class OpenSSL::Config

def unescape_value(data, section, value)
  scanned = []
  while m = value.match(/['"\\$]/)
    scanned << m.pre_match
    c = m[0]
    value = m.post_match
    case c
    when "'"
      if m = value.match(QUOTE_REGEXP_SQ)
        scanned << m[1].gsub(/\\(.)/, '\\1')
        value = m.post_match
      else
        break
      end
    when '"'
      if m = value.match(QUOTE_REGEXP_DQ)
        scanned << m[1].gsub(/""/, '').gsub(/\\(.)/, '\\1')
        value = m.post_match
      else
        break
      end
    when "\\"
      c = value.slice!(0, 1)
      scanned << (ESCAPE_MAP[c] || c)
    when "$"
      ref, value = extract_reference(value)
      refsec = section
      if ref.index('::')
        refsec, ref = ref.split('::', 2)
      end
      if v = get_key_string(data, refsec, ref)
        scanned << v
      else
        raise ConfigError, "variable has no value"
      end
    else
      raise 'must not reaced'
    end
  end
  scanned << value
  scanned.join
end