boost/algorithm/cxx11/is_sorted.hpp
// Copyright (c) 2010 Nuovation System Designs, LLC
// Grant Erickson <gerickson@nuovations.com>
//
// Reworked somewhat by Marshall Clow; August 2010
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/ for latest version.
//
#ifndef BOOST_ALGORITHM_ORDERED_HPP
#define BOOST_ALGORITHM_ORDERED_HPP
#include <functional>
#include <iterator>
#include <boost/config.hpp>
#include <boost/range/begin.hpp>
#include <boost/range/end.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/type_traits/is_same.hpp>
#include <boost/type_traits/type_identity.hpp> // for boost::type_identity
namespace boost { namespace algorithm {
/// \fn is_sorted_until ( ForwardIterator first, ForwardIterator last, Pred p )
/// \return the point in the sequence [first, last) where the elements are unordered
/// (according to the comparison predicate 'p').
///
/// \param first The start of the sequence to be tested.
/// \param last One past the end of the sequence
/// \param p A binary predicate that returns true if two elements are ordered.
///
template <typename ForwardIterator, typename Pred>
BOOST_CXX14_CONSTEXPR ForwardIterator is_sorted_until ( ForwardIterator first, ForwardIterator last, Pred p )
{
if ( first == last ) return last; // the empty sequence is ordered
ForwardIterator next = first;
while ( ++next != last )
{
if ( p ( *next, *first ))
return next;
first = next;
}
return last;
}
/// \fn is_sorted_until ( ForwardIterator first, ForwardIterator last )
/// \return the point in the sequence [first, last) where the elements are unordered
///
/// \param first The start of the sequence to be tested.
/// \param last One past the end of the sequence
///
template <typename ForwardIterator>
BOOST_CXX14_CONSTEXPR ForwardIterator is_sorted_until ( ForwardIterator first, ForwardIterator last )
{
typedef typename std::iterator_traits<ForwardIterator>::value_type value_type;
return boost::algorithm::is_sorted_until ( first, last, std::less<value_type>());
}
/// \fn is_sorted ( ForwardIterator first, ForwardIterator last, Pred p )
/// \return whether or not the entire sequence is sorted
///
/// \param first The start of the sequence to be tested.
/// \param last One past the end of the sequence
/// \param p A binary predicate that returns true if two elements are ordered.
///
template <typename ForwardIterator, typename Pred>
BOOST_CXX14_CONSTEXPR bool is_sorted ( ForwardIterator first, ForwardIterator last, Pred p )
{
return boost::algorithm::is_sorted_until (first, last, p) == last;
}
/// \fn is_sorted ( ForwardIterator first, ForwardIterator last )
/// \return whether or not the entire sequence is sorted
///
/// \param first The start of the sequence to be tested.
/// \param last One past the end of the sequence
///
template <typename ForwardIterator>
BOOST_CXX14_CONSTEXPR bool is_sorted ( ForwardIterator first, ForwardIterator last )
{
return boost::algorithm::is_sorted_until (first, last) == last;
}
///
/// -- Range based versions of the C++11 functions
///
/// \fn is_sorted_until ( const R &range, Pred p )
/// \return the point in the range R where the elements are unordered
/// (according to the comparison predicate 'p').
///
/// \param range The range to be tested.
/// \param p A binary predicate that returns true if two elements are ordered.
///
template <typename R, typename Pred>
BOOST_CXX14_CONSTEXPR typename boost::lazy_disable_if_c<
boost::is_same<R, Pred>::value,
typename boost::range_iterator<const R>
>::type is_sorted_until ( const R &range, Pred p )
{
return boost::algorithm::is_sorted_until ( boost::begin ( range ), boost::end ( range ), p );
}
/// \fn is_sorted_until ( const R &range )
/// \return the point in the range R where the elements are unordered
///
/// \param range The range to be tested.
///
template <typename R>
BOOST_CXX14_CONSTEXPR typename boost::range_iterator<const R>::type is_sorted_until ( const R &range )
{
return boost::algorithm::is_sorted_until ( boost::begin ( range ), boost::end ( range ));
}
/// \fn is_sorted ( const R &range, Pred p )
/// \return whether or not the entire range R is sorted
/// (according to the comparison predicate 'p').
///
/// \param range The range to be tested.
/// \param p A binary predicate that returns true if two elements are ordered.
///
template <typename R, typename Pred>
BOOST_CXX14_CONSTEXPR typename boost::lazy_disable_if_c< boost::is_same<R, Pred>::value, boost::type_identity<bool> >::type
is_sorted ( const R &range, Pred p )
{
return boost::algorithm::is_sorted ( boost::begin ( range ), boost::end ( range ), p );
}
/// \fn is_sorted ( const R &range )
/// \return whether or not the entire range R is sorted
///
/// \param range The range to be tested.
///
template <typename R>
BOOST_CXX14_CONSTEXPR bool is_sorted ( const R &range )
{
return boost::algorithm::is_sorted ( boost::begin ( range ), boost::end ( range ));
}
///
/// -- Range based versions of the C++11 functions
///
/// \fn is_increasing ( ForwardIterator first, ForwardIterator last )
/// \return true if the entire sequence is increasing; i.e, each item is greater than or
/// equal to the previous one.
///
/// \param first The start of the sequence to be tested.
/// \param last One past the end of the sequence
///
/// \note This function will return true for sequences that contain items that compare
/// equal. If that is not what you intended, you should use is_strictly_increasing instead.
template <typename ForwardIterator>
BOOST_CXX14_CONSTEXPR bool is_increasing ( ForwardIterator first, ForwardIterator last )
{
typedef typename std::iterator_traits<ForwardIterator>::value_type value_type;
return boost::algorithm::is_sorted (first, last, std::less<value_type>());
}
/// \fn is_increasing ( const R &range )
/// \return true if the entire sequence is increasing; i.e, each item is greater than or
/// equal to the previous one.
///
/// \param range The range to be tested.
///
/// \note This function will return true for sequences that contain items that compare
/// equal. If that is not what you intended, you should use is_strictly_increasing instead.
template <typename R>
BOOST_CXX14_CONSTEXPR bool is_increasing ( const R &range )
{
return is_increasing ( boost::begin ( range ), boost::end ( range ));
}
/// \fn is_decreasing ( ForwardIterator first, ForwardIterator last )
/// \return true if the entire sequence is decreasing; i.e, each item is less than
/// or equal to the previous one.
///
/// \param first The start of the sequence to be tested.
/// \param last One past the end of the sequence
///
/// \note This function will return true for sequences that contain items that compare
/// equal. If that is not what you intended, you should use is_strictly_decreasing instead.
template <typename ForwardIterator>
BOOST_CXX14_CONSTEXPR bool is_decreasing ( ForwardIterator first, ForwardIterator last )
{
typedef typename std::iterator_traits<ForwardIterator>::value_type value_type;
return boost::algorithm::is_sorted (first, last, std::greater<value_type>());
}
/// \fn is_decreasing ( const R &range )
/// \return true if the entire sequence is decreasing; i.e, each item is less than
/// or equal to the previous one.
///
/// \param range The range to be tested.
///
/// \note This function will return true for sequences that contain items that compare
/// equal. If that is not what you intended, you should use is_strictly_decreasing instead.
template <typename R>
BOOST_CXX14_CONSTEXPR bool is_decreasing ( const R &range )
{
return is_decreasing ( boost::begin ( range ), boost::end ( range ));
}
/// \fn is_strictly_increasing ( ForwardIterator first, ForwardIterator last )
/// \return true if the entire sequence is strictly increasing; i.e, each item is greater
/// than the previous one
///
/// \param first The start of the sequence to be tested.
/// \param last One past the end of the sequence
///
/// \note This function will return false for sequences that contain items that compare
/// equal. If that is not what you intended, you should use is_increasing instead.
template <typename ForwardIterator>
BOOST_CXX14_CONSTEXPR bool is_strictly_increasing ( ForwardIterator first, ForwardIterator last )
{
typedef typename std::iterator_traits<ForwardIterator>::value_type value_type;
return boost::algorithm::is_sorted (first, last, std::less_equal<value_type>());
}
/// \fn is_strictly_increasing ( const R &range )
/// \return true if the entire sequence is strictly increasing; i.e, each item is greater
/// than the previous one
///
/// \param range The range to be tested.
///
/// \note This function will return false for sequences that contain items that compare
/// equal. If that is not what you intended, you should use is_increasing instead.
template <typename R>
BOOST_CXX14_CONSTEXPR bool is_strictly_increasing ( const R &range )
{
return is_strictly_increasing ( boost::begin ( range ), boost::end ( range ));
}
/// \fn is_strictly_decreasing ( ForwardIterator first, ForwardIterator last )
/// \return true if the entire sequence is strictly decreasing; i.e, each item is less than
/// the previous one
///
/// \param first The start of the sequence to be tested.
/// \param last One past the end of the sequence
///
/// \note This function will return false for sequences that contain items that compare
/// equal. If that is not what you intended, you should use is_decreasing instead.
template <typename ForwardIterator>
BOOST_CXX14_CONSTEXPR bool is_strictly_decreasing ( ForwardIterator first, ForwardIterator last )
{
typedef typename std::iterator_traits<ForwardIterator>::value_type value_type;
return boost::algorithm::is_sorted (first, last, std::greater_equal<value_type>());
}
/// \fn is_strictly_decreasing ( const R &range )
/// \return true if the entire sequence is strictly decreasing; i.e, each item is less than
/// the previous one
///
/// \param range The range to be tested.
///
/// \note This function will return false for sequences that contain items that compare
/// equal. If that is not what you intended, you should use is_decreasing instead.
template <typename R>
BOOST_CXX14_CONSTEXPR bool is_strictly_decreasing ( const R &range )
{
return is_strictly_decreasing ( boost::begin ( range ), boost::end ( range ));
}
}} // namespace boost
#endif // BOOST_ALGORITHM_ORDERED_HPP