Compare the performance of LZ77, LZ78 and LZW with respect to parsing efficiency, dictionary generation, coding efficiency, and ease of implementation.© BrainMass Inc. brainmass.com December 19, 2018, 8:44 pm ad1c9bdddf
The LZ77 compression algorithm is the most used compression algorithm, on which program like PkZip has their foundation along with a few other algorithms.
This algorithm works on a dictionary basis, by searching the window for the longest match with the beginning of the look-ahead buffer, and outputs a pointer to that match. Since it is possible that not even a one-character match is found, the output cannot consist of merely pointers. This is solved by outputting the first character of the look-ahead buffer after a match was found. If no match was found, a NULL pointer and the character at the coding position will be output.
LZ78 is part of the family of LZ dictionary algorithms, which work by caching in on repetition of small lexical units and larger phrases in data files. LZ77 and LZ78 are both dictionary coders, unlike minimum redundancy coders or run length coders. LZ77 is the sliding window compression ...