Class StringRef

extras/tests/catch/catch.hpp:606–675

A non-owning string class (similar to the forthcoming std::string_view) Note that, because a StringRef may be a substring of another string, it may not be null terminated.

    /// Note that, because a StringRef may be a substring of another string,
    /// it may not be null terminated.
    class StringRef {
    public:
        using size_type = std::size_t;
        using const_iterator = const char*;

    private:
        static constexpr char const* const s_empty = "";

        char const* m_start = s_empty;
        size_type m_size = 0;

    public: // construction
        constexpr StringRef() noexcept = default;

        StringRef( char const* rawChars ) noexcept;

        constexpr StringRef( char const* rawChars, size_type size ) noexcept
        :   m_start( rawChars ),
            m_size( size )
        {}

        StringRef( std::string const& stdString ) noexcept
        :   m_start( stdString.c_str() ),
            m_size( stdString.size() )
        {}

        explicit operator std::string() const {
            return std::string(m_start, m_size);
        }

    public: // operators
        auto operator == ( StringRef const& other ) const noexcept -> bool;
        auto operator != (StringRef const& other) const noexcept -> bool {
            return !(*this == other);
        }

        auto operator[] ( size_type index ) const noexcept -> char {
            assert(index < m_size);
            return m_start[index];
        }

    public: // named queries
        constexpr auto empty() const noexcept -> bool {
            return m_size == 0;
        }
        constexpr auto size() const noexcept -> size_type {
            return m_size;
        }

        // Returns the current start pointer. If the StringRef is not
        // null-terminated, throws std::domain_exception
        auto c_str() const -> char const*;

    public: // substrings and searches
        // Returns a substring of [start, start + length).
        // If start + length > size(), then the substring is [start, size()).
        // If start > size(), then the substring is empty.
        auto substr( size_type start, size_type length ) const noexcept -> StringRef;