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next_power_of_two panic on overflow

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This commit is contained in:
Irfan Hudda
2017-04-19 23:59:43 +05:30
parent f7c641b8b6
commit 04e9c20228
1 changed files with 8 additions and 2 deletions
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10
src/libcore/num/mod.rs
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@@ -2345,7 +2345,11 @@ macro_rules! uint_impl {
pub fn next_power_of_two(self) -> Self {
let bits = size_of::<Self>() * 8;
let one: Self = 1;
one << ((bits - self.wrapping_sub(one).leading_zeros() as usize) % bits)
if self == 0 {
1
} else {
one << (bits - self.wrapping_sub(one).leading_zeros() as usize)
}
}
/// Returns the smallest power of two greater than or equal to `n`. If
@@ -2363,7 +2367,9 @@ macro_rules! uint_impl {
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn checked_next_power_of_two(self) -> Option<Self> {
let npot = self.next_power_of_two();
let bits = size_of::<Self>() * 8;
let one: Self = 1;
let npot = one << ((bits - self.wrapping_sub(one).leading_zeros() as usize) % bits);
if npot >= self {
Some(npot)
} else {