org.jpedal.io.filter.TiffLZWBuffer Maven / Gradle / Ivy
/*
* ===========================================
* Java Pdf Extraction Decoding Access Library
* ===========================================
*
* Project Info: http://www.idrsolutions.com
* Help section for developers at http://www.idrsolutions.com/support/
*
* (C) Copyright 1997-2017 IDRsolutions and Contributors.
*
* This file is part of JPedal/JPDF2HTML5
*
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* ---------------
* TiffLZWBuffer.java
* ---------------
*/
package org.jpedal.io.filter;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.IOException;
public class TiffLZWBuffer {
private byte[][] codes;
private BufferedOutputStream output;
private BufferedInputStream input;
private int bitsToGet = 9;
private int tp;
private int putBuffer, putBits;
public void decompress(final BufferedOutputStream output, final BufferedInputStream input) throws IOException {
init();
this.input = input;
this.output = output;
putBuffer = 0;
putBits = 0;
int code, oldCode = 0;
byte[] chars;
while (((code = findNext()) != 257)) {
if (code == 256) {
init();
code = findNext();
if (code == 257) {
break;
}
addCodes(codes[code]);
oldCode = code;
} else {
if (code < tp) {
chars = codes[code];
addCodes(chars);
addCodeToCodes(codes[oldCode], chars[0]);
oldCode = code;
} else {
chars = codes[oldCode];
chars = generateCodeArray(chars, chars[0]);
addCodes(chars);
addCodeArrToCodes(chars);
oldCode = code;
}
}
}
}
public void init() {
codes = new byte[4096][];
for (int i = 0; i < 256; i++) {
codes[i] = new byte[1];
codes[i][0] = (byte) i;
}
tp = 258;
bitsToGet = 9;
}
private void addCodes(final byte[] codes) throws IOException {
output.write(codes);
}
private void addCodeToCodes(final byte[] oldCodes, final byte code) {
final int length = oldCodes.length;
final byte[] string = new byte[length + 1];
System.arraycopy(oldCodes, 0, string, 0, length);
string[length] = code;
codes[tp++] = string;
if (tp == 511) {
bitsToGet = 10;
} else if (tp == 1023) {
bitsToGet = 11;
} else if (tp == 2047) {
bitsToGet = 12;
}
}
private void addCodeArrToCodes(final byte[] codeArr) {
codes[tp++] = codeArr;
if (tp == 511) {
bitsToGet = 10;
} else if (tp == 1023) {
bitsToGet = 11;
} else if (tp == 2047) {
bitsToGet = 12;
}
}
private static byte[] generateCodeArray(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;
}
private int findNext() {
final int[] combinator = {511, 1023, 2047, 4095};
try {
putBuffer = (putBuffer << 8) | input.read();
putBits += 8;
if (putBits < bitsToGet) {
putBuffer = (putBuffer << 8) | input.read();
putBits += 8;
}
final int code = (putBuffer >> (putBits - bitsToGet)) & combinator[bitsToGet - 9];
putBits -= bitsToGet;
return code;
} catch (final Exception e) {
System.err.println("Exception in findNext " + e);
return 257;
}
}
}