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src/Source/OpenEXR/IlmImf/ImfScanLineInputFile.cpp  view on Meta::CPAN

            
    /// we need to keep the list sorted in the order they'll be written to memory
    bool operator<(const sliceOptimizationData& other ) const
    {
        return base < other.base;
    }
};
    

} // namespace


struct ScanLineInputFile::Data: public Mutex
{
    Header		header;		    // the image header
    int			version;            // file's version
    FrameBuffer		frameBuffer;	    // framebuffer to write into
    LineOrder		lineOrder;          // order of the scanlines in file
    int			minX;		    // data window's min x coord
    int			maxX;		    // data window's max x coord
    int			minY;		    // data window's min y coord
    int			maxY;		    // data window's max x coord
    vector<Int64>	lineOffsets;	    // stores offsets in file for
					    // each line
    bool		fileIsComplete;	    // True if no scanlines are missing
    					    // in the file
    int			nextLineBufferMinY; // minimum y of the next linebuffer
    vector<size_t>	bytesPerLine;       // combined size of a line over all
                                            // channels
    vector<size_t>	offsetInLineBuffer; // offset for each scanline in its
                                            // linebuffer
    vector<InSliceInfo>	slices;             // info about channels in file
    
    vector<LineBuffer*> lineBuffers;        // each holds one line buffer
    int			linesInBuffer;      // number of scanlines each buffer
                                            // holds
    size_t		lineBufferSize;     // size of the line buffer
    int                 partNumber;         // part number

    bool                memoryMapped;       // if the stream is memory mapped
    OptimizationMode    optimizationMode;   // optimizibility of the input file
    vector<sliceOptimizationData>  optimizationData; ///< channel ordering for optimized reading
    
    Data (int numThreads);
    ~Data ();
    
    inline LineBuffer * getLineBuffer (int number); // hash function from line
    						    // buffer indices into our
						    // vector of line buffers
    
    
};


ScanLineInputFile::Data::Data (int numThreads):
        partNumber(-1),
        memoryMapped(false)
{
    //
    // We need at least one lineBuffer, but if threading is used,
    // to keep n threads busy we need 2*n lineBuffers
    //

    lineBuffers.resize (max (1, 2 * numThreads));
}


ScanLineInputFile::Data::~Data ()
{
    for (size_t i = 0; i < lineBuffers.size(); i++)
        delete lineBuffers[i];
}


inline LineBuffer *
ScanLineInputFile::Data::getLineBuffer (int lineBufferNumber)
{
    return lineBuffers[lineBufferNumber % lineBuffers.size()];
}


namespace {


void
reconstructLineOffsets (OPENEXR_IMF_INTERNAL_NAMESPACE::IStream &is,
			LineOrder lineOrder,
			vector<Int64> &lineOffsets)
{
    Int64 position = is.tellg();

    try
    {
	for (unsigned int i = 0; i < lineOffsets.size(); i++)
	{
	    Int64 lineOffset = is.tellg();

	    int y;
	    OPENEXR_IMF_INTERNAL_NAMESPACE::Xdr::read <OPENEXR_IMF_INTERNAL_NAMESPACE::StreamIO> (is, y);

	    int dataSize;
	    OPENEXR_IMF_INTERNAL_NAMESPACE::Xdr::read <OPENEXR_IMF_INTERNAL_NAMESPACE::StreamIO> (is, dataSize);

	    Xdr::skip <StreamIO> (is, dataSize);

	    if (lineOrder == INCREASING_Y)
		lineOffsets[i] = lineOffset;
	    else
		lineOffsets[lineOffsets.size() - i - 1] = lineOffset;
	}
    }
    catch (...)
    {
	//
	// Suppress all exceptions.  This functions is
	// called only to reconstruct the line offset
	// table for incomplete files, and exceptions
	// are likely.
	//
    }

    is.clear();
    is.seekg (position);
}


void
readLineOffsets (OPENEXR_IMF_INTERNAL_NAMESPACE::IStream &is,
		 LineOrder lineOrder,
		 vector<Int64> &lineOffsets,
		 bool &complete)
{
    for (unsigned int i = 0; i < lineOffsets.size(); i++)
    {
	OPENEXR_IMF_INTERNAL_NAMESPACE::Xdr::read <OPENEXR_IMF_INTERNAL_NAMESPACE::StreamIO> (is, lineOffsets[i]);
    }

    complete = true;

    for (unsigned int i = 0; i < lineOffsets.size(); i++)
    {
	if (lineOffsets[i] <= 0)
	{
	    //
	    // Invalid data in the line offset table mean that
	    // the file is probably incomplete (the table is
	    // the last thing written to the file).  Either
	    // some process is still busy writing the file,
	    // or writing the file was aborted.
	    //
	    // We should still be able to read the existing
	    // parts of the file.  In order to do this, we
	    // have to make a sequential scan over the scan
	    // line data to reconstruct the line offset table.
	    //

	    complete = false;
	    reconstructLineOffsets (is, lineOrder, lineOffsets);
	    break;
	}
    }
}


void
readPixelData (InputStreamMutex *streamData,
               ScanLineInputFile::Data *ifd,
	       int minY,
	       char *&buffer,
	       int &dataSize)
{
    //
    // Read a single line buffer from the input file.
    //
    // If the input file is not memory-mapped, we copy the pixel data into
    // into the array pointed to by buffer.  If the file is memory-mapped,
    // then we change where buffer points to instead of writing into the
    // array (hence buffer needs to be a reference to a char *).
    //

    int lineBufferNumber = (minY - ifd->minY) / ifd->linesInBuffer;

    Int64 lineOffset = ifd->lineOffsets[lineBufferNumber];

    if (lineOffset == 0)
	THROW (IEX_NAMESPACE::InputExc, "Scan line " << minY << " is missing.");

    //
    // Seek to the start of the scan line in the file,
    // if necessary.
    //

    if ( !isMultiPart(ifd->version) )
    {
        if (ifd->nextLineBufferMinY != minY)
            streamData->is->seekg (lineOffset);
    }
    else
    {
        //
        // In a multi-part file, the file pointer may have been moved by
        // other parts, so we have to ask tellg() where we are.
        //
        if (streamData->is->tellg() != ifd->lineOffsets[lineBufferNumber])
            streamData->is->seekg (lineOffset);
    }

    //