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jsoncons::cbor::cbor_view

A cbor_view is a non-owning reference to a contiguous sequence of bytes within a packed cbor object. The first byte in the sequence contains the type of the CBOR value.

Header

#include <jsoncons_ext/cbor/cbor.hpp>

class cbor_view
Member type Definition
value_type cbor_view
reference cbor_view&
const_reference const cbor_view&
pointer cbor_view*
const_pointer const cbor_view*
string_type std::string
key_value_type key_value_pair_view<cbor_view>
string_view_type A non-owning view of a string, holds a pointer to character data and length. Supports conversion to and from strings. Will be typedefed to the C++ 17 string view if JSONCONS_HAS_STRING_VIEW is defined in jsoncons_config.hpp, otherwise proxied.
const_object_iterator A const ForwardIterator to const key_value_type
object_iterator Same as const_object_iterator
const_array_iterator A const ForwardIterator to cbor_view
array_iterator Same as const_array_iterator

Constructors

cbor_view(); // (1)

cbor_view(const uint8_t* buffer, size_t buflen); // (2)

cbor_view(const std::vector<uint8_t>& buffer); // (3)

cbor_view(const cbor_view& other); // (4)

(1) Constructs an empty cbor_view with the result that buffer() is nullptr and buflen() is 0.

(2) Constructs a cbor_view on the first buflen bytes of the buffer.

(3) Constructs a cbor_view on buffer.

(4) Constructs a cbor_view on the same content as other.

CBOR buffer view

const uint8_t* buffer() const Returns a pointer to the first byte of the CBOR buffer view.
size_t buflen() const Returns length of CBOR buffer view.

Ranges and Iterators

array_range Returns a "range" that supports a range-based for loop over the elements of a cbor_view array.
obect_range Returns a "range" that supports a range-based for loop over the key-value pairs of a cbor_view object.

Capacity

size_t size() const Returns the length of the array or map if the first byte in the CBOR buffer is a CBOR tag that indicates an array or map, otherwise false.
bool empty() const Returns true if a CBOR string, object or array has no elements, otherwise false

Accessors

is Checks if a CBOR packed value matches a type.
as Attempts to convert a CBOR packed value to a value of a type.
cbor_view operator[](size_t pos) const Returns a view of the CBOR array element at specified index pos.
cbor_view operator[](const string_view_type& key) const Returns a view of the CBOR object member value with key equivalent to key.
cbor_view at(size_t pos) const Returns a view of the CBOR array element at specified index pos.
cbor_view at(const string_view_type& key) const Returns a view of the CBOR object member value with key equivalent to key.

Serialization

dump Serializes json value to a string, stream, or output handler.

Non member functions

std::ostream& operator<< (std::ostream& os, const cbor_view& val)

Inserts CBOR value into stream.

Select values from cbor_view object

A cbor_view satisfies the requirements for jsonpointer::get.

#include <jsoncons/json.hpp>
#include <jsoncons_ext/jsonpointer/jsonpointer.hpp>
#include <jsoncons_ext/cbor/cbor.hpp>

using namespace jsoncons;

int main()
{
    ojson j = ojson::parse(R"(
    {
       "application": "hiking",
       "reputons": [
       {
           "rater": "HikingAsylum.example.com",
           "assertion": "is-good",
           "rated": "sk",
           "rating": 0.90
         }
       ]
    }
    )");

    std::vector<uint8_t> data;
    cbor::encode_cbor(j, data);

    std::error_code ec;
    cbor::cbor_view rated = jsonpointer::get(cbor::cbor_view(data), "/reputons/0/rated", ec);
    cbor::cbor_view rating = jsonpointer::get(cbor::cbor_view(data), "/reputons/0/rating", ec);

    std::cout << rated.as_string() << ", " << rating.as_double() << std::endl;
}

Output:

sk, 0.9

See also