Improve decoder's interface to accept streams

1 files changed, 73 insertions, 0 deletions

diff --git a/src/tangara/audio/processor.hpp b/src/tangara/audio/processor.hpp
new file mode 100644
index 00000000..8f197d97
--- /dev/null
+++ b/src/tangara/audio/processor.hpp
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <cstdint>
+#include <memory>
+
+#include "audio/audio_events.hpp"
+#include "audio/audio_sink.hpp"
+#include "audio/audio_source.hpp"
+#include "audio/resample.hpp"
+#include "codec.hpp"
+#include "sample.hpp"
+
+namespace audio {
+
+/*
+ * Handle to a persistent task that converts samples between formats (sample
+ * rate, channels, bits per sample), in order to put samples in the preferred
+ * format of the current output device. The resulting samples are forwarded
+ * to the output device's sink stream.
+ */
+class SampleProcessor {
+ public:
+  SampleProcessor();
+  ~SampleProcessor();
+
+  auto SetOutput(std::shared_ptr<IAudioOutput>) -> void;
+
+  auto beginStream(std::shared_ptr<TrackInfo>) -> void;
+  auto continueStream(std::span<sample::Sample>) -> void;
+  auto endStream() -> void;
+
+ private:
+  auto Main() -> void;
+
+  auto handleBeginStream(std::shared_ptr<TrackInfo>) -> void;
+  auto handleContinueStream(size_t samples_available) -> void;
+  auto handleEndStream() -> void;
+
+  auto handleSamples(std::span<sample::Sample>) -> size_t;
+
+  auto sendToSink(std::span<sample::Sample>) -> void;
+
+  struct Args {
+    std::shared_ptr<TrackInfo>* track;
+    size_t samples_available;
+    bool is_end_of_stream;
+  };
+  QueueHandle_t commands_;
+
+  std::unique_ptr<Resampler> resampler_;
+
+  StreamBufferHandle_t source_;
+  std::span<sample::Sample> input_buffer_;
+  std::span<std::byte> input_buffer_as_bytes_;
+
+  std::span<sample::Sample> resampled_buffer_;
+
+  std::shared_ptr<IAudioOutput> sink_;
+  IAudioOutput::Format source_format_;
+  IAudioOutput::Format target_format_;
+  size_t leftover_bytes_;
+
+  uint32_t samples_sunk_;
+};
+
+}  // namespace audio