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ZstdNet

(★ 341)

Zstd wrapper for .NET

파일 탐색기

최종 버전 다운로드 (.zip)

- - build-and-test.yml
  - build-native.yml
  - pack-and-publish.yml
- - ZstdNet.targets
- - LICENSE
- CompressionOptions.cs
- CompressionStream.cs
- Compressor.cs
- Consts.cs
- DecompressionOptions.cs
- DecompressionStream.cs
- Decompressor.cs
- DictBuilder.cs
- ExternMethods.cs
- ThrowHelper.cs
- ZstdNet.csproj
- .gitignore
- CompressionBenchmarks.cs
- Main.cs
- ZstdNet.Benchmarks.csproj
- - AssemblyInfo.cs
- Binding_Tests.cs
- NativeResolver.cs
- SteamingCompressionTests.cs
- ZstdNet.Tests.csproj
.editorconfig
.gitignore
LICENSE
README.md
ZstdNet.slnx

# 설치 가이드

1. 코드 내려받기

git clone https://github.com/skbkontur/ZstdNet

깃허브에서 프로젝트 코드 전체를 내 컴퓨터로 내려받습니다.

cd ZstdNet

방금 내려받은 프로젝트 폴더 안으로 이동합니다.

2. .NET

보통 추천

사전 준비물

Git GitHub에서 프로젝트 코드를 내려받으려면 필요합니다.
.NET SDK dotnet 명령어를 쓰기 위한 SDK입니다.

cd ZstdNet.Benchmarks

이 프로젝트의 관련 파일이 하위 폴더 안에 있어서, 먼저 그 폴더로 이동합니다.

dotnet restore

프로젝트에 필요한 패키지를 내려받습니다.

dotnet run

프로젝트를 빌드하고 바로 실행합니다.

✅ dotnet run 실행 후 터미널에 나타나는 안내 메시지나 주소를 확인하세요.

// repository documentation

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# ZstdNet &ensp;[![License](https://img.shields.io/github/license/skbkontur/ZstdNet.svg)](https://raw.githubusercontent.com/skbkontur/ZstdNet/master/LICENSE)

[![Build and test](https://github.com/skbkontur/ZstdNet/actions/workflows/build-and-test.yml/badge.svg)](https://github.com/skbkontur/ZstdNet/actions/workflows/build-and-test.yml)
[![NuGet](https://img.shields.io/nuget/v/ZstdNet.svg)](https://www.nuget.org/packages/ZstdNet/)
[![NuGet Downloads](https://img.shields.io/nuget/dt/ZstdNet.svg)](https://www.nuget.org/packages/ZstdNet)
[![Reproducible Build](https://img.shields.io/badge/.NET%20Build-Reproducible-green)](https://nuget.info/packages/ZstdNet/1.5.7)
[![Provenance Attestation](https://img.shields.io/badge/Provenance-Attested-green)](https://github.com/skbkontur/ZstdNet/attestations)

**ZstdNet** is a wrapper of **Zstd** native library for .NET languages targeting `netstadard2.{0|1}`.
ZstdNet NuGet package includes pre-built native shared libraries for [various platforms](https://github.com/skbkontur/ZstdNet/blob/master/.github/workflows/build-native.yml), including `win`, `linux`, `osx`.
For `win`, the static VC runtime is used.

The package relies on the [dotnet runtime identifier resolution mechanism](https://learn.microsoft.com/en-us/dotnet/core/rid-catalog).
For .NET Framework, the package provides a [targets](https://github.com/skbkontur/ZstdNet/blob/master/ZstdNet/build/ZstdNet.targets) fallback, which requires an explicit selection of the platform — `x86`, `x64` or `ARM64`).

If you need to resolve native dependency at runtime, you can use the `NativeLibrary.SetDllImportResolver` (see an [example](https://github.com/skbkontur/ZstdNet/blob/master/ZstdNet.Tests/NativeResolver.cs)).
And for .NET Framework — `SetDllDirectory` from `kernel32.dll`.

Provenance attestation is enabled for all artifacts in this repository including native libs, see page [Attestations](https://github.com/skbkontur/ZstdNet/attestations).

### Features

* Compression and decompression of byte arrays and `Span<byte>`
* Streaming compression and decompression
* Advanced parameters support
* Generation of dictionaries

Take a look on a library reference or unit tests to explore its behavior in different situations.

## Zstd

**Zstandard**, or **zstd** as short version, is a fast lossless compression algorithm,
targeting real-time compression scenarios at zlib-level and better compression ratios.

**Zstd** is initially developed by Yann Collet and the source is available at:
https://github.com/facebook/zstd

The motivation to develop of the algorithm, ways of use and its properties are
explained in the blog that introduces the library:
http://fastcompression.blogspot.com/2015/01/zstd-stronger-compression-algorithm.html

The benefits of the dictionary mode are described here:
http://fastcompression.blogspot.ru/2016/02/compressing-small-data.html

## Reference

### Exceptions

The wrapper throws `ZstdException` in case of malformed data or an error inside *libzstd*.
If the given destination buffer is too small, `ZstdException` with `ZSTD_error_dstSize_tooSmall`
error code is thrown away.

Check [zstd_errors.h](https://github.com/facebook/zstd/blob/v1.5.7/lib/zstd_errors.h#L60) for more info.

### Compressor class

Block compression implementation. Instances of this class are **not thread-safe**.
Consider using `ThreadStatic` or pool of compressors for bulk processing.

* Constructor allow specifying compression options. Otherwise, default values will be used for `CompressionOptions`.

```c#
  Compressor();
  Compressor(CompressionOptions options);
  ```

Options will be exposed in `Options` read-only field.

Note that `Compressor` class implements `IDisposable`.
  If you use a lot of instances of this class,
  it's recommended to call `Dispose` to avoid loading on the finalizer thread. For example:

```c#
  using var compressor = new Compressor();
  var compressedData = compressor.Wrap(sourceData);
  ```

* `Wrap` compress data and save it in a new or an existing buffer (in such case a length of saved data will be returned).

```c#
  byte[] Wrap(byte[] src);
  byte[] Wrap(ArraySegment<byte> src);
  byte[] Wrap(ReadOnlySpan<byte> src);
  int Wrap(byte[] src, byte[] dst, int offset);
  int Wrap(ArraySegment<byte> src, byte[] dst, int offset);
  int Wrap(ReadOnlySpan<byte> src, byte[] dst, int offset);
  int Wrap(ReadOnlySpan<byte> src, Span<byte> dst);
  ```

Note that on buffers close to 2GB `Wrap` tries its best, but if `src` is uncompressible and its size is too large,
  `ZSTD_error_dstSize_tooSmall` will be thrown. `Wrap` method call will only be reliable for a buffer size such that
  `GetCompressBoundLong(size) <= 0x7FFFFFC7`. Consider using streaming compression API on large data inputs.

* `GetCompressBound` returns required destination buffer size for source data of size `size`.

```c#
  static int GetCompressBound(int size);
  static ulong GetCompressBoundLong(ulong size);
  ```

### CompressionStream class

Implementation of streaming compression. The stream is write-only.

* Constructor

```c#
  CompressionStream(Stream stream);
  CompressionStream(Stream stream, int bufferSize);
  CompressionStream(Stream stream, CompressionOptions options, int bufferSize = 0);
  ```

Options:
    - `Stream stream` &mdash; output stream for writing compressed data.
    - `CompressionOptions options`
      Default is `CompressionOptions.Default` with default compression level.
    - `int bufferSize` &mdash; buffer size used for compression buffer.
      Default is the result of calling `ZSTD_CStreamOutSize` which guarantees to successfully flush at least one complete compressed block (currently ~128KB).

The buffer for compression is allocated using `ArrayPool<byte>.Shared.Rent()`.

Note that `CompressionStream` class implements `IDisposable` and `IAsyncDisposable`.
  If you use a lot of instances of this class,
  it's recommended to call `Dispose` or `DisposeAsync` to avoid loading on the finalizer thread. For example:

```c#
  await using var compressionStream = new CompressionStream(outputStream, zstdBufferSize);
  await inputStream.CopyToAsync(compressionStream, copyBufferSize);
  ```

### CompressionOptions class

Stores compression options and "digested" (for compression) information
from a compression dictionary, if present.
Instances of this class **are thread-safe**. They can be shared across threads to avoid
performance and memory overhead.

* Constructor

```c#
  CompressionOptions(int compressionLevel);
  CompressionOptions(byte[] dict, int compressionLevel = DefaultCompressionLevel);
  CompressionOptions(byte[] dict, IReadOnlyDictionary<ZSTD_cParameter, int> advancedParams, int compressionLevel = DefaultCompressionLevel);
  ```

Options:
    - `byte[] dict` &mdash; compression dictionary.
      It can be read from a file or generated with `DictBuilder` class.
      Default is `null` (no dictionary).
    - `int compressionLevel` &mdash; compression level.
      Should be in range from `CompressionOptions.MinCompressionLevel` to `CompressionOptions.MaxCompressionLevel` (currently 22).
      Default is `CompressionOptions.DefaultCompressionLevel` (currently 3).
    - `IReadOnlyDictionary<ZSTD_cParameter, int> advancedParams` &mdash; advanced API provides a way
      to set specific parameters during compression. For example, it allows you to compress with multiple threads,
      enable long distance matching mode and more.
      Check [zstd.h](https://github.com/facebook/zstd/blob/v1.5.7/lib/zstd.h#L349) for additional info.

Specified options will be exposed in read-only fields.

Note that `CompressionOptions` class implements `IDisposable`.
  If you use a lot of instances of this class,
  it's recommended to call `Dispose` to avoid loading on the finalizer thread. For example:

```c#
  using var options = new CompressionOptions(dict, compressionLevel: 5);
  using var compressor = new Compressor(options);
  var compressedData = compressor.Wrap(sourceData);
  ```

### Decompressor class

Block decompression implementation. Instances of this class are **not thread-safe**.
Consider using `ThreadStatic` or pool of decompressors for bulk processing.

* Constructor allow specifying decompression options. Otherwise, default values for `DecompressionOptions` will be used.

```c#
  new Decompressor();
  new Decompressor(DecompressionOptions options);
  ```

Options will be exposed in `Options` read-only field.

Note that `Decompressor` class implements `IDisposable`.
  If you use a lot of instances of this class,
  it's recommended to call `Dispose` to avoid loading on the finalizer thread. For example:

```c#
  using var decompressor = new Decompressor();
  var decompressedData = decompressor.Unwrap(compressedData);
  ```

* `Unwrap` decompress data and save it in a new or an existing buffer (in such case a length of saved data will be returned).

```c#
  byte[] Unwrap(byte[] src, int maxDecompressedSize = int.MaxValue);
  byte[] Unwrap(ArraySegment<byte> src, int maxDecompressedSize = int.MaxValue);
  byte[] Unwrap(ReadOnlySpan<byte> src, int maxDecompressedSize = int.MaxValue);
  int Unwrap(byte[] src, byte[] dst, int offset, bool bufferSizePrecheck = true);
  int Unwrap(ArraySegment<byte> src, byte[] dst, int offset, bool bufferSizePrecheck = true);
  int Unwrap(ReadOnlySpan<byte> src, byte[] dst, int offset, bool bufferSizePrecheck = true);
  int Unwrap(ReadOnlySpan<byte> src, Span<byte> dst, bool bufferSizePrecheck = true);
  ```

Data can be saved to a new buffer only if a field with decompressed data size
  is present in compressed data. You can limit size of the new buffer with
  `maxDecompressedSize` parameter (it's necessary to do this on untrusted data).

If `bufferSizePrecheck` flag is set and the decompressed field length is specified,
  the size of the destination buffer will be checked before actual decompression.

Note that if this field is malformed (and is less than actual decompressed data size),
  *libzstd* still doesn't allow a buffer overflow to happen during decompression.

* `GetDecompressedSize` reads a field with decompressed data size stored in compressed data.

```c#
  static ulong GetDecompressedSize(byte[] src);
  static ulong GetDecompressedSize(ArraySegment<byte> src);
  static ulong GetDecompressedSize(ReadOnlySpan<byte> src);
  ```

### DecompressionStream class

Implementation of streaming decompression. The stream is read-only.

* Constructor

```c#
  DecompressionStream(Stream stream);
  DecompressionStream(Stream stream, int bufferSize);
  DecompressionStream(Stream stream, DecompressionOptions options, int bufferSize = 0);
  ```

Options:
    - `Stream stream` &mdash; input stream for reading raw data.
    - `DecompressionOptions options`
      Default is `null` (no dictionary).
    - `int bufferSize` &mdash; buffer size used for decompression buffer.
      Default is the result of calling `ZSTD_DStreamInSize` &mdash; recommended size for input buffer (currently ~128KB).

The buffer for decompression is allocated using `ArrayPool<byte>.Shared.Rent()`.

Note that `DecompressionStream` class implements `IDisposable` and `IAsyncDisposable`.
  If you use a lot of instances of this class,
  it's recommended to call `Dispose` or `DisposeAsync` to avoid loading on the finalizer thread. For example:

```c#
  await using var decompressionStream = new DecompressionStream(inputStream, zstdBufferSize);
  await decompressionStream.CopyToAsync(outputStream, copyBufferSize);
  ```

### DecompressionOptions class

Stores decompression options and "digested" (for decompression) information
from a compression dictionary, if present.
Instances of this class **are thread-safe**. They can be shared across threads to avoid
performance and memory overhead.

* Constructor

```c#
  DecompressionOptions();
  DecompressionOptions(byte[] dict);
  DecompressionOptions(byte[] dict, IReadOnlyDictionary<ZSTD_dParameter, int> advancedParams);
  ```

Options:
    - `byte[] dict` &mdash; compression dictionary.
      It can be read from a file or generated with `DictBuilder` class.
      Default is `null` (no dictionary).
    - `IReadOnlyDictionary<ZSTD_dParameter, int> advancedParams` &mdash; advanced decompression API
      that allows you to set parameters like maximum memory usage.
      Check [zstd.h](https://github.com/facebook/zstd/blob/v1.5.7/lib/zstd.h#L640) for additional info.

Specified options will be exposed in read-only fields.

Note that `CompressionOptions` class implements `IDisposable`.
  If you use a lot of instances of this class,
  it's recommended to call `Dispose` to avoid loading on the finalizer thread. For example:

```c#
  using var options = new DecompressionOptions(dict);
  using var decompressor = new Decompressor(options);
  var decompressedData = decompressor.Unwrap(compressedData);
  ```

### DictBuilder static class

* `TrainFromBuffer` generates a compression dictionary from a collection of samples.

```c#
  static byte[] TrainFromBuffer(IEnumerable<byte[]> samples, int dictCapacity = DefaultDictCapacity);
  ```

Options:
    - `int dictCapacity` &mdash; maximal dictionary size in bytes.
      Default is `DictBuilder.DefaultDictCapacity`, currently 110 KiB (the default in zstd utility).

## Wrapper Authors

Copyright (c) 2016-2026 [SKB Kontur](https://kontur.ru/eng/about)

*ZstdNet* is distributed under [BSD 3-Clause License](LICENSE).