Module: BaseHangul

Defined in:
lib/basehangul.rb,
lib/basehangul/utils.rb,
lib/basehangul/version.rb

Overview

Human-readable binary encoding.

Defined Under Namespace

Modules: Utils, Version

Constant Summary collapse

REGEX_BASEHANGUL =

Regular expression for BaseHangul.

Regexp.new('^(?:[^빎빔빕빗흐]{4})*' \
'(?:[^빎빔빕빗흐]흐{3}|[^빎빔빕빗흐]{2}흐{2}|' \
'[^빎빔빕빗흐]{3}[빎빔빕빗흐])?$').freeze

Class Method Summary collapse

Class Method Details

.decode(str) ⇒ Object

Public: Decode BaseHangul string. Characters outside the BaseHangul are ignored.

str - A String encoded with BaseHangul.

Returns the String decoded binary.



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# File 'lib/basehangul.rb', line 48

def self.decode(str)
  indices = str.each_char.map { |ch| Utils.to_index(ch) }
  binary = indices.map do |index|
    case index
    when 0..1023    then index.to_s(2).rjust(10, '0')
    when 1024..1027 then (index - 1024).to_s(2).rjust(2, '0')
    end
  end.join
  binary = binary[0..-(binary.size % 8 + 1)]
  [binary].pack('B*')
end

.encode(bin) ⇒ Object

Public: Encode binary with BaseHangul.

bin - A String binary to encode.

Returns the String encoded hangul.



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# File 'lib/basehangul.rb', line 29

def self.encode(bin)
  chunks = Utils.chunks(bin.unpack('B*').first, 10)
  padding = ''
  last = chunks.last
  if last
    case last.size
    when 2       then chunks[-1] = '1' + last.rjust(10, '0')
    when 4, 6, 8 then padding = PADDING * (last.size / 2 - 1)
    end
  end
  chunks.map { |b| Utils.to_hangul(b.ljust(10, '0').to_i(2)) }.join + padding
end

.strict_decode(str) ⇒ Object

Public: Decode BaseHangul string.

str - A String encoded with BaseHangul.

Returns the String decoded binary. Raises ArgumentError if str is invalid BaseHangul.



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# File 'lib/basehangul.rb', line 66

def self.strict_decode(str)
  indices = []
  str.each_char do |ch|
    index = Utils.to_index(ch)
    fail ArgumentError, MSG_INVALID_CHAR if index.nil?
    indices << index
  end
  fail ArgumentError, MSG_INVALID_PADDING unless str =~ REGEX_BASEHANGUL
  binary = indices.map do |index|
    case index
    when 0..1023    then index.to_s(2).rjust(10, '0')
    when 1024..1027 then (index - 1024).to_s(2).rjust(2, '0')
    end
  end.join
  binary = binary[0..-(binary.size % 8 + 1)]
  [binary].pack('B*')
end