/*
 *
 *  Copyright (C) 2007-2022, OFFIS e.V.
 *  All rights reserved.  See COPYRIGHT file for details.
 *
 *  This software and supporting documentation were developed by
 *
 *    OFFIS e.V.
 *    R&D Division Health
 *    Escherweg 2
 *    D-26121 Oldenburg, Germany
 *
 *
 *  Module:  dcmdata
 *
 *  Author:  Michael Onken
 *
 *  Purpose: Class to extract pixel data and meta information from JPEG file
 *
 */

#include "dcmtk/dcmdata/libi2d/i2djpgs.h"
#include "dcmtk/config/osconfig.h"
#include "dcmtk/dcmdata/dcerror.h"
#include "dcmtk/dcmdata/libi2d/i2doutpl.h"

I2DJpegSource::I2DJpegSource()
    : m_jpegFileMap()
    , jpegFile()
    , m_disableProgrTs(OFFalse)
    , m_disableExtSeqTs(OFFalse)
    , m_insistOnJFIF(OFFalse)
    , m_keepAPPn(OFFalse)
    , m_keepCOM(OFTrue)
    , m_lossyCompressed(OFTrue)
    , m_isJPEGLS(OFFalse)
{
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Plugin instantiated");
}

OFString I2DJpegSource::inputFormat() const
{
    return "JPEG";
}

OFCondition I2DJpegSource::openFile(const OFString& filename)
{
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Opening JPEG file: " << filename);
    OFCondition cond;
    if (filename.empty())
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "No JPEG filename specified");

    // Try to open JPEG file
    if ((jpegFile.fopen(filename.c_str(), "rb")) == OFFalse)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Unable to open JPEG file");

    return cond;
}

void I2DJpegSource::setExtSeqSupport(const OFBool enabled)
{
    m_disableExtSeqTs = !enabled;
}

void I2DJpegSource::setProgrSupport(const OFBool enabled)
{
    m_disableProgrTs = !enabled;
}

void I2DJpegSource::setInsistOnJFIF(const OFBool enabled)
{
    m_insistOnJFIF = enabled;
}

void I2DJpegSource::setKeepAPPn(const OFBool enabled)
{
    m_keepAPPn = enabled;
}

void I2DJpegSource::setKeepCOM(const OFBool enabled)
{
    m_keepCOM = enabled;
}

OFCondition I2DJpegSource::readPixelData(Uint16& rows,
                                         Uint16& cols,
                                         Uint16& samplesPerPixel,
                                         OFString& photoMetrInt,
                                         Uint16& bitsAlloc,
                                         Uint16& bitsStored,
                                         Uint16& highBit,
                                         Uint16& pixelRepr,
                                         Uint16& planConf,
                                         Uint16& pixAspectH,
                                         Uint16& pixAspectV,
                                         char*& pixData,
                                         Uint32& length,
                                         E_TransferSyntax& ts)
{
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Importing JPEG pixel data");
    OFCondition cond = openFile(m_imageFile);
    // return error if file is not open
    if (cond.bad())
    {
        closeFile();
        return cond;
    }
    // Create "map" with byte positions of all JPEG markers in JPEG file
    cond = createJPEGFileMap();
    if (cond.bad())
    {
        clearMap();
        closeFile();
        return cond;
    }

    // for JPEG-LS retrieve SOS (nearLossless value)
    Uint8 nearLossless = 0;
    if( m_isJPEGLS )
    {
        OFListIterator(JPEGFileMapEntry*) entry = m_jpegFileMap.begin();
        OFListIterator(JPEGFileMapEntry*) entrySos = m_jpegFileMap.end();
        OFListIterator(JPEGFileMapEntry*) entryApp8 = m_jpegFileMap.end();
        while (entry != m_jpegFileMap.end())
        {
            if ((*entry)->marker == E_JPGMARKER_SOS)
            {
                if( entrySos == m_jpegFileMap.end() )
                  entrySos = entry;
            }
            else if ((*entry)->marker == E_JPGMARKER_APP8)
            {
                if( entryApp8 == m_jpegFileMap.end() )
                  entryApp8 = entry;
            }
            entry++;
        }
        if (entrySos == m_jpegFileMap.end())
        {
            closeFile();
            return makeOFCondition(OFM_dcmdata, 18, OF_error, "No start-of-scan marker found in JPEG-LS file");
        }
        cond = getSOSImageParameters(**entrySos, nearLossless);
        if (cond.bad())
        {
            closeFile();
            return cond;
        }
        m_lossyCompressed = (nearLossless >= 1 ? OFTrue : OFFalse);

        // APP8 marker was found, check if this is one of the accepted HP transform ones
        if (entryApp8 != m_jpegFileMap.end())
        {
            Uint8 xform = 0;
            cond = getAPP8ImageParameters(**entryApp8, xform);
            if (cond.bad())
            {
                closeFile();
                return cond;
            }
            if(xform != 0)
            {
                closeFile();
                return makeOFCondition(OFM_dcmdata, 18, OF_error, "APP8 marker contained invalid color transform.");
            }
        }
    }

    // Check for image data in file (look for SOF marker)
    E_JPGMARKER jpegEncoding;
    OFListIterator(JPEGFileMapEntry*) entry = m_jpegFileMap.begin();
    while (entry != m_jpegFileMap.end())
    {
        if (isSOFMarker((*entry)->marker, m_isJPEGLS))
        {
            jpegEncoding = OFstatic_cast(E_JPGMARKER, (*entry)->marker);
            break;
        }
        entry++;
    }
    if (entry == m_jpegFileMap.end())
    {
        closeFile();
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "No image data found in JPEG file");
    }

    // Reject arithmetic and hierarchical (differential) encodings (not supported)
    cond = isJPEGEncodingSupported(jpegEncoding);
    if (cond.bad())
    {
        closeFile();
        return cond;
    }

    // Get transfer syntax associated with the given JPEG encoding
    ts = associatedTS(jpegEncoding, m_isJPEGLS, nearLossless);

    // Extract width, height, samples per pixel, bits per sample
    Uint16 width, height, spp, bps;
    cond = getSOFImageParameters(**entry, width, height, spp, bps);
    if (cond.bad())
    {
        closeFile();
        return cond;
    }

    // Return error if invalid image attributes were found
    if (height == 0 || width == 0)
    {
        closeFile();
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Invalid image size (width or height = 0)");
    }

    // Examine JFIF information (version, horizontal and vertical aspect ratio, aspect ratio units.
    Uint16 jfifVersion, unit;
    Uint16 aspectH = 1;
    Uint16 aspectV = 1;
    entry          = m_jpegFileMap.begin();
    while (entry != m_jpegFileMap.end())
    {
        if ((*entry)->marker == E_JPGMARKER_APP0)
            break;
        entry++;
    }
    if (entry == m_jpegFileMap.end())
    {
        if (!m_insistOnJFIF)
        {
            DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Ignoring missing JFIF header");
        }
        else
        {
            closeFile();
            return makeOFCondition(OFM_dcmdata, 18, OF_error, "No JFIF information found in JPEG file");
        }
    }
    else
        cond = getJFIFImageParameters(**entry, jfifVersion, aspectH, aspectV, unit);
    if (cond.bad())
    {
        if (!m_insistOnJFIF)
        {
            DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Ignoring errors while evaluating JFIF data");
        }
        else
        {
            closeFile();
            return cond;
        }
    }
    pixAspectH = aspectH;
    pixAspectV = aspectV;

    // Collect information needed for image pixel module
    rows            = height;
    cols            = width;
    samplesPerPixel = spp;
    bitsStored      = bps;
    bitsAlloc       = bps;

    // When BitsStored = 12, we use BitsAllocated = 16
    if (bitsAlloc == 12)
    {
        bitsAlloc = 16;
    }

    // HighBit is always BitsStored - 1.
    highBit = bitsStored;
    highBit--;

    if (samplesPerPixel == 1)
        photoMetrInt = "MONOCHROME2";
    else if (samplesPerPixel == 3)
    {
        if (m_isJPEGLS)
          photoMetrInt = "RGB";
        else
          photoMetrInt = "YBR_FULL_422";
    }
    else
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "For JPEG data, Samples per Pixel must be 1 or 3");
    // Planar Configuration and Pixel Representation is always 0 for JPEG data
    planConf  = 0;
    pixelRepr = 0;

    Uint32 tLength   = 0;
    char* tPixelData = NULL;
    cond             = extractRawJPEGStream(tPixelData, tLength);
    if (cond.bad())
    {
        closeFile();
        return cond;
    }
    length  = tLength;
    pixData = tPixelData;
    return cond;
}

OFCondition I2DJpegSource::getLossyComprInfo(OFBool& srcEncodingLossy, OFString& srcLossyComprMethod) const
{
    if (m_lossyCompressed)
    {
        srcEncodingLossy    = OFTrue;
        if (m_isJPEGLS)
          srcLossyComprMethod = "ISO_14495_1"; // Defined term for JPEG-LS Lossy Compression
        else
          srcLossyComprMethod = "ISO_10918_1"; // Defined term for JPEG Lossy Compression
    }
    else
    {
        // (will never get here, no lossless input supported so far)
        srcEncodingLossy = OFFalse;
    }
    return EC_Normal;
}

OFCondition I2DJpegSource::getSOFImageParameters(const JPEGFileMapEntry& entry,
                                                 Uint16& imageWidth,
                                                 Uint16& imageHeight,
                                                 Uint16& samplesPerPixel,
                                                 Uint16& bitsPerSample)
{
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Examining JPEG SOF image parameters");
    if (!isSOFMarker(entry.marker, m_isJPEGLS))
        return EC_IllegalCall;
    Uint16 length;
    Uint16 image_height, image_width;
    Uint8 data_precision, num_components;
    int result;

    // seek to the given SOFn marker

    jpegFile.fseek(entry.bytePos, SEEK_SET);
    result = read2Bytes(length); /* usual parameter length count */
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");

    // read values

    result = read1Byte(data_precision);
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");

    result = read2Bytes(image_height);
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");

    result = read2Bytes(image_width);
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");

    result = read1Byte(num_components);
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");

    imageWidth      = image_width;
    imageHeight     = image_height;
    samplesPerPixel = num_components;
    bitsPerSample   = data_precision;

    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Dumping JPEG SOF image parameters:");
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource:   Image Width: " << image_width);
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource:   Image Height: " << image_height);
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource:   Number of Components: " << OFstatic_cast(unsigned int, num_components));
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource:   Data Precision: " << OFstatic_cast(unsigned int, data_precision));

    if (length != OFstatic_cast(unsigned int, 8 + num_components * 3))
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Bogus SOF marker length");

    return EC_Normal;
}

OFCondition I2DJpegSource::getSOSImageParameters(const JPEGFileMapEntry& entry,
                                                 Uint8& nearLossless)
{
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Examining JPEG SOS image parameters");
    if (entry.marker != E_JPGMARKER_SOS)
        return EC_IllegalCall;
    Uint16 length;
    Uint8 component_count_in_scan;
    Uint8 near_lossless;
    int result;

    // seek to the given SOFn marker

    jpegFile.fseek(entry.bytePos, SEEK_SET);
    result = read2Bytes(length); /* usual parameter length count */
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");

    // read values

    result = read1Byte(component_count_in_scan);
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");

    jpegFile.fseek(2 * component_count_in_scan, SEEK_CUR);

    result = read1Byte(near_lossless);
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");

    nearLossless = near_lossless;

    DCMDATA_LIBI2D_DEBUG("I2DJpegLsSource: Dumping JPEG SOS image parameters:");
    DCMDATA_LIBI2D_DEBUG("I2DJpegLsSource:   nComponentsPerScan: " << OFstatic_cast(unsigned int, component_count_in_scan));
    DCMDATA_LIBI2D_DEBUG("I2DJpegLsSource:   Near Lossless: " << OFstatic_cast(unsigned int, near_lossless));

    if (length != OFstatic_cast(unsigned int, 6 + component_count_in_scan * 2))
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Bogus SOS marker length");

    return EC_Normal;
}

OFCondition I2DJpegSource::getAPP8ImageParameters(const JPEGFileMapEntry& entry, Uint8& xform)
{
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Examining JPEG APP8 parameters");
    if (entry.marker != E_JPGMARKER_APP8)
        return EC_IllegalCall;
    Uint16 length;
    Uint8 mrfx[4];
    int result;

    // seek to the given SOFn marker

    jpegFile.fseek(entry.bytePos, SEEK_SET);
    result = read2Bytes(length); /* usual parameter length count */
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");

    if(length != 7)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "APP8 marker found. Only handle 'mrfx'");

    // read values
    for(int i = 0; i < 4; ++i )
    {
      result = read1Byte(mrfx[i]);
      if (result == EOF)
          return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");
    }

    if(memcmp(mrfx,"mrfx", 4) != 0)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "APP8 marker found. Only handle 'mrfx'");

    result = read1Byte(xform);
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");

    return EC_Normal;
}

// ignores thumbnail data
OFCondition I2DJpegSource::getJFIFImageParameters(
    const JPEGFileMapEntry& entry, Uint16& jfifVersion, Uint16& pixelAspectH, Uint16& pixelAspectV, Uint16& unit)
{
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Examining JFIF information");
    if (entry.marker != E_JPGMARKER_APP0)
        return EC_IllegalCall;
    Uint16 jv, pah, pav, unt;

    // go to specified byte position and read on to value field
    Uint16 length;
    jpegFile.fseek(entry.bytePos, SEEK_SET);
    int result = read2Bytes(length); /* usual parameter length count */
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");

    // read and check the 5 byte "JFIF" marker value (X'4A', X'46', X'49', X'46', X'00')
    Uint16 twoBytes;
    result = read2Bytes(twoBytes);
    if ((result == EOF) || (twoBytes != 0x4a46))
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Invalid JFIF marker or JFIF marker not found");
    result = read2Bytes(twoBytes);
    if ((result == EOF) || (twoBytes != 0x4946))
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Invalid JFIF marker or JFIF marker not found");
    Uint8 oneByte;
    result = read1Byte(oneByte);
    if ((result == EOF) || (oneByte != 0x00))
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Invalid JFIF marker or JFIF marker not found");

    // read JFIF version
    result = read2Bytes(twoBytes);
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");
    jv = twoBytes;

    // read pixel aspect ratio unit
    result = read1Byte(oneByte);
    if ((result == EOF) || (oneByte > 2))
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");
    unt = oneByte;

    // read horizontal aspect ratio (XDensity)
    result = read2Bytes(twoBytes);
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");
    pah = twoBytes;

    // read vertical aspect ratio (YDensity)
    result = read2Bytes(twoBytes);
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");
    pav = twoBytes;

    // prepare return values and return
    jfifVersion  = jv;
    pixelAspectH = pah;
    pixelAspectV = pav;
    unit         = unt;

    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Dumping some JFIF image parameters:");
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource:   JFIF version: " << jfifVersion);
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource:   Horizontal Pixel Aspect Ratio " << pixelAspectH);
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource:   Vertical Pixel Aspect Ratio: " << pixelAspectV);
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource:   Units: " << unit);

    return EC_Normal;
}

// expects valid JPEG stream (especially exactly one SOI and one EOI marker)
OFCondition I2DJpegSource::extractRawJPEGStream(char*& pixelData, Uint32& pixLength)
{
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Extracting JPEG data from JPEG file");
    OFCondition cond;
    int marker = 0;
    Uint16 length;

    /* Calculate length of total stream as found in the file
     * Therefore, look at byte positions from SOI and EOI marker and
     * and exclude all APPn markers and COM markers in calculation
     */

    offile_off_t bytePosSOI    = 0;
    offile_off_t bytePosEOI    = 0;
    offile_off_t totalSkipSize = 0;
    OFList<offile_off_t> appPosAndLengths;

    OFListIterator(JPEGFileMapEntry*) entry = m_jpegFileMap.begin();
    while (entry != m_jpegFileMap.end())
    {
        marker = (*entry)->marker;

        if (marker == E_JPGMARKER_SOI)
        {
            bytePosSOI = (*entry)->bytePos;
            // Subtract one byte for the preceding 0xFF of the SOI-Marker
            bytePosSOI -= 1;
        }
        else if (marker == E_JPGMARKER_EOI)
        {
            bytePosEOI = (*entry)->bytePos;
            // No need to subtract / add bytes
            break;
        }
        else if (!m_keepAPPn && (marker >= E_JPGMARKER_APP0 && marker <= E_JPGMARKER_APP15))
        {
            DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Skipping application segment APP" << (marker - E_JPGMARKER_APP0));
            jpegFile.fseek((*entry)->bytePos - jpegFile.ftell(), SEEK_CUR);
            int result = read2Bytes(length);
            if (result == EOF)
            {
                jpegFile.fclose();
                return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");
            }
            // remember pos and length of APP data so we don't need a second "scan" for that
            appPosAndLengths.push_back((*entry)->bytePos - 1); // -1 for FF of marker
            appPosAndLengths.push_back(length);
            // add length of marker value to total APP size
            totalSkipSize += length;
            // add the marker length itself to total APP size
            totalSkipSize += 2;
        }
        else if (!m_keepCOM && marker == E_JPGMARKER_COM)
        {
            DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Skipping segment COM");
            jpegFile.fseek((*entry)->bytePos - jpegFile.ftell(), SEEK_CUR);
            int result = read2Bytes(length);
            if (result == EOF)
            {
                jpegFile.fclose();
                return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");
            }
            // remember pos and length of COM data so we don't need a second "scan" for that
            appPosAndLengths.push_back((*entry)->bytePos - 1); // -1 for FF of marker
            appPosAndLengths.push_back(length);
            // add length of marker value to total APP size
            totalSkipSize += length;
            // add the marker length itself to total APP size
            totalSkipSize += 2;
        }
        // Advance to next segment
        entry++;
    }

    if ((entry == m_jpegFileMap.end()) || (bytePosSOI == 0) || (bytePosEOI == 0)) // at least end marker was not found
        return EC_IllegalCall;

    offile_off_t rawStreamSize = bytePosEOI - bytePosSOI - totalSkipSize;
    // Start position n and endpos. m results in a total amount of m-n+1 bytes
    rawStreamSize++;

    // Allocate buffer for raw JPEG data
    // Only up to 2^32-2 bytes can be stored in one pixel data fragment in DICOM
    if ((rawStreamSize < 0) ||
        ((rawStreamSize >> 32) > 0) ||
        (OFstatic_cast(Uint32, rawStreamSize) > (OFstatic_cast(Uint32, 4294967294UL))))
    {
        DCMDATA_LIBI2D_ERROR(
            "I2DJpegSource: Raw JPEG stream length longer than 2^32 bytes (or larger than size_t capacity), aborting");
        return EC_MemoryExhausted;
    }
    pixelData = new char[OFstatic_cast(size_t, rawStreamSize)];
    // keep track of current write position in memory buffer
    char* currBufferPos = pixelData;

    // Go to starting position (SOI marker) of JPEG stream data
    jpegFile.fseek(bytePosSOI - 1, SEEK_SET);

    /* Copy everything but leave out APP segments
     */
    OFBool finished               = OFFalse;
    offile_off_t endOfBlock       = 0;
    offile_off_t startOfNextBlock = 0;
    while (!finished)
    {
        // determine position of the next block to be read
        if (appPosAndLengths.size() != 0)
        {
            // we have some APP blocks left
            endOfBlock = appPosAndLengths.front() - 1;
            appPosAndLengths.pop_front();
            startOfNextBlock = endOfBlock + appPosAndLengths.front() + 2; // +2 for marker
            appPosAndLengths.pop_front();
        }
        else // we can read to the end
        {
            endOfBlock = bytePosEOI;
            finished   = OFTrue;
        }
        // read block
        offile_off_t blockSize = endOfBlock - jpegFile.ftell();
        if (blockSize < 0)
        {
            DCMDATA_LIBI2D_ERROR("Length field in JPEG data bigger than remaining file");
            cond = makeOFCondition(OFM_dcmdata, 18, OF_error, "Length field in JPEG data bigger than remaining file");
        }
        if (cond.good())
        {
            size_t result = jpegFile.fread(currBufferPos, 1, OFstatic_cast(size_t, blockSize));
            if (result != OFstatic_cast(size_t, blockSize))
                cond = EC_IllegalCall;
            else if (!finished)
            {
                jpegFile.fseek(startOfNextBlock, SEEK_SET);
                currBufferPos += blockSize;
            }
        }
    }
    // update result variable
    pixLength = OFstatic_cast(Uint32, rawStreamSize);
    if (cond.bad())
    {
        delete[] pixelData;
    }
    return cond;
}

OFCondition I2DJpegSource::createJPEGFileMap()
{
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Examining JPEG file and creating map of JPEG markers");
    // clear any old data
    clearMap();
    E_JPGMARKER marker;
    JPEGFileMapEntry* entry = NULL;
    OFBool lastWasSOSMarker = OFFalse;
    OFCondition cond;

    /* Expect SOI at start of file */
    E_JPGMARKER first = E_JPGMARKER();
    cond              = firstMarker(first);
    if (cond.bad())
        return cond;
    entry          = new JPEGFileMapEntry();
    entry->bytePos = jpegFile.ftell();
    entry->marker  = first;
    m_jpegFileMap.push_back(entry);

    if (first != E_JPGMARKER_SOI)
        return makeOFCondition(
            OFM_dcmdata, 18, OF_error, "I2DJpegSource: SOI marker not found at beginning of JPEG stream");

    /* Scan miscellaneous markers until we reach EOI */
    while (cond.good())
    {
        cond = nextMarker(lastWasSOSMarker, marker);
        if (cond.good())
        {
            entry          = new JPEGFileMapEntry();
            entry->bytePos = jpegFile.ftell();
            entry->marker  = marker;
            m_jpegFileMap.push_back(entry);
            if (marker == E_JPGMARKER_SOS)
            {
                // FIXME: reset this to OFFalse after the next marker?
                lastWasSOSMarker = OFTrue;
            }
            else if (marker == E_JPGMARKER_JPGN7)
            {
                lastWasSOSMarker = OFTrue;
                m_isJPEGLS = OFTrue;
            }
            else if (marker == E_JPGMARKER_EOI)
            {
                // End of file reached
                cond = EC_Normal;
                break;
            }
            if (!isRSTMarker(marker)) // RST marker does not have a length that could be used for skipping
                skipVariable();
        }
    } /* end loop */
    debugDumpJPEGFileMap();
    return cond;
}

OFBool I2DJpegSource::isRSTMarker(const E_JPGMARKER& marker)
{
    return ((marker >= E_JPGMARKER_RST0) && (marker <= E_JPGMARKER_RST7));
}

OFBool I2DJpegSource::isSOFMarker(const E_JPGMARKER& marker, const OFBool isJPEGLS)
{
    if(isJPEGLS)
      return marker == E_JPGMARKER_JPGN7; // SOF55
    return ((marker >= E_JPGMARKER_SOF0) && (marker <= E_JPGMARKER_SOF15) && (marker != E_JPGMARKER_DHT)
            && (marker != E_JPGMARKER_DAC));
}

OFString I2DJpegSource::jpegMarkerToString(const E_JPGMARKER& marker, const OFBool isJPEGLS)
{
    switch (marker)
    {
        case (E_JPGMARKER_SOF0):
            return "SOF0: Baseline DCT";
            break;
        case (E_JPGMARKER_SOF1):
            return "SOF1: Extended sequential DCT";
            break;
        case (E_JPGMARKER_SOF2):
            return "SOF2: Progressive DCT";
            break;
        case (E_JPGMARKER_SOF3):
            return "SOF3: Lossless (sequential)";
            break;
        case (E_JPGMARKER_SOF5):
            return "SOF5: Differential sequential DCT";
            break;
        case (E_JPGMARKER_SOF6):
            return "SOF6: Differential progressive DCT";
            break;
        case (E_JPGMARKER_SOF7):
            return "SOF7: Differential lossless (sequential)";
            break;
        case (E_JPGMARKER_JPG):
            return "JPG: JPEG extension";
            break;
        case (E_JPGMARKER_SOF9):
            return "SOF9: Extended sequential DCT";
            break;
        case (E_JPGMARKER_SOF10):
            return "SOF10: Progressive DCT";
            break;
        case (E_JPGMARKER_SOF11):
            return "SOF11: Lossless (sequential)";
            break;
        case (E_JPGMARKER_SOF13):
            return "SOF13: Differential sequential DCT";
            break;
        case (E_JPGMARKER_SOF14):
            return "SOF14: Differential progressive DCT";
            break;
        case (E_JPGMARKER_SOF15):
            return "SOF15: Differential lossless (sequential)";
            break;
        case (E_JPGMARKER_DHT):
            return "DHT: Huffman table(s)";
            break;
        case (E_JPGMARKER_DAC):
            return "DAC: Arithmetic coding conditioning(s)";
            break;
        case (E_JPGMARKER_SOI):
            return "SOI: Start of image";
            break;
        case (E_JPGMARKER_EOI):
            return "EOI: End of image";
            break;
        case (E_JPGMARKER_SOS):
            return "SOS: Start of scan";
            break;
        case (E_JPGMARKER_DQT):
            return "DQT: Quantization table(s)";
            break;
        case (E_JPGMARKER_DNL):
            return "DNL: Number of lines";
            break;
        case (E_JPGMARKER_DRI):
            return "DRI: Define restart interval";
            break;
        case (E_JPGMARKER_DHP):
            return "DHP: Hierarchical progression";
            break;
        case (E_JPGMARKER_EXP):
            return "EXP: Expand reference component(s)";
            break;
        case (E_JPGMARKER_COM):
            return "COM: Comment";
            break;
        case (E_JPGMARKER_TEM):
            return "TEM: For temporary private use in arithmetic coding";
            break;

        default:
            if ((marker >= E_JPGMARKER_RST0) && (marker <= E_JPGMARKER_RST7))
            {
                return "RSTn: Restart interval termination";
                break;
            }
            if ((marker >= E_JPGMARKER_APP0) && (marker <= E_JPGMARKER_APP15))
            {
                return "APPn: Application segment";
                break;
            }
            if ((marker >= E_JPGMARKER_JPGN0) && (marker <= E_JPGMARKER_JPGN13))
            {
                if(marker == E_JPGMARKER_JPGN7 && isJPEGLS)
                  return "SOF55: Start of Frame (JLS)";
                return "JPGn: JPEG extension";
                break;
            }
            if ((marker >= E_JPGMARKER_RES0) && (marker <= E_JPGMARKER_RESN))
            {
                return "RESn";
                break;
            }
    }
    OFString msg = "UNKNOWN MARKER :";
    char hexNo[10];
    sprintf(hexNo, "%x2", marker);
    msg += hexNo;
    return msg;
}

/* Read one byte, testing for EOF */
int I2DJpegSource::read1Byte(Uint8& result)
{
    int c;
    c = jpegFile.fgetc();
    if (c == EOF)
        return EOF;
    result = OFstatic_cast(Uint8, c);
    return 0;
}

/* Read 2 bytes, convert to unsigned int */
/* All 2-byte quantities in JPEG markers are MSB first */
int I2DJpegSource::read2Bytes(Uint16& result)
{
    int c1, c2;
    c1 = jpegFile.fgetc();
    if (c1 == EOF)
        return EOF;
    c2 = jpegFile.fgetc();
    if (c2 == EOF)
        return EOF;
    result = OFstatic_cast(Uint16, ((OFstatic_cast(Uint16, c1)) << 8) + OFstatic_cast(Uint16, c2));
    return 0;
}

/*
 * Find the next JPEG marker and return its marker code.
 * We expect at least one FF byte, possibly more if the compressor used FFs
 * to pad the file.
 * There could also be non-FF garbage between markers.  The treatment of such
 * garbage is unspecified; we choose to skip over it but emit a warning msg.
 */

OFCondition I2DJpegSource::nextMarker(const OFBool& lastWasSOSMarker, E_JPGMARKER& result)
{
    Uint8 c;
    int discarded_bytes = 0;
    int oneByte;
    OFBool isEscapeSequence; // used in the context of JPEG-LS
    const OFBool isJPEGLS = m_isJPEGLS; // local context

    do
    {
        /* Find 0xFF byte; count and skip any non-FFs. */
        oneByte = read1Byte(c);
        if (oneByte == EOF)
            return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");

        while (c != 0xFF)
        {
            if (!lastWasSOSMarker)
                discarded_bytes++;
            oneByte = read1Byte(c);
            if (oneByte == EOF)
                return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");
        }
        /* Get marker code byte, swallowing any duplicate FF bytes.  Extra FFs
         * are legal as pad bytes, so don't count them in discarded_bytes.
         */
        do
        {
            oneByte = read1Byte(c);
            if (oneByte == EOF)
                return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");
        } while (c == 0xFF);
        isEscapeSequence = c == 0x00;
        if( isJPEGLS )
          isEscapeSequence = c >= 0x00 && c <= 0x7f;
    } while (lastWasSOSMarker && isEscapeSequence);

    if (discarded_bytes != 0)
    {
        DCMDATA_LIBI2D_WARN("garbage data found in JPEG file");
    }
    result = OFstatic_cast(E_JPGMARKER, c);
    return EC_Normal;
}

/*
 * Read the initial marker, which should be SOI.
 * For a JFIF file, the first two bytes of the file should be literally
 * 0xFF M_SOI.
 */

OFCondition I2DJpegSource::firstMarker(E_JPGMARKER& result)
{
    Uint8 c1, c2;

    c1 = OFstatic_cast(Uint8, jpegFile.fgetc());
    c2 = OFstatic_cast(Uint8, jpegFile.fgetc());
    if (c1 != 0xFF || c2 != E_JPGMARKER_SOI)
    {
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Not a JPEG file");
    }
    result = OFstatic_cast(E_JPGMARKER, c2);
    return EC_Normal;
}

/*
 * Most types of marker are followed by a variable-length parameter segment.
 * This routine skips over the parameters for any marker we don't otherwise
 * want to process.
 * Note that we MUST skip the parameter segment explicitly in order not to
 * be fooled by 0xFF bytes that might appear within the parameter segment;
 * such bytes do NOT introduce new markers.
 */

OFCondition I2DJpegSource::skipVariable()
/* Skip over an unknown or uninteresting variable-length marker */
{
    Uint16 length;

    /* Get the marker parameter length count */
    int result = read2Bytes(length);
    if (result == EOF)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Premature EOF in JPEG file");
    /* Length includes itself, so must be at least 2 */
    if (length < 2)
        return makeOFCondition(OFM_dcmdata, 18, OF_error, "Erroneous JPEG marker length");
    length = OFstatic_cast(Uint16, length - 2);
    /* Skip over the remaining bytes */
    jpegFile.fseek(length, SEEK_CUR);
    return EC_Normal;
}

OFCondition I2DJpegSource::isJPEGEncodingSupported(const E_JPGMARKER& jpegEncoding) const
{
    OFCondition result;
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Checking whether JPEG encoding is supported");
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource:   Encoding: " << jpegMarkerToString(jpegEncoding, m_isJPEGLS));
    if(m_isJPEGLS)
    {
        switch (jpegEncoding)
        {
            case E_JPGMARKER_JPGN7: //
                result = EC_Normal;
                break;
            // SOF3: Lossless, SOF5-7: Hierarchical (differential), SOF9-15: Arithmetic coding, all other
            default:
                OFString errMsg("JPEG data with encoding: '");
                errMsg += jpegMarkerToString(jpegEncoding, m_isJPEGLS);
                errMsg += "' not supported";
                result = makeOFCondition(OFM_dcmdata, 18, OF_error, errMsg.c_str());
        }
    }
    else
    {
        switch (jpegEncoding)
        {
            case E_JPGMARKER_SOF0: // Baseline
                result = EC_Normal;
                break;
            case E_JPGMARKER_SOF1: // Extended sequential
                if (!m_disableExtSeqTs)
                    result = EC_Normal;
                else
                    result
                        = makeOFCondition(OFM_dcmdata,
                                        18,
                                        OF_error,
                                        "Unable to convert: Extended sequential JPEG coding found but support disabled");
                break;
            case E_JPGMARKER_SOF2: // Progressive
                if (!m_disableProgrTs)
                    result = EC_Normal;
                else
                    result = makeOFCondition(
                        OFM_dcmdata, 18, OF_error, "Unable to convert: Progressive JPEG coding found but disabled");
                break;
            // SOF3: Lossless, SOF5-7: Hierarchical (differential), SOF9-15: Arithmetic coding, all other
            default:
                OFString errMsg("JPEG data with encoding: '");
                errMsg += jpegMarkerToString(jpegEncoding, m_isJPEGLS);
                errMsg += "' not supported";
                result = makeOFCondition(OFM_dcmdata, 18, OF_error, errMsg.c_str());
        }
    }
    return result;
}

E_TransferSyntax I2DJpegSource::associatedTS(const E_JPGMARKER& jpegEncoding, OFBool const isJPEGLS, Uint8 const nearLossless)
{
    if(isJPEGLS)
    {
        switch (jpegEncoding)
        {
            case E_JPGMARKER_JPGN7: // SOF55
                return nearLossless == 0 ? EXS_JPEGLSLossless : EXS_JPEGLSLossy;
            default:
                return EXS_Unknown;
        }
    }
    else
    {
        switch (jpegEncoding)
        {
            case E_JPGMARKER_SOF0: // Baseline
                return EXS_JPEGProcess1;
            case E_JPGMARKER_SOF1: // Extended Sequential
                return EXS_JPEGProcess2_4;
            case E_JPGMARKER_SOF2: // Progressive
                return EXS_JPEGProcess10_12;
            default:
                return EXS_Unknown;
        }
    }
}

void I2DJpegSource::debugDumpJPEGFileMap() const
{
    if (!DCM_dcmdataLibi2dLogger.isEnabledFor(OFLogger::DEBUG_LOG_LEVEL))
        return;

    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Dumping JPEG marker file map:");
    if (m_keepAPPn)
        DCMDATA_LIBI2D_DEBUG(
            "I2DJpegSource: Keep APPn option enabled, any markers after SOFn marker will not be dumped");
    OFListConstIterator(JPEGFileMapEntry*) it = m_jpegFileMap.begin();
    while (it != m_jpegFileMap.end())
    {
        DCMDATA_LIBI2D_DEBUG("I2DJpegSource:   Byte Position: 0x"
                             << STD_NAMESPACE hex << STD_NAMESPACE setw(8)
                             << STD_NAMESPACE setfill('0')
                             /* need to cast bytePos to unsigned long to keep VC6 happy */
                             << OFstatic_cast(unsigned long, (*it)->bytePos)
                             << " | Marker: " << jpegMarkerToString((*it)->marker, m_isJPEGLS));
        it++;
    }
}

void I2DJpegSource::clearMap()
{
    // free memory of each map entry and remove them all from list
    JPEGFileMapEntry* entry = NULL;
    while (m_jpegFileMap.size() != 0)
    {
        entry = m_jpegFileMap.front();
        m_jpegFileMap.pop_front();
        delete entry;
        entry = NULL;
    }
}

// closes underlying JPEG file
void I2DJpegSource::closeFile()
{
    jpegFile.fclose();
}

// close file and free dynamically allocated memory
I2DJpegSource::~I2DJpegSource()
{
    DCMDATA_LIBI2D_DEBUG("I2DJpegSource: Closing JPEG file and cleaning up memory");
    closeFile();
    clearMap();
}
