/*
 * $RCSfile: TIFFLZWDecompressor.java,v $
 *
 * 
 * Copyright (c) 2005 Sun Microsystems, Inc. All  Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met: 
 * 
 * - Redistribution of source code must retain the above copyright 
 *   notice, this  list of conditions and the following disclaimer.
 * 
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in 
 *   the documentation and/or other materials provided with the
 *   distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of 
 * contributors may be used to endorse or promote products derived 
 * from this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any 
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND 
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
 * EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL 
 * NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF 
 * USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR 
 * ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
 * CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
 * REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
 * INABILITY TO USE THIS SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES. 
 * 
 * You acknowledge that this software is not designed or intended for 
 * use in the design, construction, operation or maintenance of any 
 * nuclear facility. 
 *
 * $Revision: 1.1 $
 * $Date: 2005/02/11 05:01:48 $
 * $State: Exp $
 */
package com.github.jaiimageio.impl.plugins.tiff;

import java.io.IOException;
import java.nio.ByteOrder;

import javax.imageio.IIOException;

import com.github.jaiimageio.plugins.tiff.BaselineTIFFTagSet;
import com.github.jaiimageio.plugins.tiff.TIFFDecompressor;
import com.github.jaiimageio.plugins.tiff.TIFFField;

public class TIFFLZWDecompressor extends TIFFDecompressor {

    private static final boolean DEBUG = false;
    private static final boolean TRACE = false;

    private static final int andTable[] = {
        511, 
        1023,
        2047,
        4095
    };

    int predictor;

    byte[] srcData;
    byte[] dstData;

    int srcIndex;
    int dstIndex;

    byte stringTable[][];
    int tableIndex, bitsToGet = 9;

    int nextData = 0;
    int nextBits = 0;
    
    boolean isLSB = false;

    public TIFFLZWDecompressor(int predictor) throws IIOException {
        super();

        if (predictor != BaselineTIFFTagSet.PREDICTOR_NONE && 
            predictor != 
            BaselineTIFFTagSet.PREDICTOR_HORIZONTAL_DIFFERENCING) {
            throw new IIOException("Illegal value for Predictor in " +
                                   "TIFF file");
        }

        if(DEBUG) {
            System.out.println("Using horizontal differencing predictor");
        }

        this.predictor = predictor;
    }

    public void decodeRaw(byte[] b,
                          int dstOffset,
                          int bitsPerPixel,
                          int scanlineStride) throws IOException {

        // Check bitsPerSample.
        if (predictor == 
            BaselineTIFFTagSet.PREDICTOR_HORIZONTAL_DIFFERENCING) {
            int len = bitsPerSample.length;
            for(int i = 0; i < len; i++) {
                if(bitsPerSample[i] != 8) {
                    throw new IIOException
                        (bitsPerSample[i] + "-bit samples "+
                         "are not supported for Horizontal "+
                         "differencing Predictor");
                }
            }
        }

        stream.seek(offset);

        byte[] sdata = new byte[byteCount];
        stream.readFully(sdata);

        int bytesPerRow = (srcWidth*bitsPerPixel + 7)/8;
        byte[] buf;
        int bufOffset;
        if(bytesPerRow == scanlineStride) {
            buf = b;
            bufOffset = dstOffset;
        } else {
            buf = new byte[bytesPerRow*srcHeight];
            bufOffset = 0;
        }

        int numBytesDecoded = decode(sdata, 0, buf, bufOffset);

        if(bytesPerRow != scanlineStride) {
            if(DEBUG) {
                System.out.println("bytesPerRow != scanlineStride");
            }
            int off = 0;
            for (int y = 0; y < srcHeight; y++) {
                System.arraycopy(buf, off, b, dstOffset, bytesPerRow);
                off += bytesPerRow;
                dstOffset += scanlineStride;
            }
        }
    }
    
    public int decode(byte[] sdata, int srcOffset,
                byte[] ddata, int dstOffset)
                                throws IOException {
        if (sdata[0] == (byte)0x00 && sdata[1] == (byte)0x01) {
                throw new IIOException
                ("TIFF 5.0-style LZW compression is not supported!");
        }

        this.srcData = sdata;
        this.dstData = ddata;

        this.srcIndex = srcOffset;
        this.dstIndex = dstOffset;

        this.nextData = 0;
        this.nextBits = 0;

        isLSB = false ;
        if(null != reader ) {
                if( reader instanceof TIFFImageReader) {
                        isLSB = ((TIFFImageReader)reader).isLsb();
                }
        }
        initializeStringTable();

        int code, oldCode = 0;
        byte[] string;
        if(TRACE) {
                System.out.println("start: ");
        }
        while ((code = getNextCode()) != 257) {
                if(TRACE) {
                        System.out.println("Code: "+code);
                }
                if (code == 256) {
                        if(TRACE) {
                                System.out.println("reset");
                        }
                        initializeStringTable();
                        code = getNextCode();
                        if(TRACE) {
                                System.out.println("Code2: "+code);
                        }
                        if (code == 257) {
                                break;
                        }

                        writeString(stringTable[code]);
                        oldCode = code;
                } else {
                        if (code < tableIndex) {
                                string = stringTable[code];

                                writeString(string);
                                addStringToTable(stringTable[oldCode], string[0]); 
                                oldCode = code;
                        } else {
                                string = stringTable[oldCode];
                                string = composeString(string, string[0]);
                                writeString(string);
                                addStringToTable(string);
                                oldCode = code;
                        }
                }
        }

        if (predictor ==
                        BaselineTIFFTagSet.PREDICTOR_HORIZONTAL_DIFFERENCING) {

                for (int j = 0; j < srcHeight; j++) {

                        int count = dstOffset + samplesPerPixel * (j * srcWidth + 1);

                        for (int i = samplesPerPixel; i < srcWidth * samplesPerPixel; i++) {

                                dstData[count] += dstData[count - samplesPerPixel];
                                count++;
                        }
                }
        }

        return dstIndex - dstOffset;
    }

    /**
     * Initialize the string table.
     */
    public void initializeStringTable() {
        stringTable = new byte[4096][];
        
        for (int i = 0; i < 256; i++) {
            stringTable[i] = new byte[1];
            stringTable[i][0] = (byte)i;
        }
        
        tableIndex = 258;
        bitsToGet = 9;
        
    }

    /**
     * Write out the string just uncompressed.
     */
    public void writeString(byte string[]) {
        if(dstIndex < dstData.length) {
            int maxIndex = Math.min(string.length,
                                    dstData.length - dstIndex);

            for (int i=0; i < maxIndex; i++) {
                dstData[dstIndex++] = string[i];
            }
        }
    }
    
    /**
     * Add a new string to the string table.
     */
    public void addStringToTable(byte oldString[], byte newString) {
        int length = oldString.length;
        byte string[] = new byte[length + 1];
        System.arraycopy(oldString, 0, string, 0, length);
        string[length] = newString;
        
        // Add this new String to the table
        stringTable[tableIndex++] = string;
        
        if (tableIndex == 511) {
            bitsToGet = 10;
        } else if (tableIndex == 1023) {
            bitsToGet = 11;
        } else if (tableIndex == 2047) {
            bitsToGet = 12;
        } 
    }

    /**
     * Add a new string to the string table.
     */
    public void addStringToTable(byte string[]) {
        // Add this new String to the table
        stringTable[tableIndex++] = string;
        
        if (tableIndex == 511) {
            bitsToGet = 10;
        } else if (tableIndex == 1023) {
            bitsToGet = 11;
        } else if (tableIndex == 2047) {
            bitsToGet = 12;
        } 
    }

    /**
     * Append <code>newString</code> to the end of <code>oldString</code>.
     */
    public byte[] composeString(byte oldString[], byte newString) {
        int length = oldString.length;
        byte string[] = new byte[length + 1];
        System.arraycopy(oldString, 0, string, 0, length);
        string[length] = newString;

        return string;
    }
    
    public int reverseBits(int inp)
    {
        return TIFFFillOrder.reverseTable[inp] ; 
    }

    // This code to build the fillOrder table
    public static void generateBitsreverseBits()
    {
        for( int iOuter = 0 ; iOuter < 256 ; iOuter ++ ) {
                        int iz = 0 ;
                        int po2 = 1;
                        int rev = 0x80;
                        for( int i = 0 ; i < 8 ; i++) {
                                if( (iOuter & po2 ) != 0 ) {
                                        iz += rev;
                                }
                                po2 <<= 1 ;
                                rev >>= 1;
                        }
                        byte b = (byte)iz ;
                        String value = String.format("0x%02X,", b & 0x00FF);
                        System.out.println(value+" //"+ iOuter+" "
                                        +String.format("%8s", Integer.toBinaryString(iOuter)).replace(" ", "0")
                                        +" -> "
                                        +String.format("%8s", Integer.toBinaryString(iz)).replace(" ", "0"));
        }
        }

    // Returns the next 9, 10, 11 or 12 bits
    public int getNextCode() {
        // Attempt to get the next code. The exception is caught to make
        // this robust to cases wherein the EndOfInformation code has been
        // omitted from a strip. Examples of such cases have been observed
        // in practice.

        try {
                if(!isLSB) {
                        int iz = srcData[srcIndex++] &0x00FF;
                    nextData = (nextData << 8) | (iz& 0xff);
                    nextBits += 8;
        
                    if (nextBits < bitsToGet) {
                        iz = srcData[srcIndex++] &0x00FF;
                        nextData = (nextData << 8) | (iz & 0xff);
                        nextBits += 8;
                    }
        
                    int code =
                        (nextData >> (nextBits - bitsToGet)) & andTable[bitsToGet - 9];
                    nextBits -= bitsToGet;
        
                    return code;                        
                } else {
                        int iz = reverseBits( srcData[srcIndex++] &0x00FF);
                    nextData = (nextData << 8) | (iz& 0xff);
                    nextBits += 8;
        
                    if (nextBits < bitsToGet) {
                        iz = reverseBits( srcData[srcIndex++] &0x00FF);
                        nextData = (nextData << 8) | (iz & 0xff);
                        nextBits += 8;
                    }
        
                    int code =
                        (nextData >> (nextBits - bitsToGet)) & andTable[bitsToGet - 9];
                    nextBits -= bitsToGet;
        
                    return code;
                }
        } catch (ArrayIndexOutOfBoundsException e) {
            // Strip not terminated as expected: return EndOfInformation code.
            return 257;
        }
    }
    
}