//  boost integer.hpp header file  -------------------------------------------//

//  Copyright Beman Dawes and Daryle Walker 1999.  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/integer for documentation.

//  Revision History

//   22 Sep 01  Added value-based integer templates. (Daryle Walker)

//   01 Apr 01  Modified to use new <boost/limits.hpp> header. (John Maddock)

//   30 Jul 00  Add typename syntax fix (Jens Maurer)

//   28 Aug 99  Initial version

#ifndef BOOST_INTEGER_HPP

#define BOOST_INTEGER_HPP

#include <boost/integer_fwd.hpp>  // self include

#include <boost/integer_traits.hpp>  // for boost::integer_traits

#include <boost/limits.hpp>          // for std::numeric_limits

namespace boost

{

  //  Helper templates  ------------------------------------------------------//

  //  fast integers from least integers

  //  int_fast_t<> works correctly for unsigned too, in spite of the name.

  template< typename LeastInt >

  struct int_fast_t { typedef LeastInt fast; }; // imps may specialize

  //  convert category to type 

  template< int Category > struct int_least_helper {}; // default is empty

  //  specializatons: 1=long, 2=int, 3=short, 4=signed char,

  //     6=unsigned long, 7=unsigned int, 8=unsigned short, 9=unsigned long

  //  no specializations for 0 and 5: requests for a type > long are in error

  template<> struct int_least_helper<1> { typedef long least; };

  template<> struct int_least_helper<2> { typedef int least; };

  template<> struct int_least_helper<3> { typedef short least; };

  template<> struct int_least_helper<4> { typedef signed char least; };

  template<> struct int_least_helper<6> { typedef unsigned long least; };

  template<> struct int_least_helper<7> { typedef unsigned int least; };

  template<> struct int_least_helper<8> { typedef unsigned short least; };

  template<> struct int_least_helper<9> { typedef unsigned char least; };

  //  integer templates specifying number of bits  ---------------------------//

  //  signed

  template< int Bits >   // bits (including sign) required

  struct int_t 

  {

      typedef typename int_least_helper

        <

          (Bits-1 <= std::numeric_limits<long>::digits) +

          (Bits-1 <= std::numeric_limits<int>::digits) +

          (Bits-1 <= std::numeric_limits<short>::digits) +

          (Bits-1 <= std::numeric_limits<signed char>::digits)

        >::least  least;

      typedef typename int_fast_t<least>::fast  fast;

  };

  //  unsigned

  template< int Bits >   // bits required

  struct uint_t 

  {

      typedef typename int_least_helper

        < 

          5 +

          (Bits <= std::numeric_limits<unsigned long>::digits) +

          (Bits <= std::numeric_limits<unsigned int>::digits) +

          (Bits <= std::numeric_limits<unsigned short>::digits) +

          (Bits <= std::numeric_limits<unsigned char>::digits)

        >::least  least;

      typedef typename int_fast_t<least>::fast  fast;

      // int_fast_t<> works correctly for unsigned too, in spite of the name.

  };

  //  integer templates specifying extreme value  ----------------------------//

  //  signed

  template< long MaxValue >   // maximum value to require support

  struct int_max_value_t 

  {

      typedef typename int_least_helper

        <

          (MaxValue <= integer_traits<long>::const_max) +

          (MaxValue <= integer_traits<int>::const_max) +

          (MaxValue <= integer_traits<short>::const_max) +

          (MaxValue <= integer_traits<signed char>::const_max)

        >::least  least;

      typedef typename int_fast_t<least>::fast  fast;

  };

  template< long MinValue >   // minimum value to require support

  struct int_min_value_t 

  {

      typedef typename int_least_helper

        <

          (MinValue >= integer_traits<long>::const_min) +

          (MinValue >= integer_traits<int>::const_min) +

          (MinValue >= integer_traits<short>::const_min) +

          (MinValue >= integer_traits<signed char>::const_min)

        >::least  least;

      typedef typename int_fast_t<least>::fast  fast;

  };

  //  unsigned

  template< unsigned long Value >   // maximum value to require support

  struct uint_value_t 

  {

      typedef typename int_least_helper

        < 

          5 +

          (Value <= integer_traits<unsigned long>::const_max) +

          (Value <= integer_traits<unsigned int>::const_max) +

          (Value <= integer_traits<unsigned short>::const_max) +

          (Value <= integer_traits<unsigned char>::const_max)

        >::least  least;

      typedef typename int_fast_t<least>::fast  fast;

  };

} // namespace boost

#endif  // BOOST_INTEGER_HPP