class Mail::Multibyte::Chars
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 Mail::Multibyte.proxy_class
.
class CharsForUTF32 def size @wrapped_string.size / 4 end def self.accepts?(string) string.length % 4 == 0 end end Mail::Multibyte.proxy_class = CharsForUTF32
Attributes
Public Class Methods
Source
# File lib/mail/multibyte/chars.rb, line 42 def initialize(string) @wrapped_string = string.dup @wrapped_string.force_encoding(Encoding::UTF_8) unless @wrapped_string.frozen? end
Creates a new Chars
instance by wrapping string.
Public Instance Methods
Source
# File lib/mail/multibyte/chars.rb, line 78 def <=>(other) @wrapped_string <=> other.to_s 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
:
'é'.mb_chars <=> 'ü'.mb_chars # => -1
See String#<=>
for more details.
Source
# File lib/mail/multibyte/chars.rb, line 82 def =~(other) @wrapped_string =~ other end
Source
# File lib/mail/multibyte/chars.rb, line 108 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 = Unicode.u_unpack(@wrapped_string) if args[0].is_a?(Integer) 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?(Integer) 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 + Unicode.u_unpack(needle).length - 1 range = Range.new(min, max) end result[range] = Unicode.u_unpack(replace_by) @wrapped_string.replace(result.pack('U*')) end 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"
Source
# File lib/mail/multibyte/chars.rb, line 65 def acts_like_string? true end
Enable more predictable duck-typing on String-like classes. See Object#acts_like?.
Source
# File lib/mail/multibyte/chars.rb, line 201 def capitalize (slice(0) || chars('')).upcase + (slice(1..-1) || chars('')).downcase end
Converts the first character to uppercase and the remainder to lowercase.
Example:
Mail::Multibyte.mb_chars('über').capitalize.to_s # => "Über"
Source
# File lib/mail/multibyte/chars.rb, line 239 def compose chars(Unicode.compose_codepoints(Unicode.u_unpack(@wrapped_string)).pack('U*')) end
Performs composition on all the characters.
Example:
'é'.length # => 3 Mail::Multibyte.mb_chars('é').compose.to_s.length # => 2
Source
# File lib/mail/multibyte/chars.rb, line 230 def decompose chars(Unicode.decompose_codepoints(:canonical, Unicode.u_unpack(@wrapped_string)).pack('U*')) end
Performs canonical decomposition on all the characters.
Example:
'é'.length # => 2 Mail::Multibyte.mb_chars('é').decompose.to_s.length # => 3
Source
# File lib/mail/multibyte/chars.rb, line 193 def downcase chars(Unicode.apply_mapping(@wrapped_string, :lowercase_mapping)) end
Convert characters in the string to lowercase.
Example:
Mail::Multibyte.mb_chars('VĚDA A VÝZKUM').downcase.to_s # => "věda a výzkum"
Source
# File lib/mail/multibyte/chars.rb, line 248 def g_length Unicode.g_unpack(@wrapped_string).length end
Returns the number of grapheme clusters in the string.
Example:
Mail::Multibyte.mb_chars('क्षि').length # => 4 Mail::Multibyte.mb_chars('क्षि').g_length # => 3
Source
# File lib/mail/multibyte/chars.rb, line 177 def limit(limit) slice(0...translate_offset(limit)) end
Limit the byte size of the string to a number of bytes without breaking characters. Usable when the storage for a string is limited for some reason.
Example:
s = 'こんにちは' s.mb_chars.limit(7) # => "こん"
Source
# File lib/mail/multibyte/chars.rb, line 48 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
Forward all undefined methods to the wrapped string.
Source
# File lib/mail/multibyte/chars.rb, line 221 def normalize(form = nil) chars(Unicode.normalize(@wrapped_string, form)) end
Returns the KC normalization of the string by default. NFKC is considered the best normalization form for passing strings to databases and validations.
-
form
- The form you want to normalize in. Should be one of the following::c
,:kc
,:d
, or:kd
. Default isMail::Multibyte::Unicode.default_normalization_form
Source
# File lib/mail/multibyte/chars.rb, line 60 def respond_to?(method, include_private=false) super || @wrapped_string.respond_to?(method, include_private) || false 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
.
Source
# File lib/mail/multibyte/chars.rb, line 139 def reverse chars(Unicode.g_unpack(@wrapped_string).reverse.flatten.pack('U*')) end
Reverses all characters in the string.
Example:
Mail::Multibyte.mb_chars('Café').reverse.to_s # => 'éfaC'
Source
# File lib/mail/multibyte/chars.rb, line 148 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 = Unicode.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 = Unicode.u_unpack(@wrapped_string)[args[0]] result = character && [character].pack('U') else cps = Unicode.u_unpack(@wrapped_string).slice(*args) result = cps && cps.pack('U*') end result && chars(result) end
Implements Unicode-aware slice with codepoints. Slicing on one point returns the codepoints for that character.
Example:
Mail::Multibyte.mb_chars('こんにちは').slice(2..3).to_s # => "にち"
Source
# File lib/mail/multibyte/chars.rb, line 91 def split(*args) @wrapped_string.split(*args).map { |i| i.mb_chars } 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:
Mail::Multibyte.mb_chars('Café périferôl').split(/é/).map { |part| part.upcase.to_s } # => ["CAF", " P", "RIFERÔL"]
Source
# File lib/mail/multibyte/chars.rb, line 255 def tidy_bytes(force = false) chars(Unicode.tidy_bytes(@wrapped_string, force)) end
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.
Source
# File lib/mail/multibyte/chars.rb, line 210 def titleize chars(downcase.to_s.gsub(/\b('?\S)/u) { Unicode.apply_mapping $1, :uppercase_mapping }) end
Capitalizes the first letter of every word, when possible.
Example:
Mail::Multibyte.mb_chars("ÉL QUE SE ENTERÓ").titleize # => "Él Que Se Enteró" Mail::Multibyte.mb_chars("日本語").titleize # => "日本語"
Source
# File lib/mail/multibyte/chars.rb, line 185 def upcase chars(Unicode.apply_mapping(@wrapped_string, :uppercase_mapping)) end
Convert characters in the string to uppercase.
Example:
Mail::Multibyte.mb_chars('Laurent, où sont les tests ?').upcase.to_s # => "LAURENT, OÙ SONT LES TESTS ?"