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 if (dict_elm_mallocator == nullptr) {
37 static std::mutex init_mutex;
39 if (dict_elm_mallocator == nullptr) { // Just in case someone initialized it in between
41 xbt_mallocator_new(256, dict_elm_mallocator_new_f, dict_elm_mallocator_free_f, dict_elm_mallocator_reset_f);
42 atexit(xbt_dict_postexit);
50 * @param free_ctn function to call with (@a data as argument) when @a data is removed from the dictionary
51 * @return pointer to the destination
52 * @see xbt_dict_free()
54 * Creates and initialize a new dictionary with a default hashtable size.
55 * The dictionary is homogeneous: each element share the same free function.
57 xbt_dict_t xbt_dict_new_homogeneous(void_f_pvoid_t free_ctn)
59 xbt_dict_preinit(); // Make sure that the module is intialized
63 dict = xbt_new(s_xbt_dict_t, 1);
64 dict->free_f = free_ctn;
65 dict->table_size = 127;
66 dict->table = xbt_new0(xbt_dictelm_t, dict->table_size + 1);
75 * @param dict the dictionary to be freed
77 * Frees a dictionary with all the data
79 void xbt_dict_free(xbt_dict_t * dict)
81 if (dict != nullptr && *dict != nullptr) {
82 int table_size = (*dict)->table_size;
83 xbt_dictelm_t* table = (*dict)->table;
84 /* Warning: the size of the table is 'table_size+1'...
85 * This is because table_size is used as a binary mask in xbt_dict_rehash */
86 for (int i = 0; (*dict)->count && i <= table_size; i++) {
87 xbt_dictelm_t current = table[i];
88 xbt_dictelm_t previous;
90 while (current != nullptr) {
92 current = current->next;
93 xbt_dictelm_free(*dict, previous);
103 /** Returns the amount of elements in the dict */
104 unsigned int xbt_dict_size(const_xbt_dict_t dict)
106 return (dict != nullptr ? static_cast<unsigned int>(dict->count) : static_cast<unsigned int>(0));
109 /* Expend the size of the dict */
110 static void xbt_dict_rehash(xbt_dict_t dict)
112 const unsigned oldsize = dict->table_size + 1;
113 unsigned newsize = oldsize * 2;
115 auto* newtable = static_cast<xbt_dictelm_t*>(xbt_realloc(dict->table, newsize * sizeof(xbt_dictelm_t)));
116 std::fill(newtable + oldsize, newtable + newsize, nullptr); /* zero second half */
118 dict->table_size = newsize;
119 dict->table = newtable;
120 XBT_DEBUG("REHASH (%u->%u)", oldsize, newsize);
122 for (unsigned i = 0; i < oldsize; i++) {
123 xbt_dictelm_t* currcell = &newtable[i];
124 if (*currcell == nullptr) /* empty cell */
127 xbt_dictelm_t *twincell = currcell + oldsize;
128 xbt_dictelm_t *pprev = currcell;
129 xbt_dictelm_t bucklet = *currcell;
130 while (bucklet != nullptr) {
131 /* Since we use "& size" instead of "%size" and since the size was doubled, each bucklet of this cell must either:
132 - stay in cell i (ie, currcell)
133 - go to the cell i+oldsize (ie, twincell) */
134 if ((bucklet->hash_code & newsize) != i) { /* Move to b */
135 *pprev = bucklet->next;
136 bucklet->next = *twincell;
137 if (*twincell == nullptr)
141 pprev = &bucklet->next;
146 if (*currcell == nullptr) /* everything moved */
152 * @brief Add data to the dict (arbitrary key)
153 * @param dict the container
154 * @param key the key to set the new data
155 * @param key_len the size of the @a key
156 * @param data the data to add in the dict
158 * 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
161 void xbt_dict_set_ext(xbt_dict_t dict, const char* key, int key_len, void* data)
163 unsigned int hash_code = xbt_str_hash_ext(key, key_len);
165 xbt_dictelm_t current;
166 xbt_dictelm_t previous = nullptr;
168 XBT_CDEBUG(xbt_dict, "ADD %.*s hash = %u, size = %d, & = %u", key_len, key, hash_code,
169 dict->table_size, hash_code & dict->table_size);
170 current = dict->table[hash_code & dict->table_size];
171 while (current != nullptr && (hash_code != current->hash_code || key_len != current->key_len
172 || memcmp(key, current->key, key_len))) {
174 current = current->next;
177 if (current == nullptr) {
178 /* this key doesn't exist yet */
179 current = xbt_dictelm_new(key, key_len, hash_code, data);
181 if (previous == nullptr) {
182 dict->table[hash_code & dict->table_size] = current;
184 if ((dict->fill * 100) / (dict->table_size + 1) > MAX_FILL_PERCENT)
185 xbt_dict_rehash(dict);
187 previous->next = current;
190 XBT_CDEBUG(xbt_dict, "Replace %.*s by %.*s under key %.*s",
191 key_len, (char *) current->content, key_len, (char *) data, key_len, (char *) key);
192 /* there is already an element with the same key: overwrite it */
193 xbt_dictelm_set_data(dict, current, data);
198 * @brief Add data to the dict (null-terminated key)
200 * @param dict the dict
201 * @param key the key to set the new data
202 * @param data the data to add in the dict
204 * set the @a data in the structure under the @a key, which is a null terminated string.
206 void xbt_dict_set(xbt_dict_t dict, const char* key, void* data)
208 xbt_dict_set_ext(dict, key, strlen(key), data);
212 * @brief Retrieve data from the dict (arbitrary key)
214 * @param dict the dealer of data
215 * @param key the key to find data
216 * @param key_len the size of the @a key
217 * @return the data that we are looking for
219 * Search the given @a key. Returns nullptr when not found.
221 void* xbt_dict_get_or_null_ext(const_xbt_dict_t dict, const char* key, int key_len)
223 unsigned int hash_code = xbt_str_hash_ext(key, key_len);
224 const s_xbt_dictelm* current = dict->table[hash_code & dict->table_size];
226 while (current != nullptr && (hash_code != current->hash_code || key_len != current->key_len
227 || memcmp(key, current->key, key_len))) {
228 current = current->next;
231 if (current == nullptr)
234 return current->content;
238 * @brief Retrieve data from the dict (null-terminated key)
240 * @param dict the dealer of data
241 * @param key the key to find data
242 * @return the data that we are looking for
244 * Search the given @a key. Returns nullptr when not found.
246 void* xbt_dict_get_or_null(const_xbt_dict_t dict, const char* key)
248 const s_xbt_dictelm* current = xbt_dict_get_elm_or_null(dict, key);
250 if (current == nullptr)
253 return current->content;
257 * @brief Retrieve element from the dict (null-terminated key)
259 * @param dict the dealer of data
260 * @param key the key to find data
261 * @return the s_xbt_dictelm_t that we are looking for
263 * Search the given @a key. Returns nullptr when not found.
265 xbt_dictelm_t xbt_dict_get_elm_or_null(const_xbt_dict_t dict, const char* key)
267 unsigned int hash_code = xbt_str_hash(key);
268 xbt_dictelm_t current = dict->table[hash_code & dict->table_size];
270 while (current != nullptr && (hash_code != current->hash_code || strcmp(key, current->key)))
271 current = current->next;
276 * @brief Remove data from the dict (arbitrary key)
278 * @param dict the trash can
279 * @param key the key of the data to be removed
280 * @param key_len the size of the @a key
282 * Remove the entry associated with the given @a key (throws std::out_of_range)
284 void xbt_dict_remove_ext(xbt_dict_t dict, const char *key, int key_len)
286 unsigned int hash_code = xbt_str_hash_ext(key, key_len);
287 xbt_dictelm_t previous = nullptr;
288 xbt_dictelm_t current = dict->table[hash_code & dict->table_size];
290 while (current != nullptr && (hash_code != current->hash_code || key_len != current->key_len
291 || strncmp(key, current->key, key_len))) {
292 previous = current; /* save the previous node */
293 current = current->next;
296 if (current == nullptr)
297 throw std::out_of_range(simgrid::xbt::string_printf("key %.*s not found", key_len, key));
299 if (previous != nullptr) {
300 previous->next = current->next;
302 dict->table[hash_code & dict->table_size] = current->next;
306 if (not dict->table[hash_code & dict->table_size])
309 xbt_dictelm_free(dict, current);
314 * @brief Return the number of elements in the dict.
315 * @param dict a dictionary
317 int xbt_dict_length(const_xbt_dict_t dict)
323 * @brief test if the dict is empty or not
325 int xbt_dict_is_empty(const_xbt_dict_t dict)
327 return not dict || (xbt_dict_length(dict) == 0);