/* James Little 5-5-01 
   I hope this is one of the last programs I have to write in this course.
*/

package jlittle_ex9.compress;

import java.io.*;
import java.util.*;
import util241.*;

public class Compress {
    private static BufferedInputStream reader;
    private static BitStreamOutputStream writer;
    private static String outputfilename = "";

    public static void main(String [] args){
	String inputfilename = null;	

	Compress a = new Compress();

	try{
	    if (args.length != 0){
		inputfilename = args[0];
		outputfilename = inputfilename + ".LZW";

		// open input streams
		FileInputStream inFile = new FileInputStream(inputfilename);
		BufferedInputStream reader = new BufferedInputStream(inFile);

		//open output streams
		FileOutputStream outFile = new FileOutputStream(outputfilename);
		BufferedOutputStream outBuf = new BufferedOutputStream(outFile);
		writer = new BitStreamOutputStream(outBuf, 12);

	    }else{
		reader = new BufferedInputStream(System.in);
		writer = new BitStreamOutputStream(System.out, 12);
	
	    }
	   
	}catch(IOException e){System.out.println("Error: " + e + "\nFilename : "+inputfilename);}
	a.compress();	
    }
    
    // compression routine
    public void compress(){
	
	int MAX_VALUE = 4000;
	Vector string_table = new Vector();

	for(int i=0; i<256; i++){
	    string_table.add(String.valueOf((char)i));
	}

	//	System.out.println("I am now compressing...");
	int next_code = 256, intStr = 0, intChar=0;
	
	try{
	    intStr = reader.read();
	    if(intStr!=-1){
		String aString = String.valueOf((char)intStr);
		String nextChar = "";
		int i = 0;
		
		while((intChar = reader.read())!=-1){
		    
		    nextChar = String.valueOf((char)intChar);
		    if(string_table.contains(aString + nextChar)){
			aString = aString + nextChar;
		    }else{
			i = string_table.indexOf(aString);
			writer.writeBitField(i);
			string_table.add(aString + nextChar);
			aString = nextChar;
		    } // end if		
		    if(string_table.size()>MAX_VALUE){
			string_table.removeAllElements();	
			for(int j=0; j<256; j++){
			    string_table.add(String.valueOf((char)j));
			}
		    }
		} // end while
	    
		i = string_table.indexOf(aString);
		writer.writeBitField(i); // write a string
	    }// end of initial is the file empty?? if
	    writer.close();
	    reader.close();
	} catch(IOException e){ 
	    System.out.println("ERROR: " + e);
	    System.exit(1);
	}

	//for(int j=256; j<string_table.size() ; j++){
	//	System.out.println("\t"+string_table.size());
	//}
	

    } // end compress
} // end App