| 1 | // Copyright (C) 2023 The Qt Company Ltd. |
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| 2 | // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only |
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| 3 | |
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| 4 | #ifndef QAUDIOSTATEMACHINEUTILS_P_H |
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| 5 | #define QAUDIOSTATEMACHINEUTILS_P_H |
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| 6 | |
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| 7 | // |
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| 8 | // W A R N I N G |
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| 9 | // ------------- |
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| 10 | // |
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| 11 | // This file is not part of the Qt API. It exists purely as an |
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| 12 | // implementation detail. This header file may change from version to |
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| 13 | // version without notice, or even be removed. |
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| 14 | // |
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| 15 | // We mean it. |
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| 16 | // |
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| 17 | |
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| 18 | #include "qaudio.h" |
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| 19 | |
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| 20 | QT_BEGIN_NAMESPACE |
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| 21 | |
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| 22 | namespace AudioStateMachineUtils { |
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| 23 | |
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| 24 | using RawState = int; |
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| 25 | |
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| 26 | constexpr uint32_t AudioStateBitsCount = 8; |
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| 27 | constexpr RawState AudioStateMask = 0xFF; |
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| 28 | constexpr RawState AudioErrorMask = 0xFF00; |
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| 29 | constexpr RawState DrainingFlag = 0x10000; |
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| 30 | |
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| 31 | static_assert(!(AudioStateMask & DrainingFlag) && !(AudioStateMask & AudioErrorMask) |
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| 32 | && !(AudioErrorMask & DrainingFlag), |
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| 33 | "Invalid masks" ); |
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| 34 | |
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| 35 | constexpr bool isDrainingState(RawState state) |
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| 36 | { |
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| 37 | return (state & DrainingFlag) != 0; |
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| 38 | } |
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| 39 | |
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| 40 | constexpr RawState addDrainingFlag(RawState state) |
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| 41 | { |
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| 42 | return state | DrainingFlag; |
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| 43 | } |
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| 44 | |
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| 45 | constexpr RawState removeDrainingFlag(RawState state) |
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| 46 | { |
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| 47 | return state & ~DrainingFlag; |
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| 48 | } |
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| 49 | |
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| 50 | constexpr QAudio::State toAudioState(RawState state) |
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| 51 | { |
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| 52 | return QAudio::State(state & AudioStateMask); |
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| 53 | } |
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| 54 | |
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| 55 | constexpr QAudio::Error toAudioError(RawState state) |
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| 56 | { |
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| 57 | return QAudio::Error((state & AudioErrorMask) >> AudioStateBitsCount); |
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| 58 | } |
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| 59 | |
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| 60 | constexpr RawState toRawState(QAudio::State state, QAudio::Error error = QAudio::NoError) |
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| 61 | { |
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| 62 | return state | (error << AudioStateBitsCount); |
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| 63 | } |
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| 64 | |
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| 65 | constexpr RawState setStateError(RawState state, QAudio::Error error) |
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| 66 | { |
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| 67 | return (error << AudioStateBitsCount) | (state & ~AudioErrorMask); |
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| 68 | } |
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| 69 | |
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| 70 | template <typename... States> |
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| 71 | constexpr auto makeStatesChecker(States... states) |
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| 72 | { |
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| 73 | return [=](RawState state) { |
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| 74 | state &= (AudioStateMask | DrainingFlag); |
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| 75 | return (... || (state == states)); |
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| 76 | }; |
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| 77 | } |
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| 78 | |
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| 79 | // ensures compareExchange (testAndSet) operation with opportunity |
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| 80 | // to check several states, can be considered as atomic |
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| 81 | template <typename T, typename Predicate, typename NewValueGetter> |
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| 82 | bool multipleCompareExchange(std::atomic<T> &target, T &prevValue, Predicate predicate, |
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| 83 | NewValueGetter newValueGetter) |
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| 84 | { |
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| 85 | while (predicate(prevValue)) |
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| 86 | if (target.compare_exchange_strong(prevValue, newValueGetter(prevValue), |
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| 87 | std::memory_order_acq_rel)) |
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| 88 | return true; |
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| 89 | |
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| 90 | return false; |
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| 91 | } |
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| 92 | } // namespace AudioStateMachineUtils |
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| 93 | |
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| 94 | QT_END_NAMESPACE |
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| 95 | |
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| 96 | #endif // QAUDIOSTATEMACHINEUTILS_P_H |
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| 97 | |
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