Crate written_size

This crate provides a way to calculate how much data is being written into std::io::Write. This is mostly useful if you want to know how much space is necessary to serialize something without actually allocating that space or writing data anywhere.

Example usage:

use std::io::Write;
use written_size::WrittenSize;

let mut ws = WrittenSize::new();
ws.write(&[1, 2, 3]).unwrap();
ws.write(&[1, 2, 3]).unwrap();

assert!(ws.size() == 6);

If you want to write data to some other Write instance and at the same time calculating number of bytes written you can use this crate together with the broadcast crate.

If you want to calculate number of bytes read from some Read instance you can use this crate together with the tee crate.

Structs

WrittenSize

Simple wrapper around u64 which implements std::io::Write. It calculates how much data was written discarding the data itself.