46 lines
1.2 KiB
Elixir
46 lines
1.2 KiB
Elixir
defmodule Circuits.UART.Framing.MIDI do
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@behaviour Circuits.UART.Framing
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alias __MODULE__.Buffer
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@moduledoc """
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Implements framing for the MIDI protocol.
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It doesn't decode any messages, it simply splits incoming serial frames apart
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into individual MIDI messages as per the specification.
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"""
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@impl true
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def init(_args), do: {:ok, Buffer.init()}
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@doc """
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Basically a no-op from a framing point of view. There's no intra-message
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delimeter required, so we simply return the data unchanged.
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"""
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@impl true
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def add_framing(data, state) do
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{:ok, data, state}
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end
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@doc """
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Process incoming data and break it apart into separate MIDI packets.
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"""
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@impl true
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def remove_framing(data, %Buffer{} = buffer) do
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buffer = Buffer.append(buffer, data)
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case Buffer.get_packets(buffer) do
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{:ok, messages, %Buffer{buffer: <<>>} = buffer} -> {:ok, messages, buffer}
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{:ok, messages, %Buffer{} = buffer} -> {:in_frame, messages, buffer}
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{:error, reason} -> {:error, reason}
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end
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end
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@impl true
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def frame_timeout(buffer), do: buffer
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@impl true
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def flush(direction, _buffer) when direction == :receive or direction == :both,
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do: Buffer.init()
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def flush(:transmit, buffer), do: buffer
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end
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