Add support for gzip compressed databases.

src/streams/QtIOCompressor

@@ -0,0 +1 @@
+#include "qtiocompressor.h"

src/streams/qtiocompressor.cpp

@@ -0,0 +1,624 @@
+/****************************************************************************
+**
+** Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of a Qt Solutions component.
+**
+** Commercial Usage
+** Licensees holding valid Qt Commercial licenses may use this file in
+** accordance with the Qt Solutions Commercial License Agreement provided
+** with the Software or, alternatively, in accordance with the terms
+** contained in a written agreement between you and Nokia.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.1, included in the file LICENSE.NOKIA-LGPL-EXCEPTION
+** in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL-3 included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** Please note Third Party Software included with Qt Solutions may impose
+** additional restrictions and it is the user's responsibility to ensure
+** that they have met the licensing requirements of the GPL, LGPL, or Qt
+** Solutions Commercial license and the relevant license of the Third
+** Party Software they are using.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact Nokia at qt-info@nokia.com.
+**
+****************************************************************************/
+
+#include "qtiocompressor.h"
+#include "zlib.h"
+#include <QtCore/QDebug>
+
+typedef Bytef ZlibByte;
+typedef uInt ZlibSize;
+
+class QtIOCompressorPrivate {
+    QtIOCompressor *q_ptr;
+    Q_DECLARE_PUBLIC(QtIOCompressor)
+public:
+    enum State {
+        // Read state
+        NotReadFirstByte,
+        InStream,
+        EndOfStream,
+        // Write state
+        NoBytesWritten,
+        BytesWritten,
+        // Common
+        Closed,
+        Error
+    };
+
+    QtIOCompressorPrivate(QtIOCompressor *q_ptr, QIODevice *device, int compressionLevel, int bufferSize);
+    ~QtIOCompressorPrivate();
+    void flushZlib(int flushMode);
+    bool writeBytes(ZlibByte *buffer, ZlibSize outputSize);
+    void setZlibError(const QString &erroMessage, int zlibErrorCode);
+
+    QIODevice *device;
+    bool manageDevice;
+    z_stream zlibStream;
+    const int compressionLevel;
+    const ZlibSize bufferSize;
+    ZlibByte *buffer;
+    State state;
+    QtIOCompressor::StreamFormat streamFormat;
+};
+
+/*!
+    \internal
+*/
+QtIOCompressorPrivate::QtIOCompressorPrivate(QtIOCompressor *q_ptr, QIODevice *device, int compressionLevel, int bufferSize)
+:q_ptr(q_ptr)
+,device(device)
+,compressionLevel(compressionLevel)
+,bufferSize(bufferSize)
+,buffer(new ZlibByte[bufferSize])
+,state(Closed)
+,streamFormat(QtIOCompressor::ZlibFormat)
+{
+    // Use default zlib memory management.
+    zlibStream.zalloc = Z_NULL;
+    zlibStream.zfree = Z_NULL;
+    zlibStream.opaque = Z_NULL;
+}
+
+/*!
+    \internal
+*/
+QtIOCompressorPrivate::~QtIOCompressorPrivate()
+{
+    delete[] buffer;
+}
+
+/*!
+    \internal
+    Flushes the zlib stream.
+*/
+void QtIOCompressorPrivate::flushZlib(int flushMode)
+{
+    // No input.
+    zlibStream.next_in = 0;
+    zlibStream.avail_in = 0;
+    int status;
+    do {
+        zlibStream.next_out = buffer;
+        zlibStream.avail_out = bufferSize;
+        status = deflate(&zlibStream, flushMode);
+        if (status != Z_OK && status != Z_STREAM_END) {
+            state = QtIOCompressorPrivate::Error;
+            setZlibError(QT_TRANSLATE_NOOP("QtIOCompressor", "Internal zlib error when compressing: "), status);
+            return;
+        }
+
+        ZlibSize outputSize = bufferSize - zlibStream.avail_out;
+
+        // Try to write data from the buffer to to the underlying device, return on failure.
+        if (!writeBytes(buffer, outputSize))
+            return;
+
+    // If the mode is Z_FNISH we must loop until we get Z_STREAM_END,
+    // else we loop as long as zlib is able to fill the output buffer.
+    } while ((flushMode == Z_FINISH && status != Z_STREAM_END) || (flushMode != Z_FINISH && zlibStream.avail_out == 0));
+
+    if (flushMode == Z_FINISH)
+        Q_ASSERT(status == Z_STREAM_END);
+    else
+        Q_ASSERT(status == Z_OK);
+}
+
+/*!
+    \internal
+    Writes outputSize bytes from buffer to the inderlying device.
+*/
+bool QtIOCompressorPrivate::writeBytes(ZlibByte *buffer, ZlibSize outputSize)
+{
+    Q_Q(QtIOCompressor);
+    ZlibSize totalBytesWritten = 0;
+    // Loop until all bytes are written to the underlying device.
+    do {
+        const qint64 bytesWritten = device->write(reinterpret_cast<char *>(buffer), outputSize);
+        if (bytesWritten == -1) {
+            q->setErrorString(QT_TRANSLATE_NOOP("QtIOCompressor", "Error writing to underlying device: ") + device->errorString());
+            return false;
+        }
+        totalBytesWritten += bytesWritten;
+    } while (totalBytesWritten != outputSize);
+
+    // put up a flag so that the device will be flushed on close.
+    state = BytesWritten;
+    return true;
+}
+
+/*!
+    \internal
+    Sets the error string to errorMessage + zlib error string for zlibErrorCode
+*/
+void QtIOCompressorPrivate::setZlibError(const QString &errorMessage, int zlibErrorCode)
+{
+    Q_Q(QtIOCompressor);
+    // Watch out, zlibErrorString may be null.
+    const char * const zlibErrorString = zError(zlibErrorCode);
+    QString errorString;
+    if (zlibErrorString)
+        errorString = errorMessage + zlibErrorString;
+    else
+        errorString = errorMessage  + " Unknown error, code " + QString::number(zlibErrorCode);
+
+    q->setErrorString(errorString);
+}
+
+/*! \class QtIOCompressor
+    \brief The QtIOCompressor class is a QIODevice that compresses data streams.
+
+    A QtIOCompressor object is constructed with a pointer to an
+    underlying QIODevice.  Data written to the QtIOCompressor object
+    will be compressed before it is written to the underlying
+    QIODevice. Similary, if you read from the QtIOCompressor object,
+    the data will be read from the underlying device and then
+    decompressed.
+
+    QtIOCompressor is a sequential device, which means that it does
+    not support seeks or random access. Internally, QtIOCompressor
+    uses the zlib library to compress and uncompress data.
+
+    Usage examples:
+    Writing compressed data to a file:
+    \code
+        QFile file("foo");
+        QtIOCompressor compressor(&file);
+        compressor.open(QIODevice::WriteOnly);
+        compressor.write(QByteArray() << "The quick brown fox");
+        compressor.close();
+    \endcode
+
+    Reading compressed data from a file:
+    \code
+        QFile file("foo");
+        QtIOCompressor compressor(&file);
+        compressor.open(QIODevice::ReadOnly);
+        const QByteArray text = compressor.readAll();
+        compressor.close();
+    \endcode
+
+    QtIOCompressor can also read and write compressed data in
+    different compressed formats, ref. StreamFormat. Use
+    setStreamFormat() before open() to select format.
+*/
+
+/*!
+    \enum QtIOCompressor::StreamFormat
+    This enum specifies which stream format to use.
+
+    \value ZlibFormat: This is the default and has the smallest overhead.
+
+    \value GzipFormat: This format is compatible with the gzip file
+    format, but has more overhead than ZlibFormat. Note: requires zlib
+    version 1.2.x or higher at runtime.
+
+    \value RawZipFormat: This is compatible with the most common
+    compression method of the data blocks contained in ZIP
+    archives. Note: ZIP file headers are not read or generated, so
+    setting this format, by itself, does not let QtIOCompressor read
+    or write ZIP files. Ref. the ziplist example program.
+
+    \sa setStreamFormat()
+*/
+
+/*!
+    Constructs a QtIOCompressor using the given \a device as the underlying device.
+
+    The allowed value range for \a compressionLevel is 0 to 9, where 0 means no compression
+    and 9 means maximum compression. The default value is 6.
+
+    \a bufferSize specifies the size of the internal buffer used when reading from and writing to the
+    underlying device. The default value is 65KB. Using a larger value allows for faster compression and
+    deompression at the expense of memory usage.
+*/
+QtIOCompressor::QtIOCompressor(QIODevice *device, int compressionLevel, int bufferSize)
+:d_ptr(new QtIOCompressorPrivate(this, device, compressionLevel, bufferSize))
+{}
+
+/*!
+    Destroys the QtIOCompressor, closing it if neccesary.
+*/
+QtIOCompressor::~QtIOCompressor()
+{
+    Q_D(QtIOCompressor);
+    close();
+    delete d;
+}
+
+/*!
+    Sets the format on the compressed stream to \a format.
+
+    \sa QtIOCompressor::StreamFormat
+*/
+void QtIOCompressor::setStreamFormat(StreamFormat format)
+{
+    Q_D(QtIOCompressor);
+
+    // Print a waning if the compile-time version of zlib does not support gzip.
+    if (format == GzipFormat && checkGzipSupport(ZLIB_VERSION) == false)
+        qWarning("QtIOCompressor::setStreamFormat: zlib 1.2.x or higher is "
+                 "required to use the gzip format. Current version is: %s",
+                 ZLIB_VERSION);
+
+    d->streamFormat = format;
+}
+
+/*!
+    Returns the format set on the compressed stream.
+    \sa QtIOCompressor::StreamFormat
+*/
+QtIOCompressor::StreamFormat QtIOCompressor::streamFormat() const
+{
+    Q_D(const QtIOCompressor);
+    return d->streamFormat;
+}
+
+/*!
+    Returns true if the zlib library in use supports the gzip format, false otherwise.
+*/
+bool QtIOCompressor::isGzipSupported()
+{
+    return checkGzipSupport(zlibVersion());
+}
+
+/*!
+    \reimp
+*/
+bool QtIOCompressor::isSequential() const
+{
+    return true;
+}
+
+/*!
+    Opens the QtIOCompressor in \a mode. Only ReadOnly and WriteOnly is supported.
+    This functon will return false if you try to open in other modes.
+
+    If the underlying device is not opened, this function will open it in a suitable mode. If this happens
+    the device will also be closed when close() is called.
+
+    If the underlying device is already opened, its openmode must be compatable with \a mode.
+
+    Returns true on success, false on error.
+
+    \sa close()
+*/
+bool QtIOCompressor::open(OpenMode mode)
+{
+    Q_D(QtIOCompressor);
+    if (isOpen()) {
+        qWarning("QtIOCompressor::open: device already open");
+        return false;
+    }
+
+    // Check for correct mode: ReadOnly xor WriteOnly
+    const bool read = (mode & ReadOnly);
+    const bool write = (mode & WriteOnly);
+    const bool both = (read && write);
+    const bool neither = !(read || write);
+    if (both || neither) {
+        qWarning("QtIOCompressor::open: QtIOCompressor can only be opened in the ReadOnly or WriteOnly modes");
+        return false;
+    }
+
+    // If the underlying device is open, check that is it opened in a compatible mode.
+    if (d->device->isOpen()) {
+        d->manageDevice = false;
+        const OpenMode deviceMode = d->device->openMode();
+        if (read && !(deviceMode & ReadOnly)) {
+            qWarning("QtIOCompressor::open: underlying device must be open in one of the ReadOnly or WriteOnly modes");
+            return false;
+        } else if (write && !(deviceMode & WriteOnly)) {
+            qWarning("QtIOCompressor::open: underlying device must be open in one of the ReadOnly or WriteOnly modes");
+            return false;
+        }
+
+    // If the underlying device is closed, open it.
+    } else {
+        d->manageDevice = true;
+        if (d->device->open(mode) == false) {
+            setErrorString(QT_TRANSLATE_NOOP("QtIOCompressor", "Error opening underlying device: ") + d->device->errorString());
+            return false;
+        }
+    }
+
+    // Initialize zlib for deflating or inflating.
+
+    // The second argument to inflate/deflateInit2 is the windowBits parameter,
+    // which also controls what kind of compression stream headers to use.
+    // The default value for this is 15. Passing a value greater than 15
+    // enables gzip headers and then subtracts 16 form the windowBits value.
+    // (So passing 31 gives gzip headers and 15 windowBits). Passing a negative
+    // value selects no headers hand then negates the windowBits argument.
+    int windowBits;
+    switch (d->streamFormat) {
+    case QtIOCompressor::GzipFormat:
+        windowBits = 31;
+        break;
+    case QtIOCompressor::RawZipFormat:
+        windowBits = -15;
+        break;
+    default:
+        windowBits = 15;
+    }
+
+    int status;
+    if (read) {
+        d->state = QtIOCompressorPrivate::NotReadFirstByte;
+        d->zlibStream.avail_in = 0;
+        d->zlibStream.next_in = 0;
+        if (d->streamFormat == QtIOCompressor::ZlibFormat) {
+            status = inflateInit(&d->zlibStream);
+        } else {
+            if (checkGzipSupport(zlibVersion()) == false) {
+                setErrorString(QT_TRANSLATE_NOOP("QtIOCompressor::open", "The gzip format not supported in this version of zlib."));
+                return false;
+            }
+
+            status = inflateInit2(&d->zlibStream, windowBits);
+        }
+    } else {
+        d->state = QtIOCompressorPrivate::NoBytesWritten;
+        if (d->streamFormat == QtIOCompressor::ZlibFormat)
+            status = deflateInit(&d->zlibStream, d->compressionLevel);
+        else
+            status = deflateInit2(&d->zlibStream, d->compressionLevel, Z_DEFLATED, windowBits, 8, Z_DEFAULT_STRATEGY);
+    }
+
+    // Handle error.
+    if (status != Z_OK) {
+        d->setZlibError(QT_TRANSLATE_NOOP("QtIOCompressor::open", "Internal zlib error: "), status);
+        return false;
+    }
+    return QIODevice::open(mode);
+}
+
+/*!
+     Closes the QtIOCompressor, and also the underlying device if it was opened by QtIOCompressor.
+    \sa open()
+*/
+void QtIOCompressor::close()
+{
+    Q_D(QtIOCompressor);
+    if (isOpen() == false)
+        return;
+
+    // Flush and close the zlib stream.
+    if (openMode() & ReadOnly) {
+        d->state = QtIOCompressorPrivate::NotReadFirstByte;
+        inflateEnd(&d->zlibStream);
+    } else {
+        if (d->state == QtIOCompressorPrivate::BytesWritten) { // Only flush if we have written anything.
+            d->state = QtIOCompressorPrivate::NoBytesWritten;
+            d->flushZlib(Z_FINISH);
+        }
+        deflateEnd(&d->zlibStream);
+    }
+
+    // Close the underlying device if we are managing it.
+    if (d->manageDevice)
+        d->device->close();
+
+    QIODevice::close();
+}
+
+/*!
+    Flushes the internal buffer.
+
+    Each time you call flush, all data written to the QtIOCompressor is compressed and written to the
+    underlying device. Calling this function can reduce the compression ratio. The underlying device
+    is not flushed.
+
+    Calling this function when QtIOCompressor is in ReadOnly mode has no effect.
+*/
+void QtIOCompressor::flush()
+{
+    Q_D(QtIOCompressor);
+    if (isOpen() == false || openMode() & ReadOnly)
+        return;
+
+    d->flushZlib(Z_SYNC_FLUSH);
+}
+
+/*!
+    Returns 1 if there might be data available for reading, or 0 if there is no data available.
+
+    There is unfortunately no way of knowing how much data there is available when dealing with compressed streams.
+
+    Also, since the remaining compressed data might be a part of the meta-data that ends the compressed stream (and
+    therefore will yield no uncompressed data), you cannot assume that a read after getting a 1 from this function will return data.
+*/
+qint64 QtIOCompressor::bytesAvailable() const
+{
+    Q_D(const QtIOCompressor);
+    if ((openMode() & ReadOnly) == false)
+        return 0;
+
+    int numBytes = 0;
+
+    switch (d->state) {
+        case QtIOCompressorPrivate::NotReadFirstByte:
+            numBytes = d->device->bytesAvailable();
+        break;
+        case QtIOCompressorPrivate::InStream:
+            numBytes = 1;
+        break;
+        case QtIOCompressorPrivate::EndOfStream:
+        case QtIOCompressorPrivate::Error:
+        default:
+            numBytes = 0;
+        break;
+    };
+
+    numBytes += QIODevice::bytesAvailable();
+
+    if (numBytes > 0)
+        return 1;
+    else
+        return 0;
+}
+
+/*!
+    \internal
+    Reads and decompresses data from the underlying device.
+*/
+qint64 QtIOCompressor::readData(char *data, qint64 maxSize)
+{
+    Q_D(QtIOCompressor);
+
+    if (d->state == QtIOCompressorPrivate::EndOfStream)
+        return 0;
+
+    if (d->state == QtIOCompressorPrivate::Error)
+        return -1;
+
+    // We are ging to try to fill the data buffer
+    d->zlibStream.next_out = reinterpret_cast<ZlibByte *>(data);
+    d->zlibStream.avail_out = maxSize;
+
+    int status;
+    do {
+        // Read data if if the input buffer is empty. There could be data in the buffer
+        // from a previous readData call.
+        if (d->zlibStream.avail_in == 0) {
+            qint64 bytesAvalible = d->device->read(reinterpret_cast<char *>(d->buffer), d->bufferSize);
+            d->zlibStream.next_in = d->buffer;
+            d->zlibStream.avail_in = bytesAvalible;
+
+            if (bytesAvalible == -1) {
+                d->state = QtIOCompressorPrivate::Error;
+                setErrorString(QT_TRANSLATE_NOOP("QtIOCompressor", "Error reading data from underlying device: ") + d->device->errorString());
+                return -1;
+            }
+
+            if (d->state != QtIOCompressorPrivate::InStream) {
+                // If we are not in a stream and get 0 bytes, we are probably trying to read from an empty device.
+                if(bytesAvalible == 0)
+                    return 0;
+                else if (bytesAvalible > 0)
+                    d->state = QtIOCompressorPrivate::InStream;
+            }
+        }
+
+        // Decompress.
+        status = inflate(&d->zlibStream, Z_SYNC_FLUSH);
+        switch (status) {
+            case Z_NEED_DICT:
+            case Z_DATA_ERROR:
+            case Z_MEM_ERROR:
+                d->state = QtIOCompressorPrivate::Error;
+                d->setZlibError(QT_TRANSLATE_NOOP("QtIOCompressor", "Internal zlib error when decompressing: "), status);
+                return -1;
+            case Z_BUF_ERROR: // No more input and zlib can not privide more output - Not an error, we can try to read again when we have more input.
+                return 0;
+            break;
+        }
+    // Loop util data buffer is full or we reach the end of the input stream.
+    } while (d->zlibStream.avail_out != 0 && status != Z_STREAM_END);
+
+    if (status == Z_STREAM_END) {
+        d->state = QtIOCompressorPrivate::EndOfStream;
+
+        // Unget any data left in the read buffer.
+        for (int i = d->zlibStream.avail_in;  i >= 0; --i)
+            d->device->ungetChar(*reinterpret_cast<char *>(d->zlibStream.next_in + i));
+    }
+
+    const ZlibSize outputSize = maxSize - d->zlibStream.avail_out;
+    return outputSize;
+}
+
+
+/*!
+    \internal
+    Compresses and writes data to the underlying device.
+*/
+qint64 QtIOCompressor::writeData(const char *data, qint64 maxSize)
+{
+    if (maxSize < 1)
+        return 0;
+    Q_D(QtIOCompressor);
+    d->zlibStream.next_in = reinterpret_cast<ZlibByte *>(const_cast<char *>(data));
+    d->zlibStream.avail_in = maxSize;
+
+    if (d->state == QtIOCompressorPrivate::Error)
+        return -1;
+
+    do {
+        d->zlibStream.next_out = d->buffer;
+        d->zlibStream.avail_out = d->bufferSize;
+        const int status = deflate(&d->zlibStream, Z_NO_FLUSH);
+        if (status != Z_OK) {
+            d->state = QtIOCompressorPrivate::Error;
+            d->setZlibError(QT_TRANSLATE_NOOP("QtIOCompressor", "Internal zlib error when compressing: "), status);
+            return -1;
+        }
+
+        ZlibSize outputSize = d->bufferSize - d->zlibStream.avail_out;
+
+        // Try to write data from the buffer to to the underlying device, return -1 on failure.
+        if (d->writeBytes(d->buffer, outputSize) == false)
+            return -1;
+
+    } while (d->zlibStream.avail_out == 0); // run until output is not full.
+    Q_ASSERT(d->zlibStream.avail_in == 0);
+
+    return maxSize;
+}
+
+/*
+    \internal
+    Checks if the run-time zlib version is 1.2.x or higher.
+*/
+bool QtIOCompressor::checkGzipSupport(const char * const versionString)
+{
+    if (strlen(versionString) < 3)
+        return false;
+
+    if (versionString[0] == '0' || (versionString[0] == '1' && (versionString[2] == '0' || versionString[2]  == '1' )))
+        return false;
+
+    return true;
+}

src/streams/qtiocompressor.h

@@ -0,0 +1,94 @@
+/****************************************************************************
+**
+** Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of a Qt Solutions component.
+**
+** Commercial Usage
+** Licensees holding valid Qt Commercial licenses may use this file in
+** accordance with the Qt Solutions Commercial License Agreement provided
+** with the Software or, alternatively, in accordance with the terms
+** contained in a written agreement between you and Nokia.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.1, included in the file LICENSE.NOKIA-LGPL-EXCEPTION
+** in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL-3 included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** Please note Third Party Software included with Qt Solutions may impose
+** additional restrictions and it is the user's responsibility to ensure
+** that they have met the licensing requirements of the GPL, LGPL, or Qt
+** Solutions Commercial license and the relevant license of the Third
+** Party Software they are using.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact Nokia at qt-info@nokia.com.
+**
+****************************************************************************/
+
+#ifndef QTIOCOMPRESSOR_H
+#define QTIOCOMPRESSOR_H
+
+#include <QtCore/QIODevice>
+
+#if defined(Q_WS_WIN)
+#  if !defined(QT_QTIOCOMPRESSOR_EXPORT) && !defined(QT_QTIOCOMPRESSOR_IMPORT)
+#    define QT_QTIOCOMPRESSOR_EXPORT
+#  elif defined(QT_QTIOCOMPRESSOR_IMPORT)
+#    if defined(QT_QTIOCOMPRESSOR_EXPORT)
+#      undef QT_QTIOCOMPRESSOR_EXPORT
+#    endif
+#    define QT_QTIOCOMPRESSOR_EXPORT __declspec(dllimport)
+#  elif defined(QT_QTIOCOMPRESSOR_EXPORT)
+#    undef QT_QTIOCOMPRESSOR_EXPORT
+#    define QT_QTIOCOMPRESSOR_EXPORT __declspec(dllexport)
+#  endif
+#else
+#  define QT_QTIOCOMPRESSOR_EXPORT
+#endif
+
+class QtIOCompressorPrivate;
+class QT_QTIOCOMPRESSOR_EXPORT QtIOCompressor : public QIODevice
+{
+Q_OBJECT
+public:
+enum StreamFormat { ZlibFormat, GzipFormat, RawZipFormat };
+    QtIOCompressor(QIODevice *device, int compressionLevel = 6, int bufferSize = 65500);
+    ~QtIOCompressor();
+    void setStreamFormat(StreamFormat format);
+    StreamFormat streamFormat() const;
+    static bool isGzipSupported();
+    bool isSequential() const;
+    bool open(OpenMode mode);
+    void close();
+    void flush();
+    qint64 bytesAvailable() const;
+protected:
+    qint64 readData(char * data, qint64 maxSize);
+    qint64 writeData(const char * data, qint64 maxSize);
+private:
+    static bool checkGzipSupport(const char * const versionString);
+    QtIOCompressorPrivate *d_ptr;
+    Q_DECLARE_PRIVATE(QtIOCompressor)
+    Q_DISABLE_COPY(QtIOCompressor)
+};
+
+#endif