#pragma once

#ifndef TCG_ALGORITHM_H

#define TCG_ALGORITHM_H

// tcg includes

#include "traits.h"

// STD includes

#include <functional></functional>

/*!

  \file     algorithm.h

  \brief    This file contains useful algorithms complementary to those

            in the standard \p \<algorithm\> and in \p boost::algorithm.</algorithm\>

*/

namespace tcg

{

//***************************************************************************

//    Binary find  algorithms

//***************************************************************************

/*!

  \brief    Performs a binary search for the a value in a sorted,

            random access iterators range, and returns its position.

  \return   The \a first range position whose value is \a equivalent to

            the specified one.

*/

template <typename ranit,="" t="" typename=""></typename>

RanIt binary_find(RanIt begin,	//!< Start of the sorted range.

				  RanIt end,	  //!< End of the sorted range.

				  const T &value) //!< Value to look up.

{

	RanIt it = std::lower_bound(begin, end, value);

	return (it != end && !(value < *it)) ? it : end;

}

//---------------------------------------------------------------------

/*!

  \brief    Performs a binary search for the a value in a sorted,

            random access iterators range, and returns its position.

  \return   The \a first range position whose value is \a equivalent to

            the specified one.

*/

template <typename compare="" ranit,="" t,="" typename=""></typename>

RanIt binary_find(RanIt begin,	//!< Start of the sorted range.

				  RanIt end,	  //!< End of the sorted range.

				  const T &value, //!< Value to look up.

				  Compare comp)   //!< Comparator functor sorting the range.

{

	RanIt it = std::lower_bound(begin, end, value, comp);

	return (it != end && !comp(value, *it)) ? it : end;

}

//***************************************************************************

//    Min/Max iterator range  algorithms

//***************************************************************************

/*!

  \brief    Calculates the minimal transformed element from the

            input iterators range.

  \return   The position of the minimal transform.

  \details  This function is similar to std::min_element(), but

            operating a unary transforming function on dereferenced

            objects.

            Furthermore, the minimal transformed value is cached

            during computation.

*/

template <typename comp="" forit,="" func,="" typename=""></typename>

ForIt min_transform(ForIt begin, //!< Start of the input iterators range.

					ForIt end,   //!< End of the input iterators range.

					Func func,   //!< The transforming function.

					Comp comp)   //!< The comparator object for transformed values.

{

	typedef typename tcg::function_traits<func>::ret_type ret_type;</func>

	typedef typename tcg::remove_cref<ret_type>::type value_type;</ret_type>

	if (begin == end)

		return end;

	ForIt minPos = begin;

	value_type minimum = func(*begin);

	for (; begin != end; ++begin) {

		const value_type &candidate = func(*begin);

		if (comp(candidate, minimum))

			minPos = begin, minimum = candidate;

	}

	return minPos;

}

//---------------------------------------------------------------------

/*!

  \brief    Calculates the minimal transformed element from the

            input iterators range.

  \return   The position of the minimal transform.

  \remark   This variation uses \p operator< as comparator for the

            transformed values.

*/

template <typename forit,="" func="" typename=""></typename>

ForIt min_transform(ForIt begin, //!< Start of the input iterators range.

					ForIt end,   //!< End of the input iterators range.

					Func func)   //!< The transforming function.

{

	typedef typename tcg::function_traits<func>::ret_type ret_type;</func>

	typedef typename tcg::remove_cref<ret_type>::type value_type;</ret_type>

	return min_transform(begin, end, func, std::less<value_type>());</value_type>

}

//---------------------------------------------------------------------

/*!

  \brief    Calculates the maximal transformed element from the

            input iterators range.

  \return   The position of the maximal transform.

  \sa       See min_transform() for a detailed explanation.

*/

template <typename comp="" forit,="" func,="" typename=""></typename>

ForIt max_transform(ForIt begin, //!< Start of the input iterators range.

					ForIt end,   //!< End of the input iterators range.

					Func func,   //!< The transforming function.

					Comp comp)   //!< The comparator object for transformed values.

{

	typedef typename tcg::function_traits<func>::ret_type ret_type;</func>

	typedef typename tcg::remove_cref<ret_type>::type value_type;</ret_type>

	if (begin == end)

		return end;

	ForIt maxPos = begin;

	value_type maximum = func(*begin);

	for (; begin != end; ++begin) {

		const value_type &candidate = func(*begin);

		if (comp(maximum, candidate))

			maxPos = begin, maximum = candidate;

	}

	return maxPos;

}

//---------------------------------------------------------------------

/*!

  \brief    Calculates the maximal transformed element from the

            input iterators range.

  \return   The position of the maximal transform.

  \sa       See min_transform() for a detailed explanation.

*/

template <typename forit,="" func="" typename=""></typename>

ForIt max_transform(ForIt begin, //!< Start of the input iterators range.

					ForIt end,   //!< End of the input iterators range.

					Func func)   //!< The transforming function.

{

	typedef typename tcg::function_traits<func>::ret_type ret_type;</func>

	typedef typename tcg::remove_cref<ret_type>::type value_type;</ret_type>

	return max_transform(begin, end, func, std::less<value_type>());</value_type>

}

} // namespace tcg

#endif // TCG_ALGORITHM_H