PNGChunk.java

/*
 * 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.png.chunks;

import java.io.ByteArrayInputStream;

import org.apache.sanselan.common.BinaryFileParser;

public class PNGChunk extends BinaryFileParser
{
    public final int length;
    public final int chunkType;
    public final int crc;
    public final byte bytes[];

    public final boolean propertyBits[];
    public final boolean ancillary, isPrivate, reserved, safeToCopy;

    public PNGChunk(int Length, int ChunkType, int CRC, byte bytes[])
    {
        this.length = Length;
        this.chunkType = ChunkType;
        this.crc = CRC;
        this.bytes = bytes;

        propertyBits = new boolean[4];
        int shift = 24;
        for (int i = 0; i < 4; i++)
        {
            int theByte = 0xff & (ChunkType >> shift);
            shift -= 8;
            int theMask = 1 << 5;
            propertyBits[i] = ((theByte & theMask) > 0);
        }

        ancillary = propertyBits[0];
        isPrivate = propertyBits[1];
        reserved = propertyBits[2];
        safeToCopy = propertyBits[3];
    }

    protected ByteArrayInputStream getDataStream()
    {
        ByteArrayInputStream is = new ByteArrayInputStream(bytes);
        return is;
    }

}