# About Vectorscan

A fork of Intel's Hyperscan, modified to run on more platforms. Currently ARM NEON/ASIMD
is 100% functional, and Power VSX are in development. ARM SVE2 support is in ongoing with
access to hardware now. More platforms will follow in the future.

Vectorscan will follow Intel's API and internal algorithms where possible, but will not
hesitate to make code changes where it is thought of giving better performance or better
portability. In addition, the code will be gradually simplified and made more uniform and
all architecture specific -currently Intel- #ifdefs will be removed and abstracted away.

# Why was there a need for a fork?

Originally, the ARM porting was supposed to be merged into Intel's own Hyperscan, and 2 
Pull Requests had been made to the project for this reason ([1], [2]). Unfortunately, the
PRs were rejected for now and the forseeable future, thus we have created Vectorscan for 
our own multi-architectural and opensource collaborative needs.

# What is Hyperscan?

Hyperscan is a high-performance multiple regex matching library. It follows the
regular expression syntax of the commonly-used libpcre library, but is a
standalone library with its own C API.

Hyperscan uses hybrid automata techniques to allow simultaneous matching of
large numbers (up to tens of thousands) of regular expressions and for the
matching of regular expressions across streams of data.

Vectorscan is typically used in a DPI library stack, just like Hyperscan.

# Build Instructions

## Common Dependencies


## Native CPU detection

## Instructions for Intel/AMD CPUs

## Instructions for Arm 64-bit CPUs

## Instructions for Power8/Power9/Power10 CPUs


## Fat Runtime (Intel/AMD 64-bit & Arm 64-bit Only)



# Hyperscan Documentation

Information on building the Hyperscan library and using its API is available in
the [Developer Reference Guide](http://intel.github.io/hyperscan/dev-reference/).

# License

## Hyperscan License Change after 5.4

According to 
[Accelerate Snort Performance with Hyperscan and Intel Xeon Processors on Public Clouds](https://networkbuilders.intel.com/docs/networkbuilders/accelerate-snort-performance-with-hyperscan-and-intel-xeon-processors-on-public-clouds-1680176363.pdf) versions of Hyperscan later than 5.4 are
going to be closed-source:

> The latest open-source version (BSD-3 license) of Hyperscan on Github is 5.4. Intel conducts continuous internal
> development and delivers new Hyperscan releases under Intel Proprietary License (IPL) beginning from 5.5 for interested
> customers. Please contact authors to learn more about getting new Hyperscan releases.

Vectorscan continues to be an open source project and we are committed to keep it that way.
See the LICENSE file in the project repository.

# Versioning

The `master` branch on Github will always contain the most recent stable release of
Hyperscan. Each version released to `master` goes through QA and testing before
it is released; if you're a user, rather than a developer, this is the version
you should be using.

Further development towards the next release takes place on the `develop`
branch. All PRs are first made against the develop branch and if the pass the [Vectorscan CI](https://buildbot-ci.vectorcamp.gr/#/grid), then they get merged. Similarly with PRs from develop to master.

Vectorscan aims to be ABI and API compatible with the last open source version of Intel Hyperscan 5.4.
After careful consideration we decided that we will NOT aim to achieving compatibility with later Hyperscan versions 5.5/5.6 that have extended Hyperscan's API.
If keeping up to date with latest API of Hyperscan, you should talk to Intel and get a license to use that.
However, we intend to extend Vectorscan's API with user requested changes or API extensions and improvements that we think are best for the project.

# Get Involved

The official homepage for Vectorscan is at [www.github.com/VectorCamp/vectorscan](https://www.github.com/VectorCamp/vectorscan).

# Vectorscan Development

All development of Vectorscan is done in public. 

# Original Hyperscan links
For reference, the official homepage for Hyperscan is at [www.hyperscan.io](https://www.hyperscan.io).

And you can find the source code [on Github](https://github.com/intel/hyperscan).

For Intel Hyperscan related issues and questions, please follow the relevant links there.

[1]: https://github.com/intel/hyperscan/pull/272
[2]: https://github.com/intel/hyperscan/pull/287
