Class: Erlang::Decode

Inherits:
Object
  • Object
show all
Includes:
External::Types
Defined in:
lib/rinterface/erlang/decoder.rb

Defined Under Namespace

Classes: DecodeError

Constant Summary

Constants included from External::Types

External::Types::ATOM, External::Types::BIN, External::Types::FLOAT, External::Types::FUN, External::Types::INT, External::Types::LARGE_BIGNUM, External::Types::LARGE_TUPLE, External::Types::LIST, External::Types::NEW_FLOAT, External::Types::NEW_FUN, External::Types::NEW_REF, External::Types::NIL, External::Types::PID, External::Types::PORT, External::Types::REF, External::Types::SMALL_BIGNUM, External::Types::SMALL_INT, External::Types::SMALL_TUPLE, External::Types::STRING

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(ins) ⇒ Decode

Returns a new instance of Decode.



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# File 'lib/rinterface/erlang/decoder.rb', line 16

def initialize(ins)
  @in = ins
  @peeked = ""
end

Instance Attribute Details

#in ⇒ Object

Returns the value of attribute in.



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# File 'lib/rinterface/erlang/decoder.rb', line 6

def in
  @in
end

Class Method Details

.read_any_from(string) ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 12

def self.read_any_from(string)
  new(StringIO.new(string)).read_any
end

.read_bits(string) ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 8

def self.read_bits(string)
  new(StringIO.new(string))
end

Instance Method Details

#fail(str) ⇒ Object

Raises:



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# File 'lib/rinterface/erlang/decoder.rb', line 217

def fail(str)
  raise DecodeError, str
end

#peek(length) ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 66

def peek(length)
  if length <= @peeked.length
    @peeked[0...length]
  else
    read_bytes = @in.read(length - @peeked.length)
    @peeked << read_bytes if read_bytes
    @peeked
  end
end

#peek_1 ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 76

def peek_1
  peek(1).unpack("C").first
end

#peek_2 ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 80

def peek_2
  peek(2).unpack("n").first
end

#read(length) ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 48

def read(length)
  # p @peeked
  if length < @peeked.length
    result = @peeked[0...length]
    @peeked = @peeked[length..-1]
    length = 0
  else
    result = @peeked
    @peeked = ''
    length -= result.length
  end

  if length > 0
    result << @in.read(length)
  end
  result
end

#read_1 ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 84

def read_1
  read(1).unpack("C").first
end

#read_2 ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 88

def read_2
  read(2).unpack("n").first
end

#read_4 ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 92

def read_4
  read(4).unpack("N").first
end

#read_any ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 21

def read_any
  raise "Bad Math on Version" unless read_1 == External::VERSION
  read_any_raw
end

#read_any_raw ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 26

def read_any_raw
  case peek_1
  when ATOM then read_atom
  when SMALL_INT then read_small_int
  when INT then read_int
  when SMALL_BIGNUM then read_small_bignum
  when LARGE_BIGNUM then read_large_bignum
  when NEW_FLOAT then read_double
  when FLOAT then read_float
  when NEW_REF then read_new_reference
  when PID then read_pid
  when SMALL_TUPLE then read_small_tuple
  when LARGE_TUPLE then read_large_tuple
  when NIL then read_nil
  when STRING then read_erl_string
  when LIST then read_list
  when BIN then read_bin
  else
    fail("Unknown term tag: #{peek_1}")
  end
end

#read_atom ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 100

def read_atom
  fail("Invalid Type, not an atom") unless read_1 == ATOM
  length = read_2
  if length == 0
    ''
  else
    read_string(length).to_sym
  end
end

#read_bin ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 210

def read_bin
  fail("Invalid Type, not an erlang binary") unless read_1 == BIN
  length = read_4
  read_string(length)
end

#read_double ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 149

def read_double
  fail("Invalid Type, not a double") unless read_1 == NEW_FLOAT
  read_string(64).unpack('G').first
end

#read_erl_string ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 196

def read_erl_string
  fail("Invalid Type, not an erlang string") unless read_1 == STRING
  length = read_2
  read_string(length).unpack('C' * length)
end

#read_float ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 154

def read_float
  fail("Invalid Type, not a float") unless read_1 == FLOAT

  read_string(32).unpack('g').first
end

#read_int ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 115

def read_int
  fail("Invalid Type, not an int") unless read_1 == INT
  value = read_4
  negative = (value >> 31)[0] == 1
  value = (value - (1 << 32)) if negative
  value = Fixnum.induced_from(value)
end

#read_large_bignum ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 136

def read_large_bignum
  fail("Invalid Type, not a large bignum") unless read_1 == LARGE_BIGNUM
  size = read_4
  sign = read_1
  bytes = read_string(size).unpack("C" * size)
  added = bytes.zip((0..bytes.length).to_a).inject(0) do |result, byte_index|
    byte, index = *byte_index
    value = (byte * (256 ** index))
    sign != 0 ? (result - value) : (result + value)
  end
  Bignum.induced_from(added)
end

#read_large_tuple ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 185

def read_large_tuple
  fail("Invalid Type, not a small tuple") unless read_1 == LARGE_TUPLE
  arity = read_4
  (0...arity).map{|i| read_any_raw}
end

#read_list ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 202

def read_list
  fail("Invalid Type, not an erlang list") unless read_1 == LIST
  length = read_4
  list = (0...length).map{|i| read_any_raw}
  read_1
  list
end

#read_new_reference ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 160

def read_new_reference
  fail("Invalid Type, not a new-style reference") unless read_1 == NEW_REF
  size = read_2
  node = read_atom
  creation = read_1
  id = (0...size).map{|i| read_4 }
  NewReference.new(node, creation, id)
end

#read_nil ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 191

def read_nil
  fail("Invalid Type, not a nil list") unless read_1 == NIL
  []
end

#read_pid ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 169

def read_pid
  fail("Invalid Type, not a pid") unless read_1 == PID
  node = read_atom
  id = read_4
  serial = read_4
  creation = read_1
  Terms::Pid.new(node, id, serial, creation)
end

#read_small_bignum ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 123

def read_small_bignum
  fail("Invalid Type, not a small bignum") unless read_1 == SMALL_BIGNUM
  size = read_1
  sign = read_1
  bytes = read_string(size).unpack("C" * size)
  added = bytes.zip((0..bytes.length).to_a).inject(0) do |result, byte_index|
    byte, index = *byte_index
    value = (byte * (256 ** index))
    sign != 0 ? (result - value) : (result + value)
  end
  Bignum.induced_from(added)
end

#read_small_int ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 110

def read_small_int
  fail("Invalid Type, not a small int") unless read_1 == SMALL_INT
  read_1
end

#read_small_tuple ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 178

def read_small_tuple
  fail("Invalid Type, not a small tuple") unless read_1 == SMALL_TUPLE
  arity = read_1

  (0...arity).map{|i| read_any_raw }
end

#read_string(length) ⇒ Object 



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# File 'lib/rinterface/erlang/decoder.rb', line 96

def read_string(length)
  read(length)
end