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/*
* 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.tiff;
import com.twelvemonkeys.lang.Validate;
import java.io.EOFException;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* Input stream that provides on-the-fly upsampling of TIFF subsampled YCbCr samples.
*
* @author Harald Kuhr
* @author last modified by $Author: haraldk$
* @version $Id: YCbCrUpsamplerStream.java,v 1.0 31.01.13 09:25 haraldk Exp$
*/
final class YCbCrUpsamplerStream extends FilterInputStream {
private final int horizChromaSub;
private final int vertChromaSub;
private final int yCbCrPos;
private final int columns;
private final int units;
private final int unitSize;
private final int padding;
private final byte[] decodedRows;
int decodedLength;
int decodedPos;
private final byte[] buffer;
int bufferLength;
int bufferPos;
public YCbCrUpsamplerStream(final InputStream stream, final int[] chromaSub, final int yCbCrPos, final int columns) {
super(Validate.notNull(stream, "stream"));
Validate.notNull(chromaSub, "chromaSub");
Validate.isTrue(chromaSub.length == 2, "chromaSub.length != 2");
this.horizChromaSub = chromaSub[0];
this.vertChromaSub = chromaSub[1];
this.yCbCrPos = yCbCrPos;
this.columns = columns;
// In TIFF, subsampled streams are stored in "units" of horiz * vert pixels.
// For a 4:2 subsampled stream like this:
//
// Y0 Y1 Y2 Y3 Cb0 Cr0 Y8 Y9 Y10 Y11 Cb1 Cr1
// Y4 Y5 Y6 Y7 Y12Y13Y14 Y15
//
// In the stream, the order is: Y0,Y1,Y2..Y7,Cb0,Cr0, Y8...Y15,Cb1,Cr1, Y16...
unitSize = horizChromaSub * vertChromaSub + 2;
units = (columns + horizChromaSub - 1) / horizChromaSub; // If columns % horizChromasSub != 0...
padding = units * horizChromaSub - columns; // ...each coded row will be padded to fill unit
decodedRows = new byte[columns * vertChromaSub * 3];
buffer = new byte[unitSize * units];
}
private void fetch() throws IOException {
if (bufferPos >= bufferLength) {
int pos = 0;
int read;
// This *SHOULD* read an entire row of units into the buffer, otherwise decodeRows will throw EOFException
while (pos < buffer.length && (read = in.read(buffer, pos, buffer.length - pos)) > 0) {
pos += read;
}
bufferLength = pos;
bufferPos = 0;
}
if (bufferLength > 0) {
decodeRows();
}
else {
decodedLength = -1;
}
}
private void decodeRows() throws EOFException {
decodedLength = decodedRows.length;
for (int u = 0; u < units; u++) {
if (bufferPos >= bufferLength) {
throw new EOFException("Unexpected end of stream");
}
// Decode one unit
byte cb = buffer[bufferPos + unitSize - 2];
byte cr = buffer[bufferPos + unitSize - 1];
for (int y = 0; y < vertChromaSub; y++) {
for (int x = 0; x < horizChromaSub; x++) {
// Skip padding at end of row
int column = horizChromaSub * u + x;
if (column >= columns) {
bufferPos += padding;
break;
}
int pixelOff = 3 * (column + columns * y);
decodedRows[pixelOff] = buffer[bufferPos++];
decodedRows[pixelOff + 1] = cb;
decodedRows[pixelOff + 2] = cr;
}
}
bufferPos += 2; // Skip CbCr bytes at end of unit
}
bufferPos = bufferLength;
decodedPos = 0;
}
@Override
public int read() throws IOException {
if (decodedLength < 0) {
return -1;
}
if (decodedPos >= decodedLength) {
fetch();
if (decodedLength < 0) {
return -1;
}
}
return decodedRows[decodedPos++] & 0xff;
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
if (decodedLength < 0) {
return -1;
}
if (decodedPos >= decodedLength) {
fetch();
if (decodedLength < 0) {
return -1;
}
}
int read = Math.min(decodedLength - decodedPos, len);
System.arraycopy(decodedRows, decodedPos, b, off, read);
decodedPos += read;
return read;
}
@Override
public long skip(long n) throws IOException {
if (decodedLength < 0) {
return -1;
}
if (decodedPos >= decodedLength) {
fetch();
if (decodedLength < 0) {
return -1;
}
}
int skipped = (int) Math.min(decodedLength - decodedPos, n);
decodedPos += skipped;
return skipped;
}
@Override
public boolean markSupported() {
return false;
}
@Override
public synchronized void reset() throws IOException {
throw new IOException("mark/reset not supported");
}
private static byte clamp(int val) {
return (byte) Math.max(0, Math.min(255, val));
}
}
