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1 /* |
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2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. |
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3 * |
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4 * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved. |
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5 * |
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6 * Redistribution and use in source and binary forms, with or without |
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7 * modification, are permitted provided that the following conditions are met: |
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8 * |
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9 * 1. Redistributions of source code must retain the above copyright |
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10 * notice, this list of conditions and the following disclaimer. |
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11 * |
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12 * 2. Redistributions in binary form must reproduce the above copyright |
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13 * notice, this list of conditions and the following disclaimer in the |
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14 * documentation and/or other materials provided with the distribution. |
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15 * |
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16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE |
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20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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26 * POSSIBILITY OF SUCH DAMAGE. |
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27 */ |
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28 /** |
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29 * \file hash_key.h |
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30 * \brief Interface for map implementations. |
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31 * \author Mike Becker |
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32 * \author Olaf Wintermann |
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33 * \version 3.0 |
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34 * \copyright 2-Clause BSD License |
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35 */ |
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36 |
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37 |
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38 #ifndef UCX_HASH_KEY_H |
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39 #define UCX_HASH_KEY_H |
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40 |
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41 #include "stddef.h" |
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42 |
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43 #ifdef __cplusplus |
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44 extern "C" { |
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45 #endif |
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46 |
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47 /** Internal structure for a key within a hash map. */ |
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48 struct cx_hash_key_s { |
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49 /** The key data. */ |
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50 union { |
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51 unsigned char *bytes; |
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52 unsigned char const *cbytes; |
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53 char const *cstr; |
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54 char *str; |
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55 void *obj; |
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56 } data; |
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57 /** |
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58 * The key data length. |
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59 */ |
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60 size_t len; |
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61 /** The hash value of the key data. */ |
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62 unsigned hash; |
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63 }; |
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64 |
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65 /** |
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66 * Type for a hash key. |
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67 */ |
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68 typedef struct cx_hash_key_s CxHashKey; |
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69 |
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70 /** |
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71 * Computes a murmur hash-2. |
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72 * |
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73 * You need to initialize data and len in the key struct. |
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74 * The hash is then directly written to that struct. |
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75 * |
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76 * @param key the key, the hash shall be computed for |
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77 */ |
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78 void cx_hash_murmur(CxHashKey *key); |
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79 |
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80 /** |
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81 * Computes a hash key from a string. |
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82 * |
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83 * The string needs to be zero-terminated. |
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84 * |
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85 * @param str the string |
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86 * @return the hash key |
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87 */ |
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88 __attribute__((__warn_unused_result__)) |
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89 CxHashKey cx_hash_key_str(char const *str); |
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90 |
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91 /** |
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92 * Computes a hash key from a byte array. |
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93 * |
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94 * @param bytes the array |
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95 * @param len the length |
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96 * @return the hash key |
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97 */ |
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98 __attribute__((__warn_unused_result__)) |
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99 CxHashKey cx_hash_key_bytes( |
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100 unsigned char const *bytes, |
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101 size_t len |
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102 ); |
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103 |
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104 /** |
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105 * Computes a hash key for an arbitrary object. |
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106 * |
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107 * The computation uses the in-memory representation that might not be |
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108 * the same on different platforms. Therefore, this hash should not be |
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109 * used for data exchange with different machines. |
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110 * |
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111 * @param obj a pointer to an arbitrary object |
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112 * @param len the length of object in memory |
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113 * @return the hash key |
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114 */ |
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115 __attribute__((__warn_unused_result__)) |
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116 CxHashKey cx_hash_key( |
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117 void *obj, |
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118 size_t len |
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119 ); |
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120 |
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121 #ifdef __cplusplus |
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122 } // extern "C" |
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123 #endif |
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124 |
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125 #endif /* UCX_HASH_KEY_H */ |