parse_numbers.h
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// Components for compile-time parsing of numbers -*- C++ -*-
// Copyright (C) 2013 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 bits/parse_numbers.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{chrono}
*/
#ifndef _PARSE_NUMBERS_H
#define _PARSE_NUMBERS_H 1
#pragma GCC system_header
// From n3642.pdf except I added binary literals and digit separator '`'.
#if __cplusplus > 201103L
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace __parse_int {
template<unsigned _Base, char _Dig>
struct _Digit;
template<unsigned _Base>
struct _Digit<_Base, '0'>
{
static constexpr bool valid{true};
static constexpr unsigned value{0};
};
template<unsigned _Base>
struct _Digit<_Base, '1'>
{
static constexpr bool valid{true};
static constexpr unsigned value{1};
};
template<unsigned _Base>
struct _Digit<_Base, '2'>
{
static_assert(_Base > 2, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{2};
};
template<unsigned _Base>
struct _Digit<_Base, '3'>
{
static_assert(_Base > 3, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{3};
};
template<unsigned _Base>
struct _Digit<_Base, '4'>
{
static_assert(_Base > 4, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{4};
};
template<unsigned _Base>
struct _Digit<_Base, '5'>
{
static_assert(_Base > 5, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{5};
};
template<unsigned _Base>
struct _Digit<_Base, '6'>
{
static_assert(_Base > 6, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{6};
};
template<unsigned _Base>
struct _Digit<_Base, '7'>
{
static_assert(_Base > 7, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{7};
};
template<unsigned _Base>
struct _Digit<_Base, '8'>
{
static_assert(_Base > 8, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{8};
};
template<unsigned _Base>
struct _Digit<_Base, '9'>
{
static_assert(_Base > 9, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{9};
};
template<unsigned _Base>
struct _Digit<_Base, 'a'>
{
static_assert(_Base > 0xa, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{0xa};
};
template<unsigned _Base>
struct _Digit<_Base, 'A'>
{
static_assert(_Base > 0xa, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{0xa};
};
template<unsigned _Base>
struct _Digit<_Base, 'b'>
{
static_assert(_Base > 0xb, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{0xb};
};
template<unsigned _Base>
struct _Digit<_Base, 'B'>
{
static_assert(_Base > 0xb, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{0xb};
};
template<unsigned _Base>
struct _Digit<_Base, 'c'>
{
static_assert(_Base > 0xc, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{0xc};
};
template<unsigned _Base>
struct _Digit<_Base, 'C'>
{
static_assert(_Base > 0xc, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{0xc};
};
template<unsigned _Base>
struct _Digit<_Base, 'd'>
{
static_assert(_Base > 0xd, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{0xd};
};
template<unsigned _Base>
struct _Digit<_Base, 'D'>
{
static_assert(_Base > 0xd, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{0xd};
};
template<unsigned _Base>
struct _Digit<_Base, 'e'>
{
static_assert(_Base > 0xe, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{0xe};
};
template<unsigned _Base>
struct _Digit<_Base, 'E'>
{
static_assert(_Base > 0xe, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{0xe};
};
template<unsigned _Base>
struct _Digit<_Base, 'f'>
{
static_assert(_Base > 0xf, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{0xf};
};
template<unsigned _Base>
struct _Digit<_Base, 'F'>
{
static_assert(_Base > 0xf, "invalid digit");
static constexpr bool valid{true};
static constexpr unsigned value{0xf};
};
// Digit separator
template<unsigned _Base>
struct _Digit<_Base, '`'>
{
static constexpr bool valid{false};
static constexpr unsigned value{0};
};
//------------------------------------------------------------------------------
template<unsigned _Base, char _Dig, char... _Digs>
struct _Digits_help
{
static constexpr unsigned
value{_Digit<_Base, _Dig>::valid ?
1U + _Digits_help<_Base, _Digs...>::value :
_Digits_help<_Base, _Digs...>::value};
};
template<unsigned _Base, char _Dig>
struct _Digits_help<_Base, _Dig>
{
static constexpr unsigned value{_Digit<_Base, _Dig>::valid ? 1U : 0U};
};
template<unsigned _Base, char... _Digs>
struct _Digits
{
static constexpr unsigned value{_Digits_help<_Base, _Digs...>::value};
};
template<unsigned _Base>
struct _Digits<_Base>
{
static constexpr unsigned value{0U};
};
//------------------------------------------------------------------------------
template<unsigned _Base, char _Dig, char... _Digs>
struct _Power_help
{
static constexpr unsigned
value{_Digit<_Base, _Dig>::valid ?
_Base * _Power_help<_Base, _Digs...>::value :
_Power_help<_Base, _Digs...>::value};
};
template<unsigned _Base, char _Dig>
struct _Power_help<_Base, _Dig>
{
static constexpr unsigned value{_Digit<_Base, _Dig>::valid ? 1U : 0U};
};
template<unsigned _Base, char... _Digs>
struct _Power
{
static constexpr unsigned value{_Power_help<_Base, _Digs...>::value};
};
template<unsigned _Base>
struct _Power<_Base>
{
static constexpr unsigned value{0U};
};
//------------------------------------------------------------------------------
template<unsigned _Base, unsigned _Pow, char _Dig, char... _Digs>
struct _Number_help
{
static constexpr unsigned
value{_Digit<_Base, _Dig>::valid ?
_Pow * _Digit<_Base, _Dig>::value
+ _Number_help<_Base, _Pow / _Base, _Digs...>::value :
_Number_help<_Base, _Pow, _Digs...>::value};
};
template<unsigned _Base, unsigned _Pow, char _Dig>
struct _Number_help<_Base, _Pow, _Dig>
{
//static_assert(_Pow == 1U, "power should be one");
static constexpr unsigned
value{_Digit<_Base, _Dig>::valid ? _Digit<_Base, _Dig>::value : 0U};
};
template<unsigned _Base, char... _Digs>
struct _Number
{
static constexpr unsigned
value{_Number_help<_Base, _Power<_Base, _Digs...>::value,
_Digs...>::value};
};
template<unsigned _Base>
struct _Number<_Base>
{
static constexpr unsigned value{0U};
};
//------------------------------------------------------------------------------
// This _Parse_int is the same 'level' as the old _Base_dispatch.
template<char... _Digs>
struct _Parse_int;
template<char... _Digs>
struct _Parse_int<'0', 'b', _Digs...>
{
static constexpr unsigned long long
value{_Number<2U, _Digs...>::value};
};
template<char... _Digs>
struct _Parse_int<'0', 'B', _Digs...>
{
static constexpr unsigned long long
value{_Number<2U, _Digs...>::value};
};
template<char... _Digs>
struct _Parse_int<'0', 'x', _Digs...>
{
static constexpr unsigned long long
value{_Number<16U, _Digs...>::value};
};
template<char... _Digs>
struct _Parse_int<'0', 'X', _Digs...>
{
static constexpr unsigned long long
value{_Number<16U, _Digs...>::value};
};
template<char... _Digs>
struct _Parse_int<'0', _Digs...>
{
static constexpr unsigned long long
value{_Number<8U, _Digs...>::value};
};
template<char... _Digs>
struct _Parse_int
{
static constexpr unsigned long long
value{_Number<10U, _Digs...>::value};
};
} // namespace __parse_int
namespace __select_int {
template<unsigned long long _Val, typename... _Ints>
struct _Select_int_base;
template<unsigned long long _Val, typename _IntType, typename... _Ints>
struct _Select_int_base<_Val, _IntType, _Ints...>
: integral_constant
<
typename conditional
<
_Val <= static_cast<unsigned long long>
(std::numeric_limits<_IntType>::max()),
_IntType,
typename _Select_int_base<_Val, _Ints...>::value_type
>::type,
_Val
>
{ };
template<unsigned long long _Val>
struct _Select_int_base<_Val> : integral_constant<unsigned long long, _Val>
{ };
template<char... _Digs>
struct _Select_int
: _Select_int_base<
__parse_int::_Parse_int<_Digs...>::value,
unsigned char,
unsigned short,
unsigned int,
unsigned long,
unsigned long long
>
{ };
} // namespace __select_int
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // __cplusplus > 201103L
#endif // _PARSE_NUMBERS_H