[PATCH ] Enhanced DBM Filters

The enclosed patch builds on the changes to DBM Filters applied in #21981.
It enhances the existing DBM Filters to make it easier to create and apply
them. I've created a small all-perl module, called DBM_Filter, to do all the
hard work.

The module includes a number of canned filters for the common filter tasks
needed when interacting with DBM files. In particular, it has two filters
for dealing with encoding, which, for those with long memories, was the
thing that kicked off my reworking of the DBM filter interface.

cheers
Paul

• [PATCH ] Enhanced DBM Filters by Paul Marquess