From dc5ab85e286447c91216e2f6dc5c60d8210fe2b9 Mon Sep 17 00:00:00 2001
From: jwellbelove <github@wellbelove.co.uk>
Date: Mon, 27 Oct 2014 11:30:10 +0000
Subject: [PATCH] Added back() & #error for base class

---
 iqueue.h     | 49 ++++++++++++++++++++++++++++++++++++++++++++-----
 queue.h      |  2 +-
 queue_base.h | 24 +++++++++++++-----------
 3 files changed, 58 insertions(+), 17 deletions(-)

diff --git a/iqueue.h b/iqueue.h
index a7f1948b..da769c1d 100644
--- a/iqueue.h
+++ b/iqueue.h
@@ -28,6 +28,7 @@ SOFTWARE.
 
 #ifndef __etl_iqueue__
 #define __etl_iqueue__
+#define __etl_in_iqueue_h__
 
 #include <cstddef>
 
@@ -51,7 +52,7 @@ namespace etl
   {
   public:
 
-    typedef queue_base::size_type size_type;       ///< The type used for determining the size of queue.
+    typedef queue_base::size_type size_type;       ///< The type used for determining the size of the queue.
     typedef T                     value_type;      ///< The type stored in the queue.
     typedef T&                    reference;       ///< A reference to the type used in the queue.
     typedef const T&              const_reference; ///< A const reference to the type used in the queue.
@@ -68,9 +69,9 @@ namespace etl
     {
       if (!full())
       {
-        buffer[in++] = item;
+        buffer[in] = item;
         in = (in == (MAX_SIZE - 1)) ? 0 : ++in;
-        ++size;
+        ++current_size;
       }
 #ifdef ETL_USE_EXCEPTIONS
       else
@@ -95,7 +96,7 @@ namespace etl
       if (!full())
       {
         in = (in == (MAX_SIZE - 1)) ? 0 : ++in;
-        ++size;
+        ++current_size;
       }
 #ifdef ETL_USE_EXCEPTIONS
       else
@@ -143,12 +144,48 @@ namespace etl
       return buffer[out];
     }
 
+    //*************************************************************************
+    /// Gets a reference to the item at the back of the queue.<br>
+    /// If ETL_USE_EXCEPTIONS is defined, throws an etl::queue_empty_exception if the queue is empty.<br>
+    /// If ETL_USE_EXCEPTIONS is not defined and the queue is empty, the return value is undefined.
+    /// \return A reference to the item at the back of the queue.
+    //*************************************************************************
+    reference back()
+    {
+#ifdef ETL_USE_EXCEPTIONS
+      if (empty())
+      {
+        throw queue_empty_exception();
+      }
+#endif
+
+      return buffer[in == 0 ? MAX_SIZE - 1 : in - 1];
+    }
+
+    //*************************************************************************
+    /// Gets a const reference to the item at the back of the queue.<br>
+    /// If ETL_USE_EXCEPTIONS is defined, throws an etl::queue_empty_exception if the queue is empty.<br>
+    /// If ETL_USE_EXCEPTIONS is not defined and the queue is empty, the return value is undefined.
+    /// \return A const reference to the item at the back of the queue.
+    //*************************************************************************
+    const_reference back() const
+    {
+#ifdef ETL_USE_EXCEPTIONS
+      if (empty())
+      {
+        throw queue_empty_exception();
+      }
+#endif
+
+      return buffer[in == 0 ? MAX_SIZE - 1 : in - 1];
+    }
+
   protected:
 
     //*************************************************************************
     /// The constructor that is called from derived classes.
     //*************************************************************************
-    queue(T* buffer, size_type max_size)
+    iqueue(T* buffer, size_type max_size)
       : queue_base(max_size),
         buffer(buffer)
     {
@@ -160,3 +197,5 @@ namespace etl
   };
 }
 
+#undef __etl_in_iqueue_h__
+#endif
diff --git a/queue.h b/queue.h
index d26744a4..e5525d4e 100644
--- a/queue.h
+++ b/queue.h
@@ -31,7 +31,7 @@ SOFTWARE.
 
 #include <cstddef>
 
-#include "IQueue.h"
+#include "iqueue.h"
 
 //*****************************************************************************
 ///\defgroup queue queue
diff --git a/queue_base.h b/queue_base.h
index 69835263..4218b5e7 100644
--- a/queue_base.h
+++ b/queue_base.h
@@ -26,6 +26,10 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 ******************************************************************************/
 
+#ifndef __etl_in_iqueue_h__
+#error This header is a private element of etl::queue & etl::iqueue
+#endif
+
 #ifndef __etl_queue_base__
 #define __etl_queue_base__
 
@@ -33,9 +37,6 @@ SOFTWARE.
 
 #include "exception.h"
 
-///\defgroup queue Queue
-///\ingroup containers
-
 namespace etl
 {
 #ifdef ETL_USE_EXCEPTIONS
@@ -98,7 +99,7 @@ namespace etl
     //*************************************************************************
     size_type size() const
     {
-      return size;
+      return current_size;
     }
 
     //*************************************************************************
@@ -122,9 +123,9 @@ namespace etl
     //*************************************************************************
     void clear()
     {
-      in   = 0;
-      out  = 0;
-      size = 0;
+      in  = 0;
+      out = 0;
+      current_size = 0;
     }
 
     //*************************************************************************
@@ -133,7 +134,7 @@ namespace etl
     //*************************************************************************
     bool empty() const
     {
-      return size == 0;
+      return current_size == 0;
     }
 
     //*************************************************************************
@@ -142,7 +143,7 @@ namespace etl
     //*************************************************************************
     bool full() const
     {
-      return size == MAX_SIZE;
+      return current_size == MAX_SIZE;
     }
 
     //*************************************************************************
@@ -154,7 +155,7 @@ namespace etl
       if (!empty())
       {
         out = (out == (MAX_SIZE - 1)) ? 0 : ++out;
-        --size;
+        --current_size;
       }
     }
 
@@ -171,8 +172,9 @@ namespace etl
 
     size_type in;             ///< Where to input new data.
     size_type out;            ///< Where to get the oldest data.
-    size_type size;           ///< The number of items in the queue.
+    size_type current_size;   ///< The number of items in the queue.
     const size_type MAX_SIZE; ///< The maximum number of items in the queue.
   };
 }
 
+#endif