A Faster Decoding Technique for Huffman Codes Using Adjacent Distance Array

Abstract

The evaluation of Huffman-based algorithm can be measured in two ways: one in terms of space and another is decoding speed. As memory requirement is going to be reasonable, the time effectiveness of Huffman decoding is more significant. So, this research concentrated on making the decoding speed faster for Huffman codes as well as maintaining the compression ratio for text data. For this, a new technique based on an adjacent distance array is introduced here. Adjacent distance array can save the distances for each adjacent symbol by calculating their ASCII values. Also, we have used a threshold value so that we can skip large codeword for all the adjacent symbols that would be produced by traversing whole Huffman tree. During the decoding process, the adjacent distance array is used to decode adjacent symbols by computing the distances instead of traversing the whole Huffman tree. We have described the encoding and decoding processes for the proposed technique. Besides, we have tested the proposed method on a few renowned corpuses and compared the performance with existing Huffman-based methods. Therefore, we have found that the proposed method performs more effectively in terms of compression--decompression time.