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"
11 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(heap,xbt,"Heap");
15 * @init_size: initial size of the heap
16 * @free_func: function to call on each element when you want to free the whole heap (or NULL if nothing to do).
20 xbt_heap_t xbt_heap_new(int init_size, void_f_pvoid_t * const free_func)
22 xbt_heap_t H = xbt_new0(struct xbt_heap, 1);
25 H->items = (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->count; i++)
41 H->free(H->items[i].content);
49 * @H: the heap we're working on
51 * returns the number of elements in the heap
53 int xbt_heap_size(xbt_heap_t H)
60 * @H: the heap we're working on
61 * @content: the object you want to add to the heap
62 * @key: the key associated to this object
64 * Add an element int the heap. The element with the smallest key is
65 * automatically moved at the top of the heap.
67 void xbt_heap_push(xbt_heap_t H, void *content, xbt_heap_float_t key)
69 int count = ++(H->count);
73 H->size = 2 * size + 1;
75 (void *) realloc(H->items,
76 (H->size) * sizeof(struct xbt_heapItem));
78 item = &(H->items[count - 1]);
80 item->content = content;
81 xbt_heap_increaseKey(H, count - 1);
87 * @H: the heap we're working on
89 * Extracts from the heap and returns the element with the smallest
90 * key. The element with the next smallest key is automatically moved
91 * at the top of the heap.
93 void *xbt_heap_pop(xbt_heap_t H)
97 if(H->count==0) return NULL;
101 H->items[0] = H->items[(H->count) - 1];
103 xbt_heap_maxHeapify(H);
104 if (H->count < H->size / 4 && H->size > 16) {
105 H->size = H->size / 2 + 1;
107 (void *) realloc(H->items,
108 (H->size) * sizeof(struct xbt_heapItem));
115 * @H: the heap we're working on
117 * Returns the smallest key in the heap without modifying the heap.
119 xbt_heap_float_t xbt_heap_maxkey(xbt_heap_t H)
121 if(H->count==0) abort();
126 * xbt_heap_maxcontent:
127 * @H: the heap we're working on
129 * Returns the value associated to the smallest key in the heap
130 * without modifying the heap.
132 void *xbt_heap_maxcontent(xbt_heap_t H)
134 if(H->count==0) abort();
135 return CONTENT(H, 0);
139 * xbt_heap_maxcontent:
140 * @H: the heap we're working on
142 * Restores the heap property once an element has been deleted.
144 static void xbt_heap_maxHeapify(xbt_heap_t H)
151 int count = H->count;
152 if (l < count && KEY(H, l) < KEY(H, i))
154 if (r < count && KEY(H, r) < KEY(H, greatest))
157 struct xbt_heapItem tmp = H->items[i];
158 H->items[i] = H->items[greatest];
159 H->items[greatest] = tmp;
167 * xbt_heap_maxcontent:
168 * @H: the heap we're working on
169 * @i: an item position in the heap
171 * Moves up an item at position i to its correct position. Works only
172 * when called from xbt_heap_push. Do not use otherwise.
174 static void xbt_heap_increaseKey(xbt_heap_t H, int i)
176 while (i > 0 && KEY(H, PARENT(i)) > KEY(H, i)) {
177 struct xbt_heapItem tmp = H->items[i];
178 H->items[i] = H->items[PARENT(i)];
179 H->items[PARENT(i)] = tmp;