Class: Nl::Encoder

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(capacity = 4096) ⇒ Encoder

Returns a new instance of Encoder.



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# File 'lib/nl/encoder.rb', line 5

def initialize(capacity = 4096)
  @buffer = IO::Buffer.new(capacity)
  @position = 0
end

Instance Attribute Details

#position ⇒ Object (readonly)

Returns the value of attribute position.



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# File 'lib/nl/encoder.rb', line 3

def position
  @position
end

Instance Method Details

#align_to(alignment) ⇒ Object 



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# File 'lib/nl/encoder.rb', line 38

def align_to(alignment)
  if alignment > 1
    nposition = (@position + alignment - 1) & ~(alignment - 1)
    reserve(nposition - @position)
    @position = nposition
  end
end

#buffer ⇒ Object 



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# File 'lib/nl/encoder.rb', line 54

def buffer
  @buffer.slice(0, @position)
end

#measure(type, offset = 0) ⇒ Object 



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# File 'lib/nl/encoder.rb', line 58

def measure(type, offset = 0)
  before = @position
  yield
  after = @position
  put_value_at(before + offset, type, after - before)
end

#put_string(value) ⇒ Object 



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# File 'lib/nl/encoder.rb', line 17

def put_string(value)
  reserve(value.bytesize)
  @position += @buffer.set_string(value, @position)
end

#put_value(type, value) ⇒ Object 



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# File 'lib/nl/encoder.rb', line 28

def put_value(type, value)
  reserve(IO::Buffer.size_of(type))
  @position = @buffer.set_value(type, @position, value)
end

#put_value_at(offset, type, value) ⇒ Object 



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# File 'lib/nl/encoder.rb', line 46

def put_value_at(offset, type, value)
  @buffer.set_value(type, offset, value)
end

#put_values(types, values) ⇒ Object 



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# File 'lib/nl/encoder.rb', line 33

def put_values(types, values)
  reserve(IO::Buffer.size_of(types))
  @position = @buffer.set_values(types, @position, values)
end

#put_values_at(offset, types, values) ⇒ Object 



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# File 'lib/nl/encoder.rb', line 50

def put_values_at(offset, types, values)
  @buffer.set_values(types, offset, values)
end

#put_zstring(value) ⇒ Object 



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# File 'lib/nl/encoder.rb', line 22

def put_zstring(value)
  reserve(value.bytesize + 1)
  @position += @buffer.set_string(value, @position)
  @position = @buffer.set_value(:U8, @position, 0)
end

#reserve(size) ⇒ Object 



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# File 'lib/nl/encoder.rb', line 10

def reserve(size)
  nposition = @position + size
  if @buffer.size < nposition
    @buffer.resize([@buffer.size * 2, nposition].max)
  end
end