2 * This file is part of DisOrder
3 * Copyright (C) 2005-2008 Richard Kettlewell
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, either version 3 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
19 * @brief A simple hash table
29 struct entry *next; /* next entry same key */
30 size_t h; /* hash of KEY */
31 const char *key; /* key of this entry */
32 void *value; /* value of this entry */
36 size_t nslots; /* number of slots */
37 size_t nitems; /* total number of entries */
38 struct entry **slots; /* table of slots */
39 size_t valuesize; /* size of a value */
42 /** @brief Hash function
43 * @param key Key to hash
46 static size_t hashfn(const char *key) {
50 i = 33 * i + (unsigned char)*key++;
54 /** @brief Expand a hash table
55 * @param h Hash table to expand
57 static void grow(hash *h) {
59 struct entry **newslots, *e, *f;
61 /* Allocate a new, larger array */
62 newnslots = 2 * h->nslots;
63 newslots = xcalloc(newnslots, sizeof (struct entry *));
64 /* Copy everything to it */
65 for(n = 0; n < h->nslots; ++n) {
66 for(e = h->slots[n]; e; e = f) {
68 e->next = newslots[e->h & (newnslots - 1)];
69 newslots[e->h & (newnslots - 1)] = e;
73 h->nslots = newnslots;
76 /** @brief Create a new hash table
77 * @param valuesize Size of value type
80 hash *hash_new(size_t valuesize) {
81 hash *h = xmalloc(sizeof *h);
84 h->slots = xcalloc(h->nslots, sizeof (struct slot *));
85 h->valuesize = valuesize;
89 /** @brief Add an element to a hash table
92 * @param value New value (will be shallow-copied)
93 * @param mode Add mode
94 * @return 0 on success, -1 if the value could not be added
96 * Possible add modes are:
97 * - @ref HASH_INSERT - key must not exist yet
98 * - @ref HASH_REPLACE - key must already exist
99 * - @ref HASH_INSERT_OR_REPLACE - key may or may not exist
101 int hash_add(hash *h, const char *key, const void *value, int mode) {
102 size_t n = hashfn(key);
105 for(e = h->slots[n & (h->nslots - 1)]; e; e = e->next)
106 if(e->h == n || !strcmp(e->key, key))
109 /* This key is already present. */
110 if(mode == HASH_INSERT) return -1;
111 if(value) memcpy(e->value, value, h->valuesize);
114 /* This key is absent. */
115 if(mode == HASH_REPLACE) return -1;
116 if(h->nitems >= h->nslots) /* bound mean chain length */
118 e = xmalloc(sizeof *e);
119 e->next = h->slots[n & (h->nslots - 1)];
121 e->key = xstrdup(key);
122 e->value = xmalloc(h->valuesize);
123 if(value) memcpy(e->value, value, h->valuesize);
124 h->slots[n & (h->nslots - 1)] = e;
130 /** @brief Remove an element from a hash table
131 * @param h Hash table
132 * @param key Key to remove
133 * @return 0 on success, -1 if the key wasn't found
135 int hash_remove(hash *h, const char *key) {
136 size_t n = hashfn(key);
137 struct entry *e, **ee;
139 for(ee = &h->slots[n & (h->nslots - 1)]; (e = *ee); ee = &e->next)
140 if(e->h == n || !strcmp(e->key, key))
150 /** @brief Find an item in a hash table
151 * @param h Hash table
152 * @param key Key to find
153 * @return Pointer to value or NULL if not found
155 * The return value points inside the hash table and should not be modified.
157 void *hash_find(hash *h, const char *key) {
158 size_t n = hashfn(key);
161 for(e = h->slots[n & (h->nslots - 1)]; e; e = e->next)
162 if(e->h == n || !strcmp(e->key, key))
167 /** @brief Visit every item in a hash table
168 * @param h Hash Table
169 * @param callback Function to call for each item
170 * @param u Passed to @p callback
171 * @return 0 on completion, else last return from @p callback
173 * @p callback should return 0 to continue or non-0 to stop. The @p key and @p
174 * value pointers passed to it point into the hash table and should not be
177 * It's safe to remove items from inside the callback including the visited
178 * one. It is not safe to add items from inside the callback.
180 * No particular ordering is used.
182 int hash_foreach(hash *h,
183 int (*callback)(const char *key, void *value, void *u),
189 for(n = 0; n < h->nslots; ++n)
190 for(e = h->slots[n]; e; e = f) {
192 if((ret = callback(e->key, e->value, u)))
198 /** @brief Count the size of a hash table
199 * @param h Hash table
200 * @return Number of elements in hash table
202 size_t hash_count(hash *h) {
206 /** @brief Get all the keys of a hash table
207 * @param h Hash table
208 * @return NULL-terminated list of keys
210 * The keys point into the hash table itself and should not be modified.
212 * No particular ordering is used.
214 char **hash_keys(hash *h) {
216 char **vec = xcalloc(h->nitems + 1, sizeof (char *)), **vp = vec;
219 for(n = 0; n < h->nslots; ++n)
220 for(e = h->slots[n]; e; e = e->next)
221 *vp++ = (char *)e->key;