1Type 5 – Maps
2=============================
3
4CBOR maps are the plain old associative maps similar JSON objects or Python dictionaries.
5
6Definite maps have a fixed size which is stored in the header, whereas indefinite maps do not and are terminated by a special "break" byte instead.
7
8Map are explicitly created or decoded as definite or indefinite and will be encoded using the corresponding wire representation, regardless of whether the actual size is known at the time of encoding.
9
10.. note::
11
12  Indefinite maps can be conveniently used with streaming :doc:`decoding <streaming_decoding>` and :doc:`encoding <streaming_encoding>`.
13  Keys and values can simply be output one by one, alternating keys and values.
14
15.. warning:: Any CBOR data item is a legal map key (not just strings).
16
17==================================  =====================================================================================
18Corresponding :type:`cbor_type`     ``CBOR_TYPE_MAP``
19Number of allocations (definite)    Two plus any manipulations with the data
20Number of allocations (indefinite)  Two plus logarithmically many
21                                    reallocations relative to additions
22Storage requirements (definite)     ``sizeof(cbor_pair) * size + sizeof(cbor_item_t)``
23Storage requirements (indefinite)   ``<= sizeof(cbor_item_t) + sizeof(cbor_pair) * size * BUFFER_GROWTH``
24==================================  =====================================================================================
25
26Examples
27~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
28
29::
30
31    0xbf        Start indefinite map (represents {1: 2})
32        0x01        Unsigned integer 1 (key)
33        0x02        Unsigned integer 2 (value)
34        0xff        "Break" control token
35
36::
37
38    0xa0        Map of size 0
39
40Getting metadata
41~~~~~~~~~~~~~~~~~
42.. doxygenfunction:: cbor_map_size
43.. doxygenfunction:: cbor_map_allocated
44.. doxygenfunction:: cbor_map_is_definite
45.. doxygenfunction:: cbor_map_is_indefinite
46
47Reading data
48~~~~~~~~~~~~~
49
50.. doxygenfunction:: cbor_map_handle
51
52Creating new items
53~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
54
55.. doxygenfunction:: cbor_new_definite_map
56.. doxygenfunction:: cbor_new_indefinite_map
57
58
59Modifying items
60~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
61
62.. doxygenfunction:: cbor_map_add
63