package Encode;
use strict;
+our $VERSION = do { my @r = (q$Revision: 1.57 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r };
+our $DEBUG = 0;
+use XSLoader ();
+XSLoader::load 'Encode';
-our $VERSION = 0.02;
-
-require DynaLoader;
require Exporter;
-
-our @ISA = qw(Exporter DynaLoader);
+our @ISA = qw(Exporter);
# Public, encouraged API is exported by default
-our @EXPORT = qw (
- encode
- decode
- encode_utf8
- decode_utf8
- find_encoding
- encodings
+
+our @EXPORT = qw(
+ decode decode_utf8 encode encode_utf8
+ 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 @EXPORT_OK =
- qw(
- define_encoding
- define_alias
- from_to
- is_utf8
- is_8bit
- is_16bit
- utf8_upgrade
- utf8_downgrade
- _utf8_on
- _utf8_off
- );
-
-bootstrap Encode ();
+ (
+ qw(
+ _utf8_off _utf8_on define_encoding from_to is_16bit is_8bit
+ is_utf8 perlio_ok resolve_alias utf8_downgrade utf8_upgrade
+ ),
+ @FB_FLAGS, @FB_CONSTS,
+ );
+
+our %EXPORT_TAGS =
+ (
+ all => [ @EXPORT, @EXPORT_OK ],
+ fallbacks => [ @FB_CONSTS ],
+ fallback_all => [ @FB_CONSTS, @FB_FLAGS ],
+ );
# Documentation moved after __END__ for speed - NI-S
use Carp;
-# Make a %encoding package variable to allow a certain amount of cheating
-our %encoding;
-my @alias; # ordered matching list
-my %alias; # cached known aliases
+our $ON_EBCDIC = (ord("A") == 193);
-sub encodings
-{
- my ($class) = @_;
- return keys %encoding;
-}
+use Encode::Alias;
-sub findAlias
+# Make a %Encoding package variable to allow a certain amount of cheating
+our %Encoding;
+our %ExtModule;
+require Encode::Config;
+eval { require Encode::ConfigLocal };
+
+sub encodings
{
- my $class = shift;
- local $_ = shift;
- unless (exists $alias{$_})
- {
- for (my $i=0; $i < @alias; $i += 2)
- {
- my $alias = $alias[$i];
- my $val = $alias[$i+1];
- my $new;
- if (ref($alias) eq 'Regexp' && $_ =~ $alias)
- {
- $new = eval $val;
- }
- elsif (ref($alias) eq 'CODE')
- {
- $new = &{$alias}($val)
- }
- elsif (lc($_) eq $alias)
- {
- $new = $val;
- }
- if (defined($new))
- {
- next if $new eq $_; # avoid (direct) recursion on bugs
- my $enc = (ref($new)) ? $new : find_encoding($new);
- if ($enc)
- {
- $alias{$_} = $enc;
- last;
- }
- }
+ my $class = shift;
+ my @modules = (@_ and $_[0] eq ":all") ? values %ExtModule : @_;
+ for my $mod (@modules){
+ $mod =~ s,::,/,g or $mod = "Encode/$mod";
+ $mod .= '.pm';
+ $DEBUG and warn "about to require $mod;";
+ eval { require $mod; };
}
- }
- return $alias{$_};
+ my %modules = map {$_ => 1} @modules;
+ return
+ sort { lc $a cmp lc $b }
+ grep {!/^(?:Internal|Unicode)$/o} keys %Encoding;
}
-sub define_alias
-{
- while (@_)
- {
- my ($alias,$name) = splice(@_,0,2);
- push(@alias, $alias => $name);
- }
+sub perlio_ok{
+ my $obj = ref($_[0]) ? $_[0] : find_encoding($_[0]);
+ $obj->can("perlio_ok") and return $obj->perlio_ok();
+ return 0; # safety net
}
-define_alias( qr/^iso(\d+-\d+)$/i => '"iso-$1"' );
-define_alias( qr/^(\S+)\s+(.*)$/i => '"$1-$2"' );
-#define_alias( sub { return /^iso-(\d+-\d+)$/i ? "iso$1" : '' } );
-define_alias( 'ascii' => 'US-ascii');
-define_alias( 'ibm-1047' => 'cp1047');
-
sub define_encoding
{
- my $obj = shift;
- my $name = shift;
- $encoding{$name} = $obj;
- my $lc = lc($name);
- define_alias($lc => $obj) unless $lc eq $name;
- while (@_)
- {
- my $alias = shift;
- define_alias($alias,$obj);
- }
- return $obj;
+ my $obj = shift;
+ my $name = shift;
+ $Encoding{$name} = $obj;
+ my $lc = lc($name);
+ define_alias($lc => $obj) unless $lc eq $name;
+ while (@_)
+ {
+ my $alias = shift;
+ define_alias($alias,$obj);
+ }
+ return $obj;
}
sub getEncoding
{
- my ($class,$name) = @_;
- my $enc;
- if (exists $encoding{$name})
- {
- return $encoding{$name};
- }
- else
- {
- return $class->findAlias($name);
- }
-}
+ my ($class,$name,$skip_external) = @_;
+ my $enc;
+ if (ref($name) && $name->can('new_sequence'))
+ {
+ return $name;
+ }
+ my $lc = lc $name;
+ if (exists $Encoding{$name})
+ {
+ return $Encoding{$name};
+ }
+ if (exists $Encoding{$lc})
+ {
+ return $Encoding{$lc};
+ }
-sub find_encoding
-{
- my ($name) = @_;
- return __PACKAGE__->getEncoding($name);
-}
+ my $oc = $class->find_alias($name);
+ return $oc if defined $oc;
-sub encode
-{
- my ($name,$string,$check) = @_;
- my $enc = find_encoding($name);
- croak("Unknown encoding '$name'") unless defined $enc;
- my $octets = $enc->encode($string,$check);
- return undef if ($check && length($string));
- return $octets;
-}
+ $oc = $class->find_alias($lc) if $lc ne $name;
+ return $oc if defined $oc;
-sub decode
-{
- my ($name,$octets,$check) = @_;
- my $enc = find_encoding($name);
- croak("Unknown encoding '$name'") unless defined $enc;
- my $string = $enc->decode($octets,$check);
- return undef if ($check && length($octets));
- return $string;
+ unless ($skip_external)
+ {
+ if (my $mod = $ExtModule{$name} || $ExtModule{$lc}){
+ $mod =~ s,::,/,g ; $mod .= '.pm';
+ eval{ require $mod; };
+ return $Encoding{$name} if exists $Encoding{$name};
+ }
+ }
+ return;
}
-sub from_to
+sub find_encoding
{
- my ($string,$from,$to,$check) = @_;
- my $f = find_encoding($from);
- croak("Unknown encoding '$from'") unless defined $f;
- my $t = find_encoding($to);
- croak("Unknown encoding '$to'") unless defined $t;
- my $uni = $f->decode($string,$check);
- return undef if ($check && length($string));
- $string = $t->encode($uni,$check);
- return undef if ($check && length($uni));
- return length($_[0] = $string);
+ my ($name,$skip_external) = @_;
+ return __PACKAGE__->getEncoding($name,$skip_external);
}
-sub encode_utf8
-{
- my ($str) = @_;
- utf8_encode($str);
- return $str;
+sub resolve_alias {
+ my $obj = find_encoding(shift);
+ defined $obj and return $obj->name;
+ return;
}
-sub decode_utf8
+sub encode($$;$)
{
- my ($str) = @_;
- return undef unless utf8_decode($str);
- return $str;
+ my ($name,$string,$check) = @_;
+ $check ||=0;
+ my $enc = find_encoding($name);
+ croak("Unknown encoding '$name'") unless defined $enc;
+ my $octets = $enc->encode($string,$check);
+ return undef if ($check && length($string));
+ return $octets;
}
-package Encode::Encoding;
-# Base class for classes which implement encodings
-
-sub Define
+sub decode($$;$)
{
- my $obj = shift;
- my $canonical = shift;
- $obj = bless { Name => $canonical },$obj unless ref $obj;
- # warn "$canonical => $obj\n";
- Encode::define_encoding($obj, $canonical, @_);
+ my ($name,$octets,$check) = @_;
+ $check ||=0;
+ my $enc = find_encoding($name);
+ croak("Unknown encoding '$name'") unless defined $enc;
+ my $string = $enc->decode($octets,$check);
+ $_[1] = $octets if $check;
+ return $string;
}
-sub name { shift->{'Name'} }
-
-# Temporary legacy methods
-sub toUnicode { shift->decode(@_) }
-sub fromUnicode { shift->encode(@_) }
-
-sub new_sequence { return $_[0] }
-
-package Encode::XS;
-use base 'Encode::Encoding';
-
-package Encode::Unicode;
-use base 'Encode::Encoding';
-
-# Dummy package that provides the encode interface but leaves data
-# as UTF-8 encoded. It is here so that from_to() works.
-
-__PACKAGE__->Define('Unicode');
-
-sub decode
+sub from_to($$$;$)
{
- my ($obj,$str,$chk) = @_;
- Encode::utf8_upgrade($str);
- $_[1] = '' if $chk;
- return $str;
+ my ($string,$from,$to,$check) = @_;
+ $check ||=0;
+ my $f = find_encoding($from);
+ croak("Unknown encoding '$from'") unless defined $f;
+ my $t = find_encoding($to);
+ croak("Unknown encoding '$to'") unless defined $t;
+ my $uni = $f->decode($string,$check);
+ return undef if ($check && length($string));
+ $string = $t->encode($uni,$check);
+ return undef if ($check && length($uni));
+ return defined($_[0] = $string) ? length($string) : undef ;
}
-*encode = \&decode;
-
-package Encode::utf8;
-use base 'Encode::Encoding';
-# package to allow long-hand
-# $octets = encode( utf8 => $string );
-#
-
-__PACKAGE__->Define(qw(UTF-8 utf8));
-
-sub decode
+sub encode_utf8($)
{
- my ($obj,$octets,$chk) = @_;
- my $str = Encode::decode_utf8($octets);
- if (defined $str)
- {
- $_[1] = '' if $chk;
- return $str;
- }
- return undef;
+ my ($str) = @_;
+ utf8::encode($str);
+ return $str;
}
-sub encode
+sub decode_utf8($)
{
- my ($obj,$string,$chk) = @_;
- my $octets = Encode::encode_utf8($string);
- $_[1] = '' if $chk;
- return $octets;
+ my ($str) = @_;
+ return undef unless utf8::decode($str);
+ return $str;
}
-package Encode::iso10646_1;
-use base 'Encode::Encoding';
-# Encoding is 16-bit network order Unicode (no surogates)
-# Used for X font encodings
+predefine_encodings();
-__PACKAGE__->Define(qw(UCS-2 iso10646-1));
-
-sub decode
-{
- my ($obj,$str,$chk) = @_;
- my $uni = '';
- while (length($str))
- {
- my $code = unpack('n',substr($str,0,2,'')) & 0xffff;
- $uni .= chr($code);
- }
- $_[1] = $str if $chk;
- Encode::utf8_upgrade($uni);
- return $uni;
-}
+#
+# This is to restore %Encoding if really needed;
+#
+sub predefine_encodings{
+ if ($ON_EBCDIC) {
+ # was in Encode::UTF_EBCDIC
+ package Encode::UTF_EBCDIC;
+ *name = sub{ shift->{'Name'} };
+ *new_sequence = sub{ return $_[0] };
+ *decode = sub{
+ my ($obj,$str,$chk) = @_;
+ my $res = '';
+ for (my $i = 0; $i < length($str); $i++) {
+ $res .=
+ chr(utf8::unicode_to_native(ord(substr($str,$i,1))));
+ }
+ $_[1] = '' if $chk;
+ return $res;
+ };
+ *encode = sub{
+ my ($obj,$str,$chk) = @_;
+ my $res = '';
+ for (my $i = 0; $i < length($str); $i++) {
+ $res .=
+ chr(utf8::native_to_unicode(ord(substr($str,$i,1))));
+ }
+ $_[1] = '' if $chk;
+ return $res;
+ };
+ $Encode::Encoding{Unicode} =
+ bless {Name => "UTF_EBCDIC"} => "Encode::UTF_EBCDIC";
+ } else {
+ # was in Encode::UTF_EBCDIC
+ package Encode::Internal;
+ *name = sub{ shift->{'Name'} };
+ *new_sequence = sub{ return $_[0] };
+ *decode = sub{
+ my ($obj,$str,$chk) = @_;
+ utf8::upgrade($str);
+ $_[1] = '' if $chk;
+ return $str;
+ };
+ *encode = \&decode;
+ $Encode::Encoding{Unicode} =
+ bless {Name => "Internal"} => "Encode::Internal";
+ }
-sub encode
-{
- my ($obj,$uni,$chk) = @_;
- my $str = '';
- while (length($uni))
- {
- my $ch = substr($uni,0,1,'');
- my $x = ord($ch);
- unless ($x < 32768)
{
- last if ($chk);
- $x = 0;
+ # was in Encode::utf8
+ package Encode::utf8;
+ *name = sub{ shift->{'Name'} };
+ *new_sequence = sub{ return $_[0] };
+ *decode = sub{
+ my ($obj,$octets,$chk) = @_;
+ my $str = Encode::decode_utf8($octets);
+ if (defined $str) {
+ $_[1] = '' if $chk;
+ return $str;
+ }
+ return undef;
+ };
+ *encode = sub {
+ my ($obj,$string,$chk) = @_;
+ my $octets = Encode::encode_utf8($string);
+ $_[1] = '' if $chk;
+ return $octets;
+ };
+ $Encode::Encoding{utf8} =
+ bless {Name => "utf8"} => "Encode::utf8";
}
- $str .= pack('n',$x);
- }
- $_[1] = $uni if $chk;
- return $str;
}
-# switch back to Encode package in case we ever add AutoLoader
-package Encode;
-
1;
__END__
use Encode;
+=head2 Table of Contents
+
+Encode consists of a collection of modules whose details are too big
+to fit in one document. This POD itself explains the top-level APIs
+and general topics at a glance. For other topics and more details,
+see the PODs below:
+
+ Name Description
+ --------------------------------------------------------
+ Encode::Alias Alias definitions to encodings
+ Encode::Encoding Encode Implementation Base Class
+ Encode::Supported List of Supported Encodings
+ Encode::CN Simplified Chinese Encodings
+ Encode::JP Japanese Encodings
+ Encode::KR Korean Encodings
+ Encode::TW Traditional Chinese Encodings
+ --------------------------------------------------------
+
=head1 DESCRIPTION
-The C<Encode> module provides the interfaces between perl's strings
-and the rest of the system. Perl strings are sequences of B<characters>.
+The C<Encode> module provides the interfaces between Perl's strings
+and the rest of the system. Perl strings are sequences of
+B<characters>.
The repertoire of characters that Perl can represent is at least that
-defined by the Unicode Consortium. On most platforms the ordinal values
-of the characters (as returned by C<ord(ch)>) is the "Unicode codepoint" for
-the character (the exceptions are those platforms where the legacy
-encoding is some variant of EBCDIC rather than a super-set of ASCII
-- see L<perlebcdic>).
+defined by the Unicode Consortium. On most platforms the ordinal
+values of the characters (as returned by C<ord(ch)>) is the "Unicode
+codepoint" for the character (the exceptions are those platforms where
+the legacy encoding is some variant of EBCDIC rather than a super-set
+of ASCII - see L<perlebcdic>).
-Traditionaly computer data has been moved around in 8-bit chunks
+Traditionally, computer data has been moved around in 8-bit chunks
often called "bytes". These chunks are also known as "octets" in
-networking standards. Perl is widely used to manipulate data of
-many types - not only strings of characters representing human or
-computer languages but also "binary" data being the machines representation
-of numbers, pixels in an image - or just about anything.
+networking standards. Perl is widely used to manipulate data of many
+types - not only strings of characters representing human or computer
+languages but also "binary" data being the machine's representation of
+numbers, pixels in an image - or just about anything.
-When perl is processing "binary data" the programmer wants perl to process
-"sequences of bytes". This is not a problem for perl - as a byte has 256
-possible values it easily fits in perl's much larger "logical character".
+When Perl is processing "binary data", the programmer wants Perl to
+process "sequences of bytes". This is not a problem for Perl - as a
+byte has 256 possible values, it easily fits in Perl's much larger
+"logical character".
=head2 TERMINOLOGY
=item *
I<character>: a character in the range 0..(2**32-1) (or more).
-(What perl's strings are made of.)
+(What Perl's strings are made of.)
=item *
I<byte>: a character in the range 0..255
-(A special case of a perl character.)
+(A special case of a Perl character.)
=item *
I<octet>: 8 bits of data, with ordinal values 0..255
-(Term for bytes passed to or from a non-perl context, e.g. disk file.)
+(Term for bytes passed to or from a non-Perl context, e.g. a disk file.)
=back
general meant only for those who think they know what they are doing,
and such details may change in future releases.
-=head1 ENCODINGS
-
-=head2 Characteristics of an Encoding
-
-An encoding has a "repertoire" of characters that it can represent,
-and for each representable character there is at least one sequence of
-octets that represents it.
-
-=head2 Types of Encodings
-
-Encodings can be divided into the following types:
-
-=over 4
-
-=item * Fixed length 8-bit (or less) encodings.
-
-Each character is a single octet so may have a repertoire of up to
-256 characters. ASCII and iso-8859-* are typical examples.
-
-=item * Fixed length 16-bit encodings
-
-Each character is two octets so may have a repertoire of up to
-65,536 characters. Unicode's UCS-2 is an example. Also used for
-encodings for East Asian languages.
-
-=item * Fixed length 32-bit encodings.
-
-Not really very "encoded" encodings. The Unicode code points
-are just represented as 4-octet integers. None the less because
-different architectures use different representations of integers
-(so called "endian") there at least two disctinct encodings.
-
-=item * Multi-byte encodings
-
-The number of octets needed to represent a character varies.
-UTF-8 is a particularly complex but regular case of a multi-byte
-encoding. Several East Asian countries use a multi-byte encoding
-where 1-octet is used to cover western roman characters and Asian
-characters get 2-octets.
-(UTF-16 is strictly a multi-byte encoding taking either 2 or 4 octets
-to represent a Unicode code point.)
-
-=item * "Escape" encodings.
-
-These encodings embed "escape sequences" into the octet sequence
-which describe how the following octets are to be interpreted.
-The iso-2022-* family is typical. Following the escape sequence
-octets are encoded by an "embedded" encoding (which will be one
-of the above types) until another escape sequence switches to
-a different "embedded" encoding.
-
-These schemes are very flexible and can handle mixed languages but are
-very complex to process (and have state).
-No escape encodings are implemented for perl yet.
-
-=back
-
-=head2 Specifying Encodings
-
-Encodings can be specified to the API described below in two ways:
-
-=over 4
-
-=item 1. By name
-
-Encoding names are strings with characters taken from a restricted repertoire.
-See L</"Encoding Names">.
-
-=item 2. As an object
-
-Encoding objects are returned by C<find_encoding($name)>.
-
-=back
-
-=head2 Encoding Names
-
-Encoding names are case insensitive. White space in names is ignored.
-In addition an encoding may have aliases. Each encoding has one "canonical" name.
-The "canonical" name is chosen from the names of the encoding by picking
-the first in the following sequence:
-
-=over 4
-
-=item * The MIME name as defined in IETF RFC-XXXX.
-
-=item * The name in the IANA registry.
-
-=item * The name used by the the organization that defined it.
-
-=back
-
-Because of all the alias issues, and because in the general case
-encodings have state C<Encode> uses the encoding object internally
-once an operation is in progress.
-
=head1 PERL ENCODING API
-=head2 Generic Encoding Interface
-
=over 4
-=item *
-
- $bytes = encode(ENCODING, $string[, CHECK])
-
-Encodes string from perl's internal form into I<ENCODING> and returns a
-sequence of octets.
-See L</"Handling Malformed Data">.
-
-=item *
-
- $string = decode(ENCODING, $bytes[, CHECK])
-
-Decode sequence of octets assumed to be in I<ENCODING> into perls internal
-form and returns the resuting string.
-See L</"Handling Malformed Data">.
-
-=back
-
-=head2 Handling Malformed Data
-
-If CHECK is not set, C<undef> is returned. If the data is supposed to
-be UTF-8, an optional lexical warning (category utf8) is given.
-If CHECK is true but not a code reference, dies.
-
-It would desirable to have a way to indicate that transform should use the
-encodings "replacement character" - no such mechanism is defined yet.
+=item $octets = encode(ENCODING, $string[, CHECK])
-It is also planned to allow I<CHECK> to be a code reference.
+Encodes a string from Perl's internal form into I<ENCODING> and returns
+a sequence of octets. ENCODING can be either a canonical name or
+an alias. For encoding names and aliases, see L</"Defining Aliases">.
+For CHECK, see L</"Handling Malformed Data">.
-This is not yet implemented as there are design issues with what its arguments
-should be and how it returns its results.
+For example, to convert (internally UTF-8 encoded) Unicode string to
+iso-8859-1 (also known as Latin1),
-=over 4
-
-=item Scheme 1
+ $octets = encode("iso-8859-1", $unicode);
-Passed remaining fragment of string being processed.
-Modifies it in place to remove bytes/characters it can understand
-and returns a string used to represent them.
-e.g.
+=item $string = decode(ENCODING, $octets[, CHECK])
- sub fixup {
- my $ch = substr($_[0],0,1,'');
- return sprintf("\x{%02X}",ord($ch);
- }
+Decodes a sequence of octets assumed to be in I<ENCODING> into Perl's
+internal form and returns the resulting string. As in encode(),
+ENCODING can be either a canonical name or an alias. For encoding names
+and aliases, see L</"Defining Aliases">. For CHECK, see
+L</"Handling Malformed Data">.
-This scheme is close to how underlying C code for Encode works, but gives
-the fixup routine very little context.
+For example, to convert ISO-8859-1 data to UTF-8:
-=item Scheme 2
+ $utf8 = decode("iso-8859-1", $latin1);
-Passed original string, and an index into it of the problem area,
-and output string so far.
-Appends what it will to output string and returns new index into
-original string.
-e.g.
+=item [$length =] from_to($string, FROM_ENCODING, TO_ENCODING [,CHECK])
- sub fixup {
- # my ($s,$i,$d) = @_;
- my $ch = substr($_[0],$_[1],1);
- $_[2] .= sprintf("\x{%02X}",ord($ch);
- return $_[1]+1;
- }
+Converts B<in-place> data between two encodings.
+For example, to convert ISO-8859-1 data to UTF-8:
-This scheme gives maximal control to the fixup routine but is more complicated
-to code, and may need internals of Encode to be tweaked to keep original
-string intact.
+ from_to($data, "iso-8859-1", "utf-8");
-=item Other Schemes
+and to convert it back:
-Hybrids of above.
+ from_to($data, "utf-8", "iso-8859-1");
-Multiple return values rather than in-place modifications.
+Note that because the conversion happens in place, the data to be
+converted cannot be a string constant; it must be a scalar variable.
-Index into the string could be pos($str) allowing s/\G...//.
+from_to() returns the length of the converted string on success, undef
+otherwise.
=back
=head2 UTF-8 / utf8
-The Unicode consortium defines the UTF-8 standard as a way of encoding
-the entire Unicode repertiore as sequences of octets. This encoding
-is expected to become very widespread. Perl can use this form internaly
-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).
+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).
=over 4
-=item *
+=item $octets = encode_utf8($string);
- $bytes = encode_utf8($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.
-The characters that comprise string are encoded in perl's superset of UTF-8
-and the resulting octets 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]);
-=item *
-
- $string = decode_utf8($bytes [,CHECK]);
-
-The sequence of octets represented by $bytes 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.
-See L</"Handling Malformed Data">.
+The sequence of octets represented by $octets is decoded from UTF-8
+into a sequence of logical characters. Not all sequences of octets
+form valid UTF-8 encodings, so it is possible for this call to fail.
+For CHECK, see L</"Handling Malformed Data">.
=back
-=head2 Other Encodings of Unicode
+=head2 Listing available encodings
-UTF-16 is similar to UCS-2, 16 bit or 2-byte chunks.
-UCS-2 can only represent 0..0xFFFF, while UTF-16 has a "surogate pair"
-scheme which allows it to cover the whole Unicode range.
+ use Encode;
+ @list = Encode->encodings();
-Encode implements big-endian UCS-2 aliased to "iso10646-1" as that
-happens to be the name used by that representation when used with X11 fonts.
+Returns a list of the canonical names of the available encodings that
+are loaded. To get a list of all available encodings including the
+ones that are not loaded yet, say
-UTF-32 or UCS-4 is 32-bit or 4-byte chunks. Perl's logical characters
-can be considered as being in this form without encoding. An encoding
-to transfer strings in this form (e.g. to write them to a file) would need to
+ @all_encodings = Encode->encodings(":all");
- pack('L',map(chr($_),split(//,$string))); # native
- or
- pack('V',map(chr($_),split(//,$string))); # little-endian
- or
- pack('N',map(chr($_),split(//,$string))); # big-endian
+Or you can give the name of a specific module.
-depending on the endian required.
+ @with_jp = Encode->encodings("Encode::JP");
-No UTF-32 encodings are implemented yet.
+When "::" is not in the name, "Encode::" is assumed.
-Both UCS-2 and UCS-4 style encodings can have "byte order marks" by representing
-the code point 0xFFFE as the very first thing in a file.
+ @ebcdic = Encode->encodings("EBCDIC");
-=head2 Listing available encodings
+To find out in detail which encodings are supported by this package,
+see L<Encode::Supported>.
- use Encode qw(encodings);
- @list = encodings();
+=head2 Defining Aliases
-Returns a list of the canonical names of the available encodings.
+To add a new alias to a given encoding, use:
-=head2 Defining Aliases
+ use Encode;
+ use Encode::Alias;
+ define_alias(newName => ENCODING);
- use Encode qw(define_alias);
- define_alias( newName => ENCODING);
+After that, newName can be used as an alias for ENCODING.
+ENCODING may be either the name of an encoding or an
+I<encoding object>
-Allows newName to be used as am alias for ENCODING. ENCODING may be either the
-name of an encoding or and encoding object (as above).
+But before you do so, make sure the alias is nonexistent with
+C<resolve_alias()>, which returns the canonical name thereof.
+i.e.
-Currently I<newName> can be specified in the following ways:
+ Encode::resolve_alias("latin1") eq "iso-8859-1" # true
+ Encode::resolve_alias("iso-8859-12") # false; nonexistent
+ Encode::resolve_alias($name) eq $name # true if $name is canonical
-=over 4
+resolve_alias() does not need C<use Encode::Alias>; it can be
+exported via C<use Encode qw(resolve_alias)>.
-=item As a simple string.
+See L<Encode::Alias> for details.
-=item As a qr// compiled regular expression, e.g.:
+=head1 Encoding via PerlIO
- define_alias( qr/^iso8859-(\d+)$/i => '"iso-8859-$1"' );
+If your perl supports I<PerlIO>, you can use a PerlIO layer to decode
+and encode directly via a filehandle. The following two examples
+are totally identical in their functionality.
-In this case if I<ENCODING> is not a reference it is C<eval>-ed to allow
-C<$1> etc. to be subsituted.
-The example is one way to names as used in X11 font names to alias the MIME names for the
-iso-8859-* family.
+ # via PerlIO
+ open my $in, "<:encoding(shiftjis)", $infile or die;
+ open my $out, ">:encoding(euc-jp)", $outfile or die;
+ while(<>){ print; }
-=item As a code reference, e.g.:
+ # via from_to
+ open my $in, "<", $infile or die;
+ open my $out, ">", $outfile or die;
+ while(<>){
+ from_to($_, "shiftjis", "euc-jp", 1);
+ }
- define_alias( sub { return /^iso8859-(\d+)$/i ? "iso-8859-$1" : undef } , '');
+Unfortunately, there may be encodings are PerlIO-savvy. You can check
+if your encoding is supported by PerlIO by calling the C<perlio_ok>
+method.
-In this case C<$_> will be set to the name that is being looked up and
-I<ENCODING> is passed to the sub as its first argument.
-The example is another way to names as used in X11 font names to alias the MIME names for
-the iso-8859-* family.
+ Encode::perlio_ok("hz"); # False
+ find_encoding("euc-cn")->perlio_ok; # True where PerlIO is available
-=back
+ use Encode qw(perlio_ok); # exported upon request
+ perlio_ok("euc-jp")
-=head2 Defining Encodings
+Fortunately, all encodings that come with Encode core are PerlIO-savvy
+except for hz and ISO-2022-kr. See L<Encode::Encoding> for details.
- use Encode qw(define_alias);
- define_encoding( $object, 'canonicalName' [,alias...]);
+For gory details, see L<Encode::PerlIO>.
-Causes I<canonicalName> to be associated with I<$object>.
-The object should provide the interface described in L</"IMPLEMENTATION CLASSES"> below.
-If more than two arguments are provided then additional arguments are taken
-as aliases for I<$object> as for C<define_alias>.
+=head1 Handling Malformed Data
-=head1 Encoding and IO
+=over 4
-It is very common to want to do encoding transformations when
-reading or writing files, network connections, pipes etc.
-If perl is configured to use the new 'perlio' IO system then
-C<Encode> provides a "layer" (See L<perliol>) which can transform
-data as it is read or written.
+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
+I<CHECK>.
+
+=item I<CHECK> = Encode::FB_DEFAULT ( == 0)
+
+If I<CHECK> is 0, (en|de)code will put a I<substitution character>
+in place of a malformed character. For UCM-based encodings,
+E<lt>subcharE<gt> will be used. For Unicode, "\x{FFFD}" is used.
+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)
+
+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
+fatal error with eval{} unless you really want to let it die on error.
+
+=item I<CHECK> = Encode::FB_QUIET
+
+If I<CHECK> is set to Encode::FB_QUIET, (en|de)code will immediately
+return the portion of the data that has been processed so far when
+an error occurs. The data argument will be overwritten with
+everything after that point (that is, the unprocessed part of data).
+This is handy when you have to call decode repeatedly in the case
+where your source data may contain partial multi-byte character
+sequences, for example because you are reading with a fixed-width
+buffer. Here is some sample code that does exactly this:
+
+ my $data = '';
+ while(defined(read $fh, $buffer, 256)){
+ # buffer may end in a partial character so we append
+ $data .= $buffer;
+ $utf8 .= decode($encoding, $data, ENCODE::FB_QUIET);
+ # $data now contains the unprocessed partial character
+ }
- open(my $ilyad,'>:encoding(iso-8859-7)','ilyad.greek');
- print $ilyad @epic;
+=item I<CHECK> = Encode::FB_WARN
-In addition the new IO system can also be configured to read/write
-UTF-8 encoded characters (as noted above this is efficient):
+This is the same as above, except that it warns on error. Handy when
+you are debugging the mode above.
- open(my $fh,'>:utf8','anything');
- print $fh "Any \x{0021} string \N{SMILEY FACE}\n";
+=item perlqq mode (I<CHECK> = Encode::FB_PERLQQ)
-Either of the above forms of "layer" specifications can be made the default
-for a lexical scope with the C<use open ...> pragma. See L<open>.
+For encodings that are implemented by Encode::XS, CHECK ==
+Encode::FB_PERLQQ turns (en|de)code into C<perlqq> fallback mode.
-Once a handle is open is layers can be altered using C<binmode>.
+When you decode, '\xI<XX>' will be inserted for a malformed character,
+where I<XX> is the hex representation of the octet that could not be
+decoded to utf8. And when you encode, '\x{I<xxxx>}' will be inserted,
+where I<xxxx> is the Unicode ID of the character that cannot be found
+in the character repertoire of the encoding.
-Without any such configuration, or if perl itself is built using
-system's own IO, then write operations assume that file handle accepts
-only I<bytes> and will C<die> if a character larger than 255 is
-written to the handle. When reading, each octet from the handle
-becomes a byte-in-a-character. Note that this default is the same
-behaviour as bytes-only languages (including perl before v5.6) would have,
-and is sufficient to handle native 8-bit encodings e.g. iso-8859-1,
-EBCDIC etc. and any legacy mechanisms for handling other encodings
-and binary data.
+=item The bitmask
-In other cases it is the programs responsibility
-to transform characters into bytes using the API above before
-doing writes, and to transform the bytes read from a handle into characters
-before doing "character operations" (e.g. C<lc>, C</\W+/>, ...).
+These modes are actually set via a bitmask. Here is how the FB_XX
+constants are laid out. You can import the FB_XX constants via
+C<use Encode qw(:fallbacks)>; you can import the generic bitmask
+constants via C<use Encode qw(:fallback_all)>.
-=head1 Encoding How to ...
+ FB_DEFAULT FB_CROAK FB_QUIET FB_WARN FB_PERLQQ
+ DIE_ON_ERR 0x0001 X
+ WARN_ON_ER 0x0002 X
+ RETURN_ON_ERR 0x0004 X X
+ LEAVE_SRC 0x0008
+ PERLQQ 0x0100 X
-To do:
+=head2 Unimplemented fallback schemes
-=over 4
+In the future, you will be able to use a code reference to a callback
+function for the value of I<CHECK> but its API is still undecided.
-=item * IO with mixed content (faking iso-2020-*)
+=head1 Defining Encodings
-=item * MIME's Content-Length:
+To define a new encoding, use:
-=item * UTF-8 strings in binary data.
+ use Encode qw(define_alias);
+ define_encoding($object, 'canonicalName' [, alias...]);
-=item * perl/Encode wrappers on non-Unicode XS modules.
+I<canonicalName> will be associated with I<$object>. The object
+should provide the interface described in L<Encode::Encoding>.
+If more than two arguments are provided then additional
+arguments are taken as aliases for I<$object>, as for C<define_alias>.
-=back
+See L<Encode::Encoding> for more details.
=head1 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.
+The following API uses parts of Perl's internals in the current
+implementation. As such, they are efficient but may change.
=over 4
-=item *
-
- $num_octets = utf8_upgrade($string);
-
-Converts internal representation of string to the UTF-8 form.
-Returns the number of octets necessary to represent the string as UTF-8.
-
-=item * utf8_downgrade($string[, CHECK])
-
-Converts internal representation of string to be un-encoded bytes.
-
-=item * is_utf8(STRING [, CHECK])
-
-[INTERNAL] Test whether the UTF-8 flag is turned on in the STRING.
-If CHECK is true, also checks the data in STRING for being
-well-formed UTF-8. Returns true if successful, false otherwise.
-
-=item * valid_utf8(STRING)
-
-[INTERNAL] Test whether STRING is in a consistent state.
-Will return true if string is held as bytes, or is well-formed UTF-8
-and has the UTF-8 flag on.
-Main reason for this routine is to allow perl's testsuite to check
-that operations have left strings in a consistent state.
+=item is_utf8(STRING [, CHECK])
-=item *
+[INTERNAL] Tests whether the UTF-8 flag is turned on in the STRING.
+If CHECK is true, also checks the data in STRING for being well-formed
+UTF-8. Returns true if successful, false otherwise.
- _utf8_on(STRING)
+=item _utf8_on(STRING)
-[INTERNAL] Turn on the UTF-8 flag in STRING. The data in STRING is
+[INTERNAL] Turns on the UTF-8 flag in STRING. The data in STRING is
B<not> checked for being well-formed UTF-8. Do not use unless you
B<know> that the STRING is well-formed UTF-8. Returns the previous
-state of the UTF-8 flag (so please don't test the return value as
-I<not> success or failure), or C<undef> if STRING is not a string.
-
-=item *
+state of the UTF-8 flag (so please don't treat the return value as
+indicating success or failure), or C<undef> if STRING is not a string.
- _utf8_off(STRING)
+=item _utf8_off(STRING)
-[INTERNAL] Turn off the UTF-8 flag in STRING. Do not use frivolously.
-Returns the previous state of the UTF-8 flag (so please don't test the
-return value as I<not> success or failure), or C<undef> if STRING is
+[INTERNAL] Turns off the UTF-8 flag in STRING. Do not use frivolously.
+Returns the previous state of the UTF-8 flag (so please don't treat the
+return value as indicating success or failure), or C<undef> if STRING is
not a string.
=back
-=head1 IMPLEMENTATION CLASSES
-
-As mentioned above encodings are (in the current implementation at least)
-defined by objects. The mapping of encoding name to object is via the
-C<%encodings> hash.
-
-The values of the hash can currently be either strings or objects.
-The string form may go away in the future. The string form occurs
-when C<encodings()> has scanned C<@INC> for loadable encodings but has
-not actually loaded the encoding in question. This is because the
-current "loading" process is all perl and a bit slow.
-
-Once an encoding is loaded then value of the hash is object which implements
-the encoding. The object should provide the following interface:
-
-=over 4
-
-=item -E<gt>name
-
-Should return the string representing the canonical name of the encoding.
-
-=item -E<gt>new_sequence
-
-This is a placeholder for encodings with state. It should return an object
-which implements this interface, all current implementations return the
-original object.
-
-=item -E<gt>encode($string,$check)
-
-Should return the octet sequence representing I<$string>. If I<$check> is true
-it should modify I<$string> in place to remove the converted part (i.e.
-the whole string unless there is an error).
-If an error occurs it should return the octet sequence for the
-fragment of string that has been converted, and modify $string in-place
-to remove the converted part leaving it starting with the problem fragment.
-
-If check is is false then C<encode> should make a "best effort" to convert
-the string - for example by using a replacement character.
-
-=item -E<gt>decode($octets,$check)
-
-Should return the string that I<$octets> represents. If I<$check> is true
-it should modify I<$octets> in place to remove the converted part (i.e.
-the whole sequence unless there is an error).
-If an error occurs it should return the fragment of string
-that has been converted, and modify $octets in-place to remove the converted part
-leaving it starting with the problem fragment.
-
-If check is is false then C<decode> should make a "best effort" to convert
-the string - for example by using Unicode's "\x{FFFD}" as a replacement character.
-
-=back
-
-It should be noted that the check behaviour is different from the outer
-public API. The logic is that the "unchecked" case is useful when
-encoding is part of a stream which may be reporting errors (e.g. STDERR).
-In such cases it is desirable to get everything through somehow without
-causing additional errors which obscure the original one. Also the encoding
-is best placed to know what the correct replacement character is, so if that
-is the desired behaviour then letting low level code do it is the most efficient.
-
-In contrast if check is true, the scheme above allows the encoding to do as
-much as it can and tell layer above how much that was. What is lacking
-at present is a mechanism to report what went wrong. The most likely interface
-will be an additional method call to the object, or perhaps
-(to avoid forcing per-stream objects on otherwise stateless encodings)
-and additional parameter.
-
-It is also highly desirable that encoding classes inherit from C<Encode::Encoding>
-as a base class. This allows that class to define additional behaviour for
-all encoding objects. For example built in Unicode, UCS-2 and UTF-8 classes
-use :
-
- package Encode::MyEncoding;
- use base qw(Encode::Encoding);
-
- __PACKAGE__->Define(qw(myCanonical myAlias));
-
-To create an object with bless {Name => ...},$class, and call define_encoding.
-They inherit their C<name> method from C<Encode::Encoding>.
-
-=head2 Compiled Encodings
-
-F<Encode.xs> provides a class C<Encode::XS> which provides the interface described
-above. It calls a generic octet-sequence to octet-sequence "engine" that is
-driven by tables (defined in F<encengine.c>). The same engine is used for both
-encode and decode. C<Encode:XS>'s C<encode> forces perl's characters to their UTF-8 form
-and then treats them as just another multibyte encoding. C<Encode:XS>'s C<decode> transforms
-the sequence and then turns the UTF-8-ness flag as that is the form that the tables
-are defined to produce. For details of the engine see the comments in F<encengine.c>.
-
-The tables are produced by the perl script F<compile> (the name needs to change so
-we can eventually install it somewhere). F<compile> can currently read two formats:
-
-=over 4
-
-=item *.enc
-
-This is a coined format used by Tcl. It is documented in Encode/EncodeFormat.pod.
-
-=item *.ucm
-
-This is the semi-standard format used by IBM's ICU package.
-
-=back
-
-F<compile> can write the following forms:
-
-=over 4
-
-=item *.ucm
-
-See above - the F<Encode/*.ucm> files provided with the distribution have
-been created from the original Tcl .enc files using this approach.
-
-=item *.c
-
-Produces tables as C data structures - this is used to build in encodings
-into F<Encode.so>/F<Encode.dll>.
-
-=item *.xs
-
-In theory this allows encodings to be stand-alone loadable perl extensions.
-The process has not yet been tested. The plan is to use this approach
-for large East Asian encodings.
-
-=back
-
-The set of encodings built-in to F<Encode.so>/F<Encode.dll> is determined by
-F<Makefile.PL>. The current set is as follows:
-
-=over 4
-
-=item ascii and iso-8859-*
-
-That is all the common 8-bit "western" encodings.
-
-=item IBM-1047 and two other variants of EBCDIC.
-
-These are the same variants that are supported by EBCDIC perl as "native" encodings.
-They are included to prove "reversibility" of some constructs in EBCDIC perl.
-
-=item symbol and dingbats as used by Tk on X11.
-
-(The reason Encode got started was to support perl/Tk.)
-
-=back
-
-That set is rather ad. hoc. and has been driven by the needs of the tests rather
-than the needs of typical applications. It is likely to be rationalized.
-
=head1 SEE ALSO
-L<perlunicode>, L<perlebcdic>, L<perlfunc/open>
-
-=cut
+L<Encode::Encoding>,
+L<Encode::Supported>,
+L<Encode::PerlIO>,
+L<encoding>,
+L<perlebcdic>,
+L<perlfunc/open>,
+L<perlunicode>,
+L<utf8>,
+the Perl Unicode Mailing List E<lt>perl-unicode@perl.orgE<gt>
+=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.
+=cut