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 "heap_private.h"
12 * @init_size: initial size of the heap
13 * @free_func: function to call on each element when you want to free the whole heap (or NULL if nothing to do).
17 xbt_heap_t xbt_heap_new(int init_size, void_f_pvoid_t * const free_func)
19 xbt_heap_t H = calloc(1, sizeof(struct xbt_heap));
23 (xbt_heapItem_t) calloc(init_size, sizeof(struct xbt_heapItem));
32 * kilkil a heap and its content
34 void xbt_heap_free(xbt_heap_t H)
38 for (i = 0; i < H->size; i++)
39 H->free(H->items[i].content);
47 * @H: the heap we're working on
48 * @content: the object you want to add to the heap
49 * @key: the key associated to this object
51 * Add an element int the heap. The element with the smallest key is
52 * automatically moved at the top of the heap.
54 void xbt_heap_push(xbt_heap_t H, void *content, xbt_heap_float_t key)
56 int count = ++(H->count);
60 H->size = 2 * size + 1;
62 (void *) realloc(H->items,
63 (H->size) * sizeof(struct xbt_heapItem));
65 item = &(H->items[count - 1]);
67 item->content = content;
68 xbt_heap_increaseKey(H, count - 1);
74 * @H: the heap we're working on
76 * Extracts from the heap and returns the element with the smallest
77 * key. The element with the next smallest key is automatically moved
78 * at the top of the heap.
80 void *xbt_heap_pop(xbt_heap_t H)
82 void *max = CONTENT(H, 0);
83 H->items[0] = H->items[(H->count) - 1];
85 xbt_heap_maxHeapify(H);
86 if (H->count < H->size / 4 && H->size > 16) {
87 H->size = H->size / 2 + 1;
89 (void *) realloc(H->items,
90 (H->size) * sizeof(struct xbt_heapItem));
97 * @H: the heap we're working on
99 * Returns the smallest key in the heap without modifying the heap.
101 xbt_heap_float_t xbt_heap_maxkey(xbt_heap_t H)
107 * xbt_heap_maxcontent:
108 * @H: the heap we're working on
110 * Returns the value associated to the smallest key in the heap
111 * without modifying the heap.
113 void *xbt_heap_maxcontent(xbt_heap_t H)
115 return CONTENT(H, 0);
119 * xbt_heap_maxcontent:
120 * @H: the heap we're working on
122 * Restores the heap property once an element has been deleted.
124 static void xbt_heap_maxHeapify(xbt_heap_t H)
131 int count = H->count;
132 if (l < count && KEY(H, l) < KEY(H, i))
134 if (r < count && KEY(H, r) < KEY(H, greatest))
137 struct xbt_heapItem tmp = H->items[i];
138 H->items[i] = H->items[greatest];
139 H->items[greatest] = tmp;
147 * xbt_heap_maxcontent:
148 * @H: the heap we're working on
149 * @i: an item position in the heap
151 * Moves up an item at position i to its correct position. Works only
152 * when called from xbt_heap_push. Do not use otherwise.
154 static void xbt_heap_increaseKey(xbt_heap_t H, int i)
156 while (i > 0 && KEY(H, PARENT(i)) > KEY(H, i)) {
157 struct xbt_heapItem tmp = H->items[i];
158 H->items[i] = H->items[PARENT(i)];
159 H->items[PARENT(i)] = tmp;