text: //
  // SPDX-License-Identifier: BSD-3-Clause
  // Copyright (c) Contributors to the OpenEXR Project.
  //
  
  #ifdef NDEBUG
  #    undef NDEBUG
  #endif
  
  #include "compareB44.h"
  #include "compareDwa.h"
  
  #include <ImfRgbaFile.h>
  #include <ImfArray.h>
  #include <ImathRandom.h>
  #include <ImfThreading.h>
  #include <IlmThread.h>
  #include <IlmThreadSemaphore.h>
  #include <ImfThreading.h>
  
  #include <assert.h>
  #include <mutex>
  #include <stdio.h>
  #include <string>
  
  
  using namespace OPENEXR_IMF_NAMESPACE;
  using namespace std;
  using namespace IMATH_NAMESPACE;
  using namespace ILMTHREAD_NAMESPACE;
  
  
  #if ILMTHREAD_THREADING_ENABLED
  namespace {
  
  Rand48 rand1 (27);
  std::mutex scanlineMutex;
  Semaphore threadSemaphore;
  int remainingScanlines = 0;
  
  
  void
  fillPixels (Array2D<Rgba> &pixels, int w, int h)
  {
      assert (sizeof (int) == sizeof (float));
      
      for (int y = 0; y < h; ++y)
      {
  	for (int x = 0; x < w; ++x)
  	{
  	    Rgba &p = pixels[y][x];
  
  	    p.r = x % 100 + 100 * (y % 100) +
  		  rand1.nextf (-0.01f, -0.01f);
  
  	    p.g = 0.5 + 0.5 * sin (0.1 * x + 0.2 * y) +
                    rand1.nextf (-0.01f, -0.01f);
  
  	    p.b = 0.5 + 0.5 * sin (0.1 * x + 0.3 * y) +
                    rand1.nextf (-0.01f, -0.01f);
  
  	    p.a = rand1.nextf (0.0f, 1.0f);
  	}
      }
  }
  
  
  class WriterThread: public Thread
  {
    public:
  
      WriterThread (RgbaOutputFile *outfile);
  
      virtual void	run ();
  
    private:
  
      RgbaOutputFile *	_outfile;
  };
  
  
  WriterThread::WriterThread (RgbaOutputFile *outfile): _outfile (outfile)
  {
      start();
  }
  
  void
  WriterThread::run ()
  {
  
  
      while (true)
      {
  	std::lock_guard<std::mutex> lock (scanlineMutex);
  
  	if (remainingScanlines)
  	{
  	    int n = int (rand1.nextf (0.0f, remainingScanlines) + 0.5f);
  	    _outfile->writePixels (n);
  	    remainingScanlines -= n;
  	}
  	else
  	{
  	    break;
  	}
      }
  
      //
      // Signal that the thread has finished
      //
  
      threadSemaphore.post();
  }
      
  
  class ReaderThread : public Thread
  {
    public:
  
      ReaderThread (RgbaInputFile *infile, int start, int step);
  
      virtual void	run ();
  
    private:
  
      RgbaInputFile *	_infile;
      int			_start;
      int			_step;
  };
  
  
  ReaderThread::ReaderThread (RgbaInputFile *infile, int start, int step):
      _infile (infile), _start (start), _step (step)
  {
      Thread::start();
  }
  
  
  void
  ReaderThread::run ()
  {
  
  
      int num = _infile->header().dataWindow().max.y -
  	      _infile->header().dataWindow().min.y + 1;
  
      for (int i = _start; i < num; i += _step)
  	_infile->readPixels (i);
  
      //
      // Signal that the thread has finished
      //
  
      threadSemaphore.post ();
  
  }
      
  
  void
  writeReadRGBA (const char fileName[],
  	       int width,
  	       int height,
  	       const Array2D<Rgba> &p1,
  	       RgbaChannels channels,
  	       Compression comp)
  {
      //
      // Save the selected channels of RGBA image p1; save the
      // scan lines in the specified order.  Read the image back
      // from the file, and compare the data with the orignal.
      //
  
      cout << "channels " <<
  	    ((channels & WRITE_R)? "R": "") <<
  	    ((channels & WRITE_G)? "G": "") <<
  	    ((channels & WRITE_B)? "B": "") <<
  	    ((channels & WRITE_A)? "A": "") <<
  	    ", compression " << comp << ", " << flush;
  
      Header header (width, height);
      header.compression() = comp;
  
      {
  	remove (fileName);
          cout << "writing " << flush;
  	RgbaOutputFile out (fileName, header, channels);
          out.setFrameBuffer (&p1[0][0], 1, width);
          
          remainingScanlines = height;
          WriterThread writer1 (&out);
          WriterThread writer2 (&out);
          threadSemaphore.wait();
          threadSemaphore.wait();
      }
  
      {
          cout << "reading " << flush;
  	RgbaInputFile in (fileName);
  	const Box2i &dw = in.dataWindow();
  	
  	int w = dw.max.x - dw.min.x + 1;
  	int h = dw.max.y - dw.min.y + 1;
  	int dx = dw.min.x;
  	int dy = dw.min.y;
  
  	Array2D<Rgba> p2 (h, w);
  	in.setFrameBuffer (&p2[-dy][-dx], 1, w);
          
          {
              ReaderThread reader1 (&in, 0, 2);
              ReaderThread reader2 (&in, 1, 2);
              threadSemaphore.wait();
              threadSemaphore.wait();
          }
  
  	assert (in.displayWindow() == header.displayWindow());
  	assert (in.dataWindow() == header.dataWindow());
  	assert (in.pixelAspectRatio() == header.pixelAspectRatio());
  	assert (in.screenWindowCenter() == header.screenWindowCenter());
  	assert (in.screenWindowWidth() == header.screenWindowWidth());
  	assert (in.lineOrder() == header.lineOrder());
  	assert (in.compression() == header.compression());
  	assert (in.channels() == channels);
  
          cout << "comparing " << endl;
  
  	if (in.compression() == B44_COMPRESSION ||
  	    in.compression() == B44A_COMPRESSION)
  	{
  	    compareB44 (width, height, p1, p2, channels);
  	}
  	else if (in.compression() == DWAA_COMPRESSION ||
  	         in.compression() == DWAB_COMPRESSION)
  	{
  	    compareDwa (width, height, p1, p2, channels);
  	}
  	else
  	{
  	    for (int y = 0; y < h; ++y)
  	    {
  		for (int x = 0; x < w; ++x)
  		{
  		    if (channels & WRITE_R)
  			assert (p2[y][x].r == p1[y][x].r);
  		    else
  			assert (p2[y][x].r == 0);
  
  		    if (channels & WRITE_G)
  			assert (p2[y][x].g == p1[y][x].g);
  		    else
  			assert (p2[y][x].g == 0);
  
  		    if (channels & WRITE_B)
  			assert (p2[y][x].b == p1[y][x].b);
  		    else
  			assert (p2[y][x].b == 0);
  
  		    if (channels & WRITE_A)
  			assert (p2[y][x].a == p1[y][x].a);
  		    else
  			assert (p2[y][x].a == 1);
  		}
  	    }
  	}
      }
  
      remove (fileName);
  }
  
  
  } // namespace
  #endif
  
  void
  testSharedFrameBuffer (const std::string &tempDir)
  {
      try
      {
  	cout << "Testing reading from and writing to files using\n"
  		"multiple threads and a shared framebuffer" << endl;
  
          if (!ILMTHREAD_NAMESPACE::supportsThreads ())
          {
              cout << "   Threading not supported!" << endl << endl;
              return;
          }
                  
  #if ILMTHREAD_THREADING_ENABLED
  	const int W = 1371;
  	const int H = 159;
          
  	Array2D<Rgba> p1 (H, W);
  	fillPixels (p1, W, H);
          
          for (int n = 0; n <= 8; n++)
          {
              int numThreads = (n * 3) % 8;
  
              setGlobalThreadCount (numThreads);
              cout << "number of threads: " << globalThreadCount () << endl;
  
              for (int comp = 0; comp < NUM_COMPRESSION_METHODS; ++comp)
              {
                  writeReadRGBA ((tempDir + "imf_test_rgba.exr").c_str(),
                                  W, H, p1,
                                  WRITE_RGBA,
                                  Compression (comp));
  
                  writeReadRGBA ((tempDir + "imf_test_rgba.exr").c_str(),
                                  W, H, p1,
                                  WRITE_RGB,
                                  Compression (comp));
  
                  writeReadRGBA ((tempDir + "imf_test_rgba.exr").c_str(),
                                  W, H, p1,
                                  WRITE_A,
                                  Compression (comp));
  
                  writeReadRGBA ((tempDir + "imf_test_rgba.exr").c_str(),
                                  W, H, p1,
                                  RgbaChannels (WRITE_R | WRITE_B),
                                  Compression (comp));
              }
          }
  #endif
  	cout << "ok\n" << endl;
      }
      catch (const std::exception &e)
      {
  	cerr << "ERROR -- caught exception: " << e.what() << endl;
  	assert (false);
      }
  }
  