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tlv_decoder

TLV stands for "Type-Length-Value," a data structure used to encapsulate multiple pieces of information into a single byte sequence.

Features

  • Encode a list of TLV entries into bytes.
  • Decode bytes into a list of TLV entries.
  • BER/DER length fields, both short and long form:
    • 0x00–0x7F for lengths 0–127.
    • 0x81 LL for lengths 128–255.
    • 0x82 LL LL for lengths 256–65535.
    • 0x83/0x84 … for larger lengths.
  • Input validation with clear FormatException messages for truncated or unsupported input.

Getting started

dependencies:
  tlv_decoder: ^0.0.5

Usage

import 'dart:typed_data';

import 'package:tlv_decoder/tlv_decoder.dart';

void main() {
  // Decoding
  final data = Uint8List.fromList(
    [0x01, 0x03, 0x41, 0x42, 0x43, 0x02, 0x02, 0x44, 0x45],
  );
  final List<TLV> tlvList = TlvUtils.decode(data);

  // Encoding
  final encoded = TlvUtils.encode([
    TLV(type: 1, length: 3, value: Uint8List.fromList([0x41, 0x42, 0x43])),
    TLV(type: 2, length: 2, value: Uint8List.fromList([0x44, 0x45])),
  ]);
}

TLV.length is informational; TlvUtils.encode always derives the length field from the value bytes.

Features and bugs

Please file feature requests and bugs at the issue tracker.

License

Project under MIT license.

Libraries

tlv_decoder