/*
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 "btAlignedAllocator.h"
#include "btScalar.h" // has definitions like inline

///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...
#define BT_ALLOW_ARRAY_COPY_OPERATOR // enabling this can accidently perform deep copies of data if you are not careful

#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;

    int32_t m_size;
    int32_t m_capacity;
    T* m_data;
    //PCK: added this line
    bool m_ownsMemory;

#ifdef BT_ALLOW_ARRAY_COPY_OPERATOR
public:
    inline btAlignedObjectArray<T>& operator=(const btAlignedObjectArray<T>& other)
    {
        copyFromArray(other);
        return *this;
    }
#else //BT_ALLOW_ARRAY_COPY_OPERATOR
private:
    inline btAlignedObjectArray<T>& operator=(const btAlignedObjectArray<T>& other);
#endif //BT_ALLOW_ARRAY_COPY_OPERATOR

protected:
    inline int32_t allocSize(int32_t size)
    {
        return (size ? size * 2 : 1);
    }
    inline void copy(int32_t start, int32_t end, T* dest) const
    {
        int32_t 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
    }

    inline void init()
    {
        //PCK: added this line
        m_ownsMemory = true;
        m_data = 0;
        m_size = 0;
        m_capacity = 0;
    }
    inline void destroy(int32_t first, int32_t last)
    {
        int32_t i;
        for (i = first; i < last; i++) {
            m_data[i].~T();
        }
    }

    inline void* allocate(int32_t size)
    {
        if (size)
            return m_allocator.allocate(size);
        return 0;
    }

    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();

        int32_t otherSize = otherArray.size();
        resize(otherSize);
        otherArray.copy(0, otherSize, m_data);
    }

    /// return the number of elements in the array
    inline int32_t size() const
    {
        return m_size;
    }

    inline const T& at(int32_t n) const
    {
        btAssert(n >= 0);
        btAssert(n < size());
        return m_data[n];
    }

    inline T& at(int32_t n)
    {
        btAssert(n >= 0);
        btAssert(n < size());
        return m_data[n];
    }

    inline const T& operator[](int32_t n) const
    {
        btAssert(n >= 0);
        btAssert(n < size());
        return m_data[n];
    }

    inline T& operator[](int32_t n)
    {
        btAssert(n >= 0);
        btAssert(n < size());
        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.
    inline void clear()
    {
        destroy(0, size());

        deallocate();

        init();
    }

    inline void pop_back()
    {
        btAssert(m_size > 0);
        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.
    inline void resize(int32_t newsize, const T& fillData = T())
    {
        int32_t curSize = size();

        if (newsize < curSize) {
            for (int32_t i = newsize; i < curSize; i++) {
                m_data[i].~T();
            }
        }
        else {
            if (newsize > size()) {
                reserve(newsize);
            }
#ifdef BT_USE_PLACEMENT_NEW
            for (int32_t i = curSize; i < newsize; i++) {
                new (&m_data[i]) T(fillData);
            }
#endif //BT_USE_PLACEMENT_NEW
        }

        m_size = newsize;
    }

    inline T& expandNonInitializing()
    {
        int32_t sz = size();
        if (sz == capacity()) {
            reserve(allocSize(size()));
        }
        m_size++;

        return m_data[sz];
    }

    inline T& expand(const T& fillValue = T())
    {
        int32_t 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];
    }

    inline void push_back(const T& _Val)
    {
        int32_t 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()
    inline int32_t capacity() const
    {
        return m_capacity;
    }

    inline void reserve(int32_t _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(const L& CompareFunc, int32_t lo, int32_t hi)
    {
        //  lo is the lower index, hi is the upper index
        //  of the region of array a that is to be sorted
        int32_t 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(const 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, int32_t k, int32_t n, const 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) {
            int32_t 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(int32_t index0, int32_t 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(const L& CompareFunc)
    {
        /* sort a[0..N-1],  N.B. 0 to N-1 */
        int32_t k;
        int32_t 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
    int32_t findBinarySearch(const T& key) const
    {
        int32_t first = 0;
        int32_t last = size() - 1;

        //assume sorted array
        while (first <= last) {
            int32_t 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
    }

    int32_t findLinearSearch(const T& key) const
    {
        int32_t index = size();
        int32_t i;

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

    void remove(const T& key)
    {

        int32_t findIndex = findLinearSearch(key);
        if (findIndex < size()) {
            swap(findIndex, size() - 1);
            pop_back();
        }
    }

    //PCK: whole function
    void initializeFromBuffer(void* buffer, int32_t size, int32_t capacity)
    {
        clear();
        m_ownsMemory = false;
        m_data = (T*)buffer;
        m_size = size;
        m_capacity = capacity;
    }

    void copyFromArray(const btAlignedObjectArray& otherArray)
    {
        int32_t otherSize = otherArray.size();
        resize(otherSize);
        otherArray.copy(0, otherSize, m_data);
    }
};

#endif //BT_OBJECT_ARRAY__
