import java.io.*;
import java.util.zip.*;

public class Compress {

//-------------------------------------------------------------------
// main entry point. Check args. Determine whether to compress or decomp.
//-------------------------------------------------------------------
protected void go(String[] args) throws IOException {
String filename;
FileInputStream input;
FileOutputStream output;

	// check command line argument is present
	if ( args.length != 1 ) {
		System.out.println("Usage: Compress <file>");
		System.exit(10);
	}

	// open input file
	filename = args[0];
	input  = new FileInputStream(filename);

	// see whether we should compress or decompress
	if ( ! filename.endsWith(".crunched") ) {
		output = new FileOutputStream(filename + ".crunched");

		System.out.println("Compressing "+ filename +" to "+
										   filename +".crunched ...");
		compress(input, output);
	} else {
		String baseName = filename.substring(0, filename.length()-9);
		output = new FileOutputStream(baseName + ".out");

		System.out.println("Decompressing "+ filename +" to "+
											 baseName +".out ...");
		decompress(input, output);
	}
	System.out.println("Done.");
}
//-------------------------------------------------------------------
// Compress/Decompress an input stream to an output stream
//-------------------------------------------------------------------
protected void compress(InputStream in, OutputStream out) throws IOException {
Deflater cruncher;
DeflaterOutputStream crunchedOut;

	cruncher    = new Deflater();		// default will do for us
	crunchedOut = new DeflaterOutputStream(out, cruncher);
	copyStream(in, crunchedOut);
}
//-------------------------------------------------------------------
protected void decompress(InputStream in, OutputStream out) throws IOException {
Inflater uncruncher;
InflaterInputStream crunchedIn;

	uncruncher = new Inflater();		// default will do for us
	crunchedIn = new InflaterInputStream(in, uncruncher);
	copyStream(crunchedIn, out);
}
//-------------------------------------------------------------------
// Copy an input stream to an output stream.
//-------------------------------------------------------------------
protected void copyStream(InputStream in, OutputStream out) throws IOException {
int aByte;

	boolean eof = false;
	while ( ! eof ) {
		aByte = in.read();
		eof = ( aByte == -1 );
		if ( ! eof ) {
			out.write( (byte) aByte);
		}
	}

	in.close();
	out.close();
}
//-------------------------------------------------------------------
// static main delegates work to object.
//-------------------------------------------------------------------
public static void main (String[] args) {
	try {
		new Compress().go(args);
	} catch (IOException ioError) {
		System.out.println("An I/O error occurred: " + ioError);
	}
}
} // End of Class Compress