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+package utf8;
+
+$utf8::hint_bits = 0x00800000;
+
+our $VERSION = '1.06';
+
+sub import {
+ $^H |= $utf8::hint_bits;
+ $enc{caller()} = $_[1] if $_[1];
+}
+
+sub unimport {
+ $^H &= ~$utf8::hint_bits;
+}
+
+sub AUTOLOAD {
+ require "utf8_heavy.pl";
+ goto &$AUTOLOAD if defined &$AUTOLOAD;
+ require Carp;
+ Carp::croak("Undefined subroutine $AUTOLOAD called");
+}
+
+1;
+__END__
+
+=head1 NAME
+
+utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code
+
+=head1 SYNOPSIS
+
+ use utf8;
+ no utf8;
+
+ # Convert a Perl scalar to/from UTF-8.
+ $num_octets = utf8::upgrade($string);
+ $success = utf8::downgrade($string[, FAIL_OK]);
+
+ # Change the native bytes of a Perl scalar to/from UTF-8 bytes.
+ utf8::encode($string);
+ utf8::decode($string);
+
+ $flag = utf8::is_utf8(STRING); # since Perl 5.8.1
+ $flag = utf8::valid(STRING);
+
+=head1 DESCRIPTION
+
+The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the
+program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based
+platforms). The C<no utf8> pragma tells Perl to switch back to treating
+the source text as literal bytes in the current lexical scope.
+
+This pragma is primarily a compatibility device. Perl versions
+earlier than 5.6 allowed arbitrary bytes in source code, whereas
+in future we would like to standardize on the UTF-8 encoding for
+source text.
+
+B<Do not use this pragma for anything else than telling Perl that your
+script is written in UTF-8.> The utility functions described below are
+useful for their own purposes, but they are not really part of the
+"pragmatic" effect.
+
+Until UTF-8 becomes the default format for source text, either this
+pragma or the L<encoding> pragma should be used to recognize UTF-8
+in the source. When UTF-8 becomes the standard source format, this
+pragma will effectively become a no-op. For convenience in what
+follows the term I<UTF-X> is used to refer to UTF-8 on ASCII and ISO
+Latin based platforms and UTF-EBCDIC on EBCDIC based platforms.
+
+See also the effects of the C<-C> switch and its cousin, the
+C<$ENV{PERL_UNICODE}>, in L<perlrun>.
+
+Enabling the C<utf8> pragma has the following effect:
+
+=over 4
+
+=item *
+
+Bytes in the source text that have their high-bit set will be treated
+as being part of a literal UTF-8 character. This includes most
+literals such as identifier names, string constants, and constant
+regular expression patterns.
+
+On EBCDIC platforms characters in the Latin 1 character set are
+treated as being part of a literal UTF-EBCDIC character.
+
+=back
+
+Note that if you have bytes with the eighth bit on in your script
+(for example embedded Latin-1 in your string literals), C<use utf8>
+will be unhappy since the bytes are most probably not well-formed
+UTF-8. If you want to have such bytes and use utf8, you can disable
+utf8 until the end the block (or file, if at top level) by C<no utf8;>.
+
+If you want to automatically upgrade your 8-bit legacy bytes to UTF-8,
+use the L<encoding> pragma instead of this pragma. For example, if
+you want to implicitly upgrade your ISO 8859-1 (Latin-1) bytes to UTF-8
+as used in e.g. C<chr()> and C<\x{...}>, try this:
+
+ use encoding "latin-1";
+ my $c = chr(0xc4);
+ my $x = "\x{c5}";
+
+In case you are wondering: yes, C<use encoding 'utf8';> works much
+the same as C<use utf8;>.
+
+=head2 Utility functions
+
+The following functions are defined in the C<utf8::> package by the
+Perl core. You do not need to say C<use utf8> to use these and in fact
+you should not say that unless you really want to have UTF-8 source code.
+
+=over 4
+
+=item * $num_octets = utf8::upgrade($string)
+
+Converts in-place the octet sequence in the native encoding
+(Latin-1 or EBCDIC) to the equivalent character sequence in I<UTF-X>.
+I<$string> already encoded as characters does no harm.
+Returns the number of octets necessary to represent the string as I<UTF-X>.
+Can be used to make sure that the UTF-8 flag is on,
+so that C<\w> or C<lc()> work as Unicode on strings
+containing characters in the range 0x80-0xFF (on ASCII and
+derivatives).
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore I<Encode.pm> is recommended for the general purposes.
+
+Affected by the encoding pragma.
+
+=item * $success = utf8::downgrade($string[, FAIL_OK])
+
+Converts in-place the character sequence in I<UTF-X>
+to the equivalent octet sequence in the native encoding (Latin-1 or EBCDIC).
+I<$string> already encoded as octets does no harm.
+Returns true on success. On failure dies or, if the value of
+C<FAIL_OK> is true, returns false.
+Can be used to make sure that the UTF-8 flag is off,
+e.g. when you want to make sure that the substr() or length() function
+works with the usually faster byte algorithm.
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore I<Encode.pm> is recommended for the general purposes.
+
+B<Not> affected by the encoding pragma.
+
+B<NOTE:> this function is experimental and may change
+or be removed without notice.
+
+=item * utf8::encode($string)
+
+Converts in-place the character sequence to the corresponding octet sequence
+in I<UTF-X>. The UTF-8 flag is turned off. Returns nothing.
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore I<Encode.pm> is recommended for the general purposes.
+
+=item * utf8::decode($string)
+
+Attempts to convert in-place the octet sequence in I<UTF-X>
+to the corresponding character sequence. The UTF-8 flag is turned on
+only if the source string contains multiple-byte I<UTF-X> characters.
+If I<$string> is invalid as I<UTF-X>, returns false; otherwise returns true.
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore I<Encode.pm> is recommended for the general purposes.
+
+B<NOTE:> this function is experimental and may change
+or be removed without notice.
+
+=item * $flag = utf8::is_utf8(STRING)
+
+(Since Perl 5.8.1) Test whether STRING is in UTF-8. Functionally
+the same as Encode::is_utf8().
+
+=item * $flag = utf8::valid(STRING)
+
+[INTERNAL] Test whether STRING is in a consistent state regarding
+UTF-8. Will return true is well-formed UTF-8 and has the UTF-8 flag
+on B<or> if string is held as bytes (both these states are 'consistent').
+Main reason for this routine is to allow Perl's testsuite to check
+that operations have left strings in a consistent state. You most
+probably want to use utf8::is_utf8() instead.
+
+=back
+
+C<utf8::encode> is like C<utf8::upgrade>, but the UTF8 flag is
+cleared. See L<perlunicode> for more on the UTF8 flag and the C API
+functions C<sv_utf8_upgrade>, C<sv_utf8_downgrade>, C<sv_utf8_encode>,
+and C<sv_utf8_decode>, which are wrapped by the Perl functions
+C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and
+C<utf8::decode>. Note that in the Perl 5.8.0 and 5.8.1 implementation
+the functions utf8::is_utf8, utf8::valid, utf8::encode, utf8::decode,
+utf8::upgrade, and utf8::downgrade are always available, without a
+C<require utf8> statement-- this may change in future releases.
+
+=head1 BUGS
+
+One can have Unicode in identifier names, but not in package/class or
+subroutine names. While some limited functionality towards this does
+exist as of Perl 5.8.0, that is more accidental than designed; use of
+Unicode for the said purposes is unsupported.
+
+One reason of this unfinishedness is its (currently) inherent
+unportability: since both package names and subroutine names may need
+to be mapped to file and directory names, the Unicode capability of
+the filesystem becomes important-- and there unfortunately aren't
+portable answers.
+
+=head1 SEE ALSO
+
+L<perluniintro>, L<encoding>, L<perlrun>, L<bytes>, L<perlunicode>
+
+=cut