TableC.java

/*
 * Copyright (C) 2008 Steve Ratcliffe
 * 
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 * 
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 * 
 * 
 * Author: Steve Ratcliffe, Robert Vollmert
 * Create date: 18-Jul-2008
 */
package uk.me.parabola.imgfmt.app.net;

import java.util.ArrayList;
import java.util.List;

import uk.me.parabola.imgfmt.FormatException;
import uk.me.parabola.imgfmt.app.ImgFileWriter;

/**
 * @author Steve Ratcliffe, Robert Vollmert
 */
public class TableC {
	// size of the table, excluding the size field
	private int size;

	private final TableA tabA;

	private final List<RouteRestriction> restrictions = new ArrayList<RouteRestriction>();

	public TableC(TableA tabA) {
		this.tabA = tabA;
	}

	/**
	 * Write the table including size field.
	 */
	public void write(ImgFileWriter writer, int tablesOffset) {
		if (!restrictions.isEmpty()) {
			if (size < 0x100)
				writer.put((byte) size);
			else
				writer.putChar((char) size);
			for (RouteRestriction restr : restrictions)
				restr.write(writer, tablesOffset);
		}
		if(tabA.numRoundaboutArcs() > 0)
			writer.put((byte)tabA.numRoundaboutArcs());
		if(tabA.numUnpavedArcs() > 0)
			writer.put((byte)tabA.numUnpavedArcs());
		if(tabA.numFerryArcs() > 0)
			writer.put((byte)tabA.numFerryArcs());
	}

	/**
	 * Add a restriction.
	 *
	 * @param restr A new restriction.
	 * @return The offset into Table C at which the restriction will
	 *         be written.
	 */
	public int addRestriction(RouteRestriction restr) {
		int offset = size;
		restrictions.add(restr);
		size += restr.getSize();
		return offset;
	}

	/**
	 * The size of restriction indices in the nodes area.
	 */
	private byte getOffsetSize() {
		if (size < 0x80)
			return 1; // allows 7 bit index (8th bit is flag)
		else if (size < 0x8000)
			return 2; // allows 15 bit index (16th bit is flag)
		else
			// XXX: haven't seen larger than 2, may well be possible
			throw new FormatException("too many restrictions");
	}

	public void propagateSizeBytes() {
		byte b = getOffsetSize();
		for (RouteRestriction restr : restrictions)
			restr.setOffsetSize(b);
	}

	public byte getFormat() {
		// Table C format bitmask
		// 0x01 = 1-255 bytes of restrictions
		// 0x02 = 256-65535 bytes of restrictions
		// 0x08 = unpaved roads count present
		// 0x10 = ferry count present
		int format = 0;
		if(size > 0) {
			++format;
			if(size > 0xff)
				++format;
		}
		if(tabA.numRoundaboutArcs() > 0)
			format |= 0x04;
		if(tabA.numUnpavedArcs() > 0)
			format |= 0x08;
		if(tabA.numFerryArcs() > 0)
			format |= 0x10;
		return (byte)format;
	}
}