236 lines
9.4 KiB
C
236 lines
9.4 KiB
C
/* Hash Tables Implementation.
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*
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* This file implements in-memory hash tables with insert/del/replace/find/
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* get-random-element operations. Hash tables will auto-resize if needed
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* tables of power of two in size are used, collisions are handled by
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* chaining. See the source code for more information... :)
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*
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* Copyright (c) 2006-Present, Redis Ltd.
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* All rights reserved.
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*
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* Licensed under your choice of the Redis Source Available License 2.0
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* (RSALv2) or the Server Side Public License v1 (SSPLv1).
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*/
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#ifndef __DICT_H
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#define __DICT_H
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#include "mt19937-64.h"
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#include <limits.h>
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#include <stdint.h>
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#include <stdlib.h>
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#define DICT_OK 0
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#define DICT_ERR 1
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/* Hash table parameters */
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#define HASHTABLE_MIN_FILL 8 /* Minimal hash table fill 12.5%(100/8) */
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typedef struct dictEntry dictEntry; /* opaque */
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typedef struct dict dict;
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typedef struct dictType {
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/* Callbacks */
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uint64_t (*hashFunction)(const void *key);
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void *(*keyDup)(dict *d, const void *key);
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void *(*valDup)(dict *d, const void *obj);
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int (*keyCompare)(dict *d, const void *key1, const void *key2);
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void (*keyDestructor)(dict *d, void *key);
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void (*valDestructor)(dict *d, void *obj);
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int (*resizeAllowed)(size_t moreMem, double usedRatio);
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/* Invoked at the start of dict initialization/rehashing (old and new ht are already created) */
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void (*rehashingStarted)(dict *d);
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/* Invoked at the end of dict initialization/rehashing of all the entries from old to new ht. Both ht still exists
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* and are cleaned up after this callback. */
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void (*rehashingCompleted)(dict *d);
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/* Allow a dict to carry extra caller-defined metadata. The
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* extra memory is initialized to 0 when a dict is allocated. */
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size_t (*dictMetadataBytes)(dict *d);
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/* Data */
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void *userdata;
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/* Flags */
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/* The 'no_value' flag, if set, indicates that values are not used, i.e. the
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* dict is a set. When this flag is set, it's not possible to access the
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* value of a dictEntry and it's also impossible to use dictSetKey(). Entry
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* metadata can also not be used. */
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unsigned int no_value:1;
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/* If no_value = 1 and all keys are odd (LSB=1), setting keys_are_odd = 1
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* enables one more optimization: to store a key without an allocated
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* dictEntry. */
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unsigned int keys_are_odd:1;
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/* TODO: Add a 'keys_are_even' flag and use a similar optimization if that
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* flag is set. */
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} dictType;
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#define DICTHT_SIZE(exp) ((exp) == -1 ? 0 : (unsigned long)1<<(exp))
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#define DICTHT_SIZE_MASK(exp) ((exp) == -1 ? 0 : (DICTHT_SIZE(exp))-1)
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struct dict {
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dictType *type;
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dictEntry **ht_table[2];
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unsigned long ht_used[2];
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long rehashidx; /* rehashing not in progress if rehashidx == -1 */
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/* Keep small vars at end for optimal (minimal) struct padding */
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int16_t pauserehash; /* If >0 rehashing is paused (<0 indicates coding error) */
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signed char ht_size_exp[2]; /* exponent of size. (size = 1<<exp) */
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int16_t pauseAutoResize; /* If >0 automatic resizing is disallowed (<0 indicates coding error) */
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void *metadata[];
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};
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/* If safe is set to 1 this is a safe iterator, that means, you can call
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* dictAdd, dictFind, and other functions against the dictionary even while
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* iterating. Otherwise it is a non safe iterator, and only dictNext()
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* should be called while iterating. */
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typedef struct dictIterator {
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dict *d;
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long index;
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int table, safe;
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dictEntry *entry, *nextEntry;
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/* unsafe iterator fingerprint for misuse detection. */
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unsigned long long fingerprint;
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} dictIterator;
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typedef struct dictStats {
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int htidx;
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unsigned long buckets;
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unsigned long maxChainLen;
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unsigned long totalChainLen;
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unsigned long htSize;
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unsigned long htUsed;
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unsigned long *clvector;
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} dictStats;
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typedef void (dictScanFunction)(void *privdata, const dictEntry *de);
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typedef void *(dictDefragAllocFunction)(void *ptr);
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typedef struct {
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dictDefragAllocFunction *defragAlloc; /* Used for entries etc. */
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dictDefragAllocFunction *defragKey; /* Defrag-realloc keys (optional) */
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dictDefragAllocFunction *defragVal; /* Defrag-realloc values (optional) */
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} dictDefragFunctions;
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/* This is the initial size of every hash table */
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#define DICT_HT_INITIAL_EXP 2
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#define DICT_HT_INITIAL_SIZE (1<<(DICT_HT_INITIAL_EXP))
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/* ------------------------------- Macros ------------------------------------*/
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#define dictFreeVal(d, entry) do { \
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if ((d)->type->valDestructor) \
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(d)->type->valDestructor((d), dictGetVal(entry)); \
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} while(0)
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#define dictFreeKey(d, entry) \
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if ((d)->type->keyDestructor) \
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(d)->type->keyDestructor((d), dictGetKey(entry))
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#define dictCompareKeys(d, key1, key2) \
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(((d)->type->keyCompare) ? \
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(d)->type->keyCompare((d), key1, key2) : \
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(key1) == (key2))
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#define dictMetadata(d) (&(d)->metadata)
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#define dictMetadataSize(d) ((d)->type->dictMetadataBytes \
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? (d)->type->dictMetadataBytes(d) : 0)
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#define dictHashKey(d, key) ((d)->type->hashFunction(key))
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#define dictBuckets(d) (DICTHT_SIZE((d)->ht_size_exp[0])+DICTHT_SIZE((d)->ht_size_exp[1]))
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#define dictSize(d) ((d)->ht_used[0]+(d)->ht_used[1])
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#define dictIsEmpty(d) ((d)->ht_used[0] == 0 && (d)->ht_used[1] == 0)
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#define dictIsRehashing(d) ((d)->rehashidx != -1)
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#define dictPauseRehashing(d) ((d)->pauserehash++)
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#define dictResumeRehashing(d) ((d)->pauserehash--)
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#define dictIsRehashingPaused(d) ((d)->pauserehash > 0)
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#define dictPauseAutoResize(d) ((d)->pauseAutoResize++)
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#define dictResumeAutoResize(d) ((d)->pauseAutoResize--)
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/* If our unsigned long type can store a 64 bit number, use a 64 bit PRNG. */
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#if ULONG_MAX >= 0xffffffffffffffff
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#define randomULong() ((unsigned long) genrand64_int64())
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#else
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#define randomULong() random()
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#endif
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typedef enum {
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DICT_RESIZE_ENABLE,
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DICT_RESIZE_AVOID,
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DICT_RESIZE_FORBID,
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} dictResizeEnable;
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/* API */
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dict *dictCreate(dictType *type);
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int dictExpand(dict *d, unsigned long size);
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int dictTryExpand(dict *d, unsigned long size);
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int dictShrink(dict *d, unsigned long size);
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int dictAdd(dict *d, void *key, void *val);
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dictEntry *dictAddRaw(dict *d, void *key, dictEntry **existing);
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void *dictFindPositionForInsert(dict *d, const void *key, dictEntry **existing);
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dictEntry *dictInsertAtPosition(dict *d, void *key, void *position);
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dictEntry *dictAddOrFind(dict *d, void *key);
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int dictReplace(dict *d, void *key, void *val);
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int dictDelete(dict *d, const void *key);
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dictEntry *dictUnlink(dict *d, const void *key);
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void dictFreeUnlinkedEntry(dict *d, dictEntry *he);
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dictEntry *dictTwoPhaseUnlinkFind(dict *d, const void *key, dictEntry ***plink, int *table_index);
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void dictTwoPhaseUnlinkFree(dict *d, dictEntry *he, dictEntry **plink, int table_index);
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void dictRelease(dict *d);
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dictEntry * dictFind(dict *d, const void *key);
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void *dictFetchValue(dict *d, const void *key);
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int dictShrinkIfNeeded(dict *d);
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int dictExpandIfNeeded(dict *d);
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void dictSetKey(dict *d, dictEntry* de, void *key);
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void dictSetVal(dict *d, dictEntry *de, void *val);
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void dictSetSignedIntegerVal(dictEntry *de, int64_t val);
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void dictSetUnsignedIntegerVal(dictEntry *de, uint64_t val);
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void dictSetDoubleVal(dictEntry *de, double val);
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int64_t dictIncrSignedIntegerVal(dictEntry *de, int64_t val);
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uint64_t dictIncrUnsignedIntegerVal(dictEntry *de, uint64_t val);
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double dictIncrDoubleVal(dictEntry *de, double val);
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void *dictEntryMetadata(dictEntry *de);
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void *dictGetKey(const dictEntry *de);
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void *dictGetVal(const dictEntry *de);
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int64_t dictGetSignedIntegerVal(const dictEntry *de);
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uint64_t dictGetUnsignedIntegerVal(const dictEntry *de);
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double dictGetDoubleVal(const dictEntry *de);
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double *dictGetDoubleValPtr(dictEntry *de);
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size_t dictMemUsage(const dict *d);
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size_t dictEntryMemUsage(void);
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dictIterator *dictGetIterator(dict *d);
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dictIterator *dictGetSafeIterator(dict *d);
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void dictInitIterator(dictIterator *iter, dict *d);
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void dictInitSafeIterator(dictIterator *iter, dict *d);
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void dictResetIterator(dictIterator *iter);
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dictEntry *dictNext(dictIterator *iter);
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void dictReleaseIterator(dictIterator *iter);
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dictEntry *dictGetRandomKey(dict *d);
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dictEntry *dictGetFairRandomKey(dict *d);
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unsigned int dictGetSomeKeys(dict *d, dictEntry **des, unsigned int count);
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void dictGetStats(char *buf, size_t bufsize, dict *d, int full);
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uint64_t dictGenHashFunction(const void *key, size_t len);
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uint64_t dictGenCaseHashFunction(const unsigned char *buf, size_t len);
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void dictEmpty(dict *d, void(callback)(dict*));
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void dictSetResizeEnabled(dictResizeEnable enable);
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int dictRehash(dict *d, int n);
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int dictRehashMicroseconds(dict *d, uint64_t us);
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void dictSetHashFunctionSeed(uint8_t *seed);
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uint8_t *dictGetHashFunctionSeed(void);
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unsigned long dictScan(dict *d, unsigned long v, dictScanFunction *fn, void *privdata);
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unsigned long dictScanDefrag(dict *d, unsigned long v, dictScanFunction *fn, dictDefragFunctions *defragfns, void *privdata);
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uint64_t dictGetHash(dict *d, const void *key);
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dictEntry *dictFindEntryByPtrAndHash(dict *d, const void *oldptr, uint64_t hash);
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void dictRehashingInfo(dict *d, unsigned long long *from_size, unsigned long long *to_size);
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size_t dictGetStatsMsg(char *buf, size_t bufsize, dictStats *stats, int full);
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dictStats* dictGetStatsHt(dict *d, int htidx, int full);
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void dictCombineStats(dictStats *from, dictStats *into);
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void dictFreeStats(dictStats *stats);
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#ifdef REDIS_TEST
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int dictTest(int argc, char *argv[], int flags);
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#endif
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#endif /* __DICT_H */
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