Class: BinParserElement

Inherits:
Object
  • Object
show all
Defined in:
lib/binp.rb

Defined Under Namespace

Modules: Endianness, Type

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, offset, size, endianness) ⇒ BinParserElement

Returns a new instance of BinParserElement.



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# File 'lib/binp.rb', line 22

def initialize(name, offset, size, endianness)
  @name = name
  @offset = offset
  @size = size
  @endianness = endianness
end

Instance Attribute Details

#endianness ⇒ Object (readonly)

Returns the value of attribute endianness.



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# File 'lib/binp.rb', line 20

def endianness
  @endianness
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/binp.rb', line 20

def name
  @name
end

#offset ⇒ Object (readonly)

Returns the value of attribute offset.



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# File 'lib/binp.rb', line 20

def offset
  @offset
end

#size ⇒ Object (readonly)

Returns the value of attribute size.



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# File 'lib/binp.rb', line 20

def size
  @size
end

Class Method Details

.calculate_pack_template_string(size) ⇒ Object 



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# File 'lib/binp.rb', line 79

def self.calculate_pack_template_string(size)
  'C' * size
end

.calculate_unpack_template_string(type, endianness) ⇒ Object

see: docs.ruby-lang.org/ja/latest/doc/pack_template.html



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# File 'lib/binp.rb', line 47

def self.calculate_unpack_template_string(type, endianness)

  # 特殊な条件
  case type
  when BinParserElement::Type::UINT16
    if endianness == BinParserElement::Endianness::BIG_ENDIAN
      # ビッグエンディアン、符号なし 16 bit 整数
      return 'n'
    else
      # リトルエンディアン、符号なし 16 bit 整数
      return 'v'
    end
  when BinParserElement::Type::UINT32
    if endianness == BinParserElement::Endianness::BIG_ENDIAN
      # ビッグエンディアン、符号あり 32 bit 整数
      return 'N'
    else
      # リトルエンディアン、符号あり 32 bit 整数
      return 'V'
    end
  when BinParserElement::Type::UINT8
    # 符号なし 8 bit 整数
    return 'C'
  when BinParserElement::Type::INT8
    # 符号あり 8 bit 整数
    return 'c'
  end

  # その他
  type[:value] + endianness[:value]
end

.get_flags(uint8_array, config) ⇒ Object 



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# File 'lib/binp.rb', line 94

def self.get_flags(uint8_array, config)
  offset = config['offset']
  layout = config['layout']
  target = uint8_array.slice(offset, 1)
  layout.map { |e|
    c = config.dup
    c['name'] = e['name']

    # ビットが立っているかの確認
    c['value'] = target[0] & (1 << e['position'])

    # true_label, false_label が存在すればそれに設定。
    # 存在しなければデフォルト値('ON', 'OFF')に設定。
    if c['value'] != 0
      c['value'] = e.fetch('true_label', 'ON')
    else
      c['value'] = e.fetch('false_label', 'OFF')
    end
    c
  }
end

.get_value(uint8_array, offset, size, type, endianness, value_labels = {}) ⇒ Object 



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# File 'lib/binp.rb', line 83

def self.get_value(uint8_array, offset, size, type, endianness, value_labels={})
  target = uint8_array.slice(offset, size)
  pack_template_string = calculate_pack_template_string(size)
  unpack_template_string = calculate_unpack_template_string(type, endianness)
  value = target.pack(pack_template_string).unpack(unpack_template_string)[0]

  # value_label が設定されている数値であれば、それに置き換える
  value_labels ||= {}
  value_labels.fetch(value, value)
end