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177 lines
6.4 KiB
177 lines
6.4 KiB
/* |
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xxHash - Fast Hash algorithm |
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Header File |
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Copyright (C) 2012-2014, Yann Collet. |
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BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) |
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Redistribution and use in source and binary forms, with or without |
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modification, are permitted provided that the following conditions are |
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met: |
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* Redistributions of source code must retain the above copyright |
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notice, this list of conditions and the following disclaimer. |
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* Redistributions in binary form must reproduce the above |
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copyright notice, this list of conditions and the following disclaimer |
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in the documentation and/or other materials provided with the |
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distribution. |
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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You can contact the author at : |
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- xxHash source repository : http://code.google.com/p/xxhash/ |
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*/ |
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/* Notice extracted from xxHash homepage : |
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xxHash is an extremely fast Hash algorithm, running at RAM speed limits. |
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It also successfully passes all tests from the SMHasher suite. |
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Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2 Duo @3GHz) |
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Name Speed Q.Score Author |
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xxHash 5.4 GB/s 10 |
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CrapWow 3.2 GB/s 2 Andrew |
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MumurHash 3a 2.7 GB/s 10 Austin Appleby |
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SpookyHash 2.0 GB/s 10 Bob Jenkins |
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SBox 1.4 GB/s 9 Bret Mulvey |
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Lookup3 1.2 GB/s 9 Bob Jenkins |
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SuperFastHash 1.2 GB/s 1 Paul Hsieh |
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CityHash64 1.05 GB/s 10 Pike & Alakuijala |
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FNV 0.55 GB/s 5 Fowler, Noll, Vo |
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CRC32 0.43 GB/s 9 |
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MD5-32 0.33 GB/s 10 Ronald L. Rivest |
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SHA1-32 0.28 GB/s 10 |
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Q.Score is a measure of quality of the hash function. |
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It depends on successfully passing SMHasher test set. |
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10 is a perfect score. |
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*/ |
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#pragma once |
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#if defined (__cplusplus) |
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extern "C" { |
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#endif |
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#include <inttypes.h> |
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struct XXH_state32_t |
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{ |
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uint64_t total_len; |
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uint32_t seed; |
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uint32_t v1; |
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uint32_t v2; |
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uint32_t v3; |
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uint32_t v4; |
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int memsize; |
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char memory[16]; |
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}; |
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//**************************** |
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// Type |
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//**************************** |
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typedef enum { XXH_OK=0, XXH_ERROR } XXH_errorcode; |
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//**************************** |
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// Simple Hash Functions |
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//**************************** |
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uint32_t XXH32 (const void* input, uint32_t len, uint32_t seed); |
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/* |
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XXH32() : |
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Calculate the 32-bits hash of sequence of length "len" stored at memory address "input". |
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The memory between input & input+len must be valid (allocated and read-accessible). |
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"seed" can be used to alter the result predictably. |
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This function successfully passes all SMHasher tests. |
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Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s |
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Note that "len" is type "int", which means it is limited to 2^31-1. |
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If your data is larger, use the advanced functions below. |
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*/ |
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//**************************** |
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// Advanced Hash Functions |
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//**************************** |
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void* XXH32_init (unsigned int seed); |
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XXH_errorcode XXH32_update (void* state, const void* input, int len); |
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unsigned int XXH32_digest (void* state); |
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/* |
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These functions calculate the xxhash of an input provided in several small packets, |
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as opposed to an input provided as a single block. |
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It must be started with : |
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void* XXH32_init() |
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The function returns a pointer which holds the state of calculation. |
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This pointer must be provided as "void* state" parameter for XXH32_update(). |
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XXH32_update() can be called as many times as necessary. |
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The user must provide a valid (allocated) input. |
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The function returns an error code, with 0 meaning OK, and any other value meaning there is an error. |
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Note that "len" is type "int", which means it is limited to 2^31-1. |
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If your data is larger, it is recommended to chunk your data into blocks |
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of size for example 2^30 (1GB) to avoid any "int" overflow issue. |
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Finally, you can end the calculation anytime, by using XXH32_digest(). |
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This function returns the final 32-bits hash. |
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You must provide the same "void* state" parameter created by XXH32_init(). |
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Memory will be freed by XXH32_digest(). |
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*/ |
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int XXH32_sizeofState(void); |
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XXH_errorcode XXH32_resetState(void* state, unsigned int seed); |
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#define XXH32_SIZEOFSTATE 48 |
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typedef struct { long long ll[(XXH32_SIZEOFSTATE+(sizeof(long long)-1))/sizeof(long long)]; } XXH32_stateSpace_t; |
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/* |
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These functions allow user application to make its own allocation for state. |
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XXH32_sizeofState() is used to know how much space must be allocated for the xxHash 32-bits state. |
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Note that the state must be aligned to access 'long long' fields. Memory must be allocated and referenced by a pointer. |
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This pointer must then be provided as 'state' into XXH32_resetState(), which initializes the state. |
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For static allocation purposes (such as allocation on stack, or freestanding systems without malloc()), |
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use the structure XXH32_stateSpace_t, which will ensure that memory space is large enough and correctly aligned to access 'long long' fields. |
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*/ |
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unsigned int XXH32_intermediateDigest (void* state); |
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/* |
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This function does the same as XXH32_digest(), generating a 32-bit hash, |
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but preserve memory context. |
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This way, it becomes possible to generate intermediate hashes, and then continue feeding data with XXH32_update(). |
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To free memory context, use XXH32_digest(), or free(). |
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*/ |
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//**************************** |
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// Deprecated function names |
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//**************************** |
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// The following translations are provided to ease code transition |
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// You are encouraged to no longer this function names |
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#define XXH32_feed XXH32_update |
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#define XXH32_result XXH32_digest |
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#define XXH32_getIntermediateResult XXH32_intermediateDigest |
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#if defined (__cplusplus) |
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} |
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#endif
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