qiodevice.cpp

奇趣公司比较新的qt/emd版本

}

/*! \fn bool QIODevice::putChar(char c)

    Writes the character \a c to the device. Returns true on success;
    otherwise returns false.

    \sa write() getChar() ungetChar()
*/
bool QIODevice::putChar(char c)
{
    return d_func()->putCharHelper(c);
}

/*!
    \internal
*/
bool QIODevicePrivate::putCharHelper(char c)
{
    return q_func()->write(&c, 1) == 1;
}

/*! \fn bool QIODevice::getChar(char *c)

    Reads one character from the device and stores it in \a c. If \a c
    is 0, the character is discarded. Returns true on success;
    otherwise returns false.

    \sa read() putChar() ungetChar()
*/
bool QIODevice::getChar(char *c)
{
    Q_D(QIODevice);
    const OpenMode openMode = d->openMode;
    if (!(openMode & ReadOnly)) {
        if (openMode == NotOpen)
            qWarning("QIODevice::getChar: Closed device");
        else
            qWarning("QIODevice::getChar: WriteOnly device");
        return false;
    }

    // Shortcut for QIODevice::read(c, 1)
    QRingBuffer *buffer = &d->buffer;
    const int chint = buffer->getChar();
    if (chint != -1) {
        char ch = char(uchar(chint));
        if ((openMode & Text) && ch == '\r') {
            buffer->ungetChar(ch);
        } else {
            if (c)
                *c = ch;
            if (!d->isSequential())
                ++d->pos;
            return true;
        }
    }

    // Fall back to read().
    char ch;
    if (read(&ch, 1) == 1) {
        if (c)
            *c = ch;
        return true;
    }
    return false;
}

/*!
    \since 4.1

    Reads at most \a maxSize bytes from the device into \a data, without side
    effects (i.e., if you call read() after peek(), you will get the same
    data).  Returns the number of bytes read. If an error occurs, such as
    when attempting to peek a device opened in WriteOnly mode, this function
    returns -1.

    0 is returned when no more data is available for reading.

    Example:

    \code
        bool isExeFile(QFile *file)
        {
            char buf[2];
            if (file->peek(buf, sizeof(buf)) == sizeof(buf))
                return (buf[0] == 'M' && buf[1] == 'Z');
            return false;
        }
    \endcode

    \sa read()
*/
qint64 QIODevice::peek(char *data, qint64 maxSize)
{
    qint64 readBytes = read(data, maxSize);
    int i = readBytes;
    while (i > 0)
        ungetChar(data[i-- - 1]);
    return readBytes;
}

/*!
    \since 4.1
    \overload

    Peeks at most \a maxSize bytes from the device, returning the data peeked
    as a QByteArray.

    Example:

    \code
        bool isExeFile(QFile *file)
        {
            return file->peek(2) == "MZ";
        }
    \endcode

    This function has no way of reporting errors; returning an empty
    QByteArray() can mean either that no data was currently available
    for peeking, or that an error occurred.

    \sa read()
*/
QByteArray QIODevice::peek(qint64 maxSize)
{
    QByteArray result = read(maxSize);
    int i = result.size();
    const char *data = result.constData();
    while (i > 0)
        ungetChar(data[i-- - 1]);
    return result;
}

/*!
    Blocks until data is available for reading and the readyRead()
    signal has been emitted, or until \a msecs milliseconds have
    passed. If msecs is -1, this function will not time out.

    Returns true if data is available for reading; otherwise returns
    false (if the operation timed out or if an error occurred).

    This function can operate without an event loop. It is
    useful when writing non-GUI applications and when performing
    I/O operations in a non-GUI thread.

    If called from within a slot connected to the readyRead() signal,
    readyRead() will not be reemitted.

    Reimplement this function to provide a blocking API for a custom
    device. The default implementation does nothing, and returns false.

    \warning Calling this function from the main (GUI) thread
    might cause your user interface to freeze.

    \sa waitForBytesWritten()
*/
bool QIODevice::waitForReadyRead(int msecs)
{
    Q_UNUSED(msecs);
    return false;
}

/*!
    For buffered devices, this function waits until a payload of
    buffered written data has been written to the device and the
    bytesWritten() signal has been emitted, or until \a msecs
    milliseconds have passed. If msecs is -1, this function will
    not time out. For unbuffered devices, it returns immediately.

    Returns true if a payload of data was written to the device;
    otherwise returns false (i.e. if the operation timed out, or if an
    error occurred).

    This function can operate without an event loop. It is
    useful when writing non-GUI applications and when performing
    I/O operations in a non-GUI thread.

    If called from within a slot connected to the bytesWritten() signal,
    bytesWritten() will not be reemitted.

    Reimplement this function to provide a blocking API for a custom
    device. The default implementation does nothing, and returns false.

    \warning Calling this function from the main (GUI) thread
    might cause your user interface to freeze.

    \sa waitForReadyRead()
*/
bool QIODevice::waitForBytesWritten(int msecs)
{
    Q_UNUSED(msecs);
    return false;
}

/*!
    Sets the human readable description of the last device error that
    occurred to \a str.

    \sa errorString()
*/
void QIODevice::setErrorString(const QString &str)
{
    d_func()->errorString = str;
}

/*!
    Returns a human-readable description of the last device error that
    occurred.

    \sa setErrorString()
*/
QString QIODevice::errorString() const
{
    Q_D(const QIODevice);
    if (d->errorString.isEmpty()) {
#ifdef QT_NO_QOBJECT
        return QLatin1String(QT_TRANSLATE_NOOP(QIODevice, "Unknown error"));
#else
        return tr("Unknown error");
#endif
    }
    return d->errorString;
}

/*!
    \fn qint64 QIODevice::readData(char *data, qint64 maxSize)

    Reads up to \a maxSize bytes from the device into \a data, and
    returns the number of bytes read or -1 if an error occurred.

    This function is called by QIODevice. Reimplement this function
    when creating a subclass of QIODevice.

    \sa read() readLine() writeData()
*/

/*!
    \fn qint64 QIODevice::writeData(const char *data, qint64 maxSize)

    Writes up to \a maxSize bytes from \a data to the device. Returns
    the number of bytes written, or -1 if an error occurred.

    This function is called by QIODevice. Reimplement this function
    when creating a subclass of QIODevice.

    \sa read() write()
*/

/*!
    \fn QIODevice::Offset QIODevice::status() const

    For device specific error handling, please refer to the
    individual device documentation.

    \sa qobject_cast()
*/

/*!
    \fn QIODevice::Offset QIODevice::at() const

    Use pos() instead.
*/

/*!
    \fn bool QIODevice::at(Offset offset)

    Use seek(\a offset) instead.
*/

/*! \fn int QIODevice::flags() const

    Use openMode() instead.
*/

/*! \fn int QIODevice::getch()

    Use getChar() instead.
*/

/*!
    \fn bool QIODevice::isAsynchronous() const

    This functionality is no longer available. This function always
    returns true.
*/

/*!
    \fn bool QIODevice::isBuffered() const

    Use !(openMode() & QIODevice::Unbuffered) instead.
*/

/*!
    \fn bool QIODevice::isCombinedAccess() const

    Use openMode() instead.
*/

/*!
    \fn bool QIODevice::isDirectAccess() const

    Use !isSequential() instead.
*/

/*!
    \fn bool QIODevice::isInactive() const

    Use isOpen(), isReadable(), or isWritable() instead.
*/

/*!
    \fn bool QIODevice::isRaw() const

    Use openMode() instead.
*/

/*!
    \fn bool QIODevice::isSequentialAccess() const

    Use isSequential() instead.
*/

/*!
    \fn bool QIODevice::isSynchronous() const

    This functionality is no longer available. This function always
    returns false.
*/

/*!
    \fn bool QIODevice::isTranslated() const

    Use openMode() instead.
*/

/*!
    \fn bool QIODevice::mode() const

    Use openMode() instead.
*/

/*! \fn int QIODevice::putch(int ch)

    Use putChar(\a ch) instead.
*/

/*! \fn int QIODevice::ungetch(int ch)

    Use ungetChar(\a ch) instead.
*/

/*!
    \fn quint64 QIODevice::readBlock(char *data, quint64 size)

    Use read(\a data, \a size) instead.
*/

/*! \fn int QIODevice::state() const

    Use isOpen() instead.
*/

/*!
    \fn qint64 QIODevice::writeBlock(const char *data, quint64 size)

    Use write(\a data, \a size) instead.
*/

/*!
    \fn qint64 QIODevice::writeBlock(const QByteArray &data)

    Use write(\a data) instead.
*/

#if defined QT3_SUPPORT
QIODevice::Status QIODevice::status() const
{
#if !defined(QT_NO_QOBJECT)
    const QFile *f = qobject_cast<const QFile *>(this);
    if (f) return (int) f->error();
#endif
    return isOpen() ? 0 /* IO_Ok */ : 8 /* IO_UnspecifiedError */;
}

/*!
    For device specific error handling, please refer to the
    individual device documentation.

    \sa qobject_cast()
*/
void QIODevice::resetStatus()
{
#if !defined(QT_NO_QOBJECT)
    QFile *f = qobject_cast<QFile *>(this);
    if (f) f->unsetError();
#endif
}
#endif

#if !defined(QT_NO_DEBUG_STREAM)
QDebug operator<<(QDebug debug, QIODevice::OpenMode modes)
{
    debug << "OpenMode(";
    QStringList modeList;
    if (modes == QIODevice::NotOpen) {
        modeList << QLatin1String("NotOpen");
    } else {
        if (modes & QIODevice::ReadOnly)
            modeList << QLatin1String("ReadOnly");
        if (modes & QIODevice::WriteOnly)
            modeList << QLatin1String("WriteOnly");
        if (modes & QIODevice::Append)
            modeList << QLatin1String("Append");
        if (modes & QIODevice::Truncate)
            modeList << QLatin1String("Truncate");
        if (modes & QIODevice::Text)
            modeList << QLatin1String("Text");
        if (modes & QIODevice::Unbuffered)
            modeList << QLatin1String("Unbuffered");
    }
    qSort(modeList);
    debug << modeList.join(QLatin1String("|"));
    debug << ")";
    return debug;
}
#endif