1  /* This file is part of DarkFi (https://dark.fi)
 2   *
 3   * Copyright (C) 2020-2025 Dyne.org foundation
 4   *
 5   * This program is free software: you can redistribute it and/or modify
 6   * it under the terms of the GNU Affero General Public License as
 7   * published by the Free Software Foundation, either version 3 of the
 8   * License, or (at your option) any later version.
 9   *
10   * This program is distributed in the hope that it will be useful,
11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   * GNU Affero General Public License for more details.
14   *
15   * You should have received a copy of the GNU Affero General Public License
16   * along with this program.  If not, see <https://www.gnu.org/licenses/>.
17   */
18  
19  #[derive(Clone)]
20  pub struct RingBuffer<T, const N: usize> {
21      vals: [Option<T>; N],
22      head: i64,
23      tail: i64,
24  }
25  
26  impl<T, const N: usize> RingBuffer<T, N> {
27      const LEN: usize = N;
28  
29      pub fn new() -> Self {
30          Self { vals: [const { None }; N], head: -1, tail: -1 }
31      }
32  
33      pub fn push(&mut self, v: T) {
34          let len = Self::LEN as i64;
35  
36          self.head = (self.head + 1) % len;
37          if self.head == self.tail {
38              self.tail = (self.tail + 1) % len;
39          }
40  
41          if self.tail < 0 {
42              self.tail = 0;
43          }
44  
45          let _ = std::mem::replace(&mut self.vals[self.head as usize], Some(v));
46      }
47  
48      pub fn head(&self) -> Option<&T> {
49          if self.head < 0 {
50              return None
51          }
52          Some(self.vals[self.head as usize].as_ref().unwrap())
53      }
54  
55      pub fn tail(&self) -> Option<&T> {
56          if self.tail < 0 {
57              return None
58          }
59          Some(self.vals[self.tail as usize].as_ref().unwrap())
60      }
61  }