RGBCube/uutils-coreutils
1
Fork 0
mirror of https://github.com/RGBCube/uutils-coreutils synced 2025-07-28 19:47:45 +00:00
Code Issues Activity

uucore: num_parser: Improve scale conversion to i64

Browse source 
It turns out repeatedly calling i64::MAX.into() and i64::MIN.into()
is actually very expensive. Just do the conversion first, and if
it fails, we know why.

Sadly there is still a conversion happening under the hood in
`-exponent + scale`, but that'd need to be fixed in Bigint.

Improves sort -g performance by ~5%.
This commit is contained in:
Nicolas Boichat 2025-06-03 09:21:35 +02:00
parent 8426c1480c
commit edc1e5def6
1 changed files with 6 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

13
src/uucore/src/lib/features/parser/num_parser.rs
View file

@ -465,16 +465,15 @@ fn construct_extended_big_decimal<'a>(
let bd = if scale == 0 && exponent.is_zero() { let bd = if scale == 0 && exponent.is_zero() {
BigDecimal::from_bigint(signed_digits, 0) BigDecimal::from_bigint(signed_digits, 0)
} else if base == Base::Decimal { } else if base == Base::Decimal {
let new_scale = BigInt::from(scale) - exponent; let new_scale = -exponent + scale;
// BigDecimal "only" supports i64 scale. // BigDecimal "only" supports i64 scale.
// Note that new_scale is a negative exponent: large value causes an underflow, small value an overflow. // Note that new_scale is a negative exponent: large positive value causes an underflow, large negative values an overflow.
if new_scale > i64::MAX.into() { if let Some(new_scale) = new_scale.to_i64() {
return Err(make_error(false, negative)); BigDecimal::from_bigint(signed_digits, new_scale)
} else if new_scale < i64::MIN.into() { } else {
return Err(make_error(true, negative)); return Err(make_error(new_scale.is_negative(), negative));
} }
BigDecimal::from_bigint(signed_digits, new_scale.to_i64().unwrap())
} else if base == Base::Hexadecimal { } else if base == Base::Hexadecimal {
// pow "only" supports u32 values, just error out if given more than 2**32 fractional digits. // pow "only" supports u32 values, just error out if given more than 2**32 fractional digits.
if scale > u32::MAX.into() { if scale > u32::MAX.into() {