de.intarsys.pdf.st.COSObjectStream Maven / Gradle / Ivy

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/*
 * Copyright (c) 2007, intarsys consulting GmbH
 *
 * 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 intarsys 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 OWNER 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
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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package de.intarsys.pdf.st;

import java.io.IOException;

import de.intarsys.pdf.cos.COSBasedObject;
import de.intarsys.pdf.cos.COSName;
import de.intarsys.pdf.cos.COSObject;
import de.intarsys.pdf.cos.COSStream;
import de.intarsys.pdf.parser.COSDocumentParser;
import de.intarsys.pdf.parser.COSLoadException;
import de.intarsys.tools.randomaccess.IRandomAccess;
import de.intarsys.tools.randomaccess.RandomAccessByteArray;

/**
 * A COSStream containing other COSObjects.
 */
public class COSObjectStream extends COSBasedObject {
	/**
	 * The meta class implementation
	 */
	public static class MetaClass extends COSBasedObject.MetaClass {
		protected MetaClass(Class instanceClass) {
			super(instanceClass);
		}

		@Override
		protected COSBasedObject doCreateCOSBasedObject(COSObject object) {
			return new COSObjectStream(object);
		}
	}

	/** The meta class instance */
	static public final MetaClass META = new MetaClass(MetaClass.class
			.getDeclaringClass());

	public static final COSName CN_Type_ObjStm = COSName.constant("ObjStm"); //$NON-NLS-1$

	public static final COSName DK_First = COSName.constant("First"); //$NON-NLS-1$

	public static final COSName DK_N = COSName.constant("N"); //$NON-NLS-1$

	public static final COSName DK_Extends = COSName.constant("Extends"); //$NON-NLS-1$

	private COSStream stream;

	private int[][] objectTable;

	private IRandomAccess randomAccess;

	protected COSObjectStream(COSObject stream) {
		super(((COSStream) stream).getDict());
		this.stream = (COSStream) stream;
	}

	public int getFirst() {
		return getFieldInt(DK_First, -1);
	}

	public int getN() {
		return getFieldInt(DK_N, 0);
	}

	private int getOffsetByIndex(int index, COSDocumentParser parser)
			throws IOException {
		if (objectTable == null) {
			objectTable = new int[getN()][2];
			getRandomAccess().seek(0);
			for (int i = 0; i < objectTable.length; i++) {
				objectTable[i][0] = parser.readInteger(getRandomAccess(), true);
				objectTable[i][1] = parser.readInteger(getRandomAccess(), true);
			}
		}
		return objectTable[index][1];
	}

	protected IRandomAccess getRandomAccess() throws IOException {
		if (randomAccess == null) {
			randomAccess = new RandomAccessByteArray(stream.getDecodedBytes());
		}
		return randomAccess;
	}

	public COSObject loadObject(int index, COSDocumentParser parser)
			throws IOException, COSLoadException {
		if (index >= getN()) {
			return null;
		}
		int offset = getOffsetByIndex(index, parser);
		getRandomAccess().seek(getFirst() + offset);
		return (COSObject) parser.parseElement(getRandomAccess());
	}

	public void parse(int index, COSDocumentParser parser) throws IOException,
			COSLoadException {
		if (index >= getN()) {
			return;
		}
		int offset = getOffsetByIndex(index, parser);
		getRandomAccess().seek(getFirst() + offset);
		parser.parseElement(getRandomAccess());
	}
}