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This package supports the parsing of AIS messages in Java. AIS, the Automatic Identification System, is a system aiming at improving maritime safety by exchanging messages between ships, other vehicles in particular aircraft involved in search-and-rescue (SAR), and (fixed) base stations. To be precise, this package support the ITU-R M.1371-4 AIS standard. See our extensive javadoc and in particular the class AISParser for more information on how to use this package. The parser was used in the Poseidon project, and is improved in the Metis project to better handle uncertain information. Both projects were led by the Embedded Systems Institute. In both projects Thales Nederlands was the carrying industrial partner, and multiple Dutch universities participated.

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package nl.esi.metis.aisparser.impl;

import java.text.NumberFormat;

import nl.esi.metis.aisparser.AISMessage05;
import nl.esi.metis.aisparser.Sixbit;
import nl.esi.metis.aisparser.UtilsDimensions30;
import nl.esi.metis.aisparser.UtilsEta;
import nl.esi.metis.aisparser.UtilsPositioningDevice;
import nl.esi.metis.aisparser.UtilsShipType8;
import nl.esi.metis.aisparser.UtilsSpare;
import nl.esi.metis.aisparser.UtilsString;
import nl.esi.metis.aisparser.annotations.AISIllegalValueAnnotation;
import nl.esi.metis.aisparser.provenance.VDMMessageProvenance;

import cern.colt.bitvector.BitVector;

/** ESI AIS Parser
 * 
 * Copyright 2011/2012 by Pierre van de Laar (Embedded Systems Institute)
 * Copyright 2008 by Brian C. Lane 
 * All Rights Reserved
 * 
 * @author Pierre van de Laar
 * @author Brian C. Lane
 */

/** AIS Message 5 implementation: Ship Static and Voyage Related Data.
 *  * Field Nr     Field Name                          NrOf Bits   (from, to )
 * ------------------------------------------------------------------------
 *  1	messageID                               	   6	(   1,   6)
 *  2	repeatIndicator                         	   2	(   7,   8)
 *  3	userID                                  	  30	(   9,  38)
 *  4	aisVersionIndicator                     	   2	(  39,  40)
 *  5	imoNumber                               	  30	(  41,  70)
 *  6	callSign                                	  42	(  71, 112)
 *  7	name                                    	 120	( 113, 232)
 *  8	typeOfShipAndCargoType                  	   8	( 233, 240)
 *  9	dimension                               	  30	( 241, 270)
 * 10	typeOfElectronicPositionFixingDevice    	   4	( 271, 274)
 * 11	eta                                     	  20	( 275, 294)
 * 12	maximumPresentStaticDraught             	   8	( 295, 302)
 * 13	destination                             	 120	( 303, 422)
 * 14	dte                                     	   1	( 423, 423)
 * 15	spare                                   	   1	( 424, 424)
 *                                                  ---- +
 *                       (maximum) number of bits    424
 * 
 */
class AISMessage05Impl extends AISMessageImpl implements AISMessage05 {
	public static final int LENGTH = 424;
	public static boolean validLength(int length)
	{
		return (length == LENGTH);
	}
	
	/**
	 * Return the difference in available and needed bits to parse this sixbit as an AISMessage05
	 * A positive difference indicates that there are more bits available than needed by the standard.
	 * @param sb
	 * @return
	 */
	public static int differenceInBits(Sixbit sb)
	{
		return (sb.available() - LENGTH);
	}

	private static final int AISVERSIONINDICATOR_FROM = 39;
	private static final int AISVERSIONINDICATOR_TO = 40;

	private int aisVersionIndicator;
	/** aisVersionIndicator
	 * @return int value of aisVersionIndicator (2 bits [39,40])
	 */
	public int getAisVersionIndicator() { return aisVersionIndicator; }


	private static final int IMONUMBER_FROM = 41;
	private static final int IMONUMBER_TO = 70;

	private int imoNumber;
	/** imoNumber
	 * @return int value of imoNumber (30 bits [41,70])
	 */
	public int getImoNumber() { return imoNumber; }


	private static final int CALLSIGN_FROM = 71;
	private static final int CALLSIGN_TO = 112;

	private String callSign;
	/** callSign
	 * @return String value of callSign (42 bits [71,112])
	 */
	public String getCallSign() { return callSign; }


	private static final int NAME_FROM = 113;
	private static final int NAME_TO = 232;

	private String name;
	/** name
	 * @return String value of name (120 bits [113,232])
	 */
	public String getName() { return name; }


	private static final int TYPEOFSHIPANDCARGOTYPE_FROM = 233;
	private static final int TYPEOFSHIPANDCARGOTYPE_TO = 240;

	private int typeOfShipAndCargoType;
	/** typeOfShipAndCargoType
	 * @return int value of typeOfShipAndCargoType (8 bits [233,240])
	 */
	public int getTypeOfShipAndCargoType() { return typeOfShipAndCargoType; }


	private static final int DIMENSION_FROM = 241;
	private static final int DIMENSION_TO = 270;

	private BitVector dimension;
	/** dimension
	 * @return BitVector value of dimension (30 bits [241,270])
	 */
	public BitVector getDimension() { return dimension; }


	private static final int TYPEOFELECTRONICPOSITIONFIXINGDEVICE_FROM = 271;
	private static final int TYPEOFELECTRONICPOSITIONFIXINGDEVICE_TO = 274;

	private int typeOfElectronicPositionFixingDevice;
	/** typeOfElectronicPositionFixingDevice
	 * @return int value of typeOfElectronicPositionFixingDevice (4 bits [271,274])
	 */
	public int getTypeOfElectronicPositionFixingDevice() { return typeOfElectronicPositionFixingDevice; }


	private static final int ETA_FROM = 275;
	private static final int ETA_TO = 294;

	private BitVector eta;
	/** eta
	 * @return BitVector value of eta (20 bits [275,294])
	 */
	public BitVector getEta() { return eta; }


	private static final int MAXIMUMPRESENTSTATICDRAUGHT_FROM = 295;
	private static final int MAXIMUMPRESENTSTATICDRAUGHT_TO = 302;

	private int maximumPresentStaticDraught;
	/** maximumPresentStaticDraught
	 * @return int value of maximumPresentStaticDraught (8 bits [295,302])
	 */
	public int getMaximumPresentStaticDraught() { return maximumPresentStaticDraught; }


	private static final int DESTINATION_FROM = 303;
	private static final int DESTINATION_TO = 422;

	private String destination;
	/** destination
	 * @return String value of destination (120 bits [303,422])
	 */
	public String getDestination() { return destination; }


	private static final int DTE_BITINDEX = 423;

	private boolean dte;
	/** dte
	 * @return boolean value of dte (bit 423)
	 */
	public boolean getDte() { return dte; }


	private static final int SPARE_FROM = 424;
	private static final int SPARE_TO = 424;

	private int spare;
	/** spare
	 * @return int value of spare (1 bits [424,424])
	 */
	public int getSpare() { return spare; }
	
	/** A number format specifying that at least two digits should be used */
	private static NumberFormat twoDigits = NumberFormat.getIntegerInstance();
	
	static {
		twoDigits.setMinimumIntegerDigits(2);
	}
	
	/** Generates a String representing the AIS message. 
	 * Format: all fields are shown in the order and units as specified by the standard separated by the SEPARATOR string.
	 */
	@Override
	public String toString() {
		String result = super.toString();
		result += SEPARATOR + Integer.toString(imoNumber);
		result += SEPARATOR + callSign;
		result += SEPARATOR + name;
		result += SEPARATOR + UtilsShipType8.shipTypeToString(typeOfShipAndCargoType);
		result += SEPARATOR + UtilsDimensions30.toString(dimension);
		String etaString = twoDigits.format(UtilsEta.getMonth(eta)) + "-" + twoDigits.format(UtilsEta.getDay(eta))
				   + "T" + twoDigits.format(UtilsEta.getHour(eta))  + ":" + twoDigits.format(UtilsEta.getMinute(eta));
		result += SEPARATOR + etaString;
		result += SEPARATOR + UtilsPositioningDevice.toString(typeOfElectronicPositionFixingDevice);
		result += SEPARATOR + destination;
		result += SEPARATOR + (dte ? "no DTE" : "with DTE");
		return result;
	}

	/** AISMessage 5 constructor
	 * @param content AIS content
	 * @param prov the provenance of the message
	 * @precondition validLength(content.length()) && AISMessageBase.getMessageId(content)== 5
	 */
	public AISMessage05Impl(Sixbit content, VDMMessageProvenance prov)
	{
		super(content, prov);
		assert(validLength(content.length()));
		assert(getMessageID() == 5);
		
		aisVersionIndicator = content.getIntFromTo(AISVERSIONINDICATOR_FROM,AISVERSIONINDICATOR_TO);
		imoNumber = content.getIntFromTo(IMONUMBER_FROM,IMONUMBER_TO);
		callSign = UtilsString.stripAtSigns(content.getStringFromTo(CALLSIGN_FROM,CALLSIGN_TO));
		name = UtilsString.stripAtSigns(content.getStringFromTo(NAME_FROM,NAME_TO));
		typeOfShipAndCargoType = content.getIntFromTo(TYPEOFSHIPANDCARGOTYPE_FROM,TYPEOFSHIPANDCARGOTYPE_TO);
		dimension = content.getBitVectorFromTo(DIMENSION_FROM,DIMENSION_TO);
		typeOfElectronicPositionFixingDevice = content.getIntFromTo(TYPEOFELECTRONICPOSITIONFIXINGDEVICE_FROM,TYPEOFELECTRONICPOSITIONFIXINGDEVICE_TO);
		eta = content.getBitVectorFromTo(ETA_FROM,ETA_TO);
		maximumPresentStaticDraught = content.getIntFromTo(MAXIMUMPRESENTSTATICDRAUGHT_FROM,MAXIMUMPRESENTSTATICDRAUGHT_TO);
		destination = UtilsString.stripAtSigns(content.getStringFromTo(DESTINATION_FROM,DESTINATION_TO));
		dte = content.getBoolean(DTE_BITINDEX);
		spare = content.getIntFromTo(SPARE_FROM,SPARE_TO);
		if (!UtilsSpare.isSpareSemanticallyCorrect(spare))
	    {
	    	annotations.add(new AISIllegalValueAnnotation("getSpare", spare, UtilsSpare.range));
	    }
	}    
}