user0/rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

dlist: Simplify match clauses to use Option methods

Browse source 
Make the core Deque implementation a bit simpler by using Option methods
when we simply map on a Some value, and deduplicate some common lines.
This commit is contained in:
blake2-ppc 2013-07-21 19:31:40 +02:00
parent 60cb9c003c
commit 5336bdcab1
1 changed files with 33 additions and 65 deletions
Download patch file Download diff file Expand all files Collapse all files

98
src/libextra/dlist.rs
View file

@ -175,21 +175,12 @@ impl<T> Deque<T> for DList<T> {
///
/// O(1)
fn pop_back(&mut self) -> Option<T> {
match self.list_tail.resolve() {
None => None,
Some(tail) => {
self.length -= 1;
let tail_own = match tail.prev.resolve() {
None => {
self.list_tail = Rawlink::none();
self.list_head.take_unwrap()
},
Some(tail_prev) => {
self.list_tail = tail.prev;
tail_prev.next.take_unwrap()
}
};
Some(tail_own.value)
do self.list_tail.resolve().map_consume |tail| {
self.length -= 1;
self.list_tail = tail.prev;
match tail.prev.resolve() {
None => self.list_head.take_unwrap().value,
Some(tail_prev) => tail_prev.next.take_unwrap().value
}
}
}
@ -217,21 +208,13 @@ impl<T> Deque<T> for DList<T> {
///
/// O(1)
fn pop_front(&mut self) -> Option<T> {
match self.list_head.take() {
None => None,
Some(old_head) => {
self.length -= 1;
match *old_head {
Node{value: value, next: Some(next), prev: _} => {
self.list_head = link_with_prev(next, Rawlink::none());
Some(value)
}
Node{value: value, next: None, prev: _} => {
self.list_tail = Rawlink::none();
Some(value)
}
}
do self.list_head.take().map_consume |~Node{value, next, _}| {
self.length -= 1;
match next {
Some(node) => self.list_head = link_with_prev(node, Rawlink::none()),
None => self.list_tail = Rawlink::none()
}
value
}
}
}
@ -251,7 +234,7 @@ impl<T> DList<T> {
None => *self = other,
Some(tail) => {
match other {
DList{list_head: None, list_tail: _, length: _} => return,
DList{list_head: None, _} => return,
DList{list_head: Some(node), list_tail: o_tail, length: o_length} => {
tail.next = link_with_prev(node, self.list_tail);
self.list_tail = o_tail;
@ -377,13 +360,10 @@ impl<'self, A> Iterator<&'self A> for DListIterator<'self, A> {
if self.nelem == 0 {
return None;
}
match *self.head {
None => None,
Some(ref head) => {
self.nelem -= 1;
self.head = &head.next;
Some(&head.value)
}
do self.head.map |head| {
self.nelem -= 1;
self.head = &head.next;
&head.value
}
}
@ -399,13 +379,10 @@ impl<'self, A> DoubleEndedIterator<&'self A> for DListIterator<'self, A> {
if self.nelem == 0 {
return None;
}
match self.tail.resolve() {
None => None,
Some(prev) => {
self.nelem -= 1;
self.tail = prev.prev;
Some(&prev.value)
}
do self.tail.resolve().map_consume |prev| {
self.nelem -= 1;
self.tail = prev.prev;
&prev.value
}
}
}
@ -416,16 +393,13 @@ impl<'self, A> Iterator<&'self mut A> for MutDListIterator<'self, A> {
if self.nelem == 0 {
return None;
}
match self.head.resolve() {
None => None,
Some(next) => {
self.nelem -= 1;
self.head = match next.next {
Some(ref mut node) => Rawlink::some(&mut **node),
None => Rawlink::none(),
};
Some(&mut next.value)
}
do self.head.resolve().map_consume |next| {
self.nelem -= 1;
self.head = match next.next {
Some(ref mut node) => Rawlink::some(&mut **node),
None => Rawlink::none(),
};
&mut next.value
}
}
@ -441,13 +415,10 @@ impl<'self, A> DoubleEndedIterator<&'self mut A> for MutDListIterator<'self, A>
if self.nelem == 0 {
return None;
}
match self.tail.resolve() {
None => None,
Some(prev) => {
self.nelem -= 1;
self.tail = prev.prev;
Some(&mut prev.value)
}
do self.tail.resolve().map_consume |prev| {
self.nelem -= 1;
self.tail = prev.prev;
&mut prev.value
}
}
}
@ -484,10 +455,7 @@ impl<'self, A> ListInsertion<A> for MutDListIterator<'self, A> {
#[inline]
fn peek_next<'a>(&'a mut self) -> Option<&'a mut A> {
match self.head.resolve() {
None => None,
Some(head) => Some(&mut head.value),
}
self.head.resolve().map_consume(|head| &mut head.value)
}
}