#pragma once

#ifndef TCG_PTR_WRAPPER
#define TCG_PTR_WRAPPER

// STD includes
#include <iterator>

namespace tcg
{

/*!
  \brief    The ptr_wrapper class implements the basic functions necessary
            to wrap a generic pointer object. The use case for this class
            is to allow pointer inheritance.
*/

template <typename T>
class ptr
{
public:
	typedef T *ptr_type;

	typedef typename std::iterator_traits<ptr_type>::iterator_category iterator_category;
	typedef typename std::iterator_traits<ptr_type>::value_type value_type;
	typedef typename std::iterator_traits<ptr_type>::difference_type difference_type;
	typedef typename std::iterator_traits<ptr_type>::pointer pointer;
	typedef typename std::iterator_traits<ptr_type>::reference reference;

public:
	explicit ptr(ptr_type p = ptr_type()) : m_ptr(p) {}

	operator bool() const { return m_ptr; } // There should be no need to use
											// the Safe Bool idiom
	bool operator==(const ptr &other) const { return (m_ptr == other.m_ptr); }
	bool operator!=(const ptr &other) const { return (m_ptr != other.m_ptr); }

	bool operator<(const ptr &other) const { return (m_ptr < other.m_ptr); }
	bool operator>(const ptr &other) const { return (m_ptr > other.m_ptr); }
	bool operator<=(const ptr &other) const { return (m_ptr <= other.m_ptr); }
	bool operator>=(const ptr &other) const { return (m_ptr >= other.m_ptr); }

	ptr &operator++()
	{
		++m_ptr;
		return *this;
	}
	ptr operator++(int) { return ptr(m_ptr++, *this); }

	ptr &operator--()
	{
		--m_ptr;
		return *this;
	}
	ptr operator--(int) { return ptr(m_ptr--, *this); }

	ptr operator+(difference_type d) const { return ptr(m_ptr + d, *this); }
	ptr &operator+=(difference_type d)
	{
		m_ptr += d;
		return *this;
	}

	ptr operator-(difference_type d) const { return ptr(m_ptr - d, *this); }
	ptr &operator-=(difference_type d)
	{
		m_ptr -= d;
		return *this;
	}

	difference_type operator-(const ptr &other) const { return m_ptr - other.m_ptr; }

	pointer operator->() const { return m_ptr; }
	reference operator*() const { return *m_ptr; }
	reference operator[](difference_type d) const { return m_ptr[d]; }

protected:
	ptr_type m_ptr;
};

//=======================================================

template <typename T>
ptr<T> make_ptr(T *p) { return ptr<T>(p); }

} // namespace tcg

#endif // TCG_PTR_WRAPPER