1 /* Map data type implemented by a hash table.
2 Copyright (C) 2006, 2008-2021 Free Software Foundation, Inc.
3 Written by Bruno Haible <bruno@clisp.org>, 2018.
4
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.
9
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.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17
18 #include <config.h>
19
20 /* Specification. */
21 #include "gl_hash_map.h"
22
23 #include <stdint.h> /* for uintptr_t, SIZE_MAX */
24 #include <stdlib.h>
25
26 #include "xsize.h"
27
28 /* --------------------------- gl_map_t Data Type --------------------------- */
29
30 #include "gl_anyhash1.h"
31
32 /* Concrete list node implementation, valid for this file only. */
33 struct gl_list_node_impl
34 {
35 struct gl_hash_entry h; /* hash table entry fields; must be first */
36 const void *key;
37 const void *value;
38 };
39 typedef struct gl_list_node_impl * gl_list_node_t;
40
41 /* Concrete gl_map_impl type, valid for this file only. */
42 struct gl_map_impl
43 {
44 struct gl_map_impl_base base;
45 gl_mapkey_hashcode_fn hashcode_fn;
46 /* A hash table: managed as an array of collision lists. */
47 struct gl_hash_entry **table;
48 size_t table_size;
49 /* Number of hash table entries. */
50 size_t count;
51 };
52
53 #define CONTAINER_T gl_map_t
54 #define CONTAINER_COUNT(map) (map)->count
55 #include "gl_anyhash2.h"
56
57 /* --------------------------- gl_map_t Data Type --------------------------- */
58
59 static gl_map_t
60 gl_hash_nx_create_empty (gl_map_implementation_t implementation,
61 gl_mapkey_equals_fn equals_fn,
62 gl_mapkey_hashcode_fn hashcode_fn,
63 gl_mapkey_dispose_fn kdispose_fn,
64 gl_mapvalue_dispose_fn vdispose_fn)
65 {
66 struct gl_map_impl *map =
67 (struct gl_map_impl *) malloc (sizeof (struct gl_map_impl));
68
69 if (map == NULL)
70 return NULL;
71
72 map->base.vtable = implementation;
73 map->base.equals_fn = equals_fn;
74 map->base.kdispose_fn = kdispose_fn;
75 map->base.vdispose_fn = vdispose_fn;
76 map->hashcode_fn = hashcode_fn;
77 map->table_size = 11;
78 map->table =
79 (gl_hash_entry_t *) calloc (map->table_size, sizeof (gl_hash_entry_t));
80 if (map->table == NULL)
81 goto fail;
82 map->count = 0;
83
84 return map;
85
86 fail:
87 free (map);
88 return NULL;
89 }
90
91 static size_t _GL_ATTRIBUTE_PURE
92 gl_hash_size (gl_map_t map)
93 {
94 return map->count;
95 }
96
97 static bool _GL_ATTRIBUTE_PURE
98 gl_hash_search (gl_map_t map, const void *key, const void **valuep)
99 {
100 size_t hashcode =
101 (map->hashcode_fn != NULL
102 ? map->hashcode_fn (key)
103 : (size_t)(uintptr_t) key);
104 size_t bucket = hashcode % map->table_size;
105 gl_mapkey_equals_fn equals = map->base.equals_fn;
106
107 /* Look for a match in the hash bucket. */
108 gl_list_node_t node;
109
110 for (node = (gl_list_node_t) map->table[bucket];
111 node != NULL;
112 node = (gl_list_node_t) node->h.hash_next)
113 if (node->h.hashcode == hashcode
114 && (equals != NULL
115 ? equals (key, node->key)
116 : key == node->key))
117 {
118 *valuep = node->value;
119 return true;
120 }
121 return false;
122 }
123
124 static int
125 gl_hash_nx_getput (gl_map_t map, const void *key, const void *value,
126 const void **oldvaluep)
127 {
128 size_t hashcode =
129 (map->hashcode_fn != NULL
130 ? map->hashcode_fn (key)
131 : (size_t)(uintptr_t) key);
132 size_t bucket = hashcode % map->table_size;
133 gl_mapkey_equals_fn equals = map->base.equals_fn;
134
135 /* Look for a match in the hash bucket. */
136 {
137 gl_list_node_t node;
138
139 for (node = (gl_list_node_t) map->table[bucket];
140 node != NULL;
141 node = (gl_list_node_t) node->h.hash_next)
142 if (node->h.hashcode == hashcode
143 && (equals != NULL
144 ? equals (key, node->key)
145 : key == node->key))
146 {
147 *oldvaluep = node->value;
148 node->value = value;
149 return 0;
150 }
151 }
152
153 /* Allocate a new node. */
154 gl_list_node_t node =
155 (struct gl_list_node_impl *) malloc (sizeof (struct gl_list_node_impl));
156
157 if (node == NULL)
158 return -1;
159
160 node->key = key;
161 node->value = value;
162 node->h.hashcode = hashcode;
163
164 /* Add node to the hash table. */
165 node->h.hash_next = map->table[bucket];
166 map->table[bucket] = &node->h;
167
168 /* Add node to the map. */
169 map->count++;
170
171 hash_resize_after_add (map);
172
173 return 1;
174 }
175
176 static bool
177 gl_hash_getremove (gl_map_t map, const void *key, const void **oldvaluep)
178 {
179 size_t hashcode =
180 (map->hashcode_fn != NULL
181 ? map->hashcode_fn (key)
182 : (size_t)(uintptr_t) key);
183 size_t bucket = hashcode % map->table_size;
184 gl_mapkey_equals_fn equals = map->base.equals_fn;
185
186 /* Look for the first match in the hash bucket. */
187 gl_list_node_t *nodep;
188
189 for (nodep = (gl_list_node_t *) &map->table[bucket];
190 *nodep != NULL;
191 nodep = (gl_list_node_t *) &(*nodep)->h.hash_next)
192 {
193 gl_list_node_t node = *nodep;
194 if (node->h.hashcode == hashcode
195 && (equals != NULL
196 ? equals (key, node->key)
197 : key == node->key))
198 {
199 *oldvaluep = node->value;
200
201 /* Remove node from the hash table. */
202 *nodep = (gl_list_node_t) node->h.hash_next;
203
204 /* Remove node from the map. */
205 map->count--;
206
207 if (map->base.kdispose_fn != NULL)
208 map->base.kdispose_fn (node->key);
209 free (node);
210 return true;
211 }
212 }
213
214 return false;
215 }
216
217 static void
218 gl_hash_free (gl_map_t map)
219 {
220 if (map->count > 0)
221 {
222 gl_mapkey_dispose_fn kdispose = map->base.kdispose_fn;
223 gl_mapvalue_dispose_fn vdispose = map->base.vdispose_fn;
224 struct gl_hash_entry **table = map->table;
225 size_t i;
226
227 for (i = map->table_size; i > 0; )
228 {
229 gl_hash_entry_t node = table[--i];
230
231 while (node != NULL)
232 {
233 gl_hash_entry_t next = node->hash_next;
234
235 /* Free the entry. */
236 if (vdispose != NULL)
237 vdispose (((gl_list_node_t) node)->value);
238 if (kdispose != NULL)
239 kdispose (((gl_list_node_t) node)->key);
240 free (node);
241
242 node = next;
243 }
244 }
245 }
246
247 free (map->table);
248 free (map);
249 }
250
251 /* ---------------------- gl_map_iterator_t Data Type ---------------------- */
252
253 /* Here we iterate through the hash buckets. Therefore the order in which the
254 pairs are returned is unpredictable. */
255
256 static gl_map_iterator_t
257 gl_hash_iterator (gl_map_t map)
258 {
259 gl_map_iterator_t result;
260
261 result.vtable = map->base.vtable;
262 result.map = map;
263 result.p = NULL; /* runs through the nodes of a bucket */
264 result.i = 0; /* index of the bucket that p points into + 1 */
265 result.j = map->table_size;
266 #if defined GCC_LINT || defined lint
267 result.q = NULL;
268 result.count = 0;
269 #endif
270
271 return result;
272 }
273
274 static bool
275 gl_hash_iterator_next (gl_map_iterator_t *iterator,
276 const void **keyp, const void **valuep)
277 {
278 if (iterator->p != NULL)
279 {
280 /* We're traversing a bucket. */
281 gl_list_node_t node = (gl_list_node_t) iterator->p;
282 *keyp = node->key;
283 *valuep = node->value;
284 iterator->p = (gl_list_node_t) node->h.hash_next;
285 return true;
286 }
287 else
288 {
289 /* Find the next bucket that is not empty. */
290 size_t j = iterator->j;
291 size_t i = iterator->i;
292
293 if (i < j)
294 {
295 gl_hash_entry_t *table = iterator->map->table;
296 do
297 {
298 gl_list_node_t node = (gl_list_node_t) table[i++];
299 if (node != NULL)
300 {
301 *keyp = node->key;
302 *valuep = node->value;
303 iterator->p = (gl_list_node_t) node->h.hash_next;
304 iterator->i = i;
305 return true;
306 }
307 }
308 while (i < j);
309 }
310 /* Here iterator->p is still NULL, and i == j. */
311 iterator->i = j;
312 return false;
313 }
314 }
315
316 static void
317 gl_hash_iterator_free (gl_map_iterator_t *iterator)
318 {
319 }
320
321
322 const struct gl_map_implementation gl_hash_map_implementation =
323 {
324 gl_hash_nx_create_empty,
325 gl_hash_size,
326 gl_hash_search,
327 gl_hash_nx_getput,
328 gl_hash_getremove,
329 gl_hash_free,
330 gl_hash_iterator,
331 gl_hash_iterator_next,
332 gl_hash_iterator_free
333 };