X-Git-Url: https://git.m6w6.name/?a=blobdiff_plain;f=src%2Flibhashkit%2Fmurmur.cc;h=5ad796b19bb647437cb9886d8be0c866b525980d;hb=e1ba5b9e4eb179295274026ad8fd40a68eb6c67f;hp=c1451639c57a67a069683892e4f5972f24f1262c;hpb=a7998e86ec86a8e76323597dd024432643ab2067;p=awesomized%2Flibmemcached diff --git a/src/libhashkit/murmur.cc b/src/libhashkit/murmur.cc index c1451639..5ad796b1 100644 --- a/src/libhashkit/murmur.cc +++ b/src/libhashkit/murmur.cc @@ -1,95 +1,53 @@ -/* vim:expandtab:shiftwidth=2:tabstop=2:smarttab: - * - * HashKit library - * - * Copyright (C) 2011-2012 Data Differential, http://datadifferential.com/ - * Copyright (C) 2006-2009 Brian Aker All rights reserved. - * - * 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. - * - * * The names of its contributors may not be used to endorse or - * promote products derived from this software without specific prior - * written permission. - * - * 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. - * - */ - /* - "Murmur" hash provided by Austin, tanjent@gmail.com - http://murmurhash.googlepages.com/ - - Note - This code makes a few assumptions about how your machine behaves - - - 1. We can read a 4-byte value from any address without crashing - 2. sizeof(int) == 4 - - And it has a few limitations - - 1. It will not work incrementally. - 2. It will not produce the same results on little-endian and big-endian - machines. - - Updated to murmur2 hash - BP + +--------------------------------------------------------------------+ + | libmemcached - C/C++ Client Library for memcached | + +--------------------------------------------------------------------+ + | Redistribution and use in source and binary forms, with or without | + | modification, are permitted under the terms of the BSD license. | + | You should have received a copy of the license in a bundled file | + | named LICENSE; in case you did not receive a copy you can review | + | the terms online at: https://opensource.org/licenses/BSD-3-Clause | + +--------------------------------------------------------------------+ + | Copyright (c) 2006-2014 Brian Aker https://datadifferential.com/ | + | Copyright (c) 2020 Michael Wallner | + +--------------------------------------------------------------------+ */ #include "libhashkit/common.h" #ifdef HAVE_MURMUR_HASH -#ifdef BYTESWAP_HEADER -# include BYTESWAP_HEADER -#endif +# ifdef BYTESWAP_HEADER +# include BYTESWAP_HEADER +# endif -#include +# include -uint32_t hashkit_murmur(const char *key, size_t length, void *context) -{ +uint32_t hashkit_murmur(const char *key, size_t length, void *context) { /* 'm' and 'r' are mixing constants generated offline. They're not really 'magic', they just happen to work well. */ - const unsigned int m= 0x5bd1e995; - const uint32_t seed= (0xdeadbeef * (uint32_t)length); - const int r= 24; - + const unsigned int m = 0x5bd1e995; + const uint32_t seed = (0xdeadbeef * (uint32_t) length); + const int r = 24; // Initialize the hash to a 'random' value - uint32_t h= seed ^ (uint32_t)length; + uint32_t h = seed ^ (uint32_t) length; // Mix 4 bytes at a time into the hash - const unsigned char * data= (const unsigned char *)key; - (void)context; + const unsigned char *data = (const unsigned char *) key; + (void) context; - while(length >= 4) - { + while (length >= 4) { uint32_t k; memcpy(&k, data, sizeof(k)); -#if WORDS_BIGENDIAN +# if WORDS_BIGENDIAN k = BYTESWAP_32(k); -#endif +# endif k *= m; k ^= k >> r; @@ -106,9 +64,9 @@ uint32_t hashkit_murmur(const char *key, size_t length, void *context) if (length) { uint32_t k = 0; memcpy(&k, data, length); -#if WORDS_BIGENDIAN +# if WORDS_BIGENDIAN k = BYTESWAP_32(k); -#endif +# endif h ^= k; h *= m; } @@ -126,8 +84,7 @@ uint32_t hashkit_murmur(const char *key, size_t length, void *context) } #else -uint32_t hashkit_murmur(const char *, size_t , void *) -{ +uint32_t hashkit_murmur(const char *, size_t, void *) { return 0; } #endif