fountain_engine

Core algorithms for fountain code encoding and decoding.

What It Provides

• Encoder / Decoder: Generic fountain code encoder and decoder that work with any code scheme implementing the CodeScheme trait.
• Traits: CodeScheme and DataOperator — implement these to define custom fountain codes and data backends.
• BinaryMatrix: Packed GF(2) matrix utilities used by the solver stack.

Architecture

The engine is data-free by design. Instead of operating on data directly, the encoder and decoder emit a sequence of Operation values that a DataOperator executes on actual data vectors. This separation enables:

• In-memory operation (VecDataOperater in fountain_utility)
• I/O logging (IoDataOperator in fountain_utility)
• Network streaming or any custom backend

Solver

Encoding and decoding use SystemSolver: belief propagation, inactivation, and Gaussian elimination over a sparse master-system representation. This is the only solver in the published 2.x crate.

Profiling / timing introspection and staging solver experiments are monorepo development facilities and are not part of this published package.

Dependency

[dependencies]
fountain_engine = "2.0.1"

License

This crate is dual-licensed:

1. AGPL-3.0 — Free for open-source use. See LICENSE-AGPL.
2. Commercial — For proprietary use without AGPL obligations. See LICENSE-COMMERCIAL.

Copyright (c) 2025 Shenghao Yang. All rights reserved.