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Diffstat (limited to 'lib/xxhash.h')
-rw-r--r-- | lib/xxhash.h | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/lib/xxhash.h b/lib/xxhash.h new file mode 100644 index 0000000..55b4501 --- /dev/null +++ b/lib/xxhash.h @@ -0,0 +1,156 @@ +/* + xxHash - Extremely Fast Hash algorithm + Header File + Copyright (C) 2012-2014, Yann Collet. + BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are + met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following disclaimer + in the documentation and/or other materials provided with the + distribution. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + + You can contact the author at : + - xxHash source repository : http://code.google.com/p/xxhash/ +*/ + +/* Notice extracted from xxHash homepage : + +xxHash is an extremely fast Hash algorithm, running at RAM speed limits. +It also successfully passes all tests from the SMHasher suite. + +Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2 Duo @3GHz) + +Name Speed Q.Score Author +xxHash 5.4 GB/s 10 +CrapWow 3.2 GB/s 2 Andrew +MumurHash 3a 2.7 GB/s 10 Austin Appleby +SpookyHash 2.0 GB/s 10 Bob Jenkins +SBox 1.4 GB/s 9 Bret Mulvey +Lookup3 1.2 GB/s 9 Bob Jenkins +SuperFastHash 1.2 GB/s 1 Paul Hsieh +CityHash64 1.05 GB/s 10 Pike & Alakuijala +FNV 0.55 GB/s 5 Fowler, Noll, Vo +CRC32 0.43 GB/s 9 +MD5-32 0.33 GB/s 10 Ronald L. Rivest +SHA1-32 0.28 GB/s 10 + +Q.Score is a measure of quality of the hash function. +It depends on successfully passing SMHasher test set. +10 is a perfect score. +*/ + +#pragma once + +#if defined (__cplusplus) +extern "C" { +#endif + + +/***************************** + Includes +*****************************/ +#include <stddef.h> /* size_t */ + + +/***************************** + Type +*****************************/ +typedef enum { XXH_OK=0, XXH_ERROR } XXH_errorcode; + + + +/***************************** + Simple Hash Functions +*****************************/ + +unsigned int XXH32 (const void* input, size_t length, unsigned seed); +unsigned long long XXH64 (const void* input, size_t length, unsigned long long seed); + +/* +XXH32() : + Calculate the 32-bits hash of sequence "length" bytes stored at memory address "input". + The memory between input & input+length must be valid (allocated and read-accessible). + "seed" can be used to alter the result predictably. + This function successfully passes all SMHasher tests. + Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s +XXH64() : + Calculate the 64-bits hash of sequence of length "len" stored at memory address "input". +*/ + + + +/***************************** + Advanced Hash Functions +*****************************/ +typedef struct { long long ll[ 6]; } XXH32_state_t; +typedef struct { long long ll[11]; } XXH64_state_t; + +/* +These structures allow static allocation of XXH states. +States must then be initialized using XXHnn_reset() before first use. + +If you prefer dynamic allocation, please refer to functions below. +*/ + +XXH32_state_t* XXH32_createState(void); +XXH_errorcode XXH32_freeState(XXH32_state_t* statePtr); + +XXH64_state_t* XXH64_createState(void); +XXH_errorcode XXH64_freeState(XXH64_state_t* statePtr); + +/* +These functions create and release memory for XXH state. +States must then be initialized using XXHnn_reset() before first use. +*/ + + +XXH_errorcode XXH32_reset (XXH32_state_t* statePtr, unsigned seed); +XXH_errorcode XXH32_update (XXH32_state_t* statePtr, const void* input, size_t length); +unsigned int XXH32_digest (const XXH32_state_t* statePtr); + +XXH_errorcode XXH64_reset (XXH64_state_t* statePtr, unsigned long long seed); +XXH_errorcode XXH64_update (XXH64_state_t* statePtr, const void* input, size_t length); +unsigned long long XXH64_digest (const XXH64_state_t* statePtr); + +/* +These functions calculate the xxHash of an input provided in multiple smaller packets, +as opposed to an input provided as a single block. + +XXH state space must first be allocated, using either static or dynamic method provided above. + +Start a new hash by initializing state with a seed, using XXHnn_reset(). + +Then, feed the hash state by calling XXHnn_update() as many times as necessary. +Obviously, input must be valid, meaning allocated and read accessible. +The function returns an error code, with 0 meaning OK, and any other value meaning there is an error. + +Finally, you can produce a hash anytime, by using XXHnn_digest(). +This function returns the final nn-bits hash. +You can nonetheless continue feeding the hash state with more input, +and therefore get some new hashes, by calling again XXHnn_digest(). + +When you are done, don't forget to free XXH state space, using typically XXHnn_freeState(). +*/ + + +#if defined (__cplusplus) +} +#endif |