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Diffstat (limited to 'db2/lock/lock_util.c')
| -rw-r--r-- | db2/lock/lock_util.c | 152 |
1 files changed, 0 insertions, 152 deletions
diff --git a/db2/lock/lock_util.c b/db2/lock/lock_util.c deleted file mode 100644 index 29da75b8a8..0000000000 --- a/db2/lock/lock_util.c +++ /dev/null @@ -1,152 +0,0 @@ -/*- - * See the file LICENSE for redistribution information. - * - * Copyright (c) 1996, 1997, 1998 - * Sleepycat Software. All rights reserved. - */ - -#include "config.h" - -#ifndef lint -static const char sccsid[] = "@(#)lock_util.c 10.10 (Sleepycat) 9/20/98"; -#endif /* not lint */ - -#ifndef NO_SYSTEM_INCLUDES -#include <sys/types.h> - -#include <string.h> -#endif - -#include "db_int.h" -#include "shqueue.h" -#include "db_page.h" -#include "db_shash.h" -#include "hash.h" -#include "lock.h" - -/* - * __lock_cmp -- - * This function is used to compare a DBT that is about to be entered - * into a hash table with an object already in the hash table. Note - * that it just returns true on equal and 0 on not-equal. Therefore - * this function cannot be used as a sort function; its purpose is to - * be used as a hash comparison function. - * - * PUBLIC: int __lock_cmp __P((const DBT *, DB_LOCKOBJ *)); - */ -int -__lock_cmp(dbt, lock_obj) - const DBT *dbt; - DB_LOCKOBJ *lock_obj; -{ - void *obj_data; - - if (lock_obj->type != DB_LOCK_OBJTYPE) - return (0); - - obj_data = SH_DBT_PTR(&lock_obj->lockobj); - return (dbt->size == lock_obj->lockobj.size && - memcmp(dbt->data, obj_data, dbt->size) == 0); -} - -/* - * PUBLIC: int __lock_locker_cmp __P((u_int32_t, DB_LOCKOBJ *)); - */ -int -__lock_locker_cmp(locker, lock_obj) - u_int32_t locker; - DB_LOCKOBJ *lock_obj; -{ - void *obj_data; - - if (lock_obj->type != DB_LOCK_LOCKER) - return (0); - - obj_data = SH_DBT_PTR(&lock_obj->lockobj); - return (memcmp(&locker, obj_data, sizeof(u_int32_t)) == 0); -} - -/* - * The next two functions are the hash functions used to store objects in the - * lock hash table. They are hashing the same items, but one (__lock_ohash) - * takes a DBT (used for hashing a parameter passed from the user) and the - * other (__lock_lhash) takes a DB_LOCKOBJ (used for hashing something that is - * already in the lock manager). In both cases, we have a special check to - * fast path the case where we think we are doing a hash on a DB page/fileid - * pair. If the size is right, then we do the fast hash. - * - * We know that DB uses DB_LOCK_ILOCK types for its lock objects. The first - * four bytes are the 4-byte page number and the next DB_FILE_ID_LEN bytes - * are a unique file id, where the first 4 bytes on UNIX systems are the file - * inode number, and the first 4 bytes on Windows systems are the FileIndexLow - * bytes. So, we use the XOR of the page number and the first four bytes of - * the file id to produce a 32-bit hash value. - * - * We have no particular reason to believe that this algorithm will produce - * a good hash, but we want a fast hash more than we want a good one, when - * we're coming through this code path. - */ -#define FAST_HASH(P) { \ - u_int32_t __h; \ - u_int8_t *__cp, *__hp; \ - __hp = (u_int8_t *)&__h; \ - __cp = (u_int8_t *)(P); \ - __hp[0] = __cp[0] ^ __cp[4]; \ - __hp[1] = __cp[1] ^ __cp[5]; \ - __hp[2] = __cp[2] ^ __cp[6]; \ - __hp[3] = __cp[3] ^ __cp[7]; \ - return (__h); \ -} - -/* - * __lock_ohash -- - * - * PUBLIC: u_int32_t __lock_ohash __P((const DBT *)); - */ -u_int32_t -__lock_ohash(dbt) - const DBT *dbt; -{ - if (dbt->size == sizeof(DB_LOCK_ILOCK)) - FAST_HASH(dbt->data); - - return (__ham_func5(dbt->data, dbt->size)); -} - -/* - * __lock_lhash -- - * - * PUBLIC: u_int32_t __lock_lhash __P((DB_LOCKOBJ *)); - */ -u_int32_t -__lock_lhash(lock_obj) - DB_LOCKOBJ *lock_obj; -{ - u_int32_t tmp; - void *obj_data; - - obj_data = SH_DBT_PTR(&lock_obj->lockobj); - if (lock_obj->type == DB_LOCK_LOCKER) { - memcpy(&tmp, obj_data, sizeof(u_int32_t)); - return (tmp); - } - - if (lock_obj->lockobj.size == sizeof(DB_LOCK_ILOCK)) - FAST_HASH(obj_data); - - return (__ham_func5(obj_data, lock_obj->lockobj.size)); -} - -/* - * __lock_locker_hash -- - * Hash function for entering lockers into the hash table. Since these - * are simply 32-bit unsigned integers, just return the locker value. - * - * PUBLIC: u_int32_t __lock_locker_hash __P((u_int32_t)); - */ -u_int32_t -__lock_locker_hash(locker) - u_int32_t locker; -{ - return (locker); -} |