Encoding

Returns the hash of available encoding alias and original encoding name.

Encoding.aliases
#=> {"BINARY"=>"ASCII-8BIT", "ASCII"=>"US-ASCII", "ANSI_X3.4-1986"=>"US-ASCII",
      "SJIS"=>"Shift_JIS", "eucJP"=>"EUC-JP", "CP932"=>"Windows-31J"}

 
               static VALUE
rb_enc_aliases(VALUE klass)
{
    VALUE aliases[2];
    aliases[0] = rb_hash_new();
    aliases[1] = rb_ary_new();
    st_foreach(enc_table.names, rb_enc_aliases_enc_i, (st_data_t)aliases);
    return aliases[0];
}
            

Checks the compatibility of two objects.

If the objects are both strings they are compatible when they are concatenatable. The encoding of the concatenated string will be returned if they are compatible, nil if they are not.

Encoding.compatible?("\xa1".force_encoding("iso-8859-1"), "b")
#=> #<Encoding:ISO-8859-1>

Encoding.compatible?(
  "\xa1".force_encoding("iso-8859-1"),
  "\xa1\xa1".force_encoding("euc-jp"))
#=> nil

If the objects are non-strings their encodings are compatible when they have an encoding and:

• Either encoding is US-ASCII compatible

• One of the encodings is a 7-bit encoding

 
               static VALUE
enc_compatible_p(VALUE klass, VALUE str1, VALUE str2)
{
    rb_encoding *enc;

    if (!enc_capable(str1)) return Qnil;
    if (!enc_capable(str2)) return Qnil;
    enc = rb_enc_compatible(str1, str2);
    if (!enc) return Qnil;
    return rb_enc_from_encoding(enc);
}
            

Returns default external encoding.

The default external encoding is used by default for strings created from the following locations:

• CSV

• File data read from disk

• SDBM

• StringIO

• Zlib::GzipReader

• Zlib::GzipWriter

• String#inspect

• Regexp#inspect

While strings created from these locations will have this encoding, the encoding may not be valid. Be sure to check String#valid_encoding?.

File data written to disk will be transcoded to the default external encoding when written.

The default external encoding is initialized by the locale or -E option.

 
               static VALUE
get_default_external(VALUE klass)
{
    return rb_enc_default_external();
}
            

Sets default external encoding. You should not set ::default_external in ruby code as strings created before changing the value may have a different encoding from strings created after the value was changed., instead you should use ruby -E to invoke ruby with the correct default_external.

See ::default_external for information on how the default external encoding is used.

 
               static VALUE
set_default_external(VALUE klass, VALUE encoding)
{
    rb_warning("setting Encoding.default_external");
    rb_enc_set_default_external(encoding);
    return encoding;
}
            

Returns default internal encoding. Strings will be transcoded to the default internal encoding in the following places if the default internal encoding is not nil:

• CSV

• Etc.sysconfdir and Etc.systmpdir

• File data read from disk

• File names from Dir

• Integer#chr

• String#inspect and Regexp#inspect

• Strings returned from Readline

• Strings returned from SDBM

• Time#zone

• Values from ENV

• Values in ARGV including $PROGRAM_NAME

Additionally String#encode and String#encode! use the default internal encoding if no encoding is given.

The script encoding (__ENCODING__), not ::default_internal, is used as the encoding of created strings.

::default_internal is initialized by the source file's internal_encoding or -E option.

 
               static VALUE
get_default_internal(VALUE klass)
{
    return rb_enc_default_internal();
}
            

Sets default internal encoding or removes default internal encoding when passed nil. You should not set ::default_internal in ruby code as strings created before changing the value may have a different encoding from strings created after the change. Instead you should use ruby -E to invoke ruby with the correct default_internal.

See ::default_internal for information on how the default internal encoding is used.

 
               static VALUE
set_default_internal(VALUE klass, VALUE encoding)
{
    rb_warning("setting Encoding.default_internal");
    rb_enc_set_default_internal(encoding);
    return encoding;
}
            

Search the encoding with specified name. name should be a string.

Encoding.find("US-ASCII")  #=> #<Encoding:US-ASCII>

Names which this method accept are encoding names and aliases including following special aliases

“external”

default external encoding

“internal”

default internal encoding

“locale”

locale encoding

“filesystem”

filesystem encoding

An ArgumentError is raised when no encoding with name. Only Encoding.find("internal") however returns nil when no encoding named “internal”, in other words, when Ruby has no default internal encoding.

 
               static VALUE
enc_find(VALUE klass, VALUE enc)
{
    int idx;
    if (is_obj_encoding(enc))
        return enc;
    idx = str_to_encindex(enc);
    if (idx == UNSPECIFIED_ENCODING) return Qnil;
    return rb_enc_from_encoding_index(idx);
}
            

Returns the list of loaded encodings.

Encoding.list
#=> [#<Encoding:ASCII-8BIT>, #<Encoding:UTF-8>,
      #<Encoding:ISO-2022-JP (dummy)>]

Encoding.find("US-ASCII")
#=> #<Encoding:US-ASCII>

Encoding.list
#=> [#<Encoding:ASCII-8BIT>, #<Encoding:UTF-8>,
      #<Encoding:US-ASCII>, #<Encoding:ISO-2022-JP (dummy)>]

 
               static VALUE
enc_list(VALUE klass)
{
    VALUE ary = rb_ary_new2(0);
    rb_ary_replace(ary, rb_encoding_list);
    return ary;
}
            

Returns the locale charmap name. It returns nil if no appropriate information.

Debian GNU/Linux
  LANG=C
    Encoding.locale_charmap  #=> "ANSI_X3.4-1968"
  LANG=ja_JP.EUC-JP
    Encoding.locale_charmap  #=> "EUC-JP"

SunOS 5
  LANG=C
    Encoding.locale_charmap  #=> "646"
  LANG=ja
    Encoding.locale_charmap  #=> "eucJP"

The result is highly platform dependent. So ::find may cause an error. If you need some encoding object even for unknown locale, ::find("locale") can be used.

 
               VALUE
rb_locale_charmap(VALUE klass)
{
#if NO_LOCALE_CHARMAP
    return rb_usascii_str_new_cstr("US-ASCII");
#else
    return locale_charmap(rb_usascii_str_new_cstr);
#endif
}
            

Returns the list of available encoding names.

Encoding.name_list
#=> ["US-ASCII", "ASCII-8BIT", "UTF-8",
      "ISO-8859-1", "Shift_JIS", "EUC-JP",
      "Windows-31J",
      "BINARY", "CP932", "eucJP"]

 
               static VALUE
rb_enc_name_list(VALUE klass)
{
    VALUE ary = rb_ary_new2(enc_table.names->num_entries);
    st_foreach(enc_table.names, rb_enc_name_list_i, (st_data_t)ary);
    return ary;
}
            

Returns whether ASCII-compatible or not.

Encoding::UTF_8.ascii_compatible?     #=> true
Encoding::UTF_16BE.ascii_compatible?  #=> false

 
               static VALUE
enc_ascii_compatible_p(VALUE enc)
{
    return rb_enc_asciicompat(must_encoding(enc)) ? Qtrue : Qfalse;
}
            

Returns true for dummy encodings. A dummy encoding is an encoding for which character handling is not properly implemented. It is used for stateful encodings.

Encoding::ISO_2022_JP.dummy?       #=> true
Encoding::UTF_8.dummy?             #=> false

 
               static VALUE
enc_dummy_p(VALUE enc)
{
    return ENC_DUMMY_P(must_encoding(enc)) ? Qtrue : Qfalse;
}
            

Returns a string which represents the encoding for programmers.

Encoding::UTF_8.inspect       #=> "#<Encoding:UTF-8>"
Encoding::ISO_2022_JP.inspect #=> "#<Encoding:ISO-2022-JP (dummy)>"

 
               static VALUE
enc_inspect(VALUE self)
{
    rb_encoding *enc;

    if (!is_data_encoding(self)) {
        not_encoding(self);
    }
    if (!(enc = DATA_PTR(self)) || rb_enc_from_index(rb_enc_to_index(enc)) != enc) {
        rb_raise(rb_eTypeError, "broken Encoding");
    }
    return rb_enc_sprintf(rb_usascii_encoding(),
                          "#<%"PRIsVALUE":%s%s%s>", rb_obj_class(self),
                          rb_enc_name(enc),
                          (ENC_DUMMY_P(enc) ? " (dummy)" : ""),
                          enc_autoload_p(enc) ? " (autoload)" : "");
}
            

Returns the name of the encoding.

Encoding::UTF_8.name      #=> "UTF-8"

 
               static VALUE
enc_name(VALUE self)
{
    return rb_fstring_cstr(rb_enc_name((rb_encoding*)DATA_PTR(self)));
}
            

Returns the list of name and aliases of the encoding.

Encoding::WINDOWS_31J.names  #=> ["Windows-31J", "CP932", "csWindows31J"]

 
               static VALUE
enc_names(VALUE self)
{
    VALUE args[2];

    args[0] = (VALUE)rb_to_encoding_index(self);
    args[1] = rb_ary_new2(0);
    st_foreach(enc_table.names, enc_names_i, (st_data_t)args);
    return args[1];
}
            

Returns a replicated encoding of enc whose name is name. The new encoding should have the same byte structure of enc. If name is used by another encoding, raise ArgumentError.

 
               static VALUE
enc_replicate(VALUE encoding, VALUE name)
{
    return rb_enc_from_encoding_index(
        rb_enc_replicate(StringValueCStr(name),
                         rb_to_encoding(encoding)));
}
            

Returns the name of the encoding.

Encoding::UTF_8.name      #=> "UTF-8"

 
               static VALUE
enc_name(VALUE self)
{
    return rb_fstring_cstr(rb_enc_name((rb_encoding*)DATA_PTR(self)));
}