Class: String

Inherits:
Object
  • Object
show all
Defined in:
lib/rdf_context/string_hacks.rb

Constant Summary collapse

RDF_MAP =

private “Borrowed” from JSON utf8_to_json

{
  "\x0" => '\u0000',
  "\x1" => '\u0001',
  "\x2" => '\u0002',
  "\x3" => '\u0003',
  "\x4" => '\u0004',
  "\x5" => '\u0005',
  "\x6" => '\u0006',
  "\x7" => '\u0007',
  "\b"  =>  '\b',
  "\t"  =>  '\t',
  "\n"  =>  '\n',
  "\xb" => '\u000B',
  "\f"  =>  '\f',
  "\r"  =>  '\r',
  "\xe" => '\u000E',
  "\xf" => '\u000F',
  "\x10" => '\u0010',
  "\x11" => '\u0011',
  "\x12" => '\u0012',
  "\x13" => '\u0013',
  "\x14" => '\u0014',
  "\x15" => '\u0015',
  "\x16" => '\u0016',
  "\x17" => '\u0017',
  "\x18" => '\u0018',
  "\x19" => '\u0019',
  "\x1a" => '\u001A',
  "\x1b" => '\u001B',
  "\x1c" => '\u001C',
  "\x1d" => '\u001D',
  "\x1e" => '\u001E',
  "\x1f" => '\u001F',
  '"'   =>  '\"',
  '\\'  =>  '\\\\',
  '/'   =>  '/',
}
ESCAPE_RE = 
%r(
  [\xc2-\xdf][\x80-\xbf]    |
  [\xe0-\xef][\x80-\xbf]{2} |
  [\xf0-\xf4][\x80-\xbf]{3}
)nx
RDF_UNESCAPE_MAP =

Unescape characters in strings.

Hash.new { |h, k| h[k] = k.chr }
UNESCAPE_RE = 
%r((?:\\[\\bfnrt"/]|(?:\\u(?:[A-Fa-f\d]{4}))+|\\[\x20-\xff]))n

Instance Method Summary collapse

Instance Method Details

#rdf_escape ⇒ Object

Convert a UTF8 encoded Ruby string string to an escaped string, encoded with UTF16 big endian characters as U????, and return it.

\

Backslash

'

Single quote

"

Double quot

n

ASCII Linefeed

r

ASCII Carriage Return

t

ASCCII Horizontal Tab

uhhhh

character in BMP with Unicode value U+hhhh

U00hhhhhh

character in plane 1-16 with Unicode value U+hhhhhh



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# File 'lib/rdf_context/string_hacks.rb', line 67

def rdf_escape
  string = self + '' # XXX workaround: avoid buffer sharing
  string.gsub!(/["\\\/\x0-\x1f]/) { RDF_MAP[$&] }
  if defined?(::Encoding)
    string.force_encoding(Encoding::UTF_8)
    string.gsub!(ESCAPE_RE) { |c|
                    s = c.dump.sub(/\"\\u\{(.+)\}\"/, '\1').upcase
                    (s.length <= 4 ? "\\u0000"[0,6-s.length] : "\\U00000000"[0,10-s.length]) + s
                  }
    string.force_encoding(Encoding::ASCII_8BIT)
  else
    string.gsub!(ESCAPE_RE) { |c|
                    s = Iconv.new('utf-16be', 'utf-8').iconv(c).unpack('H*').first.upcase
                    "\\u" + s
                  }
  end
  string
end

#rdf_unescape ⇒ Object

Reverse operation of escape From JSON parser



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# File 'lib/rdf_context/string_hacks.rb', line 112

def rdf_unescape
  return '' if self.empty?
  string = self.gsub(UNESCAPE_RE) do |c|
    case c[1,1]
    when 'U'
      raise RdfException, "Long Unicode escapes no supported in Ruby 1.8" unless defined?(::Encoding)
      eval(c.sub(/\\U00(\h+)/, '"\u{\1}"'))
    when 'u'
      bytes = [c[2, 2].to_i(16), c[4, 2].to_i(16)]
      Iconv.new('utf-8', 'utf-16').iconv(bytes.pack("C*"))
    else
      RDF_UNESCAPE_MAP[c[1]]
    end
  end
  string.force_encoding(Encoding::UTF_8) if defined?(::Encoding)
  string
rescue Iconv::Failure => e
  raise RdfException, "Caught #{e.class}: #{e}"
end