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Huffman Coding

Huffman Coding a powerful Java module to compress and decompress a file in which codewords have integer numbers of bit lengths.

  • Shrinks the file size on the back-end while it can perfectly reconstruct the data when it decompresses.
  • Has a significant reduced size for medium size text file consisting of alphanumeric characters.
  • Compression process and decompression process are independent stages. The compressed file can be decoded any time into the original file.

How It Works

  1. Huffman Coding has two concrete classes of HuffmanEncode and HuffmanDecode which inherit the HuffmanTree class which maintains the Huffman tree which can be used to trace the characters it stores.
  2. Huffman Coding serializes the non-static contents of HuffmanTree into the prefix of the file and appends the Huffman code sequence.
  3. In encoding process, a queue is utilized to group 8 bits and to write the corresponding byte to the file each at a time.
  4. In decoding process, a queue is utilized to reconstruct the binary sequence of 8 bits from the read-in byte each at a time.
  5. The compressed file contains a pseudo EOF which marks the end of effective contents in a file and ignores the remaining bytes.

Installation

Add (clone) this repo to your Java's project as a submodule under your Java resource folder and give a meaningful name. For example, add submodule in the libs directory and name it Huffman, using the url:

git submodule add https://github.com/Jackiebibili/Huffman_Coding.git libs/Huffman

Usage

Encode a File (Data Compression)

  1. Create an instance of the class HuffmanEncode by using the overloaded constructor, passing a file path as the argument.
  2. Call the encode method in the HuffmanEncode with the compressed file path.
  3. The compressed file will be saved in the file path you specified.

Decode a File (Data Decompression)

  1. Create an instance of the class HuffmanDecode by using the overloaded constructor, passing a file path as the argument.
  2. Call the decode method in the HuffmanDecode with the extracted file path.
  3. The extracted (original) file will be saved in the file path you specified.

Requirements

Java 9 and above