/*=========================================================================

  Program: GDCM (Grassroots DICOM). A DICOM library

  Copyright (c) 2006-2011 Mathieu Malaterre
  All rights reserved.
  See Copyright.txt or http://gdcm.sourceforge.net/Copyright.html for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
#include "gdcmTrace.h"
#include "gdcmTransferSyntax.h"

#include <limits.h>

/*
 * jdatasrc.c
 *
 * Copyright (C) 1994-1996, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains decompression data source routines for the case of
 * reading JPEG data from a file (or any stdio stream).  While these routines
 * are sufficient for most applications, some will want to use a different
 * source manager.
 * IMPORTANT: we assume that fread() will correctly transcribe an array of
 * JOCTETs from 8-bit-wide elements on external storage.  If char is wider
 * than 8 bits on your machine, you may need to do some tweaking.
 */

/* this is not a core library module, so it doesn't define JPEG_INTERNALS */

namespace gdcm
{

/* Expanded data source object for stdio input */

typedef struct {
  struct jpeg_source_mgr pub;  /* public fields */

  std::istream * infile;    /* source stream */
  JOCTET * buffer;    /* start of buffer */
  boolean start_of_file;  /* have we gotten any data yet? */
} my_source_mgr;

typedef my_source_mgr * my_src_ptr;

#define INPUT_BUF_SIZE  4096  /* choose an efficiently fread'able size */


/*
 * Initialize source --- called by jpeg_read_header
 * before any data is actually read.
 */

METHODDEF(void)
init_source (j_decompress_ptr cinfo)
{
  my_src_ptr src = (my_src_ptr) cinfo->src;

  /* We reset the empty-input-file flag for each image,
   * but we don't clear the input buffer.
   * This is correct behavior for reading a series of images from one source.
   */
  src->start_of_file = TRUE;
}


/*
 * Fill the input buffer --- called whenever buffer is emptied.
 *
 * In typical applications, this should read fresh data into the buffer
 * (ignoring the current state of next_input_byte & bytes_in_buffer),
 * reset the pointer & count to the start of the buffer, and return TRUE
 * indicating that the buffer has been reloaded.  It is not necessary to
 * fill the buffer entirely, only to obtain at least one more byte.
 *
 * There is no such thing as an EOF return.  If the end of the file has been
 * reached, the routine has a choice of ERREXIT() or inserting fake data into
 * the buffer.  In most cases, generating a warning message and inserting a
 * fake EOI marker is the best course of action --- this will allow the
 * decompressor to output however much of the image is there.  However,
 * the resulting error message is misleading if the real problem is an empty
 * input file, so we handle that case specially.
 *
 * In applications that need to be able to suspend compression due to input
 * not being available yet, a FALSE return indicates that no more data can be
 * obtained right now, but more may be forthcoming later.  In this situation,
 * the decompressor will return to its caller (with an indication of the
 * number of scanlines it has read, if any).  The application should resume
 * decompression after it has loaded more data into the input buffer.  Note
 * that there are substantial restrictions on the use of suspension --- see
 * the documentation.
 *
 * When suspending, the decompressor will back up to a convenient restart point
 * (typically the start of the current MCU). next_input_byte & bytes_in_buffer
 * indicate where the restart point will be if the current call returns FALSE.
 * Data beyond this point must be rescanned after resumption, so move it to
 * the front of the buffer rather than discarding it.
 */

METHODDEF(boolean)
fill_input_buffer (j_decompress_ptr cinfo)
{
  my_src_ptr src = (my_src_ptr) cinfo->src;
  size_t nbytes;

  //FIXME FIXME FIXME FIXME FIXME
  //nbytes = JFREAD(src->infile, src->buffer, INPUT_BUF_SIZE);
  std::streampos pos = src->infile->tellg();
  std::streampos end = src->infile->seekg(0, std::ios::end).tellg();
  src->infile->seekg(pos, std::ios::beg);
  //FIXME FIXME FIXME FIXME FIXME
  if( end == pos )
    {
    /* Start the I/O suspension simply by returning false here: */
    return FALSE;
    }
  if( (end - pos) < INPUT_BUF_SIZE )
    {
    src->infile->read( (char*)src->buffer, (size_t)(end - pos) );
    }
  else
    {
    src->infile->read( (char*)src->buffer, INPUT_BUF_SIZE);
    }

  std::streamsize gcount = src->infile->gcount();
  assert(gcount < INT_MAX);
  nbytes = (size_t)gcount;

  if (gcount <= 0) {
    if (src->start_of_file)  /* 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;
    nbytes = 2;
  }

  src->pub.next_input_byte = src->buffer;
  src->pub.bytes_in_buffer = nbytes;
  src->start_of_file = FALSE;

  return TRUE;
}


/*
 * Skip data --- used to skip over a potentially large amount of
 * uninteresting data (such as an APPn marker).
 *
 * Writers of suspendable-input applications must note that skip_input_data
 * is not granted the right to give a suspension return.  If the skip extends
 * beyond the data currently in the buffer, the buffer can be marked empty so
 * that the next read will cause a fill_input_buffer call that can suspend.
 * Arranging for additional bytes to be discarded before reloading the input
 * buffer is the application writer's problem.
 */

METHODDEF(void)
skip_input_data (j_decompress_ptr cinfo, long num_bytes)
{
  my_src_ptr src = (my_src_ptr) cinfo->src;

  /* 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->pub.bytes_in_buffer) {
      num_bytes -= (long) src->pub.bytes_in_buffer;
      (void) fill_input_buffer(cinfo);
      /* note we assume that fill_input_buffer will never return FALSE,
       * so suspension need not be handled.
       */
    }
    src->pub.next_input_byte += (size_t) num_bytes;
    src->pub.bytes_in_buffer -= (size_t) num_bytes;
  }
}


/*
 * An additional method that can be provided by data source modules is the
 * resync_to_restart method for error recovery in the presence of RST markers.
 * For the moment, this source module just uses the default resync method
 * provided by the JPEG library.  That method assumes that no backtracking
 * is possible.
 */


/*
 * Terminate source --- called by jpeg_finish_decompress
 * after all data has been read.  Often a no-op.
 *
 * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
 * application must deal with any cleanup that should happen even
 * for error exit.
 */

METHODDEF(void)
term_source (j_decompress_ptr cinfo)
{
  (void)cinfo;
  /* no work necessary here */
}


/*
 * Prepare for input from a stdio stream.
 * The caller must have already opened the stream, and is responsible
 * for closing it after finishing decompression.
 */

GLOBAL(void)
jpeg_stdio_src (j_decompress_ptr cinfo, std::istream & infile, bool flag)
{
  my_src_ptr src;

  /* The source object and input buffer are made permanent so that a series
   * of JPEG images can be read from the same file by calling jpeg_stdio_src
   * only before the first one.  (If we discarded the buffer at the end of
   * one image, we'd likely lose the start of the next one.)
   * This makes it unsafe to use this manager and a different source
   * manager serially with the same JPEG object.  Caveat programmer.
   */
  if (cinfo->src == nullptr) {  /* first time for this JPEG object? */
    cinfo->src = (struct jpeg_source_mgr *)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
          SIZEOF(my_source_mgr));
    src = (my_src_ptr) cinfo->src;
    src->buffer = (JOCTET *)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
          INPUT_BUF_SIZE * SIZEOF(JOCTET));
  }

  src = (my_src_ptr) cinfo->src;
  src->pub.init_source = init_source;
  src->pub.fill_input_buffer = fill_input_buffer;
  src->pub.skip_input_data = skip_input_data;
  src->pub.resync_to_restart = jpeg_resync_to_restart; /* use default method */
  src->pub.term_source = term_source;
  src->infile = &infile;
  if( flag )
    {
    src->pub.bytes_in_buffer = 0; /* forces fill_input_buffer on first read */
    src->pub.next_input_byte = nullptr; /* until buffer loaded */
    }
}

} // end namespace gdcm


namespace gdcm
{
/*
 * The following was copy/paste from example.c
 */

struct my_error_mgr {
   struct jpeg_error_mgr pub; /* "public" fields */
   jmp_buf setjmp_buffer;     /* for return to caller */
};
typedef struct my_error_mgr* my_error_ptr;

class JPEGInternals
{
public:
  JPEGInternals():cinfo(),cinfo_comp(),jerr(),StateSuspension(0),SampBuffer(nullptr) {}
  jpeg_decompress_struct cinfo;
  jpeg_compress_struct cinfo_comp;
  my_error_mgr jerr;
  int StateSuspension;
  void *SampBuffer;
};

JPEGBITSCodec::JPEGBITSCodec()
{
  Internals = new JPEGInternals;
  BitSample = BITS_IN_JSAMPLE;
}

JPEGBITSCodec::~JPEGBITSCodec()
{
  delete Internals;
}

/*
 * Here's the routine that will replace the standard error_exit method:
 */
extern "C" {
METHODDEF(void) my_error_exit (j_common_ptr cinfo) {
   /* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
   my_error_ptr myerr = (my_error_ptr) cinfo->err;

   /* Always display the message. */
   /* We could postpone this until after returning, if we chose. */
   (*cinfo->err->output_message) (cinfo);

   /* Return control to the setjmp point */
   longjmp(myerr->setjmp_buffer, 1);
}
}

bool JPEGBITSCodec::GetHeaderInfo(std::istream &is, TransferSyntax &ts)
{
  /* This struct contains the JPEG decompression parameters and pointers to
   * working space (which is allocated as needed by the JPEG library).
   */
  jpeg_decompress_struct &cinfo = Internals->cinfo;

  /* We use our private extension JPEG error handler.
   * Note that this struct must live as long as the main JPEG parameter
   * struct, to avoid dangling-pointer problems.
   */
  my_error_mgr &jerr = Internals->jerr;
  /* More stuff */
  //FILE * infile;    /* source file */
  //JSAMPARRAY buffer;    /* Output row buffer */
  //int row_stride;    /* physical row width in output buffer */

  if( Internals->StateSuspension == 0 )
    {
    // Step 1: allocate and initialize JPEG decompression object
    //
    // We set up the normal JPEG error routines, then override error_exit.
    cinfo.err = jpeg_std_error(&jerr.pub);
    jerr.pub.error_exit = my_error_exit;
    // Establish the setjmp return context for my_error_exit to use.
    if (setjmp(jerr.setjmp_buffer))
      {
      // If we get here, the JPEG code has signaled an error.
      // We need to clean up the JPEG object, close the input file, and return.
      // But first handle the case IJG does not like:
      if ( jerr.pub.msg_code == JERR_BAD_PRECISION /* 18 */ )
        {
        this->BitSample = jerr.pub.msg_parm.i[0];
        assert( this->BitSample == 1 || this->BitSample == 8 || this->BitSample == 12 || this->BitSample == 16 );
        assert( this->BitSample == cinfo.data_precision );
        }
      jpeg_destroy_decompress(&cinfo);
      // TODO: www.dcm4che.org/jira/secure/attachment/10185/ct-implicit-little.dcm
      // weird Icon Image from GE...
      return false;
      }
    }

  if( Internals->StateSuspension == 0 )
    {
    // Now we can initialize the JPEG decompression object.
    jpeg_create_decompress(&cinfo);

    // Step 2: specify data source (eg, a file)
    jpeg_stdio_src(&cinfo, is, true);
    }
  else
    {
    jpeg_stdio_src(&cinfo, is, false);
    }

  /* Step 3: read file parameters with jpeg_read_header() */

  if ( Internals->StateSuspension < 2 )
    {
    if( jpeg_read_header(&cinfo, TRUE) == JPEG_SUSPENDED )
      {
      Internals->StateSuspension = 2;
      }
    // First of all are we using the proper JPEG decoder (correct bit sample):
    if( jerr.pub.num_warnings )
      {
      if ( jerr.pub.msg_code == 128 )
        {
        this->BitSample = jerr.pub.msg_parm.i[0];
        jpeg_destroy_decompress(&cinfo);
        return false;
        }
      else
        {
        assert( 0 );
        }
      }
    this->Dimensions[1] = cinfo.image_height;  /* Number of rows in image */
    this->Dimensions[0] = cinfo.image_width;    /* Number of columns in image */

    int prep = this->PF.GetPixelRepresentation();
    //this->BitSample = cinfo.data_precision;
    int precision = cinfo.data_precision;
    // if lossy it should only be 8 or 12, but for lossless it can be [2-16]
    if( precision == 1 )
      {
      // lossless !
      this->PF = PixelFormat( PixelFormat::SINGLEBIT );
      }
    else if( precision <= 8 )
      {
      this->PF = PixelFormat( PixelFormat::UINT8 );
      }
    else if( precision <= 12 )
      {
      this->PF = PixelFormat( PixelFormat::UINT12 );
      }
    else if( precision <= 16 )
      {
      // lossless !
      this->PF = PixelFormat( PixelFormat::UINT16 );
      }
    else
      {
      assert( 0 );
      }
    this->PF.SetPixelRepresentation( (uint16_t)prep );
    this->PF.SetBitsStored( (uint16_t)precision );
    assert( (precision - 1) >= 0 );
    this->PF.SetHighBit( (uint16_t)(precision - 1) );

  this->PlanarConfiguration = 0;
    // Let's check the color space:
    //  JCS_UNKNOWN    -> 0
    //  JCS_GRAYSCALE,    /* monochrome */
    //  JCS_RGB,    /* red/green/blue */
    //  JCS_YCbCr,    /* Y/Cb/Cr (also known as YUV) */
    //  JCS_CMYK,   /* C/M/Y/K */
    //  JCS_YCCK    /* Y/Cb/Cr/K */

    if( cinfo.jpeg_color_space == JCS_UNKNOWN )
      {
      // I do not know if this possible, it looks like IJG always computes a default
      if( cinfo.num_components == 1 )
        {
        PI = PhotometricInterpretation::MONOCHROME2;
        this->PF.SetSamplesPerPixel( 1 );
        }
      else if( cinfo.num_components == 3 )
        {
        PI = PhotometricInterpretation::RGB;
        this->PF.SetSamplesPerPixel( 3 );
        }
      else
        {
        assert( 0 );
        }
      }
    else if( cinfo.jpeg_color_space == JCS_GRAYSCALE )
      {
      assert( cinfo.num_components == 1 );
      PI = PhotometricInterpretation::MONOCHROME2;
      this->PF.SetSamplesPerPixel( 1 );
      }
    else if( cinfo.jpeg_color_space == JCS_RGB )
      {
      assert( cinfo.num_components == 3 );
      PI = PhotometricInterpretation::RGB;
      this->PF.SetSamplesPerPixel( 3 );
      }
    else if( cinfo.jpeg_color_space == JCS_YCbCr )
      {
      assert( cinfo.num_components == 3 );
      PI = PhotometricInterpretation::YBR_FULL_422;
      if( cinfo.process == JPROC_LOSSLESS )
        PI = PhotometricInterpretation::RGB; // wotsit ?
      this->PF.SetSamplesPerPixel( 3 );
      this->PlanarConfiguration = 1;
      }
    else if( cinfo.jpeg_color_space == JCS_CMYK )
      {
      assert( cinfo.num_components == 4 );
      PI = PhotometricInterpretation::CMYK;
      this->PF.SetSamplesPerPixel( 4 );
      }
    else if( cinfo.jpeg_color_space == JCS_YCCK )
      {
      assert( cinfo.num_components == 4 );
      gdcmWarningMacro( "JCS_YCCK is not handled. Setting to CMYK for now." );
      PI = PhotometricInterpretation::CMYK; // non-sense...oh well
      this->PF.SetSamplesPerPixel( 4 );
      }
    else
      {
      assert( 0 ); //TODO
      }
    }
  if( cinfo.process == JPROC_LOSSLESS )
    {
    int predictor = cinfo.Ss;
    /* not very user friendly... */
    switch(predictor)
      {
    case 1:
      ts = TransferSyntax::JPEGLosslessProcess14_1;
      break;
    default:
      ts = TransferSyntax::JPEGLosslessProcess14;
      break;
      }
    }
  else if( cinfo.process == JPROC_SEQUENTIAL )
    {
    if( this->BitSample == 8 )
      ts = TransferSyntax::JPEGBaselineProcess1;
    else if( this->BitSample == 12 )
      ts = TransferSyntax::JPEGExtendedProcess2_4;
    }
  else if( cinfo.process == JPROC_PROGRESSIVE )
    {
    if( this->BitSample == 8 )
      {
      ts = TransferSyntax::JPEGFullProgressionProcess10_12;
      }
    else if( this->BitSample == 12 )
      {
      ts = TransferSyntax::JPEGFullProgressionProcess10_12;
      }
    else
      {
      assert(0); // TODO
      return false;
      }
    }
  else
    {
    assert(0); // TODO
    return false;
    }
  if( cinfo.process == JPROC_LOSSLESS )
    {
    LossyFlag = false;
    }
  else
    {
    LossyFlag = true;
    }

  // Pixel density stuff:
/*
UINT8 density_unit
UINT16 X_density
UINT16 Y_density
  The resolution information to be written into the JFIF marker;
  not used otherwise.  density_unit may be 0 for unknown,
  1 for dots/inch, or 2 for dots/cm.  The default values are 0,1,1
  indicating square pixels of unknown size.
*/

  if( cinfo.density_unit != 0
    || cinfo.X_density != 1
    || cinfo.Y_density != 1
  )
    {
    gdcmWarningMacro( "Pixel Density from JFIF Marker is not supported (for now)" );
    //return false;
    }


#if 0
    switch ( cinfo.jpeg_color_space )
      {
    case JCS_GRAYSCALE:
      if( GetPhotometricInterpretation() != PhotometricInterpretation::MONOCHROME1
        && GetPhotometricInterpretation() != PhotometricInterpretation::MONOCHROME2 )
        {
        gdcmWarningMacro( "Wrong PhotometricInterpretation. DICOM says: " <<
          GetPhotometricInterpretation() << " but JPEG says: "
          << cinfo.jpeg_color_space );
        //Internals->SetPhotometricInterpretation( PhotometricInterpretation::MONOCHROME2 );
        this->PI = PhotometricInterpretation::MONOCHROME2;
        }
      break;
    case JCS_RGB:
      assert( GetPhotometricInterpretation() == PhotometricInterpretation::RGB );
      break;
    case JCS_YCbCr:
      if( GetPhotometricInterpretation() != PhotometricInterpretation::YBR_FULL &&
          GetPhotometricInterpretation() != PhotometricInterpretation::YBR_FULL_422 )
        {
        // DermaColorLossLess.dcm (lossless)
        // LEADTOOLS_FLOWERS-24-RGB-JpegLossy.dcm (lossy)
        gdcmWarningMacro( "Wrong PhotometricInterpretation. DICOM says: " <<
          GetPhotometricInterpretation() << " but JPEG says: "
          << cinfo.jpeg_color_space );
        // Here it gets nasty since apparently when this occurs lossless means
        // we should not do any color conversion, but we *might* be breaking
        // correct DICOM file.
        // FIXME FIXME
        /* prevent the library from performing any color space conversion */
        if ( cinfo.process == JPROC_LOSSLESS )
          {
          cinfo.jpeg_color_space = JCS_UNKNOWN;
          cinfo.out_color_space = JCS_UNKNOWN;
          }
        }
      break;
    default:
      assert(0);
      return false;
      }
    //assert( cinfo.data_precision == BITS_IN_JSAMPLE );
    //assert( cinfo.data_precision == this->BitSample );

    /* Step 4: set parameters for decompression */
    /* no op */
    }

  /* Step 5: Start decompressor */

  if (Internals->StateSuspension < 3 )
    {
    if ( jpeg_start_decompress(&cinfo) == FALSE )
      {
      /* Suspension: jpeg_start_decompress */
      Internals->StateSuspension = 3;
      }

    /* We may need to do some setup of our own at this point before reading
     * the data.  After jpeg_start_decompress() we have the correct scaled
     * output image dimensions available, as well as the output colormap
     * if we asked for color quantization.
     * In this example, we need to make an output work buffer of the right size.
     */
    /* JSAMPLEs per row in output buffer */
    row_stride = cinfo.output_width * cinfo.output_components;
    row_stride *= sizeof(JSAMPLE);
    /* Make a one-row-high sample array that will go away when done with image */
    buffer = (*cinfo.mem->alloc_sarray)
      ((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);

    /* Save the buffer in case of suspension to be able to reuse it later: */
    Internals->SampBuffer = buffer;
    }
  else
    {
    /* JSAMPLEs per row in output buffer */
    row_stride = cinfo.output_width * cinfo.output_components;
    row_stride *= sizeof(JSAMPLE);

    /* Suspension: re-use the buffer: */
    buffer = (JSAMPARRAY)Internals->SampBuffer;
    }

  /* Step 6: while (scan lines remain to be read) */
  /*           jpeg_read_scanlines(...); */

  /* Here we use the library's state variable cinfo.output_scanline as the
   * loop counter, so that we don't have to keep track ourselves.
   */
  while (cinfo.output_scanline < cinfo.output_height) {
    /* jpeg_read_scanlines expects an array of pointers to scanlines.
     * Here the array is only one element long, but you could ask for
     * more than one scanline at a time if that's more convenient.
     */
    if( jpeg_read_scanlines(&cinfo, buffer, 1) == 0 )
      {
      /* Suspension in jpeg_read_scanlines */
      Internals->StateSuspension = 3;
      return true;
      }
    os.write((char*)buffer[0], row_stride);
  }

  /* Step 7: Finish decompression */

  if( jpeg_finish_decompress(&cinfo) == FALSE )
    {
    /* Suspension: jpeg_finish_decompress */
    Internals->StateSuspension = 4;
    }
#endif

  /* Step 8: Release JPEG decompression object */

  /* This is an important step since it will release a good deal of memory. */
  jpeg_destroy_decompress(&cinfo);

  /* After finish_decompress, we can close the input file.
   * Here we postpone it until after no more JPEG errors are possible,
   * so as to simplify the setjmp error logic above.  (Actually, I don't
   * think that jpeg_destroy can do an error exit, but why assume anything...)
   */
  //fclose(infile);

  /* At this point you may want to check to see whether any corrupt-data
   * warnings occurred (test whether jerr.pub.num_warnings is nonzero).
   */
  /* In any case make sure the we reset the internal state suspension */
  Internals->StateSuspension = 0;

  /* And we're done! */
  return true;

}

/*
 * Note: see dcmdjpeg +cn option to avoid the YBR => RGB loss
 */
bool JPEGBITSCodec::DecodeByStreams(std::istream &is, std::ostream &os)
{
  /* This struct contains the JPEG decompression parameters and pointers to
   * working space (which is allocated as needed by the JPEG library).
   */
  jpeg_decompress_struct &cinfo = Internals->cinfo;

  /* We use our private extension JPEG error handler.
   * Note that this struct must live as long as the main JPEG parameter
   * struct, to avoid dangling-pointer problems.
   */
  my_error_mgr &jerr = Internals->jerr;
  /* More stuff */
  //FILE * infile;    /* source file */
  JSAMPARRAY buffer;    /* Output row buffer */
  size_t row_stride;    /* physical row width in output buffer */

  if( Internals->StateSuspension == 0 )
    {
    // Step 1: allocate and initialize JPEG decompression object
    //
    // We set up the normal JPEG error routines, then override error_exit.
    cinfo.err = jpeg_std_error(&jerr.pub);
    jerr.pub.error_exit = my_error_exit;
    // Establish the setjmp return context for my_error_exit to use.
    if (setjmp(jerr.setjmp_buffer))
      {
      // If we get here, the JPEG code has signaled an error.
      // We need to clean up the JPEG object, close the input file, and return.
      // But first handle the case IJG does not like:
      if ( jerr.pub.msg_code == JERR_BAD_PRECISION /* 18 */ )
        {
        this->BitSample = jerr.pub.msg_parm.i[0];
        //assert( this->BitSample == 8 || this->BitSample == 12 || this->BitSample == 16 );
        }
      jpeg_destroy_decompress(&cinfo);
      // TODO: www.dcm4che.org/jira/secure/attachment/10185/ct-implicit-little.dcm
      // weird Icon Image from GE...
      return false;
      }
    }

  if( Internals->StateSuspension == 0 )
    {
    // Now we can initialize the JPEG decompression object.
    jpeg_create_decompress(&cinfo);

    // Step 2: specify data source (eg, a file)
    jpeg_stdio_src(&cinfo, is, true);
    }
  else
    {
    jpeg_stdio_src(&cinfo, is, false);
    }

  /* Step 3: read file parameters with jpeg_read_header() */

  if ( Internals->StateSuspension < 2 )
    {
    if( jpeg_read_header(&cinfo, TRUE) == JPEG_SUSPENDED )
      {
      Internals->StateSuspension = 2;
      }
    // First of all are we using the proper JPEG decoder (correct bit sample):
    if( jerr.pub.num_warnings )
      {
      // PHILIPS_Gyroscan-12-MONO2-Jpeg_Lossless.dcm
      if ( jerr.pub.msg_code == JWRN_MUST_DOWNSCALE )
        {
        // PHILIPS_Gyroscan-12-Jpeg_Extended_Process_2_4.dcm
        // PHILIPS_Gyroscan-12-MONO2-Jpeg_Lossless.dcm
        // MARCONI_MxTWin-12-MONO2-JpegLossless-ZeroLengthSQ.dcm
        // LJPEG_BuginGDCM12.dcm
        gdcmDebugMacro( "JWRN_MUST_DOWNSCALE" );
        this->BitSample = jerr.pub.msg_parm.i[0];
        assert( cinfo.data_precision == this->BitSample );
        jpeg_destroy_decompress(&cinfo);
        return false;
        }
      else
        {
        assert( 0 );
        }
      }
    // Let's check the color space:
    // JCS_UNKNOWN    -> 0
    // JCS_GRAYSCALE
    // JCS_RGB
    // JCS_YCbCr
    // JCS_CMYK
    // JCS_YCCK

    // Sanity checks:
    const unsigned int * dims = this->GetDimensions();
    if( cinfo.image_width != dims[0]
      || cinfo.image_height != dims[1] )
      {
      gdcmWarningMacro( "dimension mismatch. JPEG is " <<
        cinfo.image_width << "," << cinfo.image_height << " while DICOM " << dims[0] <<
        "," << dims[1]  ); 
      //this->Dimensions[0] = cinfo.image_width;
      //this->Dimensions[1] = cinfo.image_height;
      /*
       * Long story short, the real issue is that class such as ImageRegionReader expect to read the
       * image information without ever touching the JPEG codestream...
       */
      return false;
      }
    assert( cinfo.image_width == dims[0] );
    assert( cinfo.image_height == dims[1] );

    switch ( cinfo.jpeg_color_space )
      {
    case JCS_GRAYSCALE:
      if( GetPhotometricInterpretation() != PhotometricInterpretation::MONOCHROME1
        && GetPhotometricInterpretation() != PhotometricInterpretation::MONOCHROME2 )
        {
        gdcmWarningMacro( "Wrong PhotometricInterpretation. DICOM says: " <<
          GetPhotometricInterpretation() << " but JPEG says: "
          << (int)cinfo.jpeg_color_space );
        //Internals->SetPhotometricInterpretation( PhotometricInterpretation::MONOCHROME2 );
        this->PI = PhotometricInterpretation::MONOCHROME2;
        }
      break;
    case JCS_RGB:
      //assert( GetPhotometricInterpretation() == PhotometricInterpretation::RGB );
        if ( cinfo.process == JPROC_LOSSLESS )
          {
          cinfo.jpeg_color_space = JCS_UNKNOWN;
          cinfo.out_color_space = JCS_UNKNOWN;
          }
        if( GetPhotometricInterpretation() == PhotometricInterpretation::YBR_RCT
         || GetPhotometricInterpretation() == PhotometricInterpretation::YBR_ICT )
          this->PI = PhotometricInterpretation::RGB;
      break;
    case JCS_YCbCr:
      if( GetPhotometricInterpretation() != PhotometricInterpretation::YBR_FULL &&
          GetPhotometricInterpretation() != PhotometricInterpretation::YBR_PARTIAL_422 &&
          GetPhotometricInterpretation() != PhotometricInterpretation::YBR_FULL_422 )
        {
        // DermaColorLossLess.dcm (lossless)
        // LEADTOOLS_FLOWERS-24-RGB-JpegLossy.dcm (lossy)
        gdcmWarningMacro( "Wrong PhotometricInterpretation. DICOM says: " <<
          GetPhotometricInterpretation() << " but JPEG says: "
          << (int)cinfo.jpeg_color_space );
        // Here it gets nasty since apparently when this occurs lossless means
        // we should not do any color conversion, but we *might* be breaking
        // correct DICOM file.
        // FIXME FIXME
        /* prevent the library from performing any color space conversion */
        cinfo.jpeg_color_space = JCS_UNKNOWN;
        cinfo.out_color_space = JCS_UNKNOWN;
        }
      if ( cinfo.process == JPROC_LOSSLESS )
        {
        //cinfo.jpeg_color_space = JCS_UNKNOWN;
        //cinfo.out_color_space = JCS_UNKNOWN;
        }
      if( GetPhotometricInterpretation() == PhotometricInterpretation::YBR_FULL
      || GetPhotometricInterpretation() == PhotometricInterpretation::YBR_PARTIAL_422
      || GetPhotometricInterpretation() == PhotometricInterpretation::YBR_FULL_422 )
        {
        cinfo.jpeg_color_space = JCS_UNKNOWN;
        cinfo.out_color_space = JCS_UNKNOWN;
        //this->PlanarConfiguration = 1;
        }
      break;
    case JCS_CMYK:
      assert( GetPhotometricInterpretation() == PhotometricInterpretation::CMYK );
      if ( cinfo.process == JPROC_LOSSLESS )
        {
        cinfo.jpeg_color_space = JCS_UNKNOWN;
        cinfo.out_color_space = JCS_UNKNOWN;
        }
      break;
    case JCS_UNKNOWN:
      if ( cinfo.process == JPROC_LOSSLESS )
        {
        cinfo.jpeg_color_space = JCS_UNKNOWN;
        cinfo.out_color_space = JCS_UNKNOWN;
        }
      break;
    default:
      assert(0);
      return false;
      }
    //assert( cinfo.data_precision == BITS_IN_JSAMPLE );
    //assert( cinfo.data_precision == this->BitSample );

    /* Step 4: set parameters for decompression */
    /* no op */
    }

  /* Step 5: Start decompressor */

  if (Internals->StateSuspension < 3 )
    {
    if ( jpeg_start_decompress(&cinfo) == FALSE )
      {
      /* Suspension: jpeg_start_decompress */
      Internals->StateSuspension = 3;
      }

    /* We may need to do some setup of our own at this point before reading
     * the data.  After jpeg_start_decompress() we have the correct scaled
     * output image dimensions available, as well as the output colormap
     * if we asked for color quantization.
     * In this example, we need to make an output work buffer of the right size.
     */
    /* JSAMPLEs per row in output buffer */
    row_stride = cinfo.output_width * cinfo.output_components;
    row_stride *= sizeof(JSAMPLE);
    /* Make a one-row-high sample array that will go away when done with image */
    buffer = (*cinfo.mem->alloc_sarray)
      ((j_common_ptr) &cinfo, JPOOL_IMAGE, (JDIMENSION)row_stride, 1);

    /* Save the buffer in case of suspension to be able to reuse it later: */
    Internals->SampBuffer = buffer;
    }
  else
    {
    /* JSAMPLEs per row in output buffer */
    row_stride = cinfo.output_width * cinfo.output_components;
    row_stride *= sizeof(JSAMPLE);

    /* Suspension: re-use the buffer: */
    buffer = (JSAMPARRAY)Internals->SampBuffer;
    }

  /* Step 6: while (scan lines remain to be read) */
  /*           jpeg_read_scanlines(...); */

  /* Here we use the library's state variable cinfo.output_scanline as the
   * loop counter, so that we don't have to keep track ourselves.
   */
  while (cinfo.output_scanline < cinfo.output_height) {
    /* jpeg_read_scanlines expects an array of pointers to scanlines.
     * Here the array is only one element long, but you could ask for
     * more than one scanline at a time if that's more convenient.
     */
    if( jpeg_read_scanlines(&cinfo, buffer, 1) == 0 )
      {
      /* Suspension in jpeg_read_scanlines */
      Internals->StateSuspension = 3;
      return true;
      }
    os.write((char*)buffer[0], row_stride);
  }

  /* Step 7: Finish decompression */

  if( jpeg_finish_decompress(&cinfo) == FALSE )
    {
    /* Suspension: jpeg_finish_decompress */
    Internals->StateSuspension = 4;
    return true;
    }

  /* we are done decompressing the file, now is a good time to store the type
     of compression used: lossless or not */
  if( cinfo.process == JPROC_LOSSLESS )
    {
    LossyFlag = false;
    }
  else
    {
    LossyFlag = true;
    }

  /* Step 8: Release JPEG decompression object */

  /* This is an important step since it will release a good deal of memory. */
  jpeg_destroy_decompress(&cinfo);

  /* After finish_decompress, we can close the input file.
   * Here we postpone it until after no more JPEG errors are possible,
   * so as to simplify the setjmp error logic above.  (Actually, I don't
   * think that jpeg_destroy can do an error exit, but why assume anything...)
   */
  //fclose(infile);

  /* At this point you may want to check to see whether any corrupt-data
   * warnings occurred (test whether jerr.pub.num_warnings is nonzero).
   */
  /* gdcmData/D_CLUNIE_MR4_JPLY.dcm produces a single warning:
   *  Invalid SOS parameters for sequential JPEG
   * Be nice with this one:
   */
  if( jerr.pub.num_warnings > 1 )
    {
    gdcmErrorMacro( "Too many warning during decompression of JPEG stream: " << jerr.pub.num_warnings );
    return false;
    }
  /* In any case make sure the we reset the internal state suspension */
  Internals->StateSuspension = 0;

  /* And we're done! */
  return true;
}

/*
 * jdatadst.c
 *
 * Copyright (C) 1994-1996, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains compression data destination routines for the case of
 * emitting JPEG data to a file (or any stdio stream).  While these routines
 * are sufficient for most applications, some will want to use a different
 * destination manager.
 * IMPORTANT: we assume that fwrite() will correctly transcribe an array of
 * JOCTETs into 8-bit-wide elements on external storage.  If char is wider
 * than 8 bits on your machine, you may need to do some tweaking.
 */

/**
 * \brief very low level C 'structure', used to decode jpeg file
 * Should not appear in the Doxygen supplied documentation
 */
typedef struct {
  struct jpeg_destination_mgr pub; /* public fields */

  std::ostream * outfile;    /* target stream */
  JOCTET * buffer;    /* start of buffer */
} my_destination_mgr;

typedef my_destination_mgr * my_dest_ptr;

#define OUTPUT_BUF_SIZE  4096  /* choose an efficiently fwrite'able size */

/*
 * Initialize destination --- called by jpeg_start_compress
 * before any data is actually written.
 */

METHODDEF(void)
init_destination (j_compress_ptr cinfo)
{
  my_dest_ptr dest = (my_dest_ptr) cinfo->dest;

  /* Allocate the output buffer --- it will be released when done with image */
  dest->buffer = (JOCTET *)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
          OUTPUT_BUF_SIZE * SIZEOF(JOCTET));

  dest->pub.next_output_byte = dest->buffer;
  dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
}


/*
 * Empty the output buffer --- called whenever buffer fills up.
 *
 * In typical applications, this should write the entire output buffer
 * (ignoring the current state of next_output_byte & free_in_buffer),
 * reset the pointer & count to the start of the buffer, and return TRUE
 * indicating that the buffer has been dumped.
 *
 * In applications that need to be able to suspend compression due to output
 * overrun, a FALSE return indicates that the buffer cannot be emptied now.
 * In this situation, the compressor will return to its caller (possibly with
 * an indication that it has not accepted all the supplied scanlines).  The
 * application should resume compression after it has made more room in the
 * output buffer.  Note that there are substantial restrictions on the use of
 * suspension --- see the documentation.
 *
 * When suspending, the compressor will back up to a convenient restart point
 * (typically the start of the current MCU). next_output_byte & free_in_buffer
 * indicate where the restart point will be if the current call returns FALSE.
 * Data beyond this point will be regenerated after resumption, so do not
 * write it out when emptying the buffer externally.
 */

METHODDEF(boolean)
empty_output_buffer (j_compress_ptr cinfo)
{
  my_dest_ptr dest = (my_dest_ptr) cinfo->dest;

  //if (JFWRITE(dest->outfile, dest->buffer, OUTPUT_BUF_SIZE) !=
  //    (size_t) OUTPUT_BUF_SIZE)
  //  ERREXIT(cinfo, JERR_FILE_WRITE);
  size_t output_buf_size = OUTPUT_BUF_SIZE;
  if( !dest->outfile->write((char*)dest->buffer, output_buf_size) )
    {
    ERREXIT(cinfo, JERR_FILE_WRITE);
    }

  dest->pub.next_output_byte = dest->buffer;
  dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;

  return TRUE;
}


/*
 * Terminate destination --- called by jpeg_finish_compress
 * after all data has been written.  Usually needs to flush buffer.
 *
 * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
 * application must deal with any cleanup that should happen even
 * for error exit.
 */

METHODDEF(void)
term_destination (j_compress_ptr cinfo)
{
  my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
  size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;

  /* Write any data remaining in the buffer */
  if (datacount > 0) {
    //if (JFWRITE(dest->outfile, dest->buffer, datacount) != datacount)
    //  ERREXIT(cinfo, JERR_FILE_WRITE);
    if( !dest->outfile->write((char*)dest->buffer, datacount) )
      ERREXIT(cinfo, JERR_FILE_WRITE);
  }
  //fflush(dest->outfile);
  dest->outfile->flush();
  /* Make sure we wrote the output file OK */
  //if (ferror(dest->outfile))
  if (dest->outfile->fail())
    ERREXIT(cinfo, JERR_FILE_WRITE);
}


/*
 * Prepare for output to a stdio stream.
 * The caller must have already opened the stream, and is responsible
 * for closing it after finishing compression.
 */

GLOBAL(void)
jpeg_stdio_dest (j_compress_ptr cinfo, /*FILE * */ std::ostream * outfile)
{
  my_dest_ptr dest;

  /* The destination object is made permanent so that multiple JPEG images
   * can be written to the same file without re-executing jpeg_stdio_dest.
   * This makes it dangerous to use this manager and a different destination
   * manager serially with the same JPEG object, because their private object
   * sizes may be different.  Caveat programmer.
   */
  if (cinfo->dest == nullptr) {  /* first time for this JPEG object? */
    cinfo->dest = (struct jpeg_destination_mgr *)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
          SIZEOF(my_destination_mgr));
  }

  dest = (my_dest_ptr) cinfo->dest;
  dest->pub.init_destination = init_destination;
  dest->pub.empty_output_buffer = empty_output_buffer;
  dest->pub.term_destination = term_destination;
  dest->outfile = outfile;
}

/*
 * Sample routine for JPEG compression.  We assume that the target file name
 * and a compression quality factor are passed in.
 */

bool JPEGBITSCodec::InternalCode(const char* input, unsigned long len, std::ostream &os)
{
  int quality = 100; (void)len;
  (void)quality;
  JSAMPLE * image_buffer = (JSAMPLE*)(void*)const_cast<char*>(input);  /* Points to large array of R,G,B-order data */
  const unsigned int *dims = this->GetDimensions();
  int image_height = dims[1];  /* Number of rows in image */
  int image_width = dims[0];    /* Number of columns in image */

  /* This struct contains the JPEG compression parameters and pointers to
   * working space (which is allocated as needed by the JPEG library).
   * It is possible to have several such structures, representing multiple
   * compression/decompression processes, in existence at once.  We refer
   * to any one struct (and its associated working data) as a "JPEG object".
   */
  struct jpeg_compress_struct cinfo;
  /* This struct represents a JPEG error handler.  It is declared separately
   * because applications often want to supply a specialized error handler
   * (see the second half of this file for an example).  But here we just
   * take the easy way out and use the standard error handler, which will
   * print a message on stderr and call exit() if compression fails.
   * Note that this struct must live as long as the main JPEG parameter
   * struct, to avoid dangling-pointer problems.
   */
  struct my_error_mgr jerr;
  /* More stuff */
  //FILE * outfile;    /* target file */
  std::ostream * outfile = &os;
  JSAMPROW row_pointer[1];  /* pointer to JSAMPLE row[s] */
  size_t row_stride;    /* physical row width in image buffer */

  /* Step 1: allocate and initialize JPEG compression object */

  /* We have to set up the error handler first, in case the initialization
   * step fails.  (Unlikely, but it could happen if you are out of memory.)
   * This routine fills in the contents of struct jerr, and returns jerr's
   * address which we place into the link field in cinfo.
   */
  cinfo.err = jpeg_std_error(&jerr.pub);
  jerr.pub.error_exit = my_error_exit;
    // Establish the setjmp return context for my_error_exit to use.
    if (setjmp(jerr.setjmp_buffer))
      {
      jpeg_destroy_compress(&cinfo);
      return false;
      }

  /* Now we can initialize the JPEG compression object. */
  jpeg_create_compress(&cinfo);

  /* Step 2: specify data destination (eg, a file) */
  /* Note: steps 2 and 3 can be done in either order. */

  /* Here we use the library-supplied code to send compressed data to a
   * stdio stream.  You can also write your own code to do something else.
   * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
   * requires it in order to write binary files.
   */
  //if ((outfile = fopen(filename, "wb")) == NULL) {
  //  fprintf(stderr, "can't open %s\n", filename);
  //  exit(1);
  //}
  jpeg_stdio_dest(&cinfo, outfile);

  /* Step 3: set parameters for compression */

  /* First we supply a description of the input image.
   * Four fields of the cinfo struct must be filled in:
   */
  cinfo.image_width = image_width;   /* image width and height, in pixels */
  cinfo.image_height = image_height;

  switch( this->GetPhotometricInterpretation() )
    {
  case PhotometricInterpretation::MONOCHROME1:
  case PhotometricInterpretation::MONOCHROME2:
  case PhotometricInterpretation::PALETTE_COLOR:
    cinfo.input_components = 1;     /* # of color components per pixel */
    cinfo.in_color_space = JCS_GRAYSCALE; /* colorspace of input image */
    break;
  case PhotometricInterpretation::RGB:
  case PhotometricInterpretation::YBR_RCT:
  case PhotometricInterpretation::YBR_ICT:
    cinfo.input_components = 3;    /* # of color components per pixel */
    cinfo.in_color_space = JCS_RGB;   /* colorspace of input image */
    break;
  case PhotometricInterpretation::YBR_FULL:
  case PhotometricInterpretation::YBR_FULL_422:
  case PhotometricInterpretation::YBR_PARTIAL_420:
  case PhotometricInterpretation::YBR_PARTIAL_422:
    cinfo.input_components = 3;    /* # of color components per pixel */
    cinfo.in_color_space = JCS_YCbCr;   /* colorspace of input image */
    break;
  case PhotometricInterpretation::HSV:
  case PhotometricInterpretation::ARGB:
  case PhotometricInterpretation::CMYK:
    // TODO !
  case PhotometricInterpretation::UNKNOWN:
  case PhotometricInterpretation::PI_END: // To please compiler
    return false;
    }
  //if ( cinfo.process == JPROC_LOSSLESS )
  //  {
  //  cinfo.in_color_space = JCS_UNKNOWN;
  //  }
  //assert( cinfo.image_height * cinfo.image_width * cinfo.input_components * sizeof(JSAMPLE) == len );

  /* Now use the library's routine to set default compression parameters.
   * (You must set at least cinfo.in_color_space before calling this,
   * since the defaults depend on the source color space.)
   */
  jpeg_set_defaults(&cinfo);

  /*
   * predictor = 1
   * point_transform = 0
   * => lossless transformation.
   * Basically you need to have point_transform = 0, but you can pick whichever predictor [1...7] you want
   * TODO: is there a way to pick the right predictor (best compression/fastest ?)
   */
  if( !LossyFlag )
    {
    jpeg_simple_lossless (&cinfo, 1, 0);
    //jpeg_simple_lossless (&cinfo, 7, 0);
    }

  /* Now you can set any non-default parameters you wish to.
   * Here we just illustrate the use of quality (quantization table) scaling:
   */
  if( !LossyFlag )
    {
    assert( Quality == 100 );
    }
  jpeg_set_quality(&cinfo, Quality, TRUE /* limit to baseline-JPEG values */);

  /*
   * See write_file_header
   */
  cinfo.write_JFIF_header = 0;
  //cinfo.density_unit = 2;
  //cinfo.X_density = 2;
  //cinfo.Y_density = 5;

  /* Step 4: Start compressor */

  /* TRUE ensures that we will write a complete interchange-JPEG file.
   * Pass TRUE unless you are very sure of what you're doing.
   */
  jpeg_start_compress(&cinfo, TRUE);

  /* Step 5: while (scan lines remain to be written) */
  /*           jpeg_write_scanlines(...); */

  /* Here we use the library's state variable cinfo.next_scanline as the
   * loop counter, so that we don't have to keep track ourselves.
   * To keep things simple, we pass one scanline per call; you can pass
   * more if you wish, though.
   */
  row_stride = image_width * cinfo.input_components;  /* JSAMPLEs per row in image_buffer */

  if( this->GetPlanarConfiguration() == 0 )
    {
    while (cinfo.next_scanline < cinfo.image_height) {
      /* jpeg_write_scanlines expects an array of pointers to scanlines.
       * Here the array is only one element long, but you could pass
       * more than one scanline at a time if that's more convenient.
       */
      row_pointer[0] = & image_buffer[cinfo.next_scanline * row_stride];
      (void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
    }
    }
  else
    {
    /*
     * warning: Need to read C.7.6.3.1.3 Planar Configuration (see note about Planar Configuration dummy value)
     */
    JSAMPLE *tempbuffer = (JSAMPLE*)malloc( row_stride * sizeof(JSAMPLE) );
    row_pointer[0] = tempbuffer;
    int offset = image_height * image_width;
    while (cinfo.next_scanline < cinfo.image_height) {
      assert( row_stride % 3 == 0 );
      JSAMPLE* ptempbuffer = tempbuffer;
      JSAMPLE* red   = image_buffer + cinfo.next_scanline * row_stride / 3;
      JSAMPLE* green = image_buffer + cinfo.next_scanline * row_stride / 3 + offset;
      JSAMPLE* blue  = image_buffer + cinfo.next_scanline * row_stride / 3 + offset * 2;
      for(size_t i = 0; i < row_stride / 3; ++i )
        {
        *ptempbuffer++ = *red++;
        *ptempbuffer++ = *green++;
        *ptempbuffer++ = *blue++;
        }
      (void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
    }
    free(tempbuffer);
    }

  /* Step 6: Finish compression */

  jpeg_finish_compress(&cinfo);
  /* After finish_compress, we can close the output file. */
  //fclose(outfile);

  /* Step 7: release JPEG compression object */

  /* This is an important step since it will release a good deal of memory. */
  jpeg_destroy_compress(&cinfo);

  /* And we're done! */
  return true;
}

bool JPEGBITSCodec::EncodeBuffer(std::ostream &os, const char *data, size_t datalen)
{
  (void)datalen;
  JSAMPLE * image_buffer = (JSAMPLE*)(void*)const_cast<char*>(data);  /* Points to large array of R,G,B-order data */
  const unsigned int *dims = this->GetDimensions();
  int image_height = dims[1];  /* Number of rows in image */
  int image_width = dims[0];    /* Number of columns in image */

  /* This struct contains the JPEG compression parameters and pointers to
   * working space (which is allocated as needed by the JPEG library).
   * It is possible to have several such structures, representing multiple
   * compression/decompression processes, in existence at once.  We refer
   * to any one struct (and its associated working data) as a "JPEG object".
   */
  jpeg_compress_struct &cinfo = Internals->cinfo_comp;
  /* This struct represents a JPEG error handler.  It is declared separately
   * because applications often want to supply a specialized error handler
   * (see the second half of this file for an example).  But here we just
   * take the easy way out and use the standard error handler, which will
   * print a message on stderr and call exit() if compression fails.
   * Note that this struct must live as long as the main JPEG parameter
   * struct, to avoid dangling-pointer problems.
   */
  my_error_mgr &jerr = Internals->jerr;
  /* More stuff */
  //FILE * outfile;    /* target file */
  std::ostream *outfile = &os;
  JSAMPROW row_pointer[1];  /* pointer to JSAMPLE row[s] */
  size_t row_stride;    /* physical row width in image buffer */

  if( Internals->StateSuspension == 0 )
    {
    /* Step 1: allocate and initialize JPEG compression object */

    /* We have to set up the error handler first, in case the initialization
     * step fails.  (Unlikely, but it could happen if you are out of memory.)
     * This routine fills in the contents of struct jerr, and returns jerr's
     * address which we place into the link field in cinfo.
     */
    cinfo.err = jpeg_std_error(&jerr.pub);
    jerr.pub.error_exit = my_error_exit;
    // Establish the setjmp return context for my_error_exit to use.
    if (setjmp(jerr.setjmp_buffer))
      {
      jpeg_destroy_compress(&cinfo);
      return false;
      }

    /* Now we can initialize the JPEG compression object. */
    jpeg_create_compress(&cinfo);

    /* Step 2: specify data destination (eg, a file) */
    /* Note: steps 2 and 3 can be done in either order. */

    /* Here we use the library-supplied code to send compressed data to a
     * stdio stream.  You can also write your own code to do something else.
     * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
     * requires it in order to write binary files.
     */
    //if ((outfile = fopen(filename, "wb")) == NULL) {
    //  fprintf(stderr, "can't open %s\n", filename);
    //  exit(1);
    //}
    }
  if( Internals->StateSuspension == 0 )
    {
    jpeg_stdio_dest(&cinfo, outfile);
    }

  /* Step 3: set parameters for compression */

  /* First we supply a description of the input image.
   * Four fields of the cinfo struct must be filled in:
   */
  if( Internals->StateSuspension == 0 )
  {
  cinfo.image_width = image_width;   /* image width and height, in pixels */
  cinfo.image_height = image_height;
  }

  if( Internals->StateSuspension == 0 )
    {
    switch( this->GetPhotometricInterpretation() )
      {
    case PhotometricInterpretation::MONOCHROME1:
    case PhotometricInterpretation::MONOCHROME2:
    case PhotometricInterpretation::PALETTE_COLOR:
      cinfo.input_components = 1;     /* # of color components per pixel */
      cinfo.in_color_space = JCS_GRAYSCALE; /* colorspace of input image */
      break;
    case PhotometricInterpretation::RGB:
    case PhotometricInterpretation::YBR_RCT:
    case PhotometricInterpretation::YBR_ICT:
      cinfo.input_components = 3;    /* # of color components per pixel */
      cinfo.in_color_space = JCS_RGB;   /* colorspace of input image */
      break;
    case PhotometricInterpretation::YBR_FULL:
    case PhotometricInterpretation::YBR_FULL_422:
    case PhotometricInterpretation::YBR_PARTIAL_420:
    case PhotometricInterpretation::YBR_PARTIAL_422:
      cinfo.input_components = 3;    /* # of color components per pixel */
      cinfo.in_color_space = JCS_YCbCr;   /* colorspace of input image */
      break;
    case PhotometricInterpretation::HSV:
    case PhotometricInterpretation::ARGB:
    case PhotometricInterpretation::CMYK:
      // TODO !
    case PhotometricInterpretation::UNKNOWN:
    case PhotometricInterpretation::PI_END: // To please compiler
      return false;
      }
    }
  //if ( cinfo.process == JPROC_LOSSLESS )
  //  {
  //  cinfo.in_color_space = JCS_UNKNOWN;
  //  }
  //assert( cinfo.image_height * cinfo.image_width * cinfo.input_components * sizeof(JSAMPLE) == len );

  /* Now use the library's routine to set default compression parameters.
   * (You must set at least cinfo.in_color_space before calling this,
   * since the defaults depend on the source color space.)
   */
  if( Internals->StateSuspension == 0 )
    {
    jpeg_set_defaults(&cinfo);
    }

  /*
   * predictor = 1
   * point_transform = 0
   * => lossless transformation.
   * Basically you need to have point_transform = 0, but you can pick whichever predictor [1...7] you want
   * TODO: is there a way to pick the right predictor (best compression/fastest ?)
   */
  if( Internals->StateSuspension == 0 )
    {
    if( !LossyFlag )
      {
      jpeg_simple_lossless (&cinfo, 1, 0);
      //jpeg_simple_lossless (&cinfo, 7, 0);
      }
    }

  /* Now you can set any non-default parameters you wish to.
   * Here we just illustrate the use of quality (quantization table) scaling:
   */
  if( !LossyFlag )
    {
    assert( Quality == 100 );
    }
  if( Internals->StateSuspension == 0 )
    {
    jpeg_set_quality(&cinfo, Quality, TRUE /* limit to baseline-JPEG values */);
    }

  if( Internals->StateSuspension == 0 )
    {
    /*
     * See write_file_header
     */
    cinfo.write_JFIF_header = 0;
    }
  //cinfo.density_unit = 2;
  //cinfo.X_density = 2;
  //cinfo.Y_density = 5;

  /* Step 4: Start compressor */

  if( Internals->StateSuspension == 0 )
    {
    /* TRUE ensures that we will write a complete interchange-JPEG file.
     * Pass TRUE unless you are very sure of what you're doing.
     */
    jpeg_start_compress(&cinfo, TRUE);
    Internals->StateSuspension = 1;
    }

  /* Step 5: while (scan lines remain to be written) */
  /*           jpeg_write_scanlines(...); */

  /* Here we use the library's state variable cinfo.next_scanline as the
   * loop counter, so that we don't have to keep track ourselves.
   * To keep things simple, we pass one scanline per call; you can pass
   * more if you wish, though.
   */
  row_stride = image_width * cinfo.input_components;  /* JSAMPLEs per row in image_buffer */

  if ( Internals->StateSuspension == 1 )
    {
    assert( this->GetPlanarConfiguration() == 0 );
    assert( row_stride * sizeof(JSAMPLE) == datalen );
      {
      //while (cinfo.next_scanline < cinfo.image_height) {
      /* jpeg_write_scanlines expects an array of pointers to scanlines.
       * Here the array is only one element long, but you could pass
       * more than one scanline at a time if that's more convenient.
       */
      row_pointer[0] = & image_buffer[cinfo.next_scanline * row_stride * 0];
      const JDIMENSION nscanline = jpeg_write_scanlines(&cinfo, row_pointer, 1);
      assert( nscanline == 1 ); (void)nscanline;
      assert(cinfo.next_scanline <= cinfo.image_height);
      //}
      }
    if(cinfo.next_scanline == cinfo.image_height)
      {
      Internals->StateSuspension = 2;
      }
    }

  /* Step 6: Finish compression */

  if (Internals->StateSuspension == 2 )
    {
    jpeg_finish_compress(&cinfo);
    /* After finish_compress, we can close the output file. */
    //fclose(outfile);
    }

  /* Step 7: release JPEG compression object */

  if (Internals->StateSuspension == 2 )
    {
    /* This is an important step since it will release a good deal of memory. */
    jpeg_destroy_compress(&cinfo);

    Internals->StateSuspension = 0;
    }

  /* And we're done! */
  return true;
}

bool JPEGBITSCodec::IsStateSuspension() const
{
  return Internals->StateSuspension != 0;
}

} // end namespace gdcm
