🐼 Ailuropoda: Automate CBOR for C Structs

✨ Tired of writing tedious, error-prone boilerplate C code for CBOR serialization and deserialization?

Ailuropoda is your solution! This powerful Python tool automatically generates robust C functions to encode and decode your C structs into Concise Binary Object Representation (CBOR), seamlessly integrating with the TinyCBOR library.

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🚀 Why Ailuropoda?

Manually handling CBOR for complex C data structures is a time sink. Ailuropoda eliminates this pain, letting you focus on your core logic while it handles the serialization boilerplate.

Key Features:

• Automated Boilerplate: Generates encode_MyStruct() and decode_MyStruct() functions for each struct in your C header files.
• TinyCBOR Integration: Produces C code fully compatible with the CborEncoder and CborValue APIs from the TinyCBOR library.
• Comprehensive Type Support: Handles a wide range of C types:
  • Basic integers (int, uint64_t, char, etc.)
  • Floating-point numbers (float, double)
  • Booleans (bool)
  • Fixed-size character arrays (char name[64]) as CBOR text strings.
  • Character pointers (char* email, const char* notes) as CBOR text strings.
  • Nested structs.
  • Fixed-size arrays of primitive types or nested structs.
• Ready-to-Use Output: Generates a dedicated output directory containing:
  • cbor_generated.h and cbor_generated.c with your encode/decode functions.
  • A CMakeLists.txt file to easily compile the generated code and link against TinyCBOR.
  • Helper functions for cbor2json and json2cbor conversion, simplifying data inspection and interoperability.
• Simplified Development: Define your data structures in C headers, and let Ailuropoda handle the rest!

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🛠️ How It Works

Ailuropoda leverages pycparser to parse your C header file's Abstract Syntax Tree (AST). It identifies struct definitions and their members, then intelligently generates the corresponding C encoding and decoding functions.

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📦 Installation

Ailuropoda is available on PyPI, making installation straightforward.

Global Installation (Recommended for CLI Tools)

For convenient command-line usage without managing virtual environments manually, pipx is highly recommended:

pip install pipx
pipx install ailuropoda

Virtual Environment Installation

For project-specific dependencies:

Using uv (recommended for fast dependency management):

# First, install uv (if you haven't already):
# curl -LsSf https://astral.sh/uv/install.sh | sh

# Create and synchronize the virtual environment
uv venv
uv pip install ailuropoda

# Activate the environment (optional, uv run/exec handle this)
source .venv/bin/activate

Using pip (standard installation):

python -m venv .venv
source .venv/bin/activate
pip install ailuropoda

Using pipenv:

pip install pipenv
pipenv install ailuropoda
pipenv shell

🚀 Usage

Ailuropoda provides a command-line interface ailuropoda (or ailuropoda.cbor_codegen if running via uv run directly from source).

1. Run the code generator:

   Concrete Example:

   # Generate CBOR code for tests/my_data.h into the 'generated_cbor' directory
   # Using pipx:
   pipx run ailuropoda tests/my_data.h --output-dir ./generated_cbor
   
   # Using uvx:
   uvx ailuropoda tests/my_data.h --output-dir ./generated_cbor
   

   This will create a directory (e.g., generated_cbor) containing cbor_generated.h, cbor_generated.c, and a CMakeLists.txt file.

2. Integrate with your CMake project: Add the generated directory to your CMakeLists.txt:

   add_subdirectory(generated_cbor)
   target_link_libraries(your_app PRIVATE cbor_generated tinycbor)
   

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⚠️ Assumptions and Limitations

• C Preprocessing: For complex header files with many #include directives or macros, it's recommended to preprocess the header first (e.g., using gcc -E your_header.h) and then pass the preprocessed output to Ailuropoda.
• Memory Management for Pointers: For char* and other pointer types during decoding, the generated C code does not perform dynamic memory allocation (malloc). It assumes that the pointer members in your struct are already pointing to sufficiently large, allocated buffers. You are responsible for managing this memory.
• Unsupported C Constructs:
  • union types are not supported.
  • Function pointers are detected but skipped.
  • Multi-dimensional arrays beyond the first dimension are not fully supported for complex types.
  • Flexible array members are not supported.
• Error Handling: The generated C functions return false on any CBOR encoding/decoding error.
• CBOR Map Keys: Struct member names are used directly as CBOR map keys (text strings).
• Anonymous Structs: Anonymous struct definitions that are not part of a typedef or a named member are skipped.

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🤝 Contributing

We welcome contributions! Feel free to open issues or pull requests on our GitHub repository: jvishnefske/Ailuropoda

📄 License

This project is licensed under the BSD 3-Clause License.

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💡 For Developers

If you are contributing to Ailuropoda or running its tests from the source repository, follow these steps:

Development Setup

Navigate to your project directory and synchronize the virtual environment with core and development dependencies:

cd /path/to/Ailuropoda
uv sync --dev

Python Environment and Project Configuration

Ailuropoda follows modern Python packaging and dependency management best practices, leveraging uv and pyproject.toml.

• pyproject.toml (PEP 621): This file serves as the single source of truth for project metadata, dependencies, and build system configuration. It adheres to PEP 621, making the project easily discoverable and installable by tools like pip, uv, or rye.
• uv for Virtual Environments: uv is used for fast dependency resolution and virtual environment management. Commands like uv sync ensure all project dependencies (and development dependencies with --dev) are installed into an isolated virtual environment.
• Running Scripts: Always use uv run python <script_path> (or uv run <module_name>) to execute project scripts. This automatically activates the virtual environment and ensures the correct Python interpreter and installed packages are used. This approach eliminates the need for manual source .venv/bin/activate or manipulating the PATH environment variable, promoting a cleaner and more reliable development workflow.

C/C++ Integration Testing with Pytest

The project includes robust integration tests (tests/integration/test_full_pipeline.py) to ensure the entire code generation, compilation, and execution pipeline works as expected.

• Pytest Fixtures: Pytest fixtures are extensively used to set up and tear down the testing environment:
  • tmp_path: Provides a unique, temporary directory for each test, ensuring isolation and preventing test interference. All generated files (C code, build artifacts) are placed here.
  • tinycbor_install_path: This fixture handles the compilation and installation of the TinyCBOR C library, which Ailuropoda's generated code depends on. It ensures TinyCBOR is available in a known location for subsequent compilation steps.
  • setup_test_environment: This orchestrates the core integration steps:
    1. It calls ailuropoda.cbor_codegen.generate_cbor_code to generate the cbor_generated.h, cbor_generated.c, and CMakeLists.txt files into the tmp_path.
    2. It then uses subprocess to invoke cmake and make within the generated directory to compile the generated C code, linking it against the TinyCBOR library.
    3. Finally, it compiles a simple C test harness (e.g., c_test_harness_simple_data.c.jinja) that uses the generated CBOR functions, creating an executable binary.
• subprocess Module: Python's subprocess module is used to execute external commands, such as cmake, make, and the compiled C test binaries. This allows the Python tests to drive the C build and execution process.
• Verification: After execution, the tests can read the output of the C binary (e.g., serialized CBOR data, deserialized values) and compare it against expected results, ensuring correctness of the generated code.

This setup provides a comprehensive way to validate Ailuropoda's output and its compatibility with the target C environment.

🚧 TODO / Future Enhancements

We're continuously working to improve Ailuropoda. Here are some planned features:

• CBOR to JSON / JSON to CBOR Helpers: Implement optional C helper functions for converting between CBOR and JSON, simplifying debugging and interoperability.
• Dynamic Memory Management for Pointers: Enhance char* and other pointer decoding to optionally handle dynamic memory allocation (malloc/free) for decoded data, reducing the burden on the user.
• Union Type Support: Add support for C union types.
• Enum Type Support: Generate appropriate CBOR representations for C enum types.
• Improved Error Handling: Provide more granular error codes and messages in the generated C functions.
• Advanced Array Support: Explore support for multi-dimensional arrays and flexible array members.