OpenccNetLib 1.1.0

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
• Add-On CLI 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 Kyujitai
• 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

using OpenccNetLib;

var opencc = new Opencc("s2t");

// Initial conversion
string result = opencc.Convert("动态切换转换方式");
Console.WriteLine(result);  // Output: 動態切換轉換方式

// Switch config using string
opencc.Config = "t2s";  // Also valid: 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

// Switch config using enum (recommended for safety and autocomplete)
opencc.SetConfig(OpenccConfig.S2T);
result = opencc.Convert("动态切换转换方式");
Console.WriteLine(result);  // Output: 動態切換轉換方式

// Invalid config falls back to "s2t"
opencc.Config = "invalid_config";
Console.WriteLine(opencc.GetLastError());  // Output: Invalid config provided: invalid_config. Using default 's2t'.

💡 Tips

• Use OpenccConfig enum for compile-time safety and IntelliSense support.
• Use GetLastError() to check if fallback occurred due to an invalid config.
• You can also validate config strings with Opencc.IsValidConfig("t2tw").

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)

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 1.1.0

BenchmarkDotNet v0.15.2 · .NET 9.0.8 · Windows 11 · RyuJIT AVX2
Test: BM_Convert_Sized · Warmup + 10 Iterations

⏱ Relative Performance Chart

✅ Highlights

• ✅ Preallocated StringBuilder delivers consistent performance across all input sizes, minimizing reallocations.
• 🚀 Inclusive splitting reduces ConvertBy() calls, boosting throughput for segmented processing.
• 🔁 Parallel processing automatically engages for large workloads (≥16 segments, ≥2000 chars), taking full advantage of multicore CPUs.
• 📉 Memory usage scales linearly with input size — from ~5 KB to ~85 MB — with no unpredictable spikes.
• 🧠 GC pressure remains stable and predictable, even at 1M characters:
  • Gen0: ~7.7K collections
  • Gen1: ~2.25K collections
  • Gen2: ~625 collections
    All within expected and manageable ranges.
• ⚡ Fast warm startup, suitable for both CLI batch conversion and responsive GUI usage.
• ✨ OpenccNetLib 1.1.0 is fully production-ready for high-performance, large-scale Chinese text conversion.

API Reference

Opencc Class

🔧 Constructor

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

🔁 Conversion Methods

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

• string S2T(string inputText, bool punctuation = false)

• string T2S(string inputText, bool punctuation = false)

• string S2Tw(string inputText, bool punctuation = false)

• string Tw2S(string inputText, bool punctuation = false)

• string S2Twp(string inputText, bool punctuation = false)

• string Tw2Sp(string inputText, bool punctuation = false)

• string S2Hk(string inputText, bool punctuation = false)

• string Hk2S(string inputText, bool punctuation = false)

• string T2Tw(string inputText)

• string T2Twp(string inputText)

• string Tw2T(string inputText)

• string Tw2Tp(string inputText)

• string T2Hk(string inputText)

• string Hk2T(string inputText)

• string T2Jp(string inputText)

• string Jp2T(string inputText)

⚙️ Configuration

• string Config { get; set; }
  Gets or sets the current config string. Invalid configs fallback to "s2t" and update error status.
• void SetConfig(string config)
  Set the config using a string (e.g., "tw2sp"). Falls back to "s2t" if invalid.
• void SetConfig(OpenccConfig configEnum)
  Set the config using a strongly typed OpenccConfig enum. Recommended for safety and IDE support.
• string GetConfig()
  Returns the current config string (e.g., "s2tw").
• string GetLastError()
  Returns the most recent error message, if any, from config setting.

📋 Validation and Helpers

• static bool IsValidConfig(string config)
  Checks whether the given string is a valid config name.
• static IReadOnlyCollection<string> GetSupportedConfigs()
  Returns the list of all supported config names as strings.
• static bool TryParseConfig(string config, out OpenccConfig result)
  Converts a valid config string to the corresponding OpenccConfig enum. Returns false if invalid.
• static int ZhoCheck(string inputText)
  Detects whether the input is likely Simplified Chinese (2), Traditional Chinese (1), or neither (0).

Dictionary Data

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

Add-On CLI 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              Read original text from file <input>
  -o, --output             Write original text to file <output>
  -c, --config (REQUIRED)  Conversion configuration: s2t|s2tw|s2twp|s2hk|t2s|tw2s|tw2sp|hk2s|jp2t|t2jp
  -p, --punct              Punctuation conversion. [default: False]
  --in-enc                 Encoding for input: UTF-8|UNICODE|GBK|GB2312|BIG5|Shift-JIS [default: UTF-8]
  --out-enc                Encoding for output: UTF-8|UNICODE|GBK|GB2312|BIG5|Shift-JIS [default: UTF-8]
  -?, -h, --help           Show help and usage information

OpenccNet office

Description:
  Convert Office documents or Epub using OpenccNetLib.

Usage:
  OpenccNet office [options]

Options:
  -i, --input              Input Office document <input>
  -o, --output             Output Office document <output>
  -c, --config (REQUIRED)  Conversion configuration: s2t|s2tw|s2twp|s2hk|t2s|tw2s|tw2sp|hk2s|jp2t|t2jp
  -p, --punct              Enable punctuation conversion. [default: False]
  -f, --format             Force Office document format: docx | xlsx | pptx | odt | ods | odp | epub
  --keep-font              Preserve font names in Office documents [default: true]. Use --keep-font:false to disable. [default: True]
  --auto-ext               Auto append correct extension to Office output files [default: true]. Use --auto-ext:false to disable. [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.