/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.sanselan.formats.tiff.datareaders;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.apache.sanselan.ImageReadException;
import org.apache.sanselan.common.BinaryConstants;
import org.apache.sanselan.common.BitInputStream;
import org.apache.sanselan.common.PackBits;
import org.apache.sanselan.common.mylzw.MyLZWDecompressor;
import org.apache.sanselan.formats.tiff.constants.TiffConstants;
import org.apache.sanselan.formats.tiff.photometricinterpreters.PhotometricInterpreter;
public abstract class DataReader implements TiffConstants, BinaryConstants
{
protected final PhotometricInterpreter photometricInterpreter;
protected final int bitsPerSample[];
protected final int last[];
protected final int predictor;
protected final int samplesPerPixel;
public DataReader(PhotometricInterpreter photometricInterpreter,
int bitsPerSample[], int predictor, int samplesPerPixel)
{
this.photometricInterpreter = photometricInterpreter;
this.bitsPerSample = bitsPerSample;
this.samplesPerPixel = samplesPerPixel;
this.predictor = predictor;
last = new int[samplesPerPixel];
}
// public abstract void readImageData(BufferedImage bi, ByteSource byteSource)
public abstract void readImageData(BufferedImage bi)
throws ImageReadException, IOException;
protected int[] getSamplesAsBytes(BitInputStream bis)
throws ImageReadException, IOException
{
int result[] = new int[bitsPerSample.length];
for (int i = 0; i < bitsPerSample.length; i++)
{
int bits = bitsPerSample[i];
int sample = bis.readBits(bits);
if (bits < 8)
{
int sign = sample & 1;
sample = sample << (8 - bits); // scale to byte.
if (sign > 0)
sample = sample | ((1 << (8 - bits)) - 1); // extend to byte
}
else if (bits > 8)
{
sample = sample >> (bits - 8); // extend to byte.
}
result[i] = sample;
}
return result;
}
protected int[] applyPredictor(int samples[], int x)
{
if (predictor == 2) // Horizontal differencing.
{
for (int i = 0; i < samples.length; i++)
{
if (x > 0)
{
samples[i] = 0xff & (samples[i] + last[i]);
}
last[i] = samples[i];
}
}
return samples;
}
private int count = 0;
protected byte[] decompress(byte compressed[], int compression,
int expected_size) throws ImageReadException, IOException
{
switch (compression)
{
case 1 : // None;
return compressed;
case 2 : // CCITT Group 3 1-Dimensional Modified Huffman run-length encoding.
throw new ImageReadException("Tiff: unknown compression: "
+ compression);
case TIFF_COMPRESSION_LZW : // LZW
{
InputStream is = new ByteArrayInputStream(compressed);
int LZWMinimumCodeSize = 8;
MyLZWDecompressor myLzwDecompressor = new MyLZWDecompressor(
LZWMinimumCodeSize, BYTE_ORDER_NETWORK);
myLzwDecompressor.setTiffLZWMode();
byte[] result = myLzwDecompressor.decompress(is, expected_size);
return result;
}
case TIFF_COMPRESSION_PACKBITS : // Packbits
{
byte unpacked[] = new PackBits().decompress(compressed,
expected_size);
count++;
return unpacked;
}
default :
throw new ImageReadException("Tiff: unknown compression: "
+ compression);
}
}
}