CODEWITHSUNDEEP
flutterdart
ch271828n
ch271828n

Reputation: 17587

Most brief way to encode binary blob in Dart code?

I need to encode some binary blob (say, 100KB) in Dart code. Do not want to put it in a separate file, but hope can put it in .dart code (because, for example, I want the excellent flutter hot restart instead of rebuilding the Flutter app again and again if the file chages).

What is the most brief way to do so?

For example I can come up with final bytes = [100, 70, 220, 132, ...]; but it will make the .dart file huge.

I can also do final data = 'aGVsbG8...' and use it by base64.decode(data), but it takes up 33% extra space in generated binary.

Upvotes: 0

Views: 457

Answers (2)

relent95
relent95

Reputation: 4731

I recently confronted this problem and found a solution better than the base64 encoding. You can utilize unicode characters from '\x00' to 'xff' like the following example.

import 'dart:typed_data';

void main() {
  final bytes = Uint8List.fromList("\x01\x02\xfe\xff".codeUnits);
  for (var b in bytes) {
    print(b);
  }
}

This produces an efficient executable with 4 bytes "\x01\x02\xfe\xff" data, at least in my Linux Box.

Upvotes: 0

Ben Konyi
Ben Konyi

Reputation: 3219

Unfortunately those are your options as there's no way to export binary data from a file (i.e., like directly generating a .o file that exports a symbol in C/C++) without using either a Dart list or some other form of encoding.

However, if you're dealing with fixed binary data representations, I'd highly recommend looking at types provided in dart:typed_data to ensure you're storing this data in memory efficiently (e.g., using UInt8List vs List<int> will use 8-bits per element instead of the 64-bits that can be represented by int).

Upvotes: 0

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