1 /* a generic and efficient heap */
3 /* Copyright (c) 2004-2005, 2007-2015. The SimGrid Team.
4 * All rights reserved. */
6 /* This program is free software; you can redistribute it and/or modify it
7 * under the terms of the license (GNU LGPL) which comes with this package. */
9 #include "xbt/sysdep.h"
11 #include "heap_private.h"
14 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_heap, xbt, "Heap");
16 static void xbt_heap_max_heapify(xbt_heap_t H, int i);
17 static void xbt_heap_increase_key(xbt_heap_t H, int i);
19 /** @addtogroup XBT_heap
20 * \brief This section describes the API to generic heap with O(log(n)) access.
24 * @brief Creates a new heap.
25 * \param init_size initial size of the heap
26 * \param free_func function to call on each element when you want to free the whole heap (or NULL if nothing to do).
30 inline xbt_heap_t xbt_heap_new(int init_size, void_f_pvoid_t const free_func)
32 xbt_heap_t H = xbt_new0(struct xbt_heap, 1);
35 H->items = (xbt_heap_item_t) xbt_new0(struct xbt_heap_item, init_size);
41 * @brief Set the update callback function.
42 * @param H the heap we're working on
43 * \param update_callback function to call on each element to update its index when needed.
45 inline void xbt_heap_set_update_callback(xbt_heap_t H, void (*update_callback) (void*, int))
47 H->update_callback = update_callback;
51 * @brief kilkil a heap and its content
52 * @param H poor victim
54 void xbt_heap_free(xbt_heap_t H)
60 for (int i = 0; i < H->count; i++)
61 H->free(H->items[i].content);
67 * @brief returns the number of elements in the heap
68 * @param H the heap we're working on
69 * @return the number of elements in the heap
71 inline int xbt_heap_size(xbt_heap_t H)
77 * @brief Add an element into the heap.
78 * \param H the heap we're working on
79 * \param content the object you want to add to the heap
80 * \param key the key associated to this object
82 * The element with the smallest key is automatically moved at the top of the heap.
84 void xbt_heap_push(xbt_heap_t H, void *content, double key)
86 int count = ++(H->count);
92 H->size = (size << 1) + 1;
93 H->items = (void *) xbt_realloc(H->items, (H->size) * sizeof(struct xbt_heap_item));
96 item = &(H->items[count - 1]);
98 item->content = content;
99 xbt_heap_increase_key(H, count - 1);
100 XBT_DEBUG("Heap has now %d elements and max elem is %g",xbt_heap_size(H),xbt_heap_maxkey(H));
105 * @brief Extracts from the heap and returns the element with the smallest key.
106 * \param H the heap we're working on
107 * \return the element with the smallest key
109 * Extracts from the heap and returns the element with the smallest key. The element with the next smallest key is
110 * automatically moved at the top of the heap.
112 void *xbt_heap_pop(xbt_heap_t H)
114 xbt_heap_item_t items = H->items;
121 XBT_DEBUG("Heap has %d elements before extraction and max elem was %g",xbt_heap_size(H),xbt_heap_maxkey(H));
125 items[0] = items[(H->count) - 1];
127 xbt_heap_max_heapify(H,0);
128 if (H->count < size >> 2 && size > 16) {
129 size = (size >> 1) + 1;
130 H->items = (void *) xbt_realloc(items, size * sizeof(struct xbt_heap_item));
134 if (H->update_callback)
135 H->update_callback(max, -1);
140 * @brief Extracts from the heap and returns the element at position i.
141 * \param H the heap we're working on
142 * \param i element position
143 * \return the element at position i if ok, NULL otherwise
145 * Extracts from the heap and returns the element at position i. The heap is automatically reordered.
147 void *xbt_heap_remove(xbt_heap_t H, int i)
149 XBT_DEBUG("Heap has %d elements: extracting element %d",xbt_heap_size(H),i);
151 if ((i < 0) || (i > H->count - 1))
153 /* put element i at head */
155 KEY(H, i) = MIN_KEY_VALUE;
156 xbt_heap_increase_key(H, i);
159 return xbt_heap_pop(H);
161 /** @brief Remove an arbitrary element from the heap
162 * @param H the heap we're working on
163 * @param content the object you want to add to the heap
164 * @param key the key associated to this object
166 void xbt_heap_rm_elm(xbt_heap_t H, void *content, double key) {
168 while (i < H->count && (KEY(H, i) != key || CONTENT(H, i) != content))
172 xbt_heap_remove(H,i);
176 * @brief Updates an element of the heap with a new value.
177 * \param H the heap we're working on
178 * \param i element position
179 * \param key new value for the element
181 * Updates an element of the heap with a new value.
183 void xbt_heap_update(xbt_heap_t H, int i, double key)
185 XBT_DEBUG("Heap has %d elements: updating element %d : was %1.12f to %1.12f ",xbt_heap_size(H),i,KEY(H, i), key);
187 if ((i < 0) || (i > H->count - 1) || key == KEY(H, i))
192 xbt_heap_increase_key(H, i);
195 xbt_heap_max_heapify(H,i);
200 * @brief returns the smallest key in the heap (heap unchanged)
201 * \param H the heap we're working on
203 * \return the smallest key in the heap without modifying the heap.
205 inline double xbt_heap_maxkey(xbt_heap_t H)
207 xbt_assert(H->count != 0, "Empty heap");
212 * @brief returns the value associated to the smallest key in the heap (heap unchanged)
213 * \param H the heap we're working on
215 * \return the value associated to the smallest key in the heap
216 * without modifying the heap.
218 void *xbt_heap_maxcontent(xbt_heap_t H)
220 xbt_assert(H->count != 0, "Empty heap");
221 return CONTENT(H, 0);
225 * \param H the heap we're working on
227 * Restores the heap property once an element has been deleted.
229 static void xbt_heap_max_heapify(xbt_heap_t H, int index)
232 int count = H->count;
233 xbt_heap_item_t items = H->items;
239 if (l < count && items[l].key < items[i].key)
241 if (r < count && items[r].key < items[greatest].key)
244 struct xbt_heap_item tmp = items[i];
245 items[i] = items[greatest];
246 items[greatest] = tmp;
247 if (H->update_callback)
248 H->update_callback(items[i].content, i);
251 if (H->update_callback)
252 H->update_callback(items[i].content, i);
259 * \param H the heap we're working on
260 * \param i an item position in the heap
262 * Moves up an item at position i to its correct position. Works only when called from xbt_heap_push.
263 * Do not use otherwise.
265 static void xbt_heap_increase_key(xbt_heap_t H, int i)
267 xbt_heap_item_t items = H->items;
269 while (i > 0 && items[p].key > items[i].key) {
270 struct xbt_heap_item tmp = items[i];
273 if (H->update_callback)
274 H->update_callback(items[i].content, i);
278 if (H->update_callback)
279 H->update_callback(items[i].content, i);