Re: Reversing the order of a spoolfile so it prints "backwards"

[Scott Klement <midrange-l@xxxxxxxxxxxxxxxx>]

> I have an application that creates spoolfiles that contains logical
> pages of our bills.   I'm looking for a utility or slick way of
> "reversing" the logical bill pages so they print out in reverse order.
> Anyone got any ideas?

I know of a way that should theoretically work -- and I'm pretty confident 
that I could make it work if I wanted to -- but it'll be really 
complicated, especially if you're not extremely familiar with APIs in 
general, the spooled file APIs in particular.

Here's what I'd do:

a) Dump the spooled file to a user space.
b) Create a new (empty) user space.
c) Find the spooled data for the header, and copy it across.
d) Find the spooled data for the last page, and copy it to the first page 
of the new user space.
e) Keep doing that for the rest of the pages.
f) Copy any footer information
g) Create a new spooled file from the new user space data.

QUSRTOOL has a utility for forcing only certain page ranges to be sent to 
printers.  It uses a similar technique of finding where the pages 
start/end in the spooled file and only sending the ones that match the 
page range.  Of course, it doesn't reverse them, you'd have to write your 
own code to do this, but the QUSRTOOL example might help you get started.

Alternately, if this is an SCS spooled file you could try this instead:

a) Dump the spooled file to a PF with CPYSPLF, use *FCFC control chars.

b) write an HLL program to scan the FCFC chars to determine where pages 
start/stop and use those indications to write out a new PF with the pages 
reversed.

c) Copy the PF back to a spooled file using CPYF and an override to 
specify *FCFC.

That would be much simpler than the API/USRSPC approach, but wouldn't work 
with AFP or IPDS files, they'd have to be plain SCS.

If the spooled file is *USERASCII, I think you're out of luck :)