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