src/dict.h

   1 /* Hash Tables Implementation.
   2  *
   3  * This file implements in memory hash tables with insert/del/replace/find/
   4  * get-random-element operations. Hash tables will auto resize if needed
   5  * tables of power of two in size are used, collisions are handled by
   6  * chaining. See the source code for more information... :)
   7  *
   8  * Copyright (c) 2006-2010, Salvatore Sanfilippo <antirez at gmail dot com>
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions are met:
  13  *
  14  *   * Redistributions of source code must retain the above copyright notice,
  15  *     this list of conditions and the following disclaimer.
  16  *   * Redistributions in binary form must reproduce the above copyright
  17  *     notice, this list of conditions and the following disclaimer in the
  18  *     documentation and/or other materials provided with the distribution.
  19  *   * Neither the name of Redis nor the names of its contributors may be used
  20  *     to endorse or promote products derived from this software without
  21  *     specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  24  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  27  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  28  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  29  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  30  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  31  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  32  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  33  * POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 #include <stdint.h>
  37
  38 #ifndef __DICT_H
  39 #define __DICT_H
  40
  41 #define DICT_OK 0
  42 #define DICT_ERR 1
  43
  44 /* Unused arguments generate annoying warnings... */
  45 #define DICT_NOTUSED(V) ((void) V)
  46
  47 typedef struct dictEntry {
  48     void *key;
  49     union {
  50         void *val;
  51         uint64_t u64;
  52         int64_t i64;
  53     } v;
  54     struct dictEntry *next;
  55 } dictEntry;
  56
  57 typedef struct dictType {
  58     unsigned int (*hashFunction)(const void *key);
  59     void *(*keyDup)(void *privdata, const void *key);
  60     void *(*valDup)(void *privdata, const void *obj);
  61     int (*keyCompare)(void *privdata, const void *key1, const void *key2);
  62     void (*keyDestructor)(void *privdata, void *key);
  63     void (*valDestructor)(void *privdata, void *obj);
  64 } dictType;
  65
  66 /* This is our hash table structure. Every dictionary has two of this as we
  67  * implement incremental rehashing, for the old to the new table. */
  68 typedef struct dictht {
  69     dictEntry **table;
  70     unsigned long size;
  71     unsigned long sizemask;
  72     unsigned long used;
  73 } dictht;
  74
  75 typedef struct dict {
  76     dictType *type;
  77     void *privdata;
  78     dictht ht[2];
  79     int rehashidx; /* rehashing not in progress if rehashidx == -1 */
  80     int iterators; /* number of iterators currently running */
  81 } dict;
  82
  83 /* If safe is set to 1 this is a safe iteartor, that means, you can call
  84  * dictAdd, dictFind, and other functions against the dictionary even while
  85  * iterating. Otherwise it is a non safe iterator, and only dictNext()
  86  * should be called while iterating. */
  87 typedef struct dictIterator {
  88     dict *d;
  89     int table, index, safe;
  90     dictEntry *entry, *nextEntry;
  91 } dictIterator;
  92
  93 /* This is the initial size of every hash table */
  94 #define DICT_HT_INITIAL_SIZE     4
  95
  96 /* ------------------------------- Macros ------------------------------------*/
  97 #define dictFreeEntryVal(d, entry) \
  98     if ((d)->type->valDestructor) \
  99         (d)->type->valDestructor((d)->privdata, (entry)->v.val)
 100
 101 #define dictSetHashVal(d, entry, _val_) do { \
 102     if ((d)->type->valDup) \
 103         entry->v.val = (d)->type->valDup((d)->privdata, _val_); \
 104     else \
 105         entry->v.val = (_val_); \
 106 } while(0)
 107
 108 #define dictFreeEntryKey(d, entry) \
 109     if ((d)->type->keyDestructor) \
 110         (d)->type->keyDestructor((d)->privdata, (entry)->key)
 111
 112 #define dictSetHashKey(d, entry, _key_) do { \
 113     if ((d)->type->keyDup) \
 114         entry->key = (d)->type->keyDup((d)->privdata, _key_); \
 115     else \
 116         entry->key = (_key_); \
 117 } while(0)
 118
 119 #define dictCompareHashKeys(d, key1, key2) \
 120     (((d)->type->keyCompare) ? \
 121         (d)->type->keyCompare((d)->privdata, key1, key2) : \
 122         (key1) == (key2))
 123
 124 #define dictHashKey(d, key) (d)->type->hashFunction(key)
 125
 126 #define dictGetEntryKey(he) ((he)->key)
 127 #define dictGetEntryVal(he) ((he)->v.val)
 128 #define dictSlots(d) ((d)->ht[0].size+(d)->ht[1].size)
 129 #define dictSize(d) ((d)->ht[0].used+(d)->ht[1].used)
 130 #define dictIsRehashing(ht) ((ht)->rehashidx != -1)
 131
 132 /* API */
 133 dict *dictCreate(dictType *type, void *privDataPtr);
 134 int dictExpand(dict *d, unsigned long size);
 135 int dictAdd(dict *d, void *key, void *val);
 136 int dictReplace(dict *d, void *key, void *val);
 137 int dictDelete(dict *d, const void *key);
 138 int dictDeleteNoFree(dict *d, const void *key);
 139 void dictRelease(dict *d);
 140 dictEntry * dictFind(dict *d, const void *key);
 141 void *dictFetchValue(dict *d, const void *key);
 142 int dictResize(dict *d);
 143 dictIterator *dictGetIterator(dict *d);
 144 dictIterator *dictGetSafeIterator(dict *d);
 145 dictEntry *dictNext(dictIterator *iter);
 146 void dictReleaseIterator(dictIterator *iter);
 147 dictEntry *dictGetRandomKey(dict *d);
 148 void dictPrintStats(dict *d);
 149 unsigned int dictGenHashFunction(const unsigned char *buf, int len);
 150 unsigned int dictGenCaseHashFunction(const unsigned char *buf, int len);
 151 void dictEmpty(dict *d);
 152 void dictEnableResize(void);
 153 void dictDisableResize(void);
 154 int dictRehash(dict *d, int n);
 155 int dictRehashMilliseconds(dict *d, int ms);
 156
 157 /* Hash table types */
 158 extern dictType dictTypeHeapStringCopyKey;
 159 extern dictType dictTypeHeapStrings;
 160 extern dictType dictTypeHeapStringCopyKeyValue;
 161
 162 #endif /* __DICT_H */