/usr/include/boost/detail
Edit: /usr/include/boost/detail/numeric_traits.hpp (5490B)
// (C) Copyright David Abrahams 2001.
// (C) Copyright Howard Hinnant 2001.
//
// 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)
//
// Template class numeric_traits
--
//
// Supplies:
//
// typedef difference_type -- a type used to represent the difference
// between any two values of Number.
//
// Support:
// 1. Not all specializations are supplied
//
// 2. Use of specializations that are not supplied will cause a
// compile-time error
//
// 3. Users are free to specialize numeric_traits for any type.
//
// 4. Right now, specializations are only supplied for integer types.
//
// 5. On implementations which do not supply compile-time constants in
// std::numeric_limits<>, only specializations for built-in integer types
// are supplied.
//
// 6. Handling of numbers whose range of representation is at least as
// great as boost::intmax_t can cause some differences to be
// unrepresentable in difference_type:
//
// Number difference_type
// ------ ---------------
// signed Number
// unsigned intmax_t
//
// template typename numeric_traits::difference_type
// numeric_distance(Number x, Number y)
// computes (y - x), attempting to avoid overflows.
//
// See http://www.boost.org for most recent version including documentation.
// Revision History
// 11 Feb 2001 - Use BOOST_STATIC_CONSTANT (David Abrahams)
// 11 Feb 2001 - Rolled back ineffective Borland-specific code
// (David Abrahams)
// 10 Feb 2001 - Rolled in supposed Borland fixes from John Maddock, but
// not seeing any improvement yet (David Abrahams)
// 06 Feb 2001 - Factored if_true out into boost/detail/select_type.hpp
// (David Abrahams)
// 23 Jan 2001 - Fixed logic of difference_type selection, which was
// completely wack. In the process, added digit_traits<>
// to compute the number of digits in intmax_t even when
// not supplied by numeric_limits<>. (David Abrahams)
// 21 Jan 2001 - Created (David Abrahams)
#ifndef BOOST_NUMERIC_TRAITS_HPP_DWA20001901
#define BOOST_NUMERIC_TRAITS_HPP_DWA20001901
#include
#include
#include
#include
#include
#include
#ifdef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
#include
#include
#endif
namespace boost { namespace detail {
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
// digit_traits - compute the number of digits in a built-in integer
// type. Needed for implementations on which numeric_limits is not specialized
// for some integer types, like __int128 in libstdc++ (gcc).
template ::is_specialized>
struct digit_traits
{
BOOST_STATIC_CONSTANT(int, digits = std::numeric_limits::digits);
};
// numeric_limits is not specialized; compute digits from sizeof(T)
template
struct digit_traits
{
BOOST_STATIC_CONSTANT(int, digits = (
sizeof(T) * std::numeric_limits::digits
- (boost::is_signed::value ? 1 : 0))
);
};
#endif
// Template class integer_traits -- traits of various integer types
// This should probably be rolled into boost::integer_traits one day, but I
// need it to work without
template
struct integer_traits
{
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
private:
typedef Integer integer_type;
typedef std::numeric_limits x;
public:
typedef typename boost::conditional<
(int(x::is_signed)
&& (!int(x::is_bounded)
// digits is the number of no-sign bits
|| (int(x::digits) + 1 >= digit_traits::digits))),
Integer,
typename boost::conditional<
(int(x::digits) + 1 < digit_traits::digits),
signed int,
typename boost::conditional<
(int(x::digits) + 1 < digit_traits::digits),
signed long,
boost::intmax_t
>::type
>::type
>::type difference_type;
#else
BOOST_STATIC_ASSERT(boost::is_integral::value);
typedef typename boost::conditional<
(sizeof(Integer) >= sizeof(intmax_t)),
boost::conditional<
(boost::is_signed::value),
Integer,
boost::intmax_t
>,
boost::conditional<
(sizeof(Integer) < sizeof(std::ptrdiff_t)),
std::ptrdiff_t,
boost::intmax_t
>
>::type::type difference_type;
#endif
};
// Right now, only supports integers, but should be expanded.
template
struct numeric_traits
{
typedef typename integer_traits::difference_type difference_type;
};
template
inline BOOST_CONSTEXPR typename numeric_traits::difference_type numeric_distance(Number x, Number y)
{
typedef typename numeric_traits::difference_type difference_type;
return difference_type(y) - difference_type(x);
}
}}
#endif // BOOST_NUMERIC_TRAITS_HPP_DWA20001901