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1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___RANDOM_CLAMP_TO_INTEGRAL_H10#define _LIBCPP___RANDOM_CLAMP_TO_INTEGRAL_H11 12#include <__config>13#include <cmath>14#include <limits>15 16#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)17# pragma GCC system_header18#endif19 20_LIBCPP_PUSH_MACROS21#include <__undef_macros>22 23_LIBCPP_BEGIN_NAMESPACE_STD24 25template <class _IntT,26 class _FloatT,27 bool _FloatBigger = (numeric_limits<_FloatT>::digits > numeric_limits<_IntT>::digits),28 int _Bits = (numeric_limits<_IntT>::digits - numeric_limits<_FloatT>::digits)>29_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _IntT __max_representable_int_for_float() _NOEXCEPT {30 static_assert(is_floating_point<_FloatT>::value, "must be a floating point type");31 static_assert(is_integral<_IntT>::value, "must be an integral type");32 static_assert(numeric_limits<_FloatT>::radix == 2, "FloatT has incorrect radix");33 static_assert(34 (_IsSame<_FloatT, float>::value || _IsSame<_FloatT, double>::value || _IsSame<_FloatT, long double>::value),35 "unsupported floating point type");36 return _FloatBigger ? numeric_limits<_IntT>::max() : (numeric_limits<_IntT>::max() >> _Bits << _Bits);37}38 39// Convert a floating point number to the specified integral type after40// clamping to the integral type's representable range.41//42// The behavior is undefined if `__r` is NaN.43template <class _IntT, class _RealT>44_LIBCPP_HIDE_FROM_ABI _IntT __clamp_to_integral(_RealT __r) _NOEXCEPT {45 using _Lim = numeric_limits<_IntT>;46 const _IntT __max_val = std::__max_representable_int_for_float<_IntT, _RealT>();47 if (__r >= ::nextafter(static_cast<_RealT>(__max_val), INFINITY)) {48 return _Lim::max();49 } else if (__r <= _Lim::lowest()) {50 return _Lim::min();51 }52 return static_cast<_IntT>(__r);53}54 55_LIBCPP_END_NAMESPACE_STD56 57_LIBCPP_POP_MACROS58 59#endif // _LIBCPP___RANDOM_CLAMP_TO_INTEGRAL_H60