PssParamsAsn.cs

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using System.Formats.Asn1;
 
namespace System.Security.Cryptography.Asn1;
 
internal struct PssParamsAsn
{
    internal System.Security.Cryptography.Asn1.AlgorithmIdentifierAsn HashAlgorithm;
 
    internal System.Security.Cryptography.Asn1.AlgorithmIdentifierAsn MaskGenAlgorithm;
 
    internal int SaltLength;
 
    internal int TrailerField;
 
    private static ReadOnlySpan<byte> DefaultHashAlgorithm => new byte[11]
    {
        48, 9, 6, 5, 43, 14, 3, 2, 26, 5,
        0
    };
 
    private static ReadOnlySpan<byte> DefaultMaskGenAlgorithm => new byte[24]
    {
        48, 22, 6, 9, 42, 134, 72, 134, 247, 13,
        1, 1, 8, 48, 9, 6, 5, 43, 14, 3,
        2, 26, 5, 0
    };
 
    private static ReadOnlySpan<byte> DefaultSaltLength => new byte[3] { 2, 1, 20 };
 
    private static ReadOnlySpan<byte> DefaultTrailerField => new byte[3] { 2, 1, 1 };
 
    internal void Encode(AsnWriter writer)
    {
        Encode(writer, Asn1Tag.Sequence);
    }
 
    internal void Encode(AsnWriter writer, Asn1Tag tag)
    {
        writer.PushSequence(tag);
        AsnWriter asnWriter = new AsnWriter(AsnEncodingRules.DER);
        HashAlgorithm.Encode(asnWriter);
        if (!asnWriter.EncodedValueEquals(DefaultHashAlgorithm))
        {
            writer.PushSequence(new Asn1Tag(TagClass.ContextSpecific, 0));
            asnWriter.CopyTo(writer);
            writer.PopSequence(new Asn1Tag(TagClass.ContextSpecific, 0));
        }
        AsnWriter asnWriter2 = new AsnWriter(AsnEncodingRules.DER);
        MaskGenAlgorithm.Encode(asnWriter2);
        if (!asnWriter2.EncodedValueEquals(DefaultMaskGenAlgorithm))
        {
            writer.PushSequence(new Asn1Tag(TagClass.ContextSpecific, 1));
            asnWriter2.CopyTo(writer);
            writer.PopSequence(new Asn1Tag(TagClass.ContextSpecific, 1));
        }
        AsnWriter asnWriter3 = new AsnWriter(AsnEncodingRules.DER);
        asnWriter3.WriteInteger(SaltLength);
        if (!asnWriter3.EncodedValueEquals(DefaultSaltLength))
        {
            writer.PushSequence(new Asn1Tag(TagClass.ContextSpecific, 2));
            asnWriter3.CopyTo(writer);
            writer.PopSequence(new Asn1Tag(TagClass.ContextSpecific, 2));
        }
        AsnWriter asnWriter4 = new AsnWriter(AsnEncodingRules.DER);
        asnWriter4.WriteInteger(TrailerField);
        if (!asnWriter4.EncodedValueEquals(DefaultTrailerField))
        {
            writer.PushSequence(new Asn1Tag(TagClass.ContextSpecific, 3));
            asnWriter4.CopyTo(writer);
            writer.PopSequence(new Asn1Tag(TagClass.ContextSpecific, 3));
        }
        writer.PopSequence(tag);
    }
}