Wed, 02 May 2018 16:14:40 +0200
makes destructor functions for *_free_content() optional + more documentation for UcxProperties
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 */
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 */
41 #ifndef UCX_MAP_H
42 #define UCX_MAP_H
44 #include "ucx.h"
45 #include "string.h"
46 #include "allocator.h"
47 #include <stdio.h>
49 #ifdef __cplusplus
50 extern "C" {
51 #endif
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);)
68 /** Type for the UCX map. @see UcxMap */
69 typedef struct UcxMap UcxMap;
71 /** Type for a key of a UcxMap. @see UcxKey */
72 typedef struct UcxKey UcxKey;
74 /** Type for an element of a UcxMap. @see UcxMapElement */
75 typedef struct UcxMapElement UcxMapElement;
77 /** Type for an iterator over a UcxMap. @see UcxMapIterator */
78 typedef struct UcxMapIterator UcxMapIterator;
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 };
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 };
102 /** Structure for an element of a UcxMap. */
103 struct UcxMapElement {
104 /** The value data. */
105 void *data;
107 /** A pointer to the next element in the current list. */
108 UcxMapElement *next;
110 /** The corresponding key. */
111 UcxKey key;
112 };
114 /** Structure for an iterator over a UcxMap. */
115 struct UcxMapIterator {
116 /** The map to iterate over. */
117 UcxMap *map;
119 /** The current map element. */
120 UcxMapElement *cur;
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 };
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);
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);
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);
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.
162 *
163 * If no destructor is specified (<code>NULL</code>), the free() function of
164 * the map's own allocator is used.
165 *
166 * You must ensure, that it is valid to pass each value in the map to the same
167 * destructor function.
168 *
169 * You should free or clear the map afterwards, as the contents will be invalid.
170 *
171 * @param map for which the contents shall be freed
172 * @param destr optional pointer to a destructor function
173 * @see ucx_map_free()
174 * @see ucx_map_clear()
175 */
176 void ucx_map_free_content(UcxMap *map, ucx_destructor destr);
178 /**
179 * Clears a hash map.
180 *
181 * <b>Note:</b> the contents are <b>not</b> freed, use ucx_map_free_content()
182 * before calling this function to achieve that.
183 *
184 * @param map the map to be cleared
185 * @see ucx_map_free_content()
186 */
187 void ucx_map_clear(UcxMap *map);
190 /**
191 * Copies contents from a map to another map using a copy function.
192 *
193 * <b>Note:</b> The destination map does not need to be empty. However, if it
194 * contains data with keys that are also present in the source map, the contents
195 * are overwritten.
196 *
197 * @param from the source map
198 * @param to the destination map
199 * @param fnc the copy function or <code>NULL</code> if the pointer address
200 * shall be copied
201 * @param data additional data for the copy function
202 * @return 0 on success or a non-zero value on memory allocation errors
203 */
204 int ucx_map_copy(UcxMap *from, UcxMap *to, copy_func fnc, void *data);
206 /**
207 * Clones the map and rehashes if necessary.
208 *
209 * <b>Note:</b> In contrast to ucx_map_rehash() the load factor is irrelevant.
210 * This function <i>always</i> ensures a new UcxMap.size of at least
211 * 2.5*UcxMap.count.
212 *
213 * @param map the map to clone
214 * @param fnc the copy function to use or <code>NULL</code> if the new and
215 * the old map shall share the data pointers
216 * @param data additional data for the copy function
217 * @return the cloned map
218 * @see ucx_map_copy()
219 */
220 UcxMap *ucx_map_clone(UcxMap *map, copy_func fnc, void *data);
222 /**
223 * Increases size of the hash map, if necessary.
224 *
225 * The load value is 0.75*UcxMap.size. If the element count exceeds the load
226 * value, the map needs to be rehashed. Otherwise no action is performed and
227 * this function simply returns 0.
228 *
229 * The rehashing process ensures, that the UcxMap.size is at least
230 * 2.5*UcxMap.count. So there is enough room for additional elements without
231 * the need of another soon rehashing.
232 *
233 * You can use this function to dramatically increase access performance.
234 *
235 * @param map the map to rehash
236 * @return 1, if a memory allocation error occurred, 0 otherwise
237 */
238 int ucx_map_rehash(UcxMap *map);
240 /**
241 * Puts a key/value-pair into the map.
242 *
243 * @param map the map
244 * @param key the key
245 * @param value the value
246 * @return 0 on success, non-zero value on failure
247 */
248 int ucx_map_put(UcxMap *map, UcxKey key, void *value);
250 /**
251 * Retrieves a value by using a key.
252 *
253 * @param map the map
254 * @param key the key
255 * @return the value
256 */
257 void* ucx_map_get(UcxMap *map, UcxKey key);
259 /**
260 * Removes a key/value-pair from the map by using the key.
261 *
262 * @param map the map
263 * @param key the key
264 * @return the removed value
265 */
266 void* ucx_map_remove(UcxMap *map, UcxKey key);
268 /**
269 * Shorthand for putting data with a sstr_t key into the map.
270 * @param map the map
271 * @param key the key
272 * @param value the value
273 * @return 0 on success, non-zero value on failure
274 * @see ucx_map_put()
275 */
276 #define ucx_map_sstr_put(map, key, value) \
277 ucx_map_put(map, ucx_key(key.ptr, key.length), (void*)value)
279 /**
280 * Shorthand for putting data with a C string key into the map.
281 * @param map the map
282 * @param key the key
283 * @param value the value
284 * @return 0 on success, non-zero value on failure
285 * @see ucx_map_put()
286 */
287 #define ucx_map_cstr_put(map, key, value) \
288 ucx_map_put(map, ucx_key((void*)key, strlen(key)), (void*)value)
290 /**
291 * Shorthand for putting data with an integer key into the map.
292 * @param map the map
293 * @param key the key
294 * @param value the value
295 * @return 0 on success, non-zero value on failure
296 * @see ucx_map_put()
297 */
298 #define ucx_map_int_put(map, key, value) \
299 ucx_map_put(map, ucx_key((void*)&key, sizeof(key)), (void*)value)
301 /**
302 * Shorthand for getting data from the map with a sstr_t key.
303 * @param map the map
304 * @param key the key
305 * @return the value
306 * @see ucx_map_get()
307 */
308 #define ucx_map_sstr_get(map, key) \
309 ucx_map_get(map, ucx_key(key.ptr, key.length))
311 /**
312 * Shorthand for getting data from the map with a C string 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_cstr_get(map, key) \
319 ucx_map_get(map, ucx_key((void*)key, strlen(key)))
321 /**
322 * Shorthand for getting data from the map with an integer 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_int_get(map, key) \
329 ucx_map_get(map, ucx_key((void*)&key, sizeof(int)))
331 /**
332 * Shorthand for removing data from the map with a sstr_t key.
333 * @param map the map
334 * @param key the key
335 * @return the removed value
336 * @see ucx_map_remove()
337 */
338 #define ucx_map_sstr_remove(map, key) \
339 ucx_map_remove(map, ucx_key(key.ptr, key.length))
341 /**
342 * Shorthand for removing data from the map with a C string 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_cstr_remove(map, key) \
349 ucx_map_remove(map, ucx_key((void*)key, strlen(key)))
351 /**
352 * Shorthand for removing data from the map with an integer 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_int_remove(map, key) \
359 ucx_map_remove(map, ucx_key((void*)&key, sizeof(key)))
361 /**
362 * Creates a UcxKey based on the given data.
363 *
364 * This function implicitly computes the hash.
365 *
366 * @param data the data for the key
367 * @param len the length of the data
368 * @return a UcxKey with implicitly computed hash
369 * @see ucx_hash()
370 */
371 UcxKey ucx_key(void *data, size_t len);
373 /**
374 * Computes a murmur hash-2.
375 *
376 * @param data the data to hash
377 * @param len the length of the data
378 * @return the murmur hash-2 of the data
379 */
380 int ucx_hash(const char *data, size_t len);
382 /**
383 * Creates an iterator for a map.
384 *
385 * <b>Note:</b> A UcxMapIterator iterates over all elements in all element
386 * lists successively. Therefore the order highly depends on the key hashes and
387 * may vary under different map sizes. So generally you may <b>NOT</b> rely on
388 * the iteration order.
389 *
390 * <b>Note:</b> The iterator is <b>NOT</b> initialized. You need to call
391 * ucx_map_iter_next() at least once before accessing any information. However,
392 * it is not recommended to access the fields of a UcxMapIterator directly.
393 *
394 * @param map the map to create the iterator for
395 * @return an iterator initialized on the first element of the
396 * first element list
397 * @see ucx_map_iter_next()
398 */
399 UcxMapIterator ucx_map_iterator(UcxMap *map);
401 /**
402 * Proceeds to the next element of the map (if any).
403 *
404 * Subsequent calls on the same iterator proceed to the next element and
405 * store the key/value-pair into the memory specified as arguments of this
406 * function.
407 *
408 * If no further elements are found, this function returns zero and leaves the
409 * last found key/value-pair in memory.
410 *
411 * @param iterator the iterator to use
412 * @param key a pointer to the memory where to store the key
413 * @param value a pointer to the memory where to store the value
414 * @return 1, if another element was found, 0 if all elements has been processed
415 * @see ucx_map_iterator()
416 */
417 int ucx_map_iter_next(UcxMapIterator *iterator, UcxKey *key, void **value);
420 #ifdef __cplusplus
421 }
422 #endif
424 #endif /* UCX_MAP_H */