Boost C++ Libraries

boost/geometry/core/mutable_range.hpp

// Boost.Geometry (aka GGL, Generic Geometry Library)

// Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
// Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
// Copyright (c) 2009-2012 Mateusz Loskot, London, UK.

// This file was modified by Oracle on 2020-2023.
// Modifications copyright (c) 2020-2023 Oracle and/or its affiliates.
// Contributed and/or modified by Vissarion Fysikopoulos, on behalf of Oracle
// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle

// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.

// 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)

#ifndef BOOST_GEOMETRY_CORE_MUTABLE_RANGE_HPP
#define BOOST_GEOMETRY_CORE_MUTABLE_RANGE_HPP


#include <type_traits>

#include <boost/range/size_type.hpp>
#include <boost/range/value_type.hpp>


namespace boost { namespace geometry
{


namespace traits
{

/*!
\brief Metafunction to define the argument passed to the three
    traits classes clear, push_back and resize
\ingroup mutable_range
 */
template <typename Range>
struct rvalue_type
{
    typedef typename std::remove_reference<Range>::type& type;
};


/*!
\brief Traits class to clear a geometry
\ingroup mutable_range
 */
template <typename Range>
struct clear
{
    static inline void apply(typename rvalue_type<Range>::type range)
    {
        range.clear();
    }
};


/*!
\brief Traits class to append a point to a range (ring, linestring, multi*)
\ingroup mutable_range
 */
template <typename Range>
struct push_back
{
    typedef typename boost::range_value
        <
            typename std::remove_reference<Range>::type
        >::type item_type;

    static inline void apply(typename rvalue_type<Range>::type range,
                 item_type const& item)
    {
        range.push_back(item);
    }

    static inline void apply(typename rvalue_type<Range>::type range,
                 item_type && item)
    {
        range.push_back(std::move(item));
    }
};


/*!
\brief Traits class to append an element of geometry collection
\ingroup mutable_range
 */
template <typename Range>
struct emplace_back
{
    // When specializing it'd be enough to only implement it for one argument
    // because we'll use it to pass one object of type potentially different
    // than range_value but which range_value can be constructed from.
    template <typename ...Args>
    static inline void apply(typename rvalue_type<Range>::type range,
                             Args&&... args)
    {
        range.emplace_back(std::forward<Args>(args)...);
    }
};


/*!
\brief Traits class to append a point to a range (ring, linestring, multi*)
\ingroup mutable_range
 */
template <typename Range>
struct resize
{
    using size_type = typename boost::range_size
        <
            typename std::remove_reference<Range>::type
        >::type;

    static inline void apply(typename rvalue_type<Range>::type range,
                             size_type new_size)
    {
        range.resize(new_size);
    }
};


} // namespace traits


}} // namespace boost::geometry


#endif // BOOST_GEOMETRY_CORE_MUTABLE_RANGE_HPP