package Encode;
use strict;
-our $VERSION = do { my @r = (q$Revision: 1.58 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r };
+our $VERSION = do { my @r = (q$Revision: 1.61 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r };
our $DEBUG = 0;
use XSLoader ();
XSLoader::load 'Encode';
require Exporter;
-our @ISA = qw(Exporter);
+use base qw/Exporter/;
# Public, encouraged API is exported by default
encodings find_encoding
);
-our @FB_FLAGS = qw(DIE_ON_ERR WARN_ON_ERR RETURN_ON_ERR LEAVE_SRC PERLQQ);
-our @FB_CONSTS = qw(FB_DEFAULT FB_QUIET FB_WARN FB_PERLQQ FB_CROAK);
+our @FB_FLAGS = qw(DIE_ON_ERR WARN_ON_ERR RETURN_ON_ERR LEAVE_SRC
+ PERLQQ HTMLCREF XMLCREF);
+our @FB_CONSTS = qw(FB_DEFAULT FB_CROAK FB_QUIET FB_WARN
+ FB_PERLQQ FB_HTMLCREF FB_XMLCREF);
our @EXPORT_OK =
(
package Encode::UTF_EBCDIC;
*name = sub{ shift->{'Name'} };
*new_sequence = sub{ return $_[0] };
+ *needs_lines = sub{ 0 };
+ *perlio_ok = sub {
+ eval{ require PerlIO::encoding };
+ return $@ ? 0 : 1;
+ };
*decode = sub{
my ($obj,$str,$chk) = @_;
my $res = '';
package Encode::Internal;
*name = sub{ shift->{'Name'} };
*new_sequence = sub{ return $_[0] };
+ *needs_lines = sub{ 0 };
+ *perlio_ok = sub {
+ eval{ require PerlIO::encoding };
+ return $@ ? 0 : 1;
+ };
*decode = sub{
my ($obj,$str,$chk) = @_;
utf8::upgrade($str);
package Encode::utf8;
*name = sub{ shift->{'Name'} };
*new_sequence = sub{ return $_[0] };
+ *needs_lines = sub{ 0 };
+ *perlio_ok = sub {
+ eval{ require PerlIO::encoding };
+ return $@ ? 0 : 1;
+ };
*decode = sub{
my ($obj,$octets,$chk) = @_;
my $str = Encode::decode_utf8($octets);
=head2 TERMINOLOGY
-=over 4
+=over 2
=item *
=head1 PERL ENCODING API
-=over 4
+=over 2
=item $octets = encode(ENCODING, $string[, CHECK])
For example, to convert (internally UTF-8 encoded) Unicode string to
iso-8859-1 (also known as Latin1),
- $octets = encode("iso-8859-1", $unicode);
+ $octets = encode("iso-8859-1", $utf8);
+
+B<CAVEAT>: When you C<$octets = encode("utf8", $utf8)>, then $octets
+B<ne> $utf8. Though they both contain the same data, the utf8 flag
+for $octets is B<always> off. When you encode anything, utf8 flag of
+the result is always off, even when it contains completely valid utf8
+string. See L</"The UTF-8 flag"> below.
=item $string = decode(ENCODING, $octets[, CHECK])
$utf8 = decode("iso-8859-1", $latin1);
-=item [$length =] from_to($string, FROM_ENCODING, TO_ENCODING [,CHECK])
+B<CAVEAT>: When you C<$utf8 = encode("utf8", $octets)>, then $utf8
+B<may not be equal to> $utf8. Though they both contain the same data,
+the utf8 flag for $utf8 is on unless $octets entirely conststs of
+ASCII data (or EBCDIC on EBCDIC machines). See L</"The UTF-8 flag">
+below.
-Converts B<in-place> data between two encodings.
-For example, to convert ISO-8859-1 data to UTF-8:
+=item [$length =] from_to($string, FROM_ENC, TO_ENC [, CHECK])
+
+Converts B<in-place> data between two encodings. For example, to
+convert ISO-8859-1 data to UTF-8:
- from_to($data, "iso-8859-1", "utf-8");
+ from_to($data, "iso-8859-1", "utf8");
and to convert it back:
- from_to($data, "utf-8", "iso-8859-1");
+ from_to($data, "utf8", "iso-8859-1");
Note that because the conversion happens in place, the data to be
converted cannot be a string constant; it must be a scalar variable.
from_to() returns the length of the converted string on success, undef
otherwise.
-=back
+B<CAVEAT>: The following operations look the same but not quite so;
+
+ from_to($data, "iso-8859-1", "utf8"); #1
+ $data = decode("iso-8859-1", $data); #2
-=head2 UTF-8 / utf8
+Both #1 and #2 makes $data consists of completely valid UTF-8 string
+but only #2 turns utf8 flag on. #1 is equivalent to
-The Unicode Consortium defines the UTF-8 transformation format as a
-way of encoding the entire Unicode repertoire as sequences of octets.
-This encoding is expected to become very widespread. Perl can use this
-form internally to represent strings, so conversions to and from this
-form are particularly efficient (as octets in memory do not have to
-change, just the meta-data that tells Perl how to treat them).
+ $data = encode("utf8", decode("iso-8859-1", $data));
-=over 4
+See L</"The UTF-8 flag"> below.
=item $octets = encode_utf8($string);
-The characters that comprise $string are encoded in Perl's superset of
-UTF-8 and the resulting octets are returned as a sequence of bytes. All
-possible characters have a UTF-8 representation so this function cannot
-fail.
+Equivalent to C<$octets = encode("utf8", $string);> The characters
+that comprise $string are encoded in Perl's superset of UTF-8 and the
+resulting octets are returned as a sequence of bytes. All possible
+characters have a UTF-8 representation so this function cannot fail.
+
=item $string = decode_utf8($octets [, CHECK]);
-The sequence of octets represented by $octets is decoded from UTF-8
-into a sequence of logical characters. Not all sequences of octets
-form valid UTF-8 encodings, so it is possible for this call to fail.
-For CHECK, see L</"Handling Malformed Data">.
+equivalent to C<$string = decode("utf8", $octets [, CHECK])>.
+decode_utf8($octets [, CHECK]); The sequence of octets represented by
+$octets is decoded from UTF-8 into a sequence of logical
+characters. Not all sequences of octets form valid UTF-8 encodings, so
+it is possible for this call to fail. For CHECK, see
+L</"Handling Malformed Data">.
=back
=head1 Handling Malformed Data
-=over 4
+=over 2
The I<CHECK> argument is used as follows. When you omit it,
the behaviour is the same as if you had passed a value of 0 for
If the data is supposed to be UTF-8, an optional lexical warning
(category utf8) is given.
-=item I<CHECK> = Encode::DIE_ON_ERROR (== 1)
+=item I<CHECK> = Encode::FB_CROAK ( == 1)
If I<CHECK> is 1, methods will die immediately with an error
message. Therefore, when I<CHECK> is set to 1, you should trap the
=item perlqq mode (I<CHECK> = Encode::FB_PERLQQ)
+=item HTML charref mode (I<CHECK> = Encode::FB_HTMLCREF)
+
+=item XML charref mode (I<CHECK> = Encode::FB_XMLCREF)
+
For encodings that are implemented by Encode::XS, CHECK ==
Encode::FB_PERLQQ turns (en|de)code into C<perlqq> fallback mode.
where I<xxxx> is the Unicode ID of the character that cannot be found
in the character repertoire of the encoding.
+HTML/XML character reference modes are about the same, in place of
+\x{I<xxxx>}, HTML uses &#I<1234>; where I<1234> is a decimal digit and
+XML uses &#xI<abcd>; where I<abcd> is the hexadecimal digit.
+
=item The bitmask
These modes are actually set via a bitmask. Here is how the FB_XX
RETURN_ON_ERR 0x0004 X X
LEAVE_SRC 0x0008
PERLQQ 0x0100 X
+ HTMLCREF 0x0200
+ XMLCREF 0x0400
=head2 Unimplemented fallback schemes
See L<Encode::Encoding> for more details.
-=head1 Messing with Perl's Internals
+=head1 The UTF-8 flag
+
+Before the introduction of utf8 support in perl, The C<eq> operator
+just compares internal data of the scalars. Now C<eq> means internal
+data equality AND I<the utf8 flag>. To explain why we made it so, I
+will quote page 402 of C<Programming Perl, 3rd ed.>
+
+=over 2
+
+=item Goal #1:
+
+Old byte-oriented programs should not spontaneously break on the old
+byte-oriented data they used to work on.
+
+=item Goal #2:
+
+Old byte-oriented programs should magically start working on the new
+character-oriented data when appropriate.
+
+=item Goal #3:
+
+Programs should run just as fast in the new character-oriented mode
+as in the old byte-oriented mode.
+
+=item Goal #4:
+
+Perl should remain one language, rather than forking into a
+byte-oriented Perl and a character-oriented Perl.
+
+=back
+
+Back when C<Programming Perl, 3rd ed.> was written, not even Perl 5.6.0
+was born and many features documented in the book remained
+unimplemented. Perl 5.8 hopefully correct this and the introduction
+of UTF-8 flag is one of them. You can think this perl notion of
+byte-oriented mode (utf8 flag off) and character-oriented mode (utf8
+flag on).
+
+Here is how Encode takes care of the utf8 flag.
+
+=over2
+
+=item *
+
+When you encode, the resulting utf8 flag is always off.
+
+=item
+
+When you decode, the resuting utf8 flag is on unless you can
+unambiguously represent data. Here is the definition of
+dis-ambiguity.
+
+ After C<$utf8 = decode('foo', $octet);>,
+
+ When $octet is... The utf8 flag in $utf8 is
+ ---------------------------------------------
+ In ASCII only (or EBCDIC only) OFF
+ In ISO-8859-1 ON
+ In any other Encoding ON
+ ---------------------------------------------
+
+As you see, there is one exception, In ASCII. That way you can assue
+Goal #1. And with Encode Goal #2 is assumed but you still have to be
+careful in such cases mentioned in B<CAVEAT> paragraphs.
+
+This utf8 flag is not visible in perl scripts, exactly for the same
+reason you cannot (or you I<don't have to>) see if a scalar contains a
+string, integer, or floating point number. But you can still peek
+and poke these if you will. See the section below.
+
+=back
+
+=head2 Messing with Perl's Internals
The following API uses parts of Perl's internals in the current
implementation. As such, they are efficient but may change.
-=over 4
+=over 2
=item is_utf8(STRING [, CHECK])
=head1 MAINTAINER
This project was originated by Nick Ing-Simmons and later maintained
-by Dan Kogai E<lt>dankogai@dan.co.jpE<gt>. See AUTHORS for a full list
-of people involved. For any questions, use
-E<lt>perl-unicode@perl.orgE<gt> so others can share.
+by Dan Kogai E<lt>dankogai@dan.co.jpE<gt>. See AUTHORS for a full
+list of people involved. For any questions, use
+E<lt>perl-unicode@perl.orgE<gt> so we can all share share.
=cut
projects / p5sagit/p5-mst-13.2.git / blobdiff