Research and Implementation of File Format Identification Method Based on Pattern Matching

摘要

According to the characteristic of file format signature and the file recognition process, this paper improved BM algorithm and apply it to achieve file format identification. BM algorithm has higher efficiency in practical applications, but number of comparisons would be too much in application of file format identification, lead to reducing efficiency. We proposed to improve by adding two index tables. The improved algorithm mainly for the following cases in pattern matching: Find one pattern string in a text string;the number of the strings in pattern strings set more, and most pattern strings at the beginning of the text string. Compared with the BM algorithm, improved algorithm is more effective due to fewer comparisons between text string and strings of pattern strings set, and satisfied the requirement of file format identification.