Class: BitStream::String

Inherits:
Object
  • Object
show all
Defined in:
lib/types/string.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(byte_len) ⇒ String

Returns a new instance of String.



17
18
19
 
# File 'lib/types/string.rb', line 17

def initialize(byte_len)
  @byte_len = byte_len
end

Class Method Details

.instance(props, byte_len) ⇒ Object 



13
14
15
 
# File 'lib/types/string.rb', line 13

def self.instance(props, byte_len)
  new byte_len
end

Instance Method Details

#length ⇒ Object 



21
22
23
 
# File 'lib/types/string.rb', line 21

def length
  @byte_len * 8
end

#read(s, offset) ⇒ Object 



25
26
27
28
29
30
31
32
33
34
 
# 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) ⇒ Object 



36
37
38
39
40
41
42
43
44
45
46
47
48
49
 
# 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