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| -rw-r--r-- | src/rocksdb/util/xxhash.h | 240 |
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diff --git a/src/rocksdb/util/xxhash.h b/src/rocksdb/util/xxhash.h new file mode 100644 index 00000000..88352ac7 --- /dev/null +++ b/src/rocksdb/util/xxhash.h @@ -0,0 +1,240 @@ +/* + xxHash - 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 + +#include <stdlib.h> + +#if !defined(__VMS) && \ + (defined(__cplusplus) || \ + (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)) +#include <stdint.h> +#endif + +#if defined (__cplusplus) +namespace rocksdb { +#endif + + +//**************************** +// Type +//**************************** +/* size_t */ +typedef enum { XXH_OK=0, XXH_ERROR } XXH_errorcode; + + + +//**************************** +// Simple Hash Functions +//**************************** + +unsigned int XXH32 (const void* input, int len, unsigned int seed); + +/* +XXH32() : + Calculate the 32-bits hash of sequence of length "len" stored at memory address "input". + The memory between input & input+len 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 + Note that "len" is type "int", which means it is limited to 2^31-1. + If your data is larger, use the advanced functions below. +*/ + + + +//**************************** +// Advanced Hash Functions +//**************************** + +void* XXH32_init (unsigned int seed); +XXH_errorcode XXH32_update (void* state, const void* input, int len); +unsigned int XXH32_digest (void* state); + +/* +These functions calculate the xxhash of an input provided in several small packets, +as opposed to an input provided as a single block. + +It must be started with : +void* XXH32_init() +The function returns a pointer which holds the state of calculation. + +This pointer must be provided as "void* state" parameter for XXH32_update(). +XXH32_update() can be called as many times as necessary. +The user must provide a valid (allocated) input. +The function returns an error code, with 0 meaning OK, and any other value meaning there is an error. +Note that "len" is type "int", which means it is limited to 2^31-1. +If your data is larger, it is recommended to chunk your data into blocks +of size for example 2^30 (1GB) to avoid any "int" overflow issue. + +Finally, you can end the calculation anytime, by using XXH32_digest(). +This function returns the final 32-bits hash. +You must provide the same "void* state" parameter created by XXH32_init(). +Memory will be freed by XXH32_digest(). +*/ + + +int XXH32_sizeofState(); +XXH_errorcode XXH32_resetState(void* state, unsigned int seed); + +#define XXH32_SIZEOFSTATE 48 +typedef struct { long long ll[(XXH32_SIZEOFSTATE+(sizeof(long long)-1))/sizeof(long long)]; } XXH32_stateSpace_t; +/* +These functions allow user application to make its own allocation for state. + +XXH32_sizeofState() is used to know how much space must be allocated for the xxHash 32-bits state. +Note that the state must be aligned to access 'long long' fields. Memory must be allocated and referenced by a pointer. +This pointer must then be provided as 'state' into XXH32_resetState(), which initializes the state. + +For static allocation purposes (such as allocation on stack, or freestanding systems without malloc()), +use the structure XXH32_stateSpace_t, which will ensure that memory space is large enough and correctly aligned to access 'long long' fields. +*/ + + +unsigned int XXH32_intermediateDigest (void* state); +/* +This function does the same as XXH32_digest(), generating a 32-bit hash, +but preserve memory context. +This way, it becomes possible to generate intermediate hashes, and then continue feeding data with XXH32_update(). +To free memory context, use XXH32_digest(), or free(). +*/ + + + +//**************************** +// Deprecated function names +//**************************** +// The following translations are provided to ease code transition +// You are encouraged to no longer this function names +#define XXH32_feed XXH32_update +#define XXH32_result XXH32_digest +#define XXH32_getIntermediateResult XXH32_intermediateDigest + +/*-********************************************************************** + * 64-bit hash + ************************************************************************/ +typedef unsigned long long XXH64_hash_t; + +/*! XXH64() : + Calculate the 64-bit hash of sequence of length "len" stored at memory + address "input". "seed" can be used to alter the result predictably. This + function runs faster on 64-bit systems, but slower on 32-bit systems (see + benchmark). +*/ +XXH64_hash_t XXH64(const void* input, size_t length, unsigned long long seed); + +/*====== Streaming ======*/ +typedef struct XXH64_state_s XXH64_state_t; /* incomplete type */ +XXH64_state_t* XXH64_createState(void); +XXH_errorcode XXH64_freeState(XXH64_state_t* statePtr); +void XXH64_copyState(XXH64_state_t* dst_state, const XXH64_state_t* src_state); + +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); +XXH64_hash_t XXH64_digest(const XXH64_state_t* statePtr); + +/*====== Canonical representation ======*/ +typedef struct { + unsigned char digest[8]; +} XXH64_canonical_t; +void XXH64_canonicalFromHash(XXH64_canonical_t* dst, XXH64_hash_t hash); +XXH64_hash_t XXH64_hashFromCanonical(const XXH64_canonical_t* src); + +/* These definitions are only present to allow + * static allocation of XXH state, on stack or in a struct for example. + * Never **ever** use members directly. */ + +#if !defined(__VMS) && \ + (defined(__cplusplus) || \ + (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)) + +struct XXH64_state_s { + uint64_t total_len; + uint64_t v1; + uint64_t v2; + uint64_t v3; + uint64_t v4; + uint64_t mem64[4]; + uint32_t memsize; + uint32_t reserved[2]; /* never read nor write, might be removed in a future + version */ +}; /* typedef'd to XXH64_state_t */ + +#else + +#ifndef XXH_NO_LONG_LONG /* remove 64-bit support */ +struct XXH64_state_s { + unsigned long long total_len; + unsigned long long v1; + unsigned long long v2; + unsigned long long v3; + unsigned long long v4; + unsigned long long mem64[4]; + unsigned memsize; + unsigned reserved[2]; /* never read nor write, might be removed in a future + version */ +}; /* typedef'd to XXH64_state_t */ +#endif + +#endif + +#if defined (__cplusplus) +} // namespace rocksdb +#endif |