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use std::path::PathBuf;
use std::io::Read;
use std::fs::File;
use std::time::{Instant, Duration};
pub struct ReaderWithSize<R: Read> {
inner: R,
total_size: usize,
total_read: usize,
read_start_time: Option<Instant>,
}
impl<R: Read> ReaderWithSize<R> {
pub fn new(total_size: usize, inner: R) -> Self {
ReaderWithSize{ total_size, total_read: 0, inner, read_start_time: None }
}
pub fn total_read(&self) -> usize {
self.total_read
}
pub fn assummed_total_size(&self) -> usize {
self.total_size
}
pub fn fraction(&self) -> f64 {
(self.total_read as f64)/(self.total_size as f64)
}
pub fn into_inner(self) -> R {
self.inner
}
pub fn inner(&self) -> &R {
&self.inner
}
pub fn read_start_time(&self) -> Option<Instant> {
self.read_start_time
}
pub fn eta(&self) -> Option<Duration> {
self.read_start_time.map(|read_start_time| {
let duration_since_start = Instant::now() - read_start_time;
duration_since_start.div_f64(self.fraction()) - duration_since_start
})
}
pub fn est_total_time(&self) -> Option<Duration> {
self.read_start_time.map(|read_start_time| {
let duration_since_start = Instant::now() - read_start_time;
duration_since_start.div_f64(self.fraction())
})
}
pub fn etc(&self) -> Option<Instant> {
self.read_start_time.map(|read_start_time| {
let duration_since_start = Instant::now() - read_start_time;
read_start_time + duration_since_start.div_f64(self.fraction())
})
}
pub fn bytes_per_sec(&self) -> Option<f64> {
self.read_start_time.map(|read_start_time| {
let since_start = Instant::now() - read_start_time;
(self.total_read as f64)/since_start.as_secs_f64()
})
}
}
impl ReaderWithSize<File> {
pub fn from_path(path: impl Into<PathBuf>) -> Result<Self, std::io::Error> {
let path: PathBuf = path.into();
let file = File::open(path)?;
ReaderWithSize::from_file(file)
}
pub fn from_file(file: File) -> Result<Self, std::io::Error> {
let size = file.metadata()?.len() as usize;
Ok(Self::new(size, file))
}
}
impl<R> Read for ReaderWithSize<R> where R: Read {
fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
let result = self.inner.read(buf);
if let Ok(bytes_read) = result {
self.total_read += bytes_read;
}
if self.read_start_time.is_none() {
self.read_start_time = Some(Instant::now());
}
result
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::io::Cursor;
use std::thread::sleep;
#[test]
fn basic() {
let bytes = "hello".as_bytes();
let mut reader = ReaderWithSize::new(5, Cursor::new(bytes));
assert_eq!(reader.assummed_total_size(), 5);
let mut buf = vec![0];
reader.read_exact(&mut buf).unwrap();
assert_eq!(buf, vec!['h' as u8]);
assert_eq!(reader.total_read(), 1);
assert_eq!(reader.fraction(), 0.2);
let mut buf = vec![0, 0];
reader.read_exact(&mut buf).unwrap();
assert_eq!(buf, vec!['e' as u8, 'l' as u8]);
assert_eq!(reader.total_read(), 3);
assert_eq!(reader.fraction(), 0.6);
let _cursor: &Cursor<&[u8]> = reader.inner();
let _cursor: Cursor<&[u8]> = reader.into_inner();
}
#[test]
fn eta1() {
let start = Instant::now();
let bytes = "hello".as_bytes();
let mut reader = ReaderWithSize::new(5, Cursor::new(bytes));
assert_eq!(reader.eta(), None);
let mut buf = vec![0];
reader.read_exact(&mut buf).unwrap();
sleep(Duration::from_millis(10));
let eta = reader.eta();
let bytes_per_sec = reader.bytes_per_sec();
let etc = reader.etc();
assert!(eta.is_some());
let eta: Duration = eta.unwrap();
assert!(eta >= Duration::from_millis(40));
assert!(40./1000. - eta.as_secs_f64() <= 1.);
assert!(bytes_per_sec.is_some());
let bytes_per_sec: f64 = bytes_per_sec.unwrap();
assert!(bytes_per_sec >= 20.);
assert!(bytes_per_sec < 100.);
assert!(etc.is_some());
let etc: Instant = etc.unwrap();
assert!(etc > start);
assert!(etc < start+Duration::from_secs(1));
}
}