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"
21 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_dict, xbt, "Dictionaries provide the same functionalities as hash tables");
23 constexpr int MAX_FILL_PERCENT = 80;
25 /** Handle the dict mallocators init/fini cycle. */
26 static void xbt_dict_postexit()
28 if (dict_elm_mallocator != nullptr) {
29 xbt_mallocator_free(dict_elm_mallocator);
30 dict_elm_mallocator = nullptr;
33 static void xbt_dict_preinit()
35 if (dict_elm_mallocator == nullptr) {
37 xbt_mallocator_new(256, dict_elm_mallocator_new_f, dict_elm_mallocator_free_f, dict_elm_mallocator_reset_f);
38 atexit(xbt_dict_postexit);
44 * @param free_ctn function to call with (@a data as argument) when @a data is removed from the dictionary
45 * @return pointer to the destination
46 * @see xbt_dict_free()
48 * Creates and initialize a new dictionary with a default hashtable size.
49 * The dictionary is homogeneous: each element share the same free function.
51 xbt_dict_t xbt_dict_new_homogeneous(void_f_pvoid_t free_ctn)
53 xbt_dict_preinit(); // Make sure that the module is intialized
57 dict = xbt_new(s_xbt_dict_t, 1);
58 dict->free_f = free_ctn;
59 dict->table_size = 127;
60 dict->table = xbt_new0(xbt_dictelm_t, dict->table_size + 1);
69 * @param dict the dictionary to be freed
71 * Frees a dictionary with all the data
73 void xbt_dict_free(xbt_dict_t * dict)
75 if (dict != nullptr && *dict != nullptr) {
76 int table_size = (*dict)->table_size;
77 xbt_dictelm_t* table = (*dict)->table;
78 /* Warning: the size of the table is 'table_size+1'...
79 * This is because table_size is used as a binary mask in xbt_dict_rehash */
80 for (int i = 0; (*dict)->count && i <= table_size; i++) {
81 xbt_dictelm_t current = table[i];
82 xbt_dictelm_t previous;
84 while (current != nullptr) {
86 current = current->next;
87 xbt_dictelm_free(*dict, previous);
97 /** Returns the amount of elements in the dict */
98 unsigned int xbt_dict_size(const_xbt_dict_t dict)
100 return (dict != nullptr ? static_cast<unsigned int>(dict->count) : static_cast<unsigned int>(0));
103 /* Expend the size of the dict */
104 static void xbt_dict_rehash(xbt_dict_t dict)
106 const unsigned oldsize = dict->table_size + 1;
107 unsigned newsize = oldsize * 2;
109 auto* newtable = static_cast<xbt_dictelm_t*>(xbt_realloc(dict->table, newsize * sizeof(xbt_dictelm_t)));
110 std::fill(newtable + oldsize, newtable + newsize, nullptr); /* zero second half */
112 dict->table_size = newsize;
113 dict->table = newtable;
114 XBT_DEBUG("REHASH (%u->%u)", oldsize, newsize);
116 for (unsigned i = 0; i < oldsize; i++) {
117 xbt_dictelm_t* currcell = &newtable[i];
118 if (*currcell == nullptr) /* empty cell */
121 xbt_dictelm_t *twincell = currcell + oldsize;
122 xbt_dictelm_t *pprev = currcell;
123 xbt_dictelm_t bucklet = *currcell;
124 while (bucklet != nullptr) {
125 /* Since we use "& size" instead of "%size" and since the size was doubled, each bucklet of this cell must either:
126 - stay in cell i (ie, currcell)
127 - go to the cell i+oldsize (ie, twincell) */
128 if ((bucklet->hash_code & newsize) != i) { /* Move to b */
129 *pprev = bucklet->next;
130 bucklet->next = *twincell;
131 if (*twincell == nullptr)
135 pprev = &bucklet->next;
140 if (*currcell == nullptr) /* everything moved */
146 * @brief Add data to the dict (arbitrary key)
147 * @param dict the container
148 * @param key the key to set the new data
149 * @param key_len the size of the @a key
150 * @param data the data to add in the dict
152 * 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
155 void xbt_dict_set_ext(xbt_dict_t dict, const char* key, int key_len, void* data)
157 unsigned int hash_code = xbt_str_hash_ext(key, key_len);
159 xbt_dictelm_t current;
160 xbt_dictelm_t previous = nullptr;
162 XBT_CDEBUG(xbt_dict, "ADD %.*s hash = %u, size = %d, & = %u", key_len, key, hash_code,
163 dict->table_size, hash_code & dict->table_size);
164 current = dict->table[hash_code & dict->table_size];
165 while (current != nullptr && (hash_code != current->hash_code || key_len != current->key_len
166 || memcmp(key, current->key, key_len))) {
168 current = current->next;
171 if (current == nullptr) {
172 /* this key doesn't exist yet */
173 current = xbt_dictelm_new(key, key_len, hash_code, data);
175 if (previous == nullptr) {
176 dict->table[hash_code & dict->table_size] = current;
178 if ((dict->fill * 100) / (dict->table_size + 1) > MAX_FILL_PERCENT)
179 xbt_dict_rehash(dict);
181 previous->next = current;
184 XBT_CDEBUG(xbt_dict, "Replace %.*s by %.*s under key %.*s",
185 key_len, (char *) current->content, key_len, (char *) data, key_len, (char *) key);
186 /* there is already an element with the same key: overwrite it */
187 xbt_dictelm_set_data(dict, current, data);
192 * @brief Add data to the dict (null-terminated key)
194 * @param dict the dict
195 * @param key the key to set the new data
196 * @param data the data to add in the dict
198 * set the @a data in the structure under the @a key, which is a null terminated string.
200 void xbt_dict_set(xbt_dict_t dict, const char* key, void* data)
202 xbt_dict_set_ext(dict, key, strlen(key), data);
206 * @brief Retrieve data from the dict (arbitrary key)
208 * @param dict the dealer of data
209 * @param key the key to find data
210 * @param key_len the size of the @a key
211 * @return the data that we are looking for
213 * Search the given @a key. Returns nullptr when not found.
215 void* xbt_dict_get_or_null_ext(const_xbt_dict_t dict, const char* key, int key_len)
217 unsigned int hash_code = xbt_str_hash_ext(key, key_len);
218 const s_xbt_dictelm* current = dict->table[hash_code & dict->table_size];
220 while (current != nullptr && (hash_code != current->hash_code || key_len != current->key_len
221 || memcmp(key, current->key, key_len))) {
222 current = current->next;
225 if (current == nullptr)
228 return current->content;
232 * @brief Retrieve data from the dict (null-terminated key)
234 * @param dict the dealer of data
235 * @param key the key to find data
236 * @return the data that we are looking for
238 * Search the given @a key. Returns nullptr when not found.
240 void* xbt_dict_get_or_null(const_xbt_dict_t dict, const char* key)
242 const s_xbt_dictelm* current = xbt_dict_get_elm_or_null(dict, key);
244 if (current == nullptr)
247 return current->content;
251 * @brief Retrieve element from the dict (null-terminated key)
253 * @param dict the dealer of data
254 * @param key the key to find data
255 * @return the s_xbt_dictelm_t that we are looking for
257 * Search the given @a key. Returns nullptr when not found.
259 xbt_dictelm_t xbt_dict_get_elm_or_null(const_xbt_dict_t dict, const char* key)
261 unsigned int hash_code = xbt_str_hash(key);
262 xbt_dictelm_t current = dict->table[hash_code & dict->table_size];
264 while (current != nullptr && (hash_code != current->hash_code || strcmp(key, current->key)))
265 current = current->next;
270 * @brief Remove data from the dict (arbitrary key)
272 * @param dict the trash can
273 * @param key the key of the data to be removed
274 * @param key_len the size of the @a key
276 * Remove the entry associated with the given @a key (throws std::out_of_range)
278 void xbt_dict_remove_ext(xbt_dict_t dict, const char *key, int key_len)
280 unsigned int hash_code = xbt_str_hash_ext(key, key_len);
281 xbt_dictelm_t previous = nullptr;
282 xbt_dictelm_t current = dict->table[hash_code & dict->table_size];
284 while (current != nullptr && (hash_code != current->hash_code || key_len != current->key_len
285 || strncmp(key, current->key, key_len))) {
286 previous = current; /* save the previous node */
287 current = current->next;
290 if (current == nullptr)
291 throw std::out_of_range(simgrid::xbt::string_printf("key %.*s not found", key_len, key));
293 if (previous != nullptr) {
294 previous->next = current->next;
296 dict->table[hash_code & dict->table_size] = current->next;
300 if (not dict->table[hash_code & dict->table_size])
303 xbt_dictelm_free(dict, current);
308 * @brief Return the number of elements in the dict.
309 * @param dict a dictionary
311 int xbt_dict_length(const_xbt_dict_t dict)
317 * @brief test if the dict is empty or not
319 int xbt_dict_is_empty(const_xbt_dict_t dict)
321 return not dict || (xbt_dict_length(dict) == 0);