  Today there are many universal compression algorithms, but in most cases is
for specific data better using specific algorithm - JPEG for images, MPEG for
movies, etc. For textual documents there are special methods based on PPM
algorithm or methods with non-character access, e.g. word-based compression. In
the past, several papers describing variants of word-based compression using
Huffman encoding or LZW method were published. The subject of this paper is the
description of a word-based compression variant based on the LZ77 algorithm.
The LZ77 algorithm and its modifications are described in this paper. Moreover,
various ways of sliding window implementation and various possibilities of
output encoding are described, as well. This paper also includes the
implementation of an experimental application, testing of its efficiency and
finding the best combination of all parts of the LZ77 coder. This is done to
achieve the best compression ratio. In conclusion there is comparison of this
implemented application with other word-based compression programs and with
other commonly used compression programs.
