62 lines
1.4 KiB
C++
62 lines
1.4 KiB
C++
#include "countdown.h"
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Countdown::Countdown(qint64 durationMs)
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: m_duration(qMax<qint64>(0, durationMs)), m_remainingAtStart(m_duration)
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{
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}
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bool Countdown::setDuration(qint64 durationMs)
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{
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if (m_state == State::Running || m_state == State::Paused || durationMs < 0)
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return false;
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m_duration = durationMs;
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reset();
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return true;
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}
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void Countdown::start(qint64 nowMs)
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{
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if (m_state == State::Running || m_duration <= 0)
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return;
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if (m_state != State::Paused)
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m_remainingAtStart = m_duration;
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m_segmentStarted = nowMs;
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m_state = State::Running;
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}
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qint64 Countdown::remaining(qint64 nowMs) const
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{
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if (m_state == State::Finished)
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return 0;
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if (m_state != State::Running)
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return m_remainingAtStart;
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const qint64 elapsed = qMax<qint64>(0, nowMs - m_segmentStarted);
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return qMax<qint64>(0, m_remainingAtStart - elapsed);
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}
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void Countdown::update(qint64 nowMs)
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{
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if (m_state == State::Running && remaining(nowMs) == 0) {
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m_remainingAtStart = 0;
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m_state = State::Finished;
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}
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}
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void Countdown::pause(qint64 nowMs)
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{
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update(nowMs);
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if (m_state != State::Running)
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return;
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// 先保存这一刻的剩余时间，再切换状态，暂停期间不继续扣减。
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m_remainingAtStart = remaining(nowMs);
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m_state = State::Paused;
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}
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void Countdown::reset()
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{
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m_remainingAtStart = m_duration;
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m_segmentStarted = 0;
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m_state = State::Ready;
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}
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