+/* a generic and efficient heap */
+
+/* Authors: Arnaud Legrand */
+
+/* This program is free software; you can redistribute it and/or modify it
+ under the terms of the license (GNU LGPL) which comes with this package. */
+
+#include "xbt_heap_private.h"
+
+/**
+ * xbt_heap_new:
+ * @init_size: initial size of the heap
+ * @free_func: function to call on each element when you want to free the whole heap (or NULL if nothing to do).
+ *
+ * Creates a new heap.
+ */
+xbt_heap_t xbt_heap_new(int init_size, void_f_pvoid_t * const free_func)
+{
+ xbt_heap_t H = calloc(1, sizeof(struct xbt_heap));
+ H->size = init_size;
+ H->count = 0;
+ H->items = (xbt_heapItem_t) calloc(init_size, sizeof(struct xbt_heapItem));
+ H->free = free;
+ return H;
+}
+
+/**
+ * xbt_heap_free:
+ * @H: poor victim
+ *
+ * kilkil a heap and its content
+ */
+void xbt_heap_free(xbt_heap_t H)
+{
+ int i ;
+ if(H->free)
+ for(i=0;i < H->size;i++)
+ H->free(H->items[i].content);
+ free(H->items);
+ free(H);
+ return;
+}
+
+/**
+ * xbt_heap_push:
+ * @H: the heap we're working on
+ * @content: the object you want to add to the heap
+ * @key: the key associated to this object
+ *
+ * Add an element int the heap. The element with the smallest key is
+ * automatically moved at the top of the heap.
+ */
+void xbt_heap_push(xbt_heap_t H, void *content, xbt_heap_float_t key)
+{
+ int count = ++(H->count);
+ int size = H->size;
+ xbt_heapItem_t item;
+ if (count > size) {
+ H->size = 2 * size + 1;
+ H->items =
+ (void *) realloc(H->items,
+ (H->size) * sizeof(struct xbt_heapItem));
+ }
+ item = &(H->items[count - 1]);
+ item->key = key;
+ item->content = content;
+ xbt_heap_increaseKey(H, count - 1);
+ return;
+}
+
+/**
+ * xbt_heap_pop:
+ * @H: the heap we're working on
+ *
+ * Extracts from the heap and returns the element with the smallest
+ * key. The element with the next smallest key is automatically moved
+ * at the top of the heap.
+ */
+void *xbt_heap_pop(xbt_heap_t H)
+{
+ void *max = CONTENT(H, 0);
+ H->items[0] = H->items[(H->count) - 1];
+ (H->count)--;
+ xbt_heap_maxHeapify(H);
+ if (H->count < H->size / 4 && H->size > 16) {
+ H->size = H->size / 2 + 1;
+ H->items =
+ (void *) realloc(H->items,
+ (H->size) * sizeof(struct xbt_heapItem));
+ }
+ return max;
+}
+
+/**
+ * xbt_heap_maxkey:
+ * @H: the heap we're working on
+ *
+ * Returns the smallest key in the heap without modifying the heap.
+ */
+xbt_heap_float_t xbt_heap_maxkey(xbt_heap_t H)
+{
+ return KEY(H, 0);
+}
+
+/**
+ * xbt_heap_maxcontent:
+ * @H: the heap we're working on
+ *
+ * Returns the value associated to the smallest key in the heap
+ * without modifying the heap.
+ */
+void *xbt_heap_maxcontent(xbt_heap_t H)
+{
+ return CONTENT(H, 0);
+}
+
+/**
+ * xbt_heap_maxcontent:
+ * @H: the heap we're working on
+ *
+ * Restores the heap property once an element has been deleted.
+ */
+void xbt_heap_maxHeapify(xbt_heap_t H)
+{
+ int i=0;
+ while(1) {
+ int greatest = i;
+ int l = LEFT(i);
+ int r = RIGHT(i);
+ int count = H->count;
+ if (l < count && KEY(H, l) < KEY(H, i))
+ greatest = l;
+ if (r < count && KEY(H, r) < KEY(H, greatest))
+ greatest = r;
+ if (greatest != i) {
+ struct xbt_heapItem tmp = H->items[i];
+ H->items[i] = H->items[greatest];
+ H->items[greatest] = tmp;
+ i=greatest;
+ } else return;
+ }
+}
+
+/**
+ * xbt_heap_maxcontent:
+ * @H: the heap we're working on
+ * @i: an item position in the heap
+ *
+ * Moves up an item at position i to its correct position. Works only
+ * when called from xbt_heap_push. Do not use otherwise.
+ */
+void xbt_heap_increaseKey(xbt_heap_t H, int i)
+{
+ while (i > 0 && KEY(H, PARENT(i)) > KEY(H, i)) {
+ struct xbt_heapItem tmp = H->items[i];
+ H->items[i] = H->items[PARENT(i)];
+ H->items[PARENT(i)] = tmp;
+ i = PARENT(i);
+ }
+ return;
+}