diff --git a/src/lib.rs b/src/lib.rs index a592e79..3d1ba28 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -1 +1,2 @@ pub mod first; +pub mod second; diff --git a/src/second.rs b/src/second.rs new file mode 100644 index 0000000..d571b69 --- /dev/null +++ b/src/second.rs @@ -0,0 +1,199 @@ +pub struct List { + head: Link, +} + +type Link = Option>>; + +struct Node { + elem: T, + next: Link, +} + +pub struct Iter<'a, T: 'a> { + next: Option<&'a Node>, +} + +pub struct IterMut<'a, T: 'a> { + next: Option<&'a mut Node>, +} + +pub struct IntoIter(List); + +impl List { + pub fn new() -> Self { + List { head: None } + } + + pub fn push(&mut self, elem: T) { + let new_node = Box::new(Node { + elem, + next: self.head.take(), + }); + + self.head = Some(new_node); + } + + pub fn pop(&mut self) -> Option { + self.head.take().map(|node| { + let node = *node; + self.head = node.next; + node.elem + }) + } + + pub fn peek(&self) -> Option<&T> { + self.head.as_ref().map(|node| { + &node.elem + }) + } + + pub fn peek_mut(&mut self) -> Option<&mut T> { + self.head.as_mut().map(|node| { + &mut node.elem + }) + } + + pub fn iter(&self) -> Iter { + Iter { next: self.head.as_ref().map(|node| &**node) } + } + + pub fn iter_mut(&mut self) -> IterMut { + IterMut { next: self.head.as_mut().map(|node| &mut **node) } + } + + pub fn into_iter(self) -> IntoIter { + IntoIter(self) + } +} + +impl<'a, T> Iterator for Iter<'a, T> { + type Item = &'a T; + + fn next(&mut self) -> Option { + self.next.map(|node| { + self.next = node.next.as_ref().map(|node| &**node); + &node.elem + }) + } +} + +impl<'a, T> Iterator for IterMut<'a, T> { + type Item = &'a mut T; + + fn next(&mut self) -> Option { + self.next.take().map(|node| { + self.next = node.next.as_mut().map(|node| &mut **node); + &mut node.elem + }) + } +} + +impl Iterator for IntoIter { + type Item = T; + fn next(&mut self) -> Option { + // access fields of a tuple struct numerically + self.0.pop() + } +} + +impl Drop for List { + fn drop(&mut self) { + let mut cur_link = self.head.take(); + + while let Some(mut boxed_node) = cur_link { + cur_link = boxed_node.next.take(); + } + } +} + +#[cfg(test)] +mod test { + use super::List; + + #[test] + fn basics() { + let mut list = List::new(); + + // Check empty list behaves right + assert_eq!(list.pop(), None); + + // Populate list + list.push(1); + list.push(2); + list.push(3); + + // Check normal removal + assert_eq!(list.pop(), Some(3)); + assert_eq!(list.pop(), Some(2)); + + // Push some more just to make sure nothing's corrupted + list.push(4); + list.push(5); + + // Check normal removal + assert_eq!(list.pop(), Some(5)); + assert_eq!(list.pop(), Some(4)); + + // Check exhaustion + assert_eq!(list.pop(), Some(1)); + assert_eq!(list.pop(), None); + } + + #[test] + fn peek() { + let mut list = List::new(); + assert_eq!(list.peek(), None); + assert_eq!(list.peek_mut(), None); + + list.push(1); + list.push(2); + list.push(3); + + assert_eq!(list.peek(), Some(&3)); + assert_eq!(list.peek_mut(), Some(&mut 3)); + } + + #[test] + fn iter() { + let mut list = List::new(); + + list.push(1); + list.push(2); + list.push(3); + + let mut iter = list.iter(); + assert_eq!(iter.next(), Some(&3)); + assert_eq!(iter.next(), Some(&2)); + assert_eq!(iter.next(), Some(&1)); + } + + #[test] + fn iter_mut() { + let mut list = List::new(); + + list.push(1); + list.push(2); + list.push(3); + + let mut iter = list.iter_mut(); + assert_eq!(iter.next(), Some(&mut 3)); + assert_eq!(iter.next(), Some(&mut 2)); + assert_eq!(iter.next(), Some(&mut 1)); + } + + #[test] + fn into_iter() { + let mut list = List::new(); + + list.push(1); + list.push(2); + list.push(3); + + let mut iter = list.into_iter(); + assert_eq!(iter.next(), Some(3)); + assert_eq!(iter.next(), Some(2)); + assert_eq!(iter.next(), Some(1)); + } + + +}