Bug #5949 » 0001-encoding.c-add-documentation-introduction.patch
encoding.c | ||
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return aliases[0];
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}
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/*
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* An Encoding instance represents a character encoding usable in Ruby. It is
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* defined as a constant under the Encoding namespace. It has a name and
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* optionaly, aliases:
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*
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* Encoding::ISO_8859_1.name
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* #=> #<Encoding:ISO-8859-1>
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*
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* Encoding::ISO_8859_1.names
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* #=> ["ISO-8859-1", "ISO8859-1"]
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*
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* Ruby methods dealing with encodings return or take Encoding instances as
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* arguments (when a method accepts an Encoding instance as an argument, it can
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* be passed an Encoding name or alias instead).
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*
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* "some string".encoding
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* #=> #<Encoding:UTF-8>
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*
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* string = "some string".encode(Encoding::ISO_8859_1)
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* #=> "some string"
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* string.encoding
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* #=> #<Encoding:ISO-8859-1>
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*
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* "some string".encode("ISO-8859-1")
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* #=> "some string"
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*
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* <code>Encoding::ASCII_8BIT</code> is a special encoding that does not
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* correspond to any character encoding. In fact it represents the absence of
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* encoding and objects with this encoding can be seen as binary data.
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*
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* == Changing an encoding
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*
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* The associated Encoding of a String can can be changed in two different ways.
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*
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* First, it is possible to set the Encoding of a string to a new Encoding
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* without changing the internal byte representation of the string, with the
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* String#force_encoding method. This is how you can tell Ruby that another
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* encoding is better suited to treat the string.
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*
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* string
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* #=> "R\xC3\xA9sum\xC3\xA9"
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* string.encoding
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* #=> #<Encoding:ISO-8859-1>
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* string.force_encoding(Encoding:UTF-8)
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* #=> "Résumé"
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*
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* Second, it is possible to transcode a string, i.e. translate its internal
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* byte representation to another encoding. Its associated encoding is also
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* set to the other encoding. See String#encode for the various forms of
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* transcoding, and the Encoding::Converter class for additional control over
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* the transcoding process.
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*
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* string = "some string"
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* #=> "some string"
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* string.encoding
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* #=> #<Encoding:UTF-8>
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* string.encode!(Encoding::ISO_8859_1)
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* #=> "some string"
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* string.encoding
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* #=> #<Encoding:ISO-8859-1>
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*
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* == Locale encoding
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*
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* All Ruby source code has an associated Encoding which any String literal
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* created in the source code will be associated to.
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*
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* The default locale encoding is <code>Encoding::US-ASCII</code>, but it can
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* be changed by a magic comment on the first line of the source code file (or
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* second line, if there is a shebang line on the first). The comment must
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* contain the word <code>coding</code> or <code>encoding</code>, followed
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* by a colon, space and the Encoding name or alias:
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*
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* # encoding: UTF-8
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*
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* "some string".encoding
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* #=> #<Encoding:UTF-8>
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*
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* The <code>__ENCODING__</code> keyword returns the locale encoding that is
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* currently active:
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*
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* # encoding: ISO-8859-1
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*
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* __ENCODING__
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* #=> #<Encoding:ISO-8859-1>
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*
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* == External encoding
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*
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* Each IO object has an external encoding which indicates the encoding that
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* Ruby will use to read its data. By default Ruby sets the external
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* encoding of an IO object to the default external encoding (initialized from
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* the user's environment, set with the interpreter <code>-E</code> option or
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* the Encoding.default_external= method). Encoding.default_external returns
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* the current value of the external encoding.
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*
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* # Encoding.default_external
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* #=> #<Encoding:UTF-8>
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*
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* $ ruby -E ISO-8859-1 -e "p Encoding.default_external"
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* #<Encoding:ISO-8859-1>
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*
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* # Encoding.default_external = Encoding:ISO-8859-1
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* #=> #<Encoding:ISO-8859-1>
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* # Encoding.default_external
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* #=> #<Encoding:ISO-8859-1>
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*
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* When you know that the actual encoding of the data of an IO object is not
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* the default external encoding, you can reset its external encoding with
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* IO#set_encoding or set it at IO object creation (see IO.new options).
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*
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* == Internal encoding
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*
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* To process the data of an IO object which has an encoding different
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* from its external encoding, you can set its internal encoding. Ruby will use
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* this internal encoding to transcode the data when it is read from the IO
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* object.
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*
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* Conversely when data is written to the IO object, it is transcoded from the
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* internal encoding to the external encoding of the IO object.
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*
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* The internal encoding of an IO object can be set with
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* IO#set_encoding or at IO object creation (see IO.new options).
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*
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* The internal encoding is optional and when not set, the Ruby default
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* internal encoding is used. If not explicitly set this default internal
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* encoding is +nil+ meaning that by default, no transcoding occurs.
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*
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* The default internal encoding can be set with the interpreter option
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* <code>-E</code> or Encoding.default_internal=. Encoding.default_internal
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* returns the current value of the internal encoding.
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*
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* $ ruby -E ISO-8859-1:UTF-8 -e "p [Encoding.default_external, \
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Encoding.default_internal]"
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* [#<Encoding:ISO-8859-1>, #<Encoding:UTF-8>]
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*
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* # Encoding.default_internal
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* #=> nil
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* # Encoding.default_internal = Encoding::UTF_8
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* #=> #<Encoding:UTF-8>
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* # Encoding.default_internal
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* #=> #<Encoding:UTF-8>
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*
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*/
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void
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Init_Encoding(void)
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{
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