Date: Sun, 30 Dec 2007 08:35:21 +1100 From: Peter Jeremy <peterjeremy@optushome.com.au> To: "Edward B. DREGER" <eddy+public+spam@noc.everquick.net> Cc: hackers@freebsd.org Subject: Re: BSD license compatible hash algorithm? Message-ID: <20071229213521.GW40785@server.vk2pj.dyndns.org> In-Reply-To: <Pine.LNX.4.62.0712292039410.21327@pop.ict1.everquick.net> References: <5950EE0C-383D-4D6B-9991-A0DEABD2ADE4@u.washington.edu> <7F9D2F63-B5E6-41DE-843A-8D673C2DC88E@u.washington.edu> <Pine.LNX.4.62.0712292039410.21327@pop.ict1.everquick.net>
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--ofZMSlrAVk9bLeVm Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Dec 29, 2007 at 08:50:14PM +0000, Edward B. DREGER wrote: >...have you explored [order-preserving] minimal perfect hash functions? > >perfect_hash =3D ( hash1[x] + hash2[x] ) % entry_count ; This relies on pre-knowledge of all possible entries. It's excellent for (eg) keyword lookups in a compiler (and gcc uses gperf for that reason) but no good where the input can be arbitrary. --=20 Peter Jeremy Please excuse any delays as the result of my ISP's inability to implement an MTA that is either RFC2821-compliant or matches their claimed behaviour. --ofZMSlrAVk9bLeVm Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQFHdr2Z/opHv/APuIcRAixVAJ9FRodz7VA5lSTTb+thHdgUfaj8QgCgktV2 NbDvoyWtAx8XEuzpRIaq+bY= =Xp6K -----END PGP SIGNATURE----- --ofZMSlrAVk9bLeVm--
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