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Diffstat (limited to 'chromium/third_party/cygwin/lib/perl5/5.10/i686-cygwin/Encode.pm')
| -rw-r--r-- | chromium/third_party/cygwin/lib/perl5/5.10/i686-cygwin/Encode.pm | 948 |
1 files changed, 0 insertions, 948 deletions
diff --git a/chromium/third_party/cygwin/lib/perl5/5.10/i686-cygwin/Encode.pm b/chromium/third_party/cygwin/lib/perl5/5.10/i686-cygwin/Encode.pm deleted file mode 100644 index 24a544a7a02..00000000000 --- a/chromium/third_party/cygwin/lib/perl5/5.10/i686-cygwin/Encode.pm +++ /dev/null @@ -1,948 +0,0 @@ -# -# $Id: Encode.pm,v 2.25 2008/05/07 20:56:05 dankogai Exp dankogai $ -# -package Encode; -use strict; -use warnings; -our $VERSION = sprintf "%d.%02d", q$Revision: 2.25 $ =~ /(\d+)/g; -sub DEBUG () { 0 } -use XSLoader (); -XSLoader::load( __PACKAGE__, $VERSION ); - -require Exporter; -use base qw/Exporter/; - -# Public, encouraged API is exported by default - -our @EXPORT = qw( - decode decode_utf8 encode encode_utf8 str2bytes bytes2str - encodings find_encoding clone_encoding -); -our @FB_FLAGS = qw( - DIE_ON_ERR WARN_ON_ERR RETURN_ON_ERR LEAVE_SRC - PERLQQ HTMLCREF XMLCREF STOP_AT_PARTIAL -); -our @FB_CONSTS = qw( - FB_DEFAULT FB_CROAK FB_QUIET FB_WARN - FB_PERLQQ FB_HTMLCREF FB_XMLCREF -); -our @EXPORT_OK = ( - 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 ], - default => [ @EXPORT ], - fallbacks => [ @FB_CONSTS ], - fallback_all => [ @FB_CONSTS, @FB_FLAGS ], -); - -# Documentation moved after __END__ for speed - NI-S - -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; -require Encode::Config; -eval { require Encode::ConfigLocal }; - -sub encodings { - my $class = shift; - my %enc; - if ( @_ and $_[0] eq ":all" ) { - %enc = ( %Encoding, %ExtModule ); - } - else { - %enc = %Encoding; - for my $mod ( map { m/::/o ? $_ : "Encode::$_" } @_ ) { - DEBUG and warn $mod; - for my $enc ( keys %ExtModule ) { - $ExtModule{$enc} eq $mod and $enc{$enc} = $mod; - } - } - } - return sort { lc $a cmp lc $b } - grep { !/^(?:Internal|Unicode|Guess)$/o } keys %enc; -} - -sub perlio_ok { - my $obj = ref( $_[0] ) ? $_[0] : find_encoding( $_[0] ); - $obj->can("perlio_ok") and return $obj->perlio_ok(); - return 0; # safety net -} - -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; -} - -sub getEncoding { - my ( $class, $name, $skip_external ) = @_; - - ref($name) && $name->can('renew') and return $name; - exists $Encoding{$name} and return $Encoding{$name}; - my $lc = lc $name; - exists $Encoding{$lc} and return $Encoding{$lc}; - - my $oc = $class->find_alias($name); - defined($oc) and return $oc; - $lc ne $name and $oc = $class->find_alias($lc); - defined($oc) and return $oc; - - unless ($skip_external) { - if ( my $mod = $ExtModule{$name} || $ExtModule{$lc} ) { - $mod =~ s,::,/,g; - $mod .= '.pm'; - eval { require $mod; }; - exists $Encoding{$name} and return $Encoding{$name}; - } - } - return; -} - -sub find_encoding($;$) { - my ( $name, $skip_external ) = @_; - return __PACKAGE__->getEncoding( $name, $skip_external ); -} - -sub resolve_alias($) { - my $obj = find_encoding(shift); - defined $obj and return $obj->name; - return; -} - -sub clone_encoding($) { - my $obj = find_encoding(shift); - ref $obj or return; - eval { require Storable }; - $@ and return; - return Storable::dclone($obj); -} - -sub encode($$;$) { - my ( $name, $string, $check ) = @_; - return undef unless defined $string; - $string .= '' if ref $string; # stringify; - $check ||= 0; - my $enc = find_encoding($name); - unless ( defined $enc ) { - require Carp; - Carp::croak("Unknown encoding '$name'"); - } - my $octets = $enc->encode( $string, $check ); - $_[1] = $string if $check and !ref $check and !( $check & LEAVE_SRC() ); - return $octets; -} -*str2bytes = \&encode; - -sub decode($$;$) { - my ( $name, $octets, $check ) = @_; - return undef unless defined $octets; - $octets .= '' if ref $octets; - $check ||= 0; - my $enc = find_encoding($name); - unless ( defined $enc ) { - require Carp; - Carp::croak("Unknown encoding '$name'"); - } - my $string = $enc->decode( $octets, $check ); - $_[1] = $octets if $check and !ref $check and !( $check & LEAVE_SRC() ); - return $string; -} -*bytes2str = \&decode; - -sub from_to($$$;$) { - my ( $string, $from, $to, $check ) = @_; - return undef unless defined $string; - $check ||= 0; - my $f = find_encoding($from); - unless ( defined $f ) { - require Carp; - Carp::croak("Unknown encoding '$from'"); - } - my $t = find_encoding($to); - unless ( defined $t ) { - require Carp; - Carp::croak("Unknown encoding '$to'"); - } - my $uni = $f->decode($string); - $_[0] = $string = $t->encode( $uni, $check ); - return undef if ( $check && length($uni) ); - return defined( $_[0] ) ? length($string) : undef; -} - -sub encode_utf8($) { - my ($str) = @_; - utf8::encode($str); - return $str; -} - -sub decode_utf8($;$) { - my ( $str, $check ) = @_; - return $str if is_utf8($str); - if ($check) { - return decode( "utf8", $str, $check ); - } - else { - return decode( "utf8", $str ); - return $str; - } -} - -predefine_encodings(1); - -# -# This is to restore %Encoding if really needed; -# - -sub predefine_encodings { - require Encode::Encoding; - no warnings 'redefine'; - my $use_xs = shift; - if ($ON_EBCDIC) { - - # was in Encode::UTF_EBCDIC - package Encode::UTF_EBCDIC; - push @Encode::UTF_EBCDIC::ISA, 'Encode::Encoding'; - *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 { - - package Encode::Internal; - push @Encode::Internal::ISA, 'Encode::Encoding'; - *decode = sub { - my ( $obj, $str, $chk ) = @_; - utf8::upgrade($str); - $_[1] = '' if $chk; - return $str; - }; - *encode = \&decode; - $Encode::Encoding{Unicode} = - bless { Name => "Internal" } => "Encode::Internal"; - } - - { - - # was in Encode::utf8 - package Encode::utf8; - push @Encode::utf8::ISA, 'Encode::Encoding'; - - # - if ($use_xs) { - Encode::DEBUG and warn __PACKAGE__, " XS on"; - *decode = \&decode_xs; - *encode = \&encode_xs; - } - else { - Encode::DEBUG and warn __PACKAGE__, " XS off"; - *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; - }; - } - *cat_decode = sub { # ($obj, $dst, $src, $pos, $trm, $chk) - # currently ignores $chk - my ( $obj, undef, undef, $pos, $trm ) = @_; - my ( $rdst, $rsrc, $rpos ) = \@_[ 1, 2, 3 ]; - use bytes; - if ( ( my $npos = index( $$rsrc, $trm, $pos ) ) >= 0 ) { - $$rdst .= - substr( $$rsrc, $pos, $npos - $pos + length($trm) ); - $$rpos = $npos + length($trm); - return 1; - } - $$rdst .= substr( $$rsrc, $pos ); - $$rpos = length($$rsrc); - return ''; - }; - $Encode::Encoding{utf8} = - bless { Name => "utf8" } => "Encode::utf8"; - $Encode::Encoding{"utf-8-strict"} = - bless { Name => "utf-8-strict", strict_utf8 => 1 } => - "Encode::utf8"; - } -} - -1; - -__END__ - -=head1 NAME - -Encode - character encodings - -=head1 SYNOPSIS - - 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 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>). - -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 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". - -=head2 TERMINOLOGY - -=over 2 - -=item * - -I<character>: a character in the range 0..(2**32-1) (or more). -(What Perl's strings are made of.) - -=item * - -I<byte>: a character in the range 0..255 -(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. a disk file.) - -=back - -=head1 PERL ENCODING API - -=over 2 - -=item $octets = encode(ENCODING, $string [, CHECK]) - -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">. - -For example, to convert a string from Perl's internal format to -iso-8859-1 (also known as Latin1), - - $octets = encode("iso-8859-1", $string); - -B<CAVEAT>: When you run C<$octets = encode("utf8", $string)>, then -$octets B<may not be equal to> $string. Though they both contain the -same data, the UTF8 flag for $octets is B<always> off. When you -encode anything, UTF8 flag of the result is always off, even when it -contains completely valid utf8 string. See L</"The UTF8 flag"> below. - -If the $string is C<undef> then C<undef> is returned. - -=item $string = decode(ENCODING, $octets [, CHECK]) - -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">. - -For example, to convert ISO-8859-1 data to a string in Perl's internal format: - - $string = decode("iso-8859-1", $octets); - -B<CAVEAT>: When you run C<$string = decode("utf8", $octets)>, then $string -B<may not be equal to> $octets. Though they both contain the same data, -the UTF8 flag for $string is on unless $octets entirely consists of -ASCII data (or EBCDIC on EBCDIC machines). See L</"The UTF8 flag"> -below. - -If the $string is C<undef> then C<undef> is returned. - -=item [$obj =] find_encoding(ENCODING) - -Returns the I<encoding object> corresponding to ENCODING. Returns -undef if no matching ENCODING is find. - -This object is what actually does the actual (en|de)coding. - - $utf8 = decode($name, $bytes); - -is in fact - - $utf8 = do{ - $obj = find_encoding($name); - croak qq(encoding "$name" not found) unless ref $obj; - $obj->decode($bytes) - }; - -with more error checking. - -Therefore you can save time by reusing this object as follows; - - my $enc = find_encoding("iso-8859-1"); - while(<>){ - my $utf8 = $enc->decode($_); - # and do someting with $utf8; - } - -Besides C<< ->decode >> and C<< ->encode >>, other methods are -available as well. For instance, C<< -> name >> returns the canonical -name of the encoding object. - - find_encoding("latin1")->name; # iso-8859-1 - -See L<Encode::Encoding> for details. - -=item [$length =] from_to($octets, FROM_ENC, TO_ENC [, CHECK]) - -Converts B<in-place> data between two encodings. The data in $octets -must be encoded as octets and not as characters in Perl's internal -format. For example, to convert ISO-8859-1 data to Microsoft's CP1250 -encoding: - - from_to($octets, "iso-8859-1", "cp1250"); - -and to convert it back: - - from_to($octets, "cp1250", "iso-8859-1"); - -Note that because the conversion happens in place, the data to be -converted cannot be a string constant; it must be a scalar variable. - -from_to() returns the length of the converted string in octets on -success, I<undef> on error. - -B<CAVEAT>: The following operations look the same but are not quite so; - - from_to($data, "iso-8859-1", "utf8"); #1 - $data = decode("iso-8859-1", $data); #2 - -Both #1 and #2 make $data consist of a completely valid UTF-8 string -but only #2 turns UTF8 flag on. #1 is equivalent to - - $data = encode("utf8", decode("iso-8859-1", $data)); - -See L</"The UTF8 flag"> below. - -Also note that - - from_to($octets, $from, $to, $check); - -is equivalent to - - $octets = encode($to, decode($from, $octets), $check); - -Yes, it does not respect the $check during decoding. It is -deliberately done that way. If you need minute control, C<decode> -then C<encode> as follows; - - $octets = encode($to, decode($from, $octets, $check_from), $check_to); - -=item $octets = encode_utf8($string); - -Equivalent to C<$octets = encode("utf8", $string);> The characters -that comprise $string are encoded in Perl's internal format and the -result is returned as a sequence of octets. All possible -characters have a UTF-8 representation so this function cannot fail. - - -=item $string = decode_utf8($octets [, CHECK]); - -equivalent to C<$string = decode("utf8", $octets [, CHECK])>. -The sequence of octets represented by -$octets is decoded from UTF-8 into a sequence of logical -characters. Not all sequences of octets form valid UTF-8 encodings, so -it is possible for this call to fail. For CHECK, see -L</"Handling Malformed Data">. - -=back - -=head2 Listing available encodings - - use Encode; - @list = Encode->encodings(); - -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 - - @all_encodings = Encode->encodings(":all"); - -Or you can give the name of a specific module. - - @with_jp = Encode->encodings("Encode::JP"); - -When "::" is not in the name, "Encode::" is assumed. - - @ebcdic = Encode->encodings("EBCDIC"); - -To find out in detail which encodings are supported by this package, -see L<Encode::Supported>. - -=head2 Defining Aliases - -To add a new alias to a given encoding, use: - - use Encode; - use Encode::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> - -But before you do so, make sure the alias is nonexistent with -C<resolve_alias()>, which returns the canonical name thereof. -i.e. - - 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 - -resolve_alias() does not need C<use Encode::Alias>; it can be -exported via C<use Encode qw(resolve_alias)>. - -See L<Encode::Alias> for details. - -=head2 Finding IANA Character Set Registry names - -The canonical name of a given encoding does not necessarily agree with -IANA IANA Character Set Registry, commonly seen as C<< Content-Type: -text/plain; charset=I<whatever> >>. For most cases canonical names -work but sometimes it does not (notably 'utf-8-strict'). - -Therefore as of Encode version 2.21, a new method C<mime_name()> is added. - - use Encode; - my $enc = find_encoding('UTF-8'); - warn $enc->name; # utf-8-strict - warn $enc->mime_name; # UTF-8 - -See also: L<Encode::Encoding> - -=head1 Encoding via PerlIO - -If your perl supports I<PerlIO> (which is the default), you can use a -PerlIO layer to decode and encode directly via a filehandle. The -following two examples are totally identical in their functionality. - - # via PerlIO - open my $in, "<:encoding(shiftjis)", $infile or die; - open my $out, ">:encoding(euc-jp)", $outfile or die; - while(<$in>){ print $out $_; } - - # via from_to - open my $in, "<", $infile or die; - open my $out, ">", $outfile or die; - while(<$in>){ - from_to($_, "shiftjis", "euc-jp", 1); - print $out $_; - } - -Unfortunately, it may be that encodings are PerlIO-savvy. You can check -if your encoding is supported by PerlIO by calling the C<perlio_ok> -method. - - Encode::perlio_ok("hz"); # False - find_encoding("euc-cn")->perlio_ok; # True where PerlIO is available - - use Encode qw(perlio_ok); # exported upon request - perlio_ok("euc-jp") - -Fortunately, all encodings that come with Encode core are PerlIO-savvy -except for hz and ISO-2022-kr. For gory details, see -L<Encode::Encoding> and L<Encode::PerlIO>. - -=head1 Handling Malformed Data - -The optional I<CHECK> argument tells Encode what to do when it -encounters malformed data. Without CHECK, Encode::FB_DEFAULT ( == 0 ) -is assumed. - -As of version 2.12 Encode supports coderef values for CHECK. See below. - -=over 2 - -=item B<NOTE:> Not all encoding support this feature - -Some encodings ignore I<CHECK> argument. For example, -L<Encode::Unicode> ignores I<CHECK> and it always croaks on error. - -=back - -Now here is the list of I<CHECK> values available - -=over 2 - -=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. When you encode, E<lt>subcharE<gt> -will be used. When you decode the code point C<0xFFFD> is used. If -the data is supposed to be UTF-8, an optional lexical warning -(category utf8) is given. - -=item I<CHECK> = Encode::FB_CROAK ( == 1) - -If I<CHECK> is 1, methods will die on error immediately with an error -message. Therefore, when I<CHECK> is set to 1, you should trap the -error with eval{} unless you really want to let it die. - -=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, -(i.e. you are reading with a fixed-width buffer). Here is a sample -code that does exactly this: - - my $buffer = ''; my $string = ''; - while(read $fh, $buffer, 256, length($buffer)){ - $string .= decode($encoding, $buffer, Encode::FB_QUIET); - # $buffer now contains the unprocessed partial character - } - -=item I<CHECK> = Encode::FB_WARN - -This is the same as above, except that it warns on error. Handy when -you are debugging the mode above. - -=item perlqq mode (I<CHECK> = Encode::FB_PERLQQ) - -=item HTML charref mode (I<CHECK> = Encode::FB_HTMLCREF) - -=item XML charref mode (I<CHECK> = Encode::FB_XMLCREF) - -For encodings that are implemented by Encode::XS, CHECK == -Encode::FB_PERLQQ turns (en|de)code into C<perlqq> fallback mode. - -When you decode, C<\xI<HH>> will be inserted for a malformed character, -where I<HH> is the hex representation of the octet that could not be -decoded to utf8. And when you encode, C<\x{I<HHHH>}> will be inserted, -where I<HHHH> is the Unicode ID of the character that cannot be found -in the character repertoire of the encoding. - -HTML/XML character reference modes are about the same, in place of -C<\x{I<HHHH>}>, HTML uses C<&#I<NNN>;> where I<NNN> is a decimal number and -XML uses C<&#xI<HHHH>;> where I<HHHH> is the hexadecimal number. - -In Encode 2.10 or later, C<LEAVE_SRC> is also implied. - -=item The bitmask - -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)>. - - FB_DEFAULT FB_CROAK FB_QUIET FB_WARN FB_PERLQQ - DIE_ON_ERR 0x0001 X - WARN_ON_ERR 0x0002 X - RETURN_ON_ERR 0x0004 X X - LEAVE_SRC 0x0008 X - PERLQQ 0x0100 X - HTMLCREF 0x0200 - XMLCREF 0x0400 - -=back - -=over 2 - -=item Encode::LEAVE_SRC - -If the C<Encode::LEAVE_SRC> bit is not set, but I<CHECK> is, then the second -argument to C<encode()> or C<decode()> may be assigned to by the functions. If -you're not interested in this, then bitwise-or the bitmask with it. - -=back - -=head2 coderef for CHECK - -As of Encode 2.12 CHECK can also be a code reference which takes the -ord value of unmapped caharacter as an argument and returns a string -that represents the fallback character. For instance, - - $ascii = encode("ascii", $utf8, sub{ sprintf "<U+%04X>", shift }); - -Acts like FB_PERLQQ but E<lt>U+I<XXXX>E<gt> is used instead of -\x{I<XXXX>}. - -=head1 Defining Encodings - -To define a new encoding, use: - - use Encode qw(define_encoding); - define_encoding($object, 'canonicalName' [, alias...]); - -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>. - -See L<Encode::Encoding> for more details. - -=head1 The UTF8 flag - -Before the introduction of Unicode support in perl, The C<eq> operator -just compared the strings represented by two scalars. Beginning with -perl 5.8, C<eq> compares two strings with simultaneous consideration of -I<the UTF8 flag>. To explain why we made it so, I will quote page 402 of -C<Programming Perl, 3rd ed.> - -=over 2 - -=item Goal #1: - -Old byte-oriented programs should not spontaneously break on the old -byte-oriented data they used to work on. - -=item Goal #2: - -Old byte-oriented programs should magically start working on the new -character-oriented data when appropriate. - -=item Goal #3: - -Programs should run just as fast in the new character-oriented mode -as in the old byte-oriented mode. - -=item Goal #4: - -Perl should remain one language, rather than forking into a -byte-oriented Perl and a character-oriented Perl. - -=back - -Back when C<Programming Perl, 3rd ed.> was written, not even Perl 5.6.0 -was born and many features documented in the book remained -unimplemented for a long time. Perl 5.8 corrected this and the introduction -of the UTF8 flag is one of them. You can think of this perl notion as of a -byte-oriented mode (UTF8 flag off) and a character-oriented mode (UTF8 -flag on). - -Here is how Encode takes care of the UTF8 flag. - -=over 2 - -=item * - -When you encode, the resulting UTF8 flag is always off. - -=item * - -When you decode, the resulting UTF8 flag is on unless you can -unambiguously represent data. Here is the definition of -dis-ambiguity. - -After C<$utf8 = decode('foo', $octet);>, - - When $octet is... The UTF8 flag in $utf8 is - --------------------------------------------- - In ASCII only (or EBCDIC only) OFF - In ISO-8859-1 ON - In any other Encoding ON - --------------------------------------------- - -As you see, there is one exception, In ASCII. That way you can assume -Goal #1. And with Encode Goal #2 is assumed but you still have to be -careful in such cases mentioned in B<CAVEAT> paragraphs. - -This UTF8 flag is not visible in perl scripts, exactly for the same -reason you cannot (or you I<don't have to>) see if a scalar contains a -string, integer, or floating point number. But you can still peek -and poke these if you will. See the section below. - -=back - -=head2 Messing with Perl's Internals - -The following API uses parts of Perl's internals in the current -implementation. As such, they are efficient but may change. - -=over 2 - -=item is_utf8(STRING [, CHECK]) - -[INTERNAL] Tests whether the UTF8 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. - -As of perl 5.8.1, L<utf8> also has utf8::is_utf8(). - -=item _utf8_on(STRING) - -[INTERNAL] Turns on the UTF8 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 UTF8 flag (so please don't treat the return value as -indicating success or failure), or C<undef> if STRING is not a string. - -=item _utf8_off(STRING) - -[INTERNAL] Turns off the UTF8 flag in STRING. Do not use frivolously. -Returns the previous state of the UTF8 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 UTF-8 vs. utf8 vs. UTF8 - - ....We now view strings not as sequences of bytes, but as sequences - of numbers in the range 0 .. 2**32-1 (or in the case of 64-bit - computers, 0 .. 2**64-1) -- Programming Perl, 3rd ed. - -That has been the perl's notion of UTF-8 but official UTF-8 is more -strict; Its ranges is much narrower (0 .. 10FFFF), some sequences are -not allowed (i.e. Those used in the surrogate pair, 0xFFFE, et al). - -Now that is overruled by Larry Wall himself. - - From: Larry Wall <larry@wall.org> - Date: December 04, 2004 11:51:58 JST - To: perl-unicode@perl.org - Subject: Re: Make Encode.pm support the real UTF-8 - Message-Id: <20041204025158.GA28754@wall.org> - - On Fri, Dec 03, 2004 at 10:12:12PM +0000, Tim Bunce wrote: - : I've no problem with 'utf8' being perl's unrestricted uft8 encoding, - : but "UTF-8" is the name of the standard and should give the - : corresponding behaviour. - - For what it's worth, that's how I've always kept them straight in my - head. - - Also for what it's worth, Perl 6 will mostly default to strict but - make it easy to switch back to lax. - - Larry - -Do you copy? As of Perl 5.8.7, B<UTF-8> means strict, official UTF-8 -while B<utf8> means liberal, lax, version thereof. And Encode version -2.10 or later thus groks the difference between C<UTF-8> and C"utf8". - - encode("utf8", "\x{FFFF_FFFF}", 1); # okay - encode("UTF-8", "\x{FFFF_FFFF}", 1); # croaks - -C<UTF-8> in Encode is actually a canonical name for C<utf-8-strict>. -Yes, the hyphen between "UTF" and "8" is important. Without it Encode -goes "liberal" - - find_encoding("UTF-8")->name # is 'utf-8-strict' - find_encoding("utf-8")->name # ditto. names are case insensitive - find_encoding("utf_8")->name # ditto. "_" are treated as "-" - find_encoding("UTF8")->name # is 'utf8'. - -The UTF8 flag is internally called UTF8, without a hyphen. It indicates -whether a string is internally encoded as utf8, also without a hypen. - -=head1 SEE ALSO - -L<Encode::Encoding>, -L<Encode::Supported>, -L<Encode::PerlIO>, -L<encoding>, -L<perlebcdic>, -L<perlfunc/open>, -L<perlunicode>, L<perluniintro>, L<perlunifaq>, L<perlunitut> -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 we can all share. - -While Dan Kogai retains the copyright as a maintainer, the credit -should go to all those involoved. See AUTHORS for those submitted -codes. - -=head1 COPYRIGHT - -Copyright 2002-2006 Dan Kogai E<lt>dankogai@dan.co.jpE<gt> - -This library is free software; you can redistribute it and/or modify -it under the same terms as Perl itself. - -=cut |