ceph/src/xxHash/xxhash.h

   1 /*
   2    xxHash - Extremely Fast Hash algorithm
   3    Header File
   4    Copyright (C) 2012-2016, Yann Collet.
   5
   6    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
   7
   8    Redistribution and use in source and binary forms, with or without
   9    modification, are permitted provided that the following conditions are
  10    met:
  11
  12        * Redistributions of source code must retain the above copyright
  13    notice, this list of conditions and the following disclaimer.
  14        * Redistributions in binary form must reproduce the above
  15    copyright notice, this list of conditions and the following disclaimer
  16    in the documentation and/or other materials provided with the
  17    distribution.
  18
  19    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  23    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  29    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30
  31    You can contact the author at :
  32    - xxHash source repository : https://github.com/Cyan4973/xxHash
  33 */
  34
  35 /* Notice extracted from xxHash homepage :
  36
  37 xxHash is an extremely fast Hash algorithm, running at RAM speed limits.
  38 It also successfully passes all tests from the SMHasher suite.
  39
  40 Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2 Duo @3GHz)
  41
  42 Name            Speed       Q.Score   Author
  43 xxHash          5.4 GB/s     10
  44 CrapWow         3.2 GB/s      2       Andrew
  45 MumurHash 3a    2.7 GB/s     10       Austin Appleby
  46 SpookyHash      2.0 GB/s     10       Bob Jenkins
  47 SBox            1.4 GB/s      9       Bret Mulvey
  48 Lookup3         1.2 GB/s      9       Bob Jenkins
  49 SuperFastHash   1.2 GB/s      1       Paul Hsieh
  50 CityHash64      1.05 GB/s    10       Pike & Alakuijala
  51 FNV             0.55 GB/s     5       Fowler, Noll, Vo
  52 CRC32           0.43 GB/s     9
  53 MD5-32          0.33 GB/s    10       Ronald L. Rivest
  54 SHA1-32         0.28 GB/s    10
  55
  56 Q.Score is a measure of quality of the hash function.
  57 It depends on successfully passing SMHasher test set.
  58 10 is a perfect score.
  59
  60 A 64-bits version, named XXH64, is available since r35.
  61 It offers much better speed, but for 64-bits applications only.
  62 Name     Speed on 64 bits    Speed on 32 bits
  63 XXH64       13.8 GB/s            1.9 GB/s
  64 XXH32        6.8 GB/s            6.0 GB/s
  65 */
  66
  67 #ifndef XXHASH_H_5627135585666179
  68 #define XXHASH_H_5627135585666179 1
  69
  70 #if defined (__cplusplus)
  71 extern "C" {
  72 #endif
  73
  74
  75 /* ****************************
  76 *  Definitions
  77 ******************************/
  78 #include <stddef.h>   /* size_t */
  79 typedef enum { XXH_OK=0, XXH_ERROR } XXH_errorcode;
  80
  81
  82 /* ****************************
  83 *  API modifier
  84 ******************************/
  85 /*!XXH_PRIVATE_API
  86 *  Transforms all publics symbols within `xxhash.c` into private ones.
  87 *  Methodology :
  88 *  instead of : #include "xxhash.h"
  89 *  do :
  90 *     #define XXH_PRIVATE_API
  91 *     #include "xxhash.c"   // note the .c , instead of .h
  92 *  also : don't compile and link xxhash.c separately
  93 */
  94 #ifdef XXH_PRIVATE_API
  95 #  if defined(__GNUC__)
  96 #    define XXH_PUBLIC_API static __attribute__((unused))
  97 #  elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
  98 #    define XXH_PUBLIC_API static inline
  99 #  elif defined(_MSC_VER)
 100 #    define XXH_PUBLIC_API static __inline
 101 #  else
 102 #    define XXH_PUBLIC_API static   /* this version may generate warnings for unused static functions; disable the relevant warning */
 103 #  endif
 104 #else
 105 #  define XXH_PUBLIC_API   /* do nothing */
 106 #endif
 107
 108 /*!XXH_NAMESPACE, aka Namespace Emulation :
 109
 110 If you want to include _and expose_ xxHash functions from within your own library,
 111 but also want to avoid symbol collisions with another library which also includes xxHash,
 112
 113 you can use XXH_NAMESPACE, to automatically prefix any public symbol from `xxhash.c`
 114 with the value of XXH_NAMESPACE (so avoid to keep it NULL and avoid numeric values).
 115
 116 Note that no change is required within the calling program as long as it also includes `xxhash.h` :
 117 regular symbol name will be automatically translated by this header.
 118 */
 119 #ifdef XXH_NAMESPACE
 120 #  define XXH_CAT(A,B) A##B
 121 #  define XXH_NAME2(A,B) XXH_CAT(A,B)
 122 #  define XXH32 XXH_NAME2(XXH_NAMESPACE, XXH32)
 123 #  define XXH64 XXH_NAME2(XXH_NAMESPACE, XXH64)
 124 #  define XXH_versionNumber XXH_NAME2(XXH_NAMESPACE, XXH_versionNumber)
 125 #  define XXH32_createState XXH_NAME2(XXH_NAMESPACE, XXH32_createState)
 126 #  define XXH64_createState XXH_NAME2(XXH_NAMESPACE, XXH64_createState)
 127 #  define XXH32_freeState XXH_NAME2(XXH_NAMESPACE, XXH32_freeState)
 128 #  define XXH64_freeState XXH_NAME2(XXH_NAMESPACE, XXH64_freeState)
 129 #  define XXH32_reset XXH_NAME2(XXH_NAMESPACE, XXH32_reset)
 130 #  define XXH64_reset XXH_NAME2(XXH_NAMESPACE, XXH64_reset)
 131 #  define XXH32_update XXH_NAME2(XXH_NAMESPACE, XXH32_update)
 132 #  define XXH64_update XXH_NAME2(XXH_NAMESPACE, XXH64_update)
 133 #  define XXH32_digest XXH_NAME2(XXH_NAMESPACE, XXH32_digest)
 134 #  define XXH64_digest XXH_NAME2(XXH_NAMESPACE, XXH64_digest)
 135 #endif
 136
 137
 138 /* *************************************
 139 *  Version
 140 ***************************************/
 141 #define XXH_VERSION_MAJOR    0
 142 #define XXH_VERSION_MINOR    5
 143 #define XXH_VERSION_RELEASE  1
 144 #define XXH_VERSION_NUMBER  (XXH_VERSION_MAJOR *100*100 + XXH_VERSION_MINOR *100 + XXH_VERSION_RELEASE)
 145 XXH_PUBLIC_API unsigned XXH_versionNumber (void);
 146
 147
 148 /* ****************************
 149 *  Simple Hash Functions
 150 ******************************/
 151 typedef unsigned int       XXH32_hash_t;
 152 typedef unsigned long long XXH64_hash_t;
 153
 154 XXH_PUBLIC_API XXH32_hash_t XXH32 (const void* input, size_t length, unsigned int seed);
 155 XXH_PUBLIC_API XXH64_hash_t XXH64 (const void* input, size_t length, unsigned long long seed);
 156
 157 /*!
 158 XXH32() :
 159     Calculate the 32-bits hash of sequence "length" bytes stored at memory address "input".
 160     The memory between input & input+length must be valid (allocated and read-accessible).
 161     "seed" can be used to alter the result predictably.
 162     Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s
 163 XXH64() :
 164     Calculate the 64-bits hash of sequence of length "len" stored at memory address "input".
 165     "seed" can be used to alter the result predictably.
 166     This function runs faster on 64-bits systems, but slower on 32-bits systems (see benchmark).
 167 */
 168
 169
 170 /* ****************************
 171 *  Streaming Hash Functions
 172 ******************************/
 173 typedef struct XXH32_state_s XXH32_state_t;   /* incomplete type */
 174 typedef struct XXH64_state_s XXH64_state_t;   /* incomplete type */
 175
 176
 177 /*! Static allocation
 178     For static linking only, do not use in the context of DLL !
 179         XXHnn_CREATESTATE_STATIC(name);
 180             is static-allocation equivalent of :
 181         XXHnn_state_t* name = XXHnn_createState();
 182 */
 183 typedef struct { long long ll[ 6]; } XXH32_stateBody_t;
 184 typedef struct { long long ll[11]; } XXH64_stateBody_t;
 185
 186 #define XXH32_CREATESTATE_STATIC(name) XXH32_stateBody_t name##xxhbody; void* name##xxhvoid = &(name##xxhbody); XXH32_state_t* name = (XXH32_state_t*)(name##xxhvoid)   /* no final ; */
 187 #define XXH64_CREATESTATE_STATIC(name) XXH64_stateBody_t name##xxhbody; void* name##xxhvoid = &(name##xxhbody); XXH64_state_t* name = (XXH64_state_t*)(name##xxhvoid)   /* no final ; */
 188
 189
 190 /*!Dynamic allocation
 191    To be preferred in the context of DLL */
 192
 193 XXH_PUBLIC_API XXH32_state_t* XXH32_createState(void);
 194 XXH_PUBLIC_API XXH_errorcode  XXH32_freeState(XXH32_state_t* statePtr);
 195
 196 XXH_PUBLIC_API XXH64_state_t* XXH64_createState(void);
 197 XXH_PUBLIC_API XXH_errorcode  XXH64_freeState(XXH64_state_t* statePtr);
 198
 199
 200 /* hash streaming */
 201
 202 XXH_PUBLIC_API XXH_errorcode XXH32_reset  (XXH32_state_t* statePtr, unsigned int seed);
 203 XXH_PUBLIC_API XXH_errorcode XXH32_update (XXH32_state_t* statePtr, const void* input, size_t length);
 204 XXH_PUBLIC_API XXH32_hash_t  XXH32_digest (const XXH32_state_t* statePtr);
 205
 206 XXH_PUBLIC_API XXH_errorcode XXH64_reset  (XXH64_state_t* statePtr, unsigned long long seed);
 207 XXH_PUBLIC_API XXH_errorcode XXH64_update (XXH64_state_t* statePtr, const void* input, size_t length);
 208 XXH_PUBLIC_API XXH64_hash_t  XXH64_digest (const XXH64_state_t* statePtr);
 209
 210 /*!
 211 These functions generate the xxHash of an input provided in multiple segments,
 212 as opposed to provided as a single block.
 213
 214 XXH state must first be allocated, using either static or dynamic method provided above.
 215
 216 Start a new hash by initializing state with a seed, using XXHnn_reset().
 217
 218 Then, feed the hash state by calling XXHnn_update() as many times as necessary.
 219 Obviously, input must be valid, hence allocated and read accessible.
 220 The function returns an error code, with 0 meaning OK, and any other value meaning there is an error.
 221
 222 Finally, a hash value can be produced anytime, by using XXHnn_digest().
 223 This function returns the nn-bits hash as an int or long long.
 224
 225 It's still possible to continue inserting input into the hash state after a digest,
 226 and later on generate some new hashes, by calling again XXHnn_digest().
 227
 228 When done, free XXH state space if it was allocated dynamically.
 229 */
 230
 231
 232 /* **************************
 233 *  Canonical representation
 234 ****************************/
 235 typedef struct { unsigned char digest[4]; } XXH32_canonical_t;
 236 typedef struct { unsigned char digest[8]; } XXH64_canonical_t;
 237
 238 XXH_PUBLIC_API void XXH32_canonicalFromHash(XXH32_canonical_t* dst, XXH32_hash_t hash);
 239 XXH_PUBLIC_API void XXH64_canonicalFromHash(XXH64_canonical_t* dst, XXH64_hash_t hash);
 240
 241 XXH_PUBLIC_API XXH32_hash_t XXH32_hashFromCanonical(const XXH32_canonical_t* src);
 242 XXH_PUBLIC_API XXH64_hash_t XXH64_hashFromCanonical(const XXH64_canonical_t* src);
 243
 244 /*! Default result type for XXH functions are primitive unsigned 32 and 64 bits.
 245 *   The canonical representation uses human-readable write convention, aka big-endian (large digits first).
 246 *   These functions allow transformation of hash result into and from its canonical format.
 247 *   This way, hash values can be written into a file / memory, and remain comparable on different systems and programs.
 248 */
 249
 250
 251 #if defined (__cplusplus)
 252 }
 253 #endif
 254
 255 #endif /* XXHASH_H_5627135585666179 */