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1 | #ifndef _LTTNG_PRIO_HEAP_H |
2 | #define _LTTNG_PRIO_HEAP_H | |
f3bc08c5 MD |
3 | |
4 | /* | |
a88db018 | 5 | * lttng_prio_heap.h |
162769ef | 6 | * |
7369e702 | 7 | * Priority heap containing pointers. Based on CLRS, chapter 6. |
162769ef MD |
8 | * |
9 | * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
10 | * | |
11 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
12 | * of this software and associated documentation files (the "Software"), to deal | |
13 | * in the Software without restriction, including without limitation the rights | |
14 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
15 | * copies of the Software, and to permit persons to whom the Software is | |
16 | * furnished to do so, subject to the following conditions: | |
17 | * | |
18 | * The above copyright notice and this permission notice shall be included in | |
19 | * all copies or substantial portions of the Software. | |
5fd8c00a MD |
20 | * |
21 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
22 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
23 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
24 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
25 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
26 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
27 | * SOFTWARE. | |
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28 | */ |
29 | ||
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30 | #include <linux/gfp.h> |
31 | ||
a88db018 | 32 | struct lttng_ptr_heap { |
7369e702 | 33 | size_t len, alloc_len; |
c9891db2 MD |
34 | void **ptrs; |
35 | int (*gt)(void *a, void *b); | |
7369e702 | 36 | gfp_t gfpmask; |
c9891db2 | 37 | }; |
f3bc08c5 | 38 | |
0b6d2ab3 | 39 | #ifdef DEBUG_HEAP |
a88db018 | 40 | void lttng_check_heap(const struct lttng_ptr_heap *heap); |
0b6d2ab3 MD |
41 | #else |
42 | static inline | |
a88db018 | 43 | void lttng_check_heap(const struct lttng_ptr_heap *heap) |
0b6d2ab3 MD |
44 | { |
45 | } | |
46 | #endif | |
47 | ||
f3bc08c5 | 48 | /** |
a88db018 | 49 | * lttng_heap_maximum - return the largest element in the heap |
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50 | * @heap: the heap to be operated on |
51 | * | |
52 | * Returns the largest element in the heap, without performing any modification | |
53 | * to the heap structure. Returns NULL if the heap is empty. | |
54 | */ | |
a88db018 | 55 | static inline void *lttng_heap_maximum(const struct lttng_ptr_heap *heap) |
f3bc08c5 | 56 | { |
a88db018 | 57 | lttng_check_heap(heap); |
7369e702 | 58 | return heap->len ? heap->ptrs[0] : NULL; |
f3bc08c5 MD |
59 | } |
60 | ||
c9891db2 | 61 | /** |
a88db018 | 62 | * lttng_heap_init - initialize the heap |
c9891db2 | 63 | * @heap: the heap to initialize |
7369e702 | 64 | * @alloc_len: number of elements initially allocated |
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65 | * @gfp: allocation flags |
66 | * @gt: function to compare the elements | |
67 | * | |
68 | * Returns -ENOMEM if out of memory. | |
69 | */ | |
a88db018 | 70 | extern int lttng_heap_init(struct lttng_ptr_heap *heap, |
7369e702 MD |
71 | size_t alloc_len, gfp_t gfpmask, |
72 | int gt(void *a, void *b)); | |
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73 | |
74 | /** | |
a88db018 | 75 | * lttng_heap_free - free the heap |
c9891db2 MD |
76 | * @heap: the heap to free |
77 | */ | |
a88db018 | 78 | extern void lttng_heap_free(struct lttng_ptr_heap *heap); |
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79 | |
80 | /** | |
a88db018 | 81 | * lttng_heap_insert - insert an element into the heap |
c9891db2 | 82 | * @heap: the heap to be operated on |
7369e702 | 83 | * @p: the element to add |
c9891db2 | 84 | * |
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85 | * Insert an element into the heap. |
86 | * | |
87 | * Returns -ENOMEM if out of memory. | |
c9891db2 | 88 | */ |
a88db018 | 89 | extern int lttng_heap_insert(struct lttng_ptr_heap *heap, void *p); |
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90 | |
91 | /** | |
a88db018 | 92 | * lttng_heap_remove - remove the largest element from the heap |
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93 | * @heap: the heap to be operated on |
94 | * | |
95 | * Returns the largest element in the heap. It removes this element from the | |
96 | * heap. Returns NULL if the heap is empty. | |
97 | */ | |
a88db018 | 98 | extern void *lttng_heap_remove(struct lttng_ptr_heap *heap); |
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99 | |
100 | /** | |
a88db018 | 101 | * lttng_heap_cherrypick - remove a given element from the heap |
f3bc08c5 MD |
102 | * @heap: the heap to be operated on |
103 | * @p: the element | |
104 | * | |
105 | * Remove the given element from the heap. Return the element if present, else | |
106 | * return NULL. This algorithm has a complexity of O(n), which is higher than | |
107 | * O(log(n)) provided by the rest of this API. | |
108 | */ | |
a88db018 | 109 | extern void *lttng_heap_cherrypick(struct lttng_ptr_heap *heap, void *p); |
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110 | |
111 | /** | |
a88db018 | 112 | * lttng_heap_replace_max - replace the the largest element from the heap |
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113 | * @heap: the heap to be operated on |
114 | * @p: the pointer to be inserted as topmost element replacement | |
115 | * | |
116 | * Returns the largest element in the heap. It removes this element from the | |
117 | * heap. The heap is rebalanced only once after the insertion. Returns NULL if | |
118 | * the heap is empty. | |
119 | * | |
120 | * This is the equivalent of calling heap_remove() and then heap_insert(), but | |
7369e702 | 121 | * it only rebalances the heap once. It never allocates memory. |
f3bc08c5 | 122 | */ |
a88db018 | 123 | extern void *lttng_heap_replace_max(struct lttng_ptr_heap *heap, void *p); |
f3bc08c5 | 124 | |
162769ef | 125 | #endif /* _LTTNG_PRIO_HEAP_H */ |