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comparison: ucx/map.h

ucx/map.h

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1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2013 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 /**
30 * @file map.h
31 *
32 * Hash map implementation.
33 *
34 * This implementation uses murmur hash 2 and separate chaining with linked
35 * lists.
36 *
37 * @author Mike Becker
38 * @author Olaf Wintermann
39 */
40
41 #ifndef UCX_MAP_H
42 #define UCX_MAP_H
43
44 #include "ucx.h"
45 #include "string.h"
46 #include "allocator.h"
47 #include <stdio.h>
48
49 #ifdef __cplusplus
50 extern "C" {
51 #endif
52
53 /**
54 * Loop statement for UCX maps.
55 *
56 * The <code>key</code> variable is implicitly defined, but the
57 * <code>value</code> variable must be already declared as type information
58 * cannot be inferred.
59 *
60 * @param key the variable name for the key
61 * @param value the variable name for the value
62 * @param iter an UcxMapIterator
63 * @see ucx_map_iterator()
64 */
65 #define UCX_MAP_FOREACH(key,value,iter) \
66 for(UcxKey key;ucx_map_iter_next(&iter,&key, (void**)&value);)
67
68 /** Type for the UCX map. @see UcxMap */
69 typedef struct UcxMap UcxMap;
70
71 /** Type for a key of an UcxMap. @see UcxKey */
72 typedef struct UcxKey UcxKey;
73
74 /** Type for an element of an UcxMap. @see UcxMapElement */
75 typedef struct UcxMapElement UcxMapElement;
76
77 /** Type for an iterator over an UcxMap. @see UcxMapIterator */
78 typedef struct UcxMapIterator UcxMapIterator;
79
80 /** Structure for the UCX map. */
81 struct UcxMap {
82 /** An allocator that is used for the map elements. */
83 UcxAllocator *allocator;
84 /** The array of map element lists. */
85 UcxMapElement **map;
86 /** The size of the map is the length of the element list array. */
87 size_t size;
88 /** The count of elements currently stored in this map. */
89 size_t count;
90 };
91
92 /** Structure for a key of an UcxMap. */
93 struct UcxKey {
94 /** The key data. */
95 void *data;
96 /** The length of the key data. */
97 size_t len;
98 /** The hash value of the key data. */
99 int hash;
100 };
101
102 /** Structure for an element of an UcxMap. */
103 struct UcxMapElement {
104 /** The value data. */
105 void *data;
106
107 /** A pointer to the next element in the current list. */
108 UcxMapElement *next;
109
110 /** The corresponding key. */
111 UcxKey key;
112 };
113
114 /** Structure for an iterator over an UcxMap. */
115 struct UcxMapIterator {
116 /** The map to iterate over. */
117 UcxMap *map;
118
119 /** The current map element. */
120 UcxMapElement *cur;
121
122 /**
123 * The current index of the element list array.
124 * <b>Attention: </b> this is <b>NOT</b> the element index! Do <b>NOT</b>
125 * manually iterate over the map by increasing this index. Use
126 * ucx_map_iter_next().
127 * @see UcxMap.map*/
128 size_t index;
129 };
130
131 /**
132 * Creates a new hash map with the specified size.
133 * @param size the size of the hash map
134 * @return a pointer to the new hash map
135 */
136 UcxMap *ucx_map_new(size_t size);
137
138 /**
139 * Creates a new hash map with the specified size using an UcxAllocator.
140 * @param allocator the allocator to use
141 * @param size the size of the hash map
142 * @return a pointer to the new hash map
143 */
144 UcxMap *ucx_map_new_a(UcxAllocator *allocator, size_t size);
145
146 /**
147 * Frees a hash map.
148 *
149 * <b>Note:</b> the contents are <b>not</b> freed, use an UcxMempool for that
150 * purpose.
151 *
152 * @param map the map to be freed
153 */
154 void ucx_map_free(UcxMap *map);
155
156 /**
157 * Copies contents from a map to another map using a copy function.
158 *
159 * <b>Note:</b> The destination map does not need to be empty. However, if it
160 * contains data with keys that are also present in the source map, the contents
161 * are overwritten.
162 *
163 * @param from the source map
164 * @param to the destination map
165 * @param fnc the copy function or <code>NULL</code> if the pointer address
166 * shall be copied
167 * @param data additional data for the copy function
168 * @return 0 on success or a non-zero value on memory allocation errors
169 */
170 int ucx_map_copy(UcxMap *restrict from, UcxMap *restrict to,
171 copy_func fnc, void *data);
172
173 /**
174 * Clones the map and rehashes if necessary.
175 *
176 * <b>Note:</b> In contrast to ucx_map_rehash() the load factor is irrelevant.
177 * This function <i>always</i> ensures a new UcxMap.size of at least
178 * 2.5*UcxMap.count.
179 *
180 * @param map the map to clone
181 * @param fnc the copy function to use or <code>NULL</code> if the new and
182 * the old map shall share the data pointers
183 * @param data additional data for the copy function
184 * @return the cloned map
185 * @see ucx_map_copy()
186 */
187 UcxMap *ucx_map_clone(UcxMap *map, copy_func fnc, void *data);
188
189 /**
190 * Increases size of the hash map, if necessary.
191 *
192 * The load value is 0.75*UcxMap.size. If the element count exceeds the load
193 * value, the map needs to be rehashed. Otherwise no action is performed and
194 * this function simply returns 0.
195 *
196 * The rehashing process ensures, that the UcxMap.size is at least
197 * 2.5*UcxMap.count. So there is enough room for additional elements without
198 * the need of another soon rehashing.
199 *
200 * You can use this function to dramatically increase access performance.
201 *
202 * @param map the map to rehash
203 * @return 1, if a memory allocation error occurred, 0 otherwise
204 */
205 int ucx_map_rehash(UcxMap *map);
206
207 /**
208 * Puts a key/value-pair into the map.
209 *
210 * @param map the map
211 * @param key the key
212 * @param value the value
213 * @return 0 on success, non-zero value on failure
214 */
215 int ucx_map_put(UcxMap *map, UcxKey key, void *value);
216
217 /**
218 * Retrieves a value by using a key.
219 *
220 * @param map the map
221 * @param key the key
222 * @return the value
223 */
224 void* ucx_map_get(UcxMap *map, UcxKey key);
225
226 /**
227 * Removes a key/value-pair from the map by using the key.
228 *
229 * @param map the map
230 * @param key the key
231 * @return the removed value
232 */
233 void* ucx_map_remove(UcxMap *map, UcxKey key);
234
235 /**
236 * Shorthand for putting data with a sstr_t key into the map.
237 * @param map the map
238 * @param key the key
239 * @param value the value
240 * @return 0 on success, non-zero value on failure
241 * @see ucx_map_put()
242 */
243 #define ucx_map_sstr_put(map, key, value) \
244 ucx_map_put(map, ucx_key(key.ptr, key.length), (void*)value)
245
246 /**
247 * Shorthand for putting data with a C string key into the map.
248 * @param map the map
249 * @param key the key
250 * @param value the value
251 * @return 0 on success, non-zero value on failure
252 * @see ucx_map_put()
253 */
254 #define ucx_map_cstr_put(map, key, value) \
255 ucx_map_put(map, ucx_key((void*)key, strlen(key)), (void*)value)
256
257 /**
258 * Shorthand for putting data with an integer key into the map.
259 * @param map the map
260 * @param key the key
261 * @param value the value
262 * @return 0 on success, non-zero value on failure
263 * @see ucx_map_put()
264 */
265 #define ucx_map_int_put(map, key, value) \
266 ucx_map_put(map, ucx_key((void*)&key, sizeof(key)), (void*)value)
267
268 /**
269 * Shorthand for getting data from the map with a sstr_t key.
270 * @param map the map
271 * @param key the key
272 * @return the value
273 * @see ucx_map_get()
274 */
275 #define ucx_map_sstr_get(map, key) \
276 ucx_map_get(map, ucx_key(key.ptr, key.length))
277
278 /**
279 * Shorthand for getting data from the map with a C string key.
280 * @param map the map
281 * @param key the key
282 * @return the value
283 * @see ucx_map_get()
284 */
285 #define ucx_map_cstr_get(map, key) \
286 ucx_map_get(map, ucx_key((void*)key, strlen(key)))
287
288 /**
289 * Shorthand for getting data from the map with an integer key.
290 * @param map the map
291 * @param key the key
292 * @return the value
293 * @see ucx_map_get()
294 */
295 #define ucx_map_int_get(map, key) \
296 ucx_map_get(map, ucx_key((void*)&key, sizeof(int)))
297
298 /**
299 * Shorthand for removing data from the map with a sstr_t key.
300 * @param map the map
301 * @param key the key
302 * @return the removed value
303 * @see ucx_map_remove()
304 */
305 #define ucx_map_sstr_remove(map, key) \
306 ucx_map_remove(map, ucx_key(key.ptr, key.length))
307
308 /**
309 * Shorthand for removing data from the map with a C string key.
310 * @param map the map
311 * @param key the key
312 * @return the removed value
313 * @see ucx_map_remove()
314 */
315 #define ucx_map_cstr_remove(map, key) \
316 ucx_map_remove(map, ucx_key((void*)key, strlen(key)))
317
318 /**
319 * Shorthand for removing data from the map with an integer key.
320 * @param map the map
321 * @param key the key
322 * @return the removed value
323 * @see ucx_map_remove()
324 */
325 #define ucx_map_int_remove(map, key) \
326 ucx_map_remove(map, ucx_key((void*)&key, sizeof(key)))
327
328 /**
329 * Creates an UcxKey based on the given data.
330 *
331 * This function implicitly computes the hash.
332 *
333 * @param data the data for the key
334 * @param len the length of the data
335 * @return an UcxKey with implicitly computed hash
336 * @see ucx_hash()
337 */
338 UcxKey ucx_key(void *data, size_t len);
339
340 /**
341 * Computes a murmur hash-2.
342 *
343 * @param data the data to hash
344 * @param len the length of the data
345 * @return the murmur hash-2 of the data
346 */
347 int ucx_hash(const char *data, size_t len);
348
349 /**
350 * Creates an iterator for a map.
351 *
352 * <b>Note:</b> An UcxMapIterator iterates over all elements in all element
353 * lists successively. Therefore the order highly depends on the key hashes and
354 * may vary under different map sizes. So generally you may <b>NOT</b> rely on
355 * the iteration order.
356 *
357 * <b>Note:</b> The iterator is <b>NOT</b> initialized. You need to call
358 * ucx_map_iter_next() at least once before accessing any information. However,
359 * it is not recommended to access the fields of an UcxMapIterator directly.
360 *
361 * @param map the map to create the iterator for
362 * @return an iterator initialized on the first element of the
363 * first element list
364 * @see ucx_map_iter_next()
365 */
366 UcxMapIterator ucx_map_iterator(UcxMap *map);
367
368 /**
369 * Proceeds to the next element of the map (if any).
370 *
371 * Subsequent calls on the same iterator proceed to the next element and
372 * store the key/value-pair into the memory specified as arguments of this
373 * function.
374 *
375 * If no further elements are found, this function returns zero and leaves the
376 * last found key/value-pair in memory.
377 *
378 * @param iterator the iterator to use
379 * @param key a pointer to the memory where to store the key
380 * @param value a pointer to the memory where to store the value
381 * @return 1, if another element was found, 0 if all elements has been processed
382 * @see ucx_map_iterator()
383 */
384 int ucx_map_iter_next(UcxMapIterator *iterator, UcxKey *key, void **value);
385
386
387 #ifdef __cplusplus
388 }
389 #endif
390
391 #endif /* UCX_MAP_H */
392

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