class Array

# File lib/core_ext.rb, line 36
def append_crc16
  append_uint(crc16, 2)
end

# File lib/core_ext.rb, line 22
def append_sint(number, byte)
  raise 'Insufficient bytes' if number.abs >= (1 << (byte * 8))

  sign = (number < 0) ? 1 : 0
  number &= (1 << ((byte * 8) - 1)) - 1
  self.append_uint(number, byte)
  self << (self.pop | (sign << 7))
end

# File lib/core_ext.rb, line 2
def append_uint(number, byte)
  raise 'Only support unsigned integer' if number < 0
  raise 'Insufficient bytes' if number.abs >= (1 << (byte * 8))

  until byte == 0
    self << (number & 0xFF)
    number >>= 8
    byte -= 1
  end
  self
end

# File lib/core_ext.rb, line 40
def check_crc16(remove_after_check = false)
  orig_crc = pop(2)
  old_crc = (orig_crc[1] << 8) + orig_crc[0]
  new_crc = crc16
  concat(orig_crc) unless remove_after_check
  old_crc == new_crc
end

# File lib/core_ext.rb, line 52
def to_bytehex
  map{|x| x.to_bytehex}
end

# File lib/core_ext.rb, line 31
def to_sint
  sign = (self.last & 0x80 != 0) ? (-1 ^ ((1 << ((self.size * 8) - 1)) - 1)) : 0
  sign | self.to_uint
end

# File lib/core_ext.rb, line 14
def to_uint
  int = 0
  self.each_with_index do |byte, index|
    int |= (byte << (index * 8))
  end
  int
end

# File lib/core_ext.rb, line 48
def xor(array2)
  zip(array2).map{|x, y| x ^ y }
end

# File lib/core_ext.rb, line 58
def crc16
  crc = 0x6363
  self.each do |byte|
    bb = (byte ^ crc) & 0xFF
    bb = (bb ^ (bb << 4)) & 0xFF
    crc = (crc >> 8) ^ (bb << 8) ^ (bb << 3) ^ (bb >> 4)
  end
  crc & 0xFFFF
end