Class: Pack::Stream

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(input, buffer = "") ⇒ Stream

Returns a new instance of Stream.



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# File 'lib/pack/stream.rb', line 8

def initialize(input, buffer = "")
  @input   = input
  @digest  = Digest::SHA1.new
  @offset  = 0
  @buffer  = new_byte_string.concat(buffer)
  @capture = nil
end

Instance Attribute Details

#digest ⇒ Object (readonly)

Returns the value of attribute digest.



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# File 'lib/pack/stream.rb', line 6

def digest
  @digest
end

#offset ⇒ Object (readonly)

Returns the value of attribute offset.



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# File 'lib/pack/stream.rb', line 6

def offset
  @offset
end

Instance Method Details

#capture ⇒ Object 



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# File 'lib/pack/stream.rb', line 16

def capture
  @capture = new_byte_string
  result   = [yield, @capture]

  @digest.update(@capture)
  @capture = nil

  result
end

#read(size) ⇒ Object 



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# File 'lib/pack/stream.rb', line 32

def read(size)
  data = read_buffered(size)
  update_state(data)
  data
end

#read_nonblock(size) ⇒ Object 



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# File 'lib/pack/stream.rb', line 38

def read_nonblock(size)
  data = read_buffered(size, false)
  update_state(data)
  data
end

#readbyte ⇒ Object 



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# File 'lib/pack/stream.rb', line 44

def readbyte
  read(1).bytes.first
end

#seek(amount, whence = IO::SEEK_SET) ⇒ Object 



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# File 'lib/pack/stream.rb', line 48

def seek(amount, whence = IO::SEEK_SET)
  return unless amount < 0

  data = @capture.slice!(amount .. -1)
  @buffer.prepend(data)
  @offset += amount
end

#verify_checksum ⇒ Object 



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# File 'lib/pack/stream.rb', line 26

def verify_checksum
  unless read_buffered(20) == @digest.digest
    raise InvalidPack, "Checksum does not match value read from pack"
  end
end