Add boost/core/string_view.hpp

This commit is contained in:
Peter Dimov
2021-10-04 16:49:46 +03:00
parent 5e382efa84
commit 95924b1329
4 changed files with 799 additions and 0 deletions

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[/
Copyright 2021 Peter Dimov
Distributed under the Boost Software License, Version 1.0.
https://boost.org/LICENSE_1_0.txt
]
[section:string_view string_view]
[simplesect Authors]
* Peter Dimov
[endsimplesect]
[section Header <boost/core/string_view.hpp>]
The header `<boost/core/string_view.hpp>` defines `boost::core::string_view`,
a portable and interoperable implementation of `std::string_view`.
Unlike `boost::string_view`, `boost::core::string_view` has implicit
conversions from and to `std::string_view`, which allows Boost libraries that
support C++11/C++14 to use it in interfaces without forcing users to forgo the
use of `std::string_view` in their code.
[section Synopsis]
``
namespace boost
{
namespace core
{
template<class Ch> class basic_string_view
{
private:
Ch const* data_;
std::size_t size_;
public:
// types
typedef std::char_traits<Ch> traits_type;
typedef Ch value_type;
typedef Ch* pointer;
typedef Ch const* const_pointer;
typedef Ch& reference;
typedef Ch const& const_reference;
typedef Ch const* const_iterator;
typedef const_iterator iterator;
typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
typedef const_reverse_iterator reverse_iterator;
typedef std::size_t size_type;
typedef std::ptrdiff_t difference_type;
// npos
static constexpr size_type npos = static_cast<size_type>( -1 );
public:
// construction and assignment
constexpr basic_string_view() noexcept;
constexpr basic_string_view( basic_string_view const& ) noexcept = default;
constexpr basic_string_view& operator=( basic_string_view const& ) noexcept & = default;
constexpr basic_string_view( Ch const* str ) noexcept;
constexpr basic_string_view( Ch const* str, size_type len ) noexcept;
constexpr basic_string_view( Ch const* begin, Ch const* end ) noexcept;
template<class A> basic_string_view(std::basic_string<Ch, std::char_traits<Ch>, A> const& str ) noexcept;
basic_string_view(std::basic_string_view<Ch, std::char_traits<Ch>> const& str ) noexcept;
// iterator support
constexpr const_iterator begin() const noexcept;
constexpr const_iterator end() const noexcept;
constexpr const_iterator cbegin() const noexcept;
constexpr const_iterator cend() const noexcept;
constexpr const_reverse_iterator rbegin() const noexcept;
constexpr const_reverse_iterator rend() const noexcept;
constexpr const_reverse_iterator crbegin() const noexcept;
constexpr const_reverse_iterator crend() const noexcept;
// capacity
constexpr size_type size() const noexcept;
constexpr size_type length() const noexcept;
constexpr size_type max_size() const noexcept;
constexpr bool empty() const noexcept;
// element access
constexpr const_reference operator[]( size_type pos ) const noexcept;
constexpr const_reference at( size_type pos ) const;
constexpr const_reference front() const noexcept;
constexpr const_reference back() const noexcept;
constexpr const_pointer data() const noexcept;
// modifiers
constexpr void remove_prefix( size_type n ) noexcept;
constexpr void remove_suffix( size_type n ) noexcept;
constexpr void swap( basic_string_view& s ) noexcept;
// string operations
constexpr size_type copy( Ch* s, size_type n, size_type pos = 0 ) const;
constexpr basic_string_view substr( size_type pos = 0, size_type n = npos ) const;
constexpr int compare( basic_string_view s ) const noexcept;
constexpr int compare( size_type pos1, size_type n1, basic_string_view s ) const;
constexpr int compare( size_type pos1, size_type n1, basic_string_view s, size_type pos2, size_type n2 ) const;
constexpr int compare( Ch const* s ) const;
constexpr int compare( size_type pos1, size_type n1, Ch const* s ) const;
constexpr int compare( size_type pos1, size_type n1, Ch const* s, size_type n2 ) const;
constexpr bool starts_with( basic_string_view x ) const noexcept;
constexpr bool starts_with( Ch x ) const noexcept;
constexpr bool starts_with( Ch const* x ) const;
constexpr bool ends_with( basic_string_view x ) const noexcept;
constexpr bool ends_with( Ch x ) const noexcept;
constexpr bool ends_with( Ch const* x ) const;
// searching
constexpr size_type find( basic_string_view s, size_type pos = 0 ) const noexcept;
constexpr size_type find( Ch c, size_type pos = 0 ) const noexcept;
constexpr size_type find( Ch const* s, size_type pos, size_type n ) const;
constexpr size_type find( Ch const* s, size_type pos = 0 ) const;
constexpr size_type rfind( basic_string_view s, size_type pos = npos ) const noexcept;
constexpr size_type rfind( Ch c, size_type pos = npos ) const noexcept;
constexpr size_type rfind( Ch const* s, size_type pos, size_type n ) const;
constexpr size_type rfind( Ch const* s, size_type pos = npos ) const;
constexpr size_type find_first_of( basic_string_view s, size_type pos = 0 ) const noexcept;
constexpr size_type find_first_of( Ch c, size_type pos = 0 ) const noexcept;
constexpr size_type find_first_of( Ch const* s, size_type pos, size_type n ) const;
constexpr size_type find_first_of( Ch const* s, size_type pos = 0 ) const;
constexpr size_type find_last_of( basic_string_view s, size_type pos = npos ) const noexcept;
constexpr size_type find_last_of( Ch c, size_type pos = npos ) const noexcept;
constexpr size_type find_last_of( Ch const* s, size_type pos, size_type n ) const;
constexpr size_type find_last_of( Ch const* s, size_type pos = npos ) const;
constexpr size_type find_first_not_of( basic_string_view s, size_type pos = 0 ) const noexcept;
constexpr size_type find_first_not_of( Ch c, size_type pos = 0 ) const noexcept;
constexpr size_type find_first_not_of( Ch const* s, size_type pos, size_type n ) const;
constexpr size_type find_first_not_of( Ch const* s, size_type pos = 0 ) const;
constexpr size_type find_last_not_of( basic_string_view s, size_type pos = npos ) const noexcept;
constexpr size_type find_last_not_of( Ch c, size_type pos = npos ) const noexcept;
constexpr size_type find_last_not_of( Ch const* s, size_type pos, size_type n ) const;
constexpr size_type find_last_not_of( Ch const* s, size_type pos = npos ) const;
};
typedef basic_string_view<char> string_view;
typedef basic_string_view<wchar_t> wstring_view;
typedef basic_string_view<char16_t> u16string_view;
typedef basic_string_view<char32_t> u32string_view;
typedef basic_string_view<char8_t> u8string_view;
} // namespace core
} // namespace boost
``
[endsect]
[section Construction]
[section constexpr basic_string_view() noexcept;]
* *Ensures:* `data() == 0`, `size() == 0`.
[endsect]
[endsect]
[endsect]

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#ifndef BOOST_CORE_STRING_VIEW_HPP_INCLUDED
#define BOOST_CORE_STRING_VIEW_HPP_INCLUDED
// MS compatible compilers support #pragma once
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif
// boost::core::basic_string_view<Ch>
//
// Copyright 2021 Peter Dimov
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
#include <boost/assert.hpp>
#include <boost/throw_exception.hpp>
#include <boost/config.hpp>
#include <string>
#include <algorithm>
#include <utility>
#include <stdexcept>
#include <cstddef>
#include <cstring>
#if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
# include <string_view>
#endif
namespace boost
{
namespace core
{
template<class Ch> class basic_string_view
{
private:
Ch const* p_;
std::size_t n_;
public:
// types
typedef std::char_traits<Ch> traits_type;
typedef Ch value_type;
typedef Ch* pointer;
typedef Ch const* const_pointer;
typedef Ch& reference;
typedef Ch const& const_reference;
typedef Ch const* const_iterator;
typedef const_iterator iterator;
typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
typedef const_reverse_iterator reverse_iterator;
typedef std::size_t size_type;
typedef std::ptrdiff_t difference_type;
// npos
BOOST_STATIC_CONSTEXPR size_type npos = static_cast<size_type>( -1 );
public:
// construction and assignment
BOOST_CONSTEXPR basic_string_view() BOOST_NOEXCEPT: p_(), n_()
{
}
BOOST_CONSTEXPR basic_string_view( Ch const* str ) BOOST_NOEXCEPT: p_( str ), n_( traits_type::length( str ) )
{
}
BOOST_CONSTEXPR basic_string_view( Ch const* str, size_type len ) BOOST_NOEXCEPT: p_( str ), n_( len )
{
}
BOOST_CXX14_CONSTEXPR basic_string_view( Ch const* begin, Ch const* end ) BOOST_NOEXCEPT: p_( begin ), n_( end - begin )
{
BOOST_ASSERT( end - begin >= 0 );
}
template<class A> basic_string_view( std::basic_string<Ch, std::char_traits<Ch>, A> const& str ) BOOST_NOEXCEPT: p_( str.data() ), n_( str.size() )
{
}
#if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
basic_string_view( std::basic_string_view<Ch, std::char_traits<Ch> > const& str ) BOOST_NOEXCEPT: p_( str.data() ), n_( str.size() )
{
}
#endif
// BOOST_CONSTEXPR basic_string_view& operator=( basic_string_view const& ) BOOST_NOEXCEPT & = default;
// iterator support
BOOST_CONSTEXPR const_iterator begin() const BOOST_NOEXCEPT
{
return p_;
}
BOOST_CONSTEXPR const_iterator end() const BOOST_NOEXCEPT
{
return p_ + n_;
}
BOOST_CONSTEXPR const_iterator cbegin() const BOOST_NOEXCEPT
{
return p_;
}
BOOST_CONSTEXPR const_iterator cend() const BOOST_NOEXCEPT
{
return p_ + n_;
}
BOOST_CONSTEXPR const_reverse_iterator rbegin() const BOOST_NOEXCEPT
{
return const_reverse_iterator( begin() );
}
BOOST_CONSTEXPR const_reverse_iterator rend() const BOOST_NOEXCEPT
{
return const_reverse_iterator( end() );
}
BOOST_CONSTEXPR const_reverse_iterator crbegin() const BOOST_NOEXCEPT
{
return const_reverse_iterator( begin() );
}
BOOST_CONSTEXPR const_reverse_iterator crend() const BOOST_NOEXCEPT
{
return const_reverse_iterator( end() );
}
// capacity
BOOST_CONSTEXPR size_type size() const BOOST_NOEXCEPT
{
return n_;
}
BOOST_CONSTEXPR size_type length() const BOOST_NOEXCEPT
{
return n_;
}
BOOST_CONSTEXPR size_type max_size() const BOOST_NOEXCEPT
{
return npos / sizeof( Ch );
}
BOOST_CONSTEXPR bool empty() const BOOST_NOEXCEPT
{
return n_ == 0;
}
// element access
BOOST_CONSTEXPR const_reference operator[]( size_type pos ) const BOOST_NOEXCEPT
{
BOOST_ASSERT( pos < size() );
return p_[ pos ];
}
BOOST_CONSTEXPR const_reference at( size_type pos ) const
{
if( pos >= size() )
{
boost::throw_exception( std::out_of_range( "basic_string_view::at" ), BOOST_CURRENT_LOCATION );
}
return p_[ pos ];
}
BOOST_CONSTEXPR const_reference front() const BOOST_NOEXCEPT
{
BOOST_ASSERT( !empty() );
return p_[ 0 ];
}
BOOST_CONSTEXPR const_reference back() const BOOST_NOEXCEPT
{
BOOST_ASSERT( !empty() );
return p_[ n_ - 1 ];
}
BOOST_CONSTEXPR const_pointer data() const BOOST_NOEXCEPT
{
return p_;
}
// modifiers
BOOST_CXX14_CONSTEXPR void remove_prefix( size_type n ) BOOST_NOEXCEPT
{
BOOST_ASSERT( n <= size() );
p_ += n;
n_ -= n;
}
BOOST_CXX14_CONSTEXPR void remove_suffix( size_type n ) BOOST_NOEXCEPT
{
BOOST_ASSERT( n <= size() );
n_ -= n;
}
BOOST_CXX14_CONSTEXPR void swap( basic_string_view& s ) BOOST_NOEXCEPT
{
std::swap( p_, s.p_ );
std::swap( n_, s.n_ );
}
// string operations
BOOST_CONSTEXPR size_type copy( Ch* s, size_type n, size_type pos = 0 ) const
{
if( pos > size() )
{
boost::throw_exception( std::out_of_range( "basic_string_view::copy" ), BOOST_CURRENT_LOCATION );
}
std::size_t rlen = std::min( n, size() - pos );
traits_type::copy( s, data() + pos, rlen );
return rlen;
}
BOOST_CONSTEXPR basic_string_view substr( size_type pos = 0, size_type n = npos ) const
{
if( pos > size() )
{
boost::throw_exception( std::out_of_range( "basic_string_view::substr" ), BOOST_CURRENT_LOCATION );
}
std::size_t rlen = std::min( n, size() - pos );
return basic_string_view( data() + pos, rlen );
}
// compare
BOOST_CONSTEXPR int compare( basic_string_view str ) const BOOST_NOEXCEPT
{
std::size_t rlen = std::min( size(), str.size() );
int cmp = traits_type::compare( data(), str.data(), rlen );
if( cmp != 0 ) return cmp;
if( size() == str.size() ) return 0;
return size() < str.size()? -1: +1;
}
BOOST_CONSTEXPR int compare( size_type pos1, size_type n1, basic_string_view str ) const
{
return substr( pos1, n1 ).compare( str );
}
BOOST_CONSTEXPR int compare( size_type pos1, size_type n1, basic_string_view str, size_type pos2, size_type n2 ) const
{
return substr( pos1, n1 ).compare( str.substr( pos2, n2 ) );
}
BOOST_CONSTEXPR int compare( Ch const* s ) const BOOST_NOEXCEPT
{
return compare( basic_string_view( s ) );
}
BOOST_CONSTEXPR int compare( size_type pos1, size_type n1, Ch const* s ) const
{
return substr( pos1, n1 ).compare( basic_string_view( s ) );
}
BOOST_CONSTEXPR int compare( size_type pos1, size_type n1, Ch const* s, size_type n2 ) const
{
return substr( pos1, n1 ).compare( basic_string_view( s, n2 ) );
}
// starts_with
BOOST_CONSTEXPR bool starts_with( basic_string_view x ) const BOOST_NOEXCEPT
{
return substr( 0, x.size() ) == x;
}
BOOST_CONSTEXPR bool starts_with( Ch x ) const BOOST_NOEXCEPT
{
return !empty() && front() == x;
}
BOOST_CONSTEXPR bool starts_with( Ch const* x ) const
{
return starts_with( basic_string_view( x ) );
}
// ends_with
BOOST_CONSTEXPR bool ends_with( basic_string_view x ) const BOOST_NOEXCEPT
{
return size() >= x.size() && compare( size() - x.size(), npos, x ) == 0;
}
BOOST_CONSTEXPR bool ends_with( Ch x ) const BOOST_NOEXCEPT
{
return !empty() && back() == x;
}
BOOST_CONSTEXPR bool ends_with( Ch const* x ) const
{
return ends_with( basic_string_view( x ) );
}
// find
BOOST_CONSTEXPR size_type find( basic_string_view str, size_type pos = 0 ) const BOOST_NOEXCEPT
{
return find( str.data(), pos, str.size() );
}
BOOST_CONSTEXPR size_type find( Ch c, size_type pos = 0 ) const BOOST_NOEXCEPT
{
if( pos >= size() ) return npos;
Ch const* r = traits_type::find( data() + pos, size() - pos, c );
return r? r - data(): npos;
}
BOOST_CONSTEXPR size_type find( Ch const* s, size_type pos, size_type n ) const BOOST_NOEXCEPT
{
if( pos + n > size() ) return npos;
if( n == 0 ) return pos;
Ch const* p = data() + pos;
Ch const* last = data() + size();
for( ;; )
{
p = traits_type::find( p, last - p, s[0] );
if( p == 0 ) break;
if( last - p < n ) break;
if( traits_type::compare( p, s, n ) == 0 ) return p - data();
++p;
}
return npos;
}
BOOST_CONSTEXPR size_type find( Ch const* s, size_type pos = 0 ) const BOOST_NOEXCEPT
{
return find( s, pos, traits_type::length( s ) );
}
// rfind
BOOST_CONSTEXPR size_type rfind( basic_string_view str, size_type pos = npos ) const BOOST_NOEXCEPT
{
return rfind( str.data(), pos, str.size() );
}
BOOST_CONSTEXPR size_type rfind( Ch c, size_type pos = npos ) const BOOST_NOEXCEPT
{
if( pos > size() )
{
pos = size();
}
const_reverse_iterator r = std::find( rbegin() + pos, rend(), c );
return r == rend()? npos: size() - 1 - ( r - rbegin() );
}
BOOST_CONSTEXPR size_type rfind( Ch const* s, size_type pos, size_type n ) const BOOST_NOEXCEPT
{
if( n > size() ) return npos;
if( pos > size() - n )
{
pos = size() - n;
}
if( n == 0 ) return pos;
for( ;; )
{
size_type xpos = rfind( s[0], pos );
if( xpos == npos ) return npos;
if( traits_type::compare( data() + xpos, s, n ) == 0 ) return xpos;
if( xpos == 0 ) return npos;
pos = xpos - 1;
}
}
BOOST_CONSTEXPR size_type rfind( Ch const* s, size_type pos = npos ) const BOOST_NOEXCEPT
{
return rfind( s, pos, traits_type::length( s ) );
}
// find_first_of
BOOST_CONSTEXPR size_type find_first_of( basic_string_view str, size_type pos = 0 ) const BOOST_NOEXCEPT
{
for( std::size_t i = pos; i < n_; ++i )
{
if( str.contains( p_[ i ] ) ) return i;
}
return npos;
}
BOOST_CONSTEXPR size_type find_first_of( Ch c, size_type pos = 0 ) const BOOST_NOEXCEPT
{
return find( c, pos );
}
BOOST_CONSTEXPR size_type find_first_of( Ch const* s, size_type pos, size_type n ) const BOOST_NOEXCEPT
{
return find_first_of( basic_string_view( s, n ), pos );
}
BOOST_CONSTEXPR size_type find_first_of( Ch const* s, size_type pos = 0 ) const BOOST_NOEXCEPT
{
return find_first_of( basic_string_view( s ), pos );
}
// find_last_of
BOOST_CONSTEXPR size_type find_last_of( basic_string_view str, size_type pos = npos ) const BOOST_NOEXCEPT
{
if( pos > size() )
{
pos = size();
}
for( std::size_t i = pos; i > 0; --i )
{
if( str.contains( p_[ i - 1 ] ) ) return i - 1;
}
return npos;
}
BOOST_CONSTEXPR size_type find_last_of( Ch c, size_type pos = npos ) const BOOST_NOEXCEPT
{
return rfind( c, pos );
}
BOOST_CONSTEXPR size_type find_last_of( Ch const* s, size_type pos, size_type n ) const BOOST_NOEXCEPT
{
return find_last_of( basic_string_view( s, n ), pos );
}
BOOST_CONSTEXPR size_type find_last_of( Ch const* s, size_type pos = npos ) const BOOST_NOEXCEPT
{
return find_last_of( basic_string_view( s ), pos );
}
// find_first_not_of
BOOST_CONSTEXPR size_type find_first_not_of( basic_string_view str, size_type pos = 0 ) const BOOST_NOEXCEPT
{
for( std::size_t i = pos; i < n_; ++i )
{
if( !str.contains( p_[ i ] ) ) return i;
}
return npos;
}
BOOST_CONSTEXPR size_type find_first_not_of( Ch c, size_type pos = 0 ) const BOOST_NOEXCEPT
{
for( std::size_t i = pos; i < n_; ++i )
{
if( p_[ i ] != c ) return i;
}
return npos;
}
BOOST_CONSTEXPR size_type find_first_not_of( Ch const* s, size_type pos, size_type n ) const BOOST_NOEXCEPT
{
return find_first_not_of( basic_string_view( s, n ), pos );
}
BOOST_CONSTEXPR size_type find_first_not_of( Ch const* s, size_type pos = 0 ) const BOOST_NOEXCEPT
{
return find_first_not_of( basic_string_view( s ), pos );
}
// find_last_not_of
BOOST_CONSTEXPR size_type find_last_not_of( basic_string_view str, size_type pos = npos ) const BOOST_NOEXCEPT
{
if( pos > size() )
{
pos = size();
}
for( std::size_t i = pos; i > 0; --i )
{
if( !str.contains( p_[ i - 1 ] ) ) return i - 1;
}
return npos;
}
BOOST_CONSTEXPR size_type find_last_not_of( Ch c, size_type pos = npos ) const BOOST_NOEXCEPT
{
if( pos > size() )
{
pos = size();
}
for( std::size_t i = pos; i > 0; --i )
{
if( p_[ i - 1 ] != c ) return i - 1;
}
return npos;
}
BOOST_CONSTEXPR size_type find_last_not_of( Ch const* s, size_type pos, size_type n ) const BOOST_NOEXCEPT
{
return find_last_not_of( basic_string_view( s, n ), pos );
}
BOOST_CONSTEXPR size_type find_last_not_of( Ch const* s, size_type pos = npos ) const BOOST_NOEXCEPT
{
return find_last_not_of( basic_string_view( s ), pos );
}
// contains
BOOST_CONSTEXPR bool contains( basic_string_view sv ) const BOOST_NOEXCEPT
{
return find( sv ) != npos;
}
BOOST_CONSTEXPR bool contains( Ch c ) const BOOST_NOEXCEPT
{
return traits_type::find( data(), size(), c ) == 0;
}
BOOST_CONSTEXPR bool contains( Ch const* s ) const BOOST_NOEXCEPT
{
return find( s ) != npos;
}
};
#if defined(BOOST_NO_CXX17_INLINE_VARIABLES)
template<class Ch> std::size_t const basic_string_view<Ch>::npos;
#endif

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@ -247,5 +247,7 @@ run bit_endian_test.cpp ;
run type_name_test.cpp ;
run sv_types_test.cpp ;
use-project /boost/core/swap : ./swap ;
build-project ./swap ;

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// Copyright 2021 Peter Dimov
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
#include <boost/core/string_view.hpp>
#include <boost/core/lightweight_test.hpp>
#include <boost/core/lightweight_test_trait.hpp>
#include <boost/core/is_same.hpp>
#include <iterator>
struct Ch
{
};
int main()
{
using boost::core::is_same;
typedef boost::core::basic_string_view<Ch> ch_string_view;
BOOST_TEST_TRAIT_TRUE((is_same< ch_string_view::traits_type, std::char_traits<Ch> >));
BOOST_TEST_TRAIT_TRUE((is_same< ch_string_view::value_type, Ch >));
BOOST_TEST_TRAIT_TRUE((is_same< ch_string_view::pointer, Ch* >));
BOOST_TEST_TRAIT_TRUE((is_same< ch_string_view::const_pointer, Ch const* >));
BOOST_TEST_TRAIT_TRUE((is_same< ch_string_view::reference, Ch& >));
BOOST_TEST_TRAIT_TRUE((is_same< ch_string_view::const_reference, Ch const& >));
BOOST_TEST_TRAIT_TRUE((is_same< ch_string_view::iterator, ch_string_view::const_iterator >));
BOOST_TEST_TRAIT_TRUE((is_same< std::iterator_traits<ch_string_view::iterator>::iterator_category, std::random_access_iterator_tag >));
BOOST_TEST_TRAIT_TRUE((is_same< ch_string_view::reverse_iterator, ch_string_view::const_reverse_iterator >));
BOOST_TEST_TRAIT_TRUE((is_same< ch_string_view::reverse_iterator, std::reverse_iterator<ch_string_view::iterator> >));
BOOST_TEST_TRAIT_TRUE((is_same< ch_string_view::size_type, std::size_t >));
BOOST_TEST_TRAIT_TRUE((is_same< ch_string_view::difference_type, std::ptrdiff_t >));
BOOST_TEST_EQ(ch_string_view::npos, static_cast<std::size_t>(-1));
BOOST_TEST_TRAIT_TRUE((is_same< boost::core::string_view, boost::core::basic_string_view<char> >));
BOOST_TEST_TRAIT_TRUE((is_same< boost::core::wstring_view, boost::core::basic_string_view<wchar_t> >));
#if !defined(BOOST_NO_CXX11_CHAR16_T)
BOOST_TEST_TRAIT_TRUE((is_same< boost::core::u16string_view, boost::core::basic_string_view<char16_t> >));
#endif
#if !defined(BOOST_NO_CXX11_CHAR32_T)
BOOST_TEST_TRAIT_TRUE((is_same< boost::core::u32string_view, boost::core::basic_string_view<char32_t> >));
#endif
#if defined(__cpp_char8_t) && __cpp_char8_t >= 201811L
BOOST_TEST_TRAIT_TRUE((is_same< boost::core::u8string_view, boost::core::basic_string_view<char8_t> >));
#endif
return boost::report_errors();
}