implement Path::dirname()

src/lib/src/Path.cc

@@ -16,8 +16,26 @@ namespace jes
 
     Path Path::dirname()
     {
-        // TODO
-        return "";
+        size_t i = m_path.size() - 1;
+        while (m_path[i] == '/')
+        {
+            if (i == 0)
+                return "/";
+            i--;
+        }
+        while (m_path[i] != '/')
+        {
+            if (i == 0)
+                return ".";
+            i--;
+        }
+        while (m_path[i] == '/')
+        {
+            if (i == 0)
+                return "/";
+            i--;
+        }
+        return std::string(m_path, 0, i + 1);
     }
 
     Path Path::join(const Path & other)