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Groups > comp.lang.c++ > #81979

Re: faster "CRC"- / "FNV"-hashing

From Bonita Montero <Bonita.Montero@gmail.com>
Newsgroups comp.lang.c++
Subject Re: faster "CRC"- / "FNV"-hashing
Date 2021-10-11 08:33 +0200
Organization A noiseless patient Spider
Message-ID <sk0lrs$fvr$1@dont-email.me> (permalink)
References <sjv5nb$7sp$1@dont-email.me> <3TP8J.82248$tG6.21234@fx39.iad> <sk0lga$94q$1@dont-email.me> <WTQ8J.225542$T_8.141095@fx48.iad>

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Am 11.10.2021 um 08:32 schrieb Branimir Maksimovic:

>> CRC64_ECMA182::crc64_table::crc64_table()
>> {
>> 	uint64_t const CRC64_ECMA182_POLY = 0x42F0E1EBA9EA3693u;
>> 	for( uint64_t i = 0; i != 256; ++i )
>> 	{
>> 		uint64_t crc = 0,
>> 		         c   = i << 56;
>> 		for( unsigned j = 0; j != 8; ++j )
>> 			crc = (int64_t)(crc ^ c) < 0 ? (crc << 1) ^ CRC64_ECMA182_POLY : crc
>> << 1,
>> 			c <<= 1;
>> 		t[(size_t)i] = crc;
>> 	}
>> }
>>
>> CRC64_ECMA182::crc64_table CRC64_ECMA182::table;
>>
>> Why does it run faster ?
> Dunno, haven't have need to calculate crc64 yet :P
> Better to generate table, don't waste time on generation :P

Eeeh, I'm using also a table as you can see from above.

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Thread

faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-10 18:51 +0200
  Re: faster "CRC"- / "FNV"-hashing "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-10-10 12:36 -0700
    Re: faster "CRC"- / "FNV"-hashing scott@slp53.sl.home (Scott Lurndal) - 2021-10-10 22:51 +0000
      Re: faster "CRC"- / "FNV"-hashing "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-10-12 13:47 -0700
    Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 08:09 +0200
  Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 05:23 +0000
    Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 08:15 +0200
      Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 06:29 +0000
        Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 08:34 +0200
    Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 08:27 +0200
      Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 06:32 +0000
        Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 08:33 +0200
          Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 07:46 +0000
            Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 10:53 +0200
              Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 09:11 +0000
                Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 11:18 +0200
                Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 10:42 +0000
                Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 13:03 +0200
                Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 11:12 +0000
                Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 13:44 +0200
                Re: faster "CRC"- / "FNV"-hashing Bo Persson <bo@bo-persson.se> - 2021-10-11 13:58 +0200
                Re: faster "CRC"- / "FNV"-hashing David Brown <david.brown@hesbynett.no> - 2021-10-11 14:23 +0200
                Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 12:56 +0000
                Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 15:55 +0200
                Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 16:55 +0000
                Re: faster "CRC"- / "FNV"-hashing RadicalRabbit@theburrow.co.uk - 2021-10-12 09:06 +0000
                Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-12 11:01 +0000
                Re: faster "CRC"- / "FNV"-hashing RadicalRabbit@theburrow.co.uk - 2021-10-12 14:49 +0000
                Re: faster "CRC"- / "FNV"-hashing David Brown <david.brown@hesbynett.no> - 2021-10-11 17:19 +0200
                Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 16:57 +0000
  Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 05:41 +0000

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