/DFA-Regex

A DFA regex engine in java.

Primary LanguageJavaOtherNOASSERTION

DFA-Regex

A DFA regex engine in java.

Pom Settings

<dependency>
    <groupId>top.yatt.dfargx</groupId>
    <artifactId>dfargx</artifactId>
    <version>0.2.1</version>
</dependency>

Introduction

This is a Java DFA regex engine implementation.

  • High compatibility -- single jar lib, without 3rd dependencies
  • High performance -- O(n) liner time complex, can be used for avoiding ReDoS

Use Case

RegexMatcher matcher = new RegexMatcher("\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}");
boolean result = matcher.match("192.168.0.255"); // return true or false, should be true in this case.

Performance Comparison With JDK Regex:

Below is showing a typical ReDoS attack input against a fragile regex pattern.

Regex Input Time Cost (Java Native) Time Cost (DFA Regex)
(a*)* aaaaaaaaaaaaaaaaab 42ms 12ms
(a*)* aaaaaaaaaaaaaaaaaaaaaaab 311ms 1ms
(a*)* aaaaaaaaaaaaaaaaaaaaaaaaaaaab 9579ms 1ms

Supported Features:

  • matching
  • searching
  • ascii character set
  • *, +, ?, {x}, {x,y}, {x}
  • ., \w, \W, \s, \S, \d, \D
  • complementary set [^a]
  • escape characters
  • brackets

Todo List: