Pattern Matching in Compressed Files

• Main Author: 邱登煌
• Other Authors: 李程輝
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/58701690450720875300

碩士 === 國立交通大學 === 電信工程系所 === 95 === Pattern matching is an important technique and it can be use to search specific contents in the files. We can apply pattern matching to virus detection and information retrieval. As data compression becomes more and more popular, the use of pattern matching in compressed files is avoidless, we must provide available approaches to improve the efficiency of search for this situation. This thesis presents the approaches for the applications of virus detection and information retrieval in compressed files to improve the efficiency. We propose the scheme of stream-based scanning in gzip compressed files, when packets arrive at Gateway continually, we can scan them immediately. Besides, we present the scheme of pattern matching for regular expression in LZW files with no decompression and it has better efficiency than decompress and then search in short patterns. We can apply the scheme to information retrieval system.