There is a new entropy coding approach: asymmetric numeral systems (ANS), which can be seen as simpler alternative for arithmetic coding: using a single natural number as the state, instead of two to represent the range. One of its variant is as computationally demanding as Huffman coding (large alphabet), but handles fractional amounts of bits - giving it accuracy (compression rate) like for arithmetic coding.
As there are reference implementations for Intel processor of data compression algorithms ( http://software.intel.com/sites/products/documentation/hpc/ipp/ipps/ipps_ch13/ch13_0_Intro.html ), maybe it would be worth to create them also for ANS?
Some implementation: https://github.com/Cyan4973/FiniteStateEntropy
With best regards,