Crate minicbor

A small CBOR codec suitable for no_std environments.

The crate is organised around the following entities:

• Encoder and Decoder for type-directed encoding and decoding of values.

• Encode and Decode traits which can be implemented for any type that should be encoded to or decoded from CBOR. They are similar to serde’s Serialize and Deserialize traits but do not abstract over the encoder/decoder.

Encoding and decoding proceeds in a type-directed way, i.e. by calling methods for expected data item types, e.g. Decoder::u32 or Encoder::str. In addition there is support for data type inspection. The Decoder can be queried for the current data type which returns a data::Type that can represent every possible CBOR type and decoding can thus proceed based on this information. It is also possible to just tokenize the input bytes using a Tokenizer, i.e. an Iterator over CBOR Tokens.

Optionally, Encode and Decode can be derived for structs and enums using the respective derive macros (requires feature "derive"). See minicbor_derive for details.

For I/O support see minicbor-io.

Example: generic encoding and decoding

use minicbor::{Encode, Decode};

let input = ["hello", "world"];
let mut buffer = [0u8; 128];

minicbor::encode(&input, buffer.as_mut())?;
let output: [&str; 2] = minicbor::decode(buffer.as_ref())?;
assert_eq!(input, output);

Example: ad-hoc encoding

use minicbor::Encoder;

let mut buffer = [0u8; 128];
let mut encoder = Encoder::new(&mut buffer[..]);

encoder.begin_map()? // using an indefinite map here
    .str("hello")?.str("world")?
    .str("submap")?.map(2)?
        .u8(1)?.bool(true)?
        .u8(2)?.bool(false)?
    .u16(34234)?.array(3)?.u8(1)?.u8(2)?.u8(3)?
    .bool(true)?.null()?
.end()?;

Example: ad-hoc decoding

use minicbor::Decoder;
use minicbor::data::Tag;

let input = [
    0xc0, 0x74, 0x32, 0x30, 0x31, 0x33, 0x2d, 0x30,
    0x33, 0x2d, 0x32, 0x31, 0x54, 0x32, 0x30, 0x3a,
    0x30, 0x34, 0x3a, 0x30, 0x30, 0x5a
];

let mut decoder = Decoder::new(&input);
assert_eq!(Tag::DateTime, decoder.tag()?);
assert_eq!("2013-03-21T20:04:00Z", decoder.str()?);

Example: tokenization

use minicbor::display;
use minicbor::decode::{Token, Tokenizer};

let input  = [0x83, 0x01, 0x9f, 0x02, 0x03, 0xff, 0x82, 0x04, 0x05];

assert_eq!("[1, [_ 2, 3], [4, 5]]", format!("{}", display(&input)));

let tokens = Tokenizer::new(&input).collect::<Result<Vec<Token>, _>>()?;

assert_eq! { &tokens[..],
    &[Token::Array(3),
      Token::U8(1),
      Token::BeginArray,
      Token::U8(2),
      Token::U8(3),
      Token::Break,
      Token::Array(2),
      Token::U8(4),
      Token::U8(5)]
};

Re-exports

pub use decode::Decode;

pub use encode::Encode;

Modules

bytes	Newtypes for &[u8] and Vec<u8>.
data	Information about CBOR data types and tags.
decode	Traits and types for decoding CBOR.
encode	Traits and types for encoding CBOR.

Structs

Decoder	A non-allocating CBOR decoder.
Encoder	A non-allocating CBOR encoder writing encoded bytes to the given Write sink.

Functions

decode	Decode a type implementing Decode from the given byte slice.
display	Display the given CBOR bytes in diagnostic notation.
encode	Encode a type implementing Encode to the given encode::Write impl.
to_vec	Encode a type implementing Encode and return the encoded byte vector.

Derive Macros

Decode	Derive the minicbor::Decode trait for a struct or enum.
Encode	Derive the minicbor::Encode trait for a struct or enum.