Class: TSparser::Binary

Inherits:
String
  • Object
show all
Defined in:
lib/binary.rb

Defined Under Namespace

Classes: BinaryException

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(byte_string = nil) ⇒ Binary

“byte_string” is string encoded as ASCII_8BIT (BINARY).



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# File 'lib/binary.rb', line 12

def initialize(byte_string=nil)
  byte_string ||= "".encode(Encoding::ASCII_8BIT)
  if byte_string.encoding != Encoding::ASCII_8BIT
    raise BinaryException.new("byte_string's encoding should be ASCII_8BIT(BINARY) " +
                              "(this is #{byte_string.encoding})")
  end
  super(byte_string)
end

Class Method Details

.from_int(*integers) ⇒ Object 



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# File 'lib/binary.rb', line 7

def self.from_int(*integers)
  return new(integers.pack("C*"))
end

Instance Method Details

#&(byte_integer) ⇒ Object 



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# File 'lib/binary.rb', line 75

def &(byte_integer)
  if byte_integer < 0x00 || byte_integer > 0xFF
    raise BinaryException.new("Can't apply operator& with integer #{byte_integer}.")
  end
  if self.length != 1
    raise BinaryException.new("Can't apply operator& on bytes #{self}.")
  end
  return Binary.from_int(self.to_i(0) & byte_integer)
end

#<=>(integer) ⇒ Object

Comparator to Integer



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# File 'lib/binary.rb', line 52

def <=>(integer)
  return super unless integer.is_a?(Integer)
  unless self.length == 1
    raise BinaryException.new("Can't compare non-single byte with integer.")
  end
  return self.to_i(0) <=> integer
end

#b(byte_index, bit_range = nil) ⇒ Object

Return Integer that is converted from bits specified by “bit_range” (arg2) in byte specified by “byte_index” (arg1).

Warning: Bit index is from right to left. So, LSB’s position is 0, MSB’s is 7



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# File 'lib/binary.rb', line 25

def b(byte_index, bit_range=nil)
  byte_num = self[byte_index].unpack("C")[0]
  return byte_num unless bit_range
  return sub_integer(byte_num, bit_range)
end

#bit_pointer ⇒ Object 



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# File 'lib/binary.rb', line 190

def bit_pointer
  @bit_pointer ||= 0
  return @bit_pointer
end

#dump ⇒ Object 



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# File 'lib/binary.rb', line 85

def dump
  bytes = []
  each_byte do |byte|
    bytes << sprintf("%02X", byte)
  end
  return bytes.join(" ")
end

#from(start_position) ⇒ Object

Generate new Binary instance that is subsequence of self (from specified position to end).



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# File 'lib/binary.rb', line 61

def from(start_position)
  unless start_position < self.length
    raise BinaryException.new("starting point must should be less than length")
  end
  return self[start_position, self.length - start_position]
end

#join(*binaries) ⇒ Object

Generate new Binary instance that is joined from “self”, “arg1”, “arg2”, … (in order).



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# File 'lib/binary.rb', line 69

def join(*binaries)
  return binaries.inject(self) do |combined, binary|
    Binary.new(combined + binary)
  end
end

#last_read_byte ⇒ Object 



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# File 'lib/binary.rb', line 176

def last_read_byte
  return Binary.new(self[bit_pointer-1])
end

#read_bit_as_binary(bitlen) ⇒ Object

Read specified length of bits and return as Binary instance. Bit pointer proceed for that length.

Warning: “bitlen” must be integer of multiple of 8, and bit pointer must be pointing start of byte.



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# File 'lib/binary.rb', line 154

def read_bit_as_binary(bitlen)
  unless bit_pointer % 8 == 0
    raise BinaryException.new("Bit pointer must be pointing start of byte. " +
                              "But now pointing #{bit_pointer}.")
  end
  unless bitlen % 8 == 0
    raise BinaryException.new("Arg must be integer of multiple of 8. " +
                              "But you specified #{bitlen}.")
  end
  if self.length - bit_pointer/8 < bitlen/8
    raise BinaryException.new("Rest of self length(#{self.length - bit_pointer/8}byte)" +
                              " is shorter than specified byte length(#{bitlen/8}byte).")
  end
  response = self[bit_pointer/8, bitlen/8]
  bit_pointer_inc(bitlen)
  return response
end

#read_bit_as_integer(bitlen) ⇒ Object

Read specified length of bits and return as Integer instance. Bit pointer proceed for that length.



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# File 'lib/binary.rb', line 100

def read_bit_as_integer(bitlen)
  if self.length * 8 - bit_pointer < bitlen
    raise BinaryException.new("Rest of self length(#{self.length * 8 - bit_pointer}bit) "+
                              "is shorter than specified bit length(#{bitlen}bit).")
  end
  if bit_pointer % 8 == 0 && bitlen % 8 == 0
    return read_byte_as_integer(bitlen/8)
  else
    response = 0
    bitlen.times do
      response = response << 1
      response += read_one_bit
    end
    return response
  end
end

#read_byte_as_binary(bytelen) ⇒ Object 



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# File 'lib/binary.rb', line 172

def read_byte_as_binary(bytelen)
  return read_bit_as_binary(bytelen*8)
end

#read_byte_as_integer(bytelen) ⇒ Object

Read specified length of bytes and return as Integer instance. Bit pointer proceed for that length.



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# File 'lib/binary.rb', line 119

def read_byte_as_integer(bytelen)
  unless bit_pointer % 8 == 0
    raise BinaryException.new("Bit pointer must be pointing start of byte. " +
                              "But now pointing #{bit_pointer}.")
  end
  if self.length - bit_pointer/8 < bytelen
    raise BinaryException.new("Rest of self length(#{self.length - bit_pointer/8}byte) " + 
                              "is shorter than specified byte length(#{bytelen}byte).")
  end
  response = 0
  bytelen.times do |i|
    response = response << 8
    response += to_i(bit_pointer/8 + i)
  end
  bit_pointer_inc(bytelen * 8)
  return response
end

#read_one_bit ⇒ Object

Read one bit and return as 0 or 1. Bit pointer proceed for one.



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# File 'lib/binary.rb', line 139

def read_one_bit
  unless self.length * 8 - bit_pointer > 0
    raise BinaryException.new("Readable buffer doesn't exist" +
                              "(#{self.length * 8 - bit_pointer}bit exists).")
  end
  response = to_i(bit_pointer/8)[7 - bit_pointer%8]
  bit_pointer_inc(1)
  return response
end

#readable? ⇒ Boolean

Return whether bit pointer reached end or not (true/false).

Returns:

  • (Boolean) 


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# File 'lib/binary.rb', line 181

def readable?
  return bit_pointer < self.length * 8
end

#rest_readable_bit_length ⇒ Object

Return length of rest readable bit



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# File 'lib/binary.rb', line 186

def rest_readable_bit_length
  return self.length * 8 - bit_pointer
end

#sub_integer(integer, bit_range) ⇒ Object

Get sub-bit of specified integer.

Example:

binary = Binary.new(something_byte_string)
binary.sub_integer(0b11111100, 1..2) # => 2 (0b10)



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# File 'lib/binary.rb', line 36

def sub_integer(integer, bit_range)
  bit_range = bit_range..bit_range if bit_range.kind_of?(Integer)
  num = 0
  bit_range.reverse_each do |i|
    num = num << 1
    num += integer[i]
  end
  return num
end

#to_i(byte_position) ⇒ Object

Return Integer that is converted from Byte at specified position.



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# File 'lib/binary.rb', line 47

def to_i(byte_position)
  return self[byte_position].unpack("C")[0]
end