include/__split_buffer

// -*- C++ -*-
#ifndef _LIBCPP_SPLIT_BUFFER
#define _LIBCPP_SPLIT_BUFFER

#include <__config>
#include <type_traits>
#include <algorithm>

#pragma GCC system_header

_LIBCPP_BEGIN_NAMESPACE_STD

template <bool>
class __split_buffer_common
{
protected:
 void __throw_length_error() const;
 void __throw_out_of_range() const;
};

template <class _Tp, class _Allocator = allocator<_Tp> >
struct __split_buffer
 : private __split_buffer_common<true>
{
private:
 __split_buffer(const __split_buffer&);
 __split_buffer& operator=(const __split_buffer&);
public:
 typedef _Tp value_type; 
 typedef _Allocator allocator_type;
 typedef typename remove_reference<allocator_type>::type __alloc_rr;
 typedef allocator_traits<__alloc_rr> __alloc_traits;
 typedef value_type& reference;
 typedef const value_type& const_reference;
 typedef typename __alloc_traits::size_type size_type;
 typedef typename __alloc_traits::difference_type difference_type;
 typedef typename __alloc_traits::pointer pointer;
 typedef typename __alloc_traits::const_pointer const_pointer;
 typedef pointer iterator;
 typedef const_pointer const_iterator;

 pointer __first_;
 pointer __begin_;
 pointer __end_;
 __compressed_pair<pointer, allocator_type> __end_cap_;

 typedef typename add_lvalue_reference<allocator_type>::type __alloc_ref;
 typedef typename add_lvalue_reference<allocator_type>::type __alloc_const_ref;

 _LIBCPP_INLINE_VISIBILITY __alloc_rr& __alloc() {return __end_cap_.second();}
 _LIBCPP_INLINE_VISIBILITY const __alloc_rr& __alloc() const {return __end_cap_.second();}
 _LIBCPP_INLINE_VISIBILITY pointer& __end_cap() {return __end_cap_.first();}
 _LIBCPP_INLINE_VISIBILITY const pointer& __end_cap() const {return __end_cap_.first();}

 __split_buffer();
 explicit __split_buffer(__alloc_rr& __a);
 explicit __split_buffer(const __alloc_rr& __a);
 __split_buffer(size_type __cap, size_type __start, __alloc_rr& __a);
 ~__split_buffer();

#ifdef _LIBCPP_MOVE
 __split_buffer(__split_buffer&& __c);
 __split_buffer(__split_buffer&& __c, const __alloc_rr& __a);
 __split_buffer& operator=(__split_buffer&& __c);
#endif

 _LIBCPP_INLINE_VISIBILITY iterator begin() {return __begin_;}
 _LIBCPP_INLINE_VISIBILITY const_iterator begin() const {return __begin_;}
 _LIBCPP_INLINE_VISIBILITY iterator end() {return __end_;}
 _LIBCPP_INLINE_VISIBILITY const_iterator end() const {return __end_;}

 _LIBCPP_INLINE_VISIBILITY void clear() {__destruct_at_end(__begin_);}
 _LIBCPP_INLINE_VISIBILITY size_type size() const {return static_cast<size_type>(__end_ - __begin_);}
 _LIBCPP_INLINE_VISIBILITY bool empty() const {return __end_ == __begin_;}
 _LIBCPP_INLINE_VISIBILITY size_type capacity() const {return static_cast<size_type>(__end_cap() - __first_);}
 _LIBCPP_INLINE_VISIBILITY size_type __front_spare() const {return static_cast<size_type>(__begin_ - __first_);}
 _LIBCPP_INLINE_VISIBILITY size_type __back_spare() const {return static_cast<size_type>(__end_cap() - __end_);}

 _LIBCPP_INLINE_VISIBILITY reference front() {return *__begin_;}
 _LIBCPP_INLINE_VISIBILITY const_reference front() const {return *__begin_;}
 _LIBCPP_INLINE_VISIBILITY reference back() {return *(__end_ - 1);}
 _LIBCPP_INLINE_VISIBILITY const_reference back() const {return *(__end_ - 1);}

 void reserve(size_type __n);
 void shrink_to_fit();
 void push_front(const_reference __x);
 void push_back(const_reference __x);
#ifdef _LIBCPP_MOVE
 void push_front(value_type&& __x);
 void push_back(value_type&& __x);
 template <class... _Args>
 void emplace_back(_Args&&... __args);
#endif

 _LIBCPP_INLINE_VISIBILITY void pop_front() {__destruct_at_begin(__begin_+1);}
 _LIBCPP_INLINE_VISIBILITY void pop_back() {__destruct_at_end(__end_-1);}

 void __construct_at_end(size_type __n);
 void __construct_at_end(size_type __n, false_type);
 void __construct_at_end(size_type __n, true_type);
 void __construct_at_end(size_type __n, const_reference __x);
 void __construct_at_end(size_type __n, const_reference __x, false_type);
 void __construct_at_end(size_type __n, const_reference __x, true_type);
 template <class _InputIter>
 typename enable_if
 <
 __is_input_iterator<_InputIter>::value &&
 !__is_forward_iterator<_InputIter>::value,
 void
 >::type
 __construct_at_end(_InputIter __first, _InputIter __last);
 template <class _ForwardIterator>
 typename enable_if
 <
 __is_forward_iterator<_ForwardIterator>::value,
 void
 >::type
 __construct_at_end(_ForwardIterator __first, _ForwardIterator __last);

 _LIBCPP_INLINE_VISIBILITY void __destruct_at_begin(pointer __new_begin)
 {__destruct_at_begin(__new_begin, has_trivial_destructor<value_type>());}
 void __destruct_at_begin(pointer __new_begin, false_type);
 void __destruct_at_begin(pointer __new_begin, true_type);

 _LIBCPP_INLINE_VISIBILITY void __destruct_at_end(pointer __new_last)
 {__destruct_at_end(__new_last, has_trivial_destructor<value_type>());}
 void __destruct_at_end(pointer __new_last, false_type);
 void __destruct_at_end(pointer __new_last, true_type);

 void swap(__split_buffer& __x);

 bool __invariants() const;

private:
 void __move_assign_alloc(const __split_buffer& __c, true_type)
 {
 __alloc() = _STD::move(__c.__alloc());
 }

 void __move_assign_alloc(const __split_buffer& __c, false_type)
 {}

 static void __swap_alloc(__alloc_rr& __x, __alloc_rr& __y)
 {__swap_alloc(__x, __y, integral_constant<bool,
 __alloc_traits::propagate_on_container_swap::value>());}

 static void __swap_alloc(__alloc_rr& __x, __alloc_rr& __y, true_type)
 {
 using _STD::swap;
 swap(__x, __y);
 }
 static void __swap_alloc(__alloc_rr& __x, __alloc_rr& __y, false_type)
 {}
};

template <class _Tp, class _Allocator>
bool
__split_buffer<_Tp, _Allocator>::__invariants() const
{
 if (__first_ == nullptr)
 {
 if (__begin_ != nullptr)
 return false;
 if (__end_ != nullptr)
 return false;
 if (__end_cap() != nullptr)
 return false;
 }
 else
 {
 if (__begin_ < __first_)
 return false;
 if (__end_ < __begin_)
 return false;
 if (__end_cap() < __end_)
 return false;
 }
 return true;
}

// Default constructs __n objects starting at __end_
// throws if construction throws
// Precondition: __n > 0
// Precondition: size() + __n <= capacity()
// Postcondition: size() == size() + __n
template <class _Tp, class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
void
__split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n)
{
 __construct_at_end(__n, __is_zero_default_constructible<value_type>());
}

template <class _Tp, class _Allocator>
void
__split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n, false_type)
{
 __alloc_rr& __a = this->__alloc();
 do
 {
 __alloc_traits::construct(__a, _STD::__to_raw_pointer(this->__end_), value_type());
 ++this->__end_;
 --__n;
 } while (__n > 0);
}

template <class _Tp, class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
void
__split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n, true_type)
{
 _STD::memset(this->__end_, 0, __n*sizeof(value_type));
 this->__end_ += __n;
}

// Copy constructs __n objects starting at __end_ from __x
// throws if construction throws
// Precondition: __n > 0
// Precondition: size() + __n <= capacity()
// Postcondition: size() == old size() + __n
// Postcondition: [i] == __x for all i in [size() - __n, __n)
template <class _Tp, class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
void
__split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n, const_reference __x)
{
 __construct_at_end(__n, __x, integral_constant<bool, has_trivial_copy_constructor<value_type>::value &&
 has_trivial_copy_assign<value_type>::value>());
}

template <class _Tp, class _Allocator>
void
__split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n, const_reference __x, false_type)
{
 __alloc_rr& __a = this->__alloc();
 do
 {
 __alloc_traits::construct(__a, _STD::__to_raw_pointer(this->__end_), __x);
 ++this->__end_;
 --__n;
 } while (__n > 0);
}

template <class _Tp, class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
void
__split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n, const_reference __x, true_type)
{
 _STD::fill_n(this->__end_, __n, __x);
 this->__end_ += __n;
}

template <class _Tp, class _Allocator>
template <class _InputIter>
typename enable_if
<
 __is_input_iterator<_InputIter>::value &&
 !__is_forward_iterator<_InputIter>::value,
 void
>::type
__split_buffer<_Tp, _Allocator>::__construct_at_end(_InputIter __first, _InputIter __last)
{
 __alloc_rr& __a = this->__alloc();
 for (; __first != __last; ++__first)
 {
 if (__end_ == __end_cap())
 {
 size_type __old_cap = __end_cap() - __first_;
 size_type __new_cap = _STD::max<size_type>(2 * __old_cap, 8);
 __split_buffer __buf(__new_cap, 0, __a);
 for (pointer __p = __begin_; __p != __end_; ++__p, ++__buf.__end_)
 __alloc_traits::construct(__buf.__alloc(),
 _STD::__to_raw_pointer(__buf.__end_), _STD::move(*__p));
 swap(__buf);
 }
 __alloc_traits::construct(__a, _STD::__to_raw_pointer(this->__end_), *__first);
 ++this->__end_;
 }
}

template <class _Tp, class _Allocator>
template <class _ForwardIterator>
typename enable_if
<
 __is_forward_iterator<_ForwardIterator>::value,
 void
>::type
__split_buffer<_Tp, _Allocator>::__construct_at_end(_ForwardIterator __first, _ForwardIterator __last)
{
 __alloc_rr& __a = this->__alloc();
 for (; __first != __last; ++__first)
 {
 __alloc_traits::construct(__a, _STD::__to_raw_pointer(this->__end_), *__first);
 ++this->__end_;
 }
}

template <class _Tp, class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
void
__split_buffer<_Tp, _Allocator>::__destruct_at_begin(pointer __new_begin, false_type)
{
 while (__begin_ < __new_begin)
 __alloc_traits::destroy(__alloc(), __begin_++);
}

template <class _Tp, class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
void
__split_buffer<_Tp, _Allocator>::__destruct_at_begin(pointer __new_begin, true_type)
{
 __begin_ = __new_begin;
}

template <class _Tp, class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
void
__split_buffer<_Tp, _Allocator>::__destruct_at_end(pointer __new_last, false_type)
{
 while (__new_last < __end_)
 __alloc_traits::destroy(__alloc(), --__end_);
}

template <class _Tp, class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
void
__split_buffer<_Tp, _Allocator>::__destruct_at_end(pointer __new_last, true_type)
{
 __end_ = __new_last;
}

template <class _Tp, class _Allocator>
__split_buffer<_Tp, _Allocator>::__split_buffer(size_type __cap, size_type __start, __alloc_rr& __a)
 : __end_cap_(0, __a)
{
 __first_ = __cap != 0 ? __alloc_traits::allocate(__alloc(), __cap) : nullptr;
 __begin_ = __end_ = __first_ + __start;
 __end_cap() = __first_ + __cap;
}

template <class _Tp, class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
__split_buffer<_Tp, _Allocator>::__split_buffer()
 : __first_(0), __begin_(0), __end_(0), __end_cap_(0)
{
}

template <class _Tp, class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
__split_buffer<_Tp, _Allocator>::__split_buffer(__alloc_rr& __a)
 : __first_(0), __begin_(0), __end_(0), __end_cap_(0, __a)
{
}

template <class _Tp, class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
__split_buffer<_Tp, _Allocator>::__split_buffer(const __alloc_rr& __a)
 : __first_(0), __begin_(0), __end_(0), __end_cap_(0, __a)
{
}

template <class _Tp, class _Allocator>
__split_buffer<_Tp, _Allocator>::~__split_buffer()
{
 clear();
 if (__first_)
 __alloc_traits::deallocate(__alloc(), __first_, capacity());
}

#ifdef _LIBCPP_MOVE

template <class _Tp, class _Allocator>
__split_buffer<_Tp, _Allocator>::__split_buffer(__split_buffer&& __c)
 : __first_(_STD::move(__c.__first_)),
 __begin_(_STD::move(__c.__begin_)),
 __end_(_STD::move(__c.__end_)),
 __end_cap_(_STD::move(__c.__end_cap_))
{
 __c.__first_ = nullptr;
 __c.__begin_ = nullptr;
 __c.__end_ = nullptr;
 __c.__end_cap() = nullptr;
}

template <class _Tp, class _Allocator>
__split_buffer<_Tp, _Allocator>::__split_buffer(__split_buffer&& __c, const __alloc_rr& __a)
 : __end_cap_(__a)
{
 if (__a == __c.__alloc())
 {
 __first_ = __c.__first_;
 __begin_ = __c.__begin_;
 __end_ = __c.__end_;
 __end_cap() = __c.__end_cap();
 __c.__first_ = nullptr;
 __c.__begin_ = nullptr;
 __c.__end_ = nullptr;
 __c.__end_cap() = nullptr;
 }
 else
 {
 size_type __cap = __c.size();
 __first_ = __alloc_traits::allocate(__alloc(), __cap);
 __begin_ = __end_ = __first_;
 __end_cap() = __first_ + __cap;
 typedef move_iterator<iterator> _I;
 __construct_at_end(_I(__c.begin()), _I(__c.end()));
 }
}

template <class _Tp, class _Allocator>
__split_buffer<_Tp, _Allocator>&
__split_buffer<_Tp, _Allocator>::operator=(__split_buffer&& __c)
{
 clear();
 shrink_to_fit();
 __first_ = __c.__first_;
 __begin_ = __c.__begin_;
 __end_ = __c.__end_;
 __end_cap() = __c.__end_cap();
 __move_assign_alloc(__c,
 integral_constant<bool,
 __alloc_traits::propagate_on_container_move_assignment::value>());
 __c.__first_ = __c.__begin_ = __c.__end_ = __c.__end_cap() = nullptr;
 return *this;
}

#endif

template <class _Tp, class _Allocator>
void
__split_buffer<_Tp, _Allocator>::swap(__split_buffer& __x)
{
 _STD::swap(__first_, __x.__first_);
 _STD::swap(__begin_, __x.__begin_);
 _STD::swap(__end_, __x.__end_);
 _STD::swap(__end_cap(), __x.__end_cap());
 __swap_alloc(__alloc(), __x.__alloc());
}

template <class _Tp, class _Allocator>
void
__split_buffer<_Tp, _Allocator>::reserve(size_type __n)
{
 if (__n < capacity())
 {
 __split_buffer<value_type, __alloc_rr&> __t(__n, 0, __alloc());
 __t.__construct_at_end(move_iterator<pointer>(__begin_),
 move_iterator<pointer>(__end_));
 _STD::swap(__first_, __t.__first_);
 _STD::swap(__begin_, __t.__begin_);
 _STD::swap(__end_, __t.__end_);
 _STD::swap(__end_cap(), __t.__end_cap());
 }
}

template <class _Tp, class _Allocator>
void
__split_buffer<_Tp, _Allocator>::shrink_to_fit()
{
 if (capacity() > size())
 {
#ifndef _LIBCPP_NO_EXCEPTIONS
 try
 {
#endif
 __split_buffer<value_type, __alloc_rr&> __t(size(), 0, __alloc());
 __t.__construct_at_end(move_iterator<pointer>(__begin_),
 move_iterator<pointer>(__end_));
 __t.__end_ = __t.__begin_ + (__end_ - __begin_);
 _STD::swap(__first_, __t.__first_);
 _STD::swap(__begin_, __t.__begin_);
 _STD::swap(__end_, __t.__end_);
 _STD::swap(__end_cap(), __t.__end_cap());
#ifndef _LIBCPP_NO_EXCEPTIONS
 }
 catch (...)
 {
 }
#endif
 }
}

template <class _Tp, class _Allocator>
void
__split_buffer<_Tp, _Allocator>::push_front(const_reference __x)
{
 if (__begin_ == __first_)
 {
 if (__end_ < __end_cap())
 {
 difference_type __d = __end_cap() - __end_;
 __d = (__d + 1) / 2;
 __begin_ = _STD::move_backward(__begin_, __end_, __end_ + __d);
 __end_ += __d;
 }
 else
 {
 size_type __c = max<size_type>(2 * (__end_cap() - __first_), 1);
 __split_buffer<value_type, __alloc_rr&> __t(__c, (__c + 3) / 4, __alloc());
 __t.__construct_at_end(move_iterator<pointer>(__begin_),
 move_iterator<pointer>(__end_));
 _STD::swap(__first_, __t.__first_);
 _STD::swap(__begin_, __t.__begin_);
 _STD::swap(__end_, __t.__end_);
 _STD::swap(__end_cap(), __t.__end_cap());
 }
 }
 __alloc_traits::construct(__alloc(), _STD::__to_raw_pointer(__begin_-1), __x);
 --__begin_;
}

#ifdef _LIBCPP_MOVE

template <class _Tp, class _Allocator>
void
__split_buffer<_Tp, _Allocator>::push_front(value_type&& __x)
{
 if (__begin_ == __first_)
 {
 if (__end_ < __end_cap())
 {
 difference_type __d = __end_cap() - __end_;
 __d = (__d + 1) / 2;
 __begin_ = _STD::move_backward(__begin_, __end_, __end_ + __d);
 __end_ += __d;
 }
 else
 {
 size_type __c = max<size_type>(2 * (__end_cap() - __first_), 1);
 __split_buffer<value_type, __alloc_rr&> __t(__c, (__c + 3) / 4, __alloc());
 __t.__construct_at_end(move_iterator<pointer>(__begin_),
 move_iterator<pointer>(__end_));
 _STD::swap(__first_, __t.__first_);
 _STD::swap(__begin_, __t.__begin_);
 _STD::swap(__end_, __t.__end_);
 _STD::swap(__end_cap(), __t.__end_cap());
 }
 }
 __alloc_traits::construct(__alloc(), _STD::__to_raw_pointer(__begin_-1),
 _STD::move(__x));
 --__begin_;
}

#endif

template <class _Tp, class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
void
__split_buffer<_Tp, _Allocator>::push_back(const_reference __x)
{
 if (__end_ == __end_cap())
 {
 if (__begin_ > __first_)
 {
 difference_type __d = __begin_ - __first_;
 __d = (__d + 1) / 2;
 __end_ = _STD::move(__begin_, __end_, __begin_ - __d);
 __begin_ -= __d;
 }
 else
 {
 size_type __c = max<size_type>(2 * (__end_cap() - __first_), 1);
 __split_buffer<value_type, __alloc_rr&> __t(__c, __c / 4, __alloc());
 __t.__construct_at_end(move_iterator<pointer>(__begin_),
 move_iterator<pointer>(__end_));
 _STD::swap(__first_, __t.__first_);
 _STD::swap(__begin_, __t.__begin_);
 _STD::swap(__end_, __t.__end_);
 _STD::swap(__end_cap(), __t.__end_cap());
 }
 }
 __alloc_traits::construct(__alloc(), _STD::__to_raw_pointer(__end_), __x);
 ++__end_;
}

#ifdef _LIBCPP_MOVE

template <class _Tp, class _Allocator>
void
__split_buffer<_Tp, _Allocator>::push_back(value_type&& __x)
{
 if (__end_ == __end_cap())
 {
 if (__begin_ > __first_)
 {
 difference_type __d = __begin_ - __first_;
 __d = (__d + 1) / 2;
 __end_ = _STD::move(__begin_, __end_, __begin_ - __d);
 __begin_ -= __d;
 }
 else
 {
 size_type __c = max<size_type>(2 * (__end_cap() - __first_), 1);
 __split_buffer<value_type, __alloc_rr&> __t(__c, __c / 4, __alloc());
 __t.__construct_at_end(move_iterator<pointer>(__begin_),
 move_iterator<pointer>(__end_));
 _STD::swap(__first_, __t.__first_);
 _STD::swap(__begin_, __t.__begin_);
 _STD::swap(__end_, __t.__end_);
 _STD::swap(__end_cap(), __t.__end_cap());
 }
 }
 __alloc_traits::construct(__alloc(), _STD::__to_raw_pointer(__end_),
 _STD::move(__x));
 ++__end_;
}

template <class _Tp, class _Allocator>
template <class... _Args>
void
__split_buffer<_Tp, _Allocator>::emplace_back(_Args&&... __args)
{
 if (__end_ == __end_cap())
 {
 if (__begin_ > __first_)
 {
 difference_type __d = __begin_ - __first_;
 __d = (__d + 1) / 2;
 __end_ = _STD::move(__begin_, __end_, __begin_ - __d);
 __begin_ -= __d;
 }
 else
 {
 size_type __c = max<size_type>(2 * (__end_cap() - __first_), 1);
 __split_buffer<value_type, __alloc_rr&> __t(__c, __c / 4, __alloc());
 __t.__construct_at_end(move_iterator<pointer>(__begin_),
 move_iterator<pointer>(__end_));
 _STD::swap(__first_, __t.__first_);
 _STD::swap(__begin_, __t.__begin_);
 _STD::swap(__end_, __t.__end_);
 _STD::swap(__end_cap(), __t.__end_cap());
 }
 }
 __alloc_traits::construct(__alloc(), _STD::__to_raw_pointer(__end_),
 _STD::forward<_Args>(__args)...);
 ++__end_;
}

#endif

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP_SPLIT_BUFFER