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Fix just a few stacked borrow issues, and improve extend performance #111

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Merged
merged 3 commits into from
Nov 25, 2018
Merged

Fix just a few stacked borrow issues, and improve extend performance #111

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91e88a4
FEAT: Simplify stack guard in extend
bluss Nov 25, 2018
2312827
TEST: Update benchmark for extend_from_slice
bluss Nov 25, 2018
f40e708
FIX: In truncate, don't access self while holding raw pointer derived…
bluss Nov 25, 2018
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3 changes: 2 additions & 1 deletion benches/extend.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@ extern crate arrayvec;
use arrayvec::ArrayVec;

use bencher::Bencher;
use bencher::black_box;

fn extend_with_constant(b: &mut Bencher) {
let mut v = ArrayVec::<[u8; 512]>::new();
Expand Down Expand Up @@ -33,7 +34,7 @@ fn extend_with_slice(b: &mut Bencher) {
let data = [1; 512];
b.iter(|| {
v.clear();
v.extend(data.iter().cloned());
v.extend(black_box(data.iter()).cloned());
v[0]
});
b.bytes = v.capacity() as u64;
Expand Down
14 changes: 7 additions & 7 deletions src/lib.rs
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Expand Up @@ -461,11 +461,11 @@ impl<A: Array> ArrayVec<A> {
/// array.truncate(4);
/// assert_eq!(&array[..], &[1, 2, 3]);
/// ```
pub fn truncate(&mut self, len: usize) {
pub fn truncate(&mut self, new_len: usize) {
unsafe {
if len < self.len() {
let tail: *mut [_] = &mut self[len..];
self.set_len(len);
if new_len < self.len() {
let tail: *mut [_] = &mut self[new_len..];
self.len = Index::from(new_len);
ptr::drop_in_place(tail);
}
}
Expand Down Expand Up @@ -890,10 +890,10 @@ impl<A: Array> Extend<A::Item> for ArrayVec<A> {
// We update the length to handle panic in the iteration of the
// user's iterator, without dropping any elements on the floor.
let mut guard = ScopeExitGuard {
value: self,
value: &mut self.len,
data: len,
f: |&len, self_| {
self_.set_len(len)
f: move |&len, self_len| {
**self_len = Index::from(len);
}
};
for elt in iter.into_iter().take(take) {
Expand Down