json/docs/mkdocs/docs/api/basic_json/to_bjdata.md

nlohmann::basic_json::to_bjdata

// (1)
static std::vector<std::uint8_t> to_bjdata(const basic_json& j,
                                           const bool use_size = false,
                                           const bool use_type = false,
                                           const bjdata_version_t version = bjdata_version_t::draft2);

// (2)
static void to_bjdata(const basic_json& j, detail::output_adapter<std::uint8_t> o,
                      const bool use_size = false, const bool use_type = false,
                      const bjdata_version_t version = bjdata_version_t::draft2);
static void to_bjdata(const basic_json& j, detail::output_adapter<char> o,
                      const bool use_size = false, const bool use_type = false,
                      const bjdata_version_t version = bjdata_version_t::draft2);

Serializes a given JSON value j to a byte vector using the BJData (Binary JData) serialization format. BJData aims to be more compact than JSON itself, yet more efficient to parse.

1. Returns a byte vector containing the BJData serialization.
2. Writes the BJData serialization to an output adapter.

The exact mapping and its limitations is described on a dedicated page.

Parameters

j (in)

JSON value to serialize

o (in)

output adapter to write serialization to

use_size (in)

whether to add size annotations to container types; optional, #!cpp false by default.

use_type (in)

whether to add type annotations to container types (must be combined with #!cpp use_size = true); optional, #!cpp false by default.

version (in)

which version of BJData to use (see note on "Binary values" on BJData); optional, #!cpp bjdata_version_t::draft2 by default.

Return value

1. BJData serialization as byte vector
2. (none)

Exception safety

Strong guarantee: if an exception is thrown, there are no changes in the JSON value.

Complexity

Linear in the size of the JSON value j.

Examples

??? example

The example shows the serialization of a JSON value to a byte vector in BJData format.
 
```cpp
--8<-- "examples/to_bjdata.cpp"
```

Output:

```json
--8<-- "examples/to_bjdata.output"
```

Version history

• Added in version 3.11.0.
• BJData version parameter (for draft3 binary encoding) added in version 3.12.0.