Hi,
I have a difficult request from a programmer and I'm not sure about the answer.
They have a flat file which has fields that can occur multiple times within
a record, and there are multiple of those fields in the same record. They
want to be able to use DFSORT to overlay (some of) those fields with
specific data, but the offsets change based on how many occurrences of the
recurring fields there are in each record.
We have no problem if we code the offsets manually, but there are files that
have 15 (or more) of these fields and the number of manually coded "WHEN
IFHTEN=" and "overlay=" cards gets into the several thousands when you have
10 to 20 occurrences of each field.
Is there a way to do this with the sort parm logic? I know that the parms
for DFSORT are pretty sophisticated, but the manual isn't written like I
would hope it should be to make it easy to find something like this out.
for instance if there is a file that is set up as follows:
2abcdef1ab3abc
field1o (occurrences of field 1) starts in column1 and is a '2' so there are
two of them in the field (each is 3 bytes long) so "abc,def"
field2o (occurrences of field 2) starts in column 8 in this particular
record and is a '1' so there is only one occurrence of the field2's and it
happens to be 2 bytes long so it's "ab'
field30 (occurrences of field 3) starts in column 11 in this sample and is a
'3' so there are 3 of them, each is 1 byte long so it's "a,b,c"
the problem is that if there is only 1 field1 (instead of 2 in this sample),
then field 2 (because field 1 is 3 bytes long), only occurs one time but
field 2 now starts in column 5 instead of 8, and field3o starts in column 8
instead of 11 and field3 itself starts in column 9.
i.e.
1abc1ab3abc
there will always be at least 1 occurrence of each field, so the minimum is
'1' in each "occurrence" field
I know that we can multiply with the sort logic, but after we multiply the
first occurrence field times the length of field1 (2x3=6), plus the offset
past the first occurrence field 6+1=7, "7" is the last byte of field 1, so
the total length+offset+1=8 which puts me on the next field (filed3o,
occurrences of field 3) that I have to do something with.
My problem is that I don't know that actual offset until execution time via
the math, but I don't know of a way to hold that interim number so that I
can use it in the next calculation (the one for field2o) and then the next
one after that for field3o.
Is there a way to do that, if so, what would an example look like?
thanks for any help you can give, this one is driving me nuts,
Brian
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