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1/*
2 * Copyright (C) 2011 STRATO AG
3 * written by Arne Jansen <sensille@gmx.net>
4 * Distributed under the GNU GPL license version 2.
5 *
6 */
7
8#ifndef __ULIST__
9#define __ULIST__
10
11/*
12 * ulist is a generic data structure to hold a collection of unique u64
13 * values. The only operations it supports is adding to the list and
14 * enumerating it.
15 * It is possible to store an auxiliary value along with the key.
16 *
17 * The implementation is preliminary and can probably be sped up
18 * significantly. A first step would be to store the values in an rbtree
19 * as soon as ULIST_SIZE is exceeded.
20 */
21
22/*
23 * number of elements statically allocated inside struct ulist
24 */
25#define ULIST_SIZE 16
26
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27struct ulist_iterator {
28 int i;
29};
30
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31/*
32 * element of the list
33 */
34struct ulist_node {
35 u64 val; /* value to store */
34d73f54 36 u64 aux; /* auxiliary value saved along with the val */
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37};
38
39struct ulist {
40 /*
41 * number of elements stored in list
42 */
43 unsigned long nnodes;
44
45 /*
46 * number of nodes we already have room for
47 */
48 unsigned long nodes_alloced;
49
50 /*
51 * pointer to the array storing the elements. The first ULIST_SIZE
52 * elements are stored inline. In this case the it points to int_nodes.
53 * After exceeding ULIST_SIZE, dynamic memory is allocated.
54 */
55 struct ulist_node *nodes;
56
57 /*
58 * inline storage space for the first ULIST_SIZE entries
59 */
60 struct ulist_node int_nodes[ULIST_SIZE];
61};
62
63void ulist_init(struct ulist *ulist);
64void ulist_fini(struct ulist *ulist);
65void ulist_reinit(struct ulist *ulist);
2eec6c81 66struct ulist *ulist_alloc(gfp_t gfp_mask);
da5c8135 67void ulist_free(struct ulist *ulist);
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68int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
69int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
70 u64 *old_aux, gfp_t gfp_mask);
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71struct ulist_node *ulist_next(struct ulist *ulist,
72 struct ulist_iterator *uiter);
73
74#define ULIST_ITER_INIT(uiter) ((uiter)->i = 0)
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75
76#endif