nice: Refactor clamp

Author: oech3

src/uu/nice/src/nice.rs

@@ -9,6 +9,7 @@ use clap::{Arg, ArgAction, Command};
 use libc::PRIO_PROCESS;
 use std::ffi::OsString;
 use std::io::{Error, ErrorKind, Write};
+use std::num::IntErrorKind;
 use std::os::unix::process::CommandExt;
 use std::process;
 
@@ -126,28 +127,16 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
             }
             match nstr.parse::<i32>() {
                 Ok(num) => num,
-                Err(e) => {
-                    // clamp huge values
-                    let trimmed = nstr.trim();
-                    let mut chars = trimmed.chars();
-                    let first = chars.next();
-                    let is_valid_number = (first.is_some_and(|c| c.is_ascii_digit())
-                        || first == Some('-')
-                        || first == Some('+'))
-                        && chars.all(|c| c.is_ascii_digit());
-                    if is_valid_number {
-                        if first == Some('-') {
-                            i32::MIN
-                        } else {
-                            i32::MAX
-                        }
-                    } else {
+                Err(e) => match e.kind() {
+                    IntErrorKind::PosOverflow => i32::MAX,
+                    IntErrorKind::NegOverflow => i32::MIN,
+                    _ => {
                         return Err(USimpleError::new(
                             125,
                             translate!("nice-error-invalid-number", "value" => nstr.clone(), "error" => e),
                         ));
                     }
-                }
+                },
             }
         }
         None => {

tests/by-util/test_nice.rs

@@ -108,6 +108,7 @@ fn test_nice_huge_negative() {
     new_ucmd!().args(&["-n", "-9999999999", "true"]).succeeds(); // permission denied
 }
 
+#[test]
 fn test_sign_middle() {
     new_ucmd!().args(&["-n", "-2+4", "true"]).fails();
 }