/* Copyright 2003-2005 Joaquín M López Muñoz.
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE_1_0.txt or copy at
 * http://www.boost.org/LICENSE_1_0.txt)
 *
 * See http://www.boost.org/libs/multi_index for library home page.
 */

#ifndef BOOST_MULTI_INDEX_DETAIL_UINTPTR_TYPE_HPP
#define BOOST_MULTI_INDEX_DETAIL_UINTPTR_TYPE_HPP

#if defined(_MSC_VER)&&(_MSC_VER>=1200)
#pragma once
#endif

#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
#include <boost/mpl/bool.hpp>

namespace boost{

namespace multi_index{

namespace detail{

/* has_uintptr_type is an MPL integral constant determining whether
 * there exists an unsigned integral type with the same size as
 * void *.
 * uintptr_type is such a type if has_uintptr is true, or unsigned int
 * otherwise.
 * Note that uintptr_type is more restrictive than C99 uintptr_t,
 * where an integral type with size greater than that of void *
 * would be conformant.
 */

template<int N>struct uintptr_candidates;
template<>struct uintptr_candidates<-1>{typedef unsigned int       type;};
template<>struct uintptr_candidates<0> {typedef unsigned int       type;};
template<>struct uintptr_candidates<1> {typedef unsigned short     type;};
template<>struct uintptr_candidates<2> {typedef unsigned long      type;};

#if defined(BOOST_HAS_LONG_LONG)
template<>struct uintptr_candidates<3> {typedef unsigned long long type;};
#else
template<>struct uintptr_candidates<3> {typedef unsigned int       type;};
#endif

struct uintptr_aux
{
  BOOST_STATIC_CONSTANT(int,index=
    sizeof(void*)==sizeof(uintptr_candidates<0>::type)?0:
    sizeof(void*)==sizeof(uintptr_candidates<1>::type)?1:
    sizeof(void*)==sizeof(uintptr_candidates<2>::type)?2:
    sizeof(void*)==sizeof(uintptr_candidates<3>::type)?3:-1);

  BOOST_STATIC_CONSTANT(bool,has_uintptr_type=(index>=0));

  typedef uintptr_candidates<index>::type type;
};

typedef mpl::bool_<uintptr_aux::has_uintptr_type> has_uintptr_type;
typedef uintptr_aux::type                         uintptr_type;

} /* namespace multi_index::detail */

} /* namespace multi_index */

} /* namespace boost */

#endif
