| /*------------------------------------------------------------------------- |
| * |
| * hsearch.h |
| * exported definitions for utils/hash/dynahash.c; see notes therein |
| * |
| * |
| * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group |
| * Portions Copyright (c) 1994, Regents of the University of California |
| * |
| * $PostgreSQL: pgsql/src/include/utils/hsearch.h,v 1.45.2.1 2007/04/26 23:24:57 tgl Exp $ |
| * |
| *------------------------------------------------------------------------- |
| */ |
| #ifndef HSEARCH_H |
| #define HSEARCH_H |
| |
| |
| /* |
| * Hash functions must have this signature. |
| */ |
| typedef uint32 (*HashValueFunc) (const void *key, Size keysize); |
| |
| /* |
| * Key comparison functions must have this signature. Comparison functions |
| * return zero for match, nonzero for no match. (The comparison function |
| * definition is designed to allow memcmp() and strncmp() to be used directly |
| * as key comparison functions.) |
| */ |
| typedef int (*HashCompareFunc) (const void *key1, const void *key2, |
| Size keysize); |
| |
| /* |
| * Key copying functions must have this signature. The return value is not |
| * used. (The definition is set up to allow memcpy() and strncpy() to be |
| * used directly.) |
| */ |
| typedef void *(*HashCopyFunc) (void *dest, const void *src, Size keysize); |
| |
| /* |
| * Space allocation function for a hashtable --- designed to match malloc(). |
| * Note: there is no free function API; can't destroy a hashtable unless you |
| * use the default allocator. |
| */ |
| typedef void *(*HashAllocFunc) (Size request); |
| |
| /* |
| * HASHELEMENT is the private part of a hashtable entry. The caller's data |
| * follows the HASHELEMENT structure (on a MAXALIGN'd boundary). The hash key |
| * is expected to be at the start of the caller's hash entry data structure. |
| */ |
| typedef struct HASHELEMENT |
| { |
| struct HASHELEMENT *link; /* link to next entry in same bucket */ |
| uint32 hashvalue; /* hash function result for this entry */ |
| } HASHELEMENT; |
| |
| /* Hash table header struct is an opaque type known only within dynahash.c */ |
| typedef struct HASHHDR HASHHDR; |
| |
| /* Hash table control struct is an opaque type known only within dynahash.c */ |
| typedef struct HTAB HTAB; |
| |
| /* Parameter data structure for hash_create */ |
| /* Only those fields indicated by hash_flags need be set */ |
| typedef struct HASHCTL |
| { |
| long num_partitions; /* # partitions (must be power of 2) */ |
| long ssize; /* segment size */ |
| long dsize; /* (initial) directory size */ |
| long max_dsize; /* limit to dsize if dir size is limited */ |
| long ffactor; /* fill factor */ |
| Size keysize; /* hash key length in bytes */ |
| Size entrysize; /* total user element size in bytes */ |
| HashValueFunc hash; /* hash function */ |
| HashCompareFunc match; /* key comparison function */ |
| HashCopyFunc keycopy; /* key copying function */ |
| HashAllocFunc alloc; /* memory allocator */ |
| MemoryContext hcxt; /* memory context to use for allocations */ |
| HASHHDR *hctl; /* location of header in shared mem */ |
| } HASHCTL; |
| |
| /* Flags to indicate which parameters are supplied */ |
| #define HASH_PARTITION 0x001 /* Hashtable is used w/partitioned locking */ |
| #define HASH_SEGMENT 0x002 /* Set segment size */ |
| #define HASH_DIRSIZE 0x004 /* Set directory size (initial and max) */ |
| #define HASH_FFACTOR 0x008 /* Set fill factor */ |
| #define HASH_FUNCTION 0x010 /* Set user defined hash function */ |
| #define HASH_ELEM 0x020 /* Set keysize and entrysize */ |
| #define HASH_SHARED_MEM 0x040 /* Hashtable is in shared memory */ |
| #define HASH_ATTACH 0x080 /* Do not initialize hctl */ |
| #define HASH_ALLOC 0x100 /* Set memory allocator */ |
| #define HASH_CONTEXT 0x200 /* Set memory allocation context */ |
| #define HASH_COMPARE 0x400 /* Set user defined comparison function */ |
| #define HASH_KEYCOPY 0x800 /* Set user defined key-copying function */ |
| |
| |
| /* max_dsize value to indicate expansible directory */ |
| #define NO_MAX_DSIZE (-1) |
| |
| /* hash_search operations */ |
| typedef enum |
| { |
| HASH_FIND, |
| HASH_ENTER, |
| HASH_REMOVE, |
| HASH_ENTER_NULL |
| } HASHACTION; |
| |
| /* hash_seq status (should be considered an opaque type by callers) */ |
| typedef struct |
| { |
| HTAB *hashp; |
| uint32 curBucket; /* index of current bucket */ |
| HASHELEMENT *curEntry; /* current entry in bucket */ |
| } HASH_SEQ_STATUS; |
| |
| /* |
| * prototypes for functions in dynahash.c |
| */ |
| extern HTAB *hash_create(const char *tabname, long nelem, |
| HASHCTL *info, int flags); |
| extern void hash_destroy(HTAB *hashp); |
| extern void hash_stats(const char *where, HTAB *hashp); |
| extern void *hash_search(HTAB *hashp, const void *keyPtr, HASHACTION action, |
| bool *foundPtr); |
| extern uint32 get_hash_value(HTAB *hashp, const void *keyPtr); |
| extern void *hash_search_with_hash_value(HTAB *hashp, const void *keyPtr, |
| uint32 hashvalue, HASHACTION action, |
| bool *foundPtr); |
| extern long hash_get_num_entries(HTAB *hashp); |
| extern void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp); |
| extern void *hash_seq_search(HASH_SEQ_STATUS *status); |
| extern void hash_seq_term(HASH_SEQ_STATUS *status); |
| extern void hash_freeze(HTAB *hashp); |
| extern Size hash_estimate_size(long num_entries, Size entrysize); |
| extern long hash_select_dirsize(long num_entries); |
| extern Size hash_get_shared_size(HASHCTL *info, int flags); |
| extern void AtEOXact_HashTables(bool isCommit); |
| extern void AtEOSubXact_HashTables(bool isCommit, int nestDepth); |
| |
| /* |
| * prototypes for functions in hashfn.c |
| */ |
| extern uint32 string_hash(const void *key, Size keysize); |
| extern uint32 tag_hash(const void *key, Size keysize); |
| extern uint32 oid_hash(const void *key, Size keysize); |
| extern uint32 bitmap_hash(const void *key, Size keysize); |
| extern int bitmap_match(const void *key1, const void *key2, Size keysize); |
| extern uint32 int32_hash(const void *key, Size keysize); |
| |
| #endif /* HSEARCH_H */ |