Class: Hash

Inherits:
Object
  • Object
show all
Defined in:
lib/hash-ber-tlv.rb

Instance Method Summary collapse

Instance Method Details

#from_ber_tlv(data) ⇒ Object 



2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
 
# File 'lib/hash-ber-tlv.rb', line 2

def from_ber_tlv(data)
	i = 0
	tag = data[i]
	if tag.unpack('C').pop & 0x1F == 0x1F # matches 00011111 mask? 
		begin
			i += 1
			tag[i] = data[i]
		end while tag[i].unpack('C').pop & 0x80 == 0x80
	end

	length = data[tag.length].unpack('C').pop

	tag_i = tag.unpack('H*').pop.to_i(16)

	if length < 0x80
		self[tag_i] = data[tag.length + 1, length]
		remainder = data[tag.length + 1 + length..-1]
	else
		num_octets = length & 0x7f
		octets = data[tag.length + 1, num_octets].unpack('C*')

		length = 0
 		octets.reverse.each_with_index {|octet, idx|
   		length += octet * (256**idx)
 		}

		self[tag_i] = data[tag.length + 1 + num_octets, length]
		remainder = data[tag.length + 1 + num_octets + length..-1]
	end

	if remainder and remainder.length > 2
		self.from_ber_tlv(remainder)
	end

	self
end

#int_to_binstr(i) ⇒ Object

converts integer to binary string representation



61
62
63
64
65
 
# File 'lib/hash-ber-tlv.rb', line 61

def int_to_binstr(i)
	binstr = "%X" % i
	binstr = '0' << binstr if binstr.size % 2 == 1
	[binstr].pack('H*')
end

#to_ber_tlv ⇒ Object 



39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
 
# File 'lib/hash-ber-tlv.rb', line 39

def to_ber_tlv
	result = ''.force_encoding('ASCII-8BIT')
	self.each do |tag, value|
	  v = value.dup.force_encoding('ASCII-8BIT')
		result << int_to_binstr(tag) # adding tag to result string

		#adding size of the tag
		if v.size < 0x80
			result << int_to_binstr(v.size)
		else
			len_len = int_to_binstr(v.size)
			result << int_to_binstr(0x80 | len_len.size)
			result << len_len
		end

		result << v
	end

	result
end