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** contained in the Technology Preview License Agreement accompanying

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** General Public License version 2.1 as published by the Free Software

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****************************************************************************/

#include "qjpeghandler_p.h"

#include <qimage.h>

#include <qvariant.h>

#include <qvector.h>

#include <qbuffer.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

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;

    if (src->memDevice) {

        src->next_input_byte = (const JOCTET *)(src->memDevice->data().constData() + src->memDevice->pos());

        src->bytes_in_buffer = (size_t)(src->memDevice->data().size() - src->memDevice->pos());

        return true;

    }

    src->next_input_byte = src->buffer;

    int num_read = src->device->read((char*)src->buffer, max_buf);

    if (num_read <= 0) {

        // Insert a fake EOI marker - as per jpeglib recommendation

        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())

    {

        // read() isn't used for memDevice, so seek past everything that was used

        if (src->memDevice)

            src->device->seek(src->device->pos() + (src->memDevice->data().size() - src->memDevice->pos() - src->bytes_in_buffer));

        else

            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) {

                    // Expand 24->32 bpp.

                    uchar *in = rows[0] + clip.x() * 3;

                    QRgb *out = (QRgb*)outImage->scanLine(y);

                    for (int i = 0; i < clip.width(); ++i) {

                        *out++ = qRgb(in[0], in[1], in[2]);

                        in += 3;

                    }

                } 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 can_write_format(QImage::Format fmt)

{

    switch (fmt) {

    case QImage::Format_Mono:

    case QImage::Format_MonoLSB:

    case QImage::Format_Indexed8:

    case QImage::Format_RGB888:

    case QImage::Format_RGB32:

    case QImage::Format_ARGB32:

    case QImage::Format_ARGB32_Premultiplied:

        return true;

        break;

    default:

        break;

    }

    return false;

}