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Branched from the monolithic repo, Qt master branch, at commit
896db169ea224deb96c59ce8af800d019de63f12

1 files changed, 915 insertions, 0 deletions

diff --git a/src/gui/image/qjpeghandler.cpp b/src/gui/image/qjpeghandler.cpp
new file mode 100644
index 0000000000..d57e0c1244
--- /dev/null
+++ b/src/gui/image/qjpeghandler.cpp
@@ -0,0 +1,915 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** 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 LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qjpeghandler_p.h"
+
+#include <qimage.h>
+#include <qvariant.h>
+#include <qvector.h>
+#include <qbuffer.h>
+#include <private/qsimd_p.h>
+
+#include <stdio.h>      // jpeglib needs this to be pre-included
+#include <setjmp.h>
+
+#ifdef FAR
+#undef FAR
+#endif
+
+// including jpeglib.h seems to be a little messy
+extern "C" {
+// mingw includes rpcndr.h but does not define boolean
+#if defined(Q_OS_WIN) && defined(Q_CC_GNU)
+#   if defined(__RPCNDR_H__) && !defined(boolean)
+        typedef unsigned char boolean;
+#       define HAVE_BOOLEAN
+#   endif
+#endif
+
+#define XMD_H           // shut JPEGlib up
+#if defined(Q_OS_UNIXWARE)
+#  define HAVE_BOOLEAN  // libjpeg under Unixware seems to need this
+#endif
+#include <jpeglib.h>
+#ifdef const
+#  undef const          // remove crazy C hackery in jconfig.h
+#endif
+}
+
+QT_BEGIN_NAMESPACE
+
+void QT_FASTCALL convert_rgb888_to_rgb32_C(quint32 *dst, const uchar *src, int len)
+{
+    // Expand 24->32 bpp.
+    for (int i = 0; i < len; ++i) {
+        *dst++ = qRgb(src[0], src[1], src[2]);
+        src += 3;
+    }
+}
+
+typedef void (QT_FASTCALL *Rgb888ToRgb32Converter)(quint32 *dst, const uchar *src, int len);
+
+static Rgb888ToRgb32Converter rgb888ToRgb32ConverterPtr = convert_rgb888_to_rgb32_C;
+
+struct my_error_mgr : public jpeg_error_mgr {
+    jmp_buf setjmp_buffer;
+};
+
+#if defined(Q_C_CALLBACKS)
+extern "C" {
+#endif
+
+static void my_error_exit (j_common_ptr cinfo)
+{
+    my_error_mgr* myerr = (my_error_mgr*) cinfo->err;
+    char buffer[JMSG_LENGTH_MAX];
+    (*cinfo->err->format_message)(cinfo, buffer);
+    qWarning("%s", buffer);
+    longjmp(myerr->setjmp_buffer, 1);
+}
+
+#if defined(Q_C_CALLBACKS)
+}
+#endif
+
+
+static const int max_buf = 4096;
+
+struct my_jpeg_source_mgr : public jpeg_source_mgr {
+    // Nothing dynamic - cannot rely on destruction over longjump
+    QIODevice *device;
+    JOCTET buffer[max_buf];
+    const QBuffer *memDevice;
+
+public:
+    my_jpeg_source_mgr(QIODevice *device);
+};
+
+#if defined(Q_C_CALLBACKS)
+extern "C" {
+#endif
+
+static void qt_init_source(j_decompress_ptr)
+{
+}
+
+static boolean qt_fill_input_buffer(j_decompress_ptr cinfo)
+{
+    my_jpeg_source_mgr* src = (my_jpeg_source_mgr*)cinfo->src;
+    qint64 num_read = 0;
+    if (src->memDevice) {
+        src->next_input_byte = (const JOCTET *)(src->memDevice->data().constData() + src->memDevice->pos());
+        num_read = src->memDevice->data().size() - src->memDevice->pos();
+        src->device->seek(src->memDevice->data().size());
+    } else {
+        src->next_input_byte = src->buffer;
+        num_read = src->device->read((char*)src->buffer, max_buf);
+    }
+    if (num_read <= 0) {
+        // Insert a fake EOI marker - as per jpeglib recommendation
+        src->next_input_byte = src->buffer;
+        src->buffer[0] = (JOCTET) 0xFF;
+        src->buffer[1] = (JOCTET) JPEG_EOI;
+        src->bytes_in_buffer = 2;
+    } else {
+        src->bytes_in_buffer = num_read;
+    }
+#if defined(Q_OS_UNIXWARE)
+    return B_TRUE;
+#else
+    return true;
+#endif
+}
+
+static void qt_skip_input_data(j_decompress_ptr cinfo, long num_bytes)
+{
+    my_jpeg_source_mgr* src = (my_jpeg_source_mgr*)cinfo->src;
+
+    // `dumb' implementation from jpeglib
+
+    /* Just a dumb implementation for now.  Could use fseek() except
+     * it doesn't work on pipes.  Not clear that being smart is worth
+     * any trouble anyway --- large skips are infrequent.
+     */
+    if (num_bytes > 0) {
+        while (num_bytes > (long) src->bytes_in_buffer) {  // Should not happen in case of memDevice
+            num_bytes -= (long) src->bytes_in_buffer;
+            (void) qt_fill_input_buffer(cinfo);
+            /* note we assume that qt_fill_input_buffer will never return false,
+            * so suspension need not be handled.
+            */
+        }
+        src->next_input_byte += (size_t) num_bytes;
+        src->bytes_in_buffer -= (size_t) num_bytes;
+    }
+}
+
+static void qt_term_source(j_decompress_ptr cinfo)
+{
+    my_jpeg_source_mgr* src = (my_jpeg_source_mgr*)cinfo->src;
+    if (!src->device->isSequential())
+        src->device->seek(src->device->pos() - src->bytes_in_buffer);
+}
+
+#if defined(Q_C_CALLBACKS)
+}
+#endif
+
+inline my_jpeg_source_mgr::my_jpeg_source_mgr(QIODevice *device)
+{
+    jpeg_source_mgr::init_source = qt_init_source;
+    jpeg_source_mgr::fill_input_buffer = qt_fill_input_buffer;
+    jpeg_source_mgr::skip_input_data = qt_skip_input_data;
+    jpeg_source_mgr::resync_to_restart = jpeg_resync_to_restart;
+    jpeg_source_mgr::term_source = qt_term_source;
+    this->device = device;
+    memDevice = qobject_cast<QBuffer *>(device);
+    bytes_in_buffer = 0;
+    next_input_byte = buffer;
+}
+
+
+inline static bool read_jpeg_size(int &w, int &h, j_decompress_ptr cinfo)
+{
+    (void) jpeg_calc_output_dimensions(cinfo);
+
+    w = cinfo->output_width;
+    h = cinfo->output_height;
+    return true;
+}
+
+#define HIGH_QUALITY_THRESHOLD 50
+
+inline static bool read_jpeg_format(QImage::Format &format, j_decompress_ptr cinfo)
+{
+
+    bool result = true;
+    switch (cinfo->output_components) {
+    case 1:
+        format = QImage::Format_Indexed8;
+        break;
+    case 3:
+    case 4:
+        format = QImage::Format_RGB32;
+        break;
+    default:
+        result = false;
+        break;
+    }
+    cinfo->output_scanline = cinfo->output_height;
+    return result;
+}
+
+static bool ensureValidImage(QImage *dest, struct jpeg_decompress_struct *info,
+                             const QSize& size)
+{
+    QImage::Format format;
+    switch (info->output_components) {
+    case 1:
+        format = QImage::Format_Indexed8;
+        break;
+    case 3:
+    case 4:
+        format = QImage::Format_RGB32;
+        break;
+    default:
+        return false; // unsupported format
+    }
+
+    if (dest->size() != size || dest->format() != format) {
+        *dest = QImage(size, format);
+
+        if (format == QImage::Format_Indexed8) {
+            dest->setColorCount(256);
+            for (int i = 0; i < 256; i++)
+                dest->setColor(i, qRgb(i,i,i));
+        }
+    }
+
+    return !dest->isNull();
+}
+
+static bool read_jpeg_image(QImage *outImage,
+                            QSize scaledSize, QRect scaledClipRect,
+                            QRect clipRect, int inQuality, j_decompress_ptr info, struct my_error_mgr* err  )
+{
+    if (!setjmp(err->setjmp_buffer)) {
+        // -1 means default quality.
+        int quality = inQuality;
+        if (quality < 0)
+            quality = 75;
+
+        // If possible, merge the scaledClipRect into either scaledSize
+        // or clipRect to avoid doing a separate scaled clipping pass.
+        // Best results are achieved by clipping before scaling, not after.
+        if (!scaledClipRect.isEmpty()) {
+            if (scaledSize.isEmpty() && clipRect.isEmpty()) {
+                // No clipping or scaling before final clip.
+                clipRect = scaledClipRect;
+                scaledClipRect = QRect();
+            } else if (scaledSize.isEmpty()) {
+                // Clipping, but no scaling: combine the clip regions.
+                scaledClipRect.translate(clipRect.topLeft());
+                clipRect = scaledClipRect.intersected(clipRect);
+                scaledClipRect = QRect();
+            } else if (clipRect.isEmpty()) {
+                // No clipping, but scaling: if we can map back to an
+                // integer pixel boundary, then clip before scaling.
+                if ((info->image_width % scaledSize.width()) == 0 &&
+                        (info->image_height % scaledSize.height()) == 0) {
+                    int x = scaledClipRect.x() * info->image_width /
+                            scaledSize.width();
+                    int y = scaledClipRect.y() * info->image_height /
+                            scaledSize.height();
+                    int width = (scaledClipRect.right() + 1) *
+                                info->image_width / scaledSize.width() - x;
+                    int height = (scaledClipRect.bottom() + 1) *
+                                 info->image_height / scaledSize.height() - y;
+                    clipRect = QRect(x, y, width, height);
+                    scaledSize = scaledClipRect.size();
+                    scaledClipRect = QRect();
+                }
+            } else {
+                // Clipping and scaling: too difficult to figure out,
+                // and not a likely use case, so do it the long way.
+            }
+        }
+
+        // Determine the scale factor to pass to libjpeg for quick downscaling.
+        if (!scaledSize.isEmpty()) {
+            if (clipRect.isEmpty()) {
+                info->scale_denom =
+                    qMin(info->image_width / scaledSize.width(),
+                         info->image_height / scaledSize.height());
+            } else {
+                info->scale_denom =
+                    qMin(clipRect.width() / scaledSize.width(),
+                         clipRect.height() / scaledSize.height());
+            }
+            if (info->scale_denom < 2) {
+                info->scale_denom = 1;
+            } else if (info->scale_denom < 4) {
+                info->scale_denom = 2;
+            } else if (info->scale_denom < 8) {
+                info->scale_denom = 4;
+            } else {
+                info->scale_denom = 8;
+            }
+            info->scale_num = 1;
+            if (!clipRect.isEmpty()) {
+                // Correct the scale factor so that we clip accurately.
+                // It is recommended that the clip rectangle be aligned
+                // on an 8-pixel boundary for best performance.
+                while (info->scale_denom > 1 &&
+                       ((clipRect.x() % info->scale_denom) != 0 ||
+                        (clipRect.y() % info->scale_denom) != 0 ||
+                        (clipRect.width() % info->scale_denom) != 0 ||
+                        (clipRect.height() % info->scale_denom) != 0)) {
+                    info->scale_denom /= 2;
+                }
+            }
+        }
+
+        // If high quality not required, use fast decompression
+        if( quality < HIGH_QUALITY_THRESHOLD ) {
+            info->dct_method = JDCT_IFAST;
+            info->do_fancy_upsampling = FALSE;
+        }
+
+        (void) jpeg_calc_output_dimensions(info);
+
+        // Determine the clip region to extract.
+        QRect imageRect(0, 0, info->output_width, info->output_height);
+        QRect clip;
+        if (clipRect.isEmpty()) {
+            clip = imageRect;
+        } else if (info->scale_denom == info->scale_num) {
+            clip = clipRect.intersected(imageRect);
+        } else {
+            // The scale factor was corrected above to ensure that
+            // we don't miss pixels when we scale the clip rectangle.
+            clip = QRect(clipRect.x() / int(info->scale_denom),
+                         clipRect.y() / int(info->scale_denom),
+                         clipRect.width() / int(info->scale_denom),
+                         clipRect.height() / int(info->scale_denom));
+            clip = clip.intersected(imageRect);
+        }
+
+        // Allocate memory for the clipped QImage.
+        if (!ensureValidImage(outImage, info, clip.size()))
+            longjmp(err->setjmp_buffer, 1);
+
+        // Avoid memcpy() overhead if grayscale with no clipping.
+        bool quickGray = (info->output_components == 1 &&
+                          clip == imageRect);
+        if (!quickGray) {
+            // Ask the jpeg library to allocate a temporary row.
+            // The library will automatically delete it for us later.
+            // The libjpeg docs say we should do this before calling
+            // jpeg_start_decompress().  We can't use "new" here
+            // because we are inside the setjmp() block and an error
+            // in the jpeg input stream would cause a memory leak.
+            JSAMPARRAY rows = (info->mem->alloc_sarray)
+                              ((j_common_ptr)info, JPOOL_IMAGE,
+                               info->output_width * info->output_components, 1);
+
+            (void) jpeg_start_decompress(info);
+
+            while (info->output_scanline < info->output_height) {
+                int y = int(info->output_scanline) - clip.y();
+                if (y >= clip.height())
+                    break;      // We've read the entire clip region, so abort.
+
+                (void) jpeg_read_scanlines(info, rows, 1);
+
+                if (y < 0)
+                    continue;   // Haven't reached the starting line yet.
+
+                if (info->output_components == 3) {
+                    uchar *in = rows[0] + clip.x() * 3;
+                    QRgb *out = (QRgb*)outImage->scanLine(y);
+                    rgb888ToRgb32ConverterPtr(out, in, clip.width());
+                } else if (info->out_color_space == JCS_CMYK) {
+                    // Convert CMYK->RGB.
+                    uchar *in = rows[0] + clip.x() * 4;
+                    QRgb *out = (QRgb*)outImage->scanLine(y);
+                    for (int i = 0; i < clip.width(); ++i) {
+                        int k = in[3];
+                        *out++ = qRgb(k * in[0] / 255, k * in[1] / 255,
+                                      k * in[2] / 255);
+                        in += 4;
+                    }
+                } else if (info->output_components == 1) {
+                    // Grayscale.
+                    memcpy(outImage->scanLine(y),
+                           rows[0] + clip.x(), clip.width());
+                }
+            }
+        } else {
+            // Load unclipped grayscale data directly into the QImage.
+            (void) jpeg_start_decompress(info);
+            while (info->output_scanline < info->output_height) {
+                uchar *row = outImage->scanLine(info->output_scanline);
+                (void) jpeg_read_scanlines(info, &row, 1);
+            }
+        }
+
+        if (info->output_scanline == info->output_height)
+            (void) jpeg_finish_decompress(info);
+
+        if (info->density_unit == 1) {
+            outImage->setDotsPerMeterX(int(100. * info->X_density / 2.54));
+            outImage->setDotsPerMeterY(int(100. * info->Y_density / 2.54));
+        } else if (info->density_unit == 2) {
+            outImage->setDotsPerMeterX(int(100. * info->X_density));
+            outImage->setDotsPerMeterY(int(100. * info->Y_density));
+        }
+
+        if (scaledSize.isValid() && scaledSize != clip.size()) {
+            *outImage = outImage->scaled(scaledSize, Qt::IgnoreAspectRatio, quality >= HIGH_QUALITY_THRESHOLD ? Qt::SmoothTransformation : Qt::FastTransformation);
+        }
+
+        if (!scaledClipRect.isEmpty())
+            *outImage = outImage->copy(scaledClipRect);
+        return !outImage->isNull();
+    }
+    else
+        return false;
+}
+
+struct my_jpeg_destination_mgr : public jpeg_destination_mgr {
+    // Nothing dynamic - cannot rely on destruction over longjump
+    QIODevice *device;
+    JOCTET buffer[max_buf];
+
+public:
+    my_jpeg_destination_mgr(QIODevice *);
+};
+
+
+#if defined(Q_C_CALLBACKS)
+extern "C" {
+#endif
+
+static void qt_init_destination(j_compress_ptr)
+{
+}
+
+static boolean qt_empty_output_buffer(j_compress_ptr cinfo)
+{
+    my_jpeg_destination_mgr* dest = (my_jpeg_destination_mgr*)cinfo->dest;
+
+    int written = dest->device->write((char*)dest->buffer, max_buf);
+    if (written == -1)
+        (*cinfo->err->error_exit)((j_common_ptr)cinfo);
+
+    dest->next_output_byte = dest->buffer;
+    dest->free_in_buffer = max_buf;
+
+#if defined(Q_OS_UNIXWARE)
+    return B_TRUE;
+#else
+    return true;
+#endif
+}
+
+static void qt_term_destination(j_compress_ptr cinfo)
+{
+    my_jpeg_destination_mgr* dest = (my_jpeg_destination_mgr*)cinfo->dest;
+    qint64 n = max_buf - dest->free_in_buffer;
+
+    qint64 written = dest->device->write((char*)dest->buffer, n);
+    if (written == -1)
+        (*cinfo->err->error_exit)((j_common_ptr)cinfo);
+}
+
+#if defined(Q_C_CALLBACKS)
+}
+#endif
+
+inline my_jpeg_destination_mgr::my_jpeg_destination_mgr(QIODevice *device)
+{
+    jpeg_destination_mgr::init_destination = qt_init_destination;
+    jpeg_destination_mgr::empty_output_buffer = qt_empty_output_buffer;
+    jpeg_destination_mgr::term_destination = qt_term_destination;
+    this->device = device;
+    next_output_byte = buffer;
+    free_in_buffer = max_buf;
+}
+
+
+static bool write_jpeg_image(const QImage &image, QIODevice *device, int sourceQuality)
+{
+    bool success = false;
+    const QVector<QRgb> cmap = image.colorTable();
+
+    struct jpeg_compress_struct cinfo;
+    JSAMPROW row_pointer[1];
+    row_pointer[0] = 0;
+
+    struct my_jpeg_destination_mgr *iod_dest = new my_jpeg_destination_mgr(device);
+    struct my_error_mgr jerr;
+
+    cinfo.err = jpeg_std_error(&jerr);
+    jerr.error_exit = my_error_exit;
+
+    if (!setjmp(jerr.setjmp_buffer)) {
+        // WARNING:
+        // this if loop is inside a setjmp/longjmp branch
+        // do not create C++ temporaries here because the destructor may never be called
+        // if you allocate memory, make sure that you can free it (row_pointer[0])
+        jpeg_create_compress(&cinfo);
+
+        cinfo.dest = iod_dest;
+
+        cinfo.image_width = image.width();
+        cinfo.image_height = image.height();
+
+        bool gray=false;
+        switch (image.format()) {
+        case QImage::Format_Mono:
+        case QImage::Format_MonoLSB:
+        case QImage::Format_Indexed8:
+            gray = true;
+            for (int i = image.colorCount(); gray && i--;) {
+                gray = gray & (qRed(cmap[i]) == qGreen(cmap[i]) &&
+                               qRed(cmap[i]) == qBlue(cmap[i]));
+            }
+            cinfo.input_components = gray ? 1 : 3;
+            cinfo.in_color_space = gray ? JCS_GRAYSCALE : JCS_RGB;
+            break;
+        default:
+            cinfo.input_components = 3;
+            cinfo.in_color_space = JCS_RGB;
+        }
+
+        jpeg_set_defaults(&cinfo);
+
+        qreal diffInch = qAbs(image.dotsPerMeterX()*2.54/100. - qRound(image.dotsPerMeterX()*2.54/100.))
+                         + qAbs(image.dotsPerMeterY()*2.54/100. - qRound(image.dotsPerMeterY()*2.54/100.));
+        qreal diffCm = (qAbs(image.dotsPerMeterX()/100. - qRound(image.dotsPerMeterX()/100.))
+                        + qAbs(image.dotsPerMeterY()/100. - qRound(image.dotsPerMeterY()/100.)))*2.54;
+        if (diffInch < diffCm) {
+            cinfo.density_unit = 1; // dots/inch
+            cinfo.X_density = qRound(image.dotsPerMeterX()*2.54/100.);
+            cinfo.Y_density = qRound(image.dotsPerMeterY()*2.54/100.);
+        } else {
+            cinfo.density_unit = 2; // dots/cm
+            cinfo.X_density = (image.dotsPerMeterX()+50) / 100;
+            cinfo.Y_density = (image.dotsPerMeterY()+50) / 100;
+        }
+
+
+        int quality = sourceQuality >= 0 ? qMin(sourceQuality,100) : 75;
+#if defined(Q_OS_UNIXWARE)
+        jpeg_set_quality(&cinfo, quality, B_TRUE /* limit to baseline-JPEG values */);
+        jpeg_start_compress(&cinfo, B_TRUE);
+#else
+        jpeg_set_quality(&cinfo, quality, true /* limit to baseline-JPEG values */);
+        jpeg_start_compress(&cinfo, true);
+#endif
+
+        row_pointer[0] = new uchar[cinfo.image_width*cinfo.input_components];
+        int w = cinfo.image_width;
+        while (cinfo.next_scanline < cinfo.image_height) {
+            uchar *row = row_pointer[0];
+            switch (image.format()) {
+            case QImage::Format_Mono:
+            case QImage::Format_MonoLSB:
+                if (gray) {
+                    const uchar* data = image.constScanLine(cinfo.next_scanline);
+                    if (image.format() == QImage::Format_MonoLSB) {
+                        for (int i=0; i<w; i++) {
+                            bool bit = !!(*(data + (i >> 3)) & (1 << (i & 7)));
+                            row[i] = qRed(cmap[bit]);
+                        }
+                    } else {
+                        for (int i=0; i<w; i++) {
+                            bool bit = !!(*(data + (i >> 3)) & (1 << (7 -(i & 7))));
+                            row[i] = qRed(cmap[bit]);
+                        }
+                    }
+                } else {
+                    const uchar* data = image.constScanLine(cinfo.next_scanline);
+                    if (image.format() == QImage::Format_MonoLSB) {
+                        for (int i=0; i<w; i++) {
+                            bool bit = !!(*(data + (i >> 3)) & (1 << (i & 7)));
+                            *row++ = qRed(cmap[bit]);
+                            *row++ = qGreen(cmap[bit]);
+                            *row++ = qBlue(cmap[bit]);
+                        }
+                    } else {
+                        for (int i=0; i<w; i++) {
+                            bool bit = !!(*(data + (i >> 3)) & (1 << (7 -(i & 7))));
+                            *row++ = qRed(cmap[bit]);
+                            *row++ = qGreen(cmap[bit]);
+                            *row++ = qBlue(cmap[bit]);
+                        }
+                    }
+                }
+                break;
+            case QImage::Format_Indexed8:
+                if (gray) {
+                    const uchar* pix = image.constScanLine(cinfo.next_scanline);
+                    for (int i=0; i<w; i++) {
+                        *row = qRed(cmap[*pix]);
+                        ++row; ++pix;
+                    }
+                } else {
+                    const uchar* pix = image.constScanLine(cinfo.next_scanline);
+                    for (int i=0; i<w; i++) {
+                        *row++ = qRed(cmap[*pix]);
+                        *row++ = qGreen(cmap[*pix]);
+                        *row++ = qBlue(cmap[*pix]);
+                        ++pix;
+                    }
+                }
+                break;
+            case QImage::Format_RGB888:
+                memcpy(row, image.constScanLine(cinfo.next_scanline), w * 3);
+                break;
+            case QImage::Format_RGB32:
+            case QImage::Format_ARGB32:
+            case QImage::Format_ARGB32_Premultiplied:
+                {
+                    const QRgb* rgb = (const QRgb*)image.constScanLine(cinfo.next_scanline);
+                    for (int i=0; i<w; i++) {
+                        *row++ = qRed(*rgb);
+                        *row++ = qGreen(*rgb);
+                        *row++ = qBlue(*rgb);
+                        ++rgb;
+                    }
+                }
+                break;
+            default:
+                {
+                    // (Testing shows that this way is actually faster than converting to RGB888 + memcpy)
+                    QImage rowImg = image.copy(0, cinfo.next_scanline, w, 1).convertToFormat(QImage::Format_RGB32);
+                    const QRgb* rgb = (const QRgb*)rowImg.constScanLine(0);
+                    for (int i=0; i<w; i++) {
+                        *row++ = qRed(*rgb);
+                        *row++ = qGreen(*rgb);
+                        *row++ = qBlue(*rgb);
+                        ++rgb;
+                    }
+                }
+                break;
+            }
+            jpeg_write_scanlines(&cinfo, row_pointer, 1);
+        }
+
+        jpeg_finish_compress(&cinfo);
+        jpeg_destroy_compress(&cinfo);
+        success = true;
+    } else {
+        jpeg_destroy_compress(&cinfo);
+        success = false;
+    }
+
+    delete iod_dest;
+    delete [] row_pointer[0];
+    return success;
+}
+
+class QJpegHandlerPrivate
+{
+public:
+    enum State {
+        Ready,
+        ReadHeader,
+        Error
+    };
+
+    QJpegHandlerPrivate(QJpegHandler *qq)
+        : quality(75), iod_src(0), state(Ready), q(qq)
+    {}
+
+    ~QJpegHandlerPrivate()
+    {
+        if(iod_src)
+        {
+            jpeg_destroy_decompress(&info);
+            delete iod_src;
+            iod_src = 0;
+        }
+    }
+
+    bool readJpegHeader(QIODevice*);
+    bool read(QImage *image);
+
+    int quality;
+    QVariant size;
+    QImage::Format format;
+    QSize scaledSize;
+    QRect scaledClipRect;
+    QRect clipRect;
+    struct jpeg_decompress_struct info;
+    struct my_jpeg_source_mgr * iod_src;
+    struct my_error_mgr err;
+
+    State state;
+
+    QJpegHandler *q;
+};
+
+/*!
+    \internal
+*/
+bool QJpegHandlerPrivate::readJpegHeader(QIODevice *device)
+{
+    if(state == Ready)
+    {
+        state = Error;
+        iod_src = new my_jpeg_source_mgr(device);
+
+        jpeg_create_decompress(&info);
+        info.src = iod_src;
+        info.err = jpeg_std_error(&err);
+        err.error_exit = my_error_exit;
+
+        if (!setjmp(err.setjmp_buffer)) {
+    #if defined(Q_OS_UNIXWARE)
+            (void) jpeg_read_header(&info, B_TRUE);
+    #else
+            (void) jpeg_read_header(&info, true);
+    #endif
+
+            int width = 0;
+            int height = 0;
+            read_jpeg_size(width, height, &info);
+            size = QSize(width, height);
+
+            format = QImage::Format_Invalid;
+            read_jpeg_format(format, &info);
+            state = ReadHeader;
+            return true;
+        }
+        else
+        {
+            return false;
+        }
+    }
+    else if(state == Error)
+        return false;
+    return true;
+}
+
+bool QJpegHandlerPrivate::read(QImage *image)
+{
+    if(state == Ready)
+        readJpegHeader(q->device());
+
+    if(state == ReadHeader)
+    {
+        bool success = read_jpeg_image(image, scaledSize, scaledClipRect, clipRect, quality,  &info, &err);
+        state = success ? Ready : Error;
+        return success;
+    }
+
+    return false;
+
+}
+
+QJpegHandler::QJpegHandler()
+    : d(new QJpegHandlerPrivate(this))
+{
+    const uint features = qDetectCPUFeatures();
+    Q_UNUSED(features);
+#if defined(QT_HAVE_NEON)
+    // from qimage_neon.cpp
+    Q_GUI_EXPORT void QT_FASTCALL qt_convert_rgb888_to_rgb32_neon(quint32 *dst, const uchar *src, int len);
+
+    if (features & NEON)
+        rgb888ToRgb32ConverterPtr = qt_convert_rgb888_to_rgb32_neon;
+#endif // QT_HAVE_NEON
+#if defined(QT_HAVE_SSSE3)
+    // from qimage_ssse3.cpp
+    Q_GUI_EXPORT void QT_FASTCALL qt_convert_rgb888_to_rgb32_ssse3(quint32 *dst, const uchar *src, int len);
+
+    if (features & SSSE3)
+        rgb888ToRgb32ConverterPtr = qt_convert_rgb888_to_rgb32_ssse3;
+#endif // QT_HAVE_SSSE3
+}
+
+QJpegHandler::~QJpegHandler()
+{
+    delete d;
+}
+
+bool QJpegHandler::canRead() const
+{
+    if(d->state == QJpegHandlerPrivate::Ready && !canRead(device()))
+        return false;
+
+    if (d->state != QJpegHandlerPrivate::Error) {
+        setFormat("jpeg");
+        return true;
+    }
+
+    return false;
+}
+
+bool QJpegHandler::canRead(QIODevice *device)
+{
+    if (!device) {
+        qWarning("QJpegHandler::canRead() called with no device");
+        return false;
+    }
+
+    char buffer[2];
+    if (device->peek(buffer, 2) != 2)
+        return false;
+    return uchar(buffer[0]) == 0xff && uchar(buffer[1]) == 0xd8;
+}
+
+bool QJpegHandler::read(QImage *image)
+{
+    if (!canRead())
+        return false;
+    return d->read(image);
+}
+
+bool QJpegHandler::write(const QImage &image)
+{
+    return write_jpeg_image(image, device(), d->quality);
+}
+
+bool QJpegHandler::supportsOption(ImageOption option) const
+{
+    return option == Quality
+        || option == ScaledSize
+        || option == ScaledClipRect
+        || option == ClipRect
+        || option == Size
+        || option == ImageFormat;
+}
+
+QVariant QJpegHandler::option(ImageOption option) const
+{
+    switch(option) {
+    case Quality:
+        return d->quality;
+    case ScaledSize:
+        return d->scaledSize;
+    case ScaledClipRect:
+        return d->scaledClipRect;
+    case ClipRect:
+        return d->clipRect;
+    case Size:
+        d->readJpegHeader(device());
+        return d->size;
+    case ImageFormat:
+        d->readJpegHeader(device());
+        return d->format;
+    default:
+        return QVariant();
+    }
+}
+
+void QJpegHandler::setOption(ImageOption option, const QVariant &value)
+{
+    switch(option) {
+    case Quality:
+        d->quality = value.toInt();
+        break;
+    case ScaledSize:
+        d->scaledSize = value.toSize();
+        break;
+    case ScaledClipRect:
+        d->scaledClipRect = value.toRect();
+        break;
+    case ClipRect:
+        d->clipRect = value.toRect();
+        break;
+    default:
+        break;
+    }
+}
+
+QByteArray QJpegHandler::name() const
+{
+    return "jpeg";
+}
+
+
+
+
+QT_END_NAMESPACE