embedded-exfat

An exFAT Library in rust mainly focusing on no_std embedded system with async support

alloc is mandatory for this crate, although memory allocation is minimized, 256B for upcase table and 12B plus name size for each file or directory, and 12B for root directory.

For async scenario, enable tokio feature if std library available otherwide enable async feature

For no_std scenario, be aware that thread safety is provided by spin crate, which potenitally leads to dead lock.

Using this crate

use std::io::Write;
use exfat::error::Error;
use exfat::io::std::FileIO;
use exfat::ExFAT;
use exfat::FileOrDirectory;

let io = FileIO::open(device).map_err(|e| Error::IO(e)).unwrap();
let mut exfat = ExFAT::new(io).unwrap();
exfat.validate_checksum().unwrap();
let mut root = exfat.root_directory().unwrap();
root.validate_upcase_table_checksum().unwrap();
let mut file = match root.open().unwrap().open("test.txt").unwrap() {
    FileOrDirectory::File(f) => f,
    FileOrDirectory::Directory(_) => panic!("Not a file"),
};
let mut stdout = std::io::stdout();
let mut buf = [0u8; 512];
loop {
    let size = file.read(&mut buf).unwrap();
    stdout.write_all(&buf[..size]).unwrap();
    if size < buf.len() {
        break;
    }
}

Features

• async

  Enable async support

• tokio

  Enable async support with tokio

• smol

  Enable async support with smol

• std (enable by default)

  Use std library

• extern-datetime-now

  Link an external exfat_datetime_now function to get current datetime, If not enabled, a default datetime will be used.

• logging

  Enable logging, otherwise disabled at compile time

• max-filename-size-30

  Limit filename size to 30 bytes to reduce stack cost, any file or directory name longer than this size will be ignored, creating file with name size exceeds will return error.