| /* |
| * Copyright (c) 2005, 2016, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package com.sun.imageio.plugins.tiff; |
| |
| import java.io.IOException; |
| import javax.imageio.IIOException; |
| |
| class TIFFLZWUtil { |
| public TIFFLZWUtil() { |
| } |
| |
| byte[] srcData; |
| int srcIndex; |
| |
| byte[] dstData; |
| int dstIndex = 0; |
| |
| byte stringTable[][]; |
| int tableIndex, bitsToGet = 9; |
| |
| int nextData = 0; |
| int nextBits = 0; |
| |
| private static final int andTable[] = { |
| 511, |
| 1023, |
| 2047, |
| 4095 |
| }; |
| |
| public byte[] decode(byte[] data, int predictor, int samplesPerPixel, |
| int width, int height) throws IOException { |
| if (data[0] == (byte)0x00 && data[1] == (byte)0x01) { |
| throw new IIOException("TIFF 5.0-style LZW compression is not supported!"); |
| } |
| |
| this.srcData = data; |
| this.srcIndex = 0; |
| this.nextData = 0; |
| this.nextBits = 0; |
| |
| this.dstData = new byte[8192]; |
| this.dstIndex = 0; |
| |
| initializeStringTable(); |
| |
| int code, oldCode = 0; |
| byte[] string; |
| |
| while ((code = getNextCode()) != 257) { |
| if (code == 256) { |
| initializeStringTable(); |
| code = getNextCode(); |
| 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 == 2) { |
| |
| int count; |
| for (int j = 0; j < height; j++) { |
| |
| count = samplesPerPixel * (j * width + 1); |
| |
| for (int i = samplesPerPixel; i < width * samplesPerPixel; i++) { |
| |
| dstData[count] += dstData[count - samplesPerPixel]; |
| count++; |
| } |
| } |
| } |
| |
| byte[] newDstData = new byte[dstIndex]; |
| System.arraycopy(dstData, 0, newDstData, 0, dstIndex); |
| return newDstData; |
| } |
| |
| /** |
| * 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; |
| } |
| |
| private void ensureCapacity(int bytesToAdd) { |
| if (dstIndex + bytesToAdd > dstData.length) { |
| byte[] newDstData = new byte[Math.max((int)(dstData.length*1.2f), |
| dstIndex + bytesToAdd)]; |
| System.arraycopy(dstData, 0, newDstData, 0, dstData.length); |
| dstData = newDstData; |
| } |
| } |
| |
| /** |
| * Write out the string just uncompressed. |
| */ |
| public void writeString(byte string[]) { |
| ensureCapacity(string.length); |
| for (int i = 0; i < string.length; 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} to the end of {@code oldString}. |
| */ |
| 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; |
| } |
| |
| // 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 { |
| nextData = (nextData << 8) | (srcData[srcIndex++] & 0xff); |
| nextBits += 8; |
| |
| if (nextBits < bitsToGet) { |
| nextData = (nextData << 8) | (srcData[srcIndex++] & 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; |
| } |
| } |
| } |