text: /*
     Copyright (c) Marshall Clow 2012-2015.
     Copyright (c) Beman Dawes 2015
     Copyright (c) Glen Joseph Fernandes 2019 (glenjofe@gmail.com)
  
     Distributed under the Boost Software License, Version 1.0. (See accompanying
     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  
      For more information, see http://www.boost.org
  
      Based on the StringRef implementation in LLVM (http://llvm.org) and
      N3422 by Jeffrey Yasskin
          http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3442.html
      Updated July 2015 to reflect the Library Fundamentals TS
          http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4480.html
  */
  
  #ifndef BOOST_STRING_VIEW_HPP
  #define BOOST_STRING_VIEW_HPP
  
  #include <boost/config.hpp>
  #include <boost/detail/workaround.hpp>
  #include <boost/io/ostream_put.hpp>
  #include <boost/utility/string_view_fwd.hpp>
  #include <boost/throw_exception.hpp>
  
  #include <cstddef>
  #include <stdexcept>
  #include <algorithm>
  #include <iterator>
  #include <string>
  #include <cstring>
  #include <iosfwd>
  
  #if defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS) || (defined(BOOST_GCC) && ((BOOST_GCC+0) / 100) <= 406)
  // GCC 4.6 cannot handle a defaulted function with noexcept specifier
  #define BOOST_STRING_VIEW_NO_CXX11_DEFAULTED_NOEXCEPT_FUNCTIONS
  #endif
  
  namespace boost {
  
      namespace detail {
      //  A helper functor because sometimes we don't have lambdas
          template <typename charT, typename traits>
          class string_view_traits_eq {
          public:
              string_view_traits_eq ( charT ch ) : ch_(ch) {}
              bool operator()( charT val ) const { return traits::eq (ch_, val); }
              charT ch_;
              };
          }
  
      template<typename charT, typename traits>  // traits defaulted in string_view_fwd.hpp
      class basic_string_view {
      public:
        // types
        typedef traits                                traits_type;
        typedef charT                                 value_type;
        typedef charT*                                pointer;
        typedef const charT*                          const_pointer;
        typedef charT&                                reference;
        typedef const charT&                          const_reference;
        typedef const_pointer                         const_iterator; // impl-defined
        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;
        static BOOST_CONSTEXPR_OR_CONST size_type     npos = size_type(-1);
  
        // construct/copy
        BOOST_CONSTEXPR basic_string_view() BOOST_NOEXCEPT
          : ptr_(NULL), len_(0) {}
  
        // by defaulting these functions, basic_string_ref becomes
        //  trivially copy/move constructible.
        BOOST_CONSTEXPR basic_string_view(const basic_string_view &rhs) BOOST_NOEXCEPT
  #ifndef BOOST_STRING_VIEW_NO_CXX11_DEFAULTED_NOEXCEPT_FUNCTIONS
          = default;
  #else
          : ptr_(rhs.ptr_), len_(rhs.len_) {}
  #endif
  
        basic_string_view& operator=(const basic_string_view &rhs) BOOST_NOEXCEPT
  #ifndef BOOST_STRING_VIEW_NO_CXX11_DEFAULTED_NOEXCEPT_FUNCTIONS
              = default;
  #else
          {
          ptr_ = rhs.ptr_;
          len_ = rhs.len_;
          return *this;
          }
  #endif
  
        template<typename Allocator>
          basic_string_view(const std::basic_string<charT, traits, Allocator>& str) BOOST_NOEXCEPT
            : ptr_(str.data()), len_(str.length()) {}
  
  // #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && !defined(BOOST_NO_CXX11_DELETED_FUNCTIONS)
  //       // Constructing a string_view from a temporary string is a bad idea
  //       template<typename Allocator>
  //         basic_string_view(      std::basic_string<charT, traits, Allocator>&&)
  //           = delete;
  // #endif
  
        BOOST_CONSTEXPR basic_string_view(const charT* str)
          : ptr_(str), len_(traits::length(str)) {}
  
        BOOST_CONSTEXPR basic_string_view(const charT* str, size_type len)
          : ptr_(str), len_(len) {}
  
          // iterators
          BOOST_CONSTEXPR const_iterator   begin() const BOOST_NOEXCEPT { return ptr_; }
          BOOST_CONSTEXPR const_iterator  cbegin() const BOOST_NOEXCEPT { return ptr_; }
          BOOST_CONSTEXPR const_iterator     end() const BOOST_NOEXCEPT { return ptr_ + len_; }
          BOOST_CONSTEXPR const_iterator    cend() const BOOST_NOEXCEPT { return ptr_ + len_; }
                  const_reverse_iterator  rbegin() const BOOST_NOEXCEPT { return const_reverse_iterator(end()); }
                  const_reverse_iterator crbegin() const BOOST_NOEXCEPT { return const_reverse_iterator(end()); }
                  const_reverse_iterator    rend() const BOOST_NOEXCEPT { return const_reverse_iterator(begin()); }
                  const_reverse_iterator   crend() const BOOST_NOEXCEPT { return const_reverse_iterator(begin()); }
  
          // capacity
          BOOST_CONSTEXPR size_type size()     const BOOST_NOEXCEPT { return len_; }
          BOOST_CONSTEXPR size_type length()   const BOOST_NOEXCEPT { return len_; }
          BOOST_CONSTEXPR size_type max_size() const BOOST_NOEXCEPT { return len_; }
          BOOST_CONSTEXPR bool empty()         const BOOST_NOEXCEPT { return len_ == 0; }
  
          // element access
          BOOST_CONSTEXPR const_reference operator[](size_type pos) const BOOST_NOEXCEPT { return ptr_[pos]; }
  
          BOOST_CONSTEXPR const_reference at(size_t pos) const {
              return pos >= len_ ? BOOST_THROW_EXCEPTION(std::out_of_range("boost::string_view::at")), ptr_[0] : ptr_[pos];
              }
  
          BOOST_CONSTEXPR const_reference front() const                { return ptr_[0]; }
          BOOST_CONSTEXPR const_reference back()  const                { return ptr_[len_-1]; }
          BOOST_CONSTEXPR const_pointer data()    const BOOST_NOEXCEPT { return ptr_; }
  
          // modifiers
          void clear() BOOST_NOEXCEPT { len_ = 0; }          // Boost extension
  
          BOOST_CXX14_CONSTEXPR void remove_prefix(size_type n) {
              if ( n > len_ )
                  n = len_;
              ptr_ += n;
              len_ -= n;
              }
  
          BOOST_CXX14_CONSTEXPR void remove_suffix(size_type n) {
              if ( n > len_ )
                  n = len_;
              len_ -= n;
              }
  
          BOOST_CXX14_CONSTEXPR void swap(basic_string_view& s) BOOST_NOEXCEPT {
              std::swap(ptr_, s.ptr_);
              std::swap(len_, s.len_);
              }
  
          // basic_string_view string operations
  #ifndef BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
          template<typename Allocator>
          explicit operator std::basic_string<charT, traits, Allocator>() const {
              return std::basic_string<charT, traits, Allocator>(begin(), end());
              }
  #endif
  
  #ifndef BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS
          template<typename Allocator = std::allocator<charT> >
          std::basic_string<charT, traits, Allocator> to_string(const Allocator& a = Allocator()) const {
              return std::basic_string<charT, traits, Allocator>(begin(), end(), a);
              }
  #else
          std::basic_string<charT, traits> to_string() const {
              return std::basic_string<charT, traits>(begin(), end());
              }
  
          template<typename Allocator>
          std::basic_string<charT, traits, Allocator> to_string(const Allocator& a) const {
              return std::basic_string<charT, traits, Allocator>(begin(), end(), a);
              }
  #endif
  
          size_type copy(charT* s, size_type n, size_type pos=0) const {
              if (pos > size())
                  BOOST_THROW_EXCEPTION(std::out_of_range("string_view::copy" ));
              size_type rlen = (std::min)(n, len_ - pos);
              traits_type::copy(s, data() + pos, rlen);
              return rlen;
              }
  
          BOOST_CXX14_CONSTEXPR basic_string_view substr(size_type pos, size_type n=npos) const {
              if ( pos > size())
                  BOOST_THROW_EXCEPTION( std::out_of_range ( "string_view::substr" ) );
              return basic_string_view(data() + pos, (std::min)(size() - pos, n));
              }
  
          BOOST_CXX14_CONSTEXPR int compare(basic_string_view x) const BOOST_NOEXCEPT {
              const int cmp = traits::compare(ptr_, x.ptr_, (std::min)(len_, x.len_));
              return cmp != 0 ? cmp : (len_ == x.len_ ? 0 : len_ < x.len_ ? -1 : 1);
              }
  
          BOOST_CXX14_CONSTEXPR int compare(size_type pos1, size_type n1, basic_string_view x)
            const BOOST_NOEXCEPT {
              return substr(pos1, n1).compare(x);
              }
  
          BOOST_CXX14_CONSTEXPR int compare(size_type pos1, size_type n1,
            basic_string_view x, size_type pos2, size_type n2) const {
              return substr(pos1, n1).compare(x.substr(pos2, n2));
              }
  
          BOOST_CXX14_CONSTEXPR int compare(const charT* x) const {
              return compare(basic_string_view(x));
              }
  
          BOOST_CXX14_CONSTEXPR int compare(size_type pos1, size_type n1, const charT* x) const {
              return substr(pos1, n1).compare(basic_string_view(x));
              }
  
          BOOST_CXX14_CONSTEXPR int compare(size_type pos1, size_type n1,
            const charT* x, size_type n2) const {
              return substr(pos1, n1).compare(basic_string_view(x, n2));
              }
  
          //  Searches
          BOOST_CONSTEXPR bool starts_with(charT c) const BOOST_NOEXCEPT {              // Boost extension
              return !empty() && traits::eq(c, front());
              }
  
          BOOST_CONSTEXPR bool starts_with(basic_string_view x) const BOOST_NOEXCEPT {  // Boost extension
              return len_ >= x.len_ && traits::compare(ptr_, x.ptr_, x.len_) == 0;
              }
  
          BOOST_CONSTEXPR bool ends_with(charT c) const BOOST_NOEXCEPT {                // Boost extension
              return !empty() && traits::eq(c, back());
              }
  
          BOOST_CONSTEXPR bool ends_with(basic_string_view x) const BOOST_NOEXCEPT {    // Boost extension
              return len_ >= x.len_ &&
                 traits::compare(ptr_ + len_ - x.len_, x.ptr_, x.len_) == 0;
              }
  
          //  find
          BOOST_CXX14_CONSTEXPR size_type find(basic_string_view s, size_type pos = 0) const BOOST_NOEXCEPT {
              if (pos > size())
                return npos;
              if (s.empty())
                return pos;
              if (s.size() > size() - pos)
                  return npos;
              const charT* cur = ptr_ + pos;
              const charT* last = cend() - s.size() + 1;
              for (; cur != last ; ++cur) {
                  cur = traits::find(cur, last - cur, s[0]);
                  if (!cur)
                      return npos;
                  if (traits::compare(cur, s.cbegin(), s.size()) == 0)
                      return cur - ptr_;
              }
              return npos;
              }
          BOOST_CXX14_CONSTEXPR size_type find(charT c, size_type pos = 0) const BOOST_NOEXCEPT {
              if (pos > size())
                return npos;
              const charT* ret_ptr = traits::find(ptr_ + pos, len_ - pos, c);
              if (ret_ptr)
                return ret_ptr - ptr_;
              return npos;
              }
          BOOST_CXX14_CONSTEXPR size_type find(const charT* s, size_type pos, size_type n) const BOOST_NOEXCEPT
              { return find(basic_string_view(s, n), pos); }
          BOOST_CXX14_CONSTEXPR size_type find(const charT* s, size_type pos = 0) const BOOST_NOEXCEPT
              { return find(basic_string_view(s), pos); }
  
          //  rfind
          BOOST_CXX14_CONSTEXPR size_type rfind(basic_string_view s, size_type pos = npos) const BOOST_NOEXCEPT {
              if (len_ < s.len_)
                return npos;
              if (pos > len_ - s.len_)
                pos = len_ - s.len_;
              if (s.len_ == 0u)     // an empty string is always found
                return pos;
              for (const charT* cur = ptr_ + pos; ; --cur) {
                  if (traits::compare(cur, s.ptr_, s.len_) == 0)
                    return cur - ptr_;
                  if (cur == ptr_)
                    return npos;
                  };
              }
          BOOST_CXX14_CONSTEXPR size_type rfind(charT c, size_type pos = npos) const BOOST_NOEXCEPT
              { return rfind(basic_string_view(&c, 1), pos); }
          BOOST_CXX14_CONSTEXPR size_type rfind(const charT* s, size_type pos, size_type n) const BOOST_NOEXCEPT
              { return rfind(basic_string_view(s, n), pos); }
          BOOST_CXX14_CONSTEXPR size_type rfind(const charT* s, size_type pos = npos) const BOOST_NOEXCEPT
              { return rfind(basic_string_view(s), pos); }
  
          //  find_first_of
          BOOST_CXX14_CONSTEXPR size_type find_first_of(basic_string_view s, size_type pos = 0) const BOOST_NOEXCEPT {
              if (pos >= len_ || s.len_ == 0)
                return npos;
              const_iterator iter = std::find_first_of
                  (this->cbegin () + pos, this->cend (), s.cbegin (), s.cend (), traits::eq);
              return iter == this->cend () ? npos : std::distance ( this->cbegin (), iter );
              }
          BOOST_CXX14_CONSTEXPR size_type find_first_of(charT c, size_type pos = 0) const BOOST_NOEXCEPT
              { return find(c, pos); }
          BOOST_CXX14_CONSTEXPR size_type find_first_of(const charT* s, size_type pos, size_type n) const BOOST_NOEXCEPT
              { return find_first_of(basic_string_view(s, n), pos); }
          BOOST_CXX14_CONSTEXPR size_type find_first_of(const charT* s, size_type pos = 0) const BOOST_NOEXCEPT
              { return find_first_of(basic_string_view(s), pos); }
  
          //  find_last_of
          BOOST_CXX14_CONSTEXPR size_type find_last_of(basic_string_view s, size_type pos = npos) const BOOST_NOEXCEPT {
              if (s.len_ == 0u)
                return npos;
              if (pos >= len_)
                pos = 0;
              else
                pos = len_ - (pos+1);
              const_reverse_iterator iter = std::find_first_of
                  ( this->crbegin () + pos, this->crend (), s.cbegin (), s.cend (), traits::eq );
              return iter == this->crend () ? npos : reverse_distance ( this->crbegin (), iter);
              }
          BOOST_CXX14_CONSTEXPR size_type find_last_of(charT c, size_type pos = npos) const BOOST_NOEXCEPT
              { return find_last_of(basic_string_view(&c, 1), pos); }
          BOOST_CXX14_CONSTEXPR size_type find_last_of(const charT* s, size_type pos, size_type n) const BOOST_NOEXCEPT
              { return find_last_of(basic_string_view(s, n), pos); }
          BOOST_CXX14_CONSTEXPR size_type find_last_of(const charT* s, size_type pos = npos) const BOOST_NOEXCEPT
              { return find_last_of(basic_string_view(s), pos); }
  
          //  find_first_not_of
          BOOST_CXX14_CONSTEXPR size_type find_first_not_of(basic_string_view s, size_type pos = 0) const BOOST_NOEXCEPT {
              if (pos >= len_)
                return npos;
              if (s.len_ == 0)
                return pos;
              const_iterator iter = find_not_of ( this->cbegin () + pos, this->cend (), s );
              return iter == this->cend () ? npos : std::distance ( this->cbegin (), iter );
              }
          BOOST_CXX14_CONSTEXPR size_type find_first_not_of(charT c, size_type pos = 0) const BOOST_NOEXCEPT
              { return find_first_not_of(basic_string_view(&c, 1), pos); }
          BOOST_CXX14_CONSTEXPR size_type find_first_not_of(const charT* s, size_type pos, size_type n) const BOOST_NOEXCEPT
              { return find_first_not_of(basic_string_view(s, n), pos); }
          BOOST_CXX14_CONSTEXPR size_type find_first_not_of(const charT* s, size_type pos = 0) const BOOST_NOEXCEPT
              { return find_first_not_of(basic_string_view(s), pos); }
  
          //  find_last_not_of
          BOOST_CXX14_CONSTEXPR size_type find_last_not_of(basic_string_view s, size_type pos = npos) const BOOST_NOEXCEPT {
              if (pos >= len_)
                pos = len_ - 1;
              if (s.len_ == 0u)
                return pos;
              pos = len_ - (pos+1);
              const_reverse_iterator iter = find_not_of ( this->crbegin () + pos, this->crend (), s );
              return iter == this->crend () ? npos : reverse_distance ( this->crbegin (), iter );
              }
          BOOST_CXX14_CONSTEXPR size_type find_last_not_of(charT c, size_type pos = npos) const BOOST_NOEXCEPT
              { return find_last_not_of(basic_string_view(&c, 1), pos); }
          BOOST_CXX14_CONSTEXPR size_type find_last_not_of(const charT* s, size_type pos, size_type n) const BOOST_NOEXCEPT
              { return find_last_not_of(basic_string_view(s, n), pos); }
          BOOST_CXX14_CONSTEXPR size_type find_last_not_of(const charT* s, size_type pos = npos) const BOOST_NOEXCEPT
              { return find_last_not_of(basic_string_view(s), pos); }
  
      private:
          template <typename r_iter>
          size_type reverse_distance(r_iter first, r_iter last) const BOOST_NOEXCEPT {
          // Portability note here: std::distance is not NOEXCEPT, but calling it with a string_view::reverse_iterator will not throw.
              return len_ - 1 - std::distance ( first, last );
              }
  
          template <typename Iterator>
          Iterator find_not_of(Iterator first, Iterator last, basic_string_view s) const BOOST_NOEXCEPT {
              for (; first != last ; ++first)
                  if ( 0 == traits::find(s.ptr_, s.len_, *first))
                      return first;
              return last;
              }
  
          const charT *ptr_;
          std::size_t len_;
          };
  
  
  //  Comparison operators
  //  Equality
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator==(basic_string_view<charT, traits> x,
                             basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          if (x.size () != y.size ()) return false;
          return x.compare(y) == 0;
          }
  
  //  Inequality
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator!=(basic_string_view<charT, traits> x,
                             basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          if ( x.size () != y.size ()) return true;
          return x.compare(y) != 0;
          }
  
  //  Less than
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator<(basic_string_view<charT, traits> x,
                            basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return x.compare(y) < 0;
          }
  
  //  Greater than
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator>(basic_string_view<charT, traits> x,
                            basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return x.compare(y) > 0;
          }
  
  //  Less than or equal to
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator<=(basic_string_view<charT, traits> x,
                             basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return x.compare(y) <= 0;
          }
  
  //  Greater than or equal to
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator>=(basic_string_view<charT, traits> x,
                             basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return x.compare(y) >= 0;
          }
  
  // "sufficient additional overloads of comparison functions"
      template<typename charT, typename traits, typename Allocator>
      inline BOOST_CXX14_CONSTEXPR bool operator==(basic_string_view<charT, traits> x,
                       const std::basic_string<charT, traits, Allocator> & y) BOOST_NOEXCEPT {
          return x == basic_string_view<charT, traits>(y);
          }
  
      template<typename charT, typename traits, typename Allocator>
      inline BOOST_CXX14_CONSTEXPR bool operator==(const std::basic_string<charT, traits, Allocator> & x,
                                   basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return basic_string_view<charT, traits>(x) == y;
          }
  
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator==(basic_string_view<charT, traits> x,
                                                const charT * y) BOOST_NOEXCEPT {
          return x == basic_string_view<charT, traits>(y);
          }
  
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator==(const charT * x,
                             basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return basic_string_view<charT, traits>(x) == y;
          }
  
      template<typename charT, typename traits, typename Allocator>
      inline BOOST_CXX14_CONSTEXPR bool operator!=(basic_string_view<charT, traits> x,
                       const std::basic_string<charT, traits, Allocator> & y) BOOST_NOEXCEPT {
          return x != basic_string_view<charT, traits>(y);
          }
  
      template<typename charT, typename traits, typename Allocator>
      inline BOOST_CXX14_CONSTEXPR bool operator!=(const std::basic_string<charT, traits, Allocator> & x,
                                   basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return basic_string_view<charT, traits>(x) != y;
          }
  
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator!=(basic_string_view<charT, traits> x,
                             const charT * y) BOOST_NOEXCEPT {
          return x != basic_string_view<charT, traits>(y);
          }
  
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator!=(const charT * x,
                             basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return basic_string_view<charT, traits>(x) != y;
          }
  
      template<typename charT, typename traits, typename Allocator>
      inline BOOST_CXX14_CONSTEXPR bool operator<(basic_string_view<charT, traits> x,
                      const std::basic_string<charT, traits, Allocator> & y) BOOST_NOEXCEPT {
          return x < basic_string_view<charT, traits>(y);
          }
  
      template<typename charT, typename traits, typename Allocator>
      inline BOOST_CXX14_CONSTEXPR bool operator<(const std::basic_string<charT, traits, Allocator> & x,
                                  basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return basic_string_view<charT, traits>(x) < y;
          }
  
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator<(basic_string_view<charT, traits> x,
                            const charT * y) BOOST_NOEXCEPT {
          return x < basic_string_view<charT, traits>(y);
          }
  
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator<(const charT * x,
                            basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return basic_string_view<charT, traits>(x) < y;
          }
  
      template<typename charT, typename traits, typename Allocator>
      inline BOOST_CXX14_CONSTEXPR bool operator>(basic_string_view<charT, traits> x,
                      const std::basic_string<charT, traits, Allocator> & y) BOOST_NOEXCEPT {
          return x > basic_string_view<charT, traits>(y);
          }
  
      template<typename charT, typename traits, typename Allocator>
      inline BOOST_CXX14_CONSTEXPR bool operator>(const std::basic_string<charT, traits, Allocator> & x,
                                  basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return basic_string_view<charT, traits>(x) > y;
          }
  
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator>(basic_string_view<charT, traits> x,
                            const charT * y) BOOST_NOEXCEPT {
          return x > basic_string_view<charT, traits>(y);
          }
  
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator>(const charT * x,
                            basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return basic_string_view<charT, traits>(x) > y;
          }
  
      template<typename charT, typename traits, typename Allocator>
      inline BOOST_CXX14_CONSTEXPR bool operator<=(basic_string_view<charT, traits> x,
                       const std::basic_string<charT, traits, Allocator> & y) BOOST_NOEXCEPT {
          return x <= basic_string_view<charT, traits>(y);
          }
  
      template<typename charT, typename traits, typename Allocator>
      inline BOOST_CXX14_CONSTEXPR bool operator<=(const std::basic_string<charT, traits, Allocator> & x,
                                   basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return basic_string_view<charT, traits>(x) <= y;
          }
  
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator<=(basic_string_view<charT, traits> x,
                             const charT * y) BOOST_NOEXCEPT {
          return x <= basic_string_view<charT, traits>(y);
          }
  
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator<=(const charT * x,
                             basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return basic_string_view<charT, traits>(x) <= y;
          }
  
      template<typename charT, typename traits, typename Allocator>
      inline BOOST_CXX14_CONSTEXPR bool operator>=(basic_string_view<charT, traits> x,
                       const std::basic_string<charT, traits, Allocator> & y) BOOST_NOEXCEPT {
          return x >= basic_string_view<charT, traits>(y);
          }
  
      template<typename charT, typename traits, typename Allocator>
      inline BOOST_CXX14_CONSTEXPR bool operator>=(const std::basic_string<charT, traits, Allocator> & x,
                                   basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return basic_string_view<charT, traits>(x) >= y;
          }
  
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator>=(basic_string_view<charT, traits> x,
                             const charT * y) BOOST_NOEXCEPT {
          return x >= basic_string_view<charT, traits>(y);
          }
  
      template<typename charT, typename traits>
      inline BOOST_CXX14_CONSTEXPR bool operator>=(const charT * x,
                             basic_string_view<charT, traits> y) BOOST_NOEXCEPT {
          return basic_string_view<charT, traits>(x) >= y;
          }
  
      // Inserter
      template<class charT, class traits>
      inline std::basic_ostream<charT, traits>&
      operator<<(std::basic_ostream<charT, traits>& os,
        const basic_string_view<charT,traits>& str) {
          return boost::io::ostream_put(os, str.data(), str.size());
          }
  
  #if 0
      // numeric conversions
      //
      //  These are short-term implementations.
      //  In a production environment, I would rather avoid the copying.
      //
      inline int stoi (string_view str, size_t* idx=0, int base=10) {
          return std::stoi ( std::string(str), idx, base );
          }
  
      inline long stol (string_view str, size_t* idx=0, int base=10) {
          return std::stol ( std::string(str), idx, base );
          }
  
      inline unsigned long stoul (string_view str, size_t* idx=0, int base=10) {
          return std::stoul ( std::string(str), idx, base );
          }
  
      inline long long stoll (string_view str, size_t* idx=0, int base=10) {
          return std::stoll ( std::string(str), idx, base );
          }
  
      inline unsigned long long stoull (string_view str, size_t* idx=0, int base=10) {
          return std::stoull ( std::string(str), idx, base );
          }
  
      inline float stof (string_view str, size_t* idx=0) {
          return std::stof ( std::string(str), idx );
          }
  
      inline double stod (string_view str, size_t* idx=0) {
          return std::stod ( std::string(str), idx );
          }
  
      inline long double stold (string_view str, size_t* idx=0)  {
          return std::stold ( std::string(str), idx );
          }
  
      inline int  stoi (wstring_view str, size_t* idx=0, int base=10) {
          return std::stoi ( std::wstring(str), idx, base );
          }
  
      inline long stol (wstring_view str, size_t* idx=0, int base=10) {
          return std::stol ( std::wstring(str), idx, base );
          }
  
      inline unsigned long stoul (wstring_view str, size_t* idx=0, int base=10) {
          return std::stoul ( std::wstring(str), idx, base );
          }
  
      inline long long stoll (wstring_view str, size_t* idx=0, int base=10) {
          return std::stoll ( std::wstring(str), idx, base );
          }
  
      inline unsigned long long stoull (wstring_view str, size_t* idx=0, int base=10) {
          return std::stoull ( std::wstring(str), idx, base );
          }
  
      inline float  stof (wstring_view str, size_t* idx=0) {
          return std::stof ( std::wstring(str), idx );
          }
  
      inline double stod (wstring_view str, size_t* idx=0) {
          return std::stod ( std::wstring(str), idx );
          }
  
      inline long double stold (wstring_view str, size_t* idx=0) {
          return std::stold ( std::wstring(str), idx );
          }
  #endif
  
      // Forward declaration of Boost.ContainerHash function
      template <class It> std::size_t hash_range(It, It);
  
      template <class charT, class traits>
      std::size_t hash_value(basic_string_view<charT, traits> s) {
          return boost::hash_range(s.begin(), s.end());
          }
  }
  
  #if 0
  namespace std {
      // Hashing
      template<> struct hash<boost::string_view>;
      template<> struct hash<boost::u16string_view>;
      template<> struct hash<boost::u32string_view>;
      template<> struct hash<boost::wstring_view>;
  }
  #endif
  
  #endif
  