# lz4 : LZ4 compression in pure Go

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## Overview

This package provides a streaming interface to [LZ4 data streams](http://fastcompression.blogspot.fr/2013/04/lz4-streaming-format-final.html) as well as low level compress and uncompress functions for LZ4 data blocks.
The implementation is based on the reference C [one](https://github.com/lz4/lz4).

## Install

Assuming you have the go toolchain installed:

```
go get github.com/pierrec/lz4
```

There is a command line interface tool to compress and decompress LZ4 files.

```
go install github.com/pierrec/lz4/cmd/lz4c
```

Usage

```
Usage of lz4c:
  -version
        print the program version

Subcommands:
Compress the given files or from stdin to stdout.
compress [arguments] [<file name> ...]
  -bc
        enable block checksum
  -l int
        compression level (0=fastest)
  -sc
        disable stream checksum
  -size string
        block max size [64K,256K,1M,4M] (default "4M")

Uncompress the given files or from stdin to stdout.
uncompress [arguments] [<file name> ...]

```


## Example

```
// Compress and uncompress an input string.
s := "hello world"
r := strings.NewReader(s)

// The pipe will uncompress the data from the writer.
pr, pw := io.Pipe()
zw := lz4.NewWriter(pw)
zr := lz4.NewReader(pr)

go func() {
	// Compress the input string.
	_, _ = io.Copy(zw, r)
	_ = zw.Close() // Make sure the writer is closed
	_ = pw.Close() // Terminate the pipe
}()

_, _ = io.Copy(os.Stdout, zr)

// Output:
// hello world
```

## Contributing

Contributions are very welcome for bug fixing, performance improvements...!

- Open an issue with a proper description
- Send a pull request with appropriate test case(s)

## Contributors

Thanks to all contributors so far:

- [@klauspost](https://github.com/klauspost)
- [@heidawei](https://github.com/heidawei)
- [@x4m](https://github.com/x4m)
- [@Zariel](https://github.com/Zariel)
- [@edwingeng](https://github.com/edwingeng)
- [@danielmoy-google](https://github.com/danielmoy-google)
- [@honda-tatsuya](https://github.com/honda-tatsuya)
- [@h8liu](https://github.com/h8liu)
- [@sbinet](https://github.com/sbinet)
- [@fingon](https://github.com/fingon)
- [@emfree](https://github.com/emfree)
- [@lhemala](https://github.com/lhemala)
- [@connor4312](https://github.com/connor4312)
- [@oov](https://github.com/oov)
- [@arya](https://github.com/arya)
- [@ikkeps](https://github.com/ikkeps)

Special thanks to [@Zariel](https://github.com/Zariel) for his asm implementation of the decoder
Special thanks to [@klauspost](https://github.com/klauspost) for his work on optimizing the code