From 8e4739f307da00d07b861866931e65c1f8d8332d Mon Sep 17 00:00:00 2001
From: Martino Facchin <m.facchin@arduino.cc>
Date: Mon, 21 Sep 2020 12:41:15 +0200
Subject: [PATCH 1/4] Properly handle the queue (keep history)

---
 Arduino_Threads.h | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/Arduino_Threads.h b/Arduino_Threads.h
index 9c2f230..69dc7c1 100644
--- a/Arduino_Threads.h
+++ b/Arduino_Threads.h
@@ -3,18 +3,20 @@ class Shared // template definition
 {
   public:
     Shared() {
-      queue = new rtos::Queue<Shared<T>, 16>;
+      queue = new rtos::Queue<T, 16>;
     }
     operator T() const {
       osEvent evt = queue->get();
       if (evt.status == osEventMessage) {
-        Shared<T> *x = (Shared<T>*)evt.value.p;
-        return x->val;
+        T x = *((T*)evt.value.p);
+        delete (T*)evt.value.p;
+        return x;
       }
     }
     T& operator= (const T& other) {
       val = other;
-      queue->put(this);
+      T* obj = new T(val);
+      queue->put(obj);
     }
     T& peek() {
       return val;
@@ -24,7 +26,7 @@ class Shared // template definition
     }
   private:
     T val;
-    rtos::Queue<Shared<T>, 16> *queue;
+    rtos::Queue<T, 16>* queue;
 };
 
 #define CONCAT2(x,y) x##y

From f5235ce2127383329ebf428268addcbee575c026 Mon Sep 17 00:00:00 2001
From: Martino Facchin <m.facchin@arduino.cc>
Date: Mon, 21 Sep 2020 13:11:29 +0200
Subject: [PATCH 2/4] Demonstrate queue proper functionality

---
 examples/Enqueue_test/Enqueue.inot      | 13 +++++++++++++
 examples/Enqueue_test/Enqueue_test.ino  | 15 +++++++++++++++
 examples/Enqueue_test/SharedVariables.h |  1 +
 3 files changed, 29 insertions(+)
 create mode 100644 examples/Enqueue_test/Enqueue.inot
 create mode 100644 examples/Enqueue_test/Enqueue_test.ino
 create mode 100644 examples/Enqueue_test/SharedVariables.h

diff --git a/examples/Enqueue_test/Enqueue.inot b/examples/Enqueue_test/Enqueue.inot
new file mode 100644
index 0000000..f7cfaf4
--- /dev/null
+++ b/examples/Enqueue_test/Enqueue.inot
@@ -0,0 +1,13 @@
+void setup() {
+  // put your setup code here, to run once:
+
+}
+
+int i = 0;
+
+void loop() {
+  // Continuously pump counter
+  delay(100);
+  i++;
+  counter = i;
+}
diff --git a/examples/Enqueue_test/Enqueue_test.ino b/examples/Enqueue_test/Enqueue_test.ino
new file mode 100644
index 0000000..c0f3b1d
--- /dev/null
+++ b/examples/Enqueue_test/Enqueue_test.ino
@@ -0,0 +1,15 @@
+void setup() {
+  // put your setup code here, to run once:
+  Serial.begin(115200);
+  while (!Serial) {}
+  Enqueue.start();
+  Serial.println("start");
+}
+
+void loop() {
+  // put your main code here, to run repeatedly:
+  delay(1000);
+  for (int i = 0; i < 10; i++) {
+    Serial.println(counter);
+  }
+}
diff --git a/examples/Enqueue_test/SharedVariables.h b/examples/Enqueue_test/SharedVariables.h
new file mode 100644
index 0000000..51ea60e
--- /dev/null
+++ b/examples/Enqueue_test/SharedVariables.h
@@ -0,0 +1 @@
+Shared<int> counter;

From 8696075ffa2711d7bc13e42992452f99444481b5 Mon Sep 17 00:00:00 2001
From: Martino Facchin <m.facchin@arduino.cc>
Date: Mon, 21 Sep 2020 13:14:03 +0200
Subject: [PATCH 3/4] PROPOSAL: discard oldest value if the queue is full

Also fixes @aentinger comment about return types
---
 Arduino_Threads.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Arduino_Threads.h b/Arduino_Threads.h
index 69dc7c1..304d9c9 100644
--- a/Arduino_Threads.h
+++ b/Arduino_Threads.h
@@ -14,9 +14,14 @@ class Shared // template definition
       }
     }
     T& operator= (const T& other) {
+      if (queue->full()) {
+        // invokes operator T()
+        T discard = *this;
+      }
       val = other;
       T* obj = new T(val);
       queue->put(obj);
+      return (*obj);
     }
     T& peek() {
       return val;

From 5bd66e7316431f62d4484e3ba4c249c967b78278 Mon Sep 17 00:00:00 2001
From: Martino Facchin <m.facchin@arduino.cc>
Date: Mon, 21 Sep 2020 17:31:15 +0200
Subject: [PATCH 4/4] Remove dynamic memory allocation

---
 Arduino_Threads.h | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/Arduino_Threads.h b/Arduino_Threads.h
index 304d9c9..38c8634 100644
--- a/Arduino_Threads.h
+++ b/Arduino_Threads.h
@@ -3,24 +3,24 @@ class Shared // template definition
 {
   public:
     Shared() {
-      queue = new rtos::Queue<T, 16>;
     }
-    operator T() const {
-      osEvent evt = queue->get();
+    operator T() {
+      osEvent evt = queue.get();
       if (evt.status == osEventMessage) {
         T x = *((T*)evt.value.p);
         delete (T*)evt.value.p;
         return x;
       }
+      return val;
     }
     T& operator= (const T& other) {
-      if (queue->full()) {
-        // invokes operator T()
+      if (queue.full()) {
+        // invokes operator T() to discard oldest element and free its memory
         T discard = *this;
       }
       val = other;
       T* obj = new T(val);
-      queue->put(obj);
+      queue.put(obj);
       return (*obj);
     }
     T& peek() {
@@ -31,7 +31,7 @@ class Shared // template definition
     }
   private:
     T val;
-    rtos::Queue<T, 16>* queue;
+    rtos::Queue<T, 16> queue;
 };
 
 #define CONCAT2(x,y) x##y