iterator: add 'iota' pseudo-container

iterator.hpp

@@ -220,6 +220,44 @@ namespace cruft {
     }
 
 
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename ValueT = std::size_t>
+    class iota {
+    public:
+        using value_type = ValueT;
+
+        iota (ValueT _total)
+          : m_total (_total)
+        { ; }
+
+        struct iterator {
+            iterator (ValueT _value)
+              : m_value (_value)
+            { ; }
+
+            ValueT const* operator-> () const noexcept { return &m_value; }
+            ValueT const& operator*  () const noexcept { return  m_value; }
+
+            iterator& operator++ () noexcept { ++m_value; return *this; }
+
+            bool operator!= (iterator const &rhs) const noexcept { return m_value != rhs.m_value; }
+
+            ValueT m_value;
+        };
+
+        iterator begin (void) const { return iterator(      0); }
+        iterator end   (void) const { return iterator(m_total); }
+        ValueT   size  (void) const { return m_total; }
+
+    private:
+        ValueT m_total;
+    };
+
+
+    template <typename ValueT>
+    iota (ValueT) -> iota<ValueT>;
+
+
     ///////////////////////////////////////////////////////////////////////////
     template <typename ContainerT>
     class indices {