ZeroBit - A high-performance file compressor written in modern C++, leveraging a multi-stage pipeline-including Burrows-Wheeler Transform (BWT), Move-To-Front (MTF), Zero Run-Length Encoding (RLE), and an adaptive context-mixing range coder-to achieve efficient, lossless compression. Specifically created for small files.

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📋 Table of Contents

• ⚙️ Features
• 📂 Usage
• 🔍 File Format
• 📚 Algorithms
• 👤 Author

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⚙️ Features

• Bidirectional: Supports both compression and decompression.
• Adaptive Modeling: Combines multiple context models (byte, bit, match, LZP) with online mixing.
• Single-header Implementation: Minimal dependencies; requires only C++17 and Qt 6.9.0.
• Portable: Uses std::filesystem for cross-platform file handling.

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📂 Usage

• Best for: Text files with a lot of numerical values.
• Bad for: Text files with a lot of non-structured text.

🔍 File Format

Each compressed file's header is structured as follows:

• Original file size (uint64_t)
• Block length (uint32_t)
• BWT primary index (uint32_t)
• RLE symbol count (uint32_t)
• Compressed data size (uint32_t)
• Range-coded payload (bytes)

This design enables streaming decompression without loading the entire file into memory.

📚 Algorithms

Stage	Technique	Purpose
1	Burrows–Wheeler Transform (BWT)	Increases symbol locality
2	Move-To-Front (MTF)	Exposes runs of low symbols
3	Zero Run-Length Encoding (RLE)	Efficiently encodes zero runs
4	Adaptive Context Models + Mixer	Learns bitwise patterns dynamically
5	Range Coding	Optimal entropy encoding

👤 Author

Developed by Stefan Rusev ([email protected])