vec/raw: Simplify `RawVec::grow` (#392)

pull/395/head
nicoo 2 years ago committed by GitHub
parent 03fa5be459
commit 960d610e7f
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GPG Key ID: 4AEE18F83AFDEB23

@ -28,18 +28,13 @@ impl<T> RawVec<T> {
}
fn grow(&mut self) {
let (new_cap, new_layout) = if self.cap == 0 {
(1, Layout::array::<T>(1).unwrap())
} else {
// This can't overflow because we ensure self.cap <= isize::MAX.
let new_cap = 2 * self.cap;
// Layout::array checks that the number of bytes is <= usize::MAX,
// but this is redundant since old_layout.size() <= isize::MAX,
// so the `unwrap` should never fail.
let new_layout = Layout::array::<T>(new_cap).unwrap();
(new_cap, new_layout)
};
// This can't overflow because we ensure self.cap <= isize::MAX.
let new_cap = if self.cap == 0 { 1 } else { 2 * self.cap };
// Layout::array checks that the number of bytes is <= usize::MAX,
// but this is redundant since old_layout.size() <= isize::MAX,
// so the `unwrap` should never fail.
let new_layout = Layout::array::<T>(new_cap).unwrap();
// Ensure that the new allocation doesn't exceed `isize::MAX` bytes.
assert!(new_layout.size() <= isize::MAX as usize, "Allocation too large");

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