1 /* dict - a generic dictionary, variation over hash table */
3 /* Copyright (c) 2004-2023. The SimGrid Team. All rights reserved. */
5 /* This program is free software; you can redistribute it and/or modify it
6 * under the terms of the license (GNU LGPL) which comes with this package. */
9 #include "dict_private.h"
10 #include "simgrid/Exception.hpp"
13 #include "xbt/mallocator.h"
15 #include "xbt/string.hpp"
22 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_dict, xbt, "Dictionaries provide the same functionalities as hash tables");
24 constexpr int MAX_FILL_PERCENT = 80;
26 /** Handle the dict mallocators init/fini cycle. */
27 static void xbt_dict_postexit()
29 if (dict_elm_mallocator != nullptr) {
30 xbt_mallocator_free(dict_elm_mallocator);
31 dict_elm_mallocator = nullptr;
34 static void xbt_dict_preinit()
36 static std::mutex init_mutex;
37 const std::scoped_lock lock(init_mutex);
38 if (dict_elm_mallocator == nullptr) {
40 xbt_mallocator_new(256, dict_elm_mallocator_new_f, dict_elm_mallocator_free_f, dict_elm_mallocator_reset_f);
41 atexit(xbt_dict_postexit);
47 * @param free_ctn function to call with (@a data as argument) when @a data is removed from the dictionary
48 * @return pointer to the destination
49 * @see xbt_dict_free()
51 * Creates and initialize a new dictionary with a default hashtable size.
52 * The dictionary is homogeneous: each element share the same free function.
54 xbt_dict_t xbt_dict_new_homogeneous(void_f_pvoid_t free_ctn)
56 xbt_dict_preinit(); // Make sure that the module is intialized
60 dict = xbt_new(s_xbt_dict_t, 1);
61 dict->free_f = free_ctn;
62 dict->table_size = 127;
63 dict->table = xbt_new0(xbt_dictelm_t, dict->table_size + 1);
72 * @param dict the dictionary to be freed
74 * Frees a dictionary with all the data
76 void xbt_dict_free(xbt_dict_t * dict)
78 if (dict != nullptr && *dict != nullptr) {
79 int table_size = (*dict)->table_size;
80 xbt_dictelm_t* table = (*dict)->table;
81 /* Warning: the size of the table is 'table_size+1'...
82 * This is because table_size is used as a binary mask in xbt_dict_rehash */
83 for (int i = 0; (*dict)->count && i <= table_size; i++) {
84 xbt_dictelm_t current = table[i];
85 xbt_dictelm_t previous;
87 while (current != nullptr) {
89 current = current->next;
90 xbt_dictelm_free(*dict, previous);
100 /** Returns the amount of elements in the dict */
101 unsigned int xbt_dict_size(const_xbt_dict_t dict)
103 return (dict != nullptr ? static_cast<unsigned int>(dict->count) : static_cast<unsigned int>(0));
106 /* Expend the size of the dict */
107 static void xbt_dict_rehash(xbt_dict_t dict)
109 const unsigned oldsize = dict->table_size + 1;
110 unsigned newsize = oldsize * 2;
112 auto* newtable = static_cast<xbt_dictelm_t*>(xbt_realloc(dict->table, newsize * sizeof(xbt_dictelm_t)));
113 std::fill(newtable + oldsize, newtable + newsize, nullptr); /* zero second half */
115 dict->table_size = newsize;
116 dict->table = newtable;
117 XBT_DEBUG("REHASH (%u->%u)", oldsize, newsize);
119 for (unsigned i = 0; i < oldsize; i++) {
120 xbt_dictelm_t* currcell = &newtable[i];
121 if (*currcell == nullptr) /* empty cell */
124 xbt_dictelm_t *twincell = currcell + oldsize;
125 xbt_dictelm_t *pprev = currcell;
126 xbt_dictelm_t bucklet = *currcell;
127 while (bucklet != nullptr) {
128 /* Since we use "& size" instead of "%size" and since the size was doubled, each bucklet of this cell must either:
129 - stay in cell i (ie, currcell)
130 - go to the cell i+oldsize (ie, twincell) */
131 if ((bucklet->hash_code & newsize) != i) { /* Move to b */
132 *pprev = bucklet->next;
133 bucklet->next = *twincell;
134 if (*twincell == nullptr)
138 pprev = &bucklet->next;
143 if (*currcell == nullptr) /* everything moved */
149 * @brief Add data to the dict (arbitrary key)
150 * @param dict the container
151 * @param key the key to set the new data
152 * @param key_len the size of the @a key
153 * @param data the data to add in the dict
155 * Set the @a data in the structure under the @a key, which can be any kind of data, as long as its length is provided
158 void xbt_dict_set_ext(xbt_dict_t dict, const char* key, int key_len, void* data)
160 unsigned int hash_code = xbt_str_hash_ext(key, key_len);
162 xbt_dictelm_t current;
163 xbt_dictelm_t previous = nullptr;
165 XBT_CDEBUG(xbt_dict, "ADD %.*s hash = %u, size = %d, & = %u", key_len, key, hash_code,
166 dict->table_size, hash_code & dict->table_size);
167 current = dict->table[hash_code & dict->table_size];
168 while (current != nullptr && (hash_code != current->hash_code || key_len != current->key_len
169 || memcmp(key, current->key, key_len))) {
171 current = current->next;
174 if (current == nullptr) {
175 /* this key doesn't exist yet */
176 current = xbt_dictelm_new(key, key_len, hash_code, data);
178 if (previous == nullptr) {
179 dict->table[hash_code & dict->table_size] = current;
181 if ((dict->fill * 100) / (dict->table_size + 1) > MAX_FILL_PERCENT)
182 xbt_dict_rehash(dict);
184 previous->next = current;
187 XBT_CDEBUG(xbt_dict, "Replace %.*s by %.*s under key %.*s",
188 key_len, (char *) current->content, key_len, (char *) data, key_len, (char *) key);
189 /* there is already an element with the same key: overwrite it */
190 xbt_dictelm_set_data(dict, current, data);
195 * @brief Add data to the dict (null-terminated key)
197 * @param dict the dict
198 * @param key the key to set the new data
199 * @param data the data to add in the dict
201 * set the @a data in the structure under the @a key, which is a null terminated string.
203 void xbt_dict_set(xbt_dict_t dict, const char* key, void* data)
205 xbt_dict_set_ext(dict, key, strlen(key), data);
209 * @brief Retrieve data from the dict (arbitrary key)
211 * @param dict the dealer of data
212 * @param key the key to find data
213 * @param key_len the size of the @a key
214 * @return the data that we are looking for
216 * Search the given @a key. Returns nullptr when not found.
218 void* xbt_dict_get_or_null_ext(const_xbt_dict_t dict, const char* key, int key_len)
220 unsigned int hash_code = xbt_str_hash_ext(key, key_len);
221 const s_xbt_dictelm* current = dict->table[hash_code & dict->table_size];
223 while (current != nullptr && (hash_code != current->hash_code || key_len != current->key_len
224 || memcmp(key, current->key, key_len))) {
225 current = current->next;
228 if (current == nullptr)
231 return current->content;
235 * @brief Retrieve data from the dict (null-terminated key)
237 * @param dict the dealer of data
238 * @param key the key to find data
239 * @return the data that we are looking for
241 * Search the given @a key. Returns nullptr when not found.
243 void* xbt_dict_get_or_null(const_xbt_dict_t dict, const char* key)
245 const s_xbt_dictelm* current = xbt_dict_get_elm_or_null(dict, key);
247 if (current == nullptr)
250 return current->content;
254 * @brief Retrieve element from the dict (null-terminated key)
256 * @param dict the dealer of data
257 * @param key the key to find data
258 * @return the s_xbt_dictelm_t that we are looking for
260 * Search the given @a key. Returns nullptr when not found.
262 xbt_dictelm_t xbt_dict_get_elm_or_null(const_xbt_dict_t dict, const char* key)
264 unsigned int hash_code = xbt_str_hash(key);
265 xbt_dictelm_t current = dict->table[hash_code & dict->table_size];
267 while (current != nullptr && (hash_code != current->hash_code || strcmp(key, current->key)))
268 current = current->next;
273 * @brief Remove data from the dict (arbitrary key)
275 * @param dict the trash can
276 * @param key the key of the data to be removed
277 * @param key_len the size of the @a key
279 * Remove the entry associated with the given @a key (throws std::out_of_range)
281 void xbt_dict_remove_ext(xbt_dict_t dict, const char *key, int key_len)
283 unsigned int hash_code = xbt_str_hash_ext(key, key_len);
284 xbt_dictelm_t previous = nullptr;
285 xbt_dictelm_t current = dict->table[hash_code & dict->table_size];
287 while (current != nullptr && (hash_code != current->hash_code || key_len != current->key_len
288 || strncmp(key, current->key, key_len))) {
289 previous = current; /* save the previous node */
290 current = current->next;
293 if (current == nullptr)
294 throw std::out_of_range(simgrid::xbt::string_printf("key %.*s not found", key_len, key));
296 if (previous != nullptr) {
297 previous->next = current->next;
299 dict->table[hash_code & dict->table_size] = current->next;
303 if (not dict->table[hash_code & dict->table_size])
306 xbt_dictelm_free(dict, current);
311 * @brief Return the number of elements in the dict.
312 * @param dict a dictionary
314 int xbt_dict_length(const_xbt_dict_t dict)
320 * @brief test if the dict is empty or not
322 int xbt_dict_is_empty(const_xbt_dict_t dict)
324 return not dict || (xbt_dict_length(dict) == 0);