1 #ifndef _BABELTRACE_PRIO_HEAP_H
2 #define _BABELTRACE_PRIO_HEAP_H
7 * Static-sized priority heap containing pointers. Based on CLRS,
10 * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
12 * Permission is hereby granted, free of charge, to any person obtaining a copy
13 * of this software and associated documentation files (the "Software"), to deal
14 * in the Software without restriction, including without limitation the rights
15 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
16 * copies of the Software, and to permit persons to whom the Software is
17 * furnished to do so, subject to the following conditions:
19 * The above copyright notice and this permission notice shall be included in
20 * all copies or substantial portions of the Software.
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
27 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
32 #include <babeltrace/babeltrace-internal.h>
35 size_t len
, alloc_len
;
37 int (*gt
)(void *a
, void *b
);
41 void check_heap(const struct ptr_heap
*heap
);
44 void check_heap(const struct ptr_heap
*heap
)
50 * bt_heap_maximum - return the largest element in the heap
51 * @heap: the heap to be operated on
53 * Returns the largest element in the heap, without performing any modification
54 * to the heap structure. Returns NULL if the heap is empty.
56 static inline void *bt_heap_maximum(const struct ptr_heap
*heap
)
59 return likely(heap
->len
) ? heap
->ptrs
[0] : NULL
;
63 * bt_heap_init - initialize the heap
64 * @heap: the heap to initialize
65 * @alloc_len: number of elements initially allocated
66 * @gt: function to compare the elements
68 * Returns -ENOMEM if out of memory.
70 extern int bt_heap_init(struct ptr_heap
*heap
,
72 int gt(void *a
, void *b
));
75 * bt_heap_free - free the heap
76 * @heap: the heap to free
78 extern void bt_heap_free(struct ptr_heap
*heap
);
81 * bt_heap_insert - insert an element into the heap
82 * @heap: the heap to be operated on
83 * @p: the element to add
85 * Insert an element into the heap.
87 * Returns -ENOMEM if out of memory.
89 extern int bt_heap_insert(struct ptr_heap
*heap
, void *p
);
92 * bt_heap_remove - remove the largest element from the heap
93 * @heap: the heap to be operated on
95 * Returns the largest element in the heap. It removes this element from the
96 * heap. Returns NULL if the heap is empty.
98 extern void *bt_heap_remove(struct ptr_heap
*heap
);
101 * bt_heap_cherrypick - remove a given element from the heap
102 * @heap: the heap to be operated on
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.
109 extern void *bt_heap_cherrypick(struct ptr_heap
*heap
, void *p
);
112 * bt_heap_replace_max - replace the the largest element from the heap
113 * @heap: the heap to be operated on
114 * @p: the pointer to be inserted as topmost element replacement
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
120 * This is the equivalent of calling bt_heap_remove() and then bt_heap_insert(), but
121 * it only rebalances the heap once. It never allocates memory.
123 extern void *bt_heap_replace_max(struct ptr_heap
*heap
, void *p
);
126 * bt_heap_copy - copy a heap
127 * @dst: the destination heap (must be allocated)
128 * @src: the source heap
130 * Returns -ENOMEM if out of memory.
132 extern int bt_heap_copy(struct ptr_heap
*dst
, struct ptr_heap
*src
);
134 #endif /* _BABELTRACE_PRIO_HEAP_H */
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