feedc0de/boost_conversion
1
0
Fork 0
forked from boostorg/conversion
Code Pull Requests Activity

Old numeric_cast<> completely replaced by new code (except that the old code is retained as a fallback mechanism for old broken compilers that can't deal with the new code)

Browse Source 
[SVN r29761]
This commit is contained in:
Fernando Cacciola
2005-06-23 23:33:01 +00:00
parent e331fc2a21
commit e66d58e6de
4 changed files with 28 additions and 374 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/boost/cast.hpp
+10 -284
View File
@@ -1,6 +1,6 @@
// boost cast.hpp header file ----------------------------------------------//
// (C) Copyright Kevlin Henney and Dave Abrahams 1999.
// (C) Copyright Kevlin Henney and Dave Abrahams 1999.
// 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)
@@ -8,9 +8,10 @@
// See http://www.boost.org/libs/conversion for Documentation.
// Revision History
// 02 Apr 01 Removed BOOST_NO_LIMITS workarounds and included
// <boost/limits.hpp> instead (the workaround did not
// actually compile when BOOST_NO_LIMITS was defined in
// 23 JUn 05 numeric_cast removed and redirected to the new verion (Fernando Cacciola)
// 02 Apr 01 Removed BOOST_NO_LIMITS workarounds and included
// <boost/limits.hpp> instead (the workaround did not
// actually compile when BOOST_NO_LIMITS was defined in
// any case, so we loose nothing). (John Maddock)
// 21 Jan 01 Undid a bug I introduced yesterday. numeric_cast<> never
// worked with stock GCC; trying to get it to do that broke
@@ -26,14 +27,14 @@
// (Dave Abrahams)
// 30 Jun 00 More MSVC6 wordarounds. See comments below. (Dave Abrahams)
// 28 Jun 00 Removed implicit_cast<>. See comment below. (Beman Dawes)
// 27 Jun 00 More MSVC6 workarounds
// 27 Jun 00 More MSVC6 workarounds
// 15 Jun 00 Add workarounds for MSVC6
// 2 Feb 00 Remove bad_numeric_cast ";" syntax error (Doncho Angelov)
// 26 Jan 00 Add missing throw() to bad_numeric_cast::what(0 (Adam Levar)
// 29 Dec 99 Change using declarations so usages in other namespaces work
// correctly (Dave Abrahams)
// 23 Sep 99 Change polymorphic_downcast assert to also detect M.I. errors
// as suggested Darin Adler and improved by Valentin Bonnard.
// as suggested Darin Adler and improved by Valentin Bonnard.
// 2 Sep 99 Remove controversial asserts, simplify, rename.
// 30 Aug 99 Move to cast.hpp, replace value_cast with numeric_cast,
// place in nested namespace.
@@ -68,7 +69,7 @@ namespace boost
// polymorphic_cast --------------------------------------------------------//
// Runtime checked polymorphic downcasts and crosscasts.
// Suggested in The C++ Programming Language, 3rd Ed, Bjarne Stroustrup,
// Suggested in The C++ Programming Language, 3rd Ed, Bjarne Stroustrup,
// section 15.8 exercise 1, page 425.
template <class Target, class Source>
@@ -98,284 +99,9 @@ namespace boost
// implicit_cast -----------------------------------------------------------//
//
// Removed due to uncertain purpose. Use either numeric_cast (see below)
// or static_cast according to the need.
// or static_cast according to the need.
// numeric_cast and related exception --------------------------------------//
// Contributed by Kevlin Henney
// bad_numeric_cast --------------------------------------------------------//
// exception used to indicate runtime numeric_cast failure
class bad_numeric_cast : public std::bad_cast
{
public:
// constructors, destructors and assignment operator defaulted
// function inlined for brevity and consistency with rest of library
virtual const char *what() const throw()
{
return "bad numeric cast: loss of range in numeric_cast";
}
};
// numeric_cast ------------------------------------------------------------//
#if !defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) || defined(BOOST_SGI_CPP_LIMITS)
namespace detail
{
template <class T>
struct signed_numeric_limits : std::numeric_limits<T>
{
static inline T min BOOST_PREVENT_MACRO_SUBSTITUTION ()
{
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)();
};
};
// Move to namespace boost in utility.hpp?
template <class T, bool specialized>
struct fixed_numeric_limits_base
: public if_true< std::numeric_limits<T>::is_signed >
::BOOST_NESTED_TEMPLATE then< signed_numeric_limits<T>,
std::numeric_limits<T>
>::type
{};
template <class T>
struct fixed_numeric_limits
: fixed_numeric_limits_base<T,(std::numeric_limits<T>::is_specialized)>
{};
# ifdef BOOST_HAS_LONG_LONG
// cover implementations which supply no specialization for long
// long / unsigned long long. Not intended to be full
// numeric_limits replacements, but good enough for numeric_cast<>
template <>
struct fixed_numeric_limits_base< ::boost::long_long_type, false>
{
BOOST_STATIC_CONSTANT(bool, is_specialized = true);
BOOST_STATIC_CONSTANT(bool, is_signed = true);
static ::boost::long_long_type max BOOST_PREVENT_MACRO_SUBSTITUTION ()
{
# ifdef LONGLONG_MAX
return LONGLONG_MAX;
# else
return 9223372036854775807LL; // hope this is portable
# endif
}
static ::boost::long_long_type min BOOST_PREVENT_MACRO_SUBSTITUTION ()
{
# ifdef LONGLONG_MIN
return LONGLONG_MIN;
# else
return -( 9223372036854775807LL )-1; // hope this is portable
# endif
}
};
template <>
struct fixed_numeric_limits_base< ::boost::ulong_long_type, false>
{
BOOST_STATIC_CONSTANT(bool, is_specialized = true);
BOOST_STATIC_CONSTANT(bool, is_signed = false);
static ::boost::ulong_long_type max BOOST_PREVENT_MACRO_SUBSTITUTION ()
{
# ifdef ULONGLONG_MAX
return ULONGLONG_MAX;
# else
return 0xffffffffffffffffULL; // hope this is portable
# endif
}
static ::boost::ulong_long_type min BOOST_PREVENT_MACRO_SUBSTITUTION () { return 0; }
};
# endif
} // namespace detail
// less_than_type_min -
// x_is_signed should be numeric_limits<X>::is_signed
// y_is_signed should be numeric_limits<Y>::is_signed
// y_min should be numeric_limits<Y>::min()
//
// check(x, y_min) returns true iff x < y_min without invoking comparisons
// between signed and unsigned values.
//
// "poor man's partial specialization" is in use here.
template <bool x_is_signed, bool y_is_signed>
struct less_than_type_min
{
template <class X, class Y>
static bool check(X x, Y y_min)
{ return x < y_min; }
};
template <>
struct less_than_type_min<false, true>
{
template <class X, class Y>
static bool check(X, Y)
{ return false; }
};
template <>
struct less_than_type_min<true, false>
{
template <class X, class Y>
static bool check(X x, Y)
{ return x < 0; }
};
// greater_than_type_max -
// same_sign should be:
// numeric_limits<X>::is_signed == numeric_limits<Y>::is_signed
// y_max should be numeric_limits<Y>::max()
//
// check(x, y_max) returns true iff x > y_max without invoking comparisons
// between signed and unsigned values.
//
// "poor man's partial specialization" is in use here.
template <bool same_sign, bool x_is_signed>
struct greater_than_type_max;
template<>
struct greater_than_type_max<true, true>
{
template <class X, class Y>
static inline bool check(X x, Y y_max)
{ return x > y_max; }
};
template <>
struct greater_than_type_max<false, true>
{
// What does the standard say about this? I think it's right, and it
// will work with every compiler I know of.
template <class X, class Y>
static inline bool check(X x, Y)
{ return x >= 0 && static_cast<X>(static_cast<Y>(x)) != x; }
# if defined(BOOST_MSVC) && BOOST_MSVC <= 1200
// MSVC6 can't static_cast unsigned __int64 -> floating types
# define BOOST_UINT64_CAST(src_type) \
static inline bool check(src_type x, unsigned __int64) \
{ \
if (x < 0) return false; \
unsigned __int64 y = static_cast<unsigned __int64>(x); \
bool odd = y & 0x1; \
__int64 div2 = static_cast<__int64>(y >> 1); \
return ((static_cast<src_type>(div2) * 2.0) + odd) != x; \
}
BOOST_UINT64_CAST(long double);
BOOST_UINT64_CAST(double);
BOOST_UINT64_CAST(float);
# undef BOOST_UINT64_CAST
# endif
};
template<>
struct greater_than_type_max<true, false>
{
template <class X, class Y>
static inline bool check(X x, Y y_max)
{ return x > y_max; }
};
template <>
struct greater_than_type_max<false, false>
{
// What does the standard say about this? I think it's right, and it
// will work with every compiler I know of.
template <class X, class Y>
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)
#elif defined(__BORLANDC__)
# pragma option push -w-8041
# endif
// Move to namespace boost in utility.hpp?
template <class T>
struct fixed_numeric_limits : public std::numeric_limits<T>
{
static inline T min BOOST_PREVENT_MACRO_SUBSTITUTION ()
{
return std::numeric_limits<T>::is_signed && (std::numeric_limits<T>::min)() >= 0
? T(-(std::numeric_limits<T>::max)()) : (std::numeric_limits<T>::min)();
}
};
# if BOOST_MSVC
# pragma warning(pop)
#elif defined(__BORLANDC__)
# pragma option pop
# endif
} // namespace detail
#endif
template<typename Target, typename Source>
inline Target numeric_cast(Source arg BOOST_EXPLICIT_DEFAULT_TARGET)
{
// typedefs abbreviating respective trait classes
typedef detail::fixed_numeric_limits<Source> arg_traits;
typedef detail::fixed_numeric_limits<Target> result_traits;
#if defined(BOOST_STRICT_CONFIG) \
|| (!defined(__HP_aCC) || __HP_aCC > 33900) \
&& (!defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) \
|| defined(BOOST_SGI_CPP_LIMITS))
// typedefs that act as compile time assertions
// (to be replaced by boost compile time assertions
// as and when they become available and are stable)
typedef bool argument_must_be_numeric[arg_traits::is_specialized];
typedef bool result_must_be_numeric[result_traits::is_specialized];
const bool arg_is_signed = arg_traits::is_signed;
const bool result_is_signed = result_traits::is_signed;
const bool same_sign = arg_is_signed == result_is_signed;
if (less_than_type_min<arg_is_signed, result_is_signed>::check(arg, (result_traits::min)())
|| greater_than_type_max<same_sign, arg_is_signed>::check(arg, (result_traits::max)())
)
#else // We need to use #pragma hacks if available
# if BOOST_MSVC
# pragma warning(push)
# pragma warning(disable : 4018)
#elif defined(__BORLANDC__)
#pragma option push -w-8012
# 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 BOOST_MSVC
# pragma warning(pop)
#elif defined(__BORLANDC__)
#pragma option pop
# endif
#endif
{
throw bad_numeric_cast();
}
return static_cast<Target>(arg);
} // numeric_cast
#include <boost/numeric/conversion/cast.hpp>
# undef BOOST_EXPLICIT_DEFAULT_TARGET