String matching - Aho & Corasick

** Reference - Efficient String matching: An Aid to Bibliographic Search ** Alfred V Aho and Margaret J Corasick ** Bell Labratories ** Copyright(C) 1975 Association for Computing Machinery,Inc ** ** Implemented from the 4 algorithms in the paper by Aho & Corasick ** and some implementation ideas from 'Practical Algorithms in C' ** ** Notes: ** 1) This version uses about 1024 bytes per pattern character - heavy on the memory. ** 2) This algorithm finds all occurren ces of all patterns within a ** body of text. ** 3) Support is included to handle upper and lower case matching. ** 4) Some comopilers optimize the search routine well, others don't, this makes all the difference. ** 5) Aho inspects all bytes of the search text, but only once so it's very efficient, ** if the patterns are all large than the Modified Wu-Manbar method is often faster. ** 6) I don't subscribe to any one method is best for all searching needs, ** the data decides which method is best, ** and we don't know until after the search method has been tested on the specific data sets.