[Devel] New cache sub-system implementation

[David Turner]

Hello,

  I have commited a new implementation of the cache sub-system to
the FreeType CVS repository. This is a complete re-design that
fortunately shouldn't break source or binary compatibility, as long
as you're using the functions documented in the official FT2 API.

  The purpose of these changes were to:

    A - improve performance

    B - simplify the development of custom caches

    C - provide an "acquire/release" interface to each
        cache node in order to "lock" certain nodes in order
        to prevent them from being flushed from the pool.
        this required the introduction of a reference count
        in each cache node..

  I have not tested A yet, but it seems to work at least as well
  as the original code, and a few optimizations are still possible.

  I have succeeded in B though I suspect that I'll introduce a few
  more simplifications in the very near future to make things even
  eaiser to use..

  And C is really a great feature to have :-)

  See also the document at:
 
    http://www.freetype.org/freetype2/docs/cache.html

  that describes the cache sub-system design, how to use it,
  and even how to create a few custom caches..


Regards,

- David