/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, 
including commercial applications, and to alter it and redistribute it freely, 
subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/


#ifndef BT_OBJECT_ARRAY__
#define BT_OBJECT_ARRAY__

#include "btScalar.h" // has definitions like SIMD_FORCE_INLINE
#include "btAlignedAllocator.h"

///If the platform doesn't support placement new, you can disable BT_USE_PLACEMENT_NEW
///then the btAlignedObjectArray doesn't support objects with virtual methods, and non-trivial constructors/destructors
///You can enable BT_USE_MEMCPY, then swapping elements in the array will use memcpy instead of operator=
///see discussion here: http://continuousphysics.com/Bullet/phpBB2/viewtopic.php?t=1231 and
///http://www.continuousphysics.com/Bullet/phpBB2/viewtopic.php?t=1240

#define BT_USE_PLACEMENT_NEW 1
//#define BT_USE_MEMCPY 1 //disable, because it is cumbersome to find out for each platform where memcpy is defined. It can be in <memory.h> or <string.h> or otherwise...

#ifdef BT_USE_MEMCPY
#include <memory.h>
#include <string.h>
#endif //BT_USE_MEMCPY

#ifdef BT_USE_PLACEMENT_NEW
#include <new> //for placement new
#endif //BT_USE_PLACEMENT_NEW


///The btAlignedObjectArray template class uses a subset of the stl::vector interface for its methods
///It is developed to replace stl::vector to avoid portability issues, including STL alignment issues to add SIMD/SSE data
template <typename T> 
//template <class T> 
class btAlignedObjectArray
{
	btAlignedAllocator<T , 16>	m_allocator;

	int					m_size;
	int					m_capacity;
	T*					m_data;
	//PCK: added this line
	bool				m_ownsMemory;

	protected:
		SIMD_FORCE_INLINE	int	allocSize(int size)
		{
			return (size ? size*2 : 1);
		}
		SIMD_FORCE_INLINE	void	copy(int start,int end, T* dest) const
		{
			int i;
			for (i=start;i<end;++i)
#ifdef BT_USE_PLACEMENT_NEW
				new (&dest[i]) T(m_data[i]);
#else
				dest[i] = m_data[i];
#endif //BT_USE_PLACEMENT_NEW
		}

		SIMD_FORCE_INLINE	void	init()
		{
			//PCK: added this line
			m_ownsMemory = true;
			m_data = 0;
			m_size = 0;
			m_capacity = 0;
		}
		SIMD_FORCE_INLINE	void	destroy(int first,int last)
		{
			int i;
			for (i=first; i<last;i++)
			{
				m_data[i].~T();
			}
		}

		SIMD_FORCE_INLINE	void* allocate(int size)
		{
			if (size)
				return m_allocator.allocate(size);
			return 0;
		}

		SIMD_FORCE_INLINE	void	deallocate()
		{
			if(m_data)	{
				//PCK: enclosed the deallocation in this block
				if (m_ownsMemory)
				{
					m_allocator.deallocate(m_data);
				}
				m_data = 0;
			}
		}

	
	public:
		
		btAlignedObjectArray()
		{
			init();
		}

		~btAlignedObjectArray()
		{
			clear();
		}

		///Generally it is best to avoid using the copy constructor of an btAlignedObjectArray, and use a (const) reference to the array instead.
		btAlignedObjectArray(const btAlignedObjectArray& otherArray)
		{
			init();

			int otherSize = otherArray.size();
			resize (otherSize);
			otherArray.copy(0, otherSize, m_data);
		}

		
		/// return the number of elements in the array
		SIMD_FORCE_INLINE	int size() const
		{	
			return m_size;
		}
		
		SIMD_FORCE_INLINE const T& operator[](int n) const
		{
			return m_data[n];
		}

		SIMD_FORCE_INLINE T& operator[](int n)
		{
			return m_data[n];
		}
		

		///clear the array, deallocated memory. Generally it is better to use array.resize(0), to reduce performance overhead of run-time memory (de)allocations.
		SIMD_FORCE_INLINE	void	clear()
		{
			destroy(0,size());
			
			deallocate();
			
			init();
		}

		SIMD_FORCE_INLINE	void	pop_back()
		{
			m_size--;
			m_data[m_size].~T();
		}

		///resize changes the number of elements in the array. If the new size is larger, the new elements will be constructed using the optional second argument.
		///when the new number of elements is smaller, the destructor will be called, but memory will not be freed, to reduce performance overhead of run-time memory (de)allocations.
		SIMD_FORCE_INLINE	void	resize(int newsize, const T& fillData=T())
		{
			int curSize = size();

			if (newsize < curSize)
			{
				for(int i = newsize; i < curSize; i++)
				{
					m_data[i].~T();
				}
			} else
			{
				if (newsize > size())
				{
					reserve(newsize);
				}
#ifdef BT_USE_PLACEMENT_NEW
				for (int i=curSize;i<newsize;i++)
				{
					new ( &m_data[i]) T(fillData);
				}
#endif //BT_USE_PLACEMENT_NEW

			}

			m_size = newsize;
		}
	

		SIMD_FORCE_INLINE	T&  expand( const T& fillValue=T())
		{	
			int sz = size();
			if( sz == capacity() )
			{
				reserve( allocSize(size()) );
			}
			m_size++;
#ifdef BT_USE_PLACEMENT_NEW
			new (&m_data[sz]) T(fillValue); //use the in-place new (not really allocating heap memory)
#endif

			return m_data[sz];		
		}


		SIMD_FORCE_INLINE	void push_back(const T& _Val)
		{	
			int sz = size();
			if( sz == capacity() )
			{
				reserve( allocSize(size()) );
			}
			
#ifdef BT_USE_PLACEMENT_NEW
			new ( &m_data[m_size] ) T(_Val);
#else
			m_data[size()] = _Val;			
#endif //BT_USE_PLACEMENT_NEW

			m_size++;
		}

	
		/// return the pre-allocated (reserved) elements, this is at least as large as the total number of elements,see size() and reserve()
		SIMD_FORCE_INLINE	int capacity() const
		{	
			return m_capacity;
		}
		
		SIMD_FORCE_INLINE	void reserve(int _Count)
		{	// determine new minimum length of allocated storage
			if (capacity() < _Count)
			{	// not enough room, reallocate
				T*	s = (T*)allocate(_Count);

				copy(0, size(), s);

				destroy(0,size());

				deallocate();
				
				//PCK: added this line
				m_ownsMemory = true;

				m_data = s;
				
				m_capacity = _Count;

			}
		}


		class less
		{
			public:

				bool operator() ( const T& a, const T& b )
				{
					return ( a < b );
				}
		};
	
		template <typename L>
		void quickSortInternal(L CompareFunc,int lo, int hi)
		{
		//  lo is the lower index, hi is the upper index
		//  of the region of array a that is to be sorted
			int i=lo, j=hi;
			T x=m_data[(lo+hi)/2];

			//  partition
			do
			{    
				while (CompareFunc(m_data[i],x)) 
					i++; 
				while (CompareFunc(x,m_data[j])) 
					j--;
				if (i<=j)
				{
					swap(i,j);
					i++; j--;
				}
			} while (i<=j);

			//  recursion
			if (lo<j) 
				quickSortInternal( CompareFunc, lo, j);
			if (i<hi) 
				quickSortInternal( CompareFunc, i, hi);
		}


		template <typename L>
		void quickSort(L CompareFunc)
		{
			//don't sort 0 or 1 elements
			if (size()>1)
			{
				quickSortInternal(CompareFunc,0,size()-1);
			}
		}


		///heap sort from http://www.csse.monash.edu.au/~lloyd/tildeAlgDS/Sort/Heap/
		template <typename L>
		void downHeap(T *pArr, int k, int n,L CompareFunc)
		{
			/*  PRE: a[k+1..N] is a heap */
			/* POST:  a[k..N]  is a heap */
			
			T temp = pArr[k - 1];
			/* k has child(s) */
			while (k <= n/2) 
			{
				int child = 2*k;
				
				if ((child < n) && CompareFunc(pArr[child - 1] , pArr[child]))
				{
					child++;
				}
				/* pick larger child */
				if (CompareFunc(temp , pArr[child - 1]))
				{
					/* move child up */
					pArr[k - 1] = pArr[child - 1];
					k = child;
				}
				else
				{
					break;
				}
			}
			pArr[k - 1] = temp;
		} /*downHeap*/

		void	swap(int index0,int index1)
		{
#ifdef BT_USE_MEMCPY
			char	temp[sizeof(T)];
			memcpy(temp,&m_data[index0],sizeof(T));
			memcpy(&m_data[index0],&m_data[index1],sizeof(T));
			memcpy(&m_data[index1],temp,sizeof(T));
#else
			T temp = m_data[index0];
			m_data[index0] = m_data[index1];
			m_data[index1] = temp;
#endif //BT_USE_PLACEMENT_NEW

		}

	template <typename L>
	void heapSort(L CompareFunc)
	{
		/* sort a[0..N-1],  N.B. 0 to N-1 */
		int k;
		int n = m_size;
		for (k = n/2; k > 0; k--) 
		{
			downHeap(m_data, k, n, CompareFunc);
		}

		/* a[1..N] is now a heap */
		while ( n>=1 ) 
		{
			swap(0,n-1); /* largest of a[0..n-1] */


			n = n - 1;
			/* restore a[1..i-1] heap */
			downHeap(m_data, 1, n, CompareFunc);
		} 
	}

	///non-recursive binary search, assumes sorted array
	int	findBinarySearch(const T& key) const
	{
		int first = 0;
		int last = size();

		//assume sorted array
		while (first <= last) {
			int mid = (first + last) / 2;  // compute mid point.
			if (key > m_data[mid]) 
				first = mid + 1;  // repeat search in top half.
			else if (key < m_data[mid]) 
				last = mid - 1; // repeat search in bottom half.
			else
				return mid;     // found it. return position /////
		}
		return size();    // failed to find key
	}


	int	findLinearSearch(const T& key) const
	{
		int index=size();
		int i;

		for (i=0;i<size();i++)
		{
			if (m_data[i] == key)
			{
				index = i;
				break;
			}
		}
		return index;
	}

	void	remove(const T& key)
	{

		int findIndex = findLinearSearch(key);
		if (findIndex<size())
		{
			swap( findIndex,size()-1);
			pop_back();
		}
	}

	//PCK: whole function
	void initializeFromBuffer(void *buffer, int size, int capacity)
	{
		clear();
		m_ownsMemory = false;
		m_data = (T*)buffer;
		m_size = size;
		m_capacity = capacity;
	}

};

#endif //BT_OBJECT_ARRAY__