Text Files Compression using Combination of two Dictionary methods (Specific dictionary for specific language and LZ77 Approach)

Abstract

In this paper we suggest combination between two dictionary methods. Specific dictionary (for specific language) and LZ77. The dictionary is used for replacing any word in it by its two Bytes index. A words not exists in the dictionary is written without changing preceded by four bits for length of this word. A modification was made on this approach for reducing the file to minimum size. Because of each wordwas replaced by two bytes (which are substituted in any appearance for this word in text), LZ77 can be used efficiently. Before this, the file is arranged specially in order to use LZ77 optimally for minimizing the data. This approach is tested on real text files and verifies it’s successful.