A way to store a byte array

[rubend056]

Is there a way to store a byte array of a specific size?

I'm asking because I wanted to implement the ToRecord trait for my own struct Limb:

impl ToRecord for &Limb {
	fn store(&self, buf: &mut std::vec::Vec<u8>) {
		buf.write(&postcard::to_vec::<_, 32>(self).unwrap()).unwrap();
	}
	fn format_char(&self) -> u8 {
		b'L'
	}
	fn size(&self) -> usize {
		32
	}
	fn variable_size(&self) -> bool {
		false
	}
}

but I got a panic on row_format.rs on line 151:
panic!("invalid format character '{}'", a);

There seems to be more to extending the formats stored than just implementing ToRecord/FromRecord. Is there an easier way to do this? Or should I just use 's' with base64 encoding?

[njaard]

Sorry about my delay in responding.

The code in row_format.rs is necessary for receiving information from command-line tools.

Anyway, I've added this feature in the byte-arrays branch

Let me know if that works for you and I will merge it.

[rubend056]

Wow thank you for the work you put into this :)

Since then I've been using 's' with a base64 encoding, it seems you're doing the same but with a different format_char 'B'.

Would your implementation have any performance/size benefits over just using 's' with base64?

[njaard]

I conducted an experiment to see if compressing a base64 string with LZ4 results in the same size as compressing the same data when represented in binary, and it's about 30% more.

So, yes, there's a size benefit of not using base64, and converting to base64 probably has cost as well.