Module: Mail::Multibyte::Unicode

Extended by:
Unicode
Included in:
Unicode
Defined in:
lib/mail/multibyte/unicode.rb

Defined Under Namespace

Classes: Codepoint, UnicodeDatabase

Constant Summary

NORMALIZATION_FORMS =

A list of all available normalization forms. See www.unicode.org/reports/tr15/tr15-29.html for more information about normalization.

[:c, :kc, :d, :kd]
UNICODE_VERSION =

The Unicode version that is supported by the implementation

'5.2.0'
HANGUL_SBASE =

Hangul character boundaries and properties

0xAC00
HANGUL_LBASE =
0x1100
HANGUL_VBASE =
0x1161
HANGUL_TBASE =
0x11A7
HANGUL_LCOUNT =
19
HANGUL_VCOUNT =
21
HANGUL_TCOUNT =
28
HANGUL_NCOUNT =
HANGUL_VCOUNT * HANGUL_TCOUNT
HANGUL_SCOUNT =
11172
HANGUL_SLAST =
HANGUL_SBASE + HANGUL_SCOUNT
HANGUL_JAMO_FIRST =
0x1100
HANGUL_JAMO_LAST =
0x11FF
WHITESPACE =

All the unicode whitespace

[
  (0x0009..0x000D).to_a, # White_Space # Cc   [5] <control-0009>..<control-000D>
  0x0020,                # White_Space # Zs       SPACE
  0x0085,                # White_Space # Cc       <control-0085>
  0x00A0,                # White_Space # Zs       NO-BREAK SPACE
  0x1680,                # White_Space # Zs       OGHAM SPACE MARK
  0x180E,                # White_Space # Zs       MONGOLIAN VOWEL SEPARATOR
  (0x2000..0x200A).to_a, # White_Space # Zs  [11] EN QUAD..HAIR SPACE
  0x2028,                # White_Space # Zl       LINE SEPARATOR
  0x2029,                # White_Space # Zp       PARAGRAPH SEPARATOR
  0x202F,                # White_Space # Zs       NARROW NO-BREAK SPACE
  0x205F,                # White_Space # Zs       MEDIUM MATHEMATICAL SPACE
  0x3000,                # White_Space # Zs       IDEOGRAPHIC SPACE
].flatten.freeze
LEADERS_AND_TRAILERS =

BOM (byte order mark) can also be seen as whitespace, it's a non-rendering character used to distinguish between little and big endian. This is not an issue in utf-8, so it must be ignored.

WHITESPACE + [65279]
TRAILERS_PAT =
/(#{codepoints_to_pattern(LEADERS_AND_TRAILERS)})+\Z/u
LEADERS_PAT =
/\A(#{codepoints_to_pattern(LEADERS_AND_TRAILERS)})+/u

Instance Attribute Summary (collapse)

Class Method Summary (collapse)

Instance Method Summary (collapse)

Instance Attribute Details

- (Object) default_normalization_form

The default normalization used for operations that require normalization. It can be set to any of the normalizations in NORMALIZATION_FORMS.

Example:

Mail::Multibyte::Unicode.default_normalization_form = :c


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# File 'lib/mail/multibyte/unicode.rb', line 19

def default_normalization_form
  @default_normalization_form
end

Class Method Details

+ (Object) codepoints_to_pattern(array_of_codepoints)

Returns a regular expression pattern that matches the passed Unicode codepoints



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# File 'lib/mail/multibyte/unicode.rb', line 57

def self.codepoints_to_pattern(array_of_codepoints) #:nodoc:
  array_of_codepoints.collect{ |e| [e].pack 'U*' }.join('|')
end

Instance Method Details

- (Object) apply_mapping(string, mapping)

:nodoc:



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# File 'lib/mail/multibyte/unicode.rb', line 300

def apply_mapping(string, mapping) #:nodoc:
  u_unpack(string).map do |codepoint|
    cp = database.codepoints[codepoint]
    if cp and (ncp = cp.send(mapping)) and ncp > 0
      ncp
    else
      codepoint
    end
  end.pack('U*')
end

- (Object) compose_codepoints(codepoints)

Compose decomposed characters to the composed form.



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# File 'lib/mail/multibyte/unicode.rb', line 166

def compose_codepoints(codepoints)
  pos = 0
  eoa = codepoints.length - 1
  starter_pos = 0
  starter_char = codepoints[0]
  previous_combining_class = -1
  while pos < eoa
    pos += 1
    lindex = starter_char - HANGUL_LBASE
    # -- Hangul
    if 0 <= lindex and lindex < HANGUL_LCOUNT
      vindex = codepoints[starter_pos+1] - HANGUL_VBASE rescue vindex = -1
      if 0 <= vindex and vindex < HANGUL_VCOUNT
        tindex = codepoints[starter_pos+2] - HANGUL_TBASE rescue tindex = -1
        if 0 <= tindex and tindex < HANGUL_TCOUNT
          j = starter_pos + 2
          eoa -= 2
        else
          tindex = 0
          j = starter_pos + 1
          eoa -= 1
        end
        codepoints[starter_pos..j] = (lindex * HANGUL_VCOUNT + vindex) * HANGUL_TCOUNT + tindex + HANGUL_SBASE
      end
      starter_pos += 1
      starter_char = codepoints[starter_pos]
    # -- Other characters
    else
      current_char = codepoints[pos]
      current = database.codepoints[current_char]
      if current.combining_class > previous_combining_class
        if ref = database.composition_map[starter_char]
          composition = ref[current_char]
        else
          composition = nil
        end
        unless composition.nil?
          codepoints[starter_pos] = composition
          starter_char = composition
          codepoints.delete_at pos
          eoa -= 1
          pos -= 1
          previous_combining_class = -1
        else
          previous_combining_class = current.combining_class
        end
      else
        previous_combining_class = current.combining_class
      end
      if current.combining_class == 0
        starter_pos = pos
        starter_char = codepoints[pos]
      end
    end
  end
  codepoints
end

- (Object) decompose_codepoints(type, codepoints)

Decompose composed characters to the decomposed form.



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# File 'lib/mail/multibyte/unicode.rb', line 145

def decompose_codepoints(type, codepoints)
  codepoints.inject([]) do |decomposed, cp|
    # if it's a hangul syllable starter character
    if HANGUL_SBASE <= cp and cp < HANGUL_SLAST
      sindex = cp - HANGUL_SBASE
      ncp = [] # new codepoints
      ncp << HANGUL_LBASE + sindex / HANGUL_NCOUNT
      ncp << HANGUL_VBASE + (sindex % HANGUL_NCOUNT) / HANGUL_TCOUNT
      tindex = sindex % HANGUL_TCOUNT
      ncp << (HANGUL_TBASE + tindex) unless tindex == 0
      decomposed.concat ncp
    # if the codepoint is decomposable in with the current decomposition type
    elsif (ncp = database.codepoints[cp].decomp_mapping) and (!database.codepoints[cp].decomp_type || type == :compatability)
      decomposed.concat decompose_codepoints(type, ncp.dup)
    else
      decomposed << cp
    end
  end
end

- (Object) g_pack(unpacked)

Reverse operation of g_unpack.

Example:

Unicode.g_pack(Unicode.g_unpack('क्षि')) # => 'क्षि'


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# File 'lib/mail/multibyte/unicode.rb', line 124

def g_pack(unpacked)
  (unpacked.flatten).pack('U*')
end

- (Object) g_unpack(string)

Unpack the string at grapheme boundaries. Returns a list of character lists.

Example:

Unicode.g_unpack('क्षि') # => [[2325, 2381], [2359], [2367]]
Unicode.g_unpack('Café') # => [[67], [97], [102], [233]]


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# File 'lib/mail/multibyte/unicode.rb', line 90

def g_unpack(string)
  codepoints = u_unpack(string)
  unpacked = []
  pos = 0
  marker = 0
  eoc = codepoints.length
  while(pos < eoc)
    pos += 1
    previous = codepoints[pos-1]
    current = codepoints[pos]
    if (
        # CR X LF
        ( previous == database.boundary[:cr] and current == database.boundary[:lf] ) or
        # L X (L|V|LV|LVT)
        ( database.boundary[:l] === previous and in_char_class?(current, [:l,:v,:lv,:lvt]) ) or
        # (LV|V) X (V|T)
        ( in_char_class?(previous, [:lv,:v]) and in_char_class?(current, [:v,:t]) ) or
        # (LVT|T) X (T)
        ( in_char_class?(previous, [:lvt,:t]) and database.boundary[:t] === current ) or
        # X Extend
        (database.boundary[:extend] === current)
      )
    else
      unpacked << codepoints[marker..pos-1]
      marker = pos
    end
  end
  unpacked
end

- (Boolean) in_char_class?(codepoint, classes)

Detect whether the codepoint is in a certain character class. Returns true when it's in the specified character class and false otherwise. Valid character classes are: :cr, :lf, :l, :v, :lv, :lvt and :t.

Primarily used by the grapheme cluster support.



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# File 'lib/mail/multibyte/unicode.rb', line 81

def in_char_class?(codepoint, classes)
  classes.detect { |c| database.boundary[c] === codepoint } ? true : false
end

- (Object) normalize(string, form = nil)

Returns the KC normalization of the string by default. NFKC is considered the best normalization form for passing strings to databases and validations.

  • string - The string to perform normalization on.

  • form - The form you want to normalize in. Should be one of the following: :c, :kc, :d, or :kd. Default is Mail::Multibyte.default_normalization_form



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# File 'lib/mail/multibyte/unicode.rb', line 282

def normalize(string, form=nil)
  form ||= @default_normalization_form
  # See http://www.unicode.org/reports/tr15, Table 1
  codepoints = u_unpack(string)
  case form
    when :d
      reorder_characters(decompose_codepoints(:canonical, codepoints))
    when :c
      compose_codepoints(reorder_characters(decompose_codepoints(:canonical, codepoints)))
    when :kd
      reorder_characters(decompose_codepoints(:compatability, codepoints))
    when :kc
      compose_codepoints(reorder_characters(decompose_codepoints(:compatability, codepoints)))
    else
      raise ArgumentError, "#{form} is not a valid normalization variant", caller
  end.pack('U*')
end

- (Object) reorder_characters(codepoints)

Re-order codepoints so the string becomes canonical.



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# File 'lib/mail/multibyte/unicode.rb', line 129

def reorder_characters(codepoints)
  length = codepoints.length- 1
  pos = 0
  while pos < length do
    cp1, cp2 = database.codepoints[codepoints[pos]], database.codepoints[codepoints[pos+1]]
    if (cp1.combining_class > cp2.combining_class) && (cp2.combining_class > 0)
      codepoints[pos..pos+1] = cp2.code, cp1.code
      pos += (pos > 0 ? -1 : 1)
    else
      pos += 1
    end
  end
  codepoints
end

- (Object) tidy_bytes(string, force = false)

Replaces all ISO-8859-1 or CP1252 characters by their UTF-8 equivalent resulting in a valid UTF-8 string.

Passing true will forcibly tidy all bytes, assuming that the string's encoding is entirely CP1252 or ISO-8859-1.



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# File 'lib/mail/multibyte/unicode.rb', line 227

def tidy_bytes(string, force = false)
  if force
    return string.unpack("C*").map do |b|
      tidy_byte(b)
    end.flatten.compact.pack("C*").unpack("U*").pack("U*")
  end

  bytes = string.unpack("C*")
  conts_expected = 0
  last_lead = 0

  bytes.each_index do |i|

    byte          = bytes[i]
    is_cont       = byte > 127 && byte < 192
    is_lead       = byte > 191 && byte < 245
    is_unused     = byte > 240
    is_restricted = byte > 244

    # Impossible or highly unlikely byte? Clean it.
    if is_unused || is_restricted
      bytes[i] = tidy_byte(byte)
    elsif is_cont
      # Not expecting contination byte? Clean up. Otherwise, now expect one less.
      conts_expected == 0 ? bytes[i] = tidy_byte(byte) : conts_expected -= 1
    else
      if conts_expected > 0
        # Expected continuation, but got ASCII or leading? Clean backwards up to
        # the leading byte.
        (1..(i - last_lead)).each {|j| bytes[i - j] = tidy_byte(bytes[i - j])}
        conts_expected = 0
      end
      if is_lead
        # Final byte is leading? Clean it.
        if i == bytes.length - 1
          bytes[i] = tidy_byte(bytes.last)
        else
          # Valid leading byte? Expect continuations determined by position of
          # first zero bit, with max of 3.
          conts_expected = byte < 224 ? 1 : byte < 240 ? 2 : 3
          last_lead = i
        end
      end
    end
  end
  bytes.empty? ? "" : bytes.flatten.compact.pack("C*").unpack("U*").pack("U*")
end

- (Object) u_unpack(string)

Unpack the string at codepoints boundaries. Raises an EncodingError when the encoding of the string isn't valid UTF-8.

Example:

Unicode.u_unpack('Café') # => [67, 97, 102, 233]


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# File 'lib/mail/multibyte/unicode.rb', line 68

def u_unpack(string)
  begin
    string.unpack 'U*'
  rescue ArgumentError
    raise EncodingError, 'malformed UTF-8 character'
  end
end