[ANNOUNCE] Bindings to Gnu Database Manager

[ANNOUNCE] Bindings to Gnu Database Manager

[Greg Baker]

Currently available at

 ftp://ftp.rp.csiro.au/pub/people/gbaker/gdbm-1-7-3-ada-bindings-alpha.tar.gz

Unfortunately,  I will be leaving CSIRO soon,  and won't be able to
provide an anonymous ftp home for these for very much longer.  If you
would like to provide a home for an 8k tar file, and a 2k README,  I'd
love to hear from you.

Here's the README.

----------------------------------------------------------------------

                 Gdbm Ada-interface README file

What is this thing?

  An interface to the GNU database manager which looks nicely
Ada-like.  Automatically generated interfaces tend to look like C and
makes for funny Ada, making client code somewhat error-prone.  This
interface provides nice wrappers for the gdbm functions allowing
client packages to be kept type-safe and readable.

  My aim has been to make it as readable and as obvious as possible,
rather than to keep similarity with the C versions.  For example,
gdbm_setopt has turned into 
    Gnu.Gdbm.Set_Cache_Size,
    Gnu.Gdbm.Turn_On_Fast_Mode 
    Gnu.Gdbm.Turn_Off_Fast_Mode
which strikes me as somewhat more obvious!


What versions of gdbm does it work with?

  Probably most of them,  since the C interface hasn't changed in a
while.  I developed and tested it under Linux using gdbm-1.7.3.  



What compilers/platforms are supported?

  I really haven't a clue.  It only uses Ada83 constructs,  but I have
only ever compiled it under Linux using Gnat 3.04.  I would guess any
Ada compiler,  any flavour of Unix.  You might get lucky with other
platforms. 



Thread-safe?

  It is as thread safe as gdbm itself,  which (I believe) is not safe
at all.  This doesn't particularly concern me - if you are updating
and reading entries from the database in different threads,  you have
horrible race conditions awaiting you.  If you are just reading,  then
I suggest you open the database multiple times.



How do I use it?

  The best answer to that is to look at gdbm_test.adb - hopefully that
should make it fairly clear what to do.  gnu.gdbm.ads is very nicely
documented - the non-private parts of it should tell you all you need
to know.  Finally,  the man pages that came with gdbm might be of some
assistance as well,  if you want to have fine details.

  A quick summary - instantiate a Database with some Key_Type and
Content_Type.  Open a GDBM_Database.  Using this GDBM_Database you can
      Store
      Fetch
      Delete
      Reorganise
      Sync
      check something Exists
      iterate from First_Key using Next_Key
      Close
      Set_Cache_Size
      Turn_On_Fast_Mode
      Turn_Off_Fast_Mode

  I compile using "gnatmake gdbm_test -largs -lgdbm". Your methods
will (obviously) vary.


What's all this other junk in the distribution?

  It seemed sensible to put the interfaces under a package GNU - I
intend to write other such "nice" bindings in the future.  Similarly,
Unix file modes crop up in lots of different places,  and there is
bound to be more Unix-specific things in the future too.  Consider
this the first in a long line of such things.


Anything else?

  At the moment,  if you do anything that returns a Key_Type or a
Content_Type (i.e.  Fetch,  First_Key, Next_Key),  the wrappers check
to make sure that the size of data it found is the same as the size of
a Key_Type or a Content_Type (whichever is appropriate).  So if you
have extended types (i.e. you are using Ada95's object features) and
you store a child type,  and then later attempt to fetch it when the
Content_Type is a parent,  you will have Data_Invalidity raised,  even
though the child is a valid subclass of parent.  I would appreciate
suggestions as to how to fix this nicely.

  You perhaps also should be warned that this was one of the first
things I have written in Ada.  Hopefully this won't be noticable!


Contacts

  I will only be at CSIRO Radiophysics until the beginning of October,
1996 (gbaker@rp.csiro.au).  After that I will be gregb@apt.net.au, and
might not be as heavily net-connected as I am now.  I fully intend to
support this for as long as people are interested.  (Although I doubt
it will need much support).  If you are reading this sometime a long
time after 1996 I should still be easily findable.  Search for
 - Greg Baker "quantum computers" solresol "probable" - 


GdB,  10-September-1996. Striving for a GNU-ful and Christian world.


 


-- 
Gregory D. Baker        gbaker@rp.csiro.au         CSIRO Radiophysics 
   - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  
   - predictions of the future - quantum computers - silly poetry  -
   - the "langue musicale universale" (Solresol)  revival project  - 
   - - - - - - - - http://www.rp.csiro.au/~gbaker  - - - - - - - - -
I am about to leave CSIRO. The above email address and URL may become
 invalid in October.  Email should then be sent to gregb@apt.net.au.