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 * \version 3.0
34 * \copyright 2-Clause BSD License
35 */
36
37
38 #ifndef UCX_HASH_KEY_H
39 #define UCX_HASH_KEY_H
40
41 #include "common.h"
42
43 #ifdef __cplusplus
44 extern "C" {
45 #endif
46
47 /** Internal structure for a key within a hash map. */
48 struct cx_hash_key_s {
49 /** The key data. */
50 void const *data;
51 /**
52 * The key data length.
53 */
54 size_t len;
55 /** The hash value of the key data. */
56 unsigned hash;
57 };
58
59 /**
60 * Type for a hash key.
61 */
62 typedef struct cx_hash_key_s CxHashKey;
63
64 /**
65 * Computes a murmur2 32 bit hash.
66 *
67 * You need to initialize \c data and \c len in the key struct.
68 * The hash is then directly written to that struct.
69 *
70 * \note If \c data is \c NULL, the hash is defined as 1574210520.
71 *
72 * @param key the key, the hash shall be computed for
73 */
74 void cx_hash_murmur(CxHashKey *key);
75
76 /**
77 * Computes a hash key from a string.
78 *
79 * The string needs to be zero-terminated.
80 *
81 * @param str the string
82 * @return the hash key
83 */
84 __attribute__((__warn_unused_result__))
85 CxHashKey cx_hash_key_str(char const *str);
86
87 /**
88 * Computes a hash key from a byte array.
89 *
90 * @param bytes the array
91 * @param len the length
92 * @return the hash key
93 */
94 __attribute__((__warn_unused_result__))
95 CxHashKey cx_hash_key_bytes(
96 unsigned char const *bytes,
97 size_t len
98 );
99
100 /**
101 * Computes a hash key for an arbitrary object.
102 *
103 * The computation uses the in-memory representation that might not be
104 * the same on different platforms. Therefore, this hash should not be
105 * used for data exchange with different machines.
106 *
107 * @param obj a pointer to an arbitrary object
108 * @param len the length of object in memory
109 * @return the hash key
110 */
111 __attribute__((__warn_unused_result__))
112 CxHashKey cx_hash_key(
113 void const *obj,
114 size_t len
115 );
116
117 /**
118 * Computes a hash key from a UCX string.
119 *
120 * @param str the string
121 * @return the hash key
122 */
123 #define cx_hash_key_cxstr(str) cx_hash_key((void*)(str).ptr, (str).length)
124
125 #ifdef __cplusplus
126 } // extern "C"
127 #endif
128
129 #endif // UCX_HASH_KEY_H
130