de.intarsys.pdf.st.XRefStreamWriter 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
 * 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 de.intarsys.pdf.st;

import java.io.IOException;
import java.util.Iterator;

import de.intarsys.pdf.cos.COSArray;
import de.intarsys.pdf.cos.COSIndirectObject;
import de.intarsys.pdf.cos.COSInteger;
import de.intarsys.pdf.writer.COSWriter;
import de.intarsys.tools.randomaccess.RandomAccessByteArray;

/**
 * A XRef serializer to a XRef stream.
 */
public class XRefStreamWriter extends AbstractXRefWriter {
	/**
	 * 
	 */
	class SearchVisitor implements IXRefEntryVisitor {
		private long highestOffset = 0;

		private int highestGeneration = 0;

		private void checkGeneration(int generation) {
			if (generation > highestGeneration) {
				highestGeneration = generation;
			}
		}

		private void checkOffset(long offset) {
			if (offset > highestOffset) {
				highestOffset = offset;
			}
		}

		public int getHighestGeneration() {
			return highestGeneration;
		}

		public long getHighestOffset() {
			return highestOffset;
		}

		public void visitFromCompressed(STXRefEntryCompressed entry) {
			checkOffset(entry.getStreamObjectNumber());
			checkGeneration(entry.getIndex());
		}

		public void visitFromFree(STXRefEntryFree entry) {
			checkOffset(entry.getNextFreeObjectNumber());
			checkGeneration(entry.getGenerationNumber());
		}

		public void visitFromOccupied(STXRefEntryOccupied entry) {
			checkOffset(entry.getOffset());
			checkGeneration(entry.getGenerationNumber());
		}
	}

	public static byte[] TYPE_FREE = { 0 };

	public static byte[] TYPE_OCCUPIED = { 1 };

	public static byte[] TYPE_COMPRESSED = { 2 };

	private int[] wSize;

	public XRefStreamWriter(COSWriter cosWriter) {
		super(cosWriter);
	}

	private int byteSizeOf(int number) {
		int mask = 0xff000000;
		for (int size = 4; size > 0; size--) {
			if ((number & mask) != 0) {
				return size;
			}
			mask = mask >> 8;
		}
		return 0;
	}

	@Override
	protected void finish(STXRefSection xRefSection) throws IOException {
		byte[] innerBytes = ((RandomAccessByteArray) getRandomAccess())
				.toByteArray();
		((STStreamXRefSection) xRefSection).cosGetStream().setDecodedBytes(
				innerBytes);
		getCosWriter().writeIndirectObject(
				((STStreamXRefSection) xRefSection).cosGetStream()
						.getIndirectObject());
		super.finish(xRefSection);
	}

	@Override
	protected byte[] getTypeCompressed() {
		return TYPE_COMPRESSED;
	}

	@Override
	protected byte[] getTypeFree() {
		return TYPE_FREE;
	}

	@Override
	protected byte[] getTypeOccupied() {
		return TYPE_OCCUPIED;
	}

	@Override
	protected void initialize(STXRefSection xRefSection) throws IOException {
		super.initialize(xRefSection);
		STStreamXRefSection xrefStream = (STStreamXRefSection) xRefSection;
		setRandomAccess(new RandomAccessByteArray(null));
		initWSize(xrefStream);
		xrefStream.setIndex(COSArray.create());
		COSIndirectObject io = xrefStream.cosGetStream().getIndirectObject();
		int objectNumber = io.getObjectNumber();
		int generationNumber = io.getGenerationNumber();
		if (objectNumber == -1) {
			int size = xrefStream.getSize();
			objectNumber = size;
			generationNumber = 0;
			xrefStream.cosGetStream().getIndirectObject().setKey(objectNumber,
					generationNumber);
			xrefStream.setSize(size + 1);
		}
		xRefSection.addEntry(new STXRefEntryOccupied(objectNumber,
				generationNumber, xRefSection.getOffset()));
	}

	private void initWSize(STXRefSection xRefSection) {
		// search highest 2nd column
		SearchVisitor search = new SearchVisitor();

		for (Iterator i = xRefSection.entryIterator(); i.hasNext();) {
			STXRefEntry entry = ((STXRefEntry) i.next());
			try {
				entry.accept(search);
			} catch (XRefEntryVisitorException e) {
				// won't happen
			}
		}
		wSize = new int[3];
		wSize[0] = 1;
		wSize[1] = byteSizeOf((int) search.getHighestOffset());
		wSize[2] = byteSizeOf(search.getHighestGeneration());

		COSArray wArray = COSArray.create(3);
		for (int i = 0; i < 3; i++) {
			wArray.add(COSInteger.create(wSize[i]));
		}
		((STStreamXRefSection) xRefSection).setW(wArray);
	}

	@Override
	protected void visitFromSubsection(STXRefSubsection section) {
		COSArray index = ((STStreamXRefSection) section.getXRefSection())
				.getIndex();
		index.add(COSInteger.create(section.getStart()));
		index.add(COSInteger.create(section.getSize()));
	}

	private void write(int data, int numBytes) throws IOException {
		switch (numBytes) {
		case 4:
			getRandomAccess().write((data & 0xFF000000) >> 24);
		case 3:
			getRandomAccess().write((data & 0x00FF0000) >> 16);
		case 2:
			getRandomAccess().write((data & 0x0000FF00) >> 8);
		case 1:
			getRandomAccess().write(data & 0x000000FF);
			break;
		default:

			// should not happen
		}
	}

	@Override
	protected void write(int col1, int col2, byte[] type) throws IOException {
		getRandomAccess().write(type);
		write(col1, wSize[1]);
		write(col2, wSize[2]);
	}
}