Userspace: Add simple AudioServer and LibAudio

userspace/libraries/LibAudio/include/LibAudio/Audio.h

@@ -0,0 +1,64 @@
+#pragma once
+
+#include <BAN/Atomic.h>
+#include <BAN/StringView.h>
+#include <BAN/Vector.h>
+
+#include <LibAudio/AudioLoader.h>
+
+namespace LibAudio
+{
+
+	static constexpr BAN::StringView s_audio_server_socket = "/tmp/audio-server.socket"_sv;
+
+	struct AudioBuffer
+	{
+		using sample_t = double;
+
+		uint32_t sample_rate;
+		uint32_t channels;
+
+		uint32_t capacity;
+		BAN::Atomic<uint32_t> tail { 0 };
+		BAN::Atomic<uint32_t> head { 0 };
+		sample_t samples[/* capacity */];
+	};
+
+	class Audio
+	{
+		BAN_NON_COPYABLE(Audio);
+
+	public:
+		static BAN::ErrorOr<Audio> load(BAN::StringView path);
+		static BAN::ErrorOr<Audio> random(uint32_t samples);
+		~Audio() { clear(); }
+
+		Audio(Audio&& other) { *this = BAN::move(other); }
+		Audio& operator=(Audio&& other);
+
+		BAN::ErrorOr<void> start();
+
+		bool is_playing() const { return m_audio_buffer->tail != m_audio_buffer->head; }
+		void update();
+
+	private:
+		Audio() = default;
+		Audio(BAN::UniqPtr<AudioLoader>&& audio_loader)
+			: m_audio_loader(BAN::move(audio_loader))
+		{ }
+
+		void clear();
+
+		BAN::ErrorOr<void> initialize(uint32_t total_samples);
+
+	private:
+		int m_server_fd { -1 };
+
+		BAN::UniqPtr<AudioLoader> m_audio_loader;
+
+		long m_smo_key { -1 };
+		size_t m_smo_size { 0 };
+		AudioBuffer* m_audio_buffer { nullptr };
+	};
+
+}

userspace/libraries/LibAudio/include/LibAudio/AudioLoader.h

@@ -0,0 +1,32 @@
+#pragma once
+
+#include <BAN/StringView.h>
+#include <BAN/UniqPtr.h>
+
+namespace LibAudio
+{
+
+	class AudioLoader
+	{
+		BAN_NON_COPYABLE(AudioLoader);
+		BAN_NON_MOVABLE(AudioLoader);
+
+	public:
+		static BAN::ErrorOr<BAN::UniqPtr<AudioLoader>> load(BAN::StringView path);
+		virtual ~AudioLoader();
+
+		virtual uint32_t channels() const = 0;
+		virtual uint32_t sample_rate() const = 0;
+		virtual uint32_t samples_remaining() const = 0;
+
+		virtual double get_sample() = 0;
+
+	protected:
+		AudioLoader() = default;
+
+	private:
+		void* m_mmap_addr { nullptr };
+		size_t m_mmap_size { 0 };
+	};
+
+}

userspace/libraries/LibAudio/include/LibAudio/AudioLoaders/WAVLoader.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <LibAudio/AudioLoader.h>
+
+#include <BAN/ByteSpan.h>
+
+namespace LibAudio
+{
+
+	class WAVAudioLoader : public AudioLoader
+	{
+	public:
+		enum FormatCode : uint16_t
+		{
+			WAVE_FORMAT_PCM        = 0x01,
+			WAVE_FORMAT_IEEE_FLOAT = 0x03,
+		};
+
+	public:
+		static bool can_load_from(BAN::ConstByteSpan data);
+		static BAN::ErrorOr<BAN::UniqPtr<AudioLoader>> create(BAN::ConstByteSpan data);
+
+		uint32_t channels() const override { return m_channels; }
+		uint32_t sample_rate() const override { return m_sample_rate; }
+		uint32_t samples_remaining() const override { return m_total_samples - m_current_sample; }
+
+		double get_sample() override;
+
+	private:
+		uint32_t m_channels { 0 };
+		uint32_t m_sample_rate { 0 };
+		uint32_t m_total_samples { 0 };
+
+		FormatCode m_sample_format;
+		uint16_t m_bits_per_sample { 0 };
+		size_t m_current_sample { 0 };
+		BAN::ConstByteSpan m_sample_data;
+	};
+
+}