1 files changed, 153 insertions, 0 deletions
diff --git a/src/include/utils/hsearch.h b/src/include/utils/hsearch.h
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@@ -0,0 +1,153 @@
+/*-------------------------------------------------------------------------
+ *
+ * hsearch.h
+ *	  exported definitions for utils/hash/dynahash.c; see notes therein
+ *
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/utils/hsearch.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#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 strlcpy() 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
+{
+	/* Used if HASH_PARTITION flag is set: */
+	long		num_partitions; /* # partitions (must be power of 2) */
+	/* Used if HASH_SEGMENT flag is set: */
+	long		ssize;			/* segment size */
+	/* Used if HASH_DIRSIZE flag is set: */
+	long		dsize;			/* (initial) directory size */
+	long		max_dsize;		/* limit to dsize if dir size is limited */
+	/* Used if HASH_ELEM flag is set (which is now required): */
+	Size		keysize;		/* hash key length in bytes */
+	Size		entrysize;		/* total user element size in bytes */
+	/* Used if HASH_FUNCTION flag is set: */
+	HashValueFunc hash;			/* hash function */
+	/* Used if HASH_COMPARE flag is set: */
+	HashCompareFunc match;		/* key comparison function */
+	/* Used if HASH_KEYCOPY flag is set: */
+	HashCopyFunc keycopy;		/* key copying function */
+	/* Used if HASH_ALLOC flag is set: */
+	HashAllocFunc alloc;		/* memory allocator */
+	/* Used if HASH_CONTEXT flag is set: */
+	MemoryContext hcxt;			/* memory context to use for allocations */
+	/* Used if HASH_SHARED_MEM flag is set: */
+	HASHHDR    *hctl;			/* location of header in shared mem */
+} HASHCTL;
+
+/* Flag bits for hash_create; most indicate which parameters are supplied */
+#define HASH_PARTITION	0x0001	/* Hashtable is used w/partitioned locking */
+#define HASH_SEGMENT	0x0002	/* Set segment size */
+#define HASH_DIRSIZE	0x0004	/* Set directory size (initial and max) */
+#define HASH_ELEM		0x0008	/* Set keysize and entrysize (now required!) */
+#define HASH_STRINGS	0x0010	/* Select support functions for string keys */
+#define HASH_BLOBS		0x0020	/* Select support functions for binary keys */
+#define HASH_FUNCTION	0x0040	/* Set user defined hash function */
+#define HASH_COMPARE	0x0080	/* Set user defined comparison function */
+#define HASH_KEYCOPY	0x0100	/* Set user defined key-copying function */
+#define HASH_ALLOC		0x0200	/* Set memory allocator */
+#define HASH_CONTEXT	0x0400	/* Set memory allocation context */
+#define HASH_SHARED_MEM 0x0800	/* Hashtable is in shared memory */
+#define HASH_ATTACH		0x1000	/* Do not initialize hctl */
+#define HASH_FIXED_SIZE 0x2000	/* Initial size is a hard limit */
+
+/* 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,
+						 const 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 bool hash_update_hash_key(HTAB *hashp, void *existingEntry,
+								 const void *newKeyPtr);
+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);
+
+#endif							/* HSEARCH_H */