C++11-ify virtualisation in lwIP classes

Use `override` and `final` where appropriate, and eliminate unnecessary
`virtual`.

Some other C++11 simplifications.

Author: kjbracey

features/lwipstack/LWIPMemoryManager.h

@@ -19,7 +19,7 @@
 #include "EMACMemoryManager.h"
 
 
-class LWIPMemoryManager : public EMACMemoryManager {
+class LWIPMemoryManager final : public EMACMemoryManager {
 public:
 
     /**
@@ -31,7 +31,7 @@ class LWIPMemoryManager : public EMACMemoryManager {
      * @param align    Memory alignment requirement in bytes
      * @return         Allocated memory buffer, or NULL in case of error
      */
-    virtual net_stack_mem_buf_t *alloc_heap(uint32_t size, uint32_t align);
+    net_stack_mem_buf_t *alloc_heap(uint32_t size, uint32_t align) override;
 
     /**
      * Allocates memory buffer chain from a pool
@@ -44,7 +44,7 @@ class LWIPMemoryManager : public EMACMemoryManager {
      * @param  align   Memory alignment requirement for each buffer in bytes
      * @return         Allocated memory buffer chain, or NULL in case of error
      */
-    virtual net_stack_mem_buf_t *alloc_pool(uint32_t size, uint32_t align);
+    net_stack_mem_buf_t *alloc_pool(uint32_t size, uint32_t align) override;
 
     /**
      * Get memory buffer pool allocation unit
@@ -54,7 +54,7 @@ class LWIPMemoryManager : public EMACMemoryManager {
      * @param align    Memory alignment requirement in bytes
      * @return         Contiguous memory size
      */
-    virtual uint32_t get_pool_alloc_unit(uint32_t align) const;
+    uint32_t get_pool_alloc_unit(uint32_t align) const override;
 
     /**
      * Free memory buffer chain
@@ -64,7 +64,7 @@ class LWIPMemoryManager : public EMACMemoryManager {
      *
      * @param buf      Memory buffer chain to be freed.
      */
-    virtual void free(net_stack_mem_buf_t *buf);
+    void free(net_stack_mem_buf_t *buf) override;
 
     /**
      * Return total length of a memory buffer chain
@@ -74,7 +74,7 @@ class LWIPMemoryManager : public EMACMemoryManager {
      * @param buf      Memory buffer chain
      * @return         Total length in bytes
      */
-    virtual uint32_t get_total_len(const net_stack_mem_buf_t *buf) const;
+    uint32_t get_total_len(const net_stack_mem_buf_t *buf) const override;
 
     /**
      * Copy a memory buffer chain
@@ -85,7 +85,7 @@ class LWIPMemoryManager : public EMACMemoryManager {
      * @param to_buf    Memory buffer chain to copy to
      * @param from_buf  Memory buffer chain to copy from
      */
-    virtual void copy(net_stack_mem_buf_t *to_buf, const net_stack_mem_buf_t *from_buf);
+    void copy(net_stack_mem_buf_t *to_buf, const net_stack_mem_buf_t *from_buf) override;
 
     /**
      * Copy to a memory buffer chain
@@ -98,7 +98,7 @@ class LWIPMemoryManager : public EMACMemoryManager {
      * @param ptr       Pointer to data
      * @param len       Data length
      */
-    virtual void copy_to_buf(net_stack_mem_buf_t *to_buf, const void *ptr, uint32_t len);
+    void copy_to_buf(net_stack_mem_buf_t *to_buf, const void *ptr, uint32_t len) override;
 
     /**
      * Copy from a memory buffer chain
@@ -110,7 +110,7 @@ class LWIPMemoryManager : public EMACMemoryManager {
      * @param from_buf  Memory buffer chain to copy from
      * @return          Length of the data that was copied
      */
-    virtual uint32_t copy_from_buf(void *ptr, uint32_t len, const net_stack_mem_buf_t *from_buf) const;
+    uint32_t copy_from_buf(void *ptr, uint32_t len, const net_stack_mem_buf_t *from_buf) const override;
 
     /**
      * Concatenate two memory buffer chains
@@ -122,7 +122,7 @@ class LWIPMemoryManager : public EMACMemoryManager {
      * @param to_buf   Memory buffer chain to concatenate to
      * @param cat_buf  Memory buffer chain to concatenate
      */
-    virtual void cat(net_stack_mem_buf_t *to_buf, net_stack_mem_buf_t *cat_buf);
+    void cat(net_stack_mem_buf_t *to_buf, net_stack_mem_buf_t *cat_buf) override;
 
     /**
      * Returns the next buffer
@@ -132,23 +132,23 @@ class LWIPMemoryManager : public EMACMemoryManager {
      * @param buf      Memory buffer
      * @return         The next memory buffer, or NULL if last
      */
-    virtual net_stack_mem_buf_t *get_next(const net_stack_mem_buf_t *buf) const;
+    net_stack_mem_buf_t *get_next(const net_stack_mem_buf_t *buf) const override;
 
     /**
      * Return pointer to the payload of the buffer
      *
      * @param buf      Memory buffer
      * @return         Pointer to the payload
      */
-    virtual void *get_ptr(const net_stack_mem_buf_t *buf) const;
+    void *get_ptr(const net_stack_mem_buf_t *buf) const override;
 
     /**
      * Return payload size of the buffer
      *
      * @param buf      Memory buffer
      * @return         Size in bytes
      */
-    virtual uint32_t get_len(const net_stack_mem_buf_t *buf) const;
+    uint32_t get_len(const net_stack_mem_buf_t *buf) const override;
 
     /**
      * Sets the payload size of the buffer
@@ -159,7 +159,7 @@ class LWIPMemoryManager : public EMACMemoryManager {
      * @param buf      Memory buffer
      * @param len      Payload size, must be less or equal allocated size
      */
-    virtual void set_len(net_stack_mem_buf_t *buf, uint32_t len);
+    void set_len(net_stack_mem_buf_t *buf, uint32_t len) override;
 
 private: