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.


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# 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


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# 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


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

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