From 88fb6802608818b70617340b1ed826c1b8a9f1ea Mon Sep 17 00:00:00 2001
From: Constantin Michael <constantin@codesynthesis.com>
Date: Fri, 27 May 2011 17:21:38 +0200
Subject: Add traits

---
 odb/pgsql/traits.cxx |  58 ++++++++++
 odb/pgsql/traits.hxx | 291 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 349 insertions(+)
 create mode 100644 odb/pgsql/traits.cxx
 create mode 100644 odb/pgsql/traits.hxx

diff --git a/odb/pgsql/traits.cxx b/odb/pgsql/traits.cxx
new file mode 100644
index 0000000..bdffa45
--- /dev/null
+++ b/odb/pgsql/traits.cxx
@@ -0,0 +1,58 @@
+// file      : odb/pgsql/traits.cxx
+// author    : Constantin Michael <constantin@codesynthesis.com>
+// copyright : Copyright (c) 2005-2011 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#include <cstring> // std::memcpy, std::strlen
+
+#include <odb/pgsql/traits.hxx>
+
+using namespace std;
+
+namespace odb
+{
+  namespace pgsql
+  {
+    using details::buffer;
+
+    //
+    // string_value_traits
+    //
+
+    void string_value_traits::
+    set_image (buffer& b,
+               size_t& n,
+               bool& is_null,
+               const string& v)
+    {
+      is_null = false;
+      n = v.size ();
+
+      if (n > b.capacity ())
+        b.capacity (n);
+
+      if (n != 0)
+        memcpy (b.data (), v.c_str (), n);
+    }
+
+    //
+    // c_string_value_traits
+    //
+
+    void c_string_value_traits::
+    set_image (buffer& b,
+               size_t& n,
+               bool& is_null,
+               const char* v)
+    {
+      is_null = false;
+      n = strlen (v);
+
+      if (n > b.capacity ())
+        b.capacity (n);
+
+      if (n != 0)
+        memcpy (b.data (), v, n);
+    }
+  }
+}
diff --git a/odb/pgsql/traits.hxx b/odb/pgsql/traits.hxx
new file mode 100644
index 0000000..62a6df2
--- /dev/null
+++ b/odb/pgsql/traits.hxx
@@ -0,0 +1,291 @@
+// file      : odb/pgsql/traits.hxx
+// author    : Constantin Michael <constantin@codesynthesis.com>
+// copyright : Copyright (c) 2005-2011 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#ifndef ODB_PGSQL_TRAITS_HXX
+#define ODB_PGSQL_TRAITS_HXX
+
+#include <odb/pre.hxx>
+
+#include <string>
+#include <cstddef> // std::size_t
+
+#include <odb/traits.hxx>
+
+#include <odb/details/buffer.hxx>
+
+#include <odb/pgsql/version.hxx>
+#include <odb/pgsql/pgsql-types.hxx>
+
+#include <odb/pgsql/details/export.hxx>
+
+namespace odb
+{
+  namespace pgsql
+  {
+    enum database_type_id
+    {
+      id_boolean,
+      id_smallint,
+      id_integer,
+      id_bigint,
+      id_numeric,
+      id_real,
+      id_double,
+      id_serial,
+      id_bigserial,
+
+      id_string
+    };
+
+    //
+    // image_traits
+    //
+
+    template <database_type_id>
+    struct image_traits;
+
+    template <>
+    struct image_traits<id_smallint> {typedef short image_type;};
+
+    template <>
+    struct image_traits<id_integer> {typedef int image_type;};
+
+    template <>
+    struct image_traits<id_bigint> {typedef long long image_type;};
+
+    template <>
+    struct image_traits<id_numeric> {typedef details::buffer image_type;};
+
+    template <>
+    struct image_traits<id_real> {typedef float image_type;};
+
+    template <>
+    struct image_traits<id_double> {typedef double image_type;};
+
+    //
+    // value_traits
+    //
+
+    template <typename T, database_type_id>
+    struct default_value_traits;
+
+    template <typename T, database_type_id ID>
+    class value_traits: public default_value_traits<T, ID>
+    {
+    };
+
+    template <typename T, database_type_id ID>
+    struct default_value_traits
+    {
+      typedef T value_type;
+      typedef T query_type;
+      typedef typename image_traits<ID>::image_type image_type;
+
+      static void
+      set_value (T& v, const image_type& i, bool is_null)
+      {
+        if (!is_null)
+          v = T (i);
+        else
+          v = T ();
+      }
+
+      static void
+      set_image (image_type& i, bool& is_null, T v)
+      {
+        is_null = false;
+        i = image_type (v);
+      }
+    };
+
+    // std::string specialization.
+    //
+    class LIBODB_PGSQL_EXPORT string_value_traits
+    {
+    public:
+      typedef std::string value_type;
+      typedef std::string query_type;
+      typedef details::buffer image_type;
+
+      static void
+      set_value (std::string& v,
+                 const details::buffer& b,
+                 std::size_t n,
+                 bool is_null)
+      {
+        if (!is_null)
+          v.assign (b.data (), n);
+        else
+          v.erase ();
+      }
+
+      static void
+      set_image (details::buffer&,
+                 std::size_t& n,
+                 bool& is_null,
+                 const std::string&);
+    };
+
+    template <>
+    struct LIBODB_PGSQL_EXPORT default_value_traits<std::string, id_numeric>:
+      string_value_traits
+    {
+    };
+
+    template <>
+    struct LIBODB_PGSQL_EXPORT default_value_traits<std::string, id_string>:
+      string_value_traits
+    {
+    };
+
+    // const char* specialization
+    //
+    // Specialization for const char* which only supports initialization
+    // of an image from the value but not the other way around. This way
+    // we can pass such values to the queries.
+    //
+    class LIBODB_PGSQL_EXPORT c_string_value_traits
+    {
+    public:
+      typedef const char* value_type;
+      typedef const char* query_type;
+      typedef details::buffer image_type;
+
+      static void
+      set_image (details::buffer&,
+                 std::size_t& n,
+                 bool& is_null,
+                 const char*);
+    };
+
+    template <>
+    struct LIBODB_PGSQL_EXPORT default_value_traits<const char*, id_numeric>:
+      c_string_value_traits
+    {
+    };
+
+    template <>
+    struct LIBODB_PGSQL_EXPORT default_value_traits<const char*, id_string>:
+      c_string_value_traits
+    {
+    };
+
+    //
+    // type_traits
+    //
+
+    template <typename T>
+    struct default_type_traits;
+
+    template <typename T>
+    class type_traits: public default_type_traits<T>
+    {
+    };
+
+    // Integral types.
+    //
+    template <>
+    struct default_type_traits<bool>
+    {
+      static const database_type_id db_type_id = id_boolean;
+    };
+
+    template <>
+    struct default_type_traits<signed char>
+    {
+      static const database_type_id db_type_id = id_smallint;
+    };
+
+    template <>
+    struct default_type_traits<unsigned char>
+    {
+      static const database_type_id db_type_id = id_smallint;
+    };
+
+    template <>
+    struct default_type_traits<short>
+    {
+      static const database_type_id db_type_id = id_smallint;
+    };
+
+    template <>
+    struct default_type_traits<unsigned short>
+    {
+      static const database_type_id db_type_id = id_integer;
+    };
+
+    template <>
+    struct default_type_traits<int>
+    {
+      static const database_type_id db_type_id = id_integer;
+    };
+
+    template <>
+    struct default_type_traits<unsigned int>
+    {
+      static const database_type_id db_type_id = id_bigint;
+    };
+
+    template <>
+    struct default_type_traits<long>
+    {
+      static const database_type_id db_type_id = id_bigint;
+    };
+
+    template <>
+    struct default_type_traits<unsigned long>
+    {
+      static const database_type_id db_type_id = id_bigint;
+    };
+
+    template <>
+    struct default_type_traits<long long>
+    {
+      static const database_type_id db_type_id = id_bigint;
+    };
+
+    // @@ No representation for an unsigned 64 bit value.
+    // Should we force a compile time error with a message
+    // or just truncate?
+    //
+    // template <>
+    // struct default_type_traits<unsigned long long>
+    // {
+    //   static const database_type_id db_type_id = id_ulonglong;
+    // };
+
+    // Float types.
+    //
+    template <>
+    struct default_type_traits<float>
+    {
+      static const database_type_id db_type_id = id_real;
+    };
+
+    template <>
+    struct default_type_traits<double>
+    {
+      static const database_type_id db_type_id = id_double;
+    };
+
+    // String type.
+    //
+    template <>
+    struct default_type_traits<std::string>
+    {
+      static const database_type_id db_type_id = id_string;
+    };
+
+    template <>
+    struct default_type_traits<const char*>
+    {
+      static const database_type_id db_type_id = id_string;
+    };
+  }
+}
+
+#include <odb/post.hxx>
+
+#endif // ODB_PGSQL_TRAITS_HXX
-- 
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