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# encoding: utf-8
require 'active_support/core_ext/string/access'
require 'active_support/core_ext/string/behavior'
module ActiveSupport #:nodoc:
module Multibyte #:nodoc:
# 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
class Chars
attr_reader :wrapped_string
alias to_s wrapped_string
alias to_str wrapped_string
if RUBY_VERSION >= "1.9"
# Creates a new Chars instance by wrapping _string_.
def initialize(string)
@wrapped_string = string
@wrapped_string.force_encoding(Encoding::UTF_8) unless @wrapped_string.frozen?
end
else
def initialize(string) #:nodoc:
@wrapped_string = string
end
end
# Forward all undefined methods to the wrapped string.
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
# 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+.
def respond_to?(method, include_private=false)
super || @wrapped_string.respond_to?(method, include_private)
end
# Enable more predictable duck-typing on String-like classes. See Object#acts_like?.
def acts_like_string?
true
end
# Returns +true+ when the proxy class can handle the string. Returns +false+ otherwise.
def self.consumes?(string)
# Unpack is a little bit faster than regular expressions.
string.unpack('U*')
true
rescue ArgumentError
false
end
include Comparable
# 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 <tt>String#<=></tt> for more details.
def <=>(other)
@wrapped_string <=> other.to_s
end
if RUBY_VERSION < "1.9"
# Returns +true+ if the Chars class can and should act as a proxy for the string _string_. Returns
# +false+ otherwise.
def self.wants?(string)
$KCODE == 'UTF8' && consumes?(string)
end
# Returns a new Chars object containing the _other_ object concatenated to the string.
#
# Example:
# ('Café'.mb_chars + ' périferôl').to_s # => "Café périferôl"
def +(other)
chars(@wrapped_string + other)
end
# Like <tt>String#=~</tt> only it returns the character offset (in codepoints) instead of the byte offset.
#
# Example:
# 'Café périferôl'.mb_chars =~ /ô/ # => 12
def =~(other)
translate_offset(@wrapped_string =~ other)
end
# Inserts the passed string at specified codepoint offsets.
#
# Example:
# 'Café'.mb_chars.insert(4, ' périferôl').to_s # => "Café périferôl"
def insert(offset, fragment)
unpacked = Unicode.u_unpack(@wrapped_string)
unless offset > unpacked.length
@wrapped_string.replace(
Unicode.u_unpack(@wrapped_string).insert(offset, *Unicode.u_unpack(fragment)).pack('U*')
)
else
raise IndexError, "index #{offset} out of string"
end
self
end
# Returns +true+ if contained string contains _other_. Returns +false+ otherwise.
#
# Example:
# 'Café'.mb_chars.include?('é') # => true
def include?(other)
# We have to redefine this method because Enumerable defines it.
@wrapped_string.include?(other)
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
def index(needle, offset=0)
wrapped_offset = first(offset).wrapped_string.length
index = @wrapped_string.index(needle, wrapped_offset)
index ? (Unicode.u_unpack(@wrapped_string.slice(0...index)).size) : nil
end
# Returns the position _needle_ in the string, counting in
# codepoints, searching backward from _offset_ or the end of the
# string. Returns +nil+ if _needle_ isn't found.
#
# Example:
# 'Café périferôl'.mb_chars.rindex('é') # => 6
# 'Café périferôl'.mb_chars.rindex(/\w/u) # => 13
def rindex(needle, offset=nil)
offset ||= length
wrapped_offset = first(offset).wrapped_string.length
index = @wrapped_string.rindex(needle, wrapped_offset)
index ? (Unicode.u_unpack(@wrapped_string.slice(0...index)).size) : nil
end
# Returns the number of codepoints in the string
def size
Unicode.u_unpack(@wrapped_string).size
end
alias_method :length, :size
# Strips entire range of Unicode whitespace from the right of the string.
def rstrip
chars(@wrapped_string.gsub(Unicode::TRAILERS_PAT, ''))
end
# Strips entire range of Unicode whitespace from the left of the string.
def lstrip
chars(@wrapped_string.gsub(Unicode::LEADERS_PAT, ''))
end
# Strips entire range of Unicode whitespace from the right and left of the string.
def strip
rstrip.lstrip
end
# Returns the codepoint of the first character in the string.
#
# Example:
# 'こんにちは'.mb_chars.ord # => 12371
def ord
Unicode.u_unpack(@wrapped_string)[0]
end
# Works just like <tt>String#rjust</tt>, 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"
def rjust(integer, padstr=' ')
justify(integer, :right, padstr)
end
# Works just like <tt>String#ljust</tt>, 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   "
def ljust(integer, padstr=' ')
justify(integer, :left, padstr)
end
# Works just like <tt>String#center</tt>, 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  "
def center(integer, padstr=' ')
justify(integer, :center, padstr)
end
else
def =~(other)
@wrapped_string =~ other
end
end
# Works just like <tt>String#split</tt>, 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"]
def split(*args)
@wrapped_string.split(*args).map { |i| i.mb_chars }
end
# Like <tt>String#[]=</tt>, 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"
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)
case args.first
when 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)
when 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
# Reverses all characters in the string.
#
# Example:
# 'Café'.mb_chars.reverse.to_s # => 'éfaC'
def reverse
chars(Unicode.g_unpack(@wrapped_string).reverse.flatten.pack('U*'))
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"
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
alias_method :[], :slice
# 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:
# 'こんにちは'.mb_chars.limit(7).to_s # => "こん"
def limit(limit)
slice(0...translate_offset(limit))
end
# Convert characters in the string to uppercase.
#
# Example:
# 'Laurent, où sont les tests ?'.mb_chars.upcase.to_s # => "LAURENT, OÙ SONT LES TESTS ?"
def upcase
chars(Unicode.apply_mapping @wrapped_string, :uppercase_mapping)
end
# Convert characters in the string to lowercase.
#
# Example:
# 'VĚDA A VÝZKUM'.mb_chars.downcase.to_s # => "věda a výzkum"
def downcase
chars(Unicode.apply_mapping @wrapped_string, :lowercase_mapping)
end
# Converts the first character to uppercase and the remainder to lowercase.
#
# Example:
# 'über'.mb_chars.capitalize.to_s # => "Über"
def capitalize
(slice(0) || chars('')).upcase + (slice(1..-1) || chars('')).downcase
end
# Capitalizes the first letter of every word, when possible.
#
# Example:
# "ÉL QUE SE ENTERÓ".mb_chars.titleize # => "Él Que Se Enteró"
# "日本語".mb_chars.titleize # => "日本語"
def titleize
chars(downcase.to_s.gsub(/\b('?[\S])/u) { Unicode.apply_mapping $1, :uppercase_mapping })
end
alias_method :titlecase, :titleize
# Returns the KC normalization of the string by default. NFKC is considered the best normalization form for
# passing strings to databases and validations.
#
# * <tt>form</tt> - The form you want to normalize in. Should be one of the following:
# <tt>:c</tt>, <tt>:kc</tt>, <tt>:d</tt>, or <tt>:kd</tt>. Default is
# ActiveSupport::Multibyte::Unicode.default_normalization_form
def normalize(form = nil)
chars(Unicode.normalize(@wrapped_string, form))
end
# Performs canonical decomposition on all the characters.
#
# Example:
# 'é'.length # => 2
# 'é'.mb_chars.decompose.to_s.length # => 3
def decompose
chars(Unicode.decompose_codepoints(:canonical, Unicode.u_unpack(@wrapped_string)).pack('U*'))
end
# Performs composition on all the characters.
#
# Example:
# 'é'.length # => 3
# 'é'.mb_chars.compose.to_s.length # => 2
def compose
chars(Unicode.compose_codepoints(Unicode.u_unpack(@wrapped_string)).pack('U*'))
end
# Returns the number of grapheme clusters in the string.
#
# Example:
# 'क्षि'.mb_chars.length # => 4
# 'क्षि'.mb_chars.g_length # => 3
def g_length
Unicode.g_unpack(@wrapped_string).length
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.
def tidy_bytes(force = false)
chars(Unicode.tidy_bytes(@wrapped_string, force))
end
%w(capitalize downcase lstrip reverse rstrip slice strip tidy_bytes upcase).each do |method|
# Only define a corresponding bang method for methods defined in the proxy; On 1.9 the proxy will
# exclude lstrip!, rstrip! and strip! because they are already work as expected on multibyte strings.
if public_method_defined?(method)
define_method("#{method}!") do |*args|
@wrapped_string = send(args.nil? ? method : method, *args).to_s
self
end
end
end
protected
def translate_offset(byte_offset) #:nodoc:
return nil if byte_offset.nil?
return 0 if @wrapped_string == ''
if @wrapped_string.respond_to?(:force_encoding)
@wrapped_string = @wrapped_string.dup.force_encoding(Encoding::ASCII_8BIT)
end
begin
@wrapped_string[0...byte_offset].unpack('U*').length
rescue ArgumentError
byte_offset -= 1
retry
end
end
def justify(integer, way, padstr=' ') #:nodoc:
raise ArgumentError, "zero width padding" if padstr.length == 0
padsize = integer - size
padsize = padsize > 0 ? padsize : 0
case way
when :right
result = @wrapped_string.dup.insert(0, padding(padsize, padstr))
when :left
result = @wrapped_string.dup.insert(-1, padding(padsize, padstr))
when :center
lpad = padding((padsize / 2.0).floor, padstr)
rpad = padding((padsize / 2.0).ceil, padstr)
result = @wrapped_string.dup.insert(0, lpad).insert(-1, rpad)
end
chars(result)
end
def padding(padsize, padstr=' ') #:nodoc:
if padsize != 0
chars(padstr * ((padsize / Unicode.u_unpack(padstr).size) + 1)).slice(0, padsize)
else
''
end
end
def chars(string) #:nodoc:
self.class.new(string)
end
end
end
end
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