#ifndef GSL_VECTOR_ADAPTOR_HPP_INCLUDED
#define GSL_VECTOR_ADAPTOR_HPP_INCLUDED

#include <gsl/gsl_vector.h>
#include <boost/range.hpp>

#include <boost/iterator/iterator_facade.hpp>



class gsl_vector_iterator
: public boost::iterator_facade< gsl_vector_iterator , double , boost::forward_traversal_tag >
{
public :

	gsl_vector_iterator( void ): m_p(0) , m_stride( 0 ) { }
	explicit gsl_vector_iterator( gsl_vector *p ) : m_p( p->data ) , m_stride( p->stride ) { }

private :

	friend class boost::iterator_core_access;
	friend gsl_vector_iterator end_iterator( gsl_vector * );

	void increment( void ) { m_p += m_stride; }
	bool equal( const gsl_vector_iterator &other ) const { return this->m_p == other.m_p; }
	double& dereference( void ) const { return *m_p; }

	double *m_p;
	size_t m_stride;
};

class const_gsl_vector_iterator
: public boost::iterator_facade< const_gsl_vector_iterator , double , boost::forward_traversal_tag >
{
public :

	const_gsl_vector_iterator( void ): m_p(0) , m_stride( 0 ) { }
	explicit const_gsl_vector_iterator( const gsl_vector *p ) : m_p( p->data ) , m_stride( p->stride ) { }

private :

	friend class boost::iterator_core_access;
	friend const_gsl_vector_iterator end_iterator( const gsl_vector * );

	void increment( void ) { m_p += m_stride; }
	bool equal( const const_gsl_vector_iterator &other ) const { return this->m_p == other.m_p; }
	const double& dereference( void ) const { return *m_p; }

	const double *m_p;
	size_t m_stride;
};

gsl_vector_iterator end_iterator( gsl_vector *x )
{
	gsl_vector_iterator iter( x );
	iter.m_p += iter.m_stride * x->size;
	return iter;
}

const_gsl_vector_iterator end_iterator( const gsl_vector *x )
{
	const_gsl_vector_iterator iter( x );
	iter.m_p += iter.m_stride * x->size;
	return iter;
}

namespace boost {


template<>
struct range_iterator< gsl_vector* >
{
	typedef gsl_vector_iterator type;
};

template<>
struct range_iterator< const gsl_vector* >
{
	typedef const_gsl_vector_iterator type;
};



range_iterator< gsl_vector* >::type begin( gsl_vector* &x )
{
	return gsl_vector_iterator( x );
}

range_iterator< const gsl_vector* >::type begin( const gsl_vector* &x )
{
	return const_gsl_vector_iterator( x );
}

range_iterator< gsl_vector* >::type end( gsl_vector* &x )
{
	return end_iterator( x );
}

range_iterator< const gsl_vector* >::type end( const gsl_vector* &x )
{
	return end_iterator( x );
}


}


#endif // GSL_VECTOR_ADAPTOR_HPP_INCLUDED