qstring.cpp

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

int QChar::digitValue() const
{
#ifndef QT_NO_UNICODETABLES
    register int pos = QUnicodeTables::decimal_info[row()];
    if( !pos )
	return -1;
    return QUnicodeTables::decimal_info[(pos<<8) + cell()];
#else
    // ##### just latin1
    if ( ucs < '0' || ucs > '9' )
	return -1;
    else
	return ucs - '0';
#endif
}

/*!
    Returns the character category.

    \sa Category
*/
QChar::Category QChar::category() const
{
     return ::category( *this );
}

/*!
    Returns the character's direction.

    \sa Direction
*/
QChar::Direction QChar::direction() const
{
     return ::direction( *this );
}

/*!
    \warning This function is not supported (it may change to use
    Unicode character classes).

    Returns information about the joining properties of the character
    (needed for example, for Arabic).
*/
QChar::Joining QChar::joining() const
{
    return ::joining( *this );
}


/*!
    Returns TRUE if the character is a mirrored character (one that
    should be reversed if the text direction is reversed); otherwise
    returns FALSE.
*/
bool QChar::mirrored() const
{
    return ::mirrored( *this );
}

/*!
    Returns the mirrored character if this character is a mirrored
    character, otherwise returns the character itself.
*/
QChar QChar::mirroredChar() const
{
    return ::mirroredChar( *this );
}

#ifndef QT_NO_UNICODETABLES
// ### REMOVE ME 4.0
static QString shared_decomp;
#endif
/*!
    \nonreentrant

    Decomposes a character into its parts. Returns QString::null if no
    decomposition exists.
*/
const QString &QChar::decomposition() const
{
#ifndef QT_NO_UNICODETABLES
    register int pos = QUnicodeTables::decomposition_info[row()];
    if(!pos) return QString::null;

    pos = QUnicodeTables::decomposition_info[(pos<<8)+cell()];
    if(!pos) return QString::null;
    pos+=2;

    QString s;
    Q_UINT16 c;
    while ( (c = QUnicodeTables::decomposition_map[pos++]) != 0 )
	s += QChar( c );
    // ### In 4.0, return s, and not shared_decomp.  shared_decomp
    // prevents this function from being reentrant.
    shared_decomp = s;
    return shared_decomp;
#else
    return QString::null;
#endif
}

/*!
    Returns the tag defining the composition of the character. Returns
    QChar::Single if no decomposition exists.
*/
QChar::Decomposition QChar::decompositionTag() const
{
#ifndef QT_NO_UNICODETABLES
    register int pos = QUnicodeTables::decomposition_info[row()];
    if(!pos) return QChar::Single;

    pos = QUnicodeTables::decomposition_info[(pos<<8)+cell()];
    if(!pos) return QChar::Single;

    return (QChar::Decomposition) QUnicodeTables::decomposition_map[pos];
#else
    return Single; // ########### FIX eg. just latin1
#endif
}

/*!
    Returns the combining class for the character as defined in the
    Unicode standard. This is mainly useful as a positioning hint for
    marks attached to a base character.

    The Qt text rendering engine uses this information to correctly
    position non spacing marks around a base character.
*/
unsigned char QChar::combiningClass() const
{
    return ::combiningClass( *this );
}


/*!
    Returns the lowercase equivalent if the character is uppercase;
    otherwise returns the character itself.
*/
QChar QChar::lower() const
{
     return ::lower( *this );
}

/*!
    Returns the uppercase equivalent if the character is lowercase;
    otherwise returns the character itself.
*/
QChar QChar::upper() const
{
     return ::upper( *this );
}

/*!
    \fn QChar::operator char() const

    Returns the Latin-1 character equivalent to the QChar, or 0. This
    is mainly useful for non-internationalized software.

    \sa unicode()
*/

/*!
    \fn ushort QChar::unicode() const

    Returns the numeric Unicode value equal to the QChar. Normally,
    you should use QChar objects as they are equivalent, but for some
    low-level tasks (e.g. indexing into an array of Unicode
    information), this function is useful.
*/

/*!
    \fn ushort & QChar::unicode()

    \overload

    Returns a reference to the numeric Unicode value equal to the
    QChar.
*/

/*****************************************************************************
  Documentation of QChar related functions
 *****************************************************************************/

/*!
    \fn bool operator==( QChar c1, QChar c2 )

    \relates QChar

    Returns TRUE if \a c1 and \a c2 are the same Unicode character;
    otherwise returns FALSE.
*/

/*!
    \fn bool operator==( char ch, QChar c )

    \overload
    \relates QChar

    Returns TRUE if \a c is the ASCII/Latin-1 character \a ch;
    otherwise returns FALSE.
*/

/*!
    \fn bool operator==( QChar c, char ch )

    \overload
    \relates QChar

    Returns TRUE if \a c is the ASCII/Latin-1 character \a ch;
    otherwise returns FALSE.
*/

/*!
    \fn int operator!=( QChar c1, QChar c2 )

    \relates QChar

    Returns TRUE if \a c1 and \a c2 are not the same Unicode
    character; otherwise returns FALSE.
*/

/*!
    \fn int operator!=( char ch, QChar c )

    \overload
    \relates QChar

    Returns TRUE if \a c is not the ASCII/Latin-1 character \a ch;
    otherwise returns FALSE.
*/

/*!
    \fn int operator!=( QChar c, char ch )

    \overload
    \relates QChar

    Returns TRUE if \a c is not the ASCII/Latin-1 character \a ch;
    otherwise returns FALSE.
*/

/*!
    \fn int operator<=( QChar c1, QChar c2 )

    \relates QChar

    Returns TRUE if the numeric Unicode value of \a c1 is less than
    that of \a c2, or they are the same Unicode character; otherwise
    returns FALSE.
*/

/*!
    \fn int operator<=( QChar c, char ch )

    \overload
    \relates QChar

    Returns TRUE if the numeric Unicode value of \a c is less than or
    equal to that of the ASCII/Latin-1 character \a ch; otherwise
    returns FALSE.
*/

/*!
    \fn int operator<=( char ch, QChar c )

    \overload
    \relates QChar

    Returns TRUE if the numeric Unicode value of the ASCII/Latin-1
    character \a ch is less than or equal to that of \a c; otherwise
    returns FALSE.
*/

/*!
    \fn int operator>=( QChar c1, QChar c2 )

    \relates QChar

    Returns TRUE if the numeric Unicode value of \a c1 is greater than
    that of \a c2, or they are the same Unicode character; otherwise
    returns FALSE.
*/

/*!
    \fn int operator>=( QChar c, char ch )

    \overload
    \relates QChar

    Returns TRUE if the numeric Unicode value of \a c is greater than
    or equal to that of the ASCII/Latin-1 character \a ch; otherwise
    returns FALSE.
*/

/*!
    \fn int operator>=( char ch, QChar c )

    \overload
    \relates QChar

    Returns TRUE if the numeric Unicode value of the ASCII/Latin-1
    character \a ch is greater than or equal to that of \a c;
    otherwise returns FALSE.
*/

/*!
    \fn int operator<( QChar c1, QChar c2 )

    \relates QChar

    Returns TRUE if the numeric Unicode value of \a c1 is less than
    that of \a c2; otherwise returns FALSE.
*/

/*!
    \fn int operator<( QChar c, char ch )

    \overload
    \relates QChar

    Returns TRUE if the numeric Unicode value of \a c is less than that
    of the ASCII/Latin-1 character \a ch; otherwise returns FALSE.
*/

/*!
    \fn int operator<( char ch, QChar c )

    \overload
    \relates QChar

    Returns TRUE if the numeric Unicode value of the ASCII/Latin-1
    character \a ch is less than that of \a c; otherwise returns
    FALSE.
*/

/*!
    \fn int operator>( QChar c1, QChar c2 )

    \relates QChar

    Returns TRUE if the numeric Unicode value of \a c1 is greater than
    that of \a c2; otherwise returns FALSE.
*/

/*!
    \fn int operator>( QChar c, char ch )

    \overload
    \relates QChar

    Returns TRUE if the numeric Unicode value of \a c is greater than
    that of the ASCII/Latin-1 character \a ch; otherwise returns FALSE.
*/

/*!
    \fn int operator>( char ch, QChar c )

    \overload
    \relates QChar

    Returns TRUE if the numeric Unicode value of the ASCII/Latin-1
    character \a ch is greater than that of \a c; otherwise returns
    FALSE.
*/

#ifndef QT_NO_UNICODETABLES

// small class used internally in QString::Compose()
class QLigature
{
public:
    QLigature( QChar c );

    Q_UINT16 first() { cur = ligatures; return cur ? *cur : 0; }
    Q_UINT16 next() { return cur && *cur ? *(cur++) : 0; }
    Q_UINT16 current() { return cur ? *cur : 0; }

    int match(QString & str, unsigned int index);
    QChar head();
    QChar::Decomposition tag();

private:
    Q_UINT16 *ligatures;
    Q_UINT16 *cur;
};

QLigature::QLigature( QChar c )
{
    register int pos = QUnicodeTables::ligature_info[c.row()];
    if( !pos )
	ligatures = 0;
    else
    {
	pos = QUnicodeTables::ligature_info[(pos<<8)+c.cell()];
	ligatures = (Q_UINT16 *)&(QUnicodeTables::ligature_map[pos]);
    }
    cur = ligatures;
}

QChar QLigature::head()
{
    if(current())
	return QChar(QUnicodeTables::decomposition_map[current()+1]);

    return QChar::null;
}

QChar::Decomposition QLigature::tag()
{
    if(current())
	return (QChar::Decomposition) QUnicodeTables::decomposition_map[current()];

    return QChar::Canonical;
}

int QLigature::match(QString & str, unsigned int index)
{
    unsigned int i=index;

    if(!current()) return 0;

    Q_UINT16 lig = current() + 2;
    Q_UINT16 ch;

    while ((i < str.length()) && (ch = QUnicodeTables::decomposition_map[lig])) {
	if (str[(int)i] != QChar(ch))
	    return 0;
	i++;
	lig++;
    }

    if (!QUnicodeTables::decomposition_map[lig])
    {
	return i-index;
    }
    return 0;
}


// this function is just used in QString::compose()
static inline bool format(QChar::Decomposition tag, QString & str,
			  int index, int len)
{
    unsigned int l = index + len;
    unsigned int r = index;

    bool left = FALSE, right = FALSE;

    left = ((l < str.length()) &&
	    ((str[(int)l].joining() == QChar::Dual) ||
	     (str[(int)l].joining() == QChar::Right)));
    if (r > 0) {
	r--;
	//printf("joining(right) = %d\n", str[(int)r].joining());
	right = (str[(int)r].joining() == QChar::Dual);
    }


    switch (tag) {
    case QChar::Medial:
	return (left & right);
    case QChar::Initial:
	return (left && !right);
    case QChar::Final:
	return (right);// && !left);
    case QChar::Isolated:
    default:
	return (!right && !left);
    }
} // format()
#endif

/*
  QString::compose() and visual() were developed by Gordon Tisher
  <[e-mail]>, with input from Lars Knoll <[e-mail]>,
  who developed the unicode data tables.
*/
/*!
    \warning This function is not supported in Qt 3.x. It is provided
    for experimental and illustrative purposes only. It is mainly of
    interest to those experimenting with Arabic and other
    composition-rich texts.

    Applies possible ligatures to a QString. Useful when
    composition-rich text requires rendering with glyph-poor fonts,
    but it also makes compositions such as QChar(0x0041) ('A') and
    QChar(0x0308) (Unicode accent diaresis), giving QChar(0x00c4)
    (German A Umlaut).
*/
void QString::compose()
{
#ifndef QT_NO_UNICODETABLES
    unsigned int index=0, len;
    unsigned int cindex = 0;

    QChar code, head;

    QMemArray<QChar> dia;

    QString composed = *this;

    while (index < length()) {
	code = at(index);
	//printf("\n\nligature for 0x%x:\n", code.unicode());
	QLigature ligature(code);
	ligature.first();
	while ( ligature.current() ) {
	    if ((len = ligature.match(*this, index)) != 0) {
		head = ligature.head();
		unsigned short code = head.unicode();
		// we exclude Arabic presentation forms A and a few
		// other ligatures, which are undefined in most fonts
		if(!(code > 0xfb50 && code < 0xfe80) &&
		   !(code > 0xfb00 && code < 0xfb2a)) {
				// joining info is only needed for Arabic
		    if (format(ligature.tag(), *this, index, len)) {
			//printf("using ligature 0x%x, len=%d\n",code,len);
			// replace letter
			composed.replace(cindex, len, QChar(head));
			index += len-1;
			// we continue searching in case we have a final
			// form because medial ones are preferred.
			if ( len != 1 || ligature.tag() !=QChar::Final )
			    break;
		    }