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1 | /* |
2 | * Copyright (c) 2009-2016 Petri Lehtinen <petri@digip.org> | |
3 | * | |
4 | * This library is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the MIT license. See LICENSE for details. | |
6 | */ | |
7 | ||
8 | #ifndef HASHTABLE_H | |
9 | #define HASHTABLE_H | |
10 | ||
11 | #include <stdlib.h> | |
12 | #include "jansson.h" | |
13 | ||
14 | struct hashtable_list { | |
15 | struct hashtable_list *prev; | |
16 | struct hashtable_list *next; | |
17 | }; | |
18 | ||
19 | /* "pair" may be a bit confusing a name, but think of it as a | |
20 | key-value pair. In this case, it just encodes some extra data, | |
21 | too */ | |
22 | struct hashtable_pair { | |
23 | struct hashtable_list list; | |
24 | struct hashtable_list ordered_list; | |
25 | size_t hash; | |
26 | json_t *value; | |
27 | char key[1]; | |
28 | }; | |
29 | ||
30 | struct hashtable_bucket { | |
31 | struct hashtable_list *first; | |
32 | struct hashtable_list *last; | |
33 | }; | |
34 | ||
35 | typedef struct hashtable { | |
36 | size_t size; | |
37 | struct hashtable_bucket *buckets; | |
38 | size_t order; /* hashtable has pow(2, order) buckets */ | |
39 | struct hashtable_list list; | |
40 | struct hashtable_list ordered_list; | |
41 | } hashtable_t; | |
42 | ||
43 | ||
44 | #define hashtable_key_to_iter(key_) \ | |
45 | (&(container_of(key_, struct hashtable_pair, key)->ordered_list)) | |
46 | ||
47 | ||
48 | /** | |
49 | * hashtable_init - Initialize a hashtable object | |
50 | * | |
51 | * @hashtable: The (statically allocated) hashtable object | |
52 | * | |
53 | * Initializes a statically allocated hashtable object. The object | |
54 | * should be cleared with hashtable_close when it's no longer used. | |
55 | * | |
56 | * Returns 0 on success, -1 on error (out of memory). | |
57 | */ | |
6a2bd857 | 58 | int hashtable_init(hashtable_t *hashtable) JANSSON_ATTRS(warn_unused_result); |
556826b5 OM |
59 | |
60 | /** | |
61 | * hashtable_close - Release all resources used by a hashtable object | |
62 | * | |
63 | * @hashtable: The hashtable | |
64 | * | |
65 | * Destroys a statically allocated hashtable object. | |
66 | */ | |
67 | void hashtable_close(hashtable_t *hashtable); | |
68 | ||
69 | /** | |
70 | * hashtable_set - Add/modify value in hashtable | |
71 | * | |
72 | * @hashtable: The hashtable object | |
73 | * @key: The key | |
74 | * @serial: For addition order of keys | |
75 | * @value: The value | |
76 | * | |
77 | * If a value with the given key already exists, its value is replaced | |
78 | * with the new value. Value is "stealed" in the sense that hashtable | |
79 | * doesn't increment its refcount but decreases the refcount when the | |
80 | * value is no longer needed. | |
81 | * | |
82 | * Returns 0 on success, -1 on failure (out of memory). | |
83 | */ | |
84 | int hashtable_set(hashtable_t *hashtable, const char *key, json_t *value); | |
85 | ||
86 | /** | |
87 | * hashtable_get - Get a value associated with a key | |
88 | * | |
89 | * @hashtable: The hashtable object | |
90 | * @key: The key | |
91 | * | |
92 | * Returns value if it is found, or NULL otherwise. | |
93 | */ | |
94 | void *hashtable_get(hashtable_t *hashtable, const char *key); | |
95 | ||
96 | /** | |
97 | * hashtable_del - Remove a value from the hashtable | |
98 | * | |
99 | * @hashtable: The hashtable object | |
100 | * @key: The key | |
101 | * | |
102 | * Returns 0 on success, or -1 if the key was not found. | |
103 | */ | |
104 | int hashtable_del(hashtable_t *hashtable, const char *key); | |
105 | ||
106 | /** | |
107 | * hashtable_clear - Clear hashtable | |
108 | * | |
109 | * @hashtable: The hashtable object | |
110 | * | |
111 | * Removes all items from the hashtable. | |
112 | */ | |
113 | void hashtable_clear(hashtable_t *hashtable); | |
114 | ||
115 | /** | |
116 | * hashtable_iter - Iterate over hashtable | |
117 | * | |
118 | * @hashtable: The hashtable object | |
119 | * | |
120 | * Returns an opaque iterator to the first element in the hashtable. | |
121 | * The iterator should be passed to hashtable_iter_* functions. | |
122 | * The hashtable items are not iterated over in any particular order. | |
123 | * | |
124 | * There's no need to free the iterator in any way. The iterator is | |
125 | * valid as long as the item that is referenced by the iterator is not | |
126 | * deleted. Other values may be added or deleted. In particular, | |
127 | * hashtable_iter_next() may be called on an iterator, and after that | |
128 | * the key/value pair pointed by the old iterator may be deleted. | |
129 | */ | |
130 | void *hashtable_iter(hashtable_t *hashtable); | |
131 | ||
132 | /** | |
133 | * hashtable_iter_at - Return an iterator at a specific key | |
134 | * | |
135 | * @hashtable: The hashtable object | |
136 | * @key: The key that the iterator should point to | |
137 | * | |
138 | * Like hashtable_iter() but returns an iterator pointing to a | |
139 | * specific key. | |
140 | */ | |
141 | void *hashtable_iter_at(hashtable_t *hashtable, const char *key); | |
142 | ||
143 | /** | |
144 | * hashtable_iter_next - Advance an iterator | |
145 | * | |
146 | * @hashtable: The hashtable object | |
147 | * @iter: The iterator | |
148 | * | |
149 | * Returns a new iterator pointing to the next element in the | |
150 | * hashtable or NULL if the whole hastable has been iterated over. | |
151 | */ | |
152 | void *hashtable_iter_next(hashtable_t *hashtable, void *iter); | |
153 | ||
154 | /** | |
155 | * hashtable_iter_key - Retrieve the key pointed by an iterator | |
156 | * | |
157 | * @iter: The iterator | |
158 | */ | |
159 | void *hashtable_iter_key(void *iter); | |
160 | ||
161 | /** | |
162 | * hashtable_iter_value - Retrieve the value pointed by an iterator | |
163 | * | |
164 | * @iter: The iterator | |
165 | */ | |
166 | void *hashtable_iter_value(void *iter); | |
167 | ||
168 | /** | |
169 | * hashtable_iter_set - Set the value pointed by an iterator | |
170 | * | |
171 | * @iter: The iterator | |
172 | * @value: The value to set | |
173 | */ | |
174 | void hashtable_iter_set(void *iter, json_t *value); | |
175 | ||
176 | #endif |