Merge pull request #861 from JordanMaples/dev/jomaples/lwg3320v3.0.0

implement LWG3320

1 files changed, 716 insertions, 724 deletions

diff --git a/include/gsl/string_span b/include/gsl/string_span
index 2207291..b96c9ff 100644
--- a/include/gsl/string_span
+++ b/include/gsl/string_span
@@ -1,724 +1,716 @@
-///////////////////////////////////////////////////////////////////////////////
-//
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
-//
-// This code is licensed under the MIT License (MIT).
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#ifndef GSL_STRING_SPAN_H
-#define GSL_STRING_SPAN_H
-
-#include <gsl/gsl_assert> // for Ensures, Expects
-#include <gsl/gsl_util>   // for narrow_cast
-#include <gsl/span_ext>       // for operator!=, operator==, dynamic_extent
-
-#include <algorithm> // for equal, lexicographical_compare
-#include <array>     // for array
-#include <cstddef>   // for size_t, nullptr_t
-#include <cstdint>   // for PTRDIFF_MAX
-#include <cstring>
-#include <string>    // for basic_string, allocator, char_traits
-#include <type_traits> // for declval, is_convertible, enable_if_t, add_...
-
-#if defined(_MSC_VER) && !defined(__clang__)
-#pragma warning(push)
-
-// Turn MSVC /analyze rules that generate too much noise. TODO: fix in the tool.
-#pragma warning(disable : 26446) // TODO: bug in parser - attributes and templates
-#pragma warning(disable : 26481) // TODO: suppress does not work inside templates sometimes
-
-#if _MSC_VER < 1910
-#pragma push_macro("constexpr")
-#define constexpr /*constexpr*/
-
-#endif // _MSC_VER < 1910
-#endif // _MSC_VER
-
-namespace gsl
-{
-//
-// czstring and wzstring
-//
-// These are "tag" typedefs for C-style strings (i.e. null-terminated character arrays)
-// that allow static analysis to help find bugs.
-//
-// There are no additional features/semantics that we can find a way to add inside the
-// type system for these types that will not either incur significant runtime costs or
-// (sometimes needlessly) break existing programs when introduced.
-//
-
-template <typename CharT, std::size_t Extent = dynamic_extent>
-using basic_zstring = CharT*;
-
-template <std::size_t Extent = dynamic_extent>
-using czstring = basic_zstring<const char, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using cwzstring = basic_zstring<const wchar_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using cu16zstring = basic_zstring<const char16_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using cu32zstring = basic_zstring<const char32_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using zstring = basic_zstring<char, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using wzstring = basic_zstring<wchar_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using u16zstring = basic_zstring<char16_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using u32zstring = basic_zstring<char32_t, Extent>;
-
-namespace details
-{
-    template <class CharT>
-    std::size_t string_length(const CharT* str, std::size_t n)
-    {
-        if (str == nullptr || n == dynamic_extent) return 0;
-
-        const span<const CharT> str_span{str, n};
-
-        std::size_t len = 0;
-        while (len < n && str_span[len]) len++;
-
-        return len;
-    }
-} // namespace details
-
-//
-// ensure_sentinel()
-//
-// Provides a way to obtain an span from a contiguous sequence
-// that ends with a (non-inclusive) sentinel value.
-//
-// Will fail-fast if sentinel cannot be found before max elements are examined.
-//
-template <typename T, const T Sentinel>
-span<T, dynamic_extent> ensure_sentinel(T* seq,
-                                        std::size_t max = static_cast<std::size_t>(-1))
-{
-    Ensures(seq != nullptr);
-
-    GSL_SUPPRESS(
-        f.23) // NO-FORMAT: attribute // TODO: false positive // TODO: suppress does not work
-    auto cur = seq;
-    Ensures(cur != nullptr); // workaround for removing the warning
-
-    GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute // TODO: suppress does not work
-    while (static_cast<std::size_t>(cur - seq) < max && *cur != Sentinel) ++cur;
-    Ensures(*cur == Sentinel);
-    return {seq, static_cast<std::size_t>(cur - seq)};
-}
-
-//
-// ensure_z - creates a span for a zero terminated strings.
-// Will fail fast if a null-terminator cannot be found before
-// the limit of size_type.
-//
-template <typename CharT>
-span<CharT, dynamic_extent> ensure_z(CharT* const& sz,
-                                     std::size_t max = static_cast<std::size_t>(-1))
-{
-    return ensure_sentinel<CharT, CharT(0)>(sz, max);
-}
-
-template <typename CharT, std::size_t N>
-span<CharT, dynamic_extent> ensure_z(CharT (&sz)[N])
-{
-    return ensure_z(&sz[0], N);
-}
-
-template <class Cont>
-span<typename std::remove_pointer<typename Cont::pointer>::type, dynamic_extent>
-ensure_z(Cont& cont)
-{
-    return ensure_z(cont.data(), cont.size());
-}
-
-template <typename CharT, std::size_t>
-class basic_string_span;
-
-namespace details
-{
-    template <typename T>
-    struct is_basic_string_span_oracle : std::false_type
-    {
-    };
-
-    template <typename CharT, std::size_t Extent>
-    struct is_basic_string_span_oracle<basic_string_span<CharT, Extent>> : std::true_type
-    {
-    };
-
-    template <typename T>
-    struct is_basic_string_span : is_basic_string_span_oracle<std::remove_cv_t<T>>
-    {
-    };
-} // namespace details
-
-//
-// string_span and relatives
-//
-template <typename CharT, std::size_t Extent = dynamic_extent>
-class basic_string_span
-{
-public:
-    using element_type = CharT;
-    using value_type = std::remove_cv_t<element_type>;
-    using pointer = std::add_pointer_t<element_type>;
-    using reference = std::add_lvalue_reference_t<element_type>;
-    using const_reference = std::add_lvalue_reference_t<std::add_const_t<element_type>>;
-    using impl_type = span<element_type, Extent>;
-
-    using size_type = typename impl_type::size_type;
-    using iterator = typename impl_type::iterator;
-    using const_iterator = typename impl_type::const_iterator;
-    using reverse_iterator = typename impl_type::reverse_iterator;
-    using const_reverse_iterator = typename impl_type::const_reverse_iterator;
-
-    // default (empty)
-    constexpr basic_string_span() noexcept = default;
-
-    // copy
-    constexpr basic_string_span(const basic_string_span& other) noexcept = default;
-
-    // assign
-    constexpr basic_string_span& operator=(const basic_string_span& other) noexcept = default;
-
-    constexpr basic_string_span(pointer ptr, size_type length) : span_(ptr, length) {}
-    constexpr basic_string_span(pointer firstElem, pointer lastElem) : span_(firstElem, lastElem) {}
-
-    // From static arrays - if 0-terminated, remove 0 from the view
-    // All other containers allow 0s within the length, so we do not remove them
-    template <std::size_t N>
-    constexpr basic_string_span(element_type (&arr)[N]) : span_(remove_z(arr))
-    {}
-
-    template <std::size_t N, class ArrayElementType = std::remove_const_t<element_type>>
-    constexpr basic_string_span(std::array<ArrayElementType, N>& arr) noexcept : span_(arr)
-    {}
-
-    template <std::size_t N, class ArrayElementType = std::remove_const_t<element_type>>
-    constexpr basic_string_span(const std::array<ArrayElementType, N>& arr) noexcept : span_(arr)
-    {}
-
-    // Container signature should work for basic_string after C++17 version exists
-    template <class Traits, class Allocator>
-    // GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute // TODO: parser bug
-    constexpr basic_string_span(std::basic_string<element_type, Traits, Allocator>& str)
-        : span_(&str[0], str.length())
-    {}
-
-    template <class Traits, class Allocator>
-    constexpr basic_string_span(const std::basic_string<element_type, Traits, Allocator>& str)
-        : span_(&str[0], str.length())
-    {}
-
-    // from containers. Containers must have a pointer type and data() function signatures
-    template <class Container,
-              class = std::enable_if_t<
-                  !details::is_basic_string_span<Container>::value &&
-                  std::is_convertible<typename Container::pointer, pointer>::value &&
-                  std::is_convertible<typename Container::pointer,
-                                      decltype(std::declval<Container>().data())>::value>>
-    constexpr basic_string_span(Container& cont) : span_(cont)
-    {}
-
-    template <class Container,
-              class = std::enable_if_t<
-                  !details::is_basic_string_span<Container>::value &&
-                  std::is_convertible<typename Container::pointer, pointer>::value &&
-                  std::is_convertible<typename Container::pointer,
-                                      decltype(std::declval<Container>().data())>::value>>
-    constexpr basic_string_span(const Container& cont) : span_(cont)
-    {}
-
-    // from string_span
-    template <
-        class OtherValueType, std::size_t OtherExtent,
-        class = std::enable_if_t<std::is_convertible<
-            typename basic_string_span<OtherValueType, OtherExtent>::impl_type, impl_type>::value>>
-    constexpr basic_string_span(basic_string_span<OtherValueType, OtherExtent> other)
-        : span_(other.data(), other.length())
-    {}
-
-    template <size_type Count>
-    constexpr basic_string_span<element_type, Count> first() const
-    {
-        return {span_.template first<Count>()};
-    }
-
-    constexpr basic_string_span<element_type, dynamic_extent> first(size_type count) const
-    {
-        return {span_.first(count)};
-    }
-
-    template <size_type Count>
-    constexpr basic_string_span<element_type, Count> last() const
-    {
-        return {span_.template last<Count>()};
-    }
-
-    constexpr basic_string_span<element_type, dynamic_extent> last(size_type count) const
-    {
-        return {span_.last(count)};
-    }
-
-    template <size_type Offset, size_type Count>
-    constexpr basic_string_span<element_type, Count> subspan() const
-    {
-        return {span_.template subspan<Offset, Count>()};
-    }
-
-    constexpr basic_string_span<element_type, dynamic_extent>
-    subspan(size_type offset, size_type count = dynamic_extent) const
-    {
-        return {span_.subspan(offset, count)};
-    }
-
-    constexpr reference operator[](size_type idx) const { return span_[idx]; }
-    constexpr reference operator()(size_type idx) const { return span_[idx]; }
-
-    constexpr pointer data() const { return span_.data(); }
-
-    constexpr size_type length() const noexcept { return span_.size(); }
-    constexpr size_type size() const noexcept { return span_.size(); }
-    constexpr size_type size_bytes() const noexcept { return span_.size_bytes(); }
-    constexpr size_type length_bytes() const noexcept { return span_.length_bytes(); }
-    constexpr bool empty() const noexcept { return size() == 0; }
-
-    constexpr iterator begin() const noexcept { return span_.begin(); }
-    constexpr iterator end() const noexcept { return span_.end(); }
-
-    constexpr const_iterator cbegin() const noexcept { return span_.cbegin(); }
-    constexpr const_iterator cend() const noexcept { return span_.cend(); }
-
-    constexpr reverse_iterator rbegin() const noexcept { return span_.rbegin(); }
-    constexpr reverse_iterator rend() const noexcept { return span_.rend(); }
-
-    constexpr const_reverse_iterator crbegin() const noexcept { return span_.crbegin(); }
-    constexpr const_reverse_iterator crend() const noexcept { return span_.crend(); }
-
-private:
-    static impl_type remove_z(pointer const& sz, std::size_t max)
-    {
-        return {sz, details::string_length(sz, max)};
-    }
-
-    template <std::size_t N>
-    static impl_type remove_z(element_type (&sz)[N])
-    {
-        return remove_z(&sz[0], N);
-    }
-
-    impl_type span_;
-};
-
-template <std::size_t Extent = dynamic_extent>
-using string_span = basic_string_span<char, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using cstring_span = basic_string_span<const char, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using wstring_span = basic_string_span<wchar_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using cwstring_span = basic_string_span<const wchar_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using u16string_span = basic_string_span<char16_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using cu16string_span = basic_string_span<const char16_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using u32string_span = basic_string_span<char32_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using cu32string_span = basic_string_span<const char32_t, Extent>;
-
-//
-// to_string() allow (explicit) conversions from string_span to string
-//
-
-template <typename CharT, std::size_t Extent>
-std::basic_string<typename std::remove_const<CharT>::type>
-to_string(basic_string_span<CharT, Extent> view)
-{
-    return {view.data(), narrow_cast<std::size_t>(view.length())};
-}
-
-template <typename CharT, typename Traits = typename std::char_traits<CharT>,
-          typename Allocator = std::allocator<CharT>, typename gCharT, std::size_t Extent>
-std::basic_string<CharT, Traits, Allocator> to_basic_string(basic_string_span<gCharT, Extent> view)
-{
-    return {view.data(), narrow_cast<std::size_t>(view.length())};
-}
-
-template <class ElementType, std::size_t Extent>
-basic_string_span<const byte, details::calculate_byte_size<ElementType, Extent>::value>
-as_bytes(basic_string_span<ElementType, Extent> s) noexcept
-{
-    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
-    return {reinterpret_cast<const byte*>(s.data()), s.size_bytes()};
-}
-
-template <class ElementType, std::size_t Extent,
-          class = std::enable_if_t<!std::is_const<ElementType>::value>>
-basic_string_span<byte, details::calculate_byte_size<ElementType, Extent>::value>
-as_writable_bytes(basic_string_span<ElementType, Extent> s) noexcept
-{
-    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
-    return {reinterpret_cast<byte*>(s.data()), s.size_bytes()};
-}
-
-// zero-terminated string span, used to convert
-// zero-terminated spans to legacy strings
-template <typename CharT, std::size_t Extent = dynamic_extent>
-class basic_zstring_span
-{
-public:
-    using value_type = CharT;
-    using const_value_type = std::add_const_t<CharT>;
-
-    using pointer = std::add_pointer_t<value_type>;
-    using const_pointer = std::add_pointer_t<const_value_type>;
-
-    using zstring_type = basic_zstring<value_type, Extent>;
-    using const_zstring_type = basic_zstring<const_value_type, Extent>;
-
-    using impl_type = span<value_type, Extent>;
-    using string_span_type = basic_string_span<value_type, Extent>;
-
-    constexpr basic_zstring_span(impl_type s) : span_(s)
-    {
-        // expects a zero-terminated span
-        Expects(s[s.size() - 1] == '\0');
-    }
-
-    // copy
-    constexpr basic_zstring_span(const basic_zstring_span& other) = default;
-
-    // move
-    constexpr basic_zstring_span(basic_zstring_span&& other) = default;
-
-    // assign
-    constexpr basic_zstring_span& operator=(const basic_zstring_span& other) = default;
-
-    // move assign
-    constexpr basic_zstring_span& operator=(basic_zstring_span&& other) = default;
-
-    constexpr bool empty() const noexcept { return span_.size() == 0; }
-
-    constexpr string_span_type as_string_span() const noexcept
-    {
-        const auto sz = span_.size();
-        return {span_.data(), sz > 1 ? sz - 1 : 0};
-    }
-    constexpr string_span_type ensure_z() const { return gsl::ensure_z(span_); }
-
-    constexpr const_zstring_type assume_z() const noexcept { return span_.data(); }
-
-private:
-    impl_type span_;
-};
-
-template <std::size_t Max = dynamic_extent>
-using zstring_span = basic_zstring_span<char, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using wzstring_span = basic_zstring_span<wchar_t, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using u16zstring_span = basic_zstring_span<char16_t, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using u32zstring_span = basic_zstring_span<char32_t, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using czstring_span = basic_zstring_span<const char, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using cwzstring_span = basic_zstring_span<const wchar_t, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using cu16zstring_span = basic_zstring_span<const char16_t, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using cu32zstring_span = basic_zstring_span<const char32_t, Max>;
-
-// operator ==
-template <class CharT, std::size_t Extent, class T,
-          class = std::enable_if_t<
-              details::is_basic_string_span<T>::value ||
-              std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>>>::value>>
-bool operator==(const gsl::basic_string_span<CharT, Extent>& one, const T& other)
-{
-    const gsl::basic_string_span<std::add_const_t<CharT>> tmp(other);
-    return std::equal(one.begin(), one.end(), tmp.begin(), tmp.end());
-}
-
-template <class CharT, std::size_t Extent, class T,
-          class = std::enable_if_t<
-              !details::is_basic_string_span<T>::value &&
-              std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>>>::value>>
-bool operator==(const T& one, const gsl::basic_string_span<CharT, Extent>& other)
-{
-    const gsl::basic_string_span<std::add_const_t<CharT>> tmp(one);
-    return std::equal(tmp.begin(), tmp.end(), other.begin(), other.end());
-}
-
-// operator !=
-template <typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-          typename = std::enable_if_t<std::is_convertible<
-              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
-bool operator!=(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return !(one == other);
-}
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename = std::enable_if_t<
-        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
-        !gsl::details::is_basic_string_span<T>::value>>
-bool operator!=(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return !(one == other);
-}
-
-// operator<
-template <typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-          typename = std::enable_if_t<std::is_convertible<
-              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
-bool operator<(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    const gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);
-    return std::lexicographical_compare(one.begin(), one.end(), tmp.begin(), tmp.end());
-}
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename = std::enable_if_t<
-        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
-        !gsl::details::is_basic_string_span<T>::value>>
-bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(one);
-    return std::lexicographical_compare(tmp.begin(), tmp.end(), other.begin(), other.end());
-}
-
-#ifndef _MSC_VER
-
-// VS treats temp and const containers as convertible to basic_string_span,
-// so the cases below are already covered by the previous operators
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator<(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);
-    return std::lexicographical_compare(one.begin(), one.end(), tmp.begin(), tmp.end());
-}
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(one);
-    return std::lexicographical_compare(tmp.begin(), tmp.end(), other.begin(), other.end());
-}
-#endif
-
-// operator <=
-template <typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-          typename = std::enable_if_t<std::is_convertible<
-              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
-bool operator<=(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return !(other < one);
-}
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename = std::enable_if_t<
-        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
-        !gsl::details::is_basic_string_span<T>::value>>
-bool operator<=(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return !(other < one);
-}
-
-#ifndef _MSC_VER
-
-// VS treats temp and const containers as convertible to basic_string_span,
-// so the cases below are already covered by the previous operators
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator<=(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return !(other < one);
-}
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator<=(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return !(other < one);
-}
-#endif
-
-// operator>
-template <typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-          typename = std::enable_if_t<std::is_convertible<
-              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
-bool operator>(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return other < one;
-}
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename = std::enable_if_t<
-        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
-        !gsl::details::is_basic_string_span<T>::value>>
-bool operator>(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return other < one;
-}
-
-#ifndef _MSC_VER
-
-// VS treats temp and const containers as convertible to basic_string_span,
-// so the cases below are already covered by the previous operators
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator>(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return other < one;
-}
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator>(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return other < one;
-}
-#endif
-
-// operator >=
-template <typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-          typename = std::enable_if_t<std::is_convertible<
-              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
-bool operator>=(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return !(one < other);
-}
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename = std::enable_if_t<
-        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
-        !gsl::details::is_basic_string_span<T>::value>>
-bool operator>=(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return !(one < other);
-}
-
-#ifndef _MSC_VER
-
-// VS treats temp and const containers as convertible to basic_string_span,
-// so the cases below are already covered by the previous operators
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator>=(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return !(one < other);
-}
-
-template <
-    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator>=(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return !(one < other);
-}
-#endif
-} // namespace gsl
-
-#if defined(_MSC_VER) && !defined(__clang__)
-#pragma warning(pop)
-
-#if _MSC_VER < 1910
-#undef constexpr
-#pragma pop_macro("constexpr")
-
-#endif // _MSC_VER < 1910
-#endif // _MSC_VER
-
-#endif // GSL_STRING_SPAN_H
+///////////////////////////////////////////////////////////////////////////////

+//

+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.

+//

+// This code is licensed under the MIT License (MIT).

+//

+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

+// THE SOFTWARE.

+//

+///////////////////////////////////////////////////////////////////////////////

+

+#ifndef GSL_STRING_SPAN_H

+#define GSL_STRING_SPAN_H

+

+#include <gsl/gsl_assert> // for Ensures, Expects

+#include <gsl/gsl_util>   // for narrow_cast

+#include <gsl/span_ext>       // for operator!=, operator==, dynamic_extent

+

+#include <algorithm> // for equal, lexicographical_compare

+#include <array>     // for array

+#include <cstddef>   // for size_t, nullptr_t

+#include <cstdint>   // for PTRDIFF_MAX

+#include <cstring>

+#include <string>    // for basic_string, allocator, char_traits

+#include <type_traits> // for declval, is_convertible, enable_if_t, add_...

+

+#if defined(_MSC_VER) && !defined(__clang__)

+#pragma warning(push)

+

+// Turn MSVC /analyze rules that generate too much noise. TODO: fix in the tool.

+#pragma warning(disable : 26446) // TODO: bug in parser - attributes and templates

+#pragma warning(disable : 26481) // TODO: suppress does not work inside templates sometimes

+

+#if _MSC_VER < 1910

+#pragma push_macro("constexpr")

+#define constexpr /*constexpr*/

+

+#endif // _MSC_VER < 1910

+#endif // _MSC_VER

+

+namespace gsl

+{

+//

+// czstring and wzstring

+//

+// These are "tag" typedefs for C-style strings (i.e. null-terminated character arrays)

+// that allow static analysis to help find bugs.

+//

+// There are no additional features/semantics that we can find a way to add inside the

+// type system for these types that will not either incur significant runtime costs or

+// (sometimes needlessly) break existing programs when introduced.

+//

+

+template <typename CharT, std::size_t Extent = dynamic_extent>

+using basic_zstring = CharT*;

+

+template <std::size_t Extent = dynamic_extent>

+using czstring = basic_zstring<const char, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using cwzstring = basic_zstring<const wchar_t, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using cu16zstring = basic_zstring<const char16_t, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using cu32zstring = basic_zstring<const char32_t, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using zstring = basic_zstring<char, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using wzstring = basic_zstring<wchar_t, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using u16zstring = basic_zstring<char16_t, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using u32zstring = basic_zstring<char32_t, Extent>;

+

+namespace details

+{

+    template <class CharT>

+    std::size_t string_length(const CharT* str, std::size_t n)

+    {

+        if (str == nullptr || n == dynamic_extent) return 0;

+

+        const span<const CharT> str_span{str, n};

+

+        std::size_t len = 0;

+        while (len < n && str_span[len]) len++;

+

+        return len;

+    }

+} // namespace details

+

+//

+// ensure_sentinel()

+//

+// Provides a way to obtain an span from a contiguous sequence

+// that ends with a (non-inclusive) sentinel value.

+//

+// Will fail-fast if sentinel cannot be found before max elements are examined.

+//

+template <typename T, const T Sentinel>

+span<T, dynamic_extent> ensure_sentinel(T* seq,

+                                        std::size_t max = static_cast<std::size_t>(-1))

+{

+    Ensures(seq != nullptr);

+

+    GSL_SUPPRESS(

+        f.23) // NO-FORMAT: attribute // TODO: false positive // TODO: suppress does not work

+    auto cur = seq;

+    Ensures(cur != nullptr); // workaround for removing the warning

+

+    GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute // TODO: suppress does not work

+    while (static_cast<std::size_t>(cur - seq) < max && *cur != Sentinel) ++cur;

+    Ensures(*cur == Sentinel);

+    return {seq, static_cast<std::size_t>(cur - seq)};

+}

+

+//

+// ensure_z - creates a span for a zero terminated strings.

+// Will fail fast if a null-terminator cannot be found before

+// the limit of size_type.

+//

+template <typename CharT>

+span<CharT, dynamic_extent> ensure_z(CharT* const& sz,

+                                     std::size_t max = static_cast<std::size_t>(-1))

+{

+    return ensure_sentinel<CharT, CharT(0)>(sz, max);

+}

+

+template <typename CharT, std::size_t N>

+span<CharT, dynamic_extent> ensure_z(CharT (&sz)[N])

+{

+    return ensure_z(&sz[0], N);

+}

+

+template <class Cont>

+span<typename std::remove_pointer<typename Cont::pointer>::type, dynamic_extent>

+ensure_z(Cont& cont)

+{

+    return ensure_z(cont.data(), cont.size());

+}

+

+template <typename CharT, std::size_t>

+class basic_string_span;

+

+namespace details

+{

+    template <typename T>

+    struct is_basic_string_span_oracle : std::false_type

+    {

+    };

+

+    template <typename CharT, std::size_t Extent>

+    struct is_basic_string_span_oracle<basic_string_span<CharT, Extent>> : std::true_type

+    {

+    };

+

+    template <typename T>

+    struct is_basic_string_span : is_basic_string_span_oracle<std::remove_cv_t<T>>

+    {

+    };

+} // namespace details

+

+//

+// string_span and relatives

+//

+template <typename CharT, std::size_t Extent = dynamic_extent>

+class basic_string_span

+{

+public:

+    using element_type = CharT;

+    using value_type = std::remove_cv_t<element_type>;

+    using pointer = std::add_pointer_t<element_type>;

+    using reference = std::add_lvalue_reference_t<element_type>;

+    using const_reference = std::add_lvalue_reference_t<std::add_const_t<element_type>>;

+    using impl_type = span<element_type, Extent>;

+

+    using size_type = typename impl_type::size_type;

+    using iterator = typename impl_type::iterator;

+    using reverse_iterator = typename impl_type::reverse_iterator;

+

+    // default (empty)

+    constexpr basic_string_span() noexcept = default;

+

+    // copy

+    constexpr basic_string_span(const basic_string_span& other) noexcept = default;

+

+    // assign

+    constexpr basic_string_span& operator=(const basic_string_span& other) noexcept = default;

+

+    constexpr basic_string_span(pointer ptr, size_type length) : span_(ptr, length) {}

+    constexpr basic_string_span(pointer firstElem, pointer lastElem) : span_(firstElem, lastElem) {}

+

+    // From static arrays - if 0-terminated, remove 0 from the view

+    // All other containers allow 0s within the length, so we do not remove them

+    template <std::size_t N>

+    constexpr basic_string_span(element_type (&arr)[N]) : span_(remove_z(arr))

+    {}

+

+    template <std::size_t N, class ArrayElementType = std::remove_const_t<element_type>>

+    constexpr basic_string_span(std::array<ArrayElementType, N>& arr) noexcept : span_(arr)

+    {}

+

+    template <std::size_t N, class ArrayElementType = std::remove_const_t<element_type>>

+    constexpr basic_string_span(const std::array<ArrayElementType, N>& arr) noexcept : span_(arr)

+    {}

+

+    // Container signature should work for basic_string after C++17 version exists

+    template <class Traits, class Allocator>

+    // GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute // TODO: parser bug

+    constexpr basic_string_span(std::basic_string<element_type, Traits, Allocator>& str)

+        : span_(&str[0], str.length())

+    {}

+

+    template <class Traits, class Allocator>

+    constexpr basic_string_span(const std::basic_string<element_type, Traits, Allocator>& str)

+        : span_(&str[0], str.length())

+    {}

+

+    // from containers. Containers must have a pointer type and data() function signatures

+    template <class Container,

+              class = std::enable_if_t<

+                  !details::is_basic_string_span<Container>::value &&

+                  std::is_convertible<typename Container::pointer, pointer>::value &&

+                  std::is_convertible<typename Container::pointer,

+                                      decltype(std::declval<Container>().data())>::value>>

+    constexpr basic_string_span(Container& cont) : span_(cont)

+    {}

+

+    template <class Container,

+              class = std::enable_if_t<

+                  !details::is_basic_string_span<Container>::value &&

+                  std::is_convertible<typename Container::pointer, pointer>::value &&

+                  std::is_convertible<typename Container::pointer,

+                                      decltype(std::declval<Container>().data())>::value>>

+    constexpr basic_string_span(const Container& cont) : span_(cont)

+    {}

+

+    // from string_span

+    template <

+        class OtherValueType, std::size_t OtherExtent,

+        class = std::enable_if_t<std::is_convertible<

+            typename basic_string_span<OtherValueType, OtherExtent>::impl_type, impl_type>::value>>

+    constexpr basic_string_span(basic_string_span<OtherValueType, OtherExtent> other)

+        : span_(other.data(), other.length())

+    {}

+

+    template <size_type Count>

+    constexpr basic_string_span<element_type, Count> first() const

+    {

+        return {span_.template first<Count>()};

+    }

+

+    constexpr basic_string_span<element_type, dynamic_extent> first(size_type count) const

+    {

+        return {span_.first(count)};

+    }

+

+    template <size_type Count>

+    constexpr basic_string_span<element_type, Count> last() const

+    {

+        return {span_.template last<Count>()};

+    }

+

+    constexpr basic_string_span<element_type, dynamic_extent> last(size_type count) const

+    {

+        return {span_.last(count)};

+    }

+

+    template <size_type Offset, size_type Count>

+    constexpr basic_string_span<element_type, Count> subspan() const

+    {

+        return {span_.template subspan<Offset, Count>()};

+    }

+

+    constexpr basic_string_span<element_type, dynamic_extent>

+    subspan(size_type offset, size_type count = dynamic_extent) const

+    {

+        return {span_.subspan(offset, count)};

+    }

+

+    constexpr reference operator[](size_type idx) const { return span_[idx]; }

+    constexpr reference operator()(size_type idx) const { return span_[idx]; }

+

+    constexpr pointer data() const { return span_.data(); }

+

+    constexpr size_type length() const noexcept { return span_.size(); }

+    constexpr size_type size() const noexcept { return span_.size(); }

+    constexpr size_type size_bytes() const noexcept { return span_.size_bytes(); }

+    constexpr size_type length_bytes() const noexcept { return span_.length_bytes(); }

+    constexpr bool empty() const noexcept { return size() == 0; }

+

+    constexpr iterator begin() const noexcept { return span_.begin(); }

+    constexpr iterator end() const noexcept { return span_.end(); }

+

+    constexpr reverse_iterator rbegin() const noexcept { return span_.rbegin(); }

+    constexpr reverse_iterator rend() const noexcept { return span_.rend(); }

+

+private:

+    static impl_type remove_z(pointer const& sz, std::size_t max)

+    {

+        return {sz, details::string_length(sz, max)};

+    }

+

+    template <std::size_t N>

+    static impl_type remove_z(element_type (&sz)[N])

+    {

+        return remove_z(&sz[0], N);

+    }

+

+    impl_type span_;

+};

+

+template <std::size_t Extent = dynamic_extent>

+using string_span = basic_string_span<char, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using cstring_span = basic_string_span<const char, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using wstring_span = basic_string_span<wchar_t, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using cwstring_span = basic_string_span<const wchar_t, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using u16string_span = basic_string_span<char16_t, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using cu16string_span = basic_string_span<const char16_t, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using u32string_span = basic_string_span<char32_t, Extent>;

+

+template <std::size_t Extent = dynamic_extent>

+using cu32string_span = basic_string_span<const char32_t, Extent>;

+

+//

+// to_string() allow (explicit) conversions from string_span to string

+//

+

+template <typename CharT, std::size_t Extent>

+std::basic_string<typename std::remove_const<CharT>::type>

+to_string(basic_string_span<CharT, Extent> view)

+{

+    return {view.data(), narrow_cast<std::size_t>(view.length())};

+}

+

+template <typename CharT, typename Traits = typename std::char_traits<CharT>,

+          typename Allocator = std::allocator<CharT>, typename gCharT, std::size_t Extent>

+std::basic_string<CharT, Traits, Allocator> to_basic_string(basic_string_span<gCharT, Extent> view)

+{

+    return {view.data(), narrow_cast<std::size_t>(view.length())};

+}

+

+template <class ElementType, std::size_t Extent>

+basic_string_span<const byte, details::calculate_byte_size<ElementType, Extent>::value>

+as_bytes(basic_string_span<ElementType, Extent> s) noexcept

+{

+    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute

+    return {reinterpret_cast<const byte*>(s.data()), s.size_bytes()};

+}

+

+template <class ElementType, std::size_t Extent,

+          class = std::enable_if_t<!std::is_const<ElementType>::value>>

+basic_string_span<byte, details::calculate_byte_size<ElementType, Extent>::value>

+as_writable_bytes(basic_string_span<ElementType, Extent> s) noexcept

+{

+    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute

+    return {reinterpret_cast<byte*>(s.data()), s.size_bytes()};

+}

+

+// zero-terminated string span, used to convert

+// zero-terminated spans to legacy strings

+template <typename CharT, std::size_t Extent = dynamic_extent>

+class basic_zstring_span

+{

+public:

+    using value_type = CharT;

+    using const_value_type = std::add_const_t<CharT>;

+

+    using pointer = std::add_pointer_t<value_type>;

+    using const_pointer = std::add_pointer_t<const_value_type>;

+

+    using zstring_type = basic_zstring<value_type, Extent>;

+    using const_zstring_type = basic_zstring<const_value_type, Extent>;

+

+    using impl_type = span<value_type, Extent>;

+    using string_span_type = basic_string_span<value_type, Extent>;

+

+    constexpr basic_zstring_span(impl_type s) : span_(s)

+    {

+        // expects a zero-terminated span

+        Expects(s[s.size() - 1] == '\0');

+    }

+

+    // copy

+    constexpr basic_zstring_span(const basic_zstring_span& other) = default;

+

+    // move

+    constexpr basic_zstring_span(basic_zstring_span&& other) = default;

+

+    // assign

+    constexpr basic_zstring_span& operator=(const basic_zstring_span& other) = default;

+

+    // move assign

+    constexpr basic_zstring_span& operator=(basic_zstring_span&& other) = default;

+

+    constexpr bool empty() const noexcept { return span_.size() == 0; }

+

+    constexpr string_span_type as_string_span() const noexcept

+    {

+        const auto sz = span_.size();

+        return {span_.data(), sz > 1 ? sz - 1 : 0};

+    }

+    constexpr string_span_type ensure_z() const { return gsl::ensure_z(span_); }

+

+    constexpr const_zstring_type assume_z() const noexcept { return span_.data(); }

+

+private:

+    impl_type span_;

+};

+

+template <std::size_t Max = dynamic_extent>

+using zstring_span = basic_zstring_span<char, Max>;

+

+template <std::size_t Max = dynamic_extent>

+using wzstring_span = basic_zstring_span<wchar_t, Max>;

+

+template <std::size_t Max = dynamic_extent>

+using u16zstring_span = basic_zstring_span<char16_t, Max>;

+

+template <std::size_t Max = dynamic_extent>

+using u32zstring_span = basic_zstring_span<char32_t, Max>;

+

+template <std::size_t Max = dynamic_extent>

+using czstring_span = basic_zstring_span<const char, Max>;

+

+template <std::size_t Max = dynamic_extent>

+using cwzstring_span = basic_zstring_span<const wchar_t, Max>;

+

+template <std::size_t Max = dynamic_extent>

+using cu16zstring_span = basic_zstring_span<const char16_t, Max>;

+

+template <std::size_t Max = dynamic_extent>

+using cu32zstring_span = basic_zstring_span<const char32_t, Max>;

+

+// operator ==

+template <class CharT, std::size_t Extent, class T,

+          class = std::enable_if_t<

+              details::is_basic_string_span<T>::value ||

+              std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>>>::value>>

+bool operator==(const gsl::basic_string_span<CharT, Extent>& one, const T& other)

+{

+    const gsl::basic_string_span<std::add_const_t<CharT>> tmp(other);

+    return std::equal(one.begin(), one.end(), tmp.begin(), tmp.end());

+}

+

+template <class CharT, std::size_t Extent, class T,

+          class = std::enable_if_t<

+              !details::is_basic_string_span<T>::value &&

+              std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>>>::value>>

+bool operator==(const T& one, const gsl::basic_string_span<CharT, Extent>& other)

+{

+    const gsl::basic_string_span<std::add_const_t<CharT>> tmp(one);

+    return std::equal(tmp.begin(), tmp.end(), other.begin(), other.end());

+}

+

+// operator !=

+template <typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+          typename = std::enable_if_t<std::is_convertible<

+              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>

+bool operator!=(gsl::basic_string_span<CharT, Extent> one, const T& other)

+{

+    return !(one == other);

+}

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename = std::enable_if_t<

+        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&

+        !gsl::details::is_basic_string_span<T>::value>>

+bool operator!=(const T& one, gsl::basic_string_span<CharT, Extent> other)

+{

+    return !(one == other);

+}

+

+// operator<

+template <typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+          typename = std::enable_if_t<std::is_convertible<

+              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>

+bool operator<(gsl::basic_string_span<CharT, Extent> one, const T& other)

+{

+    const gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);

+    return std::lexicographical_compare(one.begin(), one.end(), tmp.begin(), tmp.end());

+}

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename = std::enable_if_t<

+        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&

+        !gsl::details::is_basic_string_span<T>::value>>

+bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other)

+{

+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(one);

+    return std::lexicographical_compare(tmp.begin(), tmp.end(), other.begin(), other.end());

+}

+

+#ifndef _MSC_VER

+

+// VS treats temp and const containers as convertible to basic_string_span,

+// so the cases below are already covered by the previous operators

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename DataType = typename T::value_type,

+    typename = std::enable_if_t<

+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&

+        std::is_convertible<DataType*, CharT*>::value &&

+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,

+                     DataType>::value>>

+bool operator<(gsl::basic_string_span<CharT, Extent> one, const T& other)

+{

+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);

+    return std::lexicographical_compare(one.begin(), one.end(), tmp.begin(), tmp.end());

+}

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename DataType = typename T::value_type,

+    typename = std::enable_if_t<

+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&

+        std::is_convertible<DataType*, CharT*>::value &&

+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,

+                     DataType>::value>>

+bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other)

+{

+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(one);

+    return std::lexicographical_compare(tmp.begin(), tmp.end(), other.begin(), other.end());

+}

+#endif

+

+// operator <=

+template <typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+          typename = std::enable_if_t<std::is_convertible<

+              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>

+bool operator<=(gsl::basic_string_span<CharT, Extent> one, const T& other)

+{

+    return !(other < one);

+}

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename = std::enable_if_t<

+        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&

+        !gsl::details::is_basic_string_span<T>::value>>

+bool operator<=(const T& one, gsl::basic_string_span<CharT, Extent> other)

+{

+    return !(other < one);

+}

+

+#ifndef _MSC_VER

+

+// VS treats temp and const containers as convertible to basic_string_span,

+// so the cases below are already covered by the previous operators

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename DataType = typename T::value_type,

+    typename = std::enable_if_t<

+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&

+        std::is_convertible<DataType*, CharT*>::value &&

+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,

+                     DataType>::value>>

+bool operator<=(gsl::basic_string_span<CharT, Extent> one, const T& other)

+{

+    return !(other < one);

+}

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename DataType = typename T::value_type,

+    typename = std::enable_if_t<

+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&

+        std::is_convertible<DataType*, CharT*>::value &&

+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,

+                     DataType>::value>>

+bool operator<=(const T& one, gsl::basic_string_span<CharT, Extent> other)

+{

+    return !(other < one);

+}

+#endif

+

+// operator>

+template <typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+          typename = std::enable_if_t<std::is_convertible<

+              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>

+bool operator>(gsl::basic_string_span<CharT, Extent> one, const T& other)

+{

+    return other < one;

+}

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename = std::enable_if_t<

+        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&

+        !gsl::details::is_basic_string_span<T>::value>>

+bool operator>(const T& one, gsl::basic_string_span<CharT, Extent> other)

+{

+    return other < one;

+}

+

+#ifndef _MSC_VER

+

+// VS treats temp and const containers as convertible to basic_string_span,

+// so the cases below are already covered by the previous operators

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename DataType = typename T::value_type,

+    typename = std::enable_if_t<

+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&

+        std::is_convertible<DataType*, CharT*>::value &&

+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,

+                     DataType>::value>>

+bool operator>(gsl::basic_string_span<CharT, Extent> one, const T& other)

+{

+    return other < one;

+}

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename DataType = typename T::value_type,

+    typename = std::enable_if_t<

+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&

+        std::is_convertible<DataType*, CharT*>::value &&

+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,

+                     DataType>::value>>

+bool operator>(const T& one, gsl::basic_string_span<CharT, Extent> other)

+{

+    return other < one;

+}

+#endif

+

+// operator >=

+template <typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+          typename = std::enable_if_t<std::is_convertible<

+              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>

+bool operator>=(gsl::basic_string_span<CharT, Extent> one, const T& other)

+{

+    return !(one < other);

+}

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename = std::enable_if_t<

+        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&

+        !gsl::details::is_basic_string_span<T>::value>>

+bool operator>=(const T& one, gsl::basic_string_span<CharT, Extent> other)

+{

+    return !(one < other);

+}

+

+#ifndef _MSC_VER

+

+// VS treats temp and const containers as convertible to basic_string_span,

+// so the cases below are already covered by the previous operators

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename DataType = typename T::value_type,

+    typename = std::enable_if_t<

+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&

+        std::is_convertible<DataType*, CharT*>::value &&

+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,

+                     DataType>::value>>

+bool operator>=(gsl::basic_string_span<CharT, Extent> one, const T& other)

+{

+    return !(one < other);

+}

+

+template <

+    typename CharT, std::size_t Extent = gsl::dynamic_extent, typename T,

+    typename DataType = typename T::value_type,

+    typename = std::enable_if_t<

+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&

+        std::is_convertible<DataType*, CharT*>::value &&

+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,

+                     DataType>::value>>

+bool operator>=(const T& one, gsl::basic_string_span<CharT, Extent> other)

+{

+    return !(one < other);

+}

+#endif

+} // namespace gsl

+

+#if defined(_MSC_VER) && !defined(__clang__)

+#pragma warning(pop)

+

+#if _MSC_VER < 1910

+#undef constexpr

+#pragma pop_macro("constexpr")

+

+#endif // _MSC_VER < 1910

+#endif // _MSC_VER

+

+#endif // GSL_STRING_SPAN_H