You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
109 lines
3.6 KiB
109 lines
3.6 KiB
3 years ago
|
/*-
|
||
|
|
* See the file LICENSE for redistribution information.
|
||
|
|
*
|
||
|
|
* Copyright (c) 1996, 1997, 1998, 1999
|
||
|
|
* Sleepycat Software. All rights reserved.
|
||
|
|
*
|
||
|
|
* @(#)db_shash.h 11.2 (Sleepycat) 9/23/99
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* Hash Headers */
|
||
|
|
typedef SH_TAILQ_HEAD(__hash_head) DB_HASHTAB;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* HASHACCESS --
|
||
|
|
*
|
||
|
|
* Figure out to which bucket an item belongs and lock that bucket,
|
||
|
|
* returning the bucket index.
|
||
|
|
*
|
||
|
|
* synch: beginning of the array of mutexes that protect the table.
|
||
|
|
* elt: the item on which we're computing the hash function.
|
||
|
|
* nelems: the number of buckets in the hash table.
|
||
|
|
* hash: the hash function that operates on elements of the type of elt
|
||
|
|
* ndx: the index into the hash/synch array that we're locking.
|
||
|
|
* fh: the locking file handle.
|
||
|
|
*/
|
||
|
|
#define HASHACCESS(synch, elt, nelems, hash, ndx, fh) do { \
|
||
|
|
ndx = hash(elt) % (nelems); \
|
||
|
|
MUTEX_LOCK(&synch[ndx], fh); \
|
||
|
|
} while(0)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* HASHRELEASE --
|
||
|
|
*
|
||
|
|
* Release a hash bucket that we have locked.
|
||
|
|
*
|
||
|
|
* synch: beginning of the array of mutexes that protect the table.
|
||
|
|
* ndx: the index into the hash/synch array that we're locking.
|
||
|
|
* fh: the locking file handle.
|
||
|
|
*/
|
||
|
|
#define HASHRELEASE(synch, ndx, fh) do { \
|
||
|
|
MUTEX_UNLOCK(&synch[ndx]); \
|
||
|
|
} while(0)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* HASHLOOKUP --
|
||
|
|
*
|
||
|
|
* Look up something in a shared memory hash table. The "elt" argument
|
||
|
|
* should be a key, and cmp_func must know how to compare a key to whatever
|
||
|
|
* structure it is that appears in the hash table. The comparison function
|
||
|
|
*
|
||
|
|
* begin: address of the beginning of the hash table.
|
||
|
|
* ndx: index into table for this item.
|
||
|
|
* type: the structure type of the elements that are linked in each bucket.
|
||
|
|
* field: the name of the field by which the "type" structures are linked.
|
||
|
|
* elt: the item for which we are searching in the hash table.
|
||
|
|
* res: the variable into which we'll store the element if we find it.
|
||
|
|
* cmp: called as: cmp(lookup_elt, table_elt).
|
||
|
|
*
|
||
|
|
* If the element is not in the hash table, this macro exits with res set
|
||
|
|
* to NULL.
|
||
|
|
*/
|
||
|
|
#define HASHLOOKUP(begin, ndx, type, field, elt, res, cmp) do { \
|
||
|
|
DB_HASHTAB *__bucket; \
|
||
|
|
\
|
||
|
|
__bucket = &begin[ndx]; \
|
||
|
|
for (res = SH_TAILQ_FIRST(__bucket, type); \
|
||
|
|
res != NULL; res = SH_TAILQ_NEXT(res, field, type)) \
|
||
|
|
if (cmp(elt, res)) \
|
||
|
|
break; \
|
||
|
|
} while(0)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* HASHINSERT --
|
||
|
|
*
|
||
|
|
* Insert a new entry into the hash table. This assumes that you already
|
||
|
|
* have the bucket locked and that lookup has failed; don't call it if you
|
||
|
|
* haven't already called HASHLOOKUP. If you do, you could get duplicate
|
||
|
|
* entries.
|
||
|
|
*
|
||
|
|
* begin: the beginning address of the hash table.
|
||
|
|
* ndx: the index for this element.
|
||
|
|
* type: the structure type of the elements that are linked in each bucket.
|
||
|
|
* field: the name of the field by which the "type" structures are linked.
|
||
|
|
* elt: the item to be inserted.
|
||
|
|
*/
|
||
|
|
#define HASHINSERT(begin, ndx, type, field, elt) do { \
|
||
|
|
DB_HASHTAB *__bucket; \
|
||
|
|
\
|
||
|
|
__bucket = &begin[ndx]; \
|
||
|
|
SH_TAILQ_INSERT_HEAD(__bucket, elt, field, type); \
|
||
|
|
} while(0)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* HASHREMOVE_EL --
|
||
|
|
* Given the object "obj" in the table, remove it.
|
||
|
|
*
|
||
|
|
* begin: address of the beginning of the hash table.
|
||
|
|
* ndx: index into hash table of where this element belongs.
|
||
|
|
* type: the structure type of the elements that are linked in each bucket.
|
||
|
|
* field: the name of the field by which the "type" structures are linked.
|
||
|
|
* obj: the object in the table that we with to delete.
|
||
|
|
*/
|
||
|
|
#define HASHREMOVE_EL(begin, ndx, type, field, obj) { \
|
||
|
|
DB_HASHTAB *__bucket; \
|
||
|
|
\
|
||
|
|
__bucket = &begin[ndx]; \
|
||
|
|
SH_TAILQ_REMOVE(__bucket, obj, field, type); \
|
||
|
|
}
|