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92 lines
3.0 KiB
Markdown
92 lines
3.0 KiB
Markdown
# nlohmann::basic_json::to_bon8
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```
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// (1)
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static std::vector<std::uint8_t> to_bon8(const basic_json& j);
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// (2)
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static void to_bon8(const basic_json& j, detail::output_adapter<std::uint8_t> o);
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static void to_bon8(const basic_json& j, detail::output_adapter<char> o);
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```
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Serializes a given JSON value `j` to a byte vector using the BON8 (Binary Object Notation 8) serialization format. BON8 is a compact binary serialization format that stores strings as UTF-8 without a length prefix.
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1. Returns a byte vector containing the BON8 serialization.
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1. Writes the BON8 serialization to an output adapter.
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The exact mapping and its limitations are described on a [dedicated page](https://json.nlohmann.me/features/binary_formats/bon8/index.md).
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## Parameters
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`j` (in) : JSON value to serialize
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`o` (in) : output adapter to write serialization to
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## Return value
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1. BON8 serialization as a byte vector
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1. (none)
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## Exception safety
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Strong guarantee: if an exception is thrown, there are no changes in the JSON value `j`, which is never modified. With (2), the bytes written before the exception remain in the output adapter.
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## Exceptions
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- Throws [out_of_range.407](https://json.nlohmann.me/home/exceptions/#jsonexceptionout_of_range407) if `j` contains an unsigned integer above 9223372036854775807, which BON8 cannot represent
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- Throws [type_error.316](https://json.nlohmann.me/home/exceptions/#jsonexceptiontype_error316) if `j` contains a string that is not valid UTF-8
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## Complexity
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Linear in the size of the JSON value `j`.
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## Examples
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Example
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The example shows the serialization of a JSON value to a byte vector in BON8 format.
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```
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#include <iostream>
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#include <iomanip>
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#include <nlohmann/json.hpp>
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using json = nlohmann::json;
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using namespace nlohmann::literals;
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int main()
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{
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// create a JSON value
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json j = R"({"compact": true, "format": "BON8", "schema": 0})"_json;
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// serialize it to BON8
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std::vector<std::uint8_t> v = json::to_bon8(j);
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// print the vector content
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for (auto& byte : v)
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{
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std::cout << "0x" << std::hex << std::setw(2) << std::setfill('0') << (int)byte << " ";
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}
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std::cout << std::endl;
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}
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```
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Output:
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```
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0x89 0x63 0x6f 0x6d 0x70 0x61 0x63 0x74 0xf9 0x66 0x6f 0x72 0x6d 0x61 0x74 0xff 0x42 0x4f 0x4e 0x38 0xff 0x73 0x63 0x68 0x65 0x6d 0x61 0x90
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```
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## See also
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- [from_bon8](https://json.nlohmann.me/api/basic_json/from_bon8/index.md) create a JSON value from an input in BON8 format
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- [to_cbor](https://json.nlohmann.me/api/basic_json/to_cbor/index.md) create a CBOR serialization of a JSON value
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- [to_msgpack](https://json.nlohmann.me/api/basic_json/to_msgpack/index.md) create a MessagePack serialization of a JSON value
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- [to_bson](https://json.nlohmann.me/api/basic_json/to_bson/index.md) create a BSON serialization of a JSON value
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- [to_ubjson](https://json.nlohmann.me/api/basic_json/to_ubjson/index.md) create a UBJSON serialization of a JSON value
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- [to_bjdata](https://json.nlohmann.me/api/basic_json/to_bjdata/index.md) create a BJData serialization of a JSON value
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## Version history
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- Added in version 3.13.0.
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