Ichthyostega
4a53ef4cd0
makes the test logs way more readable Believe me: no one will ever notice a "TODO" entry in the logs, when it showed up for more than some months. Thus I've created some new tickets, mostly tagged as "QA" and placed the ticket number at the corresponding locations in the source
171 lines
5.1 KiB
C
171 lines
5.1 KiB
C
/*
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HASH-FNV.h - FNV hash functions
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Copyright (C)
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2010, 2011, Christian Thaeter <ct@pipapo.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, contact Christian Thaeter <ct@pipapo.org>.
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The actual fnv functions are taken from Landon Curt Noll's original code, no copyright applies:
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***
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*
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* Please do not copyright this code. This code is in the public domain.
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*
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* LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
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* EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
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* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
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* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*
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* By:
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* chongo <Landon Curt Noll> /\oo/\
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* http://www.isthe.com/chongo/
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*
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* Share and Enjoy! :-)
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*/
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/**
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* @file
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* Fowler / Noll / Vo (FNV) Hashes
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*/
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#ifndef HASH_FNV_H
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#define HASH_FNV_H
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#include <stdlib.h> /* for size_t */
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#include <inttypes.h>
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#define HASH_FNV64_BASE ((uint64_t)14695981039346656037ULL)
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#define HASH_FNV32_BASE ((uint32_t)2166136261UL)
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#define HASH_FNV64_PRIME ((uint64_t)1099511628211ULL)
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#define HASH_FNV32_PRIME ((uint32_t)16777619UL)
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/**
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* FNV-1a 64 bit hash over a buffer.
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* @param buf start of the buffer
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* @param len size of the buffer
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* @param hval previous hash value when incremental hashing or HASH_FNV64_BASE when starting a new hash
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* @return new hash value
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*/
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uint64_t
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hash_fnv64a_buf (const void *buf, size_t len, uint64_t hval);
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/**
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* FNV-1a 64 bit hash over a zero terminated string.
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* @param buf start of the buffer
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* @param len maximum size to be processed
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* @param hval previous hash value when incremental hashing or HASH_FNV64_BASE when starting a new hash
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* @return new hash value
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*/
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uint64_t
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hash_fnv64a_strn (const char* str, size_t len, uint64_t hval);
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/**
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* FNV-1a 32 bit hash over a buffer.
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* @param buf start of the buffer
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* @param len size of the buffer
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* @param hval previous hash value when incremental hashing or HASH_FNV32_BASE when starting a new hash
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* @return new hash value
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*/
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uint32_t
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hash_fnv32a_buf (const void *buf, size_t len, uint32_t hval);
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/**
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* FNV-1a 32 bit hash over a zero terminated string.
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* @param buf start of the buffer
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* @param len maximum size to be processed
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* @param hval previous hash value when incremental hashing or HASH_FNV32_BASE when starting a new hash
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* @return new hash value
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*/
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uint32_t
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hash_fnv32a_strn (const char* str, size_t len, uint32_t hval);
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/**
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* reduce a hash value to n bits.
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* Uses the xor folding method to stash a hash value together, this preserves unbiased hash distribution
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* @param hash result from one of the 64 bit hash functions above
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* @param bits number of significat bits for the result
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* @result hashvalue with no more than 'bits' significant bits
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*/
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uint64_t
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hash_fnv64_xorfold (uint64_t hash, int bits);
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/**
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* reduce a hash value to n bits.
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* Uses the xor folding method to stash a hash value together, this preserves unbiased hash distribution
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* @param hash result from one of the 32 bit hash functions above
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* @param bits number of significat bits for the result
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* @result hashvalue with no more than 'bits' significant bits
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*/
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uint32_t
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hash_fnv32_xorfold (uint32_t hash, int bits);
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/**
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* reduce hash to be within 0 to limit-1.
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* Uses the retry method to limit a hash value, this preserves unbiased hash distribution.
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* @param hash result from one of the 64 bit hash functions above
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* @param limit upper limit plus one for the result
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* @result hashvalue in the range from 0 to limit-1
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*/
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uint64_t
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hash_fnv64_retry (uint64_t hash, uint64_t limit);
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/**
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* reduce hash to be within 0 to limit-1.
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* Uses the retry method to limit a hash value, this preserves unbiased hash distribution.
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* @param hash result from one of the 32 bit hash functions above
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* @param limit upper limit plus one for the result
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* @result hashvalue in the range from 0 to limit-1
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*/
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uint32_t
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hash_fnv32_retry (uint64_t hash, uint32_t limit);
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/*
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PLANNED? 128 bit and 256bit hashes
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128 bit FNV_prime = 288 + 28 + 0x3b = 309485009821345068724781371
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256 bit FNV_prime = 2168 + 28 + 0x63 = 374144419156711147060143317175368453031918731002211
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128 bit offset_basis = 144066263297769815596495629667062367629
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256 bit offset_basis =
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100029257958052580907070968620625704837092796014241193945225284501741471925557
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*/
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#endif
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/*
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// Local Variables:
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// mode: C
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// c-file-style: "gnu"
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// indent-tabs-mode: nil
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// End:
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*/
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