2 # $Id: Encode.pm,v 1.84 2003/01/10 12:00:16 dankogai Exp dankogai $
6 our $VERSION = do { my @r = (q$Revision: 1.84 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r };
9 XSLoader::load(__PACKAGE__, $VERSION);
12 use base qw/Exporter/;
14 # Public, encouraged API is exported by default
17 decode decode_utf8 encode encode_utf8
18 encodings find_encoding
21 our @FB_FLAGS = qw(DIE_ON_ERR WARN_ON_ERR RETURN_ON_ERR LEAVE_SRC
22 PERLQQ HTMLCREF XMLCREF);
23 our @FB_CONSTS = qw(FB_DEFAULT FB_CROAK FB_QUIET FB_WARN
24 FB_PERLQQ FB_HTMLCREF FB_XMLCREF);
29 _utf8_off _utf8_on define_encoding from_to is_16bit is_8bit
30 is_utf8 perlio_ok resolve_alias utf8_downgrade utf8_upgrade
32 @FB_FLAGS, @FB_CONSTS,
37 all => [ @EXPORT, @EXPORT_OK ],
38 fallbacks => [ @FB_CONSTS ],
39 fallback_all => [ @FB_CONSTS, @FB_FLAGS ],
42 # Documentation moved after __END__ for speed - NI-S
44 our $ON_EBCDIC = (ord("A") == 193);
48 # Make a %Encoding package variable to allow a certain amount of cheating
51 require Encode::Config;
52 eval { require Encode::ConfigLocal };
58 if (@_ and $_[0] eq ":all"){
59 %enc = ( %Encoding, %ExtModule );
62 for my $mod (map {m/::/o ? $_ : "Encode::$_" } @_){
64 for my $enc (keys %ExtModule){
65 $ExtModule{$enc} eq $mod and $enc{$enc} = $mod;
70 sort { lc $a cmp lc $b }
71 grep {!/^(?:Internal|Unicode|Guess)$/o} keys %enc;
75 my $obj = ref($_[0]) ? $_[0] : find_encoding($_[0]);
76 $obj->can("perlio_ok") and return $obj->perlio_ok();
77 return 0; # safety net
84 $Encoding{$name} = $obj;
86 define_alias($lc => $obj) unless $lc eq $name;
89 define_alias($alias, $obj);
96 my ($class, $name, $skip_external) = @_;
98 ref($name) && $name->can('new_sequence') and return $name;
99 exists $Encoding{$name} and return $Encoding{$name};
101 exists $Encoding{$lc} and return $Encoding{$lc};
103 my $oc = $class->find_alias($name);
104 defined($oc) and return $oc;
105 $lc ne $name and $oc = $class->find_alias($lc);
106 defined($oc) and return $oc;
108 unless ($skip_external)
110 if (my $mod = $ExtModule{$name} || $ExtModule{$lc}){
111 $mod =~ s,::,/,g ; $mod .= '.pm';
112 eval{ require $mod; };
113 exists $Encoding{$name} and return $Encoding{$name};
121 my ($name, $skip_external) = @_;
122 return __PACKAGE__->getEncoding($name,$skip_external);
126 my $obj = find_encoding(shift);
127 defined $obj and return $obj->name;
133 my ($name, $string, $check) = @_;
134 return undef unless defined $string;
136 my $enc = find_encoding($name);
137 unless(defined $enc){
139 Carp::croak("Unknown encoding '$name'");
141 my $octets = $enc->encode($string,$check);
142 return undef if ($check && length($string));
148 my ($name,$octets,$check) = @_;
149 return undef unless defined $octets;
151 my $enc = find_encoding($name);
152 unless(defined $enc){
154 Carp::croak("Unknown encoding '$name'");
156 my $string = $enc->decode($octets,$check);
157 $_[1] = $octets if $check;
163 my ($string,$from,$to,$check) = @_;
164 return undef unless defined $string;
166 my $f = find_encoding($from);
169 Carp::croak("Unknown encoding '$from'");
171 my $t = find_encoding($to);
174 Carp::croak("Unknown encoding '$to'");
176 my $uni = $f->decode($string,$check);
177 return undef if ($check && length($string));
178 $string = $t->encode($uni,$check);
179 return undef if ($check && length($uni));
180 return defined($_[0] = $string) ? length($string) : undef ;
193 return undef unless utf8::decode($str);
197 predefine_encodings(1);
200 # This is to restore %Encoding if really needed;
203 sub predefine_encodings{
204 use Encode::Encoding;
205 no warnings 'redefine';
208 # was in Encode::UTF_EBCDIC
209 package Encode::UTF_EBCDIC;
210 push @Encode::UTF_EBCDIC::ISA, 'Encode::Encoding';
212 my ($obj,$str,$chk) = @_;
214 for (my $i = 0; $i < length($str); $i++) {
216 chr(utf8::unicode_to_native(ord(substr($str,$i,1))));
222 my ($obj,$str,$chk) = @_;
224 for (my $i = 0; $i < length($str); $i++) {
226 chr(utf8::native_to_unicode(ord(substr($str,$i,1))));
231 $Encode::Encoding{Unicode} =
232 bless {Name => "UTF_EBCDIC"} => "Encode::UTF_EBCDIC";
234 package Encode::Internal;
235 push @Encode::Internal::ISA, 'Encode::Encoding';
237 my ($obj,$str,$chk) = @_;
243 $Encode::Encoding{Unicode} =
244 bless {Name => "Internal"} => "Encode::Internal";
248 # was in Encode::utf8
249 package Encode::utf8;
250 push @Encode::utf8::ISA, 'Encode::Encoding';
253 $DEBUG and warn __PACKAGE__, " XS on";
254 *decode = \&decode_xs;
255 *encode = \&encode_xs;
257 $DEBUG and warn __PACKAGE__, " XS off";
259 my ($obj,$octets,$chk) = @_;
260 my $str = Encode::decode_utf8($octets);
268 my ($obj,$string,$chk) = @_;
269 my $octets = Encode::encode_utf8($string);
274 $Encode::Encoding{utf8} =
275 bless {Name => "utf8"} => "Encode::utf8";
285 Encode - character encodings
291 =head2 Table of Contents
293 Encode consists of a collection of modules whose details are too big
294 to fit in one document. This POD itself explains the top-level APIs
295 and general topics at a glance. For other topics and more details,
299 --------------------------------------------------------
300 Encode::Alias Alias definitions to encodings
301 Encode::Encoding Encode Implementation Base Class
302 Encode::Supported List of Supported Encodings
303 Encode::CN Simplified Chinese Encodings
304 Encode::JP Japanese Encodings
305 Encode::KR Korean Encodings
306 Encode::TW Traditional Chinese Encodings
307 --------------------------------------------------------
311 The C<Encode> module provides the interfaces between Perl's strings
312 and the rest of the system. Perl strings are sequences of
315 The repertoire of characters that Perl can represent is at least that
316 defined by the Unicode Consortium. On most platforms the ordinal
317 values of the characters (as returned by C<ord(ch)>) is the "Unicode
318 codepoint" for the character (the exceptions are those platforms where
319 the legacy encoding is some variant of EBCDIC rather than a super-set
320 of ASCII - see L<perlebcdic>).
322 Traditionally, computer data has been moved around in 8-bit chunks
323 often called "bytes". These chunks are also known as "octets" in
324 networking standards. Perl is widely used to manipulate data of many
325 types - not only strings of characters representing human or computer
326 languages but also "binary" data being the machine's representation of
327 numbers, pixels in an image - or just about anything.
329 When Perl is processing "binary data", the programmer wants Perl to
330 process "sequences of bytes". This is not a problem for Perl - as a
331 byte has 256 possible values, it easily fits in Perl's much larger
340 I<character>: a character in the range 0..(2**32-1) (or more).
341 (What Perl's strings are made of.)
345 I<byte>: a character in the range 0..255
346 (A special case of a Perl character.)
350 I<octet>: 8 bits of data, with ordinal values 0..255
351 (Term for bytes passed to or from a non-Perl context, e.g. a disk file.)
355 =head1 PERL ENCODING API
359 =item $octets = encode(ENCODING, $string [, CHECK])
361 Encodes a string from Perl's internal form into I<ENCODING> and returns
362 a sequence of octets. ENCODING can be either a canonical name or
363 an alias. For encoding names and aliases, see L</"Defining Aliases">.
364 For CHECK, see L</"Handling Malformed Data">.
366 For example, to convert a string from Perl's internal format to
367 iso-8859-1 (also known as Latin1),
369 $octets = encode("iso-8859-1", $string);
371 B<CAVEAT>: When you run C<$octets = encode("utf8", $string)>, then $octets
372 B<may not be equal to> $string. Though they both contain the same data, the utf8 flag
373 for $octets is B<always> off. When you encode anything, utf8 flag of
374 the result is always off, even when it contains completely valid utf8
375 string. See L</"The UTF-8 flag"> below.
377 encode($valid_encoding, undef) is harmless but warns you for
378 C<Use of uninitialized value in subroutine entry>.
379 encode($valid_encoding, '') is harmless and warnless.
381 =item $string = decode(ENCODING, $octets [, CHECK])
383 Decodes a sequence of octets assumed to be in I<ENCODING> into Perl's
384 internal form and returns the resulting string. As in encode(),
385 ENCODING can be either a canonical name or an alias. For encoding names
386 and aliases, see L</"Defining Aliases">. For CHECK, see
387 L</"Handling Malformed Data">.
389 For example, to convert ISO-8859-1 data to a string in Perl's internal format:
391 $string = decode("iso-8859-1", $octets);
393 B<CAVEAT>: When you run C<$string = decode("utf8", $octets)>, then $string
394 B<may not be equal to> $octets. Though they both contain the same data,
395 the utf8 flag for $string is on unless $octets entirely consists of
396 ASCII data (or EBCDIC on EBCDIC machines). See L</"The UTF-8 flag">
399 decode($valid_encoding, undef) is harmless but warns you for
400 C<Use of uninitialized value in subroutine entry>.
401 decode($valid_encoding, '') is harmless and warnless.
403 =item [$length =] from_to($octets, FROM_ENC, TO_ENC [, CHECK])
405 Converts B<in-place> data between two encodings. The data in $octets
406 must be encoded as octets and not as characters in Perl's internal
407 format. For example, to convert ISO-8859-1 data to Microsoft's CP1250 encoding:
409 from_to($octets, "iso-8859-1", "cp1250");
411 and to convert it back:
413 from_to($octets, "cp1250", "iso-8859-1");
415 Note that because the conversion happens in place, the data to be
416 converted cannot be a string constant; it must be a scalar variable.
418 from_to() returns the length of the converted string in octets on success, undef
421 B<CAVEAT>: The following operations look the same but are not quite so;
423 from_to($data, "iso-8859-1", "utf8"); #1
424 $data = decode("iso-8859-1", $data); #2
426 Both #1 and #2 make $data consist of a completely valid UTF-8 string
427 but only #2 turns utf8 flag on. #1 is equivalent to
429 $data = encode("utf8", decode("iso-8859-1", $data));
431 See L</"The UTF-8 flag"> below.
433 =item $octets = encode_utf8($string);
435 Equivalent to C<$octets = encode("utf8", $string);> The characters
436 that comprise $string are encoded in Perl's internal format and the
437 result is returned as a sequence of octets. All possible
438 characters have a UTF-8 representation so this function cannot fail.
441 =item $string = decode_utf8($octets [, CHECK]);
443 equivalent to C<$string = decode("utf8", $octets [, CHECK])>.
444 The sequence of octets represented by
445 $octets is decoded from UTF-8 into a sequence of logical
446 characters. Not all sequences of octets form valid UTF-8 encodings, so
447 it is possible for this call to fail. For CHECK, see
448 L</"Handling Malformed Data">.
452 =head2 Listing available encodings
455 @list = Encode->encodings();
457 Returns a list of the canonical names of the available encodings that
458 are loaded. To get a list of all available encodings including the
459 ones that are not loaded yet, say
461 @all_encodings = Encode->encodings(":all");
463 Or you can give the name of a specific module.
465 @with_jp = Encode->encodings("Encode::JP");
467 When "::" is not in the name, "Encode::" is assumed.
469 @ebcdic = Encode->encodings("EBCDIC");
471 To find out in detail which encodings are supported by this package,
472 see L<Encode::Supported>.
474 =head2 Defining Aliases
476 To add a new alias to a given encoding, use:
480 define_alias(newName => ENCODING);
482 After that, newName can be used as an alias for ENCODING.
483 ENCODING may be either the name of an encoding or an
486 But before you do so, make sure the alias is nonexistent with
487 C<resolve_alias()>, which returns the canonical name thereof.
490 Encode::resolve_alias("latin1") eq "iso-8859-1" # true
491 Encode::resolve_alias("iso-8859-12") # false; nonexistent
492 Encode::resolve_alias($name) eq $name # true if $name is canonical
494 resolve_alias() does not need C<use Encode::Alias>; it can be
495 exported via C<use Encode qw(resolve_alias)>.
497 See L<Encode::Alias> for details.
499 =head1 Encoding via PerlIO
501 If your perl supports I<PerlIO> (which is the default), you can use a PerlIO layer to decode
502 and encode directly via a filehandle. The following two examples
503 are totally identical in their functionality.
506 open my $in, "<:encoding(shiftjis)", $infile or die;
507 open my $out, ">:encoding(euc-jp)", $outfile or die;
508 while(<$in>){ print $out $_; }
511 open my $in, "<", $infile or die;
512 open my $out, ">", $outfile or die;
514 from_to($_, "shiftjis", "euc-jp", 1);
518 Unfortunately, it may be that encodings are PerlIO-savvy. You can check
519 if your encoding is supported by PerlIO by calling the C<perlio_ok>
522 Encode::perlio_ok("hz"); # False
523 find_encoding("euc-cn")->perlio_ok; # True where PerlIO is available
525 use Encode qw(perlio_ok); # exported upon request
528 Fortunately, all encodings that come with Encode core are PerlIO-savvy
529 except for hz and ISO-2022-kr. For gory details, see L<Encode::Encoding> and L<Encode::PerlIO>.
531 =head1 Handling Malformed Data
535 The I<CHECK> argument is used as follows. When you omit it,
536 the behaviour is the same as if you had passed a value of 0 for
539 =item I<CHECK> = Encode::FB_DEFAULT ( == 0)
541 If I<CHECK> is 0, (en|de)code will put a I<substitution character>
542 in place of a malformed character. For UCM-based encodings,
543 E<lt>subcharE<gt> will be used. For Unicode, the code point C<0xFFFD> is used.
544 If the data is supposed to be UTF-8, an optional lexical warning
545 (category utf8) is given.
547 =item I<CHECK> = Encode::FB_CROAK ( == 1)
549 If I<CHECK> is 1, methods will die on error immediately with an error
550 message. Therefore, when I<CHECK> is set to 1, you should trap the
551 fatal error with eval{} unless you really want to let it die on error.
553 =item I<CHECK> = Encode::FB_QUIET
555 If I<CHECK> is set to Encode::FB_QUIET, (en|de)code will immediately
556 return the portion of the data that has been processed so far when
557 an error occurs. The data argument will be overwritten with
558 everything after that point (that is, the unprocessed part of data).
559 This is handy when you have to call decode repeatedly in the case
560 where your source data may contain partial multi-byte character
561 sequences, for example because you are reading with a fixed-width
562 buffer. Here is some sample code that does exactly this:
564 my $data = ''; my $utf8 = '';
565 while(defined(read $fh, $buffer, 256)){
566 # buffer may end in a partial character so we append
568 $utf8 .= decode($encoding, $data, Encode::FB_QUIET);
569 # $data now contains the unprocessed partial character
572 =item I<CHECK> = Encode::FB_WARN
574 This is the same as above, except that it warns on error. Handy when
575 you are debugging the mode above.
577 =item perlqq mode (I<CHECK> = Encode::FB_PERLQQ)
579 =item HTML charref mode (I<CHECK> = Encode::FB_HTMLCREF)
581 =item XML charref mode (I<CHECK> = Encode::FB_XMLCREF)
583 For encodings that are implemented by Encode::XS, CHECK ==
584 Encode::FB_PERLQQ turns (en|de)code into C<perlqq> fallback mode.
586 When you decode, C<\xI<HH>> will be inserted for a malformed character,
587 where I<HH> is the hex representation of the octet that could not be
588 decoded to utf8. And when you encode, C<\x{I<HHHH>}> will be inserted,
589 where I<HHHH> is the Unicode ID of the character that cannot be found
590 in the character repertoire of the encoding.
592 HTML/XML character reference modes are about the same, in place of
593 C<\x{I<HHHH>}>, HTML uses C<&#I<NNNN>>; where I<NNNN> is a decimal digit and
594 XML uses C<&#xI<HHHH>>; where I<HHHH> is the hexadecimal digit.
598 These modes are actually set via a bitmask. Here is how the FB_XX
599 constants are laid out. You can import the FB_XX constants via
600 C<use Encode qw(:fallbacks)>; you can import the generic bitmask
601 constants via C<use Encode qw(:fallback_all)>.
603 FB_DEFAULT FB_CROAK FB_QUIET FB_WARN FB_PERLQQ
606 RETURN_ON_ERR 0x0004 X X
612 =head2 Unimplemented fallback schemes
614 In the future, you will be able to use a code reference to a callback
615 function for the value of I<CHECK> but its API is still undecided.
617 The fallback scheme does not work on EBCDIC platforms.
619 =head1 Defining Encodings
621 To define a new encoding, use:
623 use Encode qw(define_encoding);
624 define_encoding($object, 'canonicalName' [, alias...]);
626 I<canonicalName> will be associated with I<$object>. The object
627 should provide the interface described in L<Encode::Encoding>.
628 If more than two arguments are provided then additional
629 arguments are taken as aliases for I<$object>.
631 See L<Encode::Encoding> for more details.
633 =head1 The UTF-8 flag
635 Before the introduction of utf8 support in perl, The C<eq> operator
636 just compared the strings represented by two scalars. Beginning with
637 perl 5.8, C<eq> compares two strings with simultaneous consideration
638 of I<the utf8 flag>. To explain why we made it so, I will quote page
639 402 of C<Programming Perl, 3rd ed.>
645 Old byte-oriented programs should not spontaneously break on the old
646 byte-oriented data they used to work on.
650 Old byte-oriented programs should magically start working on the new
651 character-oriented data when appropriate.
655 Programs should run just as fast in the new character-oriented mode
656 as in the old byte-oriented mode.
660 Perl should remain one language, rather than forking into a
661 byte-oriented Perl and a character-oriented Perl.
665 Back when C<Programming Perl, 3rd ed.> was written, not even Perl 5.6.0
666 was born and many features documented in the book remained
667 unimplemented for a long time. Perl 5.8 corrected this and the introduction
668 of the UTF-8 flag is one of them. You can think of this perl notion as of a
669 byte-oriented mode (utf8 flag off) and a character-oriented mode (utf8
672 Here is how Encode takes care of the utf8 flag.
678 When you encode, the resulting utf8 flag is always off.
682 When you decode, the resulting utf8 flag is on unless you can
683 unambiguously represent data. Here is the definition of
686 After C<$utf8 = decode('foo', $octet);>,
688 When $octet is... The utf8 flag in $utf8 is
689 ---------------------------------------------
690 In ASCII only (or EBCDIC only) OFF
692 In any other Encoding ON
693 ---------------------------------------------
695 As you see, there is one exception, In ASCII. That way you can assue
696 Goal #1. And with Encode Goal #2 is assumed but you still have to be
697 careful in such cases mentioned in B<CAVEAT> paragraphs.
699 This utf8 flag is not visible in perl scripts, exactly for the same
700 reason you cannot (or you I<don't have to>) see if a scalar contains a
701 string, integer, or floating point number. But you can still peek
702 and poke these if you will. See the section below.
706 =head2 Messing with Perl's Internals
708 The following API uses parts of Perl's internals in the current
709 implementation. As such, they are efficient but may change.
713 =item is_utf8(STRING [, CHECK])
715 [INTERNAL] Tests whether the UTF-8 flag is turned on in the STRING.
716 If CHECK is true, also checks the data in STRING for being well-formed
717 UTF-8. Returns true if successful, false otherwise.
719 =item _utf8_on(STRING)
721 [INTERNAL] Turns on the UTF-8 flag in STRING. The data in STRING is
722 B<not> checked for being well-formed UTF-8. Do not use unless you
723 B<know> that the STRING is well-formed UTF-8. Returns the previous
724 state of the UTF-8 flag (so please don't treat the return value as
725 indicating success or failure), or C<undef> if STRING is not a string.
727 =item _utf8_off(STRING)
729 [INTERNAL] Turns off the UTF-8 flag in STRING. Do not use frivolously.
730 Returns the previous state of the UTF-8 flag (so please don't treat the
731 return value as indicating success or failure), or C<undef> if STRING is
739 L<Encode::Supported>,
746 the Perl Unicode Mailing List E<lt>perl-unicode@perl.orgE<gt>
750 This project was originated by Nick Ing-Simmons and later maintained
751 by Dan Kogai E<lt>dankogai@dan.co.jpE<gt>. See AUTHORS for a full
752 list of people involved. For any questions, use
753 E<lt>perl-unicode@perl.orgE<gt> so we can all share.