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Fix tail -<number> does not work #2747

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Nov 19, 2021
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161 changes: 161 additions & 0 deletions src/uu/tail/src/parse.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,161 @@
// * This file is part of the uutils coreutils package.
// *
// * For the full copyright and license information, please view the LICENSE
// * file that was distributed with this source code.

use std::ffi::OsString;

#[derive(PartialEq, Debug)]
pub enum ParseError {
Syntax,
Overflow,
}
/// Parses obsolete syntax
/// tail -NUM[kmzv] // spell-checker:disable-line
pub fn parse_obsolete(src: &str) -> Option<Result<impl Iterator<Item = OsString>, ParseError>> {
let mut chars = src.char_indices();
if let Some((_, '-')) = chars.next() {
let mut num_end = 0usize;
let mut has_num = false;
let mut last_char = 0 as char;
for (n, c) in &mut chars {
if c.is_numeric() {
has_num = true;
num_end = n;
} else {
last_char = c;
break;
}
}
if has_num {
match src[1..=num_end].parse::<usize>() {
Ok(num) => {
let mut quiet = false;
let mut verbose = false;
let mut zero_terminated = false;
let mut multiplier = None;
let mut c = last_char;
loop {
// not that here, we only match lower case 'k', 'c', and 'm'
match c {
// we want to preserve order
// this also saves us 1 heap allocation
'q' => {
quiet = true;
verbose = false
}
'v' => {
verbose = true;
quiet = false
}
'z' => zero_terminated = true,
'c' => multiplier = Some(1),
'b' => multiplier = Some(512),
'k' => multiplier = Some(1024),
'm' => multiplier = Some(1024 * 1024),
'\0' => {}
_ => return Some(Err(ParseError::Syntax)),
}
if let Some((_, next)) = chars.next() {
c = next
} else {
break;
}
}
let mut options = Vec::new();
if quiet {
options.push(OsString::from("-q"))
}
if verbose {
options.push(OsString::from("-v"))
}
if zero_terminated {
options.push(OsString::from("-z"))
}
if let Some(n) = multiplier {
options.push(OsString::from("-c"));
let num = match num.checked_mul(n) {
Some(n) => n,
None => return Some(Err(ParseError::Overflow)),
};
options.push(OsString::from(format!("{}", num)));
} else {
options.push(OsString::from("-n"));
options.push(OsString::from(format!("{}", num)));
}
Some(Ok(options.into_iter()))
}
Err(_) => Some(Err(ParseError::Overflow)),
}
} else {
None
}
} else {
None
}
}

#[cfg(test)]
mod tests {
use super::*;
fn obsolete(src: &str) -> Option<Result<Vec<String>, ParseError>> {
let r = parse_obsolete(src);
match r {
Some(s) => match s {
Ok(v) => Some(Ok(v.map(|s| s.to_str().unwrap().to_owned()).collect())),
Err(e) => Some(Err(e)),
},
None => None,
}
}
fn obsolete_result(src: &[&str]) -> Option<Result<Vec<String>, ParseError>> {
Some(Ok(src.iter().map(|s| s.to_string()).collect()))
}
#[test]
fn test_parse_numbers_obsolete() {
assert_eq!(obsolete("-5"), obsolete_result(&["-n", "5"]));
assert_eq!(obsolete("-100"), obsolete_result(&["-n", "100"]));
assert_eq!(obsolete("-5m"), obsolete_result(&["-c", "5242880"]));
assert_eq!(obsolete("-1k"), obsolete_result(&["-c", "1024"]));
assert_eq!(obsolete("-2b"), obsolete_result(&["-c", "1024"]));
assert_eq!(obsolete("-1mmk"), obsolete_result(&["-c", "1024"]));
assert_eq!(obsolete("-1vz"), obsolete_result(&["-v", "-z", "-n", "1"]));
assert_eq!(
obsolete("-1vzqvq"), // spell-checker:disable-line
obsolete_result(&["-q", "-z", "-n", "1"])
);
assert_eq!(obsolete("-1vzc"), obsolete_result(&["-v", "-z", "-c", "1"]));
assert_eq!(
obsolete("-105kzm"),
obsolete_result(&["-z", "-c", "110100480"])
);
}
#[test]
fn test_parse_errors_obsolete() {
assert_eq!(obsolete("-5n"), Some(Err(ParseError::Syntax)));
assert_eq!(obsolete("-5c5"), Some(Err(ParseError::Syntax)));
}
#[test]
fn test_parse_obsolete_no_match() {
assert_eq!(obsolete("-k"), None);
assert_eq!(obsolete("asd"), None);
}
#[test]
#[cfg(target_pointer_width = "64")]
fn test_parse_obsolete_overflow_x64() {
assert_eq!(
obsolete("-1000000000000000m"),
Some(Err(ParseError::Overflow))
);
assert_eq!(
obsolete("-10000000000000000000000"),
Some(Err(ParseError::Overflow))
);
}
#[test]
#[cfg(target_pointer_width = "32")]
fn test_parse_obsolete_overflow_x32() {
assert_eq!(obsolete("-42949672960"), Some(Err(ParseError::Overflow)));
assert_eq!(obsolete("-42949672k"), Some(Err(ParseError::Overflow)));
}
}
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