Base64 encoding and decoding at almost the speed of a memory copy
If base64 decoding speed makes a difference in your application, you should be considering <i>why</i> you are transmitting data in base64, a neat hack from the 1970's, which is non-human-readable, wastes 30% of the network bandwidth, kills compression, wastes RAM, is typically hard to random-access, and is generally a bad idea all round.