using System;
using System.Text;
using Microsoft.SPOT;

namespace CPF
{
    class NMEA_String : ByteString
    {
        private const byte              _asterisk       = 0x2A;
        private const byte              _comma          = 0x2E;
        private readonly byte[]         _hexDigits      = System.Text.Encoding.UTF8.GetBytes("0123456789ABCDEF");

        public void Append(double value)
        {
            Append(_comma);
        }

        public void Append(int value)
        {
            Append(_comma);
        }

        public new void Append(byte[] value, int length)
        {
            Append(_comma);
        }

        public new void Append(string s)
        {
            Append(_comma);
        }

        public void Checksum()
        {
            Append(_asterisk);
            byte checksum = 0;
            for (int i = _head; i < _tail; i++)
                checksum ^= _internalBuffer[i];
            Append(_hexDigits[checksum >> 4]);
            Append(_hexDigits[checksum & 0xF]);
        }
    }
}