What integer size is used for length delimiter?

[matthewmturner]

When using encode_length_delimited or decode_length_delimited what integer size is used to represent the length? I have mutiple protocol buf messages in a file and i want to iterate through and read them but i think i need to allocate a buffer of the right size in order to do this - which would require knowing the size of the length delimiter.

Unless i'm doing something wrong?

Thanks!

[fd]

As per the documentation you should expect a length delimiter to be between 1 and 10 bytes. It is encoded as a variable length uint64. The easiest way to read a length delimited stream is to uses a buffered stream and and peek the first 10 bytes from the stream to decode the length. then use prost::length_delimiter_len to know the number of bytes to skip.

[matthewmturner]

@fd thank you for the response! im not sure how i missed that going through the documents. do you have any recommendations for working with variable length integers in rust?

appreciate the help!

[mumbleskates]

turns out you can also just pass &mut impl Buf anyway, instead of by-value, because there's a blanket implementation for that in the Bytes crate. so the by-val signature makes mutating the original buf optional, rather than mandatory.