init commit

output/Libraries/BouncyCastle.Crypto/Org/BouncyCastle/Bcpg/SignatureSubpacketsParser.cs

@@ -0,0 +1,104 @@
+using System.IO;
+using Org.BouncyCastle.Bcpg.Sig;
+using Org.BouncyCastle.Utilities;
+using Org.BouncyCastle.Utilities.IO;
+
+namespace Org.BouncyCastle.Bcpg;
+
+public class SignatureSubpacketsParser
+{
+	private readonly Stream input;
+
+	public SignatureSubpacketsParser(Stream input)
+	{
+		this.input = input;
+	}
+
+	public SignatureSubpacket ReadPacket()
+	{
+		int num = input.ReadByte();
+		if (num < 0)
+		{
+			return null;
+		}
+		int num2 = 0;
+		bool isLongLength = false;
+		if (num < 192)
+		{
+			num2 = num;
+		}
+		else if (num <= 223)
+		{
+			num2 = (num - 192 << 8) + input.ReadByte() + 192;
+		}
+		else
+		{
+			if (num != 255)
+			{
+				throw new IOException("unexpected length header");
+			}
+			isLongLength = true;
+			num2 = (input.ReadByte() << 24) | (input.ReadByte() << 16) | (input.ReadByte() << 8) | input.ReadByte();
+		}
+		int num3 = input.ReadByte();
+		if (num3 < 0)
+		{
+			throw new EndOfStreamException("unexpected EOF reading signature sub packet");
+		}
+		byte[] array = new byte[num2 - 1];
+		int num4 = Streams.ReadFully(input, array);
+		bool critical = (num3 & 0x80) != 0;
+		SignatureSubpacketTag signatureSubpacketTag = (SignatureSubpacketTag)(num3 & 0x7F);
+		if (num4 != array.Length)
+		{
+			array = signatureSubpacketTag switch
+			{
+				SignatureSubpacketTag.CreationTime => CheckData(array, 4, num4, "Signature Creation Time"), 
+				SignatureSubpacketTag.IssuerKeyId => CheckData(array, 8, num4, "Issuer"), 
+				SignatureSubpacketTag.KeyExpireTime => CheckData(array, 4, num4, "Signature Key Expiration Time"), 
+				SignatureSubpacketTag.ExpireTime => CheckData(array, 4, num4, "Signature Expiration Time"), 
+				_ => throw new EndOfStreamException("truncated subpacket data."), 
+			};
+		}
+		switch (signatureSubpacketTag)
+		{
+		case SignatureSubpacketTag.CreationTime:
+			return new SignatureCreationTime(critical, isLongLength, array);
+		case SignatureSubpacketTag.KeyExpireTime:
+			return new KeyExpirationTime(critical, isLongLength, array);
+		case SignatureSubpacketTag.ExpireTime:
+			return new SignatureExpirationTime(critical, isLongLength, array);
+		case SignatureSubpacketTag.Revocable:
+			return new Revocable(critical, isLongLength, array);
+		case SignatureSubpacketTag.Exportable:
+			return new Exportable(critical, isLongLength, array);
+		case SignatureSubpacketTag.IssuerKeyId:
+			return new IssuerKeyId(critical, isLongLength, array);
+		case SignatureSubpacketTag.TrustSig:
+			return new TrustSignature(critical, isLongLength, array);
+		case SignatureSubpacketTag.PreferredSymmetricAlgorithms:
+		case SignatureSubpacketTag.PreferredHashAlgorithms:
+		case SignatureSubpacketTag.PreferredCompressionAlgorithms:
+			return new PreferredAlgorithms(signatureSubpacketTag, critical, isLongLength, array);
+		case SignatureSubpacketTag.KeyFlags:
+			return new KeyFlags(critical, isLongLength, array);
+		case SignatureSubpacketTag.PrimaryUserId:
+			return new PrimaryUserId(critical, isLongLength, array);
+		case SignatureSubpacketTag.SignerUserId:
+			return new SignerUserId(critical, isLongLength, array);
+		case SignatureSubpacketTag.NotationData:
+			return new NotationData(critical, isLongLength, array);
+		default:
+			return new SignatureSubpacket(signatureSubpacketTag, critical, isLongLength, array);
+		}
+	}
+
+	private byte[] CheckData(byte[] data, int expected, int bytesRead, string name)
+	{
+		if (bytesRead != expected)
+		{
+			throw new EndOfStreamException("truncated " + name + " subpacket data.");
+		}
+		return Arrays.CopyOfRange(data, 0, expected);
+	}
+}