Class: Racket::Misc::TLV

Inherits:
Object
  • Object
show all
Defined in:
lib/racket/misc/tlv.rb

Overview

Everything after the TLV is stuff into rest

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(ts, ls, lbytes = 1, tlinclude = false) ⇒ TLV

Create a new TLV which requires ts bytes for the type field and ls bytes for the length field, where (optionally) the value in length is a multiple of lbytes and (optionally) whether or not the length field indicates the total length of the TLV of just that of the value



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# File 'lib/racket/misc/tlv.rb', line 40

def initialize(ts, ls, lbytes=1, tlinclude=false)
  @ts = ts
  @ls = ls
  @lbytes = lbytes
  @tlinclude = tlinclude
end

Instance Attribute Details

#lbytes ⇒ Object

Returns the value of attribute lbytes.



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# File 'lib/racket/misc/tlv.rb', line 33

def lbytes
  @lbytes
end

#length ⇒ Object

Returns the value of attribute length.



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# File 'lib/racket/misc/tlv.rb', line 33

def length
  @length
end

#rest ⇒ Object

Returns the value of attribute rest.



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# File 'lib/racket/misc/tlv.rb', line 33

def rest
  @rest
end

#tlinclude ⇒ Object

Returns the value of attribute tlinclude.



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# File 'lib/racket/misc/tlv.rb', line 33

def tlinclude
  @tlinclude
end

#type ⇒ Object

Returns the value of attribute type.



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# File 'lib/racket/misc/tlv.rb', line 33

def type
  @type
end

#value ⇒ Object

Returns the value of attribute value.



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# File 'lib/racket/misc/tlv.rb', line 33

def value
  @value
end

Instance Method Details

#decode(data) ⇒ Object

Given data, return the type, length, value and rest values as dictated by this instance.



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# File 'lib/racket/misc/tlv.rb', line 49

def decode(data)
  s = "#{punpack_string(@ts)}#{punpack_string(@ls)}"
  type, length, tmp = data.unpack("#{s}a*")
  if (type.nil? or length.nil?)
    nil
  else
    elength = (length * lbytes) - (@tlinclude ? (@ls + @ts) : 0) 
    value, rest = tmp.unpack("a#{elength}a*")
    if (value.empty? and length > 0)
      nil
    else
      [type, length, value, rest]
    end
  end
end

#decode!(data) ⇒ Object 



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# File 'lib/racket/misc/tlv.rb', line 65

def decode!(data)
  @type, @length, @value, @rest = self.decode(data)
end

#encode ⇒ Object

Return a string suitable for use elswhere.



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# File 'lib/racket/misc/tlv.rb', line 70

def encode
  s = "#{punpack_string(@ts)}#{punpack_string(@ls)}"
  [@type, @length, @value].pack("#{s}a*")
end

#to_s ⇒ Object 



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# File 'lib/racket/misc/tlv.rb', line 75

def to_s
  encode
end

#to_str ⇒ Object 



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# File 'lib/racket/misc/tlv.rb', line 79

def to_str
  encode
end