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fe59694b JR |
1 | /* |
2 | * Copyright (c) 2016 Nicira, Inc. | |
3 | * | |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); | |
5 | * you may not use this file except in compliance with the License. | |
6 | * You may obtain a copy of the License at: | |
7 | * | |
8 | * http://www.apache.org/licenses/LICENSE-2.0 | |
9 | * | |
10 | * Unless required by applicable law or agreed to in writing, software | |
11 | * distributed under the License is distributed on an "AS IS" BASIS, | |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
13 | * See the License for the specific language governing permissions and | |
14 | * limitations under the License. | |
15 | */ | |
16 | ||
17 | #include <config.h> | |
18 | ||
19 | #include "object-collection.h" | |
20 | #include "util.h" | |
21 | ||
22 | void | |
23 | object_collection_init(struct object_collection *coll) | |
24 | { | |
25 | coll->objs = coll->stub; | |
26 | coll->n = 0; | |
27 | coll->capacity = ARRAY_SIZE(coll->stub); | |
28 | } | |
29 | ||
30 | void | |
31 | object_collection_add(struct object_collection *coll, void *obj) | |
32 | { | |
33 | if (coll->n >= coll->capacity) { | |
34 | size_t old_size, new_size; | |
35 | ||
36 | old_size = coll->capacity * sizeof *coll->objs; | |
37 | coll->capacity *= 2; | |
38 | new_size = coll->capacity * sizeof *coll->objs; | |
39 | ||
40 | if (coll->objs == coll->stub) { | |
41 | coll->objs = xmalloc(new_size); | |
42 | memcpy(coll->objs, coll->stub, old_size); | |
43 | } else { | |
44 | coll->objs = xrealloc(coll->objs, new_size); | |
45 | } | |
46 | } | |
47 | ||
48 | coll->objs[coll->n++] = obj; | |
49 | } | |
50 | ||
51 | void | |
52 | object_collection_remove(struct object_collection *coll, void *obj) | |
53 | { | |
54 | size_t i; | |
55 | ||
56 | for (i = 0; i < coll->n; i++) { | |
57 | if (coll->objs[i] == obj) { | |
58 | break; | |
59 | } | |
60 | } | |
61 | if (i == coll->n) { | |
62 | return; | |
63 | } | |
64 | ||
65 | coll->n--; | |
66 | /* Swap the last item in if needed. */ | |
67 | if (i != coll->n) { | |
68 | coll->objs[i] = coll->objs[coll->n]; | |
69 | } | |
70 | ||
71 | /* Shrink? Watermark at '/ 4' to get hysteresis and leave spare | |
72 | * capacity. */ | |
73 | if (coll->objs != coll->stub && coll->n <= coll->capacity / 4) { | |
74 | size_t actual_size, new_size; | |
75 | ||
76 | actual_size = coll->n * sizeof *coll->objs; | |
77 | coll->capacity /= 2; | |
78 | new_size = coll->capacity * sizeof *coll->objs; | |
79 | ||
80 | if (new_size <= sizeof(coll->stub)) { | |
81 | memcpy(coll->stub, coll->objs, actual_size); | |
82 | free(coll->objs); | |
83 | coll->objs = coll->stub; | |
84 | } else { | |
85 | coll->objs = xrealloc(coll->objs, new_size); | |
86 | } | |
87 | } | |
88 | } | |
89 | ||
90 | void | |
91 | object_collection_move(struct object_collection *to, | |
92 | struct object_collection *from) | |
93 | { | |
94 | ovs_assert(to->n == 0); | |
95 | ||
96 | *to = *from; | |
97 | if (from->objs == from->stub) { | |
98 | to->objs = to->stub; | |
99 | } | |
100 | object_collection_init(from); | |
101 | } | |
102 | ||
103 | /* Returns a NULL-terminated array of object pointers, | |
104 | * destroys 'rules'. */ | |
105 | void * | |
106 | object_collection_detach(struct object_collection *coll) | |
107 | { | |
108 | void **array; | |
109 | ||
110 | object_collection_add(coll, NULL); | |
111 | ||
112 | if (coll->objs == coll->stub) { | |
113 | coll->objs = xmemdup(coll->objs, coll->n * sizeof *coll->objs); | |
114 | } | |
115 | ||
116 | array = coll->objs; | |
117 | object_collection_init(coll); | |
118 | ||
119 | return array; | |
120 | } | |
121 | ||
122 | void | |
123 | object_collection_destroy(struct object_collection *coll) | |
124 | { | |
125 | if (coll->objs != coll->stub) { | |
126 | free(coll->objs); | |
127 | } | |
128 | ||
129 | /* Make repeated destruction harmless. */ | |
130 | object_collection_init(coll); | |
131 | } |