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ring_span.hpp
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ring_span.hpp
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//
// Copyright (c) 2015 Arthur O'Dwyer
// Copyright 2017-2019 by Martin Moene
//
// https://github.com/martinmoene/ring-span-lite
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#pragma once
#ifndef NONSTD_RING_SPAN_LITE_HPP
#define NONSTD_RING_SPAN_LITE_HPP
#define ring_span_lite_MAJOR 0
#define ring_span_lite_MINOR 6
#define ring_span_lite_PATCH 0
#define ring_span_lite_VERSION nsrs_STRINGIFY(ring_span_lite_MAJOR) "." nsrs_STRINGIFY(ring_span_lite_MINOR) "." nsrs_STRINGIFY(ring_span_lite_PATCH)
#define nsrs_STRINGIFY( x ) nsrs_STRINGIFY_( x )
#define nsrs_STRINGIFY_( x ) #x
// tweak header support:
#ifdef __has_include
# if __has_include(<nonstd/ring_span.tweak.hpp>)
# include <nonstd/ring_span.tweak.hpp>
# endif
# define nsrs_HAVE_TWEAK_HEADER 1
#else
# define nsrs_HAVE_TWEAK_HEADER 0
//# pragma message("any.hpp: Note: Tweak header not supported.")
#endif
// ring-span-lite configuration:
#define nsrs_RING_SPAN_DEFAULT 0
#define nsrs_RING_SPAN_NONSTD 1
#define nsrs_RING_SPAN_STD 2
#if !defined( nsrs_CONFIG_SELECT_RING_SPAN )
# define nsrs_CONFIG_SELECT_RING_SPAN ( nsrs_HAVE_STD_RING_SPAN ? nsrs_RING_SPAN_STD : nsrs_RING_SPAN_NONSTD )
#endif
#ifndef nsrs_CONFIG_STRICT_P0059
# define nsrs_CONFIG_STRICT_P0059 0
#endif
#define nsrs_RING_SPAN_LITE_EXTENSION (! nsrs_CONFIG_STRICT_P0059)
#ifndef nsrs_CONFIG_POPPER_EMPTY_BASE_CLASS
# define nsrs_CONFIG_POPPER_EMPTY_BASE_CLASS 0
#endif
#if nsrs_CONFIG_STRICT_P0059
# undef nsrs_CONFIG_POPPER_EMPTY_BASE_CLASS
# define nsrs_CONFIG_POPPER_EMPTY_BASE_CLASS 0
#endif
#ifndef nsrs_CONFIG_CONFIRMS_COMPILATION_ERRORS
# define nsrs_CONFIG_CONFIRMS_COMPILATION_ERRORS 0
#endif
// C++ language version detection (C++23 is speculative):
// Note: VC14.0/1900 (VS2015) lacks too much from C++14.
#ifndef nsrs_CPLUSPLUS
# if defined(_MSVC_LANG ) && !defined(__clang__)
# define nsrs_CPLUSPLUS (_MSC_VER == 1900 ? 201103L : _MSVC_LANG )
# else
# define nsrs_CPLUSPLUS __cplusplus
# endif
#endif
#define nsrs_CPP98_OR_GREATER ( nsrs_CPLUSPLUS >= 199711L )
#define nsrs_CPP11_OR_GREATER ( nsrs_CPLUSPLUS >= 201103L )
#define nsrs_CPP11_OR_GREATER_ ( nsrs_CPLUSPLUS >= 201103L )
#define nsrs_CPP14_OR_GREATER ( nsrs_CPLUSPLUS >= 201402L )
#define nsrs_CPP17_OR_GREATER ( nsrs_CPLUSPLUS >= 201703L )
#define nsrs_CPP20_OR_GREATER ( nsrs_CPLUSPLUS >= 202002L )
#define nsrs_CPP23_OR_GREATER ( nsrs_CPLUSPLUS >= 202300L )
// Use C++XX std::ring_span if available and requested:
#define nsrs_HAVE_STD_RING_SPAN 0
//#if nsrs_CPP17_OR_GREATER && defined(__has_include )
//# if __has_include( <any> )
//# define nsrs_HAVE_STD_RING_SPAN 1
//# else
//# define nsrs_HAVE_STD_RING_SPAN 0
//# endif
//#else
//# define nsrs_HAVE_STD_RING_SPAN 0
//#endif
#define nsrs_USES_STD_RING_SPAN ( (nsrs_CONFIG_SELECT_RING_SPAN == nsrs_RING_SPAN_STD) || ((nsrs_CONFIG_SELECT_RING_SPAN == nsrs_RING_SPAN_DEFAULT) && nsrs_HAVE_STD_RING_SPAN) )
// Compiler versions:
//
// MSVC++ 6.0 _MSC_VER == 1200 nsrs_COMPILER_MSVC_VERSION == 60 (Visual Studio 6.0)
// MSVC++ 7.0 _MSC_VER == 1300 nsrs_COMPILER_MSVC_VERSION == 70 (Visual Studio .NET 2002)
// MSVC++ 7.1 _MSC_VER == 1310 nsrs_COMPILER_MSVC_VERSION == 71 (Visual Studio .NET 2003)
// MSVC++ 8.0 _MSC_VER == 1400 nsrs_COMPILER_MSVC_VERSION == 80 (Visual Studio 2005)
// MSVC++ 9.0 _MSC_VER == 1500 nsrs_COMPILER_MSVC_VERSION == 90 (Visual Studio 2008)
// MSVC++ 10.0 _MSC_VER == 1600 nsrs_COMPILER_MSVC_VERSION == 100 (Visual Studio 2010)
// MSVC++ 11.0 _MSC_VER == 1700 nsrs_COMPILER_MSVC_VERSION == 110 (Visual Studio 2012)
// MSVC++ 12.0 _MSC_VER == 1800 nsrs_COMPILER_MSVC_VERSION == 120 (Visual Studio 2013)
// MSVC++ 14.0 _MSC_VER == 1900 nsrs_COMPILER_MSVC_VERSION == 140 (Visual Studio 2015)
// ............ _MSVC_LANG: 201402 for -std:c++14, default
// MSVC++ 14.1 _MSC_VER >= 1910 nsrs_COMPILER_MSVC_VERSION == 141 (Visual Studio 2017)
// ............ _MSVC_LANG: 201402 for -std:c++14, default
// ............ _MSVC_LANG: 201703 for -std:c++17
// MSVC++ 14.2 _MSC_VER >= 1920 nsrs_COMPILER_MSVC_VERSION == 142 (Visual Studio 2019)
#if defined(_MSC_VER ) && !defined(__clang__)
# define nsrs_COMPILER_MSVC_VER (_MSC_VER )
# define nsrs_COMPILER_MSVC_VERSION (_MSC_VER / 10 - 10 * ( 5 + (_MSC_VER < 1900 ) ) )
#else
# define nsrs_COMPILER_MSVC_VER 0
# define nsrs_COMPILER_MSVC_VERSION 0
#endif
#define nsrs_COMPILER_VERSION( major, minor, patch ) ( 10 * ( 10 * (major) + (minor) ) + (patch) )
#if defined(__clang__)
# define nsrs_COMPILER_CLANG_VERSION nsrs_COMPILER_VERSION( __clang_major__, __clang_minor__, __clang_patchlevel__ )
#else
# define nsrs_COMPILER_CLANG_VERSION 0
#endif
#if defined(__GNUC__) && !defined(__clang__)
# define nsrs_COMPILER_GNUC_VERSION nsrs_COMPILER_VERSION( __GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__ )
#else
# define nsrs_COMPILER_GNUC_VERSION 0
#endif
// half-open range [lo..hi):
//#define nsrs_BETWEEN( v, lo, hi ) ( (lo) <= (v) && (v) < (hi) )
// Presence of language and library features:
#ifdef _HAS_CPP0X
# define nsrs_HAS_CPP0X _HAS_CPP0X
#else
# define nsrs_HAS_CPP0X 0
#endif
// Unless defined otherwise below, consider VC14 as C++11 for ring-span-lite:
#if nsrs_COMPILER_MSVC_VER >= 1900
# undef nsrs_CPP11_OR_GREATER
# define nsrs_CPP11_OR_GREATER 1
#endif
#define nsrs_CPP11_90 (nsrs_CPP11_OR_GREATER_ || nsrs_COMPILER_MSVC_VER >= 1500)
#define nsrs_CPP11_100 (nsrs_CPP11_OR_GREATER_ || nsrs_COMPILER_MSVC_VER >= 1600)
#define nsrs_CPP11_110 (nsrs_CPP11_OR_GREATER_ || nsrs_COMPILER_MSVC_VER >= 1700)
#define nsrs_CPP11_120 (nsrs_CPP11_OR_GREATER_ || nsrs_COMPILER_MSVC_VER >= 1800)
#define nsrs_CPP11_140 (nsrs_CPP11_OR_GREATER_ || nsrs_COMPILER_MSVC_VER >= 1900)
#define nsrs_CPP14_000 (nsrs_CPP14_OR_GREATER)
#define nsrs_CPP17_000 (nsrs_CPP17_OR_GREATER)
#define nsrs_CPP20_000 (nsrs_CPP20_OR_GREATER)
// half-open range [lo..hi):
#define nsrs_BETWEEN( v, lo, hi ) ( (lo) <= (v) && (v) < (hi) )
// Presence of C++11 language features:
#define nsrs_HAVE_CONSTEXPR_11 nsrs_CPP11_140
#define nsrs_HAVE_IS_DEFAULT nsrs_CPP11_140
#define nsrs_HAVE_IS_DELETE nsrs_CPP11_140
#define nsrs_HAVE_NOEXCEPT nsrs_CPP11_140
#define nsrs_HAVE_NULLPTR nsrs_CPP11_100
// Presence of C++14 language features:
#define nsrs_HAVE_CONSTEXPR_14 nsrs_CPP14_000
// Presence of C++17 language features:
// no tag
// Presence of C++20 language features:
#define nsrs_HAVE_NO_UNIQUE_ADDRESS nsrs_CPP20_000
#define nsrs_HAVE_NO_UNIQUE_ADDRESS_MSVC (nsrs_COMPILER_MSVC_VER >= 1929)
// Presence of C++ library features:
// no tag
// Compiler warning suppression:
#if defined(__clang__)
# pragma clang diagnostic push
# pragma clang diagnostic ignored "-Wundef"
# define nsrs_RESTORE_WARNINGS() _Pragma( "clang diagnostic pop" )
#elif defined __GNUC__
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wundef"
# define nsrs_RESTORE_WARNINGS() _Pragma( "GCC diagnostic pop" )
#elif nsrs_COMPILER_MSVC_VERSION >= 140
# define nsrs_DISABLE_MSVC_WARNINGS(codes) __pragma(warning(push)) __pragma(warning(disable: codes))
# define nsrs_RESTORE_WARNINGS() __pragma(warning(pop ))
// Suppress the following MSVC warnings:
// - C4345: initialization behavior changed
//
// Suppress the following MSVC GSL warnings:
// - C26439, gsl::f.6 : special function 'function' can be declared 'noexcept'
// - C26440, gsl::f.6 : function 'function' can be declared 'noexcept'
// - C26472, gsl::t.1 : don't use a static_cast for arithmetic conversions;
// use brace initialization, gsl::narrow_cast or gsl::narrow
// - C26473: gsl::t.1 : don't cast between pointer types where the source type and the target type are the same
// - C26481: gsl::b.1 : don't use pointer arithmetic. Use span instead
// - C26490: gsl::t.1 : don't use reinterpret_cast
nsrs_DISABLE_MSVC_WARNINGS( 4345 26439 26440 26472 26473 26481 26490 )
#else
# define nsrs_RESTORE_WARNINGS() /*empty*/
#endif
// C++ feature usage:
#if nsrs_HAVE_CONSTEXPR_11
# define nsrs_constexpr constexpr
#else
# define nsrs_constexpr /*constexpr*/
#endif
#if nsrs_HAVE_CONSTEXPR_14
# define nsrs_constexpr14 constexpr
#else
# define nsrs_constexpr14 /*constexpr*/
#endif
#if nsrs_HAVE_NOEXCEPT
# define nsrs_noexcept noexcept
# define nsrs_noexcept_op noexcept
#else
# define nsrs_noexcept /*noexcept*/
# define nsrs_noexcept_op(expr) /*noexcept(expr)*/
#endif
#if nsrs_HAVE_NULLPTR
# define nsrs_nullptr nullptr
#else
# define nsrs_nullptr NULL
#endif
#if nsrs_HAVE_NO_UNIQUE_ADDRESS
# define nsrs_NO_UNIQUE_ADDRESS [[no_unique_address]]
#elif nsrs_HAVE_NO_UNIQUE_ADDRESS_MSVC
# define nsrs_NO_UNIQUE_ADDRESS [[msvc::no_unique_address]]
#else
# define nsrs_NO_UNIQUE_ADDRESS /*[[no_unique_address]]*/
#endif
// Method enabling
#if nsrs_CPP11_OR_GREATER
#define nsrs_REQUIRES_0(...) \
template< bool B = (__VA_ARGS__), typename std::enable_if<B, int>::type = 0 >
#define nsrs_REQUIRES_T(...) \
, typename std::enable_if< (__VA_ARGS__), int >::type = 0
#endif
// includes:
#include <cassert>
#include <iterator>
#include <utility>
// additional includes:
#if ! nsrs_CPP11_OR_GREATER
# include <algorithm> // std::swap() until C++11
#endif
namespace nonstd { namespace ring_span_lite {
// type traits C++11:
namespace std11 {
#if nsrs_CPP11_OR_GREATER
using std::move;
#else
template< typename T > T const & move( T const & t ) { return t; }
#endif
#if nsrs_CPP11_OR_GREATER
using std::true_type;
using std::false_type;
using std::integral_constant;
#else
template< typename T, T v >
struct integral_constant
{
typedef T value_type;
enum { value = v };
operator value_type() const { return value; }
};
typedef integral_constant<bool, true> true_type;
typedef integral_constant<bool, false> false_type;
#endif // nsrs_CPP11_OR_GREATER
template< bool B, class T, class F >
struct conditional { typedef T type; };
template< class T, class F >
struct conditional<false, T, F> { typedef F type; };
} // namespace std11
// type traits C++17:
namespace std17 {
template< bool V >
struct bool_constant : std11::integral_constant<bool, V> {};
#if nsrs_CPP17_OR_GREATER
using std::is_swappable;
using std::is_nothrow_swappable;
#elif nsrs_CPP11_OR_GREATER
namespace detail {
using std::swap;
struct is_swappable
{
template< typename T, typename = decltype( swap( std::declval<T&>(), std::declval<T&>() ) ) >
static std::true_type test( int );
template< typename >
static std::false_type test(...);
};
struct is_nothrow_swappable
{
// wrap noexcept(epr) in separate function as work-around for VC140 (VS2015):
template< typename T >
static constexpr bool test()
{
return noexcept( swap( std::declval<T&>(), std::declval<T&>() ) );
}
template< typename T >
static auto test( int ) -> std::integral_constant<bool, test<T>()>{}
template< typename >
static std::false_type test(...);
};
} // namespace detail
// is [nothow] swappable:
template< typename T >
struct is_swappable : decltype( detail::is_swappable::test<T>(0) ){};
template< typename T >
struct is_nothrow_swappable : decltype( detail::is_nothrow_swappable::test<T>(0) ){};
#endif // nsrs_CPP17_OR_GREATER
} // namespace std17
//
// element extraction policies:
//
template< class T >
struct null_popper
{
typedef void return_type;
void operator()( T & ) const nsrs_noexcept {}
};
template< class T >
struct default_popper
{
typedef T return_type;
T operator()( T & t ) const
{
return std11::move( t );
}
};
template< class T >
struct copy_popper
{
typedef T return_type;
#if nsrs_CPP11_OR_GREATER
# if nsrs_RING_SPAN_LITE_EXTENSION
copy_popper( T t )
: m_copy( std::move(t) )
{}
# else
copy_popper( T && t )
: m_copy( std::move(t) )
{}
# endif
#else // C++98, no extension
copy_popper( T const & t )
: m_copy( t )
{}
#endif
T operator()( T & t ) const
{
using std::swap;
T result( m_copy ); swap( t, result ); return result;
}
T m_copy;
};
// forward-declare iterator:
namespace detail {
template< class, bool >
class ring_iterator;
template< typename T >
bool is_power_of_2( T n )
{
return n > 0 && (n & (n - 1)) == 0;
}
} // namespace detail
//
// ring span:
//
template
<
class T
, class Popper = default_popper<T>
#if nsrs_RING_SPAN_LITE_EXTENSION
, bool CapacityIsPowerOf2 = false
#endif
>
class ring_span
#if nsrs_CONFIG_POPPER_EMPTY_BASE_CLASS
: private Popper
#endif
{
public:
typedef T value_type;
typedef T * pointer;
typedef T & reference;
typedef T const & const_reference;
typedef std::size_t size_type;
#if nsrs_RING_SPAN_LITE_EXTENSION
typedef ring_span< T, Popper, CapacityIsPowerOf2 > type;
#else
typedef ring_span< T, Popper > type;
#endif
typedef detail::ring_iterator< type, false > iterator;
typedef detail::ring_iterator< type, true > const_iterator;
#if nsrs_RING_SPAN_LITE_EXTENSION
typedef std::reverse_iterator<iterator > reverse_iterator;
typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
#endif
// construction:
template< class ContiguousIterator >
ring_span(
ContiguousIterator begin
, ContiguousIterator end
, Popper popper = Popper()
) nsrs_noexcept
#if nsrs_CONFIG_POPPER_EMPTY_BASE_CLASS
: Popper ( std11::move( popper ) )
, m_data ( &* begin )
, m_size ( 0 )
, m_capacity ( static_cast<size_type>( end - begin ) )
, m_front_idx( 0 )
#else
: m_data ( &* begin )
, m_size ( 0 )
, m_capacity ( static_cast<size_type>( end - begin ) )
, m_front_idx( 0 )
, m_popper ( std11::move( popper ) )
#endif
{
#if nsrs_RING_SPAN_LITE_EXTENSION
assert( !CapacityIsPowerOf2 || detail::is_power_of_2( m_capacity ) );
#endif
}
template< class ContiguousIterator >
ring_span(
ContiguousIterator begin
, ContiguousIterator end
, ContiguousIterator first
, size_type size
, Popper popper = Popper()
) nsrs_noexcept
#if nsrs_CONFIG_POPPER_EMPTY_BASE_CLASS
: Popper ( std11::move( popper ) )
, m_data ( &* begin )
, m_size ( size )
, m_capacity ( static_cast<size_type>( end - begin ) )
, m_front_idx( static_cast<size_type>( first - begin ) )
#else
: m_data ( &* begin )
, m_size ( size )
, m_capacity ( static_cast<size_type>( end - begin ) )
, m_front_idx( static_cast<size_type>( first - begin ) )
, m_popper ( std11::move( popper ) )
#endif
{
assert( m_size <= m_capacity );
#if nsrs_RING_SPAN_LITE_EXTENSION
assert( !CapacityIsPowerOf2 || detail::is_power_of_2( m_capacity ) );
#endif
}
#if nsrs_HAVE_IS_DEFAULT
ring_span( ring_span && ) = default;
ring_span& operator=( ring_span && ) = default;
#else
private:
ring_span( ring_span const & );
ring_span & operator=( ring_span const & );
public:
#endif
// observers:
bool empty() const nsrs_noexcept
{
return m_size == 0;
}
bool full() const nsrs_noexcept
{
return m_size == m_capacity;
}
size_type size() const nsrs_noexcept
{
return m_size;
}
size_type capacity() const nsrs_noexcept
{
return m_capacity;
}
// element access:
#if nsrs_RING_SPAN_LITE_EXTENSION
reference operator[]( size_type idx ) nsrs_noexcept
{
assert( idx < m_size ); return at_(idx);
}
const_reference operator[]( size_type idx ) const nsrs_noexcept
{
assert( idx < m_size ); return at_(idx);
}
#endif
reference front() nsrs_noexcept
{
return *begin();
}
const_reference front() const nsrs_noexcept
{
return *begin();
}
reference back() nsrs_noexcept
{
return *(--end());
}
const_reference back() const nsrs_noexcept
{
return *(--end());
}
// iteration:
iterator begin() nsrs_noexcept
{
return iterator( 0, this );
}
const_iterator begin() const nsrs_noexcept
{
return cbegin();
}
const_iterator cbegin() const nsrs_noexcept
{
return const_iterator( 0, this );
}
iterator end() nsrs_noexcept
{
return iterator( size(), this );
}
const_iterator end() const nsrs_noexcept
{
return cend();
}
const_iterator cend() const nsrs_noexcept
{
return const_iterator( size(), this );
}
#if nsrs_RING_SPAN_LITE_EXTENSION
reverse_iterator rbegin() nsrs_noexcept
{
return reverse_iterator( end() );
}
reverse_iterator rend() nsrs_noexcept
{
return reverse_iterator( begin() );
}
const_reverse_iterator rbegin() const nsrs_noexcept
{
return crbegin();
}
const_reverse_iterator rend() const nsrs_noexcept
{
return crend();
}
const_reverse_iterator crbegin() const nsrs_noexcept
{
return const_reverse_iterator( cend() );
}
const_reverse_iterator crend() const nsrs_noexcept
{
return const_reverse_iterator(cbegin());
}
#endif
// element insertion, extraction:
typename Popper::return_type pop_front()
{
assert( ! empty() );
reference element = front_();
increment_front_();
#if nsrs_CONFIG_POPPER_EMPTY_BASE_CLASS
return this->operator()( element );
#else
return m_popper( element );
#endif
}
#if nsrs_RING_SPAN_LITE_EXTENSION
typename Popper::return_type pop_back()
{
assert( ! empty() );
reference element = back_();
decrement_back_();
#if nsrs_CONFIG_POPPER_EMPTY_BASE_CLASS
return this->operator()( element );
#else
return m_popper( element );
#endif
}
#endif
#if nsrs_CPP11_OR_GREATER
nsrs_REQUIRES_0( std::is_copy_assignable<T>::value )
void push_back( value_type const & value) noexcept( std::is_nothrow_copy_assignable<T>::value )
#else
void push_back( value_type const & value )
#endif
{
if ( full() ) increment_front_and_back_();
else increment_back_();
back_() = value;
}
#if nsrs_CPP11_OR_GREATER
nsrs_REQUIRES_0( std::is_move_assignable<T>::value )
void push_back( value_type && value ) noexcept( std::is_nothrow_move_assignable<T>::value )
{
if ( full() ) increment_front_and_back_();
else increment_back_();
back_() = std::move( value );
}
template< typename... Args
nsrs_REQUIRES_T(
std::is_constructible<T, Args&&...>::value
&& std::is_move_assignable<T>::value
)
>
void emplace_back( Args &&... args ) noexcept
(
std::is_nothrow_constructible<T, Args...>::value
&& std::is_nothrow_move_assignable<T>::value
)
{
if ( full() ) increment_front_and_back_();
else increment_back_();
back_() = T( std::forward<Args>(args)...);
}
#endif
#if nsrs_RING_SPAN_LITE_EXTENSION
#if nsrs_CPP11_OR_GREATER
nsrs_REQUIRES_0( std::is_copy_assignable<T>::value )
void push_front( T const & value ) noexcept(( std::is_nothrow_copy_assignable<T>::value ))
#else
void push_front( T const & value )
#endif
{
if ( full() ) decrement_front_and_back_();
else decrement_front_();
front_() = value;
}
#if nsrs_CPP11_OR_GREATER
nsrs_REQUIRES_0( std::is_move_assignable<T>::value )
void push_front( T && value ) noexcept(( std::is_nothrow_move_assignable<T>::value ))
{
if ( full() ) decrement_front_and_back_();
else decrement_front_();
front_() = std::move(value);
}
template< typename... Args
nsrs_REQUIRES_T(
std::is_constructible<T, Args&&...>::value
&& std::is_move_assignable<T>::value
)
>
void emplace_front( Args&&... args ) noexcept
(
std::is_nothrow_constructible<T, Args...>::value
&& std::is_nothrow_move_assignable<T>::value
)
{
if ( full() ) decrement_front_and_back_();
else decrement_front_();
front_() = T( std::forward<Args>(args)...);
}
#endif
#endif // nsrs_RING_SPAN_LITE_EXTENSION
// swap:
void swap( type & rhs )
#if nsrs_CPP11_OR_GREATER
noexcept(
std17::is_nothrow_swappable<Popper>::value
)
#endif
{
using std::swap;
swap( m_data , rhs.m_data );
swap( m_size , rhs.m_size );
swap( m_capacity , rhs.m_capacity );
swap( m_front_idx, rhs.m_front_idx );
#if !nsrs_RING_SPAN_LITE_EXTENSION
swap( m_popper , rhs.m_popper );
#endif
}
private:
friend class detail::ring_iterator<ring_span, true >; // const_iterator;
friend class detail::ring_iterator<ring_span, false>; // iterator;
#if nsrs_RING_SPAN_LITE_EXTENSION
size_type normalize_( size_type const idx, std11::true_type ) const nsrs_noexcept
{
return idx & (m_capacity - 1);
}
size_type normalize_( size_type const idx, std11::false_type ) const nsrs_noexcept
{
return idx % m_capacity;
}
size_type normalize_( size_type const idx ) const nsrs_noexcept
{
return normalize_( idx, std17::bool_constant<CapacityIsPowerOf2>() );
}
#else
size_type normalize_( size_type const idx ) const nsrs_noexcept
{
return idx % m_capacity;
}
#endif // nsrs_RING_SPAN_LITE_EXTENSION
reference at_( size_type idx ) nsrs_noexcept
{
return m_data[ normalize_(m_front_idx + idx) ];
}
const_reference at_( size_type idx ) const nsrs_noexcept
{
return m_data[ normalize_(m_front_idx + idx) ];
}
reference front_() nsrs_noexcept
{
return *( m_data + m_front_idx );
}
const_reference front_() const nsrs_noexcept
{
return *( m_data + m_front_idx );
}
reference back_() nsrs_noexcept
{
return *( m_data + normalize_(m_front_idx + m_size - 1) );
}
const_reference back_() const nsrs_noexcept
{
return *( m_data + normalize_(m_front_idx + m_size - 1) );
}
void increment_front_() nsrs_noexcept
{
m_front_idx = normalize_(m_front_idx + 1);
--m_size;
}
void decrement_front_() nsrs_noexcept
{
m_front_idx = normalize_(m_front_idx + m_capacity - 1);
++m_size;
}
void increment_back_() nsrs_noexcept
{
++m_size;
}
void decrement_back_() nsrs_noexcept
{
--m_size;
}
void increment_front_and_back_() nsrs_noexcept
{
m_front_idx = normalize_( m_front_idx + 1 );
}
void decrement_front_and_back_() nsrs_noexcept
{
m_front_idx = normalize_( m_front_idx + m_capacity - 1 );
}
private:
pointer m_data;
size_type m_size;
size_type m_capacity;
size_type m_front_idx;
#if !nsrs_CONFIG_POPPER_EMPTY_BASE_CLASS
nsrs_NO_UNIQUE_ADDRESS Popper m_popper;
#endif
};
// swap:
template< class T, class Popper >
inline void swap( ring_span<T,Popper> & lhs, ring_span<T,Popper> & rhs ) nsrs_noexcept_op( nsrs_noexcept_op( lhs.swap(rhs) ) )
{
lhs.swap(rhs);
}
namespace detail {
//
// ring iterator:
//
#if 0
template< class RS, bool is_const >
class ring_iterator : public std::iterator
<
std::random_access_iterator_tag
, typename std11::conditional<is_const, const typename RS::value_type, typename RS::value_type>::type
>
#endif
template< class RS, bool is_const >
class ring_iterator
{
public:
typedef ring_iterator<RS, is_const> type;
typedef std::ptrdiff_t difference_type;
typedef typename RS::value_type value_type;
typedef typename std11::conditional<is_const, const value_type, value_type>::type * pointer;
typedef typename std11::conditional<is_const, const value_type, value_type>::type & reference;
typedef std::random_access_iterator_tag iterator_category;
#if nsrs_CPP11_OR_GREATER
ring_iterator() = default;
#else
ring_iterator() : m_idx(), m_rs() {}
#endif
#if nsrs_RING_SPAN_LITE_EXTENSION
// conversion to const iterator:
operator ring_iterator<RS, true>() const nsrs_noexcept
{
return ring_iterator<RS, true>( m_idx, m_rs );
}
#endif
// access content:
reference operator*() const nsrs_noexcept
{
return m_rs->at_( m_idx );
}
// see issue #21:
pointer operator->() const nsrs_noexcept
{
return & m_rs->at_( m_idx );
}
// advance iterator:
type & operator++() nsrs_noexcept
{
++m_idx; return *this;
}
type operator++( int ) nsrs_noexcept
{
type r(*this); ++*this; return r;
}
type & operator--() nsrs_noexcept
{
--m_idx; return *this;
}
type operator--( int ) nsrs_noexcept
{
type r(*this); --*this; return r;
}
#if defined(__clang__) || defined(__GNUC__)