The Algorithm BSTW is a data compression

Data compression

In computer science and information theory, data compression, source coding or bit-rate reduction is the process of encoding information using fewer bits than the original representation would use....

 algorithm, named after its designers, Bentley, Sleator, Tarjan and Wei in 1986. BSTW is a dictionary-based algorithm that uses a move-to-front transform

Move-to-front transform

The move-to-front transform is an encoding of data designed to improve the performance of entropy encoding techniques of compression...

 to keep recently-seen dictionary entries at the front of the dictionary. Dictionary references are then encoded using any of a number of encoding methods, usually Elias delta coding

Elias delta coding

Elias delta code is a universal code encoding the positive integers developed by Peter Elias. To code a number:#Write it in binary.#Count the bits and write down that number of bits in binary ....

 or Elias gamma coding

Elias gamma coding

Elias gamma code is a universal code encoding positive integers developed by Peter Elias. It is used most commonly when coding integers whose upper-bound cannot be determined beforehand.-Encoding:To code a number:#Write it in binary....

.