Thu, 15 Oct 2015 14:21:38 +0200
added convenience function ucx_map_free_contents()
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2015 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 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);)
68 /** Type for the UCX map. @see UcxMap */
69 typedef struct UcxMap UcxMap;
71 /** Type for a key of an UcxMap. @see UcxKey */
72 typedef struct UcxKey UcxKey;
74 /** Type for an element of an UcxMap. @see UcxMapElement */
75 typedef struct UcxMapElement UcxMapElement;
77 /** Type for an iterator over an 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 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 };
102 /** Structure for an element of an 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 an 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 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);
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 standard library free() function.
162 *
163 * You must ensure, that it is valid to pass each value in the map to free().
164 *
165 * You should free or clear the map afterwards, as the contents will be invalid.
166 *
167 * @param map for which the contents shall be freed
168 * @see ucx_map_free()
169 * @see ucx_map_clear()
170 */
171 void ucx_map_free_content(UcxMap *map);
173 /**
174 * Clears a hash map.
175 *
176 * <b>Note:</b> the contents are <b>not</b> freed, use ucx_map_free_content()
177 * before calling this function to achieve that.
178 *
179 * @param map the map to be cleared
180 * @see ucx_map_free_content()
181 */
182 void ucx_map_clear(UcxMap *map);
185 /**
186 * Copies contents from a map to another map using a copy function.
187 *
188 * <b>Note:</b> The destination map does not need to be empty. However, if it
189 * contains data with keys that are also present in the source map, the contents
190 * are overwritten.
191 *
192 * @param from the source map
193 * @param to the destination map
194 * @param fnc the copy function or <code>NULL</code> if the pointer address
195 * shall be copied
196 * @param data additional data for the copy function
197 * @return 0 on success or a non-zero value on memory allocation errors
198 */
199 int ucx_map_copy(UcxMap *restrict from, UcxMap *restrict to,
200 copy_func fnc, void *data);
202 /**
203 * Clones the map and rehashes if necessary.
204 *
205 * <b>Note:</b> In contrast to ucx_map_rehash() the load factor is irrelevant.
206 * This function <i>always</i> ensures a new UcxMap.size of at least
207 * 2.5*UcxMap.count.
208 *
209 * @param map the map to clone
210 * @param fnc the copy function to use or <code>NULL</code> if the new and
211 * the old map shall share the data pointers
212 * @param data additional data for the copy function
213 * @return the cloned map
214 * @see ucx_map_copy()
215 */
216 UcxMap *ucx_map_clone(UcxMap *map, copy_func fnc, void *data);
218 /**
219 * Increases size of the hash map, if necessary.
220 *
221 * The load value is 0.75*UcxMap.size. If the element count exceeds the load
222 * value, the map needs to be rehashed. Otherwise no action is performed and
223 * this function simply returns 0.
224 *
225 * The rehashing process ensures, that the UcxMap.size is at least
226 * 2.5*UcxMap.count. So there is enough room for additional elements without
227 * the need of another soon rehashing.
228 *
229 * You can use this function to dramatically increase access performance.
230 *
231 * @param map the map to rehash
232 * @return 1, if a memory allocation error occurred, 0 otherwise
233 */
234 int ucx_map_rehash(UcxMap *map);
236 /**
237 * Puts a key/value-pair into the map.
238 *
239 * @param map the map
240 * @param key the key
241 * @param value the value
242 * @return 0 on success, non-zero value on failure
243 */
244 int ucx_map_put(UcxMap *map, UcxKey key, void *value);
246 /**
247 * Retrieves a value by using a key.
248 *
249 * @param map the map
250 * @param key the key
251 * @return the value
252 */
253 void* ucx_map_get(UcxMap *map, UcxKey key);
255 /**
256 * Removes a key/value-pair from the map by using the key.
257 *
258 * @param map the map
259 * @param key the key
260 * @return the removed value
261 */
262 void* ucx_map_remove(UcxMap *map, UcxKey key);
264 /**
265 * Shorthand for putting data with a sstr_t key into the map.
266 * @param map the map
267 * @param key the key
268 * @param value the value
269 * @return 0 on success, non-zero value on failure
270 * @see ucx_map_put()
271 */
272 #define ucx_map_sstr_put(map, key, value) \
273 ucx_map_put(map, ucx_key(key.ptr, key.length), (void*)value)
275 /**
276 * Shorthand for putting data with a C string key into the map.
277 * @param map the map
278 * @param key the key
279 * @param value the value
280 * @return 0 on success, non-zero value on failure
281 * @see ucx_map_put()
282 */
283 #define ucx_map_cstr_put(map, key, value) \
284 ucx_map_put(map, ucx_key((void*)key, strlen(key)), (void*)value)
286 /**
287 * Shorthand for putting data with an integer key into the map.
288 * @param map the map
289 * @param key the key
290 * @param value the value
291 * @return 0 on success, non-zero value on failure
292 * @see ucx_map_put()
293 */
294 #define ucx_map_int_put(map, key, value) \
295 ucx_map_put(map, ucx_key((void*)&key, sizeof(key)), (void*)value)
297 /**
298 * Shorthand for getting data from the map with a sstr_t key.
299 * @param map the map
300 * @param key the key
301 * @return the value
302 * @see ucx_map_get()
303 */
304 #define ucx_map_sstr_get(map, key) \
305 ucx_map_get(map, ucx_key(key.ptr, key.length))
307 /**
308 * Shorthand for getting data from the map with a C string key.
309 * @param map the map
310 * @param key the key
311 * @return the value
312 * @see ucx_map_get()
313 */
314 #define ucx_map_cstr_get(map, key) \
315 ucx_map_get(map, ucx_key((void*)key, strlen(key)))
317 /**
318 * Shorthand for getting data from the map with an integer key.
319 * @param map the map
320 * @param key the key
321 * @return the value
322 * @see ucx_map_get()
323 */
324 #define ucx_map_int_get(map, key) \
325 ucx_map_get(map, ucx_key((void*)&key, sizeof(int)))
327 /**
328 * Shorthand for removing data from the map with a sstr_t key.
329 * @param map the map
330 * @param key the key
331 * @return the removed value
332 * @see ucx_map_remove()
333 */
334 #define ucx_map_sstr_remove(map, key) \
335 ucx_map_remove(map, ucx_key(key.ptr, key.length))
337 /**
338 * Shorthand for removing data from the map with a C string key.
339 * @param map the map
340 * @param key the key
341 * @return the removed value
342 * @see ucx_map_remove()
343 */
344 #define ucx_map_cstr_remove(map, key) \
345 ucx_map_remove(map, ucx_key((void*)key, strlen(key)))
347 /**
348 * Shorthand for removing data from the map with an integer key.
349 * @param map the map
350 * @param key the key
351 * @return the removed value
352 * @see ucx_map_remove()
353 */
354 #define ucx_map_int_remove(map, key) \
355 ucx_map_remove(map, ucx_key((void*)&key, sizeof(key)))
357 /**
358 * Creates an UcxKey based on the given data.
359 *
360 * This function implicitly computes the hash.
361 *
362 * @param data the data for the key
363 * @param len the length of the data
364 * @return an UcxKey with implicitly computed hash
365 * @see ucx_hash()
366 */
367 UcxKey ucx_key(void *data, size_t len);
369 /**
370 * Computes a murmur hash-2.
371 *
372 * @param data the data to hash
373 * @param len the length of the data
374 * @return the murmur hash-2 of the data
375 */
376 int ucx_hash(const char *data, size_t len);
378 /**
379 * Creates an iterator for a map.
380 *
381 * <b>Note:</b> An UcxMapIterator iterates over all elements in all element
382 * lists successively. Therefore the order highly depends on the key hashes and
383 * may vary under different map sizes. So generally you may <b>NOT</b> rely on
384 * the iteration order.
385 *
386 * <b>Note:</b> The iterator is <b>NOT</b> initialized. You need to call
387 * ucx_map_iter_next() at least once before accessing any information. However,
388 * it is not recommended to access the fields of an UcxMapIterator directly.
389 *
390 * @param map the map to create the iterator for
391 * @return an iterator initialized on the first element of the
392 * first element list
393 * @see ucx_map_iter_next()
394 */
395 UcxMapIterator ucx_map_iterator(UcxMap *map);
397 /**
398 * Proceeds to the next element of the map (if any).
399 *
400 * Subsequent calls on the same iterator proceed to the next element and
401 * store the key/value-pair into the memory specified as arguments of this
402 * function.
403 *
404 * If no further elements are found, this function returns zero and leaves the
405 * last found key/value-pair in memory.
406 *
407 * @param iterator the iterator to use
408 * @param key a pointer to the memory where to store the key
409 * @param value a pointer to the memory where to store the value
410 * @return 1, if another element was found, 0 if all elements has been processed
411 * @see ucx_map_iterator()
412 */
413 int ucx_map_iter_next(UcxMapIterator *iterator, UcxKey *key, void **value);
416 #ifdef __cplusplus
417 }
418 #endif
420 #endif /* UCX_MAP_H */