5 files changed, 68 insertions, 25 deletions

diff --git a/src/audio/include/audio_decoder.hpp b/src/audio/include/audio_decoder.hpp
index a4508c3e..4d2fd5f3 100644
--- a/src/audio/include/audio_decoder.hpp
+++ b/src/audio/include/audio_decoder.hpp
@@ -21,10 +21,11 @@ class AudioDecoder : public IAudioElement {
   auto SetInputBuffer(MessageBufferHandle_t*) -> void;
   auto SetOutputBuffer(MessageBufferHandle_t*) -> void;
 
-  auto ProcessStreamInfo(StreamInfo&& info) -> cpp::result<void, StreamError>;
+  auto ProcessStreamInfo(StreamInfo& info)
+      -> cpp::result<void, AudioProcessingError>;
   auto ProcessChunk(uint8_t* data, std::size_t length)
-      -> cpp::result<size_t, StreamError>;
-  auto ProcessIdle() -> cpp::result<void, StreamError>;
+      -> cpp::result<size_t, AudioProcessingError>;
+  auto ProcessIdle() -> cpp::result<void, AudioProcessingError>;
 
   AudioDecoder(const AudioDecoder&) = delete;
   AudioDecoder& operator=(const AudioDecoder&) = delete;
diff --git a/src/audio/include/audio_element.hpp b/src/audio/include/audio_element.hpp
index 13a48590..5b697784 100644
--- a/src/audio/include/audio_element.hpp
+++ b/src/audio/include/audio_element.hpp
@@ -15,8 +15,11 @@
 
 namespace audio {
 
-/* Errors that may be returned by any of the Process* methods. */
-enum StreamError {
+/*
+ * Errors that may be returned by any of the Process* methods of an audio
+ * element.
+ */
+enum AudioProcessingError {
   // Indicates that this element is unable to handle the upcoming chunks.
   UNSUPPORTED_STREAM,
   // Indicates an error with reading or writing stream data.
@@ -65,8 +68,8 @@ class IAudioElement {
    * Called when a StreamInfo message is received. Used to configure this
    * element in preperation for incoming chunks.
    */
-  virtual auto ProcessStreamInfo(StreamInfo&& info)
-      -> cpp::result<void, StreamError> = 0;
+  virtual auto ProcessStreamInfo(StreamInfo& info)
+      -> cpp::result<void, AudioProcessingError> = 0;
 
   /*
    * Called when a ChunkHeader message is received. Includes the data associated
@@ -75,14 +78,14 @@ class IAudioElement {
    * prepended to the next call.
    */
   virtual auto ProcessChunk(uint8_t* data, std::size_t length)
-      -> cpp::result<size_t, StreamError> = 0;
+      -> cpp::result<size_t, AudioProcessingError> = 0;
 
   /*
    * Called when there has been no data received over the input buffer for some
    * time. This could be used to synthesize output, or to save memory by
    * releasing unused resources.
    */
-  virtual auto ProcessIdle() -> cpp::result<void, StreamError> = 0;
+  virtual auto ProcessIdle() -> cpp::result<void, AudioProcessingError> = 0;
 
  protected:
   MessageBufferHandle_t* input_buffer_;
diff --git a/src/audio/include/fatfs_audio_input.hpp b/src/audio/include/fatfs_audio_input.hpp
index 6fe178ab..c54b32bd 100644
--- a/src/audio/include/fatfs_audio_input.hpp
+++ b/src/audio/include/fatfs_audio_input.hpp
@@ -19,10 +19,11 @@ class FatfsAudioInput : public IAudioElement {
   FatfsAudioInput(std::shared_ptr<drivers::SdStorage> storage);
   ~FatfsAudioInput();
 
-  auto ProcessStreamInfo(StreamInfo&& info) -> cpp::result<void, StreamError>;
+  auto ProcessStreamInfo(StreamInfo& info)
+      -> cpp::result<void, AudioProcessingError>;
   auto ProcessChunk(uint8_t* data, std::size_t length)
-      -> cpp::result<size_t, StreamError>;
-  auto ProcessIdle() -> cpp::result<void, StreamError>;
+      -> cpp::result<size_t, AudioProcessingError>;
+  auto ProcessIdle() -> cpp::result<void, AudioProcessingError>;
 
   auto SendChunk(uint8_t* buffer, size_t size) -> size_t;
 
diff --git a/src/audio/include/stream_info.hpp b/src/audio/include/stream_info.hpp
index ca28dd4e..47bcaa45 100644
--- a/src/audio/include/stream_info.hpp
+++ b/src/audio/include/stream_info.hpp
@@ -7,22 +7,11 @@
 #include "cbor.h"
 #include "result.hpp"
 
-#include "cbor_decoder.hpp"
-#include "cbor_encoder.hpp"
-
 namespace audio {
 
 class StreamInfo {
  public:
-  enum ParseError {
-    WRONG_TYPE,
-    MISSING_MAP,
-    CBOR_ERROR,
-  };
-
-  static auto Create(const uint8_t* buffer, size_t length)
-      -> cpp::result<StreamInfo, ParseError>;
-  StreamInfo(cbor::MapDecoder*);
+  static auto Parse(CborValue& container) -> cpp::result<StreamInfo, CborError>;
 
   StreamInfo() = default;
   StreamInfo(const StreamInfo&) = default;
@@ -38,7 +27,7 @@ class StreamInfo {
     return sample_rate_;
   }
 
-  auto WriteToMap(cbor::Encoder& encoder) -> cpp::result<size_t, CborError>;
+  auto Encode(CborEncoder& enc) -> std::optional<CborError>;
 
  private:
   std::optional<std::string> path_;
diff --git a/src/audio/include/stream_message.hpp b/src/audio/include/stream_message.hpp
index 2791dcd8..cbd7c733 100644
--- a/src/audio/include/stream_message.hpp
+++ b/src/audio/include/stream_message.hpp
@@ -1,11 +1,60 @@
 #pragma once
 
+#include <stdint.h>
+
+#include <functional>
+#include <optional>
+
+#include "cbor.h"
+#include "result.hpp"
+
 namespace audio {
 
+extern const int kEncoderFlags;
+extern const int kDecoderFlags;
+
 enum MessageType {
   TYPE_UNKNOWN,
   TYPE_CHUNK_HEADER,
   TYPE_STREAM_INFO,
 };
 
+template <typename Writer>
+auto WriteMessage(MessageType type,
+                  Writer&& writer,
+                  uint8_t* buffer,
+                  size_t length) -> cpp::result<size_t, CborError> {
+  CborEncoder root;
+  CborEncoder container;
+
+  cbor_encoder_init(&root, buffer, length, kEncoderFlags);
+  cbor_encoder_create_array(&root, &container, 2);
+  cbor_encode_uint(&container, type);
+
+  std::optional<CborError> inner_err = std::invoke(writer, container);
+  if (inner_err) {
+    return cpp::fail(inner_err.value());
+  }
+
+  cbor_encoder_close_container(&root, &container);
+  return cbor_encoder_get_buffer_size(&root, buffer);
+}
+
+template <typename Result, typename Reader>
+auto ReadMessage(Reader&& reader, uint8_t* buffer, size_t length)
+    -> cpp::result<Result, CborError> {
+  CborParser parser;
+  CborValue root;
+  CborValue container;
+
+  cbor_parser_init(buffer, length, kDecoderFlags, &parser, &root);
+  cbor_value_enter_container(&root, &container);
+  // Skip the type header
+  cbor_value_advance_fixed(&container);
+
+  return std::invoke(reader, container);
+}
+
+auto ReadMessageType(uint8_t* buffer, size_t length) -> MessageType;
+
 }  // namespace audio