public override int BerEncode(IAsn1BerEncodingBuffer buffer, bool explicitTag = true)
{
int length = ValueBerEncode(buffer);
length += LengthBerEncode(buffer, length);
buffer.WriteByte(101);
buffer.WriteByte(127);
return(length + 2);
}
/// <summary>
/// Encodes the data of this object to the buffer.
/// </summary>
/// <param name="buffer">A buffer to which the encoding result will be written.</param>
/// <returns>The length of the encoding result of the data.</returns>
/// <remarks>
/// For the TLV (Tag, Length, Value) triple in the encoding result,
/// this method provides the functionality of encoding Value.
/// The encoding for Tag and Length will be done in Asn1Object::BerEncode method.
/// </remarks>
protected override int ValueBerEncode(IAsn1BerEncodingBuffer buffer)
{
//Encode data
if (Value == false)
{
buffer.WriteByte(0);
}
else
{
buffer.WriteByte(255);
}
return(1);
}
/// <summary>
/// Encodes the data of this object to the buffer.
/// </summary>
/// <param name="buffer">A buffer to which the encoding result will be written.</param>
/// <returns>The length of the encoding result of the data.</returns>
/// <remarks>
/// For the TLV (Tag, Length, Value) triple in the encoding result,
/// this method provides the functionality of encoding Value.
/// The encoding for Tag and Length will be done in Asn1Object::BerEncode method.
/// </remarks>
protected override int ValueBerEncode(IAsn1BerEncodingBuffer buffer)
{
//Ref. X.680: 8.6.2.2
buffer.WriteBytes(ByteArrayValue);
buffer.WriteByte(unusedBitsInLastByte);
return(ByteArrayValue.Length + 1);
}
/// <summary>
/// Encodes a length to the buffer.
/// </summary>
/// <param name="buffer"></param>
/// <param name="length">The length to be written to the buffer.</param>
/// <returns>The length of "the encoded length's encoding result".</returns>
public static int LengthBerEncode(IAsn1BerEncodingBuffer buffer, int length)
{
if (length < 0)
{
throw new Asn1InvalidArgument(ExceptionMessages.LengthNegative);
}
if (length < 128)
{
buffer.WriteByte((byte)length);
return(1);
}
else
{
//The encoding result of a length that no less than 128 will be stored in at least two bytes.
//The first byte: 1xxxxxxx, xxxxxxx is the length of the following encoding result.
//The next bytes: the length's encoding result, big endian.
//Ref. X.690: 8.1.3
byte[] bytes = BitConverter.GetBytes(length);
//ensure bytes is big endian
if (BitConverter.IsLittleEndian)
{
Array.Reverse(bytes);
}
//delete the redundant zeros
int zeroNum = 0;
for (int i = 0; i < bytes.Length; i++)
{
if (bytes[i] == 0)
{
zeroNum++;
}
else
{
break;
}
}
//zeroNum won't be equal to bytes.Length since length>=128.
//Encode data first, then encode length of the data's encoding result since buffer is reversed.
buffer.WriteBytes(bytes, zeroNum, bytes.Length - zeroNum);
buffer.WriteByte((byte)((bytes.Length - zeroNum) | (1 << 7)));//set the first bit to 1
return(1 + bytes.Length - zeroNum);
}
}
/// <summary>
/// Encodes a tag to the buffer.
/// </summary>
/// <param name="buffer"></param>
/// <param name="tag"></param>
/// <returns>The length of the encoding result.</returns>
public static int TagBerEncode(IAsn1BerEncodingBuffer buffer, Asn1Tag tag)
{
//Ref. X.690: 8.1.2.2, there are four kinds of tags
byte prefix = 0;
switch (tag.TagType)
{
case Asn1TagType.Universal:
{
prefix = 0; //00
} break;
case Asn1TagType.Application:
{
prefix = 1; //01
} break;
case Asn1TagType.Context:
{
prefix = 2; //10
} break;
case Asn1TagType.Private:
{
prefix = 3; //11
//Ref. X.680: G.2.12.4
throw new Asn1UnreachableExcpetion(ExceptionMessages.Unreachable);
};
}
prefix <<= 6;
if (tag.EncodingWay == EncodingWay.Constructed)
{
prefix |= (1 << 5); //Set the sixth bit to 1 if it is encoded in constructed way. Ref. X.690: 8.1.2.3
}
if (tag.TagValue <= 30) //Use one byte to store the encoding result
//Ref. X.690: 8.1.2.3
{
prefix |= (byte)tag.TagValue;
buffer.WriteByte(prefix);
return(1);
}
else//Use more than one bytes to store.
{
//Ref. X.690: 8.1.2.4.3
throw new NotImplementedException("Case tag > 30 is not implemented. Check X.690: 8.1.2.4.3.");
}
}
/// <summary>
/// Encodes a length to the buffer.
/// </summary>
/// <param name="buffer"></param>
/// <param name="length">The length to be written to the buffer.</param>
/// <returns>The length of "the encoded length's encoding result".</returns>
public static int LengthBerEncode(IAsn1BerEncodingBuffer buffer, int length)
{
if (length < 0)
{
throw new Asn1InvalidArgument(ExceptionMessages.LengthNegative);
}
if (length < 128)
{
buffer.WriteByte((byte)length);
return 1;
}
else
{
//The encoding result of a length that no less than 128 will be stored in at least two bytes.
//The first byte: 1xxxxxxx, xxxxxxx is the length of the following encoding result.
//The next bytes: the length's encoding result, big endian.
//Ref. X.690: 8.1.3
byte[] bytes = BitConverter.GetBytes(length);
//ensure bytes is big endian
if (BitConverter.IsLittleEndian)
{
Array.Reverse(bytes);
}
//delete the redundant zeros
int zeroNum = 0;
for (int i = 0; i < bytes.Length; i++)
{
if (bytes[i] == 0)
{
zeroNum++;
}
else
{
break;
}
}
//zeroNum won't be equal to bytes.Length since length>=128.
//Encode data first, then encode length of the data's encoding result since buffer is reversed.
buffer.WriteBytes(bytes, zeroNum, bytes.Length - zeroNum);
buffer.WriteByte((byte)((bytes.Length - zeroNum) | (1 << 7)));//set the first bit to 1
return 1 + bytes.Length - zeroNum;
}
}
/// <summary>
/// Encodes the data of this object to the buffer.
/// </summary>
/// <param name="buffer">A buffer to which the encoding result will be written.</param>
/// <returns>The length of the encoding result of the data.</returns>
/// <remarks>
/// For the TLV (Tag, Length, Value) triple in the encoding result,
/// this method provides the functionality of encoding Value.
/// The encoding for Tag and Length will be done in Asn1Object::BerEncode method.
/// </remarks>
protected override int ValueBerEncode(IAsn1BerEncodingBuffer buffer)
{
//Encode data
if (Value == false)
{
buffer.WriteByte(0);
}
else
{
buffer.WriteByte(255);
}
return 1;
}
/// <summary>
/// Encodes a tag to the buffer.
/// </summary>
/// <param name="buffer"></param>
/// <param name="tag"></param>
/// <returns>The length of the encoding result.</returns>
public static int TagBerEncode(IAsn1BerEncodingBuffer buffer, Asn1Tag tag)
{
//Ref. X.690: 8.1.2.2, there are four kinds of tags
byte prefix = 0;
switch (tag.TagType)
{
case Asn1TagType.Universal:
{
prefix = 0;//00
} break;
case Asn1TagType.Application:
{
prefix = 1;//01
} break;
case Asn1TagType.Context:
{
prefix = 2;//10
} break;
case Asn1TagType.Private:
{
prefix = 3;//11
//Ref. X.680: G.2.12.4
throw new Asn1UnreachableExcpetion(ExceptionMessages.Unreachable);
};
}
prefix <<= 6;
if (tag.EncodingWay == EncodingWay.Constructed)
{
prefix |= (1 << 5);//Set the sixth bit to 1 if it is encoded in constructed way. Ref. X.690: 8.1.2.3
}
if (tag.TagValue <= 30)//Use one byte to store the encoding result
//Ref. X.690: 8.1.2.3
{
prefix |= (byte)tag.TagValue;
buffer.WriteByte(prefix);
return 1;
}
else//Use more than one bytes to store.
{
//Ref. X.690: 8.1.2.4.3
throw new NotImplementedException("Case tag > 30 is not implemented. Check X.690: 8.1.2.4.3.");
}
}
public override int BerEncode(IAsn1BerEncodingBuffer buffer, bool explicitTag = true)
{
int length = ValueBerEncode(buffer);
length += LengthBerEncode(buffer, length);
buffer.WriteByte(101);
buffer.WriteByte(127);
return length + 2;
}
/// <summary>
/// Encodes the data of this object to the buffer.
/// </summary>
/// <param name="buffer">A buffer to which the encoding result will be written.</param>
/// <returns>The length of the encoding result of the data.</returns>
/// <remarks>
/// For the TLV (Tag, Length, Value) triple in the encoding result,
/// this method provides the functionality of encoding Value.
/// The encoding for Tag and Length will be done in Asn1Object::BerEncode method.
/// </remarks>
protected override int ValueBerEncode(IAsn1BerEncodingBuffer buffer)
{
//Ref. X.680: 8.6.2.2
buffer.WriteBytes(ByteArrayValue);
buffer.WriteByte(unusedBitsInLastByte);
return ByteArrayValue.Length + 1;
}
