boostorg/conversion
1
0
Fork 1
mirror of https://github.com/boostorg/conversion.git synced 2025-08-02 14:04:28 +02:00
Code Issues Packages Projects Releases Wiki Activity

a fix for "unsigned type always passes this test" warnings under GCC.

Browse Source 
[SVN r7999]
This commit is contained in:
Dave Abrahams
2000-10-18 13:52:09 +00:00
parent 15539c72c8
commit 906d09b511
1 changed files with 24 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
include/boost/cast.hpp
View File

@@ -166,26 +166,44 @@ namespace boost
// between signed and unsigned values. // between signed and unsigned values.
// //
// "poor man's partial specialization" is in use here. // "poor man's partial specialization" is in use here.
template <bool same_sign> template <bool same_sign, bool x_is_signed>
struct greater_than_type_max; struct greater_than_type_max;
template<> template<>
struct greater_than_type_max<true> struct greater_than_type_max<true, true>
{ {
template <class X, class Y> template <class X, class Y>
static bool check(X x, Y y_max) static inline bool check(X x, Y y_max)
{ return x > y_max; } { return x > y_max; }
}; };
template <> template <>
struct greater_than_type_max<false> struct greater_than_type_max<false, true>
{ {
// What does the standard say about this? I think it's right, and it // What does the standard say about this? I think it's right, and it
// will work with every compiler I know of. // will work with every compiler I know of.
template <class X, class Y> template <class X, class Y>
static bool check(X x, Y) static inline bool check(X x, Y)
{ return x >= 0 && static_cast<X>(static_cast<Y>(x)) != x; } { return x >= 0 && static_cast<X>(static_cast<Y>(x)) != x; }
}; };
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; }
};
#endif #endif
template<typename Target, typename Source> template<typename Target, typename Source>
@@ -207,7 +225,7 @@ namespace boost
const bool same_sign = arg_is_signed == result_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()) if (less_than_type_min<arg_is_signed, result_is_signed>::check(arg, result_traits::min())
|| greater_than_type_max<same_sign>::check(arg, result_traits::max()) || greater_than_type_max<same_sign, arg_is_signed>::check(arg, result_traits::max())
) )
#else // We need to use #pragma hacks if available #else // We need to use #pragma hacks if available