Huffman code in binary(java)?

Question

I have successfully built my Huffman tree and I have a method that traverses the the tree and saves the Huffman code for each character as a String of 1s and 0s:

    public void encode(HuffmanNode node, String aux) {

    if (!node.isLeaf()) {
        if (node.getLeft() != null) {
            aux = aux + "0";
            encode(node.getLeft(), aux);
        }
        if (node.getRight() != null){
            aux = aux + "1";
            encode(node.getRight(), aux);
        }
    } else {
        //building a character-code pair and add to keyMap
        keyMap.put(new Character(node.getCh()), aux);
    }
}

where keyMap is a HashMap that maps each character to its Huffman-code.

However, saving Huffman-codes as Strings only increases the size of the encoded file instead of compressing it, since you need a String of 0s and 1s to represent a single character. So is there a way to save the code as binary bits instead of String? Thx in advance.

Jim Garrison Jim Garrison · Accepted Answer · 2018-06-20T04:08:16

Don't use a String to store the binary result, use a java.util.BitSet.

It does exactly what you want, allowing you to set individual bits by index position.

When you are ready to extract the value in binary you can use toByteArray().

Huffman code in binary(java)?

1 Answers