libstdc++-v3/include/ext/numeric_traits.h - gcc - Git at Google

 // -*- C++ -*-

 // 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
 // of the GNU General Public License as published by the Free Software
 // Foundation; either version 3, or (at your option) any later
 // version.

 // This library is distributed in the hope that it will be useful, but
 // WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 // General Public License for more details.

 // Under Section 7 of GPL version 3, you are granted additional
 // permissions described in the GCC Runtime Library Exception, version
 // 3.1, as published by the Free Software Foundation.

 // You should have received a copy of the GNU General Public License and
 // a copy of the GCC Runtime Library Exception along with this program;
 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 // <http://www.gnu.org/licenses/>.

 /** @file ext/numeric_traits.h
  *  This file is a GNU extension to the Standard C++ Library.
  */

 #ifndef _EXT_NUMERIC_TRAITS
 #define _EXT_NUMERIC_TRAITS 1

 #pragma GCC system_header

 #include <bits/cpp_type_traits.h>
 #include <ext/type_traits.h>

 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION

   // Compile time constants for builtin types.
   // 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;

       // 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(__is_integer_nonstrict<_Value>::__value,
 		    "invalid specialization");
 #endif

       // 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>
     const _Value __numeric_traits_integer<_Value>::__min;

   template<typename _Value>
     const _Value __numeric_traits_integer<_Value>::__max;

   template<typename _Value>
     const bool __numeric_traits_integer<_Value>::__is_signed;

   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)			\
   __extension__						\
   template<> struct __is_integer_nonstrict<T>		\
   {							\
     enum { __value = 1 };				\
     typedef std::__true_type __type;			\
     enum { __width = WIDTH };				\
   };							\
   __extension__						\
   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

 #define __glibcxx_floating(_Tp, _Fval, _Dval, _LDval) \
   (std::__are_same<_Tp, float>::__value ? _Fval \
    : std::__are_same<_Tp, double>::__value ? _Dval : _LDval)

 #define __glibcxx_max_digits10(_Tp) \
   (2 + __glibcxx_floating(_Tp, __FLT_MANT_DIG__, __DBL_MANT_DIG__, \
 			  __LDBL_MANT_DIG__) * 643L / 2136)

 #define __glibcxx_digits10(_Tp) \
   __glibcxx_floating(_Tp, __FLT_DIG__, __DBL_DIG__, __LDBL_DIG__)

 #define __glibcxx_max_exponent10(_Tp) \
   __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.
       static const int __max_digits10 = __glibcxx_max_digits10(_Value);

       // See above comment...
       static const bool __is_signed = true;
       static const int __digits10 = __glibcxx_digits10(_Value);
       static const int __max_exponent10 = __glibcxx_max_exponent10(_Value);
     };

   template<typename _Value>
     const int __numeric_traits_floating<_Value>::__max_digits10;

   template<typename _Value>
     const bool __numeric_traits_floating<_Value>::__is_signed;

   template<typename _Value>
     const int __numeric_traits_floating<_Value>::__digits10;

   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 __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

 #endif
	// -- C++ --

	// 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
	// of the GNU General Public License as published by the Free Software
	// Foundation; either version 3, or (at your option) any later
	// version.

	// This library is distributed in the hope that it will be useful, but
	// WITHOUT ANY WARRANTY; without even the implied warranty of
	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	// General Public License for more details.

	// Under Section 7 of GPL version 3, you are granted additional
	// permissions described in the GCC Runtime Library Exception, version
	// 3.1, as published by the Free Software Foundation.

	// You should have received a copy of the GNU General Public License and
	// a copy of the GCC Runtime Library Exception along with this program;
	// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
	// <http://www.gnu.org/licenses/>.

	/** @file ext/numeric_traits.h
	* This file is a GNU extension to the Standard C++ Library.
	*/

	#ifndef _EXT_NUMERIC_TRAITS
	#define _EXT_NUMERIC_TRAITS 1

	#pragma GCC system_header

	#include <bits/cpp_type_traits.h>
	#include <ext/type_traits.h>

	namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
	{
	_GLIBCXX_BEGIN_NAMESPACE_VERSION

	// Compile time constants for builtin types.
	// 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;

	// 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(__is_integer_nonstrict<_Value>::__value,
	"invalid specialization");
	#endif

	// 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>
	const _Value __numeric_traits_integer<_Value>::__min;

	template<typename _Value>
	const _Value __numeric_traits_integer<_Value>::__max;

	template<typename _Value>
	const bool __numeric_traits_integer<_Value>::__is_signed;

	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) \
	__extension__ \
	template<> struct __is_integer_nonstrict<T> \
	{ \
	enum { __value = 1 }; \
	typedef std::__true_type __type; \
	enum { __width = WIDTH }; \
	}; \
	__extension__ \
	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

	#define __glibcxx_floating(_Tp, _Fval, _Dval, _LDval) \
	(std::__are_same<_Tp, float>::__value ? _Fval \
	: std::__are_same<_Tp, double>::__value ? _Dval : _LDval)

	#define __glibcxx_max_digits10(_Tp) \
	(2 + __glibcxx_floating(_Tp, __FLT_MANT_DIG__, __DBL_MANT_DIG__, \
	__LDBL_MANT_DIG__) * 643L / 2136)

	#define __glibcxx_digits10(_Tp) \
	__glibcxx_floating(_Tp, __FLT_DIG__, __DBL_DIG__, __LDBL_DIG__)

	#define __glibcxx_max_exponent10(_Tp) \
	__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.
	static const int __max_digits10 = __glibcxx_max_digits10(_Value);

	// See above comment...
	static const bool __is_signed = true;
	static const int __digits10 = __glibcxx_digits10(_Value);
	static const int __max_exponent10 = __glibcxx_max_exponent10(_Value);
	};

	template<typename _Value>
	const int __numeric_traits_floating<_Value>::__max_digits10;

	template<typename _Value>
	const bool __numeric_traits_floating<_Value>::__is_signed;

	template<typename _Value>
	const int __numeric_traits_floating<_Value>::__digits10;

	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 __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

	#endif