implement xQueueOverwrite

Author: mattheweshleman

cpputest-for-freertos-lib/src/cpputest_for_freertos_queue.cpp

@@ -108,8 +108,11 @@ extern "C" BaseType_t xQueueGenericSend(QueueHandle_t queue,
 {
     (void)ticks;
     configASSERT(queue != nullptr);
+    configASSERT(!((itemToQueue == nullptr) && (queue->itemSize != 0U)));
+    configASSERT(!((copyPosition == queueOVERWRITE) && (queue->queueLength != 1)));
 
-    if (queue->queue.size() >= queue->queueLength)
+    if ((copyPosition != queueOVERWRITE) &&
+        (queue->queue.size() >= queue->queueLength))
     {
         return errQUEUE_FULL;
     }
@@ -126,6 +129,11 @@ extern "C" BaseType_t xQueueGenericSend(QueueHandle_t queue,
     {
         queue->queue.push_front(msg);
     }
+    else if (copyPosition == queueOVERWRITE)
+    {
+        queue->queue.pop_front();
+        queue->queue.push_front(msg);
+    }
     else
     {
         configASSERT(true == false);

cpputest-for-freertos-lib/tests/cpputest_for_freertos_queue_tests.cpp

@@ -174,3 +174,23 @@ TEST(QueueTests, can_create_a_static_queue)
     mQueueUnderTest = xQueueCreateStatic(2, sizeof(TestEventT), queueStorageArea, &staticQueue);
     CHECK_TRUE(mQueueUnderTest != nullptr);
 }
+
+TEST(QueueTests, can_use_queue_overwrite)
+{
+    const TestEventT firstEvent = { 23, 43 };
+    const TestEventT overwriteEvent = { 123, 143 };
+
+    CreateUnderTest(1, sizeof(TestEventT));
+
+    auto rtn = xQueueSendToBack(mQueueUnderTest, &firstEvent, portMAX_DELAY);
+    CHECK_EQUAL(pdTRUE, rtn);
+
+    rtn = xQueueOverwrite(mQueueUnderTest, &overwriteEvent);
+    CHECK_EQUAL(pdPASS, rtn);
+
+    TestEventT retrieved;
+    rtn = xQueueReceive(mQueueUnderTest, &retrieved, portMAX_DELAY);
+    CHECK_EQUAL(pdTRUE, rtn);
+    CHECK_EQUAL(overwriteEvent.valueA, retrieved.valueA);
+    CHECK_EQUAL(overwriteEvent.valueB, retrieved.valueB);
+}