[This message was posted by Rolf Andersson of Pantor Engineering <[email protected]> to the "FAST Protocol" discussion forum at http://fixprotocol.org/discuss/46. You can reply to it on-line at http://fixprotocol.org/discuss/read/11f54d39 - PLEASE DO NOT REPLY BY MAIL.]
> Rolf, > > Let's say there is a field is optional. operator is tail. field type is > string and no initial value. Then when I recevie 0x80 which means is > null value, how to proceed? > > Here is another case. There is a field is optional and the operator is > constant. If the pmap bit is set, should the value appear in the stream > or just use the default value? > > BTW Can I say that the initial value is used if the field is absent no > matter what operator is? > > Michael > > > that depends on the field definition. type? operators? inital value? > > > > please be more specific > > > > /Rolf > > > > > Rolf, > > > > > > Oh I made a mistake that I think mantissa is optional. so the value > > > is decreased by 1. > > > > > > I want to know how to handle if a field is absent. > > > > > > Michael > > > > > > > > Rolf, > > > > > > > > > > I am sorry I got confused again. For tag 271, the pmap bit is 0. > > > > > so the default value 0 is used for exponent. Can we say that the > > > > > exponent has a value so that we need to decode mantissa? If so, > > > > > the encoded value is 0x82 for the mantissa. The decoded value > > > > > should be 1 since it is delta operator, Right? > > > > > > > > Yes, 0x82 is for the mantissa. No, the decoded mantissa value is > > > > 2. Why do you think the value should be 1? > > > > > > > > > BTW, if the length field of a sequence field is greater than 1, > > > > > does the sequence pmap appear each iteration? > > > > > > > > yes, as noted in my mail below > > > > > > > > (FAST 1.1 spec section 6.2.5 says: "If any instruction of the > > > > group needs to allocate a bit in a presence map, each element is > > > > represented as a segment in the transfer encoding." "element" in > > > > this context is synonymous with my use of "iteration" in my mail > > > > below) > > > > > > > > /Rolf > > > > > > > > ... snip ... > > > > > > > > >> Michael, > > > > >> > > > > >> The pmap entry for the length field is located in the _message_ > > > > >> level pmap (bit 7 in this case). The sequence level pmap occurs > > > > >> for every iteration (repetition) of the sequence and provides > > > > >> presence info for the fields in the current iteration. [You can unsubscribe from this discussion group by sending a message to mailto:[email protected]] --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Financial Information eXchange" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/FIX-Protocol?hl=en -~----------~----~----~----~------~----~------~--~---
