Merge branch 'develop' of https://github.com/nlohmann/json into bon8

Conflicts: docs/examples/to_bon8.cpp docs/examples/to_bon8.output docs/mkdocs/docs/api/basic_json/to_bon8.md include/nlohmann/detail/input/binary_reader.hpp include/nlohmann/detail/input/input_adapters.hpp include/nlohmann/detail/output/binary_writer.hpp single_include/nlohmann/json.hpp test/CMakeLists.txt tests/src/unit-binary_formats.cpp tests/src/unit-bon8.cpp
2026-09-06 00:08:00 +00:00 · 2022-05-01 18:46:44 +02:00
parent 9105f5514e 0c698b75cc
commit 88fbbd3aa8
925 changed files with 15696 additions and 7756 deletions
@@ -2,16 +2,19 @@

 #include <algorithm> // reverse
 #include <array> // array
+#include <map> // map
 #include <cmath> // isnan, isinf
 #include <cstdint> // uint8_t, uint16_t, uint32_t, uint64_t
 #include <cstring> // memcpy
 #include <limits> // numeric_limits
 #include <string> // string
 #include <utility> // move
+#include <vector> // vector

 #include <nlohmann/detail/input/binary_reader.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
 #include <nlohmann/detail/output/output_adapters.hpp>
+#include <nlohmann/detail/string_concat.hpp>

 namespace nlohmann
 {
@@ -67,7 +70,7 @@ class binary_writer
            case value_t::discarded:
            default:
            {
-                JSON_THROW(type_error::create(317, "to serialize to BSON, top-level type must be object, but is " + std::string(j.type_name()), j));
+                JSON_THROW(type_error::create(317, concat("to serialize to BSON, top-level type must be object, but is ", j.type_name()), &j));
            }
        }
    }
@@ -723,9 +726,11 @@ class binary_writer
    @param[in] use_count   whether to use '#' prefixes (optimized format)
    @param[in] use_type    whether to use '$' prefixes (optimized format)
    @param[in] add_prefix  whether prefixes need to be used for this value
+    @param[in] use_bjdata  whether write in BJData format, default is false
    */
    void write_ubjson(const BasicJsonType& j, const bool use_count,
-                      const bool use_type, const bool add_prefix = true)
+                      const bool use_type, const bool add_prefix = true,
+                      const bool use_bjdata = false)
    {
        switch (j.type())
        {
@@ -751,19 +756,19 @@ class binary_writer

            case value_t::number_integer:
            {
-                write_number_with_ubjson_prefix(j.m_value.number_integer, add_prefix);
+                write_number_with_ubjson_prefix(j.m_value.number_integer, add_prefix, use_bjdata);
                break;
            }

            case value_t::number_unsigned:
            {
-                write_number_with_ubjson_prefix(j.m_value.number_unsigned, add_prefix);
+                write_number_with_ubjson_prefix(j.m_value.number_unsigned, add_prefix, use_bjdata);
                break;
            }

            case value_t::number_float:
            {
-                write_number_with_ubjson_prefix(j.m_value.number_float, add_prefix);
+                write_number_with_ubjson_prefix(j.m_value.number_float, add_prefix, use_bjdata);
                break;
            }

@@ -773,7 +778,7 @@ class binary_writer
                {
                    oa->write_character(to_char_type('S'));
                }
-                write_number_with_ubjson_prefix(j.m_value.string->size(), true);
+                write_number_with_ubjson_prefix(j.m_value.string->size(), true, use_bjdata);
                oa->write_characters(
                    reinterpret_cast<const CharType*>(j.m_value.string->c_str()),
                    j.m_value.string->size());
@@ -791,14 +796,16 @@ class binary_writer
                if (use_type && !j.m_value.array->empty())
                {
                    JSON_ASSERT(use_count);
-                    const CharType first_prefix = ubjson_prefix(j.front());
+                    const CharType first_prefix = ubjson_prefix(j.front(), use_bjdata);
                    const bool same_prefix = std::all_of(j.begin() + 1, j.end(),
-                                                         [this, first_prefix](const BasicJsonType & v)
+                                                         [this, first_prefix, use_bjdata](const BasicJsonType & v)
                    {
-                        return ubjson_prefix(v) == first_prefix;
+                        return ubjson_prefix(v, use_bjdata) == first_prefix;
                    });

-                    if (same_prefix)
+                    std::vector<CharType> bjdx = {'[', '{', 'S', 'H', 'T', 'F', 'N', 'Z'}; // excluded markers in bjdata optimized type
+
+                    if (same_prefix && !(use_bjdata && std::find(bjdx.begin(), bjdx.end(), first_prefix) != bjdx.end()))
                    {
                        prefix_required = false;
                        oa->write_character(to_char_type('$'));
@@ -809,12 +816,12 @@ class binary_writer
                if (use_count)
                {
                    oa->write_character(to_char_type('#'));
-                    write_number_with_ubjson_prefix(j.m_value.array->size(), true);
+                    write_number_with_ubjson_prefix(j.m_value.array->size(), true, use_bjdata);
                }

                for (const auto& el : *j.m_value.array)
                {
-                    write_ubjson(el, use_count, use_type, prefix_required);
+                    write_ubjson(el, use_count, use_type, prefix_required, use_bjdata);
                }

                if (!use_count)
@@ -842,7 +849,7 @@ class binary_writer
                if (use_count)
                {
                    oa->write_character(to_char_type('#'));
-                    write_number_with_ubjson_prefix(j.m_value.binary->size(), true);
+                    write_number_with_ubjson_prefix(j.m_value.binary->size(), true, use_bjdata);
                }

                if (use_type)
@@ -870,6 +877,14 @@ class binary_writer

            case value_t::object:
            {
+                if (use_bjdata && j.m_value.object->size() == 3 && j.m_value.object->find("_ArrayType_") != j.m_value.object->end() && j.m_value.object->find("_ArraySize_") != j.m_value.object->end() && j.m_value.object->find("_ArrayData_") != j.m_value.object->end())
+                {
+                    if (!write_bjdata_ndarray(*j.m_value.object, use_count, use_type))  // decode bjdata ndarray in the JData format (https://github.com/NeuroJSON/jdata)
+                    {
+                        break;
+                    }
+                }
+
                if (add_prefix)
                {
                    oa->write_character(to_char_type('{'));
@@ -879,14 +894,16 @@ class binary_writer
                if (use_type && !j.m_value.object->empty())
                {
                    JSON_ASSERT(use_count);
-                    const CharType first_prefix = ubjson_prefix(j.front());
+                    const CharType first_prefix = ubjson_prefix(j.front(), use_bjdata);
                    const bool same_prefix = std::all_of(j.begin(), j.end(),
-                                                         [this, first_prefix](const BasicJsonType & v)
+                                                         [this, first_prefix, use_bjdata](const BasicJsonType & v)
                    {
-                        return ubjson_prefix(v) == first_prefix;
+                        return ubjson_prefix(v, use_bjdata) == first_prefix;
                    });

-                    if (same_prefix)
+                    std::vector<CharType> bjdx = {'[', '{', 'S', 'H', 'T', 'F', 'N', 'Z'}; // excluded markers in bjdata optimized type
+
+                    if (same_prefix && !(use_bjdata && std::find(bjdx.begin(), bjdx.end(), first_prefix) != bjdx.end()))
                    {
                        prefix_required = false;
                        oa->write_character(to_char_type('$'));
@@ -897,16 +914,16 @@ class binary_writer
                if (use_count)
                {
                    oa->write_character(to_char_type('#'));
-                    write_number_with_ubjson_prefix(j.m_value.object->size(), true);
+                    write_number_with_ubjson_prefix(j.m_value.object->size(), true, use_bjdata);
                }

                for (const auto& el : *j.m_value.object)
                {
-                    write_number_with_ubjson_prefix(el.first.size(), true);
+                    write_number_with_ubjson_prefix(el.first.size(), true, use_bjdata);
                    oa->write_characters(
                        reinterpret_cast<const CharType*>(el.first.c_str()),
                        el.first.size());
-                    write_ubjson(el.second, use_count, use_type, prefix_required);
+                    write_ubjson(el.second, use_count, use_type, prefix_required, use_bjdata);
                }

                if (!use_count)
@@ -949,7 +966,7 @@ class binary_writer
        const auto it = name.find(static_cast<typename string_t::value_type>(0));
        if (JSON_HEDLEY_UNLIKELY(it != BasicJsonType::string_t::npos))
        {
-            JSON_THROW(out_of_range::create(409, "BSON key cannot contain code point U+0000 (at byte " + std::to_string(it) + ")", j));
+            JSON_THROW(out_of_range::create(409, concat("BSON key cannot contain code point U+0000 (at byte ", std::to_string(it), ")"), &j));
            static_cast<void>(j);
        }

@@ -985,7 +1002,7 @@ class binary_writer
                           const double value)
    {
        write_bson_entry_header(name, 0x01);
-        write_number<double, true>(value);
+        write_number<double>(value, true);
    }

    /*!
@@ -1004,7 +1021,7 @@ class binary_writer
    {
        write_bson_entry_header(name, 0x02);

-        write_number<std::int32_t, true>(static_cast<std::int32_t>(value.size() + 1ul));
+        write_number<std::int32_t>(static_cast<std::int32_t>(value.size() + 1ul), true);
        oa->write_characters(
            reinterpret_cast<const CharType*>(value.c_str()),
            value.size() + 1);
@@ -1037,12 +1054,12 @@ class binary_writer
        if ((std::numeric_limits<std::int32_t>::min)() <= value && value <= (std::numeric_limits<std::int32_t>::max)())
        {
            write_bson_entry_header(name, 0x10); // int32
-            write_number<std::int32_t, true>(static_cast<std::int32_t>(value));
+            write_number<std::int32_t>(static_cast<std::int32_t>(value), true);
        }
        else
        {
            write_bson_entry_header(name, 0x12); // int64
-            write_number<std::int64_t, true>(static_cast<std::int64_t>(value));
+            write_number<std::int64_t>(static_cast<std::int64_t>(value), true);
        }
    }

@@ -1065,16 +1082,16 @@ class binary_writer
        if (j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::int32_t>::max)()))
        {
            write_bson_entry_header(name, 0x10 /* int32 */);
-            write_number<std::int32_t, true>(static_cast<std::int32_t>(j.m_value.number_unsigned));
+            write_number<std::int32_t>(static_cast<std::int32_t>(j.m_value.number_unsigned), true);
        }
        else if (j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::int64_t>::max)()))
        {
            write_bson_entry_header(name, 0x12 /* int64 */);
-            write_number<std::int64_t, true>(static_cast<std::int64_t>(j.m_value.number_unsigned));
+            write_number<std::int64_t>(static_cast<std::int64_t>(j.m_value.number_unsigned), true);
        }
        else
        {
-            JSON_THROW(out_of_range::create(407, "integer number " + std::to_string(j.m_value.number_unsigned) + " cannot be represented by BSON as it does not fit int64", j));
+            JSON_THROW(out_of_range::create(407, concat("integer number ", std::to_string(j.m_value.number_unsigned), " cannot be represented by BSON as it does not fit int64"), &j));
        }
    }

@@ -1118,7 +1135,7 @@ class binary_writer
                          const typename BasicJsonType::array_t& value)
    {
        write_bson_entry_header(name, 0x04); // array
-        write_number<std::int32_t, true>(static_cast<std::int32_t>(calc_bson_array_size(value)));
+        write_number<std::int32_t>(static_cast<std::int32_t>(calc_bson_array_size(value)), true);

        std::size_t array_index = 0ul;

@@ -1138,7 +1155,7 @@ class binary_writer
    {
        write_bson_entry_header(name, 0x05);

-        write_number<std::int32_t, true>(static_cast<std::int32_t>(value.size()));
+        write_number<std::int32_t>(static_cast<std::int32_t>(value.size()), true);
        write_number(value.has_subtype() ? static_cast<std::uint8_t>(value.subtype()) : static_cast<std::uint8_t>(0x00));

        oa->write_characters(reinterpret_cast<const CharType*>(value.data()), value.size());
@@ -1260,7 +1277,7 @@ class binary_writer
    */
    void write_bson_object(const typename BasicJsonType::object_t& value)
    {
-        write_number<std::int32_t, true>(static_cast<std::int32_t>(calc_bson_object_size(value)));
+        write_number<std::int32_t>(static_cast<std::int32_t>(calc_bson_object_size(value)), true);

        for (const auto& el : value)
        {
@@ -1306,20 +1323,22 @@ class binary_writer
    template<typename NumberType, typename std::enable_if<
                 std::is_floating_point<NumberType>::value, int>::type = 0>
    void write_number_with_ubjson_prefix(const NumberType n,
-                                         const bool add_prefix)
+                                         const bool add_prefix,
+                                         const bool use_bjdata)
    {
        if (add_prefix)
        {
            oa->write_character(get_ubjson_float_prefix(n));
        }
-        write_number(n);
+        write_number(n, use_bjdata);
    }

    // UBJSON: write number (unsigned integer)
    template<typename NumberType, typename std::enable_if<
                 std::is_unsigned<NumberType>::value, int>::type = 0>
    void write_number_with_ubjson_prefix(const NumberType n,
-                                         const bool add_prefix)
+                                         const bool add_prefix,
+                                         const bool use_bjdata)
    {
        if (n <= static_cast<std::uint64_t>((std::numeric_limits<std::int8_t>::max)()))
        {
@@ -1327,7 +1346,7 @@ class binary_writer
            {
                oa->write_character(to_char_type('i'));  // int8
            }
-            write_number(static_cast<std::uint8_t>(n));
+            write_number(static_cast<std::uint8_t>(n), use_bjdata);
        }
        else if (n <= (std::numeric_limits<std::uint8_t>::max)())
        {
@@ -1335,7 +1354,7 @@ class binary_writer
            {
                oa->write_character(to_char_type('U'));  // uint8
            }
-            write_number(static_cast<std::uint8_t>(n));
+            write_number(static_cast<std::uint8_t>(n), use_bjdata);
        }
        else if (n <= static_cast<std::uint64_t>((std::numeric_limits<std::int16_t>::max)()))
        {
@@ -1343,7 +1362,15 @@ class binary_writer
            {
                oa->write_character(to_char_type('I'));  // int16
            }
-            write_number(static_cast<std::int16_t>(n));
+            write_number(static_cast<std::int16_t>(n), use_bjdata);
+        }
+        else if (use_bjdata && n <= static_cast<uint64_t>((std::numeric_limits<uint16_t>::max)()))
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('u'));  // uint16 - bjdata only
+            }
+            write_number(static_cast<std::uint16_t>(n), use_bjdata);
        }
        else if (n <= static_cast<std::uint64_t>((std::numeric_limits<std::int32_t>::max)()))
        {
@@ -1351,7 +1378,15 @@ class binary_writer
            {
                oa->write_character(to_char_type('l'));  // int32
            }
-            write_number(static_cast<std::int32_t>(n));
+            write_number(static_cast<std::int32_t>(n), use_bjdata);
+        }
+        else if (use_bjdata && n <= static_cast<uint64_t>((std::numeric_limits<uint32_t>::max)()))
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('m'));  // uint32 - bjdata only
+            }
+            write_number(static_cast<std::uint32_t>(n), use_bjdata);
        }
        else if (n <= static_cast<std::uint64_t>((std::numeric_limits<std::int64_t>::max)()))
        {
@@ -1359,7 +1394,15 @@ class binary_writer
            {
                oa->write_character(to_char_type('L'));  // int64
            }
-            write_number(static_cast<std::int64_t>(n));
+            write_number(static_cast<std::int64_t>(n), use_bjdata);
+        }
+        else if (use_bjdata && n <= (std::numeric_limits<uint64_t>::max)())
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('M'));  // uint64 - bjdata only
+            }
+            write_number(static_cast<std::uint64_t>(n), use_bjdata);
        }
        else
        {
@@ -1369,7 +1412,7 @@ class binary_writer
            }

            const auto number = BasicJsonType(n).dump();
-            write_number_with_ubjson_prefix(number.size(), true);
+            write_number_with_ubjson_prefix(number.size(), true, use_bjdata);
            for (std::size_t i = 0; i < number.size(); ++i)
            {
                oa->write_character(to_char_type(static_cast<std::uint8_t>(number[i])));
@@ -1382,7 +1425,8 @@ class binary_writer
                   std::is_signed<NumberType>::value&&
                   !std::is_floating_point<NumberType>::value, int >::type = 0 >
    void write_number_with_ubjson_prefix(const NumberType n,
-                                         const bool add_prefix)
+                                         const bool add_prefix,
+                                         const bool use_bjdata)
    {
        if ((std::numeric_limits<std::int8_t>::min)() <= n && n <= (std::numeric_limits<std::int8_t>::max)())
        {
@@ -1390,7 +1434,7 @@ class binary_writer
            {
                oa->write_character(to_char_type('i'));  // int8
            }
-            write_number(static_cast<std::int8_t>(n));
+            write_number(static_cast<std::int8_t>(n), use_bjdata);
        }
        else if (static_cast<std::int64_t>((std::numeric_limits<std::uint8_t>::min)()) <= n && n <= static_cast<std::int64_t>((std::numeric_limits<std::uint8_t>::max)()))
        {
@@ -1398,7 +1442,7 @@ class binary_writer
            {
                oa->write_character(to_char_type('U'));  // uint8
            }
-            write_number(static_cast<std::uint8_t>(n));
+            write_number(static_cast<std::uint8_t>(n), use_bjdata);
        }
        else if ((std::numeric_limits<std::int16_t>::min)() <= n && n <= (std::numeric_limits<std::int16_t>::max)())
        {
@@ -1406,7 +1450,15 @@ class binary_writer
            {
                oa->write_character(to_char_type('I'));  // int16
            }
-            write_number(static_cast<std::int16_t>(n));
+            write_number(static_cast<std::int16_t>(n), use_bjdata);
+        }
+        else if (use_bjdata && (static_cast<std::int64_t>((std::numeric_limits<std::uint16_t>::min)()) <= n && n <= static_cast<std::int64_t>((std::numeric_limits<std::uint16_t>::max)())))
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('u'));  // uint16 - bjdata only
+            }
+            write_number(static_cast<uint16_t>(n), use_bjdata);
        }
        else if ((std::numeric_limits<std::int32_t>::min)() <= n && n <= (std::numeric_limits<std::int32_t>::max)())
        {
@@ -1414,7 +1466,15 @@ class binary_writer
            {
                oa->write_character(to_char_type('l'));  // int32
            }
-            write_number(static_cast<std::int32_t>(n));
+            write_number(static_cast<std::int32_t>(n), use_bjdata);
+        }
+        else if (use_bjdata && (static_cast<std::int64_t>((std::numeric_limits<std::uint32_t>::min)()) <= n && n <= static_cast<std::int64_t>((std::numeric_limits<std::uint32_t>::max)())))
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('m'));  // uint32 - bjdata only
+            }
+            write_number(static_cast<uint32_t>(n), use_bjdata);
        }
        else if ((std::numeric_limits<std::int64_t>::min)() <= n && n <= (std::numeric_limits<std::int64_t>::max)())
        {
@@ -1422,7 +1482,7 @@ class binary_writer
            {
                oa->write_character(to_char_type('L'));  // int64
            }
-            write_number(static_cast<std::int64_t>(n));
+            write_number(static_cast<std::int64_t>(n), use_bjdata);
        }
        // LCOV_EXCL_START
        else
@@ -1433,7 +1493,7 @@ class binary_writer
            }

            const auto number = BasicJsonType(n).dump();
-            write_number_with_ubjson_prefix(number.size(), true);
+            write_number_with_ubjson_prefix(number.size(), true, use_bjdata);
            for (std::size_t i = 0; i < number.size(); ++i)
            {
                oa->write_character(to_char_type(static_cast<std::uint8_t>(number[i])));
@@ -1445,7 +1505,7 @@ class binary_writer
    /*!
    @brief determine the type prefix of container values
    */
-    CharType ubjson_prefix(const BasicJsonType& j) const noexcept
+    CharType ubjson_prefix(const BasicJsonType& j, const bool use_bjdata) const noexcept
    {
        switch (j.type())
        {
@@ -1469,10 +1529,18 @@ class binary_writer
                {
                    return 'I';
                }
+                if (use_bjdata && ((std::numeric_limits<std::uint16_t>::min)() <= j.m_value.number_integer && j.m_value.number_integer <= (std::numeric_limits<std::uint16_t>::max)()))
+                {
+                    return 'u';
+                }
                if ((std::numeric_limits<std::int32_t>::min)() <= j.m_value.number_integer && j.m_value.number_integer <= (std::numeric_limits<std::int32_t>::max)())
                {
                    return 'l';
                }
+                if (use_bjdata && ((std::numeric_limits<std::uint32_t>::min)() <= j.m_value.number_integer && j.m_value.number_integer <= (std::numeric_limits<std::uint32_t>::max)()))
+                {
+                    return 'm';
+                }
                if ((std::numeric_limits<std::int64_t>::min)() <= j.m_value.number_integer && j.m_value.number_integer <= (std::numeric_limits<std::int64_t>::max)())
                {
                    return 'L';
@@ -1495,14 +1563,26 @@ class binary_writer
                {
                    return 'I';
                }
+                if (use_bjdata && j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::uint16_t>::max)()))
+                {
+                    return 'u';
+                }
                if (j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::int32_t>::max)()))
                {
                    return 'l';
                }
+                if (use_bjdata && j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::uint32_t>::max)()))
+                {
+                    return 'm';
+                }
                if (j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::int64_t>::max)()))
                {
                    return 'L';
                }
+                if (use_bjdata && j.m_value.number_unsigned <= (std::numeric_limits<std::uint64_t>::max)())
+                {
+                    return 'M';
+                }
                // anything else is treated as high-precision number
                return 'H'; // LCOV_EXCL_LINE
            }
@@ -1536,6 +1616,118 @@ class binary_writer
        return 'D';  // float 64
    }

+    /*!
+    @return false if the object is successfully converted to a bjdata ndarray, true if the type or size is invalid
+    */
+    bool write_bjdata_ndarray(const typename BasicJsonType::object_t& value, const bool use_count, const bool use_type)
+    {
+        std::map<string_t, CharType> bjdtype = {{"uint8", 'U'},  {"int8", 'i'},  {"uint16", 'u'}, {"int16", 'I'},
+            {"uint32", 'm'}, {"int32", 'l'}, {"uint64", 'M'}, {"int64", 'L'}, {"single", 'd'}, {"double", 'D'}, {"char", 'C'}
+        };
+
+        string_t key = "_ArrayType_";
+        auto it = bjdtype.find(static_cast<string_t>(value.at(key)));
+        if (it == bjdtype.end())
+        {
+            return true;
+        }
+        CharType dtype = it->second;
+
+        key = "_ArraySize_";
+        std::size_t len = (value.at(key).empty() ? 0 : 1);
+        for (const auto& el : value.at(key))
+        {
+            len *= static_cast<std::size_t>(el.m_value.number_unsigned);
+        }
+
+        key = "_ArrayData_";
+        if (value.at(key).size() != len)
+        {
+            return true;
+        }
+
+        oa->write_character('[');
+        oa->write_character('$');
+        oa->write_character(dtype);
+        oa->write_character('#');
+
+        key = "_ArraySize_";
+        write_ubjson(value.at(key), use_count, use_type, true,  true);
+
+        key = "_ArrayData_";
+        if (dtype == 'U' || dtype == 'C')
+        {
+            for (const auto& el : value.at(key))
+            {
+                write_number(static_cast<std::uint8_t>(el.m_value.number_unsigned), true);
+            }
+        }
+        else if (dtype == 'i')
+        {
+            for (const auto& el : value.at(key))
+            {
+                write_number(static_cast<std::int8_t>(el.m_value.number_integer), true);
+            }
+        }
+        else if (dtype == 'u')
+        {
+            for (const auto& el : value.at(key))
+            {
+                write_number(static_cast<std::uint16_t>(el.m_value.number_unsigned), true);
+            }
+        }
+        else if (dtype == 'I')
+        {
+            for (const auto& el : value.at(key))
+            {
+                write_number(static_cast<std::int16_t>(el.m_value.number_integer), true);
+            }
+        }
+        else if (dtype == 'm')
+        {
+            for (const auto& el : value.at(key))
+            {
+                write_number(static_cast<std::uint32_t>(el.m_value.number_unsigned), true);
+            }
+        }
+        else if (dtype == 'l')
+        {
+            for (const auto& el : value.at(key))
+            {
+                write_number(static_cast<std::int32_t>(el.m_value.number_integer), true);
+            }
+        }
+        else if (dtype == 'M')
+        {
+            for (const auto& el : value.at(key))
+            {
+                write_number(static_cast<std::uint64_t>(el.m_value.number_unsigned), true);
+            }
+        }
+        else if (dtype == 'L')
+        {
+            for (const auto& el : value.at(key))
+            {
+                write_number(static_cast<std::int64_t>(el.m_value.number_integer), true);
+            }
+        }
+        else if (dtype == 'd')
+        {
+            for (const auto& el : value.at(key))
+            {
+                write_number(static_cast<float>(el.m_value.number_float), true);
+            }
+        }
+        else if (dtype == 'D')
+        {
+            for (const auto& el : value.at(key))
+            {
+                write_number(static_cast<double>(el.m_value.number_float), true);
+            }
+        }
+        return false;
+    }
+
    //////////
    // BON8 //
    //////////
@@ -1816,16 +2008,18 @@ class binary_writer
    /*
    @brief write a number to output input
    @param[in] n number of type @a NumberType
-    @tparam NumberType the type of the number
-    @tparam OutputIsLittleEndian Set to true if output data is
+    @param[in] OutputIsLittleEndian Set to true if output data is
                                 required to be little endian
+    @tparam NumberType the type of the number

    @note This function needs to respect the system's endianness, because bytes
          in CBOR, MessagePack, and UBJSON are stored in network order (big
          endian) and therefore need reordering on little endian systems.
+          On the other hand, BSON and BJData use little endian and should reorder
+          on big endian systems.
    */
-    template<typename NumberType, bool OutputIsLittleEndian = false>
-    void write_number(const NumberType n)
+    template<typename NumberType>
+    void write_number(const NumberType n, const bool OutputIsLittleEndian = false)
    {
        // step 1: write number to array of length NumberType
        std::array<CharType, sizeof(NumberType)> vec{};