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1eb0c69c MD |
1 | #ifndef _BABELTRACE_PRIO_HEAP_H |
2 | #define _BABELTRACE_PRIO_HEAP_H | |
3 | ||
4 | /* | |
1eb0c69c MD |
5 | * Static-sized priority heap containing pointers. Based on CLRS, |
6 | * chapter 6. | |
7 | * | |
8 | * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
9 | * | |
10 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
11 | * of this software and associated documentation files (the "Software"), to deal | |
12 | * in the Software without restriction, including without limitation the rights | |
13 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
14 | * copies of the Software, and to permit persons to whom the Software is | |
15 | * furnished to do so, subject to the following conditions: | |
16 | * | |
17 | * The above copyright notice and this permission notice shall be included in | |
18 | * all copies or substantial portions of the Software. | |
c462e188 MD |
19 | * |
20 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
21 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
22 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
23 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
24 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
25 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
26 | * SOFTWARE. | |
1eb0c69c MD |
27 | */ |
28 | ||
29 | #include <unistd.h> | |
96e1cf26 | 30 | #include <babeltrace/babeltrace-internal.h> |
1eb0c69c MD |
31 | |
32 | struct ptr_heap { | |
33 | size_t len, alloc_len; | |
34 | void **ptrs; | |
35 | int (*gt)(void *a, void *b); | |
36 | }; | |
37 | ||
eacd552c MD |
38 | #ifdef DEBUG_HEAP |
39 | void check_heap(const struct ptr_heap *heap); | |
40 | #else | |
41 | static inline | |
42 | void check_heap(const struct ptr_heap *heap) | |
43 | { | |
44 | } | |
45 | #endif | |
46 | ||
1eb0c69c | 47 | /** |
dd06413f | 48 | * bt_heap_maximum - return the largest element in the heap |
1eb0c69c MD |
49 | * @heap: the heap to be operated on |
50 | * | |
51 | * Returns the largest element in the heap, without performing any modification | |
52 | * to the heap structure. Returns NULL if the heap is empty. | |
53 | */ | |
dd06413f | 54 | static inline void *bt_heap_maximum(const struct ptr_heap *heap) |
1eb0c69c | 55 | { |
eacd552c | 56 | check_heap(heap); |
96e1cf26 | 57 | return likely(heap->len) ? heap->ptrs[0] : NULL; |
1eb0c69c MD |
58 | } |
59 | ||
60 | /** | |
dd06413f | 61 | * bt_heap_init - initialize the heap |
1eb0c69c MD |
62 | * @heap: the heap to initialize |
63 | * @alloc_len: number of elements initially allocated | |
64 | * @gt: function to compare the elements | |
65 | * | |
66 | * Returns -ENOMEM if out of memory. | |
67 | */ | |
dd06413f | 68 | extern int bt_heap_init(struct ptr_heap *heap, |
1eb0c69c MD |
69 | size_t alloc_len, |
70 | int gt(void *a, void *b)); | |
71 | ||
72 | /** | |
dd06413f | 73 | * bt_heap_free - free the heap |
1eb0c69c MD |
74 | * @heap: the heap to free |
75 | */ | |
dd06413f | 76 | extern void bt_heap_free(struct ptr_heap *heap); |
1eb0c69c MD |
77 | |
78 | /** | |
dd06413f | 79 | * bt_heap_insert - insert an element into the heap |
1eb0c69c MD |
80 | * @heap: the heap to be operated on |
81 | * @p: the element to add | |
82 | * | |
83 | * Insert an element into the heap. | |
84 | * | |
85 | * Returns -ENOMEM if out of memory. | |
86 | */ | |
dd06413f | 87 | extern int bt_heap_insert(struct ptr_heap *heap, void *p); |
1eb0c69c MD |
88 | |
89 | /** | |
dd06413f | 90 | * bt_heap_remove - remove the largest element from the heap |
1eb0c69c MD |
91 | * @heap: the heap to be operated on |
92 | * | |
93 | * Returns the largest element in the heap. It removes this element from the | |
94 | * heap. Returns NULL if the heap is empty. | |
95 | */ | |
dd06413f | 96 | extern void *bt_heap_remove(struct ptr_heap *heap); |
1eb0c69c MD |
97 | |
98 | /** | |
dd06413f | 99 | * bt_heap_cherrypick - remove a given element from the heap |
1eb0c69c MD |
100 | * @heap: the heap to be operated on |
101 | * @p: the element | |
102 | * | |
103 | * Remove the given element from the heap. Return the element if present, else | |
104 | * return NULL. This algorithm has a complexity of O(n), which is higher than | |
105 | * O(log(n)) provided by the rest of this API. | |
106 | */ | |
dd06413f | 107 | extern void *bt_heap_cherrypick(struct ptr_heap *heap, void *p); |
1eb0c69c MD |
108 | |
109 | /** | |
dd06413f | 110 | * bt_heap_replace_max - replace the the largest element from the heap |
1eb0c69c MD |
111 | * @heap: the heap to be operated on |
112 | * @p: the pointer to be inserted as topmost element replacement | |
113 | * | |
114 | * Returns the largest element in the heap. It removes this element from the | |
115 | * heap. The heap is rebalanced only once after the insertion. Returns NULL if | |
116 | * the heap is empty. | |
117 | * | |
dd06413f | 118 | * This is the equivalent of calling bt_heap_remove() and then bt_heap_insert(), but |
1eb0c69c MD |
119 | * it only rebalances the heap once. It never allocates memory. |
120 | */ | |
dd06413f | 121 | extern void *bt_heap_replace_max(struct ptr_heap *heap, void *p); |
1eb0c69c | 122 | |
23a151f0 | 123 | /** |
dd06413f | 124 | * bt_heap_copy - copy a heap |
23a151f0 JD |
125 | * @dst: the destination heap (must be allocated) |
126 | * @src: the source heap | |
127 | * | |
128 | * Returns -ENOMEM if out of memory. | |
129 | */ | |
dd06413f | 130 | extern int bt_heap_copy(struct ptr_heap *dst, struct ptr_heap *src); |
23a151f0 | 131 | |
1eb0c69c | 132 | #endif /* _BABELTRACE_PRIO_HEAP_H */ |