ctx->pattern+1,
                                (SRE_CODE)state->lower(*ctx->ptr)))
                RETURN_FAILURE;
            ctx->pattern += ctx->pattern[0];
            ctx->ptr++;
            break;

        case SRE_OP_JUMP:
        case SRE_OP_INFO:
            /* jump forward */
            /* <JUMP> <offset> */
            TRACE(("|%p|%p|JUMP %d\n", ctx->pattern,
                   ctx->ptr, ctx->pattern[0]));
            ctx->pattern += ctx->pattern[0];
            break;

        case SRE_OP_BRANCH:
            /* alternation */
            /* <BRANCH> <0=skip> code <JUMP> ... <NULL> */
            TRACE(("|%p|%p|BRANCH\n", ctx->pattern, ctx->ptr));
            LASTMARK_SAVE();
            ctx->u.rep = state->repeat;
            if (ctx->u.rep)
                MARK_PUSH(ctx->lastmark);
            for (; ctx->pattern[0]; ctx->pattern += ctx->pattern[0]) {
                if (ctx->pattern[1] == SRE_OP_LITERAL &&
                    (ctx->ptr >= end ||
                     (SRE_CODE) *ctx->ptr != ctx->pattern[2]))
                    continue;
                if (ctx->pattern[1] == SRE_OP_IN &&
                    (ctx->ptr >= end ||
                     !SRE_CHARSET(ctx->pattern + 3, (SRE_CODE) *ctx->ptr)))
                    continue;
                state->ptr = ctx->ptr;
                DO_JUMP(JUMP_BRANCH, jump_branch, ctx->pattern+1);
                if (ret) {
                    if (ctx->u.rep)
                        MARK_POP_DISCARD(ctx->lastmark);
                    RETURN_ON_ERROR(ret);
                    RETURN_SUCCESS;
                }
                if (ctx->u.rep)
                    MARK_POP_KEEP(ctx->lastmark);
                LASTMARK_RESTORE();
            }
            if (ctx->u.rep)
                MARK_POP_DISCARD(ctx->lastmark);
            RETURN_FAILURE;

        case SRE_OP_REPEAT_ONE:
            /* match repeated sequence (maximizing regexp) */

            /* this operator only works if the repeated item is
               exactly one character wide, and we're not already
               collecting backtracking points.  for other cases,
               use the MAX_REPEAT operator */

            /* <REPEAT_ONE> <skip> <1=min> <2=max> item <SUCCESS> tail */

            TRACE(("|%p|%p|REPEAT_ONE %d %d\n", ctx->pattern, ctx->ptr,
                   ctx->pattern[1], ctx->pattern[2]));

            if ((Py_ssize_t) ctx->pattern[1] > end - ctx->ptr)
                RETURN_FAILURE; /* cannot match */

            state->ptr = ctx->ptr;

            ret = SRE_COUNT(state, ctx->pattern+3, ctx->pattern[2]);
            RETURN_ON_ERROR(ret);
            DATA_LOOKUP_AT(SRE_MATCH_CONTEXT, ctx, ctx_pos);
            ctx->count = ret;
            ctx->ptr += ctx->count;

            /* when we arrive here, count contains the number of
               matches, and ctx->ptr points to the tail of the target
               string.  check if the rest of the pattern matches,
               and backtrack if not. */

            if (ctx->count < (Py_ssize_t) ctx->pattern[1])
                RETURN_FAILURE;

            if (ctx->pattern[ctx->pattern[0]] == SRE_OP_SUCCESS) {
                /* tail is empty.  we're finished */
                state->ptr = ctx->ptr;
                RETURN_SUCCESS;
            }

            LASTMARK_SAVE();

            if (ctx->pattern[ctx->pattern[0]] == SRE_OP_LITERAL) {
                /* tail starts with a literal. skip positions where
                   the rest of the pattern cannot possibly match */
                ctx->u.chr = ctx->pattern[ctx->pattern[0]+1];
                for (;;) {
                    while (ctx->count >= (Py_ssize_t) ctx->pattern[1] &&
                           (ctx->ptr >= end || *ctx->ptr != ctx->u.chr)) {
                        ctx->ptr--;
                        ctx->count--;
                    }
                    if (ctx->count < (Py_ssize_t) ctx->pattern[1])
                        break;
                    state->ptr = ctx->ptr;
                    DO_JUMP(JUMP_REPEAT_ONE_1, jump_repeat_one_1,
                            ctx->pattern+ctx->pattern[0]);
                    if (ret) {
                        RETURN_ON_ERROR(ret);
                        RETURN_SUCCESS;
                    }

                    LASTMARK_RESTORE();

                    ctx->ptr--;
                    ctx->count--;
                }

            } else {
                /* general case */
                while (ctx->count >= (Py_ssize_t) ctx->pattern[1]) {
                    state->ptr = ctx->ptr;
                    DO_JUMP(JUMP_REPEAT_ONE_2, jump_repeat_one_2,
                            ctx->pattern+ctx->pattern[0]);
                    if (ret) {
                        RETURN_ON_ERROR(ret);
                        RETURN_SUCCESS;
                    }
                    ctx->ptr--;
                    ctx->count--;
                    LASTMARK_RESTORE();
                }
            }
            RETURN_FAILURE;

        case SRE_OP_MIN_REPEAT_ONE:
            /* match repeated sequence (minimizing regexp) */

            /* this operator only works if the repeated item is
               exactly one character wide, and we're not already
               collecting backtracking points.  for other cases,
               use the MIN_REPEAT operator */

            /* <MIN_REPEAT_ONE> <skip> <1=min> <2=max> item <SUCCESS> tail */

            TRACE(("|%p|%p|MIN_REPEAT_ONE %d %d\n", ctx->pattern, ctx->ptr,
                   ctx->pattern[1], ctx->pattern[2]));

            if ((Py_ssize_t) ctx->pattern[1] > end - ctx->ptr)
                RETURN_FAILURE; /* cannot match */

            state->ptr = ctx->ptr;

            if (ctx->pattern[1] == 0)
                ctx->count = 0;
            else {
                /* count using pattern min as the maximum */
                ret = SRE_COUNT(state, ctx->pattern+3, ctx->pattern[1]);
                RETURN_ON_ERROR(ret);
                DATA_LOOKUP_AT(SRE_MATCH_CONTEXT, ctx, ctx_pos);
                if (ret < (Py_ssize_t) ctx->pattern[1])
                    /* didn't match minimum number of times */
                    RETURN_FAILURE;
                /* advance past minimum matches of repeat */
                ctx->count = ret;
                ctx->ptr += ctx->count;
            }

            if (ctx->pattern[ctx->pattern[0]] == SRE_OP_SUCCESS) {
                /* tail is empty.  we're finished */
                state->ptr = ctx->ptr;
                RETURN_SUCCESS;

            } else {
                /* general case */
                LASTMARK_SAVE();
                while ((Py_ssize_t)ctx->pattern[2] == SRE_MAXREPEAT
                       || ctx->count <= (Py_ssize_t)ctx->pattern[2]) {
                    state->ptr = ctx->ptr;
                    DO_JUMP(JUMP_MIN_REPEAT_ONE,jump_min_repeat_one,
                            ctx->pattern+ctx->pattern[0]);
                    if (ret) {
                        RETURN_ON_ERROR(ret);
                        RETURN_SUCCESS;
                    }
                    state->ptr = ctx->ptr;
                    ret = SRE_COUNT(state, ctx->pattern+3, 1);
                    RETURN_ON_ERROR(ret);
                    DATA_LOOKUP_AT(SRE_MATCH_CONTEXT, ctx, ctx_pos);
                    if (ret == 0)
                        break;
                    assert(ret == 1);
                    ctx->ptr++;
                    ctx->count++;
                    LASTMARK_RESTORE();
                }
            }
            RETURN_FAILURE;

        case SRE_OP_REPEAT:
            /* create repeat context.  all the hard work is done
               by the UNTIL operator (MAX_UNTIL, MIN_UNTIL) */
            /* <REPEAT> <skip> <1=min> <2=max> item <UNTIL> tail */
            TRACE(("|%p|%p|REPEAT %d %d\n", ctx->pattern, ctx->ptr,
                   ctx->pattern[1], ctx->pattern[2]));

            /* install new repeat context */
            ctx->u.rep = (SRE_REPEAT*) PyObject_MALLOC(sizeof(*ctx->u.rep));
            if (!ctx->u.rep) {
                PyErr_NoMemory();
                RETURN_FAILURE;
            }
            ctx->u.rep->count = -1;
            ctx->u.rep->pattern = ctx->pattern;
            ctx->u.rep->prev = state->repeat;
            ctx->u.rep->last_ptr = NULL;
            state->repeat = ctx->u.rep;

            state->ptr = ctx->ptr;
            DO_JUMP(JUMP_REPEAT, jump_repeat, ctx->pattern+ctx->pattern[0]);
            state->repeat = ctx->u.rep->prev;
            PyObject_FREE(ctx->u.rep);

            if (ret) {
                RETURN_ON_ERROR(ret);
                RETURN_SUCCESS;
            }
            RETURN_FAILURE;

        case SRE_OP_MAX_UNTIL:
            /* maximizing repeat */
            /* <REPEAT> <skip> <1=min> <2=max> item <MAX_UNTIL> tail */

            /* FIXME: we probably need to deal with zero-width
               matches in here... */

            ctx->u.rep = state->repeat;
            if (!ctx->u.rep)
                RETURN_ERROR(SRE_ERROR_STATE);

            state->ptr = ctx->ptr;

            ctx->count = ctx->u.rep->count+1;

            TRACE(("|%p|%p|MAX_UNTIL %" PY_FORMAT_SIZE_T "d\n", ctx->pattern,
                   ctx->ptr, ctx->count));

            if (ctx->count < (Py_ssize_t) ctx->u.rep->pattern[1]) {
                /* not enough matches */
                ctx->u.rep->count = ctx->count;
                DO_JUMP(JUMP_MAX_UNTIL_1, jump_max_until_1,
                        ctx->u.rep->pattern+3);
                if (ret) {
                    RETURN_ON_ERROR(ret);
                    RETURN_SUCCESS;
                }
                ctx->u.rep->count = ctx->count-1;
                state->ptr = ctx->ptr;
                RETURN_FAILURE;
            }

            if ((ctx->count < (Py_ssize_t) ctx->u.rep->pattern[2] ||
                ctx->u.rep->pattern[2] == SRE_MAXREPEAT) &&
                state->ptr != ctx->u.rep->last_ptr) {
                /* we may have enough matches, but if we can
                   match another item, do so */
                ctx->u.rep->count = ctx->count;
                LASTMARK_SAVE();
                MARK_PUSH(ctx->lastmark);
                /* zero-width match protection */
                DATA_PUSH(&ctx->u.rep->last_ptr);
                ctx->u.rep->last_ptr = state->ptr;
                DO_JUMP(JUMP_MAX_UNTIL_2, jump_max_until_2,
                        ctx->u.rep->pattern+3);
                DATA_POP(&ctx->u.rep->last_ptr);
                if (ret) {
                    MARK_POP_DISCARD(ctx->lastmark);
                    RETURN_ON_ERROR(ret);
                    RETURN_SUCCESS;
                }
                MARK_POP(ctx->lastmark);
                LASTMARK_RESTORE();
                ctx->u.rep->count = ctx->count-1;
                state->ptr = ctx->ptr;
            }

            /* cannot match more repeated items here.  make sure the
               tail matches */
            state->repeat = ctx->u.rep->prev;
            DO_JUMP(JUMP_MAX_UNTIL_3, jump_max_until_3, ctx->pattern);
            RETURN_ON_SUCCESS(ret);
            state->repeat = ctx->u.rep;
            state->ptr = ctx->ptr;
            RETURN_FAILURE;

        case SRE_OP_MIN_UNTIL:
            /* minimizing repeat */
            /* <REPEAT> <skip> <1=min> <2=max> item <MIN_UNTIL> tail */

            ctx->u.rep = state->repeat;
            if (!ctx->u.rep)
                RETURN_ERROR(SRE_ERROR_STATE);

            state->ptr = ctx->ptr;

            ctx->count = ctx->u.rep->count+1;

            TRACE(("|%p|%p|MIN_UNTIL %" PY_FORMAT_SIZE_T "d %p\n", ctx->pattern,
                   ctx->ptr, ctx->count, ctx->u.rep->pattern));

            if (ctx->count < (Py_ssize_t) ctx->u.rep->pattern[1]) {
                /* not enough matches */
                ctx->u.rep->count = ctx->count;
                DO_JUMP(JUMP_MIN_UNTIL_1, jump_min_until_1,
                        ctx->u.rep->pattern+3);
                if (ret) {
                    RETURN_ON_ERROR(ret);
                    RETURN_SUCCESS;
                }
                ctx->u.rep->count = ctx->count-1;
                state->ptr = ctx->ptr;
                RETURN_FAILURE;
            }

            LASTMARK_SAVE();

            /* see if the tail matches */
            state->repeat = ctx->u.rep->prev;
            DO_JUMP(JUMP_MIN_UNTIL_2, jump_min_until_2, ctx->pattern);
            if (ret) {
                RETURN_ON_ERROR(ret);
                RETURN_SUCCESS;
            }

            state->repeat = ctx->u.rep;
            state->ptr = ctx->ptr;

            LASTMARK_RESTORE();

            if ((ctx->count >= (Py_ssize_t) ctx->u.rep->pattern[2]
                && ctx->u.rep->pattern[2] != SRE_MAXREPEAT) ||
                state->ptr == ctx->u.rep->last_ptr)
                RETURN_FAILURE;

            ctx->u.rep->count = ctx->count;
            /* zero-width match protection */
            DATA_PUSH(&ctx->u.rep->last_ptr);
            ctx->u.rep->last_ptr = state->ptr;
            DO_JUMP(JUMP_MIN_UNTIL_3,jump_min_until_3,
                    ctx->u.rep->pattern+3);
            DATA_POP(&ctx->u.rep->last_ptr);
            if (ret) {
                RETURN_ON_ERROR(ret);
                RETURN_SUCCESS;
            }
            ctx->u.rep->count = ctx->count-1;
            state->ptr = ctx->ptr;
            RETURN_FAILURE;

        case SRE_OP_GROUPREF:
            /* match backreference */
            TRACE(("|%p|%p|GROUPREF %d\n", ctx->pattern,
                   ctx->ptr, ctx->pattern[0]));
            i = ctx->pattern[0];
            {
                Py_ssize_t groupref = i+i;
                if (groupref >= state->lastmark) {
                    RETURN_FAILURE;
                } else {
                    SRE_CHAR* p = (SRE_CHAR*) state->mark[groupref];
                    SRE_CHAR* e = (SRE_CHAR*) state->mark[groupref+1];
                    if (!p || !e || e < p)
                        RETURN_FAILURE;
                    while (p < e) {
                        if (ctx->ptr >= end || *ctx->ptr != *p)
                            RETURN_FAILURE;
                        p++; ctx->ptr++;
                    }
                }
            }
            ctx->pattern++;
            break;

        case SRE_OP_GROUPREF_IGNORE:
            /* match backreference */
            TRACE(("|%p|%p|GROUPREF_IGNORE %d\n", ctx->pattern,
                   ctx->ptr, ctx->pattern[0]));
            i = ctx->pattern[0];
            {
                Py_ssize_t groupref = i+i;
                if (groupref >= state->lastmark) {
                    RETURN_FAILURE;
                } else {
                    SRE_CHAR* p = (SRE_CHAR*) state->mark[groupref];
                    SRE_CHAR* e = (SRE_CHAR*) state->mark[groupref+1];
                    if (!p || !e || e < p)
                        RETURN_FAILURE;
                    while (p < e) {
                        if (ctx->ptr >= end ||
                            state->lower(*ctx->ptr) != state->lower(*p))
                            RETURN_FAILURE;
                        p++; ctx->ptr++;
                    }
                }
            }
            ctx->pattern++;
            break;

        case SRE_OP_GROUPREF_EXISTS:
            TRACE(("|%p|%p|GROUPREF_EXISTS %d\n", ctx->pattern,
                   ctx->ptr, ctx->pattern[0]));
            /* <GROUPREF_EXISTS> <group> <skip> codeyes <JUMP> codeno ... */
            i = ctx->pattern[0];
            {
                Py_ssize_t groupref = i+i;
                if (groupref >= state->lastmark) {
                    ctx->pattern += ctx->pattern[1];
                    break;
                } else {
                    SRE_CHAR* p = (SRE_CHAR*) state->mark[groupref];
                    SRE_CHAR* e = (SRE_CHAR*) state->mark[groupref+1];
                    if (!p || !e || e < p) {
                        ctx->pattern += ctx->pattern[1];
                        break;
                    }
                }
            }
            ctx->pattern += 2;
            break;

        case SRE_OP_ASSERT:
            /* assert subpattern */
            /* <ASSERT> <skip> <back> <pattern> */
            TRACE(("|%p|%p|ASSERT %d\n", ctx->pattern,
                   ctx->ptr, ctx->pattern[1]));
            state->ptr = ctx->ptr - ctx->pattern[1];
            if (state->ptr < state->beginning)
                RETURN_FAILURE;
            DO_JUMP(JUMP_ASSERT, jump_assert, ctx->pattern+2);
            RETURN_ON_FAILURE(ret);
            ctx->pattern += ctx->pattern[0];
            break;

        case SRE_OP_ASSERT_NOT:
            /* assert not subpattern */
            /* <ASSERT_NOT> <skip> <back> <pattern> */
            TRACE(("|%p|%p|ASSERT_NOT %d\n", ctx->pattern,
                   ctx->ptr, ctx->pattern[1]));
            state->ptr = ctx->ptr - ctx->pattern[1];
            if (state->ptr >= state->beginning) {
                DO_JUMP(JUMP_ASSERT_NOT, jump_assert_not, ctx->pattern+2);
                if (ret) {
                    RETURN_ON_ERROR(ret);
                    RETURN_FAILURE;
                }
            }
            ctx->pattern += ctx->pattern[0];
            break;

        case SRE_OP_FAILURE:
            /* immediate failure */
            TRACE(("|%p|%p|FAILURE\n", ctx->pattern, ctx->ptr));
            RETURN_FAILURE;

        default:
            TRACE(("|%p|%p|UNKNOWN %d\n", ctx->pattern, ctx->ptr,
                   ctx->pattern[-1]));
            RETURN_ERROR(SRE_ERROR_ILLEGAL);
        }
    }

exit:
    ctx_pos = ctx->last_ctx_pos;
    jump = ctx->jump;
    DATA_POP_DISCARD(ctx);
    if (ctx_pos == -1)
        return ret;
    DATA_LOOKUP_AT(SRE_MATCH_CONTEXT, ctx, ctx_pos);

    switch (jump) {
        case JUMP_MAX_UNTIL_2:
            TRACE(("|%p|%p|JUMP_MAX_UNTIL_2\n", ctx->pattern, ctx->ptr));
            goto jump_max_until_2;
        case JUMP_MAX_UNTIL_3:
            TRACE(("|%p|%p|JUMP_MAX_UNTIL_3\n", ctx->pattern, ctx->ptr));
            goto jump_max_until_3;
        case JUMP_MIN_UNTIL_2:
            TRACE(("|%p|%p|JUMP_MIN_UNTIL_2\n", ctx->pattern, ctx->ptr));
            goto jump_min_until_2;
        case JUMP_MIN_UNTIL_3:
            TRACE(("|%p|%p|JUMP_MIN_UNTIL_3\n", ctx->pattern, ctx->ptr));
            goto jump_min_until_3;
        case JUMP_BRANCH:
            TRACE(("|%p|%p|JUMP_BRANCH\n", ctx->pattern, ctx->ptr));
            goto jump_branch;
        case JUMP_MAX_UNTIL_1:
            TRACE(("|%p|%p|JUMP_MAX_UNTIL_1\n", ctx->pattern, ctx->ptr));
            goto jump_max_until_1;
        case JUMP_MIN_UNTIL_1:
            TRACE(("|%p|%p|JUMP_MIN_UNTIL_1\n", ctx->pattern, ctx->ptr));
            goto jump_min_until_1;
        case JUMP_REPEAT:
            TRACE(("|%p|%p|JUMP_REPEAT\n", ctx->pattern, ctx->ptr));
            goto jump_repeat;
        case JUMP_REPEAT_ONE_1:
            TRACE(("|%p|%p|JUMP_REPEAT_ONE_1\n", ctx->pattern, ctx->ptr));
            goto jump_repeat_one_1;
        case JUMP_REPEAT_ONE_2:
            TRACE(("|%p|%p|JUMP_REPEAT_ONE_2\n", ctx->pattern, ctx->ptr));
            goto jump_repeat_one_2;
        case JUMP_MIN_REPEAT_ONE:
            TRACE(("|%p|%p|JUMP_MIN_REPEAT_ONE\n", ctx->pattern, ctx->ptr));
            goto jump_min_repeat_one;
        case JUMP_ASSERT:
            TRACE(("|%p|%p|JUMP_ASSERT\n", ctx->pattern, ctx->ptr));
            goto jump_assert;
        case JUMP_ASSERT_NOT:
            TRACE(("|%p|%p|JUMP_ASSERT_NOT\n", ctx->pattern, ctx->ptr));
            goto jump_assert_not;
        case JUMP_NONE:
            TRACE(("|%p|%p|RETURN %" PY_FORMAT_SIZE_T "d\n", ctx->pattern,
                   ctx->ptr, ret));
            break;
    }

    return ret; /* should never get here */
}

LOCAL(Py_ssize_t)
SRE_SEARCH(SRE_STATE* state, SRE_CODE* pattern)
{
    SRE_CHAR* ptr = (SRE_CHAR *)state->start;
    SRE_CHAR* end = (SRE_CHAR *)state->end;
    Py_ssize_t status = 0;
    Py_ssize_t prefix_len = 0;
    Py_ssize_t prefix_skip = 0;
    SRE_CODE* prefix = NULL;
    SRE_CODE* charset = NULL;
    SRE_CODE* overlap = NULL;
    int flags = 0;

    if (pattern[0] == SRE_OP_INFO) {
        /* optimization info block */
        /* <INFO> <1=skip> <2=flags> <3=min> <4=max> <5=prefix info>  */

        flags = pattern[2];

        if (pattern[3] > 1) {
            /* adjust end point (but make sure we leave at least one
               character in there, so literal search will work) */
            end -= pattern[3]-1;
            if (end <= ptr)
                end = ptr+1;
        }

        if (flags & SRE_INFO_PREFIX) {
            /* pattern starts with a known prefix */
            /* <length> <skip> <prefix data> <overlap data> */
            prefix_len = pattern[5];
            prefix_skip = pattern[6];
            prefix = pattern + 7;
            overlap = prefix + prefix_len - 1;
        } else if (flags & SRE_INFO_CHARSET)
            /* pattern starts with a character from a known set */
            /* <charset> */
            charset = pattern + 5;

        pattern += 1 + pattern[1];
    }

    TRACE(("prefix = %p %" PY_FORMAT_SIZE_T "d %" PY_FORMAT_SIZE_T "d\n",
           prefix, prefix_len, prefix_skip));
    TRACE(("charset = %p\n", charset));

#if defined(USE_FAST_SEARCH)
    if (prefix_len > 1) {
        /* pattern starts with a known prefix.  use the overlap
           table to skip forward as fast as we possibly can */
        Py_ssize_t i = 0;
        end = (SRE_CHAR *)state->end;
        while (ptr < end) {
            for (;;) {
                if ((SRE_CODE) ptr[0] != prefix[i]) {
                    if (!i)
                        break;
                    else
                        i = overlap[i];
                } else {
                    if (++i == prefix_len) {
                        /* found a potential match */
                        TRACE(("|%p|%p|SEARCH SCAN\n", pattern, ptr));
                        state->start = ptr + 1 - prefix_len;
                        state->ptr = ptr + 1 - prefix_len + prefix_skip;
                        if (flags & SRE_INFO_LITERAL)
                            return 1; /* we got all of it */
                        status = SRE_MATCH(state, pattern + 2*prefix_skip);
                        if (status != 0)
                            return status;
                        /* close but no cigar -- try again */
                        i = overlap[i];
                    }
                    break;
                }
            }
            ptr++;
        }
        return 0;
    }
#endif

    if (pattern[0] == SRE_OP_LITERAL) {
        /* pattern starts with a literal character.  this is used
           for short prefixes, and if fast search is disabled */
        SRE_CODE chr = pattern[1];
        end = (SRE_CHAR *)state->end;
        for (;;) {
            while (ptr < end && (SRE_CODE) ptr[0] != chr)
                ptr++;
            if (ptr >= end)
                return 0;
            TRACE(("|%p|%p|SEARCH LITERAL\n", pattern, ptr));
            state->start = ptr;
            state->ptr = ++ptr;
            if (flags & SRE_INFO_LITERAL)
                return 1; /* we got all of it */
            status = SRE_MATCH(state, pattern + 2);
            if (status != 0)
                break;
        }
    } else if (charset) {
        /* pattern starts with a character from a known set */
        end = (SRE_CHAR *)state->end;
        for (;;) {
            while (ptr < end && !SRE_CHARSET(charset, ptr[0]))
                ptr++;
            if (ptr >= end)
                return 0;
            TRACE(("|%p|%p|SEARCH CHARSET\n", pattern, ptr));
            state->start = ptr;
            state->ptr = ptr;
            status = SRE_MATCH(state, pattern);
            if (status != 0)
                break;
            ptr++;
        }
    } else
        /* general case */
        while (ptr <= end) {
            TRACE(("|%p|%p|SEARCH\n", pattern, ptr));
            state->start = state->ptr = ptr++;
            status = SRE_MATCH(state, pattern);
            if (status != 0)
                break;
        }

    return status;
}

LOCAL(int)
SRE_LITERAL_TEMPLATE(SRE_CHAR* ptr, Py_ssize_t len)
{
    /* check if given string is a literal template (i.e. no escapes) */
    while (len-- > 0)
        if (*ptr++ == '\\')
            return 0;
    return 1;
}

#if !defined(SRE_RECURSIVE)

/* -------------------------------------------------------------------- */
/* factories and destructors */

/* see sre.h for object declarations */
static PyObject*pattern_new_match(PatternObject*, SRE_STATE*, int);
static PyObject*pattern_scanner(PatternObject*, PyObject*);

static PyObject *
sre_codesize(PyObject* self, PyObject *unused)
{
    return PyInt_FromSize_t(sizeof(SRE_CODE));
}

static PyObject *
sre_getlower(PyObject* self, PyObject* args)
{
    int character, flags;
    if (!PyArg_ParseTuple(args, "ii", &character, &flags))
        return NULL;
    if (flags & SRE_FLAG_LOCALE)
        return Py_BuildValue("i", sre_lower_locale(character));
    if (flags & SRE_FLAG_UNICODE)
#if defined(HAVE_UNICODE)
        return Py_BuildValue("i", sre_lower_unicode(character));
#else
        return Py_BuildValue("i", sre_lower_locale(character));
#endif
    return Py_BuildValue("i", sre_lower(character));
}

LOCAL(void)
state_reset(SRE_STATE* state)
{
    /* FIXME: dynamic! */
    /*memset(state->mark, 0, sizeof(*state->mark) * SRE_MARK_SIZE);*/

    state->lastmark = -1;
    state->lastindex = -1;

    state->repeat = NULL;

    data_stack_dealloc(state);
}

static void*
getstring(PyObject* string, Py_ssize_t* p_length, int* p_charsize)
{
    /* given a python object, return a data pointer, a length (in
       characters), and a character size.  return NULL if the object
       is not a string (or not compatible) */

    PyBufferProcs *buffer;
    Py_ssize_t size, bytes;
    int charsize;
    void* ptr;

#if defined(HAVE_UNICODE)
    if (PyUnicode_Check(string)) {
        /* unicode strings doesn't always support the buffer interface */
        ptr = (void*) PyUnicode_AS_DATA(string);
        /* bytes = PyUnicode_GET_DATA_SIZE(string); */
        size = PyUnicode_GET_SIZE(string);
        charsize = sizeof(Py_UNICODE);

    } else {
#endif

    /* get pointer to string buffer */
    buffer = Py_TYPE(string)->tp_as_buffer;
    if (!buffer || !buffer->bf_getreadbuffer || !buffer->bf_getsegcount ||
        buffer->bf_getsegcount(string, NULL) != 1) {
        PyErr_SetString(PyExc_TypeError, "expected string or buffer");
        return NULL;
    }

    /* determine buffer size */
    bytes = buffer->bf_getreadbuffer(string, 0, &ptr);
    if (bytes < 0) {
        PyErr_SetString(PyExc_TypeError, "buffer has negative size");
        return NULL;
    }

    /* determine character size */
#if PY_VERSION_HEX >= 0x01060000
    size = PyObject_Size(string);
#else
    size = PyObject_Length(string);
#endif

    if (PyString_Check(string) || bytes == size)
        charsize = 1;
#if defined(HAVE_UNICODE)
    else if (bytes == (Py_ssize_t) (size * sizeof(Py_UNICODE)))
        charsize = sizeof(Py_UNICODE);
#endif
    else {
        PyErr_SetString(PyExc_TypeError, "buffer size mismatch");
        return NULL;
    }

#if defined(HAVE_UNICODE)
    }
#endif

    *p_length = size;
    *p_charsize = charsize;

    return ptr;
}

LOCAL(PyObject*)
state_init(SRE_STATE* state, PatternObject* pattern, PyObject* string,
           Py_ssize_t start, Py_ssize_t end)
{
    /* prepare state object */

    Py_ssize_t length;
    int charsize;
    void* ptr;

    memset(state, 0, sizeof(SRE_STATE));

    state->lastmark = -1;
    state->lastindex = -1;

    ptr = getstring(string, &length, &charsize);
    if (!ptr)
        return NULL;

    /* adjust boundaries */
    if (start < 0)
        start = 0;
    else if (start > length)
        start = length;

    if (end < 0)
        end = 0;
    else if (end > length)
        end = length;

    state->charsize = charsize;

    state->beginning = ptr;

    state->start = (void*) ((char*) ptr + start * state->charsize);
    state->end = (void*) ((char*) ptr + end * state->charsize);

    Py_INCREF(string);
    state->string = string;
    state->pos = start;
    state->endpos = end;

    if (pattern->flags & SRE_FLAG_LOCALE)
        state->lower = sre_lower_locale;
    else if (pattern->flags & SRE_FLAG_UNICODE)
#if defined(HAVE_UNICODE)
        state->lower = sre_lower_unicode;
#else
        state->lower = sre_lower_locale;
#endif
    else
        state->lower = sre_lower;

    return string;
}

LOCAL(void)
state_fini(SRE_STATE* state)
{
    Py_XDECREF(state->string);
    data_stack_dealloc(state);
}

/* calculate offset from start of string */
#define STATE_OFFSET(state, member)\
    (((char*)(member) - (char*)(state)->beginning) / (state)->charsize)

LOCAL(PyObject*)
state_getslice(SRE_STATE* state, Py_ssize_t index, PyObject* string, int empty)
{
    Py_ssize_t i, j;

    index = (index - 1) * 2;

    if (string == Py_None || index >= state->lastmark || !state->mark[index] || !state->mark[index+1]) {
        if (empty)
            /* want empty string */
            i = j = 0;
        else {
            Py_INCREF(Py_None);
            return Py_None;
        }
    } else {
        i = STATE_OFFSET(state, state->mark[index]);
        j = STATE_OFFSET(state, state->mark[index+1]);
    }

    return PySequence_GetSlice(string, i, j);
}

static void
pattern_error(int status)
{
    switch (status) {
    case SRE_ERROR_RECURSION_LIMIT:
        PyErr_SetString(
            PyExc_RuntimeError,
            "maximum recursion limit exceeded"
            );
        break;
    case SRE_ERROR_MEMORY:
        PyErr_NoMemory();
        break;
    case SRE_ERROR_INTERRUPTED:
    /* An exception has already been raised, so let it fly */
        break;
    default:
        /* other error codes indicate compiler/engine bugs */
        PyErr_SetString(
            PyExc_RuntimeError,
            "internal error in regular expression engine"
            );
    }
}

static void
pattern_dealloc(PatternObject* self)
{
    if (self->weakreflist != NULL)
        PyObject_ClearWeakRefs((PyObject *) self);
    Py_XDECREF(self->pattern);
    Py_XDECREF(self->groupindex);
    Py_XDECREF(self->indexgroup);
    PyObject_DEL(self);
}

static int
check_args_size(const char *name, PyObject* args, PyObject* kw, int n)
{
    Py_ssize_t m = PyTuple_GET_SIZE(args) + (kw ? PyDict_Size(kw) : 0);
    if (m <= n)
        return 1;
    PyErr_Format(PyExc_TypeError,
                 "%s() takes at most %d positional arguments (%zd given)",
                 name, n, m);
    return 0;
}

static PyObject*
fix_string_param(PyObject *string, PyObject *string2, const char *oldname)
{
    if (string2 != NULL) {
        char buf[100];
        if (string != NULL) {
            PyErr_Format(PyExc_TypeError,
                         "Argument given by name ('%s') and position (1)",
                         oldname);
            return NULL;
        }
        sprintf(buf, "The '%s' keyword parameter name is deprecated.  "
                     "Use 'string' instead.", oldname);
        if (PyErr_Warn(PyExc_DeprecationWarning, buf) < 0)
            return NULL;
        return string2;
    }
    if (string == NULL) {
        PyErr_SetString(PyExc_TypeError,
                        "Required argument 'string' (pos 1) not found");
        return NULL;
    }
    return string;
}

static PyObject*
pattern_match(PatternObject* self, PyObject* args, PyObject* kw)
{
    SRE_STATE state;
    int status;

    PyObject *string = NULL, *string2 = NULL;
    Py_ssize_t start = 0;
    Py_ssize_t end = PY_SSIZE_T_MAX;
    static char* kwlist[] = { "string", "pos", "endpos", "pattern", NULL };
    if (!check_args_size("match", args, kw, 3))
        return NULL;

    if (!PyArg_ParseTupleAndKeywords(args, kw, "|OnnO:match", kwlist,
                                     &string, &start, &end, &string2))
        return NULL;

    string = fix_string_param(string, string2, "pattern");
    if (!string)
        return NULL;

    string = state_init(&state, self, string, start, end);
    if (!string)
        return NULL;

    state.ptr = state.start;

    TRACE(("|%p|%p|MATCH\n", PatternObject_GetCode(self), state.ptr));

    if (state.charsize == 1) {
        status = sre_match(&state, PatternObject_GetCode(self));
    } else {
#if defined(HAVE_UNICODE)
        status = sre_umatch(&state, PatternObject_GetCode(self));
#endif
    }

    TRACE(("|%p|%p|END\n", PatternObject_GetCode(self), state.ptr));
    if (PyErr_Occurred())
        return NULL;

    state_fini(&state);

    return pattern_new_match(self, &state, status);
}

static PyObject*
pattern_search(PatternObject* self, PyObject* args, PyObject* kw)
{
    SRE_STATE state;
    int status;

    PyObject *string = NULL, *string2 = NULL;
    Py_ssize_t start = 0;
    Py_ssize_t end = PY_SSIZE_T_MAX;
    static char* kwlist[] = { "string", "pos", "endpos", "pattern", NULL };
    if (!check_args_size("search", args, kw, 3))
        return NULL;

    if (!PyArg_ParseTupleAndKeywords(args, kw, "|OnnO:search", kwlist,
                                     &string, &start, &end, &string2))
        return NULL;

    string = fix_string_param(string, string2, "pattern");
    if (!string)
        return NULL;

    string = state_init(&state, self, string, start, end);
    if (!string)
        return NULL;

    TRACE(("|%p|%p|SEARCH\n", PatternObject_GetCode(self), state.ptr));

    if (state.charsize == 1) {
        status = sre_search(&state, PatternObject_GetCode(self));
    } else {
#if defined(HAVE_UNICODE)
        status = sre_usearch(&state, PatternObject_GetCode(self));
#endif
    }

    TRACE(("|%p|%p|END\n", PatternObject_GetCode(self), state.ptr));

    state_fini(&state);

    if (PyErr_Occurred())
        return NULL;

    return pattern_new_match(self, &state, status);
}

static PyObject*
call(char* module, char* function, PyObject* args)
{
    PyObject* name;
    PyObject* mod;
    PyObject* func;
    PyObject* result;

    if (!args)
        return NULL;
    name = PyString_FromString(module);
    if (!name)
        return NULL;
    mod = PyImport_Import(name);
    Py_DECREF(name);
    if (!mod)
        return NULL;
    func = PyObject_GetAttrString(mod, function);
    Py_DECREF(mod);
    if (!func)
        return NULL;
    result = PyObject_CallObject(func, args);
    Py_DECREF(func);
    Py_DECREF(args);
    return result;
}

#ifdef USE_BUILTIN_COPY
static int
deepcopy(PyObject** object, PyObject* memo)
{
    PyObject* copy;

    copy = call(
        "copy", "deepcopy",
        PyTuple_Pack(2, *object, memo)
        );
    if (!copy)
        return 0;

    Py_DECREF(*object);
    *object = copy;

    return 1; /* success */
}
#endif

static PyObject*
join_list(PyObject* list, PyObject* string)
{
    /* join list elements */

    PyObject* joiner;
#if PY_VERSION_HEX >= 0x01060000
    PyObject* function;
    PyObject* args;
#endif
    PyObject* result;

    joiner = PySequence_GetSlice(string, 0, 0);
    if (!joiner)
        return NULL;

    if (PyList_GET_SIZE(list) == 0) {
        Py_DECREF(list);
        return joiner;
    }

#if PY_VERSION_HEX >= 0x01060000
    function = PyObject_GetAttrString(joiner, "join");
    if (!function) {
        Py_DECREF(joiner);
        return NULL;
    }
    args = PyTuple_New(1);
    if (!args) {
        Py_DECREF(function);
        Py_DECREF(joiner);
        return NULL;
    }
    PyTuple_SET_ITEM(args, 0, list);
    result = PyObject_CallObject(function, args);
    Py_DECREF(args); /* also removes list */
    Py_DECREF(function);
#else
    result = call(
        "string", "join",
        PyTuple_Pack(2, list, joiner)
        );
#endif
    Py_DECREF(joiner);

    return result;
}

static PyObject*
pattern_findall(PatternObject* self, PyObject* args, PyObject* kw)
{
    SRE_STATE state;
    PyObject* list;
    int status;
    Py_ssize_t i, b, e;

    PyObject *string = NULL, *string2 = NULL;
    Py_ssize_t start = 0;
    Py_ssize_t end = PY_SSIZE_T_MAX;
    static char* kwlist[] = { "string", "pos", "endpos", "source", NULL };
    if (!check_args_size("findall", args, kw, 3))
        return NULL;

    if (!PyArg_ParseTupleAndKeywords(args, kw, "|OnnO:findall", kwlist,
                                     &string, &start, &end, &string2))
        return NULL;

    string = fix_string_param(string, string2, "source");
    if (!string)
        return NULL;

    string = state_init(&state, self, string, start, end);
    if (!string)
        return NULL;

    list = PyList_New(0);
    if (!list) {
        state_fini(&state);
        return NULL;
    }

    while (state.start <= state.end) {

        PyObject* item;

        state_reset(&state);

        state.ptr = state.start;

        if (state.charsize == 1) {
            status = sre_search(&state, PatternObject_GetCode(self));
        } else {
#if defined(HAVE_UNICODE)
            status = sre_usearch(&state, PatternObject_GetCode(self));
#endif
        }

  if (PyErr_Occurred())
      goto error;

        if (status <= 0) {
            if (status == 0)
                break;
            pattern_error(status);
            goto error;
        }

        /* don't bother to build a match object */
        switch (self->groups) {
        case 0:
            b = STATE_OFFSET(&state, state.start);
            e = STATE_OFFSET(&state, state.ptr);
            item = PySequence_GetSlice(string, b, e);
            if (!item)
                goto error;
            break;
        case 1:
            item = state_getslice(&state, 1, string, 1);
            if (!item)
                goto error;
            break;
        default:
            item = PyTuple_New(self->groups);
            if (!item)
                goto error;
            for (i = 0; i < self->groups; i++) {
                PyObject* o = state_getslice(&state, i+1, string, 1);
                if (!o) {
                    Py_DECREF(item);
                    goto error;
                }
                PyTuple_SET_ITEM(item, i, o);
            }
            break;
        }

        status = PyList_Append(list, item);
        Py_DECREF(item);
        if (status < 0)
            goto error;

        if (state.ptr == state.start)
            state.start = (void*) ((char*) state.ptr + state.charsize);
        else
            state.start = state.ptr;

    }

    state_fini(&state);
    return list;

error:
    Py_DECREF(list);
    state_fini(&state);
    return NULL;

}

#if PY_VERSION_HEX >= 0x02020000
static PyObject*
pattern_finditer(PatternObject* pattern, PyObject* args)
{
    PyObject* scanner;
    PyObject* search;
    PyObject* iterator;

    scanner = pattern_scanner(pattern, args);
    if (!scanner)
        return NULL;

    search = PyObject_GetAttrString(scanner, "search");
    Py_DECREF(scanner);
    if (!search)
        return NULL;

    iterator = PyCallIter_New(search, Py_None);
    Py_DECREF(search);

    return iterator;
}
#endif

static PyObject*
pattern_split(PatternObject* self, PyObject* args, PyObject* kw)
{
    SRE_STATE state;
    PyObject* list;
    PyObject* item;
    int status;
    Py_ssize_t n;
    Py_ssize_t i;
    void* last;

    PyObject *string = NULL, *string2 = NULL;
    Py_ssize_t maxsplit = 0;
    static char* kwlist[] = { "string", "maxsplit", "source", NULL };
    if (!check_args_size("split", args, kw, 2))
        return NULL;

    if (!PyArg_ParseTupleAndKeywords(args, kw, "|OnO:split", kwlist,
                                     &string, &maxsplit, &string2))
        return NULL;

    string = fix_string_param(string, string2, "source");
    if (!string)
        return NULL;

    string = state_init(&state, self, string, 0, PY_SSIZE_T_MAX);
    if (!string)
        return NULL;

    list = PyList_New(0);
    if (!list) {
        state_fini(&state);
        return NULL;
    }

    n = 0;
    last = state.start;

    while (!maxsplit || n < maxsplit) {

        state_reset(&state);

        state.ptr = state.start;

        if (state.charsize == 1) {
            status = sre_search(&state, PatternObject_GetCode(self));
        } else {
#if defined(HAVE_UNICODE)
            status = sre_usearch(&state, PatternObject_GetCode(self));
#endif
        }

  if (PyErr_Occurred())
      goto error;

        if (status <= 0) {
            if (status == 0)
                break;
            pattern_error(status);
            goto error;
        }

        if (state.start == state.ptr) {
            if (last == state.end)
                break;
            /* skip one character */
            state.start = (void*) ((char*) state.ptr + state.charsize);
            continue;
        }

        /* get segment before this match */
        item = PySequence_GetSlice(
            string, STATE_OFFSET(&state, last),
            STATE_OFFSET(&state, state.start)
            );
        if (!item)
            goto error;
        status = PyList_Append(list, item);
        Py_DECREF(item);
        if (status < 0)
            goto error;

        /* add groups (if any) */
        for (i = 0; i < self->groups; i++) {
            item = state_getslice(&state, i+1, string, 0);
            if (!item)
                goto error;
            status = PyList_Append(list, item);
            Py_DECREF(item);
            if (status < 0)
                goto error;
        }

        n = n + 1;

        last = state.start = state.ptr;

    }

    /* get segment following last match (even if empty) */
    item = PySequence_GetSlice(
        string, STATE_OFFSET(&state, last), state.endpos
        );
    if (!item)
        goto error;
    status = PyList_Append(list, item);
    Py_DECREF(item);
    if (status < 0)
        goto error;

    state_fini(&state);
    return list;

error:
    Py_DECREF(list);
    state_fini(&state);
    return NULL;

}

static PyObject*
pattern_subx(PatternObject* self, PyObject* ptemplate, PyObject* string,
             Py_ssize_t count, Py_ssize_t subn)
{
    SRE_STATE state;
    PyObject* list;
    PyObject* item;
    PyObject* filter;
    PyObject* args;
    PyObject* match;
    void* ptr;
    int status;
    Py_ssize_t n;
    Py_ssize_t i, b, e;
    int bint;
    int filter_is_callable;

    if (PyCallable_Check(ptemplate)) {
        /* sub/subn takes either a function or a template */
        filter = ptemplate;
        Py_INCREF(filter);
        filter_is_callable = 1;
    } else {
        /* if not callable, check if it's a literal string */
        int literal;
        ptr = getstring(ptemplate, &n, &bint);
        b = bint;
        if (ptr) {
            if (b == 1) {
        literal = sre_literal_template((unsigned char *)ptr, n);
            } else {
#if defined(HAVE_UNICODE)
        literal = sre_uliteral_template((Py_UNICODE *)ptr, n);
#endif
            }
        } else {
            PyErr_Clear();
            literal = 0;
        }
        if (literal) {
            filter = ptemplate;
            Py_INCREF(filter);
            filter_is_callable = 0;
        } else {
            /* not a literal; hand it over to the template compiler */
            filter = call(
                SRE_PY_MODULE, "_subx",
                PyTuple_Pack(2, self, ptemplate)
                );
            if (!filter)
                return NULL;
            filter_is_callable = PyCallable_Check(filter);
        }
    }

    string = state_init(&state, self, string, 0, PY_SSIZE_T_MAX);
    if (!string) {
        Py_DECREF(filter);
        return NULL;
    }

    list = PyList_New(0);
    if (!list) {
        Py_DECREF(filter);
        state_fini(&state);
        return NULL;
    }

    n = i = 0;

    while (!count || n < count) {

        state_reset(&state);

        state.ptr = state.start;

        if (state.charsize == 1) {
            status = sre_search(&state, PatternObject_GetCode(self));
        } else {
#if defined(HAVE_UNICODE)
            status = sre_usearch(&state, PatternObject_GetCode(self));
#endif
        }

  if (PyErr_Occurred())
      goto error;

        if (status <= 0) {
            if (status == 0)
                break;
            pattern_error(status);
            goto error;
        }

        b = STATE_OFFSET(&state, state.start);
        e = STATE_OFFSET(&state, state.ptr);

        if (i < b) {
            /* get segment before this match */
            item = PySequence_GetSlice(string, i, b);
            if (!item)
                goto error;
            status = PyList_Append(list, item);
            Py_DECREF(item);
            if (status < 0)
                goto error;

        } else if (i == b && i == e && n > 0)
            /* ignore empty match on latest position */
            goto next;

        if (filter_is_callable) {
            /* pass match object through filter */
            match = pattern_new_match(self, &state, 1);
            if (!match)
                goto error;
            args = PyTuple_Pack(1, match);
            if (!args) {
                Py_DECREF(match);
                goto error;
            }
            item = PyObject_CallObject(filter, args);
            Py_DECREF(args);
            Py_DECREF(match);
            if (!item)
                goto error;
        } else {
            /* filter is literal string */
            item = filter;
            Py_INCREF(item);
        }

        /* add to list */
        if (item != Py_None) {
            status = PyList_Append(list, item);
            Py_DECREF(item);
            if (status < 0)
                goto error;
        }

        i = e;
        n = n + 1;

next:
        /* move on */
        if (state.ptr == state.start)
            state.start = (void*) ((char*) state.ptr + state.charsize);
        else
            state.start = state.ptr;

    }

    /* get segment following last match */
    if (i < state.endpos) {
        item = PySequence_GetSlice(string, i, state.endpos);
        if (!item)
            goto error;
        status = PyList_Append(list, item);
        Py_DECREF(item);
        if (status < 0)
            goto error;
    }

    state_fini(&state);

    Py_DECREF(filter);

    /* convert list to single string (also removes list) */
    item = join_list(list, string);

    if (!item)
        return NULL;

    if (subn)
        return Py_BuildValue("Nn", item, n);

    return item;

error:
    Py_DECREF(list);
    state_fini(&state);
    Py_DECREF(filter);
    return NULL;

}

static PyObject*
pattern_sub(PatternObject* self, PyObject* args, PyObject* kw)
{
    PyObject* ptemplate;
    PyObject* string;
    Py_ssize_t count = 0;
    static char* kwlist[] = { "repl", "string", "count", NULL };
    if (!PyArg_ParseTupleAndKeywords(args, kw, "OO|n:sub", kwlist,
                                     &ptemplate, &string, &count))
        return NULL;

    return pattern_subx(self, ptemplate, string, count, 0);
}

static PyObject*
pattern_subn(PatternObject* self, PyObject* args, PyObject* kw)
{
    PyObject* ptemplate;
    PyObject* string;
    Py_ssize_t count = 0;
    static char* kwlist[] = { "repl", "string", "count", NULL };
    if (!PyArg_ParseTupleAndKeywords(args, kw, "OO|n:subn", kwlist,
                                     &ptemplate, &string, &count))
        return NULL;

    return pattern_subx(self, ptemplate, string, count, 1);
}

static PyObject*
pattern_copy(PatternObject* self, PyObject *unused)
{
#ifdef USE_BUILTIN_COPY
    PatternObject* copy;
    int offset;

    copy = PyObject_NEW_VAR(PatternObject, &Pattern_Type, self->codesize);
    if (!copy)
        return NULL;

    offset = offsetof(PatternObject, groups);

    Py_XINCREF(self->groupindex);
    Py_XINCREF(self->indexgroup);
    Py_XINCREF(self->pattern);

    memcpy((char*) copy + offset, (char*) self + offset,
           sizeof(PatternObject) + self->codesize * sizeof(SRE_CODE) - offset);
    copy->weakreflist = NULL;

    return (PyObject*) copy;
#else
    PyErr_SetString(PyExc_TypeError, "cannot copy this pattern object");
    return NULL;
#endif
}

static PyObject*
pattern_deepcopy(PatternObject* self, PyObject* memo)
{
#ifdef USE_BUILTIN_COPY
    PatternObject* copy;

    copy = (PatternObject*) pattern_copy(self);
    if (!copy)
        return NULL;

    if (!deepcopy(&copy->groupindex, memo) ||
        !deepcopy(&copy->indexgroup, memo) ||
        !deepcopy(&copy->pattern, memo)) {
        Py_DECREF(copy);
        return NULL;
    }

#else
    PyErr_SetString(PyExc_TypeError, "cannot deepcopy this pattern object");
    return NULL;
#endif
}

PyDoc_STRVAR(pattern_match_doc,
"match(string[, pos[, endpos]]) --> match object or None.\n\
    Matches zero or more characters at the beginning of the string");

PyDoc_STRVAR(pattern_search_doc,
"search(string[, pos[, endpos]]) --> match object or None.\n\
    Scan through string looking for a match, and return a corresponding\n\
    match object instance. Return None if no position in the string matches.");

PyDoc_STRVAR(pattern_split_doc,
"split(string[, maxsplit = 0])  --> list.\n\
    Split string by the occurrences of pattern.");

PyDoc_STRVAR(pattern_findall_doc,
"findall(string[, pos[, endpos]]) --> list.\n\
   Return a list of all non-overlapping matches of pattern in string.");

PyDoc_STRVAR(pattern_finditer_doc,
"finditer(string[, pos[, endpos]]) --> iterator.\n\
    Return an iterator over all non-overlapping matches for the \n\
    RE pattern in string. For each match, the iterator returns a\n\
    match object.");

PyDoc_STRVAR(pattern_sub_doc,
"sub(repl, string[, count = 0]) --> newstring\n\
    Return the string obtained by replacing the leftmost non-overlapping\n\
    occurrences of pattern in string by the replacement repl.");

PyDoc_STRVAR(pattern_subn_doc,
"subn(repl, string[, count = 0]) --> (newstring, number of subs)\n\
    Return the tuple (new_string, number_of_subs_made) found by replacing\n\
    the leftmost non-overlapping occurrences of pattern with the\n\
    replacement repl.");

PyDoc_STRVAR(pattern_doc, "Compiled regular expression objects");

static PyMethodDef pattern_methods[] = {
    {"match", (PyCFunction) pattern_match, METH_VARARGS|METH_KEYWORDS,
  pattern_match_doc},
    {"search", (PyCFunction) pattern_search, METH_VARARGS|METH_KEYWORDS,
  pattern_search_doc},
    {"sub", (PyCFunction) pattern_sub, METH_VARARGS|METH_KEYWORDS,
  pattern_sub_doc},
    {"subn", (PyCFunction) pattern_subn, METH_VARARGS|METH_KEYWORDS,
  pattern_subn_doc},
    {"split", (PyCFunction) pattern_split, METH_VARARGS|METH_KEYWORDS,
  pattern_split_doc},
    {"findall", (PyCFunction) pattern_findall, METH_VARARGS|METH_KEYWORDS,
  pattern_findall_doc},
#if PY_VERSION_HEX >= 0x02020000
    {"finditer", (PyCFunction) pattern_finditer, METH_VARARGS,
  pattern_finditer_doc},
#endif
    {"scanner", (PyCFunction) pattern_scanner, METH_VARARGS},
    {"__copy__", (PyCFunction) pattern_copy, METH_NOARGS},
    {"__deepcopy__", (PyCFunction) pattern_deepcopy, METH_O},
    {NULL, NULL}
};

#define PAT_OFF(x) offsetof(PatternObject, x)
static PyMemberDef pattern_members[] = {
    {"pattern",    T_OBJECT,    PAT_OFF(pattern),       READONLY},
    {"flags",      T_INT,       PAT_OFF(flags),         READONLY},
    {"groups",     T_PYSSIZET,  PAT_OFF(groups),        READONLY},
    {"groupindex", T_OBJECT,    PAT_OFF(groupindex),    READONLY},
    {NULL}  /* Sentinel */
};

statichere PyTypeObject Pattern_Type = {
    PyObject_HEAD_INIT(NULL)
    0, "_" SRE_MODULE ".SRE_Pattern",
    sizeof(PatternObject), sizeof(SRE_CODE),
    (destructor)pattern_dealloc, /*tp_dealloc*/
    0,                                  /* tp_print */
    0,                                  /* tp_getattrn */
    0,          /* tp_setattr */
    0,          /* tp_compare */
    0,          /* tp_repr */
    0,          /* tp_as_number */
    0,          /* tp_as_sequence */
    0,          /* tp_as_mapping */
    0,          /* tp_hash */
    0,          /* tp_call */
    0,          /* tp_str */
    0,          /* tp_getattro */
    0,          /* tp_setattro */
    0,          /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT,           /* tp_flags */
    pattern_doc,      /* tp_doc */
    0,          /* tp_traverse */
    0,          /* tp_clear */
    0,          /* tp_richcompare */
    offsetof(PatternObject, weakreflist), /* tp_weaklistoffset */
    0,          /* tp_iter */
    0,          /* tp_iternext */
    pattern_methods,      /* tp_methods */
    pattern_members,      /* tp_members */
};

static int _validate(PatternObject *self); /* Forward */

static PyObject *
_compile(PyObject* self_, PyObject* args)
{
    /* "compile" pattern descriptor to pattern object */

    PatternObject* self;
    Py_ssize_t i, n;

    PyObject* pattern;
    int flags = 0;
    PyObject* code;
    Py_ssize_t groups = 0;
    PyObject* groupindex = NULL;
    PyObject* indexgroup = NULL;
    if (!PyArg_ParseTuple(args, "OiO!|nOO", &pattern, &flags,
                          &PyList_Type, &code, &groups,
                          &groupindex, &indexgroup))
        return NULL;

    n = PyList_GET_SIZE(code);
    /* coverity[ampersand_in_size] */
    self = PyObject_NEW_VAR(PatternObject, &Pattern_Type, n);
    if (!self)
        return NULL;
    self->weakreflist = NULL;
    self->pattern = NULL;
    self->groupindex = NULL;
    self->indexgroup = NULL;

    self->codesize = n;

    for (i = 0; i < n; i++) {
        PyObject *o = PyList_GET_ITEM(code, i);
        unsigned long value = PyInt_Check(o) ? (unsigned long)PyInt_AsLong(o)
                                              : PyLong_AsUnsignedLong(o);
        if (value == (unsigned long)-1 && PyErr_Occurred()) {
            if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
                PyErr_SetString(PyExc_OverflowError,
                                "regular expression code size limit exceeded");
            }
            break;
        }
        self->code[i] = (SRE_CODE) value;
        if ((unsigned long) self->code[i] != value) {
            PyErr_SetString(PyExc_OverflowError,
                            "regular expression code size limit exceeded");
            break;
        }
    }

    if (PyErr_Occurred()) {
        Py_DECREF(self);
        return NULL;
    }

    Py_INCREF(pattern);
    self->pattern = pattern;

    self->flags = flags;

    self->groups = groups;

    Py_XINCREF(groupindex);
    self->groupindex = groupindex;

    Py_XINCREF(indexgroup);
    self->indexgroup = indexgroup;

    self->weakreflist = NULL;

    if (!_validate(self)) {
        Py_DECREF(self);
        return NULL;
    }

    return (PyObject*) self;
}

/* -------------------------------------------------------------------- */
/* Code validation */

/* To learn more about this code, have a look at the _compile() function in
   Lib/sre_compile.py.  The validation functions below checks the code array
   for conformance with the code patterns generated there.

   The nice thing about the generated code is that it is position-independent:
   all jumps are relative jumps forward.  Also, jumps don't cross each other:
   the target of a later jump is always earlier than the target of an earlier
   jump.  IOW, this is okay:

   J---------J-------T--------T
    \         \_____/        /
     \______________________/

   but this is not:

   J---------J-------T--------T
    \_________\_____/        /
               \____________/

   It also helps that SRE_CODE is always an unsigned type.
*/

/* Defining this one enables tracing of the validator */
#undef VVERBOSE

/* Trace macro for the validator */
#if defined(VVERBOSE)
#define VTRACE(v) printf v
#else
#define VTRACE(v) do {} while(0)  /* do nothing */
#endif

/* Report failure */
#define FAIL do { VTRACE(("FAIL: %d\n", __LINE__)); return 0; } while (0)

/* Extract opcode, argument, or skip count from code array */
#define GET_OP                                          \
    do {                                                \
        VTRACE(("%p: ", code));                         \
        if (code >= end) FAIL;                          \
        op = *code++;                                   \
        VTRACE(("%lu (op)\n", (unsigned long)op));      \
    } while (0)
#define GET_ARG                                         \
    do {                                                \
        VTRACE(("%p= ", code));                         \
        if (code >= end) FAIL;                          \
        arg = *code++;                                  \
        VTRACE(("%lu (arg)\n", (unsigned long)arg));    \
    } while (0)
#define GET_SKIP_ADJ(adj)                               \
    do {                                                \
        VTRACE(("%p= ", code));                         \
        if (code >= end) FAIL;                          \
        skip = *code;                                   \
        VTRACE(("%lu (skip to %p)\n",                   \
               (unsigned long)skip, code+skip));        \
        if (skip-adj > end-code)                        \
            FAIL;                                       \
        code++;                                         \
    } while (0)
#define GET_SKIP GET_SKIP_ADJ(0)

static int
_validate_charset(SRE_CODE *code, SRE_CODE *end)
{
    /* Some variables are manipulated by the macros above */
    SRE_CODE op;
    SRE_CODE arg;
    SRE_CODE offset;
    int i;

    while (code < end) {
        GET_OP;
        switch (op) {

        case SRE_OP_NEGATE:
            break;

        case SRE_OP_LITERAL:
            GET_ARG;
            break;

        case SRE_OP_RANGE:
            GET_ARG;
            GET_ARG;
            break;

        case SRE_OP_CHARSET:
            offset = 32/sizeof(SRE_CODE); /* 32-byte bitmap */
            if (offset > end-code)
                FAIL;
            code += offset;
            break;

        case SRE_OP_BIGCHARSET:
            GET_ARG; /* Number of blocks */
            offset = 256/sizeof(SRE_CODE); /* 256-byte table */
            if (offset > end-code)
                FAIL;
            /* Make sure that each byte points to a valid block */
            for (i = 0; i < 256; i++) {
                if (((unsigned char *)code)[i] >= arg)
                    FAIL;
            }
            code += offset;
            offset = arg * 32/sizeof(SRE_CODE); /* 32-byte bitmap times arg */
            if (offset > end-code)
                FAIL;
            code += offset;
            break;

        case SRE_OP_CATEGORY:
            GET_ARG;
            switch (arg) {
            case SRE_CATEGORY_DIGIT:
            case SRE_CATEGORY_NOT_DIGIT:
            case SRE_CATEGORY_SPACE:
            case SRE_CATEGORY_NOT_SPACE:
            case SRE_CATEGORY_WORD:
            case SRE_CATEGORY_NOT_WORD:
            case SRE_CATEGORY_LINEBREAK:
            case SRE_CATEGORY_NOT_LINEBREAK:
            case SRE_CATEGORY_LOC_WORD:
            case SRE_CATEGORY_LOC_NOT_WORD:
            case SRE_CATEGORY_UNI_DIGIT:
            case SRE_CATEGORY_UNI_NOT_DIGIT:
            case SRE_CATEGORY_UNI_SPACE:
            case SRE_CATEGORY_UNI_NOT_SPACE:
            case SRE_CATEGORY_UNI_WORD:
            case SRE_CATEGORY_UNI_NOT_WORD:
            case SRE_CATEGORY_UNI_LINEBREAK:
            case SRE_CATEGORY_UNI_NOT_LINEBREAK:
                break;
            default:
                FAIL;
            }
            break;

        default:
            FAIL;

        }
    }

    return 1;
}

static int
_validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups)
{
    /* Some variables are manipulated by the macros above */
    SRE_CODE op;
    SRE_CODE arg;
    SRE_CODE skip;

    VTRACE(("code=%p, end=%p\n", code, end));

    if (code > end)
        FAIL;

    while (code < end) {
        GET_OP;
        switch (op) {

        case SRE_OP_MARK:
            /* We don't check whether marks are properly nested; the
               sre_match() code is robust even if they don't, and the worst
               you can get is nonsensical match results. */
            GET_ARG;
            if (arg > 2*groups+1) {
                VTRACE(("arg=%d, groups=%d\n", (int)arg, (int)groups));
                FAIL;
            }
            break;

        case SRE_OP_LITERAL:
        case SRE_OP_NOT_LITERAL:
        case SRE_OP_LITERAL_IGNORE:
        case SRE_OP_NOT_LITERAL_IGNORE:
            GET_ARG;
            /* The arg is just a character, nothing to check */
            break;

        case SRE_OP_SUCCESS:
        case SRE_OP_FAILURE:
            /* Nothing to check; these normally end the matching process */
            break;

        case SRE_OP_AT:
            GET_ARG;
            switch (arg) {
            case SRE_AT_BEGINNING:
            case SRE_AT_BEGINNING_STRING:
            case SRE_AT_BEGINNING_LINE:
            case SRE_AT_END:
            case SRE_AT_END_LINE:
            case SRE_AT_END_STRING:
            case SRE_AT_BOUNDARY:
            case SRE_AT_NON_BOUNDARY:
            case SRE_AT_LOC_BOUNDARY:
            case SRE_AT_LOC_NON_BOUNDARY:
            case SRE_AT_UNI_BOUNDARY:
            case SRE_AT_UNI_NON_BOUNDARY:
                break;
            default:
                FAIL;
            }
            break;

        case SRE_OP_ANY:
        case SRE_OP_ANY_ALL:
            /* These have no operands */
            break;

        case SRE_OP_IN:
        case SRE_OP_IN_IGNORE:
            GET_SKIP;
            /* Stop 1 before the end; we check the FAILURE below */
            if (!_validate_charset(code, code+skip-2))
                FAIL;
            if (code[skip-2] != SRE_OP_FAILURE)
                FAIL;
            code += skip-1;
            break;

        case SRE_OP_INFO:
            {
                /* A minimal info field is
                   <INFO> <1=skip> <2=flags> <3=min> <4=max>;
                   If SRE_INFO_PREFIX or SRE_INFO_CHARSET is in the flags,
                   more follows. */
                SRE_CODE flags, i;
                SRE_CODE *newcode;
                GET_SKIP;
                newcode = code+skip-1;
                GET_ARG; flags = arg;
                GET_ARG; /* min */
                GET_ARG; /* max */
                /* Check that only valid flags are present */
                if ((flags & ~(SRE_INFO_PREFIX |
                               SRE_INFO_LITERAL |
                               SRE_INFO_CHARSET)) != 0)
                    FAIL;
                /* PREFIX and CHARSET are mutually exclusive */
                if ((flags & SRE_INFO_PREFIX) &&
                    (flags & SRE_INFO_CHARSET))
                    FAIL;
                /* LITERAL implies PREFIX */
                if ((flags & SRE_INFO_LITERAL) &&
                    !(flags & SRE_INFO_PREFIX))
                    FAIL;
                /* Validate the prefix */
                if (flags & SRE_INFO_PREFIX) {
                    SRE_CODE prefix_len;
                    GET_ARG; prefix_len = arg;
                    GET_ARG; /* prefix skip */
                    /* Here comes the prefix string */
                    if (prefix_len > newcode-code)
                        FAIL;
                    code += prefix_len;
                    /* And here comes the overlap table */
                    if (prefix_len > newcode-code)
                        FAIL;
                    /* Each overlap value should be < prefix_len */
                    for (i = 0; i < prefix_len; i++) {
                        if (code[i] >= prefix_len)
                            FAIL;
                    }
                    code += prefix_len;
                }
                /* Validate the charset */
                if (flags & SRE_INFO_CHARSET) {
                    if (!_validate_charset(code, newcode-1))
                        FAIL;
                    if (newcode[-1] != SRE_OP_FAILURE)
                        FAIL;
                    code = newcode;
                }
                else if (code != newcode) {
                  VTRACE(("code=%p, newcode=%p\n", code, newcode));
                    FAIL;
                }
            }
            break;

        case SRE_OP_BRANCH:
            {
                SRE_CODE *target = NULL;
                for (;;) {
                    GET_SKIP;
                    if (skip == 0)
                        break;
                    /* Stop 2 before the end; we check the JUMP below */
                    if (!_validate_inner(code, code+skip-3, groups))
                        FAIL;
                    code += skip-3;
                    /* Check that it ends with a JUMP, and that each JUMP
                       has the same target */
                    GET_OP;
                    if (op != SRE_OP_JUMP)
                        FAIL;
                    GET_SKIP;
                    if (target == NULL)
                        target = code+skip-1;
                    else if (code+skip-1 != target)
                        FAIL;
                }
            }
            break;

        case SRE_OP_REPEAT_ONE:
        case SRE_OP_MIN_REPEAT_ONE:
            {
                SRE_CODE min, max;
                GET_SKIP;
                GET_ARG; min = arg;
                GET_ARG; max = arg;
                if (min > max)
                    FAIL;
                if (max > SRE_MAXREPEAT)
                    FAIL;
                if (!_validate_inner(code, code+skip-4, groups))
                    FAIL;
                code += skip-4;
                GET_OP;
                if (op != SRE_OP_SUCCESS)
                    FAIL;
            }
            break;

        case SRE_OP_REPEAT:
            {
                SRE_CODE min, max;
                GET_SKIP;
                GET_ARG; min = arg;
                GET_ARG; max = arg;
                if (min > max)
                    FAIL;
                if (max > SRE_MAXREPEAT)
                    FAIL;
                if (!_validate_inner(code, code+skip-3, groups))
                    FAIL;
                code += skip-3;
                GET_OP;
                if (op != SRE_OP_MAX_UNTIL && op != SRE_OP_MIN_UNTIL)
                    FAIL;
            }
            break;

        case SRE_OP_GROUPREF:
        case SRE_OP_GROUPREF_IGNORE:
            GET_ARG;
            if (arg >= groups)
                FAIL;
            break;

        case SRE_OP_GROUPREF_EXISTS:
            /* The regex syntax for this is: '(?(group)then|else)', where
               'group' is either an integer group number or a group name,
               'then' and 'else' are sub-regexes, and 'else' is optional. */
            GET_ARG;
            if (arg >= groups)
                FAIL;
            GET_SKIP_ADJ(1);
            code--; /* The skip is relative to the first arg! */
            /* There are two possibilities here: if there is both a 'then'
               part and an 'else' part, the generated code looks like:

               GROUPREF_EXISTS
               <group>
               <skipyes>
               ...then part...
               JUMP
               <skipno>
               (<skipyes> jumps here)
               ...else part...
               (<skipno> jumps here)

               If there is only a 'then' part, it looks like:

               GROUPREF_EXISTS
               <group>
               <skip>
               ...then part...
               (<skip> jumps here)

               There is no direct way to decide which it is, and we don't want
               to allow arbitrary jumps anywhere in the code; so we just look
               for a JUMP opcode preceding our skip target.
            */
            if (skip >= 3 && skip-3 < end-code &&
                code[skip-3] == SRE_OP_JUMP)
            {
                VTRACE(("both then and else parts present\n"));
                if (!_validate_inner(code+1, code+skip-3, groups))
                    FAIL;
                code += skip-2; /* Position after JUMP, at <skipno> */
                GET_SKIP;
                if (!_validate_inner(code, code+skip-1, groups))
                    FAIL;
                code += skip-1;
            }
            else {
                VTRACE(("only a then part present\n"));
                if (!_validate_inner(code+1, code+skip-1, groups))
                    FAIL;
                code += skip-1;
            }
            break;

        case SRE_OP_ASSERT:
        case SRE_OP_ASSERT_NOT:
            GET_SKIP;
            GET_ARG; /* 0 for lookahead, width for lookbehind */
            code--; /* Back up over arg to simplify math below */
            if (arg & 0x80000000)
                FAIL; /* Width too large */
            /* Stop 1 before the end; we check the SUCCESS below */
            if (!_validate_inner(code+1, code+skip-2, groups))
                FAIL;
            code += skip-2;
            GET_OP;
            if (op != SRE_OP_SUCCESS)
                FAIL;
            break;

        default:
            FAIL;

        }
    }

    VTRACE(("okay\n"));
    return 1;
}

static int
_validate_outer(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups)
{
    if (groups < 0 || groups > 100 || code >= end || end[-1] != SRE_OP_SUCCESS)
        FAIL;
    if (groups == 0)  /* fix for simplejson */
        groups = 100; /* 100 groups should always be safe */
    return _validate_inner(code, end-1, groups);
}

static int
_validate(PatternObject *self)
{
    if (!_validate_outer(self->code, self->code+self->codesize, self->groups))
    {
        PyErr_SetString(PyExc_RuntimeError, "invalid SRE code");
        return 0;
    }
    else
        VTRACE(("Success!\n"));
    return 1;
}

/* -------------------------------------------------------------------- */
/* match methods */

static void
match_dealloc(MatchObject* self)
{
    Py_XDECREF(self->regs);
    Py_XDECREF(self->string);
    Py_DECREF(self->pattern);
    PyObject_DEL(self);
}

static PyObject*
match_getslice_by_index(MatchObject* self, Py_ssize_t index, PyObject* def)
{
    if (index < 0 || index >= self->groups) {
        /* raise IndexError if we were given a bad group number */
        PyErr_SetString(
            PyExc_IndexError,
            "no such group"
            );
        return NULL;
    }

    index *= 2;

    if (self->string == Py_None || self->mark[index] < 0) {
        /* return default value if the string or group is undefined */
        Py_INCREF(def);
        return def;
    }

    return PySequence_GetSlice(
        self->string, self->mark[index], self->mark[index+1]
        );
}

static Py_ssize_t
match_getindex(MatchObject* self, PyObject* index)
{
    Py_ssize_t i;

    if (PyInt_Check(index) || PyLong_Check(index))
        return PyInt_AsSsize_t(index);

    i = -1;

    if (self->pattern->groupindex) {
        index = PyObject_GetItem(self->pattern->groupindex, index);
        if (index) {
            if (PyInt_Check(index) || PyLong_Check(index))
                i = PyInt_AsSsize_t(index);
            Py_DECREF(index);
        } else
            PyErr_Clear();
    }

    return i;
}

static PyObject*
match_getslice(MatchObject* self, PyObject* index, PyObject* def)
{
    return match_getslice_by_index(self, match_getindex(self, index), def);
}

static PyObject*
match_expand(MatchObject* self, PyObject* ptemplate)
{
    /* delegate to Python code */
    return call(
        SRE_PY_MODULE, "_expand",
        PyTuple_Pack(3, self->pattern, self, ptemplate)
        );
}

static PyObject*
match_group(MatchObject* self, PyObject* args)
{
    PyObject* result;
    Py_ssize_t i, size;

    size = PyTuple_GET_SIZE(args);

    switch (size) {
    case 0:
        result = match_getslice(self, Py_False, Py_None);
        break;
    case 1:
        result = match_getslice(self, PyTuple_GET_ITEM(args, 0), Py_None);
        break;
    default:
        /* fetch multiple items */
        result = PyTuple_New(size);
        if (!result)
            return NULL;
        for (i = 0; i < size; i++) {
            PyObject* item = match_getslice(
                self, PyTuple_GET_ITEM(args, i), Py_None
                );
            if (!item) {
                Py_DECREF(result);
                return NULL;
            }
            PyTuple_SET_ITEM(result, i, item);
        }
        break;
    }
    return result;
}

static PyObject*
match_groups(MatchObject* self, PyObject* args, PyObject* kw)
{
    PyObject* result;
    Py_ssize_t index;

    PyObject* def = Py_None;
    static char* kwlist[] = { "default", NULL };
    if (!PyArg_ParseTupleAndKeywords(args, kw, "|O:groups", kwlist, &def))
        return NULL;

    result = PyTuple_New(self->groups-1);
    if (!result)
        return NULL;

    for (index = 1; index < self->groups; index++) {
        PyObject* item;
        item = match_getslice_by_index(self, index, def);
        if (!item) {
            Py_DECREF(result);
            return NULL;
        }
        PyTuple_SET_ITEM(result, index-1, item);
    }

    return result;
}

static PyObject*
match_groupdict(MatchObject* self, PyObject* args, PyObject* kw)
{
    PyObject* result;
    PyObject* keys;
    Py_ssize_t index;

    PyObject* def = Py_None;
    static char* kwlist[] = { "default", NULL };
    if (!PyArg_ParseTupleAndKeywords(args, kw, "|O:groupdict", kwlist, &def))
        return NULL;

    result = PyDict_New();
    if (!result || !self->pattern->groupindex)
        return result;

    keys = PyMapping_Keys(self->pattern->groupindex);
    if (!keys)
        goto failed;

    for (index = 0; index < PyList_GET_SIZE(keys); index++) {
        int status;
        PyObject* key;
        PyObject* value;
        key = PyList_GET_ITEM(keys, index);
        if (!key)
            goto failed;
        value = match_getslice(self, key, def);
        if (!value) {
            Py_DECREF(key);
            goto failed;
        }
        status = PyDict_SetItem(result, key, value);
        Py_DECREF(value);
        if (status < 0)
            goto failed;
    }

    Py_DECREF(keys);

    return result;

failed:
    Py_XDECREF(keys);
    Py_DECREF(result);
    return NULL;
}

static PyObject*
match_start(MatchObject* self, PyObject* args)
{
    Py_ssize_t index;

    PyObject* index_ = Py_False; /* zero */
    if (!PyArg_UnpackTuple(args, "start", 0, 1, &index_))
        return NULL;

    index = match_getindex(self, index_);

    if (index < 0 || index >= self->groups) {
        PyErr_SetString(
            PyExc_IndexError,
            "no such group"
            );
        return NULL;
    }

    /* mark is -1 if group is undefined */
    return PyInt_FromSsize_t(self->mark[index*2]);
}

static PyObject*
match_end(MatchObject* self, PyObject* args)
{
    Py_ssize_t index;

    PyObject* index_ = Py_False; /* zero */
    if (!PyArg_UnpackTuple(args, "end", 0, 1, &index_))
        return NULL;

    index = match_getindex(self, index_);

    if (index < 0 || index >= self->groups) {
        PyErr_SetString(
            PyExc_IndexError,
            "no such group"
            );
        return NULL;
    }

    /* mark is -1 if group is undefined */
    return PyInt_FromSsize_t(self->mark[index*2+1]);
}

LOCAL(PyObject*)
_pair(Py_ssize_t i1, Py_ssize_t i2)
{
    PyObject* pair;
    PyObject* item;

    pair = PyTuple_New(2);
    if (!pair)
        return NULL;

    item = PyInt_FromSsize_t(i1);
    if (!item)
        goto error;
    PyTuple_SET_ITEM(pair, 0, item);

    item = PyInt_FromSsize_t(i2);
    if (!item)
        goto error;
    PyTuple_SET_ITEM(pair, 1, item);

    return pair;

  error:
    Py_DECREF(pair);
    return NULL;
}

static PyObject*
match_span(MatchObject* self, PyObject* args)
{
    Py_ssize_t index;

    PyObject* index_ = Py_False; /* zero */
    if (!PyArg_UnpackTuple(args, "span", 0, 1, &index_))
        return NULL;

    index = match_getindex(self, index_);

    if (index < 0 || index >= self->groups) {
        PyErr_SetString(
            PyExc_IndexError,
            "no such group"
            );
        return NULL;
    }

    /* marks are -1 if group is undefined */
    return _pair(self->mark[index*2], self->mark[index*2+1]);
}

static PyObject*
match_regs(MatchObject* self)
{
    PyObject* regs;
    PyObject* item;
    Py_ssize_t index;

    regs = PyTuple_New(self->groups);
    if (!regs)
        return NULL;

    for (index = 0; index < self->groups; index++) {
        item = _pair(self->mark[index*2], self->mark[index*2+1]);
        if (!item) {
            Py_DECREF(regs);
            return NULL;
        }
        PyTuple_SET_ITEM(regs, index, item);
    }

    Py_INCREF(regs);
    self->regs = regs;

    return regs;
}

static PyObject*
match_copy(MatchObject* self, PyObject *unused)
{
#ifdef USE_BUILTIN_COPY
    MatchObject* copy;
    Py_ssize_t slots, offset;

    slots = 2 * (self->pattern->groups+1);

    copy = PyObject_NEW_VAR(MatchObject, &Match_Type, slots);
    if (!copy)
        return NULL;

    /* this value a constant, but any compiler should be able to
       figure that out all by itself */
    offset = offsetof(MatchObject, string);

    Py_XINCREF(self->pattern);
    Py_XINCREF(self->string);
    Py_XINCREF(self->regs);

    memcpy((char*) copy + offset, (char*) self + offset,
           sizeof(MatchObject) + slots * sizeof(Py_ssize_t) - offset);

    return (PyObject*) copy;
#else
    PyErr_SetString(PyExc_TypeError, "cannot copy this match object");
    return NULL;
#endif
}

static PyObject*
match_deepcopy(MatchObject* self, PyObject* memo)
{
#ifdef USE_BUILTIN_COPY
    MatchObject* copy;

    copy = (MatchObject*) match_copy(self);
    if (!copy)
        return NULL;

    if (!deepcopy((PyObject**) &copy->pattern, memo) ||
        !deepcopy(&copy->string, memo) ||
        !deepcopy(&copy->regs, memo)) {
        Py_DECREF(copy);
        return NULL;
    }

#else
    PyErr_SetString(PyExc_TypeError, "cannot deepcopy this match object");
    return NULL;
#endif
}

PyDoc_STRVAR(match_doc,
"The result of re.match() and re.search().\n\
Match objects always have a boolean value of True.");

PyDoc_STRVAR(match_group_doc,
"group([group1, ...]) -> str or tuple.\n\
    Return subgroup(s) of the match by indices or names.\n\
    For 0 returns the entire match.");

PyDoc_STRVAR(match_start_doc,
"start([group=0]) -> int.\n\
    Return index of the start of the substring matched by group.");

PyDoc_STRVAR(match_end_doc,
"end([group=0]) -> int.\n\
    Return index of the end of the substring matched by group.");

PyDoc_STRVAR(match_span_doc,
"span([group]) -> tuple.\n\
    For MatchObject m, return the 2-tuple (m.start(group), m.end(group)).");

PyDoc_STRVAR(match_groups_doc,
"groups([default=None]) -> tuple.\n\
    Return a tuple containing all the subgroups of the match, from 1.\n\
    The default argument is used for groups\n\
    that did not participate in the match");

PyDoc_STRVAR(match_groupdict_doc,
"groupdict([default=None]) -> dict.\n\
    Return a dictionary containing all the named subgroups of the match,\n\
    keyed by the subgroup name. The default argument is used for groups\n\
    that did not participate in the match");

PyDoc_STRVAR(match_expand_doc,
"expand(template) -> str.\n\
    Return the string obtained by doing backslash substitution\n\
    on the string template, as done by the sub() method.");

static PyMethodDef match_methods[] = {
    {"group", (PyCFunction) match_group, METH_VARARGS, match_group_doc},
    {"start", (PyCFunction) match_start, METH_VARARGS, match_start_doc},
    {"end", (PyCFunction) match_end, METH_VARARGS, match_end_doc},
    {"span", (PyCFunction) match_span, METH_VARARGS, match_span_doc},
    {"groups", (PyCFunction) match_groups, METH_VARARGS|METH_KEYWORDS,
        match_groups_doc},
    {"groupdict", (PyCFunction) match_groupdict, METH_VARARGS|METH_KEYWORDS,
        match_groupdict_doc},
    {"expand", (PyCFunction) match_expand, METH_O, match_expand_doc},
    {"__copy__", (PyCFunction) match_copy, METH_NOARGS},
    {"__deepcopy__", (PyCFunction) match_deepcopy, METH_O},
    {NULL, NULL}
};

static PyObject *
match_lastindex_get(MatchObject *self)
{
    if (self->lastindex >= 0)
        return PyInt_FromSsize_t(self->lastindex);
    Py_INCREF(Py_None);
    return Py_None;
}

static PyObject *
match_lastgroup_get(MatchObject *self)
{
    if (self->pattern->indexgroup && self->lastindex >= 0) {
        PyObject* result = PySequence_GetItem(
            self->pattern->indexgroup, self->lastindex
            );
        if (result)
            return result;
        PyErr_Clear();
    }
    Py_INCREF(Py_None);
    return Py_None;
}

static PyObject *
match_regs_get(MatchObject *self)
{
    if (self->regs) {
        Py_INCREF(self->regs);
        return self->regs;
    } else
        return match_regs(self);
}

static PyGetSetDef match_getset[] = {
    {"lastindex", (getter)match_lastindex_get, (setter)NULL},
    {"lastgroup", (getter)match_lastgroup_get, (setter)NULL},
    {"regs",      (getter)match_regs_get,      (setter)NULL},
    {NULL}
};

#define MATCH_OFF(x) offsetof(MatchObject, x)
static PyMemberDef match_members[] = {
    {"string",  T_OBJECT,   MATCH_OFF(string),  READONLY},
    {"re",      T_OBJECT,   MATCH_OFF(pattern), READONLY},
    {"pos",     T_PYSSIZET, MATCH_OFF(pos),     READONLY},
    {"endpos",  T_PYSSIZET, MATCH_OFF(endpos),  READONLY},
    {NULL}
};


/* FIXME: implement setattr("string", None) as a special case (to
   detach the associated string, if any */

static PyTypeObject Match_Type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    "_" SRE_MODULE ".SRE_Match",
    sizeof(MatchObject), sizeof(Py_ssize_t),
    (destructor)match_dealloc,  /* tp_dealloc */
    0,                          /* tp_print */
    0,                          /* tp_getattr */
    0,                          /* tp_setattr */
    0,                          /* tp_compare */
    0,                          /* tp_repr */
    0,                          /* tp_as_number */
    0,                          /* tp_as_sequence */
    0,                          /* tp_as_mapping */
    0,                          /* tp_hash */
    0,                          /* tp_call */
    0,                          /* tp_str */
    0,                          /* tp_getattro */
    0,                          /* tp_setattro */
    0,                          /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT,
    match_doc,                  /* tp_doc */
    0,                          /* tp_traverse */
    0,                          /* tp_clear */
    0,                          /* tp_richcompare */
    0,                          /* tp_weaklistoffset */
    0,                          /* tp_iter */
    0,                          /* tp_iternext */
    match_methods,    /* tp_methods */
    match_members,    /* tp_members */
    match_getset,           /* tp_getset */
};

static PyObject*
pattern_new_match(PatternObject* pattern, SRE_STATE* state, int status)
{
    /* create match object (from state object) */

    MatchObject* match;
    Py_ssize_t i, j;
    char* base;
    int n;

    if (status > 0) {

        /* create match object (with room for extra group marks) */
        /* coverity[ampersand_in_size] */
        match = PyObject_NEW_VAR(MatchObject, &Match_Type,
                                 2*(pattern->groups+1));
        if (!match)
            return NULL;

        Py_INCREF(pattern);
        match->pattern = pattern;

        Py_INCREF(state->string);
        match->string = state->string;

        match->regs = NULL;
        match->groups = pattern->groups+1;

        /* fill in group slices */

        base = (char*) state->beginning;
        n = state->charsize;

        match->mark[0] = ((char*) state->start - base) / n;
        match->mark[1] = ((char*) state->ptr - base) / n;

        for (i = j = 0; i < pattern->groups; i++, j+=2)
            if (j+1 <= state->lastmark && state->mark[j] && state->mark[j+1]) {
                match->mark[j+2] = ((char*) state->mark[j] - base) / n;
                match->mark[j+3] = ((char*) state->mark[j+1] - base) / n;
            } else
                match->mark[j+2] = match->mark[j+3] = -1; /* undefined */

        match->pos = state->pos;
        match->endpos = state->endpos;

        match->lastindex = state->lastindex;

        return (PyObject*) match;

    } else if (status == 0) {

        /* no match */
        Py_INCREF(Py_None);
        return Py_None;

    }

    /* internal error */
    pattern_error(status);
    return NULL;
}


/* -------------------------------------------------------------------- */
/* scanner methods (experimental) */

static void
scanner_dealloc(ScannerObject* self)
{
    state_fini(&self->state);
    Py_XDECREF(self->pattern);
    PyObject_DEL(self);
}

static PyObject*
scanner_match(ScannerObject* self, PyObject *unused)
{
    SRE_STATE* state = &self->state;
    PyObject* match;
    int status;

    state_reset(state);

    state->ptr = state->start;

    if (state->charsize == 1) {
        status = sre_match(state, PatternObject_GetCode(self->pattern));
    } else {
#if defined(HAVE_UNICODE)
        status = sre_umatch(state, PatternObject_GetCode(self->pattern));
#endif
    }
    if (PyErr_Occurred())
        return NULL;

    match = pattern_new_match((PatternObject*) self->pattern,
                               state, status);

    if (status == 0 || state->ptr == state->start)
        state->start = (void*) ((char*) state->ptr + state->charsize);
    else
        state->start = state->ptr;

    return match;
}


static PyObject*
scanner_search(ScannerObject* self, PyObject *unused)
{
    SRE_STATE* state = &self->state;
    PyObject* match;
    int status;

    state_reset(state);

    state->ptr = state->start;

    if (state->charsize == 1) {
        status = sre_search(state, PatternObject_GetCode(self->pattern));
    } else {
#if defined(HAVE_UNICODE)
        status = sre_usearch(state, PatternObject_GetCode(self->pattern));
#endif
    }
    if (PyErr_Occurred())
        return NULL;

    match = pattern_new_match((PatternObject*) self->pattern,
                               state, status);

    if (status == 0 || state->ptr == state->start)
        state->start = (void*) ((char*) state->ptr + state->charsize);
    else
        state->start = state->ptr;

    return match;
}

static PyMethodDef scanner_methods[] = {
    {"match", (PyCFunction) scanner_match, METH_NOARGS},
    {"search", (PyCFunction) scanner_search, METH_NOARGS},
    {NULL, NULL}
};

#define SCAN_OFF(x) offsetof(ScannerObject, x)
static PyMemberDef scanner_members[] = {
    {"pattern", T_OBJECT, SCAN_OFF(pattern),  READONLY},
    {NULL}  /* Sentinel */
};

statichere PyTypeObject Scanner_Type = {
    PyObject_HEAD_INIT(NULL)
    0, "_" SRE_MODULE ".SRE_Scanner",
    sizeof(ScannerObject), 0,
    (destructor)scanner_dealloc, /*tp_dealloc*/
    0,        /* tp_print */
    0,        /* tp_getattr */
    0,        /* tp_setattr */
    0,        /* tp_reserved */
    0,        /* tp_repr */
    0,        /* tp_as_number */
    0,        /* tp_as_sequence */
    0,        /* tp_as_mapping */
    0,        /* tp_hash */
    0,        /* tp_call */
    0,        /* tp_str */
    0,        /* tp_getattro */
    0,        /* tp_setattro */
    0,        /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT,   /* tp_flags */
    0,        /* tp_doc */
    0,        /* tp_traverse */
    0,        /* tp_clear */
    0,        /* tp_richcompare */
    0,        /* tp_weaklistoffset */
    0,        /* tp_iter */
    0,        /* tp_iternext */
    scanner_methods,    /* tp_methods */
    scanner_members,    /* tp_members */
    0,        /* tp_getset */
};

static PyObject*
pattern_scanner(PatternObject* pattern, PyObject* args)
{
    /* create search state object */

    ScannerObject* self;

    PyObject* string;
    Py_ssize_t start = 0;
    Py_ssize_t end = PY_SSIZE_T_MAX;
    if (!PyArg_ParseTuple(args, "O|nn:scanner", &string, &start, &end))
        return NULL;

    /* create scanner object */
    self = PyObject_NEW(ScannerObject, &Scanner_Type);
    if (!self)
        return NULL;
    self->pattern = NULL;

    string = state_init(&self->state, pattern, string, start, end);
    if (!string) {
        Py_DECREF(self);
        return NULL;
    }

    Py_INCREF(pattern);
    self->pattern = (PyObject*) pattern;

    return (PyObject*) self;
}

static PyMethodDef _functions[] = {
    {"compile", _compile, METH_VARARGS},
    {"getcodesize", sre_codesize, METH_NOARGS},
    {"getlower", sre_getlower, METH_VARARGS},
    {NULL, NULL}
};

#if PY_VERSION_HEX < 0x02030000
DL_EXPORT(void) init_sre(void)
#else
PyMODINIT_FUNC init_sre(void)
#endif
{
    PyObject* m;
    PyObject* d;
    PyObject* x;

    /* Patch object types */
    if (PyType_Ready(&Pattern_Type) || PyType_Ready(&Match_Type) ||
        PyType_Ready(&Scanner_Type))
        return;

    m = Py_InitModule("_" SRE_MODULE, _functions);
    if (m == NULL)
      return;
    d = PyModule_GetDict(m);

    x = PyInt_FromLong(SRE_MAGIC);
    if (x) {
        PyDict_SetItemString(d, "MAGIC", x);
        Py_DECREF(x);
    }

    x = PyInt_FromLong(sizeof(SRE_CODE));
    if (x) {
        PyDict_SetItemString(d, "CODESIZE", x);
        Py_DECREF(x);
    }

    x = PyLong_FromUnsignedLong(SRE_MAXREPEAT);
    if (x) {
        PyDict_SetItemString(d, "MAXREPEAT", x);
        Py_DECREF(x);
    }

    x = PyString_FromString(copyright);
    if (x) {
        PyDict_SetItemString(d, "copyright", x);
        Py_DECREF(x);
    }
}

#endif /* !defined(SRE_RECURSIVE) */

/* vim:ts=4:sw=4:et
*/