Refactor SampleBuffer to use value semantics

include/AudioSampleRecorder.h

@@ -45,7 +45,7 @@ class AudioSampleRecorder : public AudioDevice
 	~AudioSampleRecorder() override;
 
 	f_cnt_t framesRecorded() const;
-	std::shared_ptr<const SampleBuffer> createSampleBuffer();
+	SampleBuffer createSampleBuffer();
 
 private:
 	void writeBuffer(const SampleFrame* _ab, const fpp_t _frames) override;

include/EnvelopeAndLfoParameters.h

@@ -25,8 +25,6 @@
 #ifndef LMMS_ENVELOPE_AND_LFO_PARAMETERS_H
 #define LMMS_ENVELOPE_AND_LFO_PARAMETERS_H
 
-#include <memory>
-
 #include "JournallingObject.h"
 #include "AutomatableModel.h"
 #include "SampleBuffer.h"
@@ -145,7 +143,7 @@ class LMMS_EXPORT EnvelopeAndLfoParameters : public Model, public JournallingObj
 	const TempoSyncKnobModel& getLfoSpeedModel() const { return m_lfoSpeedModel; }
 	const BoolModel& getX100Model() const { return m_x100Model; }
 	const IntModel& getLfoWaveModel() const { return m_lfoWaveModel; }
-	std::shared_ptr<const SampleBuffer> getLfoUserWave() const { return m_userWave; }
+	const SampleBuffer& getLfoUserWave() const { return m_userWave; }
 
 public slots:
 	void updateSampleVars();
@@ -200,7 +198,7 @@ public slots:
 	sample_t * m_lfoShapeData;
 	sample_t m_random;
 	bool m_bad_lfoShapeData;
-	std::shared_ptr<const SampleBuffer> m_userWave = SampleBuffer::emptyBuffer();
+	SampleBuffer m_userWave;
 
 	constexpr static auto NumLfoShapes = static_cast<std::size_t>(LfoShape::Count);
 

include/LfoController.h

@@ -84,7 +84,7 @@ public slots:
 
 private:
 	float m_heldSample;
-	std::shared_ptr<const SampleBuffer> m_userDefSampleBuffer = SampleBuffer::emptyBuffer();
+	SampleBuffer m_userDefSampleBuffer;
 
 protected slots:
 	void updatePhase();

include/Oscillator.h

@@ -98,7 +98,7 @@ class LMMS_EXPORT Oscillator
 		m_useWaveTable = n;
 	}
 
-	void setUserWave(std::shared_ptr<const SampleBuffer> _wave)
+	void setUserWave(const SampleBuffer* _wave)
 	{
 		m_userWave = _wave;
 	}
@@ -167,8 +167,8 @@ class LMMS_EXPORT Oscillator
 
 	static sample_t userWaveSample(const SampleBuffer* buffer, const float sample)
 	{
-		if (buffer == nullptr || buffer->size() == 0) { return 0; }
-		const auto frames = buffer->size();
+		if (buffer == nullptr || buffer->frames() == 0) { return 0; }
+		const auto frames = buffer->frames();
 		const auto frame = absFraction(sample) * frames;
 		const auto f1 = static_cast<f_cnt_t>(frame);
 
@@ -250,7 +250,7 @@ class LMMS_EXPORT Oscillator
 	Oscillator * m_subOsc;
 	float m_phaseOffset;
 	float m_phase;
-	std::shared_ptr<const SampleBuffer> m_userWave = SampleBuffer::emptyBuffer();
+	const SampleBuffer* m_userWave;
 	std::shared_ptr<const OscillatorConstants::waveform_t> m_userAntiAliasWaveTable;
 	bool m_useWaveTable;
 	// There are many update*() variants; the modulator flag is stored as a member variable to avoid

include/Sample.h

@@ -25,8 +25,8 @@
 #ifndef LMMS_SAMPLE_H
 #define LMMS_SAMPLE_H
 
-#include <memory>
 
+#include "AudioEngine.h"
 #include "AudioResampler.h"
 #include "Note.h"
 #include "SampleBuffer.h"
@@ -68,11 +68,9 @@ class LMMS_EXPORT Sample
 	};
 
 	Sample() = default;
-
-	Sample(const SampleFrame* data, size_t numFrames, int sampleRate = Engine::audioEngine()->outputSampleRate());
 	Sample(const Sample& other);
 	Sample(Sample&& other) noexcept;
-	explicit Sample(std::shared_ptr<const SampleBuffer> buffer);
+	explicit Sample(SampleBuffer buffer);
 
 	auto operator=(const Sample&) -> Sample&;
 	auto operator=(Sample&&) noexcept -> Sample&;
@@ -81,14 +79,14 @@ class LMMS_EXPORT Sample
 		double ratio = 1.0) const -> bool;
 
 	auto sampleDuration() const -> std::chrono::milliseconds;
-	auto sampleFile() const -> const QString& { return m_buffer->audioFile(); }
-	auto sampleRate() const -> int { return m_buffer->sampleRate(); }
-	auto sampleSize() const -> size_t { return m_buffer->size(); }
+	auto sampleFile() const -> const QString& { return m_buffer.path(); }
+	auto sampleRate() const -> int { return m_buffer.sampleRate(); }
+	auto sampleSize() const -> size_t { return m_buffer.frames(); }
 
-	auto toBase64() const -> QString { return m_buffer->toBase64(); }
+	auto toBase64() const -> QString { return m_buffer.toBase64(); }
 
-	auto data() const -> const SampleFrame* { return m_buffer->data(); }
-	auto buffer() const -> std::shared_ptr<const SampleBuffer> { return m_buffer; }
+	auto data() const -> const SampleFrame* { return m_buffer.data(); }
+	auto buffer() const -> const SampleBuffer& { return m_buffer; }
 	auto startFrame() const -> int { return m_startFrame.load(std::memory_order_relaxed); }
 	auto endFrame() const -> int { return m_endFrame.load(std::memory_order_relaxed); }
 	auto loopStartFrame() const -> int { return m_loopStartFrame.load(std::memory_order_relaxed); }
@@ -108,7 +106,7 @@ class LMMS_EXPORT Sample
 
 private:
 	f_cnt_t render(SampleFrame* dst, f_cnt_t size, PlaybackState* state, Loop loop) const;
-	std::shared_ptr<const SampleBuffer> m_buffer = SampleBuffer::emptyBuffer();
+	SampleBuffer m_buffer;
 	std::atomic<int> m_startFrame = 0;
 	std::atomic<int> m_endFrame = 0;
 	std::atomic<int> m_loopStartFrame = 0;

include/SampleBuffer.h

@@ -27,70 +27,87 @@
 
 #include <QString>
 #include <memory>
+#include <optional>
 #include <vector>
 
-#include "AudioEngine.h"
-#include "Engine.h"
 #include "LmmsTypes.h"
+#include "SampleFrame.h"
 #include "lmms_export.h"
 
 namespace lmms {
+/**
+ * @class SampleBuffer
+ *
+ * @brief A thread-safe, reference-counted container of immutable PCM audio data.
+ *
+ * SampleBuffer is designed for playback of audio files or Base64 assets possibly across multiple threads.
+ * It enforces shared ownership: copying a SampleBuffer increments a ref count for the shared audio data rather than
+ * deep copying it.
+ *
+ * @warning This class is immutable. If you need a buffer for real-time
+ * effect processing or mixing, use @ref AudioBuffer instead.
+ *
+ * @note Populated via static factory methods @ref fromFile() and @ref fromBase64().
+ */
 class LMMS_EXPORT SampleBuffer
 {
 public:
-	using value_type = SampleFrame;
-	using reference = SampleFrame&;
-	using const_reference = const SampleFrame&;
-	using iterator = std::vector<SampleFrame>::iterator;
-	using const_iterator = std::vector<SampleFrame>::const_iterator;
-	using difference_type = std::vector<SampleFrame>::difference_type;
-	using size_type = std::vector<SampleFrame>::size_type;
-	using reverse_iterator = std::vector<SampleFrame>::reverse_iterator;
-	using const_reverse_iterator = std::vector<SampleFrame>::const_reverse_iterator;
-
+	/** @brief Creates an empty SampleBuffer. */
 	SampleBuffer() = default;
-	SampleBuffer(std::vector<SampleFrame> data, int sampleRate, const QString& audioFile = "");
-	SampleBuffer(
-		const SampleFrame* data, size_t numFrames, int sampleRate = Engine::audioEngine()->outputSampleRate());
 
-	friend void swap(SampleBuffer& first, SampleBuffer& second) noexcept;
-	auto toBase64() const -> QString;
-
-	auto audioFile() const -> const QString& { return m_audioFile; }
-	auto sampleRate() const -> sample_rate_t { return m_sampleRate; }
+	/**
+	 * @brief Constructs a buffer with explicit data.
+	 * @param data A vector of SampleFrame containing the audio data.
+	 * @param sampleRate The recording rate of the source (e.g., 44100).
+	 * @param path The filesystem path the data originated from.
+	 */
+	SampleBuffer(std::vector<SampleFrame> data, sample_rate_t sampleRate, const QString& path = "");
 
-	auto begin() -> iterator { return m_data.begin(); }
-	auto end() -> iterator { return m_data.end(); }
+	/** @returns a const reference to the audio frame at the given frame index. */
+	auto operator[](f_cnt_t index) const -> const SampleFrame& { return m_data[index]; }
 
-	auto begin() const -> const_iterator { return m_data.begin(); }
-	auto end() const -> const_iterator { return m_data.end(); }
-
-	auto cbegin() const -> const_iterator { return m_data.cbegin(); }
-	auto cend() const -> const_iterator { return m_data.cend(); }
+	/** @brief Serializes the raw PCM data into a Base64 string for project saving.
+		@todo This function should be removed once Base64 is migrated to audio files on disk.
+	 */
+	auto toBase64() const -> QString;
 
-	auto rbegin() -> reverse_iterator { return m_data.rbegin(); }
-	auto rend() -> reverse_iterator { return m_data.rend(); }
+	/** @returns true if the buffer contains no audio data. */
+	auto empty() const -> bool { return m_frames == 0; }
 
-	auto rbegin() const -> const_reverse_iterator { return m_data.rbegin(); }
-	auto rend() const -> const_reverse_iterator { return m_data.rend(); }
+	/** @returns direct access to the raw audio data. */
+	auto data() const -> const SampleFrame* { return m_data.get(); }
 
-	auto crbegin() const -> const_reverse_iterator { return m_data.crbegin(); }
-	auto crend() const -> const_reverse_iterator { return m_data.crend(); }
+	/** @returns the file path associated with this buffer, if any. */
+	auto path() const -> const QString& { return m_path; }
 
-	auto data() const -> const SampleFrame* { return m_data.data(); }
-	auto size() const -> size_type { return m_data.size(); }
-	auto empty() const -> bool { return m_data.empty(); }
+	/** @returns the total number of audio frames. */
+	auto frames() const -> f_cnt_t { return m_frames; }
 
-	static auto emptyBuffer() -> std::shared_ptr<const SampleBuffer>;
+	/** @returns the original sample rate of the data. */
+	auto sampleRate() const -> sample_rate_t { return m_sampleRate; }
 
-	static std::shared_ptr<const SampleBuffer> fromFile(const QString& path);
-	static std::shared_ptr<const SampleBuffer> fromBase64(
-		const QString& str, int sampleRate = Engine::audioEngine()->outputSampleRate());
+	/**
+	 * @brief Factory method to load and decode an audio file into a SampleBuffer.
+	 * @param path The absolute path to the audio file (WAV, FLAC, OGG, etc.).
+	 * @return std::optional containing the buffer on success, or std::nullopt on failure.
+	 */
+	static std::optional<SampleBuffer> fromFile(const QString& path);
+
+	/**
+	 * @brief Factory method to reconstruct a buffer from a Base64 string.
+	 * @param str The Base64 encoded audio data.
+	 * @param sampleRate The rate at which the encoded data should be interpreted.
+	 * @return std::optional containing the buffer on success.
+	 * @todo This function should be removed once Base64 is migrated to audio files on disk.
+	 */
+	static std::optional<SampleBuffer> fromBase64(const QString& str, sample_rate_t sampleRate);
 
 private:
-	std::vector<SampleFrame> m_data;
-	QString m_audioFile;
-	sample_rate_t m_sampleRate = Engine::audioEngine()->outputSampleRate();
+	f_cnt_t m_frames = 0;
+	sample_rate_t m_sampleRate = 0;
+	QString m_path;
+	inline static const auto emptyBuffer = std::make_shared<SampleFrame[]>(0);
+	std::shared_ptr<SampleFrame[]> m_data = emptyBuffer;
 };
 
 } // namespace lmms

include/SampleClip.h

@@ -77,7 +77,7 @@ class SampleClip : public Clip
 
 	bool isPlaying() const;
 	void setIsPlaying(bool isPlaying);
-	void setSampleBuffer(std::shared_ptr<const SampleBuffer> sb);
+	void setSampleBuffer(SampleBuffer buffer);
 
 	SampleClip* clone() override
 	{

include/SampleDecoder.h

@@ -39,7 +39,7 @@ class SampleDecoder
 	struct Result
 	{
 		std::vector<SampleFrame> data;
-		int sampleRate;
+		sample_rate_t sampleRate;
 	};
 
 	struct AudioType

include/SampleRecordHandle.h

@@ -54,7 +54,7 @@ class SampleRecordHandle : public PlayHandle
 	bool isFromTrack( const Track * _track ) const override;
 
 	f_cnt_t framesRecorded() const;
-	std::shared_ptr<const SampleBuffer> createSampleBuffer();
+	SampleBuffer createSampleBuffer();
 
 
 private:

include/SampleThumbnail.h

@@ -71,7 +71,7 @@ class LMMS_EXPORT SampleThumbnail
 	};
 
 	SampleThumbnail() = default;
-	SampleThumbnail(const Sample& sample);
+	SampleThumbnail(const SampleBuffer& buffer);
 	void visualize(VisualizeParameters parameters, QPainter& painter) const;
 
 private:
@@ -137,7 +137,7 @@ class LMMS_EXPORT SampleThumbnail
 
 	using ThumbnailCache = std::vector<Thumbnail>;
 	std::shared_ptr<ThumbnailCache> m_thumbnailCache = std::make_shared<ThumbnailCache>();
-	std::shared_ptr<const SampleBuffer> m_buffer = SampleBuffer::emptyBuffer();
+	SampleBuffer m_buffer;
 	inline static std::unordered_map<SampleThumbnailEntry, std::shared_ptr<ThumbnailCache>, Hash> s_sampleThumbnailCacheMap;
 };
 

plugins/AudioFileProcessor/AudioFileProcessor.cpp

@@ -224,7 +224,10 @@ void AudioFileProcessor::loadSettings(const QDomElement& elem)
 	}
 	else if (auto sampleData = elem.attribute("sampledata"); !sampleData.isEmpty())
 	{
-		m_sample = Sample(SampleBuffer::fromBase64(sampleData));
+		if (auto buffer = SampleBuffer::fromBase64(sampleData, Engine::audioEngine()->outputSampleRate()))
+		{
+			m_sample = Sample{std::move(buffer.value())};
+		}
 	}
 
 	m_loopModel.loadSettings(elem, "looped");
@@ -318,10 +321,13 @@ void AudioFileProcessor::setAudioFile(const QString& _audio_file, bool _rename)
 	}
 	// else we don't touch the track-name, because the user named it self
 
-	m_sample = Sample(SampleBuffer::fromFile(_audio_file));
-	loopPointChanged();
-	reverseModelChanged();
-	emit sampleUpdated();
+	if (auto buffer = SampleBuffer::fromFile(_audio_file))
+	{
+		m_sample = Sample(std::move(buffer.value()));
+		loopPointChanged();
+		reverseModelChanged();
+		emit sampleUpdated();
+	}
 }
 
 

plugins/Patman/Patman.cpp

@@ -342,7 +342,7 @@ PatmanInstrument::LoadError PatmanInstrument::loadPatch(
 			}
 		}
 
-		auto data = new SampleFrame[frames];
+		auto data = std::vector<SampleFrame>(frames);
 
 		for( f_cnt_t frame = 0; frame < frames; ++frame )
 		{
@@ -353,7 +353,7 @@ PatmanInstrument::LoadError PatmanInstrument::loadPatch(
 			}
 		}
 
-		auto psample = std::make_shared<Sample>(data, frames, sample_rate);
+		auto psample = std::make_shared<Sample>(SampleBuffer{std::move(data), sample_rate});
 		psample->setFrequency(root_freq / 1000.0f);
 
 		if( modes & MODES_LOOPING )
@@ -363,8 +363,6 @@ PatmanInstrument::LoadError PatmanInstrument::loadPatch(
 		}
 
 		m_patchSamples.push_back(psample);
-
-		delete[] data;
 	}
 	fclose( fd );
 	return( LoadError::OK );

plugins/SlicerT/SlicerT.cpp

@@ -306,7 +306,7 @@ std::vector<Note> SlicerT::getMidi()
 
 void SlicerT::updateFile(QString file)
 {
-	if (auto buffer = SampleBuffer::fromFile(file)) { m_originalSample = Sample(std::move(buffer)); }
+	if (auto buffer = SampleBuffer::fromFile(file)) { m_originalSample = Sample(std::move(buffer.value())); }
 
 	findBPM();
 	findSlices();
@@ -351,8 +351,10 @@ void SlicerT::loadSettings(const QDomElement& element)
 	{
 		if (QFileInfo(PathUtil::toAbsolute(srcFile)).exists())
 		{
-			auto buffer = SampleBuffer::fromFile(srcFile);
-			m_originalSample = Sample(std::move(buffer));
+			if (auto buffer = SampleBuffer::fromFile(srcFile))
+			{
+				m_originalSample = Sample(std::move(buffer.value()));
+			}
 		}
 		else
 		{
@@ -362,8 +364,10 @@ void SlicerT::loadSettings(const QDomElement& element)
 	}
 	else if (auto sampleData = element.attribute("sampledata"); !sampleData.isEmpty())
 	{
-		auto buffer = SampleBuffer::fromBase64(sampleData);
-		m_originalSample = Sample(std::move(buffer));
+		if (auto buffer = SampleBuffer::fromBase64(sampleData, Engine::audioEngine()->outputSampleRate()))
+		{
+			m_originalSample = Sample{std::move(buffer.value())};
+		}
 	}
 
 	if (!element.attribute("totalSlices").isEmpty())