diff options
Diffstat (limited to 'Master/tlpkg/tlperl/lib/Encode/Unicode.pm')
-rw-r--r-- | Master/tlpkg/tlperl/lib/Encode/Unicode.pm | 268 |
1 files changed, 0 insertions, 268 deletions
diff --git a/Master/tlpkg/tlperl/lib/Encode/Unicode.pm b/Master/tlpkg/tlperl/lib/Encode/Unicode.pm deleted file mode 100644 index 4d0c31d82d3..00000000000 --- a/Master/tlpkg/tlperl/lib/Encode/Unicode.pm +++ /dev/null @@ -1,268 +0,0 @@ -package Encode::Unicode; - -use strict; -use warnings; -no warnings 'redefine'; - -our $VERSION = do { my @r = (q$Revision: 2.2 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r }; - -use XSLoader; -XSLoader::load(__PACKAGE__,$VERSION); - -# -# Object Generator 8 transcoders all at once! -# - -require Encode; - -our %BOM_Unknown = map {$_ => 1} qw(UTF-16 UTF-32); - -for my $name (qw(UTF-16 UTF-16BE UTF-16LE - UTF-32 UTF-32BE UTF-32LE - UCS-2BE UCS-2LE)) -{ - my ($size, $endian, $ucs2, $mask); - $name =~ /^(\w+)-(\d+)(\w*)$/o; - if ($ucs2 = ($1 eq 'UCS')){ - $size = 2; - }else{ - $size = $2/8; - } - $endian = ($3 eq 'BE') ? 'n' : ($3 eq 'LE') ? 'v' : '' ; - $size == 4 and $endian = uc($endian); - - $Encode::Encoding{$name} = - bless { - Name => $name, - size => $size, - endian => $endian, - ucs2 => $ucs2, - } => __PACKAGE__; -} - -use base qw(Encode::Encoding); - -sub renew { - my $self = shift; - $BOM_Unknown{$self->name} or return $self; - my $clone = bless { %$self } => ref($self); - $clone->{renewed}++; # so the caller knows it is renewed. - return $clone; -} - -# There used to be a perl implemntation of (en|de)code but with -# XS version is ripe, perl version is zapped for optimal speed - -*decode = \&decode_xs; -*encode = \&encode_xs; - -1; -__END__ - -=head1 NAME - -Encode::Unicode -- Various Unicode Transformation Formats - -=cut - -=head1 SYNOPSIS - - use Encode qw/encode decode/; - $ucs2 = encode("UCS-2BE", $utf8); - $utf8 = decode("UCS-2BE", $ucs2); - -=head1 ABSTRACT - -This module implements all Character Encoding Schemes of Unicode that -are officially documented by Unicode Consortium (except, of course, -for UTF-8, which is a native format in perl). - -=over 4 - -=item L<http://www.unicode.org/glossary/> says: - -I<Character Encoding Scheme> A character encoding form plus byte -serialization. There are Seven character encoding schemes in Unicode: -UTF-8, UTF-16, UTF-16BE, UTF-16LE, UTF-32 (UCS-4), UTF-32BE (UCS-4BE) and -UTF-32LE (UCS-4LE), and UTF-7. - -Since UTF-7 is a 7-bit (re)encoded version of UTF-16BE, It is not part of -Unicode's Character Encoding Scheme. It is separately implemented in -Encode::Unicode::UTF7. For details see L<Encode::Unicode::UTF7>. - -=item Quick Reference - - Decodes from ord(N) Encodes chr(N) to... - octet/char BOM S.P d800-dfff ord > 0xffff \x{1abcd} == - ---------------+-----------------+------------------------------ - UCS-2BE 2 N N is bogus Not Available - UCS-2LE 2 N N bogus Not Available - UTF-16 2/4 Y Y is S.P S.P BE/LE - UTF-16BE 2/4 N Y S.P S.P 0xd82a,0xdfcd - UTF-16LE 2 N Y S.P S.P 0x2ad8,0xcddf - UTF-32 4 Y - is bogus As is BE/LE - UTF-32BE 4 N - bogus As is 0x0001abcd - UTF-32LE 4 N - bogus As is 0xcdab0100 - UTF-8 1-4 - - bogus >= 4 octets \xf0\x9a\af\8d - ---------------+-----------------+------------------------------ - -=back - -=head1 Size, Endianness, and BOM - -You can categorize these CES by 3 criteria: size of each character, -endianness, and Byte Order Mark. - -=head2 by size - -UCS-2 is a fixed-length encoding with each character taking 16 bits. -It B<does not> support I<surrogate pairs>. When a surrogate pair -is encountered during decode(), its place is filled with \x{FFFD} -if I<CHECK> is 0, or the routine croaks if I<CHECK> is 1. When a -character whose ord value is larger than 0xFFFF is encountered, -its place is filled with \x{FFFD} if I<CHECK> is 0, or the routine -croaks if I<CHECK> is 1. - -UTF-16 is almost the same as UCS-2 but it supports I<surrogate pairs>. -When it encounters a high surrogate (0xD800-0xDBFF), it fetches the -following low surrogate (0xDC00-0xDFFF) and C<desurrogate>s them to -form a character. Bogus surrogates result in death. When \x{10000} -or above is encountered during encode(), it C<ensurrogate>s them and -pushes the surrogate pair to the output stream. - -UTF-32 (UCS-4) is a fixed-length encoding with each character taking 32 bits. -Since it is 32-bit, there is no need for I<surrogate pairs>. - -=head2 by endianness - -The first (and now failed) goal of Unicode was to map all character -repertoires into a fixed-length integer so that programmers are happy. -Since each character is either a I<short> or I<long> in C, you have to -pay attention to the endianness of each platform when you pass data -to one another. - -Anything marked as BE is Big Endian (or network byte order) and LE is -Little Endian (aka VAX byte order). For anything not marked either -BE or LE, a character called Byte Order Mark (BOM) indicating the -endianness is prepended to the string. - -CAVEAT: Though BOM in utf8 (\xEF\xBB\xBF) is valid, it is meaningless -and as of this writing Encode suite just leave it as is (\x{FeFF}). - -=over 4 - -=item BOM as integer when fetched in network byte order - - 16 32 bits/char - ------------------------- - BE 0xFeFF 0x0000FeFF - LE 0xFFeF 0xFFFe0000 - ------------------------- - -=back - -This modules handles the BOM as follows. - -=over 4 - -=item * - -When BE or LE is explicitly stated as the name of encoding, BOM is -simply treated as a normal character (ZERO WIDTH NO-BREAK SPACE). - -=item * - -When BE or LE is omitted during decode(), it checks if BOM is at the -beginning of the string; if one is found, the endianness is set to -what the BOM says. If no BOM is found, the routine dies. - -=item * - -When BE or LE is omitted during encode(), it returns a BE-encoded -string with BOM prepended. So when you want to encode a whole text -file, make sure you encode() the whole text at once, not line by line -or each line, not file, will have a BOM prepended. - -=item * - -C<UCS-2> is an exception. Unlike others, this is an alias of UCS-2BE. -UCS-2 is already registered by IANA and others that way. - -=back - -=head1 Surrogate Pairs - -To say the least, surrogate pairs were the biggest mistake of the -Unicode Consortium. But according to the late Douglas Adams in I<The -Hitchhiker's Guide to the Galaxy> Trilogy, C<In the beginning the -Universe was created. This has made a lot of people very angry and -been widely regarded as a bad move>. Their mistake was not of this -magnitude so let's forgive them. - -(I don't dare make any comparison with Unicode Consortium and the -Vogons here ;) Or, comparing Encode to Babel Fish is completely -appropriate -- if you can only stick this into your ear :) - -Surrogate pairs were born when the Unicode Consortium finally -admitted that 16 bits were not big enough to hold all the world's -character repertoires. But they already made UCS-2 16-bit. What -do we do? - -Back then, the range 0xD800-0xDFFF was not allocated. Let's split -that range in half and use the first half to represent the C<upper -half of a character> and the second half to represent the C<lower -half of a character>. That way, you can represent 1024 * 1024 = -1048576 more characters. Now we can store character ranges up to -\x{10ffff} even with 16-bit encodings. This pair of half-character is -now called a I<surrogate pair> and UTF-16 is the name of the encoding -that embraces them. - -Here is a formula to ensurrogate a Unicode character \x{10000} and -above; - - $hi = ($uni - 0x10000) / 0x400 + 0xD800; - $lo = ($uni - 0x10000) % 0x400 + 0xDC00; - -And to desurrogate; - - $uni = 0x10000 + ($hi - 0xD800) * 0x400 + ($lo - 0xDC00); - -Note this move has made \x{D800}-\x{DFFF} into a forbidden zone but -perl does not prohibit the use of characters within this range. To perl, -every one of \x{0000_0000} up to \x{ffff_ffff} (*) is I<a character>. - - (*) or \x{ffff_ffff_ffff_ffff} if your perl is compiled with 64-bit - integer support! - -=head1 Error Checking - -Unlike most encodings which accept various ways to handle errors, -Unicode encodings simply croaks. - - % perl -MEncode -e '$_ = "\xfe\xff\xd8\xd9\xda\xdb\0\n"' \ - -e 'Encode::from_to($_, "utf16","shift_jis", 0); print' - UTF-16:Malformed LO surrogate d8d9 at /path/to/Encode.pm line 184. - % perl -MEncode -e '$a = "BOM missing"' \ - -e ' Encode::from_to($a, "utf16", "shift_jis", 0); print' - UTF-16:Unrecognised BOM 424f at /path/to/Encode.pm line 184. - -Unlike other encodings where mappings are not one-to-one against -Unicode, UTFs are supposed to map 100% against one another. So Encode -is more strict on UTFs. - -Consider that "division by zero" of Encode :) - -=head1 SEE ALSO - -L<Encode>, L<Encode::Unicode::UTF7>, L<http://www.unicode.org/glossary/>, -L<http://www.unicode.org/unicode/faq/utf_bom.html>, - -RFC 2781 L<http://rfc.net/rfc2781.html>, - -The whole Unicode standard L<http://www.unicode.org/unicode/uni2book/u2.html> - -Ch. 15, pp. 403 of C<Programming Perl (3rd Edition)> -by Larry Wall, Tom Christiansen, Jon Orwant; -O'Reilly & Associates; ISBN 0-596-00027-8 - -=cut |