[file_handler] additional functions for count checking

nixview/file_handler.py

@@ -110,16 +110,27 @@ class FileHandler(metaclass=Singleton):
     @property
     def filename(self):
         return self._filename
-
+    
+    def valid_count(self, shape, offset, count):
+        valid_count = np.empty(len(shape), dtype=int)
+        for i, (o, c) in enumerate(zip(offset, count)):
+            if o + c > shape[i]:
+                valid_count[i] = shape[i] - o
+        return valid_count
+    
+    def count_is_valid(self, shape, offset, count):
+        res = True
+        for s, o, c in zip(shape, offset, count):
+            res = res and o + c <= s
+        return res
+    
     def request_data(self, entity_descriptor, offset=None, count=None):
         entity = self._entity_buffer.get(entity_descriptor.id)
         if entity is None:
-            print("need to do something else")
-        for i, (o, c) in enumerate(zip(offset, count)):
-            if o + c > entity.shape[i]:
-                count[i] = entity.shape[i] - o
+            raise ValueError("Entity is invalid: %s" % entity_descriptor)
+        if not self.count_is_valid(entity.shape, offset, count):
+            count = self.valid_count(entity.shape, offset, count)
         seg = tuple([slice(o, o + c) for o, c in zip(offset, count)])
-        print(seg)
         return entity[seg]
 
     def request_section_descriptor(self, id):