/* 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-Present, Redis Ltd. * All rights reserved. * * Licensed under your choice of (a) the Redis Source Available License 2.0 * (RSALv2); or (b) the Server Side Public License v1 (SSPLv1); or (c) the * GNU Affero General Public License v3 (AGPLv3). */ #include "fmacros.h" #include #include #include #include #include #include #include #include #include "dict.h" #include "zmalloc.h" #include "redisassert.h" #include "monotonic.h" #include "util.h" /* Using dictSetResizeEnabled() 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 DICT_RESIZE_AVOID, not all * resizes are prevented: * - A hash table is still allowed to expand if the ratio between the number * of elements and the buckets >= dict_force_resize_ratio. * - A hash table is still allowed to shrink if the ratio between the number * of elements and the buckets <= 1 / (HASHTABLE_MIN_FILL * dict_force_resize_ratio). */ static dictResizeEnable dict_can_resize = DICT_RESIZE_ENABLE; static unsigned int dict_force_resize_ratio = 4; /* -------------------------- types ----------------------------------------- */ struct dictEntry { struct dictEntry *next; /* Must be first */ void *key; /* Must be second */ union { void *val; uint64_t u64; int64_t s64; double d; } v; }; typedef struct dictEntryNoValue { dictEntry *next; /* Must be first */ void *key; /* Must be second */ } dictEntryNoValue; static_assert(offsetof(dictEntry, next) == offsetof(dictEntryNoValue, next), "dictEntry & dictEntryNoValue next not aligned"); static_assert(offsetof(dictEntry, key) == offsetof(dictEntryNoValue, key), "dictEntry & dictEntryNoValue key not aligned"); /* -------------------------- private prototypes ---------------------------- */ static int _dictExpandIfNeeded(dict *d); static void _dictShrinkIfNeeded(dict *d); static void _dictRehashStepIfNeeded(dict *d, uint64_t visitedIdx); static signed char _dictNextExp(unsigned long size); static int _dictInit(dict *d, dictType *type); static dictEntryLink dictGetNextLink(dictEntry *de); static void dictSetNext(dictEntry *de, dictEntry *next); static int dictDefaultCompare(dictCmpCache *cache, const void *key1, const void *key2); static dictEntryLink dictFindLinkInternal(dict *d, const void *key, dictEntryLink *bucket); dictEntryLink dictFindLinkForInsert(dict *d, const void *key, dictEntry **existing); static dictEntry *dictInsertKeyAtLink(dict *d, void *key __stored_key, dictEntryLink link); /* -------------------------- unused --------------------------- */ void dictSetSignedIntegerVal(dictEntry *de, int64_t val); int64_t dictGetSignedIntegerVal(const dictEntry *de); double dictIncrDoubleVal(dictEntry *de, double val); void *dictEntryMetadata(dictEntry *de); int64_t dictIncrSignedIntegerVal(dictEntry *de, int64_t val); /* -------------------------- misc inline functions -------------------------------- */ typedef int (*keyCmpFunc)(dictCmpCache *cache, const void *key1, const void *key2); static inline keyCmpFunc dictGetCmpFunc(dict *d) { if (d->type->keyCompare) return d->type->keyCompare; return dictDefaultCompare; } static const void *dictStoredKey2Key(dict *d, const void *key __stored_key) { return (d->type->keyFromStoredKey) ? d->type->keyFromStoredKey(key) : key; } /* -------------------------- hash functions -------------------------------- */ static uint8_t dict_hash_function_seed[16]; void dictSetHashFunctionSeed(uint8_t *seed) { memcpy(dict_hash_function_seed,seed,sizeof(dict_hash_function_seed)); } /* The default hashing function uses SipHash implementation * in siphash.c. */ uint64_t siphash(const uint8_t *in, const size_t inlen, const uint8_t *k); uint64_t siphash_nocase(const uint8_t *in, const size_t inlen, const uint8_t *k); uint64_t dictGenHashFunction(const void *key, size_t len) { return siphash(key, len, dict_hash_function_seed); } uint64_t dictGenCaseHashFunction(const unsigned char *buf, size_t len) { return siphash_nocase(buf,len,dict_hash_function_seed); } /* --------------------- dictEntry pointer bit tricks ---------------------- */ /* The 3 least significant bits in a pointer to a dictEntry determines what the * pointer actually points to. If the least bit is set, it's a key. Otherwise, * the bit pattern of the least 3 significant bits mark the kind of entry. */ #define ENTRY_PTR_MASK 7 /* 111 */ #define ENTRY_PTR_NORMAL 0 /* 000 : If a pointer to an entry with value. */ #define ENTRY_PTR_IS_ODD_KEY 1 /* XX1 : If a pointer to odd key address (must be 1). */ #define ENTRY_PTR_IS_EVEN_KEY 2 /* 010 : If a pointer to even key address. (must be 2 or 4). */ #define ENTRY_PTR_UNUSED 4 /* 100 : Unused. */ /* Returns 1 if the entry pointer is a pointer to a key, rather than to an * allocated entry. Returns 0 otherwise. */ static inline int entryIsKey(const dictEntry *de) { return ((uintptr_t)de & (ENTRY_PTR_IS_ODD_KEY | ENTRY_PTR_IS_EVEN_KEY)); } /* Returns 1 if the pointer is actually a pointer to a dictEntry struct. Returns * 0 otherwise. */ static inline int entryIsNormal(const dictEntry *de) { return ((uintptr_t)(void *)de & ENTRY_PTR_MASK) == ENTRY_PTR_NORMAL; } /* Creates an entry without a value field. */ static inline dictEntry *createEntryNoValue(void *key __stored_key, dictEntry *next) { dictEntryNoValue *entry = zmalloc(sizeof(*entry)); entry->key = key; entry->next = next; return (dictEntry *) entry; } static inline dictEntry *encodeMaskedPtr(const void *ptr, unsigned int bits) { assert(((uintptr_t)ptr & ENTRY_PTR_MASK) == 0); return (dictEntry *)(void *)((uintptr_t)ptr | bits); } static inline void *decodeMaskedPtr(const dictEntry *de) { return (void *)((uintptr_t)(void *)de & ~ENTRY_PTR_MASK); } /* Encode a key pointer for storage in a no_value dict bucket. * For odd keys (like SDS strings), the key can be stored directly. * For even keys, we need to tag it with ENTRY_PTR_IS_EVEN_KEY. */ static inline dictEntry *encodeEntryKey(dict *d, void *key) { if (d->type->keys_are_odd) { debugAssert(((uintptr_t)key & ENTRY_PTR_IS_ODD_KEY) == ENTRY_PTR_IS_ODD_KEY); return key; } else { return encodeMaskedPtr(key, ENTRY_PTR_IS_EVEN_KEY); } } /* Decodes the pointer to an entry without value, when you know it is an entry * without value. Hint: Use entryIsNoValue to check. */ static inline dictEntryNoValue *decodeEntryNoValue(const dictEntry *de) { return decodeMaskedPtr(de); } /* Returns 1 if the entry has a value field and 0 otherwise. */ static inline int entryHasValue(const dictEntry *de) { return entryIsNormal(de); } /* ----------------------------- API implementation ------------------------- */ /* Reset hash table parameters already initialized with _dictInit()*/ static void _dictReset(dict *d, int htidx) { d->ht_table[htidx] = NULL; d->ht_size_exp[htidx] = -1; d->ht_used[htidx] = 0; } /* Create a new hash table */ dict *dictCreate(dictType *type) { size_t metasize = type->dictMetadataBytes ? type->dictMetadataBytes(NULL) : 0; dict *d = zmalloc(sizeof(*d)+metasize); if (metasize > 0) { memset(dictMetadata(d), 0, metasize); } _dictInit(d,type); return d; } /* Change dictType of dict to another one with metadata support * Rest of dictType's values must stay the same */ void dictTypeAddMeta(dict **d, dictType *typeWithMeta) { /* Verify new dictType is compatible with the old one */ dictType toCmp = *typeWithMeta; /* Ignore 'dictMetadataBytes' and 'onDictRelease' in comparison */ toCmp.dictMetadataBytes = (*d)->type->dictMetadataBytes; toCmp.onDictRelease = (*d)->type->onDictRelease; assert(memcmp((*d)->type, &toCmp, sizeof(dictType)) == 0); /* The rest of the dictType fields must be the same */ *d = zrealloc(*d, sizeof(dict) + typeWithMeta->dictMetadataBytes(*d)); (*d)->type = typeWithMeta; } /* Initialize the hash table */ int _dictInit(dict *d, dictType *type) { _dictReset(d, 0); _dictReset(d, 1); d->type = type; d->rehashidx = -1; d->pauserehash = 0; d->pauseAutoResize = 0; return DICT_OK; } /* Resize 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 resize was performed, and DICT_ERR if skipped. */ int _dictResize(dict *d, unsigned long size, int* malloc_failed) { if (malloc_failed) *malloc_failed = 0; /* We can't rehash twice if rehashing is ongoing. */ assert(!dictIsRehashing(d)); /* the new hash table */ dictEntry **new_ht_table; unsigned long new_ht_used; signed char new_ht_size_exp = _dictNextExp(size); /* Detect overflows */ size_t newsize = DICTHT_SIZE(new_ht_size_exp); if (newsize < size || newsize * sizeof(dictEntry*) < newsize) return DICT_ERR; /* Rehashing to the same table size is not useful. */ if (new_ht_size_exp == d->ht_size_exp[0]) return DICT_ERR; /* Allocate the new hash table and initialize all pointers to NULL */ if (malloc_failed) { new_ht_table = ztrycalloc(newsize*sizeof(dictEntry*)); *malloc_failed = new_ht_table == NULL; if (*malloc_failed) return DICT_ERR; } else new_ht_table = zcalloc(newsize*sizeof(dictEntry*)); new_ht_used = 0; /* Prepare a second hash table for incremental rehashing. * We do this even for the first initialization, so that we can trigger the * rehashingStarted more conveniently, we will clean it up right after. */ d->ht_size_exp[1] = new_ht_size_exp; d->ht_used[1] = new_ht_used; d->ht_table[1] = new_ht_table; d->rehashidx = 0; if (d->type->rehashingStarted) d->type->rehashingStarted(d); if (d->type->bucketChanged) d->type->bucketChanged(d, DICTHT_SIZE(d->ht_size_exp[1])); /* Is this the first initialization or is the first hash table empty? If so * it's not really a rehashing, we can just set the first hash table so that * it can accept keys. */ if (d->ht_table[0] == NULL || d->ht_used[0] == 0) { if (d->type->rehashingCompleted) d->type->rehashingCompleted(d); if (d->type->bucketChanged) d->type->bucketChanged(d, -(long long)DICTHT_SIZE(d->ht_size_exp[0])); if (d->ht_table[0]) zfree(d->ht_table[0]); d->ht_size_exp[0] = new_ht_size_exp; d->ht_used[0] = new_ht_used; d->ht_table[0] = new_ht_table; _dictReset(d, 1); d->rehashidx = -1; return DICT_OK; } /* Force a full rehashing of the dictionary */ if (d->type->force_full_rehash) { while (dictRehash(d, 1000)) { /* Continue rehashing */ } } return DICT_OK; } int _dictExpand(dict *d, unsigned long size, int* malloc_failed) { /* the size is invalid if it is smaller than the size of the hash table * or smaller than the number of elements already inside the hash table */ if (dictIsRehashing(d) || d->ht_used[0] > size || DICTHT_SIZE(d->ht_size_exp[0]) >= size) return DICT_ERR; return _dictResize(d, size, malloc_failed); } /* return DICT_ERR if expand was not performed */ int dictExpand(dict *d, unsigned long size) { return _dictExpand(d, size, NULL); } /* return DICT_ERR if expand failed due to memory allocation failure */ int dictTryExpand(dict *d, unsigned long size) { int malloc_failed = 0; _dictExpand(d, size, &malloc_failed); return malloc_failed? DICT_ERR : DICT_OK; } /* return DICT_ERR if shrink was not performed */ int dictShrink(dict *d, unsigned long size) { /* the size is invalid if it is bigger than the size of the hash table * or smaller than the number of elements already inside the hash table */ if (dictIsRehashing(d) || d->ht_used[0] > size || DICTHT_SIZE(d->ht_size_exp[0]) <= size) return DICT_ERR; return _dictResize(d, size, NULL); } /* Helper function for `dictRehash` and `dictBucketRehash` which rehashes all the keys * in a bucket at index `idx` from the old to the new hash HT. */ static void rehashEntriesInBucketAtIndex(dict *d, uint64_t idx) { dictEntry *de = d->ht_table[0][idx]; uint64_t h; dictEntry *nextde; while (de) { nextde = dictGetNext(de); void *storedKey = dictGetKey(de); /* Get the index in the new hash table */ if (d->ht_size_exp[1] > d->ht_size_exp[0]) { const void *key = dictStoredKey2Key(d, storedKey); h = dictGetHash(d, key) & DICTHT_SIZE_MASK(d->ht_size_exp[1]); } else { /* We're shrinking the table. The tables sizes are powers of * two, so we simply mask the bucket index in the larger table * to get the bucket index in the smaller table. */ h = idx & DICTHT_SIZE_MASK(d->ht_size_exp[1]); } if (d->type->no_value) { if (!d->ht_table[1][h]) { /* The destination bucket is empty, allowing the key to be stored * directly without allocating a dictEntry. If an old entry was * previously allocated, free its memory. */ if (!entryIsKey(de)) zfree(decodeMaskedPtr(de)); de = encodeEntryKey(d, storedKey); } else if (entryIsKey(de)) { /* We don't have an allocated entry but we need one. */ de = createEntryNoValue(storedKey, d->ht_table[1][h]); } else { dictSetNext(de, d->ht_table[1][h]); } } else { dictSetNext(de, d->ht_table[1][h]); } d->ht_table[1][h] = de; d->ht_used[0]--; d->ht_used[1]++; de = nextde; } d->ht_table[0][idx] = NULL; } /* This checks if we already rehashed the whole table and if more rehashing is required */ static int dictCheckRehashingCompleted(dict *d) { if (d->ht_used[0] != 0) return 0; if (d->type->rehashingCompleted) d->type->rehashingCompleted(d); if (d->type->bucketChanged) d->type->bucketChanged(d, -(long long)DICTHT_SIZE(d->ht_size_exp[0])); zfree(d->ht_table[0]); /* Copy the new ht onto the old one */ d->ht_table[0] = d->ht_table[1]; d->ht_used[0] = d->ht_used[1]; d->ht_size_exp[0] = d->ht_size_exp[1]; _dictReset(d, 1); d->rehashidx = -1; return 1; } /* 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. */ int dictRehash(dict *d, int n) { int empty_visits = n*10; /* Max number of empty buckets to visit. */ unsigned long s0 = DICTHT_SIZE(d->ht_size_exp[0]); unsigned long s1 = DICTHT_SIZE(d->ht_size_exp[1]); if (dict_can_resize == DICT_RESIZE_FORBID || !dictIsRehashing(d)) return 0; /* If dict_can_resize is DICT_RESIZE_AVOID, we want to avoid rehashing. * - If expanding, the threshold is dict_force_resize_ratio which is 4. * - If shrinking, the threshold is 1 / (HASHTABLE_MIN_FILL * dict_force_resize_ratio) which is 1/32. */ if (dict_can_resize == DICT_RESIZE_AVOID && ((s1 > s0 && s1 < dict_force_resize_ratio * s0) || (s1 < s0 && s0 < HASHTABLE_MIN_FILL * dict_force_resize_ratio * s1))) { return 0; } while(n-- && d->ht_used[0] != 0) { /* Note that rehashidx can't overflow as we are sure there are more * elements because ht[0].used != 0 */ assert(DICTHT_SIZE(d->ht_size_exp[0]) > (unsigned long)d->rehashidx); while(d->ht_table[0][d->rehashidx] == NULL) { d->rehashidx++; if (--empty_visits == 0) return 1; } /* Move all the keys in this bucket from the old to the new hash HT */ rehashEntriesInBucketAtIndex(d, d->rehashidx); d->rehashidx++; } return !dictCheckRehashingCompleted(d); } long long timeInMilliseconds(void) { struct timeval tv; gettimeofday(&tv,NULL); return (((long long)tv.tv_sec)*1000)+(tv.tv_usec/1000); } /* Rehash in us+"delta" microseconds. The value of "delta" is larger * than 0, and is smaller than 1000 in most cases. The exact upper bound * depends on the running time of dictRehash(d,100).*/ int dictRehashMicroseconds(dict *d, uint64_t us) { if (d->pauserehash > 0) return 0; monotime timer; elapsedStart(&timer); int rehashes = 0; while(dictRehash(d,100)) { rehashes += 100; if (elapsedUs(timer) >= us) 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 elements 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. */ static void _dictRehashStep(dict *d) { if (d->pauserehash == 0) dictRehash(d,1); } /* Performs rehashing on a single bucket. */ int _dictBucketRehash(dict *d, uint64_t idx) { if (d->pauserehash != 0) return 0; unsigned long s0 = DICTHT_SIZE(d->ht_size_exp[0]); unsigned long s1 = DICTHT_SIZE(d->ht_size_exp[1]); if (dict_can_resize == DICT_RESIZE_FORBID || !dictIsRehashing(d)) return 0; /* If dict_can_resize is DICT_RESIZE_AVOID, we want to avoid rehashing. * - If expanding, the threshold is dict_force_resize_ratio which is 4. * - If shrinking, the threshold is 1 / (HASHTABLE_MIN_FILL * dict_force_resize_ratio) which is 1/32. */ if (dict_can_resize == DICT_RESIZE_AVOID && ((s1 > s0 && s1 < dict_force_resize_ratio * s0) || (s1 < s0 && s0 < HASHTABLE_MIN_FILL * dict_force_resize_ratio * s1))) { return 0; } rehashEntriesInBucketAtIndex(d, idx); dictCheckRehashingCompleted(d); return 1; } /* Add an element to the target hash table */ int dictAdd(dict *d, void *key __stored_key, void *val) { dictEntry *entry = dictAddRaw(d,key,NULL); if (!entry) return DICT_ERR; if (!d->type->no_value) dictSetVal(d, entry, val); return DICT_OK; } int dictCompareKeys(dict *d, const void *key1, const void *key2) { dictCmpCache cache = {0}; keyCmpFunc cmpFunc = dictGetCmpFunc(d); return cmpFunc(&cache, key1, key2); } /* 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 __stored_key, dictEntry **existing) { /* Get the position for the new key or NULL if the key already exists. */ void *position = dictFindLinkForInsert(d, dictStoredKey2Key(d, key), existing); if (!position) return NULL; /* Dup the key if necessary. */ if (d->type->keyDup) key = d->type->keyDup(d, key); return dictInsertKeyAtLink(d, key, position); } /* Adds a key in the dict's hashtable at the link returned by a preceding * call to dictFindLinkForInsert(). This is a low level function which allows * splitting dictAddRaw in two parts. Normally, dictAddRaw or dictAdd should be * used instead. It assumes that dictExpandIfNeeded() was called before. */ dictEntry *dictInsertKeyAtLink(dict *d, void *key __stored_key, dictEntryLink link) { dictEntryLink bucket = link; /* It's a bucket, but the API hides that. */ dictEntry *entry; /* If rehashing is ongoing, we insert in table 1, otherwise in table 0. * Assert that the provided bucket is the right table. */ int htidx = dictIsRehashing(d) ? 1 : 0; assert(bucket >= &d->ht_table[htidx][0] && bucket <= &d->ht_table[htidx][DICTHT_SIZE_MASK(d->ht_size_exp[htidx])]); if (d->type->no_value) { if (!*bucket) { /* We can store the key directly in the destination bucket without * allocating dictEntry. */ entry = encodeEntryKey(d, key); assert(entryIsKey(entry)); } else { /* Allocate an entry without value. */ entry = createEntryNoValue(key, *bucket); } } else { /* 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. */ entry = zmalloc(sizeof(*entry)); assert(entryIsNormal(entry)); /* Check alignment of allocation */ entry->key = key; entry->next = *bucket; } *bucket = entry; d->ht_used[htidx]++; 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. */ int dictReplace(dict *d, void *key __stored_key, void *val) { dictEntry *entry, *existing; /* 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); return 1; } /* 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. */ void *oldval = dictGetVal(existing); dictSetVal(d, existing, val); if (d->type->valDestructor) d->type->valDestructor(d, oldval); return 0; } /* 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 __stored_key) { dictEntry *entry, *existing; entry = dictAddRaw(d,key,&existing); return entry ? entry : existing; } /* Search and remove an element. This is a helper function for * dictDelete() and dictUnlink(), please check the top comment * of those functions. */ static dictEntry *dictGenericDelete(dict *d, const void *key, int nofree) { dictCmpCache cmpCache = {0}; uint64_t h, idx; dictEntry *he, *prevHe; int table; /* dict is empty */ if (dictSize(d) == 0) return NULL; h = dictGetHash(d, key); idx = h & DICTHT_SIZE_MASK(d->ht_size_exp[0]); /* Rehash the hash table if needed */ _dictRehashStepIfNeeded(d,idx); keyCmpFunc cmpFunc = dictGetCmpFunc(d); for (table = 0; table <= 1; table++) { if (table == 0 && (long)idx < d->rehashidx) continue; idx = h & DICTHT_SIZE_MASK(d->ht_size_exp[table]); he = d->ht_table[table][idx]; prevHe = NULL; while(he) { const void *he_key = dictStoredKey2Key(d, dictGetKey(he)); if (key == he_key || cmpFunc(&cmpCache, key, he_key)) { /* Unlink the element from the list */ if (prevHe) dictSetNext(prevHe, dictGetNext(he)); else d->ht_table[table][idx] = dictGetNext(he); if (!nofree) { dictFreeUnlinkedEntry(d, he); } d->ht_used[table]--; _dictShrinkIfNeeded(d); return he; } prevHe = he; he = dictGetNext(he); } if (!dictIsRehashing(d)) break; } return NULL; /* not found */ } /* Remove an element, returning DICT_OK on success or DICT_ERR if the * element was not found. */ int dictDelete(dict *ht, const void *key) { return dictGenericDelete(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 *d, const void *key) { return dictGenericDelete(d,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. */ void dictFreeUnlinkedEntry(dict *d, dictEntry *he) { if (he == NULL) return; dictFreeKey(d, he); dictFreeVal(d, he); if (!entryIsKey(he)) zfree(decodeMaskedPtr(he)); } /* Destroy an entire dictionary */ int _dictClear(dict *d, int htidx, void(callback)(dict*)) { unsigned long i; /* Free all the elements */ for (i = 0; i < DICTHT_SIZE(d->ht_size_exp[htidx]) && d->ht_used[htidx] > 0; i++) { dictEntry *he, *nextHe; /* Callback will be called once for every 65535 deletions. Beware, * if dict has less than 65535 items, it will not be called at all.*/ if (callback && i != 0 && (i & 65535) == 0) callback(d); if ((he = d->ht_table[htidx][i]) == NULL) continue; while(he) { nextHe = dictGetNext(he); dictFreeKey(d, he); dictFreeVal(d, he); if (!entryIsKey(he)) zfree(decodeMaskedPtr(he)); d->ht_used[htidx]--; he = nextHe; } } /* Free the table and the allocated cache structure */ zfree(d->ht_table[htidx]); /* Re-initialize the table */ _dictReset(d, htidx); return DICT_OK; /* never fails */ } /* Clear & Release the hash table */ void dictRelease(dict *d) { /* Someone may be monitoring a dict that started rehashing, before * destroying the dict fake completion. */ if (dictIsRehashing(d) && d->type->rehashingCompleted) d->type->rehashingCompleted(d); /* Subtract the size of all buckets. */ if (d->type->bucketChanged) d->type->bucketChanged(d, -(long long)dictBuckets(d)); if (d->type->onDictRelease) d->type->onDictRelease(d); _dictClear(d,0,NULL); _dictClear(d,1,NULL); zfree(d); } /* Finds a given key. Like dictFindLink(), yet search bucket even if dict is empty. * * Returns dictEntryLink reference if found. Otherwise, return NULL. * * bucket - return pointer to bucket that the key was mapped. unless dict is empty. */ static dictEntryLink dictFindLinkInternal(dict *d, const void *key, dictEntryLink *bucket) { dictCmpCache cmpCache = {0}; dictEntryLink link; uint64_t idx; int table; if (bucket) { *bucket = NULL; } else { /* If dict is empty and no need to find bucket, return NULL */ if (dictSize(d) == 0) return NULL; } const uint64_t hash = dictGetHash(d, key); idx = hash & DICTHT_SIZE_MASK(d->ht_size_exp[0]); keyCmpFunc cmpFunc = dictGetCmpFunc(d); /* Rehash the hash table if needed */ _dictRehashStepIfNeeded(d,idx); int tables = (dictIsRehashing(d)) ? 2 : 1; for (table = 0; table < tables; table++) { if (table == 0 && (long)idx < d->rehashidx) continue; idx = hash & DICTHT_SIZE_MASK(d->ht_size_exp[table]); link = &(d->ht_table[table][idx]); if (bucket) *bucket = link; while(link && *link) { const void *visitedKey = dictStoredKey2Key(d, dictGetKey(*link)); if (key == visitedKey || cmpFunc( &cmpCache, key, visitedKey)) return link; link = dictGetNextLink(*link); } } return NULL; } dictEntry *dictFind(dict *d, const void *key) { dictEntryLink link = dictFindLink(d, key, NULL); return (link) ? *link : NULL; } /* Finds the dictEntry 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 a pointer to the dictEntry if found, or NULL if not found. */ dictEntry *dictFindByHashAndPtr(dict *d, const void *oldptr, const uint64_t hash) { dictEntry *he; unsigned long idx, table; if (dictSize(d) == 0) return NULL; /* dict is empty */ for (table = 0; table <= 1; table++) { idx = hash & DICTHT_SIZE_MASK(d->ht_size_exp[table]); if (table == 0 && (long)idx < d->rehashidx) continue; he = d->ht_table[table][idx]; while(he) { if (oldptr == dictGetKey(he)) return he; he = dictGetNext(he); } if (!dictIsRehashing(d)) return NULL; } return NULL; } /* Find a key and return its dictEntryLink reference. Otherwise, return NULL * * A dictEntryLink pointer being used to find preceding dictEntry of searched item. * It is Useful for deletion, addition, unlinking and updating, especially for * dict configured with 'no_value'. In such cases returning only `dictEntry` from * a lookup may be insufficient since it might be opt-out to be the object itself. * By locating preceding dictEntry (dictEntryLink) these ops can be properly handled. * * After calling link = dictFindLink(...), any necessary updates based on returned * link or bucket must be performed immediately after by calling dictSetKeyAtLink() * without any intervening operations on given dict. Otherwise, `dictEntryLink` may * become invalid. Example with kvobj of replacing key with new key: * * link = dictFindLink(d, key, &bucket, 0); * ... Do something, but don't modify the dict ... * // assert(link != NULL); * dictSetKeyAtLink(d, kv, &link, 0); * * To add new value (If no space for the new key, dict will be expanded by * dictSetKeyAtLink() and bucket will be looked up again.): * * link = dictFindLink(d, key, &bucket); * ... Do something, but don't modify the dict ... * // assert(link == NULL); * dictSetKeyAtLink(d, kv, &bucket, 1); * * bucket - return link to bucket that the key was mapped. unless dict is empty. */ dictEntryLink dictFindLink(dict *d, const void *key, dictEntryLink *bucket) { if (bucket) *bucket = NULL; if (unlikely(dictSize(d) == 0)) return NULL; return dictFindLinkInternal(d, key, bucket); } /* Set the key with link * * link: - When `newItem` is set, `link` points to the bucket of the key. * - When `newItem` is not set, `link` points to the link of the key. * - If *link is NULL, dictFindLink() will be called to locate the key. * - On return, get updated, by need, to the inserted key. * * newItem: 1 = Add a key with a new dictEntry. * 0 = Set a key to an existing dictEntry. */ void dictSetKeyAtLink(dict *d, void *key __stored_key, dictEntryLink *link, int newItem) { dictEntryLink dummy = NULL; if (link == NULL) link = &dummy; void *addedKey = (d->type->keyDup) ? d->type->keyDup(d, key) : key; if (newItem) { signed char snap[2] = {d->ht_size_exp[0], d->ht_size_exp[1] }; /* Make room if needed for the new key */ dictExpandIfNeeded(d); /* Lookup key's link if tables reallocated or if given link is set to NULL */ if (snap[0] != d->ht_size_exp[0] || snap[1] != d->ht_size_exp[1] || *link == NULL) { dictEntryLink bucket; /* Bypass dictFindLink() to search bucket even if dict is empty!!! */ *link = dictFindLinkInternal(d, dictStoredKey2Key(d, key), &bucket); assert(bucket != NULL); assert(*link == NULL); *link = bucket; /* On newItem the link should be the bucket */ } dictInsertKeyAtLink(d, addedKey, *link); return; } /* Setting key of existing dictEntry (newItem == 0)*/ if (*link == NULL) { *link = dictFindLink(d, key, NULL); assert(*link != NULL); } dictEntry **de = *link; if (entryIsKey(*de)) { /* `de` opt-out to be actually a key. Replace key but keep the lsb flags */ *de = encodeEntryKey(d, addedKey); } else { /* either dictEntry or dictEntryNoValue */ (*de)->key = addedKey; } } void *dictFetchValue(dict *d, const void *key) { dictEntry *he; he = dictFind(d,key); return he ? dictGetVal(he) : NULL; } /* Find an element from the table. A link is returned if the element is found, and * the user should later call `dictTwoPhaseUnlinkFree` with it in order to unlink * and release it. Otherwise if the key is not found, NULL is returned. These two * functions should be used in pair. * `dictTwoPhaseUnlinkFind` pauses rehash and `dictTwoPhaseUnlinkFree` resumes rehash. * * We can use like this: * * dictEntryLink link = dictTwoPhaseUnlinkFind(db->dict,key->ptr, &table); * // Do something, but we can't modify the dict * dictTwoPhaseUnlinkFree(db->dict, link, table); // We don't need to lookup again * * If we want to find an entry before delete this entry, this an optimization to avoid * dictFind followed by dictDelete. i.e. the first API is a find, and it gives some info * to the second one to avoid repeating the lookup */ dictEntryLink dictTwoPhaseUnlinkFind(dict *d, const void *key, int *table_index) { dictCmpCache cmpCache = {0}; uint64_t h, idx, table; if (dictSize(d) == 0) return NULL; /* dict is empty */ if (dictIsRehashing(d)) _dictRehashStep(d); h = dictGetHash(d, key); keyCmpFunc cmpFunc = dictGetCmpFunc(d); for (table = 0; table <= 1; table++) { idx = h & DICTHT_SIZE_MASK(d->ht_size_exp[table]); if (table == 0 && (long)idx < d->rehashidx) continue; dictEntry **ref = &d->ht_table[table][idx]; while (ref && *ref) { const void *de_key = dictStoredKey2Key(d, dictGetKey(*ref)); if (key == de_key || cmpFunc(&cmpCache, key, de_key)) { *table_index = table; dictPauseRehashing(d); return ref; } ref = dictGetNextLink(*ref); } if (!dictIsRehashing(d)) return NULL; } return NULL; } void dictTwoPhaseUnlinkFree(dict *d, dictEntryLink plink, int table_index) { if (plink == NULL || *plink == NULL) return; dictEntry *de = *plink; d->ht_used[table_index]--; *plink = dictGetNext(de); dictFreeKey(d, de); dictFreeVal(d, de); if (!entryIsKey(de)) zfree(decodeMaskedPtr(de)); _dictShrinkIfNeeded(d); dictResumeRehashing(d); } void dictSetKey(dict *d, dictEntry* de, void *key __stored_key) { assert(!d->type->no_value); if (d->type->keyDup) de->key = d->type->keyDup(d, key); else de->key = key; } void dictSetVal(dict *d, dictEntry *de, void *val) { assert(entryHasValue(de)); de->v.val = d->type->valDup ? d->type->valDup(d, val) : val; } void dictSetSignedIntegerVal(dictEntry *de, int64_t val) { assert(entryHasValue(de)); de->v.s64 = val; } void dictSetUnsignedIntegerVal(dictEntry *de, uint64_t val) { assert(entryHasValue(de)); de->v.u64 = val; } void dictSetDoubleVal(dictEntry *de, double val) { assert(entryHasValue(de)); de->v.d = val; } int64_t dictIncrSignedIntegerVal(dictEntry *de, int64_t val) { assert(entryHasValue(de)); return de->v.s64 += val; } uint64_t dictIncrUnsignedIntegerVal(dictEntry *de, uint64_t val) { assert(entryHasValue(de)); return de->v.u64 += val; } double dictIncrDoubleVal(dictEntry *de, double val) { assert(entryHasValue(de)); return de->v.d += val; } int dictEntryIsKey(const dictEntry *de) { return entryIsKey(de); } void *dictGetKey(const dictEntry *de) { /* if entryIsKey() */ if ((uintptr_t)de & ENTRY_PTR_IS_ODD_KEY) return (void *) de; if ((uintptr_t)de & ENTRY_PTR_IS_EVEN_KEY) return decodeMaskedPtr(de); /* Regular entry */ return de->key; } void *dictGetVal(const dictEntry *de) { assert(entryHasValue(de)); return de->v.val; } int64_t dictGetSignedIntegerVal(const dictEntry *de) { assert(entryHasValue(de)); return de->v.s64; } uint64_t dictGetUnsignedIntegerVal(const dictEntry *de) { assert(entryHasValue(de)); return de->v.u64; } double dictGetDoubleVal(const dictEntry *de) { assert(entryHasValue(de)); return de->v.d; } /* Returns a mutable reference to the value as a double within the entry. */ double *dictGetDoubleValPtr(dictEntry *de) { assert(entryHasValue(de)); return &de->v.d; } /* Returns the 'next' field of the entry or NULL if the entry doesn't have a * 'next' field. */ dictEntry *dictGetNext(const dictEntry *de) { if (entryIsKey(de)) return NULL; /* there's no next */ /* Must come after entryIsKey() check */ return de->next; } /* Returns a pointer to the 'next' field in the entry or NULL if the entry * doesn't have a next field. */ static dictEntryLink dictGetNextLink(dictEntry *de) { if (entryIsKey(de)) return NULL; /* Must come after entryIsKey() check */ return &de->next; } static void dictSetNext(dictEntry *de, dictEntry *next) { assert(!entryIsKey(de)); /* dictEntryNoValue & dictEntry are layout-compatible */ de->next = next; } /* Returns the memory usage in bytes of the dict, excluding the size of the keys * and values. */ size_t dictMemUsage(const dict *d) { return dictSize(d) * sizeof(dictEntry) + dictBuckets(d) * sizeof(dictEntry*); } size_t dictEntryMemUsage(int noValueDict) { return (noValueDict) ? sizeof(dictEntryNoValue) :sizeof(dictEntry); } /* 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. */ unsigned long long dictFingerprint(dict *d) { unsigned long long integers[6], hash = 0; int j; integers[0] = (long) d->ht_table[0]; integers[1] = d->ht_size_exp[0]; integers[2] = d->ht_used[0]; integers[3] = (long) d->ht_table[1]; integers[4] = d->ht_size_exp[1]; integers[5] = d->ht_used[1]; /* 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 * 265 hash = hash ^ (hash >> 14); hash = (hash + (hash << 2)) + (hash << 4); // hash * 21 hash = hash ^ (hash >> 28); hash = hash + (hash << 31); } return hash; } void dictInitIterator(dictIterator *iter, dict *d) { iter->d = d; iter->table = 0; iter->index = -1; iter->safe = 0; iter->entry = NULL; iter->nextEntry = NULL; } void dictInitSafeIterator(dictIterator *iter, dict *d) { dictInitIterator(iter, d); iter->safe = 1; } void dictResetIterator(dictIterator *iter) { if (!(iter->index == -1 && iter->table == 0)) { if (iter->safe) dictResumeRehashing(iter->d); else assert(iter->fingerprint == dictFingerprint(iter->d)); } } dictIterator *dictGetIterator(dict *d) { dictIterator *iter = zmalloc(sizeof(*iter)); dictInitIterator(iter, d); 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) { if (iter->index == -1 && iter->table == 0) { if (iter->safe) dictPauseRehashing(iter->d); else iter->fingerprint = dictFingerprint(iter->d); /* skip the rehashed slots in table[0] */ if (dictIsRehashing(iter->d)) { iter->index = iter->d->rehashidx - 1; } } iter->index++; if (iter->index >= (long) DICTHT_SIZE(iter->d->ht_size_exp[iter->table])) { if (dictIsRehashing(iter->d) && iter->table == 0) { iter->table++; iter->index = 0; } else { break; } } iter->entry = iter->d->ht_table[iter->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 = dictGetNext(iter->entry); return iter->entry; } } return NULL; } void dictReleaseIterator(dictIterator *iter) { dictResetIterator(iter); zfree(iter); } /* Return a random entry from the hash table. Useful to * implement randomized algorithms */ dictEntry *dictGetRandomKey(dict *d) { dictEntry *he, *orighe; unsigned long h; int listlen, listele; if (dictSize(d) == 0) return NULL; if (dictIsRehashing(d)) _dictRehashStep(d); if (dictIsRehashing(d)) { unsigned long s0 = DICTHT_SIZE(d->ht_size_exp[0]); do { /* We are sure there are no elements in indexes from 0 * to rehashidx-1 */ h = d->rehashidx + (randomULong() % (dictBuckets(d) - d->rehashidx)); he = (h >= s0) ? d->ht_table[1][h - s0] : d->ht_table[0][h]; } while(he == NULL); } else { unsigned long m = DICTHT_SIZE_MASK(d->ht_size_exp[0]); do { h = randomULong() & m; he = d->ht_table[0][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 = dictGetNext(he); listlen++; } listele = random() % listlen; he = orighe; while(listele--) he = dictGetNext(he); 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. */ unsigned int dictGetSomeKeys(dict *d, dictEntry **des, unsigned int count) { unsigned long j; /* internal hash table id, 0 or 1. */ unsigned long tables; /* 1 or 2 tables? */ unsigned long stored = 0, maxsizemask; unsigned long 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); else break; } tables = dictIsRehashing(d) ? 2 : 1; maxsizemask = DICTHT_SIZE_MASK(d->ht_size_exp[0]); if (tables > 1 && maxsizemask < DICTHT_SIZE_MASK(d->ht_size_exp[1])) maxsizemask = DICTHT_SIZE_MASK(d->ht_size_exp[1]); /* Pick a random point inside the larger table. */ unsigned long i = randomULong() & maxsizemask; unsigned long 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 < (unsigned long) 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 >= DICTHT_SIZE(d->ht_size_exp[1])) i = d->rehashidx; else continue; } if (i >= DICTHT_SIZE(d->ht_size_exp[j])) continue; /* Out of range for this table. */ dictEntry *he = d->ht_table[j][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. * To avoid the issue of being unable to sample the end of a long chain, * we utilize the Reservoir Sampling algorithm to optimize the sampling process. * This means that even when the maximum number of samples has been reached, * we continue sampling until we reach the end of the chain. * See https://en.wikipedia.org/wiki/Reservoir_sampling. */ if (stored < count) { des[stored] = he; } else { unsigned long r = randomULong() % (stored + 1); if (r < count) des[r] = he; } he = dictGetNext(he); stored++; } if (stored >= count) goto end; } } i = (i+1) & maxsizemask; } end: return stored > count ? count : stored; } /* Reallocate the dictEntry, key and value allocations in a bucket using the * provided allocation functions in order to defrag them. */ static void dictDefragBucket(dict *d, dictEntry **bucketref, dictDefragFunctions *defragfns) { dictDefragAllocFunction *defragalloc = defragfns->defragAlloc; dictDefragAllocFunction *defragkey = defragfns->defragKey; dictDefragAllocFunction *defragval = defragfns->defragVal; while (bucketref && *bucketref) { dictEntry *de = *bucketref, *newde = NULL; void *newkey = defragkey ? defragkey(dictGetKey(de)) : NULL; if (d->type->no_value) { if (entryIsKey(de)) { if (newkey) *bucketref = encodeEntryKey(d, newkey); } else { dictEntryNoValue *entry = decodeEntryNoValue(de), *newentry; if ((newentry = defragalloc(entry))) { newde = (dictEntry *) newentry; entry = newentry; } if (newkey) entry->key = newkey; } } else { void *newval = defragval ? defragval(dictGetVal(de)) : NULL; assert(entryIsNormal(de)); newde = defragalloc(de); if (newde) de = newde; if (newkey) de->key = newkey; if (newval) de->v.val = newval; } if (newde) { *bucketref = newde; } bucketref = dictGetNextLink(*bucketref); } } /* 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. */ #define GETFAIR_NUM_ENTRIES 15 dictEntry *dictGetFairRandomKey(dict *d) { dictEntry *entries[GETFAIR_NUM_ENTRIES]; unsigned int 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) return dictGetRandomKey(d); unsigned int idx = rand() % count; return entries[idx]; } /* Function to reverse bits. Algorithm from: * http://graphics.stanford.edu/~seander/bithacks.html#ReverseParallel */ static unsigned long rev(unsigned long v) { unsigned long s = CHAR_BIT * sizeof(v); // bit size; must be power of 2 unsigned long 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. */ unsigned long dictScan(dict *d, unsigned long v, dictScanFunction *fn, void *privdata) { return dictScanDefrag(d, v, fn, NULL, privdata); } void dictScanDefragBucket(dict *d,dictScanFunction *fn, dictDefragFunctions *defragfns, void *privdata, dictEntry **bucketref) { dictEntry **plink, *de, *next; /* Emit entries at bucket */ if (defragfns) dictDefragBucket(d, bucketref, defragfns); de = *bucketref; plink = bucketref; while (de) { next = dictGetNext(de); fn(privdata, de, plink); if (!next) break; /* if last element, break */ /* if `*plink` still pointing to 'de', then it means that the * visited item wasn't deleted by fn() */ if (*plink == de) plink = &(de->next); de = next; } } /* Like dictScan, but additionally reallocates the memory used by the dict * entries using the provided allocation function. This feature was added for * the active defrag feature. * * The 'defragfns' callbacks are called with a pointer to memory that callback * can reallocate. The callbacks should return a new memory address or NULL, * where NULL means that no reallocation happened and the old memory is still * valid. */ unsigned long dictScanDefrag(dict *d, unsigned long v, dictScanFunction *fn, dictDefragFunctions *defragfns, void *privdata) { int htidx0, htidx1; unsigned long m0, m1; if (dictSize(d) == 0) return 0; /* This is needed in case the scan callback tries to do dictFind or alike. */ dictPauseRehashing(d); if (!dictIsRehashing(d)) { htidx0 = 0; m0 = DICTHT_SIZE_MASK(d->ht_size_exp[htidx0]); dictScanDefragBucket(d, fn, defragfns, privdata, &d->ht_table[htidx0][v & m0]); /* 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 { htidx0 = 0; htidx1 = 1; /* Make sure t0 is the smaller and t1 is the bigger table */ if (DICTHT_SIZE(d->ht_size_exp[htidx0]) > DICTHT_SIZE(d->ht_size_exp[htidx1])) { htidx0 = 1; htidx1 = 0; } m0 = DICTHT_SIZE_MASK(d->ht_size_exp[htidx0]); m1 = DICTHT_SIZE_MASK(d->ht_size_exp[htidx1]); dictScanDefragBucket(d, fn, defragfns, privdata, &d->ht_table[htidx0][v & m0]); /* Iterate over indices in larger table that are the expansion * of the index pointed to by the cursor in the smaller table */ do { dictScanDefragBucket(d, fn, defragfns, privdata, &d->ht_table[htidx1][v & m1]); /* 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 * resizes, we will check this allocation is allowed or not if the dict * type has resizeAllowed member function. */ static int dictTypeResizeAllowed(dict *d, size_t size) { if (d->type->resizeAllowed == NULL) return 1; return d->type->resizeAllowed( DICTHT_SIZE(_dictNextExp(size)) * sizeof(dictEntry*), (double)d->ht_used[0] / DICTHT_SIZE(d->ht_size_exp[0])); } /* Returning DICT_OK indicates a successful expand or the dictionary is undergoing rehashing, * and there is nothing else we need to do about this dictionary currently. While DICT_ERR indicates * that expand has not been triggered (may be try shrinking?)*/ int 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 (DICTHT_SIZE(d->ht_size_exp[0]) == 0) { dictExpand(d, DICT_HT_INITIAL_SIZE); return DICT_OK; } /* 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 ((dict_can_resize == DICT_RESIZE_ENABLE && d->ht_used[0] >= DICTHT_SIZE(d->ht_size_exp[0])) || (dict_can_resize != DICT_RESIZE_FORBID && d->ht_used[0] >= dict_force_resize_ratio * DICTHT_SIZE(d->ht_size_exp[0]))) { if (dictTypeResizeAllowed(d, d->ht_used[0] + 1)) dictExpand(d, d->ht_used[0] + 1); return DICT_OK; } return DICT_ERR; } /* Expand the hash table if needed (OK=Expanded, ERR=Not expanded) */ static int _dictExpandIfNeeded(dict *d) { /* Automatic resizing is disallowed. Return */ if (d->pauseAutoResize > 0) return DICT_ERR; return dictExpandIfNeeded(d); } /* Returning DICT_OK indicates a successful shrinking or the dictionary is undergoing rehashing, * and there is nothing else we need to do about this dictionary currently. While DICT_ERR indicates * that shrinking has not been triggered (may be try expanding?)*/ int dictShrinkIfNeeded(dict *d) { /* Incremental rehashing already in progress. Return. */ if (dictIsRehashing(d)) return DICT_OK; /* If the size of hash table is DICT_HT_INITIAL_SIZE, don't shrink it. */ if (DICTHT_SIZE(d->ht_size_exp[0]) <= DICT_HT_INITIAL_SIZE) return DICT_OK; /* If we reached below 1:8 elements/buckets ratio, and we are allowed to resize * the hash table (global setting) or we should avoid it but the ratio is below 1:32, * we'll trigger a resize of the hash table. */ if ((dict_can_resize == DICT_RESIZE_ENABLE && d->ht_used[0] * HASHTABLE_MIN_FILL <= DICTHT_SIZE(d->ht_size_exp[0])) || (dict_can_resize != DICT_RESIZE_FORBID && d->ht_used[0] * HASHTABLE_MIN_FILL * dict_force_resize_ratio <= DICTHT_SIZE(d->ht_size_exp[0]))) { if (dictTypeResizeAllowed(d, d->ht_used[0])) dictShrink(d, d->ht_used[0]); return DICT_OK; } return DICT_ERR; } static void _dictShrinkIfNeeded(dict *d) { /* Automatic resizing is disallowed. Return */ if (d->pauseAutoResize > 0) return; dictShrinkIfNeeded(d); } static void _dictRehashStepIfNeeded(dict *d, uint64_t visitedIdx) { if ((!dictIsRehashing(d)) || (d->pauserehash != 0)) return; /* rehashing not in progress if rehashidx == -1 */ if ((long)visitedIdx >= d->rehashidx && d->ht_table[0][visitedIdx]) { /* If we have a valid hash entry at `idx` in ht0, we perform * rehash on the bucket at `idx` (being more CPU cache friendly) */ _dictBucketRehash(d, visitedIdx); } else { /* If the hash entry is not in ht0, we rehash the buckets based * on the rehashidx (not CPU cache friendly). */ dictRehash(d,1); } } /* Our hash table capability is a power of two */ static signed char _dictNextExp(unsigned long size) { if (size <= DICT_HT_INITIAL_SIZE) return DICT_HT_INITIAL_EXP; if (size >= LONG_MAX) return (8*sizeof(long)-1); return 8*sizeof(long) - __builtin_clzl(size-1); } /* Finds and returns the link within the dict where the provided key should * be inserted using dictInsertKeyAtLink() if the key does not already exist in * the dict. If the key exists in the dict, NULL is returned and the optional * 'existing' entry pointer is populated, if provided. */ dictEntryLink dictFindLinkForInsert(dict *d, const void *key, dictEntry **existing) { unsigned long idx, table; dictCmpCache cmpCache = {0}; dictEntry *he; uint64_t hash = dictGetHash(d, key); if (existing) *existing = NULL; idx = hash & DICTHT_SIZE_MASK(d->ht_size_exp[0]); /* Rehash the hash table if needed */ _dictRehashStepIfNeeded(d,idx); /* Expand the hash table if needed */ _dictExpandIfNeeded(d); keyCmpFunc cmpFunc = dictGetCmpFunc(d); for (table = 0; table <= 1; table++) { if (table == 0 && (long)idx < d->rehashidx) continue; idx = hash & DICTHT_SIZE_MASK(d->ht_size_exp[table]); /* Search if this slot does not already contain the given key */ he = d->ht_table[table][idx]; while(he) { const void *he_key = dictStoredKey2Key(d, dictGetKey(he)); if (key == he_key || cmpFunc(&cmpCache, key, he_key)) { if (existing) *existing = he; return NULL; } he = dictGetNext(he); } if (!dictIsRehashing(d)) break; } /* If we are in the process of rehashing the hash table, the bucket is * always returned in the context of the second (new) hash table. */ dictEntry **bucket = &d->ht_table[dictIsRehashing(d) ? 1 : 0][idx]; return bucket; } void dictEmpty(dict *d, void(callback)(dict*)) { /* Someone may be monitoring a dict that started rehashing, before * destroying the dict fake completion. */ if (dictIsRehashing(d) && d->type->rehashingCompleted) d->type->rehashingCompleted(d); /* Subtract the size of all buckets. */ if (d->type->bucketChanged) d->type->bucketChanged(d, -(long long)dictBuckets(d)); _dictClear(d,0,callback); _dictClear(d,1,callback); d->rehashidx = -1; d->pauserehash = 0; d->pauseAutoResize = 0; } void dictSetResizeEnabled(dictResizeEnable enable) { dict_can_resize = enable; } /* Compiler inlines this for internal calls within dict.c (verified with -O3). */ uint64_t dictGetHash(dict *d, const void *key) { return d->type->hashFunction(key); } /* Provides the old and new ht size for a given dictionary during rehashing. This method * should only be invoked during initialization/rehashing. */ void dictRehashingInfo(dict *d, unsigned long long *from_size, unsigned long long *to_size) { /* Invalid method usage if rehashing isn't ongoing. */ assert(dictIsRehashing(d)); *from_size = DICTHT_SIZE(d->ht_size_exp[0]); *to_size = DICTHT_SIZE(d->ht_size_exp[1]); } /* ------------------------------- Debugging ---------------------------------*/ #define DICT_STATS_VECTLEN 50 void dictFreeStats(dictStats *stats) { zfree(stats->clvector); zfree(stats); } void dictCombineStats(dictStats *from, dictStats *into) { into->buckets += from->buckets; into->maxChainLen = (from->maxChainLen > into->maxChainLen) ? from->maxChainLen : into->maxChainLen; into->totalChainLen += from->totalChainLen; into->htSize += from->htSize; into->htUsed += from->htUsed; for (int i = 0; i < DICT_STATS_VECTLEN; i++) { into->clvector[i] += from->clvector[i]; } } dictStats *dictGetStatsHt(dict *d, int htidx, int full) { unsigned long *clvector = zcalloc(sizeof(unsigned long) * DICT_STATS_VECTLEN); dictStats *stats = zcalloc(sizeof(dictStats)); stats->htidx = htidx; stats->clvector = clvector; stats->htSize = DICTHT_SIZE(d->ht_size_exp[htidx]); stats->htUsed = d->ht_used[htidx]; if (!full) return stats; /* Compute stats. */ for (unsigned long i = 0; i < DICTHT_SIZE(d->ht_size_exp[htidx]); i++) { dictEntry *he; if (d->ht_table[htidx][i] == NULL) { clvector[0]++; continue; } stats->buckets++; /* For each hash entry on this slot... */ unsigned long chainlen = 0; he = d->ht_table[htidx][i]; while(he) { chainlen++; he = dictGetNext(he); } clvector[(chainlen < DICT_STATS_VECTLEN) ? chainlen : (DICT_STATS_VECTLEN-1)]++; if (chainlen > stats->maxChainLen) stats->maxChainLen = chainlen; stats->totalChainLen += chainlen; } return stats; } /* Generates human readable stats. */ size_t dictGetStatsMsg(char *buf, size_t bufsize, dictStats *stats, int full) { if (stats->htUsed == 0) { return snprintf(buf,bufsize, "Hash table %d stats (%s):\n" "No stats available for empty dictionaries\n", stats->htidx, (stats->htidx == 0) ? "main hash table" : "rehashing target"); } size_t l = 0; l += snprintf(buf + l, bufsize - l, "Hash table %d stats (%s):\n" " table size: %lu\n" " number of elements: %lu\n", stats->htidx, (stats->htidx == 0) ? "main hash table" : "rehashing target", stats->htSize, stats->htUsed); if (full) { l += snprintf(buf + l, bufsize - l, " 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", stats->buckets, stats->maxChainLen, (float) stats->totalChainLen / stats->buckets, (float) stats->htUsed / stats->buckets); for (unsigned long i = 0; i < DICT_STATS_VECTLEN - 1; i++) { if (stats->clvector[i] == 0) continue; if (l >= bufsize) break; l += snprintf(buf + l, bufsize - l, " %ld: %ld (%.02f%%)\n", i, stats->clvector[i], ((float) stats->clvector[i] / stats->htSize) * 100); } } /* Make sure there is a NULL term at the end. */ buf[bufsize-1] = '\0'; /* Unlike snprintf(), return the number of characters actually written. */ return strlen(buf); } void dictGetStats(char *buf, size_t bufsize, dict *d, int full) { size_t l; char *orig_buf = buf; size_t orig_bufsize = bufsize; dictStats *mainHtStats = dictGetStatsHt(d, 0, full); l = dictGetStatsMsg(buf, bufsize, mainHtStats, full); dictFreeStats(mainHtStats); buf += l; bufsize -= l; if (dictIsRehashing(d) && bufsize > 0) { dictStats *rehashHtStats = dictGetStatsHt(d, 1, full); dictGetStatsMsg(buf, bufsize, rehashHtStats, full); dictFreeStats(rehashHtStats); } /* Make sure there is a NULL term at the end. */ orig_buf[orig_bufsize-1] = '\0'; } static int dictDefaultCompare(dictCmpCache *cache, const void *key1, const void *key2) { (void)(cache); /*unused*/ return key1 == key2; } /* ------------------------------- Benchmark ---------------------------------*/ #ifdef REDIS_TEST #include "testhelp.h" #define UNUSED(V) ((void) V) #define TEST(name) printf("test — %s\n", name); uint64_t hashCallback(const void *key) { return dictGenHashFunction((unsigned char*)key, strlen((char*)key)); } int compareCallback(dictCmpCache *cache, const void *key1, const void *key2) { int l1,l2; UNUSED(cache); l1 = strlen((char*)key1); l2 = strlen((char*)key2); if (l1 != l2) return 0; return memcmp(key1, key2, l1) == 0; } void freeCallback(dict *d, void *val) { UNUSED(d); zfree(val); } char *stringFromLongLong(long long value) { char buf[32]; int len; char *s; len = snprintf(buf,sizeof(buf),"%lld",value); s = zmalloc(len+1); memcpy(s, buf, len); s[len] = '\0'; return s; } char *stringFromSubstring(void) { #define LARGE_STRING_SIZE 10000 #define MIN_STRING_SIZE 100 #define MAX_STRING_SIZE 500 static char largeString[LARGE_STRING_SIZE + 1]; static int init = 0; if (init == 0) { /* Generate a large string */ for (size_t i = 0; i < LARGE_STRING_SIZE; i++) { /* Random printable ASCII character (33 to 126) */ largeString[i] = 33 + (rand() % 94); } /* Null-terminate the large string */ largeString[LARGE_STRING_SIZE] = '\0'; init = 1; } /* Randomly choose a size between minSize and maxSize */ size_t substringSize = MIN_STRING_SIZE + (rand() % (MAX_STRING_SIZE - MIN_STRING_SIZE + 1)); size_t startIndex = rand() % (LARGE_STRING_SIZE - substringSize + 1); /* Allocate memory for the substring (+1 for null terminator) */ char *s = zmalloc(substringSize + 1); memcpy(s, largeString + startIndex, substringSize); // Copy the substring s[substringSize] = '\0'; // Null-terminate the string return s; } dictType BenchmarkDictType = { hashCallback, NULL, NULL, compareCallback, freeCallback, NULL, NULL }; #define start_benchmark() start = timeInMilliseconds() #define end_benchmark(msg) do { \ elapsed = timeInMilliseconds()-start; \ printf(msg ": %ld items in %lld ms\n", count, elapsed); \ } while(0) /* ./redis-server test dict [ | --accurate] */ int dictTest(int argc, char **argv, int flags) { long j; long long start, elapsed; int retval; dict *d = dictCreate(&BenchmarkDictType); dictEntry* de = NULL; dictEntry* existing = NULL; long count = 0; unsigned long new_dict_size, current_dict_used, remain_keys; int accurate = (flags & REDIS_TEST_ACCURATE); if (argc == 4) { if (accurate) { count = 5000000; } else { count = strtol(argv[3],NULL,10); } } else { count = 5000; } TEST("Add 16 keys and verify dict resize is ok") { dictSetResizeEnabled(DICT_RESIZE_ENABLE); for (j = 0; j < 16; j++) { retval = dictAdd(d,stringFromLongLong(j),(void*)j); assert(retval == DICT_OK); } while (dictIsRehashing(d)) dictRehashMicroseconds(d,1000); assert(dictSize(d) == 16); assert(dictBuckets(d) == 16); } TEST("Use DICT_RESIZE_AVOID to disable the dict resize and pad to (dict_force_resize_ratio * 16)") { /* Use DICT_RESIZE_AVOID to disable the dict resize, and pad * the number of keys to (dict_force_resize_ratio * 16), so we can satisfy * dict_force_resize_ratio in next test. */ dictSetResizeEnabled(DICT_RESIZE_AVOID); for (j = 16; j < (long)dict_force_resize_ratio * 16; j++) { retval = dictAdd(d,stringFromLongLong(j),(void*)j); assert(retval == DICT_OK); } current_dict_used = dict_force_resize_ratio * 16; assert(dictSize(d) == current_dict_used); assert(dictBuckets(d) == 16); } TEST("Add one more key, trigger the dict resize") { retval = dictAdd(d,stringFromLongLong(current_dict_used),(void*)(current_dict_used)); assert(retval == DICT_OK); current_dict_used++; new_dict_size = 1UL << _dictNextExp(current_dict_used); assert(dictSize(d) == current_dict_used); assert(DICTHT_SIZE(d->ht_size_exp[0]) == 16); assert(DICTHT_SIZE(d->ht_size_exp[1]) == new_dict_size); /* Wait for rehashing. */ dictSetResizeEnabled(DICT_RESIZE_ENABLE); while (dictIsRehashing(d)) dictRehashMicroseconds(d,1000); assert(dictSize(d) == current_dict_used); assert(DICTHT_SIZE(d->ht_size_exp[0]) == new_dict_size); assert(DICTHT_SIZE(d->ht_size_exp[1]) == 0); } TEST("Delete keys until we can trigger shrink in next test") { /* Delete keys until we can satisfy (1 / HASHTABLE_MIN_FILL) in the next test. */ for (j = new_dict_size / HASHTABLE_MIN_FILL + 1; j < (long)current_dict_used; j++) { char *key = stringFromLongLong(j); retval = dictDelete(d, key); zfree(key); assert(retval == DICT_OK); } current_dict_used = new_dict_size / HASHTABLE_MIN_FILL + 1; assert(dictSize(d) == current_dict_used); assert(DICTHT_SIZE(d->ht_size_exp[0]) == new_dict_size); assert(DICTHT_SIZE(d->ht_size_exp[1]) == 0); } TEST("Delete one more key, trigger the dict resize") { current_dict_used--; char *key = stringFromLongLong(current_dict_used); retval = dictDelete(d, key); zfree(key); unsigned long oldDictSize = new_dict_size; new_dict_size = 1UL << _dictNextExp(current_dict_used); assert(retval == DICT_OK); assert(dictSize(d) == current_dict_used); assert(DICTHT_SIZE(d->ht_size_exp[0]) == oldDictSize); assert(DICTHT_SIZE(d->ht_size_exp[1]) == new_dict_size); /* Wait for rehashing. */ while (dictIsRehashing(d)) dictRehashMicroseconds(d,1000); assert(dictSize(d) == current_dict_used); assert(DICTHT_SIZE(d->ht_size_exp[0]) == new_dict_size); assert(DICTHT_SIZE(d->ht_size_exp[1]) == 0); } TEST("Empty the dictionary and add 128 keys") { dictEmpty(d, NULL); for (j = 0; j < 128; j++) { retval = dictAdd(d,stringFromLongLong(j),(void*)j); assert(retval == DICT_OK); } while (dictIsRehashing(d)) dictRehashMicroseconds(d,1000); assert(dictSize(d) == 128); assert(dictBuckets(d) == 128); } TEST("Use DICT_RESIZE_AVOID to disable the dict resize and reduce to 3") { /* Use DICT_RESIZE_AVOID to disable the dict reset, and reduce * the number of keys until we can trigger shrinking in next test. */ dictSetResizeEnabled(DICT_RESIZE_AVOID); remain_keys = DICTHT_SIZE(d->ht_size_exp[0]) / (HASHTABLE_MIN_FILL * dict_force_resize_ratio) + 1; for (j = remain_keys; j < 128; j++) { char *key = stringFromLongLong(j); retval = dictDelete(d, key); zfree(key); assert(retval == DICT_OK); } current_dict_used = remain_keys; assert(dictSize(d) == remain_keys); assert(dictBuckets(d) == 128); } TEST("Delete one more key, trigger the dict resize") { current_dict_used--; char *key = stringFromLongLong(current_dict_used); retval = dictDelete(d, key); zfree(key); new_dict_size = 1UL << _dictNextExp(current_dict_used); assert(retval == DICT_OK); assert(dictSize(d) == current_dict_used); assert(DICTHT_SIZE(d->ht_size_exp[0]) == 128); assert(DICTHT_SIZE(d->ht_size_exp[1]) == new_dict_size); /* Wait for rehashing. */ dictSetResizeEnabled(DICT_RESIZE_ENABLE); while (dictIsRehashing(d)) dictRehashMicroseconds(d,1000); assert(dictSize(d) == current_dict_used); assert(DICTHT_SIZE(d->ht_size_exp[0]) == new_dict_size); assert(DICTHT_SIZE(d->ht_size_exp[1]) == 0); } TEST("Restore to original state") { dictEmpty(d, NULL); dictSetResizeEnabled(DICT_RESIZE_ENABLE); } srand(12345); start_benchmark(); for (j = 0; j < count; j++) { /* Create a dynamically allocated substring */ char *key = stringFromSubstring(); /* Insert the range directly from the large string */ de = dictAddRaw(d, key, &existing); assert(de != NULL || existing != NULL); /* If key already exists NULL is returned so we need to free the temp key string */ if (de == NULL) zfree(key); } end_benchmark("Inserting random substrings (100-500B) from large string with symbols"); assert((long)dictSize(d) <= count); dictEmpty(d, NULL); start_benchmark(); for (j = 0; j < count; j++) { retval = dictAdd(d,stringFromLongLong(j),(void*)j); assert(retval == DICT_OK); } end_benchmark("Inserting via dictAdd() non existing"); assert((long)dictSize(d) == count); dictEmpty(d, NULL); start_benchmark(); for (j = 0; j < count; j++) { de = dictAddRaw(d,stringFromLongLong(j),NULL); assert(de != NULL); } end_benchmark("Inserting via dictAddRaw() non existing"); assert((long)dictSize(d) == count); start_benchmark(); for (j = 0; j < count; j++) { void *key = stringFromLongLong(j); de = dictAddRaw(d,key,&existing); assert(existing != NULL); zfree(key); } end_benchmark("Inserting via dictAddRaw() existing (no insertion)"); assert((long)dictSize(d) == count); /* Wait for rehashing. */ while (dictIsRehashing(d)) { dictRehashMicroseconds(d,100*1000); } start_benchmark(); for (j = 0; j < count; j++) { char *key = stringFromLongLong(j); dictEntry *de = dictFind(d,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(d,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(d,key); assert(de != NULL); zfree(key); } end_benchmark("Random access of existing elements"); start_benchmark(); for (j = 0; j < count; j++) { dictEntry *de = dictGetRandomKey(d); 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(d,key); assert(de == NULL); zfree(key); } end_benchmark("Accessing missing"); start_benchmark(); for (j = 0; j < count; j++) { char *key = stringFromLongLong(j); retval = dictDelete(d,key); assert(retval == DICT_OK); key[0] += 17; /* Change first number to letter. */ retval = dictAdd(d,key,(void*)j); assert(retval == DICT_OK); } end_benchmark("Removing and adding"); dictRelease(d); TEST("Use dict without values (no_value=1)") { dictType dt = BenchmarkDictType; dt.no_value = 1; /* Allocate array of size count and fill it with keys (stringFromLongLong(j) */ char **lookupKeys = zmalloc(sizeof(char*) * count); for (long j = 0; j < count; j++) lookupKeys[j] = stringFromLongLong(j); /* Add keys without values. */ dict *d = dictCreate(&dt); for (j = 0; j < count; j++) { retval = dictAdd(d,lookupKeys[j],NULL); assert(retval == DICT_OK); } /* Now, we should be able to find the keys. */ for (j = 0; j < count; j++) { dictEntry *de = dictFind(d,lookupKeys[j]); assert(de != NULL); } /* Find non exists keys. */ for (j = 0; j < count; j++) { /* Temporarily override first char of key */ char tmp = lookupKeys[j][0]; lookupKeys[j][0] = 'X'; dictEntry *de = dictFind(d,lookupKeys[j]); lookupKeys[j][0] = tmp; assert(de == NULL); } dictRelease(d); zfree(lookupKeys); } TEST("Test dictFindLink() functionality") { dictType dt = BenchmarkDictType; dict *d = dictCreate(&dt); /* find in empty dict */ dictEntryLink link = dictFindLink(d, "key", NULL); assert(link == NULL); /* Add keys to dict and test */ for (j = 0; j < 10; j++) { /* Add another key to dict */ char *key = stringFromLongLong(j); retval = dictAdd(d, key, (void*)j); assert(retval == DICT_OK); /* find existing keys with dictFindLink() */ dictEntryLink link = dictFindLink(d, key, NULL); assert(link != NULL); assert(*link != NULL); assert(dictGetKey(*link) != NULL); /* Test that the key found is the correct one */ void *foundKey = dictGetKey(*link); assert(compareCallback( NULL, foundKey, key)); /* Test finding a non-existing key */ char *nonExistingKey = stringFromLongLong(j + 10); link = dictFindLink(d, nonExistingKey, NULL); assert(link == NULL); /* Test with bucket parameter */ dictEntryLink bucket = NULL; link = dictFindLink(d, key, &bucket); assert(link != NULL); assert(bucket != NULL); /* Test bucket parameter with non-existing key */ link = dictFindLink(d, nonExistingKey, &bucket); assert(link == NULL); assert(bucket != NULL); /* Bucket should still be set even for non-existing keys */ /* Clean up */ zfree(nonExistingKey); } dictRelease(d); } return 0; } #endif