JpegEncoder.java 58.3 KB
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// Version 1.0a
// Copyright (C) 1998, James R. Weeks and BioElectroMech.
// Visit BioElectroMech at www.obrador.com.  Email James@obrador.com.

// See license.txt for details about the allowed used of this software.
// This software is based in part on the work of the Independent JPEG Group.
// See IJGreadme.txt for details about the Independent JPEG Group's license.

// This encoder is inspired by the Java Jpeg encoder by Florian Raemy,
// studwww.eurecom.fr/~raemy.
// It borrows a great deal of code and structure from the Independent
// Jpeg Group's Jpeg 6a library, Copyright Thomas G. Lane.
// See license.txt for details.

// westfeld
// todo:
// switch for multi-volume embedding
// indeterministic embedding
// password switch
package james;
import crypt.Permutation;
import crypt.F5Random;

import java.applet.Applet;
import java.awt.*;
import java.awt.image.*;
import java.io.*;
import java.util.*;
import java.lang.*;

/*
* JpegEncoder - The JPEG main program which performs a jpeg compression of
* an image.
*/

public class JpegEncoder extends Frame
{
    Thread runner;
    BufferedOutputStream outStream;
    Image image;
    JpegInfo JpegObj;
    Huffman Huf;
    DCT dct;
    int imageHeight, imageWidth;
    int Quality;
    int code;
    public static int[] jpegNaturalOrder = {
          0,  1,  8, 16,  9,  2,  3, 10,
         17, 24, 32, 25, 18, 11,  4,  5,
         12, 19, 26, 33, 40, 48, 41, 34,
         27, 20, 13,  6,  7, 14, 21, 28,
         35, 42, 49, 56, 57, 50, 43, 36,
         29, 22, 15, 23, 30, 37, 44, 51,
         58, 59, 52, 45, 38, 31, 39, 46,
         53, 60, 61, 54, 47, 55, 62, 63,
        };
    // westfeld
    FileInputStream embeddedData = null;
    String password = null;
    int n = 0;

    public JpegEncoder(Image image, int quality, OutputStream out, String comment)
    {
                MediaTracker tracker = new MediaTracker(this);
                tracker.addImage(image, 0);
                try {
                        tracker.waitForID(0);
                }
                catch (InterruptedException e) {
// Got to do something?
                }
        /*
        * Quality of the image.
        * 0 to 100 and from bad image quality, high compression to good
        * image quality low compression
        */
        Quality=quality;

        /*
        * Getting picture information
        * It takes the Width, Height and RGB scans of the image. 
        */
        JpegObj = new JpegInfo(image, comment);

        imageHeight=JpegObj.imageHeight;
        imageWidth=JpegObj.imageWidth;
        outStream = new BufferedOutputStream(out);
        dct = new DCT(Quality);
        Huf=new Huffman(imageWidth,imageHeight);
    }

    public void setQuality(int quality) {
        dct = new DCT(quality);
    }

    public int getQuality() {
        return Quality;
    }

    public void Compress(FileInputStream embeddedData, String password) {
    	this.embeddedData = embeddedData;
    	this.password = password;
	Compress();
    }

    public void Compress() {
        WriteHeaders(outStream);
        WriteCompressedData(outStream);
        WriteEOI(outStream);
        try {
                outStream.flush();
        } catch (IOException e) {
                System.out.println("IO Error: " + e.getMessage());
        }
    }

    public void WriteCompressedData(BufferedOutputStream outStream) {
        int offset, i, j, r, c,a ,b, temp = 0;
        int comp, xpos, ypos, xblockoffset, yblockoffset;
        float inputArray[][];
        float dctArray1[][] = new float[8][8];
        double dctArray2[][] = new double[8][8];
        int dctArray3[] = new int[8*8];

        /*
         * This method controls the compression of the image.
         * Starting at the upper left of the image, it compresses 8x8 blocks
         * of data until the entire image has been compressed.
         */

        int lastDCvalue[] = new int[JpegObj.NumberOfComponents];
        int zeroArray[] = new int[64]; // initialized to hold all zeros
        int Width = 0, Height = 0;
        int nothing = 0, not;
        int MinBlockWidth, MinBlockHeight;
// This initial setting of MinBlockWidth and MinBlockHeight is done to
// ensure they start with values larger than will actually be the case.
        MinBlockWidth = ((imageWidth%8 != 0) ? (int) (Math.floor((double) imageWidth/8.0) + 1)*8 : imageWidth);
        MinBlockHeight = ((imageHeight%8 != 0) ? (int) (Math.floor((double) imageHeight/8.0) + 1)*8: imageHeight);
        for (comp = 0; comp < JpegObj.NumberOfComponents; comp++) {
                MinBlockWidth = Math.min(MinBlockWidth, JpegObj.BlockWidth[comp]);
                MinBlockHeight = Math.min(MinBlockHeight, JpegObj.BlockHeight[comp]);
        }
        xpos = 0;
	// westfeld
	// Before we enter these loops, we initialise the
	// coeff for steganography here:
	int shuffledIndex = 0;
	int coeffCount = 0;
        for (r = 0; r < MinBlockHeight; r++) {
           for (c = 0; c < MinBlockWidth; c++) {
              for (comp = 0; comp < JpegObj.NumberOfComponents; comp++) {
                 for(i = 0; i < JpegObj.VsampFactor[comp]; i++) {
		    for(j = 0; j < JpegObj.HsampFactor[comp]; j++) {
			coeffCount += 64;
                     }
                  }
               }
            }
        }
        int coeff[] = new int[coeffCount];

System.out.println("DCT/quantisation starts");
System.out.println(imageWidth+" x "+imageHeight);
        for (r = 0; r < MinBlockHeight; r++) {
           for (c = 0; c < MinBlockWidth; c++) {
               xpos = c*8;
               ypos = r*8;
               for (comp = 0; comp < JpegObj.NumberOfComponents; comp++) {
                  Width = JpegObj.BlockWidth[comp];
                  Height = JpegObj.BlockHeight[comp];
                  inputArray = (float[][]) JpegObj.Components[comp];

                  for(i = 0; i < JpegObj.VsampFactor[comp]; i++) {
                     for(j = 0; j < JpegObj.HsampFactor[comp]; j++) {
                        xblockoffset = j * 8;
                        yblockoffset = i * 8;
                        for (a = 0; a < 8; a++) {
                           for (b = 0; b < 8; b++) {

// I believe this is where the dirty line at the bottom of the image is
// coming from.  I need to do a check here to make sure I'm not reading past
// image data.
// This seems to not be a big issue right now. (04/04/98)

// westfeld - dirty line fixed, Jun 6 2000
			int ia = ypos*JpegObj.VsampFactor[comp]
			    + yblockoffset + a;
			int ib = xpos*JpegObj.HsampFactor[comp]
			    + xblockoffset + b;
			if (imageHeight/2*JpegObj.VsampFactor[comp]<=ia)
			    ia = imageHeight/2*JpegObj.VsampFactor[comp]-1;
			if (imageWidth/2*JpegObj.HsampFactor[comp]<=ib)
			    ib = imageWidth/2*JpegObj.HsampFactor[comp]-1;
                              //dctArray1[a][b] = inputArray[ypos + yblockoffset + a][xpos + xblockoffset + b];
                              dctArray1[a][b] = inputArray[ia][ib];
                           }
                        }
// The following code commented out because on some images this technique
// results in poor right and bottom borders.
//                        if ((!JpegObj.lastColumnIsDummy[comp] || c < Width - 1) && (!JpegObj.lastRowIsDummy[comp] || r < Height - 1)) {
                           dctArray2 = dct.forwardDCT(dctArray1);
                           dctArray3 = dct.quantizeBlock(dctArray2, JpegObj.QtableNumber[comp]);
//                        }
//                        else {
//                           zeroArray[0] = dctArray3[0];
//                           zeroArray[0] = lastDCvalue[comp];
//                           dctArray3 = zeroArray;
//                        }
			// westfeld
			// For steganography, all dct
			// coefficients are collected in
			// coeff[] first. We do not encode
			// any Huffman Blocks here (we'll do
			// this later).
			System.arraycopy(dctArray3, 0, coeff, shuffledIndex, 64);
			shuffledIndex += 64;

                     }
                  }
               }
            }
        }
System.out.println("got "+coeffCount+" DCT AC/DC coefficients");
	int _changed=0;
	int _embedded=0;
	int _examined=0;
	int _expected=0;
	int _one=0;
	int _large=0;
	int _thrown=0;
	int _zero=0;
	for (i=0; i<coeffCount; i++) {
	    if ((i%64)==0) continue;
	    if (coeff[i]==1) _one++;
	    if (coeff[i]==-1) _one++;
	    if (coeff[i]==0) _zero++;
	}
	_large=coeffCount-_zero-_one-coeffCount/64;
	_expected=_large+(int)(0.49*_one);
//
// System.out.println("zero="+_zero);
System.out.println("one="+_one);
System.out.println("large="+_large);
//
System.out.println("expected capacity: "+_expected+" bits");
System.out.println("expected capacity with");
for (i=1; i<8; i++) {
    int usable, changed, n;
    n = (1<<i)-1;
    usable = _expected*i/n-_expected*i/n%n;
    changed = coeffCount-_zero-coeffCount/64;
    changed = changed*i/n-changed*i/n%n;
    changed = n*changed/(n+1)/i;
    //
    changed = _large-_large%(n+1);
    changed = (changed+_one+_one/2-_one/(n+1))/(n+1);
    usable /= 8;
    if (usable == 0) break;
    if (i==1)
	System.out.print("default");
    else
	System.out.print("(1, "+n+", "+i+")");
    System.out.println(" code: "+usable+" bytes (efficiency: "
	    +((usable*8)/changed)+"."+(((usable*80)/changed)%10)
	    +" bits per change)");
}

	// westfeld
	if (embeddedData != null) {
	// Now we embed the secret data in the permutated sequence.
System.out.println("Permutation starts");
	    F5Random random = new F5Random(password.getBytes());
	    Permutation permutation = new Permutation(coeffCount, random);
	    int nextBitToEmbed=0;
	    int byteToEmbed=0;
	    int availableBitsToEmbed=0;
	    // We start with the length information.  Well,
	    // the length information it is more than one
	    // byte, so this first "byte" is 32 bits long.
	    try {
		byteToEmbed=embeddedData.available();
	    } catch (Exception e) {
		e.printStackTrace();
	    }
	    System.out.print("Embedding of "+(byteToEmbed*8+32)+" bits ("
		+byteToEmbed+"+4 bytes) ");
	    // We use the most significant byte for the 1 of n
	    // code, and reserve one extra bit for future use.
	    if (byteToEmbed>0x007fffff)
		byteToEmbed=0x007fffff;
	    // We calculate n now
	    for (i=1; i<8; i++) {
		int usable, changed;
		n = (1<<i)-1;
		usable = _expected*i/n-_expected*i/n%n;
		usable /= 8;
		if (usable == 0) break;
		if (usable < byteToEmbed+4) break;
	    }
	    int k=i-1;
	    n=(1<<k)-1;
	    switch (n) {
	    case 0:
		System.out.println("using default code, file will not fit");
		n++;
		break;
	    case 1:
		System.out.println("using default code");
		break;
	    default:
		System.out.println("using (1, "+n+", "+k+") code");
	    }
	    byteToEmbed |= k<<24;	// store k in the status word
	    // Since shuffling cannot hide the distribution, the
	    // distribution of all bits to embed is unified by
	    // adding a pseudo random bit-string. We continue the random
	    // we used for Permutation, initially seeked with password.
	    byteToEmbed ^= random.getNextByte();
	    byteToEmbed ^= random.getNextByte()<<8;
	    byteToEmbed ^= random.getNextByte()<<16;
	    byteToEmbed ^= random.getNextByte()<<24;
	    nextBitToEmbed = byteToEmbed & 1;
	    byteToEmbed >>= 1;
	    availableBitsToEmbed=31;
	    _embedded++;
	    if (n > 1) {	// use 1 of n code
		int kBitsToEmbed;
		int extractedBit;
		int[] codeWord = new int[n];
		int hash;
		int startOfN=0;
		int endOfN=0;
		boolean isLastByte = false;
		// embed status word first
		for(i=0; i<coeffCount; i++) {
		    shuffledIndex = permutation.getShuffled(i);
		    if (shuffledIndex%64 == 0) continue; // skip DC coefficients
		    if (coeff[shuffledIndex] == 0) continue; // skip zeroes
		    if (coeff[shuffledIndex] > 0) {
			if ((coeff[shuffledIndex]&1) != nextBitToEmbed) {
			    coeff[shuffledIndex]--; // decrease absolute value
			    _changed++;
			}
		    } else {
			if ((coeff[shuffledIndex]&1) == nextBitToEmbed) {
			    coeff[shuffledIndex]++; // decrease absolute value
			    _changed++;
			}
		    }
		    if (coeff[shuffledIndex] != 0) {
			// The coefficient is still nonzero. We
			// successfully embedded "nextBitToEmbed".
			// We will read a new bit to embed now.
			if (availableBitsToEmbed==0)
			    break;	// statusword embedded.
			nextBitToEmbed = byteToEmbed & 1;
			byteToEmbed >>= 1;
			availableBitsToEmbed--;
			_embedded++;
		    } else _thrown++;
		}
		startOfN = i+1;
		// now embed the data using 1 of n code
embeddingLoop:
		do {
		    kBitsToEmbed = 0;
		    // get k bits to embed
		    for (i=0; i<k; i++) {
			if (availableBitsToEmbed==0) {
			    // If the byte of embedded text is
			    // empty, we will get a new one.
			    try {
				if (embeddedData.available()==0) {
				    isLastByte = true;
				    break;
				}
				byteToEmbed = embeddedData.read();
				byteToEmbed ^= random.getNextByte();
			    } catch (Exception e) {
				e.printStackTrace();
				break;
			    }
			    availableBitsToEmbed=8;
			}
			nextBitToEmbed = byteToEmbed & 1;
			byteToEmbed >>= 1;
			availableBitsToEmbed--;
			kBitsToEmbed |= nextBitToEmbed << i;
			_embedded++;
		    }
		    // embed k bits
		    do {
			j = startOfN;
			// fill codeWord[] with the indices of the
			// next n non-zero coefficients in coeff[]
			for (i=0; i<n; j++) {
			    if (j>=coeffCount) {
				// in rare cases the estimated capacity is too small
				System.out.println("Capacity exhausted.");
				break embeddingLoop;
			    }
			    shuffledIndex = permutation.getShuffled(j);
			    if (shuffledIndex%64 == 0) continue; // skip DC coefficients
			    if (coeff[shuffledIndex] == 0) continue; // skip zeroes
			    codeWord[i++]=shuffledIndex;
			}
			endOfN = j;
			hash = 0;
			for (i=0; i<n; i++) {
			    if (coeff[codeWord[i]] > 0)
				extractedBit = coeff[codeWord[i]]&1;
			    else
				extractedBit = 1-(coeff[codeWord[i]]&1);
			    if (extractedBit == 1)
				hash ^= i+1;
			}
			i = hash ^ kBitsToEmbed;
			if (i==0) break; // embedded without change
			i--;
			if (coeff[codeWord[i]]>0)
			    coeff[codeWord[i]]--;
			else
			    coeff[codeWord[i]]++;
			_changed++;
			if (coeff[codeWord[i]]==0) _thrown++;
		    } while (coeff[codeWord[i]]==0);
		    startOfN = endOfN;
		} while (!isLastByte);
	    } else {	// default code
		// The main embedding loop follows. It works on the
		// shuffled stream of coefficients.
		for(i=0; i<coeffCount; i++) {
		    shuffledIndex = permutation.getShuffled(i);
		    if (shuffledIndex%64 == 0) continue; // skip DC coefficients
		    if (coeff[shuffledIndex] == 0) continue; // skip zeroes
		    _examined++;
		    if (coeff[shuffledIndex] > 0) {
			if ((coeff[shuffledIndex]&1) != nextBitToEmbed) {
			    coeff[shuffledIndex]--; // decrease absolute value
			    _changed++;
			}
		    } else {
			if ((coeff[shuffledIndex]&1) == nextBitToEmbed) {
			    coeff[shuffledIndex]++; // decrease absolute value
			    _changed++;
			}
		    }
		    if (coeff[shuffledIndex] != 0) {
			// The coefficient is still nonzero. We
			// successfully embedded "nextBitToEmbed".
			// We will read a new bit to embed now.
			if (availableBitsToEmbed==0) {
			    // If the byte of embedded text is
			    // empty, we will get a new one.
			    try {
				if (embeddedData.available()==0) break;
				byteToEmbed=embeddedData.read();
				byteToEmbed ^= random.getNextByte();
			    } catch (Exception e) {
				e.printStackTrace();
				break;
			    }
			    availableBitsToEmbed=8;
			}
			nextBitToEmbed = byteToEmbed & 1;
			byteToEmbed >>= 1;
			availableBitsToEmbed--;
			_embedded++;
		    } else _thrown++;
		}
	    }
if (_examined > 0)
    System.out.println(_examined+" coefficients examined");
System.out.println(_changed+" coefficients changed (efficiency: "
	    +(_embedded/_changed)+"."+(((_embedded*10)/_changed)%10)
	    +" bits per change)");
System.out.println(_thrown+" coefficients thrown (zeroed)");
System.out.println(_embedded+" bits ("+_embedded/8+" bytes) embedded");
	}
System.out.println("Starting Huffman Encoding.");
	// Do the Huffman Encoding now.
	shuffledIndex=0;
        for (r = 0; r < MinBlockHeight; r++) {
           for (c = 0; c < MinBlockWidth; c++) {
              for (comp = 0; comp < JpegObj.NumberOfComponents; comp++) {
                 for(i = 0; i < JpegObj.VsampFactor[comp]; i++) {
		    for(j = 0; j < JpegObj.HsampFactor[comp]; j++) {
			System.arraycopy(coeff, shuffledIndex, dctArray3, 0, 64);
			Huf.HuffmanBlockEncoder(outStream, dctArray3,
			    lastDCvalue[comp], JpegObj.DCtableNumber[comp],
			    JpegObj.ACtableNumber[comp]);
			lastDCvalue[comp] = dctArray3[0];
			shuffledIndex += 64;
                    }
                 }
              }
           }
        }

        Huf.flushBuffer(outStream);
    }

    public void WriteEOI(BufferedOutputStream out) {
        byte[] EOI = {(byte) 0xFF, (byte) 0xD9};
        WriteMarker(EOI, out);
    }

    public void WriteHeaders(BufferedOutputStream out) {
        int i, j, index, offset, length;
        int tempArray[];

// the SOI marker
        byte[] SOI = {(byte) 0xFF, (byte) 0xD8};
        WriteMarker(SOI, out);

// The order of the following headers is quiet inconsequential.
// the JFIF header
        byte JFIF[] = new byte[18];
        JFIF[0] = (byte) 0xff;	// app0 marker
        JFIF[1] = (byte) 0xe0;
        JFIF[2] = (byte) 0x00;	// length
        JFIF[3] = (byte) 0x10;
        JFIF[4] = (byte) 0x4a;	// "JFIF"
        JFIF[5] = (byte) 0x46;
        JFIF[6] = (byte) 0x49;
        JFIF[7] = (byte) 0x46;
        JFIF[8] = (byte) 0x00;
        JFIF[9] = (byte) 0x01;	// 1.01
        JFIF[10] = (byte) 0x01;
        JFIF[11] = (byte) 0x00;
        JFIF[12] = (byte) 0x00;
        JFIF[13] = (byte) 0x01;
        JFIF[14] = (byte) 0x00;
        JFIF[15] = (byte) 0x01;
        JFIF[16] = (byte) 0x00;
        JFIF[17] = (byte) 0x00;

        if (JpegObj.getComment().equals("JPEG Encoder Copyright 1998, James R. Weeks and BioElectroMech.  "))
		JFIF[10] = (byte) 0x00;	// 1.00
        WriteArray(JFIF, out);

// Comment Header
        String comment = new String();
        comment = JpegObj.getComment();
        length = comment.length();
	if (length != 0) {
		byte COM[] = new byte[length + 4];
		COM[0] = (byte) 0xFF;
		COM[1] = (byte) 0xFE;
		COM[2] = (byte) ((length >> 8) & 0xFF);
		COM[3] = (byte) (length & 0xFF);
		java.lang.System.arraycopy(JpegObj.Comment.getBytes(), 0, COM, 4, JpegObj.Comment.length());
		WriteArray(COM, out);
	}

// The DQT header
// 0 is the luminance index and 1 is the chrominance index
        byte DQT[] = new byte[134];
        DQT[0] = (byte) 0xFF;
        DQT[1] = (byte) 0xDB;
        DQT[2] = (byte) 0x00;
        DQT[3] = (byte) 0x84;
        offset = 4;
        for (i = 0; i < 2; i++) {
                DQT[offset++] = (byte) ((0 << 4) + i);
                tempArray = (int[]) dct.quantum[i];
                for (j = 0; j < 64; j++) {
                        DQT[offset++] = (byte) tempArray[jpegNaturalOrder[j]];
                }
        }
        WriteArray(DQT, out);

// Start of Frame Header
        byte SOF[] = new byte[19];
        SOF[0] = (byte) 0xFF;
        SOF[1] = (byte) 0xC0;
        SOF[2] = (byte) 0x00;
        SOF[3] = (byte) 17;
        SOF[4] = (byte) JpegObj.Precision;
        SOF[5] = (byte) ((JpegObj.imageHeight >> 8) & 0xFF);
        SOF[6] = (byte) ((JpegObj.imageHeight) & 0xFF);
        SOF[7] = (byte) ((JpegObj.imageWidth >> 8) & 0xFF);
        SOF[8] = (byte) ((JpegObj.imageWidth) & 0xFF);
        SOF[9] = (byte) JpegObj.NumberOfComponents;
        index = 10;
        for (i = 0; i < SOF[9]; i++) {
                SOF[index++] = (byte) JpegObj.CompID[i];
                SOF[index++] = (byte) ((JpegObj.HsampFactor[i] << 4) + JpegObj.VsampFactor[i]);
                SOF[index++] = (byte) JpegObj.QtableNumber[i];
        }
        WriteArray(SOF, out);

// The DHT Header
        byte DHT1[], DHT2[], DHT3[], DHT4[];
        int bytes, temp, oldindex, intermediateindex;
        length = 2;
        index = 4;
        oldindex = 4;
        DHT1 = new byte[17];
        DHT4 = new byte[4];
        DHT4[0] = (byte) 0xFF;
        DHT4[1] = (byte) 0xC4;
        for (i = 0; i < 4; i++ ) {
                bytes = 0;
                DHT1[index++ - oldindex] = (byte) ((int[]) Huf.bits.elementAt(i))[0];
                for (j = 1; j < 17; j++) {
                        temp = ((int[]) Huf.bits.elementAt(i))[j];
                        DHT1[index++ - oldindex] =(byte) temp;
                        bytes += temp;
                }
                intermediateindex = index;
                DHT2 = new byte[bytes];
                for (j = 0; j < bytes; j++) {
                        DHT2[index++ - intermediateindex] = (byte) ((int[]) Huf.val.elementAt(i))[j];
                }
                DHT3 = new byte[index];
                java.lang.System.arraycopy(DHT4, 0, DHT3, 0, oldindex);
                java.lang.System.arraycopy(DHT1, 0, DHT3, oldindex, 17);
                java.lang.System.arraycopy(DHT2, 0, DHT3, oldindex + 17, bytes);
                DHT4 = DHT3;
                oldindex = index;
        }
        DHT4[2] = (byte) (((index - 2) >> 8)& 0xFF);
        DHT4[3] = (byte) ((index -2) & 0xFF);
        WriteArray(DHT4, out);


// Start of Scan Header
        byte SOS[] = new byte[14];
        SOS[0] = (byte) 0xFF;
        SOS[1] = (byte) 0xDA;
        SOS[2] = (byte) 0x00;
        SOS[3] = (byte) 12;
        SOS[4] = (byte) JpegObj.NumberOfComponents;
        index = 5;
        for (i = 0; i < SOS[4]; i++) {
                SOS[index++] = (byte) JpegObj.CompID[i];
                SOS[index++] = (byte) ((JpegObj.DCtableNumber[i] << 4) + JpegObj.ACtableNumber[i]);
        }
        SOS[index++] = (byte) JpegObj.Ss;
        SOS[index++] = (byte) JpegObj.Se;
        SOS[index++] = (byte) ((JpegObj.Ah << 4) + JpegObj.Al);
        WriteArray(SOS, out);

    }

    void WriteMarker(byte[] data, BufferedOutputStream out) {
        try {
                out.write(data, 0, 2);
        } catch (IOException e) {
                System.out.println("IO Error: " + e.getMessage());
        }
    }
        
    void WriteArray(byte[] data, BufferedOutputStream out) {
        int i, length;
        try {
                length = (((int) (data[2] & 0xFF)) << 8) + (int) (data[3] & 0xFF) + 2;
                out.write(data, 0, length);
        } catch (IOException e) {
                System.out.println("IO Error: " + e.getMessage());
        }
    }
}

// This class incorporates quality scaling as implemented in the JPEG-6a
// library.

 /*
 * DCT - A Java implementation of the Discreet Cosine Transform
 */

class DCT
{
    /**
     * DCT Block Size - default 8
     */
    public int N        = 8;

    /**
     * Image Quality (0-100) - default 80 (good image / good compression)
     */
    public int QUALITY = 80;

    public Object quantum[] = new Object[2];
    public Object Divisors[] = new Object[2];

    /**
     * Quantitization Matrix for luminace.
     */
    public int quantum_luminance[]     = new int[N*N];
    public double DivisorsLuminance[] = new double[N*N];

    /**
     * Quantitization Matrix for chrominance.
     */
    public int quantum_chrominance[]     = new int[N*N];
    public double DivisorsChrominance[] = new double[N*N];

    /**
     * Constructs a new DCT object. Initializes the cosine transform matrix
     * these are used when computing the DCT and it's inverse. This also
     * initializes the run length counters and the ZigZag sequence. Note that
     * the image quality can be worse than 25 however the image will be
     * extemely pixelated, usually to a block size of N.
     *
     * @param QUALITY The quality of the image (0 worst - 100 best)
     *
     */
    public DCT(int QUALITY)
    {
        initMatrix(QUALITY);
    }
                        

    /*
     * This method sets up the quantization matrix for luminance and
     * chrominance using the Quality parameter.
     */
    private void initMatrix(int quality)
    {
        double[] AANscaleFactor = { 1.0, 1.387039845, 1.306562965, 1.175875602,
                                    1.0, 0.785694958, 0.541196100, 0.275899379};
        int i;
        int j;
        int index;
        int Quality;
        int temp;

// converting quality setting to that specified in the jpeg_quality_scaling
// method in the IJG Jpeg-6a C libraries

        Quality = quality;
        if (Quality <= 0)
                Quality = 1;
        if (Quality > 100)
                Quality = 100;
        if (Quality < 50)
                Quality = 5000 / Quality;
        else
                Quality = 200 - Quality * 2;

// Creating the luminance matrix

        quantum_luminance[0]=16;
        quantum_luminance[1]=11;
        quantum_luminance[2]=10;
        quantum_luminance[3]=16;
        quantum_luminance[4]=24;
        quantum_luminance[5]=40;
        quantum_luminance[6]=51;
        quantum_luminance[7]=61;
        quantum_luminance[8]=12;
        quantum_luminance[9]=12;
        quantum_luminance[10]=14;
        quantum_luminance[11]=19;
        quantum_luminance[12]=26;
        quantum_luminance[13]=58;
        quantum_luminance[14]=60;
        quantum_luminance[15]=55;
        quantum_luminance[16]=14;
        quantum_luminance[17]=13;
        quantum_luminance[18]=16;
        quantum_luminance[19]=24;
        quantum_luminance[20]=40;
        quantum_luminance[21]=57;
        quantum_luminance[22]=69;
        quantum_luminance[23]=56;
        quantum_luminance[24]=14;
        quantum_luminance[25]=17;
        quantum_luminance[26]=22;
        quantum_luminance[27]=29;
        quantum_luminance[28]=51;
        quantum_luminance[29]=87;
        quantum_luminance[30]=80;
        quantum_luminance[31]=62;
        quantum_luminance[32]=18;
        quantum_luminance[33]=22;
        quantum_luminance[34]=37;
        quantum_luminance[35]=56;
        quantum_luminance[36]=68;
        quantum_luminance[37]=109;
        quantum_luminance[38]=103;
        quantum_luminance[39]=77;
        quantum_luminance[40]=24;
        quantum_luminance[41]=35;
        quantum_luminance[42]=55;
        quantum_luminance[43]=64;
        quantum_luminance[44]=81;
        quantum_luminance[45]=104;
        quantum_luminance[46]=113;
        quantum_luminance[47]=92;
        quantum_luminance[48]=49;
        quantum_luminance[49]=64;
        quantum_luminance[50]=78;
        quantum_luminance[51]=87;
        quantum_luminance[52]=103;
        quantum_luminance[53]=121;
        quantum_luminance[54]=120;
        quantum_luminance[55]=101;
        quantum_luminance[56]=72;
        quantum_luminance[57]=92;
        quantum_luminance[58]=95;
        quantum_luminance[59]=98;
        quantum_luminance[60]=112;
        quantum_luminance[61]=100;
        quantum_luminance[62]=103;
        quantum_luminance[63]=99;

        for (j = 0; j < 64; j++)
        {
                temp = (quantum_luminance[j] * Quality + 50) / 100;
                if ( temp <= 0) temp = 1;
                if (temp > 255) temp = 255;
                quantum_luminance[j] = temp;
        }
        index = 0;
        for (i = 0; i < 8; i++) {
                for (j = 0; j < 8; j++) {
// The divisors for the LL&M method (the slow integer method used in
// jpeg 6a library).  This method is currently (04/04/98) incompletely
// implemented.
//                        DivisorsLuminance[index] = ((double) quantum_luminance[index]) << 3;
// The divisors for the AAN method (the float method used in jpeg 6a library.
                        DivisorsLuminance[index] = (double) ((double)1.0/((double) quantum_luminance[index] * AANscaleFactor[i] * AANscaleFactor[j] * (double) 8.0));
                        index++;
                }
        }


// Creating the chrominance matrix

        quantum_chrominance[0]=17;
        quantum_chrominance[1]=18;
        quantum_chrominance[2]=24;
        quantum_chrominance[3]=47;
        quantum_chrominance[4]=99;
        quantum_chrominance[5]=99;
        quantum_chrominance[6]=99;
        quantum_chrominance[7]=99;
        quantum_chrominance[8]=18;
        quantum_chrominance[9]=21;
        quantum_chrominance[10]=26;
        quantum_chrominance[11]=66;
        quantum_chrominance[12]=99;
        quantum_chrominance[13]=99;
        quantum_chrominance[14]=99;
        quantum_chrominance[15]=99;
        quantum_chrominance[16]=24;
        quantum_chrominance[17]=26;
        quantum_chrominance[18]=56;
        quantum_chrominance[19]=99;
        quantum_chrominance[20]=99;
        quantum_chrominance[21]=99;
        quantum_chrominance[22]=99;
        quantum_chrominance[23]=99;
        quantum_chrominance[24]=47;
        quantum_chrominance[25]=66;
        quantum_chrominance[26]=99;
        quantum_chrominance[27]=99;
        quantum_chrominance[28]=99;
        quantum_chrominance[29]=99;
        quantum_chrominance[30]=99;
        quantum_chrominance[31]=99;
        quantum_chrominance[32]=99;
        quantum_chrominance[33]=99;
        quantum_chrominance[34]=99;
        quantum_chrominance[35]=99;
        quantum_chrominance[36]=99;
        quantum_chrominance[37]=99;
        quantum_chrominance[38]=99;
        quantum_chrominance[39]=99;
        quantum_chrominance[40]=99;
        quantum_chrominance[41]=99;
        quantum_chrominance[42]=99;
        quantum_chrominance[43]=99;
        quantum_chrominance[44]=99;
        quantum_chrominance[45]=99;
        quantum_chrominance[46]=99;
        quantum_chrominance[47]=99;
        quantum_chrominance[48]=99;
        quantum_chrominance[49]=99;
        quantum_chrominance[50]=99;
        quantum_chrominance[51]=99;
        quantum_chrominance[52]=99;
        quantum_chrominance[53]=99;
        quantum_chrominance[54]=99;
        quantum_chrominance[55]=99;
        quantum_chrominance[56]=99;
        quantum_chrominance[57]=99;
        quantum_chrominance[58]=99;
        quantum_chrominance[59]=99;
        quantum_chrominance[60]=99;
        quantum_chrominance[61]=99;
        quantum_chrominance[62]=99;
        quantum_chrominance[63]=99;

        for (j = 0; j < 64; j++)
        {
                temp = (quantum_chrominance[j] * Quality + 50) / 100;
                if ( temp <= 0) temp = 1;
                if (temp >= 255) temp = 255;
                quantum_chrominance[j] = temp;
        }
        index = 0;
        for (i = 0; i < 8; i++) {
                for (j = 0; j < 8; j++) {
// The divisors for the LL&M method (the slow integer method used in
// jpeg 6a library).  This method is currently (04/04/98) incompletely
// implemented.
//                        DivisorsChrominance[index] = ((double) quantum_chrominance[index]) << 3;
// The divisors for the AAN method (the float method used in jpeg 6a library.
                        DivisorsChrominance[index] = (double) ((double)1.0/((double) quantum_chrominance[index] * AANscaleFactor[i] * AANscaleFactor[j] * (double)8.0));
                        index++;
                }
        }

// quantum and Divisors are objects used to hold the appropriate matices

        quantum[0] = quantum_luminance;
        Divisors[0] = DivisorsLuminance;
        quantum[1] = quantum_chrominance;
        Divisors[1] = DivisorsChrominance;


    }

    /*
     * This method preforms forward DCT on a block of image data using
     * the literal method specified for a 2-D Discrete Cosine Transform.
     * It is included as a curiosity and can give you an idea of the
     * difference in the compression result (the resulting image quality)
     * by comparing its output to the output of the AAN method below.
     * It is ridiculously inefficient.
     */

// For now the final output is unusable.  The associated quantization step
// needs some tweaking.  If you get this part working, please let me know.

    public double[][] forwardDCTExtreme(float input[][])
    {
        double output[][] = new double[N][N];
        double tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
        double tmp10, tmp11, tmp12, tmp13;
        double z1, z2, z3, z4, z5, z11, z13;
        int i;
        int j;
        int v, u, x, y;
        for (v = 0; v < 8; v++) {
                for (u = 0; u < 8; u++) {
                        for (x = 0; x < 8; x++) {
                                for (y = 0; y < 8; y++) {
                                        output[v][u] += ((double)input[x][y])*Math.cos(((double)(2*x + 1)*(double)u*Math.PI)/(double)16)*Math.cos(((double)(2*y + 1)*(double)v*Math.PI)/(double)16);
                                }
                        }
                        output[v][u] *= (double)(0.25)*((u == 0) ? ((double)1.0/Math.sqrt(2)) : (double) 1.0)*((v == 0) ? ((double)1.0/Math.sqrt(2)) : (double) 1.0);
                }
        }
        return output;
    }
                                                                

    /*
     * This method preforms a DCT on a block of image data using the AAN
     * method as implemented in the IJG Jpeg-6a library.
     */
    public double[][] forwardDCT(float input[][])
    {
        double output[][] = new double[N][N];
        double tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
        double tmp10, tmp11, tmp12, tmp13;
        double z1, z2, z3, z4, z5, z11, z13;
        int i;
        int j;

// Subtracts 128 from the input values
        for (i = 0; i < 8; i++) {
                for(j = 0; j < 8; j++) {
                        output[i][j] = ((double)input[i][j] - (double)128.0);
//                        input[i][j] -= 128;

                }
        }

        for (i = 0; i < 8; i++) {
                tmp0 = output[i][0] + output[i][7];
                tmp7 = output[i][0] - output[i][7];
                tmp1 = output[i][1] + output[i][6];
                tmp6 = output[i][1] - output[i][6];
                tmp2 = output[i][2] + output[i][5];
                tmp5 = output[i][2] - output[i][5];
                tmp3 = output[i][3] + output[i][4];
                tmp4 = output[i][3] - output[i][4];

                tmp10 = tmp0 + tmp3;
                tmp13 = tmp0 - tmp3;
                tmp11 = tmp1 + tmp2;
                tmp12 = tmp1 - tmp2;

                output[i][0] = tmp10 + tmp11;
                output[i][4] = tmp10 - tmp11;

                z1 = (tmp12 + tmp13) * (double) 0.707106781;
                output[i][2] = tmp13 + z1;
                output[i][6] = tmp13 - z1;

                tmp10 = tmp4 + tmp5;
                tmp11 = tmp5 + tmp6;
                tmp12 = tmp6 + tmp7;

                z5 = (tmp10 - tmp12) * (double) 0.382683433;
                z2 = ((double) 0.541196100) * tmp10 + z5;
                z4 = ((double) 1.306562965) * tmp12 + z5;
                z3 = tmp11 * ((double) 0.707106781);

                z11 = tmp7 + z3;
                z13 = tmp7 - z3;

                output[i][5] = z13 + z2;
                output[i][3] = z13 - z2;
                output[i][1] = z11 + z4;
                output[i][7] = z11 - z4;
        }

        for (i = 0; i < 8; i++) {
                tmp0 = output[0][i] + output[7][i];
                tmp7 = output[0][i] - output[7][i];
                tmp1 = output[1][i] + output[6][i];
                tmp6 = output[1][i] - output[6][i];
                tmp2 = output[2][i] + output[5][i];
                tmp5 = output[2][i] - output[5][i];
                tmp3 = output[3][i] + output[4][i];
                tmp4 = output[3][i] - output[4][i];

                tmp10 = tmp0 + tmp3;
                tmp13 = tmp0 - tmp3;
                tmp11 = tmp1 + tmp2;
                tmp12 = tmp1 - tmp2;

                output[0][i] = tmp10 + tmp11;
                output[4][i] = tmp10 - tmp11;

                z1 = (tmp12 + tmp13) * (double) 0.707106781;
                output[2][i] = tmp13 + z1;
                output[6][i] = tmp13 - z1;

                tmp10 = tmp4 + tmp5;
                tmp11 = tmp5 + tmp6;
                tmp12 = tmp6 + tmp7;

                z5 = (tmp10 - tmp12) * (double) 0.382683433;
                z2 = ((double) 0.541196100) * tmp10 + z5;
                z4 = ((double) 1.306562965) * tmp12 + z5;
                z3 = tmp11 * ((double) 0.707106781);

                z11 = tmp7 + z3;
                z13 = tmp7 - z3;

                output[5][i] = z13 + z2;
                output[3][i] = z13 - z2;
                output[1][i] = z11 + z4;
                output[7][i] = z11 - z4;
        }

        return output;
    }

    /*
    * This method quantitizes data and rounds it to the nearest integer.
    */
    public int[] quantizeBlock(double inputData[][], int code)
    {
        int outputData[] = new int[N*N];
        int i, j;
        int index;
        index = 0;
        for (i = 0; i < 8; i++) {
                for (j = 0; j < 8; j++) {
// The second line results in significantly better compression.
                        outputData[index] = (int)(Math.round(inputData[i][j] * (((double[]) (Divisors[code]))[index])));
//                        outputData[index] = (int)(((inputData[i][j] * (((double[]) (Divisors[code]))[index])) + 16384.5) -16384);
                        index++;
                }
        }

        return outputData;
    }

    /*
    * This is the method for quantizing a block DCT'ed with forwardDCTExtreme
    * This method quantitizes data and rounds it to the nearest integer.
    */
    public int[] quantizeBlockExtreme(double inputData[][], int code)
    {
        int outputData[] = new int[N*N];
        int i, j;
        int index;
        index = 0;
        for (i = 0; i < 8; i++) {
                for (j = 0; j < 8; j++) {
                        outputData[index] = (int)(Math.round(inputData[i][j] / (double)(((int[]) (quantum[code]))[index])));
                        index++;
                }
        }

        return outputData;
    }
}

// This class was modified by James R. Weeks on 3/27/98.
// It now incorporates Huffman table derivation as in the C jpeg library
// from the IJG, Jpeg-6a.

class Huffman
{
    int bufferPutBits, bufferPutBuffer;    
    public int ImageHeight;
    public int ImageWidth;
    public int DC_matrix0[][];
    public int AC_matrix0[][];
    public int DC_matrix1[][];
    public int AC_matrix1[][];
    public Object DC_matrix[];
    public Object AC_matrix[];
    public int code;
    public int NumOfDCTables;
    public int NumOfACTables;
    public int[] bitsDCluminance = { 0x00, 0, 1, 5, 1, 1,1,1,1,1,0,0,0,0,0,0,0};
    public int[] valDCluminance = { 0,1,2,3,4,5,6,7,8,9,10,11 };
    public int[] bitsDCchrominance = { 0x01,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0 };
    public int[] valDCchrominance = { 0,1,2,3,4,5,6,7,8,9,10,11 };
    public int[] bitsACluminance = {0x10,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d };
    public int[] valACluminance =
        { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
          0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
          0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
          0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
          0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
          0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
          0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
          0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
          0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
          0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
          0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
          0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
          0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
          0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
          0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
          0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
          0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
          0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
          0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
          0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
          0xf9, 0xfa };
    public int[] bitsACchrominance = { 0x11,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77 };;
    public int[] valACchrominance = 
        { 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
          0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
          0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
          0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
          0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
          0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
          0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38, 
          0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 
          0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 
          0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 
          0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 
          0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 
          0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 
          0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 
          0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 
          0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 
          0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 
          0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 
          0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 
          0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
          0xf9, 0xfa };
    public Vector bits;
    public Vector val;

    /*
     * jpegNaturalOrder[i] is the natural-order position of the i'th element
     * of zigzag order.
     */
    public static int[] jpegNaturalOrder = {
          0,  1,  8, 16,  9,  2,  3, 10,
         17, 24, 32, 25, 18, 11,  4,  5,
         12, 19, 26, 33, 40, 48, 41, 34,
         27, 20, 13,  6,  7, 14, 21, 28,
         35, 42, 49, 56, 57, 50, 43, 36,
         29, 22, 15, 23, 30, 37, 44, 51,
         58, 59, 52, 45, 38, 31, 39, 46,
         53, 60, 61, 54, 47, 55, 62, 63,
        };
    /*
    * The Huffman class constructor
    */
        public Huffman(int Width,int Height)
	{

            bits = new Vector();
            bits.addElement(bitsDCluminance);
            bits.addElement(bitsACluminance);
            bits.addElement(bitsDCchrominance);
            bits.addElement(bitsACchrominance);
            val = new Vector();
            val.addElement(valDCluminance);
            val.addElement(valACluminance);
            val.addElement(valDCchrominance);
            val.addElement(valACchrominance);
            initHuf();
	    code=code;
            ImageWidth=Width;
            ImageHeight=Height;

	}

   /**
   * HuffmanBlockEncoder run length encodes and Huffman encodes the quantized
   * data.
   **/

        public void HuffmanBlockEncoder(BufferedOutputStream outStream, int zigzag[], int prec, int DCcode, int ACcode)
	{
        int temp, temp2, nbits, k, r, i;

        NumOfDCTables = 2;
        NumOfACTables = 2;

// The DC portion

        temp = temp2 = zigzag[0] - prec;
        if(temp < 0) {
                temp = -temp;
                temp2--;
        }
        nbits = 0;
        while (temp != 0) {
                nbits++;
                temp >>= 1;
        }
//        if (nbits > 11) nbits = 11;
        bufferIt(outStream, ((int[][])DC_matrix[DCcode])[nbits][0], ((int[][])DC_matrix[DCcode])[nbits][1]);
        // The arguments in bufferIt are code and size.
        if (nbits != 0) {
                bufferIt(outStream, temp2, nbits);
        }

// The AC portion

        r = 0;

        for (k = 1; k < 64; k++) {
                if ((temp = zigzag[jpegNaturalOrder[k]]) == 0) {
                        r++;
                }
                else {
                        while (r > 15) {
                                bufferIt(outStream, ((int[][])AC_matrix[ACcode])[0xF0][0], ((int[][])AC_matrix[ACcode])[0xF0][1]);
                                r -= 16;
                        }
                        temp2 = temp;
                        if (temp < 0) {
                                temp = -temp;
                                temp2--;
                        }
                        nbits = 1;
                        while ((temp >>= 1) != 0) {
                                nbits++;
                        }
                        i = (r << 4) + nbits;
                        bufferIt(outStream, ((int[][])AC_matrix[ACcode])[i][0], ((int[][])AC_matrix[ACcode])[i][1]);
                        bufferIt(outStream, temp2, nbits);

                        r = 0;
                }
        }

        if (r > 0) {
                bufferIt(outStream, ((int[][])AC_matrix[ACcode])[0][0], ((int[][])AC_matrix[ACcode])[0][1]);
        }

	}

// Uses an integer long (32 bits) buffer to store the Huffman encoded bits
// and sends them to outStream by the byte.

        void bufferIt(BufferedOutputStream outStream, int code,int size)
	{
        int PutBuffer = code;
        int PutBits = bufferPutBits;

        PutBuffer &= (1 << size) - 1;
        PutBits += size;
        PutBuffer <<= 24 - PutBits;
        PutBuffer |= bufferPutBuffer;

        while(PutBits >= 8) {
                int c = ((PutBuffer >> 16) & 0xFF);
                try
                {
                        outStream.write(c);
                }
                catch (IOException e) {
                        System.out.println("IO Error: " + e.getMessage());
                }
                if (c == 0xFF) {
                        try
                        {
                                outStream.write(0);
                        }
                        catch (IOException e) {
                                System.out.println("IO Error: " + e.getMessage());
                        }
                }
                PutBuffer <<= 8;
                PutBits -= 8;
        }
        bufferPutBuffer = PutBuffer;
        bufferPutBits = PutBits;

        }

        void flushBuffer(BufferedOutputStream outStream) {
                int PutBuffer = bufferPutBuffer;
                int PutBits = bufferPutBits;
                while (PutBits >= 8) {
                        int c = ((PutBuffer >> 16) & 0xFF);
                        try
                        {
                                outStream.write(c);
                        }
                        catch (IOException e) {
                                System.out.println("IO Error: " + e.getMessage());
                        }
                        if (c == 0xFF) {
                                try {
                                        outStream.write(0);
                                }
                                catch (IOException e) {
                                        System.out.println("IO Error: " + e.getMessage());
                                }
                        }
                        PutBuffer <<= 8;
                        PutBits -= 8;
                }
                if (PutBits > 0) {
                        int c = ((PutBuffer >> 16) & 0xFF);
                        try
                        {
                                outStream.write(c);
                        }
                        catch (IOException e) {
                                System.out.println("IO Error: " + e.getMessage());
                        }
                }
        }

    /*
    * Initialisation of the Huffman codes for Luminance and Chrominance.
    * This code results in the same tables created in the IJG Jpeg-6a
    * library.
    */

    public void initHuf()
    {
        DC_matrix0=new int[12][2];
        DC_matrix1=new int[12][2];
        AC_matrix0=new int[255][2];
        AC_matrix1=new int[255][2];
        DC_matrix = new Object[2];
        AC_matrix = new Object[2];
        int p, l, i, lastp, si, code;
        int[] huffsize = new int[257];
        int[] huffcode= new int[257];

        /*
        * init of the DC values for the chrominance
        * [][0] is the code   [][1] is the number of bit
        */

        p = 0;
        for (l = 1; l <= 16; l++)
        {
                for (i = 1; i <= bitsDCchrominance[l]; i++)
                {
                        huffsize[p++] = l;
                }
        }
        huffsize[p] = 0;
        lastp = p;

        code = 0;
        si = huffsize[0];
        p = 0;
        while(huffsize[p] != 0)
        {
                while(huffsize[p] == si)
                {
                        huffcode[p++] = code;
                        code++;
                }
                code <<= 1;
                si++;
        }

        for (p = 0; p < lastp; p++)
        {
                DC_matrix1[valDCchrominance[p]][0] = huffcode[p];
                DC_matrix1[valDCchrominance[p]][1] = huffsize[p];
        }

        /*
        * Init of the AC hufmann code for the chrominance
        * matrix [][][0] is the code & matrix[][][1] is the number of bit needed
        */

        p = 0;
        for (l = 1; l <= 16; l++)
        {
                for (i = 1; i <= bitsACchrominance[l]; i++)
                {
                        huffsize[p++] = l;
                }
        }
        huffsize[p] = 0;
        lastp = p;

        code = 0;
        si = huffsize[0];
        p = 0;
        while(huffsize[p] != 0)
        {
                while(huffsize[p] == si)
                {
                        huffcode[p++] = code;
                        code++;
                }
                code <<= 1;
                si++;
        }

        for (p = 0; p < lastp; p++)
        {
                AC_matrix1[valACchrominance[p]][0] = huffcode[p];
                AC_matrix1[valACchrominance[p]][1] = huffsize[p];
        }

        /*
        * init of the DC values for the luminance
        * [][0] is the code   [][1] is the number of bit
        */
        p = 0;
        for (l = 1; l <= 16; l++)
        {
                for (i = 1; i <= bitsDCluminance[l]; i++)
                {
                        huffsize[p++] = l;
                }
        }
        huffsize[p] = 0;
        lastp = p;

        code = 0;
        si = huffsize[0];
        p = 0;
        while(huffsize[p] != 0)
        {
                while(huffsize[p] == si)
                {
                        huffcode[p++] = code;
                        code++;
                }
                code <<= 1;
                si++;
        }

        for (p = 0; p < lastp; p++)
        {
                DC_matrix0[valDCluminance[p]][0] = huffcode[p];
                DC_matrix0[valDCluminance[p]][1] = huffsize[p];
        }

        /*
        * Init of the AC hufmann code for luminance
        * matrix [][][0] is the code & matrix[][][1] is the number of bit
        */

        p = 0;
        for (l = 1; l <= 16; l++)
        {
                for (i = 1; i <= bitsACluminance[l]; i++)
                {
                        huffsize[p++] = l;
                }
        }
        huffsize[p] = 0;
        lastp = p;

        code = 0;
        si = huffsize[0];
        p = 0;
        while(huffsize[p] != 0)
        {
                while(huffsize[p] == si)
                {
                        huffcode[p++] = code;
                        code++;
                }
                code <<= 1;
                si++;
        }
        for (int q = 0; q < lastp; q++)
        {
                AC_matrix0[valACluminance[q]][0] = huffcode[q];
                AC_matrix0[valACluminance[q]][1] = huffsize[q];
        } 

        DC_matrix[0] = DC_matrix0;
        DC_matrix[1] = DC_matrix1;
        AC_matrix[0] = AC_matrix0;
        AC_matrix[1] = AC_matrix1;
    }

}

/*
 * JpegInfo - Given an image, sets default information about it and divides
 * it into its constituant components, downsizing those that need to be.
 */

class JpegInfo
{
    String Comment;
    public Image imageobj;
    public int imageHeight;
    public int imageWidth;
    public int BlockWidth[];
    public int BlockHeight[];

// the following are set as the default
    public int Precision = 8;
    public int NumberOfComponents = 3;
    public Object Components[];
    public int[] CompID = {1, 2, 3};
    //public int[] HsampFactor = {1, 1, 1};
    //public int[] VsampFactor = {1, 1, 1};
    public int[] HsampFactor = {2, 1, 1};
    public int[] VsampFactor = {2, 1, 1};
    public int[] QtableNumber = {0, 1, 1};
    public int[] DCtableNumber = {0, 1, 1};
    public int[] ACtableNumber = {0, 1, 1};
    public boolean[] lastColumnIsDummy = {false, false, false};
    public boolean[] lastRowIsDummy = {false, false, false};
    public int Ss = 0;
    public int Se = 63;
    public int Ah = 0;
    public int Al = 0;
    public int compWidth[], compHeight[];
    public int MaxHsampFactor;
    public int MaxVsampFactor;


    public JpegInfo(Image image, String comment)
    {
        Components = new Object[NumberOfComponents];
        compWidth = new int[NumberOfComponents];
        compHeight = new int[NumberOfComponents];
        BlockWidth = new int[NumberOfComponents];
        BlockHeight = new int[NumberOfComponents];
        imageobj = image;
        imageWidth = image.getWidth(null);
        imageHeight = image.getHeight(null);
        //Comment = "JPEG Encoder Copyright 1998, James R. Weeks and BioElectroMech.  ";
        Comment = comment;
        getYCCArray();
    }

    public void setComment(String comment) {
        Comment.concat(comment);
    }

    public String getComment() {
        return Comment;
    }

    /*
     * This method creates and fills three arrays, Y, Cb, and Cr using the
     * input image.
     */

    private void getYCCArray()
    {
        int values[] = new int[imageWidth * imageHeight];
        int r, g, b, y, x;
// In order to minimize the chance that grabPixels will throw an exception
// it may be necessary to grab some pixels every few scanlines and process
// those before going for more.  The time expense may be prohibitive.
// However, for a situation where memory overhead is a concern, this may be
// the only choice.
    	PixelGrabber grabber = new PixelGrabber(imageobj.getSource(), 0, 0, imageWidth, imageHeight, values, 0, imageWidth);
        MaxHsampFactor = 1;
        MaxVsampFactor = 1;
        for (y = 0; y < NumberOfComponents; y++) {
                MaxHsampFactor = Math.max(MaxHsampFactor, HsampFactor[y]);
                MaxVsampFactor = Math.max(MaxVsampFactor, VsampFactor[y]);
        }
if(false) {
        for (y = 0; y < NumberOfComponents; y++) {
                compWidth[y] = (((imageWidth%8 != 0) ? ((int) Math.ceil((double) imageWidth/8.0))*8 : imageWidth)/MaxHsampFactor)*HsampFactor[y];
                if (compWidth[y] != ((imageWidth/MaxHsampFactor)*HsampFactor[y])) {
                        lastColumnIsDummy[y] = true;
                }
                // results in a multiple of 8 for compWidth
                // this will make the rest of the program fail for the unlikely
                // event that someone tries to compress an 16 x 16 pixel image
                // which would of course be worse than pointless
                BlockWidth[y] = (int) Math.ceil((double) compWidth[y]/8.0);
                compHeight[y] = (((imageHeight%8 != 0) ? ((int) Math.ceil((double) imageHeight/8.0))*8: imageHeight)/MaxVsampFactor)*VsampFactor[y];
                if (compHeight[y] != ((imageHeight/MaxVsampFactor)*VsampFactor[y])) {
                        lastRowIsDummy[y] = true;
                }
                BlockHeight[y] = (int) Math.ceil((double) compHeight[y]/8.0);
        }
} else {
        for (y = 0; y < NumberOfComponents; y++) {
                compWidth[y] = ((
		(imageWidth%8 != 0) ?
		((int) Math.ceil((double) imageWidth/8.0))*8 :
		imageWidth)
		/MaxHsampFactor)*HsampFactor[y];
                if (compWidth[y] != ((imageWidth/MaxHsampFactor)*HsampFactor[y])) {
                        lastColumnIsDummy[y] = true;
                }
                // results in a multiple of 8 for compWidth
                // this will make the rest of the program fail for the unlikely
                // event that someone tries to compress an 16 x 16 pixel image
                // which would of course be worse than pointless
                BlockWidth[y] = (int) Math.ceil((double) compWidth[y]/8.0);
                compHeight[y] = ((
		(imageHeight%8 != 0) ?
		((int) Math.ceil((double) imageHeight/8.0))*8:
		imageHeight)
		/MaxVsampFactor)*VsampFactor[y];
                if (compHeight[y] != ((imageHeight/MaxVsampFactor)*VsampFactor[y])) {
                        lastRowIsDummy[y] = true;
                }
                BlockHeight[y] = (int) Math.ceil((double) compHeight[y]/8.0);
        }
}
        try
    	{
    	    if(grabber.grabPixels() != true)
    	    {
    		    try
    		    {
    		        throw new AWTException("Grabber returned false: " + grabber.getStatus());
    		    }
    		    catch (Exception e) {};
            }
    	}
    	catch (InterruptedException e) {};
        float Y[][] = new float[compHeight[0]][compWidth[0]];
        float Cr1[][] = new float[compHeight[0]][compWidth[0]];
        float Cb1[][] = new float[compHeight[0]][compWidth[0]];
        float Cb2[][] = new float[compHeight[1]][compWidth[1]];
        float Cr2[][] = new float[compHeight[2]][compWidth[2]];
        int index = 0;
        for (y = 0; y < imageHeight; ++y)
    	{
            for (x = 0; x < imageWidth; ++x)
    	    {
                r = ((values[index] >> 16) & 0xff);
                g = ((values[index] >> 8) & 0xff);
                b = (values[index] & 0xff);

// The following three lines are a more correct color conversion but
// the current conversion technique is sufficient and results in a higher
// compression rate.
//                Y[y][x] = 16 + (float)(0.8588*(0.299 * (float)r + 0.587 * (float)g + 0.114 * (float)b ));
//                Cb1[y][x] = 128 + (float)(0.8784*(-0.16874 * (float)r - 0.33126 * (float)g + 0.5 * (float)b));
//                Cr1[y][x] = 128 + (float)(0.8784*(0.5 * (float)r - 0.41869 * (float)g - 0.08131 * (float)b));
                Y[y][x] = (float)((0.299 * (float)r + 0.587 * (float)g + 0.114 * (float)b));
                Cb1[y][x] = 128 + (float)((-0.16874 * (float)r - 0.33126 * (float)g + 0.5 * (float)b));
                Cr1[y][x] = 128 + (float)((0.5 * (float)r - 0.41869 * (float)g - 0.08131 * (float)b));
                index++;
    	    }
    	}

// Need a way to set the H and V sample factors before allowing downsampling.
// For now (04/04/98) downsampling must be hard coded.
// Until a better downsampler is implemented, this will not be done.
// Downsampling is currently supported.  The downsampling method here
// is a simple box filter.

        Components[0] = Y;
	if (false) {
	//        Cb2 = DownSample(Cb1, 1);
		Components[1] = Cb1;
	//        Cr2 = DownSample(Cr1, 2);
		Components[2] = Cr1;
	} else {
	        Cb2 = DownSample(Cb1, 1);
		Components[1] = Cb2;
	        Cr2 = DownSample(Cr1, 2);
		Components[2] = Cr2;
	}
    }

    float[][] DownSample(float[][] C, int comp)
    {
        int inrow, incol;
        int outrow, outcol;
        float output[][];
        float temp;
        int bias;
        inrow = 0;
        incol = 0;
        output = new float[compHeight[comp]][compWidth[comp]];
        for (outrow = 0; outrow < compHeight[comp]; outrow++) {
                bias = 1;
                for (outcol = 0; outcol < compWidth[comp]; outcol++) {
//System.out.println("outcol="+outcol);
			temp = C[inrow][incol++];	// 00
			temp += C[inrow++][incol--];	// 01
			temp += C[inrow][incol++];	// 10
			temp += C[inrow--][incol++] + (float)bias; // 11 -> 02
                        output[outrow][outcol] = temp/(float)4.0;
                        bias ^= 3;
                }
                inrow += 2;
                incol = 0;
        }
        return output;
    }
}