compressed bitvectors for postgresql (and perl, php, etc)

Hello everyone

Although this is not a patch,  I have developped a set of
user-defined function to deal with compressed bitvectors,
which are the same than bit varying but much smaller
since they are compressed.

Since I am in a process to migrate my applications from mysql to postgresql,
they are juste made available for postgresql there :
  http://www.vtech.fr/opensource (hope links are ok here?)

They are designed in such a way that setting or resetting a bit in the
bit array can be done without having to uncompress/recompress the bitvector.
In some cases, they might be faster than bit varying, since bitwise
operations
are dealt with on a block-by-block basis.

They have serious limitations, the main one being that bit-indexes must be
kept
in the range [0-8388599]

I'm glad to give that away to this community, although I humbly am eager to
get
some feedback to realize if this compressed bitvector notion is of any help
to someone else than myself :)

Rgds,
Jean "flynn" Flinois