array: add varray wrapper

CMakeLists.txt

@@ -223,6 +223,7 @@ list (
     array/sarray.hpp
     array/parray.cpp
     array/parray.hpp
+    array/varray.hpp
     ascii.hpp
     backtrace.hpp
     bezier.cpp

array/varray.hpp

@@ -0,0 +1,75 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * 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 2019 Danny Robson <danny@nerdcruft.net>
+ */
+
+#pragma once
+
+#include "../debug.hpp"
+
+#include <array>
+#include <cstddef>
+#include <iterator>
+
+namespace cruft {
+    /// A view of a compile-time sized array.
+    ///
+    /// \tparam S the number of elements
+    /// \tparam T the data type of the elements
+    template <std::size_t S, typename T>
+    class varray {
+    public:
+        using iterator_category = std::random_access_iterator_tag;
+        using value_type = T;
+        using reference_type = T&;
+        using pointer = T*;
+        using difference_type = std::size_t;
+        using size_type = std::size_t;
+
+        //---------------------------------------------------------------------
+        varray (varray const &rhs)
+          : m_data (rhs.m_data)
+        { ; }
+
+
+        //-------------------------------------------------------------------------
+        varray (std::array<T,S> &rhs)
+          : m_data (std::data (rhs))
+        { ; }
+
+        varray (std::array<T,S> &&) = delete;
+
+        //-------------------------------------------------------------------------
+        varray (T (&_data)[S])
+          : m_data (_data)
+        { ; }
+
+        //---------------------------------------------------------------------
+        std::size_t size (void) const { return S; }
+
+        T& operator[] (std::size_t i) { CHECK_LIMIT (i, 0u, S); return m_data[i]; }
+        const T& operator[] (std::size_t i) const { CHECK_LIMIT (i, 0u, S); return m_data[i]; }
+
+        auto data (void) { return m_data; }
+        auto data (void) const { return m_data; }
+
+        auto begin (void) { return data (); }
+        auto end   (void) { return data () + size (); }
+
+        auto begin (void) const { return data (); }
+        auto end   (void) const { return data () + size (); }
+
+        auto cbegin (void) const { return data (); }
+        auto cend   (void) const { return data () + size (); }
+
+    private:
+        T *m_data;
+    };
+
+
+    template <typename T, std::size_t S>
+    varray (T(&)[S]) -> varray<S,T>;
+}