1 files changed, 57 insertions, 0 deletions
diff --git a/src/audio/include/chunk.hpp b/src/audio/include/chunk.hpp
new file mode 100644
index 00000000..1351ecfb
--- /dev/null
+++ b/src/audio/include/chunk.hpp
@@ -0,0 +1,57 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <optional>
+#include <string>
+#include "esp-idf/components/cbor/tinycbor/src/cbor.h"
+#include "freertos/portmacro.h"
+#include "result.hpp"
+
+namespace audio {
+
+enum ChunkWriteResult {
+  // Returned when the callback does not write any data.
+  CHUNK_OUT_OF_DATA,
+  // Returned when there is an error encoding a chunk header using cbor.
+  CHUNK_ENCODING_ERROR,
+  // Returned when max_wait expires without room in the stream buffer becoming
+  // available.
+  CHUNK_WRITE_TIMEOUT,
+};
+
+/*
+ * Invokes the given callback to receive data, breaks the received data up into
+ * chunks with headers, and writes those chunks to the given output stream.
+ *
+ * The callback will be invoked with a byte buffer and its size. The callback
+ * should write as much data as it can to this buffer, and then return the
+ * number of bytes it wrote. Return a value of 0 to indicate that there is no
+ * more input to read.
+ */
+auto WriteChunksToStream(MessageBufferHandle_t *stream, uint8_t *working_buffer, size_t working_buffer_length, std::function<size_t(uint8_t*,size_t)> callback, TickType_t max_wait) -> EncodeWriteResult;
+
+  enum ChunkReadResult {
+    // Returned an error in parsing the cbor-encoded header.
+    CHUNK_DECODING_ERROR,
+    // Returned when max_wait expired before any data was read.
+    CHUNK_READ_TIMEOUT,
+    // Returned when a non-chunk message is received.
+    CHUNK_STREAM_ENDED,
+  };
+
+/*
+ * Reads chunks of data from the given input stream, and invokes the given
+ * callback to process each of them in turn.
+ * 
+ * The callback will be invoked with a byte buffer and its size. The callback
+ * should process as much data as it can from this buffer, and then return the
+ * number of bytes it was able to read. Any leftover bytes will be added as a
+ * prefix to the next chunk.
+ *
+ * If this function encounters a message in the stream that is not a chunk, it
+ * will place the message at the start of the working_buffer and then return.
+ */
+auto ReadChunksFromStream(MessageBufferHandle_t *stream, uint8_t *working_buffer, size_t working_buffer_length, std::function<size_t(uint8_t*,size_t)> callback, TickType_t max_wait) -> EncodeReadResult;
+
+} // namespace audio