vendor prettyplease

prettyplease-forked/src/ring.rs

@@ -0,0 +1,81 @@
+use std::collections::VecDeque;
+use std::ops::{Index, IndexMut};
+
+pub struct RingBuffer<T> {
+    data: VecDeque<T>,
+    // Abstract index of data[0] in infinitely sized queue
+    offset: usize,
+}
+
+impl<T> RingBuffer<T> {
+    pub fn new() -> Self {
+        RingBuffer {
+            data: VecDeque::new(),
+            offset: 0,
+        }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.data.is_empty()
+    }
+
+    pub fn len(&self) -> usize {
+        self.data.len()
+    }
+
+    pub fn push(&mut self, value: T) -> usize {
+        let index = self.offset + self.data.len();
+        self.data.push_back(value);
+        index
+    }
+
+    pub fn clear(&mut self) {
+        self.data.clear();
+    }
+
+    pub fn index_of_first(&self) -> usize {
+        self.offset
+    }
+
+    pub fn first(&self) -> &T {
+        &self.data[0]
+    }
+
+    pub fn first_mut(&mut self) -> &mut T {
+        &mut self.data[0]
+    }
+
+    pub fn pop_first(&mut self) -> T {
+        self.offset += 1;
+        self.data.pop_front().unwrap()
+    }
+
+    pub fn last(&self) -> &T {
+        self.data.back().unwrap()
+    }
+
+    pub fn last_mut(&mut self) -> &mut T {
+        self.data.back_mut().unwrap()
+    }
+
+    pub fn second_last(&self) -> &T {
+        &self.data[self.data.len() - 2]
+    }
+
+    pub fn pop_last(&mut self) {
+        self.data.pop_back().unwrap();
+    }
+}
+
+impl<T> Index<usize> for RingBuffer<T> {
+    type Output = T;
+    fn index(&self, index: usize) -> &Self::Output {
+        &self.data[index.checked_sub(self.offset).unwrap()]
+    }
+}
+
+impl<T> IndexMut<usize> for RingBuffer<T> {
+    fn index_mut(&mut self, index: usize) -> &mut Self::Output {
+        &mut self.data[index.checked_sub(self.offset).unwrap()]
+    }
+}