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ImageIO plugin for Adobe Photoshop Document (PSD).
/*
* Copyright (c) 2013, 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.psd;
import com.twelvemonkeys.lang.Validate;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
/**
* A decoder for data converted using "horizontal differencing predictor".
*
* @author Harald Kuhr
* @author last modified by $Author: haraldk$
* @version $Id: HorizontalDeDifferencingStream.java,v 1.0 11.03.13 14:20 haraldk Exp$
*/
final class HorizontalDeDifferencingStream extends InputStream {
/// TODO: Create shared version with TIFF, or see if we can avoid some duplication?
// See TIFF 6.0 Specification, Section 14: "Differencing Predictor", page 64.
private final int columns;
// NOTE: PlanarConfiguration == 2 may be treated as samplesPerPixel == 1
private final int samplesPerPixel;
private final int bitsPerSample;
private final ReadableByteChannel channel;
private final ByteBuffer buffer;
public HorizontalDeDifferencingStream(final InputStream stream, final int columns, final int samplesPerPixel, final int bitsPerSample, final ByteOrder byteOrder) {
this.columns = Validate.isTrue(columns > 0, columns, "width must be greater than 0");
this.samplesPerPixel = Validate.isTrue(bitsPerSample >= 8 || samplesPerPixel == 1, samplesPerPixel, "Unsupported samples per pixel for < 8 bit samples: %s");
this.bitsPerSample = Validate.isTrue(isValidBPS(bitsPerSample), bitsPerSample, "Unsupported bits per sample value: %s");
channel = Channels.newChannel(Validate.notNull(stream, "stream"));
buffer = ByteBuffer.allocate((columns * samplesPerPixel * bitsPerSample + 7) / 8).order(byteOrder);
buffer.flip();
}
static boolean isValidBPS(final int bitsPerSample) {
switch (bitsPerSample) {
case 1:
case 2:
case 4:
case 8:
case 16:
case 32:
case 64:
return true;
default:
return false;
}
}
@SuppressWarnings("StatementWithEmptyBody")
private boolean fetch() throws IOException {
buffer.clear();
// This *SHOULD* read an entire row of pixels (or nothing at all) into the buffer,
// otherwise we will throw EOFException below
while (channel.read(buffer) > 0);
if (buffer.position() > 0) {
if (buffer.hasRemaining()) {
throw new EOFException("Unexpected end of stream");
}
decodeRow();
buffer.flip();
return true;
}
else {
buffer.position(buffer.capacity());
return false;
}
}
private void decodeRow() {
// Un-apply horizontal predictor
byte original;
int sample = 0;
byte temp;
// Optimization:
// Access array directly for <= 8 bits per sample, as buffer does extra index bounds check for every
// put/get operation... (Measures to about 100 ms difference for 4000 x 3000 image)
final byte[] array = buffer.array();
switch (bitsPerSample) {
case 1:
for (int b = 0; b < (columns + 7) / 8; b++) {
original = array[b];
sample += (original >> 7) & 0x1;
temp = (byte) ((sample << 7) & 0x80);
sample += (original >> 6) & 0x1;
temp |= (byte) ((sample << 6) & 0x40);
sample += (original >> 5) & 0x1;
temp |= (byte) ((sample << 5) & 0x20);
sample += (original >> 4) & 0x1;
temp |= (byte) ((sample << 4) & 0x10);
sample += (original >> 3) & 0x1;
temp |= (byte) ((sample << 3) & 0x08);
sample += (original >> 2) & 0x1;
temp |= (byte) ((sample << 2) & 0x04);
sample += (original >> 1) & 0x1;
temp |= (byte) ((sample << 1) & 0x02);
sample += original & 0x1;
array[b] = (byte) (temp | sample & 0x1);
}
break;
case 2:
for (int b = 0; b < (columns + 3) / 4; b++) {
original = array[b];
sample += (original >> 6) & 0x3;
temp = (byte) ((sample << 6) & 0xc0);
sample += (original >> 4) & 0x3;
temp |= (byte) ((sample << 4) & 0x30);
sample += (original >> 2) & 0x3;
temp |= (byte) ((sample << 2) & 0x0c);
sample += original & 0x3;
array[b] = (byte) (temp | sample & 0x3);
}
break;
case 4:
for (int b = 0; b < (columns + 1) / 2; b++) {
original = array[b];
sample += (original >> 4) & 0xf;
temp = (byte) ((sample << 4) & 0xf0);
sample += original & 0x0f;
array[b] = (byte) (temp | sample & 0xf);
}
break;
case 8:
for (int x = 1; x < columns; x++) {
for (int b = 0; b < samplesPerPixel; b++) {
int off = x * samplesPerPixel + b;
array[off] = (byte) (array[off - samplesPerPixel] + array[off]);
}
}
break;
case 16:
for (int x = 1; x < columns; x++) {
for (int b = 0; b < samplesPerPixel; b++) {
int off = x * samplesPerPixel + b;
buffer.putShort(2 * off, (short) (buffer.getShort(2 * (off - samplesPerPixel)) + buffer.getShort(2 * off)));
}
}
break;
case 32:
for (int x = 1; x < columns; x++) {
for (int b = 0; b < samplesPerPixel; b++) {
int off = x * samplesPerPixel + b;
buffer.putInt(4 * off, buffer.getInt(4 * (off - samplesPerPixel)) + buffer.getInt(4 * off));
}
}
break;
case 64:
for (int x = 1; x < columns; x++) {
for (int b = 0; b < samplesPerPixel; b++) {
int off = x * samplesPerPixel + b;
buffer.putLong(8 * off, buffer.getLong(8 * (off - samplesPerPixel)) + buffer.getLong(8 * off));
}
}
break;
default:
throw new AssertionError(String.format("Unsupported bits per sample value: %d", bitsPerSample));
}
}
@Override
public int read() throws IOException {
if (!buffer.hasRemaining()) {
if (!fetch()) {
return -1;
}
}
return buffer.get() & 0xff;
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
if (!buffer.hasRemaining()) {
if (!fetch()) {
return -1;
}
}
int read = Math.min(buffer.remaining(), len);
buffer.get(b, off, read);
return read;
}
@Override
public long skip(long n) throws IOException {
if (n < 0) {
return 0;
}
if (!buffer.hasRemaining()) {
if (!fetch()) {
return 0; // SIC
}
}
int skipped = (int) Math.min(buffer.remaining(), n);
buffer.position(buffer.position() + skipped);
return skipped;
}
@Override
public void close() throws IOException {
try {
super.close();
}
finally {
if (channel.isOpen()) {
channel.close();
}
}
}
}