The TPIE stream header has a bit that indicates whether compression is used for the stream.

An uncompressed stream has blocks that begin on regular B-sized boundaries. A compressed stream has blocks of varying length that have a block header in the beginning and in the end of the block. The block header indicates what compression algorithm has been used for the block.

When opening a new stream for writing, the compressionFlags parameter sets whether compression should be enabled for the stream or not. If compression is enabled, blocks are compressed with the currently preferred compression scheme, which can be changed as follows:

tpie::compressor_thread_lock l(tpie::the_compressor_thread());

tpie::the_compressor_thread().set_preferred_compression(l, tpie::compression_scheme::snappy);

where snappy may be replaced with any scheme defined in tpie/compressed/scheme.h.