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 //     __ _____ _____ _____
 //  __|  |   __|     |   | |  JSON for Modern C++
 // |  |  |__   |  |  | | | |  version 3.12.0
 // |_____|_____|_____|_|___|  https://github.com/nlohmann/json
 //
 // SPDX-FileCopyrightText: 2013 - 2025 Niels Lohmann <https://nlohmann.me>
 // SPDX-License-Identifier: MIT
 
 #pragma once
 
 #include <cstddef>
 #include <string> // string
 #include <type_traits> // enable_if_t
 #include <utility> // move
 #include <vector> // vector
 
 #include <nlohmann/detail/exceptions.hpp>
 #include <nlohmann/detail/input/lexer.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
 #include <nlohmann/detail/string_concat.hpp>
 NLOHMANN_JSON_NAMESPACE_BEGIN
 
 /*!
 @brief SAX interface
 
 This class describes the SAX interface used by @ref nlohmann::json::sax_parse.
 Each function is called in different situations while the input is parsed. The
 boolean return value informs the parser whether to continue processing the
 input.
 */
 template<typename BasicJsonType>
 struct json_sax
 {
     using number_integer_t = typename BasicJsonType::number_integer_t;
     using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
     using number_float_t = typename BasicJsonType::number_float_t;
     using string_t = typename BasicJsonType::string_t;
     using binary_t = typename BasicJsonType::binary_t;
 
     /*!
     @brief a null value was read
     @return whether parsing should proceed
     */
     virtual bool null() = 0;
 
     /*!
     @brief a boolean value was read
     @param[in] val  boolean value
     @return whether parsing should proceed
     */
     virtual bool boolean(bool val) = 0;
 
     /*!
     @brief an integer number was read
     @param[in] val  integer value
     @return whether parsing should proceed
     */
     virtual bool number_integer(number_integer_t val) = 0;
 
     /*!
     @brief an unsigned integer number was read
     @param[in] val  unsigned integer value
     @return whether parsing should proceed
     */
     virtual bool number_unsigned(number_unsigned_t val) = 0;
 
     /*!
     @brief a floating-point number was read
     @param[in] val  floating-point value
     @param[in] s    raw token value
     @return whether parsing should proceed
     */
     virtual bool number_float(number_float_t val, const string_t& s) = 0;
 
     /*!
     @brief a string value was read
     @param[in] val  string value
     @return whether parsing should proceed
     @note It is safe to move the passed string value.
     */
     virtual bool string(string_t& val) = 0;
 
     /*!
     @brief a binary value was read
     @param[in] val  binary value
     @return whether parsing should proceed
     @note It is safe to move the passed binary value.
     */
     virtual bool binary(binary_t& val) = 0;
 
     /*!
     @brief the beginning of an object was read
     @param[in] elements  number of object elements or -1 if unknown
     @return whether parsing should proceed
     @note binary formats may report the number of elements
     */
     virtual bool start_object(std::size_t elements) = 0;
 
     /*!
     @brief an object key was read
     @param[in] val  object key
     @return whether parsing should proceed
     @note It is safe to move the passed string.
     */
     virtual bool key(string_t& val) = 0;
 
     /*!
     @brief the end of an object was read
     @return whether parsing should proceed
     */
     virtual bool end_object() = 0;
 
     /*!
     @brief the beginning of an array was read
     @param[in] elements  number of array elements or -1 if unknown
     @return whether parsing should proceed
     @note binary formats may report the number of elements
     */
     virtual bool start_array(std::size_t elements) = 0;
 
     /*!
     @brief the end of an array was read
     @return whether parsing should proceed
     */
     virtual bool end_array() = 0;
 
     /*!
     @brief a parse error occurred
     @param[in] position    the position in the input where the error occurs
     @param[in] last_token  the last read token
     @param[in] ex          an exception object describing the error
     @return whether parsing should proceed (must return false)
     */
     virtual bool parse_error(std::size_t position,
                              const std::string& last_token,
                              const detail::exception& ex) = 0;
 
     json_sax() = default;
     json_sax(const json_sax&) = default;
     json_sax(json_sax&&) noexcept = default;
     json_sax& operator=(const json_sax&) = default;
     json_sax& operator=(json_sax&&) noexcept = default;
     virtual ~json_sax() = default;
 };
 
 namespace detail
 {
 constexpr std::size_t unknown_size()
 {
     return (std::numeric_limits<std::size_t>::max)();
 }
 
 /*!
 @brief SAX implementation to create a JSON value from SAX events
 
 This class implements the @ref json_sax interface and processes the SAX events
 to create a JSON value which makes it basically a DOM parser. The structure or
 hierarchy of the JSON value is managed by the stack `ref_stack` which contains
 a pointer to the respective array or object for each recursion depth.
 
 After successful parsing, the value that is passed by reference to the
 constructor contains the parsed value.
 
 @tparam BasicJsonType  the JSON type
 */
 template<typename BasicJsonType, typename InputAdapterType>
 class json_sax_dom_parser
 {
   public:
     using number_integer_t = typename BasicJsonType::number_integer_t;
     using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
     using number_float_t = typename BasicJsonType::number_float_t;
     using string_t = typename BasicJsonType::string_t;
     using binary_t = typename BasicJsonType::binary_t;
     using lexer_t = lexer<BasicJsonType, InputAdapterType>;
 
     /*!
     @param[in,out] r  reference to a JSON value that is manipulated while
                        parsing
     @param[in] allow_exceptions_  whether parse errors yield exceptions
     */
     explicit json_sax_dom_parser(BasicJsonType& r, const bool allow_exceptions_ = true, lexer_t* lexer_ = nullptr)
         : root(r), allow_exceptions(allow_exceptions_), m_lexer_ref(lexer_)
     {}
 
     // make class move-only
     json_sax_dom_parser(const json_sax_dom_parser&) = delete;
     json_sax_dom_parser(json_sax_dom_parser&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor)
     json_sax_dom_parser& operator=(const json_sax_dom_parser&) = delete;
     json_sax_dom_parser& operator=(json_sax_dom_parser&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor)
     ~json_sax_dom_parser() = default;
 
     bool null()
     {
         handle_value(nullptr);
         return true;
     }
 
     bool boolean(bool val)
     {
         handle_value(val);
         return true;
     }
 
     bool number_integer(number_integer_t val)
     {
         handle_value(val);
         return true;
     }
 
     bool number_unsigned(number_unsigned_t val)
     {
         handle_value(val);
         return true;
     }
 
     bool number_float(number_float_t val, const string_t& /*unused*/)
     {
         handle_value(val);
         return true;
     }
 
     bool string(string_t& val)
     {
         handle_value(val);
         return true;
     }
 
     bool binary(binary_t& val)
     {
         handle_value(std::move(val));
         return true;
     }
 
     bool start_object(std::size_t len)
     {
         ref_stack.push_back(handle_value(BasicJsonType::value_t::object));
 
 #if JSON_DIAGNOSTIC_POSITIONS
         // Manually set the start position of the object here.
         // Ensure this is after the call to handle_value to ensure correct start position.
         if (m_lexer_ref)
         {
             // Lexer has read the first character of the object, so
             // subtract 1 from the position to get the correct start position.
             ref_stack.back()->start_position = m_lexer_ref->get_position() - 1;
         }
 #endif
 
         if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref_stack.back()->max_size()))
         {
             JSON_THROW(out_of_range::create(408, concat("excessive object size: ", std::to_string(len)), ref_stack.back()));
         }
 
         return true;
     }
 
     bool key(string_t& val)
     {
         JSON_ASSERT(!ref_stack.empty());
         JSON_ASSERT(ref_stack.back()->is_object());
 
         // add null at given key and store the reference for later
         object_element = &(ref_stack.back()->m_data.m_value.object->operator[](val));
         return true;
     }
 
     bool end_object()
     {
         JSON_ASSERT(!ref_stack.empty());
         JSON_ASSERT(ref_stack.back()->is_object());
 
 #if JSON_DIAGNOSTIC_POSITIONS
         if (m_lexer_ref)
         {
             // Lexer's position is past the closing brace, so set that as the end position.
             ref_stack.back()->end_position = m_lexer_ref->get_position();
         }
 #endif
 
         ref_stack.back()->set_parents();
         ref_stack.pop_back();
         return true;
     }
 
     bool start_array(std::size_t len)
     {
         ref_stack.push_back(handle_value(BasicJsonType::value_t::array));
 
 #if JSON_DIAGNOSTIC_POSITIONS
         // Manually set the start position of the array here.
         // Ensure this is after the call to handle_value to ensure correct start position.
         if (m_lexer_ref)
         {
             ref_stack.back()->start_position = m_lexer_ref->get_position() - 1;
         }
 #endif
 
         if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref_stack.back()->max_size()))
         {
             JSON_THROW(out_of_range::create(408, concat("excessive array size: ", std::to_string(len)), ref_stack.back()));
         }
 
         return true;
     }
 
     bool end_array()
     {
         JSON_ASSERT(!ref_stack.empty());
         JSON_ASSERT(ref_stack.back()->is_array());
 
 #if JSON_DIAGNOSTIC_POSITIONS
         if (m_lexer_ref)
         {
             // Lexer's position is past the closing bracket, so set that as the end position.
             ref_stack.back()->end_position = m_lexer_ref->get_position();
         }
 #endif
 
         ref_stack.back()->set_parents();
         ref_stack.pop_back();
         return true;
     }
 
     template<class Exception>
     bool parse_error(std::size_t /*unused*/, const std::string& /*unused*/,
                      const Exception& ex)
     {
         errored = true;
         static_cast<void>(ex);
         if (allow_exceptions)
         {
             JSON_THROW(ex);
         }
         return false;
     }
 
     constexpr bool is_errored() const
     {
         return errored;
     }
 
   private:
 
 #if JSON_DIAGNOSTIC_POSITIONS
     void handle_diagnostic_positions_for_json_value(BasicJsonType& v)
     {
         if (m_lexer_ref)
         {
             // Lexer has read past the current field value, so set the end position to the current position.
             // The start position will be set below based on the length of the string representation
             // of the value.
             v.end_position = m_lexer_ref->get_position();
 
             switch (v.type())
             {
                 case value_t::boolean:
                 {
                     // 4 and 5 are the string length of "true" and "false"
                     v.start_position = v.end_position - (v.m_data.m_value.boolean ? 4 : 5);
                     break;
                 }
 
                 case value_t::null:
                 {
                     // 4 is the string length of "null"
                     v.start_position = v.end_position - 4;
                     break;
                 }
 
                 case value_t::string:
                 {
                     // include the length of the quotes, which is 2
                     v.start_position = v.end_position - v.m_data.m_value.string->size() - 2;
                     break;
                 }
 
                 // As we handle the start and end positions for values created during parsing,
                 // we do not expect the following value type to be called. Regardless, set the positions
                 // in case this is created manually or through a different constructor. Exclude from lcov
                 // since the exact condition of this switch is esoteric.
                 // LCOV_EXCL_START
                 case value_t::discarded:
                 {
                     v.end_position = std::string::npos;
                     v.start_position = v.end_position;
                     break;
                 }
                 // LCOV_EXCL_STOP
                 case value_t::binary:
                 case value_t::number_integer:
                 case value_t::number_unsigned:
                 case value_t::number_float:
                 {
                     v.start_position = v.end_position - m_lexer_ref->get_string().size();
                     break;
                 }
                 case value_t::object:
                 case value_t::array:
                 {
                     // object and array are handled in start_object() and start_array() handlers
                     // skip setting the values here.
                     break;
                 }
                 default: // LCOV_EXCL_LINE
                     // Handle all possible types discretely, default handler should never be reached.
                     JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert,-warnings-as-errors) LCOV_EXCL_LINE
             }
         }
     }
 #endif
 
     /*!
     @invariant If the ref stack is empty, then the passed value will be the new
                root.
     @invariant If the ref stack contains a value, then it is an array or an
                object to which we can add elements
     */
     template<typename Value>
     JSON_HEDLEY_RETURNS_NON_NULL
     BasicJsonType* handle_value(Value&& v)
     {
         if (ref_stack.empty())
         {
             root = BasicJsonType(std::forward<Value>(v));
 
 #if JSON_DIAGNOSTIC_POSITIONS
             handle_diagnostic_positions_for_json_value(root);
 #endif
 
             return &root;
         }
 
         JSON_ASSERT(ref_stack.back()->is_array() || ref_stack.back()->is_object());
 
         if (ref_stack.back()->is_array())
         {
             ref_stack.back()->m_data.m_value.array->emplace_back(std::forward<Value>(v));
 
 #if JSON_DIAGNOSTIC_POSITIONS
             handle_diagnostic_positions_for_json_value(ref_stack.back()->m_data.m_value.array->back());
 #endif
 
             return &(ref_stack.back()->m_data.m_value.array->back());
         }
 
         JSON_ASSERT(ref_stack.back()->is_object());
         JSON_ASSERT(object_element);
         *object_element = BasicJsonType(std::forward<Value>(v));
 
 #if JSON_DIAGNOSTIC_POSITIONS
         handle_diagnostic_positions_for_json_value(*object_element);
 #endif
 
         return object_element;
     }
 
     /// the parsed JSON value
     BasicJsonType& root;
     /// stack to model hierarchy of values
     std::vector<BasicJsonType*> ref_stack {};
     /// helper to hold the reference for the next object element
     BasicJsonType* object_element = nullptr;
     /// whether a syntax error occurred
     bool errored = false;
     /// whether to throw exceptions in case of errors
     const bool allow_exceptions = true;
     /// the lexer reference to obtain the current position
     lexer_t* m_lexer_ref = nullptr;
 };
 
 template<typename BasicJsonType, typename InputAdapterType>
 class json_sax_dom_callback_parser
 {
   public:
     using number_integer_t = typename BasicJsonType::number_integer_t;
     using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
     using number_float_t = typename BasicJsonType::number_float_t;
     using string_t = typename BasicJsonType::string_t;
     using binary_t = typename BasicJsonType::binary_t;
     using parser_callback_t = typename BasicJsonType::parser_callback_t;
     using parse_event_t = typename BasicJsonType::parse_event_t;
     using lexer_t = lexer<BasicJsonType, InputAdapterType>;
 
     json_sax_dom_callback_parser(BasicJsonType& r,
                                  parser_callback_t cb,
                                  const bool allow_exceptions_ = true,
                                  lexer_t* lexer_ = nullptr)
         : root(r), callback(std::move(cb)), allow_exceptions(allow_exceptions_), m_lexer_ref(lexer_)
     {
         keep_stack.push_back(true);
     }
 
     // make class move-only
     json_sax_dom_callback_parser(const json_sax_dom_callback_parser&) = delete;
     json_sax_dom_callback_parser(json_sax_dom_callback_parser&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor)
     json_sax_dom_callback_parser& operator=(const json_sax_dom_callback_parser&) = delete;
     json_sax_dom_callback_parser& operator=(json_sax_dom_callback_parser&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor)
     ~json_sax_dom_callback_parser() = default;
 
     bool null()
     {
         handle_value(nullptr);
         return true;
     }
 
     bool boolean(bool val)
     {
         handle_value(val);
         return true;
     }
 
     bool number_integer(number_integer_t val)
     {
         handle_value(val);
         return true;
     }
 
     bool number_unsigned(number_unsigned_t val)
     {
         handle_value(val);
         return true;
     }
 
     bool number_float(number_float_t val, const string_t& /*unused*/)
     {
         handle_value(val);
         return true;
     }
 
     bool string(string_t& val)
     {
         handle_value(val);
         return true;
     }
 
     bool binary(binary_t& val)
     {
         handle_value(std::move(val));
         return true;
     }
 
     bool start_object(std::size_t len)
     {
         // check callback for object start
         const bool keep = callback(static_cast<int>(ref_stack.size()), parse_event_t::object_start, discarded);
         keep_stack.push_back(keep);
 
         auto val = handle_value(BasicJsonType::value_t::object, true);
         ref_stack.push_back(val.second);
 
         if (ref_stack.back())
         {
 
 #if JSON_DIAGNOSTIC_POSITIONS
             // Manually set the start position of the object here.
             // Ensure this is after the call to handle_value to ensure correct start position.
             if (m_lexer_ref)
             {
                 // Lexer has read the first character of the object, so
                 // subtract 1 from the position to get the correct start position.
                 ref_stack.back()->start_position = m_lexer_ref->get_position() - 1;
             }
 #endif
 
             // check object limit
             if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref_stack.back()->max_size()))
             {
                 JSON_THROW(out_of_range::create(408, concat("excessive object size: ", std::to_string(len)), ref_stack.back()));
             }
         }
         return true;
     }
 
     bool key(string_t& val)
     {
         BasicJsonType k = BasicJsonType(val);
 
         // check callback for key
         const bool keep = callback(static_cast<int>(ref_stack.size()), parse_event_t::key, k);
         key_keep_stack.push_back(keep);
 
         // add discarded value at given key and store the reference for later
         if (keep && ref_stack.back())
         {
             object_element = &(ref_stack.back()->m_data.m_value.object->operator[](val) = discarded);
         }
 
         return true;
     }
 
     bool end_object()
     {
         if (ref_stack.back())
         {
             if (!callback(static_cast<int>(ref_stack.size()) - 1, parse_event_t::object_end, *ref_stack.back()))
             {
                 // discard object
                 *ref_stack.back() = discarded;
 
 #if JSON_DIAGNOSTIC_POSITIONS
                 // Set start/end positions for discarded object.
                 handle_diagnostic_positions_for_json_value(*ref_stack.back());
 #endif
             }
             else
             {
 
 #if JSON_DIAGNOSTIC_POSITIONS
                 if (m_lexer_ref)
                 {
                     // Lexer's position is past the closing brace, so set that as the end position.
                     ref_stack.back()->end_position = m_lexer_ref->get_position();
                 }
 #endif
 
                 ref_stack.back()->set_parents();
             }
         }
 
         JSON_ASSERT(!ref_stack.empty());
         JSON_ASSERT(!keep_stack.empty());
         ref_stack.pop_back();
         keep_stack.pop_back();
 
         if (!ref_stack.empty() && ref_stack.back() && ref_stack.back()->is_structured())
         {
             // remove discarded value
             for (auto it = ref_stack.back()->begin(); it != ref_stack.back()->end(); ++it)
             {
                 if (it->is_discarded())
                 {
                     ref_stack.back()->erase(it);
                     break;
                 }
             }
         }
 
         return true;
     }
 
     bool start_array(std::size_t len)
     {
         const bool keep = callback(static_cast<int>(ref_stack.size()), parse_event_t::array_start, discarded);
         keep_stack.push_back(keep);
 
         auto val = handle_value(BasicJsonType::value_t::array, true);
         ref_stack.push_back(val.second);
 
         if (ref_stack.back())
         {
 
 #if JSON_DIAGNOSTIC_POSITIONS
             // Manually set the start position of the array here.
             // Ensure this is after the call to handle_value to ensure correct start position.
             if (m_lexer_ref)
             {
                 // Lexer has read the first character of the array, so
                 // subtract 1 from the position to get the correct start position.
                 ref_stack.back()->start_position = m_lexer_ref->get_position() - 1;
             }
 #endif
 
             // check array limit
             if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref_stack.back()->max_size()))
             {
                 JSON_THROW(out_of_range::create(408, concat("excessive array size: ", std::to_string(len)), ref_stack.back()));
             }
         }
 
         return true;
     }
 
     bool end_array()
     {
         bool keep = true;
 
         if (ref_stack.back())
         {
             keep = callback(static_cast<int>(ref_stack.size()) - 1, parse_event_t::array_end, *ref_stack.back());
             if (keep)
             {
 
 #if JSON_DIAGNOSTIC_POSITIONS
                 if (m_lexer_ref)
                 {
                     // Lexer's position is past the closing bracket, so set that as the end position.
                     ref_stack.back()->end_position = m_lexer_ref->get_position();
                 }
 #endif
 
                 ref_stack.back()->set_parents();
             }
             else
             {
                 // discard array
                 *ref_stack.back() = discarded;
 
 #if JSON_DIAGNOSTIC_POSITIONS
                 // Set start/end positions for discarded array.
                 handle_diagnostic_positions_for_json_value(*ref_stack.back());
 #endif
             }
         }
 
         JSON_ASSERT(!ref_stack.empty());
         JSON_ASSERT(!keep_stack.empty());
         ref_stack.pop_back();
         keep_stack.pop_back();
 
         // remove discarded value
         if (!keep && !ref_stack.empty() && ref_stack.back()->is_array())
         {
             ref_stack.back()->m_data.m_value.array->pop_back();
         }
 
         return true;
     }
 
     template<class Exception>
     bool parse_error(std::size_t /*unused*/, const std::string& /*unused*/,
                      const Exception& ex)
     {
         errored = true;
         static_cast<void>(ex);
         if (allow_exceptions)
         {
             JSON_THROW(ex);
         }
         return false;
     }
 
     constexpr bool is_errored() const
     {
         return errored;
     }
 
   private:
 
 #if JSON_DIAGNOSTIC_POSITIONS
     void handle_diagnostic_positions_for_json_value(BasicJsonType& v)
     {
         if (m_lexer_ref)
         {
             // Lexer has read past the current field value, so set the end position to the current position.
             // The start position will be set below based on the length of the string representation
             // of the value.
             v.end_position = m_lexer_ref->get_position();
 
             switch (v.type())
             {
                 case value_t::boolean:
                 {
                     // 4 and 5 are the string length of "true" and "false"
                     v.start_position = v.end_position - (v.m_data.m_value.boolean ? 4 : 5);
                     break;
                 }
 
                 case value_t::null:
                 {
                     // 4 is the string length of "null"
                     v.start_position = v.end_position - 4;
                     break;
                 }
 
                 case value_t::string:
                 {
                     // include the length of the quotes, which is 2
                     v.start_position = v.end_position - v.m_data.m_value.string->size() - 2;
                     break;
                 }
 
                 case value_t::discarded:
                 {
                     v.end_position = std::string::npos;
                     v.start_position = v.end_position;
                     break;
                 }
 
                 case value_t::binary:
                 case value_t::number_integer:
                 case value_t::number_unsigned:
                 case value_t::number_float:
                 {
                     v.start_position = v.end_position - m_lexer_ref->get_string().size();
                     break;
                 }
 
                 case value_t::object:
                 case value_t::array:
                 {
                     // object and array are handled in start_object() and start_array() handlers
                     // skip setting the values here.
                     break;
                 }
                 default: // LCOV_EXCL_LINE
                     // Handle all possible types discretely, default handler should never be reached.
                     JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert,-warnings-as-errors) LCOV_EXCL_LINE
             }
         }
     }
 #endif
 
     /*!
     @param[in] v  value to add to the JSON value we build during parsing
     @param[in] skip_callback  whether we should skip calling the callback
                function; this is required after start_array() and
                start_object() SAX events, because otherwise we would call the
                callback function with an empty array or object, respectively.
 
     @invariant If the ref stack is empty, then the passed value will be the new
                root.
     @invariant If the ref stack contains a value, then it is an array or an
                object to which we can add elements
 
     @return pair of boolean (whether value should be kept) and pointer (to the
             passed value in the ref_stack hierarchy; nullptr if not kept)
     */
     template<typename Value>
     std::pair<bool, BasicJsonType*> handle_value(Value&& v, const bool skip_callback = false)
     {
         JSON_ASSERT(!keep_stack.empty());
 
         // do not handle this value if we know it would be added to a discarded
         // container
         if (!keep_stack.back())
         {
             return {false, nullptr};
         }
 
         // create value
         auto value = BasicJsonType(std::forward<Value>(v));
 
 #if JSON_DIAGNOSTIC_POSITIONS
         handle_diagnostic_positions_for_json_value(value);
 #endif
 
         // check callback
         const bool keep = skip_callback || callback(static_cast<int>(ref_stack.size()), parse_event_t::value, value);
 
         // do not handle this value if we just learnt it shall be discarded
         if (!keep)
         {
             return {false, nullptr};
         }
 
         if (ref_stack.empty())
         {
             root = std::move(value);
             return {true, & root};
         }
 
         // skip this value if we already decided to skip the parent
         // (https://github.com/nlohmann/json/issues/971#issuecomment-413678360)
         if (!ref_stack.back())
         {
             return {false, nullptr};
         }
 
         // we now only expect arrays and objects
         JSON_ASSERT(ref_stack.back()->is_array() || ref_stack.back()->is_object());
 
         // array
         if (ref_stack.back()->is_array())
         {
             ref_stack.back()->m_data.m_value.array->emplace_back(std::move(value));
             return {true, & (ref_stack.back()->m_data.m_value.array->back())};
         }
 
         // object
         JSON_ASSERT(ref_stack.back()->is_object());
         // check if we should store an element for the current key
         JSON_ASSERT(!key_keep_stack.empty());
         const bool store_element = key_keep_stack.back();
         key_keep_stack.pop_back();
 
         if (!store_element)
         {
             return {false, nullptr};
         }
 
         JSON_ASSERT(object_element);
         *object_element = std::move(value);
         return {true, object_element};
     }
 
     /// the parsed JSON value
     BasicJsonType& root;
     /// stack to model hierarchy of values
     std::vector<BasicJsonType*> ref_stack {};
     /// stack to manage which values to keep
     std::vector<bool> keep_stack {}; // NOLINT(readability-redundant-member-init)
     /// stack to manage which object keys to keep
     std::vector<bool> key_keep_stack {}; // NOLINT(readability-redundant-member-init)
     /// helper to hold the reference for the next object element
     BasicJsonType* object_element = nullptr;
     /// whether a syntax error occurred
     bool errored = false;
     /// callback function
     const parser_callback_t callback = nullptr;
     /// whether to throw exceptions in case of errors
     const bool allow_exceptions = true;
     /// a discarded value for the callback
     BasicJsonType discarded = BasicJsonType::value_t::discarded;
     /// the lexer reference to obtain the current position
     lexer_t* m_lexer_ref = nullptr;
 };
 
 template<typename BasicJsonType>
 class json_sax_acceptor
 {
   public:
     using number_integer_t = typename BasicJsonType::number_integer_t;
     using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
     using number_float_t = typename BasicJsonType::number_float_t;
     using string_t = typename BasicJsonType::string_t;
     using binary_t = typename BasicJsonType::binary_t;
 
     bool null()
     {
         return true;
     }
 
     bool boolean(bool /*unused*/)
     {
         return true;
     }
 
     bool number_integer(number_integer_t /*unused*/)
     {
         return true;
     }
 
     bool number_unsigned(number_unsigned_t /*unused*/)
     {
         return true;
     }
 
     bool number_float(number_float_t /*unused*/, const string_t& /*unused*/)
     {
         return true;
     }
 
     bool string(string_t& /*unused*/)
     {
         return true;
     }
 
     bool binary(binary_t& /*unused*/)
     {
         return true;
     }
 
     bool start_object(std::size_t /*unused*/ = detail::unknown_size())
     {
         return true;
     }
 
     bool key(string_t& /*unused*/)
     {
         return true;
     }
 
     bool end_object()
     {
         return true;
     }
 
     bool start_array(std::size_t /*unused*/ = detail::unknown_size())
     {
         return true;
     }
 
     bool end_array()
     {
         return true;
     }
 
     bool parse_error(std::size_t /*unused*/, const std::string& /*unused*/, const detail::exception& /*unused*/)
     {
         return false;
     }
 };
 
 }  // namespace detail
 NLOHMANN_JSON_NAMESPACE_END

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