Partitionable Bus-based String-matching Algorithm for Run-length Coded Strings With VLDCs

Abstract

String matching (SM) problem is to find the occurrences of a pattern within a text. A vanable length don't care (VLDC) is a special symbol, not belonging to a finite alphabet ∑ but in ∑^*. Each VLDC in the pattern can match any substring in the text. Given a run-length coded text of length 2n over ∑ and a run-length coded pattern of length 2m over ∑^*, this paper first presents an O(1) time parallel SM algorithm for run-length coded strings with VLDCs on a reconfigurable mesh (RM) using O(nm) processors. Consider the hardware limitation in VLSI implementation. In order to be suitable for VLSI modular implementation, a partitionable parallel algorithm on the RM with limited processors is further presented. For N < n and M < m, the SM for run-length coded strings with VLDCs can be solved in O(X^Y^) time on the RM using O(NM)(= O((nm)/((X^Y^))) processors, where X^ = [(n – 1)/(N – 1)] and Y^ = [(m – 1)/(M – 1)].