BSON: Support for arrays

include/nlohmann/detail/input/binary_reader.hpp

@@ -157,17 +157,8 @@ class binary_reader
         return success;
     }
 
-
+    void parse_bson_entries()
-    bool parse_bson_internal()
     {
-        std::int32_t documentSize;
-        get_number_little_endian(documentSize);
-
-        if (not JSON_UNLIKELY(sax->start_object(-1)))
-        {
-            return false;
-        }
-
         while (auto entry_type = get())
         {
             switch (entry_type)
@@ -239,8 +230,46 @@ class binary_reader
                     parse_bson_internal();
                 }
                 break;
+                case 0x04: // array
+                {
+                    string_t key;
+                    get_bson_cstr(key);
+                    sax->key(key);
+                    parse_bson_array();
+                }
+                break;
             }
         }
+    }
+
+    bool parse_bson_array()
+    {
+        std::int32_t documentSize;
+        get_number_little_endian(documentSize);
+
+        if (not JSON_UNLIKELY(sax->start_array(-1)))
+        {
+            return false;
+        }
+
+        parse_bson_entries();
+
+        const auto result = sax->end_array();
+
+        return result;
+    }
+
+    bool parse_bson_internal()
+    {
+        std::int32_t documentSize;
+        get_number_little_endian(documentSize);
+
+        if (not JSON_UNLIKELY(sax->start_object(-1)))
+        {
+            return false;
+        }
+
+        parse_bson_entries();
 
         const auto result = sax->end_object();
 

include/nlohmann/detail/output/binary_writer.hpp

@@ -787,6 +787,28 @@ class binary_writer
         return /*id*/ 1ul + name.size() + 1ul + embedded_document_size;
     }
 
+    std::size_t write_bson_array(const typename BasicJsonType::string_t& name, const BasicJsonType& j)
+    {
+        oa->write_character(static_cast<CharType>(0x04)); // object
+        oa->write_characters(
+            reinterpret_cast<const CharType*>(name.c_str()),
+            name.size() + 1u);
+
+
+        auto document_size_offset = oa->reserve_characters(4ul);
+        std::int32_t embedded_document_size = 5ul;
+
+        for (const auto& el : *j.m_value.array)
+        {
+            embedded_document_size += write_bson_object_entry("", el);
+        }
+
+        oa->write_character(static_cast<CharType>(0x00));
+        write_number_little_endian_at(document_size_offset, embedded_document_size);
+
+        return /*id*/ 1ul + name.size() + 1ul + embedded_document_size;
+    }
+
     std::size_t write_bson_object_entry(const typename BasicJsonType::string_t& name, const BasicJsonType& j)
     {
         switch (j.type())
@@ -796,6 +818,8 @@ class binary_writer
                 break;
             case value_t::object:
                 return write_bson_object_internal(name, j);
+            case value_t::array:
+                return write_bson_array(name, j);
             case value_t::boolean:
                 return write_bson_boolean(name, j);
             case value_t::number_float:

single_include/nlohmann/json.hpp

@@ -6141,17 +6141,8 @@ class binary_reader
         return success;
     }
 
-
+    void parse_bson_entries()
-    bool parse_bson_internal()
     {
-        std::int32_t documentSize;
-        get_number_little_endian(documentSize);
-
-        if (not JSON_UNLIKELY(sax->start_object(-1)))
-        {
-            return false;
-        }
-
         while (auto entry_type = get())
         {
             switch (entry_type)
@@ -6223,8 +6214,46 @@ class binary_reader
                     parse_bson_internal();
                 }
                 break;
+                case 0x04: // array
+                {
+                    string_t key;
+                    get_bson_cstr(key);
+                    sax->key(key);
+                    parse_bson_array();
+                }
+                break;
             }
         }
+    }
+
+    bool parse_bson_array()
+    {
+        std::int32_t documentSize;
+        get_number_little_endian(documentSize);
+
+        if (not JSON_UNLIKELY(sax->start_array(-1)))
+        {
+            return false;
+        }
+
+        parse_bson_entries();
+
+        const auto result = sax->end_array();
+
+        return result;
+    }
+
+    bool parse_bson_internal()
+    {
+        std::int32_t documentSize;
+        get_number_little_endian(documentSize);
+
+        if (not JSON_UNLIKELY(sax->start_object(-1)))
+        {
+            return false;
+        }
+
+        parse_bson_entries();
 
         const auto result = sax->end_object();
 
@@ -8628,6 +8657,28 @@ class binary_writer
         return /*id*/ 1ul + name.size() + 1ul + embedded_document_size;
     }
 
+    std::size_t write_bson_array(const typename BasicJsonType::string_t& name, const BasicJsonType& j)
+    {
+        oa->write_character(static_cast<CharType>(0x04)); // object
+        oa->write_characters(
+            reinterpret_cast<const CharType*>(name.c_str()),
+            name.size() + 1u);
+
+
+        auto document_size_offset = oa->reserve_characters(4ul);
+        std::int32_t embedded_document_size = 5ul;
+
+        for (const auto& el : *j.m_value.array)
+        {
+            embedded_document_size += write_bson_object_entry("", el);
+        }
+
+        oa->write_character(static_cast<CharType>(0x00));
+        write_number_little_endian_at(document_size_offset, embedded_document_size);
+
+        return /*id*/ 1ul + name.size() + 1ul + embedded_document_size;
+    }
+
     std::size_t write_bson_object_entry(const typename BasicJsonType::string_t& name, const BasicJsonType& j)
     {
         switch (j.type())
@@ -8637,6 +8688,8 @@ class binary_writer
                 break;
             case value_t::object:
                 return write_bson_object_internal(name, j);
+            case value_t::array:
+                return write_bson_array(name, j);
             case value_t::boolean:
                 return write_bson_boolean(name, j);
             case value_t::number_float:

test/src/unit-bson.cpp

@@ -354,7 +354,6 @@ TEST_CASE("BSON")
 
         SECTION("non-empty object with object member")
         {
-            // directly encoding uint64 is not supported in bson (only for timestamp values)
             json j =
             {
                 { "entry", json::object() }
@@ -381,6 +380,34 @@ TEST_CASE("BSON")
             CHECK(json::from_bson(result, true, false) == j);
         }
 
+        SECTION("non-empty object with array member")
+        {
+            json j =
+            {
+                { "entry", json::array() }
+            };
+
+            std::vector<uint8_t> expected =
+            {
+                0x11, 0x00, 0x00, 0x00, // size (little endian)
+                0x04, /// entry: embedded document
+                'e', 'n', 't', 'r', 'y', '\x00',
+
+                0x05, 0x00, 0x00, 0x00, // size (little endian)
+                // no entries
+                0x00, // end marker (embedded document)
+
+                0x00 // end marker
+            };
+
+            const auto result = json::to_bson(j);
+            CHECK(result == expected);
+
+            // roundtrip
+            CHECK(json::from_bson(result) == j);
+            CHECK(json::from_bson(result, true, false) == j);
+        }
+
         SECTION("Some more complex document")
         {
             // directly encoding uint64 is not supported in bson (only for timestamp values)