Multi-Compression System in C

A modular, algorithm-driven file compression and decompression system implemented in C, supporting both text data and BMP image formats through multiple specialized techniques.

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Overview

This project presents a unified framework that applies appropriate compression algorithms based on input file type, demonstrating practical implementation of core concepts from data structures, algorithm design, and digital image processing.

The system supports both compression and decompression, ensuring efficient storage and accurate data reconstruction.

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Key Features

• Multi-format support: Text (.txt) and Bitmap Images (.bmp)
• Integration of multiple compression algorithms within a single system
• Automated selection of compression technique based on file type
• Lossless compression for text data using Huffman Coding
• Modular and maintainable C codebase
• Build automation using Makefile

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Algorithms & Techniques

Huffman Coding (Text Compression)

• Frequency-based encoding using binary tree construction
• Generates optimal prefix codes
• Ensures lossless compression

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Bit Plane Slicing (8-bit BMP Images)

• Decomposes image into individual bit planes

• Supports:

  • MSB-based compression
  • Full bit-plane slicing

• Enables efficient grayscale image handling

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Discrete Cosine Transform (DCT) (32-bit BMP Images)

• Converts spatial data into frequency components
• Reduces high-frequency information
• Inspired by standard image compression techniques

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Project Structure

SPL-1/
├── .github/                      # GitHub configuration (copilot-instructions.md)
├── .vscode/                      # VS Code configuration
├── Makefile                      # Build automation file
├── README.md                     # Project documentation
│
├── Main Modules (Core Logic)
│   ├── main.c                    # Entry point of the program
│   ├── huffman.c / .h            # Huffman coding implementation
│   ├── bmp_compress.c / .h       # Bit Plane Slicing logic
│   ├── dct_compress.c / .h       # Discrete Cosine Transform logic
│   ├── text_compress.c / .h      # Text compression interface
│   └── color_image.c / .h        # Image processing utilities
│
├── Data Types & Utilities
│   └── types.c / .h              # Common data structures and definitions
│
├── Build Artifacts (Generated Files)
│   ├── *.o                       # Compiled object files
│   └── compressor                # Final executable
│
└── Test / Data Files
    ├── article.txt               # Sample text for testing
    ├── lena.bmp                  # Sample image (grayscale)
    ├── lena2.bmp                 # Additional test image
    ├── lenaColor.jpg             # Reference image
    └── output2.ppm               # Output test file

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Build & Execution

Build using Makefile

make

Run the Program

./compressor

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Technical Highlights

• Implementation of tree-based encoding (Huffman)
• Low-level handling of BMP file formats
• Application of frequency-domain transformation (DCT)
• Clear separation of modules for scalability and maintainability
• Use of Makefile for efficient build management

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Limitations

• Supports only .txt and .bmp formats for compression

• Image processing restricted to:

  • 8-bit grayscale BMP
  • 32-bit color BMP

• DCT implementation is simplified and not fully JPEG-compliant

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Future Enhancements

• Extend support to additional formats (PNG, JPEG)
• Integrate advanced algorithms (RLE, LZW)
• Improve compression efficiency and performance
• Add graphical user interface (GUI)

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Author

Prottasha Saha Ayoishee BSSE in Software Engineering University of Dhaka

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Summary

This project demonstrates the integration of multiple compression strategies within a single system, reflecting strong understanding of algorithm design, file processing, and system-level programming in C.

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