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# lz4 : LZ4 compression in pure Go
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[![Go Reference ](https://pkg.go.dev/badge/github.com/pierrec/lz4/v4.svg )](https://pkg.go.dev/github.com/pierrec/lz4/v4)
[![CI ](https://github.com/pierrec/lz4/workflows/ci/badge.svg )](https://github.com/pierrec/lz4/actions)
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[![Go Report Card ](https://goreportcard.com/badge/github.com/pierrec/lz4 )](https://goreportcard.com/report/github.com/pierrec/lz4)
[![GitHub tag (latest SemVer) ](https://img.shields.io/github/tag/pierrec/lz4.svg?style=social )](https://github.com/pierrec/lz4/tags)
## 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:
```
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go get github.com/pierrec/lz4/v4
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```
There is a command line interface tool to compress and decompress LZ4 files.
```
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go install github.com/pierrec/lz4/v4/cmd/lz4c
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```
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 ](https://github.com/pierrec/lz4/graphs/contributors ) so far!
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.