etl/algorithm.h

///\file

/******************************************************************************
The MIT License(MIT)

Embedded Template Library.

Copyright(c) 2014 jwellbelove

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#ifndef __ETL_ALGORITHM__
#define __ETL_ALGORITHM__

///\defgroup algorithm algorithm
/// Reverse engineered algorithms from C++ 0x11
///\ingroup utilities

#include <algorithm>
#include <iterator>
#include <utility>
#include <functional>

#include "type_traits.h"

namespace etl
{
  //***************************************************************************
  /// Finds the greatest and the smallest element in the range (begin, end).<br>
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/minmax_element"></a>
  ///\ingroup algorithm
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  std::pair<TIterator, TIterator> minmax_element(TIterator begin, TIterator end, TCompare compare)
  {
    TIterator minimum = begin;
    TIterator maximum = begin;

    while (begin != end)
    {
      if (compare(*begin, *minimum))
      {
        minimum = begin;
      }

      if (compare(*maximum, *begin))
      {
        maximum = begin;
      }
        
      ++begin;
    }

    return std::pair<TIterator, TIterator>(minimum, maximum);
  }

  //***************************************************************************
  /// minmax_element
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/minmax_element"></a>
  //***************************************************************************
  template <typename TIterator>
  std::pair<TIterator, TIterator> minmax_element(TIterator begin, TIterator end)
  {
      typedef typename std::iterator_traits<TIterator>::value_type value_t;

      return etl::minmax_element(begin, end, std::less<value_t>());
  }	
	
  //***************************************************************************
  /// minmax
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/minmax"></a>
  //***************************************************************************
  template <typename T> 
  std::pair<const T&, const T&> minmax(const T& a, const T& b)
  {
	  return (b < a) ? std::pair<const T&, const T&>(b, a) : std::pair<const T&, const T&>(a, b);
  }

  //***************************************************************************
  /// minmax
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/minmax"></a>
  //***************************************************************************
  template <typename T, typename TCompare> 
  std::pair<const T&, const T&> minmax(const T& a, const T& b, TCompare compare)
  {
    return compare(b, a) ? std::pair<const T&, const T&>(b, a) : std::pair<const T&, const T&>(a, b);
  }

  //***************************************************************************
  /// is_sorted_until
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/is_sorted_until"></a>
  //***************************************************************************
  template <typename TIterator>
  TIterator is_sorted_until(TIterator begin, TIterator end)
  {
    if (begin != end) 
    {
      TIterator next = begin;

      while (++next != end) 
      {
        if (*next < *begin)
        {
          return next;
        }
            
        ++begin;
      }
    }

    return end;
  }

  //***************************************************************************
  /// is_sorted_until
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/is_sorted_until"></a>
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  TIterator is_sorted_until(TIterator begin, TIterator end, TCompare compare) 
  {
    if (begin != end) 
    {
      TIterator next = begin;

      while (++next != end) 
      {
        if (compare(*next, *begin))
        {
          return next;
        }
            
        ++begin;
      }
    }

    return end;
  }

  //***************************************************************************
  /// is_sorted
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/is_sorted"></a>
  //***************************************************************************
  template<class TIterator>
  bool is_sorted(TIterator begin, TIterator end)
  {
    return etl::is_sorted_until(begin, end) == end;
  }

  //***************************************************************************
  /// is_sorted
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/is_sorted"></a>
  //***************************************************************************
  template<class TIterator, class TCompare>
  bool is_sorted(TIterator begin, TIterator end, TCompare compare)
  {
    return etl::is_sorted_until(begin, end, compare) == end;
  }

  //***************************************************************************
  /// copy_n
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/copy_n"></a>
  //***************************************************************************
  template <typename TInputIterator, typename Size, typename TOutputIterator>
  TOutputIterator copy_n(TInputIterator begin, Size count, TOutputIterator result)
  {
    if (count > 0)
    {
      for (Size i = 0; i < count; ++i)
      {
        *result++ = *begin++;
      }
    }

    return result;
  }

  //***************************************************************************
  /// copy_if
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/copy"></a>
  //***************************************************************************
  template <typename TIterator, typename TOutputIterator, typename TUnaryPredicate>
  TOutputIterator copy_if(TIterator begin, TIterator end, TOutputIterator out, TUnaryPredicate predicate)
  {
    while (begin != end)
    {
      if (predicate(*begin))
      {
        *out++ = *begin;
      }
         
      ++begin;
    }

    return out;
  }

  //***************************************************************************
  /// find_if_not
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/find"></a>
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate>
  TIterator find_if_not(TIterator begin, TIterator end, TUnaryPredicate predicate)
  {
    while (begin != end)
    {
      if (!predicate(*begin))
      {
        return begin;
      }

      ++begin;
    }

    return end;
  }

  //***************************************************************************
  /// all_of
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/all_any_none_of"></a>
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate >
  bool all_of(TIterator begin, TIterator end, TUnaryPredicate predicate)
  {
    return etl::find_if_not(begin, end, predicate) == end;
  }

  //***************************************************************************
  /// any_of
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/all_any_none_of"></a>
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate >
  bool any_of(TIterator begin, TIterator end, TUnaryPredicate predicate)
  {
    return std::find_if(begin, end, predicate) != end;
  }

  //***************************************************************************
  /// none_of
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/all_any_none_of"></a>
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate >
  bool none_of(TIterator begin, TIterator end, TUnaryPredicate predicate)
  {
    return std::find_if(begin, end, predicate) == end;
  }
  
  //***************************************************************************
  /// is_permutation
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/is_permutation"></a>
  //***************************************************************************
  template <typename TIterator1, typename TIterator2>
  bool is_permutation(TIterator1 begin1, TIterator1 end1, TIterator2 begin2)
  {
    if (begin1 != end1)
    {
      TIterator2 end2 = begin2;

      std::advance(end2, std::distance(begin1, end1));

      for (TIterator1 i = begin1; i != end1; ++i) 
      {
        if (i == std::find(begin1, i, *i))
        {
          size_t n = std::count(begin2, end2, *i);

          if (n == 0 || std::count(i, end1, *i) != n)
          {
            return false;
          }
        }
      }
    }

    return true;
  }
  
  //***************************************************************************
  /// is_permutation
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/is_permutation"></a>
  //***************************************************************************
  template <typename TIterator1, typename TIterator2>
  bool is_permutation(TIterator1 begin1, TIterator1 end1, TIterator2 begin2, TIterator2 end2)
  {
    if (begin1 != end1)
    {
      for (TIterator1 i = begin1; i != end1; ++i) 
      {
        if (i == std::find(begin1, i, *i))
        {
          size_t n = std::count(begin2, end2, *i);

          if (n == 0 || std::count(i, end1, *i) != n)
          {
            return false;
          }
        }
      }
    }

    return true;
  } 

  //***************************************************************************
  /// is_permutation
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/is_permutation"></a>
  //***************************************************************************
  template <typename TIterator1, typename TIterator2, typename TBinaryPredicate>
  bool is_permutation(TIterator1 begin1, TIterator1 end1, TIterator2 begin2, TBinaryPredicate predicate)
  {
    if (begin1 != end1)
    {
      TIterator2 end2 = begin2;

      std::advance(end2, std::distance(begin1, end1));

      for (TIterator1 i = begin1; i != end1; ++i) 
      {
        if (i == std::find_if(begin1, i, std::bind1st(predicate, *i)))
        {
          size_t n = std::count(begin2, end2, *i);

          if (n == 0 || std::count(i, end1, *i) != n)
          {
            return false;
          }
        }
      }
    }

    return true;
  }

  //***************************************************************************
  /// is_permutation
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/is_permutation"></a>
  //***************************************************************************
  template <typename TIterator1, typename TIterator2, typename TBinaryPredicate>
  bool is_permutation(TIterator1 begin1, TIterator1 end1, TIterator2 begin2, TIterator2 end2, TBinaryPredicate predicate)
  {
    if (begin1 != end1)
    {
      for (TIterator1 i = begin1; i != end1; ++i) 
      {
        if (i == std::find_if(begin1, i, std::bind1st(predicate, *i)))
        {
          size_t n = std::count(begin2, end2, *i);

          if (n == 0 || std::count(i, end1, *i) != n)
          {
            return false;
          }
        }
      }
    }

    return true;
  }

  //***************************************************************************
  /// is_partitioned
  ///\ingroup algorithm
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/is_partitioned"></a>
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate>
  bool is_partitioned(TIterator begin, TIterator end, TUnaryPredicate predicate)
  {
    while (begin != end)
    {
      if (!predicate(*begin++))
      {
        break;
      }
    }

    while (begin != end)
    {
      if (predicate(*begin++))
      {
        return false;
      }
    }
     
    return true;
  }

  //***************************************************************************
  /// partition_point
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/partition_point"></a>
  ///\ingroup algorithm
  //***************************************************************************
  template <class TIterator, class TUnaryPredicate>
  TIterator partition_point(TIterator begin, TIterator end, TUnaryPredicate predicate)
  {
    while (begin != end)
    {
      if (!predicate(*begin))
      {
        return begin;
      }

      ++begin;
    }

    return begin;
  }

  //***************************************************************************
  /// Copies the elements from the range (begin, end) to two different ranges
  /// depending on the value returned by the predicate.<br>
  ///<a href="http://en.cppreference.com/w/cpp/algorithm/partition_copy"></a>
  ///\ingroup algorithm
  //***************************************************************************
  template <typename TSource, typename TDestinationTrue, typename TDestinationFalse, typename TUnaryPredicate>
  std::pair<TDestinationTrue, TDestinationFalse> partition_copy(TSource           begin,
	                                                              TSource           end, 
	                                                              TDestinationTrue  destination_true,
															                                	TDestinationFalse destination_false, 
															                                	TUnaryPredicate   predicate)
  {
    while (begin != end)
    {
      if (predicate(*begin))
      {
        *destination_true++ = *begin++;
      }
      else
      {
        *destination_false++ = *begin++;
      }
    }

    return std::pair<TDestinationTrue, TDestinationFalse>(destination_true, destination_false);
  }
}

#endif