iterator.h

#ifndef RDESTL_ITERATOR_H
#define RDESTL_ITERATOR_H

#include "rdestl_common.h"

namespace rde
{
//-----------------------------------------------------------------------------
struct input_iterator_tag {};
struct output_iterator_tag {};
struct forward_iterator_tag: public input_iterator_tag {};
struct bidirectional_iterator_tag: public forward_iterator_tag {};
struct random_access_iterator_tag: public bidirectional_iterator_tag {};

//-----------------------------------------------------------------------------
template<typename TIter>
struct iterator_traits
{
	typedef typename TIter::iterator_category iterator_category;
};

template<typename T>
struct iterator_traits<T*>
{
	typedef random_access_iterator_tag iterator_category;
};

//-----------------------------------------------------------------------------
namespace internal
{
template<typename TIter, typename TDist> RDE_FORCEINLINE
void distance(TIter first, TIter last, TDist& dist, rde::random_access_iterator_tag)
{
	dist = TDist(last - first);
}
template<typename TIter, typename TDist> RDE_FORCEINLINE
void distance(TIter first, TIter last, TDist& dist, rde::input_iterator_tag)
{
	dist = 0;
	while (first != last)
	{
		++dist;
		++first;
	}
}

template<typename TIter, typename TDist> RDE_FORCEINLINE
void advance(TIter& iter, TDist d, rde::random_access_iterator_tag)
{
	iter += d;
}
template<typename TIter, typename TDist> RDE_FORCEINLINE
void advance(TIter& iter, TDist d, rde::bidirectional_iterator_tag)
{
	if (d >= 0)
	{
		while (d--)
			++iter;
	}
	else
	{
		while (d++)
			--iter;
	}
}
template<typename TIter, typename TDist> RDE_FORCEINLINE
void advance(TIter& iter, TDist d, rde::input_iterator_tag)
{
	RDE_ASSERT(d >= 0);
	while (d--)
		++iter;
}

} // namespace internal
} // namespace rde

//-----------------------------------------------------------------------------
#endif // #ifndef RDESTL_ITERATOR_H