2021-32-bit-holiday-jam/src/file.rs

use std::convert::TryInto;
use std::fs::File;
use std::io::Read;
use std::path::Path;

#[derive (Debug)]
pub enum LoadFileErr {
	FileTooBig,
	Io (std::io::Error),
}

impl From <std::io::Error> for LoadFileErr {
	fn from (e: std::io::Error) -> Self {
		Self::Io (e)
	}
}

pub fn load_small_file <P> (name: P, max_size: u64)
-> Result <Vec <u8>, LoadFileErr>
where P: AsRef <Path> 
{
	let mut f = File::open (name)?;
	let len = f.metadata ()?.len ();
	
	if len > max_size {
		return Err (LoadFileErr::FileTooBig);
	}
	
	let mut data = vec! [0u8; len.try_into ().unwrap ()];
	
	f.read_exact (&mut data [..])?;
	
	Ok (data)
}