1e78f53d1SNikolas Klauser //===----------------------------------------------------------------------===// 2e78f53d1SNikolas Klauser // 3e78f53d1SNikolas Klauser // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4e78f53d1SNikolas Klauser // See https://llvm.org/LICENSE.txt for license information. 5e78f53d1SNikolas Klauser // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6e78f53d1SNikolas Klauser // 7e78f53d1SNikolas Klauser //===----------------------------------------------------------------------===// 8e78f53d1SNikolas Klauser 9*ce777190SNikolas Klauser #ifndef _LIBCPP___CXX03___RANDOM_GENERATE_CANONICAL_H 10*ce777190SNikolas Klauser #define _LIBCPP___CXX03___RANDOM_GENERATE_CANONICAL_H 11e78f53d1SNikolas Klauser 1273fbae83SNikolas Klauser #include <__cxx03/__config> 1373fbae83SNikolas Klauser #include <__cxx03/__random/log2.h> 1473fbae83SNikolas Klauser #include <__cxx03/cstdint> 1573fbae83SNikolas Klauser #include <__cxx03/initializer_list> 1673fbae83SNikolas Klauser #include <__cxx03/limits> 17e78f53d1SNikolas Klauser 18e78f53d1SNikolas Klauser #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 19e78f53d1SNikolas Klauser # pragma GCC system_header 20e78f53d1SNikolas Klauser #endif 21e78f53d1SNikolas Klauser 22e78f53d1SNikolas Klauser _LIBCPP_PUSH_MACROS 2373fbae83SNikolas Klauser #include <__cxx03/__undef_macros> 24e78f53d1SNikolas Klauser 25e78f53d1SNikolas Klauser _LIBCPP_BEGIN_NAMESPACE_STD 26e78f53d1SNikolas Klauser 27e78f53d1SNikolas Klauser // generate_canonical 28e78f53d1SNikolas Klauser 29e78f53d1SNikolas Klauser template <class _RealType, size_t __bits, class _URNG> 30e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI _RealType generate_canonical(_URNG& __g) { 31e78f53d1SNikolas Klauser const size_t __dt = numeric_limits<_RealType>::digits; 32e78f53d1SNikolas Klauser const size_t __b = __dt < __bits ? __dt : __bits; 33e78f53d1SNikolas Klauser #ifdef _LIBCPP_CXX03_LANG 34e78f53d1SNikolas Klauser const size_t __log_r = __log2<uint64_t, _URNG::_Max - _URNG::_Min + uint64_t(1)>::value; 35e78f53d1SNikolas Klauser #else 36e78f53d1SNikolas Klauser const size_t __log_r = __log2<uint64_t, _URNG::max() - _URNG::min() + uint64_t(1)>::value; 37e78f53d1SNikolas Klauser #endif 38e78f53d1SNikolas Klauser const size_t __k = __b / __log_r + (__b % __log_r != 0) + (__b == 0); 39e78f53d1SNikolas Klauser const _RealType __rp = static_cast<_RealType>(_URNG::max() - _URNG::min()) + _RealType(1); 40e78f53d1SNikolas Klauser _RealType __base = __rp; 41e78f53d1SNikolas Klauser _RealType __sp = __g() - _URNG::min(); 42e78f53d1SNikolas Klauser for (size_t __i = 1; __i < __k; ++__i, __base *= __rp) 43e78f53d1SNikolas Klauser __sp += (__g() - _URNG::min()) * __base; 44e78f53d1SNikolas Klauser return __sp / __base; 45e78f53d1SNikolas Klauser } 46e78f53d1SNikolas Klauser 47e78f53d1SNikolas Klauser _LIBCPP_END_NAMESPACE_STD 48e78f53d1SNikolas Klauser 49e78f53d1SNikolas Klauser _LIBCPP_POP_MACROS 50e78f53d1SNikolas Klauser 51*ce777190SNikolas Klauser #endif // _LIBCPP___CXX03___RANDOM_GENERATE_CANONICAL_H 52