SpecifiedECDomain.cs

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using System.Formats.Asn1;
 
namespace System.Security.Cryptography.Asn1;
 
internal struct SpecifiedECDomain
{
    internal int Version;
 
    internal System.Security.Cryptography.Asn1.FieldID FieldID;
 
    internal System.Security.Cryptography.Asn1.CurveAsn Curve;
 
    internal ReadOnlyMemory<byte> Base;
 
    internal ReadOnlyMemory<byte> Order;
 
    internal ReadOnlyMemory<byte>? Cofactor;
 
    internal string Hash;
 
    internal void Encode(AsnWriter writer)
    {
        Encode(writer, Asn1Tag.Sequence);
    }
 
    internal void Encode(AsnWriter writer, Asn1Tag tag)
    {
        writer.PushSequence(tag);
        writer.WriteInteger((long)Version, (Asn1Tag?)null);
        FieldID.Encode(writer);
        Curve.Encode(writer);
        writer.WriteOctetString(Base.Span);
        writer.WriteInteger(Order.Span);
        if (Cofactor.HasValue)
        {
            writer.WriteInteger(Cofactor.Value.Span);
        }
        if (Hash != null)
        {
            try
            {
                writer.WriteObjectIdentifier(Hash);
            }
            catch (ArgumentException inner)
            {
                throw new CryptographicException(System.SR.Cryptography_Der_Invalid_Encoding, inner);
            }
        }
        writer.PopSequence(tag);
    }
 
    internal static void Decode(ref System.Formats.Asn1.AsnValueReader reader, ReadOnlyMemory<byte> rebind, out System.Security.Cryptography.Asn1.SpecifiedECDomain decoded)
    {
        Decode(ref reader, Asn1Tag.Sequence, rebind, out decoded);
    }
 
    internal static void Decode(ref System.Formats.Asn1.AsnValueReader reader, Asn1Tag expectedTag, ReadOnlyMemory<byte> rebind, out System.Security.Cryptography.Asn1.SpecifiedECDomain decoded)
    {
        try
        {
            DecodeCore(ref reader, expectedTag, rebind, out decoded);
        }
        catch (AsnContentException inner)
        {
            throw new CryptographicException(System.SR.Cryptography_Der_Invalid_Encoding, inner);
        }
    }
 
    private static void DecodeCore(ref System.Formats.Asn1.AsnValueReader reader, Asn1Tag expectedTag, ReadOnlyMemory<byte> rebind, out System.Security.Cryptography.Asn1.SpecifiedECDomain decoded)
    {
        decoded = default(System.Security.Cryptography.Asn1.SpecifiedECDomain);
        System.Formats.Asn1.AsnValueReader reader2 = reader.ReadSequence(expectedTag);
        ReadOnlySpan<byte> span = rebind.Span;
        if (!reader2.TryReadInt32(out decoded.Version))
        {
            reader2.ThrowIfNotEmpty();
        }
        System.Security.Cryptography.Asn1.FieldID.Decode(ref reader2, rebind, out decoded.FieldID);
        System.Security.Cryptography.Asn1.CurveAsn.Decode(ref reader2, rebind, out decoded.Curve);
        int elementOffset;
        if (reader2.TryReadPrimitiveOctetString(out var value))
        {
            decoded.Base = (span.Overlaps(value, out elementOffset) ? rebind.Slice(elementOffset, value.Length) : ((ReadOnlyMemory<byte>)value.ToArray()));
        }
        else
        {
            decoded.Base = reader2.ReadOctetString();
        }
        value = reader2.ReadIntegerBytes();
        decoded.Order = (span.Overlaps(value, out elementOffset) ? rebind.Slice(elementOffset, value.Length) : ((ReadOnlyMemory<byte>)value.ToArray()));
        if (reader2.HasData && reader2.PeekTag().HasSameClassAndValue(Asn1Tag.Integer))
        {
            value = reader2.ReadIntegerBytes();
            decoded.Cofactor = (span.Overlaps(value, out elementOffset) ? rebind.Slice(elementOffset, value.Length) : ((ReadOnlyMemory<byte>)value.ToArray()));
        }
        if (reader2.HasData && reader2.PeekTag().HasSameClassAndValue(Asn1Tag.ObjectIdentifier))
        {
            decoded.Hash = reader2.ReadObjectIdentifier();
        }
        reader2.ThrowIfNotEmpty();
    }
}