using System;

namespace GostCryptography.Asn1.Ber
{
    [Serializable]
    public class Asn1Null : Asn1Type
    {
        public static readonly Asn1Tag Tag = new Asn1Tag(0, 0, NullTypeCode);
        public static readonly Asn1Null NullValue = new Asn1Null();

        public override void Decode(Asn1BerDecodeBuffer buffer, bool explicitTagging, int implicitLength)
        {
            if (explicitTagging)
            {
                MatchTag(buffer, Tag);
            }

            buffer.TypeCode = NullTypeCode;
        }

        public override int Encode(Asn1BerEncodeBuffer buffer, bool explicitTagging)
        {
            var len = 0;

            if (explicitTagging)
            {
                len += buffer.EncodeTagAndLength(Tag, len);
            }

            return len;
        }

        public override void Encode(Asn1BerOutputStream outs, bool explicitTagging)
        {
            if (explicitTagging)
            {
                outs.EncodeTag(Tag);
            }

            outs.EncodeLength(0);
        }

        public override string ToString()
        {
            return "NULL";
        }
    }
}