#include <jsoncons_ext/cbor/cbor.hpp>
template <typename T,typename ByteContainer>
void encode_cbor(const T& jval, ByteContainer& cont,
const cbor_decode_options& options = cbor_decode_options()); (1)
template <typename T>
void encode_cbor(const T& val, std::ostream& os,
const cbor_encode_options& options = cbor_encode_options()); (2)
template <typename T,typename ByteContainer>
void encode_cbor(const allocator_set<Allocator,TempAllocator>& alloc_set,
const T& jval, ByteContainer& cont,
const cbor_decode_options& options = cbor_decode_options()); (3) (since 0.171.0)
template <typename T>
void encode_cbor(const allocator_set<Allocator,TempAllocator>& alloc_set,
const T& val, std::ostream& os,
const cbor_encode_options& options = cbor_encode_options()); (4) (since 0.171.0)Encodes a C++ data structure to the Concise Binary Object Representation data format.
(1) Writes a value of type T into a byte container in the CBOR data format, using the specified (or defaulted) options.
Type 'T' must be an instantiation of basic_json
or support json_type_traits.
Type ByteContainer must be back insertable and have member type value_type with size exactly 8 bits (since 0.152.0.)
Any of the values types int8_t, uint8_t, char, unsigned char and std::byte (since C++17) are allowed.
(2) Writes a value of type T into a binary stream in the CBOR data format, using the specified (or defaulted) options. Type 'T' must be an instantiation of basic_json or support json_type_traits.
Functions (3)-(4) are identical to (1)-(2) except an allocator_set is passed as an additional argument.
#include <jsoncons/json.hpp>
#include <jsoncons_ext/cbor/cbor.hpp>
using namespace jsoncons;
int main()
{
ojson j1;
j1["zero"] = 0;
j1["one"] = 1;
j1["two"] = 2;
j1["null"] = null_type();
j1["true"] = true;
j1["false"] = false;
j1["max int64_t"] = (std::numeric_limits<int64_t>::max)();
j1["max uint64_t"] = (std::numeric_limits<uint64_t>::max)();
j1["min int64_t"] = (std::numeric_limits<int64_t>::lowest)();
j1["max int32_t"] = (std::numeric_limits<int32_t>::max)();
j1["max uint32_t"] = (std::numeric_limits<uint32_t>::max)();
j1["min int32_t"] = (std::numeric_limits<int32_t>::lowest)();
j1["max int16_t"] = (std::numeric_limits<int16_t>::max)();
j1["max uint16_t"] = (std::numeric_limits<uint16_t>::max)();
j1["min int16_t"] = (std::numeric_limits<int16_t>::lowest)();
j1["max int8_t"] = (std::numeric_limits<int8_t>::max)();
j1["max uint8_t"] = (std::numeric_limits<uint8_t>::max)();
j1["min int8_t"] = (std::numeric_limits<int8_t>::lowest)();
j1["max double"] = (std::numeric_limits<double>::max)();
j1["min double"] = (std::numeric_limits<double>::lowest)();
j1["max float"] = (std::numeric_limits<float>::max)();
j1["zero float"] = 0.0;
j1["min float"] = (std::numeric_limits<float>::lowest)();
j1["Key too long for small string optimization"] = "String too long for small string optimization";
std::vector<uint8_t> cont;
cbor::encode_cbor(j1, cont);
ojson j2 = cbor::decode_cbor<ojson>(cont);
std::cout << pretty_print(j2) << std::endl;
}Output:
{
"zero": 0,
"one": 1,
"two": 2,
"null": null,
"true": true,
"false": false,
"max int64_t": 9223372036854775807,
"max uint64_t": 18446744073709551615,
"min int64_t": -9223372036854775808,
"max int32_t": 2147483647,
"max uint32_t": 4294967295,
"min int32_t": -2147483648,
"max int16_t": 32767,
"max uint16_t": 65535,
"min int16_t": -32768,
"max int8_t": 127,
"max uint8_t": 255,
"min int8_t": -128,
"max double": 1.79769313486232e+308,
"min double": -1.79769313486232e+308,
"max float": 3.40282346638529e+038,
"zero float": 0.0,
"min float": -3.40282346638529e+038,
"Key too long for small string optimization": "String too long for small string optimization"
}#include <jsoncons/json.hpp>
#include <jsoncons_ext/cbor/cbor.hpp>
using namespace jsoncons;
int main()
{
// construct byte string value
std::vector<uint8_t> cont = {'H','e','l','l','o'};
json j(byte_string_arg, cont);
std::vector<uint8_t> buf;
cbor::encode_cbor(j, buf);
std::cout << "(1) " << byte_string_view(buf) << "\n\n";
json j2 = cbor::decode_cbor<json>(buf);
std::cout << "(2) " << j2 << std::endl;
}Output:
(1) 45,48,65,6c,6c,6f
(2) "SGVsbG8"
#include <jsoncons/json.hpp>
#include <jsoncons_ext/cbor/cbor.hpp>
using namespace jsoncons;
int main()
{
// construct byte string value
std::vector<uint8_t> cont = {'H','e','l','l','o'};
json j1(byte_string_arg, cont, semantic_tag::base64);
std::vector<uint8_t> buf;
cbor::encode_cbor(j1, buf);
std::cout << "(1) " << byte_string_view(buf) << "\n\n";
json j2 = cbor::decode_cbor<json>(buf);
std::cout << "(2) " << j2 << std::endl;
}Output:
(1) d6,45,48,65,6c,6c,6f
(2) "SGVsbG8="
Encode packed strings stringref-namespace, stringref
This example taken from CBOR stringref extension shows how to encode a data structure that contains many repeated strings more efficiently.
#include <iomanip>
#include <cassert>
#include <jsoncons/json.hpp>
#include <jsoncons_ext/cbor/cbor.hpp>
using namespace jsoncons;
int main()
{
ojson j = ojson::parse(R"(
[
{
"name" : "Cocktail",
"count" : 417,
"rank" : 4
},
{
"rank" : 4,
"count" : 312,
"name" : "Bath"
},
{
"count" : 691,
"name" : "Food",
"rank" : 4
}
]
)");
auto options = cbor::cbor_encode_options{}
.pack_strings(true);
std::vector<uint8_t> buf;
cbor::encode_cbor(j, buf, options);
std::cout << byte_string_view(buf) << "\n\n";
/*
d90100 -- tag (256)
83 -- array(3)
a3 -- map(3)
64 -- text string (4)
6e616d65 -- "name"
68 -- text string (8)
436f636b7461696c -- "Cocktail"
65 -- text string (5)
636f756e74 -- "count"
1901a1 -- unsigned(417)
64 -- text string (4)
72616e6b -- "rank"
04 -- unsigned(4)
a3 -- map(3)
d819 -- tag(25)
03 -- unsigned(3)
04 -- unsigned(4)
d819 -- tag(25)
02 -- unsigned(2)
190138 -- unsigned(312)
d819 -- tag(25)
00 -- unsigned(0)
64 -- text string(4)
42617468 -- "Bath"
a3 -- map(3)
d819 -- tag(25)
02 -- unsigned(2)
1902b3 -- unsigned(691)
d819 -- tag(25)
00 -- unsigned(0)
64 - text string(4)
466f6f64 -- "Food"
d819 -- tag(25)
03 -- unsigned(3)
04 -- unsigned(4)
*/
ojson j2 = cbor::decode_cbor<ojson>(buf);
assert(j2 == j);
}Output:
d9,01,00,83,a3,64,6e,61,6d,65,68,43,6f,63,6b,74,61,69,6c,65,63,6f,75,6e,74,19,01,a1,64,72,61,6e,6b,04,a3,d8,19,03,04,d8,19,02,19,01,38,d8,19,00,64,42,61,74,68,a3,d8,19,02,19,02,b3,d8,19,00,64,46,6f,6f,64,d8,19,03,04
decode_cbor decodes a Concise Binary Object Representation data format to a json value.