Update to db 2.3.10.
[kopensolaris-gnu/glibc.git] / db2 / include / db_shash.h
1 /*-
2  * See the file LICENSE for redistribution information.
3  *
4  * Copyright (c) 1996, 1997
5  *      Sleepycat Software.  All rights reserved.
6  *
7  *      @(#)db_shash.h  10.2 (Sleepycat) 9/16/97
8  */
9
10 /* Hash Headers */
11 typedef SH_TAILQ_HEAD(hash_head) DB_HASHTAB;
12
13 /*
14  * HASHLOOKUP --
15  *
16  * Look up something in a shared memory hash table.  The "elt" argument
17  * should be a key, and cmp_func must know how to compare a key to whatever
18  * structure it is that appears in the hash table.  The comparison function
19  * cmp_func is called as: cmp_func(lookup_elt, table_elt);
20  * begin: address of the beginning of the hash table.
21  * type: the structure type of the elements that are linked in each bucket.
22  * field: the name of the field by which the "type" structures are linked.
23  * elt: the item for which we are searching in the hash table.
24  * result: the variable into which we'll store the element if we find it.
25  * nelems: the number of buckets in the hash table.
26  * hash_func: the hash function that operates on elements of the type of elt
27  * cmp_func: compare elements of the type of elt with those in the table (of
28  *      type "type").
29  *
30  * If the element is not in the hash table, this macro exits with result
31  * set to NULL.
32  */
33 #define HASHLOOKUP(begin, type, field, elt, r, n, hash, cmp) do {       \
34         DB_HASHTAB *__bucket;                                           \
35         u_int32_t __ndx;                                                \
36                                                                         \
37         __ndx = hash(elt) % (n);                                        \
38         __bucket = &begin[__ndx];                                       \
39         for (r = SH_TAILQ_FIRST(__bucket, type);                        \
40             r != NULL; r = SH_TAILQ_NEXT(r, field, type))               \
41                 if (cmp(elt, r))                                        \
42                         break;                                          \
43 } while(0)
44
45 /*
46  * HASHINSERT --
47  *
48  * Insert a new entry into the hash table.  This assumes that lookup has
49  * failed; don't call it if you haven't already called HASHLOOKUP.
50  * begin: the beginning address of the hash table.
51  * type: the structure type of the elements that are linked in each bucket.
52  * field: the name of the field by which the "type" structures are linked.
53  * elt: the item to be inserted.
54  * nelems: the number of buckets in the hash table.
55  * hash_func: the hash function that operates on elements of the type of elt
56  */
57 #define HASHINSERT(begin, type, field, elt, n, hash) do {               \
58         u_int32_t __ndx;                                                \
59         DB_HASHTAB *__bucket;                                           \
60                                                                         \
61         __ndx = hash(elt) % (n);                                        \
62         __bucket = &begin[__ndx];                                       \
63         SH_TAILQ_INSERT_HEAD(__bucket, elt, field, type);               \
64 } while(0)
65
66 /*
67  * HASHREMOVE --
68  *      Remove the entry with a key == elt.
69  * begin: address of the beginning of the hash table.
70  * type: the structure type of the elements that are linked in each bucket.
71  * field: the name of the field by which the "type" structures are linked.
72  * elt: the item to be deleted.
73  * nelems: the number of buckets in the hash table.
74  * hash_func: the hash function that operates on elements of the type of elt
75  * cmp_func: compare elements of the type of elt with those in the table (of
76  *      type "type").
77  */
78 #define HASHREMOVE(begin, type, field, elt, n, hash, cmp) {             \
79         u_int32_t __ndx;                                                \
80         DB_HASHTAB *__bucket;                                           \
81         SH_TAILQ_ENTRY *__entp;                                         \
82                                                                         \
83         __ndx = hash(elt) % (n);                                        \
84         __bucket = &begin[__ndx];                                       \
85         HASHLOOKUP(begin, type, field, elt, __entp, n, hash, cmp);      \
86         SH_TAILQ_REMOVE(__bucket, __entp, field, type);                 \
87 }
88
89 /*
90  * HASHREMOVE_EL --
91  *      Given the object "obj" in the table, remove it.
92  * begin: address of the beginning of the hash table.
93  * type: the structure type of the elements that are linked in each bucket.
94  * field: the name of the field by which the "type" structures are linked.
95  * obj: the object in the table that we with to delete.
96  * nelems: the number of buckets in the hash table.
97  * hash_func: the hash function that operates on elements of the type of elt
98  */
99 #define HASHREMOVE_EL(begin, type, field, obj, n, hash) {               \
100         u_int32_t __ndx;                                                \
101         DB_HASHTAB *__bucket;                                           \
102                                                                         \
103         __ndx = hash(obj) % (n);                                        \
104         __bucket = &begin[__ndx];                                       \
105         SH_TAILQ_REMOVE(__bucket, obj, field, type);                    \
106 }