Class: ANSEL::Converter

Inherits:
Object
  • Object
show all
Includes:
CharacterMap
Defined in:
lib/ansel/converter.rb

Constant Summary

Constants included from CharacterMap

ANSEL::CharacterMap::ANSI_TO_UTF16_MAP, ANSEL::CharacterMap::COMBINING, ANSEL::CharacterMap::NON_COMBINING

Instance Method Summary collapse

Constructor Details

#initialize(to_charset = 'UTF-8') ⇒ Converter

Returns a new instance of Converter.



7
8
9
10
 
# File 'lib/ansel/converter.rb', line 7

def initialize(to_charset = 'UTF-8')
  @to_charset = to_charset
  @encoding_converter = Encoding::Converter.new('UTF-16BE', 'UTF-8')
end

Instance Method Details

#convert(string) ⇒ Object 



16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
 
# File 'lib/ansel/converter.rb', line 16

def convert(string)
  output = ''
  scanner = StringScanner.new(string)
  until scanner.eos?
    byte = scanner.get_byte
    char = byte.unpack('C')[0]
    char_hex = char.to_s(16).upcase

    case char
    when 0x00..0x7F
      output << byte
    when 0x88..0xC8
      output << utf16_to_utf8(ANSI_TO_UTF16_MAP[char_hex] || ANSI_TO_UTF16_MAP['ERR'])
      last_byte = scanner.get_byte if scanner.check(/\00/)
    when 0xE0..0xFB
      [2, 1, 0].each do |n| # try 3 bytes, then 2 bytes, then 1 byte
        bytes = [char_hex]
        scanner.peek(n).each_byte { |b| bytes << b.to_s(16).upcase }
        hex_key = bytes.join('+')
        next unless ANSI_TO_UTF16_MAP.key?(hex_key)
        output << utf16_to_utf8(ANSI_TO_UTF16_MAP[hex_key])
        n.times { scanner.get_byte }
        break
      end
    else
      output << utf16_to_utf8(ANSI_TO_UTF16_MAP['ERR'])
      scanner.get_byte if scanner.get_byte.unpack('C')[0] >= 0xE0 # ignore the next byte
    end
  end

  output
end

#utf16_to_utf8(string) ⇒ Object 



12
13
14
 
# File 'lib/ansel/converter.rb', line 12

def utf16_to_utf8(string)
  @encoding_converter.convert(string)
end