139 lines
2.8 KiB
Rust
139 lines
2.8 KiB
Rust
use core::ops::Range;
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pub struct RingBuffer<const N: usize> {
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start: usize,
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end: usize,
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empty: bool,
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}
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impl<const N: usize> RingBuffer<N> {
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pub const fn new() -> Self {
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Self {
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start: 0,
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end: 0,
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empty: true,
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}
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}
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pub fn push_buf(&mut self) -> Range<usize> {
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if self.start == self.end && !self.empty {
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trace!(" ringbuf: push_buf empty");
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return 0..0;
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}
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let n = if self.start <= self.end {
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N - self.end
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} else {
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self.start - self.end
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};
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trace!(" ringbuf: push_buf {:?}..{:?}", self.end, self.end + n);
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self.end..self.end + n
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}
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pub fn push(&mut self, n: usize) {
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trace!(" ringbuf: push {:?}", n);
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if n == 0 {
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return;
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}
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self.end = self.wrap(self.end + n);
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self.empty = false;
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}
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pub fn pop_buf(&mut self) -> Range<usize> {
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if self.empty {
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trace!(" ringbuf: pop_buf empty");
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return 0..0;
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}
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let n = if self.end <= self.start {
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N - self.start
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} else {
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self.end - self.start
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};
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trace!(" ringbuf: pop_buf {:?}..{:?}", self.start, self.start + n);
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self.start..self.start + n
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}
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pub fn pop(&mut self, n: usize) {
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trace!(" ringbuf: pop {:?}", n);
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if n == 0 {
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return;
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}
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self.start = self.wrap(self.start + n);
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self.empty = self.start == self.end;
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}
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pub fn is_full(&self) -> bool {
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self.start == self.end && !self.empty
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}
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pub fn is_empty(&self) -> bool {
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self.empty
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}
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#[allow(unused)]
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pub fn len(&self) -> usize {
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if self.empty {
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0
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} else if self.start < self.end {
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self.end - self.start
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} else {
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N + self.end - self.start
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}
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}
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pub fn clear(&mut self) {
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self.start = 0;
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self.end = 0;
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self.empty = true;
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}
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fn wrap(&self, n: usize) -> usize {
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assert!(n <= N);
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if n == N {
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0
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} else {
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n
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn push_pop() {
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let mut rb: RingBuffer<4> = RingBuffer::new();
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let buf = rb.push_buf();
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assert_eq!(0..4, buf);
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rb.push(4);
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let buf = rb.pop_buf();
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assert_eq!(0..4, buf);
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rb.pop(1);
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let buf = rb.pop_buf();
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assert_eq!(1..4, buf);
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rb.pop(1);
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let buf = rb.pop_buf();
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assert_eq!(2..4, buf);
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rb.pop(1);
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let buf = rb.pop_buf();
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assert_eq!(3..4, buf);
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rb.pop(1);
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let buf = rb.pop_buf();
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assert_eq!(0..0, buf);
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let buf = rb.push_buf();
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assert_eq!(0..4, buf);
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}
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}
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