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Fix numeric_cast<> bugs with floating types.

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[SVN r8008]
This commit is contained in:
Dave Abrahams
2000-10-19 19:14:03 +00:00
parent 906d09b511
commit 7470535162
1 changed files with 66 additions and 7 deletions
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71
include/boost/cast.hpp
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@@ -9,6 +9,7 @@
// See http://www.boost.org for most recent version including documentation.
// Revision History
// 19 Oct 00 Fix numeric_cast for floating-point types (Dave Abrahams)
// 15 Jul 00 Suppress numeric_cast warnings for GCC, Borland and MSVC (Dave Abrahams)
// 30 Jun 00 More MSVC6 wordarounds. See comments below. (Dave Abrahams)
// 28 Jun 00 Removed implicit_cast<>. See comment below. (Beman Dawes)
@@ -124,6 +125,42 @@ namespace boost
#endif
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
namespace detail
{
template <bool is_signed> struct numeric_min_select;
template<>
struct numeric_min_select<true>
{
template <class T>
struct limits : std::numeric_limits<T>
{
static inline T min()
{
return std::numeric_limits<T>::min() >= 0
// unary minus causes integral promotion, thus the static_cast<>
? static_cast<T>(-std::numeric_limits<T>::max())
: std::numeric_limits<T>::min();
}
};
};
template<>
struct numeric_min_select<false>
{
template <class T>
struct limits : std::numeric_limits<T> {};
};
// Move to namespace boost in utility.hpp?
template <class T>
struct fixed_numeric_limits
: public numeric_min_select<std::numeric_limits<T>::is_signed>::limits<T>
{
};
}
// less_than_type_min -
// x_is_signed should be numeric_limits<X>::is_signed
// y_is_signed should be numeric_limits<Y>::is_signed
@@ -204,6 +241,30 @@ namespace boost
static inline bool check(X x, Y)
{ return static_cast<X>(static_cast<Y>(x)) != x; }
};
#else // use #pragma hacks if available
namespace detail {
# if BOOST_MSVC
# pragma warning(push)
# pragma warning(disable : 4018)
# pragma warning(disable : 4146)
# endif
// Move to namespace boost in utility.hpp?
template <class T>
struct fixed_numeric_limits : public std::numeric_limits<T>
{
static inline T min()
{
return std::numeric_limits<T>::is_signed && std::numeric_limits<T>::min() >= 0
? -std::numeric_limits<T>::max() : std::numeric_limits<T>::min();
}
};
# if BOOST_MSVC
# pragma warning(pop)
# endif
}
#endif
template<typename Target, typename Source>
@@ -211,7 +272,7 @@ namespace boost
{
// typedefs abbreviating respective trait classes
typedef std::numeric_limits<Source> arg_traits;
typedef std::numeric_limits<Target> result_traits;
typedef detail::fixed_numeric_limits<Target> result_traits;
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
// typedefs that act as compile time assertions
@@ -234,10 +295,9 @@ namespace boost
# pragma warning(push)
# pragma warning(disable : 4018)
# endif
if ( (arg < 0 && !result_traits::is_signed) || // loss of negative range
(arg_traits::is_signed &&
arg < result_traits::min()) || // underflow
arg > result_traits::max() ) // overflow
if ((arg < 0 && !result_traits::is_signed) // loss of negative range
|| (arg_traits::is_signed && arg < result_traits::min()) // underflow
|| arg > result_traits::max()) // overflow
# if BOOST_MSVC
# pragma warning(pop)
# endif
@@ -272,4 +332,3 @@ namespace boost
} // namespace boost
#endif // BOOST_CAST_HPP