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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. | |
f3bc08c5 MD |
20 | */ |
21 | ||
c9891db2 MD |
22 | #include <linux/gfp.h> |
23 | ||
a88db018 | 24 | struct lttng_ptr_heap { |
7369e702 | 25 | size_t len, alloc_len; |
c9891db2 MD |
26 | void **ptrs; |
27 | int (*gt)(void *a, void *b); | |
7369e702 | 28 | gfp_t gfpmask; |
c9891db2 | 29 | }; |
f3bc08c5 | 30 | |
0b6d2ab3 | 31 | #ifdef DEBUG_HEAP |
a88db018 | 32 | void lttng_check_heap(const struct lttng_ptr_heap *heap); |
0b6d2ab3 MD |
33 | #else |
34 | static inline | |
a88db018 | 35 | void lttng_check_heap(const struct lttng_ptr_heap *heap) |
0b6d2ab3 MD |
36 | { |
37 | } | |
38 | #endif | |
39 | ||
f3bc08c5 | 40 | /** |
a88db018 | 41 | * lttng_heap_maximum - return the largest element in the heap |
f3bc08c5 MD |
42 | * @heap: the heap to be operated on |
43 | * | |
44 | * Returns the largest element in the heap, without performing any modification | |
45 | * to the heap structure. Returns NULL if the heap is empty. | |
46 | */ | |
a88db018 | 47 | static inline void *lttng_heap_maximum(const struct lttng_ptr_heap *heap) |
f3bc08c5 | 48 | { |
a88db018 | 49 | lttng_check_heap(heap); |
7369e702 | 50 | return heap->len ? heap->ptrs[0] : NULL; |
f3bc08c5 MD |
51 | } |
52 | ||
c9891db2 | 53 | /** |
a88db018 | 54 | * lttng_heap_init - initialize the heap |
c9891db2 | 55 | * @heap: the heap to initialize |
7369e702 | 56 | * @alloc_len: number of elements initially allocated |
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57 | * @gfp: allocation flags |
58 | * @gt: function to compare the elements | |
59 | * | |
60 | * Returns -ENOMEM if out of memory. | |
61 | */ | |
a88db018 | 62 | extern int lttng_heap_init(struct lttng_ptr_heap *heap, |
7369e702 MD |
63 | size_t alloc_len, gfp_t gfpmask, |
64 | int gt(void *a, void *b)); | |
c9891db2 MD |
65 | |
66 | /** | |
a88db018 | 67 | * lttng_heap_free - free the heap |
c9891db2 MD |
68 | * @heap: the heap to free |
69 | */ | |
a88db018 | 70 | extern void lttng_heap_free(struct lttng_ptr_heap *heap); |
c9891db2 MD |
71 | |
72 | /** | |
a88db018 | 73 | * lttng_heap_insert - insert an element into the heap |
c9891db2 | 74 | * @heap: the heap to be operated on |
7369e702 | 75 | * @p: the element to add |
c9891db2 | 76 | * |
7369e702 MD |
77 | * Insert an element into the heap. |
78 | * | |
79 | * Returns -ENOMEM if out of memory. | |
c9891db2 | 80 | */ |
a88db018 | 81 | extern int lttng_heap_insert(struct lttng_ptr_heap *heap, void *p); |
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82 | |
83 | /** | |
a88db018 | 84 | * lttng_heap_remove - remove the largest element from the heap |
f3bc08c5 MD |
85 | * @heap: the heap to be operated on |
86 | * | |
87 | * Returns the largest element in the heap. It removes this element from the | |
88 | * heap. Returns NULL if the heap is empty. | |
89 | */ | |
a88db018 | 90 | extern void *lttng_heap_remove(struct lttng_ptr_heap *heap); |
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91 | |
92 | /** | |
a88db018 | 93 | * lttng_heap_cherrypick - remove a given element from the heap |
f3bc08c5 MD |
94 | * @heap: the heap to be operated on |
95 | * @p: the element | |
96 | * | |
97 | * Remove the given element from the heap. Return the element if present, else | |
98 | * return NULL. This algorithm has a complexity of O(n), which is higher than | |
99 | * O(log(n)) provided by the rest of this API. | |
100 | */ | |
a88db018 | 101 | extern void *lttng_heap_cherrypick(struct lttng_ptr_heap *heap, void *p); |
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102 | |
103 | /** | |
a88db018 | 104 | * lttng_heap_replace_max - replace the the largest element from the heap |
f3bc08c5 MD |
105 | * @heap: the heap to be operated on |
106 | * @p: the pointer to be inserted as topmost element replacement | |
107 | * | |
108 | * Returns the largest element in the heap. It removes this element from the | |
109 | * heap. The heap is rebalanced only once after the insertion. Returns NULL if | |
110 | * the heap is empty. | |
111 | * | |
112 | * This is the equivalent of calling heap_remove() and then heap_insert(), but | |
7369e702 | 113 | * it only rebalances the heap once. It never allocates memory. |
f3bc08c5 | 114 | */ |
a88db018 | 115 | extern void *lttng_heap_replace_max(struct lttng_ptr_heap *heap, void *p); |
f3bc08c5 | 116 | |
162769ef | 117 | #endif /* _LTTNG_PRIO_HEAP_H */ |