output/alsa: move class PeriodBuffer to lib/alsa/PeriodBuffer.hxx

src/output/plugins/AlsaOutputPlugin.cxx

@@ -20,6 +20,7 @@
 #include "config.h"
 #include "AlsaOutputPlugin.hxx"
 #include "lib/alsa/NonBlock.hxx"
+#include "lib/alsa/PeriodBuffer.hxx"
 #include "lib/alsa/Version.hxx"
 #include "../OutputAPI.hxx"
 #include "mixer/MixerList.hxx"
@@ -153,110 +154,7 @@ class AlsaOutput final
 	 */
 	boost::lockfree::spsc_queue<uint8_t> *ring_buffer;
 
-	class PeriodBuffer {
-		size_t capacity, head, tail;
-
-		uint8_t *buffer;
-
-	public:
-		PeriodBuffer() = default;
-		PeriodBuffer(const PeriodBuffer &) = delete;
-		PeriodBuffer &operator=(const PeriodBuffer &) = delete;
-
-		void Allocate(size_t n_frames, size_t frame_size) noexcept {
-			capacity = n_frames * frame_size;
-
-			/* reserve space for one more (partial) frame,
-			   to be able to fill the buffer with silence,
-			   after moving an unfinished frame to the
-			   end */
-			buffer = new uint8_t[capacity + frame_size - 1];
-			head = tail = 0;
-		}
-
-		void Free() noexcept {
-			delete[] buffer;
-		}
-
-		bool IsEmpty() const noexcept {
-			return head == tail;
-		}
-
-		bool IsFull() const noexcept {
-			return tail >= capacity;
-		}
-
-		uint8_t *GetTail() noexcept {
-			return buffer + tail;
-		}
-
-		size_t GetSpaceBytes() const noexcept {
-			assert(tail <= capacity);
-
-			return capacity - tail;
-		}
-
-		void AppendBytes(size_t n) noexcept {
-			assert(n <= capacity);
-			assert(tail <= capacity - n);
-
-			tail += n;
-		}
-
-		void FillWithSilence(const uint8_t *_silence,
-				     const size_t frame_size) noexcept {
-			size_t partial_frame = tail % frame_size;
-			auto *dest = GetTail() - partial_frame;
-
-			/* move the partial frame to the end */
-			std::copy(dest, GetTail(), buffer + capacity);
-
-			size_t silence_size = capacity - tail - partial_frame;
-			std::copy_n(_silence, silence_size, dest);
-
-			tail = capacity + partial_frame;
-		}
-
-		const uint8_t *GetHead() const noexcept {
-			return buffer + head;
-		}
-
-		snd_pcm_uframes_t GetFrames(size_t frame_size) const noexcept {
-			return (tail - head) / frame_size;
-		}
-
-		void ConsumeBytes(size_t n) noexcept {
-			head += n;
-
-			assert(head <= capacity);
-
-			if (head >= capacity) {
-				tail -= head;
-				/* copy the partial frame (if any)
-				   back to the beginning */
-				std::copy_n(GetHead(), tail, buffer);
-				head = 0;
-			}
-		}
-
-		void ConsumeFrames(snd_pcm_uframes_t n, size_t frame_size) noexcept {
-			ConsumeBytes(n * frame_size);
-		}
-
-		snd_pcm_uframes_t GetPeriodPosition(size_t frame_size) const noexcept {
-			return head / frame_size;
-		}
-
-		void Rewind() noexcept {
-			head = 0;
-		}
-
-		void Clear() noexcept {
-			head = tail = 0;
-		}
-	};
-
-	PeriodBuffer period_buffer;
+	Alsa::PeriodBuffer period_buffer;
 
 	/**
 	 * Protects #cond, #error, #drain.