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// 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 <cstddef> // std::size_t
#include <algorithm> // std::reverse
namespace odb
{
namespace pgsql
{
namespace details
{
template <typename T, std::size_t 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;
char tmp (u.c[0]);
u.c[0] = u.c[1];
u.c[1] = tmp;
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;
char tmp (u.c[0]);
u.c[0] = u.c[3];
u.c[3] = tmp;
tmp = u.c[1];
u.c[1] = u.c[2];
u.c[2] = tmp;
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;
char tmp (u.c[0]);
u.c[0] = u.c[7];
u.c[7] = tmp;
tmp = u.c[1];
u.c[1] = u.c[6];
u.c[6] = tmp;
tmp = u.c[2];
u.c[2] = u.c[5];
u.c[5] = tmp;
tmp = u.c[3];
u.c[3] = u.c[4];
u.c[4] = tmp;
return u.t;
}
};
class endian_traits
{
public:
enum endian
{
big,
little
};
public:
static const endian host_endian;
public:
template <typename T>
static T
hton (T x)
{
return host_endian == big ? x : swap_endian<T>::swap (x);
}
template <typename T>
static T
ntoh (T x)
{
return host_endian == big ? x : swap_endian<T>::swap (x);
}
};
}
}
}
#endif // ODB_PGSQL_ENDIAN_TRAITS_HXX
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