Add host endian detection and endian conversion algorithms

3 files changed, 139 insertions, 0 deletions

diff --git a/odb/pgsql/endian-traits.cxx b/odb/pgsql/endian-traits.cxx
new file mode 100644
index 0000000..6730912
--- /dev/null
+++ b/odb/pgsql/endian-traits.cxx
@@ -0,0 +1,29 @@
+// file      : odb/pgsql/endian-traits.cxx
+// author    : Constantin Michael <constantin@codesynthesis.com>
+// copyright : Copyright (c) 2009-2011 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#include <odb/pgsql/endian-traits.hxx>
+
+namespace odb
+{
+  namespace pgsql
+  {
+    namespace
+    {
+      endian_traits::endian
+      infer_host_endian ()
+      {
+        short s (1);
+        char* c (reinterpret_cast<char*> (&s));
+
+        return *c == 0 ?
+          endian_traits::big_endian :
+          endian_traits::little_endian;
+      }
+    }
+
+    const endian_traits::endian endian_traits::host_endian (
+      infer_host_endian ());
+  }
+}
diff --git a/odb/pgsql/endian-traits.hxx b/odb/pgsql/endian-traits.hxx
new file mode 100644
index 0000000..07dc023
--- /dev/null
+++ b/odb/pgsql/endian-traits.hxx
@@ -0,0 +1,109 @@
+// file      : odb/pgsql/endian-traits.hxx
+// author    : Constantin Michael <constantin@codesynthesis.com>
+// copyright : Copyright (c) 2009-2011 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#ifndef ODB_PGSQL_ENDIAN_TRAITS_HXX
+#define ODB_PGSQL_ENDIAN_TRAITS_HXX
+
+#include <algorithm> // std::reverse
+
+namespace odb
+{
+  namespace pgsql
+  {
+    template <typename T, int S = sizeof (T)>
+    struct swap_endian;
+
+    template <typename T>
+    struct swap_endian<T, 2>
+    {
+      static T
+      swap (T x)
+      {
+        union u2
+        {
+          T t;
+          char c[2];
+        };
+
+        u2 u;
+        u.t = x;
+        std::reverse (u.c, u.c + 2);
+
+        return u.t;
+      }
+    };
+
+    template <typename T>
+    struct swap_endian<T, 4>
+    {
+      static T
+      swap (T x)
+      {
+        union u4
+        {
+          T t;
+          char c[4];
+        };
+
+        u4 u;
+        u.t = x;
+        std::reverse (u.c, u.c + 4);
+
+        return u.t;
+      }
+    };
+
+    template <typename T>
+    struct swap_endian<T, 8>
+    {
+      static T
+      swap (T x)
+      {
+        union u8
+        {
+          T t;
+          char c[8];
+        };
+
+        u8 u;
+        u.t = x;
+        std::reverse (u.c, u.c + 8);
+
+        return u.t;
+      }
+    };
+
+    class endian_traits
+    {
+    public:
+      enum endian
+      {
+        big_endian,
+        little_endian
+      };
+
+    public:
+      static const endian host_endian;
+
+    public:
+
+      template <typename T>
+      static T
+      hton (T x)
+      {
+        return host_endian == big_endian ? x : swap_endian<T>::swap (x);
+      }
+
+      template <typename T>
+      static T
+      ntoh (T x)
+      {
+        return host_endian == big_endian ? x : swap_endian<T>::swap (x);
+      }
+    };
+  }
+}
+
+#endif // ODB_PGSQL_ENDIAN_TRAITS_HXX
diff --git a/odb/pgsql/makefile b/odb/pgsql/makefile
index 164ebac..e448f6e 100644
--- a/odb/pgsql/makefile
+++ b/odb/pgsql/makefile
@@ -10,6 +10,7 @@ cxx :=                  \
 connection.cxx		\
 connection-factory.cxx	\
 database.cxx		\
+endian-traits.cxx	\
 error.cxx		\
 exceptions.cxx		\
 statement.cxx		\