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comparison: ucx/ucx/map.h

ucx/ucx/map.h

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1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2017 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 /**
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 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 to publicly denote a key of a UcxMap. */
93 struct UcxKey {
94 /** The key data. */
95 const void *data;
96 /** The length of the key data. */
97 size_t len;
98 /** A cache for the hash value of the key data. */
99 int hash;
100 };
101
102 /** Internal structure for a key of a UcxMap. */
103 struct UcxMapKey {
104 /** The key data. */
105 void *data;
106 /** The length of the key data. */
107 size_t len;
108 /** The hash value of the key data. */
109 int hash;
110 };
111
112 /** Structure for an element of a UcxMap. */
113 struct UcxMapElement {
114 /** The value data. */
115 void *data;
116
117 /** A pointer to the next element in the current list. */
118 UcxMapElement *next;
119
120 /** The corresponding key. */
121 struct UcxMapKey key;
122 };
123
124 /** Structure for an iterator over a UcxMap. */
125 struct UcxMapIterator {
126 /** The map to iterate over. */
127 UcxMap *map;
128
129 /** The current map element. */
130 UcxMapElement *cur;
131
132 /**
133 * The current index of the element list array.
134 * <b>Attention: </b> this is <b>NOT</b> the element index! Do <b>NOT</b>
135 * manually iterate over the map by increasing this index. Use
136 * ucx_map_iter_next().
137 * @see UcxMap.map*/
138 size_t index;
139 };
140
141 /**
142 * Creates a new hash map with the specified size.
143 * @param size the size of the hash map
144 * @return a pointer to the new hash map
145 */
146 UcxMap *ucx_map_new(size_t size);
147
148 /**
149 * Creates a new hash map with the specified size using a UcxAllocator.
150 * @param allocator the allocator to use
151 * @param size the size of the hash map
152 * @return a pointer to the new hash map
153 */
154 UcxMap *ucx_map_new_a(UcxAllocator *allocator, size_t size);
155
156 /**
157 * Frees a hash map.
158 *
159 * <b>Note:</b> the contents are <b>not</b> freed, use ucx_map_free_content()
160 * before calling this function to achieve that.
161 *
162 * @param map the map to be freed
163 * @see ucx_map_free_content()
164 */
165 void ucx_map_free(UcxMap *map);
166
167 /**
168 * Frees the contents of a hash map.
169 *
170 * This is a convenience function that iterates over the map and passes all
171 * values to the specified destructor function.
172 *
173 * If no destructor is specified (<code>NULL</code>), the free() function of
174 * the map's own allocator is used.
175 *
176 * You must ensure, that it is valid to pass each value in the map to the same
177 * destructor function.
178 *
179 * You should free or clear the map afterwards, as the contents will be invalid.
180 *
181 * @param map for which the contents shall be freed
182 * @param destr optional pointer to a destructor function
183 * @see ucx_map_free()
184 * @see ucx_map_clear()
185 */
186 void ucx_map_free_content(UcxMap *map, ucx_destructor destr);
187
188 /**
189 * Clears a hash map.
190 *
191 * <b>Note:</b> the contents are <b>not</b> freed, use ucx_map_free_content()
192 * before calling this function to achieve that.
193 *
194 * @param map the map to be cleared
195 * @see ucx_map_free_content()
196 */
197 void ucx_map_clear(UcxMap *map);
198
199
200 /**
201 * Copies contents from a map to another map using a copy function.
202 *
203 * <b>Note:</b> The destination map does not need to be empty. However, if it
204 * contains data with keys that are also present in the source map, the contents
205 * are overwritten.
206 *
207 * @param from the source map
208 * @param to the destination map
209 * @param fnc the copy function or <code>NULL</code> if the pointer address
210 * shall be copied
211 * @param data additional data for the copy function
212 * @return 0 on success or a non-zero value on memory allocation errors
213 */
214 int ucx_map_copy(UcxMap *from, UcxMap *to, copy_func fnc, void *data);
215
216 /**
217 * Clones the map and rehashes if necessary.
218 *
219 * <b>Note:</b> In contrast to ucx_map_rehash() the load factor is irrelevant.
220 * This function <i>always</i> ensures a new UcxMap.size of at least
221 * 2.5*UcxMap.count.
222 *
223 * @param map the map to clone
224 * @param fnc the copy function to use or <code>NULL</code> if the new and
225 * the old map shall share the data pointers
226 * @param data additional data for the copy function
227 * @return the cloned map
228 * @see ucx_map_copy()
229 */
230 UcxMap *ucx_map_clone(UcxMap *map, copy_func fnc, void *data);
231
232 /**
233 * Increases size of the hash map, if necessary.
234 *
235 * The load value is 0.75*UcxMap.size. If the element count exceeds the load
236 * value, the map needs to be rehashed. Otherwise no action is performed and
237 * this function simply returns 0.
238 *
239 * The rehashing process ensures, that the UcxMap.size is at least
240 * 2.5*UcxMap.count. So there is enough room for additional elements without
241 * the need of another soon rehashing.
242 *
243 * You can use this function to dramatically increase access performance.
244 *
245 * @param map the map to rehash
246 * @return 1, if a memory allocation error occurred, 0 otherwise
247 */
248 int ucx_map_rehash(UcxMap *map);
249
250 /**
251 * Puts a key/value-pair into the map.
252 *
253 * @param map the map
254 * @param key the key
255 * @param value the value
256 * @return 0 on success, non-zero value on failure
257 */
258 int ucx_map_put(UcxMap *map, UcxKey key, void *value);
259
260 /**
261 * Retrieves a value by using a key.
262 *
263 * @param map the map
264 * @param key the key
265 * @return the value
266 */
267 void* ucx_map_get(UcxMap *map, UcxKey key);
268
269 /**
270 * Removes a key/value-pair from the map by using the key.
271 *
272 * @param map the map
273 * @param key the key
274 * @return the removed value
275 */
276 void* ucx_map_remove(UcxMap *map, UcxKey key);
277
278 /**
279 * Shorthand for putting data with a sstr_t key into the map.
280 * @param map the map
281 * @param key the key
282 * @param value the value
283 * @return 0 on success, non-zero value on failure
284 * @see ucx_map_put()
285 */
286 #define ucx_map_sstr_put(map, key, value) \
287 ucx_map_put(map, ucx_key(key.ptr, key.length), (void*)value)
288
289 /**
290 * Shorthand for putting data with a C string key into the map.
291 * @param map the map
292 * @param key the key
293 * @param value the value
294 * @return 0 on success, non-zero value on failure
295 * @see ucx_map_put()
296 */
297 #define ucx_map_cstr_put(map, key, value) \
298 ucx_map_put(map, ucx_key(key, strlen(key)), (void*)value)
299
300 /**
301 * Shorthand for putting data with an integer key into the map.
302 * @param map the map
303 * @param key the key
304 * @param value the value
305 * @return 0 on success, non-zero value on failure
306 * @see ucx_map_put()
307 */
308 #define ucx_map_int_put(map, key, value) \
309 ucx_map_put(map, ucx_key(&key, sizeof(key)), (void*)value)
310
311 /**
312 * Shorthand for getting data from the map with a sstr_t key.
313 * @param map the map
314 * @param key the key
315 * @return the value
316 * @see ucx_map_get()
317 */
318 #define ucx_map_sstr_get(map, key) \
319 ucx_map_get(map, ucx_key(key.ptr, key.length))
320
321 /**
322 * Shorthand for getting data from the map with a C string key.
323 * @param map the map
324 * @param key the key
325 * @return the value
326 * @see ucx_map_get()
327 */
328 #define ucx_map_cstr_get(map, key) \
329 ucx_map_get(map, ucx_key(key, strlen(key)))
330
331 /**
332 * Shorthand for getting data from the map with an integer key.
333 * @param map the map
334 * @param key the key
335 * @return the value
336 * @see ucx_map_get()
337 */
338 #define ucx_map_int_get(map, key) \
339 ucx_map_get(map, ucx_key(&key, sizeof(int)))
340
341 /**
342 * Shorthand for removing data from the map with a sstr_t key.
343 * @param map the map
344 * @param key the key
345 * @return the removed value
346 * @see ucx_map_remove()
347 */
348 #define ucx_map_sstr_remove(map, key) \
349 ucx_map_remove(map, ucx_key(key.ptr, key.length))
350
351 /**
352 * Shorthand for removing data from the map with a C string key.
353 * @param map the map
354 * @param key the key
355 * @return the removed value
356 * @see ucx_map_remove()
357 */
358 #define ucx_map_cstr_remove(map, key) \
359 ucx_map_remove(map, ucx_key(key, strlen(key)))
360
361 /**
362 * Shorthand for removing data from the map with an integer key.
363 * @param map the map
364 * @param key the key
365 * @return the removed value
366 * @see ucx_map_remove()
367 */
368 #define ucx_map_int_remove(map, key) \
369 ucx_map_remove(map, ucx_key(&key, sizeof(key)))
370
371 /**
372 * Creates a UcxKey based on the given data.
373 *
374 * This function implicitly computes the hash.
375 *
376 * @param data the data for the key
377 * @param len the length of the data
378 * @return a UcxKey with implicitly computed hash
379 * @see ucx_hash()
380 */
381 UcxKey ucx_key(const void *data, size_t len);
382
383 /**
384 * Computes a murmur hash-2.
385 *
386 * @param data the data to hash
387 * @param len the length of the data
388 * @return the murmur hash-2 of the data
389 */
390 int ucx_hash(const char *data, size_t len);
391
392 /**
393 * Creates an iterator for a map.
394 *
395 * <b>Note:</b> A UcxMapIterator iterates over all elements in all element
396 * lists successively. Therefore the order highly depends on the key hashes and
397 * may vary under different map sizes. So generally you may <b>NOT</b> rely on
398 * the iteration order.
399 *
400 * <b>Note:</b> The iterator is <b>NOT</b> initialized. You need to call
401 * ucx_map_iter_next() at least once before accessing any information. However,
402 * it is not recommended to access the fields of a UcxMapIterator directly.
403 *
404 * @param map the map to create the iterator for
405 * @return an iterator initialized on the first element of the
406 * first element list
407 * @see ucx_map_iter_next()
408 */
409 UcxMapIterator ucx_map_iterator(UcxMap *map);
410
411 /**
412 * Proceeds to the next element of the map (if any).
413 *
414 * Subsequent calls on the same iterator proceed to the next element and
415 * store the key/value-pair into the memory specified as arguments of this
416 * function.
417 *
418 * If no further elements are found, this function returns zero and leaves the
419 * last found key/value-pair in memory.
420 *
421 * @param iterator the iterator to use
422 * @param key a pointer to the memory where to store the key
423 * @param value a pointer to the memory where to store the value
424 * @return 1, if another element was found, 0 if all elements has been processed
425 * @see ucx_map_iterator()
426 */
427 int ucx_map_iter_next(UcxMapIterator *iterator, UcxKey *key, void **value);
428
429
430 #ifdef __cplusplus
431 }
432 #endif
433
434 #endif /* UCX_MAP_H */
435

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