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# encoding: utf-8
module ActiveSupport #:nodoc:
module CoreExtensions #:nodoc:
module String #:nodoc:
# Implements multibyte methods for easier access to multibyte characters in a String instance.
module Multibyte
unless '1.9'.respond_to?(:force_encoding)
# +mb_chars+ is a multibyte safe proxy method for string methods.
#
# In Ruby 1.8 and older it creates and returns an instance of the ActiveSupport::Multibyte::Chars class which
# encapsulates the original string. A Unicode safe version of all the String methods are defined on this proxy
# class. If the proxy class doesn't respond to a certain method, it's forwarded to the encapsuled string.
#
# name = 'Claus Müller'
# name.reverse #=> "rell??M sualC"
# name.length #=> 13
#
# name.mb_chars.reverse.to_s #=> "rellüM sualC"
# name.mb_chars.length #=> 12
#
# In Ruby 1.9 and newer +mb_chars+ returns +self+ because String is (mostly) encoding aware so we don't need
# a proxy class any more. This means that +mb_chars+ makes it easier to write code that runs on multiple Ruby
# versions.
#
# == Method chaining
#
# All the methods on the Chars proxy which normally return a string will return a Chars object. This allows
# method chaining on the result of any of these methods.
#
# name.mb_chars.reverse.length #=> 12
#
# == Interoperability and configuration
#
# The Char object tries to be as interchangeable with String objects as possible: sorting and comparing between
# String and Char work like expected. The bang! methods change the internal string representation in the Chars
# object. Interoperability problems can be resolved easily with a +to_s+ call.
#
# For more information about the methods defined on the Chars proxy see ActiveSupport::Multibyte::Chars. For
# information about how to change the default Multibyte behaviour, see ActiveSupport::Multibyte.
def mb_chars
if ActiveSupport::Multibyte.proxy_class.wants?(self)
ActiveSupport::Multibyte.proxy_class.new(self)
else
self
end
end
# Returns true if the string has UTF-8 semantics (a String used for purely byte resources is unlikely to have
# them), returns false otherwise.
def is_utf8?
ActiveSupport::Multibyte::Chars.consumes?(self)
end
unless '1.8.7 and later'.respond_to?(:chars)
alias chars mb_chars
end
else
# In Ruby 1.9 and newer +mb_chars+ returns self. In Ruby 1.8 and older +mb_chars+ creates and returns an
# Unicode safe proxy for string operations, this makes it easier to write code that runs on multiple Ruby
# versions.
def mb_chars
self
end
# Returns true if the string has valid UTF-8 encoding.
def is_utf8?
case encoding
when Encoding::UTF_8
valid_encoding?
when Encoding::ASCII_8BIT, Encoding::US_ASCII
dup.force_encoding(Encoding::UTF_8).valid_encoding?
else
false
end
end
end
end
end
end
end
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