| 1 | /* |
| 2 | * Copyright (c) 2009-2016 Petri Lehtinen <petri@digip.org> |
| 3 | * |
| 4 | * This library is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the MIT license. See LICENSE for details. |
| 6 | */ |
| 7 | |
| 8 | #if HAVE_CONFIG_H |
| 9 | #include <jansson_private_config.h> |
| 10 | #endif |
| 11 | |
| 12 | #include <stdlib.h> |
| 13 | #include <string.h> |
| 14 | |
| 15 | #if HAVE_STDINT_H |
| 16 | #include <stdint.h> |
| 17 | #endif |
| 18 | |
| 19 | #include <jansson_config.h> /* for JSON_INLINE */ |
| 20 | #include "jansson_private.h" /* for container_of() */ |
| 21 | #include "hashtable.h" |
| 22 | |
| 23 | #ifndef INITIAL_HASHTABLE_ORDER |
| 24 | #define INITIAL_HASHTABLE_ORDER 3 |
| 25 | #endif |
| 26 | |
| 27 | typedef struct hashtable_list list_t; |
| 28 | typedef struct hashtable_pair pair_t; |
| 29 | typedef struct hashtable_bucket bucket_t; |
| 30 | |
| 31 | extern volatile uint32_t hashtable_seed; |
| 32 | |
| 33 | /* Implementation of the hash function */ |
| 34 | #include "lookup3.h" |
| 35 | |
| 36 | #define list_to_pair(list_) container_of(list_, pair_t, list) |
| 37 | #define ordered_list_to_pair(list_) container_of(list_, pair_t, ordered_list) |
| 38 | #define hash_str(key) ((size_t)hashlittle((key), strlen(key), hashtable_seed)) |
| 39 | |
| 40 | static JSON_INLINE void list_init(list_t *list) |
| 41 | { |
| 42 | list->next = list; |
| 43 | list->prev = list; |
| 44 | } |
| 45 | |
| 46 | static JSON_INLINE void list_insert(list_t *list, list_t *node) |
| 47 | { |
| 48 | node->next = list; |
| 49 | node->prev = list->prev; |
| 50 | list->prev->next = node; |
| 51 | list->prev = node; |
| 52 | } |
| 53 | |
| 54 | static JSON_INLINE void list_remove(list_t *list) |
| 55 | { |
| 56 | list->prev->next = list->next; |
| 57 | list->next->prev = list->prev; |
| 58 | } |
| 59 | |
| 60 | static JSON_INLINE int bucket_is_empty(hashtable_t *hashtable, bucket_t *bucket) |
| 61 | { |
| 62 | return bucket->first == &hashtable->list && bucket->first == bucket->last; |
| 63 | } |
| 64 | |
| 65 | static void insert_to_bucket(hashtable_t *hashtable, bucket_t *bucket, |
| 66 | list_t *list) |
| 67 | { |
| 68 | if(bucket_is_empty(hashtable, bucket)) |
| 69 | { |
| 70 | list_insert(&hashtable->list, list); |
| 71 | bucket->first = bucket->last = list; |
| 72 | } |
| 73 | else |
| 74 | { |
| 75 | list_insert(bucket->first, list); |
| 76 | bucket->first = list; |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | static pair_t *hashtable_find_pair(hashtable_t *hashtable, bucket_t *bucket, |
| 81 | const char *key, size_t hash) |
| 82 | { |
| 83 | list_t *list; |
| 84 | pair_t *pair; |
| 85 | |
| 86 | if(bucket_is_empty(hashtable, bucket)) |
| 87 | return NULL; |
| 88 | |
| 89 | list = bucket->first; |
| 90 | while(1) |
| 91 | { |
| 92 | pair = list_to_pair(list); |
| 93 | if(pair->hash == hash && strcmp(pair->key, key) == 0) |
| 94 | return pair; |
| 95 | |
| 96 | if(list == bucket->last) |
| 97 | break; |
| 98 | |
| 99 | list = list->next; |
| 100 | } |
| 101 | |
| 102 | return NULL; |
| 103 | } |
| 104 | |
| 105 | /* returns 0 on success, -1 if key was not found */ |
| 106 | static int hashtable_do_del(hashtable_t *hashtable, |
| 107 | const char *key, size_t hash) |
| 108 | { |
| 109 | pair_t *pair; |
| 110 | bucket_t *bucket; |
| 111 | size_t index; |
| 112 | |
| 113 | index = hash & hashmask(hashtable->order); |
| 114 | bucket = &hashtable->buckets[index]; |
| 115 | |
| 116 | pair = hashtable_find_pair(hashtable, bucket, key, hash); |
| 117 | if(!pair) |
| 118 | return -1; |
| 119 | |
| 120 | if(&pair->list == bucket->first && &pair->list == bucket->last) |
| 121 | bucket->first = bucket->last = &hashtable->list; |
| 122 | |
| 123 | else if(&pair->list == bucket->first) |
| 124 | bucket->first = pair->list.next; |
| 125 | |
| 126 | else if(&pair->list == bucket->last) |
| 127 | bucket->last = pair->list.prev; |
| 128 | |
| 129 | list_remove(&pair->list); |
| 130 | list_remove(&pair->ordered_list); |
| 131 | json_decref(pair->value); |
| 132 | |
| 133 | jsonp_free(pair); |
| 134 | hashtable->size--; |
| 135 | |
| 136 | return 0; |
| 137 | } |
| 138 | |
| 139 | static void hashtable_do_clear(hashtable_t *hashtable) |
| 140 | { |
| 141 | list_t *list, *next; |
| 142 | pair_t *pair; |
| 143 | |
| 144 | for(list = hashtable->list.next; list != &hashtable->list; list = next) |
| 145 | { |
| 146 | next = list->next; |
| 147 | pair = list_to_pair(list); |
| 148 | json_decref(pair->value); |
| 149 | jsonp_free(pair); |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | static int hashtable_do_rehash(hashtable_t *hashtable) |
| 154 | { |
| 155 | list_t *list, *next; |
| 156 | pair_t *pair; |
| 157 | size_t i, index, new_size, new_order; |
| 158 | struct hashtable_bucket *new_buckets; |
| 159 | |
| 160 | new_order = hashtable->order + 1; |
| 161 | new_size = hashsize(new_order); |
| 162 | |
| 163 | new_buckets = jsonp_malloc(new_size * sizeof(bucket_t)); |
| 164 | if(!new_buckets) |
| 165 | return -1; |
| 166 | |
| 167 | jsonp_free(hashtable->buckets); |
| 168 | hashtable->buckets = new_buckets; |
| 169 | hashtable->order = new_order; |
| 170 | |
| 171 | for(i = 0; i < hashsize(hashtable->order); i++) |
| 172 | { |
| 173 | hashtable->buckets[i].first = hashtable->buckets[i].last = |
| 174 | &hashtable->list; |
| 175 | } |
| 176 | |
| 177 | list = hashtable->list.next; |
| 178 | list_init(&hashtable->list); |
| 179 | |
| 180 | for(; list != &hashtable->list; list = next) { |
| 181 | next = list->next; |
| 182 | pair = list_to_pair(list); |
| 183 | index = pair->hash % new_size; |
| 184 | insert_to_bucket(hashtable, &hashtable->buckets[index], &pair->list); |
| 185 | } |
| 186 | |
| 187 | return 0; |
| 188 | } |
| 189 | |
| 190 | |
| 191 | int hashtable_init(hashtable_t *hashtable) |
| 192 | { |
| 193 | size_t i; |
| 194 | |
| 195 | hashtable->size = 0; |
| 196 | hashtable->order = INITIAL_HASHTABLE_ORDER; |
| 197 | hashtable->buckets = jsonp_malloc(hashsize(hashtable->order) * sizeof(bucket_t)); |
| 198 | if(!hashtable->buckets) |
| 199 | return -1; |
| 200 | |
| 201 | list_init(&hashtable->list); |
| 202 | list_init(&hashtable->ordered_list); |
| 203 | |
| 204 | for(i = 0; i < hashsize(hashtable->order); i++) |
| 205 | { |
| 206 | hashtable->buckets[i].first = hashtable->buckets[i].last = |
| 207 | &hashtable->list; |
| 208 | } |
| 209 | |
| 210 | return 0; |
| 211 | } |
| 212 | |
| 213 | void hashtable_close(hashtable_t *hashtable) |
| 214 | { |
| 215 | hashtable_do_clear(hashtable); |
| 216 | jsonp_free(hashtable->buckets); |
| 217 | } |
| 218 | |
| 219 | int hashtable_set(hashtable_t *hashtable, const char *key, json_t *value) |
| 220 | { |
| 221 | pair_t *pair; |
| 222 | bucket_t *bucket; |
| 223 | size_t hash, index; |
| 224 | |
| 225 | /* rehash if the load ratio exceeds 1 */ |
| 226 | if(hashtable->size >= hashsize(hashtable->order)) |
| 227 | if(hashtable_do_rehash(hashtable)) |
| 228 | return -1; |
| 229 | |
| 230 | hash = hash_str(key); |
| 231 | index = hash & hashmask(hashtable->order); |
| 232 | bucket = &hashtable->buckets[index]; |
| 233 | pair = hashtable_find_pair(hashtable, bucket, key, hash); |
| 234 | |
| 235 | if(pair) |
| 236 | { |
| 237 | json_decref(pair->value); |
| 238 | pair->value = value; |
| 239 | } |
| 240 | else |
| 241 | { |
| 242 | /* offsetof(...) returns the size of pair_t without the last, |
| 243 | flexible member. This way, the correct amount is |
| 244 | allocated. */ |
| 245 | |
| 246 | size_t len = strlen(key); |
| 247 | if(len >= (size_t)-1 - offsetof(pair_t, key)) { |
| 248 | /* Avoid an overflow if the key is very long */ |
| 249 | return -1; |
| 250 | } |
| 251 | |
| 252 | pair = jsonp_malloc(offsetof(pair_t, key) + len + 1); |
| 253 | if(!pair) |
| 254 | return -1; |
| 255 | |
| 256 | pair->hash = hash; |
| 257 | strncpy(pair->key, key, len + 1); |
| 258 | pair->value = value; |
| 259 | list_init(&pair->list); |
| 260 | list_init(&pair->ordered_list); |
| 261 | |
| 262 | insert_to_bucket(hashtable, bucket, &pair->list); |
| 263 | list_insert(&hashtable->ordered_list, &pair->ordered_list); |
| 264 | |
| 265 | hashtable->size++; |
| 266 | } |
| 267 | return 0; |
| 268 | } |
| 269 | |
| 270 | void *hashtable_get(hashtable_t *hashtable, const char *key) |
| 271 | { |
| 272 | pair_t *pair; |
| 273 | size_t hash; |
| 274 | bucket_t *bucket; |
| 275 | |
| 276 | hash = hash_str(key); |
| 277 | bucket = &hashtable->buckets[hash & hashmask(hashtable->order)]; |
| 278 | |
| 279 | pair = hashtable_find_pair(hashtable, bucket, key, hash); |
| 280 | if(!pair) |
| 281 | return NULL; |
| 282 | |
| 283 | return pair->value; |
| 284 | } |
| 285 | |
| 286 | int hashtable_del(hashtable_t *hashtable, const char *key) |
| 287 | { |
| 288 | size_t hash = hash_str(key); |
| 289 | return hashtable_do_del(hashtable, key, hash); |
| 290 | } |
| 291 | |
| 292 | void hashtable_clear(hashtable_t *hashtable) |
| 293 | { |
| 294 | size_t i; |
| 295 | |
| 296 | hashtable_do_clear(hashtable); |
| 297 | |
| 298 | for(i = 0; i < hashsize(hashtable->order); i++) |
| 299 | { |
| 300 | hashtable->buckets[i].first = hashtable->buckets[i].last = |
| 301 | &hashtable->list; |
| 302 | } |
| 303 | |
| 304 | list_init(&hashtable->list); |
| 305 | list_init(&hashtable->ordered_list); |
| 306 | hashtable->size = 0; |
| 307 | } |
| 308 | |
| 309 | void *hashtable_iter(hashtable_t *hashtable) |
| 310 | { |
| 311 | return hashtable_iter_next(hashtable, &hashtable->ordered_list); |
| 312 | } |
| 313 | |
| 314 | void *hashtable_iter_at(hashtable_t *hashtable, const char *key) |
| 315 | { |
| 316 | pair_t *pair; |
| 317 | size_t hash; |
| 318 | bucket_t *bucket; |
| 319 | |
| 320 | hash = hash_str(key); |
| 321 | bucket = &hashtable->buckets[hash & hashmask(hashtable->order)]; |
| 322 | |
| 323 | pair = hashtable_find_pair(hashtable, bucket, key, hash); |
| 324 | if(!pair) |
| 325 | return NULL; |
| 326 | |
| 327 | return &pair->ordered_list; |
| 328 | } |
| 329 | |
| 330 | void *hashtable_iter_next(hashtable_t *hashtable, void *iter) |
| 331 | { |
| 332 | list_t *list = (list_t *)iter; |
| 333 | if(list->next == &hashtable->ordered_list) |
| 334 | return NULL; |
| 335 | return list->next; |
| 336 | } |
| 337 | |
| 338 | void *hashtable_iter_key(void *iter) |
| 339 | { |
| 340 | pair_t *pair = ordered_list_to_pair((list_t *)iter); |
| 341 | return pair->key; |
| 342 | } |
| 343 | |
| 344 | void *hashtable_iter_value(void *iter) |
| 345 | { |
| 346 | pair_t *pair = ordered_list_to_pair((list_t *)iter); |
| 347 | return pair->value; |
| 348 | } |
| 349 | |
| 350 | void hashtable_iter_set(void *iter, json_t *value) |
| 351 | { |
| 352 | pair_t *pair = ordered_list_to_pair((list_t *)iter); |
| 353 | |
| 354 | json_decref(pair->value); |
| 355 | pair->value = value; |
| 356 | } |