src/pulsecore/hashmap.c

   1 /***
   2   This file is part of PulseAudio.
   3
   4   Copyright 2004-2008 Lennart Poettering
   5
   6   PulseAudio is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU Lesser General Public License as published
   8   by the Free Software Foundation; either version 2.1 of the License,
   9   or (at your option) any later version.
  10
  11   PulseAudio is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with PulseAudio; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <stdlib.h>
  27
  28 #include <pulse/xmalloc.h>
  29 #include <pulsecore/idxset.h>
  30 #include <pulsecore/flist.h>
  31 #include <pulsecore/macro.h>
  32
  33 #include "hashmap.h"
  34
  35 #define NBUCKETS 127
  36
  37 struct hashmap_entry {
  38     const void *key;
  39     void *value;
  40
  41     struct hashmap_entry *bucket_next, *bucket_previous;
  42     struct hashmap_entry *iterate_next, *iterate_previous;
  43 };
  44
  45 struct pa_hashmap {
  46     pa_hash_func_t hash_func;
  47     pa_compare_func_t compare_func;
  48
  49     struct hashmap_entry *iterate_list_head, *iterate_list_tail;
  50     unsigned n_entries;
  51 };
  52
  53 #define BY_HASH(h) ((struct hashmap_entry**) ((uint8_t*) (h) + PA_ALIGN(sizeof(pa_hashmap))))
  54
  55 PA_STATIC_FLIST_DECLARE(entries, 0, pa_xfree);
  56
  57 pa_hashmap *pa_hashmap_new(pa_hash_func_t hash_func, pa_compare_func_t compare_func) {
  58     pa_hashmap *h;
  59
  60     h = pa_xmalloc0(PA_ALIGN(sizeof(pa_hashmap)) + NBUCKETS*sizeof(struct hashmap_entry*));
  61
  62     h->hash_func = hash_func ? hash_func : pa_idxset_trivial_hash_func;
  63     h->compare_func = compare_func ? compare_func : pa_idxset_trivial_compare_func;
  64
  65     h->n_entries = 0;
  66     h->iterate_list_head = h->iterate_list_tail = NULL;
  67
  68     return h;
  69 }
  70
  71 static void remove_entry(pa_hashmap *h, struct hashmap_entry *e) {
  72     pa_assert(h);
  73     pa_assert(e);
  74
  75     /* Remove from iteration list */
  76     if (e->iterate_next)
  77         e->iterate_next->iterate_previous = e->iterate_previous;
  78     else
  79         h->iterate_list_tail = e->iterate_previous;
  80
  81     if (e->iterate_previous)
  82         e->iterate_previous->iterate_next = e->iterate_next;
  83     else
  84         h->iterate_list_head = e->iterate_next;
  85
  86     /* Remove from hash table bucket list */
  87     if (e->bucket_next)
  88         e->bucket_next->bucket_previous = e->bucket_previous;
  89
  90     if (e->bucket_previous)
  91         e->bucket_previous->bucket_next = e->bucket_next;
  92     else {
  93         unsigned hash = h->hash_func(e->key) % NBUCKETS;
  94         BY_HASH(h)[hash] = e->bucket_next;
  95     }
  96
  97     if (pa_flist_push(PA_STATIC_FLIST_GET(entries), e) < 0)
  98         pa_xfree(e);
  99
 100     pa_assert(h->n_entries >= 1);
 101     h->n_entries--;
 102 }
 103
 104 void pa_hashmap_free(pa_hashmap*h, pa_free2_cb_t free_cb, void *userdata) {
 105     pa_assert(h);
 106
 107     while (h->iterate_list_head) {
 108         void *data;
 109         data = h->iterate_list_head->value;
 110         remove_entry(h, h->iterate_list_head);
 111
 112         if (free_cb)
 113             free_cb(data, userdata);
 114     }
 115
 116     pa_xfree(h);
 117 }
 118
 119 static struct hashmap_entry *hash_scan(pa_hashmap *h, unsigned hash, const void *key) {
 120     struct hashmap_entry *e;
 121     pa_assert(h);
 122     pa_assert(hash < NBUCKETS);
 123
 124     for (e = BY_HASH(h)[hash]; e; e = e->bucket_next)
 125         if (h->compare_func(e->key, key) == 0)
 126             return e;
 127
 128     return NULL;
 129 }
 130
 131 int pa_hashmap_put(pa_hashmap *h, const void *key, void *value) {
 132     struct hashmap_entry *e;
 133     unsigned hash;
 134
 135     pa_assert(h);
 136
 137     hash = h->hash_func(key) % NBUCKETS;
 138
 139     if (hash_scan(h, hash, key))
 140         return -1;
 141
 142     if (!(e = pa_flist_pop(PA_STATIC_FLIST_GET(entries))))
 143         e = pa_xnew(struct hashmap_entry, 1);
 144
 145     e->key = key;
 146     e->value = value;
 147
 148     /* Insert into hash table */
 149     e->bucket_next = BY_HASH(h)[hash];
 150     e->bucket_previous = NULL;
 151     if (BY_HASH(h)[hash])
 152         BY_HASH(h)[hash]->bucket_previous = e;
 153     BY_HASH(h)[hash] = e;
 154
 155     /* Insert into iteration list */
 156     e->iterate_previous = h->iterate_list_tail;
 157     e->iterate_next = NULL;
 158     if (h->iterate_list_tail) {
 159         pa_assert(h->iterate_list_head);
 160         h->iterate_list_tail->iterate_next = e;
 161     } else {
 162         pa_assert(!h->iterate_list_head);
 163         h->iterate_list_head = e;
 164     }
 165     h->iterate_list_tail = e;
 166
 167     h->n_entries++;
 168     pa_assert(h->n_entries >= 1);
 169
 170     return 0;
 171 }
 172
 173 void* pa_hashmap_get(pa_hashmap *h, const void *key) {
 174     unsigned hash;
 175     struct hashmap_entry *e;
 176
 177     pa_assert(h);
 178
 179     hash = h->hash_func(key) % NBUCKETS;
 180
 181     if (!(e = hash_scan(h, hash, key)))
 182         return NULL;
 183
 184     return e->value;
 185 }
 186
 187 void* pa_hashmap_remove(pa_hashmap *h, const void *key) {
 188     struct hashmap_entry *e;
 189     unsigned hash;
 190     void *data;
 191
 192     pa_assert(h);
 193
 194     hash = h->hash_func(key) % NBUCKETS;
 195
 196     if (!(e = hash_scan(h, hash, key)))
 197         return NULL;
 198
 199     data = e->value;
 200     remove_entry(h, e);
 201
 202     return data;
 203 }
 204
 205 void *pa_hashmap_iterate(pa_hashmap *h, void **state, const void **key) {
 206     struct hashmap_entry *e;
 207
 208     pa_assert(h);
 209     pa_assert(state);
 210
 211     if (*state == (void*) -1)
 212         goto at_end;
 213
 214     if (!*state && !h->iterate_list_head)
 215         goto at_end;
 216
 217     e = *state ? *state : h->iterate_list_head;
 218
 219     if (e->iterate_next)
 220         *state = e->iterate_next;
 221     else
 222         *state = (void*) -1;
 223
 224     if (key)
 225         *key = e->key;
 226
 227     return e->value;
 228
 229 at_end:
 230     *state = (void *) -1;
 231
 232     if (key)
 233         *key = NULL;
 234
 235     return NULL;
 236 }
 237
 238 void *pa_hashmap_iterate_backwards(pa_hashmap *h, void **state, const void **key) {
 239     struct hashmap_entry *e;
 240
 241     pa_assert(h);
 242     pa_assert(state);
 243
 244     if (*state == (void*) -1)
 245         goto at_beginning;
 246
 247     if (!*state && !h->iterate_list_tail)
 248         goto at_beginning;
 249
 250     e = *state ? *state : h->iterate_list_tail;
 251
 252     if (e->iterate_previous)
 253         *state = e->iterate_previous;
 254     else
 255         *state = (void*) -1;
 256
 257     if (key)
 258         *key = e->key;
 259
 260     return e->value;
 261
 262 at_beginning:
 263     *state = (void *) -1;
 264
 265     if (key)
 266         *key = NULL;
 267
 268     return NULL;
 269 }
 270
 271 void* pa_hashmap_first(pa_hashmap *h) {
 272     pa_assert(h);
 273
 274     if (!h->iterate_list_head)
 275         return NULL;
 276
 277     return h->iterate_list_head->value;
 278 }
 279
 280 void* pa_hashmap_last(pa_hashmap *h) {
 281     pa_assert(h);
 282
 283     if (!h->iterate_list_tail)
 284         return NULL;
 285
 286     return h->iterate_list_tail->value;
 287 }
 288
 289 void* pa_hashmap_steal_first(pa_hashmap *h) {
 290     void *data;
 291
 292     pa_assert(h);
 293
 294     if (!h->iterate_list_head)
 295         return NULL;
 296
 297     data = h->iterate_list_head->value;
 298     remove_entry(h, h->iterate_list_head);
 299
 300     return data;
 301 }
 302
 303 unsigned pa_hashmap_size(pa_hashmap *h) {
 304     pa_assert(h);
 305
 306     return h->n_entries;
 307 }
 308
 309 pa_bool_t pa_hashmap_isempty(pa_hashmap *h) {
 310     pa_assert(h);
 311
 312     return h->n_entries == 0;
 313 }