// Copyright (C) 2002-2005 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine" and the "irrXML" project.
// For conditions of distribution and use, see copyright notice in irrlicht.h and irrXML.h

#ifndef __IRR_ARRAY_H_INCLUDED__
#define __IRR_ARRAY_H_INCLUDED__

#include "irrTypes.h"
#include "heapsort.h"

namespace irr
{
namespace core
{

//!	Self reallocating template array (like stl vector) with additional features.
/** Some features are: Heap sorting, binary search methods, easier debugging.
*/
template <class T>
class array
{

public:

	array()
 : data(0), used(0), allocated(0),
 	free_when_destroyed(true), is_sorted(true)
	{
	}

	//! Constructs a array and allocates an initial chunk of memory.
	//! \param start_count: Amount of elements to allocate.
	array(u32 start_count)
 : data(0), used(0), allocated(0),
 	free_when_destroyed(true),	is_sorted(true)
	{
 reallocate(start_count);
	}


	//! Copy constructor
	array(const array<T>& other)
 : data(0)
	{
 *this = other;
	}



	//! Destructor. Frees allocated memory, if set_free_when_destroyed
	//! was not set to false by the user before.
	~array()
	{
 if (free_when_destroyed)
 	delete [] data;
	}



	//! Reallocates the array, make it bigger or smaller.
	//! \param new_size: New size of array.
	void reallocate(u32 new_size)
	{
 T* old_data = data;

 data = new T[new_size];
 allocated = new_size;
 
 s32 end = used < new_size ? used : new_size;
 for (s32 i=0; i<end; ++i)
 	data[i] = old_data[i];

 if (allocated < used)
 	used = allocated;
 
 delete [] old_data;
	}

	//! Adds an element at back of array. If the array is to small to 
	//! add this new element, the array is made bigger.
	//! \param element: Element to add at the back of the array.
	void push_back(const T& element)
	{
 if (used + 1 > allocated)
 {
 	// reallocate(used * 2 +1);
 	// this doesn't work if the element is in the same array. So
 	// we'll copy the element first to be sure we'll get no data
 	// corruption

 	T e;
 	e = element;      // copy element
 	reallocate(used * 2 +1); // increase data block
 	data[used++] = e;    // push_back
 	is_sorted = false; 
 	return;
 }

 data[used++] = element;
 is_sorted = false;
	}


	//! Adds an element at the front of the array. If the array is to small to 
	//! add this new element, the array is made bigger. Please note that this
	//! is slow, because the whole array needs to be copied for this.
	//! \param element: Element to add at the back of the array.
	void push_front(const T& element)
	{
 if (used + 1 > allocated)
 	reallocate(used * 2 +1);

 for (int i=(int)used; i>0; --i)
 	data[i] = data[i-1];

 data[0] = element;
 is_sorted = false;
 ++used;
	}

	
	//! Insert item into array at specified position. Please use this
	//! only if you know what you are doing (possible performance loss). 
	//! The preferred method of adding elements should be push_back().
	//! \param element: Element to be inserted
	//! \param index: Where position to insert the new element.
	void insert(const T& element, u32 index=0) 
	{
 _IRR_DEBUG_BREAK_IF(index>used) // access violation

 if (used + 1 > allocated)
 	reallocate(used * 2 +1);

 for (u32 i=used++; i>index; i--) 
 	data[i] = data[i-1];

 data[index] = element;
 is_sorted = false;
	}




	//! Clears the array and deletes all allocated memory.
	void clear()
	{
 delete [] data;
 data = 0;
 used = 0;
 allocated = 0;
 is_sorted = true;
	}



	//! Sets pointer to new array, using this as new workspace.
	//! \param newPointer: Pointer to new array of elements.
	//! \param size: Size of the new array.
	void set_pointer(T* newPointer, u32 size)
	{
 delete [] data;
 data = newPointer;
 allocated = size;
 used = size;
 is_sorted = false;
	}



	//! Sets if the array should delete the memory it used.
	//! \param f: If true, the array frees the allocated memory in its
	//! destructor, otherwise not. The default is true.
	void set_free_when_destroyed(bool f)
	{
 free_when_destroyed = f;
	}



	//! Sets the size of the array.
	//! \param usedNow: Amount of elements now used.
	void set_used(u32 usedNow)
	{
 if (allocated < usedNow)
 	reallocate(usedNow);

 used = usedNow;
	}



	//! Assignement operator
	void operator=(const array<T>& other)
	{
 if (data)
 	delete [] data;

 //if (allocated < other.allocated)
 if (other.allocated == 0)
 	data = 0;
 else
 	data = new T[other.allocated];

 used = other.used;
 free_when_destroyed = other.free_when_destroyed;
 is_sorted = other.is_sorted;
 allocated = other.allocated;

 for (u32 i=0; i<other.used; ++i)
 	data[i] = other.data[i];
	}


	//! Direct access operator
	T& operator [](u32 index)
	{
 _IRR_DEBUG_BREAK_IF(index>=used) // access violation

 return data[index];
	}



	//! Direct access operator
	const T& operator [](u32 index) const
	{
 _IRR_DEBUG_BREAK_IF(index>=used) // access violation

 return data[index];
	}

  //! Gets last frame
	const T& getLast() const
	{
 _IRR_DEBUG_BREAK_IF(!used) // access violation

 return data[used-1];
	}

  //! Gets last frame
	T& getLast()
	{
 _IRR_DEBUG_BREAK_IF(!used) // access violation

 return data[used-1];
	}
  

	//! Returns a pointer to the array.
	//! \return Pointer to the array.
	T* pointer()
	{
 return data;
	}



	//! Returns a const pointer to the array.
	//! \return Pointer to the array.
	const T* const_pointer() const
	{
 return data;
	}



	//! Returns size of used array.
	//! \return Size of elements in the array.
	u32 size() const
	{
 return used;
	}



	//! Returns amount memory allocated.
	//! \return Returns amount of memory allocated. The amount of bytes
	//! allocated would be allocated_size() * sizeof(ElementsUsed);
	u32 allocated_size() const
	{
 return allocated;
	}



	//! Returns true if array is empty
	//! \return True if the array is empty, false if not.
	bool empty() const
	{
 return used == 0;
	}



	//! Sorts the array using heapsort. There is no additional memory waste and
	//! the algorithm performs (O) n log n in worst case.
	void sort()
	{
 if (is_sorted || used<2)
 	return;

 heapsort(data, used);
 is_sorted = true;
	}



	//! Performs a binary search for an element, returns -1 if not found.
	//! The array will be sorted before the binary search if it is not
	//! already sorted.
	//! \param element: Element to search for.
	//! \return Returns position of the searched element if it was found,
	//! otherwise -1 is returned.
	s32 binary_search(const T& element)
	{
 return binary_search(element, 0, used-1);
	}



	//! Performs a binary search for an element, returns -1 if not found.
	//! The array will be sorted before the binary search if it is not
	//! already sorted.
	//! \param element: Element to search for.
	//! \param left: First left index
	//! \param right: Last right index.
	//! \return Returns position of the searched element if it was found,
	//! otherwise -1 is returned.
	s32 binary_search(const T& element, s32 left, s32 right)
	{
 if (!used)
 	return -1;

 sort();

 s32 m;

 do
 {
 	m = (left+right)>>1;

 	if (element < data[m])
  right = m - 1;
 	else
  left = m + 1;

 } while((element < data[m] || data[m] < element) && left<=right);

 // this last line equals to:
 // " while((element != array[m]) && left<=right);"
 // but we only want to use the '<' operator.
 // the same in next line, it is "(element == array[m])"

 if (!(element < data[m]) && !(data[m] < element))
 	return m;

 return -1;
	}


	//! Finds an element in linear time, which is very slow. Use
	//! binary_search for faster finding. Only works if =operator is implemented.
	//! \param element: Element to search for.
	//! \return Returns position of the searched element if it was found,
	//! otherwise -1 is returned.
	s32 linear_search(T& element)
	{
 for (u32 i=0; i<used; ++i)
 	if (!(element < data[i]) && !(data[i] < element))
  return (s32)i;

 return -1;
	}


	//! Finds an element in linear time, which is very slow. Use
	//! binary_search for faster finding. Only works if =operator is implemented.
	//! \param element: Element to search for.
	//! \return Returns position of the searched element if it was found,
	//! otherwise -1 is returned.
	s32 linear_reverse_search(T& element)
	{
 for (s32 i=used-1; i>=0; --i)
 	if (data[i] == element)
  return (s32)i;

 return -1;
	}



	//! Erases an element from the array. May be slow, because all elements 
	//! following after the erased element have to be copied.
	//! \param index: Index of element to be erased.
	void erase(u32 index)
	{
 _IRR_DEBUG_BREAK_IF(index>=used || index<0) // access violation

 for (u32 i=index+1; i<used; ++i)
 	data[i-1] = data[i];

 --used;
	}


	//! Erases some elements from the array. may be slow, because all elements 
	//! following after the erased element have to be copied.
	//! \param index: Index of the first element to be erased.
	//! \param count: Amount of elements to be erased.
	void erase(u32 index, s32 count)
	{
 _IRR_DEBUG_BREAK_IF(index>=used || index<0 || count<1 || index+count>used) // access violation

 for (u32 i=index+count; i<used; ++i)
 	data[i-count] = data[i];

 used-= count;
	}


	//! Sets if the array is sorted
	void set_sorted(bool _is_sorted)
	{
 is_sorted = _is_sorted;
	}

 	
	private:

 T* data;
 u32 allocated;
 u32 used;
 bool free_when_destroyed;
 bool is_sorted;
};


} // end namespace core
} // end namespace irr



#endif