Fixed file load bug related to dealing with relative paths correctly. The bug

prevented the load_image_dataset() routine from working on Windows systems in some
cases.

dlib/data_io/load_image_dataset.h

@@ -38,6 +38,10 @@ namespace dlib
 
         std::vector<std::vector<rectangle> > ignored_rects;
 
+        using namespace dlib::image_dataset_metadata;
+        dataset data;
+        load_image_dataset_metadata(data, filename);
+
         // Set the current directory to be the one that contains the
         // metadata file. We do this because the file might contain
         // file paths which are relative to this folder.
@@ -45,10 +49,7 @@ namespace dlib
         set_current_dir(parent_dir);
 
 
-        using namespace dlib::image_dataset_metadata;
 
-        dataset data;
-        load_image_dataset_metadata(data, filename);
 
         image_type img;
         std::vector<rectangle> rects, ignored;
@@ -113,6 +114,10 @@ namespace dlib
         object_locations.clear();
         const std::string old_working_dir = get_current_dir();
 
+        using namespace dlib::image_dataset_metadata;
+        dataset data;
+        load_image_dataset_metadata(data, filename);
+
         // Set the current directory to be the one that contains the
         // metadata file. We do this because the file might contain
         // file paths which are relative to this folder.
@@ -120,10 +125,6 @@ namespace dlib
         set_current_dir(parent_dir);
 
 
-        using namespace dlib::image_dataset_metadata;
-
-        dataset data;
-        load_image_dataset_metadata(data, filename);
         std::set<std::string> all_parts;
 
         // find out what parts are being used in the dataset.  Store results in all_parts.