1 /* a generic and efficient heap */
3 /* Authors: Arnaud Legrand */
5 /* This program is free software; you can redistribute it and/or modify it
6 under the terms of the license (GNU LGPL) which comes with this package. */
8 #include "xbt/sysdep.h"
10 #include "heap_private.h"
14 * @init_size: initial size of the heap
15 * @free_func: function to call on each element when you want to free the whole heap (or NULL if nothing to do).
19 xbt_heap_t xbt_heap_new(int init_size, void_f_pvoid_t * const free_func)
21 xbt_heap_t H = xbt_new0(struct xbt_heap, 1);
25 (xbt_heapItem_t) xbt_new0(struct xbt_heapItem, init_size);
34 * kilkil a heap and its content
36 void xbt_heap_free(xbt_heap_t H)
40 for (i = 0; i < H->size; i++)
41 H->free(H->items[i].content);
49 * @H: the heap we're working on
50 * @content: the object you want to add to the heap
51 * @key: the key associated to this object
53 * Add an element int the heap. The element with the smallest key is
54 * automatically moved at the top of the heap.
56 void xbt_heap_push(xbt_heap_t H, void *content, xbt_heap_float_t key)
58 int count = ++(H->count);
62 H->size = 2 * size + 1;
64 (void *) realloc(H->items,
65 (H->size) * sizeof(struct xbt_heapItem));
67 item = &(H->items[count - 1]);
69 item->content = content;
70 xbt_heap_increaseKey(H, count - 1);
76 * @H: the heap we're working on
78 * Extracts from the heap and returns the element with the smallest
79 * key. The element with the next smallest key is automatically moved
80 * at the top of the heap.
82 void *xbt_heap_pop(xbt_heap_t H)
84 void *max = CONTENT(H, 0);
85 H->items[0] = H->items[(H->count) - 1];
87 xbt_heap_maxHeapify(H);
88 if (H->count < H->size / 4 && H->size > 16) {
89 H->size = H->size / 2 + 1;
91 (void *) realloc(H->items,
92 (H->size) * sizeof(struct xbt_heapItem));
99 * @H: the heap we're working on
101 * Returns the smallest key in the heap without modifying the heap.
103 xbt_heap_float_t xbt_heap_maxkey(xbt_heap_t H)
109 * xbt_heap_maxcontent:
110 * @H: the heap we're working on
112 * Returns the value associated to the smallest key in the heap
113 * without modifying the heap.
115 void *xbt_heap_maxcontent(xbt_heap_t H)
117 return CONTENT(H, 0);
121 * xbt_heap_maxcontent:
122 * @H: the heap we're working on
124 * Restores the heap property once an element has been deleted.
126 static void xbt_heap_maxHeapify(xbt_heap_t H)
133 int count = H->count;
134 if (l < count && KEY(H, l) < KEY(H, i))
136 if (r < count && KEY(H, r) < KEY(H, greatest))
139 struct xbt_heapItem tmp = H->items[i];
140 H->items[i] = H->items[greatest];
141 H->items[greatest] = tmp;
149 * xbt_heap_maxcontent:
150 * @H: the heap we're working on
151 * @i: an item position in the heap
153 * Moves up an item at position i to its correct position. Works only
154 * when called from xbt_heap_push. Do not use otherwise.
156 static void xbt_heap_increaseKey(xbt_heap_t H, int i)
158 while (i > 0 && KEY(H, PARENT(i)) > KEY(H, i)) {
159 struct xbt_heapItem tmp = H->items[i];
160 H->items[i] = H->items[PARENT(i)];
161 H->items[PARENT(i)] = tmp;