1 #ifndef _LTTNG_PRIO_HEAP_H
2 #define _LTTNG_PRIO_HEAP_H
7 * Priority heap containing pointers. Based on CLRS, chapter 6.
9 * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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:
18 * The above copyright notice and this permission notice shall be included in
19 * all copies or substantial portions of the Software.
22 #include <linux/gfp.h>
24 struct lttng_ptr_heap
{
25 size_t len
, alloc_len
;
27 int (*gt
)(void *a
, void *b
);
32 void lttng_check_heap(const struct lttng_ptr_heap
*heap
);
35 void lttng_check_heap(const struct lttng_ptr_heap
*heap
)
41 * lttng_heap_maximum - return the largest element in the heap
42 * @heap: the heap to be operated on
44 * Returns the largest element in the heap, without performing any modification
45 * to the heap structure. Returns NULL if the heap is empty.
47 static inline void *lttng_heap_maximum(const struct lttng_ptr_heap
*heap
)
49 lttng_check_heap(heap
);
50 return heap
->len
? heap
->ptrs
[0] : NULL
;
54 * lttng_heap_init - initialize the heap
55 * @heap: the heap to initialize
56 * @alloc_len: number of elements initially allocated
57 * @gfp: allocation flags
58 * @gt: function to compare the elements
60 * Returns -ENOMEM if out of memory.
62 extern int lttng_heap_init(struct lttng_ptr_heap
*heap
,
63 size_t alloc_len
, gfp_t gfpmask
,
64 int gt(void *a
, void *b
));
67 * lttng_heap_free - free the heap
68 * @heap: the heap to free
70 extern void lttng_heap_free(struct lttng_ptr_heap
*heap
);
73 * lttng_heap_insert - insert an element into the heap
74 * @heap: the heap to be operated on
75 * @p: the element to add
77 * Insert an element into the heap.
79 * Returns -ENOMEM if out of memory.
81 extern int lttng_heap_insert(struct lttng_ptr_heap
*heap
, void *p
);
84 * lttng_heap_remove - remove the largest element from the heap
85 * @heap: the heap to be operated on
87 * Returns the largest element in the heap. It removes this element from the
88 * heap. Returns NULL if the heap is empty.
90 extern void *lttng_heap_remove(struct lttng_ptr_heap
*heap
);
93 * lttng_heap_cherrypick - remove a given element from the heap
94 * @heap: the heap to be operated on
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.
101 extern void *lttng_heap_cherrypick(struct lttng_ptr_heap
*heap
, void *p
);
104 * lttng_heap_replace_max - replace the the largest element from the heap
105 * @heap: the heap to be operated on
106 * @p: the pointer to be inserted as topmost element replacement
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
112 * This is the equivalent of calling heap_remove() and then heap_insert(), but
113 * it only rebalances the heap once. It never allocates memory.
115 extern void *lttng_heap_replace_max(struct lttng_ptr_heap
*heap
, void *p
);
117 #endif /* _LTTNG_PRIO_HEAP_H */
This page took 0.032386 seconds and 4 git commands to generate.