package Encode;
use strict;
-
-our $VERSION = 0.02;
+our $VERSION = do { my @r = (q$Revision: 1.20 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r };
+our $DEBUG = 0;
require DynaLoader;
require Exporter;
our @EXPORT_OK =
qw(
define_encoding
- define_alias
from_to
is_utf8
is_8bit
use Carp;
-# Make a %encoding package variable to allow a certain amount of cheating
-our %encoding;
-my @alias; # ordered matching list
-my %alias; # cached known aliases
-
-sub encodings
-{
- my ($class) = @_;
- return keys %encoding;
-}
-
-sub findAlias
-{
- 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 lc($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;
- }
- }
- }
- }
- return $alias{$_};
+our $ON_EBCDIC = (ord("A") == 193);
+use Encode::Alias;
+
+# Make a %Encoding package variable to allow a certain amount of cheating
+our %Encoding;
+our %ExtModule;
+
+my @codepages = qw(
+ 37 424 437 500 737 775 850 852 855
+ 856 857 860 861 862 863 864 865 866
+ 869 874 875 932 936 949 950 1006 1026
+ 1047 1250 1251 1252 1253 1254 1255 1256 1257
+ 1258
+ );
+
+my @macintosh = qw(
+ CentralEurRoman Croatian Cyrillic Greek
+ Iceland Roman Rumanian Sami
+ Thai Turkish Ukrainian
+ );
+
+for my $k (2..11,13..16){
+ $ExtModule{"iso-8859-$k"} = 'Encode/Byte.pm';
}
-sub define_alias
-{
- while (@_)
- {
- my ($alias,$name) = splice(@_,0,2);
- push(@alias, $alias => $name);
- }
+for my $k (@codepages){
+ $ExtModule{"cp$k"} = 'Encode/Byte.pm';
}
-# Allow variants of iso-8859-1 etc.
-define_alias( qr/^iso[-_]?(\d+)[-_](\d+)$/i => '"iso-$1-$2"' );
-
-# Allow latin-1 style names as well
- # 0 1 2 3 4 5 6 7 8 9 10
-my @latin2iso_num = ( 0, 1, 2, 3, 4, 9, 10, 13, 14, 15, 16 );
-define_alias( qr/^latin[-_]?(\d+)$/i => '"iso-8859-$latin2iso_num[$1]"' );
-
-# Common names for non-latin prefered MIME names
-define_alias( 'ascii' => 'US-ascii',
- 'cyrillic' => 'iso-8859-5',
- 'arabic' => 'iso-8859-6',
- 'greek' => 'iso-8859-7',
- 'hebrew' => 'iso-8859-8');
-
-define_alias( 'ibm-1047' => 'cp1047');
-
-# Map white space and _ to '-'
-define_alias( qr/^(\S+)[\s_]+(.*)$/i => '"$1-$2"' );
-
-sub define_encoding
+for my $k (@macintosh)
{
- 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;
+ $ExtModule{"mac$k"} = 'Encode/Byte.pm';
}
-sub getEncoding
-{
- my ($class,$name) = @_;
- my $enc;
- if (exists $encoding{$name})
- {
- return $encoding{$name};
- }
- else
- {
- return $class->findAlias($name);
- }
-}
+%ExtModule =
+ (%ExtModule,
+ 'koi8-r' => 'Encode/Byte.pm',
+ 'posix-bc' => 'Encode/EBCDIC.pm',
+ cp037 => 'Encode/EBCDIC.pm',
+ cp1026 => 'Encode/EBCDIC.pm',
+ cp1047 => 'Encode/EBCDIC.pm',
+ cp500 => 'Encode/EBCDIC.pm',
+ cp875 => 'Encode/EBCDIC.pm',
+ dingbats => 'Encode/Symbol.pm',
+ macDingbats => 'Encode/Symbol.pm',
+ macSymbol => 'Encode/Symbol.pm',
+ symbol => 'Encode/Symbol.pm',
+ viscii => 'Encode/Byte.pm',
+);
-sub find_encoding
-{
- my ($name) = @_;
- return __PACKAGE__->getEncoding($name);
+unless ($ON_EBCDIC) { # CJK added to autoload unless EBCDIC env
+%ExtModule =(%ExtModule,
+ 'euc-cn' => 'Encode/CN.pm',
+ gb2312 => 'Encode/CN.pm',
+ gb12345 => 'Encode/CN.pm',
+ gbk => 'Encode/CN.pm',
+ cp936 => 'Encode/CN.pm',
+ 'iso-ir-165' => 'Encode/CN.pm',
+ 'euc-jp' => 'Encode/JP.pm',
+ 'iso-2022-jp' => 'Encode/JP.pm',
+ 'iso-2022-jp-1' => 'Encode/JP.pm',
+ '7bit-jis' => 'Encode/JP.pm',
+ shiftjis => 'Encode/JP.pm',
+ macJapanese => 'Encode/JP.pm',
+ cp932 => 'Encode/JP.pm',
+ 'euc-kr' => 'Encode/KR.pm',
+ ksc5601 => 'Encode/KR.pm',
+ macKorean => 'Encode/KR.pm',
+ cp949 => 'Encode/KR.pm',
+ big5 => 'Encode/TW.pm',
+ 'big5-hkscs' => 'Encode/TW.pm',
+ cp950 => 'Encode/TW.pm',
+ gb18030 => 'Encode/HanExtra.pm',
+ big5plus => 'Encode/HanExtra.pm',
+ 'euc-tw' => 'Encode/HanExtra.pm',
+ );
}
-sub encode
-{
- my ($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 $octets;
-}
-sub decode
-{
- my ($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 $string;
-}
-sub from_to
-{
- my ($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] = $string);
-}
-sub encode_utf8
+sub encodings
{
- my ($str) = @_;
- utf8::encode($str);
- return $str;
+ my $class = shift;
+ my @modules = (@_ and $_[0] eq ":all") ? values %ExtModule : @_;
+ for my $m (@modules)
+ {
+ $DEBUG and warn "about to require $m;";
+ eval { require $m; };
+ }
+ return
+ map({$_->[0]}
+ sort({$a->[1] cmp $b->[1]}
+ map({[$_, lc $_]}
+ grep({ $_ ne 'Internal' } keys %Encoding))));
}
-sub decode_utf8
+sub define_encoding
{
- my ($str) = @_;
- return undef unless utf8::decode($str);
- return $str;
+ 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;
}
-package Encode::Encoding;
-# Base class for classes which implement encodings
-
-sub Define
+sub getEncoding
{
- my $obj = shift;
- my $canonical = shift;
- $obj = bless { Name => $canonical },$obj unless ref $obj;
- # warn "$canonical => $obj\n";
- Encode::define_encoding($obj, $canonical, @_);
-}
-
-sub name { shift->{'Name'} }
-
-# Temporary legacy methods
-sub toUnicode { shift->decode(@_) }
-sub fromUnicode { shift->encode(@_) }
-
-sub new_sequence { return $_[0] }
-
-package Encode::XS;
-use base 'Encode::Encoding';
-
-package Encode::Internal;
-use base 'Encode::Encoding';
+ my ($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};
+ }
-# Dummy package that provides the encode interface but leaves data
-# as UTF-X encoded. It is here so that from_to() works.
+ my $oc = $class->find_alias($name);
+ return $oc if defined $oc;
-__PACKAGE__->Define('Internal');
+ $oc = $class->find_alias($lc) if $lc ne $name;
+ return $oc if defined $oc;
-Encode::define_alias( 'Unicode' => 'Internal' ) if ord('A') == 65;
+ if (!$skip_external and exists $ExtModule{$lc})
+ {
+ eval{ require $ExtModule{$lc}; };
+ return $Encoding{$name} if exists $Encoding{$name};
+ }
-sub decode
-{
- my ($obj,$str,$chk) = @_;
- utf8::upgrade($str);
- $_[1] = '' if $chk;
- return $str;
+ return;
}
-*encode = \&decode;
-
-package Encoding::Unicode;
-use base 'Encode::Encoding';
-
-__PACKAGE__->Define('Unicode') unless ord('A') == 65;
-
-sub decode
+sub find_encoding
{
- my ($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 $res;
+ my ($name,$skip_external) = @_;
+ return __PACKAGE__->getEncoding($name,$skip_external);
}
sub encode
{
- my ($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 $res;
+ my ($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;
}
-
-package Encode::utf8;
-use base 'Encode::Encoding';
-# package to allow long-hand
-# $octets = encode( utf8 => $string );
-#
-
-__PACKAGE__->Define(qw(UTF-8 utf8));
-
sub decode
{
- my ($obj,$octets,$chk) = @_;
- my $str = Encode::decode_utf8($octets);
- if (defined $str)
- {
- $_[1] = '' if $chk;
- return $str;
- }
- return undef;
+ my ($name,$octets,$check) = @_;
+ my $enc = find_encoding($name);
+ croak("Unknown encoding '$name'") unless defined $enc;
+ my $string = $enc->decode($octets,$check);
+ $_[1] = $octets if $check;
+ return $string;
}
-sub encode
+sub from_to
{
- my ($obj,$string,$chk) = @_;
- my $octets = Encode::encode_utf8($string);
- $_[1] = '' if $chk;
- return $octets;
+ my ($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($uni));
+ return defined($_[0] = $string) ? length($string) : undef ;
}
-package Encode::iso10646_1;
-use base 'Encode::Encoding';
-# Encoding is 16-bit network order Unicode (no surogates)
-# Used for X font encodings
-
-__PACKAGE__->Define(qw(UCS-2 iso-10646-1));
-
-sub decode
+sub encode_utf8
{
- my ($obj,$str,$chk) = @_;
- my $uni = '';
- while (length($str))
- {
- my $code = unpack('n',substr($str,0,2,'')) & 0xffff;
- $uni .= chr($code);
- }
- $_[1] = $str if $chk;
- utf8::upgrade($uni);
- return $uni;
+ my ($str) = @_;
+ utf8::encode($str);
+ return $str;
}
-sub encode
+sub decode_utf8
{
- my ($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;
- }
- $str .= pack('n',$x);
- }
- $_[1] = $uni if $chk;
- return $str;
+ my ($str) = @_;
+ return undef unless utf8::decode($str);
+ return $str;
}
-# switch back to Encode package in case we ever add AutoLoader
-package Encode;
+require Encode::Encoding;
+require Encode::XS;
+require Encode::Internal;
+require Encode::Unicode;
+require Encode::utf8;
+require Encode::10646_1;
+require Encode::ucs2_le;
1;
use Encode;
+
+=head2 Table of Contents
+
+Encode consists of a collection of modules which 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 defintions 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 machines 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. 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
+=head1 PERL ENCODING API
+
+=over 4
-=head2 Characteristics of an Encoding
+=item $bytes = encode(ENCODING, $string[, CHECK])
-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.
+Encodes string from Perl's internal form into I<ENCODING> and returns
+a sequence of octets. ENCODING can be either a canonical name or
+alias. For encoding names and aliases, see L</"Defining Aliases">.
+For CHECK see L</"Handling Malformed Data">.
-=head2 Types of Encodings
+For example to convert (internally UTF-8 encoded) Unicode string to
+iso-8859-1 (also known as Latin1),
-Encodings can be divided into the following types:
+ $octets = encode("iso-8859-1", $unicode);
-=over 4
+=item $string = decode(ENCODING, $bytes[, CHECK])
-=item * Fixed length 8-bit (or less) encodings.
+Decode 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 alias. For encoding names
+and aliases, see L</"Defining Aliases">. For CHECK see
+L</"Handling Malformed Data">.
-Each character is a single octet so may have a repertoire of up to
-256 characters. ASCII and iso-8859-* are typical examples.
+For example to convert ISO-8859-1 data to UTF-8:
-=item * Fixed length 16-bit encodings
+ $utf8 = decode("iso-8859-1", $latin1);
-Each character is two octets so may have a repertoire of up to
-65,536 characters. Unicode's UCS-2 is an example. Also used for
-encodings for East Asian languages.
+=item [$length =] from_to($string, FROM_ENCODING, TO_ENCODING[, CHECK])
-=item * Fixed length 32-bit encodings.
+Convert B<in-place> the data between two encodings. How did the data
+in $string originally get to be in FROM_ENCODING? Either using
+encode() or through PerlIO: See L</"Encoding and IO">.
+For encoding names and aliases, see L</"Defining Aliases">.
+For CHECK see L</"Handling Malformed Data">.
-Not really very "encoded" encodings. The Unicode code points
-are just represented as 4-octet integers. None the less because
-different architectures use different representations of integers
-(so called "endian") there at least two disctinct encodings.
+For example to convert ISO-8859-1 data to UTF-8:
-=item * Multi-byte encodings
+ from_to($data, "iso-8859-1", "utf-8");
-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.)
+and to convert it back:
-=item * "Escape" encodings.
+ from_to($data, "utf-8", "iso-8859-1");
-These encodings embed "escape sequences" into the octet sequence
-which describe how the following octets are to be interpreted.
-The iso-2022-* family is typical. Following the escape sequence
-octets are encoded by an "embedded" encoding (which will be one
-of the above types) until another escape sequence switches to
-a different "embedded" encoding.
+Note that because the conversion happens in place, the data to be
+converted cannot be a string constant, it must be a scalar variable.
-These schemes are very flexible and can handle mixed languages but are
-very complex to process (and have state).
-No escape encodings are implemented for perl yet.
+from_to() return the length of the converted string on success, undef
+otherwise.
=back
-=head2 Specifying Encodings
+=head2 Listing available encodings
-Encodings can be specified to the API described below in two ways:
+ use Encode;
+ @list = Encode->encodings();
-=over 4
+Returns a list of the canonical names of the available encodings that
+are loaded. To get a list of all available encodings including the
+ones that are not loaded yet, say
-=item 1. By name
+ @all_encodings = Encode->encodings(":all");
-Encoding names are strings with characters taken from a restricted repertoire.
-See L</"Encoding Names">.
+Or you can give the name of specific module.
-=item 2. As an object
+ @with_jp = Encode->encodings("Encode/JP.pm");
-Encoding objects are returned by C<find_encoding($name)>.
+Note in this case you have to say C<"Encode/JP.pm"> instead of
+C<"Encode::JP">.
-=back
+To find which encodings are supported by this package in details,
+see L<Encode::Supported>.
-=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:
+=head2 Defining Aliases
-=over 4
+To add new alias to a given encoding, Use;
-=item * The MIME name as defined in IETF RFC-XXXX.
+ use Encode;
+ use Encode::Alias;
+ define_alias(newName => ENCODING);
-=item * The name in the IANA registry.
+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>
-=item * The name used by the the organization that defined it.
+See L<Encode::Alias> on details.
-=back
+=head1 Encoding and IO
+
+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.
-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.
+Here is how the blind poet would modernise the encoding:
-=head1 PERL ENCODING API
+ use Encode;
+ open(my $iliad,'<:encoding(iso-8859-7)','iliad.greek');
+ open(my $utf8,'>:utf8','iliad.utf8');
+ my @epic = <$iliad>;
+ print $utf8 @epic;
+ close($utf8);
+ close($illiad);
-=head2 Generic Encoding Interface
+In addition the new IO system can also be configured to read/write
+UTF-8 encoded characters (as noted above this is efficient):
-=over 4
+ open(my $fh,'>:utf8','anything');
+ print $fh "Any \x{0021} string \N{SMILEY FACE}\n";
-=item *
+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>.
- $bytes = encode(ENCODING, $string[, CHECK])
+Once a handle is open is layers can be altered using C<binmode>.
-Encodes string from perl's internal form into I<ENCODING> and returns a
-sequence of octets.
-See L</"Handling Malformed Data">.
+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 *
+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+/>, ...).
- $string = decode(ENCODING, $bytes[, CHECK])
+You can also use PerlIO to convert larger amounts of data you don't
+want to bring into memory. For example to convert between ISO-8859-1
+(Latin 1) and UTF-8 (or UTF-EBCDIC in EBCDIC machines):
-Decode sequence of octets assumed to be in I<ENCODING> into perls internal
-form and returns the resuting string.
-See L</"Handling Malformed Data">.
+ open(F, "<:encoding(iso-8859-1)", "data.txt") or die $!;
+ open(G, ">:utf8", "data.utf") or die $!;
+ while (<F>) { print G }
-=back
+ # Could also do "print G <F>" but that would pull
+ # the whole file into memory just to write it out again.
+
+More examples:
+
+ open(my $f, "<:encoding(cp1252)")
+ open(my $g, ">:encoding(iso-8859-2)")
+ open(my $h, ">:encoding(latin9)") # iso-8859-15
-=head2 Handling Malformed Data
+See L<PerlIO> for more information.
+
+See also L<encoding> for how to change the default encoding of the
+data in your script.
+
+=head1 Handling Malformed Data
If CHECK is not set, C<undef> is returned. If the data is supposed to
-be UTF-8, an optional lexical warning (category utf8) is given.
-If CHECK is true but not a code reference, dies.
+be UTF-8, an optional lexical warning (category utf8) is given. If
+CHECK is true but not a code reference, dies.
-It would desirable to have a way to indicate that transform should use the
-encodings "replacement character" - no such mechanism is defined yet.
+It would desirable to have a way to indicate that transform should use
+the encodings "replacement character" - no such mechanism is defined yet.
It is also planned to allow I<CHECK> to be a code reference.
-This is not yet implemented as there are design issues with what its arguments
-should be and how it returns its results.
+This is not yet implemented as there are design issues with what its
+arguments should be and how it returns its results.
=over 4
=item Scheme 2
-Passed original string, and an index into it of the problem area,
-and output string so far.
-Appends what it will to output string and returns new index into
-original string.
-e.g.
+Passed original string, and an index into it of the problem area, and
+output string so far. Appends what it will to output string and
+returns new index into original string. For example:
sub fixup {
# my ($s,$i,$d) = @_;
return $_[1]+1;
}
-This scheme gives maximal control to the fixup routine but is more complicated
-to code, and may need internals of Encode to be tweaked to keep original
-string intact.
+This scheme gives maximal control to the fixup routine but is more
+complicated to code, and may need internals of Encode to be tweaked to
+keep original string intact.
=item Other Schemes
Multiple return values rather than in-place modifications.
-Index into the string could be pos($str) allowing s/\G...//.
+Index into the string could be C<pos($str)> allowing C<s/\G...//>.
=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 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 $bytes = encode_utf8($string);
- $bytes = encode_utf8($string);
-
-The characters that comprise string are encoded in perl's superset of UTF-8
+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 *
-
- $string = decode_utf8($bytes [,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 $bytes is decoded from UTF-8
+into a sequence of logical characters. Not all sequences of octets
+form valid UTF-8 encodings, so it is possible for this call to fail.
+For CHECK see L</"Handling Malformed Data">.
=back
-=head2 Other Encodings of Unicode
-
-UTF-16 is similar to UCS-2, 16 bit or 2-byte chunks.
-UCS-2 can only represent 0..0xFFFF, while UTF-16 has a "surogate pair"
-scheme which allows it to cover the whole Unicode range.
-
-Encode implements big-endian UCS-2 aliased to "iso-10646-1" as that
-happens to be the name used by that representation when used with X11 fonts.
-
-UTF-32 or UCS-4 is 32-bit or 4-byte chunks. Perl's logical characters
-can be considered as being in this form without encoding. An encoding
-to transfer strings in this form (e.g. to write them to a file) would need to
-
- pack('L',map(chr($_),split(//,$string))); # native
- or
- pack('V',map(chr($_),split(//,$string))); # little-endian
- or
- pack('N',map(chr($_),split(//,$string))); # big-endian
+=head1 Defining Encodings
-depending on the endian required.
+To define a new encoding, use:
-No UTF-32 encodings are implemented yet.
+ use Encode qw(define_alias);
+ define_encoding($object, 'canonicalName' [, alias...]);
-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.
-
-=head2 Listing available encodings
-
- use Encode qw(encodings);
- @list = encodings();
-
-Returns a list of the canonical names of the available encodings.
-
-=head2 Defining Aliases
-
- use Encode qw(define_alias);
- define_alias( newName => ENCODING);
-
-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).
-
-Currently I<newName> can be specified in the following ways:
-
-=over 4
-
-=item As a simple string.
-
-=item As a qr// compiled regular expression, e.g.:
-
- define_alias( qr/^iso8859-(\d+)$/i => '"iso-8859-$1"' );
-
-In this case if I<ENCODING> is not a reference it is C<eval>-ed to allow
-C<$1> etc. to be subsituted.
-The example is one way to names as used in X11 font names to alias the MIME names for the
-iso-8859-* family.
-
-=item As a code reference, e.g.:
-
- define_alias( sub { return /^iso8859-(\d+)$/i ? "iso-8859-$1" : undef } , '');
-
-In this case C<$_> 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.
-
-=back
-
-=head2 Defining Encodings
-
- use Encode qw(define_alias);
- define_encoding( $object, 'canonicalName' [,alias...]);
-
-Causes I<canonicalName> to be associated with I<$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 Encoding and IO
-
-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.
-
- open(my $ilyad,'>:encoding(iso-8859-7)','ilyad.greek');
- print $ilyad @epic;
-
-In addition the new IO system can also be configured to read/write
-UTF-8 encoded characters (as noted above this is efficient):
-
- open(my $fh,'>:utf8','anything');
- print $fh "Any \x{0021} string \N{SMILEY FACE}\n";
-
-Either of the above forms of "layer" specifications can be made the default
-for a lexical scope with the C<use open ...> pragma. See L<open>.
-
-Once a handle is open is layers can be altered using C<binmode>.
-
-Without any such configuration, or if perl itself is built using
-system's own IO, then write operations assume that file handle accepts
-only I<bytes> and will C<die> if a character larger than 255 is
-written to the handle. When reading, each octet from the handle
-becomes a byte-in-a-character. Note that this default is the same
-behaviour as bytes-only languages (including perl before v5.6) would have,
-and is sufficient to handle native 8-bit encodings e.g. iso-8859-1,
-EBCDIC etc. and any legacy mechanisms for handling other encodings
-and binary data.
-
-In other cases it is the programs responsibility
-to transform characters into bytes using the API above before
-doing writes, and to transform the bytes read from a handle into characters
-before doing "character operations" (e.g. C<lc>, C</\W+/>, ...).
-
-=head1 Encoding How to ...
-
-To do:
-
-=over 4
-
-=item * IO with mixed content (faking iso-2020-*)
-
-=item * MIME's Content-Length:
-
-=item * UTF-8 strings in binary data.
-
-=item * perl/Encode wrappers on non-Unicode XS modules.
-
-=back
+I<canonicalName> will be associated with I<$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>.
=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 * is_utf8(STRING [, CHECK])
+=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)
+If CHECK is true, also checks the data in STRING for being well-formed
+UTF-8. Returns true if successful, false otherwise.
-[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 *
-
- _utf8_on(STRING)
+=item _utf8_on(STRING)
[INTERNAL] Turn 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
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 *
-
- _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
=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>
+L<Encode::Encoding>,
+L<Encode::Supported>,
+L<PerlIO>,
+L<encoding>,
+L<perlebcdic>,
+L<perlfunc/open>,
+L<perlunicode>,
+L<utf8>,
+the Perl Unicode Mailing List E<lt>perl-unicode@perl.orgE<gt>
=cut
-
-
-
https://perl5.git.perl.org / perl5.git / blobdiff