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use std::io::{BufReader, BufWriter, Read, Write};
pub use crate::cli::{Cli, Opts};
pub use crate::error::{Error, Result};
pub use crate::input::Input;
mod cli;
mod error;
mod input;
pub const HELP: &str = r#"Usage: cat [OPTION]... [FILE]...
Concatenate FILE(s) to standard output.
With no FILE, or when FILE is -, read standard input.
-A, --show-all equivalent to -vET
-b, --number-nonblank number nonempty output lines, overrides -n
-e equivalent to -vE
-E, --show-ends display $ at end of each line
-n, --number number all output lines
-s, --squeeze-blank suppress repeated empty output lines
-t equivalent to -vT
-T, --show-tabs display TAB characters as ^I
-u (ignored)
-v, --show-nonprinting use ^ and M- notation, except for LFD and TAB
--help display this help and exit
--version output version information and exit
Examples:
cat f - g Output f's contents, then standard input, then g's contents.
cat Copy standard input to standard output."#;
const UNKNOWN_CHAR: &[u8; 2] = b"^?";
pub fn run(cli: Cli) -> Result<()> {
let stdout = std::io::stdout();
let mut writer = stdout.lock();
for file in cli.files.into_iter() {
process_input(&mut file.reader()?, &mut writer, &cli.opts)?;
}
Ok(())
}
fn process_input(reader: impl Read, writer: &mut impl Write, opts: &Opts) -> Result<()> {
let mut reader = BufReader::new(reader);
let mut writer = BufWriter::new(writer);
let mut nonblank_line_nr = 0;
let mut buf = Vec::new();
reader.read_to_end(&mut buf)?;
for (index, arr) in buf.split(|c| *c == b'\n').enumerate() {
if arr.is_empty() && opts.squeeze_blank {
continue;
}
let mut line = Vec::new();
for c in arr {
let parsed = match *c {
b'\t' if opts.show_tabs => b"^I".to_vec(),
b'\t' => b"\t".to_vec(),
c if opts.show_nonprinting => parse_nonprinting_char(c),
c => [c].to_vec(),
};
line.extend(parsed)
}
if opts.show_ends {
line.push(b'$');
}
line.push(b'\n');
if opts.number_nonblank {
if !line.is_empty() {
nonblank_line_nr += 1;
write!(writer, "{:>6} ", nonblank_line_nr)?;
}
} else if opts.number {
write!(writer, "{:>6} ", index + 1)?;
}
writer.write_all(&line)?
}
Ok(())
}
fn parse_nonprinting_char(mut c: u8) -> Vec<u8> {
let mut buf = Vec::new();
if c >= 128 {
c -= 128;
buf.extend(b"M-");
}
match c {
c @ 0..=31 => buf.extend([b'^', c + 64]),
c @ 32..=126 => buf.push(c),
127.. => buf.extend(UNKNOWN_CHAR),
};
buf
}
#[cfg(test)]
mod test {
use super::*;
use std::process::{Command, Stdio};
#[test]
fn test_process_input() {
let input = (0..255_u8)
.map(|i| format!("{}", i as char))
.collect::<Vec<String>>()
.join("\n");
let cat_child = Command::new("cat")
.arg("-")
.arg("-v")
.stdin(Stdio::piped())
.stdout(Stdio::piped())
.spawn()
.unwrap();
cat_child
.stdin
.as_ref()
.unwrap()
.write_all(input.as_bytes())
.unwrap();
let cat_output = cat_child.wait_with_output().unwrap();
let cat_result = String::from_utf8(cat_output.stdout).unwrap();
let opts = Opts {
show_nonprinting: true,
..Default::default()
};
let mut writer = Vec::new();
process_input(input.as_bytes(), &mut writer, &opts).unwrap();
let result = String::from_utf8(writer).unwrap();
cat_result
.lines()
.zip(result.lines())
.for_each(|(c_cat, c)| assert_eq!(c_cat, c));
}
}
|
