// -*- C++ -*-
-// Copyright (C) 2007-2020 Free Software Foundation, Inc.
+// Copyright (C) 2007-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the terms
_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)
+ // 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 <limits> 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<typename _Tp>
+ struct __is_integer_nonstrict
+ : public std::__is_integer<_Tp>
+ {
+ using std::__is_integer<_Tp>::__value;
-#define __glibcxx_max(_Tp) \
- (__glibcxx_signed(_Tp) ? \
- (((((_Tp)1 << (__glibcxx_digits(_Tp) - 1)) - 1) << 1) + 1) : ~(_Tp)0)
+ // The number of bits in the value representation.
+ enum { __width = __value ? sizeof(_Tp) * __CHAR_BIT__ : 0 };
+ };
template<typename _Value>
struct __numeric_traits_integer
{
#if __cplusplus >= 201103L
- static_assert(std::__is_integer<_Value>::__value,
+ static_assert(__is_integer_nonstrict<_Value>::__value,
"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 also available in std::numeric_limits as compile
- // time constants, but <limits> is big and we avoid including it.
- static const bool __is_signed = __glibcxx_signed(_Value);
- static const int __digits = __glibcxx_digits(_Value);
+ // NB: these two are also available in std::numeric_limits as compile
+ // time constants, but <limits> 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;
+
+ // 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<typename _Value>
template<typename _Value>
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<T> \
+ { \
+ enum { __value = 1 }; \
+ typedef std::__true_type __type; \
+ enum { __width = WIDTH }; \
+ }; \
+ template<> struct __is_integer_nonstrict<unsigned T> \
+ { \
+ 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<integer-type>.
template<typename _Tp>
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)
__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<typename _Value>
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...
template<typename _Value>
const int __numeric_traits_floating<_Value>::__max_exponent10;
+#undef __glibcxx_floating
+#undef __glibcxx_max_digits10
+#undef __glibcxx_digits10
+#undef __glibcxx_max_exponent10
+
template<typename _Value>
struct __numeric_traits
- : public __conditional_type<std::__is_integer<_Value>::__value,
- __numeric_traits_integer<_Value>,
- __numeric_traits_floating<_Value> >::__type
+ : public __numeric_traits_integer<_Value>
+ { };
+
+ template<>
+ struct __numeric_traits<float>
+ : public __numeric_traits_floating<float>
{ };
+ template<>
+ struct __numeric_traits<double>
+ : public __numeric_traits_floating<double>
+ { };
+
+ template<>
+ struct __numeric_traits<long double>
+ : public __numeric_traits_floating<long double>
+ { };
+
+#ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
+# if defined __LONG_DOUBLE_IEEE128__
+ // long double is __ieee128, define traits for __ibm128
+ template<>
+ struct __numeric_traits_floating<__ibm128>
+ {
+ static const int __max_digits10 = 33;
+ static const bool __is_signed = true;
+ static const int __digits10 = 31;
+ static const int __max_exponent10 = 308;
+ };
+ template<>
+ struct __numeric_traits<__ibm128>
+ : public __numeric_traits_floating<__ibm128>
+ { };
+# elif defined __LONG_DOUBLE_IBM128__
+ // long double is __ibm128, define traits for __ieee128
+ template<>
+ struct __numeric_traits_floating<__ieee128>
+ {
+ static const int __max_digits10 = 36;
+ static const bool __is_signed = true;
+ static const int __digits10 = 33;
+ static const int __max_exponent10 = 4932;
+ };
+ template<>
+ struct __numeric_traits<__ieee128>
+ : public __numeric_traits_floating<__ieee128>
+ { };
+# endif
+#endif
+
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
-#undef __glibcxx_floating
-#undef __glibcxx_max_digits10
-#undef __glibcxx_digits10
-#undef __glibcxx_max_exponent10
-
-#endif
+#endif
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