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forked from bonsai/harakit
coreutils/bin/swab/swab.rs
2024-03-31 00:12:21 +05:45

91 lines
2.3 KiB
Rust

/*
* Copyright (c) 2024 DTB <trinity@trinity.moe>
* SPDX-License-Identifier: AGPL-3.0-or-later
*
* This program is free software: you can redistribute it and/or modify it under
* the terms of the GNU Affero General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
* details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see https://www.gnu.org/licenses/.
*/
use std::{
env::args,
io::{ stdin, stdout, Error, ErrorKind, Read, Write },
process::ExitCode,
vec::Vec
};
extern crate getopt;
use getopt::{ Opt, Parser };
extern crate sysexits;
use sysexits::{ EX_OK, EX_OSERR, EX_USAGE };
fn oserr(s: &str, e: Error) -> ExitCode {
eprintln!("{}: {}", s, e);
ExitCode::from(EX_OSERR as u8)
}
fn usage(s: &str) -> ExitCode {
eprintln!("Usage: {} (-f) (-w [wordsize])", s);
ExitCode::from(EX_USAGE as u8)
}
fn main() -> ExitCode {
let argv = args().collect::<Vec<String>>();
let mut buf: Vec<u8> = Vec::new();
let mut input = stdin();
let mut output = stdout().lock();
let mut opts = Parser::new(&argv, "fw:");
let mut force = false;
let mut wordsize: usize = 2;
loop {
match opts.next() {
None => break,
Some(opt) =>
match opt {
Ok(Opt('f', None)) => force = true,
Ok(Opt('w', Some(arg))) => {
match arg.parse::<usize>() {
Ok(w) if w % 2 == 0 => { wordsize = w; () },
_ => { return usage(&argv[0]); },
}
},
_ => { return usage(&argv[0]); }
}
}
}
buf.resize(wordsize, 0);
loop {
match input.read(&mut buf) {
Ok(0) => break ExitCode::from(EX_OK as u8),
Ok(v) if v == wordsize => {
let (left, right) = buf.split_at(v/2);
if let Err(e) = output.write(&right)
.and_then(|_| output.write(&left)) {
break oserr(&argv[0], e)
}
},
Ok(v) => {
if let Err(e) = output.write(&buf[..v]) {
break oserr(&argv[0], e)
}
},
Err(e) if e.kind() == ErrorKind::Interrupted && force => continue,
Err(e) => break oserr(&argv[0], e)
}
}
}