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#pragma once
#include <cstdint>
namespace audio {
extern const std::size_t kMaxFrameSize;
class IAudioElement {
public:
virtual ~IAudioElement();
enum CommandType {
/*
* Sets the sequence number of the most recent byte stream. Any commands
* received that have a lower sequence number than this will be discarded.
*/
SEQUENCE_NUMBER,
/*
* Instructs this element to read a specific number of bytes from its
* input buffer.
*/
READ_FRAME,
/*
* Represents an element-specific command. This handling of this is
* delegated to element implementations.
*/
ELEMENT,
/* Instructs this element to shut down. */
QUIT,
};
struct Command {
CommandType type;
uint8_t sequence_number;
union {
void* data;
std::size_t frame_size;
};
};
/*
* Returns a queue that should be used for all communication with this
* element.
*/
virtual auto InputCommandQueue() -> QueueHandle_t = 0;
/*
* Returns a buffer that will be used to stream input bytes to this element.
* This may be NULL, if this element represents a source, e.g. a FATFS
* reader.
*/
virtual auto InputBuffer() -> StreamBufferHandle_t = 0;
/*
* Called when an element-specific command has been received.
*/
virtual auto ProcessElementCommand(void* command) -> void = 0;
virtual auto SkipElementCommand(void* command) -> void = 0;
/*
* Called with the result of a read bytes command.
*/
virtual auto ProcessData(uint8_t* data, uint16_t length) -> void = 0;
/*
* Called periodically when there are no pending commands.
*/
virtual auto ProcessIdle() -> void = 0;
};
} // namespace audio
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