Class: Erlang::ETF::SmallBig

Inherits:
Object
  • Object
show all
Includes:
Term
Defined in:
lib/erlang/etf/small_big.rb

Overview

1 1 1 n
110 n Sign d(0) ... d(n-1)

Bignums are stored in unary form with a Sign byte that is 0 if the binum is positive and 1 if is negative. The digits are stored with the LSB byte stored first.

To calculate the integer the following formula can be used:

B = 256
(d0*B^0 + d1*B^1 + d2*B^2 + ... d(N-1)*B^(n-1))

(see SMALL_BIG_EXT)

Constant Summary collapse

UINT8 = 
Erlang::ETF::Term::UINT8
HEAD = 
(UINT8 + UINT8).freeze

Constants included from Term

Term::ATOM_CACHE_REF, Term::ATOM_EXT, Term::ATOM_INTERNAL_REF2, Term::ATOM_INTERNAL_REF3, Term::ATOM_UTF8_EXT, Term::BINARY_ENCODING, Term::BINARY_EXT, Term::BINARY_INTERNAL_REF, Term::BIT_BINARY_EXT, Term::BIT_BINARY_INTERNAL_REF, Term::COMPRESSED, Term::DIST_HEADER, Term::DOUBLE, Term::DOUBLEBE, Term::DOUBLELE, Term::ERLANG_MAGIC_BYTE, Term::EXPORT_EXT, Term::FLOAT_EXT, Term::FUN_EXT, Term::INT128, Term::INT128BE, Term::INT128LE, Term::INT16, Term::INT16BE, Term::INT16LE, Term::INT32, Term::INT32BE, Term::INT32LE, Term::INT64, Term::INT64BE, Term::INT64LE, Term::INT8, Term::INTEGER_EXT, Term::LARGE_BIG_EXT, Term::LARGE_TUPLE_EXT, Term::LIST_EXT, Term::MAP_EXT, Term::NEW_FLOAT_EXT, Term::NEW_FUN_EXT, Term::NEW_REFERENCE_EXT, Term::NIL_EXT, Term::PID_EXT, Term::PORT_EXT, Term::REFERENCE_EXT, Term::SINGLE, Term::SINGLEBE, Term::SINGLELE, Term::SMALL_ATOM_EXT, Term::SMALL_ATOM_UTF8_EXT, Term::SMALL_BIG_EXT, Term::SMALL_INTEGER_EXT, Term::SMALL_TUPLE_EXT, Term::STRING_EXT, Term::UINT128, Term::UINT128BE, Term::UINT128LE, Term::UINT16, Term::UINT16BE, Term::UINT16LE, Term::UINT32, Term::UINT32BE, Term::UINT32LE, Term::UINT64, Term::UINT64BE, Term::UINT64LE

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Term

#<=>, binary_encoding, #eql?, #erlang_external_type, #hash, included, #inspect, #to_erlang_etf

Constructor Details

#initialize(term) ⇒ SmallBig

Returns a new instance of SmallBig.

Raises:

  • (ArgumentError) 


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# File 'lib/erlang/etf/small_big.rb', line 45

def initialize(term)
  raise ArgumentError, "term must be of type Integer" if not Erlang.is_integer(term)
  @term = term
end

Class Method Details

.[](term) ⇒ Object 



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# File 'lib/erlang/etf/small_big.rb', line 31

def [](term)
  return term if term.kind_of?(Erlang::ETF::Term)
  term = Erlang.from(term)
  return new(term)
end

.erlang_load(buffer) ⇒ Object 



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# File 'lib/erlang/etf/small_big.rb', line 37

def erlang_load(buffer)
  n, sign, = buffer.read(2).unpack(HEAD)
  integer = Erlang::Binary.decode_unsigned(buffer.read(n), :little)
  integer = -integer if sign == 1
  return new(integer)
end

Instance Method Details

#erlang_dump(buffer = ::String.new.force_encoding(BINARY_ENCODING)) ⇒ Object 



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# File 'lib/erlang/etf/small_big.rb', line 50

def erlang_dump(buffer = ::String.new.force_encoding(BINARY_ENCODING))
  buffer << SMALL_BIG_EXT
  buffer << [Erlang::ETF.intlog2div8(@term), (@term < 0) ? 1 : 0].pack(HEAD)
  buffer << Erlang::Binary.encode_unsigned(@term.abs, :little)
  return buffer
end