class BitStream::String

Public Class Methods

instance(props, byte_len) click to toggle source
# File lib/types/string.rb, line 13
def self.instance(props, byte_len)
  new byte_len
end
new(byte_len) click to toggle source
# File lib/types/string.rb, line 17
def initialize(byte_len)
  @byte_len = byte_len
end

Public Instance Methods

length() click to toggle source
# File lib/types/string.rb, line 21
def length
  @byte_len * 8
end
read(s, offset) click to toggle source
# File lib/types/string.rb, line 25
def read(s, offset)
  bitoffset = offset % 8
  head = offset / 8
  tail = (offset + @byte_len * 8 + 7) / 8
  val = s[head...tail]
  Utils.bit_lshift(val, bitoffset)
  val.slice!(val.size - 1) if bitoffset != 0

  return FieldInfo.new(val, @byte_len * 8)
end
write(s, offset, data) click to toggle source
# File lib/types/string.rb, line 36
def write(s, offset, data)
  head = offset / 8
  tail = (offset + @byte_len * 8 + 7) / 8
  if offset % 8 != 0
    bitoffset = offset % 8
    Utils.bit_rshift(data, bitoffset)
    s[head] = ((data[0].ord & 0xff >> bitoffset) | (s[head].ord & 0xff << (8 - bitoffset))).chr
    s[tail - 1] = (data[data.size - 1].ord & 0xff << (8 - bitoffset)).chr
    s[(head + 1)..(tail - 2)] = data[1..(data.size - 2)]
  else
    s[head...tail] = data
  end
  return @byte_len * 8
end