Class | ActiveSupport::Multibyte::Chars |
In: |
vendor/rails/activesupport/lib/active_support/multibyte/chars.rb
|
Parent: | Object |
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
HANGUL_SBASE | = | 0xAC00 | Hangul character boundaries and properties | |
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 | = | [ (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 | All the unicode whitespace | |
UNICODE_LEADERS_AND_TRAILERS | = | UNICODE_WHITESPACE + [65279] | 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_TRAILERS_PAT | = | /(#{codepoints_to_pattern(UNICODE_LEADERS_AND_TRAILERS)})+\Z/ | ||
UNICODE_LEADERS_PAT | = | /\A(#{codepoints_to_pattern(UNICODE_LEADERS_AND_TRAILERS)})+/ | ||
UTF8_PAT | = | ActiveSupport::Multibyte::VALID_CHARACTER['UTF-8'] |
wrapped_string | -> | to_s |
wrapped_string | -> | to_str |
wrapped_string | [R] |
Compose decomposed characters to the composed form.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 550 550: def compose_codepoints(codepoints) 551: pos = 0 552: eoa = codepoints.length - 1 553: starter_pos = 0 554: starter_char = codepoints[0] 555: previous_combining_class = -1 556: while pos < eoa 557: pos += 1 558: lindex = starter_char - HANGUL_LBASE 559: # -- Hangul 560: if 0 <= lindex and lindex < HANGUL_LCOUNT 561: vindex = codepoints[starter_pos+1] - HANGUL_VBASE rescue vindex = -1 562: if 0 <= vindex and vindex < HANGUL_VCOUNT 563: tindex = codepoints[starter_pos+2] - HANGUL_TBASE rescue tindex = -1 564: if 0 <= tindex and tindex < HANGUL_TCOUNT 565: j = starter_pos + 2 566: eoa -= 2 567: else 568: tindex = 0 569: j = starter_pos + 1 570: eoa -= 1 571: end 572: codepoints[starter_pos..j] = (lindex * HANGUL_VCOUNT + vindex) * HANGUL_TCOUNT + tindex + HANGUL_SBASE 573: end 574: starter_pos += 1 575: starter_char = codepoints[starter_pos] 576: # -- Other characters 577: else 578: current_char = codepoints[pos] 579: current = UCD.codepoints[current_char] 580: if current.combining_class > previous_combining_class 581: if ref = UCD.composition_map[starter_char] 582: composition = ref[current_char] 583: else 584: composition = nil 585: end 586: unless composition.nil? 587: codepoints[starter_pos] = composition 588: starter_char = composition 589: codepoints.delete_at pos 590: eoa -= 1 591: pos -= 1 592: previous_combining_class = -1 593: else 594: previous_combining_class = current.combining_class 595: end 596: else 597: previous_combining_class = current.combining_class 598: end 599: if current.combining_class == 0 600: starter_pos = pos 601: starter_char = codepoints[pos] 602: end 603: end 604: end 605: codepoints 606: end
Returns true when the proxy class can handle the string. Returns false otherwise.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 123 123: def self.consumes?(string) 124: # Unpack is a little bit faster than regular expressions. 125: string.unpack('U*') 126: true 127: rescue ArgumentError 128: false 129: end
Decompose composed characters to the decomposed form.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 529 529: def decompose_codepoints(type, codepoints) 530: codepoints.inject([]) do |decomposed, cp| 531: # if it's a hangul syllable starter character 532: if HANGUL_SBASE <= cp and cp < HANGUL_SLAST 533: sindex = cp - HANGUL_SBASE 534: ncp = [] # new codepoints 535: ncp << HANGUL_LBASE + sindex / HANGUL_NCOUNT 536: ncp << HANGUL_VBASE + (sindex % HANGUL_NCOUNT) / HANGUL_TCOUNT 537: tindex = sindex % HANGUL_TCOUNT 538: ncp << (HANGUL_TBASE + tindex) unless tindex == 0 539: decomposed.concat ncp 540: # if the codepoint is decomposable in with the current decomposition type 541: elsif (ncp = UCD.codepoints[cp].decomp_mapping) and (!UCD.codepoints[cp].decomp_type || type == :compatability) 542: decomposed.concat decompose_codepoints(type, ncp.dup) 543: else 544: decomposed << cp 545: end 546: end 547: end
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]]
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 466 466: def g_unpack(string) 467: codepoints = u_unpack(string) 468: unpacked = [] 469: pos = 0 470: marker = 0 471: eoc = codepoints.length 472: while(pos < eoc) 473: pos += 1 474: previous = codepoints[pos-1] 475: current = codepoints[pos] 476: if ( 477: # CR X LF 478: one = ( previous == UCD.boundary[:cr] and current == UCD.boundary[:lf] ) or 479: # L X (L|V|LV|LVT) 480: two = ( UCD.boundary[:l] === previous and in_char_class?(current, [:l,:v,:lv,:lvt]) ) or 481: # (LV|V) X (V|T) 482: three = ( in_char_class?(previous, [:lv,:v]) and in_char_class?(current, [:v,:t]) ) or 483: # (LVT|T) X (T) 484: four = ( in_char_class?(previous, [:lvt,:t]) and UCD.boundary[:t] === current ) or 485: # X Extend 486: five = (UCD.boundary[:extend] === current) 487: ) 488: else 489: unpacked << codepoints[marker..pos-1] 490: marker = pos 491: end 492: end 493: unpacked 494: end
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.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 457 457: def in_char_class?(codepoint, classes) 458: classes.detect { |c| UCD.boundary[c] === codepoint } ? true : false 459: end
Re-order codepoints so the string becomes canonical.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 513 513: def reorder_characters(codepoints) 514: length = codepoints.length- 1 515: pos = 0 516: while pos < length do 517: cp1, cp2 = UCD.codepoints[codepoints[pos]], UCD.codepoints[codepoints[pos+1]] 518: if (cp1.combining_class > cp2.combining_class) && (cp2.combining_class > 0) 519: codepoints[pos..pos+1] = cp2.code, cp1.code 520: pos += (pos > 0 ? -1 : 1) 521: else 522: pos += 1 523: end 524: end 525: codepoints 526: end
Replaces all ISO-8859-1 or CP1252 characters by their UTF-8 equivalent resulting in a valid UTF-8 string.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 609 609: def tidy_bytes(string) 610: string.split(//u).map do |c| 611: c.force_encoding(Encoding::ASCII) if c.respond_to?(:force_encoding) 612: 613: if !ActiveSupport::Multibyte::VALID_CHARACTER['UTF-8'].match(c) 614: n = c.unpack('C')[0] 615: n < 128 ? n.chr : 616: n < 160 ? [UCD.cp1252[n] || n].pack('U') : 617: n < 192 ? "\xC2" + n.chr : "\xC3" + (n-64).chr 618: else 619: c 620: end 621: end.join 622: end
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]
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 444 444: def u_unpack(string) 445: begin 446: string.unpack 'U*' 447: rescue ArgumentError 448: raise EncodingError, 'malformed UTF-8 character' 449: end 450: end
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
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 139 139: def <=>(other) 140: @wrapped_string <=> other.to_s 141: end
Like String#=~ only it returns the character offset (in codepoints) instead of the byte offset.
Example:
'Café périferôl'.mb_chars =~ /ô/ #=> 12
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 155 155: def =~(other) 156: translate_offset(@wrapped_string =~ other) 157: end
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"
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 216 216: def []=(*args) 217: replace_by = args.pop 218: # Indexed replace with regular expressions already works 219: if args.first.is_a?(Regexp) 220: @wrapped_string[*args] = replace_by 221: else 222: result = self.class.u_unpack(@wrapped_string) 223: if args[0].is_a?(Fixnum) 224: raise IndexError, "index #{args[0]} out of string" if args[0] >= result.length 225: min = args[0] 226: max = args[1].nil? ? min : (min + args[1] - 1) 227: range = Range.new(min, max) 228: replace_by = [replace_by].pack('U') if replace_by.is_a?(Fixnum) 229: elsif args.first.is_a?(Range) 230: raise RangeError, "#{args[0]} out of range" if args[0].min >= result.length 231: range = args[0] 232: else 233: needle = args[0].to_s 234: min = index(needle) 235: max = min + self.class.u_unpack(needle).length - 1 236: range = Range.new(min, max) 237: end 238: result[range] = self.class.u_unpack(replace_by) 239: @wrapped_string.replace(result.pack('U*')) 240: end 241: end
Enable more predictable duck-typing on String-like classes. See Object#acts_like?.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 112 112: def acts_like_string? 113: true 114: end
Converts the first character to uppercase and the remainder to lowercase.
Example:
'über'.mb_chars.capitalize.to_s #=> "Über"
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 366 366: def capitalize 367: (slice(0) || chars('')).upcase + (slice(1..-1) || chars('')).downcase 368: end
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 "
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 278 278: def center(integer, padstr=' ') 279: justify(integer, :center, padstr) 280: end
Performs composition on all the characters.
Example:
'é'.length #=> 3 'é'.mb_chars.compose.to_s.length #=> 2
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 408 408: def compose 409: chars(self.class.compose_codepoints(self.class.u_unpack(@wrapped_string)).pack('U*')) 410: end
Performs canonical decomposition on all the characters.
Example:
'é'.length #=> 2 'é'.mb_chars.decompose.to_s.length #=> 3
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 399 399: def decompose 400: chars(self.class.decompose_codepoints(:canonical, self.class.u_unpack(@wrapped_string)).pack('U*')) 401: end
Convert characters in the string to lowercase.
Example:
'VĚDA A VÝZKUM'.mb_chars.downcase.to_s #=> "věda a výzkum"
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 358 358: def downcase 359: apply_mapping :lowercase_mapping 360: end
Returns the number of grapheme clusters in the string.
Example:
'क्षि'.mb_chars.length #=> 4 'क्षि'.mb_chars.g_length #=> 3
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 417 417: def g_length 418: self.class.g_unpack(@wrapped_string).length 419: end
Returns true if contained string contains other. Returns false otherwise.
Example:
'Café'.mb_chars.include?('é') #=> true
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 188 188: def include?(other) 189: # We have to redefine this method because Enumerable defines it. 190: @wrapped_string.include?(other) 191: end
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
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 198 198: def index(needle, offset=0) 199: index = @wrapped_string.index(needle, offset) 200: index ? (self.class.u_unpack(@wrapped_string.slice(0...index)).size) : nil 201: end
Inserts the passed string at specified codepoint offsets.
Example:
'Café'.mb_chars.insert(4, ' périferôl').to_s #=> "Café périferôl"
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 172 172: def insert(offset, fragment) 173: unpacked = self.class.u_unpack(@wrapped_string) 174: unless offset > unpacked.length 175: @wrapped_string.replace( 176: self.class.u_unpack(@wrapped_string).insert(offset, *self.class.u_unpack(fragment)).pack('U*') 177: ) 178: else 179: raise IndexError, "index #{offset} out of string" 180: end 181: self 182: end
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 "
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 265 265: def ljust(integer, padstr=' ') 266: justify(integer, :left, padstr) 267: end
Strips entire range of Unicode whitespace from the left of the string.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 288 288: def lstrip 289: chars(@wrapped_string.gsub(UNICODE_LEADERS_PAT, '')) 290: end
Forward all undefined methods to the wrapped string.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 95 95: def method_missing(method, *args, &block) 96: if method.to_s =~ /!$/ 97: @wrapped_string.__send__(method, *args, &block) 98: self 99: else 100: result = @wrapped_string.__send__(method, *args, &block) 101: result.kind_of?(String) ? chars(result) : result 102: end 103: end
Returns the KC normalization of the string by default. NFKC is considered the best normalization form for passing strings to databases and validations.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 377 377: def normalize(form=ActiveSupport::Multibyte.default_normalization_form) 378: # See http://www.unicode.org/reports/tr15, Table 1 379: codepoints = self.class.u_unpack(@wrapped_string) 380: chars(case form 381: when :d 382: self.class.reorder_characters(self.class.decompose_codepoints(:canonical, codepoints)) 383: when :c 384: self.class.compose_codepoints(self.class.reorder_characters(self.class.decompose_codepoints(:canonical, codepoints))) 385: when :kd 386: self.class.reorder_characters(self.class.decompose_codepoints(:compatability, codepoints)) 387: when :kc 388: self.class.compose_codepoints(self.class.reorder_characters(self.class.decompose_codepoints(:compatability, codepoints))) 389: else 390: raise ArgumentError, "#{form} is not a valid normalization variant", caller 391: end.pack('U*')) 392: end
Converts first character in the string to Unicode value
Example:
'こんにちは'.mb_chars.ord #=> 12371
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 342 342: def ord 343: self.class.u_unpack(@wrapped_string)[0] 344: end
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.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 107 107: def respond_to?(method, include_private=false) 108: super || @wrapped_string.respond_to?(method, include_private) || false 109: end
Reverses all characters in the string.
Example:
'Café'.mb_chars.reverse.to_s #=> 'éfaC'
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 307 307: def reverse 308: chars(self.class.u_unpack(@wrapped_string).reverse.pack('U*')) 309: end
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"
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 252 252: def rjust(integer, padstr=' ') 253: justify(integer, :right, padstr) 254: end
Strips entire range of Unicode whitespace from the right of the string.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 283 283: def rstrip 284: chars(@wrapped_string.gsub(UNICODE_TRAILERS_PAT, '')) 285: end
Returns the number of codepoints in the string
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 298 298: def size 299: self.class.u_unpack(@wrapped_string).size 300: end
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"
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 316 316: def slice(*args) 317: if args.size > 2 318: raise ArgumentError, "wrong number of arguments (#{args.size} for 1)" # Do as if we were native 319: elsif (args.size == 2 && !(args.first.is_a?(Numeric) || args.first.is_a?(Regexp))) 320: raise TypeError, "cannot convert #{args.first.class} into Integer" # Do as if we were native 321: elsif (args.size == 2 && !args[1].is_a?(Numeric)) 322: raise TypeError, "cannot convert #{args[1].class} into Integer" # Do as if we were native 323: elsif args[0].kind_of? Range 324: cps = self.class.u_unpack(@wrapped_string).slice(*args) 325: result = cps.nil? ? nil : cps.pack('U*') 326: elsif args[0].kind_of? Regexp 327: result = @wrapped_string.slice(*args) 328: elsif args.size == 1 && args[0].kind_of?(Numeric) 329: character = self.class.u_unpack(@wrapped_string)[args[0]] 330: result = character.nil? ? nil : [character].pack('U') 331: else 332: result = self.class.u_unpack(@wrapped_string).slice(*args).pack('U*') 333: end 334: result.nil? ? nil : chars(result) 335: end
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"]
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 164 164: def split(*args) 165: @wrapped_string.split(*args).map { |i| i.mb_chars } 166: end
Strips entire range of Unicode whitespace from the right and left of the string.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 293 293: def strip 294: rstrip.lstrip 295: end
Replaces all ISO-8859-1 or CP1252 characters by their UTF-8 equivalent resulting in a valid UTF-8 string.
# File vendor/rails/activesupport/lib/active_support/multibyte/chars.rb, line 422 422: def tidy_bytes 423: chars(self.class.tidy_bytes(@wrapped_string)) 424: end