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comparison: src/ucx/map.h

src/ucx/map.h

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1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2017 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/ucx.h>
45 #include <ucx/string.h>
46 #include <ucx/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 a 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 a UcxMap. @see UcxKey */
72 typedef struct UcxKey UcxKey;
73
74 /** Type for an element of a UcxMap. @see UcxMapElement */
75 typedef struct UcxMapElement UcxMapElement;
76
77 /** Type for an iterator over a 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 a 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 a 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 a 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 a 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 ucx_map_free_content()
150 * before calling this function to achieve that.
151 *
152 * @param map the map to be freed
153 * @see ucx_map_free_content()
154 */
155 void ucx_map_free(UcxMap *map);
156
157 /**
158 * Frees the contents of a hash map.
159 *
160 * This is a convenience function that iterates over the map and passes all
161 * values to the specified destructor function (e.g. stdlib free()).
162 *
163 * You must ensure, that it is valid to pass each value in the map to the same
164 * destructor function.
165 *
166 * You should free or clear the map afterwards, as the contents will be invalid.
167 *
168 * @param map for which the contents shall be freed
169 * @param destr pointer to the destructor function
170 * @see ucx_map_free()
171 * @see ucx_map_clear()
172 */
173 void ucx_map_free_content(UcxMap *map, ucx_destructor destr);
174
175 /**
176 * Clears a hash map.
177 *
178 * <b>Note:</b> the contents are <b>not</b> freed, use ucx_map_free_content()
179 * before calling this function to achieve that.
180 *
181 * @param map the map to be cleared
182 * @see ucx_map_free_content()
183 */
184 void ucx_map_clear(UcxMap *map);
185
186
187 /**
188 * Copies contents from a map to another map using a copy function.
189 *
190 * <b>Note:</b> The destination map does not need to be empty. However, if it
191 * contains data with keys that are also present in the source map, the contents
192 * are overwritten.
193 *
194 * @param from the source map
195 * @param to the destination map
196 * @param fnc the copy function or <code>NULL</code> if the pointer address
197 * shall be copied
198 * @param data additional data for the copy function
199 * @return 0 on success or a non-zero value on memory allocation errors
200 */
201 int ucx_map_copy(UcxMap *restrict from, UcxMap *restrict to,
202 copy_func fnc, void *data);
203
204 /**
205 * Clones the map and rehashes if necessary.
206 *
207 * <b>Note:</b> In contrast to ucx_map_rehash() the load factor is irrelevant.
208 * This function <i>always</i> ensures a new UcxMap.size of at least
209 * 2.5*UcxMap.count.
210 *
211 * @param map the map to clone
212 * @param fnc the copy function to use or <code>NULL</code> if the new and
213 * the old map shall share the data pointers
214 * @param data additional data for the copy function
215 * @return the cloned map
216 * @see ucx_map_copy()
217 */
218 UcxMap *ucx_map_clone(UcxMap *map, copy_func fnc, void *data);
219
220 /**
221 * Increases size of the hash map, if necessary.
222 *
223 * The load value is 0.75*UcxMap.size. If the element count exceeds the load
224 * value, the map needs to be rehashed. Otherwise no action is performed and
225 * this function simply returns 0.
226 *
227 * The rehashing process ensures, that the UcxMap.size is at least
228 * 2.5*UcxMap.count. So there is enough room for additional elements without
229 * the need of another soon rehashing.
230 *
231 * You can use this function to dramatically increase access performance.
232 *
233 * @param map the map to rehash
234 * @return 1, if a memory allocation error occurred, 0 otherwise
235 */
236 int ucx_map_rehash(UcxMap *map);
237
238 /**
239 * Puts a key/value-pair into the map.
240 *
241 * @param map the map
242 * @param key the key
243 * @param value the value
244 * @return 0 on success, non-zero value on failure
245 */
246 int ucx_map_put(UcxMap *map, UcxKey key, void *value);
247
248 /**
249 * Retrieves a value by using a key.
250 *
251 * @param map the map
252 * @param key the key
253 * @return the value
254 */
255 void* ucx_map_get(UcxMap *map, UcxKey key);
256
257 /**
258 * Removes a key/value-pair from the map by using the key.
259 *
260 * @param map the map
261 * @param key the key
262 * @return the removed value
263 */
264 void* ucx_map_remove(UcxMap *map, UcxKey key);
265
266 /**
267 * Shorthand for putting data with a sstr_t key into the map.
268 * @param map the map
269 * @param key the key
270 * @param value the value
271 * @return 0 on success, non-zero value on failure
272 * @see ucx_map_put()
273 */
274 #define ucx_map_sstr_put(map, key, value) \
275 ucx_map_put(map, ucx_key(key.ptr, key.length), (void*)value)
276
277 /**
278 * Shorthand for putting data with a C string key into the map.
279 * @param map the map
280 * @param key the key
281 * @param value the value
282 * @return 0 on success, non-zero value on failure
283 * @see ucx_map_put()
284 */
285 #define ucx_map_cstr_put(map, key, value) \
286 ucx_map_put(map, ucx_key((void*)key, strlen(key)), (void*)value)
287
288 /**
289 * Shorthand for putting data with an integer key into the map.
290 * @param map the map
291 * @param key the key
292 * @param value the value
293 * @return 0 on success, non-zero value on failure
294 * @see ucx_map_put()
295 */
296 #define ucx_map_int_put(map, key, value) \
297 ucx_map_put(map, ucx_key((void*)&key, sizeof(key)), (void*)value)
298
299 /**
300 * Shorthand for getting data from the map with a sstr_t key.
301 * @param map the map
302 * @param key the key
303 * @return the value
304 * @see ucx_map_get()
305 */
306 #define ucx_map_sstr_get(map, key) \
307 ucx_map_get(map, ucx_key(key.ptr, key.length))
308
309 /**
310 * Shorthand for getting data from the map with a C string key.
311 * @param map the map
312 * @param key the key
313 * @return the value
314 * @see ucx_map_get()
315 */
316 #define ucx_map_cstr_get(map, key) \
317 ucx_map_get(map, ucx_key((void*)key, strlen(key)))
318
319 /**
320 * Shorthand for getting data from the map with an integer key.
321 * @param map the map
322 * @param key the key
323 * @return the value
324 * @see ucx_map_get()
325 */
326 #define ucx_map_int_get(map, key) \
327 ucx_map_get(map, ucx_key((void*)&key, sizeof(int)))
328
329 /**
330 * Shorthand for removing data from the map with a sstr_t key.
331 * @param map the map
332 * @param key the key
333 * @return the removed value
334 * @see ucx_map_remove()
335 */
336 #define ucx_map_sstr_remove(map, key) \
337 ucx_map_remove(map, ucx_key(key.ptr, key.length))
338
339 /**
340 * Shorthand for removing data from the map with a C string key.
341 * @param map the map
342 * @param key the key
343 * @return the removed value
344 * @see ucx_map_remove()
345 */
346 #define ucx_map_cstr_remove(map, key) \
347 ucx_map_remove(map, ucx_key((void*)key, strlen(key)))
348
349 /**
350 * Shorthand for removing data from the map with an integer key.
351 * @param map the map
352 * @param key the key
353 * @return the removed value
354 * @see ucx_map_remove()
355 */
356 #define ucx_map_int_remove(map, key) \
357 ucx_map_remove(map, ucx_key((void*)&key, sizeof(key)))
358
359 /**
360 * Creates a UcxKey based on the given data.
361 *
362 * This function implicitly computes the hash.
363 *
364 * @param data the data for the key
365 * @param len the length of the data
366 * @return a UcxKey with implicitly computed hash
367 * @see ucx_hash()
368 */
369 UcxKey ucx_key(void *data, size_t len);
370
371 /**
372 * Computes a murmur hash-2.
373 *
374 * @param data the data to hash
375 * @param len the length of the data
376 * @return the murmur hash-2 of the data
377 */
378 int ucx_hash(const char *data, size_t len);
379
380 /**
381 * Creates an iterator for a map.
382 *
383 * <b>Note:</b> A UcxMapIterator iterates over all elements in all element
384 * lists successively. Therefore the order highly depends on the key hashes and
385 * may vary under different map sizes. So generally you may <b>NOT</b> rely on
386 * the iteration order.
387 *
388 * <b>Note:</b> The iterator is <b>NOT</b> initialized. You need to call
389 * ucx_map_iter_next() at least once before accessing any information. However,
390 * it is not recommended to access the fields of a UcxMapIterator directly.
391 *
392 * @param map the map to create the iterator for
393 * @return an iterator initialized on the first element of the
394 * first element list
395 * @see ucx_map_iter_next()
396 */
397 UcxMapIterator ucx_map_iterator(UcxMap *map);
398
399 /**
400 * Proceeds to the next element of the map (if any).
401 *
402 * Subsequent calls on the same iterator proceed to the next element and
403 * store the key/value-pair into the memory specified as arguments of this
404 * function.
405 *
406 * If no further elements are found, this function returns zero and leaves the
407 * last found key/value-pair in memory.
408 *
409 * @param iterator the iterator to use
410 * @param key a pointer to the memory where to store the key
411 * @param value a pointer to the memory where to store the value
412 * @return 1, if another element was found, 0 if all elements has been processed
413 * @see ucx_map_iterator()
414 */
415 int ucx_map_iter_next(UcxMapIterator *iterator, UcxKey *key, void **value);
416
417
418 #ifdef __cplusplus
419 }
420 #endif
421
422 #endif /* UCX_MAP_H */
423

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