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Better fix for SF:1358600

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[SVN r36762]
This commit is contained in:
Alexander Nasonov
2007-01-20 13:16:40 +00:00
parent cf477316ed
commit 209644c177
1 changed files with 20 additions and 25 deletions
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45
include/boost/detail/lcast_precision.hpp
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@@ -15,7 +15,9 @@
#include <boost/config.hpp>
#include <boost/integer_traits.hpp>
#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1400)) // VC++ 8.0
#ifndef BOOST_NO_IS_ABSTRACT
// Fix for SF:1358600 - lexical_cast & pure virtual functions & VC 8 STL
#include <boost/mpl/if.hpp>
#include <boost/type_traits/is_abstract.hpp>
#endif
@@ -27,26 +29,7 @@
namespace boost { namespace detail {
#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1400))
template<class T, bool IsAbstract> struct lcast_msvc_limits;
template<class T>
struct lcast_msvc_limits<T,false>
: std::numeric_limits<T>
{
};
// Non-abstract class that does define a specialization of numeric_limits:
class lcast_msvc_without_limits {};
template<class T>
struct lcast_msvc_limits<T,true>
: std::numeric_limits<lcast_msvc_without_limits>
{
};
#endif // VC++ workaround
class lcast_abstract_stub {};
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
// Calculate an argument to pass to std::ios_base::precision from
@@ -55,10 +38,14 @@ struct lcast_msvc_limits<T,true>
template<class T>
struct lcast_precision
{
#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1400))
typedef lcast_msvc_limits<T, (boost::is_abstract<T>::value)> limits;
#ifdef BOOST_NO_IS_ABSTRACT
typedef std::numeric_limits<T> limits; // No fix for SF:1358600.
#else
typedef std::numeric_limits<T> limits;
typedef BOOST_DEDUCED_TYPENAME boost::mpl::if_<
boost::is_abstract<T>
, std::numeric_limits<lcast_abstract_stub>
, std::numeric_limits<T>
>::type limits;
#endif
BOOST_STATIC_CONSTANT(bool, use_default_precision =
@@ -109,7 +96,15 @@ inline std::streamsize lcast_get_precision(T* = 0)
return lcast_precision<T>::value;
#else // Follow lcast_precision algorithm at run-time:
typedef std::numeric_limits<T> limits;
#ifdef BOOST_NO_IS_ABSTRACT
typedef std::numeric_limits<T> limits; // No fix for SF:1358600.
#else
typedef BOOST_DEDUCED_TYPENAME boost::mpl::if_<
boost::is_abstract<T>
, std::numeric_limits<lcast_abstract_stub>
, std::numeric_limits<T>
>::type limits;
#endif
bool const use_default_precision =
!limits::is_specialized || limits::is_exact;