codekingpro/portable-devtools

1/*-------------------------------------------------------------------------2 *3 * hsearch.h4 *	  exported definitions for utils/hash/dynahash.c; see notes therein5 *6 *7 * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group8 * Portions Copyright (c) 1994, Regents of the University of California9 *10 * src/include/utils/hsearch.h11 *12 *-------------------------------------------------------------------------13 */14#ifndef HSEARCH_H15#define HSEARCH_H16 17 18/*19 * Hash functions must have this signature.20 */21typedef uint32 (*HashValueFunc) (const void *key, Size keysize);22 23/*24 * Key comparison functions must have this signature.  Comparison functions25 * return zero for match, nonzero for no match.  (The comparison function26 * definition is designed to allow memcmp() and strncmp() to be used directly27 * as key comparison functions.)28 */29typedef int (*HashCompareFunc) (const void *key1, const void *key2,30								Size keysize);31 32/*33 * Key copying functions must have this signature.  The return value is not34 * used.  (The definition is set up to allow memcpy() and strlcpy() to be35 * used directly.)36 */37typedef void *(*HashCopyFunc) (void *dest, const void *src, Size keysize);38 39/*40 * Space allocation function for a hashtable --- designed to match malloc().41 * Note: there is no free function API; can't destroy a hashtable unless you42 * use the default allocator.43 */44typedef void *(*HashAllocFunc) (Size request);45 46/*47 * HASHELEMENT is the private part of a hashtable entry.  The caller's data48 * follows the HASHELEMENT structure (on a MAXALIGN'd boundary).  The hash key49 * is expected to be at the start of the caller's hash entry data structure.50 */51typedef struct HASHELEMENT52{53	struct HASHELEMENT *link;	/* link to next entry in same bucket */54	uint32		hashvalue;		/* hash function result for this entry */55} HASHELEMENT;56 57/* Hash table header struct is an opaque type known only within dynahash.c */58typedef struct HASHHDR HASHHDR;59 60/* Hash table control struct is an opaque type known only within dynahash.c */61typedef struct HTAB HTAB;62 63/* Parameter data structure for hash_create */64/* Only those fields indicated by hash_flags need be set */65typedef struct HASHCTL66{67	/* Used if HASH_PARTITION flag is set: */68	long		num_partitions; /* # partitions (must be power of 2) */69	/* Used if HASH_SEGMENT flag is set: */70	long		ssize;			/* segment size */71	/* Used if HASH_DIRSIZE flag is set: */72	long		dsize;			/* (initial) directory size */73	long		max_dsize;		/* limit to dsize if dir size is limited */74	/* Used if HASH_ELEM flag is set (which is now required): */75	Size		keysize;		/* hash key length in bytes */76	Size		entrysize;		/* total user element size in bytes */77	/* Used if HASH_FUNCTION flag is set: */78	HashValueFunc hash;			/* hash function */79	/* Used if HASH_COMPARE flag is set: */80	HashCompareFunc match;		/* key comparison function */81	/* Used if HASH_KEYCOPY flag is set: */82	HashCopyFunc keycopy;		/* key copying function */83	/* Used if HASH_ALLOC flag is set: */84	HashAllocFunc alloc;		/* memory allocator */85	/* Used if HASH_CONTEXT flag is set: */86	MemoryContext hcxt;			/* memory context to use for allocations */87	/* Used if HASH_SHARED_MEM flag is set: */88	HASHHDR    *hctl;			/* location of header in shared mem */89} HASHCTL;90 91/* Flag bits for hash_create; most indicate which parameters are supplied */92#define HASH_PARTITION	0x0001	/* Hashtable is used w/partitioned locking */93#define HASH_SEGMENT	0x0002	/* Set segment size */94#define HASH_DIRSIZE	0x0004	/* Set directory size (initial and max) */95#define HASH_ELEM		0x0008	/* Set keysize and entrysize (now required!) */96#define HASH_STRINGS	0x0010	/* Select support functions for string keys */97#define HASH_BLOBS		0x0020	/* Select support functions for binary keys */98#define HASH_FUNCTION	0x0040	/* Set user defined hash function */99#define HASH_COMPARE	0x0080	/* Set user defined comparison function */100#define HASH_KEYCOPY	0x0100	/* Set user defined key-copying function */101#define HASH_ALLOC		0x0200	/* Set memory allocator */102#define HASH_CONTEXT	0x0400	/* Set memory allocation context */103#define HASH_SHARED_MEM 0x0800	/* Hashtable is in shared memory */104#define HASH_ATTACH		0x1000	/* Do not initialize hctl */105#define HASH_FIXED_SIZE 0x2000	/* Initial size is a hard limit */106 107/* max_dsize value to indicate expansible directory */108#define NO_MAX_DSIZE			(-1)109 110/* hash_search operations */111typedef enum112{113	HASH_FIND,114	HASH_ENTER,115	HASH_REMOVE,116	HASH_ENTER_NULL117} HASHACTION;118 119/* hash_seq status (should be considered an opaque type by callers) */120typedef struct121{122	HTAB	   *hashp;123	uint32		curBucket;		/* index of current bucket */124	HASHELEMENT *curEntry;		/* current entry in bucket */125} HASH_SEQ_STATUS;126 127/*128 * prototypes for functions in dynahash.c129 */130extern HTAB *hash_create(const char *tabname, long nelem,131						 const HASHCTL *info, int flags);132extern void hash_destroy(HTAB *hashp);133extern void hash_stats(const char *where, HTAB *hashp);134extern void *hash_search(HTAB *hashp, const void *keyPtr, HASHACTION action,135						 bool *foundPtr);136extern uint32 get_hash_value(HTAB *hashp, const void *keyPtr);137extern void *hash_search_with_hash_value(HTAB *hashp, const void *keyPtr,138										 uint32 hashvalue, HASHACTION action,139										 bool *foundPtr);140extern bool hash_update_hash_key(HTAB *hashp, void *existingEntry,141								 const void *newKeyPtr);142extern long hash_get_num_entries(HTAB *hashp);143extern void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp);144extern void *hash_seq_search(HASH_SEQ_STATUS *status);145extern void hash_seq_term(HASH_SEQ_STATUS *status);146extern void hash_freeze(HTAB *hashp);147extern Size hash_estimate_size(long num_entries, Size entrysize);148extern long hash_select_dirsize(long num_entries);149extern Size hash_get_shared_size(HASHCTL *info, int flags);150extern void AtEOXact_HashTables(bool isCommit);151extern void AtEOSubXact_HashTables(bool isCommit, int nestDepth);152 153#endif							/* HSEARCH_H */154