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);
24 H->items = (xbt_heapItem_t) xbt_new0(struct xbt_heapItem, init_size);
33 * kilkil a heap and its content
35 void xbt_heap_free(xbt_heap_t H)
39 for (i = 0; i < H->count; i++)
40 H->free(H->items[i].content);
48 * @H: the heap we're working on
50 * returns the number of elements in the heap
52 int xbt_heap_size(xbt_heap_t H)
59 * @H: the heap we're working on
60 * @content: the object you want to add to the heap
61 * @key: the key associated to this object
63 * Add an element int the heap. The element with the smallest key is
64 * automatically moved at the top of the heap.
66 void xbt_heap_push(xbt_heap_t H, void *content, xbt_heap_float_t key)
68 int count = ++(H->count);
72 H->size = 2 * size + 1;
74 (void *) realloc(H->items,
75 (H->size) * sizeof(struct xbt_heapItem));
77 item = &(H->items[count - 1]);
79 item->content = content;
80 xbt_heap_increaseKey(H, count - 1);
86 * @H: the heap we're working on
88 * Extracts from the heap and returns the element with the smallest
89 * key. The element with the next smallest key is automatically moved
90 * at the top of the heap.
92 void *xbt_heap_pop(xbt_heap_t H)
96 if(H->count==0) return NULL;
100 H->items[0] = H->items[(H->count) - 1];
102 xbt_heap_maxHeapify(H);
103 if (H->count < H->size / 4 && H->size > 16) {
104 H->size = H->size / 2 + 1;
106 (void *) realloc(H->items,
107 (H->size) * sizeof(struct xbt_heapItem));
114 * @H: the heap we're working on
116 * Returns the smallest key in the heap without modifying the heap.
118 xbt_heap_float_t xbt_heap_maxkey(xbt_heap_t H)
120 if(H->count==0) abort();
125 * xbt_heap_maxcontent:
126 * @H: the heap we're working on
128 * Returns the value associated to the smallest key in the heap
129 * without modifying the heap.
131 void *xbt_heap_maxcontent(xbt_heap_t H)
133 if(H->count==0) abort();
134 return CONTENT(H, 0);
138 * xbt_heap_maxcontent:
139 * @H: the heap we're working on
141 * Restores the heap property once an element has been deleted.
143 static void xbt_heap_maxHeapify(xbt_heap_t H)
150 int count = H->count;
151 if (l < count && KEY(H, l) < KEY(H, i))
153 if (r < count && KEY(H, r) < KEY(H, greatest))
156 struct xbt_heapItem tmp = H->items[i];
157 H->items[i] = H->items[greatest];
158 H->items[greatest] = tmp;
166 * xbt_heap_maxcontent:
167 * @H: the heap we're working on
168 * @i: an item position in the heap
170 * Moves up an item at position i to its correct position. Works only
171 * when called from xbt_heap_push. Do not use otherwise.
173 static void xbt_heap_increaseKey(xbt_heap_t H, int i)
175 while (i > 0 && KEY(H, PARENT(i)) > KEY(H, i)) {
176 struct xbt_heapItem tmp = H->items[i];
177 H->items[i] = H->items[PARENT(i)];
178 H->items[PARENT(i)] = tmp;