add an EOF iterator to track the end of the file and number of lines

src/core/Buffer.cc

@@ -8,31 +8,36 @@
 
 Buffer::Buffer()
 {
-    common_initialization();
     load_empty_buffer();
+    common_initialization();
 }
 
 Buffer::Buffer(const char * filename)
 {
-    common_initialization();
     if (!load_from_file(filename))
     {
         load_empty_buffer();
     }
+    common_initialization();
 }
 
 Buffer::Buffer(const uint8_t * data, size_t data_length)
 {
-    common_initialization();
     if (!load_from_memory(data, data_length))
     {
         load_empty_buffer();
     }
+    common_initialization();
 }
 
 void Buffer::common_initialization()
 {
     m_tabstop = 4u;
+    m_eof_iterator = add_iterator();
+    while (m_eof_iterator->valid())
+    {
+        m_eof_iterator->go_forward();
+    }
 }
 
 void Buffer::load_empty_buffer()

src/core/Buffer.h

@@ -119,6 +119,7 @@ protected:
     bool m_insert_mode;
     size_t m_insert_position;
     std::list<std::shared_ptr<Iterator>> m_iterators;
+    std::shared_ptr<Iterator> m_eof_iterator;
     std::string m_filename;
 
     void common_initialization();