Re: [Quickfix-developers] Howto specify explicitly order of custom fields?

[Oren M. <or...@qu...>]

Well, if you dig down into the C++ layer, in the FieldMap class, you =20
will notice that a FieldMap constructor takes a message_order =20
object.  Now, if you look in MessageSorters.h, you will find the =20
message_order object which has 4 modes.

header: Makes sure that the BeginString, BodyLength, and MsgType are =20
the first three fields.  Everything else in ascending numerical order.

trailer: Makes sure the CheckSum field is last.  Everything else in =20
ascending numerical order.

normal: Sorted in ascending numerical order, used for message body's

group: Sorted in the order based on provided list.

Why is it like this?  Well sorting things in ascending order is just =20
the simplest fastest way to sort fields and complies with the spec.  =20
The group order was introduced because the spec explicitly states =20
that repeating groups must be in a specific order.

Basically to accomplish what you need would require some new =20
functionality.  I think it would require the implementation of a data =20=

dictionary sorting mode.

--oren

On Jul 15, 2005, at 11:27 AM, Joerg Thoennes wrote:

> Hi Oren,
>
>
>> Which fields need to be ordered?  The custom tags in the header =20
>> and  the trailer?  The entire message?
>>
>
> To be more precise: EMX adds extra custom fields to both the header =20=

> and trailer, and of course to the body.
>
> We generated the new QF classes using the XML scripts, but the =20
> order seems to be different from what EMX expects.
>
> So our questions is:
>
> How can we control the order of tags in
>
> (a) header
> (b) body
> (c) trailer
>
> My guess is that the DD order controls at least the body order, but =20=

> I am not sure about header and trailer. After some digging of the =20
> source code some advise from you would be very helpful.
>
> Thanks, J=F6rg
>
> --=20
> Joerg Thoennes
>                                http://macd.com
> Tel.: +49 (0)241 44597-24      Macdonald Associates GmbH
> Fax : +49 (0)241 44597-10      Lothringer Str. 52, D-52070 Aachen
>
>