qcstring.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。

/*****************************************************************************
  QByteArray stream functions
 *****************************************************************************/

/*!
    \relates QMemArray

    Writes byte array \a a to the stream \a s and returns a reference
    to the stream.

    \sa \link datastreamformat.html Format of the QDataStream operators \endlink
*/
#ifndef QT_NO_DATASTREAM

QDataStream &operator<<( QDataStream &s, const QByteArray &a )
{
    return s.writeBytes( a.data(), a.size() );
}

/*!
    \relates QMemArray

    Reads a byte array into \a a from the stream \a s and returns a
    reference to the stream.

    \sa \link datastreamformat.html Format of the QDataStream operators \endlink
*/

QDataStream &operator>>( QDataStream &s, QByteArray &a )
{
    Q_UINT32 len;
    s >> len;					// read size of array
    if ( len == 0 || s.eof() ) {		// end of file reached
	a.resize( 0 );
	return s;
    }
    if ( !a.resize( (uint)len ) ) {		// resize array
#if defined(QT_CHECK_NULL)
	qWarning( "QDataStream: Not enough memory to read QByteArray" );
#endif
	len = 0;
    }
    if ( len > 0 )				// not null array
	s.readRawBytes( a.data(), (uint)len );
    return s;
}

#endif //QT_NO_DATASTREAM

/*****************************************************************************
  QCString member functions
 *****************************************************************************/

/*!
    \class QCString qcstring.h
    \reentrant
    \brief The QCString class provides an abstraction of the classic C
    zero-terminated char array (char *).

    \ingroup text
    \ingroup collection
    \ingroup tools
    \ingroup shared

    QCString inherits QByteArray, which is defined as
    QMemArray\<char\>. Since QCString is a QMemArray, it uses \link
    shclass.html explicit sharing\endlink with a reference count.

    QCString tries to behave like a more convenient \c{const char *}.
    The price of doing this is that some algorithms will perform
    badly. For example, append() is O(length()) since it scans for a
    null terminator. Although you might use QCString for text that is
    never exposed to the user, for most purposes, and especially for
    user-visible text, you should use QString. QString provides
    implicit sharing, Unicode and other internationalization support,
    and is well optimized.

    Note that for the QCString methods that take a \c{const char *}
    parameter the \c{const char *} must either be 0 (null) or not-null
    and '\0' (NUL byte) terminated; otherwise the results are
    undefined.

    A QCString that has not been assigned to anything is \e null, i.e.
    both the length and the data pointer is 0. A QCString that
    references the empty string ("", a single '\0' char) is \e empty.
    Both null and empty QCStrings are legal parameters to the methods.
    Assigning \c{const char *} 0 to QCString produces a null QCString.

    The length() function returns the length of the string; resize()
    resizes the string and truncate() truncates the string. A string
    can be filled with a character using fill(). Strings can be left
    or right padded with characters using leftJustify() and
    rightJustify(). Characters, strings and regular expressions can be
    searched for using find() and findRev(), and counted using
    contains().

    Strings and characters can be inserted with insert() and appended
    with append(). A string can be prepended with prepend().
    Characters can be removed from the string with remove() and
    replaced with replace().

    Portions of a string can be extracted using left(), right() and
    mid(). Whitespace can be removed using stripWhiteSpace() and
    simplifyWhiteSpace(). Strings can be converted to uppercase or
    lowercase with upper() and lower() respectively.

    Strings that contain numbers can be converted to numbers with
    toShort(), toInt(), toLong(), toULong(), toFloat() and toDouble().
    Numbers can be converted to strings with setNum().

    Many operators are overloaded to work with QCStrings. QCString
    also supports some more obscure functions, e.g. sprintf(),
    setStr() and setExpand().

    \target asciinotion
    \sidebar Note on Character Comparisons

    In QCString the notion of uppercase and lowercase and of which
    character is greater than or less than another character is locale
    dependent. This affects functions which support a case insensitive
    option or which compare or lowercase or uppercase their arguments.
    Case insensitive operations and comparisons will be accurate if
    both strings contain only ASCII characters. (If \c $LC_CTYPE is
    set, most Unix systems do "the right thing".) Functions that this
    affects include contains(), find(), findRev(), \l operator<(), \l
    operator<=(), \l operator>(), \l operator>=(), lower() and
    upper().

    This issue does not apply to \l{QString}s since they represent
    characters using Unicode.
    \endsidebar

    Performance note: The QCString methods for QRegExp searching are
    implemented by converting the QCString to a QString and performing
    the search on that. This implies a deep copy of the QCString data.
    If you are going to perform many QRegExp searches on a large
    QCString, you will get better performance by converting the
    QCString to a QString yourself, and then searching in the QString.
*/

/*!
    \fn QCString::QCString()

    Constructs a null string.

    \sa isNull()
*/

/*!
    \fn QCString::QCString( const QCString &s )

    Constructs a shallow copy \a s.

    \sa assign()
*/

/*!
    Constructs a string with room for \a size characters, including
    the '\0'-terminator. Makes a null string if \a size == 0.

    If \a size \> 0, then the first and last characters in the string
    are initialized to '\0'. All other characters are uninitialized.

    \sa resize(), isNull()
*/

QCString::QCString( int size )
    : QByteArray( size )
{
    if ( size > 0 ) {
	*data() = '\0';				// set terminator
	*(data()+(size-1)) = '\0';
    }
}

/*!
    Constructs a string that is a deep copy of \a str.

    If \a str is 0 a null string is created.

    \sa isNull()
*/

QCString::QCString( const char *str )
{
    duplicate( str, qstrlen(str) + 1 );
}


/*!
    Constructs a string that is a deep copy of \a str. The copy will
    be at most \a maxsize bytes long including the '\0'-terminator.

    Example:
    \code
    QCString str( "helloworld", 6 ); // assigns "hello" to str
    \endcode

    If \a str contains a 0 byte within the first \a maxsize bytes, the
    resulting QCString will be terminated by this 0. If \a str is 0 a
    null string is created.

    \sa isNull()
*/

QCString::QCString( const char *str, uint maxsize )
{
    if ( str == 0 )
	return;
    uint len; // index of first '\0'
    for ( len = 0; len < maxsize - 1; len++ ) {
	if ( str[len] == '\0' )
	    break;
    }
    QByteArray::resize( len + 1 );
    memcpy( data(), str, len );
    data()[len] = 0;
}

/*!
  \reimp
*/

QCString::~QCString()
{
}

/*!
    \fn QCString &QCString::operator=( const QCString &s )

    Assigns a shallow copy of \a s to this string and returns a
    reference to this string.
*/

/*!
    \overload QCString &QCString::operator=( const char *str )

    Assigns a deep copy of \a str to this string and returns a
    reference to this string.

    If \a str is 0 a null string is created.

    \sa isNull()
*/

/*!
    \fn bool QCString::isNull() const

    Returns TRUE if the string is null, i.e. if data() == 0; otherwise
    returns FALSE. A null string is also an empty string.

    Example:
    \code
    QCString a;		// a.data() == 0,  a.size() == 0, a.length() == 0
    QCString b == "";	// b.data() == "", b.size() == 1, b.length() == 0
    a.isNull();		// TRUE  because a.data() == 0
    a.isEmpty();	// TRUE  because a.length() == 0
    b.isNull();		// FALSE because b.data() == ""
    b.isEmpty();	// TRUE  because b.length() == 0
    \endcode

    \sa isEmpty(), length(), size()
*/

/*!
    \fn bool QCString::isEmpty() const

    Returns TRUE if the string is empty, i.e. if length() == 0;
    otherwise returns FALSE. An empty string is not always a null
    string.

    See example in isNull().

    \sa isNull(), length(), size()
*/

/*!
    \fn uint QCString::length() const

    Returns the length of the string, excluding the '\0'-terminator.
    Equivalent to calling \c strlen(data()).

    Null strings and empty strings have zero length.

    \sa size(), isNull(), isEmpty()
*/

/*!
    \fn bool QCString::truncate( uint pos )

    Truncates the string at position \a pos.

    Equivalent to calling \c resize(pos+1).

    Example:
    \code
    QCString s = "truncate this string";
    s.truncate( 5 );                      // s == "trunc"
    \endcode

    \sa resize()
*/

/*!
    Extends or shrinks the string to \a len bytes, including the
    '\0'-terminator.

    A '\0'-terminator is set at position \c{len - 1} unless
    \c{len == 0}.

    Example:
    \code
    QCString s = "resize this string";
    s.resize( 7 );                      // s == "resize"
    \endcode

    \sa truncate()
*/

bool QCString::resize( uint len )
{
    detach();
    uint wasNull = isNull();
    if ( !QByteArray::resize(len) )
	return FALSE;
    if ( len )
	data()[len - 1] = '\0';
    if ( len > 0 && wasNull )
	data()[0] = '\0';
    return TRUE;
}


/*!
    Implemented as a call to the native vsprintf() (see the manual for
    your C library).

    If the string is shorter than 256 characters, this sprintf() calls
    resize(256) to decrease the chance of memory corruption. The
    string is resized back to its actual length before sprintf()
    returns.

    Example:
    \code
    QCString s;
    s.sprintf( "%d - %s", 1, "first" );		// result < 256 chars

    QCString big( 25000 );			// very long string
    big.sprintf( "%d - %s", 2, longString );	// result < 25000 chars
    \endcode

    \warning All vsprintf() implementations will write past the end of
    the target string (*this) if the \a format specification and
    arguments happen to be longer than the target string, and some
    will also fail if the target string is longer than some arbitrary
    implementation limit.

    Giving user-supplied arguments to sprintf() is risky: Sooner or
    later someone will paste a huge line into your application.
*/

QCString &QCString::sprintf( const char *format, ... )
{
    detach();
    va_list ap;
    va_start( ap, format );
    if ( size() < 256 )
	QByteArray::resize( 256 );		// make string big enough
    vsprintf( data(), format, ap );
    resize( qstrlen(data()) + 1 );		// truncate
    va_end( ap );
    return *this;
}


/*!
    Fills the string with \a len bytes of character \a c, followed by
    a '\0'-terminator.

    If \a len is negative, then the current string length is used.

    Returns FALSE is \a len is nonnegative and there is not enough
    memory to resize the string; otherwise returns TRUE.
*/

bool QCString::fill( char c, int len )
{
    detach();
    if ( len < 0 )
	len = length();
    if ( !QByteArray::fill(c,len+1) )
	return FALSE;
    *(data()+len) = '\0';
    return TRUE;
}


/*!
    \fn QCString QCString::copy() const

    Returns a deep copy of this string.

    \sa detach()
*/


/*!
    Finds the first occurrence of the character \a c, starting at
    position \a index.

    The search is case sensitive if \a cs is TRUE, or case insensitive
    if \a cs is FALSE.

    Returns the position of \a c, or -1 if \a c could not be found.

    \sa \link #asciinotion Note on character comparisons \endlink
*/

int QCString::find( char c, int index, bool cs ) const
{
    if ( (uint)index >= size() )		// index outside string
	return -1;
    register const char *d;
    if ( cs ) {					// case sensitive
	d = strchr( data()+index, c );
    } else {
	d = data()+index;
	c = tolower( (uchar) c );
	while ( *d && tolower((uchar) *d) != c )
	    d++;
	if ( !*d && c )				// not found
	    d = 0;
    }
    return d ? (int)(d - data()) : -1;
}

#define REHASH( a ) \
    if ( sl_minus_1 < sizeof(uint) * CHAR_BIT ) \
	hashHaystack -= (a) << sl_minus_1; \
    hashHaystack <<= 1

/*!
    \overload

    Finds the first occurrence of the string \a str, starting at
    position \a index.

    The search is case sensitive if \a cs is TRUE, or case insensitive
    if \a cs is FALSE.

    Returns the position of \a str, or -1 if \a str could not be
    found.

    \sa \link #asciinotion Note on character comparisons \endlink
*/

int QCString::find( const char *str, int index, bool cs ) const
{
    return find( str, index, cs, length() );
}

int QCString::find( const char *str, int index, bool cs, uint l ) const
{
    if ( (uint)index >= size() )
	return -1;
    if ( !str )
	return -1;
    if ( !*str )
	return index;
    const uint sl = qstrlen( str );
    if ( sl + index > l )
	return -1;

    if ( sl == 1 )
	return find( *str, index, cs );

    /*
      See QString::find() for details.
    */
    const char* needle = str;
    const char* haystack = data() + index;
    const char* end = data() + (l-sl);
    const uint sl_minus_1 = sl-1;
    uint hashNeedle = 0, hashHaystack = 0,i;

    if ( cs ) {
	for ( i = 0; i < sl; ++i ) {
	    hashNeedle = ((hashNeedle<<1) + needle[i] );
	    hashHaystack = ((hashHaystack<<1) + haystack[i] );
	}
	hashHaystack -= *(haystack+sl_minus_1);

	while ( haystack <= end ) {
	    hashHaystack += *(haystack+sl_minus_1);
 	    if ( hashHaystack == hashNeedle  && *needle == *haystack
		 && qstrncmp( needle, haystack, sl ) == 0 )
		return haystack - data();

	    REHASH( *haystack );
	    ++haystack;
	}
    } else {
	for ( i = 0; i < sl; ++i ) {
	    hashNeedle = ((hashNeedle<<1) +
			  tolower( needle[i] ) );