Re: Good hash for pointers

From	bart <bc@freeuk.com>
Newsgroups	comp.lang.c
Subject	Re: Good hash for pointers
Date	2024-05-24 11:14 +0100
Organization	A noiseless patient Spider
Message-ID	<v2ppac$29ca1$1@dont-email.me> (permalink)
References	(1 earlier) <86v834i1o9.fsf@linuxsc.com> <v2okbv$1vp4n$2@dont-email.me> <86r0dshysc.fsf@linuxsc.com> <v2omvt$2049k$1@dont-email.me> <86ed9shtsj.fsf@linuxsc.com>

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On 24/05/2024 02:39, Tim Rentsch wrote:
> Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:
> 
>> On 24/05/2024 00:52, Tim Rentsch wrote:
>>
>>> Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:
>>>
>>>> On 23/05/2024 23:49, Tim Rentsch wrote:
>>>>
>>>>> Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:
>>>>>
>>>>>> What is a good hash function for pointers to use in portable
>>>>>> ANSI C?
>>>>>
>>>>> I have a preliminary question.  Do you really mean ANSI C, or
>>>>> is C99 acceptable?
>>>>
>>>> C89 is better.
>>>> But the pass has been sold.
>>>
>>> I'm not asking which you think is better.  I'm asking about
>>> what your requirements are.
>>
>> C 89.
>> I don't want to pull in C99 types and so on just for a hash function.
> 
> In that case I think you are stuck with using a half-baked
> solution.  The standard integer types available in C89 just
> aren't a good fit in a 64-bit world.

I assume the C89 implementation is one that can target current 64 bit 
machines.

Then char, short, int, long long will almost certainly have widths of 8, 
16, 32 and 64 bits respectively.

(I don't know if 'long long' was part of C89, but it sounds like Malcolm 
just doesn't want to be bothered with stdint.h, and any compiler used is 
like to support it.

I can't stand it either. Just today I wrote these two lines:

   typedef unsigned long long u64;
   typedef unsigned char byte;

to avoid stdint.h and its ugly set of types.)

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Thread

Good hash for pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-05-23 12:11 +0100
  Re: Good hash for pointers Richard Harnden <richard.nospam@gmail.invalid> - 2024-05-23 15:37 +0100
    Re: Good hash for pointers Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-05-23 15:51 -0700
      Re: Good hash for pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-05-24 00:42 +0100
  Re: Good hash for pointers Kaz Kylheku <643-408-1753@kylheku.com> - 2024-05-23 20:34 +0000
  Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-23 15:49 -0700
    Re: Good hash for pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-05-24 00:43 +0100
      Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-23 16:52 -0700
        Re: Good hash for pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-05-24 01:28 +0100
          Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-23 18:39 -0700
            Re: Good hash for pointers bart <bc@freeuk.com> - 2024-05-24 11:14 +0100
              Re: Good hash for pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-05-24 12:05 +0100
                Re: Good hash for pointers "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-24 10:49 -0700
                Re: Good hash for pointers "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-24 10:51 -0700
              Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-24 06:18 -0700
                Re: Good hash for pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-05-24 15:07 +0100
                Re: Good hash for pointers scott@slp53.sl.home (Scott Lurndal) - 2024-05-24 14:51 +0000
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-25 02:49 -0700
              Re: Good hash for pointers David Brown <david.brown@hesbynett.no> - 2024-05-24 17:00 +0200
                Re: Good hash for pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-05-24 17:10 +0100
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-05-24 19:27 +0300
          Re: Good hash for pointers David Brown <david.brown@hesbynett.no> - 2024-05-24 09:41 +0200
  Re: Good hash for pointers "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-23 17:32 -0700
    Re: Good hash for pointers "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-23 18:59 -0700
      Re: Good hash for pointers jak <nospam@please.ty> - 2024-05-24 04:09 +0200
  Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-24 20:28 +0200
    Re: Good hash for pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-05-24 19:57 +0100
      Re: Good hash for pointers bart <bc@freeuk.com> - 2024-05-25 00:54 +0100
        Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-25 02:12 -0700
          Re: Good hash for pointers bart <bc@freeuk.com> - 2024-05-25 12:28 +0100
            Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-25 11:12 -0700
              Re: Good hash for pointers bart <bc@freeuk.com> - 2024-05-25 20:31 +0100
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-25 22:54 -0700
          Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-25 17:00 +0200
            Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-25 10:40 -0700
              Re: Good hash for pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-05-25 18:56 +0100
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-25 11:23 -0700
                Re: Good hash for pointers Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-05-25 23:13 +0200
                Re: Good hash for pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-05-25 23:07 +0100
                Re: Good hash for pointers bart <bc@freeuk.com> - 2024-05-25 23:42 +0100
                Re: Good hash for pointers Richard Harnden <richard.nospam@gmail.invalid> - 2024-05-26 19:58 +0100
                Re: Good hash for pointers Kaz Kylheku <643-408-1753@kylheku.com> - 2024-05-26 22:42 +0000
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-26 18:05 +0200
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-26 18:07 +0200
              Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-26 18:04 +0200
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-26 09:24 -0700
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-26 18:36 +0200
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-26 10:20 -0700
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-26 19:39 +0200
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-26 19:54 +0200
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-27 08:07 +0200
                Re: Good hash for pointers Ben Bacarisse <ben@bsb.me.uk> - 2024-05-28 11:07 +0100
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-30 10:10 +0200
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-30 11:27 +0200
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-30 19:26 -0700
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-30 19:27 -0700
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-02 10:45 +0300
                Re: Good hash for pointers "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-02 12:42 -0700
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-02 16:02 -0700
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-03 10:50 +0300
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-03 16:34 +0200
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-03 17:46 +0300
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-03 17:54 +0200
                Re: Good hash for pointers bart <bc@freeuk.com> - 2024-06-03 17:24 +0100
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-03 20:16 +0300
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-03 19:50 +0300
  Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-26 20:06 +0200
    Re: Good hash for pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-05-26 20:10 +0100
  Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-26 20:24 +0200

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