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));
104 * @brief Extracts from the heap and returns the element with the smallest key.
105 * \param H the heap we're working on
106 * \return the element with the smallest key
108 * Extracts from the heap and returns the element with the smallest key. The element with the next smallest key is
109 * automatically moved at the top of the heap.
111 void *xbt_heap_pop(xbt_heap_t H)
113 xbt_heap_item_t items = H->items;
120 XBT_DEBUG("Heap has %d elements before extraction and max elem was %g",xbt_heap_size(H),xbt_heap_maxkey(H));
124 items[0] = items[(H->count) - 1];
126 xbt_heap_max_heapify(H,0);
127 if (H->count < size >> 2 && size > 16) {
128 size = (size >> 1) + 1;
129 H->items = (void *) xbt_realloc(items, size * sizeof(struct xbt_heap_item));
133 if (H->update_callback)
134 H->update_callback(max, -1);
139 * @brief Extracts from the heap and returns the element at position i.
140 * \param H the heap we're working on
141 * \param i element position
142 * \return the element at position i if ok, NULL otherwise
144 * Extracts from the heap and returns the element at position i. The heap is automatically reordered.
146 void *xbt_heap_remove(xbt_heap_t H, int i)
148 XBT_DEBUG("Heap has %d elements: extracting element %d",xbt_heap_size(H),i);
150 if ((i < 0) || (i > H->count - 1))
152 /* put element i at head */
154 KEY(H, i) = MIN_KEY_VALUE;
155 xbt_heap_increase_key(H, i);
158 return xbt_heap_pop(H);
160 /** @brief Remove an arbitrary element from the heap
161 * @param H the heap we're working on
162 * @param content the object you want to add to the heap
163 * @param key the key associated to this object
165 void xbt_heap_rm_elm(xbt_heap_t H, void *content, double key) {
167 while (i < H->count && (KEY(H, i) != key || CONTENT(H, i) != content))
171 xbt_heap_remove(H,i);
175 * @brief Updates an element of the heap with a new value.
176 * \param H the heap we're working on
177 * \param i element position
178 * \param key new value for the element
180 * Updates an element of the heap with a new value.
182 void xbt_heap_update(xbt_heap_t H, int i, double key)
184 XBT_DEBUG("Heap has %d elements: updating element %d : was %1.12f to %1.12f ",xbt_heap_size(H),i,KEY(H, i), key);
186 if ((i < 0) || (i > H->count - 1) || key == KEY(H, i))
191 xbt_heap_increase_key(H, i);
194 xbt_heap_max_heapify(H,i);
199 * @brief returns the smallest key in the heap (heap unchanged)
200 * \param H the heap we're working on
202 * \return the smallest key in the heap without modifying the heap.
204 inline double xbt_heap_maxkey(xbt_heap_t H)
206 xbt_assert(H->count != 0, "Empty heap");
211 * @brief returns the value associated to the smallest key in the heap (heap unchanged)
212 * \param H the heap we're working on
214 * \return the value associated to the smallest key in the heap
215 * without modifying the heap.
217 void *xbt_heap_maxcontent(xbt_heap_t H)
219 xbt_assert(H->count != 0, "Empty heap");
220 return CONTENT(H, 0);
224 * \param H the heap we're working on
226 * Restores the heap property once an element has been deleted.
228 static void xbt_heap_max_heapify(xbt_heap_t H, int index)
231 int count = H->count;
232 xbt_heap_item_t items = H->items;
238 if (l < count && items[l].key < items[i].key)
240 if (r < count && items[r].key < items[greatest].key)
243 struct xbt_heap_item tmp = items[i];
244 items[i] = items[greatest];
245 items[greatest] = tmp;
246 if (H->update_callback)
247 H->update_callback(items[i].content, i);
250 if (H->update_callback)
251 H->update_callback(items[i].content, i);
258 * \param H the heap we're working on
259 * \param i an item position in the heap
261 * Moves up an item at position i to its correct position. Works only when called from xbt_heap_push.
262 * Do not use otherwise.
264 static void xbt_heap_increase_key(xbt_heap_t H, int i)
266 xbt_heap_item_t items = H->items;
268 while (i > 0 && items[p].key > items[i].key) {
269 struct xbt_heap_item tmp = items[i];
272 if (H->update_callback)
273 H->update_callback(items[i].content, i);
277 if (H->update_callback)
278 H->update_callback(items[i].content, i);