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span.hpp
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//
// span for C++98 and later.
// Based on http://wg21.link/p0122r7
// For more information see https://github.com/martinmoene/span-lite
//
// Copyright 2018-2019 Martin Moene
//
// 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)
#ifndef NONSTD_SPAN_HPP_INCLUDED
#define NONSTD_SPAN_HPP_INCLUDED
#define span_lite_MAJOR 0
#define span_lite_MINOR 8
#define span_lite_PATCH 1
#define span_lite_VERSION span_STRINGIFY(span_lite_MAJOR) "." span_STRINGIFY(span_lite_MINOR) "." span_STRINGIFY(span_lite_PATCH)
#define span_STRINGIFY( x ) span_STRINGIFY_( x )
#define span_STRINGIFY_( x ) #x
// span configuration:
#define span_SPAN_DEFAULT 0
#define span_SPAN_NONSTD 1
#define span_SPAN_STD 2
// tweak header support:
#ifdef __has_include
# if __has_include(<nonstd/span.tweak.hpp>)
# include <nonstd/span.tweak.hpp>
# endif
#define span_HAVE_TWEAK_HEADER 1
#else
#define span_HAVE_TWEAK_HEADER 0
//# pragma message("span.hpp: Note: Tweak header not supported.")
#endif
// span selection and configuration:
#define span_HAVE( feature ) ( span_HAVE_##feature )
#ifndef span_CONFIG_SELECT_SPAN
# define span_CONFIG_SELECT_SPAN ( span_HAVE_STD_SPAN ? span_SPAN_STD : span_SPAN_NONSTD )
#endif
#ifndef span_CONFIG_EXTENT_TYPE
# define span_CONFIG_EXTENT_TYPE std::size_t
#endif
#ifndef span_CONFIG_SIZE_TYPE
# define span_CONFIG_SIZE_TYPE std::size_t
#endif
#ifdef span_CONFIG_INDEX_TYPE
# error `span_CONFIG_INDEX_TYPE` is deprecated since v0.7.0; it is replaced by `span_CONFIG_SIZE_TYPE`.
#endif
// span configuration (features):
#ifndef span_FEATURE_WITH_CONTAINER
#ifdef span_FEATURE_WITH_CONTAINER_TO_STD
# define span_FEATURE_WITH_CONTAINER span_IN_STD( span_FEATURE_WITH_CONTAINER_TO_STD )
#else
# define span_FEATURE_WITH_CONTAINER 0
#endif
#endif
#ifndef span_FEATURE_CONSTRUCTION_FROM_STDARRAY_ELEMENT_TYPE
# define span_FEATURE_CONSTRUCTION_FROM_STDARRAY_ELEMENT_TYPE 0
#endif
#ifndef span_FEATURE_MEMBER_AT
# define span_FEATURE_MEMBER_AT 0
#endif
#ifndef span_FEATURE_MEMBER_BACK_FRONT
# define span_FEATURE_MEMBER_BACK_FRONT 1
#endif
#ifndef span_FEATURE_MEMBER_CALL_OPERATOR
# define span_FEATURE_MEMBER_CALL_OPERATOR 0
#endif
#ifndef span_FEATURE_MEMBER_SWAP
# define span_FEATURE_MEMBER_SWAP 0
#endif
#ifndef span_FEATURE_NON_MEMBER_FIRST_LAST_SUB
# define span_FEATURE_NON_MEMBER_FIRST_LAST_SUB 0
#endif
#ifndef span_FEATURE_COMPARISON
# define span_FEATURE_COMPARISON 0 // Note: C++20 does not provide comparison
#endif
#ifndef span_FEATURE_SAME
# define span_FEATURE_SAME 0
#endif
#if span_FEATURE_SAME && !span_FEATURE_COMPARISON
# error `span_FEATURE_SAME` requires `span_FEATURE_COMPARISON`
#endif
#ifndef span_FEATURE_MAKE_SPAN
#ifdef span_FEATURE_MAKE_SPAN_TO_STD
# define span_FEATURE_MAKE_SPAN span_IN_STD( span_FEATURE_MAKE_SPAN_TO_STD )
#else
# define span_FEATURE_MAKE_SPAN 0
#endif
#endif
#ifndef span_FEATURE_BYTE_SPAN
# define span_FEATURE_BYTE_SPAN 0
#endif
// Control presence of exception handling (try and auto discover):
#ifndef span_CONFIG_NO_EXCEPTIONS
# if defined(__cpp_exceptions) || defined(__EXCEPTIONS) || defined(_CPPUNWIND)
# define span_CONFIG_NO_EXCEPTIONS 0
# else
# define span_CONFIG_NO_EXCEPTIONS 1
# undef span_CONFIG_CONTRACT_VIOLATION_THROWS
# undef span_CONFIG_CONTRACT_VIOLATION_TERMINATES
# define span_CONFIG_CONTRACT_VIOLATION_THROWS 0
# define span_CONFIG_CONTRACT_VIOLATION_TERMINATES 1
# endif
#endif
// Control pre- and postcondition violation behaviour:
#if defined( span_CONFIG_CONTRACT_LEVEL_ON )
# define span_CONFIG_CONTRACT_LEVEL_MASK 0x11
#elif defined( span_CONFIG_CONTRACT_LEVEL_OFF )
# define span_CONFIG_CONTRACT_LEVEL_MASK 0x00
#elif defined( span_CONFIG_CONTRACT_LEVEL_EXPECTS_ONLY )
# define span_CONFIG_CONTRACT_LEVEL_MASK 0x01
#elif defined( span_CONFIG_CONTRACT_LEVEL_ENSURES_ONLY )
# define span_CONFIG_CONTRACT_LEVEL_MASK 0x10
#else
# define span_CONFIG_CONTRACT_LEVEL_MASK 0x11
#endif
#if defined( span_CONFIG_CONTRACT_VIOLATION_THROWS )
# define span_CONFIG_CONTRACT_VIOLATION_THROWS_V span_CONFIG_CONTRACT_VIOLATION_THROWS
#else
# define span_CONFIG_CONTRACT_VIOLATION_THROWS_V 0
#endif
#if defined( span_CONFIG_CONTRACT_VIOLATION_THROWS ) && span_CONFIG_CONTRACT_VIOLATION_THROWS && \
defined( span_CONFIG_CONTRACT_VIOLATION_TERMINATES ) && span_CONFIG_CONTRACT_VIOLATION_TERMINATES
# error Please define none or one of span_CONFIG_CONTRACT_VIOLATION_THROWS and span_CONFIG_CONTRACT_VIOLATION_TERMINATES to 1, but not both.
#endif
// C++ language version detection (C++20 is speculative):
// Note: VC14.0/1900 (VS2015) lacks too much from C++14.
#ifndef span_CPLUSPLUS
# if defined(_MSVC_LANG ) && !defined(__clang__)
# define span_CPLUSPLUS (_MSC_VER == 1900 ? 201103L : _MSVC_LANG )
# else
# define span_CPLUSPLUS __cplusplus
# endif
#endif
#define span_CPP98_OR_GREATER ( span_CPLUSPLUS >= 199711L )
#define span_CPP11_OR_GREATER ( span_CPLUSPLUS >= 201103L )
#define span_CPP14_OR_GREATER ( span_CPLUSPLUS >= 201402L )
#define span_CPP17_OR_GREATER ( span_CPLUSPLUS >= 201703L )
#define span_CPP20_OR_GREATER ( span_CPLUSPLUS >= 202000L )
// C++ language version (represent 98 as 3):
#define span_CPLUSPLUS_V ( span_CPLUSPLUS / 100 - (span_CPLUSPLUS > 200000 ? 2000 : 1994) )
#define span_IN_STD( v ) ( ((v) == 98 ? 3 : (v)) >= span_CPLUSPLUS_V )
#define span_CONFIG( feature ) ( span_CONFIG_##feature )
#define span_FEATURE( feature ) ( span_FEATURE_##feature )
#define span_FEATURE_TO_STD( feature ) ( span_IN_STD( span_FEATURE( feature##_TO_STD ) ) )
// Use C++20 std::span if available and requested:
#if span_CPP20_OR_GREATER && defined(__has_include )
# if __has_include( <span> )
# define span_HAVE_STD_SPAN 1
# else
# define span_HAVE_STD_SPAN 0
# endif
#else
# define span_HAVE_STD_SPAN 0
#endif
#define span_USES_STD_SPAN ( (span_CONFIG_SELECT_SPAN == span_SPAN_STD) || ((span_CONFIG_SELECT_SPAN == span_SPAN_DEFAULT) && span_HAVE_STD_SPAN) )
//
// Use C++20 std::span:
//
#if span_USES_STD_SPAN
#include <span>
namespace nonstd {
using std::span;
// Note: C++20 does not provide comparison
// using std::operator==;
// using std::operator!=;
// using std::operator<;
// using std::operator<=;
// using std::operator>;
// using std::operator>=;
} // namespace nonstd
#else // span_USES_STD_SPAN
#include <algorithm>
// Compiler versions:
//
// MSVC++ 6.0 _MSC_VER == 1200 span_COMPILER_MSVC_VERSION == 60 (Visual Studio 6.0)
// MSVC++ 7.0 _MSC_VER == 1300 span_COMPILER_MSVC_VERSION == 70 (Visual Studio .NET 2002)
// MSVC++ 7.1 _MSC_VER == 1310 span_COMPILER_MSVC_VERSION == 71 (Visual Studio .NET 2003)
// MSVC++ 8.0 _MSC_VER == 1400 span_COMPILER_MSVC_VERSION == 80 (Visual Studio 2005)
// MSVC++ 9.0 _MSC_VER == 1500 span_COMPILER_MSVC_VERSION == 90 (Visual Studio 2008)
// MSVC++ 10.0 _MSC_VER == 1600 span_COMPILER_MSVC_VERSION == 100 (Visual Studio 2010)
// MSVC++ 11.0 _MSC_VER == 1700 span_COMPILER_MSVC_VERSION == 110 (Visual Studio 2012)
// MSVC++ 12.0 _MSC_VER == 1800 span_COMPILER_MSVC_VERSION == 120 (Visual Studio 2013)
// MSVC++ 14.0 _MSC_VER == 1900 span_COMPILER_MSVC_VERSION == 140 (Visual Studio 2015)
// MSVC++ 14.1 _MSC_VER >= 1910 span_COMPILER_MSVC_VERSION == 141 (Visual Studio 2017)
// MSVC++ 14.2 _MSC_VER >= 1920 span_COMPILER_MSVC_VERSION == 142 (Visual Studio 2019)
#if defined(_MSC_VER ) && !defined(__clang__)
# define span_COMPILER_MSVC_VER (_MSC_VER )
# define span_COMPILER_MSVC_VERSION (_MSC_VER / 10 - 10 * ( 5 + (_MSC_VER < 1900 ) ) )
#else
# define span_COMPILER_MSVC_VER 0
# define span_COMPILER_MSVC_VERSION 0
#endif
#define span_COMPILER_VERSION( major, minor, patch ) ( 10 * ( 10 * (major) + (minor) ) + (patch) )
#if defined(__clang__)
# define span_COMPILER_CLANG_VERSION span_COMPILER_VERSION(__clang_major__, __clang_minor__, __clang_patchlevel__)
#else
# define span_COMPILER_CLANG_VERSION 0
#endif
#if defined(__GNUC__) && !defined(__clang__)
# define span_COMPILER_GNUC_VERSION span_COMPILER_VERSION(__GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__)
#else
# define span_COMPILER_GNUC_VERSION 0
#endif
// half-open range [lo..hi):
#define span_BETWEEN( v, lo, hi ) ( (lo) <= (v) && (v) < (hi) )
// Compiler warning suppression:
#if defined(__clang__)
# pragma clang diagnostic push
# pragma clang diagnostic ignored "-Wundef"
# pragma clang diagnostic ignored "-Wmismatched-tags"
# define span_RESTORE_WARNINGS() _Pragma( "clang diagnostic pop" )
#elif defined __GNUC__
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wundef"
# define span_RESTORE_WARNINGS() _Pragma( "GCC diagnostic pop" )
#elif span_COMPILER_MSVC_VER >= 1900
# define span_DISABLE_MSVC_WARNINGS(codes) __pragma(warning(push)) __pragma(warning(disable: codes))
# define span_RESTORE_WARNINGS() __pragma(warning(pop ))
// 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
span_DISABLE_MSVC_WARNINGS( 26439 26440 26472 26473 26481 26490 )
#else
# define span_RESTORE_WARNINGS() /*empty*/
#endif
// Presence of language and library features:
#ifdef _HAS_CPP0X
# define span_HAS_CPP0X _HAS_CPP0X
#else
# define span_HAS_CPP0X 0
#endif
#define span_CPP11_80 (span_CPP11_OR_GREATER || span_COMPILER_MSVC_VER >= 1400)
#define span_CPP11_90 (span_CPP11_OR_GREATER || span_COMPILER_MSVC_VER >= 1500)
#define span_CPP11_100 (span_CPP11_OR_GREATER || span_COMPILER_MSVC_VER >= 1600)
#define span_CPP11_110 (span_CPP11_OR_GREATER || span_COMPILER_MSVC_VER >= 1700)
#define span_CPP11_120 (span_CPP11_OR_GREATER || span_COMPILER_MSVC_VER >= 1800)
#define span_CPP11_140 (span_CPP11_OR_GREATER || span_COMPILER_MSVC_VER >= 1900)
#define span_CPP14_000 (span_CPP14_OR_GREATER)
#define span_CPP14_120 (span_CPP14_OR_GREATER || span_COMPILER_MSVC_VER >= 1800)
#define span_CPP14_140 (span_CPP14_OR_GREATER || span_COMPILER_MSVC_VER >= 1900)
#define span_CPP17_000 (span_CPP17_OR_GREATER)
// Presence of C++11 language features:
#define span_HAVE_ALIAS_TEMPLATE span_CPP11_140
#define span_HAVE_AUTO span_CPP11_100
#define span_HAVE_CONSTEXPR_11 span_CPP11_140
#define span_HAVE_DEFAULT_FUNCTION_TEMPLATE_ARG span_CPP11_120
#define span_HAVE_EXPLICIT_CONVERSION span_CPP11_140
#define span_HAVE_INITIALIZER_LIST span_CPP11_120
#define span_HAVE_IS_DEFAULT span_CPP11_140
#define span_HAVE_IS_DELETE span_CPP11_140
#define span_HAVE_NOEXCEPT span_CPP11_140
#define span_HAVE_NULLPTR span_CPP11_100
#define span_HAVE_STATIC_ASSERT span_CPP11_100
// Presence of C++14 language features:
#define span_HAVE_CONSTEXPR_14 span_CPP14_000
// Presence of C++17 language features:
#define span_HAVE_DEPRECATED span_CPP17_000
#define span_HAVE_NODISCARD span_CPP17_000
#define span_HAVE_NORETURN span_CPP17_000
// MSVC: template parameter deduction guides since Visual Studio 2017 v15.7
#define span_HAVE_DEDUCTION_GUIDES (span_CPP17_OR_GREATER && ! span_BETWEEN( span_COMPILER_MSVC_VER, 1, 1913 ))
// Presence of C++ library features:
#define span_HAVE_ADDRESSOF span_CPP17_000
#define span_HAVE_ARRAY span_CPP11_110
#define span_HAVE_BYTE span_CPP17_000
#define span_HAVE_CONDITIONAL span_CPP11_120
#define span_HAVE_CONTAINER_DATA_METHOD (span_CPP11_140 || ( span_COMPILER_MSVC_VER >= 1500 && span_HAS_CPP0X ))
#define span_HAVE_DATA span_CPP17_000
#define span_HAVE_LONGLONG span_CPP11_80
#define span_HAVE_REMOVE_CONST span_CPP11_110
#define span_HAVE_SNPRINTF span_CPP11_140
#define span_HAVE_STRUCT_BINDING span_CPP11_120
#define span_HAVE_TYPE_TRAITS span_CPP11_90
// Presence of byte-lite:
#ifdef NONSTD_BYTE_LITE_HPP
# define span_HAVE_NONSTD_BYTE 1
#else
# define span_HAVE_NONSTD_BYTE 0
#endif
// C++ feature usage:
#if span_HAVE_ADDRESSOF
# define span_ADDRESSOF(x) std::addressof(x)
#else
# define span_ADDRESSOF(x) (&x)
#endif
#if span_HAVE_CONSTEXPR_11
# define span_constexpr constexpr
#else
# define span_constexpr /*span_constexpr*/
#endif
#if span_HAVE_CONSTEXPR_14
# define span_constexpr14 constexpr
#else
# define span_constexpr14 /*span_constexpr*/
#endif
#if span_HAVE_EXPLICIT_CONVERSION
# define span_explicit explicit
#else
# define span_explicit /*explicit*/
#endif
#if span_HAVE_IS_DELETE
# define span_is_delete = delete
#else
# define span_is_delete
#endif
#if span_HAVE_IS_DELETE
# define span_is_delete_access public
#else
# define span_is_delete_access private
#endif
#if span_HAVE_NOEXCEPT && ! span_CONFIG_CONTRACT_VIOLATION_THROWS_V
# define span_noexcept noexcept
#else
# define span_noexcept /*noexcept*/
#endif
#if span_HAVE_NULLPTR
# define span_nullptr nullptr
#else
# define span_nullptr NULL
#endif
#if span_HAVE_DEPRECATED
# define span_deprecated(msg) [[deprecated(msg)]]
#else
# define span_deprecated(msg) /*[[deprecated]]*/
#endif
#if span_HAVE_NODISCARD
# define span_nodiscard [[nodiscard]]
#else
# define span_nodiscard /*[[nodiscard]]*/
#endif
#if span_HAVE_NORETURN
# define span_noreturn [[noreturn]]
#else
# define span_noreturn /*[[noreturn]]*/
#endif
// Other features:
#define span_HAVE_CONSTRAINED_SPAN_CONTAINER_CTOR span_HAVE_DEFAULT_FUNCTION_TEMPLATE_ARG
// Additional includes:
#if span_HAVE( ADDRESSOF )
# include <memory>
#endif
#if span_HAVE( ARRAY )
# include <array>
#endif
#if span_HAVE( BYTE )
# include <cstddef>
#endif
#if span_HAVE( DATA )
# include <iterator> // for std::data(), std::size()
#endif
#if span_HAVE( TYPE_TRAITS )
# include <type_traits>
#endif
#if ! span_HAVE( CONSTRAINED_SPAN_CONTAINER_CTOR )
# include <vector>
#endif
#if span_FEATURE( MEMBER_AT ) > 1
# include <cstdio>
#endif
#if ! span_CONFIG( NO_EXCEPTIONS )
# include <stdexcept>
#endif
// Contract violation
#define span_ELIDE_CONTRACT_EXPECTS ( 0 == ( span_CONFIG_CONTRACT_LEVEL_MASK & 0x01 ) )
#define span_ELIDE_CONTRACT_ENSURES ( 0 == ( span_CONFIG_CONTRACT_LEVEL_MASK & 0x10 ) )
#if span_ELIDE_CONTRACT_EXPECTS
# define span_constexpr_exp span_constexpr
# define span_EXPECTS( cond ) /* Expect elided */
#else
# define span_constexpr_exp span_constexpr14
# define span_EXPECTS( cond ) span_CONTRACT_CHECK( "Precondition", cond )
#endif
#if span_ELIDE_CONTRACT_ENSURES
# define span_constexpr_ens span_constexpr
# define span_ENSURES( cond ) /* Ensures elided */
#else
# define span_constexpr_ens span_constexpr14
# define span_ENSURES( cond ) span_CONTRACT_CHECK( "Postcondition", cond )
#endif
#define span_CONTRACT_CHECK( type, cond ) \
cond ? static_cast< void >( 0 ) \
: nonstd::span_lite::detail::report_contract_violation( span_LOCATION( __FILE__, __LINE__ ) ": " type " violation." )
#ifdef __GNUG__
# define span_LOCATION( file, line ) file ":" span_STRINGIFY( line )
#else
# define span_LOCATION( file, line ) file "(" span_STRINGIFY( line ) ")"
#endif
// Method enabling
#define span_REQUIRES_0(VA) \
template< bool B = (VA), typename std::enable_if<B, int>::type = 0 >
# if span_BETWEEN( span_COMPILER_MSVC_VERSION, 1, 140 )
// VS 2013 and earlier seem to have trouble with SFINAE for default non-type arguments
# define span_REQUIRES_T(VA) \
, typename = typename std::enable_if< ( VA ), nonstd::span_lite::detail::enabler >::type
# else
# define span_REQUIRES_T(VA) \
, typename std::enable_if< (VA), int >::type = 0
# endif
#define span_REQUIRES_R(R, VA) \
typename std::enable_if< (VA), R>::type
#define span_REQUIRES_A(VA) \
, typename std::enable_if< (VA), void*>::type = nullptr
namespace nonstd {
namespace span_lite {
// [views.constants], constants
typedef span_CONFIG_EXTENT_TYPE extent_t;
typedef span_CONFIG_SIZE_TYPE size_t;
span_constexpr const extent_t dynamic_extent = static_cast<extent_t>( -1 );
template< class T, extent_t Extent = dynamic_extent >
class span;
// Tag to select span constructor taking a container (prevent ms-gsl warning C26426):
struct with_container_t { span_constexpr with_container_t() span_noexcept {} };
const span_constexpr with_container_t with_container;
// C++11 emulation:
namespace std11 {
#if span_HAVE( REMOVE_CONST )
using std::remove_cv;
using std::remove_const;
using std::remove_volatile;
#else
template< class T > struct remove_const { typedef T type; };
template< class T > struct remove_const< T const > { typedef T type; };
template< class T > struct remove_volatile { typedef T type; };
template< class T > struct remove_volatile< T volatile > { typedef T type; };
template< class T >
struct remove_cv
{
typedef typename std11::remove_volatile< typename std11::remove_const< T >::type >::type type;
};
#endif // span_HAVE( REMOVE_CONST )
#if span_HAVE( TYPE_TRAITS )
using std::is_same;
using std::is_signed;
using std::integral_constant;
using std::true_type;
using std::false_type;
using std::remove_reference;
#else
template< class T, T v > struct integral_constant { enum { value = v }; };
typedef integral_constant< bool, true > true_type;
typedef integral_constant< bool, false > false_type;
template< class T, class U > struct is_same : false_type{};
template< class T > struct is_same<T, T> : true_type{};
template< typename T > struct is_signed : false_type {};
template<> struct is_signed<signed char> : true_type {};
template<> struct is_signed<signed int > : true_type {};
template<> struct is_signed<signed long> : true_type {};
#endif
} // namespace std11
// C++17 emulation:
namespace std17 {
template< bool v > struct bool_constant : std11::integral_constant<bool, v>{};
#if span_CPP11_120
template< class...>
using void_t = void;
#endif
#if span_HAVE( DATA )
using std::data;
using std::size;
#elif span_HAVE_CONSTRAINED_SPAN_CONTAINER_CTOR
template< typename T, std::size_t N >
inline span_constexpr auto size( const T(&)[N] ) span_noexcept -> size_t
{
return N;
}
template< typename C >
inline span_constexpr auto size( C const & cont ) -> decltype( cont.size() )
{
return cont.size();
}
template< typename T, std::size_t N >
inline span_constexpr auto data( T(&arr)[N] ) span_noexcept -> T*
{
return &arr[0];
}
template< typename C >
inline span_constexpr auto data( C & cont ) -> decltype( cont.data() )
{
return cont.data();
}
template< typename C >
inline span_constexpr auto data( C const & cont ) -> decltype( cont.data() )
{
return cont.data();
}
template< typename E >
inline span_constexpr auto data( std::initializer_list<E> il ) span_noexcept -> E const *
{
return il.begin();
}
#endif // span_HAVE( DATA )
#if span_HAVE( BYTE )
using std::byte;
#elif span_HAVE( NONSTD_BYTE )
using nonstd::byte;
#endif
} // namespace std17
// C++20 emulation:
namespace std20 {
#if span_HAVE( DEDUCTION_GUIDES )
template< class T >
using iter_reference_t = decltype( *std::declval<T&>() );
#endif
} // namespace std20
// Implementation details:
namespace detail {
/*enum*/ struct enabler{};
template< typename T >
bool is_positive( T x )
{
return std11::is_signed<T>::value ? x >= 0 : true;
}
#if span_HAVE( TYPE_TRAITS )
template< class Q >
struct is_span_oracle : std::false_type{};
template< class T, span_CONFIG_EXTENT_TYPE Extent >
struct is_span_oracle< span<T, Extent> > : std::true_type{};
template< class Q >
struct is_span : is_span_oracle< typename std::remove_cv<Q>::type >{};
template< class Q >
struct is_std_array_oracle : std::false_type{};
#if span_HAVE( ARRAY )
template< class T, std::size_t Extent >
struct is_std_array_oracle< std::array<T, Extent> > : std::true_type{};
#endif
template< class Q >
struct is_std_array : is_std_array_oracle< typename std::remove_cv<Q>::type >{};
template< class Q >
struct is_array : std::false_type {};
template< class T >
struct is_array<T[]> : std::true_type {};
template< class T, std::size_t N >
struct is_array<T[N]> : std::true_type {};
#if span_CPP11_140 && ! span_BETWEEN( span_COMPILER_GNUC_VERSION, 1, 500 )
template< class, class = void >
struct has_size_and_data : std::false_type{};
template< class C >
struct has_size_and_data
<
C, std17::void_t<
decltype( std17::size(std::declval<C>()) ),
decltype( std17::data(std::declval<C>()) ) >
> : std::true_type{};
template< class, class, class = void >
struct is_compatible_element : std::false_type {};
template< class C, class E >
struct is_compatible_element
<
C, E, std17::void_t<
decltype( std17::data(std::declval<C>()) ) >
> : std::is_convertible< typename std::remove_pointer<decltype( std17::data( std::declval<C&>() ) )>::type(*)[], E(*)[] >{};
template< class C >
struct is_container : std17::bool_constant
<
! is_span< C >::value
&& ! is_array< C >::value
&& ! is_std_array< C >::value
&& has_size_and_data< C >::value
>{};
template< class C, class E >
struct is_compatible_container : std17::bool_constant
<
is_container<C>::value
&& is_compatible_element<C,E>::value
>{};
#else // span_CPP11_140
template<
class C, class E
span_REQUIRES_T((
! is_span< C >::value
&& ! is_array< C >::value
&& ! is_std_array< C >::value
&& ( std::is_convertible< typename std::remove_pointer<decltype( std17::data( std::declval<C&>() ) )>::type(*)[], E(*)[] >::value)
// && has_size_and_data< C >::value
))
, class = decltype( std17::size(std::declval<C>()) )
, class = decltype( std17::data(std::declval<C>()) )
>
struct is_compatible_container : std::true_type{};
#endif // span_CPP11_140
#endif // span_HAVE( TYPE_TRAITS )
#if ! span_CONFIG( NO_EXCEPTIONS )
#if span_FEATURE( MEMBER_AT ) > 1
// format index and size:
#if defined(__clang__)
# pragma clang diagnostic ignored "-Wlong-long"
#elif defined __GNUC__
# pragma GCC diagnostic ignored "-Wformat=ll"
# pragma GCC diagnostic ignored "-Wlong-long"
#endif
inline void throw_out_of_range( size_t idx, size_t size )
{
const char fmt[] = "span::at(): index '%lli' is out of range [0..%lli)";
char buffer[ 2 * 20 + sizeof fmt ];
sprintf( buffer, fmt, static_cast<long long>(idx), static_cast<long long>(size) );
throw std::out_of_range( buffer );
}
#else // MEMBER_AT
inline void throw_out_of_range( size_t /*idx*/, size_t /*size*/ )
{
throw std::out_of_range( "span::at(): index outside span" );
}
#endif // MEMBER_AT
#endif // NO_EXCEPTIONS
#if span_CONFIG( CONTRACT_VIOLATION_THROWS_V )
struct contract_violation : std::logic_error
{
explicit contract_violation( char const * const message )
: std::logic_error( message )
{}
};
inline void report_contract_violation( char const * msg )
{
throw contract_violation( msg );
}
#else // span_CONFIG( CONTRACT_VIOLATION_THROWS_V )
span_noreturn inline void report_contract_violation( char const * /*msg*/ ) span_noexcept
{
std::terminate();
}
#endif // span_CONFIG( CONTRACT_VIOLATION_THROWS_V )
} // namespace detail
// Prevent signed-unsigned mismatch:
#define span_sizeof(T) static_cast<extent_t>( sizeof(T) )
template< class T >
inline span_constexpr size_t to_size( T size )
{
return static_cast<size_t>( size );
}
//
// [views.span] - A view over a contiguous, single-dimension sequence of objects
//
template< class T, extent_t Extent /*= dynamic_extent*/ >
class span
{
public:
// constants and types
typedef T element_type;
typedef typename std11::remove_cv< T >::type value_type;
typedef T & reference;
typedef T * pointer;
typedef T const * const_pointer;
typedef T const & const_reference;
typedef size_t size_type;
typedef extent_t extent_type;
typedef pointer iterator;
typedef const_pointer const_iterator;
typedef std::ptrdiff_t difference_type;
typedef std::reverse_iterator< iterator > reverse_iterator;
typedef std::reverse_iterator< const_iterator > const_reverse_iterator;
// static constexpr extent_type extent = Extent;
enum { extent = Extent };
// 26.7.3.2 Constructors, copy, and assignment [span.cons]
#if span_HAVE( DEFAULT_FUNCTION_TEMPLATE_ARG )
span_REQUIRES_0(
( Extent == 0 ) ||
( Extent == dynamic_extent )
)
#endif
span_constexpr span() span_noexcept
: data_( span_nullptr )
, size_( 0 )
{
// span_EXPECTS( data() == span_nullptr );
// span_EXPECTS( size() == 0 );
}
span_constexpr_exp span( pointer ptr, size_type count )
: data_( ptr )
, size_( count )
{
span_EXPECTS(
( ptr == span_nullptr && count == 0 ) ||
( ptr != span_nullptr && detail::is_positive( count ) )
);
}
span_constexpr_exp span( pointer firstElem, pointer lastElem )
: data_( firstElem )
, size_( to_size( std::distance( firstElem, lastElem ) ) )
{
span_EXPECTS(
std::distance( firstElem, lastElem ) >= 0
);
}
template< std::size_t N
#if span_HAVE( DEFAULT_FUNCTION_TEMPLATE_ARG )
span_REQUIRES_T((
(Extent == dynamic_extent || Extent == static_cast<extent_t>(N))
&& std::is_convertible< value_type(*)[], element_type(*)[] >::value
))
#endif
>
span_constexpr span( element_type ( &arr )[ N ] ) span_noexcept
: data_( span_ADDRESSOF( arr[0] ) )
, size_( N )
{}
#if span_HAVE( ARRAY )
template< std::size_t N
# if span_HAVE( DEFAULT_FUNCTION_TEMPLATE_ARG )
span_REQUIRES_T((
(Extent == dynamic_extent || Extent == static_cast<extent_t>(N))
&& std::is_convertible< value_type(*)[], element_type(*)[] >::value
))
# endif
>
# if span_FEATURE( CONSTRUCTION_FROM_STDARRAY_ELEMENT_TYPE )
span_constexpr span( std::array< element_type, N > & arr ) span_noexcept
# else
span_constexpr span( std::array< value_type, N > & arr ) span_noexcept
# endif
: data_( arr.data() )
, size_( to_size( arr.size() ) )
{}
template< std::size_t N
# if span_HAVE( DEFAULT_FUNCTION_TEMPLATE_ARG )
span_REQUIRES_T((
(Extent == dynamic_extent || Extent == static_cast<extent_t>(N))
&& std::is_convertible< value_type(*)[], element_type(*)[] >::value
))
# endif
>
span_constexpr span( std::array< value_type, N> const & arr ) span_noexcept
: data_( arr.data() )
, size_( to_size( arr.size() ) )
{}
#endif // span_HAVE( ARRAY )
#if span_HAVE( CONSTRAINED_SPAN_CONTAINER_CTOR )
template< class Container
span_REQUIRES_T((
detail::is_compatible_container< Container, element_type >::value
))
>
span_constexpr span( Container & cont )
: data_( std17::data( cont ) )
, size_( to_size( std17::size( cont ) ) )
{}
template< class Container
span_REQUIRES_T((
std::is_const< element_type >::value
&& detail::is_compatible_container< Container, element_type >::value
))
>
span_constexpr span( Container const & cont )
: data_( std17::data( cont ) )
, size_( to_size( std17::size( cont ) ) )
{}
#endif // span_HAVE( CONSTRAINED_SPAN_CONTAINER_CTOR )
#if span_FEATURE( WITH_CONTAINER )
template< class Container >
span_constexpr span( with_container_t, Container & cont )
: data_( cont.size() == 0 ? span_nullptr : span_ADDRESSOF( cont[0] ) )
, size_( to_size( cont.size() ) )
{}
template< class Container >
span_constexpr span( with_container_t, Container const & cont )
: data_( cont.size() == 0 ? span_nullptr : const_cast<pointer>( span_ADDRESSOF( cont[0] ) ) )
, size_( to_size( cont.size() ) )
{}
#endif
#if span_HAVE( IS_DEFAULT )
span_constexpr span( span const & other ) span_noexcept = default;
~span() span_noexcept = default;
span_constexpr14 span & operator=( span const & other ) span_noexcept = default;
#else
span_constexpr span( span const & other ) span_noexcept
: data_( other.data_ )