Add support for optional C-array as container mapping

1 files changed, 102 insertions, 0 deletions

diff --git a/odb/c-array-traits.hxx b/odb/c-array-traits.hxx
new file mode 100644
index 0000000..1acc0d7
--- /dev/null
+++ b/odb/c-array-traits.hxx
@@ -0,0 +1,102 @@
+// file      : odb/c-array-traits.hxx
+// copyright : Copyright (c) 2009-2019 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#ifndef ODB_C_ARRAY_TRAITS_HXX
+#define ODB_C_ARRAY_TRAITS_HXX
+
+#include <odb/pre.hxx>
+
+#include <cstddef> // std::size_t
+#include <cassert>
+
+#include <odb/container-traits.hxx>
+
+namespace odb
+{
+  // Optional mapping of C arrays as containers. Note that this mapping is not
+  // enable by default. To enable, pass the following options to the ODB
+  // compiler:
+  //
+  // --odb-epilogue '#include <odb/c-array-traits.hxx>'
+  // --hxx-prologue '#include <odb/c-array-traits.hxx>'
+  //
+  // Note also that the array types have to be named, for example:
+  //
+  // class object
+  // {
+  //   // composite_type values[5]; // Won't work.
+  //
+  //   typedef composite_type composite_array[5];
+  //   composite_array values;
+  // };
+  //
+  // Finally, this mapping is disabled for the char[N] and wchar_t[N] types
+  // (they are mapped as strings by default).
+  //
+  template <typename V, std::size_t N>
+  class access::container_traits<V[N]>
+  {
+  public:
+    static const container_kind kind = ck_ordered;
+    static const bool smart = false;
+
+    typedef V container_type[N];
+
+    typedef V value_type;
+    typedef std::size_t index_type;
+
+    typedef ordered_functions<index_type, value_type> functions;
+
+  public:
+    static void
+    persist (const container_type& c, const functions& f)
+    {
+      for (index_type i (0); i < N; ++i)
+        f.insert (i, c[i]);
+    }
+
+    static void
+    load (container_type& c, bool more, const functions& f)
+    {
+      index_type i (0);
+
+      for (; more && i < N; ++i)
+      {
+        index_type dummy;
+        more = f.select (dummy, c[i]);
+      }
+
+      assert (!more && i == N);
+    }
+
+    static void
+    update (const container_type& c, const functions& f)
+    {
+      f.delete_ ();
+
+      for (index_type i (0); i < N; ++i)
+        f.insert (i, c[i]);
+    }
+
+    static void
+    erase (const functions& f)
+    {
+      f.delete_ ();
+    }
+  };
+
+  // Disable for char[N] and wchar_t[N].
+  //
+  template <std::size_t N>
+  class access::container_traits<char[N]>;
+
+#ifdef _WIN32
+  template <std::size_t N>
+  class access::container_traits<wchar_t[N]>;
+#endif
+}
+
+#include <odb/post.hxx>
+
+#endif // ODB_C_ARRAY_TRAITS_HXX