view: add extract_array

view.hpp

@@ -770,6 +770,37 @@ namespace cruft {
     }
 
 
+    ///------------------------------------------------------------------------
+    /// Returns a view of the specified type cast from the front of a
+    /// byte-view.
+    ///
+    /// There may be runtime checks for alignment under debug builds.
+    ///
+    /// It is safe to use this on untrusted input. However absolutely no
+    /// validation is performed on the result data.
+    template <
+        typename ValueT,
+        typename WordT,
+        typename = std::enable_if_t<sizeof (ValueT) % sizeof(WordT) == 0>
+    >
+    cruft::view<ValueT*>
+    extract_array (view<WordT*> &src, std::size_t count)
+    {
+        static_assert (
+            std::is_const_v<ValueT> == std::is_const_v<WordT>,
+            "src and dst types must have matching constness"
+        );
+
+        auto const src_size = sizeof (ValueT) / sizeof (WordT) * count;
+        if (unlikely (src.size () < src_size))
+            throw std::runtime_error ("Insufficient data for extraction");
+
+        auto res = src.template cast<ValueT*> ().redim (count);
+        src = src.consume (src_size);
+        return res;
+    }
+
+
     ///////////////////////////////////////////////////////////////////////////
     /// extracts an object of a specified type from the front of a byte-view.
     ///