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iter: use Option::map() in struct Iterater::map()

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Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
This commit is contained in:
Lai Jiangshan 2015-03-02 17:32:16 +08:00
parent 1576142495
commit cd65156514
1 changed files with 3 additions and 16 deletions
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19
src/libcore/iter.rs
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@ -1565,24 +1565,13 @@ pub struct Map<I, F> {
f: F,
}
impl<I: Iterator, F, B> Map<I, F> where F: FnMut(I::Item) -> B {
#[inline]
fn do_map(&mut self, elt: Option<I::Item>) -> Option<B> {
match elt {
Some(a) => Some((self.f)(a)),
_ => None
}
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<B, I: Iterator, F> Iterator for Map<I, F> where F: FnMut(I::Item) -> B {
type Item = B;
#[inline]
fn next(&mut self) -> Option<B> {
let next = self.iter.next();
self.do_map(next)
self.iter.next().map(|a| (self.f)(a))
}
#[inline]
@ -1597,8 +1586,7 @@ impl<B, I: DoubleEndedIterator, F> DoubleEndedIterator for Map<I, F> where
{
#[inline]
fn next_back(&mut self) -> Option<B> {
let next = self.iter.next_back();
self.do_map(next)
self.iter.next_back().map(|a| (self.f)(a))
}
}
@ -1613,8 +1601,7 @@ impl<B, I: RandomAccessIterator, F> RandomAccessIterator for Map<I, F> where
#[inline]
fn idx(&mut self, index: usize) -> Option<B> {
let elt = self.iter.idx(index);
self.do_map(elt)
self.iter.idx(index).map(|a| (self.f)(a))
}
}