From 7bfb763e0990aac1b0bc4ad95dcc55df53cdb6d9 Mon Sep 17 00:00:00 2001
From: Dario Nieuwenhuis <dirbaio@dirbaio.net>
Date: Thu, 29 Jul 2021 13:44:51 +0200
Subject: Rename embassy-extras to embassy-hal-common

---
 embassy-hal-common/src/ring_buffer.rs | 84 +++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 embassy-hal-common/src/ring_buffer.rs

(limited to 'embassy-hal-common/src/ring_buffer.rs')

diff --git a/embassy-hal-common/src/ring_buffer.rs b/embassy-hal-common/src/ring_buffer.rs
new file mode 100644
index 000000000..18795787f
--- /dev/null
+++ b/embassy-hal-common/src/ring_buffer.rs
@@ -0,0 +1,84 @@
+pub struct RingBuffer<'a> {
+    buf: &'a mut [u8],
+    start: usize,
+    end: usize,
+    empty: bool,
+}
+
+impl<'a> RingBuffer<'a> {
+    pub fn new(buf: &'a mut [u8]) -> Self {
+        Self {
+            buf,
+            start: 0,
+            end: 0,
+            empty: true,
+        }
+    }
+
+    pub fn push_buf(&mut self) -> &mut [u8] {
+        if self.start == self.end && !self.empty {
+            trace!("  ringbuf: push_buf empty");
+            return &mut self.buf[..0];
+        }
+
+        let n = if self.start <= self.end {
+            self.buf.len() - self.end
+        } else {
+            self.start - self.end
+        };
+
+        trace!("  ringbuf: push_buf {:?}..{:?}", self.end, self.end + n);
+        &mut self.buf[self.end..self.end + n]
+    }
+
+    pub fn push(&mut self, n: usize) {
+        trace!("  ringbuf: push {:?}", n);
+        if n == 0 {
+            return;
+        }
+
+        self.end = self.wrap(self.end + n);
+        self.empty = false;
+    }
+
+    pub fn pop_buf(&mut self) -> &mut [u8] {
+        if self.empty {
+            trace!("  ringbuf: pop_buf empty");
+            return &mut self.buf[..0];
+        }
+
+        let n = if self.end <= self.start {
+            self.buf.len() - self.start
+        } else {
+            self.end - self.start
+        };
+
+        trace!("  ringbuf: pop_buf {:?}..{:?}", self.start, self.start + n);
+        &mut self.buf[self.start..self.start + n]
+    }
+
+    pub fn pop(&mut self, n: usize) {
+        trace!("  ringbuf: pop {:?}", n);
+        if n == 0 {
+            return;
+        }
+
+        self.start = self.wrap(self.start + n);
+        self.empty = self.start == self.end;
+    }
+
+    pub fn clear(&mut self) {
+        self.start = 0;
+        self.end = 0;
+        self.empty = true;
+    }
+
+    fn wrap(&self, n: usize) -> usize {
+        assert!(n <= self.buf.len());
+        if n == self.buf.len() {
+            0
+        } else {
+            n
+        }
+    }
+}
-- 
cgit