/* * Copyright (c) 2018-2020 Atmosphère-NX * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include <stratosphere.hpp> #include "impl/os_random_impl.hpp" namespace ams::os { namespace { util::TinyMT g_random; os::Mutex g_random_mutex; bool g_initialized_random; template<typename T> inline T GenerateRandomTImpl(T max) { static_assert(std::is_integral<T>::value && std::is_unsigned<T>::value); const T EffectiveMax = (std::numeric_limits<T>::max() / max) * max; T cur_rnd; while (true) { os::GenerateRandomBytes(&cur_rnd, sizeof(T)); if (cur_rnd < EffectiveMax) { return cur_rnd % max; } } } } void GenerateRandomBytes(void *dst, size_t size) { std::scoped_lock lk(g_random_mutex); if (!g_initialized_random) { impl::InitializeRandomImpl(&g_random); g_initialized_random = true; } g_random.GenerateRandomBytes(dst, size); } u32 GenerateRandomU32(u32 max) { return GenerateRandomTImpl<u32>(max); } u64 GenerateRandomU64(u64 max) { return GenerateRandomTImpl<u64>(max); } }