Merge pull request uutils#8821 from cakebaker/uucore_parse_time_very_small_number

uucore/parse_time: return 1ns for small numbers

Author: sylvestre

src/uucore/src/lib/features/parser/parse_time.rs

@@ -13,9 +13,9 @@ use crate::{
  extendedbigdecimal::ExtendedBigDecimal,
  parser::num_parser::{self, ExtendedParserError, ParseTarget},
 };
-use num_traits::Signed;
 use num_traits::ToPrimitive;
 use num_traits::Zero;
+use num_traits::{FromPrimitive, Signed};
 use std::time::Duration;
 
 /// Parse a duration from a string.
@@ -86,6 +86,10 @@ pub fn from_str(string: &str, allow_suffixes: bool) -> Result<Duration, String>
  // potentially expensive to-nanoseconds conversion
  return Ok(Duration::MAX);
  }
+ // early return if number is too small (< 1 ns)
+ if !bd.is_zero() && bd < bigdecimal::BigDecimal::from_f64(0.0000000001).unwrap() {
+ return Ok(NANOSECOND_DURATION);
+ }
  bd
  }
  ExtendedBigDecimal::MinusZero => 0.into(),
@@ -165,6 +169,10 @@ mod tests {
  from_str("1e-92233720368547758080", false),
  Ok(NANOSECOND_DURATION)
  );
+ assert_eq!(
+ from_str("0x6p-4376646810043701", false),
+ Ok(NANOSECOND_DURATION)
+ );
  // nanoseconds underflow (in Duration, false)
  assert_eq!(from_str("0.0000000001", false), Ok(NANOSECOND_DURATION));
  assert_eq!(from_str("1e-10", false), Ok(NANOSECOND_DURATION));