comparison: ucx/cx/hash_key.h
ucx/cx/hash_key.h
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| 1 /* | |
| 2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. | |
| 3 * | |
| 4 * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved. | |
| 5 * | |
| 6 * Redistribution and use in source and binary forms, with or without | |
| 7 * modification, are permitted provided that the following conditions are met: | |
| 8 * | |
| 9 * 1. Redistributions of source code must retain the above copyright | |
| 10 * notice, this list of conditions and the following disclaimer. | |
| 11 * | |
| 12 * 2. Redistributions in binary form must reproduce the above copyright | |
| 13 * notice, this list of conditions and the following disclaimer in the | |
| 14 * documentation and/or other materials provided with the distribution. | |
| 15 * | |
| 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE | |
| 20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 26 * POSSIBILITY OF SUCH DAMAGE. | |
| 27 */ | |
| 28 /** | |
| 29 * \file hash_key.h | |
| 30 * \brief Interface for map implementations. | |
| 31 * \author Mike Becker | |
| 32 * \author Olaf Wintermann | |
| 33 * \copyright 2-Clause BSD License | |
| 34 */ | |
| 35 | |
| 36 | |
| 37 #ifndef UCX_HASH_KEY_H | |
| 38 #define UCX_HASH_KEY_H | |
| 39 | |
| 40 #include "common.h" | |
| 41 | |
| 42 #ifdef __cplusplus | |
| 43 extern "C" { | |
| 44 #endif | |
| 45 | |
| 46 /** Internal structure for a key within a hash map. */ | |
| 47 struct cx_hash_key_s { | |
| 48 /** The key data. */ | |
| 49 const void *data; | |
| 50 /** | |
| 51 * The key data length. | |
| 52 */ | |
| 53 size_t len; | |
| 54 /** The hash value of the key data. */ | |
| 55 unsigned hash; | |
| 56 }; | |
| 57 | |
| 58 /** | |
| 59 * Type for a hash key. | |
| 60 */ | |
| 61 typedef struct cx_hash_key_s CxHashKey; | |
| 62 | |
| 63 /** | |
| 64 * Computes a murmur2 32 bit hash. | |
| 65 * | |
| 66 * You need to initialize \c data and \c len in the key struct. | |
| 67 * The hash is then directly written to that struct. | |
| 68 * | |
| 69 * \note If \c data is \c NULL, the hash is defined as 1574210520. | |
| 70 * | |
| 71 * @param key the key, the hash shall be computed for | |
| 72 */ | |
| 73 void cx_hash_murmur(CxHashKey *key); | |
| 74 | |
| 75 /** | |
| 76 * Computes a hash key from a string. | |
| 77 * | |
| 78 * The string needs to be zero-terminated. | |
| 79 * | |
| 80 * @param str the string | |
| 81 * @return the hash key | |
| 82 */ | |
| 83 __attribute__((__warn_unused_result__)) | |
| 84 CxHashKey cx_hash_key_str(const char *str); | |
| 85 | |
| 86 /** | |
| 87 * Computes a hash key from a byte array. | |
| 88 * | |
| 89 * @param bytes the array | |
| 90 * @param len the length | |
| 91 * @return the hash key | |
| 92 */ | |
| 93 __attribute__((__warn_unused_result__)) | |
| 94 CxHashKey cx_hash_key_bytes( | |
| 95 const unsigned char *bytes, | |
| 96 size_t len | |
| 97 ); | |
| 98 | |
| 99 /** | |
| 100 * Computes a hash key for an arbitrary object. | |
| 101 * | |
| 102 * The computation uses the in-memory representation that might not be | |
| 103 * the same on different platforms. Therefore, this hash should not be | |
| 104 * used for data exchange with different machines. | |
| 105 * | |
| 106 * @param obj a pointer to an arbitrary object | |
| 107 * @param len the length of object in memory | |
| 108 * @return the hash key | |
| 109 */ | |
| 110 __attribute__((__warn_unused_result__)) | |
| 111 CxHashKey cx_hash_key( | |
| 112 const void *obj, | |
| 113 size_t len | |
| 114 ); | |
| 115 | |
| 116 /** | |
| 117 * Computes a hash key from a UCX string. | |
| 118 * | |
| 119 * @param str the string | |
| 120 * @return the hash key | |
| 121 */ | |
| 122 #define cx_hash_key_cxstr(str) cx_hash_key((void*)(str).ptr, (str).length) | |
| 123 | |
| 124 #ifdef __cplusplus | |
| 125 } // extern "C" | |
| 126 #endif | |
| 127 | |
| 128 #endif // UCX_HASH_KEY_H |
