Method: Bytepack::Basic.bytesToInt

Defined in:
lib/bytepack/basic.rb

.bytesToInt(length, bytes, offset = 0) ⇒ Object

bytes = array of 8-bit unsigned



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# File 'lib/bytepack/basic.rb', line 20

def bytesToInt(length, bytes, offset = 0) # bytes = array of 8-bit unsigned
  format = "C#{length}"
  format.prepend("@#{offset}") if offset > 0
  bytes = bytes.unpack(format)
  most_significant_bit = 1 << 7
  negative = (bytes[0] & most_significant_bit) != 0
  unscaled_value = -(bytes[0] & most_significant_bit) << length*8-8
  # Clear the highest bit
  # Unleash the powers of the butterfly
  bytes[0] &= ~most_significant_bit
  # Get the 2's complement
  (0..length-1).each {|i| unscaled_value += bytes[i] << ((length-1 - i) * 8)}
  unscaled_value * -1 if negative
  unscaled_value
end