protected virtual TypeConstructor FindTypeConstructor(DerAsnIdentifier identifier)
{
if (_registeredClassSpecificTypes.TryGetValue(identifier, out var classSpecificTypeConstructor))
{
return(classSpecificTypeConstructor);
}
var typeKey = new TypeKey {
EncodingType = identifier.EncodingType, Tag = identifier.Tag
};
if (_registeredTypes.TryGetValue(typeKey, out classSpecificTypeConstructor))
{
return(classSpecificTypeConstructor);
}
return(null);
}
/// <summary>
/// Decode a single ASN.1 type encoded in the given byte queue.
/// </summary>
/// <param name="data">The data.</param>
/// <returns>The decoded ASN.1 type (primitive or constructed set/sequence).</returns>
public DerAsnType Decode(Queue <byte> data)
{
var identifier = DerAsnIdentifier.Decode(data);
var typeConstructor = FindTypeConstructor(identifier)
?? throw new InvalidOperationException($"No type registered for identifier {identifier}");
var length = DerAsnLength.Decode(data);
if (data.Count < length)
{
throw new InvalidOperationException($"Expected {length} bytes to decode type with identifier {identifier} but got {data.Count} bytes");
}
var dataForType = new Queue <byte>(data.Dequeue(length.Length));
return(typeConstructor(this, identifier, dataForType));
}
/// <summary>
/// Registers a class dependent type.
/// </summary>
/// <param name="identifier">The exact tag identifier of the type.</param>
/// <param name="typeConstructor">The type constructor.</param>
/// <param name="replace">True to allow replacing an existing registration, otherwise false</param>
/// <returns>The <see cref="DefaultDerAsnDecoder"/> instance.</returns>
public DefaultDerAsnDecoder RegisterType(DerAsnIdentifier identifier, TypeConstructor typeConstructor, bool replace = false)
{
if (identifier == null)
{
throw new ArgumentNullException(nameof(identifier));
}
if (typeConstructor == null)
{
throw new ArgumentNullException(nameof(typeConstructor));
}
if (!replace && _registeredClassSpecificTypes.ContainsKey(identifier))
{
throw new InvalidOperationException($"Type with class {identifier.TagClass}, encoding type {identifier.EncodingType} and tag number {identifier.Tag} already registered");
}
_registeredClassSpecificTypes[identifier] = typeConstructor;
return(this);
}
protected DerAsnType(DerAsnIdentifier identifier)
{
Identifier = identifier;
}
