//Author: Andrew Donofrio and Connor Maloney

//Date: 3/26/14

//Huff.java - zips text file

//

//Run this program through the interactions window. "run Huff filename.txt"

import java.util.*;

import java.io.*;

import java.lang.*;

class Node {

public char characters;

public int frequency;

public Node left, right;

public Node(char c, int f) {

characters = c;

frequency = f;

}

public Node() {

}

class CompareFrequency implements Comparator<Node> {

public int compare(Node x, Node y) { //compares two nodes, returns difference between the two

int freqOne = x.frequency;

int freqTwo = y.frequency;

return freqOne-freqTwo;

}

}

public class Huff {

public static PriorityQueue<Node> pq;

public static HashMap<Character, String> compressionMove;

public static void main(String[] args) throws IOException {

// Read file

// File myFile = new File(args[0]);

// FileReader reader = new FileReader(myFile);

FileIOC savedFile = new FileIOC();

FileReader contentsOutput = savedFile.openInputFile(args[0]);

Map<Character, Integer> hashmap = new HashMap<Character, Integer>();

String inputtext = ""; //input file text

//counts frequency of each character

while(true) {

int inputfile = contentsOutput.read();

if(inputfile == -1)

break;

char current = (char) inputfile;

inputtext = inputtext + current;

if(hashmap.containsKey(current))

hashmap.put(current, hashmap.get(current) + 1);

else{

hashmap.put(current, 1);

}

}

// Add nodes to PQ

pq = new PriorityQueue<Node>(200, new CompareFrequency()); //uses PriorityQueue<> - 200 signifies the number of spots for unique characters. 200 is a very generous number

int size = 0;

for(Character char1 : hashmap.keySet()) {

pq.add(new Node(char1, hashmap.get(char1))); //now it's on the priority queue

size++; //increments the size by 1 to continue the for loop

}

// Root of Tree

Node root = makeTree(size);

// Prints out what is input and its length

System.out.println("");

System.out.println("The original text is: ");

System.out.println(inputtext);

System.out.println("Original text is " + inputtext.length()*8 + " bits");

//Frequency Chart

System.out.println("");

System.out.println("Frequency of each character: ");

System.out.println(hashmap);

//Symbol Table - representation of each letter (most frequently used letters should have the shortest representation)

System.out.println("The Symbol Table: ");

buildTable(root);

String compressed = compress(inputtext);

//Binary output - shows the compressed text - should be put into the zip file

System.out.println("");

System.out.println("The compressed text is: ");

System.out.println(compressed);

//System.out.println("Bit Converted (2nd) :" + toBinaryString(compressed));

System.out.println("The compressed text is " + compressed.length() + " bits");

//Metrics on the compressed text - added to describe the change from the original text

System.out.println("");

System.out.println("The difference in bits between compressed output and original text is " + ((inputtext.length()*8)-compressed.length()) + " bits");

System.out.println("That is an overall size change of " + ((compressed.length() - ((inputtext.length()*8)-compressed.length()) + "%")));

savedFile.openBinaryOutputFile();

// binaryOutFileName("mississippi.txt", "mississippi.zip");

// binaryOut(binaryOutFileName);

// contentsOutput.write(compressed.getBytes()); //ERROR IS HERE

BinaryOut binaryout = savedFile.openBinaryOutputFile();

binaryout.write(compressed); //SHOULD write the compressed string to the newly created zip file (mississippi.txt > mississippi.zip in test case)

}

// Goes through tree - traverseTree - assigns 0s and 1s to alternating branches

public static void traverseTree(Node node1, String string1) {

if(node1 == null) //node isnt leaf

return;

traverseTree(node1.left, string1+"0"); //node is left leaf so add a 0

traverseTree(node1.right, string1+"1"); //node is right leaf so add a 1

//The 0s and 1s pattern describe the path created to the leaves which translate to the representations of characters in the symbol table

//Assigns the values to the characters

if(node1.characters != '\0') {

System.out.println("'" + node1.characters + "' : " + string1); //prints the values for each number

compressionMove.put(node1.characters, string1);

}

}

//Tree with least common characters as left children

public static Node makeTree(int length) {

Node one, two; //initialize the nodes

for(int i = 1; i <= length-1; i++) {

//creates new node in tree

Node three = new Node();

//poll returns head of queue

three.left = one = pq.poll();

//poll returns head of queue

three.right = two = pq.poll();

//new node is the sum of the other two

three.frequency = one.frequency + two.frequency;

pq.add(three);

}

return pq.poll();

}

// Compression table

public static void buildTable(Node root) {

compressionMove = new HashMap<Character, String>();

traverseTree(root, new String());

}

// Compression - creates string of 0s and 1s

public static String compress(String string2) {

String string3 = new String();

for(int i = 0; i < string2.length(); i++)

string3 = string3 + compressionMove.get(string2.charAt(i));

return string3;

}

}

}