OpenccNetLib 1.0.2

OpenccNet

OpenccNetLib is a fast and efficient .NET library for converting Chinese text, offering support for Simplified ↔ Traditional, Taiwan, Hong Kong, and Japanese Kanji variants. Built with inspiration from OpenCC, this library is designed to integrate seamlessly into modern .NET projects with a focus on performance and minimal memory usage.

Table of Contents

• Installation
• Usage
• API Reference
• Dictionary Files
• Add-On Tools
• License

Features

• Fast, multi-stage conversion using static dictionary caching
• Supports:
  • Simplified ↔ Traditional Chinese
  • Traditional (Taiwan) ↔ Simplified/Traditional
  • Traditional (Hong Kong) ↔ Simplified/Traditional
  • Japanese Kanji Shinjitai ↔ Traditional Kyojitai
• Optional punctuation conversion
• Thread-safe and suitable for parallel processing
• .NET Standard 2.0 compatible

Installation

• Add the library to your project via NuGet or reference the source code directly.
• Add required dependencies of dictionary files to library root.
  • dicts\dictionary_maxlength.zstd Default dictionary file.
  • dicts\*.* Others dictionary files for different configurations.

Install via NuGet:

dotnet add package OpenccNetLib

Or, clone and include the source files in your project.

Usage

Basic Example

using OpenccNetLib;
var opencc = new Opencc("s2t"); // Simplified to Traditional 
string traditional = opencc.Convert("汉字转换测试"); 
Console.WriteLine(traditional);
// Output: 漢字轉換測試

Supported Configurations

Example: Convert with Punctuation

var opencc = new Opencc("s2t"); 
string result = opencc.Convert("“汉字”转换。", punctuation: true);
Console.WriteLine(result);
// Output: 「漢字」轉換。

Example: Switching Config Dynamically

var opencc = new Opencc("s2t"); 
string result = opencc.Convert("动态切换转换方式");
Console.WriteLine(result);  // Output: 動態切換轉換方式
opencc.Config = "t2s";  // or opencc.SetConfig("t2s");
result = opencc.Convert("動態切換轉換方式");
Console.WriteLine(result);  // Output: 动态切换转换方式

Direct API Methods

You can also use direct methods for specific conversions:

using OpenccNetLib;
var opencc = new Opencc();
opencc.S2T("汉字");      
// Simplified to Traditional opencc.T2S("漢字");      
// Traditional to Simplified opencc.S2Tw("汉字");     
// Simplified to Taiwan Traditional opencc.T2Jp("漢字");     
// Traditional to Japanese Kanji
// ...and more

Error Handling

If an error occurs (e.g., invalid config), use:

string error = opencc.GetLastError();
Console.WriteLine(error); // Output the last error message

Language Detection

Detect if a string is Simplified, Traditional, or neither:

using OpenccNetLib;
int result = Opencc.ZhoCheck("汉字"); // Returns 2 for Simplified, 1 for Traditional, 0 for neither
Console.WriteLine(result); // Output: 2 (for Simplified)

Dictionary Files

Ensure the necessary dictionary files are included in your project. Add the following to your .csproj.
In most case, it is auto-set when package added from Nuget:

<ItemGroup>
  <None Update="dicts\dictionary_maxlength.zstd">
    <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    <Pack>true</Pack>
    <PackagePath>contentFiles\any\any\dicts\dictionary_maxlength.zstd</PackagePath>
  </None>
  
</ItemGroup>

Using Custom Dictionary

Library default is zstd compressed dictionary Lexicon. It can be changed to custom dictionary (JSON, CBOR or "baseDir/*.txt") prior to instantiate Opencc():

using OpenccNetLib;
Opencc.UseCustomDictionary(DictionaryLib.FromDicts()) // Init only onece, dicts from baseDir "./dicts/"
var opencc = new Opencc("s2t"); // Simplified to Traditional 
string traditional = opencc.Convert("汉字转换测试"); 
Console.WriteLine(traditional); // Output: 漢字轉換測試

Performance

• Uses static dictionary caching and thread-local buffers for high throughput.
• Suitable for batch and parallel processing scenarios.

📊 Benchmark Results – OpenccNetLib 1.0.2

BenchmarkDotNet v0.15.0 · .NET 9.0.6 · Windows 11 · RyuJIT AVX2
Test: BM_Convert_Sized · Warmup + 3 Iterations

⏱ Relative Performance Chart

✅ Highlights

• Roundlist and dictionary preloading eliminates lazy overhead.
• Warm startup is fast, even for large inputs.
• Memory usage and GC pressure scale predictably.
• CLI and GUI now feel instant for most users.

API Reference

Opencc Class

• Opencc(string config = null)
  Create a new converter with the specified configuration.

• string Convert(string inputText, bool punctuation = false)
  Convert text according to the current config.

• string S2T(string inputText, bool punctuation = false)
  Simplified → Traditional

• string T2S(string inputText, bool punctuation = false)
  Traditional → Simplified

• ... (see source for all conversion methods)

• string GetLastError()
  Get the last error message.

• string Config { get; set; }
  Gets or sets the current OpenCC config. Invalid configs fall back to "s2t" and update the error message.

• void SetConfig(string config)
  Sets the current config. Falls back to "s2t" if invalid.

• string GetConfig()
  Returns the current config value.

• static bool IsValidConfig(string config)
  Checks whether the given config string is supported.

• static IReadOnlyCollection<string> GetSupportedConfigs()
  Returns the list of valid OpenCC config names.

• static int ZhoCheck(string inputText)
  Detect if text is Simplified, Traditional, or neither.

Dictionary Data

• Dictionaries are loaded and cached on first use.
• Data files are expected in the dicts/ directory (see DictionaryLib for details).

Add-On Tools (Separated from OpenccNetLib)

OpenccNet dictgen

Description:
  Generate OpenccNetLib dictionary files.

Usage:
  OpenccNet dictgen [options]

Options:
  -f, --format <cbor|json|zstd>  Dictionary format: [zstd|cbor|json] [default: zstd]
  -o, --output <output>          Output filename. Default: dictionary_maxlength.<ext>
  -b, --base-dir <base-dir>      Base directory containing source dictionary files [default: dicts]
  -?, -h, --help                 Show help and usage information

OpenccNet convert

Description:
  Convert text using OpenccNetLib configurations.

Usage:
  OpenccNet convert [options]

Options:
  -i, --input <input>               Read original text from file <input>.
  -o, --output <output>             Write converted text to file <output>.
  -c, --config <config> (REQUIRED)  Conversion configuration: [s2t|s2tw|s2twp|s2hk|t2s|tw2s|tw2sp|hk2s|jp2t|t2jp]
  -p, --punct                       Punctuation conversion: True|False [default: False]
  --in-enc <in-enc>                 Encoding for input: [UTF-8|UNICODE|GBK|GB2312|BIG5|Shift-JIS] [default: UTF-8]
  --out-enc <out-enc>               Encoding for output: [UTF-8|UNICODE|GBK|GB2312|BIG5|Shift-JIS] [default: UTF-8]
  --office                          Convert Office documents (.docx | .xlsx | .pptx | .odt | .ods | .odp | .epub) [default: False]
  --format <format>                 Force Office document format: docx | xlsx | pptx | odt | ods | odp | epub
  --keep-font                       Preserve original font names in Office documents during conversion.
                                    Default: true. To disable, use: --keep-font:false [default: True]
  --auto-ext                        Automatically append correct Office document extension to output file if missing (e.g., .docx, .xlsx).
                                    Default: true. To disable, use: --auto-ext:false [default: True]
  -?, -h, --help                    Show help and usage information

Project That Use OpenccNetLib

• OpenccNetLibGui : A GUI application for OpenccNetLib, providing a user-friendly interface for Chinese text conversion.

License

This project is licensed under the MIT License. See the LICENSE file for details.

OpenccNet is not affiliated with the original OpenCC project, but aims to provide a compatible and high-performance solution for .NET developers.