Implemented FilePath::isAbsolute().

git-svn-id: https://svn.microneil.com/svn/CodeDweller/branches/adeniz_1@88 d34b734f-a00e-4b39-a726-e4eeb87269ab

filesystem.cpp

   char const FilePath::DirectorySeparator = '/';
 #endif
 
+  bool FilePath::isAbsolute(std::string const &path) {
+
+#ifdef _WIN32
+    return PathIsRelative(path.c_str());
+#else
+    if (path.empty()) {
+      return false;
+    }
+    return ('/' == path[0]);
+#endif
+
+  }
+
   std::string FilePath::join(std::initializer_list<std::string> components) {
 
     std::string path;
       if (!path.empty() &&
 	  path.back() != FilePath::DirectorySeparator) {
 	path += FilePath::DirectorySeparator;
+
+        if (isAbsolute(component)) {
+          throw std::invalid_argument("Attempted to use absolute path \"" +
+                                      component + "\" where a relative path "
+                                      "is required.");
+        }
+
       }
 
       path += component;

filesystem.hpp

     /// Directory separator character.
     static char const DirectorySeparator;
 
+
+    /** Check whether a path is absolute.
+
+	This method whether the specified path is absolute or not.
+
+	@param[in] path is the path to check.
+
+	@returns true if the path is an absolute path, false
+	otherwise.
+
+    */
+    static bool isAbsolute(std::string const &path);
+
     /** Join path components.
 
 	This method joins a veriable number of std::string inputs to