Class: Codec

Inherits:
Object
  • Object
show all
Defined in:
lib/ruby-doom.rb

Class Method Summary collapse

Class Method Details

.decode(format, bytes) ⇒ Object

Accepts a format string like “sl48” and a byte array s - short l - long 4 - 4 byte string 8 - 8 bytes string



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# File 'lib/ruby-doom.rb', line 203

def Codec.decode(format, bytes)
  res = []
  ptr = 0
  format.split(//).each {|x|
    if x == "s"
      res << bytes.slice(ptr,2).pack("c2").unpack("s")[0]
      ptr += 2
    elsif x == "l"  
      res << bytes.slice(ptr,4).pack("C4").unpack("V")[0]
      ptr += 4
    elsif x == "4"
      res << Codec.unmarshal_string(bytes.slice(ptr,4))
      ptr += 4
    elsif x == "8"
      res << Codec.unmarshal_string(bytes.slice(ptr,8))
      ptr += 8
    else
      raise "Unknown character in decode format string " + format
    end
  }
  return res
end

.encode(format, values) ⇒ Object

Accepts a format string like “sl48” and an array of values



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# File 'lib/ruby-doom.rb', line 226

def Codec.encode(format, values)
  bytes = []  
  ptr = 0
  format.split(//).each {|x|
    if x == "s"
      bytes += [values[ptr]].pack("S").unpack("C2")
    elsif x == "l"  
      bytes += [values[ptr]].pack("N").unpack("C4").reverse
    elsif x == "4"
      bytes += Codec.marshal_string(values[ptr],4)
    elsif x == "8"
      bytes += Codec.marshal_string(values[ptr],8)
    else
      raise "Unknown character in decode format string " + format
    end
    ptr += 1
  }
  return bytes
end

.marshal_string(n, len) ⇒ Object 



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# File 'lib/ruby-doom.rb', line 248

def Codec.marshal_string(n,len)
  arr = n.unpack("C#{len}").compact
  if arr.size < len
    arr += Array.new(len-arr.size, 0)
  end
  arr
end

.unmarshal_string(a) ⇒ Object 



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# File 'lib/ruby-doom.rb', line 245

def Codec.unmarshal_string(a)
  a.pack("C*").strip
end