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diff --git a/include/jsoncons/json_visitor2.hpp b/include/jsoncons/json_visitor2.hpp
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index 0000000..26096aa
--- /dev/null
+++ b/include/jsoncons/json_visitor2.hpp
@@ -0,0 +1,2079 @@
+// Copyright 2018 Daniel Parker
+// Distributed under the Boost license, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// See https://github.com/danielaparker/jsoncons for latest version
+
+#ifndef JSONCONS_JSON_VISITOR2_HPP
+#define JSONCONS_JSON_VISITOR2_HPP
+
+#include <jsoncons/json_visitor.hpp>
+#include <jsoncons/json_encoder.hpp>
+
+namespace jsoncons { 
+
+    template <class CharT, class Allocator = std::allocator<char>>
+    class basic_json_visitor2_to_visitor_adaptor;
+
+    template <class CharT>
+    class basic_json_visitor2 
+    {
+        template <class Ch, class Allocator>
+        friend class basic_json_visitor2_to_visitor_adaptor;
+    public:
+        using char_type = CharT;
+        using char_traits_type = std::char_traits<char_type>;
+
+        using string_view_type = jsoncons::basic_string_view<char_type,char_traits_type>;
+
+        basic_json_visitor2(basic_json_visitor2&&) = default;
+
+        basic_json_visitor2& operator=(basic_json_visitor2&&) = default;
+
+        basic_json_visitor2() = default;
+
+        virtual ~basic_json_visitor2() noexcept = default;
+
+        void flush()
+        {
+            visit_flush();
+        }
+
+        bool begin_object(semantic_tag tag=semantic_tag::none,
+                          const ser_context& context=ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_begin_object(tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool begin_object(std::size_t length, 
+                          semantic_tag tag=semantic_tag::none, 
+                          const ser_context& context = ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_begin_object(length, tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool end_object(const ser_context& context = ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_end_object(context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool begin_array(semantic_tag tag=semantic_tag::none,
+                         const ser_context& context=ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_begin_array(tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool begin_array(std::size_t length, 
+                         semantic_tag tag=semantic_tag::none,
+                         const ser_context& context=ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_begin_array(length, tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool end_array(const ser_context& context=ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_end_array(context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool key(const string_view_type& name, const ser_context& context=ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_string(name, semantic_tag::none, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool null_value(semantic_tag tag = semantic_tag::none,
+                        const ser_context& context=ser_context()) 
+        {
+            std::error_code ec;
+            bool more = visit_null(tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool bool_value(bool value, 
+                        semantic_tag tag = semantic_tag::none,
+                        const ser_context& context=ser_context()) 
+        {
+            std::error_code ec;
+            bool more = visit_bool(value, tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool string_value(const string_view_type& value, 
+                          semantic_tag tag = semantic_tag::none, 
+                          const ser_context& context=ser_context()) 
+        {
+            std::error_code ec;
+            bool more = visit_string(value, tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        template <class Source>
+        bool byte_string_value(const Source& b, 
+                               semantic_tag tag=semantic_tag::none, 
+                               const ser_context& context=ser_context(),
+                               typename std::enable_if<type_traits::is_byte_sequence<Source>::value,int>::type = 0)
+        {
+            std::error_code ec;
+            bool more = visit_byte_string(byte_string_view(reinterpret_cast<const uint8_t*>(b.data()),b.size()), tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        template <class Source>
+        bool byte_string_value(const Source& b, 
+                               uint64_t ext_tag, 
+                               const ser_context& context=ser_context(),
+                               typename std::enable_if<type_traits::is_byte_sequence<Source>::value,int>::type = 0)
+        {
+            std::error_code ec;
+            bool more = visit_byte_string(byte_string_view(reinterpret_cast<const uint8_t*>(b.data()),b.size()), ext_tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool uint64_value(uint64_t value, 
+                          semantic_tag tag = semantic_tag::none, 
+                          const ser_context& context=ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_uint64(value, tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool int64_value(int64_t value, 
+                         semantic_tag tag = semantic_tag::none, 
+                         const ser_context& context=ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_int64(value, tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool half_value(uint16_t value, 
+                        semantic_tag tag = semantic_tag::none, 
+                        const ser_context& context=ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_half(value, tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool double_value(double value, 
+                          semantic_tag tag = semantic_tag::none, 
+                          const ser_context& context=ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_double(value, tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool begin_object(semantic_tag tag,
+                          const ser_context& context,
+                          std::error_code& ec)
+        {
+            return visit_begin_object(tag, context, ec);
+        }
+
+        bool begin_object(std::size_t length, 
+                          semantic_tag tag, 
+                          const ser_context& context,
+                          std::error_code& ec)
+        {
+            return visit_begin_object(length, tag, context, ec);
+        }
+
+        bool end_object(const ser_context& context, std::error_code& ec)
+        {
+            return visit_end_object(context, ec);
+        }
+
+        bool begin_array(semantic_tag tag, const ser_context& context, std::error_code& ec)
+        {
+            return visit_begin_array(tag, context, ec);
+        }
+
+        bool begin_array(std::size_t length, semantic_tag tag, const ser_context& context, std::error_code& ec)
+        {
+            return visit_begin_array(length, tag, context, ec);
+        }
+
+        bool end_array(const ser_context& context, std::error_code& ec)
+        {
+            return visit_end_array(context, ec);
+        }
+
+        bool key(const string_view_type& name, const ser_context& context, std::error_code& ec)
+        {
+            return visit_string(name, semantic_tag::none, context, ec);
+        }
+
+        bool null_value(semantic_tag tag,
+                        const ser_context& context,
+                        std::error_code& ec) 
+        {
+            return visit_null(tag, context, ec);
+        }
+
+        bool bool_value(bool value, 
+                        semantic_tag tag,
+                        const ser_context& context,
+                        std::error_code& ec) 
+        {
+            return visit_bool(value, tag, context, ec);
+        }
+
+        bool string_value(const string_view_type& value, 
+                          semantic_tag tag, 
+                          const ser_context& context,
+                          std::error_code& ec) 
+        {
+            return visit_string(value, tag, context, ec);
+        }
+
+        template <class Source>
+        bool byte_string_value(const Source& b, 
+                               semantic_tag tag, 
+                               const ser_context& context,
+                               std::error_code& ec,
+                               typename std::enable_if<type_traits::is_byte_sequence<Source>::value,int>::type = 0)
+        {
+            return visit_byte_string(byte_string_view(reinterpret_cast<const uint8_t*>(b.data()),b.size()), tag, context, ec);
+        }
+
+        template <class Source>
+        bool byte_string_value(const Source& b, 
+                               uint64_t ext_tag, 
+                               const ser_context& context,
+                               std::error_code& ec,
+                               typename std::enable_if<type_traits::is_byte_sequence<Source>::value,int>::type = 0)
+        {
+            return visit_byte_string(byte_string_view(reinterpret_cast<const uint8_t*>(b.data()),b.size()), ext_tag, context, ec);
+        }
+
+        bool uint64_value(uint64_t value, 
+                          semantic_tag tag, 
+                          const ser_context& context,
+                          std::error_code& ec)
+        {
+            return visit_uint64(value, tag, context, ec);
+        }
+
+        bool int64_value(int64_t value, 
+                         semantic_tag tag, 
+                         const ser_context& context,
+                         std::error_code& ec)
+        {
+            return visit_int64(value, tag, context, ec);
+        }
+
+        bool half_value(uint16_t value, 
+                        semantic_tag tag, 
+                        const ser_context& context,
+                        std::error_code& ec)
+        {
+            return visit_half(value, tag, context, ec);
+        }
+
+        bool double_value(double value, 
+                          semantic_tag tag, 
+                          const ser_context& context,
+                          std::error_code& ec)
+        {
+            return visit_double(value, tag, context, ec);
+        }
+
+        template <class T>
+        bool typed_array(const jsoncons::span<T>& data, 
+                         semantic_tag tag=semantic_tag::none,
+                         const ser_context& context=ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_typed_array(data, tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        template <class T>
+        bool typed_array(const jsoncons::span<T>& data, 
+                         semantic_tag tag,
+                         const ser_context& context,
+                         std::error_code& ec)
+        {
+            return visit_typed_array(data, tag, context, ec);
+        }
+
+        bool typed_array(half_arg_t, const jsoncons::span<const uint16_t>& s,
+            semantic_tag tag = semantic_tag::none,
+            const ser_context& context = ser_context())
+        {
+            std::error_code ec;
+            bool more = visit_typed_array(half_arg, s, tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool typed_array(half_arg_t, const jsoncons::span<const uint16_t>& s,
+                         semantic_tag tag,
+                         const ser_context& context,
+                         std::error_code& ec)
+        {
+            return visit_typed_array(half_arg, s, tag, context, ec);
+        }
+
+        bool begin_multi_dim(const jsoncons::span<const size_t>& shape,
+                             semantic_tag tag = semantic_tag::multi_dim_row_major,
+                             const ser_context& context=ser_context()) 
+        {
+            std::error_code ec;
+            bool more = visit_begin_multi_dim(shape, tag, context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool begin_multi_dim(const jsoncons::span<const size_t>& shape,
+                             semantic_tag tag,
+                             const ser_context& context,
+                             std::error_code& ec) 
+        {
+            return visit_begin_multi_dim(shape, tag, context, ec);
+        }
+
+        bool end_multi_dim(const ser_context& context=ser_context()) 
+        {
+            std::error_code ec;
+            bool more = visit_end_multi_dim(context, ec);
+            if (ec)
+            {
+                JSONCONS_THROW(ser_error(ec, context.line(), context.column()));
+            }
+            return more;
+        }
+
+        bool end_multi_dim(const ser_context& context,
+                           std::error_code& ec) 
+        {
+            return visit_end_multi_dim(context, ec);
+        }
+
+    private:
+
+        virtual void visit_flush() = 0;
+
+        virtual bool visit_begin_object(semantic_tag tag, 
+                                        const ser_context& context, 
+                                        std::error_code& ec) = 0;
+
+        virtual bool visit_begin_object(std::size_t /*length*/, 
+                                        semantic_tag tag, 
+                                        const ser_context& context, 
+                                        std::error_code& ec)
+        {
+            return visit_begin_object(tag, context, ec);
+        }
+
+        virtual bool visit_end_object(const ser_context& context, 
+                                      std::error_code& ec) = 0;
+
+        virtual bool visit_begin_array(semantic_tag tag, 
+                                       const ser_context& context, 
+                                       std::error_code& ec) = 0;
+
+        virtual bool visit_begin_array(std::size_t /*length*/, 
+                                       semantic_tag tag, 
+                                       const ser_context& context, 
+                                       std::error_code& ec)
+        {
+            return visit_begin_array(tag, context, ec);
+        }
+
+        virtual bool visit_end_array(const ser_context& context, 
+                                     std::error_code& ec) = 0;
+
+        virtual bool visit_null(semantic_tag tag, 
+                             const ser_context& context, 
+                             std::error_code& ec) = 0;
+
+        virtual bool visit_bool(bool value, 
+                             semantic_tag tag, 
+                             const ser_context& context, 
+                             std::error_code&) = 0;
+
+        virtual bool visit_string(const string_view_type& value, 
+                               semantic_tag tag, 
+                               const ser_context& context, 
+                               std::error_code& ec) = 0;
+
+        virtual bool visit_byte_string(const byte_string_view& value, 
+                                    semantic_tag tag, 
+                                    const ser_context& context,
+                                    std::error_code& ec) = 0;
+
+        virtual bool visit_byte_string(const byte_string_view& value, 
+                                       uint64_t /*ext_tag*/, 
+                                       const ser_context& context,
+                                       std::error_code& ec) 
+        {
+            return visit_byte_string(value, semantic_tag::none, context, ec);
+        }
+
+        virtual bool visit_uint64(uint64_t value, 
+                               semantic_tag tag, 
+                               const ser_context& context,
+                               std::error_code& ec) = 0;
+
+        virtual bool visit_int64(int64_t value, 
+                              semantic_tag tag,
+                              const ser_context& context,
+                              std::error_code& ec) = 0;
+
+        virtual bool visit_half(uint16_t value, 
+                             semantic_tag tag,
+                             const ser_context& context,
+                             std::error_code& ec)
+        {
+            return visit_double(binary::decode_half(value),
+                             tag,
+                             context,
+                             ec);
+        }
+
+        virtual bool visit_double(double value, 
+                               semantic_tag tag,
+                               const ser_context& context,
+                               std::error_code& ec) = 0;
+
+        virtual bool visit_typed_array(const jsoncons::span<const uint8_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec)  
+        {
+            bool more = begin_array(s.size(), tag, context, ec);
+            for (auto p = s.begin(); more && p != s.end(); ++p)
+            {
+                more = uint64_value(*p, semantic_tag::none, context, ec);
+            }
+            if (more)
+            {
+                more = end_array(context, ec);
+            }
+            return more;
+        }
+
+        virtual bool visit_typed_array(const jsoncons::span<const uint16_t>& s, 
+                                    semantic_tag tag, 
+                                    const ser_context& context, 
+                                    std::error_code& ec)  
+        {
+            bool more = begin_array(s.size(), tag, context, ec);
+            for (auto p = s.begin(); more && p != s.end(); ++p)
+            {
+                more = uint64_value(*p, semantic_tag::none, context, ec);
+            }
+            if (more)
+            {
+                more = end_array(context, ec);
+            }
+            return more;
+        }
+
+        virtual bool visit_typed_array(const jsoncons::span<const uint32_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec) 
+        {
+            bool more = begin_array(s.size(), tag, context, ec);
+            for (auto p = s.begin(); more && p != s.end(); ++p)
+            {
+                more = uint64_value(*p, semantic_tag::none, context, ec);
+            }
+            if (more)
+            {
+                more = end_array(context, ec);
+            }
+            return more;
+        }
+
+        virtual bool visit_typed_array(const jsoncons::span<const uint64_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec) 
+        {
+            bool more = begin_array(s.size(), tag, context, ec);
+            for (auto p = s.begin(); more && p != s.end(); ++p)
+            {
+                more = uint64_value(*p,semantic_tag::none,context, ec);
+            }
+            if (more)
+            {
+                more = end_array(context, ec);
+            }
+            return more;
+        }
+
+        virtual bool visit_typed_array(const jsoncons::span<const int8_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec)  
+        {
+            bool more = begin_array(s.size(), tag,context, ec);
+            for (auto p = s.begin(); more && p != s.end(); ++p)
+            {
+                more = int64_value(*p,semantic_tag::none,context, ec);
+            }
+            if (more)
+            {
+                more = end_array(context, ec);
+            }
+            return more;
+        }
+
+        virtual bool visit_typed_array(const jsoncons::span<const int16_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec)  
+        {
+            bool more = begin_array(s.size(), tag,context, ec);
+            for (auto p = s.begin(); more && p != s.end(); ++p)
+            {
+                more = int64_value(*p,semantic_tag::none,context, ec);
+            }
+            if (more)
+            {
+                more = end_array(context, ec);
+            }
+            return more;
+        }
+
+        virtual bool visit_typed_array(const jsoncons::span<const int32_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec)  
+        {
+            bool more = begin_array(s.size(), tag,context, ec);
+            for (auto p = s.begin(); more && p != s.end(); ++p)
+            {
+                more = int64_value(*p,semantic_tag::none,context, ec);
+            }
+            if (more)
+            {
+                more = end_array(context, ec);
+            }
+            return more;
+        }
+
+        virtual bool visit_typed_array(const jsoncons::span<const int64_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec)  
+        {
+            bool more = begin_array(s.size(), tag,context, ec);
+            for (auto p = s.begin(); more && p != s.end(); ++p)
+            {
+                more = int64_value(*p,semantic_tag::none,context, ec);
+            }
+            if (more)
+            {
+                more = end_array(context, ec);
+            }
+            return more;
+        }
+
+        virtual bool visit_typed_array(half_arg_t, 
+                                    const jsoncons::span<const uint16_t>& s, 
+                                    semantic_tag tag, 
+                                    const ser_context& context, 
+                                    std::error_code& ec)  
+        {
+            bool more = begin_array(s.size(), tag, context, ec);
+            for (auto p = s.begin(); more && p != s.end(); ++p)
+            {
+                more = half_value(*p, semantic_tag::none, context, ec);
+            }
+            if (more)
+            {
+                more = end_array(context, ec);
+            }
+            return more;
+        }
+
+        virtual bool visit_typed_array(const jsoncons::span<const float>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec)  
+        {
+            bool more = begin_array(s.size(), tag,context, ec);
+            for (auto p = s.begin(); more && p != s.end(); ++p)
+            {
+                more = double_value(*p,semantic_tag::none,context, ec);
+            }
+            if (more)
+            {
+                more = end_array(context, ec);
+            }
+            return more;
+        }
+
+        virtual bool visit_typed_array(const jsoncons::span<const double>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec)  
+        {
+            bool more = begin_array(s.size(), tag,context, ec);
+            for (auto p = s.begin(); more && p != s.end(); ++p)
+            {
+                more = double_value(*p,semantic_tag::none,context, ec);
+            }
+            if (more)
+            {
+                more = end_array(context, ec);
+            }
+            return more;
+        }
+
+        virtual bool visit_begin_multi_dim(const jsoncons::span<const size_t>& shape,
+                                        semantic_tag tag,
+                                        const ser_context& context, 
+                                        std::error_code& ec) 
+        {
+            bool more = visit_begin_array(2, tag, context, ec);
+            if (more)
+            {
+                more = visit_begin_array(shape.size(), tag, context, ec);
+                for (auto it = shape.begin(); more && it != shape.end(); ++it)
+                {
+                    visit_uint64(*it, semantic_tag::none, context, ec);
+                }
+                if (more)
+                {
+                    more = visit_end_array(context, ec);
+                }
+            }
+            return more;
+        }
+
+        virtual bool visit_end_multi_dim(const ser_context& context,
+                                      std::error_code& ec) 
+        {
+            return visit_end_array(context, ec);
+        }
+    };
+
+ template <class CharT, class Allocator>
+    class basic_json_visitor2_to_visitor_adaptor : public basic_json_visitor2<CharT>
+    {
+    public:
+        using typename basic_json_visitor2<CharT>::char_type;
+        using typename basic_json_visitor2<CharT>::string_view_type;
+    private:
+        using char_allocator_type = typename std::allocator_traits<Allocator>:: template rebind_alloc<char_type>;
+
+        using string_type = std::basic_string<char_type,std::char_traits<char_type>,char_allocator_type>;
+
+        enum class container_t {root, array, object};
+        enum class target_t {destination, buffer};
+
+        struct level
+        {
+        private:
+            target_t state_;
+            container_t type_;
+            int even_odd_;
+            std::size_t count_;
+        public:
+
+            level(target_t state, container_t type) noexcept
+                : state_(state), type_(type), even_odd_(type == container_t::object ? 0 : 1), count_(0)
+            {
+            }
+
+            void advance()
+            {
+                if (!is_key())
+                {
+                    ++count_;
+                }
+                if (is_object())
+                {
+                    even_odd_ = !even_odd_;
+                }
+            }
+
+            bool is_key() const
+            {
+                return even_odd_ == 0;
+            }
+
+            bool is_object() const
+            {
+                return type_ == container_t::object;
+            }
+
+            target_t target() const
+            {
+                return state_;
+            }
+
+            std::size_t count() const
+            {
+                return count_;
+            }
+        };
+        using level_allocator_type = typename std::allocator_traits<Allocator>:: template rebind_alloc<level>;
+
+        basic_default_json_visitor<char_type> default_visitor_;
+        basic_json_visitor<char_type>* destination_;
+        string_type key_;
+        string_type key_buffer_;
+        std::vector<level,level_allocator_type> level_stack_;
+
+        const std::basic_string<char> null_constant = {'n','u','l','l'};
+        const std::basic_string<char> true_constant = { 't','r','u','e' };
+        const std::basic_string<char> false_constant = { 'f', 'a', 'l', 's', 'e' };
+
+        // noncopyable and nonmoveable
+        basic_json_visitor2_to_visitor_adaptor(const basic_json_visitor2_to_visitor_adaptor&) = delete;
+        basic_json_visitor2_to_visitor_adaptor& operator=(const basic_json_visitor2_to_visitor_adaptor&) = delete;
+    public:
+        explicit basic_json_visitor2_to_visitor_adaptor(const Allocator& alloc = Allocator())
+            : default_visitor_(), destination_(std::addressof(default_visitor_)),
+              key_(alloc), key_buffer_(alloc), level_stack_(alloc)
+        {
+            level_stack_.emplace_back(target_t::destination,container_t::root); // root
+        }
+
+        explicit basic_json_visitor2_to_visitor_adaptor(basic_json_visitor<char_type>& visitor, 
+                                                     const Allocator& alloc = Allocator())
+            : destination_(std::addressof(visitor)), 
+              key_(alloc), key_buffer_(alloc), level_stack_(alloc)
+        {
+            level_stack_.emplace_back(target_t::destination,container_t::root); // root
+        }
+
+        void reset()
+        {
+            key_.clear();
+            key_buffer_.clear();
+            level_stack_.clear();
+            level_stack_.emplace_back(target_t::destination,container_t::root); // root
+        }
+
+        basic_json_visitor<char_type>& destination()
+        {
+            return *destination_;
+        }
+
+        void destination(basic_json_visitor<char_type>& dest)
+        {
+            destination_ = std::addressof(dest);
+        }
+
+    private:
+        void visit_flush() override
+        {
+            destination_->flush();
+        }
+
+        bool visit_begin_object(semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            if (level_stack_.back().is_key())
+            {
+                if (level_stack_.back().target() == target_t::buffer && level_stack_.back().count() > 0)
+                {
+                    key_buffer_.push_back(',');
+                }
+                level_stack_.emplace_back(target_t::buffer, container_t::object);
+                key_buffer_.push_back('{');
+                return true;
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        level_stack_.emplace_back(target_t::buffer, container_t::object);
+                        key_buffer_.push_back('{');
+                        return true;
+                    default:
+                        level_stack_.emplace_back(target_t::destination, container_t::object);
+                        return destination_->begin_object(tag, context, ec);
+                }
+            }
+        }
+
+        bool visit_begin_object(std::size_t length, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            if (level_stack_.back().is_key())
+            {
+                if (level_stack_.back().target() == target_t::buffer && level_stack_.back().count() > 0)
+                {
+                    key_buffer_.push_back(',');
+                }
+                level_stack_.emplace_back(target_t::buffer, container_t::object);
+                key_buffer_.push_back('{');
+                return true;
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (!level_stack_.back().is_object() && level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        level_stack_.emplace_back(target_t::buffer, container_t::object);
+                        key_buffer_.push_back('{');
+                        return true;
+                    default:
+                        level_stack_.emplace_back(target_t::destination, container_t::object);
+                        return destination_->begin_object(length, tag, context, ec);
+                }
+            }
+        }
+
+        bool visit_end_object(const ser_context& context, std::error_code& ec) override
+        {
+            bool retval = true;
+            switch (level_stack_.back().target())
+            {
+                case target_t::buffer:
+                    key_buffer_.push_back('}');
+                    JSONCONS_ASSERT(level_stack_.size() > 1);
+                    level_stack_.pop_back();
+                    
+                    if (level_stack_.back().target() == target_t::destination)
+                    {
+                        retval = destination_->key(key_buffer_,context, ec);
+                        key_buffer_.clear();
+                    }
+                    else if (level_stack_.back().is_key())
+                    {
+                        key_buffer_.push_back(':');
+                    }
+                    level_stack_.back().advance();
+                    break;
+                default:
+                    JSONCONS_ASSERT(level_stack_.size() > 1);
+                    level_stack_.pop_back();
+                    level_stack_.back().advance();
+                    retval = destination_->end_object(context, ec);
+                    break;
+            }
+            return retval;
+        }
+
+        bool visit_begin_array(semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            if (level_stack_.back().is_key())
+            {
+                if (level_stack_.back().target() == target_t::buffer && level_stack_.back().count() > 0)
+                {
+                    key_buffer_.push_back(',');
+                }
+                level_stack_.emplace_back(target_t::buffer, container_t::array);
+                key_buffer_.push_back('[');
+                return true;
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (level_stack_.back().is_object() && level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        level_stack_.emplace_back(target_t::buffer, container_t::array);
+                        key_buffer_.push_back('[');
+                        return true;
+                    default:
+                        level_stack_.emplace_back(target_t::destination, container_t::array);
+                        return destination_->begin_array(tag, context, ec);
+                }
+            }
+        }
+
+        bool visit_begin_array(std::size_t length, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            if (level_stack_.back().is_key())
+            {
+                if (level_stack_.back().target() == target_t::buffer && level_stack_.back().count() > 0)
+                {
+                    key_buffer_.push_back(',');
+                }
+                level_stack_.emplace_back(target_t::buffer, container_t::array);
+                key_buffer_.push_back('[');
+                return true;
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (!level_stack_.back().is_object() && level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        level_stack_.emplace_back(target_t::buffer, container_t::array);
+                        key_buffer_.push_back('[');
+                        return true;
+                    default:
+                        level_stack_.emplace_back(target_t::destination, container_t::array);
+                        return destination_->begin_array(length, tag, context, ec);
+                }
+            }
+        }
+
+        bool visit_end_array(const ser_context& context, std::error_code& ec) override
+        {
+            bool retval = true;
+            switch (level_stack_.back().target())
+            {
+                case target_t::buffer:
+                    key_buffer_.push_back(']');
+                    JSONCONS_ASSERT(level_stack_.size() > 1);
+                    level_stack_.pop_back();
+                    if (level_stack_.back().target() == target_t::destination)
+                    {
+                        retval = destination_->key(key_buffer_, context, ec);
+                        key_buffer_.clear();
+                    }
+                    else if (level_stack_.back().is_key())
+                    {
+                        key_buffer_.push_back(':');
+                    }
+                    level_stack_.back().advance();
+                    break;
+                default:
+                    JSONCONS_ASSERT(level_stack_.size() > 1);
+                    level_stack_.pop_back();
+                    level_stack_.back().advance();
+                    retval = destination_->end_array(context, ec);
+                    break;
+            }
+            return retval;
+        }
+
+        bool visit_string(const string_view_type& value,
+                             semantic_tag tag,
+                             const ser_context& context,
+                             std::error_code& ec) override
+        {
+            bool retval = true;
+
+            if (level_stack_.back().is_key())
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.push_back('\"');
+                        key_buffer_.insert(key_buffer_.end(), value.begin(), value.end());
+                        key_buffer_.push_back('\"');
+                        key_buffer_.push_back(':');
+                        retval = true;
+                        break;
+                    default:
+                        retval = destination_->key(value, context, ec);
+                        break;
+                }
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (!level_stack_.back().is_object() && level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.push_back('\"');
+                        key_buffer_.insert(key_buffer_.end(), value.begin(), value.end());
+                        key_buffer_.push_back('\"');
+                        retval = true;
+                        break;
+                    default:
+                        retval = destination_->string_value(value, tag, context, ec);
+                        break;
+                }
+            }
+
+            level_stack_.back().advance();
+            return retval;
+        }
+
+        bool visit_byte_string(const byte_string_view& value, 
+                                  semantic_tag tag,
+                                  const ser_context& context,
+                                  std::error_code& ec) override
+        {
+            bool retval = true;
+
+            if (level_stack_.back().is_key() || level_stack_.back().target() == target_t::buffer)
+            {
+                key_.clear();
+                switch (tag)
+                {
+                    case semantic_tag::base64:
+                        encode_base64(value.begin(), value.end(), key_);
+                        break;
+                    case semantic_tag::base16:
+                        encode_base16(value.begin(), value.end(),key_);
+                        break;
+                    default:
+                        encode_base64url(value.begin(), value.end(),key_);
+                        break;
+                }
+            }
+
+            if (level_stack_.back().is_key())
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.push_back('\"');
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        key_buffer_.push_back('\"');
+                        key_buffer_.push_back(':');
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->key(key_, context, ec);
+                        break;
+                }
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (!level_stack_.back().is_object() && level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.push_back('\"');
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        key_buffer_.push_back('\"');
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->byte_string_value(value, tag, context, ec);
+                        break;
+                }
+            }
+
+            level_stack_.back().advance();
+            return retval;
+        }
+
+        bool visit_byte_string(const byte_string_view& value, 
+                               uint64_t ext_tag,
+                               const ser_context& context,
+                               std::error_code& ec) override
+        {
+            bool retval = true;
+
+            if (level_stack_.back().is_key() || level_stack_.back().target() == target_t::buffer)
+            {
+                key_.clear();
+                encode_base64url(value.begin(), value.end(),key_);
+            }
+
+            if (level_stack_.back().is_key())
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.push_back('\"');
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        key_buffer_.push_back('\"');
+                        key_buffer_.push_back(':');
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->key(key_, context, ec);
+                        break;
+                }
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (!level_stack_.back().is_object() && level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.push_back('\"');
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        key_buffer_.push_back('\"');
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->byte_string_value(value, ext_tag, context, ec);
+                        break;
+                }
+            }
+
+            level_stack_.back().advance();
+            return retval;
+        }
+
+        bool visit_uint64(uint64_t value, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            bool retval = true;
+
+            if (level_stack_.back().is_key() || level_stack_.back().target() == target_t::buffer)
+            {
+                key_.clear();
+                jsoncons::detail::from_integer(value,key_);
+            }
+
+            if (level_stack_.back().is_key())
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        key_buffer_.push_back(':');
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->key(key_, context, ec);
+                        break;
+                }
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (!level_stack_.back().is_object() && level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->uint64_value(value, tag, context, ec);
+                        break;
+                }
+            }
+
+            level_stack_.back().advance();
+            return retval;
+        }
+
+        bool visit_int64(int64_t value, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            bool retval = true;
+
+            if (level_stack_.back().is_key() || level_stack_.back().target() == target_t::buffer)
+            {
+                key_.clear();
+                jsoncons::detail::from_integer(value,key_);
+            }
+
+            if (level_stack_.back().is_key())
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        key_buffer_.push_back(':');
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->key(key_, context, ec);
+                        break;
+                }
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (!level_stack_.back().is_object() && level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->int64_value(value, tag, context, ec);
+                        break;
+                }
+            }
+
+            level_stack_.back().advance();
+            return retval;
+        }
+
+        bool visit_half(uint16_t value, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            bool retval = true;
+
+            if (level_stack_.back().is_key() || level_stack_.back().target() == target_t::buffer)
+            {
+                key_.clear();
+                jsoncons::string_sink<string_type> sink(key_);
+                jsoncons::detail::write_double f{float_chars_format::general,0};
+                double x = binary::decode_half(value);
+                f(x, sink);
+            }
+
+            if (level_stack_.back().is_key())
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        key_buffer_.push_back(':');
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->key(key_, context, ec);
+                        break;
+                }
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (!level_stack_.back().is_object() && level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->half_value(value, tag, context, ec);
+                        break;
+                }
+            }
+
+            level_stack_.back().advance();
+            return retval;
+        }
+
+        bool visit_double(double value, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            bool retval = true;
+
+            if (level_stack_.back().is_key() || level_stack_.back().target() == target_t::buffer)
+            {
+                key_.clear();
+                string_sink<string_type> sink(key_);
+                jsoncons::detail::write_double f{float_chars_format::general,0};
+                f(value, sink);
+            }
+
+            if (level_stack_.back().is_key())
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        key_buffer_.push_back(':');
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->key(key_, context, ec);
+                        break;
+                }
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (!level_stack_.back().is_object() && level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->double_value(value, tag, context, ec);
+                        break;
+                }
+            }
+
+            level_stack_.back().advance();
+            return retval;
+        }
+
+        bool visit_bool(bool value, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            bool retval = true;
+
+            if (level_stack_.back().is_key() || level_stack_.back().target() == target_t::buffer)
+            {
+                key_ = value ? true_constant : false_constant;
+            }
+
+            if (level_stack_.back().is_key())
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        key_buffer_.push_back(':');
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->key(key_, context, ec);
+                        break;
+                }
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (!level_stack_.back().is_object() && level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->bool_value(value, tag, context, ec);
+                        break;
+                }
+            }
+
+            level_stack_.back().advance();
+            return retval;
+        }
+
+        bool visit_null(semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            bool retval = true;
+
+            if (level_stack_.back().is_key() || level_stack_.back().target() == target_t::buffer)
+            {
+                key_ = null_constant;
+            }
+
+            if (level_stack_.back().is_key())
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        key_buffer_.push_back(':');
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->key(key_, context, ec);
+                        break;
+                }
+            }
+            else
+            {
+                switch (level_stack_.back().target())
+                {
+                    case target_t::buffer:
+                        if (!level_stack_.back().is_object() && level_stack_.back().count() > 0)
+                        {
+                            key_buffer_.push_back(',');
+                        }
+                        key_buffer_.insert(key_buffer_.end(), key_.begin(), key_.end());
+                        retval = true; 
+                        break;
+                    default:
+                        retval = destination_->null_value(tag, context, ec);
+                        break;
+                }
+            }
+
+            level_stack_.back().advance();
+            return retval;
+        }
+
+        bool visit_typed_array(const jsoncons::span<const uint8_t>& s, 
+                               semantic_tag tag,
+                               const ser_context& context, 
+                               std::error_code& ec) override 
+        {
+            bool is_key = level_stack_.back().is_key();
+            level_stack_.back().advance();
+
+            if (is_key || level_stack_.back().target() == target_t::buffer)
+            {
+                return basic_json_visitor2<CharT>::visit_typed_array(s,tag,context,ec);
+            }
+            else
+            {
+                return destination_->typed_array(s, tag, context, ec);
+            }
+        }
+
+        bool visit_typed_array(const jsoncons::span<const uint16_t>& s, 
+                                    semantic_tag tag, 
+                                    const ser_context& context, 
+                                    std::error_code& ec) override  
+        {
+            bool is_key = level_stack_.back().is_key();
+            level_stack_.back().advance();
+
+            if (is_key || level_stack_.back().target() == target_t::buffer)
+            {
+                return basic_json_visitor2<CharT>::visit_typed_array(s,tag,context,ec);
+            }
+            else
+            {
+                return destination_->typed_array(s, tag, context, ec);
+            }
+        }
+
+        bool visit_typed_array(const jsoncons::span<const uint32_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec) override 
+        {
+            bool is_key = level_stack_.back().is_key();
+            level_stack_.back().advance();
+
+            if (is_key || level_stack_.back().target() == target_t::buffer)
+            {
+                return basic_json_visitor2<CharT>::visit_typed_array(s,tag,context,ec);
+            }
+            else
+            {
+                return destination_->typed_array(s, tag, context, ec);
+            }
+        }
+
+        bool visit_typed_array(const jsoncons::span<const uint64_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec) override 
+        {
+            bool is_key = level_stack_.back().is_key();
+            level_stack_.back().advance();
+
+            if (is_key || level_stack_.back().target() == target_t::buffer)
+            {
+                return basic_json_visitor2<CharT>::visit_typed_array(s,tag,context,ec);
+            }
+            else
+            {
+                return destination_->typed_array(s, tag, context, ec);
+            }
+        }
+
+        bool visit_typed_array(const jsoncons::span<const int8_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec) override  
+        {
+            bool is_key = level_stack_.back().is_key();
+            level_stack_.back().advance();
+
+            if (is_key || level_stack_.back().target() == target_t::buffer)
+            {
+                return basic_json_visitor2<CharT>::visit_typed_array(s,tag,context,ec);
+            }
+            else
+            {
+                return destination_->typed_array(s, tag, context, ec);
+            }
+        }
+
+        bool visit_typed_array(const jsoncons::span<const int16_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec) override  
+        {
+            bool is_key = level_stack_.back().is_key();
+            level_stack_.back().advance();
+
+            if (is_key || level_stack_.back().target() == target_t::buffer)
+            {
+                return basic_json_visitor2<CharT>::visit_typed_array(s,tag,context,ec);
+            }
+            else
+            {
+                return destination_->typed_array(s, tag, context, ec);
+            }
+        }
+
+        bool visit_typed_array(const jsoncons::span<const int32_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec) override  
+        {
+            bool is_key = level_stack_.back().is_key();
+            level_stack_.back().advance();
+
+            if (is_key || level_stack_.back().target() == target_t::buffer)
+            {
+                return basic_json_visitor2<CharT>::visit_typed_array(s,tag,context,ec);
+            }
+            else
+            {
+                return destination_->typed_array(s, tag, context, ec);
+            }
+        }
+
+        bool visit_typed_array(const jsoncons::span<const int64_t>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec) override  
+        {
+            bool is_key = level_stack_.back().is_key();
+            level_stack_.back().advance();
+
+            if (is_key || level_stack_.back().target() == target_t::buffer)
+            {
+                return basic_json_visitor2<CharT>::visit_typed_array(s,tag,context,ec);
+            }
+            else
+            {
+                return destination_->typed_array(s, tag, context, ec);
+            }
+        }
+
+        bool visit_typed_array(half_arg_t, 
+                               const jsoncons::span<const uint16_t>& s, 
+                               semantic_tag tag, 
+                               const ser_context& context, 
+                               std::error_code& ec) override  
+        {
+            bool is_key = level_stack_.back().is_key();
+            level_stack_.back().advance();
+
+            if (is_key || level_stack_.back().target() == target_t::buffer)
+            {
+                return basic_json_visitor2<CharT>::visit_typed_array(half_arg,s,tag,context,ec);
+            }
+            else
+            {
+                return destination_->typed_array(half_arg, s, tag, context, ec);
+            }
+        }
+
+        bool visit_typed_array(const jsoncons::span<const float>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec) override  
+        {
+            bool is_key = level_stack_.back().is_key();
+            level_stack_.back().advance();
+
+            if (is_key || level_stack_.back().target() == target_t::buffer)
+            {
+                return basic_json_visitor2<CharT>::visit_typed_array(s,tag,context,ec);
+            }
+            else
+            {
+                return destination_->typed_array(s, tag, context, ec);
+            }
+        }
+
+        bool visit_typed_array(const jsoncons::span<const double>& s, 
+                                    semantic_tag tag,
+                                    const ser_context& context, 
+                                    std::error_code& ec) override  
+        {
+            bool is_key = level_stack_.back().is_key();
+            level_stack_.back().advance();
+
+            if (is_key || level_stack_.back().target() == target_t::buffer)
+            {
+                return basic_json_visitor2<CharT>::visit_typed_array(s,tag,context,ec);
+            }
+            else
+            {
+                return destination_->typed_array(s, tag, context, ec);
+            }
+        }
+    };
+
+    template <class CharT>
+    class basic_default_json_visitor2 : public basic_json_visitor2<CharT>
+    {
+        bool parse_more_;
+        std::error_code ec_;
+    public:
+        using typename basic_json_visitor2<CharT>::string_view_type;
+
+        basic_default_json_visitor2(bool accept_more = true,
+                                    std::error_code ec = std::error_code())
+            : parse_more_(accept_more), ec_(ec)
+        {
+        }
+    private:
+        void visit_flush() override
+        {
+        }
+
+        bool visit_begin_object(semantic_tag, const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_begin_object(std::size_t, semantic_tag, const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_end_object(const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_begin_array(semantic_tag, const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_begin_array(std::size_t, semantic_tag, const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_end_array(const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_null(semantic_tag, const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_string(const string_view_type&, semantic_tag, const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_byte_string(const byte_string_view&, semantic_tag, const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_uint64(uint64_t, semantic_tag, const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_int64(int64_t, semantic_tag, const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_half(uint16_t, semantic_tag, const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_double(double, semantic_tag, const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+
+        bool visit_bool(bool, semantic_tag, const ser_context&, std::error_code& ec) override
+        {
+            if (ec_)
+            {
+                ec = ec_;
+            }
+            return parse_more_;
+        }
+    };
+
+    // basic_json_visitor_to_visitor2_adaptor
+
+    template <class CharT>
+    class basic_json_visitor_to_visitor2_adaptor : public basic_json_visitor<CharT>
+    {
+    public:
+        using typename basic_json_visitor<CharT>::char_type;
+        using typename basic_json_visitor<CharT>::string_view_type;
+    private:
+        basic_json_visitor2<char_type>& destination_;
+
+        // noncopyable and nonmoveable
+        basic_json_visitor_to_visitor2_adaptor(const basic_json_visitor_to_visitor2_adaptor&) = delete;
+        basic_json_visitor_to_visitor2_adaptor& operator=(const basic_json_visitor_to_visitor2_adaptor&) = delete;
+    public:
+        basic_json_visitor_to_visitor2_adaptor(basic_json_visitor2<char_type>& visitor)
+            : destination_(visitor)
+        {
+        }
+
+        basic_json_visitor2<char_type>& destination()
+        {
+            return destination_;
+        }
+
+    private:
+        void visit_flush() override
+        {
+            destination_.flush();
+        }
+
+        bool visit_begin_object(semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            return destination_.begin_object(tag, context, ec);
+        }
+
+        bool visit_begin_object(std::size_t length, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            return destination_.begin_object(length, tag, context, ec);
+        }
+
+        bool visit_end_object(const ser_context& context, std::error_code& ec) override
+        {
+            return destination_.end_object(context, ec);
+        }
+
+        bool visit_begin_array(semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            return destination_.begin_array(tag, context, ec);
+        }
+
+        bool visit_begin_array(std::size_t length, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            return destination_.begin_array(length, tag, context, ec);
+        }
+
+        bool visit_end_array(const ser_context& context, std::error_code& ec) override
+        {
+            return destination_.end_array(context, ec);
+        }
+
+        bool visit_key(const string_view_type& name,
+                       const ser_context& context,
+                       std::error_code& ec) override
+        {
+            return destination_.visit_string(name, context, ec);
+        }
+
+        bool visit_string(const string_view_type& value,
+                          semantic_tag tag,
+                          const ser_context& context,
+                          std::error_code& ec) override
+        {
+            return destination_.string_value(value, tag, context, ec);
+        }
+
+        bool visit_byte_string(const byte_string_view& b, 
+                               semantic_tag tag,
+                               const ser_context& context,
+                               std::error_code& ec) override
+        {
+            return destination_.byte_string_value(b, tag, context, ec);
+        }
+
+        bool visit_uint64(uint64_t value, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            return destination_.uint64_value(value, tag, context, ec);
+        }
+
+        bool visit_int64(int64_t value, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            return destination_.int64_value(value, tag, context, ec);
+        }
+
+        bool visit_half(uint16_t value, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            return destination_.half_value(value, tag, context, ec);
+        }
+
+        bool visit_double(double value, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            return destination_.double_value(value, tag, context, ec);
+        }
+
+        bool visit_bool(bool value, semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            return destination_.bool_value(value, tag, context, ec);
+        }
+
+        bool visit_null(semantic_tag tag, const ser_context& context, std::error_code& ec) override
+        {
+            return destination_.null_value(tag, context, ec);
+        }
+    };
+
+    class diagnostics_visitor2 : public basic_default_json_visitor2<char>
+    {
+        bool visit_begin_object(semantic_tag, const ser_context&, std::error_code&) override
+        {
+            std::cout << "visit_begin_object" << std::endl; 
+            return true;
+        }
+
+        bool visit_begin_object(std::size_t length, semantic_tag, const ser_context&, std::error_code&) override
+        {
+            std::cout << "visit_begin_object " << length << std::endl; 
+            return true;
+        }
+
+        bool visit_end_object(const ser_context&, std::error_code&) override
+        {
+            std::cout << "visit_end_object" << std::endl; 
+            return true;
+        }
+
+        bool visit_begin_array(semantic_tag, const ser_context&, std::error_code&) override
+        {
+            std::cout << "visit_begin_array" << std::endl;
+            return true;
+        }
+
+        bool visit_begin_array(std::size_t length, semantic_tag, const ser_context&, std::error_code&) override
+        {
+            std::cout << "visit_begin_array " << length << std::endl; 
+            return true;
+        }
+
+        bool visit_end_array(const ser_context&, std::error_code&) override
+        {
+            std::cout << "visit_end_array" << std::endl; 
+            return true;
+        }
+
+        bool visit_string(const string_view_type& s, semantic_tag, const ser_context&, std::error_code&) override
+        {
+            std::cout << "visit_string " << s << std::endl; 
+            return true;
+        }
+        bool visit_int64(int64_t val, semantic_tag, const ser_context&, std::error_code&) override
+        {
+            std::cout << "visit_int64 " << val << std::endl; 
+            return true;
+        }
+        bool visit_uint64(uint64_t val, semantic_tag, const ser_context&, std::error_code&) override
+        {
+            std::cout << "visit_uint64 " << val << std::endl; 
+            return true;
+        }
+        bool visit_bool(bool val, semantic_tag, const ser_context&, std::error_code&) override
+        {
+            std::cout << "visit_bool " << val << std::endl; 
+            return true;
+        }
+        bool visit_null(semantic_tag, const ser_context&, std::error_code&) override
+        {
+            std::cout << "visit_null " << std::endl; 
+            return true;
+        }
+
+        bool visit_typed_array(const jsoncons::span<const uint16_t>& s, 
+                                    semantic_tag tag, 
+                                    const ser_context&, 
+                                    std::error_code&) override  
+        {
+            std::cout << "visit_typed_array uint16_t " << tag << std::endl; 
+            for (auto val : s)
+            {
+                std::cout << val << "" << std::endl;
+            }
+            std::cout << "" << std::endl;
+            return true;
+        }
+
+        bool visit_typed_array(half_arg_t, const jsoncons::span<const uint16_t>& s,
+            semantic_tag tag,
+            const ser_context&,
+            std::error_code&) override
+        {
+            std::cout << "visit_typed_array half_arg_t uint16_t " << tag << "" << std::endl;
+            for (auto val : s)
+            {
+                std::cout << val << "" << std::endl;
+            }
+            std::cout << "" << std::endl;
+            return true;
+        }
+    };
+
+    using json_visitor2 = basic_json_visitor2<char>;
+    using default_json_visitor2 = basic_default_json_visitor2<char>;
+    using json_visitor2_to_visitor_adaptor = basic_json_visitor2_to_visitor_adaptor<char>;
+
+} // namespace jsoncons
+
+#endif