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ImageIO plugin for Aldus/Adobe Tagged Image File Format (TIFF).
/*
* Copyright (c) 2012, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions 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 the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.twelvemonkeys.imageio.plugins.tiff;
import com.twelvemonkeys.io.enc.DecodeException;
import com.twelvemonkeys.io.enc.Decoder;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
/**
* Lempel–Ziv–Welch (LZW) decompression.
* LZW is a universal loss-less data compression algorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch.
* Inspired by libTiff's LZW decompression.
*
* @author Harald Kuhr
* @author last modified by $Author: haraldk$
* @version $Id: LZWDecoder.java,v 1.0 08.05.12 21:11 haraldk Exp$
* @see LZW (Wikipedia)
*/
abstract class LZWDecoder implements Decoder {
/** Clear: Re-initialize tables. */
static final int CLEAR_CODE = 256;
/** End of Information. */
static final int EOI_CODE = 257;
private static final int MIN_BITS = 9;
private static final int MAX_BITS = 12;
private static final int TABLE_SIZE = 1 << MAX_BITS;
private final LZWString[] table;
private int tableLength;
int bitsPerCode;
private int oldCode = CLEAR_CODE;
private int maxCode;
int bitMask;
private int maxString;
boolean eofReached;
int nextData;
int nextBits;
protected LZWDecoder(int tableSize) {
table = new LZWString[tableSize];
// First 258 entries of table is always fixed
for (int i = 0; i < 256; i++) {
table[i] = new LZWString((byte) i);
}
init();
}
private static int bitmaskFor(final int bits) {
return (1 << bits) - 1;
}
private void init() {
tableLength = 258;
bitsPerCode = MIN_BITS;
bitMask = bitmaskFor(bitsPerCode);
maxCode = maxCode();
maxString = 1;
}
public int decode(final InputStream stream, final ByteBuffer buffer) throws IOException {
if (buffer == null) {
throw new NullPointerException("buffer == null"); // As per contract
}
// Adapted from the pseudo-code example found in the TIFF 6.0 Specification, 1992.
// See Section 13: "LZW Compression"/"LZW Decoding", page 61+
int code;
while ((code = getNextCode(stream)) != EOI_CODE) {
if (code == CLEAR_CODE) {
init();
code = getNextCode(stream);
if (code == EOI_CODE) {
break;
}
if (table[code] == null) {
throw new DecodeException(String.format("Corrupted TIFF LZW: code %d (table size: %d)", code, tableLength));
}
table[code].writeTo(buffer);
}
else {
if (table[oldCode] == null) {
throw new DecodeException(String.format("Corrupted TIFF LZW: code %d (table size: %d)", oldCode, tableLength));
}
if (isInTable(code)) {
table[code].writeTo(buffer);
addStringToTable(table[oldCode].concatenate(table[code].firstChar));
}
else {
LZWString outString = table[oldCode].concatenate(table[oldCode].firstChar);
outString.writeTo(buffer);
addStringToTable(outString);
}
}
oldCode = code;
if (buffer.remaining() < maxString + 1) {
// Buffer (almost) full, stop decoding for now
break;
}
}
return buffer.position();
}
private void addStringToTable(final LZWString string) throws IOException {
if (tableLength > table.length) {
throw new DecodeException(String.format("TIFF LZW with more than %d bits per code encountered (table overflow)", MAX_BITS));
}
table[tableLength++] = string;
if (tableLength > maxCode) {
bitsPerCode++;
if (bitsPerCode > MAX_BITS) {
// Continue reading MAX_BITS (12 bit) length codes
bitsPerCode = MAX_BITS;
}
bitMask = bitmaskFor(bitsPerCode);
maxCode = maxCode();
}
if (string.length > maxString) {
maxString = string.length;
}
}
protected abstract int maxCode();
private boolean isInTable(int code) {
return code < tableLength;
}
protected abstract int getNextCode(final InputStream stream) throws IOException;
static boolean isOldBitReversedStream(final InputStream stream) throws IOException {
stream.mark(2);
try {
int one = stream.read();
int two = stream.read();
return one == 0 && (two & 0x1) == 1; // => (reversed) 1 00000000 == 256 (CLEAR_CODE)
}
finally {
stream.reset();
}
}
public static Decoder create(boolean oldBitReversedStream) {
return oldBitReversedStream ? new LZWCompatibilityDecoder() : new LZWSpecDecoder();
}
static final class LZWSpecDecoder extends LZWDecoder {
protected LZWSpecDecoder() {
super(TABLE_SIZE);
}
@Override
protected int maxCode() {
return bitMask - 1;
}
protected final int getNextCode(final InputStream stream) throws IOException {
if (eofReached) {
return EOI_CODE;
}
int code;
int read = stream.read();
if (read < 0) {
eofReached = true;
return EOI_CODE;
}
nextData = (nextData << 8) | read;
nextBits += 8;
if (nextBits < bitsPerCode) {
read = stream.read();
if (read < 0) {
eofReached = true;
return EOI_CODE;
}
nextData = (nextData << 8) | read;
nextBits += 8;
}
code = ((nextData >> (nextBits - bitsPerCode)) & bitMask);
nextBits -= bitsPerCode;
return code;
}
}
private static final class LZWCompatibilityDecoder extends LZWDecoder {
// NOTE: This is a spec violation. However, libTiff reads such files.
// TIFF 6.0 Specification, Section 13: "LZW Compression"/"The Algorithm", page 61, says:
// "LZW compression codes are stored into bytes in high-to-low-order fashion, i.e., FillOrder
// is assumed to be 1. The compressed codes are written as bytes (not words) so that the
// compressed data will be identical whether it is an ‘II’ or ‘MM’ file."
protected LZWCompatibilityDecoder() {
super(TABLE_SIZE + 1024); // libTiff adds 1024 "for compatibility", this value seems to work fine...
}
@Override
protected int maxCode() {
return bitMask;
}
protected final int getNextCode(final InputStream stream) throws IOException {
if (eofReached) {
return EOI_CODE;
}
int code;
int read = stream.read();
if (read < 0) {
eofReached = true;
return EOI_CODE;
}
nextData |= read << nextBits;
nextBits += 8;
if (nextBits < bitsPerCode) {
read = stream.read();
if (read < 0) {
eofReached = true;
return EOI_CODE;
}
nextData |= read << nextBits;
nextBits += 8;
}
code = (nextData & bitMask);
nextData >>= bitsPerCode;
nextBits -= bitsPerCode;
return code;
}
}
static final class LZWString implements Comparable {
static final LZWString EMPTY = new LZWString((byte) 0, (byte) 0, 0, null);
final LZWString previous;
final int length;
final byte value;
final byte firstChar; // Copied forward for fast access
public LZWString(final byte code) {
this(code, code, 1, null);
}
private LZWString(final byte value, final byte firstChar, final int length, final LZWString previous) {
this.value = value;
this.firstChar = firstChar;
this.length = length;
this.previous = previous;
}
public final LZWString concatenate(final byte value) {
if (this == EMPTY) {
return new LZWString(value);
}
return new LZWString(value, this.firstChar, length + 1, this);
}
public final void writeTo(final ByteBuffer buffer) {
if (length == 0) {
return;
}
if (length == 1) {
buffer.put(value);
}
else {
LZWString e = this;
final int offset = buffer.position();
for (int i = length - 1; i >= 0; i--) {
buffer.put(offset + i, e.value);
e = e.previous;
}
buffer.position(offset + length);
}
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder("ZLWString[");
int offset = builder.length();
LZWString e = this;
for (int i = length - 1; i >= 0; i--) {
builder.insert(offset, String.format("%2x", e.value));
e = e.previous;
}
builder.append("]");
return builder.toString();
}
@Override
public boolean equals(final Object other) {
if (this == other) {
return true;
}
if (other == null || getClass() != other.getClass()) {
return false;
}
LZWString string = (LZWString) other;
return firstChar == string.firstChar &&
length == string.length &&
value == string.value &&
// !(previous != null ? !previous.equals(string.previous) : string.previous != null);
previous == string.previous;
}
@Override
public int hashCode() {
int result = previous != null ? previous.hashCode() : 0;
result = 31 * result + length;
result = 31 * result + (int) value;
result = 31 * result + (int) firstChar;
return result;
}
@Override
public int compareTo(final LZWString other) {
if (other == this) {
return 0;
}
if (length != other.length) {
return other.length - length;
}
if (firstChar != other.firstChar) {
return other.firstChar - firstChar;
}
LZWString t = this;
LZWString o = other;
for (int i = length - 1; i > 0; i--) {
if (t.value != o.value) {
return o.value - t.value;
}
t = t.previous;
o = o.previous;
}
return 0;
}
}
}
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