Module: Tem::Apdus::Tag

Included in:
Session
Defined in:
lib/tem/apdus/tag.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.decode_tag(raw_data) ⇒ Object

Decodes raw TLV tag data into its structured form.

Args:

raw_data:: an array of bytes containing the raw data in the TEM tag

Returns a hash whose keys are numbers (tag keys), and whose values are arrays of bytes (values associated with the tag keys).



78
79
80
81
82
83
84
85
86
87
88
 
# File 'lib/tem/apdus/tag.rb', line 78

def self.decode_tag(raw_data)    
  data = {}
  index = 0
  while index < raw_data.length
    key = Tem::Abi.read_tem_ubyte raw_data, index
    value_length = Tem::Abi.read_tem_short raw_data, index + 1
    data[key] = raw_data[index + 3, value_length]
    index += 3 + value_length
  end
  data
end

.encode_tag(data) ⇒ Object

Encodes structured tag data into raw TLV tag data.

Args:

data:: a hash whose keys are numbers (tag keys), and whose values are
       arrays of bytes (values associated with the tag keys)

Returns an array of bytes with the raw data.



64
65
66
67
68
69
 
# File 'lib/tem/apdus/tag.rb', line 64

def self.encode_tag(data)
  data.keys.sort.map { |key|
    value = data[key]
    [Tem::Abi.to_tem_ubyte(key), Tem::Abi.to_tem_short(value.length), value]
  }.flatten
end

Instance Method Details

#get_raw_tag_data(offset, length) ⇒ Object

Reads raw bytes in the TEM’s tag.

Args:

offset:: the offset of the first byte to be read from the TEM's tag
length:: the number of bytes to be read from the TEM's tag.

Returns an array of bytes containing the requested TEM tag data.



44
45
46
47
48
49
50
51
52
53
54
55
 
# File 'lib/tem/apdus/tag.rb', line 44

def get_raw_tag_data(offset, length)
  buffer_id = alloc_buffer length
  begin
    @transport.iso_apdu! :ins => 0x32, :p1 => buffer_id,
                         :data => [to_tem_short(offset),
                                   to_tem_short(length)].flatten
    tag_data = read_buffer buffer_id
  ensure
    release_buffer buffer_id
  end
  tag_data
end

#get_raw_tag_length ⇒ Object

The number of bytes in the TEM’s tag.

This method issues an APDU when it’s called (i.e. no caching is done).



32
33
34
35
 
# File 'lib/tem/apdus/tag.rb', line 32

def get_raw_tag_length
  response = @transport.iso_apdu! :ins => 0x31
  return read_tem_short(response, 0)
end

#set_raw_tag_data(tag_data) ⇒ Object

Writes an array of bytes to the TEM’s tag.

The TEM’s tag can only be written once, when the TEM is emitted.

Args:

tag_data:: the array of bytes to write to the TEM's tag

The return value is unspecified.



20
21
22
23
24
25
26
27
 
# File 'lib/tem/apdus/tag.rb', line 20

def set_raw_tag_data(tag_data)    
  buffer_id = post_buffer tag_data
  begin
    @transport.iso_apdu! :ins => 0x30, :p1 => buffer_id
  ensure
    release_buffer buffer_id
  end
end

#set_tag(data) ⇒ Object

Writes an structured data to the TEM’s tag.

The TEM’s tag can only be written once, when the TEM is emitted.

Args:

tag_data:: the array of bytes to write to the TEM's tag

The return value is unspecified.



98
99
100
101
102
 
# File 'lib/tem/apdus/tag.rb', line 98

def set_tag(data)
  raw_data = Tem::Apdus::Tag.encode_tag data
  set_raw_tag_data raw_data
  icache[:tag] = Tem::Apdus::Tag.decode_tag raw_data
end

#tag ⇒ Object

The TEM’s tag data.

Returns a hash whose keys are numbers (tag keys), and whose values are arrays of bytes (values associated with the tag keys). The result of this method is cached.



109
110
111
112
113
114
 
# File 'lib/tem/apdus/tag.rb', line 109

def tag
  return icache[:tag] if icache[:tag]

  raw_tag_data = get_raw_tag_data 0, get_raw_tag_length
  icache[:tag] = Tem::Apdus::Tag.decode_tag raw_tag_data
end