Improve hash_create's API for selecting simple-binary-key hash functions.

[postgresql] / src / include / utils / hsearch.h

diff --git a/src/include/utils/hsearch.h b/src/include/utils/hsearch.h
index c53d93e3969977051b17953e4ccdf5e4d6d8cf99..dfdf658ddf0dcacbca98885073798eb4be0da03b 100644 (file)
--- a/src/include/utils/hsearch.h
+++ b/src/include/utils/hsearch.h
@@ -4,7 +4,7 @@
  *       exported definitions for utils/hash/dynahash.c; see notes therein
  *
  *
- * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * src/include/utils/hsearch.h
@@ -30,8 +30,8 @@ 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
+ * 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);
@@ -80,19 +80,20 @@ typedef struct HASHCTL
 } 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 */
-#define HASH_FIXED_SIZE 0x1000 /* Initial size is a hard limit */
+#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_FFACTOR   0x0008  /* Set fill factor */
+#define HASH_ELEM              0x0010  /* Set keysize and entrysize */
+#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 */
@@ -128,6 +129,8 @@ 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);
@@ -141,11 +144,17 @@ extern void AtEOSubXact_HashTables(bool isCommit, int nestDepth);
 
 /*
  * prototypes for functions in hashfn.c
+ *
+ * Note: It is deprecated for callers of hash_create to explicitly specify
+ * string_hash, tag_hash, uint32_hash, or oid_hash.  Just set HASH_BLOBS or
+ * not.  Use HASH_FUNCTION only when you want something other than those.
  */
 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 uint32_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);
 
+#define oid_hash uint32_hash   /* Remove me eventually */
+
 #endif   /* HSEARCH_H */