File Compressor using Huffman Coding (DS Project)

A simple and efficient file compression and decompression tool written in C using Huffman Coding, developed by Geeks 5.

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Overview

This project demonstrates how lossless data compression works using Huffman encoding.

The program:

• Reads a file (text or binary)
• Calculates frequency of each byte
• Builds a Huffman Tree
• Encodes data into compressed format (.g5)
• Decodes compressed file back to original (.txt)

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Concept Used

• Huffman Coding (Greedy Algorithm)
• Binary Trees
• Min Heap (Priority Queue)
• Bit-level file handling

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Project Structure

.
├── main.c          → CLI interface and program flow
├── freq.h          → Frequency calculation  
├── huffman.h       → Tree + heap + code generation
├── compress.h      → Compression logic
├── decompress.h    → Decompression logic
└── README.md

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How It Works

Compression

1. Read input file

2. Count frequency of each character

3. Build Huffman Tree

4. Generate binary codes

5. Store:

   • Total characters
   • Encoded Huffman tree
   • Compressed data

Output file → .g5

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Decompression

1. Read .g5 file
2. Reconstruct Huffman Tree
3. Decode bit stream
4. Write original data

Output file → .txt

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🛠️ Build Instructions

Compile using GCC:

gcc main.c -o main

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Usage

Compress

./main <filename> --compress

Example:

./main sample.txt --compress

Then enter output name → creates:

output.g5

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Decompress

./main <filename> --decompress

Example:

./main sample.g5 --decompress

Then enter output name → creates:

output.txt

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Example

gcc main.c -o main
./main input.txt --compress
./main input.g5 --decompress

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Features

• Lossless compression
• Custom .g5 format
• Bit-level encoding
• Tree serialization
• Works on any file type

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Limitations

• Output filename must be entered manually
• No GUI (command line only)
• Limited error handling
• Not optimized for very large files

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Future Improvements

• Add command-line flags for output file
• Improve error handling
• Add Makefile
• Add GUI interface
• Optimize compression ratio

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Team

Geeks 5

• Bharath
• Hrushikesh
• Mukesh
• Raghav
• Shanmukh

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Notes

• Compression appends .g5 automatically
• Decompression appends .txt automatically
• Empty files are not supported

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Reference

Basic implementation inspired from standard Huffman Coding concepts and data structures.

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💡 Final Thought

This project is a practical implementation of how real-world compression systems work at a low level using bits and trees.