view: add write consuming operations

view.hpp

@@ -806,6 +806,8 @@ namespace cruft {
     ///
     /// in contrast to 'extract' this will always copy the bytes out from the
     /// view, making the operation alignment safe.
+    ///
+    /// It is safe to use this on untrusted input.
     template <
         typename ValueT,
         typename WordT,
@@ -828,6 +830,54 @@ namespace cruft {
     }
 
 
+    ///////////////////////////////////////////////////////////////////////////
+    template <
+        typename ValueT,
+        typename WordT,
+        typename = std::enable_if_t<sizeof (ValueT) % sizeof (WordT) == 0>
+    >
+    view<WordT*>
+    write [[nodiscard]] (view<WordT*> const &dst, ValueT const &src)
+    {
+        static_assert (std::is_trivially_copyable_v<ValueT>);
+
+        if (unlikely (sizeof (ValueT) > dst.size () * sizeof (WordT)))
+            throw std::runtime_error ("insufficient data for extraction");
+
+        memcpy (dst.data (), &src, sizeof (ValueT));
+        return {
+            dst.begin () + sizeof (ValueT) / sizeof (WordT),
+            dst.end   (),
+        };
+    }
+
+
+    template <
+        typename ValueT,
+        typename WordT,
+        typename = std::enable_if_t<sizeof (ValueT) % sizeof (WordT) == 0>
+    >
+    view<WordT*>
+    write [[nodiscard]] (view<WordT*> const &dst, cruft::view<ValueT const*> src)
+    {
+        static_assert (std::is_trivially_copyable_v<ValueT>);
+
+        if (unlikely (src.size () * sizeof (ValueT) > dst.size () * sizeof (WordT)))
+            throw std::runtime_error ("insufficient data for extraction");
+
+        memcpy (
+            dst.data (),
+            src.data (),
+            src.size () * sizeof (ValueT)
+        );
+
+        return {
+            dst.begin () + (sizeof (ValueT) / sizeof (WordT)) * src.size (),
+            dst.end   (),
+        };
+    }
+
+
     ///////////////////////////////////////////////////////////////////////////
     /// Tests whether an iterator falls within a given view.
     template <typename IteratorT>