1 files changed, 157 insertions, 0 deletions
diff --git a/src/rxqueue.rs b/src/rxqueue.rs
new file mode 100644
index 0000000..4b76727
--- /dev/null
+++ b/src/rxqueue.rs
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: Apache-2.0 or BSD-3-Clause
+
+use crate::rxops::RxOps;
+
+#[derive(Debug, Eq, PartialEq)]
+pub(crate) struct RxQueue {
+    /// Bitmap of rx operations.
+    queue: u8,
+}
+
+impl RxQueue {
+    /// New instance of RxQueue.
+    pub fn new() -> Self {
+        RxQueue { queue: 0_u8 }
+    }
+
+    /// Enqueue a new rx operation into the queue.
+    pub fn enqueue(&mut self, op: RxOps) {
+        self.queue |= op.bitmask();
+    }
+
+    /// Dequeue an rx operation from the queue.
+    pub fn dequeue(&mut self) -> Option<RxOps> {
+        match self.peek() {
+            Some(req) => {
+                self.queue &= !req.bitmask();
+                Some(req)
+            }
+            None => None,
+        }
+    }
+
+    /// Peek into the queue to check if it contains an rx operation.
+    pub fn peek(&self) -> Option<RxOps> {
+        if self.contains(RxOps::Request.bitmask()) {
+            return Some(RxOps::Request);
+        }
+        if self.contains(RxOps::Rw.bitmask()) {
+            return Some(RxOps::Rw);
+        }
+        if self.contains(RxOps::Response.bitmask()) {
+            return Some(RxOps::Response);
+        }
+        if self.contains(RxOps::CreditUpdate.bitmask()) {
+            return Some(RxOps::CreditUpdate);
+        }
+        if self.contains(RxOps::Reset.bitmask()) {
+            Some(RxOps::Reset)
+        } else {
+            None
+        }
+    }
+
+    /// Check if the queue contains a particular rx operation.
+    pub fn contains(&self, op: u8) -> bool {
+        (self.queue & op) != 0
+    }
+
+    /// Check if there are any pending rx operations in the queue.
+    pub fn pending_rx(&self) -> bool {
+        self.queue != 0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_contains() {
+        let mut rxqueue = RxQueue::new();
+        rxqueue.queue = 31;
+
+        assert!(rxqueue.contains(RxOps::Request.bitmask()));
+        assert!(rxqueue.contains(RxOps::Rw.bitmask()));
+        assert!(rxqueue.contains(RxOps::Response.bitmask()));
+        assert!(rxqueue.contains(RxOps::CreditUpdate.bitmask()));
+        assert!(rxqueue.contains(RxOps::Reset.bitmask()));
+
+        rxqueue.queue = 0;
+        assert!(!rxqueue.contains(RxOps::Request.bitmask()));
+        assert!(!rxqueue.contains(RxOps::Rw.bitmask()));
+        assert!(!rxqueue.contains(RxOps::Response.bitmask()));
+        assert!(!rxqueue.contains(RxOps::CreditUpdate.bitmask()));
+        assert!(!rxqueue.contains(RxOps::Reset.bitmask()));
+    }
+
+    #[test]
+    fn test_enqueue() {
+        let mut rxqueue = RxQueue::new();
+
+        rxqueue.enqueue(RxOps::Request);
+        assert!(rxqueue.contains(RxOps::Request.bitmask()));
+
+        rxqueue.enqueue(RxOps::Rw);
+        assert!(rxqueue.contains(RxOps::Rw.bitmask()));
+
+        rxqueue.enqueue(RxOps::Response);
+        assert!(rxqueue.contains(RxOps::Response.bitmask()));
+
+        rxqueue.enqueue(RxOps::CreditUpdate);
+        assert!(rxqueue.contains(RxOps::CreditUpdate.bitmask()));
+
+        rxqueue.enqueue(RxOps::Reset);
+        assert!(rxqueue.contains(RxOps::Reset.bitmask()));
+    }
+
+    #[test]
+    fn test_peek() {
+        let mut rxqueue = RxQueue::new();
+
+        rxqueue.queue = 31;
+        assert_eq!(rxqueue.peek(), Some(RxOps::Request));
+
+        rxqueue.queue = 30;
+        assert_eq!(rxqueue.peek(), Some(RxOps::Rw));
+
+        rxqueue.queue = 28;
+        assert_eq!(rxqueue.peek(), Some(RxOps::Response));
+
+        rxqueue.queue = 24;
+        assert_eq!(rxqueue.peek(), Some(RxOps::CreditUpdate));
+
+        rxqueue.queue = 16;
+        assert_eq!(rxqueue.peek(), Some(RxOps::Reset));
+    }
+
+    #[test]
+    fn test_dequeue() {
+        let mut rxqueue = RxQueue::new();
+        rxqueue.queue = 31;
+
+        assert_eq!(rxqueue.dequeue(), Some(RxOps::Request));
+        assert!(!rxqueue.contains(RxOps::Request.bitmask()));
+
+        assert_eq!(rxqueue.dequeue(), Some(RxOps::Rw));
+        assert!(!rxqueue.contains(RxOps::Rw.bitmask()));
+
+        assert_eq!(rxqueue.dequeue(), Some(RxOps::Response));
+        assert!(!rxqueue.contains(RxOps::Response.bitmask()));
+
+        assert_eq!(rxqueue.dequeue(), Some(RxOps::CreditUpdate));
+        assert!(!rxqueue.contains(RxOps::CreditUpdate.bitmask()));
+
+        assert_eq!(rxqueue.dequeue(), Some(RxOps::Reset));
+        assert!(!rxqueue.contains(RxOps::Reset.bitmask()));
+    }
+
+    #[test]
+    fn test_pending_rx() {
+        let mut rxqueue = RxQueue::new();
+        assert!(!rxqueue.pending_rx());
+
+        rxqueue.queue = 1;
+        assert!(rxqueue.pending_rx());
+    }
+}