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https://github.com/llvm-mirror/libcxx.git
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018a3d51a4
Summary: This patch improves how libc++ handles min/max macros within the headers. Previously libc++ would undef them and emit a warning. This patch changes libc++ to use `#pragma push_macro` to save the macro before undefining it, and `#pragma pop_macro` to restore the macros and the end of the header. Reviewers: mclow.lists, bcraig, compnerd, EricWF Reviewed By: EricWF Subscribers: cfe-commits, krytarowski Differential Revision: https://reviews.llvm.org/D33080 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@304357 91177308-0d34-0410-b5e6-96231b3b80d8
120 lines
3.6 KiB
C++
120 lines
3.6 KiB
C++
// -*- C++ -*-
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//===--------------------------- numeric ----------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP_EXPERIMENTAL_NUMERIC
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#define _LIBCPP_EXPERIMENTAL_NUMERIC
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/*
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experimental/numeric synopsis
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// C++1z
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namespace std {
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namespace experimental {
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inline namespace fundamentals_v2 {
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// 13.1.2, Greatest common divisor
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template<class M, class N>
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constexpr common_type_t<M,N> gcd(M m, N n);
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// 13.1.3, Least common multiple
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template<class M, class N>
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constexpr common_type_t<M,N> lcm(M m, N n);
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} // namespace fundamentals_v2
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} // namespace experimental
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} // namespace std
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*/
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#include <experimental/__config>
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#include <numeric>
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#include <type_traits> // is_integral
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#include <limits> // numeric_limits
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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#pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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#if _LIBCPP_STD_VER > 11
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_LIBCPP_BEGIN_NAMESPACE_LFTS_V2
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template <typename _Result, typename _Source, bool _IsSigned = is_signed<_Source>::value> struct __abs;
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template <typename _Result, typename _Source>
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struct __abs<_Result, _Source, true> {
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_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
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_Result operator()(_Source __t) const noexcept
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{
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if (__t >= 0) return __t;
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if (__t == numeric_limits<_Source>::min()) return -static_cast<_Result>(__t);
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return -__t;
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}
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};
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template <typename _Result, typename _Source>
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struct __abs<_Result, _Source, false> {
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_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
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_Result operator()(_Source __t) const noexcept { return __t; }
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};
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template<class _Tp>
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_LIBCPP_CONSTEXPR _LIBCPP_HIDDEN
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inline _Tp __gcd(_Tp __m, _Tp __n)
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{
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static_assert((!is_signed<_Tp>::value), "" );
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return __n == 0 ? __m : _VSTD_LFTS_V2::__gcd<_Tp>(__n, __m % __n);
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}
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template<class _Tp, class _Up>
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_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
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common_type_t<_Tp,_Up>
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gcd(_Tp __m, _Up __n)
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{
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static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to gcd must be integer types");
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static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to gcd cannot be bool" );
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static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to gcd cannot be bool" );
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using _Rp = common_type_t<_Tp,_Up>;
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using _Wp = make_unsigned_t<_Rp>;
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return static_cast<_Rp>(_VSTD_LFTS_V2::__gcd(
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static_cast<_Wp>(__abs<_Rp, _Tp>()(__m)),
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static_cast<_Wp>(__abs<_Rp, _Up>()(__n))));
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}
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template<class _Tp, class _Up>
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_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
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common_type_t<_Tp,_Up>
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lcm(_Tp __m, _Up __n)
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{
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static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to lcm must be integer types");
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static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to lcm cannot be bool" );
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static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to lcm cannot be bool" );
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if (__m == 0 || __n == 0)
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return 0;
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using _Rp = common_type_t<_Tp,_Up>;
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_Rp __val1 = __abs<_Rp, _Tp>()(__m) / _VSTD_LFTS_V2::gcd(__m, __n);
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_Rp __val2 = __abs<_Rp, _Up>()(__n);
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_LIBCPP_ASSERT((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow in lcm");
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return __val1 * __val2;
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}
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_LIBCPP_END_NAMESPACE_LFTS_V2
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#endif /* _LIBCPP_STD_VER > 11 */
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_LIBCPP_POP_MACROS
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#endif /* _LIBCPP_EXPERIMENTAL_NUMERIC */
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