Johnathan, I'm getting a memory leak when using the gzip_decompressor due to a failure to call inflateEnd/deflateEnd during object destruction. I have inserted the following line into zlib.cpp tp correct the problem: void zlib_base::reset(bool compress) { z_stream* s = static_cast<z_stream*>(stream_); zlib_error::check(compress ? deflateReset(s) : inflateReset(s)); zlib_error::check(compress ? deflateEnd(s) : inflateEnd(s)); // gmg cleanup stream->state and embedded pointers } There may be a better place for this, for example in the zlib destructor, since it may be desirable on occasion to reset a stream without destroying the state (??). Or perhaps there should be a new function to encapsulate the call to deflateEnd/inflateEnd which is called in the destructor. Regards, George.