diff --git a/libstdc++-v3/include/ext/numeric_traits.h b/libstdc++-v3/include/ext/numeric_traits.h index 585ecc0ba9f..c29f9f21d1a 100644 --- a/libstdc++-v3/include/ext/numeric_traits.h +++ b/libstdc++-v3/include/ext/numeric_traits.h @@ -39,31 +39,23 @@ namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) _GLIBCXX_BEGIN_NAMESPACE_VERSION // Compile time constants for builtin types. - // In C++98 std::numeric_limits member functions cannot be used for this. -#define __glibcxx_signed(_Tp) ((_Tp)(-1) < 0) -#define __glibcxx_digits(_Tp) \ - (sizeof(_Tp) * __CHAR_BIT__ - __glibcxx_signed(_Tp)) - -#define __glibcxx_min(_Tp) \ - (__glibcxx_signed(_Tp) ? -__glibcxx_max(_Tp) - 1 : (_Tp)0) - -#define __glibcxx_max(_Tp) \ - (__glibcxx_signed(_Tp) ? \ - (((((_Tp)1 << (__glibcxx_digits(_Tp) - 1)) - 1) << 1) + 1) : ~(_Tp)0) + // In C++98 std::numeric_limits member functions are not constant expressions + // (that changed in C++11 with the addition of 'constexpr'). + // Even for C++11, this header is smaller than and can be used + // when only is_signed, digits, min, or max values are needed for integers, + // or is_signed, digits10, max_digits10, or max_exponent10 for floats. + // Unlike __is_integer (and std::is_integral) this trait is true for + // non-standard built-in integer types such as __int128 and __int20. template struct __is_integer_nonstrict : public std::__is_integer<_Tp> - { }; + { + using std::__is_integer<_Tp>::__value; -#if defined __STRICT_ANSI__ && defined __SIZEOF_INT128__ - // __is_integer<__int128> is false, but we still want to allow it here. - template<> struct __is_integer_nonstrict<__int128> - { enum { __value = 1 }; typedef std::__true_type __type; }; - - template<> struct __is_integer_nonstrict - { enum { __value = 1 }; typedef std::__true_type __type; }; -#endif + // The number of bits in the value representation. + enum { __width = __value ? sizeof(_Tp) * __CHAR_BIT__ : 0 }; + }; template struct __numeric_traits_integer @@ -73,14 +65,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION "invalid specialization"); #endif - // Only integers for initialization of member constant. - static const _Value __min = __glibcxx_min(_Value); - static const _Value __max = __glibcxx_max(_Value); + // NB: these two are also available in std::numeric_limits as compile + // time constants, but is big and we can avoid including it. + static const bool __is_signed = (_Value)(-1) < 0; + static const int __digits + = __is_integer_nonstrict<_Value>::__width - __is_signed; - // NB: these two also available in std::numeric_limits as compile - // time constants, but is big and we avoid including it. - static const bool __is_signed = __glibcxx_signed(_Value); - static const int __digits = __glibcxx_digits(_Value); + // The initializers must be constants so that __max and __min are too. + static const _Value __max = __is_signed + ? (((((_Value)1 << (__digits - 1)) - 1) << 1) + 1) + : ~(_Value)0; + static const _Value __min = __is_signed ? -__max - 1 : (_Value)0; }; template @@ -95,16 +90,52 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template const int __numeric_traits_integer<_Value>::__digits; + // Enable __numeric_traits_integer for types where the __is_integer_nonstrict + // primary template doesn't give the right answer. +#define _GLIBCXX_INT_N_TRAITS(T, WIDTH) \ + template<> struct __is_integer_nonstrict \ + { \ + enum { __value = 1 }; \ + typedef std::__true_type __type; \ + enum { __width = WIDTH }; \ + }; \ + template<> struct __is_integer_nonstrict \ + { \ + enum { __value = 1 }; \ + typedef std::__true_type __type; \ + enum { __width = WIDTH }; \ + }; + + // We need to specify the width for some __intNN types because they + // have padding bits, e.g. the object representation of __int20 has 32 bits, + // but its width (number of bits in the value representation) is only 20. +#if defined __GLIBCXX_TYPE_INT_N_0 && __GLIBCXX_BITSIZE_INT_N_0 % __CHAR_BIT__ + _GLIBCXX_INT_N_TRAITS(__GLIBCXX_TYPE_INT_N_0, __GLIBCXX_BITSIZE_INT_N_0) +#endif +#if defined __GLIBCXX_TYPE_INT_N_1 && __GLIBCXX_BITSIZE_INT_N_1 % __CHAR_BIT__ + _GLIBCXX_INT_N_TRAITS(__GLIBCXX_TYPE_INT_N_1, __GLIBCXX_BITSIZE_INT_N_1) +#endif +#if defined __GLIBCXX_TYPE_INT_N_2 && __GLIBCXX_BITSIZE_INT_N_2 % __CHAR_BIT__ + _GLIBCXX_INT_N_TRAITS(__GLIBCXX_TYPE_INT_N_2, __GLIBCXX_BITSIZE_INT_N_2) +#endif +#if defined __GLIBCXX_TYPE_INT_N_3 && __GLIBCXX_BITSIZE_INT_N_3 % __CHAR_BIT__ + _GLIBCXX_INT_N_TRAITS(__GLIBCXX_TYPE_INT_N_3, __GLIBCXX_BITSIZE_INT_N_3) +#endif + +#if defined __STRICT_ANSI__ && defined __SIZEOF_INT128__ + // In strict modes __is_integer<__int128> is false, + // but we still want to define __numeric_traits_integer<__int128>. + _GLIBCXX_INT_N_TRAITS(__int128, 128) +#endif + +#undef _GLIBCXX_INT_N_TRAITS + #if __cplusplus >= 201103L + /// Convenience alias for __numeric_traits. template using __int_traits = __numeric_traits_integer<_Tp>; #endif -#undef __glibcxx_signed -#undef __glibcxx_digits -#undef __glibcxx_min -#undef __glibcxx_max - #define __glibcxx_floating(_Tp, _Fval, _Dval, _LDval) \ (std::__are_same<_Tp, float>::__value ? _Fval \ : std::__are_same<_Tp, double>::__value ? _Dval : _LDval) @@ -120,10 +151,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION __glibcxx_floating(_Tp, __FLT_MAX_10_EXP__, __DBL_MAX_10_EXP__, \ __LDBL_MAX_10_EXP__) + // N.B. this only supports float, double and long double (no __float128 etc.) template struct __numeric_traits_floating { - // Only floating point types. See N1822. + // Only floating point types. See N1822. static const int __max_digits10 = __glibcxx_max_digits10(_Value); // See above comment... @@ -159,4 +191,4 @@ _GLIBCXX_END_NAMESPACE_VERSION #undef __glibcxx_digits10 #undef __glibcxx_max_exponent10 -#endif +#endif