git_bsmd/AIS/bsmd.AIS2Service/AIS_ClassB.cs

using System;
using System.Collections;
using System.Text;
using System.Diagnostics;
using log4net;

namespace bsmd.AIS2Service
{
    internal class AIS_ClassB : AISClass
    {
        #region private members

        private Guid? id;
        private int repeatIndicator;        
        private int reserved;
        private int sog;
        private int accuracy;
        private int longitude;
        private int latitude;
        private int cog;
        private int trueHeading;
        private int utcTimestampSecs;
        private DateTime timestamp;
        private int reservedRegional;
        private int spare;
        private int assignedModeFlag;
        private int raimFlag;
        private int commStateSelectedFlag;
        private int commState;

        private static ILog _log = LogManager.GetLogger(typeof(AIS_ClassB));

        #endregion

        #region Properties

        public Guid Id { get { if (!this.id.HasValue) this.id = Guid.NewGuid(); return this.id.Value; } }

        public int Accuracy { get { return accuracy; } }

        public int CogVal { get { return this.cog; } }
        public int SogVal { get { return this.sog; } }
        public int LatitudeVal { get { return this.latitude; } }
        public int LongitudeVal { get { return this.longitude; } }

        public string DBTimestamp
        {
            get
            {
                return this.timestamp.ToString("yyyy-MM-ddTHH:mm:ss.000Z");                
            }
        }       

        public double Cog
        {
            get { return this.cog / 10.0f; }
        }

        public double Sog
        {
            get { return this.sog / 10.0f; }
        }

        public double Latitude
        {
            get { return this.latitude / 600000.0f; }
        }

        public double Longitude
        {
            get { return this.longitude / 600000.0f; }
        }

        public DateTime Timestamp
        {
            get { return this.timestamp; }
        }

        public int? TrueHeading
        {
            get
            {
                if (this.trueHeading == 511) return null;
                return this.trueHeading;
            }
        }

        public int Reserved
        {
            get { return reserved; }
        }

        public int Spare
        {
            get { return this.spare; }
        }

        public int Raim
        {
            get { return this.raimFlag; }
        }

        public int CommState
        {
            get { return this.commState; }
        }

        #endregion

        #region abstract method implementation

        protected override Status Decode()
        {
            BitArray bits = DecodeBinary(this._data);
            Status result = Status.OK;

            try
            {
                int type = GetInt(bits, 0, 5);
                if (type != 18)
                {
                    result = Status.ILLEGAL_ARGUMENT;
                }
                else
                {
                    this.repeatIndicator = GetInt(bits, 6, 7);
                    this._mmsi = GetInt(bits, 8, 37);
                    this.reserved = GetInt(bits, 38, 45);
                    this.sog = GetInt(bits, 46, 55);
                    this.accuracy = GetInt(bits, 56, 56);
                    this.longitude = GetInt(bits, 57, 84);
                    this.latitude = GetInt(bits, 85, 111);
                    this.cog = GetInt(bits, 112, 123);
                    this.trueHeading = GetInt(bits, 124, 132);
                    this.utcTimestampSecs = GetInt(bits, 133,138);
                    this.timestamp = DateTime.Now;
                    this.reservedRegional = GetInt(bits, 139, 140);
                    this.spare = GetInt(bits, 141, 145);
                    this.assignedModeFlag = GetInt(bits, 146, 146);
                    this.raimFlag = GetInt(bits, 147, 147);
                    this.commStateSelectedFlag = GetInt(bits, 148, 148);
                    this.commState = GetInt(bits, 149, 167);
                }
            }
            catch (Exception e)
            {
                _log.WarnFormat("Error decoding AIS class B posreport: {0}", e.Message);
                result = Status.PARSE_ERROR;
            }

            return result;
        }

        #endregion

    }
}