view: add validator specialisation

view.hpp

@@ -3,18 +3,17 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
- * Copyright 2015-2018 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2015-2019 Danny Robson <danny@nerdcruft.net>
  */
 
-
-#ifndef CRUFT_UTIL_VIEW_HPP
-#define CRUFT_UTIL_VIEW_HPP
+#pragma once
 
 #include "annotation.hpp"
 #include "cast.hpp"
-#include "types/traits.hpp"
+#include "debug.hpp"
 #include "maths.hpp"
 #include "platform.hpp"
+#include "types/traits.hpp"
 
 #include <cstdlib>
 #include <iosfwd>
@@ -893,9 +892,25 @@ namespace cruft {
 
         return res < 0 || (res == 0 && la < lb);
     }
-
-
 }
 
-
-#endif
+namespace cruft::debug {
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename IteratorT, typename ...ArgsT>
+    struct validator<
+        view<IteratorT>,
+        ArgsT&&...
+    > {
+        static bool
+        is_valid (view<IteratorT> data, ArgsT &&...args)
+        {
+            return std::all_of (
+                std::begin (data),
+                std::end   (data),
+                [&] (auto const &i)
+            {
+                return ::cruft::debug::is_valid (i, args...);
+            });
+        }
+    };
+};