paiza.ioでelixir その177

概要

paiza.ioでelixirやってみた。
aiffファイルを解析してみた。

参考にしたページ

サンプルコード

:inets.start
:ssl.start

defmodule CommonChunk do
	defstruct [:id, :size, :num_channels, :num_sample_frames, :sample_size, :sample_rate, ]
	def new(id, size,
		<<
			num_channels :: unsigned-integer-size(16),
			num_sample_frames :: unsigned-integer-size(32),
			sample_size :: unsigned-integer-size(16),
			_x :: unsigned-integer-size(16),
			sample_rate :: unsigned-integer-size(16),
			_y :: binary
		>>) do
		%CommonChunk{
			id: id,
			size: size,
			num_channels: num_channels,
			num_sample_frames: num_sample_frames,
			sample_size: sample_size,
			sample_rate: sample_rate,
		}
	end
end
defmodule SoundDataChunk do
	defstruct [:id, :size, :offset, :block_size, :sound_data, ]
	def new(
		<<
			id :: bitstring-size(32),
			size :: unsigned-integer-size(32),
			offset :: unsigned-integer-size(32),
			block_size :: unsigned-integer-size(32),
			sound_data :: binary
		>>) do
		%SoundDataChunk{
			id: id,
			size: size,
			offset: offset,
			block_size: block_size,
			sound_data: sound_data,
		}
	end
end
defmodule FormChunk do
	defstruct [:id, :size, :type, :common, :sound_data]
	def new(
		<< 
			id :: bitstring-size(32), 
			size :: unsigned-integer-size(32),
			type :: bitstring-size(32),
			common_id :: unsigned-integer-size(32), 
			common_chunk_size :: unsigned-integer-size(32),
			common_data :: binary-size(common_chunk_size),
			sound_data_chunk :: binary
		>>) do
		%FormChunk{
			id: id,
			size: size,
			type: type,
			common: CommonChunk.new(common_id, common_chunk_size, common_data),
			sound_data: SoundDataChunk.new(sound_data_chunk)
		}
	end
end
defmodule Main do
	def main() do
		{:ok, {_status, _headers, body}} = :httpc.request('https://resolvenet.org/modules/contrib/webform/tests/files/sample.aiff')
		body = IO.iodata_to_binary(body)
	    IO.inspect FormChunk.new body
	end
end
Main.main

実行結果

%FormChunk{
  common: %CommonChunk{
    id: 1129270605,
    num_channels: 1,
    num_sample_frames: 37478,
    sample_rate: 44100,
    sample_size: 16,
    size: 18
  },
  id: "FORM",
  size: 75002,
  sound_data: %SoundDataChunk{
    block_size: 0,
    id: "SSND",
    offset: 0,
    size: 74964,
    sound_data: <<255, 0, 0, 0, 0, 0, 255, 0, 255, 0, 0, 0, 255, 0, 255, 0, 255,
      0, 0, 0, 0, 0, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255, 0, 0, 0,
      0, ...>>
  },
  type: "AIFF"
}

成果物

以上。