kis_jpeg_source.cpp

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/*
 *  SPDX-FileCopyrightText: 2009 Adrian Page <adrian@pagenet.plus.com>
 *
 *  SPDX-License-Identifier: GPL-2.0-or-later
 */
 
#include "kis_jpeg_source.h"
 
#include <jerror.h>
 
#include <QIODevice>
 
#include "kis_debug.h"
 
namespace
{
 
const qint64 INPUT_BUFFER_SIZE = 4096;
 
struct KisJPEGSourceManager : public jpeg_source_mgr
{
    QIODevice* input;
    JOCTET* buffer;
    bool anyDataReceived;
};
 
typedef KisJPEGSourceManager* KisJPEGSourceManagerPtr;
 
extern "C"
{
 
void init_source(j_decompress_ptr cinfo)
{
    KisJPEGSourceManagerPtr src = (KisJPEGSourceManagerPtr)cinfo->src;
    src->anyDataReceived = false;
}
 
boolean fill_input_buffer(j_decompress_ptr cinfo)
{
    KisJPEGSourceManagerPtr src = (KisJPEGSourceManagerPtr)cinfo->src;
    qint64 numBytesRead = src->input->read(reinterpret_cast<char*>(src->buffer), INPUT_BUFFER_SIZE);
 
    if (numBytesRead <= 0) {
        if (!src->anyDataReceived)  {
            /* Treat empty input file as fatal error */
            ERREXIT(cinfo, JERR_INPUT_EMPTY);
        }
        WARNMS(cinfo, JWRN_JPEG_EOF);
 
        /* Insert a fake EOI marker */
        src->buffer[0] = (JOCTET)0xFF;
        src->buffer[1] = (JOCTET)JPEG_EOI;
        numBytesRead = 2;
    }
 
    src->next_input_byte = src->buffer;
    src->bytes_in_buffer = numBytesRead;
    src->anyDataReceived = true;
 
    return (boolean)true;
}
 
void skip_input_data(j_decompress_ptr cinfo, long numBytes)
{
    KisJPEGSourceManagerPtr src = (KisJPEGSourceManagerPtr)cinfo->src;
 
    if (numBytes > 0) {
        while (numBytes > (long)src->bytes_in_buffer) {
            numBytes -= (long)src->bytes_in_buffer;
            (void)fill_input_buffer(cinfo);
        }
        src->next_input_byte += (size_t)numBytes;
        src->bytes_in_buffer -= (size_t)numBytes;
    }
}
 
void term_source(j_decompress_ptr cinfo)
{
    Q_UNUSED(cinfo);
}
 
}
}
 
namespace KisJPEGSource
{
 
void setSource(j_decompress_ptr cinfo, QIODevice* inputDevice)
{
    KisJPEGSourceManagerPtr src = 0;
 
    if (cinfo->src == 0) {
        cinfo->src = (struct jpeg_source_mgr*)
                     (*cinfo->mem->alloc_small)((j_common_ptr)cinfo, JPOOL_PERMANENT,
                                                 sizeof(KisJPEGSourceManager));
        src = (KisJPEGSourceManagerPtr)cinfo->src;
        src->buffer = (JOCTET*)
                      (*cinfo->mem->alloc_small)((j_common_ptr)cinfo, JPOOL_PERMANENT,
                                                  INPUT_BUFFER_SIZE*sizeof(JOCTET));
    }
 
    src = (KisJPEGSourceManagerPtr)cinfo->src;
    src->init_source = init_source;
    src->fill_input_buffer = fill_input_buffer;
    src->skip_input_data = skip_input_data;
    src->resync_to_restart = jpeg_resync_to_restart;
    src->term_source = term_source;
    src->input = inputDevice;
    src->bytes_in_buffer = 0;
    src->next_input_byte = 0;
}
 
}