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Copy pathVersion3 HuffmanCodes.java
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433 lines (383 loc) · 11 KB
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import java.io.*;
import java.util.*;
import java.lang.*;
/**
* PROTOTYPE
*
*/
public class HuffmanCodes {
//Global Variables
private static ArrayList<String> flags = new ArrayList<String>();
private static ArrayList<File> files = new ArrayList<File>();
static final int DECISION_TAG = 0;
static final int VALUE_TAG = 1;
/**
* Abstract Node Class - Adapted From Piazza
*/
abstract class Node implements Comparable<Node> {
int value;
public Node(int value){
this.value = value;
}
public int compareTo(Node node2) {
return Integer.compare(this.value, node2.value);
}
public final Map<Byte, String> getAllCodes() {
Map<Byte, String> codeTable = new HashMap<>();
this.putCodes(codeTable, "");
return codeTable;
}
public final Map<String , Byte> getAllCodes2() {
Map<String, Byte> codeTable = new HashMap<>();
this.putCodes2("", codeTable);
return codeTable;
}
//Abstract Methods
protected abstract void writeTo(BitOutputStream out) throws IOException;
protected abstract void putCodes(Map<Byte, String> table, String path);
protected abstract void putCodes2(String path,Map<String, Byte> table);
public abstract byte next(BitInputStream in) throws IOException;
}
/**
* Value Node Class - Adapted from Piazza
*/
class ValueNode extends Node{
final byte value;
public ValueNode(byte bvalue, int value) {
super(value);
this.value = bvalue;
}
@Override
public void writeTo(BitOutputStream out) throws IOException {
out.writeBit(VALUE_TAG);
out.writeByte(value);
}
@Override
protected void putCodes(Map<Byte, String> table, String path) {
table.put(value, path);
}
@Override
protected void putCodes2(String path, Map<String, Byte> table) {
table.put(path, value);
}
@Override
public byte next(BitInputStream in) throws IOException {
return value;
}
}
/**
* Decision Node Class - Adapted from Piazza
*/
class DecisionNode extends Node{
Node leftNode;
Node rightNode;
public void writeTo(BitOutputStream out) throws IOException {
out.writeBit(DECISION_TAG);
leftNode.writeTo(out);
rightNode.writeTo(out);
}
DecisionNode(Node leftNode , Node rightNode){
super(leftNode.value+rightNode.value);
this.leftNode = leftNode;
this.rightNode = rightNode;
}
@Override
protected void putCodes(Map<Byte, String> table, String path) {
leftNode.putCodes(table, path + "0");
rightNode.putCodes(table, path + "1");
}
@Override
public byte next(BitInputStream in) throws IOException {
Node branch;
if (in.readBit() == 0)
branch = leftNode;
else
branch = rightNode;
return branch.next(in);
}
@Override
protected void putCodes2(String path, Map<String, Byte> table) {
leftNode.putCodes2(path + "0" , table);
rightNode.putCodes2(path + "1", table);
}
}
private Node readTree(BitInputStream in) throws IOException{
int tag = in.readBit();
if (tag == 0)
{
Node left = readTree(in);
Node right = readTree(in);
return new DecisionNode(left, right);
}
else
{
byte value = (byte)in.readByte();
return new ValueNode(value, 0);
}
}
/**
* This code was provided by Mac
*/
private static final Map<String, String> escapedLiterals = new HashMap<>();
static{
escapedLiterals.put("\n", "\'\\n\'");
escapedLiterals.put("\r", "\'\\r\'");
escapedLiterals.put("\r", "\'\\r\'");
escapedLiterals.put("\\", "\'\\\\\'");
escapedLiterals.put("\'", "\'\\\'\'");
}
/**
* This code was provided by Mac
*/
private static String asASCIILiteral(byte asciiValue)
{
String convertedStr = new String(new byte[] {asciiValue});
String literal = escapedLiterals.get(convertedStr);
if (literal == null){
literal = String.format("\'%s\'", convertedStr);
}
return literal;
}
/**
* Build Tree Method using a Priority Queue
*/
private Node buildTree(Map<Byte, Integer> freq){
PriorityQueue<Node> bTree = buildForest(freq);
if(bTree.size() == 1)
bTree.add(bTree.peek());
while (bTree.size() > 1){
DecisionNode n = new DecisionNode(bTree.remove(), bTree.remove());
bTree.add(n);
}
return bTree.remove();
}
/**
* BuildForest Method Using a Priority Queue
*/
private PriorityQueue<Node> buildForest(Map<Byte, Integer> freq){
PriorityQueue<Node> bForest = new PriorityQueue<>(freq.size());
for (Map.Entry<Byte, Integer> entry: freq.entrySet()){
bForest.add(new ValueNode(entry.getKey(), entry.getValue()));
}
return bForest;
}
/**
* The encode method counts the frequency of each byte and then builds a binary tree.
* The main purpose of the method is to encode what originally was the input.
*/
private void encode(BitInputStream in, BitOutputStream out) throws IOException
{
byte[] data = in.allBytes();
final Map<Byte, Integer> freq = freqCount(data);
freqPrint(freq);
Node HuffTree = buildTree(freq);
int lengthInput = data.length;
out.writeInt(lengthInput);
HuffTree.writeTo(out);
int headBits = out.tally();
Map<Byte, String> codeTable = HuffTree.getAllCodes();
CodePrint(codeTable);
System.out.println();
for (int i = 0; i < data.length; ++i)
{
//System.out.println("Here");
String codes = codeTable.get(data[i]);
for (int idx = 0; idx < codes.length(); ++idx){
if (codes.charAt(idx) == '1'){
//System.out.print("1");
out.writeBit(1);
}
else
{
//System.out.print("0");
out.writeBit(0);
}
}
}
out.close();
SequencePrint(data, codeTable);
int encodingBits = out.tally() - headBits;
int outputLength = out.bytesNeeded();
double saved = outputLength / (double)lengthInput;
System.out.printf(" input: %d bytes [%d bits]%n",lengthInput, lengthInput * 8);
System.out.printf("output: %d bytes [header: %d bits; encoding: %d bits]%n", outputLength, headBits, encodingBits);
System.out.printf("output/input size: %.4f%%%n", saved * 100.0);
}
/**
* "Reverse Engineering" method
* Reads header in your encoded file, construct the tree and/or Huffman
* table that relates encodings to symbols/characters.
* Reads bits from the rest of the file one bit at a time, and keep reading bits until
* you can properly access your data structure with the encoding mappings in it.
*/
private void decode(BitInputStream in, BitOutputStream out) throws IOException
{
int originalSize = in.readInt();
Node tree = readTree(in);
Map<String , Byte> codeTable = tree.getAllCodes2();
//System.out.printf("original size: %d%n", originalSize);
for (int i = 0; i < originalSize; ++i)
{
boolean finish = true;
String code = "";
while(finish){
code = code + in.readBit();
if(codeTable.containsKey(code))
{
byte ch = codeTable.get(code);
out.writeByte(ch);
finish = false;
}
}
}
out.close();
//int numDecoded = 0;
//while(numDecoded < originalSize)
//{
//initialize empty string str
//String str = null;
//while(!codeTable.containsKey(str))
//{
//readBit
//int bitR = in.readBit();
//String str2 = Integer.toString(bitR);
//str = str + str2.substring(str2.length() - 1);
//concatenate bit to str
//}
//add codeTable.get(str) to file
//out.writeByte(codeTable.get(str).byteValue());
//increment numDecoded
// numDecoded++;
//}
}
/**
* Method that prints the frequencies chart which represents how often a letter is represented
*/
private void freqPrint(final Map<Byte, Integer> freq)
{
if (flags.contains("-F"))
{
System.out.printf("FREQUENCY TABLE%n");
List<Byte> toSortList = new ArrayList<Byte>(freq.keySet());
Collections.sort(toSortList);
Collections.sort(toSortList, new Comparator<Byte>()
{
public int compare(Byte firstByte, Byte secondByte)
{
Integer frequencies = Integer.compare(freq.get(firstByte), freq.get(secondByte));
return frequencies;
}
});
for (Byte value: toSortList){
int count = freq.get(value);
System.out.printf("%s: %s%n", asASCIILiteral(value), count);
}
}
else
return;
}
/**
* Using a HashMap that takes count of the frequencies
*/
private Map<Byte, Integer> freqCount (byte[] data)
{
Map<Byte, Integer> freqMap = new HashMap<>();
for (int i = 0; i < data.length; ++i){
Integer val = freqMap.get(data[i]);
if (val == null){
val = 0;
}
freqMap.put(data[i], val + 1);
}
return freqMap;
}
/**
* Method that prints the code chart which has the binary representation of each char/letter
*/
private void CodePrint(final Map<Byte, String> codeTable)
{
if (flags.contains("-C")){
System.out.printf("CODES%n");
List<Byte> toSortList = new ArrayList<Byte>(codeTable.keySet());
Collections.sort(toSortList, new Comparator<Byte>(){
public int compare(Byte firstB, Byte secondB){
String firstCode = codeTable.get(firstB);
String secondCode = codeTable.get(secondB);
int lengthFirst = Integer.compare(firstCode.length(), secondCode.length());
if (lengthFirst == 0){
return firstCode.compareTo(secondCode);
}
return lengthFirst;
}
});
for (Byte value: toSortList){
String code = codeTable.get(value);
System.out.printf("\"%s\" -> %s%n", code, asASCIILiteral(value));
}
}
else
return;
}
/**
* Method that prints the encoded sequence
*/
private void SequencePrint(byte[] data, Map<Byte, String> codeTable)
{
if (flags.contains("-B")){
System.out.printf("ENCODED SEQUENCE%n");
for (int i = 0; i < data.length; ++i){
String code = codeTable.get(data[i]);
System.out.print(code);
}
System.out.println();
}
else
return;
}
/**
* Modify the file passed in by the argument using the classes provided BitInputStream and BitOutputStream
* Print an error if these files do not exist
*/
public void fileModification()
{
try{
BitInputStream in = new BitInputStream(files.get(0));
BitOutputStream out = new BitOutputStream(files.get(1));
if (flags.contains("-e"))
encode(in, out);
if(flags.contains("-d"))
decode(in, out);
}
catch (Exception e)
{
System.err.printf("Error: %s%n", e.getMessage());
System.exit(1);
}
}
/**
* Store the flags in an Arraylist of flags , and store the files in an Arraylist of files
* By storing the flags into an ArrayList the program will know what methods to execute
*/
public static void main(String[] args){
/*if(args[0].equals("-d"))
{
try
{
BitInputStream in = new BitInputStream(new File(args[1]));
BitOutputStream out = new BitOutputStream(new File(args[2]));
HuffmanCodes hw = new HuffmanCodes();
hw.decode(in,out);
}
}*/
/*else
{*/
for(int i = 0; i < args.length ; i++){
if(args[i].contains("-e") || args[i].contains("-d") || args[i].contains("-F") || args[i].contains("-C") || args[i].contains("-B") )
flags.add(args[i]);
if(!args[i].contains("-e") && !args[i].contains("-d") && !args[i].contains("-F") && !args[i].contains("-C") && !args[i].contains("-B") )
files.add(new File(args[i]));
}
HuffmanCodes application = new HuffmanCodes();
application.fileModification();
}
}