allocator_type array array_t at at at at at at back back basic_json basic_json basic_json basic_json basic_json basic_json basic_json basic_json begin begin boolean_t cbegin cend clear const_iterator const_pointer const_reference const_reverse_iterator count crbegin crend detail::external_constructor diff difference_type dump emplace emplace_back empty end end erase erase erase erase exception find find flatten from_cbor from_msgpack front front get get get get get get_allocator get_ptr get_ptr get_ref get_ref insert insert insert insert insert insert invalid_iterator is_array is_boolean is_discarded is_null is_number is_number_float is_number_integer is_number_unsigned is_object is_primitive is_string is_structured iterator iterator_wrapper iterator_wrapper json_serializer max_size meta number_float_t number_integer_t number_unsigned_t object object_t operator value_t operator ValueType operator!= operator!= operator!= operator+= operator+= operator+= operator+= operator< operator< operator< operator<< operator<< operator<= operator<= operator<= operator= operator== operator== operator== operator> operator> operator> operator>= operator>= operator>= operator>> operator>> operator[] operator[] operator[] operator[] operator[] operator[] operator[] operator[] operator[] operator[] other_error out_of_range parse parse parse parse parse parse parse_error parse_event_t parser_callback_t patch pointer push_back push_back push_back push_back rbegin rbegin reference rend rend reverse_iterator size size_type string_t swap swap swap swap to_cbor to_msgpack type type_error type_name unflatten value value value value value_t value_type ~basic_json

to_cbor() 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> static std::vector<uint8_t> nlohmann::basic_json::to_cbor ( const basic_json &  j ) inlinestatic Serializes a given JSON value j to a byte vector using the CBOR (Concise Binary Object Representation) serialization format. CBOR 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 CBOR types according to the CBOR specification (RFC 7049): JSON value type value/range CBOR type first byte null null Null 0xf6 boolean true True 0xf5 boolean false False 0xf4 number_integer -9223372036854775808..-2147483649 Negative integer (8 bytes follow) 0x3b number_integer -2147483648..-32769 Negative integer (4 bytes follow) 0x3a number_integer -32768..-129 Negative integer (2 bytes follow) 0x39 number_integer -128..-25 Negative integer (1 byte follow) 0x38 number_integer -24..-1 Negative integer 0x20..0x37 number_integer 0..23 Integer 0x00..0x17 number_integer 24..255 Unsigned integer (1 byte follow) 0x18 number_integer 256..65535 Unsigned integer (2 bytes follow) 0x19 number_integer 65536..4294967295 Unsigned integer (4 bytes follow) 0x1a number_integer 4294967296..18446744073709551615 Unsigned integer (8 bytes follow) 0x1b number_unsigned 0..23 Integer 0x00..0x17 number_unsigned 24..255 Unsigned integer (1 byte follow) 0x18 number_unsigned 256..65535 Unsigned integer (2 bytes follow) 0x19 number_unsigned 65536..4294967295 Unsigned integer (4 bytes follow) 0x1a number_unsigned 4294967296..18446744073709551615 Unsigned integer (8 bytes follow) 0x1b number_float any value Double-Precision Float 0xfb string length: 0..23 UTF-8 string 0x60..0x77 string length: 23..255 UTF-8 string (1 byte follow) 0x78 string length: 256..65535 UTF-8 string (2 bytes follow) 0x79 string length: 65536..4294967295 UTF-8 string (4 bytes follow) 0x7a string length: 4294967296..18446744073709551615 UTF-8 string (8 bytes follow) 0x7b array size: 0..23 array 0x80..0x97 array size: 23..255 array (1 byte follow) 0x98 array size: 256..65535 array (2 bytes follow) 0x99 array size: 65536..4294967295 array (4 bytes follow) 0x9a array size: 4294967296..18446744073709551615 array (8 bytes follow) 0x9b object size: 0..23 map 0xa0..0xb7 object size: 23..255 map (1 byte follow) 0xb8 object size: 256..65535 map (2 bytes follow) 0xb9 object size: 65536..4294967295 map (4 bytes follow) 0xba object size: 4294967296..18446744073709551615 map (8 bytes follow) 0xbb Note The mapping is complete in the sense that any JSON value type can be converted to a CBOR value. The following CBOR types are not used in the conversion: byte strings (0x40..0x5f) UTF-8 strings terminated by "break" (0x7f) arrays terminated by "break" (0x9f) maps terminated by "break" (0xbf) date/time (0xc0..0xc1) bignum (0xc2..0xc3) decimal fraction (0xc4) bigfloat (0xc5) tagged items (0xc6..0xd4, 0xd8..0xdb) expected conversions (0xd5..0xd7) simple values (0xe0..0xf3, 0xf8) undefined (0xf7) half and single-precision floats (0xf9-0xfa) break (0xff) Parameters [in] j JSON value to serialize Returns MessagePack serialization as byte vector Complexity Linear in the size of the JSON value j. Example The example shows the serialization of a JSON value to a byte vector in CBOR format. #include "json.hpp" #include <iomanip> // for std::setw using json = nlohmann::json; int main() { // create a JSON value json j = R"({"compact": true, "schema": 0})"_json; // serialize it to CBOR std::vector<uint8_t> v = json::to_cbor(j); // print the vector content for (auto& byte : v) { std::cout << "0x" << std::hex << std::setw(2) << std::setfill('0') << (int)byte << " "; } std::cout << std::endl; } Output (play with this example online): 0xa2 0x67 0x63 0x6f 0x6d 0x70 0x61 0x63 0x74 0xf5 0x66 0x73 0x63 0x68 0x65 0x6d 0x61 0x00 The example code above can be translated with g++ -std=c++11 -Isrc doc/examples/to_cbor.cpp -o to_cbor See also http://cbor.io from_cbor(const std::vector<uint8_t>&, const size_t) for the analogous deserialization to_msgpack(const basic_json& for the related MessagePack format Since version 2.0.9 Definition at line 9267 of file json.hpp.