to_msgpack() [1/3]

template<template< typename U, typename V, typename... Args > class ObjectType = std::map, template< typename U, typename... Args > class ArrayType = std::vector, class StringType = std::string, class BooleanType = bool, class NumberIntegerType = std::int64_t, class NumberUnsignedType = std::uint64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator, template< typename T, typename SFINAE=void > class JSONSerializer = adl_serializer, class BinaryType = std::vector<std::uint8_t>>

static std::vector< std::uint8_t > nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType >::to_msgpack ( const basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType > &  j )

inlinestatic

create a MessagePack serialization of a given JSON value

Serializes a given JSON value j to a byte vector using the MessagePack serialization format. MessagePack is a binary serialization format which aims to be more compact than JSON itself, yet more efficient to parse.

The library uses the following mapping from JSON values types to MessagePack types according to the MessagePack specification:

JSON value type	value/range	MessagePack type	first byte
null	null	nil	0xC0
boolean	true	true	0xC3
boolean	false	false	0xC2
number_integer	-9223372036854775808..-2147483649	int64	0xD3
number_integer	-2147483648..-32769	int32	0xD2
number_integer	-32768..-129	int16	0xD1
number_integer	-128..-33	int8	0xD0
number_integer	-32..-1	negative fixint	0xE0..0xFF
number_integer	0..127	positive fixint	0x00..0x7F
number_integer	128..255	uint 8	0xCC
number_integer	256..65535	uint 16	0xCD
number_integer	65536..4294967295	uint 32	0xCE
number_integer	4294967296..18446744073709551615	uint 64	0xCF
number_unsigned	0..127	positive fixint	0x00..0x7F
number_unsigned	128..255	uint 8	0xCC
number_unsigned	256..65535	uint 16	0xCD
number_unsigned	65536..4294967295	uint 32	0xCE
number_unsigned	4294967296..18446744073709551615	uint 64	0xCF
number_float	any value representable by a float	float 32	0xCA
number_float	any value NOT representable by a float	float 64	0xCB
string	length: 0..31	fixstr	0xA0..0xBF
string	length: 32..255	str 8	0xD9
string	length: 256..65535	str 16	0xDA
string	length: 65536..4294967295	str 32	0xDB
array	size: 0..15	fixarray	0x90..0x9F
array	size: 16..65535	array 16	0xDC
array	size: 65536..4294967295	array 32	0xDD
object	size: 0..15	fix map	0x80..0x8F
object	size: 16..65535	map 16	0xDE
object	size: 65536..4294967295	map 32	0xDF
binary	size: 0..255	bin 8	0xC4
binary	size: 256..65535	bin 16	0xC5
binary	size: 65536..4294967295	bin 32	0xC6

Note

The mapping is complete in the sense that any JSON value type can be converted to a MessagePack value.

The following values can not be converted to a MessagePack value:

• strings with more than 4294967295 bytes
• byte strings with more than 4294967295 bytes
• arrays with more than 4294967295 elements
• objects with more than 4294967295 elements

Any MessagePack output created to_msgpack can be successfully parsed by from_msgpack.

If NaN or Infinity are stored inside a JSON number, they are serialized properly. This behavior differs from the dump() function which serializes NaN or Infinity to null.

Parameters

[in]

j

JSON value to serialize

Returns

MessagePack serialization as byte vector

@complexity Linear in the size of the JSON value j.

@liveexample{The example shows the serialization of a JSON value to a byte vector in MessagePack format.,to_msgpack}

See also

http://msgpack.org

see from_msgpack for the analogous deserialization

see to_cbor(const basic_json& for the related CBOR format

see to_ubjson(const basic_json&, const bool, const bool) for the related UBJSON format

Since

version 2.0.9

Definition at line 25136 of file json.hpp.

    {
        std::vector<std::uint8_t> result;
        to_msgpack(j, result);
        return result;
    }