qt3/src/kernel/qkeysequence.cpp

/****************************************************************************
**
** Implementation of QKeySequence class
**
** Created : 0108007
**
** Copyright (C) 1992-2008 Trolltech ASA.  All rights reserved.
**
** This file is part of the kernel module of the Qt GUI Toolkit.
**
** This file may be used under the terms of the GNU General
** Public License versions 2.0 or 3.0 as published by the Free
** Software Foundation and appearing in the files LICENSE.GPL2
** and LICENSE.GPL3 included in the packaging of this file.
** Alternatively you may (at your option) use any later version
** of the GNU General Public License if such license has been
** publicly approved by Trolltech ASA (or its successors, if any)
** and the KDE Free Qt Foundation.
**
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** If you are unsure which license is appropriate for your use, please
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** Commercial licenses may use this file in accordance with the Qt
** Commercial License Agreement provided with the Software.
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**********************************************************************/

#include "qkeysequence.h"

#ifndef QT_NO_ACCEL

#include "qaccel.h"
#include "qshared.h"
#include "qvaluelist.h"
#ifndef QT_NO_REGEXP
# include "qregexp.h"
#endif

#ifdef Q_WS_MAC
#define QMAC_CTRL  (QString(QChar(0x2318)))
#define QMAC_META  (QString(QChar(0x2303)))
#define QMAC_ALT   (QString(QChar(0x2325)))
#define QMAC_SHIFT (QString(QChar(0x21E7)))
#endif

/*!
    \class QKeySequence qkeysequence.h
    \brief The QKeySequence class encapsulates a key sequence as used
    by accelerators.

    \ingroup misc

    A key sequence consists of up to four keyboard codes, each
    optionally combined with modifiers, e.g. \c SHIFT, \c CTRL, \c
    ALT, \c META, or \c UNICODE_ACCEL. For example, \c{CTRL + Key_P}
    might be a sequence used as a shortcut for printing a document.
    The key codes are listed in \c{qnamespace.h}. As an alternative,
    use \c UNICODE_ACCEL with the unicode code point of the character.
    For example, \c{UNICODE_ACCEL + 'A'} gives the same key sequence
    as \c Key_A.

    Key sequences can be constructed either from an integer key code,
    or from a human readable translatable string such as
    "Ctrl+X,Alt+Space". A key sequence can be cast to a QString to
    obtain a human readable translated version of the sequence.
    Translations are done in the "QAccel" context.

    \sa QAccel
*/

/*!
    \enum Qt::SequenceMatch

    \value NoMatch Sequences have nothing in common
    \value PartialMatch Sequences match partially, but are not complete
    \value Identical Sequences do not differ
*/

static struct {
    int key;
    const char* name;
} keyname[] = {
    { Qt::Key_Space,	    QT_TRANSLATE_NOOP( "QAccel", "Space" ) },
    { Qt::Key_Escape,	    QT_TRANSLATE_NOOP( "QAccel", "Esc" ) },
    { Qt::Key_Tab,	    QT_TRANSLATE_NOOP( "QAccel", "Tab" ) },
    { Qt::Key_Backtab,	    QT_TRANSLATE_NOOP( "QAccel", "Backtab" ) },
    { Qt::Key_Backspace,    QT_TRANSLATE_NOOP( "QAccel", "Backspace" ) },
    { Qt::Key_Return,	    QT_TRANSLATE_NOOP( "QAccel", "Return" ) },
    { Qt::Key_Enter,	    QT_TRANSLATE_NOOP( "QAccel", "Enter" ) },
    { Qt::Key_Insert,	    QT_TRANSLATE_NOOP( "QAccel", "Ins" ) },
    { Qt::Key_Delete,	    QT_TRANSLATE_NOOP( "QAccel", "Del" ) },
    { Qt::Key_Pause,	    QT_TRANSLATE_NOOP( "QAccel", "Pause" ) },
    { Qt::Key_Print,	    QT_TRANSLATE_NOOP( "QAccel", "Print" ) },
    { Qt::Key_SysReq,	    QT_TRANSLATE_NOOP( "QAccel", "SysReq" ) },
    { Qt::Key_Home,	    QT_TRANSLATE_NOOP( "QAccel", "Home" ) },
    { Qt::Key_End,	    QT_TRANSLATE_NOOP( "QAccel", "End" ) },
    { Qt::Key_Left,	    QT_TRANSLATE_NOOP( "QAccel", "Left" ) },
    { Qt::Key_Up,	    QT_TRANSLATE_NOOP( "QAccel", "Up" ) },
    { Qt::Key_Right,	    QT_TRANSLATE_NOOP( "QAccel", "Right" ) },
    { Qt::Key_Down,	    QT_TRANSLATE_NOOP( "QAccel", "Down" ) },
    { Qt::Key_Prior,	    QT_TRANSLATE_NOOP( "QAccel", "PgUp" ) },
    { Qt::Key_Next,	    QT_TRANSLATE_NOOP( "QAccel", "PgDown" ) },
    { Qt::Key_CapsLock,	    QT_TRANSLATE_NOOP( "QAccel", "CapsLock" ) },
    { Qt::Key_NumLock,	    QT_TRANSLATE_NOOP( "QAccel", "NumLock" ) },
    { Qt::Key_ScrollLock,   QT_TRANSLATE_NOOP( "QAccel", "ScrollLock" ) },
    { Qt::Key_Menu,	    QT_TRANSLATE_NOOP( "QAccel", "Menu" ) },
    { Qt::Key_Help,	    QT_TRANSLATE_NOOP( "QAccel", "Help" ) },

    // Multimedia keys
    { Qt::Key_Back,	    QT_TRANSLATE_NOOP( "QAccel", "Back" ) },
    { Qt::Key_Forward,	    QT_TRANSLATE_NOOP( "QAccel", "Forward" ) },
    { Qt::Key_Stop,	    QT_TRANSLATE_NOOP( "QAccel", "Stop" ) },
    { Qt::Key_Refresh,	    QT_TRANSLATE_NOOP( "QAccel", "Refresh" ) },
    { Qt::Key_VolumeDown,   QT_TRANSLATE_NOOP( "QAccel", "Volume Down" ) },
    { Qt::Key_VolumeMute,   QT_TRANSLATE_NOOP( "QAccel", "Volume Mute" ) },
    { Qt::Key_VolumeUp,	    QT_TRANSLATE_NOOP( "QAccel", "Volume Up" ) },
    { Qt::Key_BassBoost,    QT_TRANSLATE_NOOP( "QAccel", "Bass Boost" ) },
    { Qt::Key_BassUp,	    QT_TRANSLATE_NOOP( "QAccel", "Bass Up" ) },
    { Qt::Key_BassDown,	    QT_TRANSLATE_NOOP( "QAccel", "Bass Down" ) },
    { Qt::Key_TrebleUp,	    QT_TRANSLATE_NOOP( "QAccel", "Treble Up" ) },
    { Qt::Key_TrebleDown,   QT_TRANSLATE_NOOP( "QAccel", "Treble Down" ) },
    { Qt::Key_MediaPlay,    QT_TRANSLATE_NOOP( "QAccel", "Media Play" ) },
    { Qt::Key_MediaStop,    QT_TRANSLATE_NOOP( "QAccel", "Media Stop" ) },
    { Qt::Key_MediaPrev,    QT_TRANSLATE_NOOP( "QAccel", "Media Previous" ) },
    { Qt::Key_MediaNext,    QT_TRANSLATE_NOOP( "QAccel", "Media Next" ) },
    { Qt::Key_MediaRecord,  QT_TRANSLATE_NOOP( "QAccel", "Media Record" ) },
    { Qt::Key_HomePage,	    QT_TRANSLATE_NOOP( "QAccel", "Home" ) },
    { Qt::Key_Favorites,    QT_TRANSLATE_NOOP( "QAccel", "Favorites" ) },
    { Qt::Key_Search,	    QT_TRANSLATE_NOOP( "QAccel", "Search" ) },
    { Qt::Key_Standby,	    QT_TRANSLATE_NOOP( "QAccel", "Standby" ) },
    { Qt::Key_OpenUrl,	    QT_TRANSLATE_NOOP( "QAccel", "Open URL" ) },
    { Qt::Key_LaunchMail,   QT_TRANSLATE_NOOP( "QAccel", "Launch Mail" ) },
    { Qt::Key_LaunchMedia,  QT_TRANSLATE_NOOP( "QAccel", "Launch Media" ) },
    { Qt::Key_Launch0,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (0)" ) },
    { Qt::Key_Launch1,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (1)" ) },
    { Qt::Key_Launch2,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (2)" ) },
    { Qt::Key_Launch3,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (3)" ) },
    { Qt::Key_Launch4,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (4)" ) },
    { Qt::Key_Launch5,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (5)" ) },
    { Qt::Key_Launch6,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (6)" ) },
    { Qt::Key_Launch7,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (7)" ) },
    { Qt::Key_Launch8,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (8)" ) },
    { Qt::Key_Launch9,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (9)" ) },
    { Qt::Key_LaunchA,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (A)" ) },
    { Qt::Key_LaunchB,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (B)" ) },
    { Qt::Key_LaunchC,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (C)" ) },
    { Qt::Key_LaunchD,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (D)" ) },
    { Qt::Key_LaunchE,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (E)" ) },
    { Qt::Key_LaunchF,	    QT_TRANSLATE_NOOP( "QAccel", "Launch (F)" ) },

    // --------------------------------------------------------------
    // More consistent namings
    { Qt::Key_Print,	    QT_TRANSLATE_NOOP( "QAccel", "Print Screen" ) },
    { Qt::Key_Prior,	    QT_TRANSLATE_NOOP( "QAccel", "Page Up" ) },
    { Qt::Key_Next,	    QT_TRANSLATE_NOOP( "QAccel", "Page Down" ) },
    { Qt::Key_CapsLock,	    QT_TRANSLATE_NOOP( "QAccel", "Caps Lock" ) },
    { Qt::Key_NumLock,	    QT_TRANSLATE_NOOP( "QAccel", "Num Lock" ) },
    { Qt::Key_NumLock,	    QT_TRANSLATE_NOOP( "QAccel", "Number Lock" ) },
    { Qt::Key_ScrollLock,   QT_TRANSLATE_NOOP( "QAccel", "Scroll Lock" ) },
    { Qt::Key_Insert,	    QT_TRANSLATE_NOOP( "QAccel", "Insert" ) },
    { Qt::Key_Delete,	    QT_TRANSLATE_NOOP( "QAccel", "Delete" ) },
    { Qt::Key_Escape,	    QT_TRANSLATE_NOOP( "QAccel", "Escape" ) },
    { Qt::Key_SysReq,	    QT_TRANSLATE_NOOP( "QAccel", "System Request" ) },

    { 0, 0 }
};


class QKeySequencePrivate : public QShared
{
public:
    inline QKeySequencePrivate()
    {
	key[0] = key[1] = key[2] = key[3] =  0;
    }
    inline QKeySequencePrivate( QKeySequencePrivate *copy )
    {
	key[0] = copy->key[0];
	key[1] = copy->key[1];
	key[2] = copy->key[2];
	key[3] = copy->key[3];
    }
    int key[4];
};


/*!
    Constructs an empty key sequence.
*/
QKeySequence::QKeySequence()
{
    d = new QKeySequencePrivate();
    Q_CHECK_PTR( d );
}

/*!
    Creates a key sequence from the string \a key. For example
    "Ctrl+O" gives CTRL+UNICODE_ACCEL+'O'. The strings "Ctrl",
    "Shift", "Alt" and "Meta" are recognized, as well as their
    translated equivalents in the "QAccel" context (using
    QObject::tr()).

    Multiple key codes (up to four) may be entered by separating them
    with commas, e.g. "Alt+X,Ctrl+S,Q".

    This contructor is typically used with \link QObject::tr() tr
    \endlink(), so that accelerator keys can be replaced in
    translations:

    \code
	QPopupMenu *file = new QPopupMenu( this );
	file->insertItem( tr("&Open..."), this, SLOT(open()),
			  QKeySequence( tr("Ctrl+O", "File|Open") ) );
    \endcode

    Note the \c "File|Open" translator comment. It is by no means
    necessary, but it provides some context for the human translator.
*/
QKeySequence::QKeySequence( const QString& key )
{
    d = new QKeySequencePrivate();
    Q_CHECK_PTR( d );
    assign( key );
}


// ### BCI: Merge with constructor below for 4.0
/*!
    Constructs a key sequence that has a single \a key.

    The key codes are listed in \c{qnamespace.h} and can be
    combined with modifiers, e.g. with \c SHIFT, \c CTRL, \c
    ALT, \c META or \c UNICODE_ACCEL.
*/
QKeySequence::QKeySequence( int key )
{
    d = new QKeySequencePrivate();
    Q_CHECK_PTR( d );
    d->key[0] = key;
}

/*!
    Constructs a key sequence with up to 4 keys \a k1, \a k2,
    \a k3 and \a k4.

    The key codes are listed in \c{qnamespace.h} and can be
    combined with modifiers, e.g. with \c SHIFT, \c CTRL, \c
    ALT, \c META or \c UNICODE_ACCEL.
*/
QKeySequence::QKeySequence( int k1, int k2, int k3, int k4 )
{
    d = new QKeySequencePrivate();
    Q_CHECK_PTR( d );
    d->key[0] = k1;
    d->key[1] = k2;
    d->key[2] = k3;
    d->key[3] = k4;
}

/*!
    Copy constructor. Makes a copy of \a keysequence.
 */
QKeySequence::QKeySequence( const QKeySequence& keysequence )
    : d( keysequence.d )
{
    d->ref();
}


/*!
    Destroys the key sequence.
 */
QKeySequence::~QKeySequence()
{
    if ( d->deref() )
	delete d;
}

/*!
    \internal
    KeySequences should never be modified, but rather just created.
    Internally though we do need to modify to keep pace in event
    delivery.
*/

void QKeySequence::setKey( int key, int index )
{
#ifdef QT_CHECK_STATE
    if ( 0 > index && 4 < index ) {
	qWarning( "QKeySequence::setKey: index %u out of range", index );
	return;
    }
#endif // QT_CHECK_STATE

    if ( 1 < d->count ) {
	QKeySequencePrivate *newd = new QKeySequencePrivate( d );
	d->deref();
	d = newd;
    }
    d->key[index] = key;
}

/*!
    Returns the number of keys in the key sequence.
    The maximum is 4.
 */
uint QKeySequence::count() const
{
    if ( ! d->key[0] )
	return 0;
    if ( ! d->key[1] )
	return 1;
    if ( ! d->key[2] )
	return 2;
    if ( ! d->key[3] )
	return 3;
    return 4;
}


/*!
    Returns TRUE if the key sequence is empty; otherwise returns
    FALSE.
*/
bool QKeySequence::isEmpty() const
{
    return !d->key[0];
}


/*!
    Adds the string \a keyseq to the key sequence. \a keyseq may
    contain up to four key codes, provided they are seperated by a
    comma, e.g. "Alt+X,Ctrl+S,Z"). Returns the number of key codes
    added.
*/
int QKeySequence::assign( QString keyseq )
{
    QString part;
    int n = 0;
    int p = 0, diff = 0;

    // Run through the whole string, but stop
    // if we have 4 keys before the end.
    while ( keyseq.length() && n < 4 ) {
	// We MUST use something to seperate each sequence, and space
	// does not cut it, since some of the key names have space
	// in them.. (Let's hope no one translate with a comma in it:)
	p = keyseq.find( ',' );
	if ( -1 != p ) {
	    if ( ',' == keyseq[p+1] ) // e.g. 'Ctrl+,, Shift+,,'
		p++;
	    if ( ' ' == keyseq[p+1] ) { // Space after comma
		diff = 1;
		p++;
	    } else if ( '\0' == keyseq[p+1] ) { // Last comma 'Ctrl+,'
                p = -1;
	    } else {
		diff = 0;
	    }
	}
	part = keyseq.left( -1==p?keyseq.length():p-diff );
	keyseq = keyseq.right( -1==p?0:keyseq.length() - ( p + 1 ) );
	d->key[n] = decodeString( part );
	n++;
    }
    return n;
}

struct ModifKeyName {
    ModifKeyName() { }
    ModifKeyName(int q, QString n) : qt_key(q), name(n) { }
    int qt_key;
    QString name;
};

/*!
    Constructs a single key from the string \str.
 */
int QKeySequence::decodeString( const QString& str )
{
    int ret = 0;
    QString accel = str;

    QValueList<ModifKeyName> modifs;
#ifdef QMAC_CTRL
    modifs << ModifKeyName( CTRL, QMAC_CTRL );
#endif
#ifdef QMAC_ALT
    modifs << ModifKeyName( ALT, QMAC_ALT );
#endif
#ifdef QMAC_META
    modifs << ModifKeyName( META, QMAC_META );
#endif
#ifdef QMAC_SHIFT
    modifs << ModifKeyName( SHIFT, QMAC_SHIFT );
#endif
    modifs << ModifKeyName( CTRL, "ctrl+" ) << ModifKeyName( CTRL, QAccel::tr("Ctrl").lower().append('+') );
    modifs << ModifKeyName( SHIFT, "shift+" ) << ModifKeyName( SHIFT, QAccel::tr("Shift").lower().append('+') );
    modifs << ModifKeyName( ALT, "alt+" ) << ModifKeyName( ALT, QAccel::tr("Alt").lower().append('+') );
    modifs << ModifKeyName( META, "meta+" ) << ModifKeyName( ALT, QAccel::tr("Meta").lower().append('+') );
    QString sl = accel.lower();
    for( QValueList<ModifKeyName>::iterator it = modifs.begin(); it != modifs.end(); ++it ) {
	if ( sl.contains( (*it).name ) ) {
	    ret |= (*it).qt_key;
#ifndef QT_NO_REGEXP
	    accel.remove( QRegExp(QRegExp::escape((*it).name), FALSE) );
#else
	    accel.remove( (*it).name );
#endif
	    sl = accel.lower();
	}
    }

    int p = accel.findRev( '+', str.length() - 2 ); // -2 so that Ctrl++ works
    if( p > 0 )
	accel = accel.mid( p + 1 );

    int fnum = 0;
    if ( accel.length() == 1 ) {
	char ltr = accel[0].upper().latin1();
	// We can only upper A-Z without problems.
	if ( ltr < (char)Key_A || ltr > (char)Key_Z )
	    ret |= accel[0].unicode();
	else
	    ret |= accel[0].upper().unicode();
	ret |= UNICODE_ACCEL;
    } else if ( accel[0] == 'F' && (fnum = accel.mid(1).toInt()) && (fnum >= 1) && (fnum <= 35) ) {
        ret |= Key_F1 + fnum - 1;
    } else {
	// Check through translation table for the correct key name
	// ...or fall back on english table.
	bool found = FALSE;
	for ( int tran = 0; tran < 2; tran++ ) {
	    for ( int i = 0; keyname[i].name; i++ ) {
		if ( tran ? accel == QAccel::tr(keyname[i].name)
			  : accel == keyname[i].name ) {
		    ret |= keyname[i].key;
		    found = TRUE;
		    break;
		}
	    }
	    if(found)
		break;
	}
    }
    return ret;
}


/*!
    Creates an accelerator string for \a key. For example,
    CTRL+Key_O gives "Ctrl+O". The strings, "Ctrl", "Shift", etc. are
    translated (using QObject::tr()) in the "QAccel" context.
 */
QString QKeySequence::encodeString( int key )
{
    QString s;
#if defined(Q_OS_MAC) && !defined(QWS)
    // On MAC the order is Meta, Alt, Shift, Control.
    if ( (key & META) == META )
	s += QMAC_META;
    if ( (key & ALT) == ALT )
	s += QMAC_ALT;
    if ( (key & SHIFT) == SHIFT )
	s += QMAC_SHIFT;
    if ( (key & CTRL) == CTRL )
	s += QMAC_CTRL;
#else
    // On other systems the order is Meta, Control, Alt, Shift
    if ( (key & META) == META )
	s += QAccel::tr( "Meta" );
    if ( (key & CTRL) == CTRL ) {
	if ( !s.isEmpty() )
	    s += QAccel::tr( "+" );
	s += QAccel::tr( "Ctrl" );
    }
    if ( (key & ALT) == ALT ) {
	if ( !s.isEmpty() )
	    s += QAccel::tr( "+" );
	s += QAccel::tr( "Alt" );
    }
    if ( (key & SHIFT) == SHIFT ) {
	if ( !s.isEmpty() )
	    s += QAccel::tr( "+" );
	s += QAccel::tr( "Shift" );
    }
#endif


    key &= ~(SHIFT | CTRL | ALT | META );
    QString p;

    if ( (key & UNICODE_ACCEL) == UNICODE_ACCEL ) {
	// Note: This character should NOT be upper()'ed, since
	// the encoded string should indicate EXACTLY what the
	// key represents! Hence a 'Ctrl+Shift+c' is posible to
	// represent, but is clearly impossible to trigger...
	p = QChar(key & 0xffff);
    } else if ( key >= Key_F1 && key <= Key_F35 ) {
	p = QAccel::tr( "F%1" ).arg(key - Key_F1 + 1);
    } else if ( key > Key_Space && key <= Key_AsciiTilde ) {
	p.sprintf( "%c", key );
    } else {
	int i=0;
	while (keyname[i].name) {
	    if ( key == keyname[i].key ) {
		p = QAccel::tr(keyname[i].name);
		break;
	    }
	    ++i;
	}
	// If we can't find the actual translatable keyname,
	// fall back on the unicode representation of it...
	// Or else characters like Key_aring may not get displayed
	// ( Really depends on you locale )
	if ( !keyname[i].name )
	    // Note: This character should NOT be upper()'ed, see above!
	    p = QChar(key & 0xffff);
    }

#ifndef Q_OS_MAC
    if ( !s.isEmpty() )
	s += QAccel::tr( "+" );
#endif

    s += p;
    return s;
}

/*!
    Matches the sequence with \a seq. Returns \c Qt::Identical if
    successful, \c Qt::PartialMatch for matching but incomplete \a seq,
    and \c Qt::NoMatch if the sequences have nothing in common.
    Returns \c Qt::NoMatch if \a seq is shorter.
*/
Qt::SequenceMatch QKeySequence::matches( const QKeySequence& seq ) const
{
    uint userN = count(),
	  seqN = seq.count();

    if ( userN > seqN )
	return NoMatch;

    // If equal in length, we have a potential Identical sequence,
    // else we already know it can only be partial.
    SequenceMatch match = ( userN == seqN ? Identical : PartialMatch );

    for ( uint i = 0; i < userN; i++ ) {
	int userKey      = (*this)[i],
	    sequenceKey  = seq[i];

	if ( (userKey & ~Qt::UNICODE_ACCEL) != 
	     (sequenceKey & ~Qt::UNICODE_ACCEL) )
	    return NoMatch;
    }
    return match;
}


/*!
    Creates an accelerator string for the key sequence.
    For instance CTRL+Key_O gives "Ctrl+O". If the key sequence has
    multiple key codes they are returned comma-separated, e.g.
    "Alt+X, Ctrl+Y, Z". The strings, "Ctrl", "Shift", etc. are
    translated (using QObject::tr()) in the "QAccel" scope. If the key
    sequence has no keys, QString::null is returned.

    On Mac OS X, the string returned resembles the sequence that is shown in
    the menubar.
*/
QKeySequence::operator QString() const
{
    int end = count();
    if ( !end ) return QString::null;

    QString complete;
    int i = 0;
    while ( i < end ) {
	complete += encodeString( d->key[i] );
	i++;
	if ( i != end)
	    complete += ", ";
    }
    return complete;
}


/*!
    \obsolete
    For backward compatibility: returns the first keycode
    as integer. If the key sequence is empty, 0 is returned.
 */
QKeySequence::operator int () const
{
    if ( 1 <= count() )
	return d->key[0];
    return 0;
}


/*!
    Returns a reference to the element at position \a index in the key
    sequence. This can only be used to read an element.
 */
int QKeySequence::operator[]( uint index ) const
{
#ifdef QT_CHECK_STATE
    if ( index > 4 ) {
	qWarning( "QKeySequence::operator[]: index %u out of range", index );
	return 0;
    }
#endif // QT_CHECK_STATE
    return d->key[index];
}


/*!
    Assignment operator. Assigns \a keysequence to this
    object.
 */
QKeySequence &QKeySequence::operator=( const QKeySequence & keysequence )
{
    keysequence.d->ref();
    if ( d->deref() )
	delete d;
    d = keysequence.d;
    return *this;
}


/*!
    Returns TRUE if \a keysequence is equal to this key
    sequence; otherwise returns FALSE.
 */


bool QKeySequence::operator==( const QKeySequence& keysequence ) const
{
    return ( (d->key[0]&~UNICODE_ACCEL) == (keysequence.d->key[0]&~UNICODE_ACCEL) &&
	     (d->key[1]&~UNICODE_ACCEL) == (keysequence.d->key[1]&~UNICODE_ACCEL) &&
	     (d->key[2]&~UNICODE_ACCEL) == (keysequence.d->key[2]&~UNICODE_ACCEL) &&
	     (d->key[3]&~UNICODE_ACCEL) == (keysequence.d->key[3]&~UNICODE_ACCEL) );
}


/*!
    Returns TRUE if \a keysequence is not equal to this key sequence;
    otherwise returns FALSE.
*/
bool QKeySequence::operator!= ( const QKeySequence& keysequence ) const
{
    QKeySequence *that = (QKeySequence*)this;
    return !( (*that) == keysequence );
}


/*****************************************************************************
  QKeySequence stream functions
 *****************************************************************************/
#if !defined(QT_NO_DATASTREAM) && !defined(QT_NO_IMAGEIO)
/*!
    \relates QKeySequence

    Writes the key sequence \a keysequence to the stream \a s.

    \sa \link datastreamformat.html Format of the QDataStream operators \endlink
*/
QDataStream &operator<<( QDataStream &s, const QKeySequence &keysequence )
{
    QValueList<int> list;
    list += keysequence.d->key[0];
    list += keysequence.d->key[1];
    list += keysequence.d->key[2];
    list += keysequence.d->key[3];
    s << list;

    return s;
}


/*!
    \relates QKeySequence

    Reads a key sequence from the stream \a s into the key sequence \a
    keysequence.

    \sa \link datastreamformat.html Format of the QDataStream operators \endlink
*/
QDataStream &operator>>( QDataStream &s, QKeySequence &keysequence )
{
    QValueList<int> list;
    s >> list;

#ifdef QT_CHECK_STATE
    if ( 1 != list.count() && 4 != list.count() ) {
	qWarning( "Invalid QKeySequence data in the datastream." );
	return s;
    }
#endif

    if ( 1 == list.count() ) {
	keysequence.d->key[0] = *list.at( 0 );
	keysequence.d->key[1] =
	    keysequence.d->key[2] =
	    keysequence.d->key[3] = 0;
    } else {
	keysequence.d->key[0] = *list.at( 0 );
	keysequence.d->key[1] = *list.at( 1 );
	keysequence.d->key[2] = *list.at( 2 );
	keysequence.d->key[3] = *list.at( 3 );
    }
    return s;
}

#endif //QT_NO_DATASTREAM

#endif //QT_NO_ACCEL