95 lines
1.9 KiB
C++
95 lines
1.9 KiB
C++
#include <psemek/audio/effect/pause.hpp>
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#include <psemek/audio/detail/smooth.hpp>
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#include <atomic>
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namespace psemek::audio
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{
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namespace
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{
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struct pause_control_impl
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: pause_control
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{
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pause_control_impl(stream_ptr stream, bool paused, duration length)
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: stream_(std::move(stream))
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, paused_{paused}
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, length_(length)
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, level_(paused ? 0 : length_.samples())
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{}
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bool paused() const override
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{
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return paused_.load();
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}
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bool paused(bool value) override
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{
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return paused_.exchange(value);
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}
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std::optional<std::size_t> length() const override
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{
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return stream_->length();
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}
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std::size_t read(util::span<float> samples) override
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{
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bool const paused = paused_.load();
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if (paused)
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{
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auto count = stream_->read(samples.prefix(std::min(samples.size(), level_)));
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for (std::size_t i = 0; i < count; i += 2)
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{
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float gain = static_cast<float>(level_) / length_.samples();
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samples[i + 0] *= gain;
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samples[i + 1] *= gain;
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level_ -= 2;
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}
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std::fill(samples.begin() + count, samples.end(), 0.f);
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return samples.size();
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}
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else
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{
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auto count = stream_->read(samples);
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auto const max_level = static_cast<std::size_t>(length_.samples());
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for (std::size_t i = 0; i < count; i += 2)
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{
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float gain = static_cast<float>(level_) / max_level;
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samples[i + 0] *= gain;
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samples[i + 1] *= gain;
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if (level_ < max_level)
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level_ += 2;
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}
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return count;
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}
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}
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std::size_t played() const override
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{
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return stream_->played();
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}
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private:
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stream_ptr stream_;
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std::atomic<bool> paused_;
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duration length_;
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std::size_t level_;
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};
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}
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std::shared_ptr<pause_control> pause(stream_ptr stream, bool paused, duration length)
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{
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return std::make_shared<pause_control_impl>(std::move(stream), paused, length);
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}
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}
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