mirror of
https://github.com/vdemydiuk/mtapi.git
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Viacheslav Demydiuk
109 lines
3.1 KiB
C++
Executable File
109 lines
3.1 KiB
C++
Executable File
// Copyright Alexander Nasonov & Paul A. Bristow 2006.
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// Use, modification and distribution are subject to the
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// Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt
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// or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_DETAIL_LCAST_PRECISION_HPP_INCLUDED
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#define BOOST_DETAIL_LCAST_PRECISION_HPP_INCLUDED
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#include <climits>
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#include <ios>
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#include <limits>
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#include <boost/config.hpp>
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#include <boost/integer_traits.hpp>
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#ifndef BOOST_NO_IS_ABSTRACT
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// Fix for SF:1358600 - lexical_cast & pure virtual functions & VC 8 STL
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#include <boost/type_traits/conditional.hpp>
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#include <boost/type_traits/is_abstract.hpp>
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#endif
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namespace boost { namespace detail {
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class lcast_abstract_stub {};
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// Calculate an argument to pass to std::ios_base::precision from
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// lexical_cast. See alternative implementation for broken standard
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// libraries in lcast_get_precision below. Keep them in sync, please.
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template<class T>
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struct lcast_precision
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{
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#ifdef BOOST_NO_IS_ABSTRACT
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typedef std::numeric_limits<T> limits; // No fix for SF:1358600.
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#else
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typedef typename boost::conditional<
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boost::is_abstract<T>::value
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, std::numeric_limits<lcast_abstract_stub>
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, std::numeric_limits<T>
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>::type limits;
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#endif
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BOOST_STATIC_CONSTANT(bool, use_default_precision =
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!limits::is_specialized || limits::is_exact
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);
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BOOST_STATIC_CONSTANT(bool, is_specialized_bin =
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!use_default_precision &&
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limits::radix == 2 && limits::digits > 0
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);
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BOOST_STATIC_CONSTANT(bool, is_specialized_dec =
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!use_default_precision &&
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limits::radix == 10 && limits::digits10 > 0
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);
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BOOST_STATIC_CONSTANT(std::streamsize, streamsize_max =
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boost::integer_traits<std::streamsize>::const_max
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);
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BOOST_STATIC_CONSTANT(unsigned int, precision_dec = limits::digits10 + 1U);
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static_assert(!is_specialized_dec ||
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precision_dec <= streamsize_max + 0UL
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, "");
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BOOST_STATIC_CONSTANT(unsigned long, precision_bin =
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2UL + limits::digits * 30103UL / 100000UL
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);
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static_assert(!is_specialized_bin ||
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(limits::digits + 0UL < ULONG_MAX / 30103UL &&
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precision_bin > limits::digits10 + 0UL &&
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precision_bin <= streamsize_max + 0UL)
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, "");
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BOOST_STATIC_CONSTANT(std::streamsize, value =
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is_specialized_bin ? precision_bin
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: is_specialized_dec ? precision_dec : 6
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);
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};
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template<class T>
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inline std::streamsize lcast_get_precision(T* = 0)
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{
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return lcast_precision<T>::value;
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}
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template<class T>
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inline void lcast_set_precision(std::ios_base& stream, T*)
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{
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stream.precision(lcast_get_precision<T>());
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}
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template<class Source, class Target>
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inline void lcast_set_precision(std::ios_base& stream, Source*, Target*)
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{
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std::streamsize const s = lcast_get_precision(static_cast<Source*>(0));
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std::streamsize const t = lcast_get_precision(static_cast<Target*>(0));
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stream.precision(s > t ? s : t);
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}
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}}
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#endif // BOOST_DETAIL_LCAST_PRECISION_HPP_INCLUDED
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