text: /* Hash table implementation.
   *
   * This file implements in memory hash tables with insert/del/replace/find/
   * get-random-element operations. Hash tables will auto resize if needed
   * tables of power of two in size are used, collisions are handled by
   * chaining. See the source code for more information... :)
   *
   * Copyright (c) 2006-2010, Salvatore Sanfilippo <antirez at gmail dot com>
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   *   * Redistributions of source code must retain the above copyright notice,
   *     this list of conditions and the following disclaimer.
   *   * Redistributions in binary form must reproduce the above copyright
   *     notice, this list of conditions and the following disclaimer in the
   *     documentation and/or other materials provided with the distribution.
   *   * Neither the name of Redis nor the names of its contributors may be used
   *     to endorse or promote products derived from this software without
   *     specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  #ifndef __DICT_H
  #define __DICT_H
  
  #define DICT_OK 0
  #define DICT_ERR 1
  
  /* Unused arguments generate annoying warnings... */
  #define DICT_NOTUSED(V) ((void) V)
  
  typedef struct dictEntry {
      void *key;
      void *val;
      struct dictEntry *next;
  } dictEntry;
  
  typedef struct dictType {
      unsigned int (*hashFunction)(const void *key);
      void *(*keyDup)(void *privdata, const void *key);
      void *(*valDup)(void *privdata, const void *obj);
      int (*keyCompare)(void *privdata, const void *key1, const void *key2);
      void (*keyDestructor)(void *privdata, void *key);
      void (*valDestructor)(void *privdata, void *obj);
  } dictType;
  
  typedef struct dict {
      dictEntry **table;
      dictType *type;
      unsigned long size;
      unsigned long sizemask;
      unsigned long used;
      void *privdata;
  } dict;
  
  typedef struct dictIterator {
      dict *ht;
      int index;
      dictEntry *entry, *nextEntry;
  } dictIterator;
  
  /* This is the initial size of every hash table */
  #define DICT_HT_INITIAL_SIZE     4
  
  /* ------------------------------- Macros ------------------------------------*/
  #define dictFreeEntryVal(ht, entry) \
      if ((ht)->type->valDestructor) \
          (ht)->type->valDestructor((ht)->privdata, (entry)->val)
  
  #define dictSetHashVal(ht, entry, _val_) do { \
      if ((ht)->type->valDup) \
          entry->val = (ht)->type->valDup((ht)->privdata, _val_); \
      else \
          entry->val = (_val_); \
  } while(0)
  
  #define dictFreeEntryKey(ht, entry) \
      if ((ht)->type->keyDestructor) \
          (ht)->type->keyDestructor((ht)->privdata, (entry)->key)
  
  #define dictSetHashKey(ht, entry, _key_) do { \
      if ((ht)->type->keyDup) \
          entry->key = (ht)->type->keyDup((ht)->privdata, _key_); \
      else \
          entry->key = (_key_); \
  } while(0)
  
  #define dictCompareHashKeys(ht, key1, key2) \
      (((ht)->type->keyCompare) ? \
          (ht)->type->keyCompare((ht)->privdata, key1, key2) : \
          (key1) == (key2))
  
  // 计算key的hash值
  #define dictHashKey(ht, key) (ht)->type->hashFunction(key)
  
  #define dictGetEntryKey(he) ((he)->key)
  #define dictGetEntryVal(he) ((he)->val)
  #define dictSlots(ht) ((ht)->size)
  #define dictSize(ht) ((ht)->used)
  
  /* API */
  static unsigned int dictGenHashFunction(const unsigned char *buf, int len);
  static dict *dictCreate(dictType *type, void *privDataPtr);
  static int dictExpand(dict *ht, unsigned long size);
  static int dictAdd(dict *ht, void *key, void *val);
  static int dictReplace(dict *ht, void *key, void *val);
  static int dictDelete(dict *ht, const void *key);
  static void dictRelease(dict *ht);
  static dictEntry * dictFind(dict *ht, const void *key);
  static dictIterator *dictGetIterator(dict *ht);
  static dictEntry *dictNext(dictIterator *iter);
  static void dictReleaseIterator(dictIterator *iter);
  
  #endif /* __DICT_H */
  