x
Yes
No
Do you want to visit DriveHQ English website?
首页
产品服务
价格
免费试用
下载客户端
关于我们
云文件服务
|
云备份服务
|
FTP服务
|
企业邮箱服务
|
网站托管
|
客户端软件
云文件服务
云备份服务
FTP服务
企业级邮箱服务
网站托管
客户端软件
numeric_traits.hpp - Hosted on DriveHQ Cloud IT Platform
返回上层目录
上传
下载
共享
发布
新建文件夹
新建文件
复制
剪切
删除
粘贴
评论
升级服务
路径: \\game3dprogramming\materials\GameFactory\GameFactoryDemo\references\boost_1_35_0\boost\detail\numeric_traits.hpp
旋转
特效
属性
历史版本
// (C) Copyright David Abrahams 2001, 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
namespace boost { namespace detail { // Template class is_signed -- determine whether a numeric type is signed // Requires that T is constructable from the literals -1 and 0. Compile-time // error results if that requirement is not met (and thus signedness is not // likely to have meaning for that type). template
struct is_signed { #if defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) || defined(BOOST_MSVC) && BOOST_MSVC <= 1300 BOOST_STATIC_CONSTANT(bool, value = (Number(-1) < Number(0))); #else BOOST_STATIC_CONSTANT(bool, value = std::numeric_limits
::is_signed); #endif }; # 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 intmax_t (e.g. VC6). template
struct digit_traits_select; // numeric_limits is specialized; just select that version of digits template <> struct digit_traits_select
{ template
struct traits { BOOST_STATIC_CONSTANT(int, digits = std::numeric_limits
::digits); }; }; // numeric_limits is not specialized; compute digits from sizeof(T) template <> struct digit_traits_select
{ template
struct traits { BOOST_STATIC_CONSTANT(int, digits = ( sizeof(T) * std::numeric_limits
::digits - (is_signed
::value ? 1 : 0)) ); }; }; // here's the "usable" template template
struct digit_traits { typedef digit_traits_select< ::std::numeric_limits
::is_specialized> selector; typedef typename selector::template traits
traits; BOOST_STATIC_CONSTANT(int, digits = traits::digits); }; #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; # if defined(BOOST_MSVC) && BOOST_MSVC <= 1300 // for some reason, MSVC asserts when it shouldn't unless we make these // local definitions BOOST_STATIC_CONSTANT(bool, is_integer = x::is_integer); BOOST_STATIC_CONSTANT(bool, is_specialized = x::is_specialized); BOOST_STATIC_ASSERT(is_integer); BOOST_STATIC_ASSERT(is_specialized); # endif public: typedef typename if_true<(int(x::is_signed) && (!int(x::is_bounded) // digits is the number of no-sign bits || (int(x::digits) + 1 >= digit_traits
::digits)))>::template then< Integer, typename if_true<(int(x::digits) + 1 < digit_traits
::digits)>::template then< signed int, typename if_true<(int(x::digits) + 1 < digit_traits
::digits)>::template then< signed long, // else intmax_t >::type>::type>::type difference_type; #else BOOST_STATIC_ASSERT(boost::is_integral
::value); typedef typename if_true<(sizeof(Integer) >= sizeof(intmax_t))>::template then< typename if_true<(is_signed
::value)>::template then< Integer, intmax_t >::type, typename if_true<(sizeof(Integer) < sizeof(std::ptrdiff_t))>::template then< std::ptrdiff_t, 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
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
numeric_traits.hpp
网页地址
文件地址
上一页
35/61
下一页
下载
( 6 KB )
Comments
Total ratings:
0
Average rating:
无评论
of 10
Would you like to comment?
Join now
, or
Logon
if you are already a member.