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use std::fmt;
use std::fs::File;
use std::io;
use std::io::{BufRead, BufReader, Read, Write};
use std::path::PathBuf;
use std::process;
pub struct InputReader<'a>(Box<dyn BufRead + 'a>);
impl<'a> Read for InputReader<'a> {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
self.0.read(buf)
}
}
impl<'a> BufRead for InputReader<'a> {
fn fill_buf(&mut self) -> io::Result<&[u8]> {
self.0.fill_buf()
}
fn consume(&mut self, amt: usize) {
self.0.consume(amt)
}
}
pub enum Input {
Stdin(io::Stdin),
File(PathBuf),
}
impl Input {
pub fn from<P>(path: Option<P>) -> Self
where
P: Into<PathBuf>,
{
match path {
Some(path) => Input::File(path.into()),
None => Input::Stdin(io::stdin()),
}
}
pub fn buf_read(&self) -> io::Result<InputReader> {
match self {
Input::Stdin(ref stdin) => Result::Ok(InputReader(Box::new(stdin.lock()))),
Input::File(ref path) => File::open(path)
.map(BufReader::new)
.map(Box::new)
.map(|r| InputReader(r)),
}
}
}
pub enum Output {
Stdout(io::Stdout),
File(PathBuf),
}
impl Output {
pub fn from<P>(path: Option<P>) -> Self
where
P: Into<PathBuf>,
{
match path {
Some(path) => Output::File(path.into()),
None => Output::Stdout(io::stdout()),
}
}
pub fn write<'a>(&'a self) -> io::Result<Box<dyn Write + 'a>> {
match self {
Output::Stdout(ref stdout) => Result::Ok(Box::new(stdout.lock())),
Output::File(ref path) => Result::Ok(Box::new(File::create(path)?)),
}
}
}
pub trait OrExit<R, S>
where
S: AsRef<str>,
{
fn or_exit(self, message: S, code: i32) -> R;
}
impl<R, S, E> OrExit<R, S> for Result<R, E>
where
S: AsRef<str>,
E: fmt::Display,
{
fn or_exit(self, description: S, code: i32) -> R {
match self {
Result::Ok(val) => val,
Result::Err(err) => {
eprintln!("{}: {}", description.as_ref(), err);
process::exit(code);
}
}
}
}
impl<R, S> OrExit<R, S> for Option<R>
where
S: AsRef<str>,
{
fn or_exit(self, description: S, code: i32) -> R {
match self {
Some(val) => val,
None => {
eprintln!("{}", description.as_ref());
process::exit(code);
}
}
}
}