Re: libstdc++/3552: missing hash function for std::string

[Phil Edwards <phil@jaj.com>]

The following reply was made to PR libstdc++/3552; it has been noted by GNATS.

From: Phil Edwards <phil@jaj.com>
To: Goswin Brederlow <goswin.brederlow@student.uni-tuebingen.de>
Cc: Vadim Ogranovich <vograno@arbitrade.com>,
   "'gcc-gnats@gcc.gnu.org'" <gcc-gnats@gcc.gnu.org>,
   "'Laurent.Bonnaud@inpg.fr'" <Laurent.Bonnaud@inpg.fr>,
   "'87063-quiet@bugs.debian.org'" <87063-quiet@bugs.debian.org>,
   "'gcc-bugs@gcc.gnu.org'" <gcc-bugs@gcc.gnu.org>
Subject: Re: libstdc++/3552: missing hash function for std::string
Date: Wed, 8 May 2002 14:38:48 -0400

 On Wed, May 08, 2002 at 07:01:45PM +0200, Goswin Brederlow wrote:
 > > Yes.  How can we possibly guess what a good hash function would be for
 > > arbitrary strings?  Efficiency of hashing is extremely dependant on the
 > > data being hashed.  You need to write one that's appropriate for your data;
 > > this will involve multiple experiments.
 > > 
 > > There is std::collate::hash() for char*'s, but this is essentially a
 > > generic guess, and should only be used when you haven't yet had the time
 > > to come up with a more appropriate function.
 > 
 > Having one for char* but not for string is a bit of a contradiction.
 
 I'd like to remove the one for char*, actually...
 
 The implementation of hashing currently being proposed for C++0x apparently
 uses a completely different interface.  I'd rather just improve the
 (eventual) standard version, rather than kicking along the extensions that
 we inherited.
 
 
 Phil
 
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