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
129