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Paul Menage8707d8b2007-10-18 23:40:22 -07001#ifndef _LINUX_PRIO_HEAP_H
2#define _LINUX_PRIO_HEAP_H
3
4/*
5 * Simple insertion-only static-sized priority heap containing
6 * pointers, based on CLR, chapter 7
7 */
8
9#include <linux/gfp.h>
10
11/**
12 * struct ptr_heap - simple static-sized priority heap
13 * @ptrs - pointer to data area
14 * @max - max number of elements that can be stored in @ptrs
15 * @size - current number of valid elements in @ptrs (in the range 0..@size-1
16 * @gt: comparison operator, which should implement "greater than"
17 */
18struct ptr_heap {
19 void **ptrs;
20 int max;
21 int size;
22 int (*gt)(void *, void *);
23};
24
25/**
26 * heap_init - initialize an empty heap with a given memory size
27 * @heap: the heap structure to be initialized
28 * @size: amount of memory to use in bytes
29 * @gfp_mask: mask to pass to kmalloc()
30 * @gt: comparison operator, which should implement "greater than"
31 */
32extern int heap_init(struct ptr_heap *heap, size_t size, gfp_t gfp_mask,
33 int (*gt)(void *, void *));
34
35/**
36 * heap_free - release a heap's storage
37 * @heap: the heap structure whose data should be released
38 */
39void heap_free(struct ptr_heap *heap);
40
41/**
42 * heap_insert - insert a value into the heap and return any overflowed value
43 * @heap: the heap to be operated on
44 * @p: the pointer to be inserted
45 *
46 * Attempts to insert the given value into the priority heap. If the
47 * heap is full prior to the insertion, then the resulting heap will
48 * consist of the smallest @max elements of the original heap and the
49 * new element; the greatest element will be removed from the heap and
50 * returned. Note that the returned element will be the new element
51 * (i.e. no change to the heap) if the new element is greater than all
52 * elements currently in the heap.
53 */
54extern void *heap_insert(struct ptr_heap *heap, void *p);
55
56
57
58#endif /* _LINUX_PRIO_HEAP_H */