LXR linux/include/linux/prio

   1#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 */
  59