qregexp3.cpp

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/****************************************************************************
** $Id: qregexp3.cpp,v 1.3 2005/01/21 19:56:17 ar Exp $
**
** Implementation of QRegExp class
**
** Created : 950126
**
** Copyright (C) 1992-2000 Trolltech AS.  All rights reserved.
**
** This file is part of the tools module of the Qt GUI Toolkit.
**
** This file may be distributed under the terms of the Q Public License
** as defined by Trolltech AS of Norway and appearing in the file
** LICENSE.QPL included in the packaging of this file.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** Licensees holding valid Qt Enterprise Edition or Qt Professional Edition
** licenses may use this file in accordance with the Qt Commercial License
** Agreement provided with the Software.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
**   information about Qt Commercial License Agreements.
** See http://www.trolltech.com/qpl/ for QPL licensing information.
** See http://www.trolltech.com/gpl/ for GPL licensing information.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
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**********************************************************************/
#if QT_VERSION >= 0x030000
#error QRegExp3 is now in QT 3 use QRegExp instead
#endif

#if QT_VERSION < 0x030000
#include "./qregexp3.h"
#else
#include "qregexp.h"
#endif

/* OPIE */
#include <opie2/odebug.h>

/* QT */
#include <qarray.h>
#include <qbitarray.h>
#include <qcache.h>
#include <qintdict.h>
#include <qmap.h>
#include <qstring.h>
#include <qtl.h>
#include <qvector.h>

/* STD */
#include <limits.h>

/*
  WARNING!  Be sure to read qregexp.tex before modifying this file.
*/

static const int NumBadChars = 128;
#define BadChar( ch ) ( (ch).cell() % NumBadChars )

static const int NoOccurrence = INT_MAX;
static const int EmptyCapture = INT_MAX;
static const int InftyLen = INT_MAX;
static const int InftyRep = 1000;
static const int EOS = -1;

#ifndef QT_NO_REGEXP_OPTIM
static int engCount = 0;
static QArray<int> *noOccurrences = 0;
static QArray<int> *firstOccurrenceAtZero = 0;
#endif

/*
  Merges two QArrays of ints and puts the result into the first one.
*/
static void mergeInto( QArray<int> *a, const QArray<int>& b )
{
    int asize = a->size();
    int bsize = b.size();
    if ( asize == 0 ) {
    *a = b.copy();
#ifndef QT_NO_REGEXP_OPTIM
    } else if ( bsize == 1 && (*a)[asize - 1] < b[0] ) {
    a->resize( asize + 1 );
    (*a)[asize] = b[0];
#endif
    } else if ( bsize >= 1 ) {
    int csize = asize + bsize;
    QArray<int> c( csize );
    int i = 0, j = 0, k = 0;
    while ( i < asize ) {
        if ( j < bsize ) {
        if ( (*a)[i] == b[j] ) {
            i++;
            csize--;
        } else if ( (*a)[i] < b[j] ) {
            c[k++] = (*a)[i++];
        } else {
            c[k++] = b[j++];
        }
        } else {
        memcpy( c.data() + k, (*a).data() + i,
            (asize - i) * sizeof(int) );
        break;
        }
    }
    c.resize( csize );
    if ( j < bsize )
        memcpy( c.data() + k, b.data() + j, (bsize - j) * sizeof(int) );
    *a = c;
    }
}

/*
  Merges two disjoint QMaps of (int, int) pairs and puts the result into the
  first one.
*/
static void mergeInto( QMap<int, int> *a, const QMap<int, int>& b )
{
    QMap<int, int>::ConstIterator it;
    for ( it = b.begin(); it != b.end(); ++it )
    a->insert( it.key(), *it );
}

/*
  Returns the value associated to key k in QMap m of (int, int) pairs, or 0 if
  no such value is explicitly present.
*/
static int at( const QMap<int, int>& m, int k )
{
    QMap<int, int>::ConstIterator it = m.find( k );
    if ( it == m.end() )
    return 0;
    else
    return *it;
}

#ifndef QT_NO_REGEXP_WILDCARD
/*
  Translates a wildcard pattern to an equivalent regular expression pattern
  (e.g., *.cpp to .*\.cpp).
*/
static QString wc2rx( const QString& wc )
{
    int wclen = wc.length();
    QString rx = QString::fromLatin1( "" );
    int i = 0;
    while ( i < wclen ) {
    QChar c = wc[i++];
    switch ( c.unicode() ) {
    case '*':
        rx += QString::fromLatin1( ".*" );
        break;
    case '?':
        rx += QChar( '.' );
        break;
    case '$':
    case '(':
    case ')':
    case '+':
    case '.':
    case '\\':
    case '^':
    case '{':
    case '|':
    case '}':
        rx += QChar( '\\' );
        rx += c;
        break;
    case '[':
        rx += c;
        if ( wc[i] == QChar('^') )
        rx += wc[i++];
        if ( i < wclen ) {
        if ( rx[i] == ']' )
            rx += wc[i++];
        while ( i < wclen && wc[i] != QChar(']') ) {
            if ( wc[i] == '\\' )
            rx += QChar( '\\' );
            rx += wc[i++];
        }
        }
        break;
    default:
        rx += c;
    }
    }
    return rx;
}
#endif

/*
  The class QRegExpEngine encapsulates a modified nondeterministic finite
  automaton (NFA).
*/
class QRegExpEngine : public QShared
{
public:
#ifndef QT_NO_REGEXP_CCLASS
    /*
      The class CharClass represents a set of characters, such as can be found
      in regular expressions (e.g., [a-z] denotes the set {a, b, ..., z}).
    */
    class CharClass
    {
    public:
    CharClass();
    CharClass( const CharClass& cc ) { operator=( cc ); }

    CharClass& operator=( const CharClass& cc );

    void clear();
    bool negative() const { return n; }
    void setNegative( bool negative );
    void addCategories( int cats );
    void addRange( ushort from, ushort to );
    void addSingleton( ushort ch ) { addRange( ch, ch ); }

    bool in( QChar ch ) const;
#ifndef QT_NO_REGEXP_OPTIM
    const QArray<int>& firstOccurrence() const { return occ1; }
#endif

#if defined(QT_DEBUG)
    void dump() const;
#endif

    private:
    /*
      The struct Range represents a range of characters (e.g., [0-9] denotes
      range 48 to 57).
    */
    struct Range
    {
        ushort from; // 48
        ushort to; // 57
    };

    int c; // character classes
    QArray<Range> r; // character ranges
    bool n; // negative?
#ifndef QT_NO_REGEXP_OPTIM
    QArray<int> occ1; // first-occurrence array
#endif
    };
#else
    struct CharClass
    {
    int x; // dummy

#ifndef QT_NO_REGEXP_OPTIM
    const QArray<int>& firstOccurrence() const {
        return *firstOccurrenceAtZero;
    }
#endif
    };
#endif

    QRegExpEngine( bool caseSensitive ) { setup( caseSensitive ); }
    QRegExpEngine( const QString& rx, bool caseSensitive );
#ifndef QT_NO_REGEXP_OPTIM
    ~QRegExpEngine();
#endif

    bool isValid() const { return valid; }
    bool caseSensitive() const { return cs; }
    int numCaptures() const { return realncap; }
    QArray<int> match( const QString& str, int pos, bool minimal,
               bool oneTest );
    int matchedLength() const { return mmMatchedLen; }

    int createState( QChar ch );
    int createState( const CharClass& cc );
#ifndef QT_NO_REGEXP_BACKREF
    int createState( int bref );
#endif

    void addCatTransitions( const QArray<int>& from, const QArray<int>& to );
#ifndef QT_NO_REGEXP_CAPTURE
    void addPlusTransitions( const QArray<int>& from, const QArray<int>& to,
                 int atom );
#endif

#ifndef QT_NO_REGEXP_ANCHOR_ALT
    int anchorAlternation( int a, int b );
    int anchorConcatenation( int a, int b );
#else
    int anchorAlternation( int a, int b ) { return a & b; }
    int anchorConcatenation( int a, int b ) { return a | b; }
#endif
    void addAnchors( int from, int to, int a );

#ifndef QT_NO_REGEXP_OPTIM
    void setupGoodStringHeuristic( int earlyStart, int lateStart,
                   const QString& str );
    void setupBadCharHeuristic( int minLen, const QArray<int>& firstOcc );
    void heuristicallyChooseHeuristic();
#endif

#if defined(QT_DEBUG)
    void dump() const;
#endif

private:
    enum { CharClassBit = 0x10000, BackRefBit = 0x20000 };

    /*
      The struct State represents one state in a modified NFA.  The input
      characters matched are stored in the state instead of on the transitions,
      something possible for an automaton constructed from a regular expression.
    */
    struct State
    {
#ifndef QT_NO_REGEXP_CAPTURE
    int atom; // which atom does this state belong to?
#endif
    int match; // what does it match? (see CharClassBit and BackRefBit)
    QArray<int> outs; // out-transitions
    QMap<int, int> *reenter; // atoms reentered when transiting out
    QMap<int, int> *anchors; // anchors met when transiting out

#ifndef QT_NO_REGEXP_CAPTURE
    State( int a, int m )
        : atom( a ), match( m ), reenter( 0 ), anchors( 0 ) { }
#else
    State( int m )
        : match( m ), reenter( 0 ), anchors( 0 ) { }
#endif
    ~State() { delete reenter; delete anchors; }
    };

#ifndef QT_NO_REGEXP_LOOKAHEAD
    /*
      The struct Lookahead represents a lookahead a la Perl (e.g., (?=foo) and
      (?!bar)).
    */
    struct Lookahead
    {
    QRegExpEngine *eng; // NFA representing the embedded regular expression
    bool neg; // negative lookahead?

    Lookahead( QRegExpEngine *eng0, bool neg0 )
        : eng( eng0 ), neg( neg0 ) { }
    ~Lookahead() { delete eng; }
    };
#endif

#ifndef QT_NO_REGEXP_CAPTURE
    /*
      The struct Atom represents one node in the hierarchy of regular expression
      atoms.
    */
    struct Atom
    {
    int parent; // index of parent in array of atoms
    int capture; // index of capture, from 1 to ncap
    };
#endif

#ifndef QT_NO_REGEXP_ANCHOR_ALT
    /*
      The struct AnchorAlternation represents a pair of anchors with OR
      semantics.
    */
    struct AnchorAlternation
    {
    int a; // this anchor...
    int b; // ...or this one
    };
#endif

    enum { InitialState = 0, FinalState = 1 };
    void setup( bool caseSensitive );
    int setupState( int match );

    /*
      Let's hope that 13 lookaheads and 14 back-references are enough.
     */
    enum { MaxLookaheads = 13, MaxBackRefs = 14 };
    enum { Anchor_Dollar = 0x00000001, Anchor_Caret = 0x00000002,
       Anchor_Word = 0x00000004, Anchor_NonWord = 0x00000008,
       Anchor_FirstLookahead = 0x00000010,
       Anchor_BackRef1Empty = Anchor_FirstLookahead << MaxLookaheads,
       Anchor_BackRef0Empty = Anchor_BackRef1Empty >> 1,
       Anchor_Alternation = Anchor_BackRef1Empty << MaxBackRefs,

       Anchor_LookaheadMask = ( Anchor_FirstLookahead - 1 ) ^
           ( (Anchor_FirstLookahead << MaxLookaheads) - 1 ) };
#ifndef QT_NO_REGEXP_CAPTURE
    int startAtom( bool capture );
    void finishAtom( int atom ) { cf = f[atom].parent; }
#endif

#ifndef QT_NO_REGEXP_LOOKAHEAD
    int addLookahead( QRegExpEngine *eng, bool negative );
#endif

#ifndef QT_NO_REGEXP_CAPTURE
    bool isBetterCapture( const int *begin1, const int *end1, const int *begin2,
              const int *end2 );
#endif
    bool testAnchor( int i, int a, const int *capBegin );

#ifndef QT_NO_REGEXP_OPTIM
    bool goodStringMatch();
    bool badCharMatch();
#else
    bool bruteMatch();
#endif
    bool matchHere();

    QVector<State> s; // array of states
    int ns; // number of states
#ifndef QT_NO_REGEXP_CAPTURE
    QArray<Atom> f; // atom hierarchy
    int nf; // number of atoms
    int cf; // current atom
#endif
    int realncap; // number of captures, seen from the outside
    int ncap; // number of captures, seen from the inside
#ifndef QT_NO_REGEXP_CCLASS
    QVector<CharClass> cl; // array of character classes
#endif
#ifndef QT_NO_REGEXP_LOOKAHEAD
    QVector<Lookahead> ahead; // array of lookaheads
#endif
#ifndef QT_NO_REGEXP_ANCHOR_ALT
    QArray<AnchorAlternation> aa; // array of (a, b) pairs of anchors
#endif
#ifndef QT_NO_REGEXP_OPTIM
    bool caretAnchored; // does the regexp start with ^?
#endif
    bool valid; // is the regular expression valid?
    bool cs; // case sensitive?
#ifndef QT_NO_REGEXP_BACKREF
    int nbrefs; // number of back-references
#endif

#ifndef QT_NO_REGEXP_OPTIM
    bool useGoodStringHeuristic; // use goodStringMatch? otherwise badCharMatch

    int goodEarlyStart; // the index where goodStr can first occur in a match
    int goodLateStart; // the index where goodStr can last occur in a match
    QString goodStr; // the string that any match has to contain

    int minl; // the minimum length of a match
    QArray<int> occ1; // first-occurrence array
#endif

    /*
      The class Box is an abstraction for a regular expression fragment.  It can
      also be seen as one node in the syntax tree of a regular expression with
      synthetized attributes.

      It's interface is ugly for performance reasons.
    */
    class Box
    {
    public:
    Box( QRegExpEngine *engine );
    Box( const Box& b ) { operator=( b ); }

    Box& operator=( const Box& b );

    void clear() { operator=(Box(eng)); }
    void set( QChar ch );
    void set( const CharClass& cc );
#ifndef QT_NO_REGEXP_BACKREF
    void set( int bref );
#endif

    void cat( const Box& b );
    void orx( const Box& b );
    void plus( int atom );
    void opt();
    void catAnchor( int a );
#ifndef QT_NO_REGEXP_OPTIM
    void setupHeuristics();
#endif

#if defined(QT_DEBUG)
    void dump() const;
#endif

    private:
    void addAnchorsToEngine( const Box& to ) const;

    QRegExpEngine *eng; // the automaton under construction
    QArray<int> ls; // the left states (firstpos)
    QArray<int> rs; // the right states (lastpos)
    QMap<int, int> lanchors; // the left anchors
    QMap<int, int> ranchors; // the right anchors
    int skipanchors; // the anchors to match if the box is skipped

#ifndef QT_NO_REGEXP_OPTIM
    int earlyStart; // the index where str can first occur
    int lateStart; // the index where str can last occur
    QString str; // a string that has to occur in any match
    QString leftStr; // a string occurring at the left of this box
    QString rightStr; // a string occurring at the right of this box
    int maxl; // the maximum length of this box (possibly InftyLen)
#endif

    int minl; // the minimum length of this box
#ifndef QT_NO_REGEXP_OPTIM
    QArray<int> occ1; // first-occurrence array
#endif
    };
    friend class Box;

    /*
      This is the lexical analyzer for regular expressions.
    */
    enum { Tok_Eos, Tok_Dollar, Tok_LeftParen, Tok_MagicLeftParen,
       Tok_PosLookahead, Tok_NegLookahead, Tok_RightParen, Tok_CharClass,
       Tok_Caret, Tok_Quantifier, Tok_Bar, Tok_Word, Tok_NonWord,
       Tok_Char = 0x10000, Tok_BackRef = 0x20000 };
    int getChar();
    int getEscape();
#ifndef QT_NO_REGEXP_INTERVAL
    int getRep( int def );
#endif
#ifndef QT_NO_REGEXP_LOOKAHEAD
    void skipChars( int n );
#endif
    void startTokenizer( const QChar *rx, int len );
    int getToken();

    const QChar *yyIn; // a pointer to the input regular expression pattern
    int yyPos0; // the position of yyTok in the input pattern
    int yyPos; // the position of the next character to read
    int yyLen; // the length of yyIn
    int yyCh; // the last character read
    CharClass *yyCharClass; // attribute for Tok_CharClass tokens
    int yyMinRep; // attribute for Tok_Quantifier
    int yyMaxRep; // ditto
    bool yyError; // syntax error or overflow during parsing?

    /*
      This is the syntactic analyzer for regular expressions.
    */
    int parse( const QChar *rx, int len );
    void parseAtom( Box *box );
    void parseFactor( Box *box );
    void parseTerm( Box *box );
    void parseExpression( Box *box );

    int yyTok; // the last token read
    bool yyMayCapture; // set this to FALSE to disable capturing

    /*
      This is the engine state during matching.
    */
    const QString *mmStr; // a pointer to the input QString
    const QChar *mmIn; // a pointer to the input string data
    int mmPos; // the current position in the string
    int mmLen; // the length of the input string
    bool mmMinimal; // minimal matching?
    QArray<int> mmCaptured; // an array of pairs (start, len)
    QArray<int> mmCapturedNoMatch; // an array of pairs (-1, -1)
    QArray<int> mmBigArray; // big QArray<int> array
    int *mmInNextStack; // is state is mmNextStack?
    int *mmCurStack; // stack of current states
    int *mmNextStack; // stack of next states
    int *mmCurCapBegin; // start of current states' captures
    int *mmNextCapBegin; // start of next states' captures
    int *mmCurCapEnd; // end of current states' captures
    int *mmNextCapEnd; // end of next states' captures
    int *mmTempCapBegin; // start of temporary captures
    int *mmTempCapEnd; // end of temporary captures
    int *mmCapBegin; // start of captures for a next state
    int *mmCapEnd; // end of captures for a next state
    int *mmSlideTab; // bump-along slide table for bad-character heuristic
    int mmSlideTabSize; // size of slide table
#ifndef QT_NO_REGEXP_BACKREF
    QIntDict<int> mmSleeping; // dictionary of back-reference sleepers
#endif
    int mmMatchedLen; // length of match or of matched string for partial match
};

QRegExpEngine::QRegExpEngine( const QString& rx, bool caseSensitive )
#ifndef QT_NO_REGEXP_BACKREF
    : mmSleeping( 101 )
#endif
{
    setup( caseSensitive );
    valid = ( parse(rx.unicode(), rx.length()) == (int) rx.length() );
}

#ifndef QT_NO_REGEXP_OPTIM
QRegExpEngine::~QRegExpEngine()
{
    if ( --engCount == 0 ) {
    delete noOccurrences;
    noOccurrences = 0;
    delete firstOccurrenceAtZero;
    firstOccurrenceAtZero = 0;
    }
}
#endif

/*
  Tries to match in str and returns an array of (begin, length) pairs for
  captured text.  If there is no match, all pairs are (-1, -1).
*/
QArray<int> QRegExpEngine::match( const QString& str, int pos, bool minimal,
                  bool oneTest )
{
    mmStr = &str;
    mmIn = str.unicode();
    if ( mmIn == 0 )
    mmIn = &QChar::null;
    mmPos = pos;
    mmLen = str.length();
    mmMinimal = minimal;
    mmMatchedLen = 0;

    bool matched = FALSE;
    if ( valid && mmPos >= 0 && mmPos <= mmLen ) {
#ifndef QT_NO_REGEXP_OPTIM
    if ( mmPos <= mmLen - minl ) {
        if ( caretAnchored || oneTest )
        matched = matchHere();
        else if ( useGoodStringHeuristic )
        matched = goodStringMatch();
        else
        matched = badCharMatch();
    }
#else
    matched = oneTest ? matchHere() : bruteMatch();
#endif
    }

    if ( matched ) {
    mmCaptured.detach();
    mmCaptured[0] = mmPos;
    mmCaptured[1] = mmMatchedLen;
    for ( int j = 0; j < realncap; j++ ) {
        int len = mmCapEnd[j] - mmCapBegin[j];
        mmCaptured[2 + 2 * j] = len > 0 ? mmPos + mmCapBegin[j] : 0;
        mmCaptured[2 + 2 * j + 1] = len;
    }
    return mmCaptured;
    } else {
    return mmCapturedNoMatch;
    }
}

/*
  The three following functions add one state to the automaton and return the
  number of the state.
*/

int QRegExpEngine::createState( QChar ch )
{
    return setupState( ch.unicode() );
}

int QRegExpEngine::createState( const CharClass& cc )
{
#ifndef QT_NO_REGEXP_CCLASS
    int n = cl.size();
    cl.resize( n + 1 );
    cl.insert( n, new CharClass(cc) );
    return setupState( CharClassBit | n );
#else
    Q_UNUSED( cc );
    return setupState( CharClassBit );
#endif
}

#ifndef QT_NO_REGEXP_BACKREF
int QRegExpEngine::createState( int bref )
{
    if ( bref > nbrefs ) {
    nbrefs = bref;
    if ( nbrefs > MaxBackRefs ) {
        yyError = TRUE;
        return 0;
    }
    }
    return setupState( BackRefBit | bref );
}
#endif

/*
  The two following functions add a transition between all pairs of states
  (i, j) where i is fond in from, and j is found in to.

  Cat-transitions are distinguished from plus-transitions for capturing.
*/

void QRegExpEngine::addCatTransitions( const QArray<int>& from,
                       const QArray<int>& to )
{
    for ( int i = 0; i < (int) from.size(); i++ ) {
    State *st = s[from[i]];
    mergeInto( &st->outs, to );
    }
}

#ifndef QT_NO_REGEXP_CAPTURE
void QRegExpEngine::addPlusTransitions( const QArray<int>& from,
                    const QArray<int>& to, int atom )
{
    for ( int i = 0; i < (int) from.size(); i++ ) {
    State *st = s[from[i]];
    QArray<int> oldOuts = st->outs.copy();
    mergeInto( &st->outs, to );
    if ( f[atom].capture >= 0 ) {
        if ( st->reenter == 0 )
        st->reenter = new QMap<int, int>;
        for ( int j = 0; j < (int) to.size(); j++ ) {
        if ( !st->reenter->contains(to[j]) &&
             oldOuts.bsearch(to[j]) < 0 )
            st->reenter->insert( to[j], atom );
        }
    }
    }
}
#endif

#ifndef QT_NO_REGEXP_ANCHOR_ALT
/*
  Returns an anchor that means a OR b.
*/
int QRegExpEngine::anchorAlternation( int a, int b )
{
    if ( ((a & b) == a || (a & b) == b) && ((a | b) & Anchor_Alternation) == 0 )
    return a & b;

    int n = aa.size();
    aa.resize( n + 1 );
    aa[n].a = a;
    aa[n].b = b;
    return Anchor_Alternation | n;
}

/*
  Returns an anchor that means a AND b.
*/
int QRegExpEngine::anchorConcatenation( int a, int b )
{
    if ( ((a | b) & Anchor_Alternation) == 0 )
    return a | b;
    if ( (b & Anchor_Alternation) != 0 )
    qSwap( a, b );
    int aprime = anchorConcatenation( aa[a ^ Anchor_Alternation].a, b );
    int bprime = anchorConcatenation( aa[a ^ Anchor_Alternation].b, b );
    return anchorAlternation( aprime, bprime );
}
#endif

/*
  Adds anchor a on a transition caracterised by its from state and its to state.
*/
void QRegExpEngine::addAnchors( int from, int to, int a )
{
    State *st = s[from];
    if ( st->anchors == 0 )
    st->anchors = new QMap<int, int>;
    if ( st->anchors->contains(to) )
    a = anchorAlternation( (*st->anchors)[to], a );
    st->anchors->insert( to, a );
}

#ifndef QT_NO_REGEXP_OPTIM
/*
  The two following functions provide the engine with the information needed by
  its matching heuristics.
*/

void QRegExpEngine::setupGoodStringHeuristic( int earlyStart, int lateStart,
                          const QString& str )
{
    goodEarlyStart = earlyStart;
    goodLateStart = lateStart;
    goodStr = cs ? str : str.lower();
}

void QRegExpEngine::setupBadCharHeuristic( int minLen,
                       const QArray<int>& firstOcc )
{
    minl = minLen;
    occ1 = cs ? firstOcc : *firstOccurrenceAtZero;
}

/*
  This function chooses between the good-string and the bad-character
  heuristics.  It computes two scores and chooses the heuristic with the highest
  score.

  Here are some common-sense constraints on the scores that should be respected
  if the formulas are ever modified:  (1) If goodStr is empty, the good-string
  heuristic scores 0.  (2) If the search is case insensitive, the good-string
  heuristic should be used, unless it scores 0.  (Case insensitivity
  turns all entries of occ1 to 0.)  (3) If (goodLateStart - goodEarlyStart) is
  big, the good-string heuristic should score less.
*/
void QRegExpEngine::heuristicallyChooseHeuristic()
{
    int i;

    if ( minl == 0 )
    return;

    /*
      Magic formula:  The good string has to constitute a good proportion of the
      minimum-length string, and appear at a more-or-less known index.
    */
    int goodStringScore = ( 64 * goodStr.length() / minl ) -
              ( goodLateStart - goodEarlyStart );

    /*
      Less magic formula:  We pick a couple of characters at random, and check
      whether they are good or bad.
    */
    int badCharScore = 0;
    int step = QMAX( 1, NumBadChars / 32 );
    for ( i = 1; i < NumBadChars; i += step ) {
    if ( occ1[i] == NoOccurrence )
        badCharScore += minl;
    else
        badCharScore += occ1[i];
    }
    badCharScore /= minl;

    useGoodStringHeuristic = ( goodStringScore > badCharScore );
}
#endif

#if defined(QT_DEBUG)
void QRegExpEngine::dump() const
{
    int i, j;
    odebug << "Case " << (cs ? "" : "in") << "sensitive engine" << oendl;
    odebug << "  States" << oendl;
    for ( i = 0; i < ns; i++ ) {
    odebug << "  " << i
           << (i == InitialState ? " (initial)" : i == FinalState ? " (final)" : "") << oendl;

#ifndef QT_NO_REGEXP_CAPTURE
    odebug << "    in atom " << s[i]->atom << oendl;
#endif
    int m = s[i]->match;
    if ( (m & CharClassBit) != 0 ) {
        odebug << "    match character class " << (m ^ CharClassBit) << oendl;
#ifndef QT_NO_REGEXP_CCLASS
        cl[m ^ CharClassBit]->dump();
#else
        odebug << "    negative character class" << oendl;
#endif
    } else if ( (m & BackRefBit) != 0 ) {
        odebug << "    match back-reference " << (m ^ BackRefBit) << oendl;
    } else if ( m >= 0x20 && m <= 0x7e ) {
        odebug << "    match " << QString().sprintf( "0x%.4x", m) << " (" << m << ")" << oendl;

    } else {
        odebug << "    match " << QString().sprintf( "0x%.4x", m) << oendl;
    }
    for ( j = 0; j < (int) s[i]->outs.size(); j++ ) {
        int next = s[i]->outs[j];
        odebug << "    -> " << next << oendl;
        if ( s[i]->reenter != 0 && s[i]->reenter->contains(next) )
        odebug << "       [reenter " << (*s[i]->reenter)[next] << "]" << oendl;
        if ( s[i]->anchors != 0 && at(*s[i]->anchors, next) != 0 )
        odebug << "       [anchors " << QString().sprintf( "0x%.8x]", (*s[i]->anchors)[next] ) << oendl;
    }
    }
#ifndef QT_NO_REGEXP_CAPTURE
    if ( nf > 0 ) {
    odebug << "  Atom    Parent  Capture" << oendl;
    for ( i = 0; i < nf; i++ )
        odebug << QString().sprintf("  %6d  %6d  %6d", i, f[i].parent, f[i].capture ) << oendl;
    }
#endif
#ifndef QT_NO_REGEXP_ANCHOR_ALT
    for ( i = 0; i < (int) aa.size(); i++ )
    odebug << QString().sprintf("  Anchor alternation 0x%.8x: 0x%.8x 0x%.9x", i, aa[i].a, aa[i].b ) << oendl;
#endif
}
#endif

void QRegExpEngine::setup( bool caseSensitive )
{
#ifndef QT_NO_REGEXP_OPTIM
    if ( engCount++ == 0 ) {
    noOccurrences = new QArray<int>( NumBadChars );
    firstOccurrenceAtZero = new QArray<int>( NumBadChars );
    noOccurrences->fill( NoOccurrence );
    firstOccurrenceAtZero->fill( 0 );
    }
#endif
    s.setAutoDelete( TRUE );
    s.resize( 32 );
    ns = 0;
#ifndef QT_NO_REGEXP_CAPTURE
    f.resize( 32 );
    nf = 0;
    cf = -1;
#endif
    realncap = 0;
    ncap = 0;
#ifndef QT_NO_REGEXP_CCLASS
    cl.setAutoDelete( TRUE );
#endif
#ifndef QT_NO_REGEXP_LOOKAHEAD
    ahead.setAutoDelete( TRUE );
#endif
#ifndef QT_NO_REGEXP_OPTIM
    caretAnchored = TRUE;
#endif
    valid = FALSE;
    cs = caseSensitive;
#ifndef QT_NO_REGEXP_BACKREF
    nbrefs = 0;
#endif
#ifndef QT_NO_REGEXP_OPTIM
    useGoodStringHeuristic = FALSE;
    minl = 0;
    occ1 = *firstOccurrenceAtZero;
#endif
    mmCapturedNoMatch.fill( -1, 2 );
}

int QRegExpEngine::setupState( int match )
{
    if ( (ns & (ns + 1)) == 0 && ns + 1 >= (int) s.size() )
    s.resize( (ns + 1) << 1 );
#ifndef QT_NO_REGEXP_CAPTURE
    s.insert( ns, new State(cf, match) );
#else
    s.insert( ns, new State(match) );
#endif
    return ns++;
}

#ifndef QT_NO_REGEXP_CAPTURE
/*
  Functions startAtom() and finishAtom() should be called to delimit atoms.
  When a state is created, it is assigned to the current atom.  The information
  is later used for capturing.
*/
int QRegExpEngine::startAtom( bool capture )
{
    if ( (nf & (nf + 1)) == 0 && nf + 1 >= (int) f.size() )
    f.resize( (nf + 1) << 1 );
    f[nf].parent = cf;
    cf = nf++;
    f[cf].capture = capture ? ncap++ : -1;
    return cf;
}
#endif

#ifndef QT_NO_REGEXP_LOOKAHEAD
/*
  Creates a lookahead anchor.
*/
int QRegExpEngine::addLookahead( QRegExpEngine *eng, bool negative )
{
    int n = ahead.size();
    if ( n == MaxLookaheads ) {
    yyError = TRUE;
    return 0;
    }
    ahead.resize( n + 1 );
    ahead.insert( n, new Lookahead(eng, negative) );
    return Anchor_FirstLookahead << n;
}
#endif

#ifndef QT_NO_REGEXP_CAPTURE
/*
  We want the longest leftmost captures.
*/
bool QRegExpEngine::isBetterCapture( const int *begin1, const int *end1,
                     const int *begin2, const int *end2 )
{
    for ( int i = 0; i < ncap; i++ ) {
    int delta = begin2[i] - begin1[i]; // it has to start early...
    if ( delta == 0 )
        delta = end1[i] - end2[i]; // ...and end late (like a party)

    if ( delta != 0 )
        return delta > 0;
    }
    return FALSE;
}
#endif

/*
  Returns TRUE if anchor a matches at position mmPos + i in the input string,
  otherwise FALSE.
*/
bool QRegExpEngine::testAnchor( int i, int a, const int *capBegin )
{
    int j;

#ifndef QT_NO_REGEXP_ANCHOR_ALT
    if ( (a & Anchor_Alternation) != 0 ) {
    return testAnchor( i, aa[a ^ Anchor_Alternation].a, capBegin ) ||
           testAnchor( i, aa[a ^ Anchor_Alternation].b, capBegin );
    }
#endif

    if ( (a & Anchor_Caret) != 0 ) {
    if ( mmPos + i != 0 )
        return FALSE;
    }
    if ( (a & Anchor_Dollar) != 0 ) {
    if ( mmPos + i != mmLen )
        return FALSE;
    }
#ifndef QT_NO_REGEXP_ESCAPE
    if ( (a & (Anchor_Word | Anchor_NonWord)) != 0 ) {
    bool before = FALSE, after = FALSE;
    if ( mmPos + i != 0 )
        before = mmIn[mmPos + i - 1].isLetterOrNumber();
    if ( mmPos + i != mmLen )
        after = mmIn[mmPos + i].isLetterOrNumber();
    if ( (a & Anchor_Word) != 0 && (before == after) )
        return FALSE;
    if ( (a & Anchor_NonWord) != 0 && (before != after) )
        return FALSE;
    }
#endif
#ifndef QT_NO_REGEXP_LOOKAHEAD
    bool catchx = TRUE;

    if ( (a & Anchor_LookaheadMask) != 0 ) {
    QConstString cstr = QConstString( (QChar *) mmIn + mmPos + i,
                       mmLen - mmPos - i );
    for ( j = 0; j < (int) ahead.size(); j++ ) {
        if ( (a & (Anchor_FirstLookahead << j)) != 0 ) {
        catchx = ( ahead[j]->eng->match(cstr.string(), 0, TRUE,
                        TRUE)[0] == 0 );
        if ( catchx == ahead[j]->neg )
            return FALSE;
        }
    }
    }
#endif
#ifndef QT_NO_REGEXP_CAPTURE
#ifndef QT_NO_REGEXP_BACKREF
    for ( j = 0; j < nbrefs; j++ ) {
    if ( (a & (Anchor_BackRef1Empty << j)) != 0 ) {
        if ( capBegin[j] != EmptyCapture )
        return FALSE;
    }
    }
#endif
#endif
    return TRUE;
}

#ifndef QT_NO_REGEXP_OPTIM
/*
  The three following functions are what Jeffrey Friedl would call transmissions
  (or bump-alongs).  Using one or the other should make no difference, except
  in performance.
*/

bool QRegExpEngine::goodStringMatch()
{
    int k = mmPos + goodEarlyStart;

    while ( (k = mmStr->find(goodStr, k, cs)) != -1 ) {
    int from = k - goodLateStart;
    int to = k - goodEarlyStart;
    if ( from > mmPos )
        mmPos = from;

    while ( mmPos <= to ) {
        if ( matchHere() )
        return TRUE;
        mmPos++;
    }
    k++;
    }
    return FALSE;
}

bool QRegExpEngine::badCharMatch()
{
    int slideHead = 0;
    int slideNext = 0;
    int i;
    int lastPos = mmLen - minl;
    memset( mmSlideTab, 0, mmSlideTabSize * sizeof(int) );

    /*
      Set up the slide table, used for the bad-character heuristic, using
      the table of first occurrence of each character.
    */
    for ( i = 0; i < minl; i++ ) {
    int sk = occ1[BadChar(mmIn[mmPos + i])];
    if ( sk == NoOccurrence )
        sk = i + 1;
    if ( sk > 0 ) {
        int k = i + 1 - sk;
        if ( k < 0 ) {
        sk = i + 1;
        k = 0;
        }
        if ( sk > mmSlideTab[k] )
        mmSlideTab[k] = sk;
    }
    }

    if ( mmPos > lastPos )
    return FALSE;

    while ( TRUE ) {
    if ( ++slideNext >= mmSlideTabSize )
        slideNext = 0;
    if ( mmSlideTab[slideHead] > 0 ) {
        if ( mmSlideTab[slideHead] - 1 > mmSlideTab[slideNext] )
        mmSlideTab[slideNext] = mmSlideTab[slideHead] - 1;
        mmSlideTab[slideHead] = 0;
    } else {
        if ( matchHere() )
        return TRUE;
    }

    if ( mmPos == lastPos )
        break;

    /*
      Update the slide table.  This code has much in common with the
      initialization code.
    */
    int sk = occ1[BadChar(mmIn[mmPos + minl])];
    if ( sk == NoOccurrence ) {
        mmSlideTab[slideNext] = minl;
    } else if ( sk > 0 ) {
        int k = slideNext + minl - sk;
        if ( k >= mmSlideTabSize )
        k -= mmSlideTabSize;
        if ( sk > mmSlideTab[k] )
        mmSlideTab[k] = sk;
    }
    slideHead = slideNext;
    mmPos++;
    }
    return FALSE;
}
#else
bool QRegExpEngine::bruteMatch()
{
    while ( mmPos <= mmLen ) {
    if ( matchHere() )
        return TRUE;
    mmPos++;
    }
    return FALSE;
}
#endif

/*
  Here's the core of the engine.  It tries to do a match here and now.
*/
bool QRegExpEngine::matchHere()
{
    int ncur = 1, nnext = 0;
    int i = 0, j, k, m;
    bool match = FALSE;

    mmMatchedLen = -1;
    mmCurStack[0] = InitialState;

#ifndef QT_NO_REGEXP_CAPTURE
    if ( ncap > 0 ) {
    for ( j = 0; j < ncap; j++ ) {
        mmCurCapBegin[j] = EmptyCapture;
        mmCurCapEnd[j] = EmptyCapture;
    }
    }
#endif

#ifndef QT_NO_REGEXP_BACKREF
    int *zzZ = 0;

    while ( (ncur > 0 || mmSleeping.count() > 0) && i <= mmLen - mmPos &&
        !match )
#else
    while ( ncur > 0 && i <= mmLen - mmPos && !match )
#endif
    {
    int ch = ( i < mmLen - mmPos ) ? mmIn[mmPos + i].unicode() : 0;
    for ( j = 0; j < ncur; j++ ) {
        int cur = mmCurStack[j];
        State *scur = s[cur];
        QArray<int>& outs = scur->outs;
        for ( k = 0; k < (int) outs.size(); k++ ) {
        int next = outs[k];
        State *snext = s[next];
        bool in = TRUE;
#ifndef QT_NO_REGEXP_BACKREF
        int needSomeSleep = 0;
#endif

        /*
          First, check if the anchors are anchored properly.
        */
        if ( scur->anchors != 0 ) {
            int a = at( *scur->anchors, next );
            if ( a != 0 && !testAnchor(i, a, mmCurCapBegin + j * ncap) )
            in = FALSE;
        }
        /*
          If indeed they are, check if the input character is correct
          for this transition.
        */
        if ( in ) {
            m = snext->match;
            if ( (m & (CharClassBit | BackRefBit)) == 0 ) {
            if ( cs )
                in = ( m == ch );
            else
                in = ( QChar(m).lower() == QChar(ch).lower() );
            } else if ( next == FinalState ) {
            mmMatchedLen = i;
            match = mmMinimal;
            in = TRUE;
            } else if ( (m & CharClassBit) != 0 ) {
#ifndef QT_NO_REGEXP_CCLASS
            const CharClass *cc = cl[m ^ CharClassBit];
            if ( cs )
                in = cc->in( ch );
            else if ( cc->negative() )
                in = cc->in( QChar(ch).lower() ) &&
                 cc->in( QChar(ch).upper() );
            else
                in = cc->in( QChar(ch).lower() ) ||
                 cc->in( QChar(ch).upper() );
#endif
#ifndef QT_NO_REGEXP_BACKREF
            } else { /* ( (m & BackRefBit) != 0 ) */
            int bref = m ^ BackRefBit;
            int ell = j * ncap + ( bref - 1 );

            in = bref <= ncap && mmCurCapBegin[ell] != EmptyCapture;
            if ( in ) {
                if ( cs )
                in = ( mmIn[mmPos + mmCurCapBegin[ell]]
                       == QChar(ch) );
                else
                in = ( mmIn[mmPos + mmCurCapBegin[ell]].lower()
                       == QChar(ch).lower() );
            }

            if ( in ) {
                int delta;
                if ( mmCurCapEnd[ell] == EmptyCapture )
                delta = i - mmCurCapBegin[ell];
                else
                delta = mmCurCapEnd[ell] - mmCurCapBegin[ell];

                in = ( delta <= mmLen - mmPos );
                if ( in && delta > 1 ) {
                int n;
                if ( cs ) {
                    for ( n = 1; n < delta; n++ ) {
                    if ( mmIn[mmPos +
                          mmCurCapBegin[ell] + n] !=
                         mmIn[mmPos + i + n] )
                        break;
                    }
                } else {
                    for ( n = 1; n < delta; n++ ) {
                    QChar a = mmIn[mmPos +
                               mmCurCapBegin[ell] + n];
                    QChar b = mmIn[mmPos + i + n];
                    if ( a.lower() != b.lower() )
                        break;
                    }
                }
                in = ( n == delta );
                if ( in )
                    needSomeSleep = delta - 1;
                }
            }
#endif
            }
        }

        /*
          All is right.  We must now update our data structures.
        */
        if ( in ) {
#ifndef QT_NO_REGEXP_CAPTURE
            int *capBegin, *capEnd;
#endif
            /*
              If the next state was not encountered yet, all is fine.
            */
            if ( (m = mmInNextStack[next]) == -1 ) {
            m = nnext++;
            mmNextStack[m] = next;
            mmInNextStack[next] = m;
#ifndef QT_NO_REGEXP_CAPTURE
            capBegin = mmNextCapBegin + m * ncap;
            capEnd = mmNextCapEnd + m * ncap;

            /*
              Otherwise, we'll first maintain captures in temporary
              arrays, and decide at the end whether it's best to keep
              the previous capture zones or the new ones.
            */
            } else {
            capBegin = mmTempCapBegin;
            capEnd = mmTempCapEnd;
#endif
            }

#ifndef QT_NO_REGEXP_CAPTURE
            /*
              Updating the capture zones is much of a task.
            */
            if ( ncap > 0 ) {
            memcpy( capBegin, mmCurCapBegin + j * ncap,
                ncap * sizeof(int) );
            memcpy( capEnd, mmCurCapEnd + j * ncap,
                ncap * sizeof(int) );
            int c = scur->atom, n = snext->atom;
            int p = -1, q = -1;
            int cap;

            /*
              Lemma 1.  For any x in the range [0..nf), we have
              f[x].parent < x.

              Proof.  By looking at startAtom(), it is clear that
              cf < nf holds all the time, and thus that
              f[nf].parent < nf.
            */

            /*
              If we are reentering an atom, we empty all capture
              zones inside it.
            */
            if ( scur->reenter != 0 &&
                 (q = at(*scur->reenter, next)) != 0 ) {
                QBitArray b;
                b.fill( FALSE, nf );
                b.setBit( q, TRUE );
                for ( int ell = q + 1; ell < nf; ell++ ) {
                if ( b.testBit(f[ell].parent) ) {
                    b.setBit( ell, TRUE );
                    cap = f[ell].capture;
                    if ( cap >= 0 ) {
                    capBegin[cap] = EmptyCapture;
                    capEnd[cap] = EmptyCapture;
                    }
                }
                }
                p = f[q].parent;

            /*
              Otherwise, close the capture zones we are leaving.
              We are leaving f[c].capture, f[f[c].parent].capture,
              f[f[f[c].parent].parent].capture, ..., until
              f[x].capture, with x such that f[x].parent is the
              youngest common ancestor for c and n.

              We go up along c's and n's ancestry until we find x.
            */
            } else {
                p = c;
                q = n;
                while ( p != q ) {
                if ( p > q ) {
                    cap = f[p].capture;
                    if ( cap >= 0 ) {
                    if ( capBegin[cap] == i ) {
                        capBegin[cap] = EmptyCapture;
                        capEnd[cap] = EmptyCapture;
                    } else {
                        capEnd[cap] = i;
                    }
                    }
                    p = f[p].parent;
                } else {
                    q = f[q].parent;
                }
                }
            }

            /*
              In any case, we now open the capture zones we are
              entering.  We work upwards from n until we reach p
              (the parent of the atom we reenter or the youngest
              common ancestor).
            */
            while ( n > p ) {
                cap = f[n].capture;
                if ( cap >= 0 ) {
                capBegin[cap] = i;
                capEnd[cap] = EmptyCapture;
                }
                n = f[n].parent;
            }
            /*
              If the next state was already in mmNextStack, we must
              choose carefully which capture zones we want to keep.
            */
            if ( capBegin == mmTempCapBegin &&
                 isBetterCapture(capBegin, capEnd,
                         mmNextCapBegin + m * ncap,
                         mmNextCapEnd + m * ncap) ) {
                memcpy( mmNextCapBegin + m * ncap, capBegin,
                    ncap * sizeof(int) );
                memcpy( mmNextCapEnd + m * ncap, capEnd,
                    ncap * sizeof(int) );
            }
            }
#ifndef QT_NO_REGEXP_BACKREF
            /*
              We are done with updating the capture zones.  It's now
              time to put the next state to sleep, if it needs to, and
              to remove it from mmNextStack.
            */
            if ( needSomeSleep > 0 ) {
            zzZ = new int[1 + 2 * ncap];
            zzZ[0] = next;
            if ( ncap > 0 ) {
                memcpy( zzZ + 1, capBegin, ncap * sizeof(int) );
                memcpy( zzZ + 1 + ncap, capEnd,
                    ncap * sizeof(int) );
            }
            mmInNextStack[mmNextStack[--nnext]] = -1;
            mmSleeping.insert( i + needSomeSleep, zzZ );
            }
#endif
#endif
        }
        }
    }
#ifndef QT_NO_REGEXP_CAPTURE
    /*
      If we reached the final state, hurray!  Copy the captured zone.
    */
    if ( ncap > 0 && (m = mmInNextStack[FinalState]) != -1 ) {
        memcpy( mmCapBegin, mmNextCapBegin + m * ncap, ncap * sizeof(int) );
        memcpy( mmCapEnd, mmNextCapEnd + m * ncap, ncap * sizeof(int) );
    }
#ifndef QT_NO_REGEXP_BACKREF
    /*
      It's time to wake up the sleepers.
    */
    if ( mmSleeping.count() > 0 ) {
        while ( (zzZ = mmSleeping.take(i)) != 0 ) {
        int next = zzZ[0];
        int *capBegin = zzZ + 1;
        int *capEnd = zzZ + 1 + ncap;
        bool copyOver = TRUE;

        if ( (m = mmInNextStack[zzZ[0]]) == -1 ) {
            m = nnext++;
            mmNextStack[m] = next;
            mmInNextStack[next] = m;
        } else {
            copyOver = isBetterCapture( mmNextCapBegin + m * ncap,
                        mmNextCapEnd + m * ncap,
                        capBegin, capEnd );
        }
        if ( copyOver ) {
            memcpy( mmNextCapBegin + m * ncap, capBegin,
                ncap * sizeof(int) );
            memcpy( mmNextCapEnd + m * ncap, capEnd,
                ncap * sizeof(int) );
        }
        delete[] zzZ;
        }
    }
#endif
#endif
    for ( j = 0; j < nnext; j++ )
        mmInNextStack[mmNextStack[j]] = -1;

    qSwap( mmCurStack, mmNextStack );
#ifndef QT_NO_REGEXP_CAPTURE
    qSwap( mmCurCapBegin, mmNextCapBegin );
    qSwap( mmCurCapEnd, mmNextCapEnd );
#endif
    ncur = nnext;
    nnext = 0;
    i++;
    }

#ifndef QT_NO_REGEXP_BACKREF
    /*
      If minimal matching is enabled, we might have some sleepers left.
    */
    while ( !mmSleeping.isEmpty() ) {
    zzZ = mmSleeping.take( *QIntDictIterator<int>(mmSleeping) );
    delete[] zzZ;
    }
#endif

    match = ( mmMatchedLen >= 0 );
    if ( !match )
    mmMatchedLen = i - 1;
    return match;
}

#ifndef QT_NO_REGEXP_CCLASS

QRegExpEngine::CharClass::CharClass()
    : c( 0 ), n( FALSE )
#ifndef QT_NO_REGEXP_OPTIM
      , occ1( *noOccurrences )
#endif
{
}

QRegExpEngine::CharClass& QRegExpEngine::CharClass::operator=(
    const CharClass& cc )
{
    c = cc.c;
    r = cc.r.copy();
    n = cc.n;
#ifndef QT_NO_REGEXP_OPTIM
    occ1 = cc.occ1;
#endif
    return *this;
}

void QRegExpEngine::CharClass::clear()
{
    c = 0;
    r.resize( 0 );
    n = FALSE;
}

void QRegExpEngine::CharClass::setNegative( bool negative )
{
    n = negative;
#ifndef QT_NO_REGEXP_OPTIM
    occ1 = *firstOccurrenceAtZero;
#endif
}

void QRegExpEngine::CharClass::addCategories( int cats )
{
    c |= cats;
#ifndef QT_NO_REGEXP_OPTIM
    occ1 = *firstOccurrenceAtZero;
#endif
}

void QRegExpEngine::CharClass::addRange( ushort from, ushort to )
{
    if ( from > to )
    qSwap( from, to );
    int n = r.size();
    r.resize( n + 1 );
    r[n].from = from;
    r[n].to = to;

#ifndef QT_NO_REGEXP_OPTIM
    int i;

    if ( to - from < NumBadChars ) {
    occ1.detach();
    if ( from % NumBadChars <= to % NumBadChars ) {
        for ( i = from % NumBadChars; i <= to % NumBadChars; i++ )
        occ1[i] = 0;
    } else {
        for ( i = 0; i <= to % NumBadChars; i++ )
        occ1[i] = 0;
        for ( i = from % NumBadChars; i < NumBadChars; i++ )
        occ1[i] = 0;
    }
    } else {
    occ1 = *firstOccurrenceAtZero;
    }
#endif
}

bool QRegExpEngine::CharClass::in( QChar ch ) const
{
#ifndef QT_NO_REGEXP_OPTIM
    if ( occ1[BadChar(ch)] == NoOccurrence )
    return n;
#endif

    if ( c != 0 && (c & (1 << (int) ch.category())) != 0 )
    return !n;
    for ( int i = 0; i < (int) r.size(); i++ ) {
    if ( ch.unicode() >= r[i].from && ch.unicode() <= r[i].to )
        return !n;
    }
    return n;
}

#if defined(QT_DEBUG)
void QRegExpEngine::CharClass::dump() const
{
    int i;
    odebug << "    " << (n ? "nega" : "posi") << "tive character class" << oendl;
#ifndef QT_NO_REGEXP_CCLASS
    if ( c != 0 )
    odebug << QString().sprintf("      categories 0x%.8x", c ) << oendl;
#endif
    for ( i = 0; i < (int) r.size(); i++ )
    odebug << QString().sprintf("      0x%.4x through 0x%.4x", r[i].from, r[i].to ) << oendl;
}
#endif
#endif

QRegExpEngine::Box::Box( QRegExpEngine *engine )
    : eng( engine ), skipanchors( 0 )
#ifndef QT_NO_REGEXP_OPTIM
      , earlyStart( 0 ), lateStart( 0 ), maxl( 0 ), occ1( *noOccurrences )
#endif
{
    minl = 0;
}

QRegExpEngine::Box& QRegExpEngine::Box::operator=( const Box& b )
{
    eng = b.eng;
    ls = b.ls;
    rs = b.rs;
    lanchors = b.lanchors;
    ranchors = b.ranchors;
    skipanchors = b.skipanchors;
#ifndef QT_NO_REGEXP_OPTIM
    earlyStart = b.earlyStart;
    lateStart = b.lateStart;
    str = b.str;
    leftStr = b.leftStr;
    rightStr = b.rightStr;
    maxl = b.maxl;
    occ1 = b.occ1;
#endif
    minl = b.minl;
    return *this;
}

void QRegExpEngine::Box::set( QChar ch )
{
    ls.resize( 1 );
    ls[0] = eng->createState( ch );
    rs = ls;
    rs.detach();
#ifndef QT_NO_REGEXP_OPTIM
    str = ch;
    leftStr = ch;
    rightStr = ch;
    maxl = 1;
    occ1.detach();
    occ1[BadChar(ch)] = 0;
#endif
    minl = 1;
}

void QRegExpEngine::Box::set( const CharClass& cc )
{
    ls.resize( 1 );
    ls[0] = eng->createState( cc );
    rs = ls;
    rs.detach();
#ifndef QT_NO_REGEXP_OPTIM
    maxl = 1;
    occ1 = cc.firstOccurrence();
#endif
    minl = 1;
}

#ifndef QT_NO_REGEXP_BACKREF
void QRegExpEngine::Box::set( int bref )
{
    ls.resize( 1 );
    ls[0] = eng->createState( bref );
    rs = ls;
    rs.detach();
    if ( bref >= 1 && bref <= MaxBackRefs )
    skipanchors = Anchor_BackRef0Empty << bref;
#ifndef QT_NO_REGEXP_OPTIM
    maxl = InftyLen;
#endif
    minl = 0;
}
#endif

void QRegExpEngine::Box::cat( const Box& b )
{
    eng->addCatTransitions( rs, b.ls );
    addAnchorsToEngine( b );
    if ( minl == 0 ) {
    mergeInto( &lanchors, b.lanchors );
    if ( skipanchors != 0 ) {
        for ( int i = 0; i < (int) b.ls.size(); i++ ) {
        int a = eng->anchorConcatenation( at(lanchors, b.ls[i]),
                          skipanchors );
        lanchors.insert( b.ls[i], a );
        }
    }
    mergeInto( &ls, b.ls );
    }
    if ( b.minl == 0 ) {
    mergeInto( &ranchors, b.ranchors );
    if ( b.skipanchors != 0 ) {
        for ( int i = 0; i < (int) rs.size(); i++ ) {
        int a = eng->anchorConcatenation( at(ranchors, rs[i]),
                          b.skipanchors );
        ranchors.insert( rs[i], a );
        }
    }
    mergeInto( &rs, b.rs );
    } else {
    ranchors = b.ranchors;
    rs = b.rs;
    }

#ifndef QT_NO_REGEXP_OPTIM
    if ( maxl != InftyLen ) {
    if ( rightStr.length() + b.leftStr.length() >
         QMAX(str.length(), b.str.length()) ) {
        earlyStart = minl - rightStr.length();
        lateStart = maxl - rightStr.length();
        str = rightStr + b.leftStr;
    } else if ( b.str.length() > str.length() ) {
        earlyStart = minl + b.earlyStart;
        lateStart = maxl + b.lateStart;
        str = b.str;
    }
    }

    if ( (int) leftStr.length() == maxl )
    leftStr += b.leftStr;
    if ( (int) b.rightStr.length() == b.maxl )
    rightStr += b.rightStr;
    else
    rightStr = b.rightStr;

    if ( maxl == InftyLen || b.maxl == InftyLen )
    maxl = InftyLen;
    else
    maxl += b.maxl;

    occ1.detach();
    for ( int i = 0; i < NumBadChars; i++ ) {
    if ( b.occ1[i] != NoOccurrence && minl + b.occ1[i] < occ1[i] )
        occ1[i] = minl + b.occ1[i];
    }
#endif

    minl += b.minl;
    if ( minl == 0 )
    skipanchors = eng->anchorConcatenation( skipanchors, b.skipanchors );
    else
    skipanchors = 0;
}

void QRegExpEngine::Box::orx( const Box& b )
{
    mergeInto( &ls, b.ls );
    mergeInto( &lanchors, b.lanchors );
    mergeInto( &rs, b.rs );
    mergeInto( &ranchors, b.ranchors );
    skipanchors = eng->anchorAlternation( skipanchors, b.skipanchors );

#ifndef QT_NO_REGEXP_OPTIM
    occ1.detach();
    for ( int i = 0; i < NumBadChars; i++ ) {
    if ( occ1[i] > b.occ1[i] )
        occ1[i] = b.occ1[i];
    }
    earlyStart = 0;
    lateStart = 0;
    str = QString::null;
    leftStr = QString::null;
    rightStr = QString::null;
    if ( b.maxl > maxl )
    maxl = b.maxl;
#endif
    if ( b.minl < minl )
    minl = b.minl;
}

void QRegExpEngine::Box::plus( int atom )
{
#ifndef QT_NO_REGEXP_CAPTURE
    eng->addPlusTransitions( rs, ls, atom );
#else
    Q_UNUSED( atom );
    eng->addCatTransitions( rs, ls );
#endif
    addAnchorsToEngine( *this );
#ifndef QT_NO_REGEXP_OPTIM
    maxl = InftyLen;
#endif
}

void QRegExpEngine::Box::opt()
{
#ifndef QT_NO_REGEXP_OPTIM
    earlyStart = 0;
    lateStart = 0;
    str = QString::null;
    leftStr = QString::null;
    rightStr = QString::null;
#endif
    skipanchors = 0;
    minl = 0;
}

void QRegExpEngine::Box::catAnchor( int a )
{
    if ( a != 0 ) {
    for ( int i = 0; i < (int) rs.size(); i++ ) {
        a = eng->anchorConcatenation( at(ranchors, rs[i]), a );
        ranchors.insert( rs[i], a );
    }
    if ( minl == 0 )
        skipanchors = eng->anchorConcatenation( skipanchors, a );
    }
}

#ifndef QT_NO_REGEXP_OPTIM
void QRegExpEngine::Box::setupHeuristics()
{
    eng->setupGoodStringHeuristic( earlyStart, lateStart, str );

    /*
      A regular expression such as 112|1 has occ1['2'] = 2 and minl = 1 at this
      point.  An entry of occ1 has to be at most minl or infinity for the rest
      of the algorithm to go well.

      We waited until here before normalizing these cases (instead of doing it
      in Box::orx()) because sometimes things improve by themselves; consider
      (112|1)34.
    */
    for ( int i = 0; i < NumBadChars; i++ ) {
    if ( occ1[i] != NoOccurrence && occ1[i] >= minl )
        occ1[i] = minl;
    }
    eng->setupBadCharHeuristic( minl, occ1 );

    eng->heuristicallyChooseHeuristic();
}
#endif

#if defined(QT_DEBUG)
void QRegExpEngine::Box::dump() const
{
    int i;
    odebug << "Box of at least " << minl << " character" << (minl == 1 ? "" : "s") << oendl;
    odebug << "  Left states:" << oendl;
    for ( i = 0; i < (int) ls.size(); i++ ) {
    if ( at(lanchors, ls[i]) == 0 )
        odebug << "    " << ls[i] << oendl;
    else
        odebug << "    " << ls[i] << QString().sprintf(" [anchors 0x%.8x]", lanchors[ls[i]]) << oendl;
    }
    odebug << "  Right states:" << oendl;
    for ( i = 0; i < (int) rs.size(); i++ ) {
    if ( at(ranchors, ls[i]) == 0 )
        odebug << "    " << rs[i] << oendl;
    else
        odebug << "    " << rs[i] << QString().sprintf(" [anchors 0x%.8x]", ranchors[rs[i]]) << oendl;
    }
    odebug << QString().sprintf("  Skip anchors: 0x%.8x", skipanchors) << oendl;
}
#endif

void QRegExpEngine::Box::addAnchorsToEngine( const Box& to ) const
{
    for ( int i = 0; i < (int) to.ls.size(); i++ ) {
    for ( int j = 0; j < (int) rs.size(); j++ ) {
        int a = eng->anchorConcatenation( at(ranchors, rs[j]),
                          at(to.lanchors, to.ls[i]) );
        eng->addAnchors( rs[j], to.ls[i], a );
    }
    }
}

int QRegExpEngine::getChar()
{
    return ( yyPos == yyLen ) ? EOS : yyIn[yyPos++].unicode();
}

int QRegExpEngine::getEscape()
{
#ifndef QT_NO_REGEXP_ESCAPE
    const char tab[] = "afnrtv"; // no b, as \b means word boundary
    const char backTab[] = "\a\f\n\r\t\v";
    ushort low;
    int i;
#endif
    ushort val;
    int prevCh = yyCh;

    if ( prevCh == EOS ) {
    yyError = TRUE;
    return Tok_Char | '\\';
    }
    yyCh = getChar();
#ifndef QT_NO_REGEXP_ESCAPE
    if ( (prevCh & ~0xff) == 0 ) {
    const char *p = strchr( tab, prevCh );
    if ( p != 0 )
        return Tok_Char | backTab[p - tab];
    }
#endif

    switch ( prevCh ) {
#ifndef QT_NO_REGEXP_ESCAPE
    case '0':
    val = 0;
    for ( i = 0; i < 3; i++ ) {
        if ( yyCh >= '0' && yyCh <= '7' )
        val = ( val << 3 ) | ( yyCh - '0' );
        else
        break;
        yyCh = getChar();
    }
    if ( (val & ~0377) != 0 )
        yyError = TRUE;
    return Tok_Char | val;
#endif
#ifndef QT_NO_REGEXP_ESCAPE
    case 'B':
    return Tok_NonWord;
#endif
#ifndef QT_NO_REGEXP_CCLASS
    case 'D':
    // see QChar::isDigit()
    yyCharClass->addCategories( 0x7fffffef );
    return Tok_CharClass;
    case 'S':
    // see QChar::isSpace()
    yyCharClass->addCategories( 0x7ffff87f );
    yyCharClass->addRange( 0x0000, 0x0008 );
    yyCharClass->addRange( 0x000e, 0x001f );
    yyCharClass->addRange( 0x007f, 0x009f );
    return Tok_CharClass;
    case 'W':
    // see QChar::isLetterOrNumber()
    yyCharClass->addCategories( 0x7ff07f8f );
    return Tok_CharClass;
#endif
#ifndef QT_NO_REGEXP_ESCAPE
    case 'b':
    return Tok_Word;
#endif
#ifndef QT_NO_REGEXP_CCLASS
    case 'd':
    // see QChar::isDigit()
    yyCharClass->addCategories( 0x00000010 );
    return Tok_CharClass;
    case 's':
    // see QChar::isSpace()
    yyCharClass->addCategories( 0x00000380 );
    yyCharClass->addRange( 0x0009, 0x000d );
    return Tok_CharClass;
    case 'w':
    // see QChar::isLetterOrNumber()
    yyCharClass->addCategories( 0x000f8070 );
    return Tok_CharClass;
#endif
#ifndef QT_NO_REGEXP_ESCAPE
    case 'x':
    val = 0;
    for ( i = 0; i < 4; i++ ) {
        low = QChar( yyCh ).lower();
        if ( low >= '0' && low <= '9' )
        val = ( val << 4 ) | ( low - '0' );
        else if ( low >= 'a' && low <= 'f' )
        val = ( val << 4 ) | ( low - 'a' + 10 );
        else
        break;
        yyCh = getChar();
    }
    return Tok_Char | val;
#endif
    default:
    if ( prevCh >= '1' && prevCh <= '9' ) {
#ifndef QT_NO_REGEXP_BACKREF
        val = prevCh - '0';
        while ( yyCh >= '0' && yyCh <= '9' ) {
        val = ( val *= 10 ) | ( yyCh - '0' );
        yyCh = getChar();
        }
        return Tok_BackRef | val;
#else
        yyError = TRUE;
#endif
    }
    return Tok_Char | prevCh;
    }
}

#ifndef QT_NO_REGEXP_INTERVAL
int QRegExpEngine::getRep( int def )
{
    if ( yyCh >= '0' && yyCh <= '9' ) {
    int rep = 0;
    do {
        rep = 10 * rep + yyCh - '0';
        if ( rep >= InftyRep ) {
        yyError = TRUE;
        rep = def;
        }
        yyCh = getChar();
    } while ( yyCh >= '0' && yyCh <= '9' );
    return rep;
    } else {
    return def;
    }
}
#endif

#ifndef QT_NO_REGEXP_LOOKAHEAD
void QRegExpEngine::skipChars( int n )
{
    if ( n > 0 ) {
    yyPos += n - 1;
    yyCh = getChar();
    }
}
#endif

void QRegExpEngine::startTokenizer( const QChar *rx, int len )
{
    yyIn = rx;
    yyPos0 = 0;
    yyPos = 0;
    yyLen = len;
    yyCh = getChar();
    yyCharClass = new CharClass;
    yyMinRep = 0;
    yyMaxRep = 0;
    yyError = FALSE;
}

int QRegExpEngine::getToken()
{
#ifndef QT_NO_REGEXP_CCLASS
    ushort pendingCh = 0;
    bool charPending;
    bool rangePending;
    int tok;
#endif
    int prevCh = yyCh;

    yyPos0 = yyPos - 1;
#ifndef QT_NO_REGEXP_CCLASS
    yyCharClass->clear();
#endif
    yyMinRep = 0;
    yyMaxRep = 0;
    yyCh = getChar();
    switch ( prevCh ) {
    case EOS:
    yyPos0 = yyPos;
    return Tok_Eos;
    case '$':
    return Tok_Dollar;
    case '(':
    if ( yyCh == '?' ) {
        prevCh = getChar();
        yyCh = getChar();
        switch ( prevCh ) {
#ifndef QT_NO_REGEXP_LOOKAHEAD
        case '!':
        return Tok_NegLookahead;
        case '=':
        return Tok_PosLookahead;
#endif
        case ':':
        return Tok_MagicLeftParen;
        default:
        yyError = TRUE;
        return Tok_MagicLeftParen;
        }
    } else {
        return Tok_LeftParen;
    }
    case ')':
    return Tok_RightParen;
    case '*':
    yyMinRep = 0;
    yyMaxRep = InftyRep;
    return Tok_Quantifier;
    case '+':
    yyMinRep = 1;
    yyMaxRep = InftyRep;
    return Tok_Quantifier;
    case '.':
#ifndef QT_NO_REGEXP_CCLASS
    yyCharClass->setNegative( TRUE );
#endif
    return Tok_CharClass;
    case '?':
    yyMinRep = 0;
    yyMaxRep = 1;
    return Tok_Quantifier;
    case '[':
#ifndef QT_NO_REGEXP_CCLASS
    if ( yyCh == '^' ) {
        yyCharClass->setNegative( TRUE );
        yyCh = getChar();
    }
    charPending = FALSE;
    rangePending = FALSE;
    do {
        if ( yyCh == '-' && charPending && !rangePending ) {
        rangePending = TRUE;
        yyCh = getChar();
        } else {
        if ( charPending && !rangePending ) {
            yyCharClass->addSingleton( pendingCh );
            charPending = FALSE;
        }
        if ( yyCh == '\\' ) {
            yyCh = getChar();
            tok = getEscape();
            if ( tok == Tok_Word )
            tok = '\b';
        } else {
            tok = Tok_Char | yyCh;
            yyCh = getChar();
        }
        if ( tok == Tok_CharClass ) {
            if ( rangePending ) {
            yyCharClass->addSingleton( '-' );
            yyCharClass->addSingleton( pendingCh );
            charPending = FALSE;
            rangePending = FALSE;
            }
        } else if ( (tok & Tok_Char) != 0 ) {
            if ( rangePending ) {
            yyCharClass->addRange( pendingCh, tok ^ Tok_Char );
            charPending = FALSE;
            rangePending = FALSE;
            } else {
            pendingCh = tok ^ Tok_Char;
            charPending = TRUE;
            }
        } else {
            yyError = TRUE;
        }
        }
    }  while ( yyCh != ']' && yyCh != EOS );
    if ( rangePending )
        yyCharClass->addSingleton( '-' );
    if ( charPending )
        yyCharClass->addSingleton( pendingCh );
    if ( yyCh == EOS )
        yyError = TRUE;
    else
        yyCh = getChar();
    return Tok_CharClass;
#else
    yyError = TRUE;
    return Tok_Char | '[';
#endif
    case '\\':
    return getEscape();
    case ']':
    yyError = TRUE;
    return Tok_Char | ']';
    case '^':
    return Tok_Caret;
#ifndef QT_NO_REGEXP_INTERVAL
    case '{':
    yyMinRep = getRep( 0 );
    yyMaxRep = yyMinRep;
    if ( yyCh == ',' ) {
        yyCh = getChar();
        yyMaxRep = getRep( InftyRep );
    }
    if ( yyMaxRep < yyMinRep )
        qSwap( yyMinRep, yyMaxRep );
    if ( yyCh != '}' )
        yyError = TRUE;
    yyCh = getChar();
    return Tok_Quantifier;
#else
    yyError = TRUE;
    return Tok_Char | '{';
#endif
    case '|':
    return Tok_Bar;
    case '}':
    yyError = TRUE;
    return Tok_Char | '}';
    default:
    return Tok_Char | prevCh;
    }
}

int QRegExpEngine::parse( const QChar *pattern, int len )
{
    valid = TRUE;
    startTokenizer( pattern, len );
    yyTok = getToken();
#ifndef QT_NO_REGEXP_CAPTURE
    yyMayCapture = TRUE;
#else
    yyMayCapture = FALSE;
#endif

#ifndef QT_NO_REGEXP_CAPTURE
    int atom = startAtom( FALSE );
#endif
    CharClass anything;
    Box box( this ); // create InitialState
    box.set( anything );
    Box rightBox( this ); // create FinalState
    rightBox.set( anything );

    Box middleBox( this );
    parseExpression( &middleBox );
#ifndef QT_NO_REGEXP_CAPTURE
    finishAtom( atom );
#endif
#ifndef QT_NO_REGEXP_OPTIM
    middleBox.setupHeuristics();
#endif
    box.cat( middleBox );
    box.cat( rightBox );
    delete yyCharClass;
    yyCharClass = 0;

    realncap = ncap;
#ifndef QT_NO_REGEXP_BACKREF
    if ( nbrefs > ncap )
    ncap = nbrefs;
#endif

    mmCaptured.resize( 2 + 2 * realncap );
    mmCapturedNoMatch.fill( -1, 2 + 2 * realncap );

    /*
      We use one QArray<int> for all the big data used a lot in matchHere() and
      friends.
    */
#ifndef QT_NO_REGEXP_OPTIM
    mmSlideTabSize = QMAX( minl + 1, 16 );
#else
    mmSlideTabSize = 0;
#endif
    mmBigArray.resize( (3 + 4 * ncap) * ns + 4 * ncap + mmSlideTabSize );

    mmInNextStack = mmBigArray.data();
    memset( mmInNextStack, -1, ns * sizeof(int) );
    mmCurStack = mmInNextStack + ns;
    mmNextStack = mmInNextStack + 2 * ns;

    mmCurCapBegin = mmInNextStack + 3 * ns;
    mmNextCapBegin = mmCurCapBegin + ncap * ns;
    mmCurCapEnd = mmCurCapBegin + 2 * ncap * ns;
    mmNextCapEnd = mmCurCapBegin + 3 * ncap * ns;

    mmTempCapBegin = mmCurCapBegin + 4 * ncap * ns;
    mmTempCapEnd = mmTempCapBegin + ncap;
    mmCapBegin = mmTempCapBegin + 2 * ncap;
    mmCapEnd = mmTempCapBegin + 3 * ncap;

    mmSlideTab = mmTempCapBegin + 4 * ncap;

    if ( yyError )
    return -1;

#ifndef QT_NO_REGEXP_OPTIM
    State *sinit = s[InitialState];
    caretAnchored = ( sinit->anchors != 0 );
    if ( caretAnchored ) {
    QMap<int, int>& anchors = *sinit->anchors;
    QMap<int, int>::ConstIterator a;
    for ( a = anchors.begin(); a != anchors.end(); ++a ) {
#ifndef QT_NO_REGEXP_ANCHOR_ALT
        if ( (*a & Anchor_Alternation) != 0 )
        break;
#endif
        if ( (*a & Anchor_Caret) == 0 ) {
        caretAnchored = FALSE;
        break;
        }
    }
    }
#endif
    return yyPos0;
}

void QRegExpEngine::parseAtom( Box *box )
{
#ifndef QT_NO_REGEXP_LOOKAHEAD
    QRegExpEngine *eng = 0;
    bool neg;
    int len;
#endif

    switch ( yyTok ) {
    case Tok_Dollar:
    box->catAnchor( Anchor_Dollar );
    break;
    case Tok_Caret:
    box->catAnchor( Anchor_Caret );
    break;
#ifndef QT_NO_REGEXP_LOOKAHEAD
    case Tok_PosLookahead:
    case Tok_NegLookahead:
    neg = ( yyTok == Tok_NegLookahead );
    eng = new QRegExpEngine( cs );
    len = eng->parse( yyIn + yyPos - 1, yyLen - yyPos + 1 );
    if ( len >= 0 )
        skipChars( len );
    else
        yyError = TRUE;
    box->catAnchor( addLookahead(eng, neg) );
    yyTok = getToken();
    if ( yyTok != Tok_RightParen )
        yyError = TRUE;
    break;
#endif
#ifndef QT_NO_REGEXP_ESCAPE
    case Tok_Word:
    box->catAnchor( Anchor_Word );
    break;
    case Tok_NonWord:
    box->catAnchor( Anchor_NonWord );
    break;
#endif
    case Tok_LeftParen:
    case Tok_MagicLeftParen:
    yyTok = getToken();
    parseExpression( box );
    if ( yyTok != Tok_RightParen )
        yyError = TRUE;
    break;
    case Tok_CharClass:
    box->set( *yyCharClass );
    break;
    default:
    if ( (yyTok & Tok_Char) != 0 )
        box->set( QChar(yyTok ^ Tok_Char) );
#ifndef QT_NO_REGEXP_BACKREF
    else if ( (yyTok & Tok_BackRef) != 0 )
        box->set( yyTok ^ Tok_BackRef );
#endif
    else
        yyError = TRUE;
    }
    yyTok = getToken();
}

void QRegExpEngine::parseFactor( Box *box )
{
#ifndef QT_NO_REGEXP_CAPTURE
    int atom = startAtom( yyMayCapture && yyTok == Tok_LeftParen );
#else
    static const int atom = 0;
#endif

#ifndef QT_NO_REGEXP_INTERVAL
#define YYREDO() \
    yyIn = in, yyPos0 = pos0, yyPos = pos, yyLen = len, yyCh = ch, \
    *yyCharClass = charClass, yyMinRep = 0, yyMaxRep = 0, yyTok = tok

    const QChar *in = yyIn;
    int pos0 = yyPos0;
    int pos = yyPos;
    int len = yyLen;
    int ch = yyCh;
    CharClass charClass;
    if ( yyTok == Tok_CharClass )
    charClass = *yyCharClass;
    int tok = yyTok;
    bool mayCapture = yyMayCapture;
#endif

    parseAtom( box );
#ifndef QT_NO_REGEXP_CAPTURE
    finishAtom( atom );
#endif

    if ( yyTok == Tok_Quantifier ) {
    if ( yyMaxRep == InftyRep ) {
        box->plus( atom );
#ifndef QT_NO_REGEXP_INTERVAL
    } else if ( yyMaxRep == 0 ) {
        box->clear();
#endif
    }
    if ( yyMinRep == 0 )
        box->opt();

#ifndef QT_NO_REGEXP_INTERVAL
    yyMayCapture = FALSE;
    int alpha = ( yyMinRep == 0 ) ? 0 : yyMinRep - 1;
    int beta = ( yyMaxRep == InftyRep ) ? 0 : yyMaxRep - ( alpha + 1 );

    Box rightBox( this );
    int i;

    for ( i = 0; i < beta; i++ ) {
        YYREDO();
        Box leftBox( this );
        parseAtom( &leftBox );
        leftBox.cat( rightBox );
        leftBox.opt();
        rightBox = leftBox;
    }
    for ( i = 0; i < alpha; i++ ) {
        YYREDO();
        Box leftBox( this );
        parseAtom( &leftBox );
        leftBox.cat( rightBox );
        rightBox = leftBox;
    }
    rightBox.cat( *box );
    *box = rightBox;
#endif
    yyTok = getToken();
#ifndef QT_NO_REGEXP_INTERVAL
    yyMayCapture = mayCapture;
#endif
    }
#undef YYREDO
}

void QRegExpEngine::parseTerm( Box *box )
{
#ifndef QT_NO_REGEXP_OPTIM
    if ( yyTok != Tok_Eos && yyTok != Tok_RightParen && yyTok != Tok_Bar )
    parseFactor( box );
#endif
    while ( yyTok != Tok_Eos && yyTok != Tok_RightParen && yyTok != Tok_Bar ) {
    Box rightBox( this );
    parseFactor( &rightBox );
    box->cat( rightBox );
    }
}

void QRegExpEngine::parseExpression( Box *box )
{
    parseTerm( box );
    while ( yyTok == Tok_Bar ) {
    Box rightBox( this );
    yyTok = getToken();
    parseTerm( &rightBox );
    box->orx( rightBox );
    }
}

/*
  The class QRegExpPrivate contains the private data of a regular expression
  other than the automaton.  It makes it possible for many QRegExp objects to
  use the same QRegExpEngine object with different QRegExpPrivate objects.
*/
struct QRegExpPrivate
{
    QString pattern; // regular-expression or wildcard pattern
    QString rxpattern; // regular-expression pattern
#ifndef QT_NO_REGEXP_WILDCARD
    bool wc; // wildcard mode?
#endif
    bool min; // minimal matching? (instead of maximal)
#ifndef QT_NO_REGEXP_CAPTURE
    QString t; // last string passed to QRegExp::search() or searchRev()
    QStringList capturedCache; // what QRegExp::capturedTexts() returned last
#endif
    QArray<int> captured; // what QRegExpEngine::search() returned last

    QRegExpPrivate() { captured.fill( -1, 2 ); }
};

#ifndef QT_NO_REGEXP_OPTIM
static QCache<QRegExpEngine> *engineCache = 0;
#endif

static QRegExpEngine *newEngine( const QString& pattern, bool caseSensitive )
{
#ifndef QT_NO_REGEXP_OPTIM
    if ( engineCache != 0 ) {
    QRegExpEngine *eng = engineCache->take( pattern );
    if ( eng == 0 || eng->caseSensitive() != caseSensitive ) {
        delete eng;
    } else {
        eng->ref();
        return eng;
    }
    }
#endif
    return new QRegExpEngine( pattern, caseSensitive );
}

static void derefEngine( QRegExpEngine *eng, const QString& pattern )
{
    if ( eng != 0 && eng->deref() ) {
#ifndef QT_NO_REGEXP_OPTIM
    if ( engineCache == 0 ) {
        engineCache = new QCache<QRegExpEngine>;
        engineCache->setAutoDelete( TRUE );
    }
    if ( !pattern.isNull() &&
         engineCache->insert(pattern, eng, 4 + pattern.length() / 4) )
        return;
#else
    Q_UNUSED( pattern );
#endif
    delete eng;
    }
}

QRegExp3::QRegExp3()
{
    eng = new QRegExpEngine( TRUE );
    priv = new QRegExpPrivate;
    priv->pattern = QString::null;
#ifndef QT_NO_REGEXP_WILDCARD
    priv->wc = FALSE;
#endif
    priv->min = FALSE;
    compile( TRUE );
}

QRegExp3::QRegExp3( const QString& pattern, bool caseSensitive, bool wildcard )
{
    eng = 0;
    priv = new QRegExpPrivate;
    priv->pattern = pattern;
#ifndef QT_NO_REGEXP_WILDCARD
    priv->wc = wildcard;
#endif
    priv->min = FALSE;
    compile( caseSensitive );
}

QRegExp3::QRegExp3( const QRegExp3& rx )
{
    eng = 0;
    priv = new QRegExpPrivate;
    operator=( rx );
}

QRegExp3::~QRegExp3()
{
    derefEngine( eng, priv->rxpattern );
    delete priv;
}

QRegExp3& QRegExp3::operator=( const QRegExp3& rx )
{
    rx.eng->ref();
    derefEngine( eng, priv->rxpattern );
    eng = rx.eng;
    priv->pattern = rx.priv->pattern;
    priv->rxpattern = rx.priv->rxpattern;
#ifndef QT_NO_REGEXP_WILDCARD
    priv->wc = rx.priv->wc;
#endif
    priv->min = rx.priv->min;
#ifndef QT_NO_REGEXP_CAPTURE
    priv->t = rx.priv->t;
    priv->capturedCache = rx.priv->capturedCache;
#endif
    priv->captured = rx.priv->captured;
    return *this;
}

bool QRegExp3::operator==( const QRegExp3& rx ) const
{
    return priv->pattern == rx.priv->pattern &&
       eng->caseSensitive() == rx.eng->caseSensitive() &&
#ifndef QT_NO_REGEXP_WILDCARD
       priv->wc == rx.priv->wc &&
#endif
       priv->min == rx.priv->min;
}

bool QRegExp3::isEmpty() const
{
    return priv->pattern.isEmpty();
}

bool QRegExp3::isValid() const
{
    return eng->isValid();
}

QString QRegExp3::pattern() const
{
    return priv->pattern;
}

void QRegExp3::setPattern( const QString& pattern )
{
    if ( priv->pattern != pattern ) {
    priv->pattern = pattern;
    compile( caseSensitive() );
    }
}

bool QRegExp3::caseSensitive() const
{
    return eng->caseSensitive();
}

void QRegExp3::setCaseSensitive( bool sensitive )
{
    if ( sensitive != eng->caseSensitive() )
    compile( sensitive );
}

#ifndef QT_NO_REGEXP_WILDCARD

bool QRegExp3::wildcard() const
{
    return priv->wc;
}

void QRegExp3::setWildcard( bool wildcard )
{
    if ( wildcard != priv->wc ) {
    priv->wc = wildcard;
    compile( caseSensitive() );
    }
}
#endif

bool QRegExp3::minimal() const
{
    return priv->min;
}

void QRegExp3::setMinimal( bool minimal )
{
    priv->min = minimal;
}

bool QRegExp3::exactMatch( const QString& str )
{
#ifndef QT_NO_REGEXP_CAPTURE
    priv->t = str;
    priv->capturedCache.clear();
#endif

    priv->captured = eng->match( str, 0, priv->min, TRUE );
    if ( priv->captured[1] == (int) str.length() ) {
    return TRUE;
    } else {
    priv->captured.detach();
    priv->captured[0] = 0;
    priv->captured[1] = eng->matchedLength();
    return FALSE;
    }
}

bool QRegExp3::exactMatch( const QString& str ) const
{
   return eng->match(str, 0, priv->min, TRUE)[0] == 0 &&
      eng->matchedLength() == (int) str.length();
}

#ifndef QT_NO_COMPAT
int QRegExp3::match( const QString& str, int index, int *len,
            bool indexIsStart )
{
    int pos;
    if ( indexIsStart ) {
    pos = search( str.mid(index) );
    if ( pos >= 0 ) {
        pos += index;
        if ( len != 0 )
        *len = matchedLength();
    } else {
        if ( len != 0 )
        *len = 0;
    }
    } else {
    pos = search( str, index );
    if ( len != 0 )
        *len = matchedLength();
    }
    return pos;
}
#endif

// QChar versions

#ifdef QCHAR_SUPPORT
const QString makeString(const QChar *str)
{
// A sentinel value checked in case the QChar *ptr is never null terminated
    const uint MAXLENGTH=65535;

    const QChar *s=str;
    uint i=0;
    while(i < MAXLENGTH && *s != QChar::null) {  i++;s++ ;}
    return QString(str,i);

}
int QRegExp3::search(const QChar *str,int start)
{
    return search(makeString(str),start);
}
int QRegExp3::search(const QChar *str,int start) const
{
    return search(makeString(str),start);
}
int QRegExp3::searchRev(const QChar *str,int start)
{
    return searchRev(makeString(str),start);
}
int QRegExp3::searchRev(const QChar *str,int start) const
{
    return searchRev(makeString(str),start);
}
bool QRegExp3::exactMatch(const QChar *str)
{
    return exactMatch(makeString(str));
}
bool QRegExp3::exactMatch(const QChar *str) const
{
    return exactMatch(makeString(str));
}
#endif // QCHAR_SUPPORT

int QRegExp3::search( const QString& str, int start )
{
    if ( start < 0 )
    start += str.length();
#ifndef QT_NO_REGEXP_CAPTURE
    priv->t = str;
    priv->capturedCache.clear();
#endif
    priv->captured = eng->match( str, start, priv->min, FALSE );
    return priv->captured[0];
}

int QRegExp3::search( const QString& str, int start ) const
{
    if ( start < 0 )
    start += str.length();
    return eng->match( str, start, priv->min, FALSE )[0];
}

int QRegExp3::searchRev( const QString& str, int start )
{
    if ( start < 0 )
    start += str.length();
#ifndef QT_NO_REGEXP_CAPTURE
    priv->t = str;
    priv->capturedCache.clear();
#endif
    if ( start < 0 || start > (int) str.length() ) {
    priv->captured.detach();
    priv->captured.fill( -1 );
    return -1;
    }

    while ( start >= 0 ) {
    priv->captured = eng->match( str, start, priv->min, TRUE );
    if ( priv->captured[0] == start )
        return start;
    start--;
    }
    return -1;
}

int QRegExp3::searchRev( const QString& str, int start ) const
{
    if ( start < 0 )
    start += str.length();
    if ( start < 0 || start > (int) str.length() )
    return -1;

    while ( start >= 0 ) {
    if ( eng->match(str, start, priv->min, TRUE)[0] == start )
        return start;
    start--;
    }
    return -1;
}

int QRegExp3::matchedLength()
{
    return priv->captured[1];
}

#ifndef QT_NO_REGEXP_CAPTURE

QStringList QRegExp3::capturedTexts()
{
    if ( priv->capturedCache.isEmpty() ) {
    for ( int i = 0; i < (int) priv->captured.size(); i += 2 ) {
        QString m;
        if ( priv->captured[i + 1] == 0 )
        m = QString::fromLatin1( "" );
        else if ( priv->captured[i] >= 0 )
        m = priv->t.mid( priv->captured[i],
                 priv->captured[i + 1] );
        priv->capturedCache.append( m );
    }
    priv->t = QString::null;
    }
    return priv->capturedCache;
}

QString QRegExp3::cap( int nth )
{
    if ( nth < 0 || nth >= (int) priv->captured.size() / 2 )
    return QString::null;
    else
    return capturedTexts()[nth];
}

int QRegExp3::pos( int nth )
{
    if ( nth < 0 || nth >= (int) priv->captured.size() / 2 )
    return -1;
    else
    return priv->captured[2 * nth];
}
#endif

void QRegExp3::compile( bool caseSensitive )
{
    derefEngine( eng, priv->rxpattern );
#ifndef QT_NO_REGEXP_WILDCARD
    if ( priv->wc )
    priv->rxpattern = wc2rx( priv->pattern );
    else
#endif
    priv->rxpattern = priv->pattern.isNull() ? QString::fromLatin1( "" )
              : priv->pattern;
    eng = newEngine( priv->rxpattern, caseSensitive );
#ifndef QT_NO_REGEXP_CAPTURE
    priv->t = QString::null;
    priv->capturedCache.clear();
#endif
    priv->captured.detach();
    priv->captured.fill( -1, 2 + 2 * eng->numCaptures() );
}

---