SharpToken 2.0.3

dotnet add package SharpToken --version 2.0.3                
NuGet\Install-Package SharpToken -Version 2.0.3                
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="SharpToken" Version="2.0.3" />                
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add SharpToken --version 2.0.3                
#r "nuget: SharpToken, 2.0.3"                
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
// Install SharpToken as a Cake Addin
#addin nuget:?package=SharpToken&version=2.0.3

// Install SharpToken as a Cake Tool
#tool nuget:?package=SharpToken&version=2.0.3                

SharpToken

NuGet dotnet Last Commit GitHub Issues Used by Contributors License

SharpToken is a C# library that serves as a port of the Python tiktoken library. It provides functionality for encoding and decoding tokens using GPT-based encodings. This library is built for .NET 6, .NET 8 and .NET Standard 2.0, making it compatible with a wide range of frameworks.

[!Important] The functionality in SharpToken has been added to Microsoft.ML.Tokenizers. Microsoft.ML.Tokenizers is a tokenizer library being developed by the .NET team and going forward, the central place for tokenizer development in .NET. By using Microsoft.ML.Tokenizers, you should see improved performance over existing tokenizer library implementations, including SharpToken. A stable release of Microsoft.ML.Tokenizers is expected alongside the .NET 9.0 release (November 2024). Instructions for migration can be found at https://github.com/dotnet/machinelearning/blob/main/docs/code/microsoft-ml-tokenizers-migration-guide.md.

Installation

To install SharpToken, use the NuGet package manager:

Install-Package SharpToken

Or, if you prefer using the .NET CLI:

dotnet add package SharpToken

For more information, visit the NuGet package page.

Usage

To use SharpToken in your project, first import the library:

using SharpToken;

Next, create an instance of GptEncoding by specifying the desired encoding or model:

// Get encoding by encoding name
var encoding = GptEncoding.GetEncoding("cl100k_base");

// Get encoding by model name
var encoding = GptEncoding.GetEncodingForModel("gpt-4");

You can then use the Encode method to encode a string:

var encoded = encoding.Encode("Hello, world!"); // Output: [9906, 11, 1917, 0]

And use the Decode method to decode the encoded tokens:

var decoded = encoding.Decode(encoded); // Output: "Hello, world!"

SharpToken also provides a high performance count method. It is usefull to check prompt size before sending it to a LLM or to use it in a TextSplitter/Chunker for RAG.

var count = encoding.CountTokens("Hello, world!"); // Output: 4

Supported Models

SharpToken currently supports the following models:

  • r50k_base
  • p50k_base
  • p50k_edit
  • cl100k_base
  • o200k_base

You can use any of these models when creating an instance of GptEncoding:

var r50kBaseEncoding = GptEncoding.GetEncoding("r50k_base");
var p50kBaseEncoding = GptEncoding.GetEncoding("p50k_base");
var p50kEditEncoding = GptEncoding.GetEncoding("p50k_edit");
var cl100kBaseEncoding = GptEncoding.GetEncoding("cl100k_base");
var o200kBaseEncoding = GptEncoding.GetEncoding("o200k_base");

Model Prefix Matching

Apart from specifying direct model names, SharpToken also provides functionality to map model names based on specific prefixes. This allows users to retrieve an encoding based on a model's prefix.

Here are the current supported prefixes and their corresponding encodings:

Model Prefix Encoding
gpt-4o o200k_base
gpt-4- cl100k_base
gpt-3.5-turbo- cl100k_base
gpt-35-turbo cl100k_base

Examples of model names that fall under these prefixes include:

  • For the prefix gpt-4o: gpt-4o, gpt-4o-2024-05-13, etc.
  • For the prefix gpt-4-: gpt-4-0314, gpt-4-32k, etc.
  • For the prefix gpt-3.5-turbo-: gpt-3.5-turbo-0301, gpt-3.5-turbo-0401, etc.
  • For the Azure deployment name gpt-35-turbo.

To retrieve the encoding name based on a model name or its prefix, you can use the GetEncodingNameForModel method:

string encodingName = Model.GetEncodingNameForModel("gpt-4-0314");  // This will return "cl100k_base"

If the provided model name doesn't match any direct model names or prefixes, the method will return null.

Understanding Encoded Values

When you encode a string using the Encode method, the returned value is a list of integers that represent tokens in the specified encoding. These tokens are a compact way of representing the input text and can be processed more efficiently by various algorithms.

For example, encoding the text "Hello world!" using the cl100k_base encoding might produce the following list of integers:

var encoded = cl100kBaseEncoding.Encode("Hello world!"); // Output: [9906, 1917, 0]

You can then use the Decode method to convert these tokenized integer values back into the original text:

var decoded = cl100kBaseEncoding.Decode(encoded); // Output: "Hello world!"

With SharpToken, you can seamlessly switch between different encodings to find the one that best suits your needs. Just remember to use the same encoding for both the Encode and Decode methods to ensure accurate results.

Advanced usage

Custom Allowed Sets

SharpToken allows you to specify custom sets of allowed special tokens when encoding text. To do this, pass a HashSet<string> containing the allowed special tokens as a parameter to the Encode method:

const string encodingName = "cl100k_base";
const string inputText = "Some Text <|endofprompt|>";
var allowedSpecialTokens = new HashSet<string> { "<|endofprompt|>" };

var encoding = GptEncoding.GetEncoding(encodingName);
var encoded = encoding.Encode(inputText, allowedSpecialTokens);
var expectedEncoded = new List<int> { 8538, 2991, 220, 100276 };

Assert.Equal(expectedEncoded, encoded);

Custom Disallowed Sets

Similarly, you can specify custom sets of disallowed special tokens when encoding text. Pass a HashSet<string> containing the disallowed special tokens as a parameter to the Encode method:

const string encodingName = "cl100k_base";
const string inputText = "Some Text";

var encoding = GptEncoding.GetEncoding(encodingName);

void TestAction()
{
    encoding.Encode(inputText, disallowedSpecial: new HashSet<string> { "Some" });
}

Assert.Throws<ArgumentException>(TestAction);

In this example, an ArgumentException is thrown because the input text contains a disallowed special token

Testing and Validation

SharpToken includes a set of test cases in the TestPlans.txt file to ensure its compatibility with the Python tiktoken library. These test cases validate the functionality and behavior of SharpToken, providing a reliable reference for developers. Running the unit tests and verifying the test cases helps maintain consistency between the C# SharpToken library and the original Python implementation.

Performance Compared to TiktokenSharp and TokenizerLib

SharpToken is the fastest library with the lowest allocations!

<details> <summary>Benchmark Code</summary>

[SimpleJob(RuntimeMoniker.Net60)]
[SimpleJob(RuntimeMoniker.Net80)]
[SimpleJob(RuntimeMoniker.Net471)]
[RPlotExporter]
[MemoryDiagnoser]
public class CompareBenchmark
{
    private GptEncoding _sharpToken;
    private TikToken _tikToken;
    private ITokenizer _tokenizer;
    private Tokenizer _mlTokenizer;
    private string _kLongText;

    [GlobalSetup]
    public async Task Setup()
    {
        _sharpToken = GptEncoding.GetEncoding("cl100k_base");
        _tikToken = await TikToken.GetEncodingAsync("cl100k_base").ConfigureAwait(false);
        _tokenizer = await TokenizerBuilder.CreateByModelNameAsync("gpt-4").ConfigureAwait(false);
        _kLongText = "King Lear, one of Shakespeare's darkest and most savage plays, tells the story of the foolish and Job-like Lear, who divides his kingdom, as he does his affections, according to vanity and whim. Lear’s failure as a father engulfs himself and his world in turmoil and tragedy.";
    }

    [Benchmark]
    public int SharpToken()
    {
        var sum = 0;
        for (var i = 0; i < 10000; i++)
        {
            var encoded = _sharpToken.Encode(_kLongText);
            var decoded = _sharpToken.Decode(encoded);
            sum += decoded.Length;
        }

        return sum;
    }

    [Benchmark]
    public int TiktokenSharp()
    {
        var sum = 0;
        for (var i = 0; i < 10000; i++)
        {
            var encoded = _tikToken.Encode(_kLongText);
            var decoded = _tikToken.Decode(encoded);
            sum += decoded.Length;
        }

        return sum;
    }

    [Benchmark]
    public int TokenizerLib()
    {
        var sum = 0;
        for (var i = 0; i < 10000; i++)
        {
            var encoded = _tokenizer.Encode(_kLongText);
            var decoded = _tokenizer.Decode(encoded.ToArray());
            sum += decoded.Length;
        }

        return sum;
    }

    [Benchmark]
    public int MLTokenizers()
    {
        var sum = 0;
        for (var i = 0; i < 10000; i++)
        {
            var encoded = _mlTokenizer.EncodeToIds(_kLongText);
            var decoded = _mlTokenizer.Decode(encoded);
            sum += decoded.Length;
        }

        return sum;
    }
}

</details>

BenchmarkDotNet v0.13.9+228a464e8be6c580ad9408e98f18813f6407fb5a, Windows 11 (10.0.22631.3296)
11th Gen Intel Core i9-11950H 2.60GHz, 1 CPU, 16 logical and 8 physical cores
.NET SDK 9.0.100-preview.2.24157.14
  [Host]               : .NET 8.0.3 (8.0.324.11423), X64 RyuJIT AVX2
  .NET 6.0             : .NET 6.0.28 (6.0.2824.12007), X64 RyuJIT AVX2
  .NET 8.0             : .NET 8.0.3 (8.0.324.11423), X64 RyuJIT AVX2
  .NET Framework 4.7.1 : .NET Framework 4.8.1 (4.8.9181.0), X64 RyuJIT VectorSize=256
Method Job Runtime Mean Error StdDev Median Gen0 Gen1 Allocated
MLTokenizers .NET 8.0 .NET 8.0 60.55 ms 1.143 ms 1.123 ms 60.45 ms 1000.0000 - 13.12 MB
MLTokenizers .NET 6.0 .NET 6.0 95.75 ms 1.374 ms 1.147 ms 95.54 ms 10500.0000 - 126.19 MB
MLTokenizers .NET Framework 4.7.1 .NET Framework 4.7.1 291.77 ms 5.811 ms 11.195 ms 291.64 ms 21000.0000 - 127.33 MB
SharpToken .NET 8.0 .NET 8.0 87.78 ms 1.700 ms 1.590 ms 87.34 ms 1000.0000 - 22.13 MB
SharpToken .NET 6.0 .NET 6.0 128.84 ms 1.718 ms 1.607 ms 128.17 ms 16250.0000 500.0000 196.31 MB
SharpToken .NET Framework 4.7.1 .NET Framework 4.7.1 356.21 ms 6.843 ms 10.854 ms 355.09 ms 34000.0000 1000.0000 204.39 MB
TokenizerLib .NET 8.0 .NET 8.0 109.26 ms 2.082 ms 4.482 ms 107.90 ms 18200.0000 600.0000 217.82 MB
TokenizerLib .NET 6.0 .NET 6.0 126.16 ms 2.959 ms 8.630 ms 122.34 ms 18000.0000 500.0000 217.82 MB
TokenizerLib .NET Framework 4.7.1 .NET Framework 4.7.1 374.71 ms 7.374 ms 16.794 ms 370.12 ms 40000.0000 1000.0000 243.79 MB
TiktokenSharp .NET 8.0 .NET 8.0 177.34 ms 3.506 ms 8.797 ms 174.98 ms 28000.0000 1000.0000 338.98 MB
TiktokenSharp .NET 6.0 .NET 6.0 196.17 ms 3.912 ms 8.422 ms 195.52 ms 26000.0000 666.6667 313.26 MB
TiktokenSharp .NET Framework 4.7.1 .NET Framework 4.7.1 488.22 ms 9.696 ms 15.931 ms 487.17 ms 63000.0000 1000.0000 378.31 MB

Performance

SharpToken is extreamly performance optimized on net8.0. It uses modern multibyte CPU instructions and almost no heap allocations.

All core methods have been tested on a large and a small input text.

Inputs:

  • SmallText: 453 B (text/plain)
  • LargeText: 51 KB (text/html)

Methods:

  • Encode: text to tokens
  • Decode: tokens to text
  • CountTokens: high performance API to count tokens of text
BenchmarkDotNet v0.13.12, Windows 11 (10.0.22631.3296/23H2/2023Update/SunValley3)
AMD Ryzen 9 3900X, 1 CPU, 24 logical and 12 physical cores
.NET SDK 8.0.200
  [Host]               : .NET 8.0.2 (8.0.224.6711), X64 RyuJIT AVX2
  .NET 6.0             : .NET 6.0.16 (6.0.1623.17311), X64 RyuJIT AVX2
  .NET 8.0             : .NET 8.0.2 (8.0.224.6711), X64 RyuJIT AVX2
  .NET Framework 4.7.1 : .NET Framework 4.8.1 (4.8.9181.0), X64 RyuJIT VectorSize=256
Method Mean Error StdDev Ratio RatioSD Allocated Alloc Ratio
.NET 8.0
Encode_SmallText 22.649 us 0.4244 us 0.4359 us 0.28 0.01 696 B 0.02
Encode_LargeText 4,542.505 us 87.7988 us 104.5182 us 0.24 0.01 155547 B 0.03
Decode_SmallText 1.623 us 0.0324 us 0.0373 us 0.44 0.02 2320 B 0.98
Decode_LargeText 454.570 us 6.8980 us 6.4524 us 0.80 0.02 286979 B 1.00
CountTokens_SmallText 22.008 us 0.1165 us 0.0909 us 0.28 0.00 184 B 0.005
CountTokens_LargeText 4,231.353 us 14.5157 us 11.3329 us 0.23 0.00 195 B 0.000
.NET 6.0
Encode_SmallText 36.370 us 0.7178 us 1.0962 us 0.45 0.02 37344 B 0.91
Encode_LargeText 11,213.070 us 219.6291 us 269.7243 us 0.59 0.02 5062574 B 0.91
Decode_SmallText 2.588 us 0.0394 us 0.0350 us 0.70 0.02 2320 B 0.98
Decode_LargeText 489.467 us 8.9195 us 8.3433 us 0.86 0.02 286985 B 1.00
CountTokens_SmallText 34.758 us 0.2027 us 0.1896 us 0.45 0.01 36832 B 0.907
CountTokens_LargeText 11,252.083 us 215.8912 us 212.0340 us 0.61 0.01 4907169 B 0.907
.NET Framework 4.7.1
Encode_SmallText 79.947 us 1.5621 us 3.0097 us 1.00 0.00 41138 B 1.00
Encode_LargeText 18,961.252 us 253.1816 us 236.8262 us 1.00 0.00 5567685 B 1.00
Decode_SmallText 3.723 us 0.0728 us 0.0997 us 1.00 0.00 2375 B 1.00
Decode_LargeText 570.787 us 11.0356 us 11.8080 us 1.00 0.00 287496 B 1.00
CountTokens_SmallText 77.521 us 1.0802 us 0.9020 us 1.00 0.00 40616 B 1.000
CountTokens_LargeText 18,485.392 us 313.5834 us 277.9836 us 1.00 0.00 5413237 B 1.000

Contributions and Feedback

If you encounter any issues or have suggestions for improvements, please feel free to open an issue or submit a pull request on the project's repository.

Hope you find SharpToken useful for your projects and welcome any feedback you may have.

Product Compatible and additional computed target framework versions.
.NET net5.0 was computed.  net5.0-windows was computed.  net6.0 is compatible.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 was computed.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 is compatible.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed. 
.NET Core netcoreapp2.0 was computed.  netcoreapp2.1 was computed.  netcoreapp2.2 was computed.  netcoreapp3.0 was computed.  netcoreapp3.1 was computed. 
.NET Standard netstandard2.0 is compatible.  netstandard2.1 was computed. 
.NET Framework net461 was computed.  net462 was computed.  net463 was computed.  net47 was computed.  net471 was computed.  net472 was computed.  net48 was computed.  net481 was computed. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen40 was computed.  tizen60 was computed. 
Xamarin.iOS xamarinios was computed. 
Xamarin.Mac xamarinmac was computed. 
Xamarin.TVOS xamarintvos was computed. 
Xamarin.WatchOS xamarinwatchos was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.
  • .NETStandard 2.0

    • No dependencies.
  • net6.0

    • No dependencies.
  • net8.0

    • No dependencies.

NuGet packages (17)

Showing the top 5 NuGet packages that depend on SharpToken:

Package Downloads
EachShow.AI

OpenAI, ChatGPT

Encamina.Enmarcha.SemanticKernel.Abstractions

Package Description

AICentral

Package Description

MyIA.SemanticKernel.Connectors.AI.MultiConnector

Extend your Semantic Kernel-powered apps with a fleet of specialized connectors, managed by a superior LLM as your fleet captain.

Musoq.DataSources.OpenAI

Package Description

GitHub repositories (3)

Showing the top 3 popular GitHub repositories that depend on SharpToken:

Repository Stars
microsoft/semantic-kernel
Integrate cutting-edge LLM technology quickly and easily into your apps
axzxs2001/Asp.NetCoreExperiment
原来所有项目都移动到**OleVersion**目录下进行保留。新的案例装以.net 5.0为主,一部分对以前案例进行升级,一部分将以前的工作经验总结出来,以供大家参考!
aiqinxuancai/TiktokenSharp
Token calculation for OpenAI models, using `o200k_base` `cl100k_base` `p50k_base` encoding.
Version Downloads Last updated
2.0.3 158,035 5/17/2024
2.0.2 49,273 4/8/2024
2.0.1 32,529 3/26/2024
1.2.33 2,462 3/25/2024
1.2.17 105,206 2/19/2024
1.2.16 9,113 2/15/2024
1.2.15 28,339 2/5/2024
1.2.14 188,642 12/10/2023
1.2.13 184 12/10/2023
1.2.12 269,380 9/12/2023
1.2.10 6,827 9/7/2023
1.2.8 28,548 8/28/2023
1.2.7 3,869 8/23/2023
1.2.6 36,006 8/2/2023
1.2.5 2,045 8/1/2023
1.2.2 24,926 7/1/2023
1.2.1 195 7/1/2023
1.1.3 212 7/1/2023
1.0.30 3,459 6/26/2023
1.0.29 808 6/25/2023
1.0.28 70,374 4/25/2023
1.0.27 2,256 4/20/2023
1.0.26 267 4/18/2023
1.0.25 16,404 3/28/2023
1.0.24 263 3/28/2023
1.0.23 268 3/28/2023
1.0.22 271 3/28/2023
1.0.21 269 3/28/2023
1.0.20 267 3/28/2023
1.0.19 298 3/28/2023
1.0.18 298 3/28/2023
1.0.17 289 3/28/2023
1.0.16 277 3/28/2023
1.0.12 273 3/28/2023
1.0.11 276 3/28/2023
1.0.2 5,304 7/1/2023