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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___RANDOM_CLAMP_TO_INTEGRAL_H
#define _LIBCPP___RANDOM_CLAMP_TO_INTEGRAL_H
#include <__config>
#include <cmath>
#include <limits>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _IntT, class _FloatT,
bool _FloatBigger = (numeric_limits<_FloatT>::digits > numeric_limits<_IntT>::digits),
int _Bits = (numeric_limits<_IntT>::digits - numeric_limits<_FloatT>::digits)>
_LIBCPP_INLINE_VISIBILITY
_LIBCPP_CONSTEXPR _IntT __max_representable_int_for_float() _NOEXCEPT {
static_assert(is_floating_point<_FloatT>::value, "must be a floating point type");
static_assert(is_integral<_IntT>::value, "must be an integral type");
static_assert(numeric_limits<_FloatT>::radix == 2, "FloatT has incorrect radix");
static_assert((_IsSame<_FloatT, float>::value || _IsSame<_FloatT, double>::value
|| _IsSame<_FloatT,long double>::value), "unsupported floating point type");
return _FloatBigger ? numeric_limits<_IntT>::max() : (numeric_limits<_IntT>::max() >> _Bits << _Bits);
}
// Convert a floating point number to the specified integral type after
// clamping to the integral type's representable range.
//
// The behavior is undefined if `__r` is NaN.
template <class _IntT, class _RealT>
_LIBCPP_INLINE_VISIBILITY
_IntT __clamp_to_integral(_RealT __r) _NOEXCEPT {
using _Lim = numeric_limits<_IntT>;
const _IntT _MaxVal = __max_representable_int_for_float<_IntT, _RealT>();
if (__r >= ::nextafter(static_cast<_RealT>(_MaxVal), INFINITY)) {
return _Lim::max();
} else if (__r <= _Lim::lowest()) {
return _Lim::min();
}
return static_cast<_IntT>(__r);
}
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___RANDOM_CLAMP_TO_INTEGRAL_H
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