shadow_rs/utility/
stream_len.rsuse std::io::{Seek, SeekFrom};
pub trait StreamLen {
fn stream_len_bp(&mut self) -> std::io::Result<u64>;
}
impl<T> StreamLen for T
where
T: Seek,
{
fn stream_len_bp(&mut self) -> std::io::Result<u64> {
let current = self.stream_position()?;
let end = self.seek(SeekFrom::End(0))?;
if current != end {
self.seek(SeekFrom::Start(current))?;
}
Ok(end)
}
}
#[cfg(test)]
mod tests {
use std::io::Cursor;
use super::*;
#[test]
fn test_stream_len_bp() -> std::io::Result<()> {
let data = [0, 1, 2, 3, 4, 5];
let mut cursor = Cursor::new(&data);
assert_eq!(cursor.stream_len_bp()?, 6);
assert_eq!(cursor.position(), 0);
cursor.seek(SeekFrom::Start(2))?;
assert_eq!(cursor.stream_len_bp()?, 6);
assert_eq!(cursor.position(), 2);
cursor.seek(SeekFrom::End(0))?;
assert_eq!(cursor.stream_len_bp()?, 6);
assert_eq!(cursor.position(), 6);
Ok(())
}
}