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 s64;
  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 dictFreeVal(d, entry) \
  98     if ((d)->type->valDestructor) \
  99         (d)->type->valDestructor((d)->privdata, (entry)->v.val)
 100
 101 #define dictSetVal(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 dictSetSignedIntegerVal(entry, _val_) \
 109     do { entry->v.s64 = _val_; } while(0)
 110
 111 #define dictSetUnsignedIntegerVal(entry, _val_) \
 112     do { entry->v.u64 = _val_; } while(0)
 113
 114 #define dictFreeKey(d, entry) \
 115     if ((d)->type->keyDestructor) \
 116         (d)->type->keyDestructor((d)->privdata, (entry)->key)
 117
 118 #define dictSetKey(d, entry, _key_) do { \
 119     if ((d)->type->keyDup) \
 120         entry->key = (d)->type->keyDup((d)->privdata, _key_); \
 121     else \
 122         entry->key = (_key_); \
 123 } while(0)
 124
 125 #define dictCompareKeys(d, key1, key2) \
 126     (((d)->type->keyCompare) ? \
 127         (d)->type->keyCompare((d)->privdata, key1, key2) : \
 128         (key1) == (key2))
 129
 130 #define dictHashKey(d, key) (d)->type->hashFunction(key)
 131 #define dictGetKey(he) ((he)->key)
 132 #define dictGetVal(he) ((he)->v.val)
 133 #define dictGetSignedIntegerVal(he) ((he)->v.s64)
 134 #define dictGetUnsignedIntegerVal(he) ((he)->v.u64)
 135 #define dictSlots(d) ((d)->ht[0].size+(d)->ht[1].size)
 136 #define dictSize(d) ((d)->ht[0].used+(d)->ht[1].used)
 137 #define dictIsRehashing(ht) ((ht)->rehashidx != -1)
 138
 139 /* API */
 140 dict *dictCreate(dictType *type, void *privDataPtr);
 141 int dictExpand(dict *d, unsigned long size);
 142 int dictAdd(dict *d, void *key, void *val);
 143 dictEntry *dictAddRaw(dict *d, void *key);
 144 int dictReplace(dict *d, void *key, void *val);
 145 dictEntry *dictReplaceRaw(dict *d, void *key);
 146 int dictDelete(dict *d, const void *key);
 147 int dictDeleteNoFree(dict *d, const void *key);
 148 void dictRelease(dict *d);
 149 dictEntry * dictFind(dict *d, const void *key);
 150 void *dictFetchValue(dict *d, const void *key);
 151 int dictResize(dict *d);
 152 dictIterator *dictGetIterator(dict *d);
 153 dictIterator *dictGetSafeIterator(dict *d);
 154 dictEntry *dictNext(dictIterator *iter);
 155 void dictReleaseIterator(dictIterator *iter);
 156 dictEntry *dictGetRandomKey(dict *d);
 157 void dictPrintStats(dict *d);
 158 unsigned int dictGenHashFunction(const unsigned char *buf, int len);
 159 unsigned int dictGenCaseHashFunction(const unsigned char *buf, int len);
 160 void dictEmpty(dict *d);
 161 void dictEnableResize(void);
 162 void dictDisableResize(void);
 163 int dictRehash(dict *d, int n);
 164 int dictRehashMilliseconds(dict *d, int ms);
 165
 166 /* Hash table types */
 167 extern dictType dictTypeHeapStringCopyKey;
 168 extern dictType dictTypeHeapStrings;
 169 extern dictType dictTypeHeapStringCopyKeyValue;
 170
 171 #endif /* __DICT_H */