(svn r6601) - Codechange: Support cargo subtypes in the refit window. The refit window has been altered to support resizing and scrolling. Note that the cargo subtype isn't yet passed for actual refitting yet. (Based on mart3p's patch)
/* $Id$ */
#ifndef BINARYHEAP_HPP
#define BINARYHEAP_HPP
//void* operator new (size_t size, void* p) {return p;}
#if defined(_MSC_VER) && (_MSC_VER >= 1400)
//void operator delete (void* p, void* p2) {}
#endif
/**
* Binary Heap as C++ template.
*
* For information about Binary Heap algotithm,
* see: http://www.policyalmanac.org/games/binaryHeaps.htm
*
* Implementation specific notes:
*
* 1) It allocates space for item pointers (array). Items are allocated elsewhere.
*
* 2) ItemPtr [0] is never used. Total array size is max_items + 1, because we
* use indices 1..max_items instead of zero based C indexing.
*
* 3) Item of the binary heap should support these public members:
* - 'lower-then' operator '<' - used for comparing items before moving
*
*/
template <class Titem_>
class CBinaryHeapT {
public:
typedef Titem_ *ItemPtr;
private:
int m_size; ///< Number of items in the heap
int m_max_size; ///< Maximum number of items the heap can hold
ItemPtr* m_items; ///< The heap item pointers
public:
explicit CBinaryHeapT(int max_items = 102400)
: m_size(0)
, m_max_size(max_items)
{
m_items = new ItemPtr[max_items + 1];
}
~CBinaryHeapT()
{
Clear();
delete [] m_items;
m_items = NULL;
}
public:
/** Return the number of items stored in the priority queue.
* @return number of items in the queue */
FORCEINLINE int Size() const {return m_size;};
/** Test if the priority queue is empty.
* @return true if empty */
FORCEINLINE bool IsEmpty() const {return (m_size == 0);};
/** Test if the priority queue is full.
* @return true if full. */
FORCEINLINE bool IsFull() const {return (m_size >= m_max_size);};
/** Find the smallest item in the priority queue.
* Return the smallest item, or throw assert if empty. */
FORCEINLINE Titem_& GetHead() {assert(!IsEmpty()); return *m_items[1];}
/** Insert new item into the priority queue, maintaining heap order.
* @return false if the queue is full. */
bool Push(Titem_& new_item);
/** Remove and return the smallest item from the priority queue. */
FORCEINLINE Titem_& PopHead() {Titem_& ret = GetHead(); RemoveHead(); return ret;};
/** Remove the smallest item from the priority queue. */
void RemoveHead();
/** Remove item specified by index */
void RemoveByIdx(int idx);
/** return index of the item that matches (using &item1 == &item2) the given item. */
int FindLinear(const Titem_& item) const;
/** Make the priority queue empty.
* All remaining items will remain untouched. */
void Clear() {m_size = 0;};
/** verifies the heap consistency (added during first YAPF debug phase) */
void CheckConsistency();
};
template <class Titem_>
FORCEINLINE bool CBinaryHeapT<Titem_>::Push(Titem_& new_item)
{
if (IsFull()) return false;
// make place for new item
int gap = ++m_size;
// Heapify up
for (int parent = gap / 2; (parent > 0) && (new_item < *m_items[parent]); gap = parent, parent /= 2)
m_items[gap] = m_items[parent];
m_items[gap] = &new_item;
CheckConsistency();
return true;
}
template <class Titem_>
FORCEINLINE void CBinaryHeapT<Titem_>::RemoveHead()
{
assert(!IsEmpty());
// at index 1 we have a gap now
int gap = 1;
// Heapify down:
// last item becomes a candidate for the head. Call it new_item.
Titem_& new_item = *m_items[m_size--];
// now we must maintain relation between parent and its children:
// parent <= any child
// from head down to the tail
int child = 2; // first child is at [parent * 2]
// while children are valid
while (child <= m_size) {
// choose the smaller child
if (child < m_size && *m_items[child + 1] < *m_items[child])
child++;
// is it smaller than our parent?
if (!(*m_items[child] < new_item)) {
// the smaller child is still bigger or same as parent => we are done
break;
}
// if smaller child is smaller than parent, it will become new parent
m_items[gap] = m_items[child];
gap = child;
// where do we have our new children?
child = gap * 2;
}
// move last item to the proper place
if (m_size > 0) m_items[gap] = &new_item;
CheckConsistency();
}
template <class Titem_>
inline void CBinaryHeapT<Titem_>::RemoveByIdx(int idx)
{
// at position idx we have a gap now
int gap = idx;
Titem_& last = *m_items[m_size];
if (idx < m_size) {
assert(idx >= 1);
m_size--;
// and the candidate item for fixing this gap is our last item 'last'
// Move gap / last item up:
while (gap > 1)
{
// compare [gap] with its parent
int parent = gap / 2;
if (last < *m_items[parent]) {
m_items[gap] = m_items[parent];
gap = parent;
} else {
// we don't need to continue upstairs
break;
}
}
// Heapify (move gap) down:
while (true) {
// where we do have our children?
int child = gap * 2; // first child is at [parent * 2]
if (child > m_size) break;
// choose the smaller child
if (child < m_size && *m_items[child + 1] < *m_items[child])
child++;
// is it smaller than our parent?
if (!(*m_items[child] < last)) {
// the smaller child is still bigger or same as parent => we are done
break;
}
// if smaller child is smaller than parent, it will become new parent
m_items[gap] = m_items[child];
gap = child;
}
// move parent to the proper place
if (m_size > 0) m_items[gap] = &last;
}
else {
assert(idx == m_size);
m_size--;
}
CheckConsistency();
}
template <class Titem_>
inline int CBinaryHeapT<Titem_>::FindLinear(const Titem_& item) const
{
if (IsEmpty()) return 0;
for (ItemPtr *ppI = m_items + 1, *ppLast = ppI + m_size; ppI <= ppLast; ppI++) {
if (*ppI == &item) {
return ppI - m_items;
}
}
return 0;
}
template <class Titem_>
FORCEINLINE void CBinaryHeapT<Titem_>::CheckConsistency()
{
// enable it if you suspect binary heap doesn't work well
#if 0
for (int child = 2; child <= m_size; child++) {
int parent = child / 2;
assert(!(m_items[child] < m_items[parent]));
}
#endif
}
#endif /* BINARYHEAP_HPP */