https://github.com/zhztheplayer/DFA-Regex

A DFA regex engine in java.
https://github.com/zhztheplayer/DFA-Regex

dfa-regex java redos regex

Last synced: 7 days ago
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A DFA regex engine in java.

• Host: GitHub
• URL: https://github.com/zhztheplayer/DFA-Regex
• Owner: zhztheplayer
• License: other
• Created: 2015-05-14T02:13:18.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2024-08-03T07:47:15.000Z (3 months ago)
• Last Synced: 2024-08-03T16:49:34.928Z (3 months ago)
• Topics: dfa-regex, java, redos, regex
• Language: Java
• Homepage:
• Size: 52.7 KB
• Stars: 58
• Watchers: 2
• Forks: 17
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# DFA-Regex ![](https://travis-ci.org/zhztheplayer/DFA-Regex.svg?branch=master)

A DFA regex engine in java.

### Pom Settings

```xml

    top.yatt.dfargx

    dfargx

    0.2.1

```

### 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](https://en.wikipedia.org/wiki/ReDoS)

### Use Case

```java

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](https://en.wikipedia.org/wiki/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:

- [POSIX-Extended Regex](http://www.boost.org/doc/libs/1_44_0/libs/regex/doc/html/boost_regex/syntax/basic_extended.html) syntax support

- Liner time searching