/***************************************
 *            ViPER-MPEG               *
 *  The Video Processing               *
 *         Evaluation Resource         *
 *             MPEG-1 Decoder          *
 * Distributed under the LGPL license  *
 *        Terms available at gnu.org.  *
 *                                     *
 *  Copyright University of Maryland,  *
 *                      College Park.  *
 ***************************************/

package edu.umd.cfar.lamp.mpeg1.video;

import java.util.*;

/** Indexes within a Group of Pictures. */
public class GroupOfPicturesIndex
{
	private Vector  codingOrderIndex    = null;
	private Vector  displayOrderIndex   = null;
	private boolean displayOrderIndexed = false;


	public GroupOfPicturesIndex()
	{
		codingOrderIndex = new Vector();
	}

	/** 
	 * Adds a <code>GroupOfPicturesIndexElement</code>, which 
	 * represents one picture (frame) in the Group of Pictures, to 
	 * the index.
	 * @param startPosition the start position
	 * @param dataSize the data length
	 * @param type 
	 * @param displayOrder
	 */
	public void addPicture(long startPosition, long dataSize, byte type, int displayOrder)
	{
		codingOrderIndex.add(new GroupOfPicturesIndexElement(startPosition, dataSize, type, displayOrder));
		displayOrderIndexed = false;
	}

	/**
	 * @param n the frame
	 * @return the byte position (in the video stream) of  the 
	 * (zero-based) <code>n</code>th picture (frame) in this Group 
	 * Of Pictures (in display order). 
	 * @throws FrameNotFoundException
	 */
	public long getPositionOfPicture(int n) throws FrameNotFoundException
	{
		try
		{
			return ((GroupOfPicturesIndexElement)getElementsInDisplayOrder().elementAt(n)).getStartPosition();
		}
		catch (ArrayIndexOutOfBoundsException e)
		{
			throw new FrameNotFoundException("Picture " + n + " not in " + this);
		}
	}

	public int getLastIOrPPicture(int n) throws FrameNotFoundException
	{
		Vector codingOrder = getElementsInCodingOrder();

		int codingOrderIndex = mapDisplayOrderToCodingOrder(n);
		for (int i = codingOrderIndex-1; i >= 0; i--)
		{
			switch (((GroupOfPicturesIndexElement)codingOrder.elementAt(i)).getType())
			{
				case PictureCodingTypes.TYPE_I:
				case PictureCodingTypes.TYPE_P: return mapCodingOrderToDisplayOrder(i);
			}
		}

		throw new FrameNotFoundException();
	}

	public int getLastIOrPPicture() throws FrameNotFoundException
	{
		Vector codingOrder = getElementsInCodingOrder();

		for (int i = codingOrder.size()-1; i >= 0; i--)
		{
			switch (((GroupOfPicturesIndexElement)codingOrder.elementAt(i)).getType())
			{
				case PictureCodingTypes.TYPE_I:
				case PictureCodingTypes.TYPE_P: return mapCodingOrderToDisplayOrder(i);
			}
		}

		throw new FrameNotFoundException();
	}

	public long getPositionOfPictureInCodingOrder(int n) throws FrameNotFoundException
	{
		try
		{
			return ((GroupOfPicturesIndexElement)getElementsInCodingOrder().elementAt(n)).getStartPosition();
		}
		catch (ArrayIndexOutOfBoundsException e)
		{
			throw new FrameNotFoundException();
		}
	}
	/** @return a <code>Vector<code> of <code>GroupOfPicturesIndexElement</code>s in display order. */
	public Vector getElementsInDisplayOrder()
	{
		if (!displayOrderIndexed)
		{
			displayOrderIndex = (Vector)codingOrderIndex.clone();
			Collections.sort(displayOrderIndex);
			displayOrderIndexed = true;
		}
		return displayOrderIndex;
	}

	/** @return a <code>Vector<code> of <code>GroupOfPicturesIndexElement</code>s in coding order. */
	public Vector getElementsInCodingOrder()
	{
		return codingOrderIndex;
	}

	/** 
	 * Maps a (0-based) frame in dislay order to a (0-based) frame in coding order. 
	 * @param displayOrder
	 * @return
	 * @throws FrameNotFoundException
	 */
	public int mapDisplayOrderToCodingOrder(int displayOrder) throws FrameNotFoundException
	{
		int i = codingOrderIndex.indexOf(getElementsInDisplayOrder().elementAt(displayOrder));
		if (i == -1)
			throw new FrameNotFoundException();
		return i;
	}

	/** 
	 * Maps a (0-based) frame in coding order to a (0-based) frame in display order. 
	 * @param codingOrder
	 * @return
	 * @throws FrameNotFoundException
	 */
	public int mapCodingOrderToDisplayOrder(int codingOrder) throws FrameNotFoundException
	{
		int i = getElementsInDisplayOrder().indexOf(codingOrderIndex.elementAt(codingOrder));
		if (i == -1)
			throw new FrameNotFoundException();
		return i;
	}

	/** 
	 * Returns the type of the (0-based) frame in coding order.
	 * @param n
	 * @return
	 * @throws FrameNotFoundException
	 */
	public byte getTypeOfPictureInCodingOrder(int n) throws FrameNotFoundException
	{
		return ((GroupOfPicturesIndexElement)codingOrderIndex.elementAt(n)).getType();
	}

	public byte getTypeOfPicture(int n) throws FrameNotFoundException
	{
		return ((GroupOfPicturesIndexElement)getElementsInDisplayOrder().elementAt(n)).getType();
	}

	public String toString()
	{
		return "(" + codingOrderIndex + ")";
	}
}