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com.aowagie.text.pdf.codec.TIFFLZWDecoder Maven / Gradle / Ivy

/*
 * Copyright 2003-2008 by Paulo Soares.
 *
 * This code was originally released in 2001 by SUN (see class
 * com.sun.media.imageioimpl.plugins.tiff.TIFFLZWDecompressor.java)
 * using the BSD license in a specific wording. In a mail dating from
 * January 23, 2008, Brian Burkhalter (@sun.com) gave us permission
 * to use the code under the following version of the BSD license:
 *
 * 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.
 */
package com.aowagie.text.pdf.codec;

/**
 * A class for performing LZW decoding.
 *
 *
 */
class TIFFLZWDecoder {

    private byte stringTable[][];
    private byte data[] = null, uncompData[];
    private int tableIndex, bitsToGet = 9;
    private int bytePointer, bitPointer;
    private int dstIndex;
    private final int w;
	private int h;
    private final int predictor, samplesPerPixel;
    private int nextData = 0;
    private int nextBits = 0;

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

    TIFFLZWDecoder(final int w, final int predictor, final int samplesPerPixel) {
        this.w = w;
        this.predictor = predictor;
        this.samplesPerPixel = samplesPerPixel;
    }

    /**
     * Method to decode LZW compressed data.
     *
     * @param data            The compressed data.
     * @param uncompData      Array to return the uncompressed data in.
     * @param h               The number of rows the compressed data contains.
     */
    byte[] decode(final byte data[], final byte uncompData[], final int h) {

        if(data[0] == (byte)0x00 && data[1] == (byte)0x01) {
            throw new UnsupportedOperationException("TIFF 5.0-style LZW codes are not supported.");
        }

        initializeStringTable();

        this.data = data;
        this.h = h;
        this.uncompData = uncompData;

        // Initialize pointers
        this.bytePointer = 0;
        this.bitPointer = 0;
        this.dstIndex = 0;


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

        int code, oldCode = 0;
        byte string[];

        while ( (code = getNextCode()) != 257 &&
        this.dstIndex < uncompData.length) {

            if (code == 256) {

                initializeStringTable();
                code = getNextCode();

                if (code == 257) {
                    break;
                }

                writeString(this.stringTable[code]);
                oldCode = code;

            } else {

                if (code < this.tableIndex) {

                    string = this.stringTable[code];

                    writeString(string);
                    addStringToTable(this.stringTable[oldCode], string[0]);
                    oldCode = code;

                } else {

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

            }

        }

        // Horizontal Differencing Predictor
        if (this.predictor == 2) {

            int count;
            for (int j = 0; j < h; j++) {

                count = this.samplesPerPixel * (j * this.w + 1);

                for (int i = this.samplesPerPixel; i < this.w * this.samplesPerPixel; i++) {

                    uncompData[count] += uncompData[count - this.samplesPerPixel];
                    count++;
                }
            }
        }

        return uncompData;
    }


    /**
     * Initialize the string table.
     */
    private void initializeStringTable() {

        this.stringTable = new byte[4096][];

        for (int i=0; i<256; i++) {
            this.stringTable[i] = new byte[1];
            this.stringTable[i][0] = (byte)i;
        }

        this.tableIndex = 258;
        this.bitsToGet = 9;
    }

    /**
     * Write out the string just uncompressed.
     */
    private void writeString(final byte string[]) {
        // Fix for broken tiff files
        int max = this.uncompData.length - this.dstIndex;
        if (string.length < max) {
			max = string.length;
		}
        System.arraycopy(string, 0, this.uncompData, this.dstIndex, max);
        this.dstIndex += max;
    }

    /**
     * Add a new string to the string table.
     */
    private void addStringToTable(final byte oldString[], final byte newString) {
        final int length = oldString.length;
        final byte string[] = new byte[length + 1];
        System.arraycopy(oldString, 0, string, 0, length);
        string[length] = newString;

        // Add this new String to the table
        this.stringTable[this.tableIndex++] = string;

        if (this.tableIndex == 511) {
            this.bitsToGet = 10;
        } else if (this.tableIndex == 1023) {
            this.bitsToGet = 11;
        } else if (this.tableIndex == 2047) {
            this.bitsToGet = 12;
        }
    }

    /**
     * Add a new string to the string table.
     */
    private void addStringToTable(final byte string[]) {

        // Add this new String to the table
        this.stringTable[this.tableIndex++] = string;

        if (this.tableIndex == 511) {
            this.bitsToGet = 10;
        } else if (this.tableIndex == 1023) {
            this.bitsToGet = 11;
        } else if (this.tableIndex == 2047) {
            this.bitsToGet = 12;
        }
    }

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

        return string;
    }

    // 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 {
            this.nextData = this.nextData << 8 | this.data[this.bytePointer++] & 0xff;
            this.nextBits += 8;

            if (this.nextBits < this.bitsToGet) {
                this.nextData = this.nextData << 8 | this.data[this.bytePointer++] & 0xff;
                this.nextBits += 8;
            }

            final int code =
            this.nextData >> this.nextBits - this.bitsToGet & this.andTable[this.bitsToGet-9];
            this.nextBits -= this.bitsToGet;

            return code;
        } catch(final ArrayIndexOutOfBoundsException e) {
            // Strip not terminated as expected: return EndOfInformation code.
            return 257;
        }
    }
}




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