boost/poly_collection/detail/segment.hpp
/* Copyright 2016-2017 Joaquin M Lopez Munoz.
* 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/libs/poly_collection for library home page.
*/
#ifndef BOOST_POLY_COLLECTION_DETAIL_SEGMENT_HPP
#define BOOST_POLY_COLLECTION_DETAIL_SEGMENT_HPP
#if defined(_MSC_VER)
#pragma once
#endif
#include <iterator>
#include <memory>
#include <type_traits>
#include <utility>
namespace boost{
namespace poly_collection{
namespace detail{
/* segment<Model,Allocator> encapsulates implementations of
* Model::segment_backend virtual interface under a value-semantics type for
* use by poly_collection. The techique is described by Sean Parent at slides
* 157-205 of
* https://github.com/sean-parent/sean-parent.github.com/wiki/
* presentations/2013-09-11-cpp-seasoning/cpp-seasoning.pdf
* with one twist: when the type of the implementation can be known at compile
* time, a downcast is done and non-virtual member functions (named with a nv_
* prefix) are used: this increases the performance of some operations.
*/
template<typename Model,typename Allocator>
class segment
{
public:
using value_type=typename Model::value_type;
using base_iterator=typename Model::base_iterator;
using const_base_iterator=typename Model::const_base_iterator;
using base_sentinel=typename Model::base_sentinel;
using const_base_sentinel=typename Model::const_base_sentinel;
template<typename T>
using iterator=typename Model::template iterator<T>;
template<typename T>
using const_iterator=typename Model::template const_iterator<T>;
template<typename T>
static segment make(const Allocator& al)
{
return Model::template make<T>(al);
}
/* clones the implementation of x with no elements */
static segment make_from_prototype(const segment& x)
{
return {from_prototype{},x};
}
segment(const segment& x):pimpl{x.impl().copy()}{set_sentinel();}
segment(segment&& x)=default;
segment& operator=(segment x) // TODO: Why do we need this?
{
pimpl=std::move(x.pimpl);
snt=x.snt;
return *this;
}
friend bool operator==(const segment& x,const segment& y)
{
if(typeid(*(x.pimpl))!=typeid(*(y.pimpl)))return false;
else return x.impl().equal(y.impl());
}
friend bool operator!=(const segment& x,const segment& y){return !(x==y);}
base_iterator begin()const noexcept{return impl().begin();}
template<typename U>
base_iterator begin()const noexcept{return impl<U>().nv_begin();}
base_iterator end()const noexcept{return impl().end();}
template<typename U>
base_iterator end()const noexcept{return impl<U>().nv_end();}
base_sentinel sentinel()const noexcept{return snt;}
bool empty()const noexcept{return impl().empty();}
template<typename U>
bool empty()const noexcept{return impl<U>().nv_empty();}
std::size_t size()const noexcept{return impl().size();}
template<typename U>
std::size_t size()const noexcept{return impl<U>().nv_size();}
std::size_t max_size()const noexcept{return impl().max_size();}
template<typename U>
std::size_t max_size()const noexcept
{return impl<U>().nv_max_size();}
void reserve(std::size_t n){filter(impl().reserve(n));}
template<typename U>
void reserve(std::size_t n){filter(impl<U>().nv_reserve(n));}
std::size_t capacity()const noexcept{return impl().capacity();}
template<typename U>
std::size_t capacity()const noexcept
{return impl<U>().nv_capacity();}
void shrink_to_fit(){filter(impl().shrink_to_fit());}
template<typename U>
void shrink_to_fit(){filter(impl<U>().nv_shrink_to_fit());}
template<typename U,typename Iterator,typename... Args>
base_iterator emplace(Iterator it,Args&&... args)
{
return filter(impl<U>().nv_emplace(it,std::forward<Args>(args)...));
}
template<typename U,typename... Args>
base_iterator emplace_back(Args&&... args)
{
return filter(impl<U>().nv_emplace_back(std::forward<Args>(args)...));
}
template<typename T>
base_iterator push_back(const T& x)
{
return filter(impl().push_back(subaddress(x)));
}
template<
typename T,
typename std::enable_if<
!std::is_lvalue_reference<T>::value&&!std::is_const<T>::value
>::type* =nullptr
>
base_iterator push_back(T&& x)
{
return filter(impl().push_back_move(subaddress(x)));
}
template<typename U>
base_iterator push_back_terminal(U&& x)
{
return filter(
impl<typename std::decay<U>::type>().nv_push_back(std::forward<U>(x)));
}
template<typename T>
base_iterator insert(const_base_iterator it,const T& x)
{
return filter(impl().insert(it,subaddress(x)));
}
template<typename U,typename T>
base_iterator insert(const_iterator<U> it,const T& x)
{
return filter(
impl<U>().nv_insert(it,*static_cast<const U*>(subaddress(x))));
}
template<
typename T,
typename std::enable_if<
!std::is_lvalue_reference<T>::value&&!std::is_const<T>::value
>::type* =nullptr
>
base_iterator insert(const_base_iterator it,T&& x)
{
return filter(impl().insert_move(it,subaddress(x)));
}
template<
typename U,typename T,
typename std::enable_if<
!std::is_lvalue_reference<T>::value&&!std::is_const<T>::value
>::type* =nullptr
>
base_iterator insert(const_iterator<U> it,T&& x)
{
return filter(
impl<U>().nv_insert(it,std::move(*static_cast<U*>(subaddress(x)))));
}
template<typename InputIterator>
base_iterator insert(InputIterator first,InputIterator last)
{
return filter(
impl<typename std::iterator_traits<InputIterator>::value_type>().
nv_insert(first,last));
}
template<typename InputIterator>
base_iterator insert(
const_base_iterator it,InputIterator first,InputIterator last)
{
return insert(
const_iterator<
typename std::iterator_traits<InputIterator>::value_type>(it),
first,last);
}
template<typename U,typename InputIterator>
base_iterator insert(
const_iterator<U> it,InputIterator first,InputIterator last)
{
return filter(impl<U>().nv_insert(it,first,last));
}
base_iterator erase(const_base_iterator it)
{
return filter(impl().erase(it));
}
template<typename U>
base_iterator erase(const_iterator<U> it)
{
return filter(impl<U>().nv_erase(it));
}
base_iterator erase(const_base_iterator f,const_base_iterator l)
{
return filter(impl().erase(f,l));
}
template<typename U>
base_iterator erase(const_iterator<U> f,const_iterator<U> l)
{
return filter(impl<U>().nv_erase(f,l));
}
template<typename Iterator>
base_iterator erase_till_end(Iterator f)
{
return filter(impl().erase_till_end(f));
}
template<typename Iterator>
base_iterator erase_from_begin(Iterator l)
{
return filter(impl().erase_from_begin(l));
}
void clear()noexcept{filter(impl().clear());}
template<typename U>
void clear()noexcept{filter(impl<U>().nv_clear());}
private:
using segment_backend=typename Model::segment_backend;
template<typename Concrete>
using segment_backend_implementation=typename Model::
template segment_backend_implementation<Concrete,Allocator>;
using segment_backend_unique_ptr=
typename segment_backend::segment_backend_unique_ptr;
using range=typename segment_backend::range;
struct from_prototype{};
segment(segment_backend_unique_ptr&& pimpl):
pimpl{std::move(pimpl)}{set_sentinel();}
segment(from_prototype,const segment& x):
pimpl{x.impl().empty_copy()}{set_sentinel();}
segment_backend& impl()noexcept{return *pimpl;}
const segment_backend& impl()const noexcept{return *pimpl;}
template<typename Concrete>
segment_backend_implementation<Concrete>& impl()noexcept
{
return static_cast<segment_backend_implementation<Concrete>&>(impl());
}
template<typename Concrete>
const segment_backend_implementation<Concrete>& impl()const noexcept
{
return
static_cast<const segment_backend_implementation<Concrete>&>(impl());
}
template<typename T>
static void* subaddress(T& x){return Model::subaddress(x);}
template<typename T>
static const void* subaddress(const T& x){return Model::subaddress(x);}
void set_sentinel(){filter(impl().end());}
void filter(base_sentinel x){snt=x;}
base_iterator filter(const range& x){snt=x.second;return x.first;}
segment_backend_unique_ptr pimpl;
base_sentinel snt;
};
} /* namespace poly_collection::detail */
} /* namespace poly_collection */
} /* namespace boost */
#endif