Method openStream

src/IECore/StreamIndexedIO.cpp:1654–1746

}

void StreamIndexedIO::Index::openStream()
{
	if ( m_stream->openMode() & (IndexedIO::Append|IndexedIO::Read) )
	{
		StreamIndexedIO::StreamFile &f = *m_stream;

		m_hasChanged = false;

		f.seekg( 0, std::ios::end );
		uint64_t fileLen;
		uint64_t end = fileLen = f.tellg();
		f.seekg( end-1*sizeof(uint64_t), std::ios::beg );

		uint64_t magicNumber = 0;
		readLittleEndian( f, magicNumber );

		if ( magicNumber == g_versionedMagicNumber )
		{
			end -= 3*sizeof(uint64_t);
			f.seekg( end, std::ios::beg );
			readLittleEndian( f, m_offset );
			readLittleEndian( f, m_version );
		}
		else if (magicNumber == g_unversionedMagicNumber )
		{
			m_version = 0;
			end -= 2*sizeof(uint64_t);
			f.seekg( end, std::ios::beg );
			readLittleEndian( f, m_offset );
		}
		else
		{
			throw IOException("Not a StreamIndexedIO file");
		}

		if (m_version >= 6)
		{
			end -= 2 * sizeof(int);
			f.seekg( end, std::ios::beg );

			int compressorCode;
			readLittleEndian( f, compressorCode );
			readLittleEndian( f, m_compressionLevel );
			m_compressor = getCompressor( compressorCode );
		}

		f.seekg( m_offset, std::ios::beg );

		if (m_version >= 2 )
		{
			// construct a memory stream source from the decompressed index data
			io::filtering_istream indexInStream;

			if( m_version >= 7 )
			{
				// read the compressed Index
				uint64_t indexCompressedSize = end - m_offset;
				std::vector<char> compressedIndex( indexCompressedSize );