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#[cfg(test)]
#[macro_use] extern crate hex_literal;
extern crate digest;
use digest::Digest;
use digest::generic_array::GenericArray;
use std::io::{self, Read, Write, ErrorKind};
const DEFAULT_BUF_SIZE: usize = 4 * 1024 * 1024;
pub fn copy_and_hash<R: ?Sized, W: ?Sized, H>(reader: &mut R, writer: &mut W) -> io::Result<(u64, GenericArray<u8, H::OutputSize>)>
where R: Read, W: Write, H: Digest
{
let mut buf = vec![0; DEFAULT_BUF_SIZE];
let mut hasher = H::new();
let mut written = 0;
loop {
let len = match reader.read(&mut buf) {
Ok(0) => return Ok((written, hasher.result())),
Ok(len) => len,
Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
Err(e) => return Err(e),
};
hasher.input(&buf[..len]);
writer.write_all(&buf[..len])?;
written += len as u64;
}
}
#[cfg(test)]
mod tests {
use super::copy_and_hash;
extern crate sha2;
use std::fs::File;
#[test]
fn test_copies_small_things() {
let result = hex!("26c6394cd46693652def622def991758b4c611c4029c2e47dc8c6504f4be600f");
let len = 17;
let input = "butts butts butts";
let mut output = vec![];
let ret = copy_and_hash::<_, _, sha2::Sha256>(&mut input.as_bytes(), &mut output).unwrap();
assert_eq!(ret.0, len);
assert_eq!(ret.1.as_slice(), result);
assert_eq!(String::from_utf8(output).unwrap(), input);
}
#[test]
fn test_copies_large_things() {
let result = hex!("87bcb5058da1531811646857b8d5684429480ef938fd0b143408c42c2fe8e974");
let len = 84084;
let mut input = File::open("test/many_butts").unwrap();
let mut output = vec![];
let ret = copy_and_hash::<_, _, sha2::Sha256>(&mut input, &mut output).unwrap();
assert_eq!(ret.0, len);
assert_eq!(ret.1.as_slice(), result);
}
#[test]
fn test_copies_things_spanning_multiple_blocks() {
let result = hex!("4c34caef17ee3d709ea9f3c964a79722f79118cd00869a340c3bdf1bb38375c3");
let len = 7020351;
let mut input = File::open("test/extremely_many_butts").unwrap();
let mut output = vec![];
let ret = copy_and_hash::<_, _, sha2::Sha256>(&mut input, &mut output).unwrap();
assert_eq!(ret.0, len);
assert_eq!(ret.1.as_slice(), result);
}
}