Method ReadLineRLE

IO/Image/vtkHDRReader.cxx:581–641

------------------------------------------------------------------------------

//------------------------------------------------------------------------------
bool vtkHDRReader::ReadLineRLE(vtkResourceStream* stream, unsigned char* lineBufferPtr)
{
  // A line in RLE is sorted by channels, ie. it begins by all the red, then green, blue, and
  // exponent It means that we need to read all the line even if we have an smaller extent
  int width = this->GetWidth();
  int count;
  // The data for each encoded channel
  unsigned char buffer[2];
  for (int i = 0; i < 4; ++i)
  {
    unsigned char* ptrEnd = lineBufferPtr + width;
    while (lineBufferPtr < ptrEnd)
    {
      std::size_t size = sizeof(unsigned char) * 2;
      if (stream->Read(buffer, size) != size)
      {
        vtkErrorMacro("Unable to read as expected");
        return false;
      }

      if (buffer[0] > 128)
      {
        // A run of the same value
        count = buffer[0] - 128;
        if ((count == 0) || (count > ptrEnd - lineBufferPtr))
        {
          return false;
        }

        // Copy the same value in the lineBuffer
        std::fill(lineBufferPtr, lineBufferPtr + count, buffer[1]);
        lineBufferPtr += count;
      }
      else
      {
        // A non run
        count = buffer[0];
        if ((count == 0) || (count > ptrEnd - lineBufferPtr))
        {
          return false;
        }

        *lineBufferPtr++ = buffer[1];
        // Read count bytes into output
        if (--count > 0)
        {

          size = sizeof(unsigned char) * count;
          if (stream->Read(lineBufferPtr, size) != size)
          {
            vtkErrorMacro("Unable to read as expected");
            return false;
          }
          lineBufferPtr += count;
        }
      }
    }
  }