Logo Search packages:      
Sourcecode: qt4-x11 version File versions  Download package

qdatastream.cpp

/****************************************************************************
**
** Copyright (C) 1992-2008 Trolltech ASA. All rights reserved.
**
** This file is part of the QtCore module of the Qt 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. In
** addition, as a special exception, Trolltech gives you certain
** additional rights. These rights are described in the Trolltech GPL
** Exception version 1.1, which can be found at
** http://www.trolltech.com/products/qt/gplexception/ and in the file
** GPL_EXCEPTION.txt in this package.
**
** Please review the following information to ensure GNU General
** Public Licensing requirements will be met:
** http://trolltech.com/products/qt/licenses/licensing/opensource/. If
** you are unsure which license is appropriate for your use, please
** review the following information:
** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
** or contact the sales department at sales@trolltech.com.
**
** In addition, as a special exception, Trolltech, as the sole
** copyright holder for Qt Designer, grants users of the Qt/Eclipse
** Integration plug-in the right for the Qt/Eclipse Integration to
** link to functionality provided by Qt Designer and its related
** libraries.
**
** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE. Trolltech reserves all rights not expressly
** granted herein.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/

#include "qdatastream.h"

#ifndef QT_NO_DATASTREAM
#include "qbuffer.h"
#include "qstring.h"
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>

/*!
    \class QDataStream
    \reentrant
    \brief The QDataStream class provides serialization of binary data
    to a QIODevice.

    \ingroup io
    \mainclass

    A data stream is a binary stream of encoded information which is
    100% independent of the host computer's operating system, CPU or
    byte order. For example, a data stream that is written by a PC
    under Windows can be read by a Sun SPARC running Solaris.

    You can also use a data stream to read/write \l{raw}{raw
    unencoded binary data}. If you want a "parsing" input stream, see
    QTextStream.

    The QDataStream class implements the serialization of C++'s basic
    data types, like \c char, \c short, \c int, \c{char *}, etc.
    Serialization of more complex data is accomplished by breaking up
    the data into primitive units.

    A data stream cooperates closely with a QIODevice. A QIODevice
    represents an input/output medium one can read data from and write
    data to. The QFile class is an example of an I/O device.

    Example (write binary data to a stream):

    \code
        QFile file("file.dat");
        file.open(QIODevice::WriteOnly);
        QDataStream out(&file);   // we will serialize the data into the file
        out << "the answer is";   // serialize a string
        out << (qint32)42;        // serialize an integer
    \endcode

    Example (read binary data from a stream):

    \code
        QFile file("file.dat");
        file.open(QIODevice::ReadOnly);
        QDataStream in(&file);    // read the data serialized from the file
        QString str;
        qint32 a;
        in >> str >> a;           // extract "the answer is" and 42
    \endcode

    Each item written to the stream is written in a predefined binary
    format that varies depending on the item's type. Supported Qt
    types include QBrush, QColor, QDateTime, QFont, QPixmap, QString,
    QVariant and many others. For the complete list of all Qt types
    supporting data streaming see the \l{Format of the QDataStream
    operators}.

    For integers it is best to always cast to a Qt integer type for
    writing, and to read back into the same Qt integer type. This
    ensures that you get integers of the size you want and insulates
    you from compiler and platform differences.

    To take one example, a \c{char *} string is written as a 32-bit
    integer equal to the length of the string including the '\\0' byte,
    followed by all the characters of the string including the
    '\\0' byte. When reading a \c{char *} string, 4 bytes are read to
    create the 32-bit length value, then that many characters for the
    \c {char *} string including the '\\0' terminator are read.

    The initial I/O device is usually set in the constructor, but can be
    changed with setDevice(). If you've reached the end of the data
    (or if there is no I/O device set) atEnd() will return true.

    \section1 Versioning

    QDataStream's binary format has evolved since Qt 1.0, and is
    likely to continue evolving to reflect changes done in Qt. When
    inputting or outputting complex types, it's very important to
    make sure that the same version of the stream (version()) is used
    for reading and writing. If you need both forward and backward
    compatibility, you can hardcode the version number in the
    application:

    \code
        stream.setVersion(QDataStream::Qt_4_0);
    \endcode

    If you are producing a new binary data format, such as a file
    format for documents created by your application, you could use a
    QDataStream to write the data in a portable format. Typically, you
    would write a brief header containing a magic string and a version
    number to give yourself room for future expansion. For example:

    \code
        QFile file("file.xxx");
        file.open(QIODevice::WriteOnly);
        QDataStream out(&file);

        // Write a header with a "magic number" and a version
        out << (quint32)0xA0B0C0D0;
        out << (qint32)123;

        out.setVersion(QDataStream::Qt_4_0);

        // Write the data
        out << lots_of_interesting_data;
    \endcode

    Then read it in with:

    \code
        QFile file("file.xxx");
        file.open(QIODevice::ReadOnly);
        QDataStream in(&file);

        // Read and check the header
        quint32 magic;
        in >> magic;
        if (magic != 0xA0B0C0D0)
            return XXX_BAD_FILE_FORMAT;

        // Read the version
        qint32 version;
        in >> version;
        if (version < 100)
            return XXX_BAD_FILE_TOO_OLD;
        if (version > 123)
            return XXX_BAD_FILE_TOO_NEW;

        if (version <= 110)
            in.setVersion(QDataStream::Qt_3_2);
        else
            in.setVersion(QDataStream::Qt_4_0);

        // Read the data
        in >> lots_of_interesting_data;
        if (version >= 120)
            in >> data_new_in_XXX_version_1_2;
        in >> other_interesting_data;
    \endcode

    You can select which byte order to use when serializing data. The
    default setting is big endian (MSB first). Changing it to little
    endian breaks the portability (unless the reader also changes to
    little endian). We recommend keeping this setting unless you have
    special requirements.

    \target raw
    \section1 Reading and writing raw binary data

    You may wish to read/write your own raw binary data to/from the
    data stream directly. Data may be read from the stream into a
    preallocated \c{char *} using readRawData(). Similarly data can be
    written to the stream using writeRawData(). Note that any
    encoding/decoding of the data must be done by you.

    A similar pair of functions is readBytes() and writeBytes(). These
    differ from their \e raw counterparts as follows: readBytes()
    reads a quint32 which is taken to be the length of the data to be
    read, then that number of bytes is read into the preallocated
    \c{char *}; writeBytes() writes a quint32 containing the length of the
    data, followed by the data. Note that any encoding/decoding of
    the data (apart from the length quint32) must be done by you.

    \sa QTextStream QVariant
*/

/*!
    \enum QDataStream::ByteOrder

    The byte order used for reading/writing the data.

    \value BigEndian Most significant byte first (the default)
    \value LittleEndian Less significant byte first
*/

/*!
    \enum QDataStream::Status

    This enum describes the current status of the data stream.

    \value Ok               The data stream is operating normally.
    \value ReadPastEnd      The data stream has read past the end of the
                            data in the underlying device.
    \value ReadCorruptData  The data stream has read corrupt data.
*/

/*****************************************************************************
  QDataStream member functions
 *****************************************************************************/

#undef  CHECK_STREAM_PRECOND
#ifndef QT_NO_DEBUG
#define CHECK_STREAM_PRECOND(retVal) \
    if (!dev) { \
        qWarning("QDataStream: No device"); \
        return retVal; \
    }
#else
#define CHECK_STREAM_PRECOND(retVal) \
    if (!dev) { \
        return retVal; \
    }
#endif

enum {
    DefaultStreamVersion = QDataStream::Qt_4_3
};

// ### 4.0: when streaming invalid QVariants, just the type should
// be written, no "data" after it

/*!
    Constructs a data stream that has no I/O device.

    \sa setDevice()
*/

00269 QDataStream::QDataStream()
{
    dev = 0;
    owndev = false;
    byteorder = BigEndian;
    ver = DefaultStreamVersion;
    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
    q_status = Ok;
}

/*!
    Constructs a data stream that uses the I/O device \a d.

    \warning If you use QSocket or QSocketDevice as the I/O device \a d
    for reading data, you must make sure that enough data is available
    on the socket for the operation to successfully proceed;
    QDataStream does not have any means to handle or recover from
    short-reads.

    \sa setDevice(), device()
*/

00291 QDataStream::QDataStream(QIODevice *d)
{
    dev = d;                                // set device
    owndev = false;
    byteorder = BigEndian;                        // default byte order
    ver = DefaultStreamVersion;
    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
    q_status = Ok;
}

#ifdef QT3_SUPPORT
/*!
    \fn QDataStream::QDataStream(QByteArray *array, int mode)
    \compat

    Constructs a data stream that operates on the given \a array. The
    \a mode specifies how the byte array is to be used, and is
    usually either QIODevice::ReadOnly or QIODevice::WriteOnly.
*/
QDataStream::QDataStream(QByteArray *a, int mode)
{
    QBuffer *buf = new QBuffer(a);
    buf->open(QIODevice::OpenMode(mode));
    dev = buf;
    owndev = true;
    byteorder = BigEndian;
    ver = DefaultStreamVersion;
    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
    q_status = Ok;
}
#endif

/*!
    \fn QDataStream::QDataStream(QByteArray *a, QIODevice::OpenMode mode)

    Constructs a data stream that operates on a byte array, \a a. The
    \a mode describes how the device is to be used.

    Alternatively, you can use QDataStream(const QByteArray &) if you
    just want to read from a byte array.

    Since QByteArray is not a QIODevice subclass, internally a QBuffer
    is created to wrap the byte array.
*/

00336 QDataStream::QDataStream(QByteArray *a, QIODevice::OpenMode flags)
{
    QBuffer *buf = new QBuffer(a);
    buf->open(flags);
    dev = buf;
    owndev = true;
    byteorder = BigEndian;
    ver = DefaultStreamVersion;
    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
    q_status = Ok;
}

/*!
    Constructs a read-only data stream that operates on byte array \a a.
    Use QDataStream(QByteArray*, int) if you want to write to a byte
    array.

    Since QByteArray is not a QIODevice subclass, internally a QBuffer
    is created to wrap the byte array.
*/
00356 QDataStream::QDataStream(const QByteArray &a)
{
    QBuffer *buf = new QBuffer;
    buf->setData(a);
    buf->open(QIODevice::ReadOnly);
    dev = buf;
    owndev = true;
    byteorder = BigEndian;
    ver = DefaultStreamVersion;
    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
    q_status = Ok;
}

/*!
    Destroys the data stream.

    The destructor will not affect the current I/O device, unless it is
    an internal I/O device (e.g. a QBuffer) processing a QByteArray
    passed in the \e constructor, in which case the internal I/O device
    is destroyed.
*/

00378 QDataStream::~QDataStream()
{
    if (owndev)
        delete dev;
}


/*!
    \fn QIODevice *QDataStream::device() const

    Returns the I/O device currently set.

    \sa setDevice(), unsetDevice()
*/

/*!
    void QDataStream::setDevice(QIODevice *d)

    Sets the I/O device to \a d.

    \sa device(), unsetDevice()
*/

00401 void QDataStream::setDevice(QIODevice *d)
{
    if (owndev) {
        delete dev;
        owndev = false;
    }
    dev = d;
}

/*!
    Unsets the I/O device. This is the same as calling setDevice(0).

    \sa device(), setDevice()
*/

00416 void QDataStream::unsetDevice()
{
    setDevice(0);
}


/*!
    \fn bool QDataStream::atEnd() const

    Returns true if the I/O device has reached the end position (end of
    the stream or file) or if there is no I/O device set; otherwise
    returns false.

    \sa QIODevice::atEnd()
*/

00432 bool QDataStream::atEnd() const
{
    return dev ? dev->atEnd() : true;
}

/*!
    Returns the status of the data stream.

    \sa Status setStatus() resetStatus()
*/

00443 QDataStream::Status QDataStream::status() const
{
    return q_status;
}

/*!
    Resets the status of the data stream.

    \sa Status status() setStatus()
*/
00453 void QDataStream::resetStatus()
{
    q_status = Ok;
}

/*!
    Sets the status of the data stream to the \a status given.

    \sa Status status() resetStatus()
*/
00463 void QDataStream::setStatus(Status status)
{
    if (q_status == Ok)
        q_status = status;
}

/*!\fn bool QDataStream::eof() const

    Use atEnd() instead.
*/

/*!
    \fn int QDataStream::byteOrder() const

    Returns the current byte order setting -- either BigEndian or
    LittleEndian.

    \sa setByteOrder()
*/

/*!
    Sets the serialization byte order to \a bo.

    The \a bo parameter can be QDataStream::BigEndian or
    QDataStream::LittleEndian.

    The default setting is big endian. We recommend leaving this
    setting unless you have special requirements.

    \sa byteOrder()
*/

00495 void QDataStream::setByteOrder(ByteOrder bo)
{
    byteorder = bo;
    if (QSysInfo::ByteOrder == QSysInfo::BigEndian)
        noswap = (byteorder == BigEndian);
    else
        noswap = (byteorder == LittleEndian);
}


/*!
    \fn bool QDataStream::isPrintableData() const

    In Qt 4, this function always returns false.

    \sa setPrintableData()
*/

/*!
    \fn void QDataStream::setPrintableData(bool enable)

    In Qt 3, this function enabled output in a human-readable
    format if \a enable was false.

    In Qt 4, QDataStream no longer provides a human-readable output.
    This function does nothing.
*/

/*!
    \enum QDataStream::Version

    This enum provides symbolic synonyms for the data serialization
    format version numbers.

    \value Qt_1_0 Version 1 (Qt 1.x)
    \value Qt_2_0 Version 2 (Qt 2.0)
    \value Qt_2_1 Version 3 (Qt 2.1, 2.2, 2.3)
    \value Qt_3_0 Version 4 (Qt 3.0)
    \value Qt_3_1 Version 5 (Qt 3.1, 3.2)
    \value Qt_3_3 Version 6 (Qt 3.3)
    \value Qt_4_0 Version 7 (Qt 4.0, Qt 4.1)
    \value Qt_4_1 Version 7 (Qt 4.0, Qt 4.1)
    \value Qt_4_2 Version 8 (Qt 4.2)
    \value Qt_4_3 Version 9 (Qt 4.3)

    \sa setVersion(), version()
*/

/*!
    \fn int QDataStream::version() const

    Returns the version number of the data serialization format.

    \sa setVersion(), Version
*/

/*!
    \fn void QDataStream::setVersion(int v)

    Sets the version number of the data serialization format to \a v.

    You don't \e have to set a version if you are using the current
    version of Qt, but for your own custom binary formats we
    recommend that you do; see \l{Versioning} in the Detailed
    Description.

    In order to accommodate new functionality, the datastream
    serialization format of some Qt classes has changed in some
    versions of Qt. If you want to read data that was created by an
    earlier version of Qt, or write data that can be read by a
    program that was compiled with an earlier version of Qt, use this
    function to modify the serialization format used by QDataStream.

    \table
    \header \i Qt Version       \i QDataStream Version
    \row \i Qt 4.2              \i 8
    \row \i Qt 4.0              \i 7
    \row \i Qt 3.3              \i 6
    \row \i Qt 3.1, 3.2         \i 5
    \row \i Qt 3.0              \i 4
    \row \i Qt 2.1, 2.2, 2.3    \i 3
    \row \i Qt 2.0              \i 2
    \row \i Qt 1.x              \i 1
    \endtable

    The \l Version enum provides symbolic constants for the different
    versions of Qt. For example:

    \code
        QDataStream out(file);
        out.setVersion(QDataStream::Qt_4_0);
    \endcode

    \sa version(), Version
*/

/*****************************************************************************
  QDataStream read functions
 *****************************************************************************/

/*!
    \fn QDataStream &QDataStream::operator>>(quint8 &i)
    \overload

    Reads an unsigned byte from the stream into \a i, and returns a
    reference to the stream.
*/

/*!
    Reads a signed byte from the stream into \a i, and returns a
    reference to the stream.
*/

00608 QDataStream &QDataStream::operator>>(qint8 &i)
{
    i = 0;
    CHECK_STREAM_PRECOND(*this)
    char c;
    if (!dev->getChar(&c))
        setStatus(ReadPastEnd);
    else
        i = qint8(c);
    return *this;
}


/*!
    \fn QDataStream &QDataStream::operator>>(quint16 &i)
    \overload

    Reads an unsigned 16-bit integer from the stream into \a i, and
    returns a reference to the stream.
*/

/*!
    \overload

    Reads a signed 16-bit integer from the stream into \a i, and
    returns a reference to the stream.
*/

00636 QDataStream &QDataStream::operator>>(qint16 &i)
{
    i = 0;
    CHECK_STREAM_PRECOND(*this)
    if (noswap) {
        if (dev->read((char *)&i, 2) != 2) {
            i = 0;
            setStatus(ReadPastEnd);
        }
    } else {
        register uchar *p = (uchar *)(&i);
        char b[2];
        if (dev->read(b, 2) == 2) {
            *p++ = b[1];
            *p = b[0];
        } else {
            setStatus(ReadPastEnd);
        }
    }
    return *this;
}


/*!
    \fn QDataStream &QDataStream::operator>>(quint32 &i)
    \overload

    Reads an unsigned 32-bit integer from the stream into \a i, and
    returns a reference to the stream.
*/

/*!
    \overload

    Reads a signed 32-bit integer from the stream into \a i, and
    returns a reference to the stream.
*/

00674 QDataStream &QDataStream::operator>>(qint32 &i)
{
    i = 0;
    CHECK_STREAM_PRECOND(*this)
    if (noswap) {
        if (dev->read((char *)&i, 4) != 4) {
            i = 0;
            setStatus(ReadPastEnd);
        }
    } else {                                        // swap bytes
        uchar *p = (uchar *)(&i);
        char b[4];
        if (dev->read(b, 4) == 4) {
            *p++ = b[3];
            *p++ = b[2];
            *p++ = b[1];
            *p   = b[0];
        } else {
            setStatus(ReadPastEnd);
        }
    }
    return *this;
}

/*!
    \fn QDataStream &QDataStream::operator>>(quint64 &i)
    \overload

    Reads an unsigned 64-bit integer from the stream, into \a i, and
    returns a reference to the stream.
*/

/*!
    \overload

    Reads a signed 64-bit integer from the stream into \a i, and
    returns a reference to the stream.
*/

00713 QDataStream &QDataStream::operator>>(qint64 &i)
{
    i = qint64(0);
    CHECK_STREAM_PRECOND(*this)
    if (version() < 6) {
        quint32 i1, i2;
        *this >> i2 >> i1;
        i = ((quint64)i1 << 32) + i2;
    } else if (noswap) {                        // no conversion needed
        if (dev->read((char *)&i, 8) != 8) {
            i = qint64(0);
            setStatus(ReadPastEnd);
        }
    } else {                                        // swap bytes
        uchar *p = (uchar *)(&i);
        char b[8];
        if (dev->read(b, 8) == 8) {
            *p++ = b[7];
            *p++ = b[6];
            *p++ = b[5];
            *p++ = b[4];
            *p++ = b[3];
            *p++ = b[2];
            *p++ = b[1];
            *p   = b[0];
        } else {
            setStatus(ReadPastEnd);
        }
    }
    return *this;
}

/*!
    Reads a boolean value from the stream into \a i. Returns a
    reference to the stream.
*/
00749 QDataStream &QDataStream::operator>>(bool &i)
{
    qint8 v;
    *this >> v;
    i = !!v;
    return *this;
}

/*!
    \overload

    Reads a 32-bit floating point number from the stream into \a f,
    using the standard IEEE 754 format. Returns a reference to the
    stream.
*/

00765 QDataStream &QDataStream::operator>>(float &f)
{
    f = 0.0f;
    CHECK_STREAM_PRECOND(*this)
    if (noswap) {
        if (dev->read((char *)&f, 4) != 4) {
            f = 0.0f;
            setStatus(ReadPastEnd);
        }
    } else {                                        // swap bytes
        uchar *p = (uchar *)(&f);
        char b[4];
        if (dev->read(b, 4) == 4) {
            *p++ = b[3];
            *p++ = b[2];
            *p++ = b[1];
            *p = b[0];
        } else {
            setStatus(ReadPastEnd);
        }
    }
    return *this;
}

#if defined(Q_DOUBLE_FORMAT)
#define Q_DF(x) Q_DOUBLE_FORMAT[(x)] - '0'
#endif

/*!
    \overload

    Reads a 64-bit floating point number from the stream into \a f,
    using the standard IEEE 754 format. Returns a reference to the
    stream.
*/

00801 QDataStream &QDataStream::operator>>(double &f)
{
    f = 0.0;
    CHECK_STREAM_PRECOND(*this)
#ifndef Q_DOUBLE_FORMAT
    if (noswap) {
        if (dev->read((char *)&f, 8) != 8) {
            f = 0.0;
            setStatus(ReadPastEnd);
        }
    } else {                                        // swap bytes
        register uchar *p = (uchar *)(&f);
        char b[8];
        if (dev->read(b, 8) == 8) {
            *p++ = b[7];
            *p++ = b[6];
            *p++ = b[5];
            *p++ = b[4];
            *p++ = b[3];
            *p++ = b[2];
            *p++ = b[1];
            *p   = b[0];
        } else {
            setStatus(ReadPastEnd);
        }
    }
#else
    //non-standard floating point format
    register uchar *p = (uchar *)(&f);
    char b[8];
    if (dev->read(b, 8) == 8) {
        if (noswap) {
            *p++ = b[Q_DF(0)];
            *p++ = b[Q_DF(1)];
            *p++ = b[Q_DF(2)];
            *p++ = b[Q_DF(3)];
            *p++ = b[Q_DF(4)];
            *p++ = b[Q_DF(5)];
            *p++ = b[Q_DF(6)];
            *p = b[Q_DF(7)];
        } else {
            *p++ = b[Q_DF(7)];
            *p++ = b[Q_DF(6)];
            *p++ = b[Q_DF(5)];
            *p++ = b[Q_DF(4)];
            *p++ = b[Q_DF(3)];
            *p++ = b[Q_DF(2)];
            *p++ = b[Q_DF(1)];
            *p = b[Q_DF(0)];
        }
    } else {
        setStatus(ReadPastEnd);
    }
#endif
    return *this;
}


/*!
    \overload

    Reads the '\0'-terminated string \a s from the stream and returns
    a reference to the stream.

    Space for the string is allocated using \c new -- the caller must
    destroy it with \c{delete[]}.
*/

00869 QDataStream &QDataStream::operator>>(char *&s)
{
    uint len = 0;
    return readBytes(s, len);
}


/*!
    Reads the buffer \a s from the stream and returns a reference to
    the stream.

    The buffer \a s is allocated using \c new. Destroy it with the \c
    delete[] operator.

    The \a l parameter is set to the length of the buffer. If the
    string read is empty, \a l is set to 0 and \a s is set to
    a null pointer.

    The serialization format is a quint32 length specifier first,
    then \a l bytes of data.

    \sa readRawData(), writeBytes()
*/

00893 QDataStream &QDataStream::readBytes(char *&s, uint &l)
{
    s = 0;
    l = 0;
    CHECK_STREAM_PRECOND(*this)

    quint32 len;
    *this >> len;
    if (len == 0)
        return *this;

    const quint32 Step = 1024 * 1024;
    quint32 allocated = 0;
    char *prevBuf = 0;
    char *curBuf = 0;

    do {
        int blockSize = qMin(Step, len - allocated);
        prevBuf = curBuf;
        curBuf = new char[allocated + blockSize + 1];
        if (prevBuf) {
            memcpy(curBuf, prevBuf, allocated);
            delete [] prevBuf;
        }
        if (dev->read(curBuf + allocated, blockSize) != blockSize) {
            delete [] curBuf;
            setStatus(ReadPastEnd);
            return *this;
        }
        allocated += blockSize;
    } while (allocated < len);

    s = curBuf;
    s[len] = '\0';
    l = (uint)len;
    return *this;
}

/*!
    Reads at most \a len bytes from the stream into \a s and returns the number of
    bytes read. If an error occurs, this function returns -1.

    The buffer \a s must be preallocated. The data is \e not encoded.

    \sa readBytes(), QIODevice::read(), writeRawData()
*/

00940 int QDataStream::readRawData(char *s, int len)
{
    CHECK_STREAM_PRECOND(-1)
    return dev->read(s, len);
}


/*****************************************************************************
  QDataStream write functions
 *****************************************************************************/


/*!
    \fn QDataStream &QDataStream::operator<<(quint8 i)
    \overload

    Writes an unsigned byte, \a i, to the stream and returns a
    reference to the stream.
*/

/*!
    Writes a signed byte, \a i, to the stream and returns a reference
    to the stream.
*/

00965 QDataStream &QDataStream::operator<<(qint8 i)
{
    CHECK_STREAM_PRECOND(*this)
    dev->putChar(i);
    return *this;
}


/*!
    \fn QDataStream &QDataStream::operator<<(quint16 i)
    \overload

    Writes an unsigned 16-bit integer, \a i, to the stream and returns
    a reference to the stream.
*/

/*!
    \overload

    Writes a signed 16-bit integer, \a i, to the stream and returns a
    reference to the stream.
*/

00988 QDataStream &QDataStream::operator<<(qint16 i)
{
    CHECK_STREAM_PRECOND(*this)
    if (noswap) {
        dev->write((char *)&i, sizeof(qint16));
    } else {                                        // swap bytes
        register uchar *p = (uchar *)(&i);
        char b[2];
        b[1] = *p++;
        b[0] = *p;
        dev->write(b, 2);
    }
    return *this;
}

/*!
    \overload

    Writes a signed 32-bit integer, \a i, to the stream and returns a
    reference to the stream.
*/

01010 QDataStream &QDataStream::operator<<(qint32 i)
{
    CHECK_STREAM_PRECOND(*this)
    if (noswap) {
        dev->write((char *)&i, sizeof(qint32));
    } else {                                        // swap bytes
        register uchar *p = (uchar *)(&i);
        char b[4];
        b[3] = *p++;
        b[2] = *p++;
        b[1] = *p++;
        b[0] = *p;
        dev->write(b, 4);
    }
    return *this;
}

/*!
    \fn QDataStream &QDataStream::operator<<(quint64 i)
    \overload

    Writes an unsigned 64-bit integer, \a i, to the stream and returns a
    reference to the stream.
*/

/*!
    \overload

    Writes a signed 64-bit integer, \a i, to the stream and returns a
    reference to the stream.
*/

01042 QDataStream &QDataStream::operator<<(qint64 i)
{
    CHECK_STREAM_PRECOND(*this)
    if (version() < 6) {
      quint32 i1 = i & 0xffffffff;
      quint32 i2 = i >> 32;
      *this << i2 << i1;
    } else if (noswap) {                        // no conversion needed
        dev->write((char *)&i, sizeof(qint64));
    } else {                                        // swap bytes
        register uchar *p = (uchar *)(&i);
        char b[8];
        b[7] = *p++;
        b[6] = *p++;
        b[5] = *p++;
        b[4] = *p++;
        b[3] = *p++;
        b[2] = *p++;
        b[1] = *p++;
        b[0] = *p;
        dev->write(b, 8);
    }
    return *this;
}

/*!
    \fn QDataStream &QDataStream::operator<<(quint32 i)
    \overload

    Writes an unsigned integer, \a i, to the stream as a 32-bit
    unsigned integer (quint32). Returns a reference to the stream.
*/

/*!
    Writes a boolean value, \a i, to the stream. Returns a reference
    to the stream.
*/

01080 QDataStream &QDataStream::operator<<(bool i)
{
    CHECK_STREAM_PRECOND(*this)
    dev->putChar(qint8(i));
    return *this;
}

/*!
    \overload

    Writes a 32-bit floating point number, \a f, to the stream using
    the standard IEEE 754 format. Returns a reference to the stream.
*/

01094 QDataStream &QDataStream::operator<<(float f)
{
    CHECK_STREAM_PRECOND(*this)
    float g = f;                                // fixes float-on-stack problem
    if (noswap) {                                // no conversion needed
        dev->write((char *)&g, sizeof(float));
    } else {                                // swap bytes
        register uchar *p = (uchar *)(&g);
        char b[4];
        b[3] = *p++;
        b[2] = *p++;
        b[1] = *p++;
        b[0] = *p;
        dev->write(b, 4);
    }
    return *this;
}


/*!
    \overload

    Writes a 64-bit floating point number, \a f, to the stream using
    the standard IEEE 754 format. Returns a reference to the stream.
*/

01120 QDataStream &QDataStream::operator<<(double f)
{
    CHECK_STREAM_PRECOND(*this)
#ifndef Q_DOUBLE_FORMAT
    if (noswap) {
        dev->write((char *)&f, sizeof(double));
    } else {
        register uchar *p = (uchar *)(&f);
        char b[8];
        b[7] = *p++;
        b[6] = *p++;
        b[5] = *p++;
        b[4] = *p++;
        b[3] = *p++;
        b[2] = *p++;
        b[1] = *p++;
        b[0] = *p;
        dev->write(b, 8);
    }
#else
    register uchar *p = (uchar *)(&f);
    char b[8];
    if (noswap) {
        b[Q_DF(0)] = *p++;
        b[Q_DF(1)] = *p++;
        b[Q_DF(2)] = *p++;
        b[Q_DF(3)] = *p++;
        b[Q_DF(4)] = *p++;
        b[Q_DF(5)] = *p++;
        b[Q_DF(6)] = *p++;
        b[Q_DF(7)] = *p;
    } else {
        b[Q_DF(7)] = *p++;
        b[Q_DF(6)] = *p++;
        b[Q_DF(5)] = *p++;
        b[Q_DF(4)] = *p++;
        b[Q_DF(3)] = *p++;
        b[Q_DF(2)] = *p++;
        b[Q_DF(1)] = *p++;
        b[Q_DF(0)] = *p;
    }
    dev->write(b, 8);
#endif
    return *this;
}


/*!
    \overload

    Writes the '\0'-terminated string \a s to the stream and returns a
    reference to the stream.

    The string is serialized using writeBytes().
*/

01176 QDataStream &QDataStream::operator<<(const char *s)
{
    if (!s) {
        *this << (quint32)0;
        return *this;
    }
    uint len = qstrlen(s) + 1;                        // also write null terminator
    *this << (quint32)len;                        // write length specifier
    writeRawData(s, len);
    return *this;
}


/*!
    Writes the length specifier \a len and the buffer \a s to the
    stream and returns a reference to the stream.

    The \a len is serialized as a quint32, followed by \a len bytes
    from \a s. Note that the data is \e not encoded.

    \sa writeRawData(), readBytes()
*/

01199 QDataStream &QDataStream::writeBytes(const char *s, uint len)
{
    CHECK_STREAM_PRECOND(*this)
    *this << (quint32)len;                        // write length specifier
    if (len)
        writeRawData(s, len);
    return *this;
}


/*!
    Writes \a len bytes from \a s to the stream. Returns the
    number of bytes actually written, or -1 on error.
    The data is \e not encoded.

    \sa writeBytes(), QIODevice::write(), readRawData()
*/

01217 int QDataStream::writeRawData(const char *s, int len)
{
    CHECK_STREAM_PRECOND(-1)
    return dev->write(s, len);
}

/*!
    \since 4.1

    Skips \a len bytes from the device. Returns the number of bytes
    actually skipped, or -1 on error.

    This is equivalent to calling readRawData() on a buffer of length
    \a len and ignoring the buffer.

    \sa QIODevice::seek()
*/
01234 int QDataStream::skipRawData(int len)
{
    CHECK_STREAM_PRECOND(-1)

    if (dev->isSequential()) {
        char buf[4096];
        int sumRead = 0;

        while (len > 0) {
            int blockSize = qMin(len, (int)sizeof(buf));
            int n = dev->read(buf, blockSize);
            if (n == -1)
                return -1;
            if (n == 0)
                return sumRead;

            sumRead += n;
            len -= blockSize;
        }
        return sumRead;
    } else {
        quint64 pos = dev->pos();
        len = qMin(int(dev->size() - pos), len);
        if (!dev->seek(pos + len))
            return -1;
        return len;
    }
}

#ifdef QT3_SUPPORT
/*!
    \fn QDataStream &QDataStream::readRawBytes(char *str, uint len)

    Use readRawData() instead.
*/

/*!
    \fn QDataStream &QDataStream::writeRawBytes(const char *str, uint len)

    Use writeRawData() instead.
*/
#endif

#endif // QT_NO_DATASTREAM

Generated by  Doxygen 1.6.0   Back to index