update nlohmann modernjson to v3.4 (with bson support)

6 files changed, 1073 insertions, 550 deletions

diff --git a/include/lib/modernjson/detail/input/binary_reader.hpp b/include/lib/modernjson/detail/input/binary_reader.hpp
index 103cbf7..637569a 100644
--- a/include/lib/modernjson/detail/input/binary_reader.hpp
+++ b/include/lib/modernjson/detail/input/binary_reader.hpp
@@ -68,6 +68,10 @@ class binary_reader
 
         switch (format)
         {
+            case input_format_t::bson:
+                result = parse_bson_internal();
+                break;
+
             case input_format_t::cbor:
                 result = parse_cbor_internal();
                 break;
@@ -100,7 +104,8 @@ class binary_reader
 
             if (JSON_UNLIKELY(current != std::char_traits<char>::eof()))
             {
-                return sax->parse_error(chars_read, get_token_string(), parse_error::create(110, chars_read, "expected end of input"));
+                return sax->parse_error(chars_read, get_token_string(),
+                                        parse_error::create(110, chars_read, exception_message(format, "expected end of input; last byte: 0x" + get_token_string(), "value")));
             }
         }
 
@@ -120,6 +125,225 @@ class binary_reader
     }
 
   private:
+    //////////
+    // BSON //
+    //////////
+
+    /*!
+    @brief Reads in a BSON-object and passes it to the SAX-parser.
+    @return whether a valid BSON-value was passed to the SAX parser
+    */
+    bool parse_bson_internal()
+    {
+        std::int32_t document_size;
+        get_number<std::int32_t, true>(input_format_t::bson, document_size);
+
+        if (JSON_UNLIKELY(not sax->start_object(std::size_t(-1))))
+        {
+            return false;
+        }
+
+        if (JSON_UNLIKELY(not parse_bson_element_list(/*is_array*/false)))
+        {
+            return false;
+        }
+
+        return sax->end_object();
+    }
+
+    /*!
+    @brief Parses a C-style string from the BSON input.
+    @param[in, out] result  A reference to the string variable where the read
+                            string is to be stored.
+    @return `true` if the \x00-byte indicating the end of the string was
+             encountered before the EOF; false` indicates an unexpected EOF.
+    */
+    bool get_bson_cstr(string_t& result)
+    {
+        auto out = std::back_inserter(result);
+        while (true)
+        {
+            get();
+            if (JSON_UNLIKELY(not unexpect_eof(input_format_t::bson, "cstring")))
+            {
+                return false;
+            }
+            if (current == 0x00)
+            {
+                return true;
+            }
+            *out++ = static_cast<char>(current);
+        }
+
+        return true;
+    }
+
+    /*!
+    @brief Parses a zero-terminated string of length @a len from the BSON
+           input.
+    @param[in] len  The length (including the zero-byte at the end) of the
+                    string to be read.
+    @param[in, out] result  A reference to the string variable where the read
+                            string is to be stored.
+    @tparam NumberType The type of the length @a len
+    @pre len >= 1
+    @return `true` if the string was successfully parsed
+    */
+    template<typename NumberType>
+    bool get_bson_string(const NumberType len, string_t& result)
+    {
+        if (JSON_UNLIKELY(len < 1))
+        {
+            auto last_token = get_token_string();
+            return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::bson, "string length must be at least 1, is " + std::to_string(len), "string")));
+        }
+
+        return get_string(input_format_t::bson, len - static_cast<NumberType>(1), result) and get() != std::char_traits<char>::eof();
+    }
+
+    /*!
+    @brief Read a BSON document element of the given @a element_type.
+    @param[in] element_type The BSON element type, c.f. http://bsonspec.org/spec.html
+    @param[in] element_type_parse_position The position in the input stream,
+               where the `element_type` was read.
+    @warning Not all BSON element types are supported yet. An unsupported
+             @a element_type will give rise to a parse_error.114:
+             Unsupported BSON record type 0x...
+    @return whether a valid BSON-object/array was passed to the SAX parser
+    */
+    bool parse_bson_element_internal(const int element_type,
+                                     const std::size_t element_type_parse_position)
+    {
+        switch (element_type)
+        {
+            case 0x01: // double
+            {
+                double number;
+                return get_number<double, true>(input_format_t::bson, number) and sax->number_float(static_cast<number_float_t>(number), "");
+            }
+
+            case 0x02: // string
+            {
+                std::int32_t len;
+                string_t value;
+                return get_number<std::int32_t, true>(input_format_t::bson, len) and get_bson_string(len, value) and sax->string(value);
+            }
+
+            case 0x03: // object
+            {
+                return parse_bson_internal();
+            }
+
+            case 0x04: // array
+            {
+                return parse_bson_array();
+            }
+
+            case 0x08: // boolean
+            {
+                return sax->boolean(get() != 0);
+            }
+
+            case 0x0A: // null
+            {
+                return sax->null();
+            }
+
+            case 0x10: // int32
+            {
+                std::int32_t value;
+                return get_number<std::int32_t, true>(input_format_t::bson, value) and sax->number_integer(value);
+            }
+
+            case 0x12: // int64
+            {
+                std::int64_t value;
+                return get_number<std::int64_t, true>(input_format_t::bson, value) and sax->number_integer(value);
+            }
+
+            default: // anything else not supported (yet)
+            {
+                char cr[3];
+                (std::snprintf)(cr, sizeof(cr), "%.2hhX", static_cast<unsigned char>(element_type));
+                return sax->parse_error(element_type_parse_position, std::string(cr), parse_error::create(114, element_type_parse_position, "Unsupported BSON record type 0x" + std::string(cr)));
+            }
+        }
+    }
+
+    /*!
+    @brief Read a BSON element list (as specified in the BSON-spec)
+
+    The same binary layout is used for objects and arrays, hence it must be
+    indicated with the argument @a is_array which one is expected
+    (true --> array, false --> object).
+
+    @param[in] is_array Determines if the element list being read is to be
+                        treated as an object (@a is_array == false), or as an
+                        array (@a is_array == true).
+    @return whether a valid BSON-object/array was passed to the SAX parser
+    */
+    bool parse_bson_element_list(const bool is_array)
+    {
+        string_t key;
+        while (int element_type = get())
+        {
+            if (JSON_UNLIKELY(not unexpect_eof(input_format_t::bson, "element list")))
+            {
+                return false;
+            }
+
+            const std::size_t element_type_parse_position = chars_read;
+            if (JSON_UNLIKELY(not get_bson_cstr(key)))
+            {
+                return false;
+            }
+
+            if (not is_array)
+            {
+                if (not sax->key(key))
+                {
+                    return false;
+                }
+            }
+
+            if (JSON_UNLIKELY(not parse_bson_element_internal(element_type, element_type_parse_position)))
+            {
+                return false;
+            }
+
+            // get_bson_cstr only appends
+            key.clear();
+        }
+
+        return true;
+    }
+
+    /*!
+    @brief Reads an array from the BSON input and passes it to the SAX-parser.
+    @return whether a valid BSON-array was passed to the SAX parser
+    */
+    bool parse_bson_array()
+    {
+        std::int32_t document_size;
+        get_number<std::int32_t, true>(input_format_t::bson, document_size);
+
+        if (JSON_UNLIKELY(not sax->start_array(std::size_t(-1))))
+        {
+            return false;
+        }
+
+        if (JSON_UNLIKELY(not parse_bson_element_list(/*is_array*/true)))
+        {
+            return false;
+        }
+
+        return sax->end_array();
+    }
+
+    //////////
+    // CBOR //
+    //////////
+
     /*!
     @param[in] get_char  whether a new character should be retrieved from the
                          input (true, default) or whether the last read
@@ -133,7 +357,7 @@ class binary_reader
         {
             // EOF
             case std::char_traits<char>::eof():
-                return unexpect_eof();
+                return unexpect_eof(input_format_t::cbor, "value");
 
             // Integer 0x00..0x17 (0..23)
             case 0x00:
@@ -165,25 +389,25 @@ class binary_reader
             case 0x18: // Unsigned integer (one-byte uint8_t follows)
             {
                 uint8_t number;
-                return get_number(number) and sax->number_unsigned(number);
+                return get_number(input_format_t::cbor, number) and sax->number_unsigned(number);
             }
 
             case 0x19: // Unsigned integer (two-byte uint16_t follows)
             {
                 uint16_t number;
-                return get_number(number) and sax->number_unsigned(number);
+                return get_number(input_format_t::cbor, number) and sax->number_unsigned(number);
             }
 
             case 0x1A: // Unsigned integer (four-byte uint32_t follows)
             {
                 uint32_t number;
-                return get_number(number) and sax->number_unsigned(number);
+                return get_number(input_format_t::cbor, number) and sax->number_unsigned(number);
             }
 
             case 0x1B: // Unsigned integer (eight-byte uint64_t follows)
             {
                 uint64_t number;
-                return get_number(number) and sax->number_unsigned(number);
+                return get_number(input_format_t::cbor, number) and sax->number_unsigned(number);
             }
 
             // Negative integer -1-0x00..-1-0x17 (-1..-24)
@@ -216,25 +440,25 @@ class binary_reader
             case 0x38: // Negative integer (one-byte uint8_t follows)
             {
                 uint8_t number;
-                return get_number(number) and sax->number_integer(static_cast<number_integer_t>(-1) - number);
+                return get_number(input_format_t::cbor, number) and sax->number_integer(static_cast<number_integer_t>(-1) - number);
             }
 
             case 0x39: // Negative integer -1-n (two-byte uint16_t follows)
             {
                 uint16_t number;
-                return get_number(number) and sax->number_integer(static_cast<number_integer_t>(-1) - number);
+                return get_number(input_format_t::cbor, number) and sax->number_integer(static_cast<number_integer_t>(-1) - number);
             }
 
             case 0x3A: // Negative integer -1-n (four-byte uint32_t follows)
             {
                 uint32_t number;
-                return get_number(number) and sax->number_integer(static_cast<number_integer_t>(-1) - number);
+                return get_number(input_format_t::cbor, number) and sax->number_integer(static_cast<number_integer_t>(-1) - number);
             }
 
             case 0x3B: // Negative integer -1-n (eight-byte uint64_t follows)
             {
                 uint64_t number;
-                return get_number(number) and sax->number_integer(static_cast<number_integer_t>(-1)
+                return get_number(input_format_t::cbor, number) and sax->number_integer(static_cast<number_integer_t>(-1)
                         - static_cast<number_integer_t>(number));
             }
 
@@ -303,25 +527,25 @@ class binary_reader
             case 0x98: // array (one-byte uint8_t for n follows)
             {
                 uint8_t len;
-                return get_number(len) and get_cbor_array(static_cast<std::size_t>(len));
+                return get_number(input_format_t::cbor, len) and get_cbor_array(static_cast<std::size_t>(len));
             }
 
             case 0x99: // array (two-byte uint16_t for n follow)
             {
                 uint16_t len;
-                return get_number(len) and get_cbor_array(static_cast<std::size_t>(len));
+                return get_number(input_format_t::cbor, len) and get_cbor_array(static_cast<std::size_t>(len));
             }
 
             case 0x9A: // array (four-byte uint32_t for n follow)
             {
                 uint32_t len;
-                return get_number(len) and get_cbor_array(static_cast<std::size_t>(len));
+                return get_number(input_format_t::cbor, len) and get_cbor_array(static_cast<std::size_t>(len));
             }
 
             case 0x9B: // array (eight-byte uint64_t for n follow)
             {
                 uint64_t len;
-                return get_number(len) and get_cbor_array(static_cast<std::size_t>(len));
+                return get_number(input_format_t::cbor, len) and get_cbor_array(static_cast<std::size_t>(len));
             }
 
             case 0x9F: // array (indefinite length)
@@ -357,25 +581,25 @@ class binary_reader
             case 0xB8: // map (one-byte uint8_t for n follows)
             {
                 uint8_t len;
-                return get_number(len) and get_cbor_object(static_cast<std::size_t>(len));
+                return get_number(input_format_t::cbor, len) and get_cbor_object(static_cast<std::size_t>(len));
             }
 
             case 0xB9: // map (two-byte uint16_t for n follow)
             {
                 uint16_t len;
-                return get_number(len) and get_cbor_object(static_cast<std::size_t>(len));
+                return get_number(input_format_t::cbor, len) and get_cbor_object(static_cast<std::size_t>(len));
             }
 
             case 0xBA: // map (four-byte uint32_t for n follow)
             {
                 uint32_t len;
-                return get_number(len) and get_cbor_object(static_cast<std::size_t>(len));
+                return get_number(input_format_t::cbor, len) and get_cbor_object(static_cast<std::size_t>(len));
             }
 
             case 0xBB: // map (eight-byte uint64_t for n follow)
             {
                 uint64_t len;
-                return get_number(len) and get_cbor_object(static_cast<std::size_t>(len));
+                return get_number(input_format_t::cbor, len) and get_cbor_object(static_cast<std::size_t>(len));
             }
 
             case 0xBF: // map (indefinite length)
@@ -392,17 +616,20 @@ class binary_reader
 
             case 0xF9: // Half-Precision Float (two-byte IEEE 754)
             {
-                const int byte1 = get();
-                if (JSON_UNLIKELY(not unexpect_eof()))
+                const int byte1_raw = get();
+                if (JSON_UNLIKELY(not unexpect_eof(input_format_t::cbor, "number")))
                 {
                     return false;
                 }
-                const int byte2 = get();
-                if (JSON_UNLIKELY(not unexpect_eof()))
+                const int byte2_raw = get();
+                if (JSON_UNLIKELY(not unexpect_eof(input_format_t::cbor, "number")))
                 {
                     return false;
                 }
 
+                const auto byte1 = static_cast<unsigned char>(byte1_raw);
+                const auto byte2 = static_cast<unsigned char>(byte2_raw);
+
                 // code from RFC 7049, Appendix D, Figure 3:
                 // As half-precision floating-point numbers were only added
                 // to IEEE 754 in 2008, today's programming platforms often
@@ -438,24 +665,209 @@ class binary_reader
             case 0xFA: // Single-Precision Float (four-byte IEEE 754)
             {
                 float number;
-                return get_number(number) and sax->number_float(static_cast<number_float_t>(number), "");
+                return get_number(input_format_t::cbor, number) and sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0xFB: // Double-Precision Float (eight-byte IEEE 754)
             {
                 double number;
-                return get_number(number) and sax->number_float(static_cast<number_float_t>(number), "");
+                return get_number(input_format_t::cbor, number) and sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             default: // anything else (0xFF is handled inside the other types)
             {
                 auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, "error reading CBOR; last byte: 0x" + last_token));
+                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::cbor, "invalid byte: 0x" + last_token, "value")));
+            }
+        }
+    }
+
+    /*!
+    @brief reads a CBOR string
+
+    This function first reads starting bytes to determine the expected
+    string length and then copies this number of bytes into a string.
+    Additionally, CBOR's strings with indefinite lengths are supported.
+
+    @param[out] result  created string
+
+    @return whether string creation completed
+    */
+    bool get_cbor_string(string_t& result)
+    {
+        if (JSON_UNLIKELY(not unexpect_eof(input_format_t::cbor, "string")))
+        {
+            return false;
+        }
+
+        switch (current)
+        {
+            // UTF-8 string (0x00..0x17 bytes follow)
+            case 0x60:
+            case 0x61:
+            case 0x62:
+            case 0x63:
+            case 0x64:
+            case 0x65:
+            case 0x66:
+            case 0x67:
+            case 0x68:
+            case 0x69:
+            case 0x6A:
+            case 0x6B:
+            case 0x6C:
+            case 0x6D:
+            case 0x6E:
+            case 0x6F:
+            case 0x70:
+            case 0x71:
+            case 0x72:
+            case 0x73:
+            case 0x74:
+            case 0x75:
+            case 0x76:
+            case 0x77:
+            {
+                return get_string(input_format_t::cbor, current & 0x1F, result);
+            }
+
+            case 0x78: // UTF-8 string (one-byte uint8_t for n follows)
+            {
+                uint8_t len;
+                return get_number(input_format_t::cbor, len) and get_string(input_format_t::cbor, len, result);
+            }
+
+            case 0x79: // UTF-8 string (two-byte uint16_t for n follow)
+            {
+                uint16_t len;
+                return get_number(input_format_t::cbor, len) and get_string(input_format_t::cbor, len, result);
+            }
+
+            case 0x7A: // UTF-8 string (four-byte uint32_t for n follow)
+            {
+                uint32_t len;
+                return get_number(input_format_t::cbor, len) and get_string(input_format_t::cbor, len, result);
+            }
+
+            case 0x7B: // UTF-8 string (eight-byte uint64_t for n follow)
+            {
+                uint64_t len;
+                return get_number(input_format_t::cbor, len) and get_string(input_format_t::cbor, len, result);
+            }
+
+            case 0x7F: // UTF-8 string (indefinite length)
+            {
+                while (get() != 0xFF)
+                {
+                    string_t chunk;
+                    if (not get_cbor_string(chunk))
+                    {
+                        return false;
+                    }
+                    result.append(chunk);
+                }
+                return true;
+            }
+
+            default:
+            {
+                auto last_token = get_token_string();
+                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::cbor, "expected length specification (0x60-0x7B) or indefinite string type (0x7F); last byte: 0x" + last_token, "string")));
             }
         }
     }
 
     /*!
+    @param[in] len  the length of the array or std::size_t(-1) for an
+                    array of indefinite size
+    @return whether array creation completed
+    */
+    bool get_cbor_array(const std::size_t len)
+    {
+        if (JSON_UNLIKELY(not sax->start_array(len)))
+        {
+            return false;
+        }
+
+        if (len != std::size_t(-1))
+        {
+            for (std::size_t i = 0; i < len; ++i)
+            {
+                if (JSON_UNLIKELY(not parse_cbor_internal()))
+                {
+                    return false;
+                }
+            }
+        }
+        else
+        {
+            while (get() != 0xFF)
+            {
+                if (JSON_UNLIKELY(not parse_cbor_internal(false)))
+                {
+                    return false;
+                }
+            }
+        }
+
+        return sax->end_array();
+    }
+
+    /*!
+    @param[in] len  the length of the object or std::size_t(-1) for an
+                    object of indefinite size
+    @return whether object creation completed
+    */
+    bool get_cbor_object(const std::size_t len)
+    {
+        if (not JSON_UNLIKELY(sax->start_object(len)))
+        {
+            return false;
+        }
+
+        string_t key;
+        if (len != std::size_t(-1))
+        {
+            for (std::size_t i = 0; i < len; ++i)
+            {
+                get();
+                if (JSON_UNLIKELY(not get_cbor_string(key) or not sax->key(key)))
+                {
+                    return false;
+                }
+
+                if (JSON_UNLIKELY(not parse_cbor_internal()))
+                {
+                    return false;
+                }
+                key.clear();
+            }
+        }
+        else
+        {
+            while (get() != 0xFF)
+            {
+                if (JSON_UNLIKELY(not get_cbor_string(key) or not sax->key(key)))
+                {
+                    return false;
+                }
+
+                if (JSON_UNLIKELY(not parse_cbor_internal()))
+                {
+                    return false;
+                }
+                key.clear();
+            }
+        }
+
+        return sax->end_object();
+    }
+
+    /////////////
+    // MsgPack //
+    /////////////
+
+    /*!
     @return whether a valid MessagePack value was passed to the SAX parser
     */
     bool parse_msgpack_internal()
@@ -464,7 +876,7 @@ class binary_reader
         {
             // EOF
             case std::char_traits<char>::eof():
-                return unexpect_eof();
+                return unexpect_eof(input_format_t::msgpack, "value");
 
             // positive fixint
             case 0x00:
@@ -685,61 +1097,61 @@ class binary_reader
             case 0xCA: // float 32
             {
                 float number;
-                return get_number(number) and sax->number_float(static_cast<number_float_t>(number), "");
+                return get_number(input_format_t::msgpack, number) and sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0xCB: // float 64
             {
                 double number;
-                return get_number(number) and sax->number_float(static_cast<number_float_t>(number), "");
+                return get_number(input_format_t::msgpack, number) and sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0xCC: // uint 8
             {
                 uint8_t number;
-                return get_number(number) and sax->number_unsigned(number);
+                return get_number(input_format_t::msgpack, number) and sax->number_unsigned(number);
             }
 
             case 0xCD: // uint 16
             {
                 uint16_t number;
-                return get_number(number) and sax->number_unsigned(number);
+                return get_number(input_format_t::msgpack, number) and sax->number_unsigned(number);
             }
 
             case 0xCE: // uint 32
             {
                 uint32_t number;
-                return get_number(number) and sax->number_unsigned(number);
+                return get_number(input_format_t::msgpack, number) and sax->number_unsigned(number);
             }
 
             case 0xCF: // uint 64
             {
                 uint64_t number;
-                return get_number(number) and sax->number_unsigned(number);
+                return get_number(input_format_t::msgpack, number) and sax->number_unsigned(number);
             }
 
             case 0xD0: // int 8
             {
                 int8_t number;
-                return get_number(number) and sax->number_integer(number);
+                return get_number(input_format_t::msgpack, number) and sax->number_integer(number);
             }
 
             case 0xD1: // int 16
             {
                 int16_t number;
-                return get_number(number) and sax->number_integer(number);
+                return get_number(input_format_t::msgpack, number) and sax->number_integer(number);
             }
 
             case 0xD2: // int 32
             {
                 int32_t number;
-                return get_number(number) and sax->number_integer(number);
+                return get_number(input_format_t::msgpack, number) and sax->number_integer(number);
             }
 
             case 0xD3: // int 64
             {
                 int64_t number;
-                return get_number(number) and sax->number_integer(number);
+                return get_number(input_format_t::msgpack, number) and sax->number_integer(number);
             }
 
             case 0xD9: // str 8
@@ -753,25 +1165,25 @@ class binary_reader
             case 0xDC: // array 16
             {
                 uint16_t len;
-                return get_number(len) and get_msgpack_array(static_cast<std::size_t>(len));
+                return get_number(input_format_t::msgpack, len) and get_msgpack_array(static_cast<std::size_t>(len));
             }
 
             case 0xDD: // array 32
             {
                 uint32_t len;
-                return get_number(len) and get_msgpack_array(static_cast<std::size_t>(len));
+                return get_number(input_format_t::msgpack, len) and get_msgpack_array(static_cast<std::size_t>(len));
             }
 
             case 0xDE: // map 16
             {
                 uint16_t len;
-                return get_number(len) and get_msgpack_object(static_cast<std::size_t>(len));
+                return get_number(input_format_t::msgpack, len) and get_msgpack_object(static_cast<std::size_t>(len));
             }
 
             case 0xDF: // map 32
             {
                 uint32_t len;
-                return get_number(len) and get_msgpack_object(static_cast<std::size_t>(len));
+                return get_number(input_format_t::msgpack, len) and get_msgpack_object(static_cast<std::size_t>(len));
             }
 
             // negative fixint
@@ -812,302 +1224,12 @@ class binary_reader
             default: // anything else
             {
                 auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, "error reading MessagePack; last byte: 0x" + last_token));
+                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::msgpack, "invalid byte: 0x" + last_token, "value")));
             }
         }
     }
 
     /*!
-    @param[in] get_char  whether a new character should be retrieved from the
-                         input (true, default) or whether the last read
-                         character should be considered instead
-
-    @return whether a valid UBJSON value was passed to the SAX parser
-    */
-    bool parse_ubjson_internal(const bool get_char = true)
-    {
-        return get_ubjson_value(get_char ? get_ignore_noop() : current);
-    }
-
-    /*!
-    @brief get next character from the input
-
-    This function provides the interface to the used input adapter. It does
-    not throw in case the input reached EOF, but returns a -'ve valued
-    `std::char_traits<char>::eof()` in that case.
-
-    @return character read from the input
-    */
-    int get()
-    {
-        ++chars_read;
-        return (current = ia->get_character());
-    }
-
-    /*!
-    @return character read from the input after ignoring all 'N' entries
-    */
-    int get_ignore_noop()
-    {
-        do
-        {
-            get();
-        }
-        while (current == 'N');
-
-        return current;
-    }
-
-    /*
-    @brief read a number from the input
-
-    @tparam NumberType the type of the number
-    @param[out] result  number of type @a NumberType
-
-    @return whether conversion completed
-
-    @note This function needs to respect the system's endianess, because
-          bytes in CBOR, MessagePack, and UBJSON are stored in network order
-          (big endian) and therefore need reordering on little endian systems.
-    */
-    template<typename NumberType>
-    bool get_number(NumberType& result)
-    {
-        // step 1: read input into array with system's byte order
-        std::array<uint8_t, sizeof(NumberType)> vec;
-        for (std::size_t i = 0; i < sizeof(NumberType); ++i)
-        {
-            get();
-            if (JSON_UNLIKELY(not unexpect_eof()))
-            {
-                return false;
-            }
-
-            // reverse byte order prior to conversion if necessary
-            if (is_little_endian)
-            {
-                vec[sizeof(NumberType) - i - 1] = static_cast<uint8_t>(current);
-            }
-            else
-            {
-                vec[i] = static_cast<uint8_t>(current); // LCOV_EXCL_LINE
-            }
-        }
-
-        // step 2: convert array into number of type T and return
-        std::memcpy(&result, vec.data(), sizeof(NumberType));
-        return true;
-    }
-
-    /*!
-    @brief create a string by reading characters from the input
-
-    @tparam NumberType the type of the number
-    @param[in] len number of characters to read
-    @param[out] string created by reading @a len bytes
-
-    @return whether string creation completed
-
-    @note We can not reserve @a len bytes for the result, because @a len
-          may be too large. Usually, @ref unexpect_eof() detects the end of
-          the input before we run out of string memory.
-    */
-    template<typename NumberType>
-    bool get_string(const NumberType len, string_t& result)
-    {
-        bool success = true;
-        std::generate_n(std::back_inserter(result), len, [this, &success]()
-        {
-            get();
-            if (JSON_UNLIKELY(not unexpect_eof()))
-            {
-                success = false;
-            }
-            return static_cast<char>(current);
-        });
-        return success;
-    }
-
-    /*!
-    @brief reads a CBOR string
-
-    This function first reads starting bytes to determine the expected
-    string length and then copies this number of bytes into a string.
-    Additionally, CBOR's strings with indefinite lengths are supported.
-
-    @param[out] result  created string
-
-    @return whether string creation completed
-    */
-    bool get_cbor_string(string_t& result)
-    {
-        if (JSON_UNLIKELY(not unexpect_eof()))
-        {
-            return false;
-        }
-
-        switch (current)
-        {
-            // UTF-8 string (0x00..0x17 bytes follow)
-            case 0x60:
-            case 0x61:
-            case 0x62:
-            case 0x63:
-            case 0x64:
-            case 0x65:
-            case 0x66:
-            case 0x67:
-            case 0x68:
-            case 0x69:
-            case 0x6A:
-            case 0x6B:
-            case 0x6C:
-            case 0x6D:
-            case 0x6E:
-            case 0x6F:
-            case 0x70:
-            case 0x71:
-            case 0x72:
-            case 0x73:
-            case 0x74:
-            case 0x75:
-            case 0x76:
-            case 0x77:
-            {
-                return get_string(current & 0x1F, result);
-            }
-
-            case 0x78: // UTF-8 string (one-byte uint8_t for n follows)
-            {
-                uint8_t len;
-                return get_number(len) and get_string(len, result);
-            }
-
-            case 0x79: // UTF-8 string (two-byte uint16_t for n follow)
-            {
-                uint16_t len;
-                return get_number(len) and get_string(len, result);
-            }
-
-            case 0x7A: // UTF-8 string (four-byte uint32_t for n follow)
-            {
-                uint32_t len;
-                return get_number(len) and get_string(len, result);
-            }
-
-            case 0x7B: // UTF-8 string (eight-byte uint64_t for n follow)
-            {
-                uint64_t len;
-                return get_number(len) and get_string(len, result);
-            }
-
-            case 0x7F: // UTF-8 string (indefinite length)
-            {
-                while (get() != 0xFF)
-                {
-                    string_t chunk;
-                    if (not get_cbor_string(chunk))
-                    {
-                        return false;
-                    }
-                    result.append(chunk);
-                }
-                return true;
-            }
-
-            default:
-            {
-                auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, "expected a CBOR string; last byte: 0x" + last_token));
-            }
-        }
-    }
-
-    /*!
-    @param[in] len  the length of the array or std::size_t(-1) for an
-                    array of indefinite size
-    @return whether array creation completed
-    */
-    bool get_cbor_array(const std::size_t len)
-    {
-        if (JSON_UNLIKELY(not sax->start_array(len)))
-        {
-            return false;
-        }
-
-        if (len != std::size_t(-1))
-            for (std::size_t i = 0; i < len; ++i)
-            {
-                if (JSON_UNLIKELY(not parse_cbor_internal()))
-                {
-                    return false;
-                }
-            }
-        else
-        {
-            while (get() != 0xFF)
-            {
-                if (JSON_UNLIKELY(not parse_cbor_internal(false)))
-                {
-                    return false;
-                }
-            }
-        }
-
-        return sax->end_array();
-    }
-
-    /*!
-    @param[in] len  the length of the object or std::size_t(-1) for an
-                    object of indefinite size
-    @return whether object creation completed
-    */
-    bool get_cbor_object(const std::size_t len)
-    {
-        if (not JSON_UNLIKELY(sax->start_object(len)))
-        {
-            return false;
-        }
-
-        string_t key;
-        if (len != std::size_t(-1))
-        {
-            for (std::size_t i = 0; i < len; ++i)
-            {
-                get();
-                if (JSON_UNLIKELY(not get_cbor_string(key) or not sax->key(key)))
-                {
-                    return false;
-                }
-
-                if (JSON_UNLIKELY(not parse_cbor_internal()))
-                {
-                    return false;
-                }
-                key.clear();
-            }
-        }
-        else
-        {
-            while (get() != 0xFF)
-            {
-                if (JSON_UNLIKELY(not get_cbor_string(key) or not sax->key(key)))
-                {
-                    return false;
-                }
-
-                if (JSON_UNLIKELY(not parse_cbor_internal()))
-                {
-                    return false;
-                }
-                key.clear();
-            }
-        }
-
-        return sax->end_object();
-    }
-
-    /*!
     @brief reads a MessagePack string
 
     This function first reads starting bytes to determine the expected
@@ -1119,7 +1241,7 @@ class binary_reader
     */
     bool get_msgpack_string(string_t& result)
     {
-        if (JSON_UNLIKELY(not unexpect_eof()))
+        if (JSON_UNLIKELY(not unexpect_eof(input_format_t::msgpack, "string")))
         {
             return false;
         }
@@ -1160,31 +1282,31 @@ class binary_reader
             case 0xBE:
             case 0xBF:
             {
-                return get_string(current & 0x1F, result);
+                return get_string(input_format_t::msgpack, current & 0x1F, result);
             }
 
             case 0xD9: // str 8
             {
                 uint8_t len;
-                return get_number(len) and get_string(len, result);
+                return get_number(input_format_t::msgpack, len) and get_string(input_format_t::msgpack, len, result);
             }
 
             case 0xDA: // str 16
             {
                 uint16_t len;
-                return get_number(len) and get_string(len, result);
+                return get_number(input_format_t::msgpack, len) and get_string(input_format_t::msgpack, len, result);
             }
 
             case 0xDB: // str 32
             {
                 uint32_t len;
-                return get_number(len) and get_string(len, result);
+                return get_number(input_format_t::msgpack, len) and get_string(input_format_t::msgpack, len, result);
             }
 
             default:
             {
                 auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, "expected a MessagePack string; last byte: 0x" + last_token));
+                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::msgpack, "expected length specification (0xA0-0xBF, 0xD9-0xDB); last byte: 0x" + last_token, "string")));
             }
         }
     }
@@ -1241,6 +1363,22 @@ class binary_reader
         return sax->end_object();
     }
 
+    ////////////
+    // UBJSON //
+    ////////////
+
+    /*!
+    @param[in] get_char  whether a new character should be retrieved from the
+                         input (true, default) or whether the last read
+                         character should be considered instead
+
+    @return whether a valid UBJSON value was passed to the SAX parser
+    */
+    bool parse_ubjson_internal(const bool get_char = true)
+    {
+        return get_ubjson_value(get_char ? get_ignore_noop() : current);
+    }
+
     /*!
     @brief reads a UBJSON string
 
@@ -1262,7 +1400,7 @@ class binary_reader
             get();  // TODO: may we ignore N here?
         }
 
-        if (JSON_UNLIKELY(not unexpect_eof()))
+        if (JSON_UNLIKELY(not unexpect_eof(input_format_t::ubjson, "value")))
         {
             return false;
         }
@@ -1272,36 +1410,36 @@ class binary_reader
             case 'U':
             {
                 uint8_t len;
-                return get_number(len) and get_string(len, result);
+                return get_number(input_format_t::ubjson, len) and get_string(input_format_t::ubjson, len, result);
             }
 
             case 'i':
             {
                 int8_t len;
-                return get_number(len) and get_string(len, result);
+                return get_number(input_format_t::ubjson, len) and get_string(input_format_t::ubjson, len, result);
             }
 
             case 'I':
             {
                 int16_t len;
-                return get_number(len) and get_string(len, result);
+                return get_number(input_format_t::ubjson, len) and get_string(input_format_t::ubjson, len, result);
             }
 
             case 'l':
             {
                 int32_t len;
-                return get_number(len) and get_string(len, result);
+                return get_number(input_format_t::ubjson, len) and get_string(input_format_t::ubjson, len, result);
             }
 
             case 'L':
             {
                 int64_t len;
-                return get_number(len) and get_string(len, result);
+                return get_number(input_format_t::ubjson, len) and get_string(input_format_t::ubjson, len, result);
             }
 
             default:
                 auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, "expected a UBJSON string; last byte: 0x" + last_token));
+                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::ubjson, "expected length type specification (U, i, I, l, L); last byte: 0x" + last_token, "string")));
         }
     }
 
@@ -1316,7 +1454,7 @@ class binary_reader
             case 'U':
             {
                 uint8_t number;
-                if (JSON_UNLIKELY(not get_number(number)))
+                if (JSON_UNLIKELY(not get_number(input_format_t::ubjson, number)))
                 {
                     return false;
                 }
@@ -1327,7 +1465,7 @@ class binary_reader
             case 'i':
             {
                 int8_t number;
-                if (JSON_UNLIKELY(not get_number(number)))
+                if (JSON_UNLIKELY(not get_number(input_format_t::ubjson, number)))
                 {
                     return false;
                 }
@@ -1338,7 +1476,7 @@ class binary_reader
             case 'I':
             {
                 int16_t number;
-                if (JSON_UNLIKELY(not get_number(number)))
+                if (JSON_UNLIKELY(not get_number(input_format_t::ubjson, number)))
                 {
                     return false;
                 }
@@ -1349,7 +1487,7 @@ class binary_reader
             case 'l':
             {
                 int32_t number;
-                if (JSON_UNLIKELY(not get_number(number)))
+                if (JSON_UNLIKELY(not get_number(input_format_t::ubjson, number)))
                 {
                     return false;
                 }
@@ -1360,7 +1498,7 @@ class binary_reader
             case 'L':
             {
                 int64_t number;
-                if (JSON_UNLIKELY(not get_number(number)))
+                if (JSON_UNLIKELY(not get_number(input_format_t::ubjson, number)))
                 {
                     return false;
                 }
@@ -1371,7 +1509,7 @@ class binary_reader
             default:
             {
                 auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, "byte after '#' must denote a number type; last byte: 0x" + last_token));
+                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::ubjson, "expected length type specification (U, i, I, l, L) after '#'; last byte: 0x" + last_token, "size")));
             }
         }
     }
@@ -1396,7 +1534,7 @@ class binary_reader
         if (current == '$')
         {
             result.second = get();  // must not ignore 'N', because 'N' maybe the type
-            if (JSON_UNLIKELY(not unexpect_eof()))
+            if (JSON_UNLIKELY(not unexpect_eof(input_format_t::ubjson, "type")))
             {
                 return false;
             }
@@ -1404,12 +1542,12 @@ class binary_reader
             get_ignore_noop();
             if (JSON_UNLIKELY(current != '#'))
             {
-                if (JSON_UNLIKELY(not unexpect_eof()))
+                if (JSON_UNLIKELY(not unexpect_eof(input_format_t::ubjson, "value")))
                 {
                     return false;
                 }
                 auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, "expected '#' after UBJSON type information; last byte: 0x" + last_token));
+                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::ubjson, "expected '#' after type information; last byte: 0x" + last_token, "size")));
             }
 
             return get_ubjson_size_value(result.first);
@@ -1430,7 +1568,7 @@ class binary_reader
         switch (prefix)
         {
             case std::char_traits<char>::eof():  // EOF
-                return unexpect_eof();
+                return unexpect_eof(input_format_t::ubjson, "value");
 
             case 'T':  // true
                 return sax->boolean(true);
@@ -1443,56 +1581,56 @@ class binary_reader
             case 'U':
             {
                 uint8_t number;
-                return get_number(number) and sax->number_unsigned(number);
+                return get_number(input_format_t::ubjson, number) and sax->number_unsigned(number);
             }
 
             case 'i':
             {
                 int8_t number;
-                return get_number(number) and sax->number_integer(number);
+                return get_number(input_format_t::ubjson, number) and sax->number_integer(number);
             }
 
             case 'I':
             {
                 int16_t number;
-                return get_number(number) and sax->number_integer(number);
+                return get_number(input_format_t::ubjson, number) and sax->number_integer(number);
             }
 
             case 'l':
             {
                 int32_t number;
-                return get_number(number) and sax->number_integer(number);
+                return get_number(input_format_t::ubjson, number) and sax->number_integer(number);
             }
 
             case 'L':
             {
                 int64_t number;
-                return get_number(number) and sax->number_integer(number);
+                return get_number(input_format_t::ubjson, number) and sax->number_integer(number);
             }
 
             case 'd':
             {
                 float number;
-                return get_number(number) and sax->number_float(static_cast<number_float_t>(number), "");
+                return get_number(input_format_t::ubjson, number) and sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 'D':
             {
                 double number;
-                return get_number(number) and sax->number_float(static_cast<number_float_t>(number), "");
+                return get_number(input_format_t::ubjson, number) and sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 'C':  // char
             {
                 get();
-                if (JSON_UNLIKELY(not unexpect_eof()))
+                if (JSON_UNLIKELY(not unexpect_eof(input_format_t::ubjson, "char")))
                 {
                     return false;
                 }
                 if (JSON_UNLIKELY(current > 127))
                 {
                     auto last_token = get_token_string();
-                    return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, "byte after 'C' must be in range 0x00..0x7F; last byte: 0x" + last_token));
+                    return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::ubjson, "byte after 'C' must be in range 0x00..0x7F; last byte: 0x" + last_token, "char")));
                 }
                 string_t s(1, static_cast<char>(current));
                 return sax->string(s);
@@ -1513,7 +1651,7 @@ class binary_reader
             default: // anything else
             {
                 auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, "error reading UBJSON; last byte: 0x" + last_token));
+                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::ubjson, "invalid byte: 0x" + last_token, "value")));
             }
         }
     }
@@ -1655,14 +1793,124 @@ class binary_reader
         return sax->end_object();
     }
 
+    ///////////////////////
+    // Utility functions //
+    ///////////////////////
+
+    /*!
+    @brief get next character from the input
+
+    This function provides the interface to the used input adapter. It does
+    not throw in case the input reached EOF, but returns a -'ve valued
+    `std::char_traits<char>::eof()` in that case.
+
+    @return character read from the input
+    */
+    int get()
+    {
+        ++chars_read;
+        return (current = ia->get_character());
+    }
+
+    /*!
+    @return character read from the input after ignoring all 'N' entries
+    */
+    int get_ignore_noop()
+    {
+        do
+        {
+            get();
+        }
+        while (current == 'N');
+
+        return current;
+    }
+
+    /*
+    @brief read a number from the input
+
+    @tparam NumberType the type of the number
+    @param[in] format   the current format (for diagnostics)
+    @param[out] result  number of type @a NumberType
+
+    @return whether conversion completed
+
+    @note This function needs to respect the system's endianess, because
+          bytes in CBOR, MessagePack, and UBJSON are stored in network order
+          (big endian) and therefore need reordering on little endian systems.
+    */
+    template<typename NumberType, bool InputIsLittleEndian = false>
+    bool get_number(const input_format_t format, NumberType& result)
+    {
+        // step 1: read input into array with system's byte order
+        std::array<uint8_t, sizeof(NumberType)> vec;
+        for (std::size_t i = 0; i < sizeof(NumberType); ++i)
+        {
+            get();
+            if (JSON_UNLIKELY(not unexpect_eof(format, "number")))
+            {
+                return false;
+            }
+
+            // reverse byte order prior to conversion if necessary
+            if (is_little_endian && !InputIsLittleEndian)
+            {
+                vec[sizeof(NumberType) - i - 1] = static_cast<uint8_t>(current);
+            }
+            else
+            {
+                vec[i] = static_cast<uint8_t>(current); // LCOV_EXCL_LINE
+            }
+        }
+
+        // step 2: convert array into number of type T and return
+        std::memcpy(&result, vec.data(), sizeof(NumberType));
+        return true;
+    }
+
+    /*!
+    @brief create a string by reading characters from the input
+
+    @tparam NumberType the type of the number
+    @param[in] format the current format (for diagnostics)
+    @param[in] len number of characters to read
+    @param[out] result string created by reading @a len bytes
+
+    @return whether string creation completed
+
+    @note We can not reserve @a len bytes for the result, because @a len
+          may be too large. Usually, @ref unexpect_eof() detects the end of
+          the input before we run out of string memory.
+    */
+    template<typename NumberType>
+    bool get_string(const input_format_t format,
+                    const NumberType len,
+                    string_t& result)
+    {
+        bool success = true;
+        std::generate_n(std::back_inserter(result), len, [this, &success, &format]()
+        {
+            get();
+            if (JSON_UNLIKELY(not unexpect_eof(format, "string")))
+            {
+                success = false;
+            }
+            return static_cast<char>(current);
+        });
+        return success;
+    }
+
     /*!
+    @param[in] format   the current format (for diagnostics)
+    @param[in] context  further context information (for diagnostics)
     @return whether the last read character is not EOF
     */
-    bool unexpect_eof() const
+    bool unexpect_eof(const input_format_t format, const char* context) const
     {
         if (JSON_UNLIKELY(current == std::char_traits<char>::eof()))
         {
-            return sax->parse_error(chars_read, "<end of file>", parse_error::create(110, chars_read, "unexpected end of input"));
+            return sax->parse_error(chars_read, "<end of file>",
+                                    parse_error::create(110, chars_read, exception_message(format, "unexpected end of input", context)));
         }
         return true;
     }
@@ -1673,10 +1921,49 @@ class binary_reader
     std::string get_token_string() const
     {
         char cr[3];
-        snprintf(cr, 3, "%.2hhX", static_cast<unsigned char>(current));
+        (std::snprintf)(cr, 3, "%.2hhX", static_cast<unsigned char>(current));
         return std::string{cr};
     }
 
+    /*!
+    @param[in] format   the current format
+    @param[in] detail   a detailed error message
+    @param[in] context  further contect information
+    @return a message string to use in the parse_error exceptions
+    */
+    std::string exception_message(const input_format_t format,
+                                  const std::string& detail,
+                                  const std::string& context) const
+    {
+        std::string error_msg = "syntax error while parsing ";
+
+        switch (format)
+        {
+            case input_format_t::cbor:
+                error_msg += "CBOR";
+                break;
+
+            case input_format_t::msgpack:
+                error_msg += "MessagePack";
+                break;
+
+            case input_format_t::ubjson:
+                error_msg += "UBJSON";
+                break;
+
+            case input_format_t::bson:
+                error_msg += "BSON";
+                break;
+
+            // LCOV_EXCL_START
+            default:
+                assert(false);
+                // LCOV_EXCL_STOP
+        }
+
+        return error_msg + " " + context + ": " + detail;
+    }
+
   private:
     /// input adapter
     input_adapter_t ia = nullptr;
@@ -1693,5 +1980,5 @@ class binary_reader
     /// the SAX parser
     json_sax_t* sax = nullptr;
 };
-}
-}
+}  // namespace detail
+}  // namespace nlohmann
diff --git a/include/lib/modernjson/detail/input/input_adapters.hpp b/include/lib/modernjson/detail/input/input_adapters.hpp
index 5abaee3..dfb8caf 100644
--- a/include/lib/modernjson/detail/input/input_adapters.hpp
+++ b/include/lib/modernjson/detail/input/input_adapters.hpp
@@ -18,7 +18,7 @@ namespace nlohmann
 namespace detail
 {
 /// the supported input formats
-enum class input_format_t { json, cbor, msgpack, ubjson };
+enum class input_format_t { json, cbor, msgpack, ubjson, bson };
 
 ////////////////////
 // input adapters //
@@ -60,8 +60,8 @@ class input_stream_adapter : public input_adapter_protocol
     ~input_stream_adapter() override
     {
         // clear stream flags; we use underlying streambuf I/O, do not
-        // maintain ifstream flags
-        is.clear();
+        // maintain ifstream flags, except eof
+        is.clear(is.rdstate() & std::ios::eofbit);
     }
 
     explicit input_stream_adapter(std::istream& i)
@@ -71,13 +71,21 @@ class input_stream_adapter : public input_adapter_protocol
     // delete because of pointer members
     input_stream_adapter(const input_stream_adapter&) = delete;
     input_stream_adapter& operator=(input_stream_adapter&) = delete;
+    input_stream_adapter(input_stream_adapter&&) = delete;
+    input_stream_adapter& operator=(input_stream_adapter&&) = delete;
 
     // std::istream/std::streambuf use std::char_traits<char>::to_int_type, to
     // ensure that std::char_traits<char>::eof() and the character 0xFF do not
     // end up as the same value, eg. 0xFFFFFFFF.
     std::char_traits<char>::int_type get_character() override
     {
-        return sb.sbumpc();
+        auto res = sb.sbumpc();
+        // set eof manually, as we don't use the istream interface.
+        if (res == EOF)
+        {
+            is.clear(is.rdstate() | std::ios::eofbit);
+        }
+        return res;
     }
 
   private:
@@ -90,13 +98,16 @@ class input_stream_adapter : public input_adapter_protocol
 class input_buffer_adapter : public input_adapter_protocol
 {
   public:
-    input_buffer_adapter(const char* b, const std::size_t l)
+    input_buffer_adapter(const char* b, const std::size_t l) noexcept
         : cursor(b), limit(b + l)
     {}
 
     // delete because of pointer members
     input_buffer_adapter(const input_buffer_adapter&) = delete;
     input_buffer_adapter& operator=(input_buffer_adapter&) = delete;
+    input_buffer_adapter(input_buffer_adapter&&) = delete;
+    input_buffer_adapter& operator=(input_buffer_adapter&&) = delete;
+    ~input_buffer_adapter() override = default;
 
     std::char_traits<char>::int_type get_character() noexcept override
     {
@@ -115,38 +126,66 @@ class input_buffer_adapter : public input_adapter_protocol
     const char* const limit;
 };
 
-template<typename WideStringType>
-class wide_string_input_adapter : public input_adapter_protocol
+template<typename WideStringType, size_t T>
+struct wide_string_input_helper
 {
-  public:
-    explicit wide_string_input_adapter(const WideStringType& w) : str(w) {}
-
-    std::char_traits<char>::int_type get_character() noexcept override
+    // UTF-32
+    static void fill_buffer(const WideStringType& str, size_t& current_wchar, std::array<std::char_traits<char>::int_type, 4>& utf8_bytes, size_t& utf8_bytes_index, size_t& utf8_bytes_filled)
     {
-        // check if buffer needs to be filled
-        if (utf8_bytes_index == utf8_bytes_filled)
+        utf8_bytes_index = 0;
+
+        if (current_wchar == str.size())
+        {
+            utf8_bytes[0] = std::char_traits<char>::eof();
+            utf8_bytes_filled = 1;
+        }
+        else
         {
-            if (sizeof(typename WideStringType::value_type) == 2)
+            // get the current character
+            const auto wc = static_cast<int>(str[current_wchar++]);
+
+            // UTF-32 to UTF-8 encoding
+            if (wc < 0x80)
+            {
+                utf8_bytes[0] = wc;
+                utf8_bytes_filled = 1;
+            }
+            else if (wc <= 0x7FF)
+            {
+                utf8_bytes[0] = 0xC0 | ((wc >> 6) & 0x1F);
+                utf8_bytes[1] = 0x80 | (wc & 0x3F);
+                utf8_bytes_filled = 2;
+            }
+            else if (wc <= 0xFFFF)
             {
-                fill_buffer_utf16();
+                utf8_bytes[0] = 0xE0 | ((wc >> 12) & 0x0F);
+                utf8_bytes[1] = 0x80 | ((wc >> 6) & 0x3F);
+                utf8_bytes[2] = 0x80 | (wc & 0x3F);
+                utf8_bytes_filled = 3;
+            }
+            else if (wc <= 0x10FFFF)
+            {
+                utf8_bytes[0] = 0xF0 | ((wc >> 18) & 0x07);
+                utf8_bytes[1] = 0x80 | ((wc >> 12) & 0x3F);
+                utf8_bytes[2] = 0x80 | ((wc >> 6) & 0x3F);
+                utf8_bytes[3] = 0x80 | (wc & 0x3F);
+                utf8_bytes_filled = 4;
             }
             else
             {
-                fill_buffer_utf32();
+                // unknown character
+                utf8_bytes[0] = wc;
+                utf8_bytes_filled = 1;
             }
-
-            assert(utf8_bytes_filled > 0);
-            assert(utf8_bytes_index == 0);
         }
-
-        // use buffer
-        assert(utf8_bytes_filled > 0);
-        assert(utf8_bytes_index < utf8_bytes_filled);
-        return utf8_bytes[utf8_bytes_index++];
     }
+};
 
-  private:
-    void fill_buffer_utf16()
+template<typename WideStringType>
+struct wide_string_input_helper<WideStringType, 2>
+{
+    // UTF-16
+    static void fill_buffer(const WideStringType& str, size_t& current_wchar, std::array<std::char_traits<char>::int_type, 4>& utf8_bytes, size_t& utf8_bytes_index, size_t& utf8_bytes_filled)
     {
         utf8_bytes_index = 0;
 
@@ -158,7 +197,7 @@ class wide_string_input_adapter : public input_adapter_protocol
         else
         {
             // get the current character
-            const int wc = static_cast<int>(str[current_wchar++]);
+            const auto wc = static_cast<int>(str[current_wchar++]);
 
             // UTF-16 to UTF-8 encoding
             if (wc < 0x80)
@@ -183,7 +222,7 @@ class wide_string_input_adapter : public input_adapter_protocol
             {
                 if (current_wchar < str.size())
                 {
-                    const int wc2 = static_cast<int>(str[current_wchar++]);
+                    const auto wc2 = static_cast<int>(str[current_wchar++]);
                     const int charcode = 0x10000 + (((wc & 0x3FF) << 10) | (wc2 & 0x3FF));
                     utf8_bytes[0] = 0xf0 | (charcode >> 18);
                     utf8_bytes[1] = 0x80 | ((charcode >> 12) & 0x3F);
@@ -201,58 +240,40 @@ class wide_string_input_adapter : public input_adapter_protocol
             }
         }
     }
+};
 
-    void fill_buffer_utf32()
-    {
-        utf8_bytes_index = 0;
+template<typename WideStringType>
+class wide_string_input_adapter : public input_adapter_protocol
+{
+  public:
+    explicit wide_string_input_adapter(const WideStringType& w)  noexcept
+        : str(w)
+    {}
 
-        if (current_wchar == str.size())
-        {
-            utf8_bytes[0] = std::char_traits<char>::eof();
-            utf8_bytes_filled = 1;
-        }
-        else
+    std::char_traits<char>::int_type get_character() noexcept override
+    {
+        // check if buffer needs to be filled
+        if (utf8_bytes_index == utf8_bytes_filled)
         {
-            // get the current character
-            const int wc = static_cast<int>(str[current_wchar++]);
+            fill_buffer<sizeof(typename WideStringType::value_type)>();
 
-            // UTF-32 to UTF-8 encoding
-            if (wc < 0x80)
-            {
-                utf8_bytes[0] = wc;
-                utf8_bytes_filled = 1;
-            }
-            else if (wc <= 0x7FF)
-            {
-                utf8_bytes[0] = 0xC0 | ((wc >> 6) & 0x1F);
-                utf8_bytes[1] = 0x80 | (wc & 0x3F);
-                utf8_bytes_filled = 2;
-            }
-            else if (wc <= 0xFFFF)
-            {
-                utf8_bytes[0] = 0xE0 | ((wc >> 12) & 0x0F);
-                utf8_bytes[1] = 0x80 | ((wc >> 6) & 0x3F);
-                utf8_bytes[2] = 0x80 | (wc & 0x3F);
-                utf8_bytes_filled = 3;
-            }
-            else if (wc <= 0x10FFFF)
-            {
-                utf8_bytes[0] = 0xF0 | ((wc >> 18 ) & 0x07);
-                utf8_bytes[1] = 0x80 | ((wc >> 12) & 0x3F);
-                utf8_bytes[2] = 0x80 | ((wc >> 6) & 0x3F);
-                utf8_bytes[3] = 0x80 | (wc & 0x3F);
-                utf8_bytes_filled = 4;
-            }
-            else
-            {
-                // unknown character
-                utf8_bytes[0] = wc;
-                utf8_bytes_filled = 1;
-            }
+            assert(utf8_bytes_filled > 0);
+            assert(utf8_bytes_index == 0);
         }
+
+        // use buffer
+        assert(utf8_bytes_filled > 0);
+        assert(utf8_bytes_index < utf8_bytes_filled);
+        return utf8_bytes[utf8_bytes_index++];
     }
 
   private:
+    template<size_t T>
+    void fill_buffer()
+    {
+        wide_string_input_helper<WideStringType, T>::fill_buffer(str, current_wchar, utf8_bytes, utf8_bytes_index, utf8_bytes_filled);
+    }
+
     /// the wstring to process
     const WideStringType& str;
 
@@ -373,5 +394,5 @@ class input_adapter
     /// the actual adapter
     input_adapter_t ia = nullptr;
 };
-}
-}
+}  // namespace detail
+}  // namespace nlohmann
diff --git a/include/lib/modernjson/detail/input/json_sax.hpp b/include/lib/modernjson/detail/input/json_sax.hpp
index 968fcd0..e1d48a2 100644
--- a/include/lib/modernjson/detail/input/json_sax.hpp
+++ b/include/lib/modernjson/detail/input/json_sax.hpp
@@ -113,7 +113,7 @@ struct json_sax
     @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] error_msg   a detailed error message
+    @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,
@@ -181,7 +181,7 @@ class json_sax_dom_parser
         return true;
     }
 
-    bool number_float(number_float_t val, const string_t&)
+    bool number_float(number_float_t val, const string_t& /*unused*/)
     {
         handle_value(val);
         return true;
@@ -238,7 +238,7 @@ class json_sax_dom_parser
         return true;
     }
 
-    bool parse_error(std::size_t, const std::string&,
+    bool parse_error(std::size_t /*unused*/, const std::string& /*unused*/,
                      const detail::exception& ex)
     {
         errored = true;
@@ -286,20 +286,19 @@ class json_sax_dom_parser
             root = BasicJsonType(std::forward<Value>(v));
             return &root;
         }
+
+        assert(ref_stack.back()->is_array() or ref_stack.back()->is_object());
+
+        if (ref_stack.back()->is_array())
+        {
+            ref_stack.back()->m_value.array->emplace_back(std::forward<Value>(v));
+            return &(ref_stack.back()->m_value.array->back());
+        }
         else
         {
-            assert(ref_stack.back()->is_array() or ref_stack.back()->is_object());
-            if (ref_stack.back()->is_array())
-            {
-                ref_stack.back()->m_value.array->emplace_back(std::forward<Value>(v));
-                return &(ref_stack.back()->m_value.array->back());
-            }
-            else
-            {
-                assert(object_element);
-                *object_element = BasicJsonType(std::forward<Value>(v));
-                return object_element;
-            }
+            assert(object_element);
+            *object_element = BasicJsonType(std::forward<Value>(v));
+            return object_element;
         }
     }
 
@@ -358,7 +357,7 @@ class json_sax_dom_callback_parser
         return true;
     }
 
-    bool number_float(number_float_t val, const string_t&)
+    bool number_float(number_float_t val, const string_t& /*unused*/)
     {
         handle_value(val);
         return true;
@@ -496,7 +495,7 @@ class json_sax_dom_callback_parser
         return true;
     }
 
-    bool parse_error(std::size_t, const std::string&,
+    bool parse_error(std::size_t /*unused*/, const std::string& /*unused*/,
                      const detail::exception& ex)
     {
         errored = true;
@@ -574,37 +573,37 @@ class json_sax_dom_callback_parser
             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 (not ref_stack.back())
+        {
+            return {false, nullptr};
+        }
+
+        // we now only expect arrays and objects
+        assert(ref_stack.back()->is_array() or ref_stack.back()->is_object());
+
+        if (ref_stack.back()->is_array())
+        {
+            ref_stack.back()->m_value.array->push_back(std::move(value));
+            return {true, &(ref_stack.back()->m_value.array->back())};
+        }
         else
         {
-            // skip this value if we already decided to skip the parent
-            // (https://github.com/nlohmann/json/issues/971#issuecomment-413678360)
-            if (not ref_stack.back())
-            {
-                return {false, nullptr};
-            }
+            // check if we should store an element for the current key
+            assert(not key_keep_stack.empty());
+            const bool store_element = key_keep_stack.back();
+            key_keep_stack.pop_back();
 
-            assert(ref_stack.back()->is_array() or ref_stack.back()->is_object());
-            if (ref_stack.back()->is_array())
+            if (not store_element)
             {
-                ref_stack.back()->m_value.array->push_back(std::move(value));
-                return {true, &(ref_stack.back()->m_value.array->back())};
+                return {false, nullptr};
             }
-            else
-            {
-                // check if we should store an element for the current key
-                assert(not key_keep_stack.empty());
-                const bool store_element = key_keep_stack.back();
-                key_keep_stack.pop_back();
-
-                if (not store_element)
-                {
-                    return {false, nullptr};
-                }
 
-                assert(object_element);
-                *object_element = std::move(value);
-                return {true, object_element};
-            }
+            assert(object_element);
+            *object_element = std::move(value);
+            return {true, object_element};
         }
     }
 
@@ -642,37 +641,37 @@ class json_sax_acceptor
         return true;
     }
 
-    bool boolean(bool)
+    bool boolean(bool /*unused*/)
     {
         return true;
     }
 
-    bool number_integer(number_integer_t)
+    bool number_integer(number_integer_t /*unused*/)
     {
         return true;
     }
 
-    bool number_unsigned(number_unsigned_t)
+    bool number_unsigned(number_unsigned_t /*unused*/)
     {
         return true;
     }
 
-    bool number_float(number_float_t, const string_t&)
+    bool number_float(number_float_t /*unused*/, const string_t& /*unused*/)
     {
         return true;
     }
 
-    bool string(string_t&)
+    bool string(string_t& /*unused*/)
     {
         return true;
     }
 
-    bool start_object(std::size_t = std::size_t(-1))
+    bool start_object(std::size_t  /*unused*/ = std::size_t(-1))
     {
         return true;
     }
 
-    bool key(string_t&)
+    bool key(string_t& /*unused*/)
     {
         return true;
     }
@@ -682,7 +681,7 @@ class json_sax_acceptor
         return true;
     }
 
-    bool start_array(std::size_t = std::size_t(-1))
+    bool start_array(std::size_t  /*unused*/ = std::size_t(-1))
     {
         return true;
     }
@@ -692,11 +691,11 @@ class json_sax_acceptor
         return true;
     }
 
-    bool parse_error(std::size_t, const std::string&, const detail::exception&)
+    bool parse_error(std::size_t /*unused*/, const std::string& /*unused*/, const detail::exception& /*unused*/)
     {
         return false;
     }
 };
-}
+}  // namespace detail
 
-}
+}  // namespace nlohmann
diff --git a/include/lib/modernjson/detail/input/lexer.hpp b/include/lib/modernjson/detail/input/lexer.hpp
index 9606211..b61e289 100644
--- a/include/lib/modernjson/detail/input/lexer.hpp
+++ b/include/lib/modernjson/detail/input/lexer.hpp
@@ -10,6 +10,7 @@
 
 #include <lib/modernjson/detail/macro_scope.hpp>
 #include <lib/modernjson/detail/input/input_adapters.hpp>
+#include <lib/modernjson/detail/input/position_t.hpp>
 
 namespace nlohmann
 {
@@ -104,7 +105,10 @@ class lexer
 
     // delete because of pointer members
     lexer(const lexer&) = delete;
+    lexer(lexer&&) = delete;
     lexer& operator=(lexer&) = delete;
+    lexer& operator=(lexer&&) = delete;
+    ~lexer() = default;
 
   private:
     /////////////////////
@@ -393,39 +397,194 @@ class lexer
 
                 // invalid control characters
                 case 0x00:
+                {
+                    error_message = "invalid string: control character U+0000 (NUL) must be escaped to \\u0000";
+                    return token_type::parse_error;
+                }
+
                 case 0x01:
+                {
+                    error_message = "invalid string: control character U+0001 (SOH) must be escaped to \\u0001";
+                    return token_type::parse_error;
+                }
+
                 case 0x02:
+                {
+                    error_message = "invalid string: control character U+0002 (STX) must be escaped to \\u0002";
+                    return token_type::parse_error;
+                }
+
                 case 0x03:
+                {
+                    error_message = "invalid string: control character U+0003 (ETX) must be escaped to \\u0003";
+                    return token_type::parse_error;
+                }
+
                 case 0x04:
+                {
+                    error_message = "invalid string: control character U+0004 (EOT) must be escaped to \\u0004";
+                    return token_type::parse_error;
+                }
+
                 case 0x05:
+                {
+                    error_message = "invalid string: control character U+0005 (ENQ) must be escaped to \\u0005";
+                    return token_type::parse_error;
+                }
+
                 case 0x06:
+                {
+                    error_message = "invalid string: control character U+0006 (ACK) must be escaped to \\u0006";
+                    return token_type::parse_error;
+                }
+
                 case 0x07:
+                {
+                    error_message = "invalid string: control character U+0007 (BEL) must be escaped to \\u0007";
+                    return token_type::parse_error;
+                }
+
                 case 0x08:
+                {
+                    error_message = "invalid string: control character U+0008 (BS) must be escaped to \\u0008 or \\b";
+                    return token_type::parse_error;
+                }
+
                 case 0x09:
+                {
+                    error_message = "invalid string: control character U+0009 (HT) must be escaped to \\u0009 or \\t";
+                    return token_type::parse_error;
+                }
+
                 case 0x0A:
+                {
+                    error_message = "invalid string: control character U+000A (LF) must be escaped to \\u000A or \\n";
+                    return token_type::parse_error;
+                }
+
                 case 0x0B:
+                {
+                    error_message = "invalid string: control character U+000B (VT) must be escaped to \\u000B";
+                    return token_type::parse_error;
+                }
+
                 case 0x0C:
+                {
+                    error_message = "invalid string: control character U+000C (FF) must be escaped to \\u000C or \\f";
+                    return token_type::parse_error;
+                }
+
                 case 0x0D:
+                {
+                    error_message = "invalid string: control character U+000D (CR) must be escaped to \\u000D or \\r";
+                    return token_type::parse_error;
+                }
+
                 case 0x0E:
+                {
+                    error_message = "invalid string: control character U+000E (SO) must be escaped to \\u000E";
+                    return token_type::parse_error;
+                }
+
                 case 0x0F:
+                {
+                    error_message = "invalid string: control character U+000F (SI) must be escaped to \\u000F";
+                    return token_type::parse_error;
+                }
+
                 case 0x10:
+                {
+                    error_message = "invalid string: control character U+0010 (DLE) must be escaped to \\u0010";
+                    return token_type::parse_error;
+                }
+
                 case 0x11:
+                {
+                    error_message = "invalid string: control character U+0011 (DC1) must be escaped to \\u0011";
+                    return token_type::parse_error;
+                }
+
                 case 0x12:
+                {
+                    error_message = "invalid string: control character U+0012 (DC2) must be escaped to \\u0012";
+                    return token_type::parse_error;
+                }
+
                 case 0x13:
+                {
+                    error_message = "invalid string: control character U+0013 (DC3) must be escaped to \\u0013";
+                    return token_type::parse_error;
+                }
+
                 case 0x14:
+                {
+                    error_message = "invalid string: control character U+0014 (DC4) must be escaped to \\u0014";
+                    return token_type::parse_error;
+                }
+
                 case 0x15:
+                {
+                    error_message = "invalid string: control character U+0015 (NAK) must be escaped to \\u0015";
+                    return token_type::parse_error;
+                }
+
                 case 0x16:
+                {
+                    error_message = "invalid string: control character U+0016 (SYN) must be escaped to \\u0016";
+                    return token_type::parse_error;
+                }
+
                 case 0x17:
+                {
+                    error_message = "invalid string: control character U+0017 (ETB) must be escaped to \\u0017";
+                    return token_type::parse_error;
+                }
+
                 case 0x18:
+                {
+                    error_message = "invalid string: control character U+0018 (CAN) must be escaped to \\u0018";
+                    return token_type::parse_error;
+                }
+
                 case 0x19:
+                {
+                    error_message = "invalid string: control character U+0019 (EM) must be escaped to \\u0019";
+                    return token_type::parse_error;
+                }
+
                 case 0x1A:
+                {
+                    error_message = "invalid string: control character U+001A (SUB) must be escaped to \\u001A";
+                    return token_type::parse_error;
+                }
+
                 case 0x1B:
+                {
+                    error_message = "invalid string: control character U+001B (ESC) must be escaped to \\u001B";
+                    return token_type::parse_error;
+                }
+
                 case 0x1C:
+                {
+                    error_message = "invalid string: control character U+001C (FS) must be escaped to \\u001C";
+                    return token_type::parse_error;
+                }
+
                 case 0x1D:
+                {
+                    error_message = "invalid string: control character U+001D (GS) must be escaped to \\u001D";
+                    return token_type::parse_error;
+                }
+
                 case 0x1E:
+                {
+                    error_message = "invalid string: control character U+001E (RS) must be escaped to \\u001E";
+                    return token_type::parse_error;
+                }
+
                 case 0x1F:
                 {
-                    error_message = "invalid string: control character must be escaped";
+                    error_message = "invalid string: control character U+001F (US) must be escaped to \\u001F";
                     return token_type::parse_error;
                 }
 
@@ -709,7 +868,7 @@ class lexer
           locale's decimal point is used instead of `.` to work with the
           locale-dependent converters.
     */
-    token_type scan_number()
+    token_type scan_number()  // lgtm [cpp/use-of-goto]
     {
         // reset token_buffer to store the number's bytes
         reset();
@@ -1082,7 +1241,9 @@ scan_number_done:
     */
     std::char_traits<char>::int_type get()
     {
-        ++chars_read;
+        ++position.chars_read_total;
+        ++position.chars_read_current_line;
+
         if (next_unget)
         {
             // just reset the next_unget variable and work with current
@@ -1097,6 +1258,13 @@ scan_number_done:
         {
             token_string.push_back(std::char_traits<char>::to_char_type(current));
         }
+
+        if (current == '\n')
+        {
+            ++position.lines_read;
+            ++position.chars_read_current_line = 0;
+        }
+
         return current;
     }
 
@@ -1104,14 +1272,29 @@ scan_number_done:
     @brief unget current character (read it again on next get)
 
     We implement unget by setting variable next_unget to true. The input is not
-    changed - we just simulate ungetting by modifying chars_read and
-    token_string. The next call to get() will behave as if the unget character
-    is read again.
+    changed - we just simulate ungetting by modifying chars_read_total,
+    chars_read_current_line, and token_string. The next call to get() will
+    behave as if the unget character is read again.
     */
     void unget()
     {
         next_unget = true;
-        --chars_read;
+
+        --position.chars_read_total;
+
+        // in case we "unget" a newline, we have to also decrement the lines_read
+        if (position.chars_read_current_line == 0)
+        {
+            if (position.lines_read > 0)
+            {
+                --position.lines_read;
+            }
+        }
+        else
+        {
+            --position.chars_read_current_line;
+        }
+
         if (JSON_LIKELY(current != std::char_traits<char>::eof()))
         {
             assert(token_string.size() != 0);
@@ -1159,9 +1342,9 @@ scan_number_done:
     /////////////////////
 
     /// return position of last read token
-    constexpr std::size_t get_position() const noexcept
+    constexpr position_t get_position() const noexcept
     {
-        return chars_read;
+        return position;
     }
 
     /// return the last read token (for errors only).  Will never contain EOF
@@ -1177,7 +1360,7 @@ scan_number_done:
             {
                 // escape control characters
                 char cs[9];
-                snprintf(cs, 9, "<U+%.4X>", static_cast<unsigned char>(c));
+                (std::snprintf)(cs, 9, "<U+%.4X>", static_cast<unsigned char>(c));
                 result += cs;
             }
             else
@@ -1208,30 +1391,20 @@ scan_number_done:
     {
         if (get() == 0xEF)
         {
-            if (get() == 0xBB and get() == 0xBF)
-            {
-                // we completely parsed the BOM
-                return true;
-            }
-            else
-            {
-                // after reading 0xEF, an unexpected character followed
-                return false;
-            }
-        }
-        else
-        {
-            // the first character is not the beginning of the BOM; unget it to
-            // process is later
-            unget();
-            return true;
+            // check if we completely parse the BOM
+            return get() == 0xBB and get() == 0xBF;
         }
+
+        // the first character is not the beginning of the BOM; unget it to
+        // process is later
+        unget();
+        return true;
     }
 
     token_type scan()
     {
         // initially, skip the BOM
-        if (chars_read == 0 and not skip_bom())
+        if (position.chars_read_total == 0 and not skip_bom())
         {
             error_message = "invalid BOM; must be 0xEF 0xBB 0xBF if given";
             return token_type::parse_error;
@@ -1309,8 +1482,8 @@ scan_number_done:
     /// whether the next get() call should just return current
     bool next_unget = false;
 
-    /// the number of characters read
-    std::size_t chars_read = 0;
+    /// the start position of the current token
+    position_t position;
 
     /// raw input token string (for error messages)
     std::vector<char> token_string {};
@@ -1329,5 +1502,5 @@ scan_number_done:
     /// the decimal point
     const char decimal_point_char = '.';
 };
-}
-}
+}  // namespace detail
+}  // namespace nlohmann
diff --git a/include/lib/modernjson/detail/input/parser.hpp b/include/lib/modernjson/detail/input/parser.hpp
index a622077..d205bbb 100644
--- a/include/lib/modernjson/detail/input/parser.hpp
+++ b/include/lib/modernjson/detail/input/parser.hpp
@@ -91,7 +91,8 @@ class parser
             {
                 sdp.parse_error(m_lexer.get_position(),
                                 m_lexer.get_token_string(),
-                                parse_error::create(101, m_lexer.get_position(), exception_message(token_type::end_of_input)));
+                                parse_error::create(101, m_lexer.get_position(),
+                                                    exception_message(token_type::end_of_input, "value")));
             }
 
             // in case of an error, return discarded value
@@ -119,7 +120,8 @@ class parser
             {
                 sdp.parse_error(m_lexer.get_position(),
                                 m_lexer.get_token_string(),
-                                parse_error::create(101, m_lexer.get_position(), exception_message(token_type::end_of_input)));
+                                parse_error::create(101, m_lexer.get_position(),
+                                                    exception_message(token_type::end_of_input, "value")));
             }
 
             // in case of an error, return discarded value
@@ -154,7 +156,8 @@ class parser
         {
             return sax->parse_error(m_lexer.get_position(),
                                     m_lexer.get_token_string(),
-                                    parse_error::create(101, m_lexer.get_position(), exception_message(token_type::end_of_input)));
+                                    parse_error::create(101, m_lexer.get_position(),
+                                            exception_message(token_type::end_of_input, "value")));
         }
 
         return result;
@@ -164,7 +167,7 @@ class parser
     template <typename SAX>
     bool sax_parse_internal(SAX* sax)
     {
-        // stack to remember the hieararchy of structured values we are parsing
+        // stack to remember the hierarchy of structured values we are parsing
         // true = array; false = object
         std::vector<bool> states;
         // value to avoid a goto (see comment where set to true)
@@ -199,14 +202,12 @@ class parser
                         {
                             return sax->parse_error(m_lexer.get_position(),
                                                     m_lexer.get_token_string(),
-                                                    parse_error::create(101, m_lexer.get_position(), exception_message(token_type::value_string)));
+                                                    parse_error::create(101, m_lexer.get_position(),
+                                                            exception_message(token_type::value_string, "object key")));
                         }
-                        else
+                        if (JSON_UNLIKELY(not sax->key(m_lexer.get_string())))
                         {
-                            if (JSON_UNLIKELY(not sax->key(m_lexer.get_string())))
-                            {
-                                return false;
-                            }
+                            return false;
                         }
 
                         // parse separator (:)
@@ -214,7 +215,8 @@ class parser
                         {
                             return sax->parse_error(m_lexer.get_position(),
                                                     m_lexer.get_token_string(),
-                                                    parse_error::create(101, m_lexer.get_position(), exception_message(token_type::name_separator)));
+                                                    parse_error::create(101, m_lexer.get_position(),
+                                                            exception_message(token_type::name_separator, "object separator")));
                         }
 
                         // remember we are now inside an object
@@ -328,14 +330,16 @@ class parser
                         // using "uninitialized" to avoid "expected" message
                         return sax->parse_error(m_lexer.get_position(),
                                                 m_lexer.get_token_string(),
-                                                parse_error::create(101, m_lexer.get_position(), exception_message(token_type::uninitialized)));
+                                                parse_error::create(101, m_lexer.get_position(),
+                                                        exception_message(token_type::uninitialized, "value")));
                     }
 
                     default: // the last token was unexpected
                     {
                         return sax->parse_error(m_lexer.get_position(),
                                                 m_lexer.get_token_string(),
-                                                parse_error::create(101, m_lexer.get_position(), exception_message(token_type::literal_or_value)));
+                                                parse_error::create(101, m_lexer.get_position(),
+                                                        exception_message(token_type::literal_or_value, "value")));
                     }
                 }
             }
@@ -347,7 +351,7 @@ class parser
             // we reached this line after we successfully parsed a value
             if (states.empty())
             {
-                // empty stack: we reached the end of the hieararchy: done
+                // empty stack: we reached the end of the hierarchy: done
                 return true;
             }
             else
@@ -383,7 +387,8 @@ class parser
                     {
                         return sax->parse_error(m_lexer.get_position(),
                                                 m_lexer.get_token_string(),
-                                                parse_error::create(101, m_lexer.get_position(), exception_message(token_type::end_array)));
+                                                parse_error::create(101, m_lexer.get_position(),
+                                                        exception_message(token_type::end_array, "array")));
                     }
                 }
                 else  // object
@@ -396,7 +401,8 @@ class parser
                         {
                             return sax->parse_error(m_lexer.get_position(),
                                                     m_lexer.get_token_string(),
-                                                    parse_error::create(101, m_lexer.get_position(), exception_message(token_type::value_string)));
+                                                    parse_error::create(101, m_lexer.get_position(),
+                                                            exception_message(token_type::value_string, "object key")));
                         }
                         else
                         {
@@ -411,7 +417,8 @@ class parser
                         {
                             return sax->parse_error(m_lexer.get_position(),
                                                     m_lexer.get_token_string(),
-                                                    parse_error::create(101, m_lexer.get_position(), exception_message(token_type::name_separator)));
+                                                    parse_error::create(101, m_lexer.get_position(),
+                                                            exception_message(token_type::name_separator, "object separator")));
                         }
 
                         // parse values
@@ -440,7 +447,8 @@ class parser
                     {
                         return sax->parse_error(m_lexer.get_position(),
                                                 m_lexer.get_token_string(),
-                                                parse_error::create(101, m_lexer.get_position(), exception_message(token_type::end_object)));
+                                                parse_error::create(101, m_lexer.get_position(),
+                                                        exception_message(token_type::end_object, "object")));
                     }
                 }
             }
@@ -453,9 +461,17 @@ class parser
         return (last_token = m_lexer.scan());
     }
 
-    std::string exception_message(const token_type expected)
+    std::string exception_message(const token_type expected, const std::string& context)
     {
-        std::string error_msg = "syntax error - ";
+        std::string error_msg = "syntax error ";
+
+        if (not context.empty())
+        {
+            error_msg += "while parsing " + context + " ";
+        }
+
+        error_msg += "- ";
+
         if (last_token == token_type::parse_error)
         {
             error_msg += std::string(m_lexer.get_error_message()) + "; last read: '" +
@@ -484,5 +500,5 @@ class parser
     /// whether to throw exceptions in case of errors
     const bool allow_exceptions = true;
 };
-}
-}
+}  // namespace detail
+}  // namespace nlohmann
diff --git a/include/lib/modernjson/detail/input/position_t.hpp b/include/lib/modernjson/detail/input/position_t.hpp
new file mode 100644
index 0000000..37f4ab1
--- /dev/null
+++ b/include/lib/modernjson/detail/input/position_t.hpp
@@ -0,0 +1,27 @@
+#pragma once
+
+#include <cstddef> // size_t
+
+namespace nlohmann
+{
+namespace detail
+{
+/// struct to capture the start position of the current token
+struct position_t
+{
+    /// the total number of characters read
+    std::size_t chars_read_total = 0;
+    /// the number of characters read in the current line
+    std::size_t chars_read_current_line = 0;
+    /// the number of lines read
+    std::size_t lines_read = 0;
+
+    /// conversion to size_t to preserve SAX interface
+    constexpr operator size_t() const
+    {
+        return chars_read_total;
+    }
+};
+
+}
+}