MimeKit.MimeMessage.GetSignedDkimSignatureHeader C# (CSharp) Method

		static Header GetSignedDkimSignatureHeader (Header dkimSignature)
		{
			// modify the raw DKIM-Signature header value by chopping off the signature value after the "b="
			var rawValue = (byte[]) dkimSignature.RawValue.Clone ();
			int length = 0, index = 0;

			do {
				while (index < rawValue.Length && rawValue[index].IsWhitespace ())
					index++;

				if (index + 2 < rawValue.Length) {
					var param = (char) rawValue[index++];

					while (index < rawValue.Length && rawValue[index].IsWhitespace ())
						index++;

					if (index < rawValue.Length && rawValue[index] == (byte) '=' && param == 'b') {
						length = ++index;

						while (index < rawValue.Length && rawValue[index] != (byte) ';')
							index++;

						if (index == rawValue.Length && rawValue[index - 1] == (byte) '\n') {
							index--;

							if (rawValue[index - 1] == (byte) '\r')
								index--;
						}

						break;
					}
				}

				while (index < rawValue.Length && rawValue[index] != (byte) ';')
					index++;

				if (index < rawValue.Length)
					index++;
			} while (index < rawValue.Length);

			if (index == rawValue.Length)
				throw new FormatException ("Malformed DKIM-Signature header: missing signature parameter.");

			while (index < rawValue.Length)
				rawValue[length++] = rawValue[index++];

			Array.Resize (ref rawValue, length);

			return new Header (dkimSignature.Options, dkimSignature.RawField, rawValue);
		}