forked from bonsai/harakit
96 lines
2.6 KiB
Rust
96 lines
2.6 KiB
Rust
/*
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* Copyright (c) 2024 DTB <trinity@trinity.moe>
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*
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* This program is free software: you can redistribute it and/or modify it under
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* the terms of the GNU Affero General Public License as published by the Free
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* Software Foundation, either version 3 of the License, or (at your option) any
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* later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see https://www.gnu.org/licenses/.
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*/
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use std::{
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env::args,
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io::{ stdin, stdout, Error, ErrorKind, Read, Write },
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process::ExitCode,
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vec::Vec
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};
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extern crate getopt;
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use getopt::GetOpt;
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extern crate sysexits;
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use sysexits::{ EX_IOERR, EX_OK, EX_USAGE };
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extern crate strerror;
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use strerror::StrError;
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fn err(s: &str, e: Error) { eprintln!("{}: {}", s, e.strerror()); }
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fn usage(s: &str) -> ExitCode {
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eprintln!("Usage: {} [-f] [-w word_size]", s);
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ExitCode::from(EX_USAGE as u8)
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}
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fn main() -> ExitCode {
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let argv = args().collect::<Vec<String>>();
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let mut buf: Vec<u8> = Vec::new(); // holds the sequence getting swabbed
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let mut input = stdin();
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let mut output = stdout().lock();
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let mut force = false;
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let mut wordsize: usize = 2; // default; mimics dd(1p) conv=swab
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while let Some(opt) = argv.getopt("fw:") {
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match opt.opt() {
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Ok("f") => force = true,
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Ok("w") => { // sets new sequence length
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if let Some(arg) = opt.arg() {
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match arg.parse::<usize>() {
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// an odd sequence length is nonsensical
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Ok(w) if w % 2 == 0 => { wordsize = w; () },
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_ => { return usage(&argv[0]); },
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}
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}
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},
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_ => { return usage(&argv[0]); }
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}
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}
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buf.resize(wordsize, 0);
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loop {
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match input.read(&mut buf) {
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Ok(0) => break ExitCode::from(EX_OK as u8), // read nothing; bye
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Ok(v) if v == wordsize => { // read full block; swab
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let (left, right) = buf.split_at(v/2);
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if let Err(e) = output.write(&right)
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.and_then(|_| output.write(&left)) {
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err(&argv[0], e);
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break EX_IOERR // write error
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}
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},
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Ok(v) => { // partial read; partially write
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if let Err(e) = output.write(&buf[..v]) {
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err(&argv[0], e);
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break EX_IOERR // write error
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}
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},
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Err(e) if e.kind() == ErrorKind::Interrupted && force => continue,
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Err(e) => {
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err(&argv[0], e);
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break EX_IOERR // read error (or signal)
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}
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}
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}
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}
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