A fast decoding algorithm for dictionary-based text compression system

A fast decoding algorithm is introduced her-e. This algorithm is proposed for the dictionary-based compression using fast hashing as searching engine[1]. Codes being encoded are divided into 2 classes, namely, copy and literal. 16 dictionaries are adopted and each of them contains a linked sub-dictionary if hashing values of two or more cones are collided. A hashing function developed by Pearson[2] is adopted here. It is used as a quick search to a specific word. However, it makes the speed of decode slower due to the hashing calculation. Therefore, before encoding a code, address re-ordering method is proposed. This method is used instead of hashing value as the address of the dictionary. Hence, there are three advantages provided Firstly, the address orders are concentrated. Secondly, there is no calculation of hashing is needed for decoding. Thirdly, lesser memory than that in the original is used for decoding. As a result, it can provide faster decode with lesser memory than that in the original and therefore, is more suitable to be used in the application, uwhich needs fast decoding non less memory such as 2-D bar cone.