/* Hash Tables 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) 2006-2012, 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#include"mt19937-64.h"#include<limits.h>#include<stdint.h>#include<stdlib.h>#defineDICT_OK0#defineDICT_ERR1/* Unused arguments generate annoying warnings... */#defineDICT_NOTUSED(V)((void) V)typedefstructdictEntry{void*key;union{void*val;uint64_t u64;int64_t s64;double d;} v;structdictEntry*next;} dictEntry;typedefstructdictType{uint64_t(*hashFunction)(constvoid*key);void*(*keyDup)(void*privdata,constvoid*key);void*(*valDup)(void*privdata,constvoid*obj);int(*keyCompare)(void*privdata,constvoid*key1,constvoid*key2);void(*keyDestructor)(void*privdata,void*key);void(*valDestructor)(void*privdata,void*obj);int(*expandAllowed)(size_t moreMem,double usedRatio);} dictType;/* This is our hash table structure. Every dictionary has two of this as we* implement incremental rehashing, for the old to the new table. */typedefstructdictht{dictEntry **table;unsignedlong size;unsignedlong sizemask;unsignedlong used;} dictht;typedefstructdict{dictType *type;void*privdata;dictht ht[2];long rehashidx;/* rehashing not in progress if rehashidx == -1 */int16_t pauserehash;/* If >0 rehashing is paused (<0 indicates coding error) */} dict;/* If safe is set to 1 this is a safe iterator, that means, you can call* dictAdd, dictFind, and other functions against the dictionary even while* iterating. Otherwise it is a non safe iterator, and only dictNext()* should be called while iterating. */typedefstructdictIterator{dict *d;long index;int table, safe;dictEntry *entry,*nextEntry;/* unsafe iterator fingerprint for misuse detection. */unsignedlonglong fingerprint;} dictIterator;typedefvoid(dictScanFunction)(void*privdata,const dictEntry *de);typedefvoid(dictScanBucketFunction)(void*privdata, dictEntry **bucketref);/* This is the initial size of every hash table */#defineDICT_HT_INITIAL_SIZE4/* ------------------------------- Macros ------------------------------------*/#definedictFreeVal(d, entry)\if((d)->type->valDestructor)\(d)->type->valDestructor((d)->privdata,(entry)->v.val)#definedictSetVal(d, entry, _val_)do{\if((d)->type->valDup)\(entry)->v.val =(d)->type->valDup((d)->privdata, _val_);\else\(entry)->v.val =(_val_);\}while(0)#definedictSetSignedIntegerVal(entry, _val_)\do{(entry)->v.s64 = _val_;}while(0)#definedictSetUnsignedIntegerVal(entry, _val_)\do{(entry)->v.u64 = _val_;}while(0)#definedictSetDoubleVal(entry, _val_)\do{(entry)->v.d = _val_;}while(0)#definedictFreeKey(d, entry)\if((d)->type->keyDestructor)\(d)->type->keyDestructor((d)->privdata,(entry)->key)#definedictSetKey(d, entry, _key_)do{\if((d)->type->keyDup)\(entry)->key =(d)->type->keyDup((d)->privdata, _key_);\else\(entry)->key =(_key_);\}while(0)#definedictCompareKeys(d, key1, key2)\(((d)->type->keyCompare)?\(d)->type->keyCompare((d)->privdata, key1, key2):\(key1)==(key2))#definedictHashKey(d, key)(d)->type->hashFunction(key)#definedictGetKey(he)((he)->key)#definedictGetVal(he)((he)->v.val)#definedictGetSignedIntegerVal(he)((he)->v.s64)#definedictGetUnsignedIntegerVal(he)((he)->v.u64)#definedictGetDoubleVal(he)((he)->v.d)#definedictSlots(d)((d)->ht[0].size+(d)->ht[1].size)#definedictSize(d)((d)->ht[0].used+(d)->ht[1].used)#definedictIsRehashing(d)((d)->rehashidx !=-1)#definedictPauseRehashing(d)(d)->pauserehash++#definedictResumeRehashing(d)(d)->pauserehash--/* If our unsigned long type can store a 64 bit number, use a 64 bit PRNG. */#ifULONG_MAX >=0xffffffffffffffff#definerandomULong()((unsignedlong)genrand64_int64())#else#definerandomULong()random()#endiftypedefenum{DICT_RESIZE_ENABLE,DICT_RESIZE_AVOID,DICT_RESIZE_FORBID,} dictResizeEnable;/* API */
dict *dictCreate(dictType *type,void*privDataPtr);intdictExpand(dict *d,unsignedlong size);intdictTryExpand(dict *d,unsignedlong size);intdictAdd(dict *d,void*key,void*val);
dictEntry *dictAddRaw(dict *d,void*key, dictEntry **existing);
dictEntry *dictAddOrFind(dict *d,void*key);intdictReplace(dict *d,void*key,void*val);intdictDelete(dict *d,constvoid*key);
dictEntry *dictUnlink(dict *ht,constvoid*key);voiddictFreeUnlinkedEntry(dict *d, dictEntry *he);voiddictRelease(dict *d);
dictEntry *dictFind(dict *d,constvoid*key);void*dictFetchValue(dict *d,constvoid*key);intdictResize(dict *d);
dictIterator *dictGetIterator(dict *d);
dictIterator *dictGetSafeIterator(dict *d);
dictEntry *dictNext(dictIterator *iter);voiddictReleaseIterator(dictIterator *iter);
dictEntry *dictGetRandomKey(dict *d);
dictEntry *dictGetFairRandomKey(dict *d);unsignedintdictGetSomeKeys(dict *d, dictEntry **des,unsignedint count);voiddictGetStats(char*buf,size_t bufsize, dict *d);uint64_tdictGenHashFunction(constvoid*key,int len);uint64_tdictGenCaseHashFunction(constunsignedchar*buf,int len);voiddictEmpty(dict *d,void(callback)(void*));voiddictSetResizeEnabled(dictResizeEnable enable);intdictRehash(dict *d,int n);intdictRehashMilliseconds(dict *d,int ms);voiddictSetHashFunctionSeed(uint8_t*seed);uint8_t*dictGetHashFunctionSeed(void);unsignedlongdictScan(dict *d,unsignedlong v, dictScanFunction *fn, dictScanBucketFunction *bucketfn,void*privdata);uint64_tdictGetHash(dict *d,constvoid*key);
dictEntry **dictFindEntryRefByPtrAndHash(dict *d,constvoid*oldptr,uint64_t hash);/* Hash table types */extern dictType dictTypeHeapStringCopyKey;extern dictType dictTypeHeapStrings;extern dictType dictTypeHeapStringCopyKeyValue;#ifdefREDIS_TESTintdictTest(int argc,char*argv[],int accurate);#endif/* defined by blogger */#definezcalloc(n)calloc(n,sizeof(char))#definezmallocmalloc#definezfreefree#defineztrycalloczcalloc#endif/* __DICT_H */
/* Hash Tables 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) 2006-2012, 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.*///#include "fmacros.h"#include<stdio.h>#include<stdlib.h>#include<stdint.h>#include<string.h>#include<stdarg.h>#include<limits.h>#include<sys/time.h>#include<assert.h>#include"dict.h"//#include "zmalloc.h"//#include "redisassert.h"/* Using dictEnableResize() / dictDisableResize() we make possible to disable* resizing and rehashing of the hash table as needed. This is very important* for Redis, as we use copy-on-write and don't want to move too much memory* around when there is a child performing saving operations.** Note that even when dict_can_resize is set to 0, not all resizes are* prevented: a hash table is still allowed to grow if the ratio between* the number of elements and the buckets > dict_force_resize_ratio. */static dictResizeEnable dict_can_resize = DICT_RESIZE_ENABLE;staticunsignedint dict_force_resize_ratio =5;/* -------------------------- private prototypes ---------------------------- */staticint_dictExpandIfNeeded(dict *ht);staticunsignedlong_dictNextPower(unsignedlong size);staticlong_dictKeyIndex(dict *ht,constvoid*key,uint64_t hash, dictEntry **existing);staticint_dictInit(dict *ht, dictType *type,void*privDataPtr);/* -------------------------- hash functions -------------------------------- */staticuint8_t dict_hash_function_seed[16];voiddictSetHashFunctionSeed(uint8_t*seed){memcpy(dict_hash_function_seed,seed,sizeof(dict_hash_function_seed));}uint8_t*dictGetHashFunctionSeed(void){return dict_hash_function_seed;}/* The default hashing function uses SipHash implementation* in siphash.c. */uint64_tsiphash(constuint8_t*in,constsize_t inlen,constuint8_t*k);uint64_tsiphash_nocase(constuint8_t*in,constsize_t inlen,constuint8_t*k);uint64_tdictGenHashFunction(constvoid*key,int len){returnsiphash(key,len,dict_hash_function_seed);}uint64_tdictGenCaseHashFunction(constunsignedchar*buf,int len){returnsiphash_nocase(buf,len,dict_hash_function_seed);}/* ----------------------------- API implementation ------------------------- *//* Reset a hash table already initialized with ht_init().* NOTE: This function should only be called by ht_destroy(). */staticvoid_dictReset(dictht *ht){ht->table =NULL;ht->size =0;ht->sizemask =0;ht->used =0;}/* Create a new hash table */
dict *dictCreate(dictType *type,void*privDataPtr){dict *d =zmalloc(sizeof(*d));_dictInit(d,type,privDataPtr);return d;}/* Initialize the hash table */int_dictInit(dict *d, dictType *type,void*privDataPtr){_dictReset(&d->ht[0]);_dictReset(&d->ht[1]);d->type = type;d->privdata = privDataPtr;d->rehashidx =-1;d->pauserehash =0;return DICT_OK;}/* Resize the table to the minimal size that contains all the elements,* but with the invariant of a USED/BUCKETS ratio near to <= 1 */intdictResize(dict *d){unsignedlong minimal;if(dict_can_resize != DICT_RESIZE_ENABLE ||dictIsRehashing(d))return DICT_ERR;minimal = d->ht[0].used;if(minimal < DICT_HT_INITIAL_SIZE)minimal = DICT_HT_INITIAL_SIZE;returndictExpand(d, minimal);}/* Expand or create the hash table,* when malloc_failed is non-NULL, it'll avoid panic if malloc fails (in which case it'll be set to 1).* Returns DICT_OK if expand was performed, and DICT_ERR if skipped. */int_dictExpand(dict *d,unsignedlong size,int* malloc_failed){if(malloc_failed)*malloc_failed =0;/* the size is invalid if it is smaller than the number of* elements already inside the hash table */if(dictIsRehashing(d)|| d->ht[0].used > size)return DICT_ERR;dictht n;/* the new hash table */unsignedlong realsize =_dictNextPower(size);/* Detect overflows */if(realsize < size || realsize *sizeof(dictEntry*)< realsize)return DICT_ERR;/* Rehashing to the same table size is not useful. */if(realsize == d->ht[0].size)return DICT_ERR;/* Allocate the new hash table and initialize all pointers to NULL */n.size = realsize;n.sizemask = realsize-1;if(malloc_failed){n.table =ztrycalloc(realsize*sizeof(dictEntry*));*malloc_failed = n.table ==NULL;if(*malloc_failed)return DICT_ERR;}elsen.table =zcalloc(realsize*sizeof(dictEntry*));n.used =0;/* Is this the first initialization? If so it's not really a rehashing* we just set the first hash table so that it can accept keys. */if(d->ht[0].table ==NULL){d->ht[0]= n;return DICT_OK;}/* Prepare a second hash table for incremental rehashing */d->ht[1]= n;d->rehashidx =0;return DICT_OK;}/* return DICT_ERR if expand was not performed */intdictExpand(dict *d,unsignedlong size){return_dictExpand(d, size,NULL);}/* return DICT_ERR if expand failed due to memory allocation failure */intdictTryExpand(dict *d,unsignedlong size){int malloc_failed;_dictExpand(d, size,&malloc_failed);return malloc_failed? DICT_ERR : DICT_OK;}/* Performs N steps of incremental rehashing. Returns 1 if there are still* keys to move from the old to the new hash table, otherwise 0 is returned.** Note that a rehashing step consists in moving a bucket (that may have more* than one key as we use chaining) from the old to the new hash table, however* since part of the hash table may be composed of empty spaces, it is not* guaranteed that this function will rehash even a single bucket, since it* will visit at max N*10 empty buckets in total, otherwise the amount of* work it does would be unbound and the function may block for a long time. */intdictRehash(dict *d,int n){int empty_visits = n*10;/* Max number of empty buckets to visit. */unsignedlong s0 = d->ht[0].size;unsignedlong s1 = d->ht[1].size;if(dict_can_resize == DICT_RESIZE_FORBID ||!dictIsRehashing(d))return0;if(dict_can_resize == DICT_RESIZE_AVOID &&((s1 > s0 && s1 / s0 < dict_force_resize_ratio)||(s1 < s0 && s0 / s1 < dict_force_resize_ratio))){return0;}while(n--&& d->ht[0].used !=0){dictEntry *de,*nextde;/* Note that rehashidx can't overflow as we are sure there are more* elements because ht[0].used != 0 */assert(d->ht[0].size >(unsignedlong)d->rehashidx);while(d->ht[0].table[d->rehashidx]==NULL){d->rehashidx++;if(--empty_visits ==0)return1;}de = d->ht[0].table[d->rehashidx];/* Move all the keys in this bucket from the old to the new hash HT */while(de){uint64_t h;nextde = de->next;/* Get the index in the new hash table */h =dictHashKey(d, de->key)& d->ht[1].sizemask;de->next = d->ht[1].table[h];d->ht[1].table[h]= de;d->ht[0].used--;d->ht[1].used++;de = nextde;}d->ht[0].table[d->rehashidx]=NULL;d->rehashidx++;}/* Check if we already rehashed the whole table... */if(d->ht[0].used ==0){zfree(d->ht[0].table);d->ht[0]= d->ht[1];_dictReset(&d->ht[1]);d->rehashidx =-1;return0;}/* More to rehash... */return1;}longlongtimeInMilliseconds(void){structtimeval tv;gettimeofday(&tv,NULL);return(((longlong)tv.tv_sec)*1000)+(tv.tv_usec/1000);}/* Rehash in ms+"delta" milliseconds. The value of "delta" is larger * than 0, and is smaller than 1 in most cases. The exact upper bound * depends on the running time of dictRehash(d,100).*/intdictRehashMilliseconds(dict *d,int ms){if(d->pauserehash >0)return0;longlong start =timeInMilliseconds();int rehashes =0;while(dictRehash(d,100)){rehashes +=100;if(timeInMilliseconds()-start > ms)break;}return rehashes;}/* This function performs just a step of rehashing, and only if hashing has* not been paused for our hash table. When we have iterators in the* middle of a rehashing we can't mess with the two hash tables otherwise* some element can be missed or duplicated.** This function is called by common lookup or update operations in the* dictionary so that the hash table automatically migrates from H1 to H2* while it is actively used. */staticvoid_dictRehashStep(dict *d){if(d->pauserehash ==0)dictRehash(d,1);}/* Add an element to the target hash table */intdictAdd(dict *d,void*key,void*val){dictEntry *entry =dictAddRaw(d,key,NULL);if(!entry)return DICT_ERR;dictSetVal(d, entry, val);return DICT_OK;}/* Low level add or find:* This function adds the entry but instead of setting a value returns the* dictEntry structure to the user, that will make sure to fill the value* field as they wish.** This function is also directly exposed to the user API to be called* mainly in order to store non-pointers inside the hash value, example:** entry = dictAddRaw(dict,mykey,NULL);* if (entry != NULL) dictSetSignedIntegerVal(entry,1000);** Return values:** If key already exists NULL is returned, and "*existing" is populated* with the existing entry if existing is not NULL.** If key was added, the hash entry is returned to be manipulated by the caller.*/
dictEntry *dictAddRaw(dict *d,void*key, dictEntry **existing){long index;dictEntry *entry;dictht *ht;if(dictIsRehashing(d))_dictRehashStep(d);/* Get the index of the new element, or -1 if* the element already exists. */if((index =_dictKeyIndex(d, key,dictHashKey(d,key), existing))==-1)returnNULL;/* Allocate the memory and store the new entry.* Insert the element in top, with the assumption that in a database* system it is more likely that recently added entries are accessed* more frequently. */ht =dictIsRehashing(d)?&d->ht[1]:&d->ht[0];entry =zmalloc(sizeof(*entry));entry->next = ht->table[index];ht->table[index]= entry;ht->used++;/* Set the hash entry fields. */dictSetKey(d, entry, key);return entry;}/* Add or Overwrite:* Add an element, discarding the old value if the key already exists.* Return 1 if the key was added from scratch, 0 if there was already an* element with such key and dictReplace() just performed a value update* operation. */intdictReplace(dict *d,void*key,void*val){dictEntry *entry,*existing, auxentry;/* Try to add the element. If the key* does not exists dictAdd will succeed. */entry =dictAddRaw(d,key,&existing);if(entry){dictSetVal(d, entry, val);return1;}/* Set the new value and free the old one. Note that it is important* to do that in this order, as the value may just be exactly the same* as the previous one. In this context, think to reference counting,* you want to increment (set), and then decrement (free), and not the* reverse. */auxentry =*existing;dictSetVal(d, existing, val);dictFreeVal(d,&auxentry);return0;}/* Add or Find:* dictAddOrFind() is simply a version of dictAddRaw() that always* returns the hash entry of the specified key, even if the key already* exists and can't be added (in that case the entry of the already* existing key is returned.)** See dictAddRaw() for more information. */
dictEntry *dictAddOrFind(dict *d,void*key){dictEntry *entry,*existing;entry =dictAddRaw(d,key,&existing);return entry ? entry : existing;}/* Search and remove an element. This is an helper function for* dictDelete() and dictUnlink(), please check the top comment* of those functions. */static dictEntry *dictGenericDelete(dict *d,constvoid*key,int nofree){uint64_t h, idx;dictEntry *he,*prevHe;int table;if(d->ht[0].used ==0&& d->ht[1].used ==0)returnNULL;if(dictIsRehashing(d))_dictRehashStep(d);h =dictHashKey(d, key);for(table =0; table <=1; table++){idx = h & d->ht[table].sizemask;he = d->ht[table].table[idx];prevHe =NULL;while(he){if(key==he->key ||dictCompareKeys(d, key, he->key)){/* Unlink the element from the list */if(prevHe)prevHe->next = he->next;elsed->ht[table].table[idx]= he->next;if(!nofree){dictFreeKey(d, he);dictFreeVal(d, he);zfree(he);}d->ht[table].used--;return he;}prevHe = he;he = he->next;}if(!dictIsRehashing(d))break;}returnNULL;/* not found */}/* Remove an element, returning DICT_OK on success or DICT_ERR if the* element was not found. */intdictDelete(dict *ht,constvoid*key){returndictGenericDelete(ht,key,0)? DICT_OK : DICT_ERR;}/* Remove an element from the table, but without actually releasing* the key, value and dictionary entry. The dictionary entry is returned* if the element was found (and unlinked from the table), and the user* should later call `dictFreeUnlinkedEntry()` with it in order to release it.* Otherwise if the key is not found, NULL is returned.** This function is useful when we want to remove something from the hash* table but want to use its value before actually deleting the entry.* Without this function the pattern would require two lookups:** entry = dictFind(...);* // Do something with entry* dictDelete(dictionary,entry);** Thanks to this function it is possible to avoid this, and use* instead:** entry = dictUnlink(dictionary,entry);* // Do something with entry* dictFreeUnlinkedEntry(entry); // <- This does not need to lookup again.*/
dictEntry *dictUnlink(dict *ht,constvoid*key){returndictGenericDelete(ht,key,1);}/* You need to call this function to really free the entry after a call* to dictUnlink(). It's safe to call this function with 'he' = NULL. */voiddictFreeUnlinkedEntry(dict *d, dictEntry *he){if(he ==NULL)return;dictFreeKey(d, he);dictFreeVal(d, he);zfree(he);}/* Destroy an entire dictionary */int_dictClear(dict *d, dictht *ht,void(callback)(void*)){unsignedlong i;/* Free all the elements */for(i =0; i < ht->size && ht->used >0; i++){dictEntry *he,*nextHe;if(callback &&(i &65535)==0)callback(d->privdata);if((he = ht->table[i])==NULL)continue;while(he){nextHe = he->next;dictFreeKey(d, he);dictFreeVal(d, he);zfree(he);ht->used--;he = nextHe;}}/* Free the table and the allocated cache structure */zfree(ht->table);/* Re-initialize the table */_dictReset(ht);return DICT_OK;/* never fails */}/* Clear & Release the hash table */voiddictRelease(dict *d){_dictClear(d,&d->ht[0],NULL);_dictClear(d,&d->ht[1],NULL);zfree(d);}dictEntry *dictFind(dict *d,constvoid*key){dictEntry *he;uint64_t h, idx, table;if(dictSize(d)==0)returnNULL;/* dict is empty */if(dictIsRehashing(d))_dictRehashStep(d);h =dictHashKey(d, key);for(table =0; table <=1; table++){idx = h & d->ht[table].sizemask;he = d->ht[table].table[idx];while(he){if(key==he->key ||dictCompareKeys(d, key, he->key))return he;he = he->next;}if(!dictIsRehashing(d))returnNULL;}returnNULL;}void*dictFetchValue(dict *d,constvoid*key){dictEntry *he;he =dictFind(d,key);return he ?dictGetVal(he):NULL;}/* A fingerprint is a 64 bit number that represents the state of the dictionary* at a given time, it's just a few dict properties xored together.* When an unsafe iterator is initialized, we get the dict fingerprint, and check* the fingerprint again when the iterator is released.* If the two fingerprints are different it means that the user of the iterator* performed forbidden operations against the dictionary while iterating. */unsignedlonglongdictFingerprint(dict *d){unsignedlonglong integers[6], hash =0;int j;integers[0]=(long) d->ht[0].table;integers[1]= d->ht[0].size;integers[2]= d->ht[0].used;integers[3]=(long) d->ht[1].table;integers[4]= d->ht[1].size;integers[5]= d->ht[1].used;/* We hash N integers by summing every successive integer with the integer* hashing of the previous sum. Basically:** Result = hash(hash(hash(int1)+int2)+int3) ...** This way the same set of integers in a different order will (likely) hash* to a different number. */for(j =0; j <6; j++){hash += integers[j];/* For the hashing step we use Tomas Wang's 64 bit integer hash. */hash =(~hash)+(hash <<21);// hash = (hash << 21) - hash - 1;hash = hash ^(hash >>24);hash =(hash +(hash <<3))+(hash <<8);// hash * 265hash = hash ^(hash >>14);hash =(hash +(hash <<2))+(hash <<4);// hash * 21hash = hash ^(hash >>28);hash = hash +(hash <<31);}return hash;}dictIterator *dictGetIterator(dict *d){dictIterator *iter =zmalloc(sizeof(*iter));iter->d = d;iter->table =0;iter->index =-1;iter->safe =0;iter->entry =NULL;iter->nextEntry =NULL;return iter;}dictIterator *dictGetSafeIterator(dict *d){dictIterator *i =dictGetIterator(d);i->safe =1;return i;}dictEntry *dictNext(dictIterator *iter){while(1){if(iter->entry ==NULL){dictht *ht =&iter->d->ht[iter->table];if(iter->index ==-1&& iter->table ==0){if(iter->safe)dictPauseRehashing(iter->d);elseiter->fingerprint =dictFingerprint(iter->d);}iter->index++;if(iter->index >=(long) ht->size){if(dictIsRehashing(iter->d)&& iter->table ==0){iter->table++;iter->index =0;ht =&iter->d->ht[1];}else{break;}}iter->entry = ht->table[iter->index];}else{iter->entry = iter->nextEntry;}if(iter->entry){/* We need to save the 'next' here, the iterator user* may delete the entry we are returning. */iter->nextEntry = iter->entry->next;return iter->entry;}}returnNULL;}voiddictReleaseIterator(dictIterator *iter){if(!(iter->index ==-1&& iter->table ==0)){if(iter->safe)dictResumeRehashing(iter->d);elseassert(iter->fingerprint ==dictFingerprint(iter->d));}zfree(iter);}/* Return a random entry from the hash table. Useful to* implement randomized algorithms */
dictEntry *dictGetRandomKey(dict *d){dictEntry *he,*orighe;unsignedlong h;int listlen, listele;if(dictSize(d)==0)returnNULL;if(dictIsRehashing(d))_dictRehashStep(d);if(dictIsRehashing(d)){do{/* We are sure there are no elements in indexes from 0* to rehashidx-1 */h = d->rehashidx +(randomULong()%(dictSlots(d)- d->rehashidx));he =(h >= d->ht[0].size)? d->ht[1].table[h - d->ht[0].size]:d->ht[0].table[h];}while(he ==NULL);}else{do{h =randomULong()& d->ht[0].sizemask;he = d->ht[0].table[h];}while(he ==NULL);}/* Now we found a non empty bucket, but it is a linked* list and we need to get a random element from the list.* The only sane way to do so is counting the elements and* select a random index. */listlen =0;orighe = he;while(he){he = he->next;listlen++;}listele =random()% listlen;he = orighe;while(listele--) he = he->next;return he;}/* This function samples the dictionary to return a few keys from random* locations.** It does not guarantee to return all the keys specified in 'count', nor* it does guarantee to return non-duplicated elements, however it will make* some effort to do both things.** Returned pointers to hash table entries are stored into 'des' that* points to an array of dictEntry pointers. The array must have room for* at least 'count' elements, that is the argument we pass to the function* to tell how many random elements we need.** The function returns the number of items stored into 'des', that may* be less than 'count' if the hash table has less than 'count' elements* inside, or if not enough elements were found in a reasonable amount of* steps.** Note that this function is not suitable when you need a good distribution* of the returned items, but only when you need to "sample" a given number* of continuous elements to run some kind of algorithm or to produce* statistics. However the function is much faster than dictGetRandomKey()* at producing N elements. */unsignedintdictGetSomeKeys(dict *d, dictEntry **des,unsignedint count){unsignedlong j;/* internal hash table id, 0 or 1. */unsignedlong tables;/* 1 or 2 tables? */unsignedlong stored =0, maxsizemask;unsignedlong maxsteps;if(dictSize(d)< count) count =dictSize(d);maxsteps = count*10;/* Try to do a rehashing work proportional to 'count'. */for(j =0; j < count; j++){if(dictIsRehashing(d))_dictRehashStep(d);elsebreak;}tables =dictIsRehashing(d)?2:1;maxsizemask = d->ht[0].sizemask;if(tables >1&& maxsizemask < d->ht[1].sizemask)maxsizemask = d->ht[1].sizemask;/* Pick a random point inside the larger table. */unsignedlong i =randomULong()& maxsizemask;unsignedlong emptylen =0;/* Continuous empty entries so far. */while(stored < count && maxsteps--){for(j =0; j < tables; j++){/* Invariant of the dict.c rehashing: up to the indexes already* visited in ht[0] during the rehashing, there are no populated* buckets, so we can skip ht[0] for indexes between 0 and idx-1. */if(tables ==2&& j ==0&& i <(unsignedlong) d->rehashidx){/* Moreover, if we are currently out of range in the second* table, there will be no elements in both tables up to* the current rehashing index, so we jump if possible.* (this happens when going from big to small table). */if(i >= d->ht[1].size)i = d->rehashidx;elsecontinue;}if(i >= d->ht[j].size)continue;/* Out of range for this table. */dictEntry *he = d->ht[j].table[i];/* Count contiguous empty buckets, and jump to other* locations if they reach 'count' (with a minimum of 5). */if(he ==NULL){emptylen++;if(emptylen >=5&& emptylen > count){i =randomULong()& maxsizemask;emptylen =0;}}else{emptylen =0;while(he){/* Collect all the elements of the buckets found non* empty while iterating. */*des = he;des++;he = he->next;stored++;if(stored == count)return stored;}}}i =(i+1)& maxsizemask;}return stored;}/* This is like dictGetRandomKey() from the POV of the API, but will do more* work to ensure a better distribution of the returned element.** This function improves the distribution because the dictGetRandomKey()* problem is that it selects a random bucket, then it selects a random* element from the chain in the bucket. However elements being in different* chain lengths will have different probabilities of being reported. With* this function instead what we do is to consider a "linear" range of the table* that may be constituted of N buckets with chains of different lengths* appearing one after the other. Then we report a random element in the range.* In this way we smooth away the problem of different chain lengths. */#defineGETFAIR_NUM_ENTRIES15
dictEntry *dictGetFairRandomKey(dict *d){dictEntry *entries[GETFAIR_NUM_ENTRIES];unsignedint count =dictGetSomeKeys(d,entries,GETFAIR_NUM_ENTRIES);/* Note that dictGetSomeKeys() may return zero elements in an unlucky* run() even if there are actually elements inside the hash table. So* when we get zero, we call the true dictGetRandomKey() that will always* yield the element if the hash table has at least one. */if(count ==0)returndictGetRandomKey(d);unsignedint idx =rand()% count;return entries[idx];}/* Function to reverse bits. Algorithm from:* http://graphics.stanford.edu/~seander/bithacks.html#ReverseParallel */staticunsignedlongrev(unsignedlong v){unsignedlong s = CHAR_BIT *sizeof(v);// bit size; must be power of 2unsignedlong mask =~0UL;while((s >>=1)>0){mask ^=(mask << s);v =((v >> s)& mask)|((v << s)&~mask);}return v;}/* dictScan() is used to iterate over the elements of a dictionary.** Iterating works the following way:** 1) Initially you call the function using a cursor (v) value of 0.* 2) The function performs one step of the iteration, and returns the* new cursor value you must use in the next call.* 3) When the returned cursor is 0, the iteration is complete.** The function guarantees all elements present in the* dictionary get returned between the start and end of the iteration.* However it is possible some elements get returned multiple times.** For every element returned, the callback argument 'fn' is* called with 'privdata' as first argument and the dictionary entry* 'de' as second argument.** HOW IT WORKS.** The iteration algorithm was designed by Pieter Noordhuis.* The main idea is to increment a cursor starting from the higher order* bits. That is, instead of incrementing the cursor normally, the bits* of the cursor are reversed, then the cursor is incremented, and finally* the bits are reversed again.** This strategy is needed because the hash table may be resized between* iteration calls.** dict.c hash tables are always power of two in size, and they* use chaining, so the position of an element in a given table is given* by computing the bitwise AND between Hash(key) and SIZE-1* (where SIZE-1 is always the mask that is equivalent to taking the rest* of the division between the Hash of the key and SIZE).** For example if the current hash table size is 16, the mask is* (in binary) 1111. The position of a key in the hash table will always be* the last four bits of the hash output, and so forth.** WHAT HAPPENS IF THE TABLE CHANGES IN SIZE?** If the hash table grows, elements can go anywhere in one multiple of* the old bucket: for example let's say we already iterated with* a 4 bit cursor 1100 (the mask is 1111 because hash table size = 16).** If the hash table will be resized to 64 elements, then the new mask will* be 111111. The new buckets you obtain by substituting in ??1100* with either 0 or 1 can be targeted only by keys we already visited* when scanning the bucket 1100 in the smaller hash table.** By iterating the higher bits first, because of the inverted counter, the* cursor does not need to restart if the table size gets bigger. It will* continue iterating using cursors without '1100' at the end, and also* without any other combination of the final 4 bits already explored.** Similarly when the table size shrinks over time, for example going from* 16 to 8, if a combination of the lower three bits (the mask for size 8* is 111) were already completely explored, it would not be visited again* because we are sure we tried, for example, both 0111 and 1111 (all the* variations of the higher bit) so we don't need to test it again.** WAIT... YOU HAVE *TWO* TABLES DURING REHASHING!** Yes, this is true, but we always iterate the smaller table first, then* we test all the expansions of the current cursor into the larger* table. For example if the current cursor is 101 and we also have a* larger table of size 16, we also test (0)101 and (1)101 inside the larger* table. This reduces the problem back to having only one table, where* the larger one, if it exists, is just an expansion of the smaller one.** LIMITATIONS** This iterator is completely stateless, and this is a huge advantage,* including no additional memory used.** The disadvantages resulting from this design are:** 1) It is possible we return elements more than once. However this is usually* easy to deal with in the application level.* 2) The iterator must return multiple elements per call, as it needs to always* return all the keys chained in a given bucket, and all the expansions, so* we are sure we don't miss keys moving during rehashing.* 3) The reverse cursor is somewhat hard to understand at first, but this* comment is supposed to help.*/unsignedlongdictScan(dict *d,unsignedlong v,dictScanFunction *fn,dictScanBucketFunction* bucketfn,void*privdata){dictht *t0,*t1;const dictEntry *de,*next;unsignedlong m0, m1;if(dictSize(d)==0)return0;/* This is needed in case the scan callback tries to do dictFind or alike. */dictPauseRehashing(d);if(!dictIsRehashing(d)){t0 =&(d->ht[0]);m0 = t0->sizemask;/* Emit entries at cursor */if(bucketfn)bucketfn(privdata,&t0->table[v & m0]);de = t0->table[v & m0];while(de){next = de->next;fn(privdata, de);de = next;}/* Set unmasked bits so incrementing the reversed cursor* operates on the masked bits */v |=~m0;/* Increment the reverse cursor */v =rev(v);v++;v =rev(v);}else{t0 =&d->ht[0];t1 =&d->ht[1];/* Make sure t0 is the smaller and t1 is the bigger table */if(t0->size > t1->size){t0 =&d->ht[1];t1 =&d->ht[0];}m0 = t0->sizemask;m1 = t1->sizemask;/* Emit entries at cursor */if(bucketfn)bucketfn(privdata,&t0->table[v & m0]);de = t0->table[v & m0];while(de){next = de->next;fn(privdata, de);de = next;}/* Iterate over indices in larger table that are the expansion* of the index pointed to by the cursor in the smaller table */do{/* Emit entries at cursor */if(bucketfn)bucketfn(privdata,&t1->table[v & m1]);de = t1->table[v & m1];while(de){next = de->next;fn(privdata, de);de = next;}/* Increment the reverse cursor not covered by the smaller mask.*/v |=~m1;v =rev(v);v++;v =rev(v);/* Continue while bits covered by mask difference is non-zero */}while(v &(m0 ^ m1));}dictResumeRehashing(d);return v;}/* ------------------------- private functions ------------------------------ *//* Because we may need to allocate huge memory chunk at once when dict* expands, we will check this allocation is allowed or not if the dict* type has expandAllowed member function. */staticintdictTypeExpandAllowed(dict *d){if(d->type->expandAllowed ==NULL)return1;return d->type->expandAllowed(_dictNextPower(d->ht[0].used +1)*sizeof(dictEntry*),(double)d->ht[0].used / d->ht[0].size);}/* Expand the hash table if needed */staticint_dictExpandIfNeeded(dict *d){/* Incremental rehashing already in progress. Return. */if(dictIsRehashing(d))return DICT_OK;/* If the hash table is empty expand it to the initial size. */if(d->ht[0].size ==0)returndictExpand(d, DICT_HT_INITIAL_SIZE);/* If we reached the 1:1 ratio, and we are allowed to resize the hash* table (global setting) or we should avoid it but the ratio between* elements/buckets is over the "safe" threshold, we resize doubling* the number of buckets. */if(!dictTypeExpandAllowed(d))return DICT_OK;if((dict_can_resize == DICT_RESIZE_ENABLE &&d->ht[0].used >= d->ht[0].size)||(dict_can_resize != DICT_RESIZE_FORBID &&d->ht[0].used / d->ht[0].size > dict_force_resize_ratio)){returndictExpand(d, d->ht[0].used +1);}return DICT_OK;}/* Our hash table capability is a power of two */staticunsignedlong_dictNextPower(unsignedlong size){unsignedlong i = DICT_HT_INITIAL_SIZE;if(size >= LONG_MAX)return LONG_MAX +1LU;while(1){if(i >= size)return i;i *=2;}}/* Returns the index of a free slot that can be populated with* a hash entry for the given 'key'.* If the key already exists, -1 is returned* and the optional output parameter may be filled.** Note that if we are in the process of rehashing the hash table, the* index is always returned in the context of the second (new) hash table. */staticlong_dictKeyIndex(dict *d,constvoid*key,uint64_t hash, dictEntry **existing){unsignedlong idx, table;dictEntry *he;if(existing)*existing =NULL;/* Expand the hash table if needed */if(_dictExpandIfNeeded(d)== DICT_ERR)return-1;for(table =0; table <=1; table++){idx = hash & d->ht[table].sizemask;/* Search if this slot does not already contain the given key */he = d->ht[table].table[idx];while(he){if(key==he->key ||dictCompareKeys(d, key, he->key)){if(existing)*existing = he;return-1;}he = he->next;}if(!dictIsRehashing(d))break;}return idx;}voiddictEmpty(dict *d,void(callback)(void*)){_dictClear(d,&d->ht[0],callback);_dictClear(d,&d->ht[1],callback);d->rehashidx =-1;d->pauserehash =0;}voiddictSetResizeEnabled(dictResizeEnable enable){dict_can_resize = enable;}uint64_tdictGetHash(dict *d,constvoid*key){returndictHashKey(d, key);}/* Finds the dictEntry reference by using pointer and pre-calculated hash.* oldkey is a dead pointer and should not be accessed.* the hash value should be provided using dictGetHash.* no string / key comparison is performed.* return value is the reference to the dictEntry if found, or NULL if not found. */
dictEntry **dictFindEntryRefByPtrAndHash(dict *d,constvoid*oldptr,uint64_t hash){dictEntry *he,**heref;unsignedlong idx, table;if(dictSize(d)==0)returnNULL;/* dict is empty */for(table =0; table <=1; table++){idx = hash & d->ht[table].sizemask;heref =&d->ht[table].table[idx];he =*heref;while(he){if(oldptr==he->key)return heref;heref =&he->next;he =*heref;}if(!dictIsRehashing(d))returnNULL;}returnNULL;}/* ------------------------------- Debugging ---------------------------------*/#defineDICT_STATS_VECTLEN50size_t_dictGetStatsHt(char*buf,size_t bufsize, dictht *ht,int tableid){unsignedlong i, slots =0, chainlen, maxchainlen =0;unsignedlong totchainlen =0;unsignedlong clvector[DICT_STATS_VECTLEN];size_t l =0;if(ht->used ==0){returnsnprintf(buf,bufsize,"Hash table %d stats (%s):\n""No stats available for empty dictionaries\n",tableid,(tableid ==0)?"main hash table":"rehashing target");}/* Compute stats. */for(i =0; i < DICT_STATS_VECTLEN; i++) clvector[i]=0;for(i =0; i < ht->size; i++){dictEntry *he;if(ht->table[i]==NULL){clvector[0]++;continue;}slots++;/* For each hash entry on this slot... */chainlen =0;he = ht->table[i];while(he){chainlen++;he = he->next;}clvector[(chainlen < DICT_STATS_VECTLEN)? chainlen :(DICT_STATS_VECTLEN-1)]++;if(chainlen > maxchainlen) maxchainlen = chainlen;totchainlen += chainlen;}/* Generate human readable stats. */l +=snprintf(buf+l,bufsize-l,"Hash table %d stats (%s):\n"" table size: %lu\n"" number of elements: %lu\n"" different slots: %lu\n"" max chain length: %lu\n"" avg chain length (counted): %.02f\n"" avg chain length (computed): %.02f\n"" Chain length distribution:\n",tableid,(tableid ==0)?"main hash table":"rehashing target",ht->size, ht->used, slots, maxchainlen,(float)totchainlen/slots,(float)ht->used/slots);for(i =0; i < DICT_STATS_VECTLEN-1; i++){if(clvector[i]==0)continue;if(l >= bufsize)break;l +=snprintf(buf+l,bufsize-l," %s%ld: %ld (%.02f%%)\n",(i == DICT_STATS_VECTLEN-1)?">= ":"",i, clvector[i],((float)clvector[i]/ht->size)*100);}/* Unlike snprintf(), return the number of characters actually written. */if(bufsize) buf[bufsize-1]='\0';returnstrlen(buf);}voiddictGetStats(char*buf,size_t bufsize, dict *d){size_t l;char*orig_buf = buf;size_t orig_bufsize = bufsize;l =_dictGetStatsHt(buf,bufsize,&d->ht[0],0);buf += l;bufsize -= l;if(dictIsRehashing(d)&& bufsize >0){_dictGetStatsHt(buf,bufsize,&d->ht[1],1);}/* Make sure there is a NULL term at the end. */if(orig_bufsize) orig_buf[orig_bufsize-1]='\0';}/* ------------------------------- Benchmark ---------------------------------*/#ifdefREDIS_TESTuint64_thashCallback(constvoid*key){returndictGenHashFunction((unsignedchar*)key,strlen((char*)key));}intcompareCallback(void*privdata,constvoid*key1,constvoid*key2){int l1,l2;DICT_NOTUSED(privdata);l1 =strlen((char*)key1);l2 =strlen((char*)key2);if(l1 != l2)return0;returnmemcmp(key1, key2, l1)==0;}voidfreeCallback(void*privdata,void*val){DICT_NOTUSED(privdata);zfree(val);}char*stringFromLongLong(longlong value){char buf[32];int len;char*s;len =sprintf(buf,"%lld",value);s =zmalloc(len+1);memcpy(s, buf, len);s[len]='\0';return s;}dictType BenchmarkDictType ={hashCallback,NULL,NULL,compareCallback,freeCallback,NULL,NULL};#definestart_benchmark() start =timeInMilliseconds()#defineend_benchmark(msg)do{\elapsed =timeInMilliseconds()-start;\printf(msg ": %ld items in %lld ms\n", count, elapsed);\}while(0)/* ./redis-server test dict [<count> | --accurate] */intdictTest(int argc,char**argv,int accurate){long j;longlong start, elapsed;dict *dict =dictCreate(&BenchmarkDictType,NULL);long count =0;if(argc ==4){if(accurate){count =5000000;}else{count =strtol(argv[3],NULL,10);}}else{count =5000;}start_benchmark();for(j =0; j < count; j++){int retval =dictAdd(dict,stringFromLongLong(j),(void*)j);assert(retval == DICT_OK);}end_benchmark("Inserting");assert((long)dictSize(dict)== count);/* Wait for rehashing. */while(dictIsRehashing(dict)){dictRehashMilliseconds(dict,100);}start_benchmark();for(j =0; j < count; j++){char*key =stringFromLongLong(j);dictEntry *de =dictFind(dict,key);assert(de !=NULL);zfree(key);}end_benchmark("Linear access of existing elements");start_benchmark();for(j =0; j < count; j++){char*key =stringFromLongLong(j);dictEntry *de =dictFind(dict,key);assert(de !=NULL);zfree(key);}end_benchmark("Linear access of existing elements (2nd round)");start_benchmark();for(j =0; j < count; j++){char*key =stringFromLongLong(rand()% count);dictEntry *de =dictFind(dict,key);assert(de !=NULL);zfree(key);}end_benchmark("Random access of existing elements");start_benchmark();for(j =0; j < count; j++){dictEntry *de =dictGetRandomKey(dict);assert(de !=NULL);}end_benchmark("Accessing random keys");start_benchmark();for(j =0; j < count; j++){char*key =stringFromLongLong(rand()% count);key[0]='X';dictEntry *de =dictFind(dict,key);assert(de ==NULL);zfree(key);}end_benchmark("Accessing missing");start_benchmark();for(j =0; j < count; j++){char*key =stringFromLongLong(j);int retval =dictDelete(dict,key);assert(retval == DICT_OK);key[0]+=17;/* Change first number to letter. */retval =dictAdd(dict,key,(void*)j);assert(retval == DICT_OK);}end_benchmark("Removing and adding");dictRelease(dict);return0;}#endif
#include<stdio.h>#include<stdint.h>#include"dict.h"#definesdslenstrlen/* -------------------------- hash functions -------------------------------- *//* Generic hash function (a popular one from Bernstein).* I tested a few and this was the best. */// static unsigned int dictGenHashFunction(const unsigned char *buf, int len) {// unsigned int hash = 5381;// while (len--)// hash = ((hash << 5) + hash) + (*buf++); /* hash * 33 + c */// return hash;// }uint64_tdictSdsHash(constvoid*key){returndictGenHashFunction((unsignedchar*)key,sdslen((char*)key));}intdictSdsKeyCompare(void*privdata,constvoid*key1,constvoid*key2){int l1,l2;DICT_NOTUSED(privdata);// l1 = sdslen((sds)key1);// l2 = sdslen((sds)key2);// if (l1 != l2) return 0;returnmemcmp(key1, key2, l1)==0;}/* Dict type without destructor */
dictType sdsReplyDictType ={dictSdsHash,/* hash function */NULL,/* key dup */NULL,/* val dup */dictSdsKeyCompare,/* key compare */NULL,/* key destructor */NULL,/* val destructor */NULL/* allow to expand */};#defineserverAssert(_e)(_e)?(void)0:(fprintf(stderr,"==> '%s' is not true [%s:%d]\n", #_e,__FILE__,__LINE__))typedefstruct_MapEntry{char*key;char*value;}MapEntry_t;intmain(){int index =0;dict *dictHd =dictCreate(&sdsReplyDictType,NULL);if(NULL== dictHd){printf("NULL == entry\n");return-1;}dictExpand(dictHd,1024);MapEntry_t mapEntry[]={[0]={"key1","1"},[1]={"key2","2"},[2]={"key3","3"},};int numcommands =sizeof(mapEntry)/sizeof(MapEntry_t);printf("numcommands %d \n", numcommands);for(index =0; index < numcommands; index++){printf("add: key: %s, value: %s\n", mapEntry[index].key, mapEntry[index].value);int retVal =dictAdd(dictHd,(void*)mapEntry[index].key,(void*)mapEntry[index].value);serverAssert(retVal == DICT_OK);}dictEntry *find =NULL;find =dictFind(dictHd, mapEntry[0].key);serverAssert(find !=NULL);printf("key %s, value %s\n", mapEntry[0].key, find->v.val);if(find !=NULL)dictReplace(dictHd, mapEntry[0].key,"11");find =dictFind(dictHd, mapEntry[0].key);serverAssert(find !=NULL);if(find !=NULL)printf("key %s, value %s\n", mapEntry[0].key, find->v.val);dictDelete(dictHd, mapEntry[0].key);find =dictFind(dictHd, mapEntry[0].key);serverAssert(find !=NULL);if(find !=NULL)printf("key %s, value %s\n", mapEntry[0].key, find->v.val);find =dictFind(dictHd, mapEntry[2].key);serverAssert(find !=NULL);if(find !=NULL)printf("key %s %s, value %s\n", mapEntry[2].key, find->key,find->v.val);return0;}
被引次数：306 Wang Y, Burgener D, Flores M, et al. Towards {Street-Level}{Client-Independent}{IP} Geolocation[C]//8th USENIX Symposium on Networked Systems Design and Implementation (NSDI 11). 2011. 接着Towards Street-Level Client-Independent IP Geolocati…
