Class: ActiveSupport::Multibyte::Chars

Inherits:
Object
  • Object
show all
Includes:
Comparable
Defined in:
lib/active_support/multibyte/chars.rb

Overview

Chars enables you to work transparently with UTF-8 encoding in the Ruby String class without having extensive knowledge about the encoding. A Chars object accepts a string upon initialization and proxies String methods in an encoding safe manner. All the normal String methods are also implemented on the proxy.

String methods are proxied through the Chars object, and can be accessed through the mb_chars method. Methods which would normally return a String object now return a Chars object so methods can be chained.

"The Perfect String  ".mb_chars.downcase.strip.normalize #=> "the perfect string"

Chars objects are perfectly interchangeable with String objects as long as no explicit class checks are made. If certain methods do explicitly check the class, call to_s before you pass chars objects to them.

bad.explicit_checking_method "T".mb_chars.downcase.to_s

The default Chars implementation assumes that the encoding of the string is UTF-8, if you want to handle different encodings you can write your own multibyte string handler and configure it through ActiveSupport::Multibyte.proxy_class.

class CharsForUTF32
  def size
    @wrapped_string.size / 4
  end

  def self.accepts?(string)
    string.length % 4 == 0
  end
end

ActiveSupport::Multibyte.proxy_class = CharsForUTF32

Constant Summary collapse

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
UNICODE_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
UNICODE_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.

UNICODE_WHITESPACE + [65279]
UNICODE_TRAILERS_PAT = 
/(#{codepoints_to_pattern(UNICODE_LEADERS_AND_TRAILERS)})+\Z/
UNICODE_LEADERS_PAT = 
/\A(#{codepoints_to_pattern(UNICODE_LEADERS_AND_TRAILERS)})+/
UTF8_PAT =

Borrowed from the Kconv library by Shinji KONO - (also as seen on the W3C site)

/\A(?:
 [\x00-\x7f]                                     |
 [\xc2-\xdf] [\x80-\xbf]                         |
 \xe0        [\xa0-\xbf] [\x80-\xbf]             |
 [\xe1-\xef] [\x80-\xbf] [\x80-\xbf]             |
 \xf0        [\x90-\xbf] [\x80-\xbf] [\x80-\xbf] |
 [\xf1-\xf3] [\x80-\xbf] [\x80-\xbf] [\x80-\xbf] |
 \xf4        [\x80-\x8f] [\x80-\xbf] [\x80-\xbf]
)*\z/xn

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(string) ⇒ Chars

:nodoc:



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# File 'lib/active_support/multibyte/chars.rb', line 93

def initialize(string)
  @wrapped_string = string
  @wrapped_string.force_encoding(Encoding::UTF_8) unless @wrapped_string.frozen?
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) ⇒ Object

Forward all undefined methods to the wrapped string.



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# File 'lib/active_support/multibyte/chars.rb', line 104

def method_missing(method, *args, &block)
  if method.to_s =~ /!$/
    @wrapped_string.__send__(method, *args, &block)
    self
  else
    result = @wrapped_string.__send__(method, *args, &block)
    result.kind_of?(String) ? chars(result) : result
  end
end

Instance Attribute Details

#wrapped_string ⇒ Object (readonly) Also known as: to_s, to_str

Returns the value of attribute wrapped_string.



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# File 'lib/active_support/multibyte/chars.rb', line 87

def wrapped_string
  @wrapped_string
end

Class Method Details

.codepoints_to_pattern(array_of_codepoints) ⇒ Object

Returns a regular expression pattern that matches the passed Unicode codepoints



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# File 'lib/active_support/multibyte/chars.rb', line 70

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

.compose_codepoints(codepoints) ⇒ Object

Compose decomposed characters to the composed form.



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# File 'lib/active_support/multibyte/chars.rb', line 571

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 = UCD.codepoints[current_char]
      if current.combining_class > previous_combining_class
        if ref = UCD.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

.consumes?(string) ⇒ Boolean

Returns true when the proxy class can handle the string. Returns false otherwise.

Returns:

  • (Boolean) 


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# File 'lib/active_support/multibyte/chars.rb', line 132

def self.consumes?(string)
  # Unpack is a little bit faster than regular expressions.
  string.unpack('U*')
  true
rescue ArgumentError
  false
end

.decompose_codepoints(type, codepoints) ⇒ Object

Decompose composed characters to the decomposed form.



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# File 'lib/active_support/multibyte/chars.rb', line 550

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 = UCD.codepoints[cp].decomp_mapping) and (!UCD.codepoints[cp].decomp_type || type == :compatability)
      decomposed.concat decompose_codepoints(type, ncp.dup)
    else
      decomposed << cp
    end
  end
end

.g_pack(unpacked) ⇒ Object

Reverse operation of g_unpack.

Example:

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



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# File 'lib/active_support/multibyte/chars.rb', line 521

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

.g_unpack(string) ⇒ Object

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

Example:

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



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# File 'lib/active_support/multibyte/chars.rb', line 487

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
        one = ( previous == UCD.boundary[:cr] and current == UCD.boundary[:lf] ) or
        # L X (L|V|LV|LVT)
        two = ( UCD.boundary[:l] === previous and in_char_class?(current, [:l,:v,:lv,:lvt]) ) or
        # (LV|V) X (V|T)
        three = ( in_char_class?(previous, [:lv,:v]) and in_char_class?(current, [:v,:t]) ) or
        # (LVT|T) X (T)
        four = ( in_char_class?(previous, [:lvt,:t]) and UCD.boundary[:t] === current ) or
        # X Extend
        five = (UCD.boundary[:extend] === current)
      )
    else
      unpacked << codepoints[marker..pos-1]
      marker = pos
    end
  end 
  unpacked
end

.in_char_class?(codepoint, classes) ⇒ Boolean

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.

Returns:

  • (Boolean) 


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# File 'lib/active_support/multibyte/chars.rb', line 478

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

.padding(padsize, padstr = ' ') ⇒ Object

:nodoc:



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# File 'lib/active_support/multibyte/chars.rb', line 525

def padding(padsize, padstr=' ') #:nodoc:
  if padsize != 0
    new(padstr * ((padsize / u_unpack(padstr).size) + 1)).slice(0, padsize)
  else
    ''
  end
end

.reorder_characters(codepoints) ⇒ Object

Re-order codepoints so the string becomes canonical.



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# File 'lib/active_support/multibyte/chars.rb', line 534

def reorder_characters(codepoints)
  length = codepoints.length- 1
  pos = 0
  while pos < length do
    cp1, cp2 = UCD.codepoints[codepoints[pos]], UCD.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

.tidy_bytes(string) ⇒ Object

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



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# File 'lib/active_support/multibyte/chars.rb', line 630

def tidy_bytes(string)
  string.split(//u).map do |c|
    c.force_encoding(Encoding::ASCII) if c.respond_to?(:force_encoding)

    if !UTF8_PAT.match(c)
      n = c.unpack('C')[0]
      n < 128 ? n.chr :
      n < 160 ? [UCD.cp1252[n] || n].pack('U') :
      n < 192 ? "\xC2" + n.chr : "\xC3" + (n-64).chr
    else
      c
    end
  end.join
end

.u_unpack(string) ⇒ Object

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

Example:

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



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# File 'lib/active_support/multibyte/chars.rb', line 465

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

.wants?(string) ⇒ Boolean

Returns true if the Chars class can and should act as a proxy for the string string. Returns false otherwise.

Returns:

  • (Boolean) 


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# File 'lib/active_support/multibyte/chars.rb', line 127

def self.wants?(string)
  $KCODE == 'UTF8' && consumes?(string)
end

Instance Method Details

#+(other) ⇒ Object

Returns a new Chars object containing the other object concatenated to the string.

Example:

('Café'.mb_chars + ' périferôl').to_s #=> "Café périferôl"



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# File 'lib/active_support/multibyte/chars.rb', line 156

def +(other)
  self << other
end

#<=>(other) ⇒ Object

Returns -1, 0 or +1 depending on whether the Chars object is to be sorted before, equal or after the object on the right side of the operation. It accepts any object that implements to_s. See String#<=> for more details.

Example:

'é'.mb_chars <=> 'ü'.mb_chars #=> -1



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# File 'lib/active_support/multibyte/chars.rb', line 148

def <=>(other)
  @wrapped_string <=> other.to_s
end

#=~(other) ⇒ Object

Like String#=~ only it returns the character offset (in codepoints) instead of the byte offset.

Example:

'Café périferôl'.mb_chars =~ /ô/ #=> 12



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# File 'lib/active_support/multibyte/chars.rb', line 164

def =~(other)
  translate_offset(@wrapped_string =~ other)
end

#[]=(*args) ⇒ Object

Like String#[]=, except instead of byte offsets you specify character offsets.

Example:

s = "Müller"
s.mb_chars[2] = "e" # Replace character with offset 2
s
#=> "Müeler"

s = "Müller"
s.mb_chars[1, 2] = "ö" # Replace 2 characters at character offset 1
s
#=> "Möler"



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# File 'lib/active_support/multibyte/chars.rb', line 225

def []=(*args)
  replace_by = args.pop
  # Indexed replace with regular expressions already works
  if args.first.is_a?(Regexp)
    @wrapped_string[*args] = replace_by
  else
    result = self.class.u_unpack(@wrapped_string)
    if args[0].is_a?(Fixnum)
      raise IndexError, "index #{args[0]} out of string" if args[0] >= result.length
      min = args[0]
      max = args[1].nil? ? min : (min + args[1] - 1)
      range = Range.new(min, max)
      replace_by = [replace_by].pack('U') if replace_by.is_a?(Fixnum)
    elsif args.first.is_a?(Range)
      raise RangeError, "#{args[0]} out of range" if args[0].min >= result.length
      range = args[0]
    else
      needle = args[0].to_s
      min = index(needle)
      max = min + self.class.u_unpack(needle).length - 1
      range = Range.new(min, max)
    end
    result[range] = self.class.u_unpack(replace_by)
    @wrapped_string.replace(result.pack('U*'))
  end
end

#acts_like_string? ⇒ Boolean

Enable more predictable duck-typing on String-like classes. See Object#acts_like?.

Returns:

  • (Boolean) 


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# File 'lib/active_support/multibyte/chars.rb', line 121

def acts_like_string?
  true
end

#capitalize ⇒ Object

Converts the first character to uppercase and the remainder to lowercase.

Example:

'über'.mb_chars.capitalize.to_s #=> "Über"



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# File 'lib/active_support/multibyte/chars.rb', line 387

def capitalize
  (slice(0) || chars('')).upcase + (slice(1..-1) || chars('')).downcase
end

#center(integer, padstr = ' ') ⇒ Object

Works just like String#center, only integer specifies characters instead of bytes.

Example:

"¾ cup".mb_chars.center(8).to_s
#=> " ¾ cup  "

"¾ cup".mb_chars.center(8, " ").to_s # Use non-breaking whitespace
#=> " ¾ cup  "



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# File 'lib/active_support/multibyte/chars.rb', line 287

def center(integer, padstr=' ')
  justify(integer, :center, padstr)
end

#compose ⇒ Object

Performs composition on all the characters.

Example:

'é'.length #=> 3
'é'.mb_chars.compose.to_s.length #=> 2



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# File 'lib/active_support/multibyte/chars.rb', line 429

def compose
  chars(self.class.compose_codepoints(self.class.u_unpack(@wrapped_string)).pack('U*'))
end

#decompose ⇒ Object

Performs canonical decomposition on all the characters.

Example:

'é'.length #=> 2
'é'.mb_chars.decompose.to_s.length #=> 3



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# File 'lib/active_support/multibyte/chars.rb', line 420

def decompose
  chars(self.class.decompose_codepoints(:canonical, self.class.u_unpack(@wrapped_string)).pack('U*'))
end

#downcase ⇒ Object

Convert characters in the string to lowercase.

Example:

'VĚDA A VÝZKUM'.mb_chars.downcase.to_s #=> "věda a výzkum"



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# File 'lib/active_support/multibyte/chars.rb', line 379

def downcase
  apply_mapping :lowercase_mapping
end

#g_length ⇒ Object

Returns the number of grapheme clusters in the string.

Example:

'क्षि'.mb_chars.length #=> 4
'क्षि'.mb_chars.g_length #=> 3



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# File 'lib/active_support/multibyte/chars.rb', line 438

def g_length
  self.class.g_unpack(@wrapped_string).length
end

#include?(other) ⇒ Boolean

Returns true if contained string contains other. Returns false otherwise.

Example:

'Café'.mb_chars.include?('é') #=> true

Returns:

  • (Boolean) 


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# File 'lib/active_support/multibyte/chars.rb', line 197

def include?(other)
  # We have to redefine this method because Enumerable defines it.
  @wrapped_string.include?(other)
end

#index(needle, offset = 0) ⇒ Object

Returns the position needle in the string, counting in codepoints. Returns nil if needle isn’t found.

Example:

'Café périferôl'.mb_chars.index('ô') #=> 12
'Café périferôl'.mb_chars.index(/\w/u) #=> 0



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# File 'lib/active_support/multibyte/chars.rb', line 207

def index(needle, offset=0)
  index = @wrapped_string.index(needle, offset)
  index ? (self.class.u_unpack(@wrapped_string.slice(0...index)).size) : nil
end

#insert(offset, fragment) ⇒ Object

Inserts the passed string at specified codepoint offsets.

Example:

'Café'.mb_chars.insert(4, ' périferôl').to_s #=> "Café périferôl"



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# File 'lib/active_support/multibyte/chars.rb', line 181

def insert(offset, fragment)
  unpacked = self.class.u_unpack(@wrapped_string)
  unless offset > unpacked.length
    @wrapped_string.replace(
      self.class.u_unpack(@wrapped_string).insert(offset, *self.class.u_unpack(fragment)).pack('U*')
    )
  else
    raise IndexError, "index #{offset} out of string"
  end
  self
end

#ljust(integer, padstr = ' ') ⇒ Object

Works just like String#ljust, only integer specifies characters instead of bytes.

Example:

"¾ cup".mb_chars.rjust(8).to_s
#=> "¾ cup   "

"¾ cup".mb_chars.rjust(8, " ").to_s # Use non-breaking whitespace
#=> "¾ cup   "



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# File 'lib/active_support/multibyte/chars.rb', line 274

def ljust(integer, padstr=' ')
  justify(integer, :left, padstr)
end

#lstrip ⇒ Object

Strips entire range of Unicode whitespace from the left of the string.



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# File 'lib/active_support/multibyte/chars.rb', line 297

def lstrip
  chars(@wrapped_string.gsub(UNICODE_LEADERS_PAT, ''))
end

#normalize(form = ActiveSupport::Multibyte.default_normalization_form) ⇒ Object

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

  • str - 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 ActiveSupport::Multibyte.default_normalization_form



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# File 'lib/active_support/multibyte/chars.rb', line 398

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

#ord ⇒ Object

Returns the codepoint of the first character in the string.

Example:

'こんにちは'.mb_chars.ord #=> 12371



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# File 'lib/active_support/multibyte/chars.rb', line 363

def ord
  self.class.u_unpack(@wrapped_string)[0]
end

#respond_to?(method, include_private = false) ⇒ Boolean

Returns true if obj responds to the given method. Private methods are included in the search only if the optional second parameter evaluates to true.

Returns:

  • (Boolean) 


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# File 'lib/active_support/multibyte/chars.rb', line 116

def respond_to?(method, include_private=false)
  super || @wrapped_string.respond_to?(method, include_private) || false
end

#reverse ⇒ Object

Reverses all characters in the string.

Example:

'Café'.mb_chars.reverse.to_s #=> 'éfaC'



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# File 'lib/active_support/multibyte/chars.rb', line 316

def reverse
  chars(self.class.u_unpack(@wrapped_string).reverse.pack('U*'))
end

#rjust(integer, padstr = ' ') ⇒ Object

Works just like String#rjust, only integer specifies characters instead of bytes.

Example:

"¾ cup".mb_chars.rjust(8).to_s
#=> "   ¾ cup"

"¾ cup".mb_chars.rjust(8, " ").to_s # Use non-breaking whitespace
#=> "   ¾ cup"



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# File 'lib/active_support/multibyte/chars.rb', line 261

def rjust(integer, padstr=' ')
  justify(integer, :right, padstr)
end

#rstrip ⇒ Object

Strips entire range of Unicode whitespace from the right of the string.



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# File 'lib/active_support/multibyte/chars.rb', line 292

def rstrip
  chars(@wrapped_string.gsub(UNICODE_TRAILERS_PAT, ''))
end

#size ⇒ Object Also known as: length

Returns the number of codepoints in the string



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# File 'lib/active_support/multibyte/chars.rb', line 307

def size
  self.class.u_unpack(@wrapped_string).size
end

#slice(*args) ⇒ Object Also known as: []

Implements Unicode-aware slice with codepoints. Slicing on one point returns the codepoints for that character.

Example:

'こんにちは'.mb_chars.slice(2..3).to_s #=> "にち"



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# File 'lib/active_support/multibyte/chars.rb', line 325

def slice(*args)
  if args.size > 2
    raise ArgumentError, "wrong number of arguments (#{args.size} for 1)" # Do as if we were native
  elsif (args.size == 2 && !(args.first.is_a?(Numeric) || args.first.is_a?(Regexp)))
    raise TypeError, "cannot convert #{args.first.class} into Integer" # Do as if we were native
  elsif (args.size == 2 && !args[1].is_a?(Numeric))
    raise TypeError, "cannot convert #{args[1].class} into Integer" # Do as if we were native
  elsif args[0].kind_of? Range
    cps = self.class.u_unpack(@wrapped_string).slice(*args)
    result = cps.nil? ? nil : cps.pack('U*')
  elsif args[0].kind_of? Regexp
    result = @wrapped_string.slice(*args)
  elsif args.size == 1 && args[0].kind_of?(Numeric)
    character = self.class.u_unpack(@wrapped_string)[args[0]]
    result = character.nil? ? nil : [character].pack('U')
  else
    result = self.class.u_unpack(@wrapped_string).slice(*args).pack('U*')
  end
  result.nil? ? nil : chars(result)
end

#slice!(*args) ⇒ Object

Like String#slice!, except instead of byte offsets you specify character offsets.

Example:

s = 'こんにちは'
s.mb_chars.slice!(2..3).to_s #=> "にち"
s #=> "こんは"



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# File 'lib/active_support/multibyte/chars.rb', line 353

def slice!(*args)
  slice = self[*args]
  self[*args] = ''
  slice
end

#split(*args) ⇒ Object

Works just like String#split, with the exception that the items in the resulting list are Chars instances instead of String. This makes chaining methods easier.

Example:

'Café périferôl'.mb_chars.split(/é/).map { |part| part.upcase.to_s } #=> ["CAF", " P", "RIFERÔL"]



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# File 'lib/active_support/multibyte/chars.rb', line 173

def split(*args)
  @wrapped_string.split(*args).map { |i| i.mb_chars }
end

#strip ⇒ Object

Strips entire range of Unicode whitespace from the right and left of the string.



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# File 'lib/active_support/multibyte/chars.rb', line 302

def strip
  rstrip.lstrip
end

#tidy_bytes ⇒ Object

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



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# File 'lib/active_support/multibyte/chars.rb', line 443

def tidy_bytes
  chars(self.class.tidy_bytes(@wrapped_string))
end

#upcase ⇒ Object

Convert characters in the string to uppercase.

Example:

'Laurent, òu sont les tests?'.mb_chars.upcase.to_s #=> "LAURENT, ÒU SONT LES TESTS?"



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# File 'lib/active_support/multibyte/chars.rb', line 371

def upcase
  apply_mapping :uppercase_mapping
end