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diff --git a/include/jsoncons/detail/string_wrapper.hpp b/include/jsoncons/detail/string_wrapper.hpp
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+++ b/include/jsoncons/detail/string_wrapper.hpp
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+// Copyright 2013 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_DETAIL_STRING_WRAPPER_HPP
+#define JSONCONS_DETAIL_STRING_WRAPPER_HPP
+
+#include <stdexcept>
+#include <string>
+#include <exception>
+#include <ostream>
+#include <cstring> // std::memcpy
+#include <memory> // std::allocator
+#include <jsoncons/config/compiler_support.hpp>
+
+namespace jsoncons { 
+namespace detail {
+
+    // From boost 1_71
+    template <class T, class U>
+    T launder_cast(U* u)
+    {
+    #if defined(__cpp_lib_launder) && __cpp_lib_launder >= 201606
+        return std::launder(reinterpret_cast<T>(u));
+    #elif defined(__GNUC__) &&  (__GNUC__ * 100 + __GNUC_MINOR__) > 800
+        return __builtin_launder(reinterpret_cast<T>(u));
+    #else
+        return reinterpret_cast<T>(u);
+    #endif
+    }
+
+    // string_wrapper
+
+    template <class CharT,class Allocator>
+    class string_wrapper
+    {
+    public:
+        using char_type = CharT;
+    private:
+        struct str_base_t
+        {
+            Allocator alloc_;
+        
+            Allocator& get_allocator() 
+            {
+                return alloc_;
+            }
+
+            const Allocator& get_allocator() const
+            {
+                return alloc_;
+            }
+
+            str_base_t(const Allocator& alloc)
+                : alloc_(alloc)
+            {
+            }
+
+            ~str_base_t() noexcept = default;
+        };
+
+        struct str_t : public str_base_t
+        {
+            typedef typename std::allocator_traits<Allocator>::template rebind_alloc<CharT> allocator_type;  
+            using allocator_traits_type = std::allocator_traits<allocator_type>;
+            using pointer = typename allocator_traits_type::pointer;
+
+            pointer p_;
+            std::size_t length_;
+
+            ~str_t() noexcept = default; 
+
+            const char_type* c_str() const { return type_traits::to_plain_pointer(p_); }
+            const char_type* data() const { return type_traits::to_plain_pointer(p_); }
+            std::size_t length() const { return length_; }
+        
+            str_t(const Allocator& alloc)
+                : str_base_t(alloc), p_(nullptr), length_(0)
+            {
+
+            }
+
+            str_t(const str_t&) = delete;
+            str_t& operator=(const str_t&) = delete;
+
+        };
+
+        typedef typename std::allocator_traits<Allocator>::template rebind_alloc<char> byte_allocator_type;  
+        using byte_pointer = typename std::allocator_traits<byte_allocator_type>::pointer;
+
+        typedef typename std::allocator_traits<Allocator>::template rebind_alloc<str_t> string_allocator_type;  
+        using string_pointer = typename std::allocator_traits<string_allocator_type>::pointer;
+
+        struct storage_t
+        {
+            str_t data;
+            char_type c[1];
+        };
+        typedef typename std::aligned_storage<sizeof(storage_t), alignof(storage_t)>::type json_storage_kind;
+
+        string_pointer ptr_;
+    public:
+        string_wrapper() = default;
+
+        string_wrapper(string_pointer ptr)
+            : ptr_(ptr)
+        {
+        }
+
+        string_wrapper(const char_type* data, std::size_t length, const Allocator& a) 
+        {
+            ptr_ = create(data,length,a);
+        }
+
+        string_wrapper(const string_wrapper& val) 
+        {
+            ptr_ = create(val.data(),val.length(),val.get_allocator());
+        }
+
+        string_wrapper(const string_wrapper& val, const Allocator& a) 
+        {
+            ptr_ = create(val.data(),val.length(),a);
+        }
+
+        ~string_wrapper() noexcept
+        {
+            if (ptr_ != nullptr)
+            {
+                destroy(ptr_);
+            }
+        }
+
+        void swap(string_wrapper& other) noexcept
+        {
+            std::swap(ptr_,other.ptr_);
+        }
+
+        const char_type* data() const
+        {
+            return ptr_->data();
+        }
+
+        const char_type* c_str() const
+        {
+            return ptr_->c_str();
+        }
+
+        std::size_t length() const
+        {
+            return ptr_->length();
+        }
+
+        Allocator get_allocator() const
+        {
+            return ptr_->get_allocator();
+        }
+    private:
+        static size_t aligned_size(std::size_t n)
+        {
+            return sizeof(json_storage_kind) + n;
+        }
+
+        static string_pointer create(const char_type* s, std::size_t length, const Allocator& alloc)
+        {
+            std::size_t mem_size = aligned_size(length*sizeof(char_type));
+
+            byte_allocator_type byte_alloc(alloc);
+            byte_pointer ptr = byte_alloc.allocate(mem_size);
+
+            char* storage = type_traits::to_plain_pointer(ptr);
+            str_t* ps = new(storage)str_t(byte_alloc);
+
+            auto psa = launder_cast<storage_t*>(storage); 
+
+            CharT* p = new(&psa->c)char_type[length + 1];
+            std::memcpy(p, s, length*sizeof(char_type));
+            p[length] = 0;
+            ps->p_ = std::pointer_traits<typename str_t::pointer>::pointer_to(*p);
+            ps->length_ = length;
+            return std::pointer_traits<string_pointer>::pointer_to(*ps);
+        }
+
+        static void destroy(string_pointer ptr)
+        {
+            str_t* rawp = type_traits::to_plain_pointer(ptr);
+
+            char* p = launder_cast<char*>(rawp);
+
+            std::size_t mem_size = aligned_size(ptr->length_*sizeof(char_type));
+            byte_allocator_type byte_alloc(ptr->get_allocator());
+            byte_alloc.deallocate(p,mem_size);
+        }
+    };
+
+    // tagged_string_wrapper
+
+    template <class CharT,class Allocator>
+    class tagged_string_wrapper
+    {
+    public:
+        using char_type = CharT;
+    private:
+        struct str_base_t
+        {
+            Allocator alloc_;
+
+            Allocator& get_allocator() 
+            {
+                return alloc_;
+            }
+
+            const Allocator& get_allocator() const
+            {
+                return alloc_;
+            }
+
+            str_base_t(const Allocator& alloc)
+                : alloc_(alloc)
+            {
+            }
+
+            ~str_base_t() noexcept = default;
+        };
+
+        struct str_t : public str_base_t
+        {
+            typedef typename std::allocator_traits<Allocator>::template rebind_alloc<CharT> allocator_type;  
+            using allocator_traits_type = std::allocator_traits<allocator_type>;
+            using pointer = typename allocator_traits_type::pointer;
+
+            pointer p_;
+            std::size_t length_;
+            uint64_t tag_;
+
+            ~str_t() noexcept = default; 
+
+            const char_type* c_str() const { return type_traits::to_plain_pointer(p_); }
+            const char_type* data() const { return type_traits::to_plain_pointer(p_); }
+            std::size_t length() const { return length_; }
+            uint64_t tag() const { return tag_; }
+
+            str_t(uint64_t tag, const Allocator& alloc)
+                : str_base_t(alloc), p_(nullptr), length_(0), tag_(tag)
+            {
+
+            }
+
+            str_t(const str_t&) = delete;
+            str_t& operator=(const str_t&) = delete;
+
+        };
+
+        typedef typename std::allocator_traits<Allocator>::template rebind_alloc<char> byte_allocator_type;  
+        using byte_pointer = typename std::allocator_traits<byte_allocator_type>::pointer;
+
+        typedef typename std::allocator_traits<Allocator>::template rebind_alloc<str_t> string_allocator_type;  
+        using string_pointer = typename std::allocator_traits<string_allocator_type>::pointer;
+
+        struct storage_t
+        {
+            str_t data;
+            char_type c[1];
+        };
+        typedef typename std::aligned_storage<sizeof(storage_t), alignof(storage_t)>::type json_storage_kind;
+
+        string_pointer ptr_;
+    public:
+        tagged_string_wrapper() = default;
+
+        tagged_string_wrapper(string_pointer ptr)
+            : ptr_(ptr)
+        {
+        }
+
+        tagged_string_wrapper(const char_type* data, std::size_t length, uint64_t tag, const Allocator& alloc) 
+        {
+            ptr_ = create(data, length, tag, alloc);
+        }
+
+        tagged_string_wrapper(const tagged_string_wrapper& val) 
+        {
+            ptr_ = create(val.data(), val.length(), val.tag(), val.get_allocator());
+        }
+
+        tagged_string_wrapper(const tagged_string_wrapper& val, const Allocator& alloc) 
+        {
+            ptr_ = create(val.data(), val.length(), val.tag(), alloc);
+        }
+
+        ~tagged_string_wrapper() noexcept
+        {
+            if (ptr_ != nullptr)
+            {
+                destroy(ptr_);
+            }
+        }
+
+        void swap(tagged_string_wrapper& other) noexcept
+        {
+            std::swap(ptr_,other.ptr_);
+        }
+
+        const char_type* data() const
+        {
+            return ptr_->data();
+        }
+
+        const char_type* c_str() const
+        {
+            return ptr_->c_str();
+        }
+
+        std::size_t length() const
+        {
+            return ptr_->length();
+        }
+
+        uint64_t tag() const
+        {
+            return ptr_->tag();
+        }
+
+        Allocator get_allocator() const
+        {
+            return ptr_->get_allocator();
+        }
+    private:
+        static size_t aligned_size(std::size_t n)
+        {
+            return sizeof(json_storage_kind) + n;
+        }
+
+        static string_pointer create(const char_type* s, std::size_t length, uint64_t tag, const Allocator& alloc)
+        {
+            std::size_t mem_size = aligned_size(length*sizeof(char_type));
+
+            byte_allocator_type byte_alloc(alloc);
+            byte_pointer ptr = byte_alloc.allocate(mem_size);
+
+            char* storage = type_traits::to_plain_pointer(ptr);
+            str_t* ps = new(storage)str_t(tag, byte_alloc);
+
+            auto psa = launder_cast<storage_t*>(storage); 
+
+            CharT* p = new(&psa->c)char_type[length + 1];
+            std::memcpy(p, s, length*sizeof(char_type));
+            p[length] = 0;
+            ps->p_ = std::pointer_traits<typename str_t::pointer>::pointer_to(*p);
+            ps->length_ = length;
+            return std::pointer_traits<string_pointer>::pointer_to(*ps);
+        }
+
+        static void destroy(string_pointer ptr)
+        {
+            str_t* rawp = type_traits::to_plain_pointer(ptr);
+
+            char* p = launder_cast<char*>(rawp);
+
+            std::size_t mem_size = aligned_size(ptr->length_*sizeof(char_type));
+            byte_allocator_type byte_alloc(ptr->get_allocator());
+            byte_alloc.deallocate(p,mem_size);
+        }
+    };
+
+} // namespace detail
+} // namespace jsoncons
+
+#endif