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From: Duncan Sands <baldrick@free.fr>
To: comp.lang.ada@ada-france.org
Cc: Matthew Heaney <matthewjheaney@earthlink.net>
Subject: Re: Hashing on System.Address
Date: Tue, 14 Jun 2005 09:27:33 +0200
Date: 2005-06-14T09:27:33+02:00	[thread overview]
Message-ID: <mailman.23.1118734073.17633.comp.lang.ada@ada-france.org> (raw)
In-Reply-To: <u8y1dllt8.fsf@earthlink.net>

> Good idea.  The other thing I haven't really figured out is what to do
> if you have a 64-bit address, and Hash_Type is only 32.  Ideally you'd
> like to compute a 32-bit hash value that uses all 64 bits of the
> address.

Yes, that's the problem.  In fact to be portable the code should work
regardless of which type has the bigger modulus.

> Alternatively, you could use the ordered container, since type
> System.Address has a less than ("<") relational operator.

I considered that, but since I'm sure to want to hash on addresses one
day, it seemed like a good idea to bite the bullet and come up with a
good solution now.

By the way, is there any reason why Ada.Containers doesn't provide some
standard hash functions?  I reckon hashing on strings and on addresses
would be pretty handy.

Ciao,

Duncan.



  reply	other threads:[~2005-06-14  7:27 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-06-13 20:18 Hashing on System.Address Duncan Sands
2005-06-13 21:31 ` Mark Lorenzen
2005-06-14  7:23   ` Duncan Sands
2005-06-14 20:18     ` Randy Brukardt
2005-06-15  7:27       ` Duncan Sands
2005-06-13 21:57 ` Matthew Heaney
2005-06-13 23:41   ` Robert A Duff
2005-06-14  2:22     ` Matthew Heaney
2005-06-14  7:27       ` Duncan Sands [this message]
2005-06-14  8:52         ` Alex R. Mosteo
2005-06-14  9:06           ` Duncan Sands
2005-06-14  9:09           ` Duncan Sands
2005-06-14 17:00             ` Pascal Obry
2005-06-14 20:03             ` Randy Brukardt
2005-06-14 23:20               ` Robert A Duff
2005-06-15  7:13               ` Duncan Sands
2005-06-14  8:44       ` Larry Kilgallen
2005-06-14 10:03       ` Marius Amado Alves
     [not found]       ` <abb2a2c53e3708803aa68bb87834b7bc@netcabo.pt>
2005-06-14 10:14         ` Duncan Sands
     [not found]         ` <200506141214.14213.baldrick@free.fr>
2005-06-14 10:29           ` Marius Amado Alves
     [not found]           ` <64f19b6707e4d19f5362900bbfb80b76@netcabo.pt>
2005-06-14 10:49             ` Marius Amado Alves
2005-06-14  8:42     ` Larry Kilgallen
2005-06-14 11:18     ` Duncan Sands
2005-06-14  7:18   ` Duncan Sands
2005-06-14 15:18     ` Matthew Heaney
2005-06-14 16:22       ` Duncan Sands
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