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-exception 6// 7//===----------------------------------------------------------------------===// 8 9#include <algorithm> 10#include <random> 11 12#ifndef _LIBCPP_HAS_NO_THREADS 13# include <mutex> 14# if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB) 15# pragma comment(lib, "pthread") 16# endif 17#endif 18 19_LIBCPP_BEGIN_NAMESPACE_STD 20 21#ifndef _LIBCPP_HAS_NO_THREADS 22static constinit __libcpp_mutex_t __rs_mut = _LIBCPP_MUTEX_INITIALIZER; 23#endif 24unsigned __rs_default::__c_ = 0; 25 26__rs_default::__rs_default() { 27#ifndef _LIBCPP_HAS_NO_THREADS 28 __libcpp_mutex_lock(&__rs_mut); 29#endif 30 __c_ = 1; 31} 32 33__rs_default::__rs_default(const __rs_default&) { ++__c_; } 34 35__rs_default::~__rs_default() { 36#ifndef _LIBCPP_HAS_NO_THREADS 37 if (--__c_ == 0) 38 __libcpp_mutex_unlock(&__rs_mut); 39#else 40 --__c_; 41#endif 42} 43 44__rs_default::result_type __rs_default::operator()() { 45 static mt19937 __rs_g; 46 return __rs_g(); 47} 48 49__rs_default __rs_get() { return __rs_default(); } 50 51_LIBCPP_END_NAMESPACE_STD 52