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Using macro to avoid performance hit (thanks LingMan)

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gilescope 2022-03-26 14:53:56 +00:00
parent e93d03b28a
commit d27454eda5
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1 changed files with 13 additions and 7 deletions
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20
library/core/src/num/mod.rs
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@ -1078,14 +1078,20 @@ fn from_str_radix<T: FromStrRadixHelper>(src: &str, radix: u32) -> Result<T, Par
// `u8::MAX` is `ff` - any str of len 2 is guaranteed to not overflow.
// `i8::MAX` is `7f` - only a str of len 1 is guaranteed to not overflow.
unsafe {
let unchecked_additive_op =
if is_positive { T::unchecked_add } else { T::unchecked_sub };
for &c in digits {
result = result.unchecked_mul(radix);
let x = (c as char).to_digit(radix).ok_or(PIE { kind: InvalidDigit })?;
result = unchecked_additive_op(&result, x);
macro_rules! run_loop {
($unchecked_additive_op:ident) => {
for &c in digits {
result = result.unchecked_mul(radix);
let x = (c as char).to_digit(radix).ok_or(PIE { kind: InvalidDigit })?;
result = T::$unchecked_additive_op(&result, x);
}
};
}
if is_positive {
run_loop!(unchecked_add)
} else {
run_loop!(unchecked_sub)
};
}
} else {
let additive_op = if is_positive { T::checked_add } else { T::checked_sub };