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collections: minimize code that's in unsafe blocks

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This changes Vec::from_slice to call unsafe_push_all_clone
directly to avoid doing an unnecessary reserve_additional call
This commit is contained in:
Erick Tryzelaar 2014-07-07 09:11:03 -07:00
parent 7d3899430b
commit e2d107c397
1 changed files with 23 additions and 23 deletions
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46
src/libcollections/vec.rs
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@ -198,7 +198,13 @@ impl<T: Clone> Vec<T> {
#[inline]
pub fn from_slice(values: &[T]) -> Vec<T> {
let mut vector = Vec::with_capacity(values.len());
vector.push_all(values);
// Directly call `unsafe_push_all_clone` so we can skip a call to
// `reserve_addtional`.
unsafe {
unsafe_push_all_clone(&mut vector, values);
}
vector
}
@ -240,8 +246,9 @@ impl<T: Clone> Vec<T> {
/// ```
#[inline]
pub fn push_all(&mut self, other: &[T]) {
self.reserve_additional(other.len());
unsafe {
self.reserve_additional(other.len());
unsafe_push_all_clone(self, other)
}
}
@ -323,31 +330,24 @@ impl<T: Clone> Vec<T> {
#[unstable]
impl<T:Clone> Clone for Vec<T> {
fn clone(&self) -> Vec<T> {
unsafe {
let mut vector = Vec::with_capacity(self.len);
unsafe_push_all_clone(&mut vector, self.as_slice());
vector
}
Vec::from_slice(self.as_slice())
}
fn clone_from(&mut self, other: &Vec<T>) {
unsafe {
// drop anything in self that will not be overwritten
if self.len() > other.len() {
self.truncate(other.len())
}
// reuse the contained values' allocations/resources.
for (place, thing) in self.mut_iter().zip(other.iter()) {
place.clone_from(thing)
}
// self.len <= other.len due to the truncate above, so the
// slice here is always in-bounds.
let slice = other.slice_from(self.len());
self.reserve_additional(slice.len());
unsafe_push_all_clone(self, slice)
// drop anything in self that will not be overwritten
if self.len() > other.len() {
self.truncate(other.len())
}
// reuse the contained values' allocations/resources.
for (place, thing) in self.mut_iter().zip(other.iter()) {
place.clone_from(thing)
}
// self.len <= other.len due to the truncate above, so the
// slice here is always in-bounds.
let slice = other.slice_from(self.len());
self.push_all(slice);
}
}