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tangara-fw/src/audio/include/chunk.hpp

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/*
* Copyright 2023 jacqueline <me@jacqueline.id.au>
*
* SPDX-License-Identifier: GPL-3.0-only
*/
#pragma once
#include <cstddef>
#include <cstdint>
#include <memory>
#include <optional>
#include <string>
#include "freertos/FreeRTOS.h"
#include "cbor.h"
#include "freertos/message_buffer.h"
#include "freertos/portmacro.h"
#include "freertos/queue.h"
#include "result.hpp"
#include "span.hpp"
#include "stream_buffer.hpp"
namespace audio {
/**
* Utility for handling an input stream of chunk data, which simplifies needing
* access to blocks of data spanning two chunks.
*/
class ChunkReader {
public:
explicit ChunkReader(std::size_t chunk_size);
~ChunkReader();
auto HandleBytesLeftOver(std::size_t bytes_left) -> void;
auto HandleBytesUsed(std::size_t bytes_used) -> void;
/*
* 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 HandleNewData(cpp::span<std::byte> data) -> cpp::span<std::byte>;
auto GetLeftovers() -> cpp::span<std::byte>;
ChunkReader(const ChunkReader&) = delete;
ChunkReader& operator=(const ChunkReader&) = delete;
private:
std::byte* raw_working_buffer_;
cpp::span<std::byte> working_buffer_;
cpp::span<std::byte> last_data_in_working_buffer_;
std::size_t leftover_bytes_ = 0;
};
} // namespace audio