OpenISO8583.Net BCD fix format unpack error - openiso8583.net

Question

I downloaded the code from code.google and get the last version v0.5.2
I set a field in bcd fix format,which is N-6 in bcd format(bit._003_proc_code)
For ex:
*Field definition：
DefaultTemplate =new Template
{
{ Bit._002_PAN, FieldDescriptor.BcdVar(2, 19,Formatters.Ascii) },
{ Bit._003_PROC_CODE, FieldDescriptor.BcdFixed(3)},
{ Bit._004_TRAN_AMOUNT, FieldDescriptor.BcdFixed(6) },
..............
}
usage:
Iso8583 msg =new Iso8584();
msg[3]="000000";
when i unpack the message ,i can only get “0000” from message 3 .
is this a bug or error in definition

Answer 1

I would wait to hear from John Oxley to see if this is just a coding error. Now that I said that, I think it is a bug.
I had problems with the BcdFixed definition and ended up creating a new Fixed Length BCD formatter to work around the problem.
Here is what I did:
I created a class called FixedLengthBcdFormatter which is a variation of the FixedLengthFormatter class.
///
/// Fixed field formatter
///
public class FixedLengthBcdFormatter : ILengthFormatter
{
private readonly int _packedLength;
private readonly int _unPackedLength;
///<summary>
/// Fixed length field formatter
///</summary>
///<param name = "unPackedLength">The unpacked length of the field.</param>
public FixedLengthBcdFormatter(int unPackedLength)
{
_unPackedLength = unPackedLength;
double len = _unPackedLength;
_packedLength = (int)Math.Ceiling(len / 2);
}
#region ILengthFormatter Members
/// <summary>
/// Get the length of the packed length indicator. For fixed length fields this is 0
/// </summary>
public int LengthOfLengthIndicator
{
get { return 0; }
}
/// <summary>
/// The maximum length of the field displayed as a string for descriptors
/// </summary>
public string MaxLength
{
get { return _unPackedLength.ToString(); }
}
/// <summary>
/// Descriptor for the length formatter used in ToString methods
/// </summary>
public string Description
{
get { return "FixedBcd"; }
}
/// <summary>
/// Get the length of the field
/// </summary>
/// <param name = "msg">Byte array of message data</param>
/// <param name = "offset">offset to start parsing</param>
/// <returns>The length of the field</returns>
public int GetLengthOfField(byte[] msg, int offset)
{
return _unPackedLength;
}
/// <summary>
/// Pack the length header into the message
/// </summary>
/// <param name = "msg">Byte array of the message</param>
/// <param name = "length">The length to pack into the message</param>
/// <param name = "offset">Offset to start the packing</param>
/// <returns>offset for the start of the field</returns>
public int Pack(byte[] msg, int length, int offset)
{
return offset;
}
/// <summary>
/// Check the length of the field is valid
/// </summary>
/// <param name = "packedLength">the packed length of the field</param>
/// <returns>true if valid, false otherwise</returns>
public bool IsValidLength(int packedLength)
{
return packedLength == _packedLength;
}
#endregion
}
Modified the FieldDescription class / BcdFixed declaration
///
/// The bcd fixed.
///
///
/// The length.
///
///
///
public static IFieldDescriptor BcdFixed(int unpackedLength)
{
return Create(new FixedLengthBcdFormatter(unpackedLength), FieldValidators.N, Formatters.Bcd, null);
}
Then change your formatter declaration to provide the unpacked length as the paramter.
Bit._003_PROC_CODE, FieldDescriptor.BcdFixed(6)},
Again, all this may have been unnecessary because I didn't know something about the existing code, but it is working for me.
I hope this helps.