1*4824e7fdSDimitry Andric //===----------------------------------------------------------------------===// 2*4824e7fdSDimitry Andric // 3*4824e7fdSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*4824e7fdSDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*4824e7fdSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*4824e7fdSDimitry Andric // 7*4824e7fdSDimitry Andric //===----------------------------------------------------------------------===// 8*4824e7fdSDimitry Andric 9*4824e7fdSDimitry Andric #ifndef _LIBCPP___RANDOM_GENERATE_CANONICAL_H 10*4824e7fdSDimitry Andric #define _LIBCPP___RANDOM_GENERATE_CANONICAL_H 11*4824e7fdSDimitry Andric 12*4824e7fdSDimitry Andric #include <__config> 13*4824e7fdSDimitry Andric #include <__random/log2.h> 14*4824e7fdSDimitry Andric #include <cstdint> 15*4824e7fdSDimitry Andric #include <initializer_list> 16*4824e7fdSDimitry Andric #include <limits> 17*4824e7fdSDimitry Andric 18*4824e7fdSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 19*4824e7fdSDimitry Andric #pragma GCC system_header 20*4824e7fdSDimitry Andric #endif 21*4824e7fdSDimitry Andric 22*4824e7fdSDimitry Andric _LIBCPP_PUSH_MACROS 23*4824e7fdSDimitry Andric #include <__undef_macros> 24*4824e7fdSDimitry Andric 25*4824e7fdSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 26*4824e7fdSDimitry Andric 27*4824e7fdSDimitry Andric // generate_canonical 28*4824e7fdSDimitry Andric 29*4824e7fdSDimitry Andric template<class _RealType, size_t __bits, class _URNG> 30*4824e7fdSDimitry Andric _RealType 31*4824e7fdSDimitry Andric generate_canonical(_URNG& __g) 32*4824e7fdSDimitry Andric { 33*4824e7fdSDimitry Andric const size_t _Dt = numeric_limits<_RealType>::digits; 34*4824e7fdSDimitry Andric const size_t __b = _Dt < __bits ? _Dt : __bits; 35*4824e7fdSDimitry Andric #ifdef _LIBCPP_CXX03_LANG 36*4824e7fdSDimitry Andric const size_t __logR = __log2<uint64_t, _URNG::_Max - _URNG::_Min + uint64_t(1)>::value; 37*4824e7fdSDimitry Andric #else 38*4824e7fdSDimitry Andric const size_t __logR = __log2<uint64_t, _URNG::max() - _URNG::min() + uint64_t(1)>::value; 39*4824e7fdSDimitry Andric #endif 40*4824e7fdSDimitry Andric const size_t __k = __b / __logR + (__b % __logR != 0) + (__b == 0); 41*4824e7fdSDimitry Andric const _RealType _Rp = static_cast<_RealType>(_URNG::max() - _URNG::min()) + _RealType(1); 42*4824e7fdSDimitry Andric _RealType __base = _Rp; 43*4824e7fdSDimitry Andric _RealType _Sp = __g() - _URNG::min(); 44*4824e7fdSDimitry Andric for (size_t __i = 1; __i < __k; ++__i, __base *= _Rp) 45*4824e7fdSDimitry Andric _Sp += (__g() - _URNG::min()) * __base; 46*4824e7fdSDimitry Andric return _Sp / __base; 47*4824e7fdSDimitry Andric } 48*4824e7fdSDimitry Andric 49*4824e7fdSDimitry Andric _LIBCPP_END_NAMESPACE_STD 50*4824e7fdSDimitry Andric 51*4824e7fdSDimitry Andric _LIBCPP_POP_MACROS 52*4824e7fdSDimitry Andric 53*4824e7fdSDimitry Andric #endif // _LIBCPP___RANDOM_GENERATE_CANONICAL_H 54