From 1d055261b4144dbf86b2658437015b15d4dd9bff Mon Sep 17 00:00:00 2001
From: Richard <q@1bpm.net>
Date: Sun, 4 Sep 2022 00:32:56 +0100
Subject: initial

---
 include/jsoncons_ext/ubjson/ubjson_parser.hpp | 880 ++++++++++++++++++++++++++
 1 file changed, 880 insertions(+)
 create mode 100644 include/jsoncons_ext/ubjson/ubjson_parser.hpp

(limited to 'include/jsoncons_ext/ubjson/ubjson_parser.hpp')

diff --git a/include/jsoncons_ext/ubjson/ubjson_parser.hpp b/include/jsoncons_ext/ubjson/ubjson_parser.hpp
new file mode 100644
index 0000000..468f139
--- /dev/null
+++ b/include/jsoncons_ext/ubjson/ubjson_parser.hpp
@@ -0,0 +1,880 @@
+// Copyright 2017 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_UBJSON_UBJSON_PARSER_HPP
+#define JSONCONS_UBJSON_UBJSON_PARSER_HPP
+
+#include <string>
+#include <memory>
+#include <utility> // std::move
+#include <jsoncons/json.hpp>
+#include <jsoncons/source.hpp>
+#include <jsoncons/json_visitor.hpp>
+#include <jsoncons/config/jsoncons_config.hpp>
+#include <jsoncons_ext/ubjson/ubjson_type.hpp>
+#include <jsoncons_ext/ubjson/ubjson_error.hpp>
+#include <jsoncons_ext/ubjson/ubjson_options.hpp>
+
+namespace jsoncons { namespace ubjson {
+
+enum class parse_mode {root,accept,array,indefinite_array,strongly_typed_array,map_key,map_value,strongly_typed_map_key,strongly_typed_map_value,indefinite_map_key,indefinite_map_value};
+
+struct parse_state 
+{
+    parse_mode mode; 
+    std::size_t length;
+    uint8_t type;
+    std::size_t index;
+
+    parse_state(parse_mode mode, std::size_t length, uint8_t type = 0) noexcept
+        : mode(mode), length(length), type(type), index(0)
+    {
+    }
+
+    parse_state(const parse_state&) = default;
+    parse_state(parse_state&&) = default;
+};
+
+template <class Source,class Allocator=std::allocator<char>>
+class basic_ubjson_parser : public ser_context
+{
+    using char_type = char;
+    using char_traits_type = std::char_traits<char>;
+    using temp_allocator_type = Allocator;
+    using char_allocator_type = typename std::allocator_traits<temp_allocator_type>:: template rebind_alloc<char_type>;                  
+    using byte_allocator_type = typename std::allocator_traits<temp_allocator_type>:: template rebind_alloc<uint8_t>;                  
+    using parse_state_allocator_type = typename std::allocator_traits<temp_allocator_type>:: template rebind_alloc<parse_state>;                         
+
+    Source source_;
+    ubjson_decode_options options_;
+    bool more_;
+    bool done_;
+    std::basic_string<char,std::char_traits<char>,char_allocator_type> text_buffer_;
+    std::vector<parse_state,parse_state_allocator_type> state_stack_;
+    int nesting_depth_;
+public:
+    template <class Sourceable>
+        basic_ubjson_parser(Sourceable&& source,
+                          const ubjson_decode_options& options = ubjson_decode_options(),
+                          const Allocator alloc = Allocator())
+       : source_(std::forward<Sourceable>(source)), 
+         options_(options),
+         more_(true), 
+         done_(false),
+         text_buffer_(alloc),
+         state_stack_(alloc),
+         nesting_depth_(0)
+    {
+        state_stack_.emplace_back(parse_mode::root,0);
+    }
+
+    void restart()
+    {
+        more_ = true;
+    }
+
+    void reset()
+    {
+        more_ = true;
+        done_ = false;
+        text_buffer_.clear();
+        state_stack_.clear();
+        state_stack_.emplace_back(parse_mode::root,0,0);
+        nesting_depth_ = 0;
+    }
+
+    template <class Sourceable>
+    void reset(Sourceable&& source)
+    {
+        source_ = std::forward<Sourceable>(source);
+        reset();
+    }
+
+    bool done() const
+    {
+        return done_;
+    }
+
+    bool stopped() const
+    {
+        return !more_;
+    }
+
+    std::size_t line() const override
+    {
+        return 0;
+    }
+
+    std::size_t column() const override
+    {
+        return source_.position();
+    }
+
+    void parse(json_visitor& visitor, std::error_code& ec)
+    {
+        while (!done_ && more_)
+        {
+            switch (state_stack_.back().mode)
+            {
+                case parse_mode::array:
+                {
+                    if (state_stack_.back().index < state_stack_.back().length)
+                    {
+                        ++state_stack_.back().index;
+                        read_type_and_value(visitor, ec);
+                        if (ec)
+                        {
+                            return;
+                        }
+                    }
+                    else
+                    {
+                        end_array(visitor, ec);
+                    }
+                    break;
+                }
+                case parse_mode::strongly_typed_array:
+                {
+                    if (state_stack_.back().index < state_stack_.back().length)
+                    {
+                        ++state_stack_.back().index;
+                        read_value(visitor, state_stack_.back().type, ec);
+                        if (ec)
+                        {
+                            return;
+                        }
+                    }
+                    else
+                    {
+                        end_array(visitor, ec);
+                    }
+                    break;
+                }
+                case parse_mode::indefinite_array:
+                {
+                    auto c = source_.peek();
+                    if (c.eof)
+                    {
+                        ec = ubjson_errc::unexpected_eof;
+                        more_ = false;
+                        return;
+                    }
+                    if (c.value == jsoncons::ubjson::ubjson_type::end_array_marker)
+                    {
+                        source_.ignore(1);
+                        end_array(visitor, ec);
+                        if (ec)
+                        {
+                            return;
+                        }
+                    }
+                    else
+                    {
+                        if (++state_stack_.back().index > options_.max_items())
+                        {
+                            ec = ubjson_errc::max_items_exceeded;
+                            more_ = false;
+                            return;
+                        }
+                        read_type_and_value(visitor, ec);
+                        if (ec)
+                        {
+                            return;
+                        }
+                    }
+                    break;
+                }
+                case parse_mode::map_key:
+                {
+                    if (state_stack_.back().index < state_stack_.back().length)
+                    {
+                        ++state_stack_.back().index;
+                        read_key(visitor, ec);
+                        if (ec)
+                        {
+                            return;
+                        }
+                        state_stack_.back().mode = parse_mode::map_value;
+                    }
+                    else
+                    {
+                        end_object(visitor, ec);
+                    }
+                    break;
+                }
+                case parse_mode::map_value:
+                {
+                    state_stack_.back().mode = parse_mode::map_key;
+                    read_type_and_value(visitor, ec);
+                    if (ec)
+                    {
+                        return;
+                    }
+                    break;
+                }
+                case parse_mode::strongly_typed_map_key:
+                {
+                    if (state_stack_.back().index < state_stack_.back().length)
+                    {
+                        ++state_stack_.back().index;
+                        read_key(visitor, ec);
+                        if (ec)
+                        {
+                            return;
+                        }
+                        state_stack_.back().mode = parse_mode::strongly_typed_map_value;
+                    }
+                    else
+                    {
+                        end_object(visitor, ec);
+                    }
+                    break;
+                }
+                case parse_mode::strongly_typed_map_value:
+                {
+                    state_stack_.back().mode = parse_mode::strongly_typed_map_key;
+                    read_value(visitor, state_stack_.back().type, ec);
+                    if (ec)
+                    {
+                        return;
+                    }
+                    break;
+                }
+                case parse_mode::indefinite_map_key:
+                {
+                    auto c = source_.peek();
+                    if (c.eof)
+                    {
+                        ec = ubjson_errc::unexpected_eof;
+                        more_ = false;
+                        return;
+                    }
+                    if (c.value == jsoncons::ubjson::ubjson_type::end_object_marker)
+                    {
+                        source_.ignore(1);
+                        end_object(visitor, ec);
+                        if (ec)
+                        {
+                            return;
+                        }
+                    }
+                    else
+                    {
+                        if (++state_stack_.back().index > options_.max_items())
+                        {
+                            ec = ubjson_errc::max_items_exceeded;
+                            more_ = false;
+                            return;
+                        }
+                        read_key(visitor, ec);
+                        if (ec)
+                        {
+                            return;
+                        }
+                        state_stack_.back().mode = parse_mode::indefinite_map_value;
+                    }
+                    break;
+                }
+                case parse_mode::indefinite_map_value:
+                {
+                    state_stack_.back().mode = parse_mode::indefinite_map_key;
+                    read_type_and_value(visitor, ec);
+                    if (ec)
+                    {
+                        return;
+                    }
+                    break;
+                }
+                case parse_mode::root:
+                {
+                    state_stack_.back().mode = parse_mode::accept;
+                    read_type_and_value(visitor, ec);
+                    if (ec)
+                    {
+                        return;
+                    }
+                    break;
+                }
+                case parse_mode::accept:
+                {
+                    JSONCONS_ASSERT(state_stack_.size() == 1);
+                    state_stack_.clear();
+                    more_ = false;
+                    done_ = true;
+                    visitor.flush();
+                    break;
+                }
+            }
+        }
+    }
+private:
+    void read_type_and_value(json_visitor& visitor, std::error_code& ec)
+    {
+        if (source_.is_error())
+        {
+            ec = ubjson_errc::source_error;
+            more_ = false;
+            return;
+        }   
+
+        uint8_t b;
+        if (source_.read(&b, 1) == 0)
+        {
+            ec = ubjson_errc::unexpected_eof;
+            more_ = false;
+            return;
+        }
+        read_value(visitor, b, ec);
+    }
+
+    void read_value(json_visitor& visitor, uint8_t type, std::error_code& ec)
+    {
+        switch (type)
+        {
+            case jsoncons::ubjson::ubjson_type::null_type: 
+            {
+                more_ = visitor.null_value(semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::no_op_type: 
+            {
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::true_type:
+            {
+                more_ = visitor.bool_value(true, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::false_type:
+            {
+                more_ = visitor.bool_value(false, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::int8_type: 
+            {
+                uint8_t buf[sizeof(int8_t)];
+                if (source_.read(buf, sizeof(int8_t)) != sizeof(int8_t))
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                int8_t val = binary::big_to_native<int8_t>(buf, sizeof(buf));
+                more_ = visitor.int64_value(val, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::uint8_type: 
+            {
+                uint8_t b;
+                if (source_.read(&b, 1) == 0)
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                more_ = visitor.uint64_value(b, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::int16_type: 
+            {
+                uint8_t buf[sizeof(int16_t)];
+                if (source_.read(buf, sizeof(int16_t)) != sizeof(int16_t))
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                int16_t val = binary::big_to_native<int16_t>(buf, sizeof(buf));
+                more_ = visitor.int64_value(val, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::int32_type: 
+            {
+                uint8_t buf[sizeof(int32_t)];
+                if (source_.read(buf, sizeof(int32_t)) != sizeof(int32_t))
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                int32_t val = binary::big_to_native<int32_t>(buf, sizeof(buf));
+                more_ = visitor.int64_value(val, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::int64_type: 
+            {
+                uint8_t buf[sizeof(int64_t)];
+                if (source_.read(buf, sizeof(int64_t)) != sizeof(int64_t))
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                int64_t val = binary::big_to_native<int64_t>(buf, sizeof(buf));
+                more_ = visitor.int64_value(val, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::float32_type: 
+            {
+                uint8_t buf[sizeof(float)];
+                if (source_.read(buf, sizeof(float)) != sizeof(float))
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                float val = binary::big_to_native<float>(buf, sizeof(buf));
+                more_ = visitor.double_value(val, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::float64_type: 
+            {
+                uint8_t buf[sizeof(double)];
+                if (source_.read(buf, sizeof(double)) != sizeof(double))
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                double val = binary::big_to_native<double>(buf, sizeof(buf));
+                more_ = visitor.double_value(val, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::char_type: 
+            {
+                text_buffer_.clear();
+                if (source_reader<Source>::read(source_,text_buffer_,1) != 1)
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                auto result = unicode_traits::validate(text_buffer_.data(),text_buffer_.size());
+                if (result.ec != unicode_traits::conv_errc())
+                {
+                    ec = ubjson_errc::invalid_utf8_text_string;
+                    more_ = false;
+                    return;
+                }
+                more_ = visitor.string_value(text_buffer_, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::string_type: 
+            {
+                std::size_t length = get_length(ec);
+                if (ec)
+                {
+                    return;
+                }
+                text_buffer_.clear();
+                if (source_reader<Source>::read(source_,text_buffer_,length) != length)
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                auto result = unicode_traits::validate(text_buffer_.data(),text_buffer_.size());
+                if (result.ec != unicode_traits::conv_errc())
+                {
+                    ec = ubjson_errc::invalid_utf8_text_string;
+                    more_ = false;
+                    return;
+                }
+                more_ = visitor.string_value(jsoncons::basic_string_view<char>(text_buffer_.data(),text_buffer_.length()), semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::high_precision_number_type: 
+            {
+                std::size_t length = get_length(ec);
+                if (ec)
+                {
+                    return;
+                }
+                text_buffer_.clear();
+                if (source_reader<Source>::read(source_,text_buffer_,length) != length)
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                if (jsoncons::detail::is_base10(text_buffer_.data(),text_buffer_.length()))
+                {
+                    more_ = visitor.string_value(jsoncons::basic_string_view<char>(text_buffer_.data(),text_buffer_.length()), semantic_tag::bigint, *this, ec);
+                }
+                else
+                {
+                    more_ = visitor.string_value(jsoncons::basic_string_view<char>(text_buffer_.data(),text_buffer_.length()), semantic_tag::bigdec, *this, ec);
+                }
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::start_array_marker: 
+            {
+                begin_array(visitor,ec);
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::start_object_marker: 
+            {
+                begin_object(visitor, ec);
+                break;
+            }
+            default:
+            {
+                ec = ubjson_errc::unknown_type;
+                break;
+            }
+        }
+        if (ec)
+        {
+            more_ = false;
+        }
+    }
+
+    void begin_array(json_visitor& visitor, std::error_code& ec)
+    {
+        if (JSONCONS_UNLIKELY(++nesting_depth_ > options_.max_nesting_depth()))
+        {
+            ec = ubjson_errc::max_nesting_depth_exceeded;
+            more_ = false;
+            return;
+        } 
+
+        auto c = source_.peek();
+        if (c.eof)
+        {
+            ec = ubjson_errc::unexpected_eof;
+            more_ = false;
+            return;
+        }
+        if (c.value == jsoncons::ubjson::ubjson_type::type_marker)
+        {
+            source_.ignore(1);
+            uint8_t b;
+            if (source_.read(&b, 1) == 0)
+            {
+                ec = ubjson_errc::unexpected_eof;
+                more_ = false;
+                return;
+            }
+            c = source_.peek();
+            if (c.eof)
+            {
+                ec = ubjson_errc::unexpected_eof;
+                more_ = false;
+                return;
+            }
+            if (c.value == jsoncons::ubjson::ubjson_type::count_marker)
+            {
+                source_.ignore(1);
+                std::size_t length = get_length(ec);
+                if (ec)
+                {
+                    return;
+                }
+                if (length > options_.max_items())
+                {
+                    ec = ubjson_errc::max_items_exceeded;
+                    more_ = false;
+                    return;
+                }
+                state_stack_.emplace_back(parse_mode::strongly_typed_array,length,b);
+                more_ = visitor.begin_array(length, semantic_tag::none, *this, ec);
+            }
+            else
+            {
+                ec = ubjson_errc::count_required_after_type;
+                more_ = false;
+                return;
+            }
+        }
+        else if (c.value == jsoncons::ubjson::ubjson_type::count_marker)
+        {
+            source_.ignore(1);
+            std::size_t length = get_length(ec);
+            if (ec)
+            {
+                return;
+            }
+            if (length > options_.max_items())
+            {
+                ec = ubjson_errc::max_items_exceeded;
+                more_ = false;
+                return;
+            }
+            state_stack_.emplace_back(parse_mode::array,length);
+            more_ = visitor.begin_array(length, semantic_tag::none, *this, ec);
+        }
+        else
+        {
+            state_stack_.emplace_back(parse_mode::indefinite_array,0);
+            more_ = visitor.begin_array(semantic_tag::none, *this, ec);
+        }
+    }
+
+    void end_array(json_visitor& visitor, std::error_code& ec)
+    {
+        --nesting_depth_;
+
+        more_ = visitor.end_array(*this, ec);
+        state_stack_.pop_back();
+    }
+
+    void begin_object(json_visitor& visitor, std::error_code& ec)
+    {
+        if (JSONCONS_UNLIKELY(++nesting_depth_ > options_.max_nesting_depth()))
+        {
+            ec = ubjson_errc::max_nesting_depth_exceeded;
+            more_ = false;
+            return;
+        } 
+
+        auto c = source_.peek();
+        if (c.eof)
+        {
+            ec = ubjson_errc::unexpected_eof;
+            more_ = false;
+            return;
+        }
+        if (c.value == jsoncons::ubjson::ubjson_type::type_marker)
+        {
+            source_.ignore(1);
+            uint8_t b;
+            if (source_.read(&b, 1) == 0)
+            {
+                ec = ubjson_errc::unexpected_eof;
+                more_ = false;
+                return;
+            }
+            c = source_.peek();
+            if (c.eof)
+            {
+                ec = ubjson_errc::unexpected_eof;
+                more_ = false;
+                return;
+            }
+            if (c.value == jsoncons::ubjson::ubjson_type::count_marker)
+            {
+                source_.ignore(1);
+                std::size_t length = get_length(ec);
+                if (ec)
+                {
+                    return;
+                }
+                if (length > options_.max_items())
+                {
+                    ec = ubjson_errc::max_items_exceeded;
+                    more_ = false;
+                    return;
+                }
+                state_stack_.emplace_back(parse_mode::strongly_typed_map_key,length,b);
+                more_ = visitor.begin_object(length, semantic_tag::none, *this, ec);
+            }
+            else
+            {
+                ec = ubjson_errc::count_required_after_type;
+                more_ = false;
+                return;
+            }
+        }
+        else
+        {
+            c = source_.peek();
+            if (c.eof)
+            {
+                ec = ubjson_errc::unexpected_eof;
+                more_ = false;
+                return;
+            }
+            if (c.value == jsoncons::ubjson::ubjson_type::count_marker)
+            {
+                source_.ignore(1);
+                std::size_t length = get_length(ec);
+                if (ec)
+                {
+                    return;
+                }
+                if (length > options_.max_items())
+                {
+                    ec = ubjson_errc::max_items_exceeded;
+                    more_ = false;
+                    return;
+                }
+                state_stack_.emplace_back(parse_mode::map_key,length);
+                more_ = visitor.begin_object(length, semantic_tag::none, *this, ec);
+            }
+            else
+            {
+                state_stack_.emplace_back(parse_mode::indefinite_map_key,0);
+                more_ = visitor.begin_object(semantic_tag::none, *this, ec);
+            }
+        }
+    }
+
+    void end_object(json_visitor& visitor, std::error_code& ec)
+    {
+        --nesting_depth_;
+        more_ = visitor.end_object(*this, ec);
+        state_stack_.pop_back();
+    }
+
+    std::size_t get_length(std::error_code& ec)
+    {
+        std::size_t length = 0;
+        uint8_t type;
+        if (source_.read(&type, 1) == 0)
+        {
+            ec = ubjson_errc::unexpected_eof;
+            more_ = false;
+            return length;
+        }
+        switch (type)
+        {
+            case jsoncons::ubjson::ubjson_type::int8_type: 
+            {
+                uint8_t buf[sizeof(int8_t)];
+                if (source_.read(buf, sizeof(int8_t)) != sizeof(int8_t))
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return length;
+                }
+                int8_t val = binary::big_to_native<int8_t>(buf, sizeof(buf));
+                if (val >= 0)
+                {
+                    length = val;
+                }
+                else
+                {
+                    ec = ubjson_errc::length_is_negative;
+                    more_ = false;
+                    return length;
+                }
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::uint8_type: 
+            {
+                uint8_t b;
+                if (source_.read(&b, 1) == 0)
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return length;
+                }
+                length = b;
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::int16_type: 
+            {
+                uint8_t buf[sizeof(int16_t)];
+                if (source_.read(buf, sizeof(int16_t)) != sizeof(int16_t))
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return length;
+                }
+                int16_t val = binary::big_to_native<int16_t>(buf, sizeof(buf));
+                if (val >= 0)
+                {
+                    length = val;
+                }
+                else
+                {
+                    ec = ubjson_errc::length_is_negative;
+                    more_ = false;
+                    return length;
+                }
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::int32_type: 
+            {
+                uint8_t buf[sizeof(int32_t)];
+                if (source_.read(buf, sizeof(int32_t)) != sizeof(int32_t))
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return length;
+                }
+                int32_t val = binary::big_to_native<int32_t>(buf, sizeof(buf));
+                if (val >= 0)
+                {
+                    length = static_cast<std::size_t>(val);
+                }
+                else
+                {
+                    ec = ubjson_errc::length_is_negative;
+                    more_ = false;
+                    return length;
+                }
+                break;
+            }
+            case jsoncons::ubjson::ubjson_type::int64_type: 
+            {
+                uint8_t buf[sizeof(int64_t)];
+                if (source_.read(buf, sizeof(int64_t)) != sizeof(int64_t))
+                {
+                    ec = ubjson_errc::unexpected_eof;
+                    more_ = false;
+                    return length;
+                }
+                int64_t val = binary::big_to_native<int64_t>(buf, sizeof(buf));
+                if (val >= 0)
+                {
+                    length = (std::size_t)val;
+                    if (length != (uint64_t)val)
+                    {
+                        ec = ubjson_errc::number_too_large;
+                        more_ = false;
+                        return length;
+                    }
+                }
+                else
+                {
+                    ec = ubjson_errc::length_is_negative;
+                    more_ = false;
+                    return length;
+                }
+                break;
+            }
+            default:
+            {
+                ec = ubjson_errc::length_must_be_integer;
+                more_ = false;
+                return length;
+            }
+        }
+        return length;
+    }
+
+    void read_key(json_visitor& visitor, std::error_code& ec)
+    {
+        std::size_t length = get_length(ec);
+        if (ec)
+        {
+            ec = ubjson_errc::key_expected;
+            more_ = false;
+            return;
+        }
+        text_buffer_.clear();
+        if (source_reader<Source>::read(source_,text_buffer_,length) != length)
+        {
+            ec = ubjson_errc::unexpected_eof;
+            more_ = false;
+            return;
+        }
+
+        auto result = unicode_traits::validate(text_buffer_.data(),text_buffer_.size());
+        if (result.ec != unicode_traits::conv_errc())
+        {
+            ec = ubjson_errc::invalid_utf8_text_string;
+            more_ = false;
+            return;
+        }
+        more_ = visitor.key(jsoncons::basic_string_view<char>(text_buffer_.data(),text_buffer_.length()), *this, ec);
+    }
+};
+
+}}
+
+#endif
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