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A regular expression matching circuit based on a modular nondeterministic finite automaton with multicharacter transition,” SASIMI’10,
, 2010
"... Abstract. In this paper, we propose a regular expression matching circuit based on a decomposed automaton. To implement a regular expression matching circuit, first, we convert regular expressions into a nondeterministic finite automaton (NFA). Then, to reduce the number of states, we convert the ..."
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Abstract. In this paper, we propose a regular expression matching circuit based on a decomposed automaton. To implement a regular expression matching circuit, first, we convert regular expressions into a nondeterministic finite automaton (NFA). Then, to reduce the number of states, we convert the NFA into a modular nondeterministic finite automaton with unbounded string transition (MNFAU). Next, to realize it by a feasible amount of hardware, we decompose the MNFAU into the deterministic finite automaton (DFA) and the NFA. The DFA part is implemented by an offchip memory and a simple sequencer, while the NFA part is implemented by a cascade of logic cells. Also, in this paper, we show that the MNFAU based implementation has lower area complexity than the DFA and the NFA based ones.
A Regular Expression Matching Circuit: Decomposed Nondeterministic Realization With Prefix Sharing and MultiCharacter Transition
"... Abstract This paper shows a compact realization of regular expression matching circuits on FPGAs. First, the given regular expression is converted into a nondeterministic finite automaton (NFA) by the modified McNaughtonYamada method. Second, to reduce the number of the states in the NFA, prefixe ..."
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Abstract This paper shows a compact realization of regular expression matching circuits on FPGAs. First, the given regular expression is converted into a nondeterministic finite automaton (NFA) by the modified McNaughtonYamada method. Second, to reduce the number of the states in the NFA, prefixes for the NFA are shared. Also, the NFA is converted into the NFA with multicharacter transition (MNFAU: Modular nondeterministic finite automaton with unbounded string transition). Third, the MNFAU is decomposed into the transition string part and the state transition part. The transition string part is represented by the AhoCorasic deterministic finite automaton (ACDFA), and it is implemented by an offchip memory and a register. On the other hand, the state transition part is implemented by a cascade of logic cells (LCs) and the the interconnection on the FPGA. We implemented the regular expressions for SNORT (an open source intrusion detection system) on a Xilinx FPGA. Experimental results showed that, the embedded memory size per a character of the MNFAU is reduced to 0.2% of the pipelined DFA; 4.2% of the bitpartitioned DFA; 41.0% of the MNFAU(3); and 71.4% of the MNFAU without prefix sharing. Also, the number of LCs per a character of the MNFAU is reduced to 0.9% of the pipelined DFA; 15.6% of the NFA; and 80.0% of MNFAU without prefix sharing.