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/// \file
// Range v3 library
//
// Copyright Eric Niebler 2014-present
//
// Use, modification and distribution is subject to 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)
//
// Project home: https://github.com/ericniebler/range-v3
//
//===-------------------------- algorithm ---------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef RANGES_V3_ALGORITHM_PARTITION_HPP
#define RANGES_V3_ALGORITHM_PARTITION_HPP
#include <meta/meta.hpp>
#include <range/v3/range_fwd.hpp>
#include <range/v3/functional/identity.hpp>
#include <range/v3/functional/invoke.hpp>
#include <range/v3/iterator/concepts.hpp>
#include <range/v3/iterator/operations.hpp>
#include <range/v3/iterator/traits.hpp>
#include <range/v3/range/access.hpp>
#include <range/v3/range/concepts.hpp>
#include <range/v3/range/dangling.hpp>
#include <range/v3/range/traits.hpp>
#include <range/v3/utility/static_const.hpp>
#include <range/v3/utility/swap.hpp>
#include <range/v3/detail/prologue.hpp>
namespace ranges
{
/// \addtogroup group-algorithms
/// @{
/// \cond
namespace detail
{
template<typename I, typename S, typename C, typename P>
constexpr I partition_impl(I first, S last, C pred, P proj, std::forward_iterator_tag)
{
while(true)
{
if(first == last)
return first;
if(!invoke(pred, invoke(proj, *first)))
break;
++first;
}
for(I p = first; ++p != last;)
{
if(invoke(pred, invoke(proj, *p)))
{
ranges::iter_swap(first, p);
++first;
}
}
return first;
}
template<typename I, typename S, typename C, typename P>
constexpr I partition_impl(I first, S end_, C pred, P proj, std::bidirectional_iterator_tag)
{
I last = ranges::next(first, end_);
while(true)
{
while(true)
{
if(first == last)
return first;
if(!invoke(pred, invoke(proj, *first)))
break;
++first;
}
do
{
if(first == --last)
return first;
} while(!invoke(pred, invoke(proj, *last)));
ranges::iter_swap(first, last);
++first;
}
}
} // namespace detail
/// \endcond
RANGES_FUNC_BEGIN(partition)
/// \brief function template \c partition
template(typename I, typename S, typename C, typename P = identity)(
requires permutable<I> AND sentinel_for<S, I> AND
indirect_unary_predicate<C, projected<I, P>>)
constexpr I RANGES_FUNC(partition)(I first, S last, C pred, P proj = P{})
{
return detail::partition_impl(std::move(first),
std::move(last),
std::move(pred),
std::move(proj),
iterator_tag_of<I>());
}
/// \overload
template(typename Rng, typename C, typename P = identity)(
requires forward_range<Rng> AND permutable<iterator_t<Rng>> AND
indirect_unary_predicate<C, projected<iterator_t<Rng>, P>>)
constexpr borrowed_iterator_t<Rng> RANGES_FUNC(partition)(Rng && rng, C pred, P proj = P{})
{
return detail::partition_impl(begin(rng),
end(rng),
std::move(pred),
std::move(proj),
iterator_tag_of<iterator_t<Rng>>());
}
RANGES_FUNC_END(partition)
namespace cpp20
{
using ranges::partition;
}
/// @}
} // namespace ranges
#include <range/v3/detail/epilogue.hpp>
#endif
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