基于PDC编码的中文文本压缩算法

Chinese text compression algorithm based on PDC coding

针对中文文本结构的特点以及传统压缩算法对中文文本压缩的不足,提出并实现了一个基于PDC编码的中文文本压缩算法。该算法采用的是字典压缩方式。根据单个汉字在中文文本出现的概率,采用Huffman编码方式进行前缀变长编码;定义由某个汉字为前缀的词组和短语的深度;对具有相同前缀和相同深度的词组和短语进行局部的定长编码,构成一部压缩编码字典。通过对相同文本分别使用该算法和传统的LZW和LZSS编码算法压缩后得到的数据结果对比,压缩率有2.53%~40.48%的提高,表明该压缩算法有较好的压缩效果。

According to the characteristics of Chinese text structures and the disadvantages of traditional compression algorithm for Chinese text compression, it proposes and implements a Chinese text compression algorithm based on PDC coding. The algorithm uses dictionary compression. According to the words＇ probability that appears in the Chinese text, the prefix encoded variable-length coding uses Huffman coding, it defines the depth of the phrases and short sentences that prefixed by the word, the algorithm encodes partial fixed-length coding for the phrases and short sentences which have the same prefix and depth, it constructs a compression dictionary. By comparing with the tradition compression algorithm LZW and LZSS that in the same texts, the compression algorithm＇s compression ratio increases 2.53% ~40.48%, which means the compression algorithm has a better compression effect than the traditional compression algorithm.