Crate nanondef 

nanondef

nanondef is a compact, no_std-friendly NFC Forum NDEF encoding and decoding library, designed for embedded systems, WASM runtimes, and efficient tag-parsing pipelines.

The crate provides:

• Fully-typed decoding of NDEF Messages, Records, and Payloads
• Zero-copy parsing via lifetimes (&[u8])
• Pluggable DecodePayload trait for supporting custom payload types
• Compact encoding via the Encode trait (with heapless::Vec support)
• Strongly typed NFC Capability Container (CC) components:
  • [CapabilityContainer]
  • [Version] (nibble-packed major/minor)
  • [Features] (bitflag wrapper)
• Optional serde support for serialization
• Optional wasm_bindgen bindings
• Works in no_std, alloc, or full std environments

The library aims to be:

• Correct – adheres to NFC Forum Type 2 / NDEF encoding rules
• Minimal – no dependencies by default (only heapless optionally)
• Zero-copy – payload fields borrow directly from the input buffer
• Flexible – users can define custom payload decoders

Getting Started

Decode a full NDEF message from a byte slice

use nanondef::message::{
    record::{payload::UriPayload, Record, Tnf},
    DecodeMessage, HeaplessMessage, MessageRecords,
};

// A single-record NDEF message containing a URI payload
let bytes: &[u8] = &[
    0b1101_0001, // MB | ME | SR | TNF=WellKnown
    0x01,        // Type length = 1 ("U")
    0x0B,        // Payload length
    b'U',        // Type field
    0x03,        // Prefix code: "http://"
    b'g',
    b'i',
    b't',
    b'h',
    b'u',
    b'b',
    b'.',
    b'c',
    b'o',
    b'm',
];

// Decode the message
let msg = HeaplessMessage::<1>::decode_message(bytes).expect("should decode message");

// Extract the payload as a typed URI payload
let records = msg.records().expect("should provide records");
let Record::Uri(uri) = &records[0] else { panic!("should be a URI record") };

assert_eq!(uri.header.tnf, Tnf::WellKnown);
assert_eq!(uri.payload.prefix, "http://");
assert_eq!(uri.payload.uri, "github.com");

Re-exports

pub use error::Error;

Modules

error

Error types and error-construction helpers for NDEF encoding and decoding.

ffi

tag

Structs

Range

A half-open range of usize values represented as (start, end).

Vecstd or alloc

A contiguous growable array type, written as Vec<T>, short for ‘vector’.

Traits

AsBytes

Encode

A trait for producing an encoded byte representation of a value.

Type Aliases

Consumed

A value paired with the number of bytes consumed while decoding it.

ConsumedResult

A result that returns a parsed value together with the number of bytes consumed while parsing it.

CrateConsumed

Convenience alias for the crate’s standard Result type returning a parsed value together with the number of bytes consumed.

OffsetResult

A result that returns only the number of bytes consumed.

Result