source: gsdl/trunk/perllib/unicode.pm@ 18245

Last change on this file since 18245 was 18245, checked in by kjdon, 15 years ago

added no strict refs as we are calling a method using a string as a subroutine reference
  • Property svn:executable set to *
  • Property svn:keywords set to Author Date Id Revision
File size: 17.4 KB
Line 
1###########################################################################
2#
3# unicode.pm --
4# A component of the Greenstone digital library software
5# from the New Zealand Digital Library Project at the
6# University of Waikato, New Zealand.
7#
8# Copyright (C) 1999-2004 New Zealand Digital Library Project
9#
10# This program is free software; you can redistribute it and/or modify
11# it under the terms of the GNU General Public License as published by
12# the Free Software Foundation; either version 2 of the License, or
13# (at your option) any later version.
14#
15# This program is distributed in the hope that it will be useful,
16# but WITHOUT ANY WARRANTY; without even the implied warranty of
17# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18# GNU General Public License for more details.
19#
20# You should have received a copy of the GNU General Public License
21# along with this program; if not, write to the Free Software
22# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23#
24###########################################################################
25
26# useful functions for dealing with Unicode
27
28# Unicode strings are stored as arrays of scalars as perl
29# lacks characters are 8-bit (currently)
30
31package unicode;
32
33eval {require bytes};
34
35use encodings;
36use strict;
37use util;
38
39no strict 'refs';
40
41# ascii2unicode takes an (extended) ascii string (ISO-8859-1)
42# and returns a unicode array.
43sub ascii2unicode {
44 my ($in) = @_;
45 my $out = [];
46
47 my $i = 0;
48 my $len = length($in);
49 while ($i < $len) {
50 push (@$out, ord(substr ($in, $i, 1)));
51 $i++;
52 }
53
54 return $out;
55}
56
57# ascii2utf8 takes a reference to an (extended) ascii string and returns a
58# UTF-8 encoded string. This is just a faster version of
59# "&unicode2utf8(&ascii2unicode($str));"
60# "Extended ascii" really means "iso_8859_1"
61sub ascii2utf8 {
62 my ($in) = @_;
63 my $out = "";
64
65 if (!defined($in)|| !defined($$in)) {
66 return $out;
67 }
68
69 my ($c);
70 my $i = 0;
71 my $len = length($$in);
72 while ($i < $len) {
73 $c = ord (substr ($$in, $i, 1));
74 if ($c < 0x80) {
75 # ascii character
76 $out .= chr ($c);
77
78 } else {
79 # extended ascii character
80 $out .= chr (0xc0 + (($c >> 6) & 0x1f));
81 $out .= chr (0x80 + ($c & 0x3f));
82 }
83 $i++;
84 }
85
86 return $out;
87}
88
89# unicode2utf8 takes a unicode array as input and encodes it
90# using utf-8
91sub unicode2utf8 {
92 my ($in) = @_;
93 my $out = "";
94
95 foreach my $num (@$in) {
96 next unless defined $num;
97 if ($num < 0x80) {
98 $out .= chr ($num);
99
100 } elsif ($num < 0x800) {
101 $out .= chr (0xc0 + (($num >> 6) & 0x1f));
102 $out .= chr (0x80 + ($num & 0x3f));
103
104 } elsif ($num < 0xFFFF) {
105 $out .= chr (0xe0 + (($num >> 12) & 0xf));
106 $out .= chr (0x80 + (($num >> 6) & 0x3f));
107 $out .= chr (0x80 + ($num & 0x3f));
108
109 } else {
110 # error, don't encode anything
111 die;
112 }
113 }
114 return $out;
115}
116
117# utf82unicode takes a utf-8 string and produces a unicode
118# array
119sub utf82unicode {
120 my ($in) = @_;
121 my $out = [];
122
123 my $i = 0;
124 my ($c1, $c2, $c3);
125 my $len = length($in);
126 while ($i < $len) {
127 if (($c1 = ord(substr ($in, $i, 1))) < 0x80) {
128 # normal ascii character
129 push (@$out, $c1);
130
131 } elsif ($c1 < 0xc0) {
132 # error, was expecting the first byte of an
133 # encoded character. Do nothing.
134
135 } elsif ($c1 < 0xe0 && $i+1 < $len) {
136 # an encoded character with two bytes
137 $c2 = ord (substr ($in, $i+1, 1));
138 if ($c2 >= 0x80 && $c2 < 0xc0) {
139 # everything looks ok
140 push (@$out, ((($c1 & 0x1f) << 6) +
141 ($c2 & 0x3f)));
142 $i++; # gobbled an extra byte
143 }
144
145 } elsif ($c1 < 0xf0 && $i+2 < $len) {
146 # an encoded character with three bytes
147 $c2 = ord (substr ($in, $i+1, 1));
148 $c3 = ord (substr ($in, $i+2, 1));
149 if ($c2 >= 0x80 && $c2 < 0xc0 &&
150 $c3 >= 0x80 && $c3 < 0xc0) {
151 # everything looks ok
152 push (@$out, ((($c1 & 0xf) << 12) +
153 (($c2 & 0x3f) << 6) +
154 ($c3 & 0x3f)));
155
156 $i += 2; # gobbled an extra two bytes
157 }
158
159 } else {
160 # error, only decode Unicode characters not full UCS.
161 # Do nothing.
162 }
163
164 $i++;
165 }
166
167 return $out;
168}
169
170# unicode2ucs2 takes a unicode array and produces a UCS-2
171# unicode string (every two bytes forms a unicode character)
172sub unicode2ucs2 {
173 my ($in) = @_;
174 my $out = "";
175
176 foreach my $num (@$in) {
177 $out .= chr (($num & 0xff00) >> 8);
178 $out .= chr ($num & 0xff);
179 }
180
181 return $out;
182}
183
184# ucs22unicode takes a UCS-2 string and produces a unicode array
185sub ucs22unicode {
186 my ($in) = @_;
187 my $out = [];
188
189 my $i = 0;
190 my $len = length ($in);
191 while ($i+1 < $len) {
192 push (@$out, ord (substr($in, $i, 1)) << 8 +
193 ord (substr($in, $i+1, 1)));
194
195 $i ++;
196 }
197
198 return $out;
199}
200
201# takes a reference to a string and returns a reference to a unicode array
202sub convert2unicode {
203 my ($encoding, $textref) = @_;
204
205 if (!defined $encodings::encodings->{$encoding}) {
206 print STDERR "unicode::convert2unicode: ERROR: Unsupported encoding ($encoding)\n";
207 return [];
208 }
209
210 my $encodename = "$encoding-unicode";
211 my $enc_info = $encodings::encodings->{$encoding};
212 my $mapfile = &util::filename_cat($ENV{'GSDLHOME'}, "mappings",
213 "to_uc", $enc_info->{'mapfile'});
214 if (!&loadmapencoding ($encodename, $mapfile)) {
215 print STDERR "unicode: ERROR - could not load encoding $encodename: $! $mapfile\n";
216 return [];
217 }
218
219 if (defined $enc_info->{'converter'}) {
220 my $converter = $enc_info->{'converter'};
221 return &$converter ($encodename, $textref);
222 }
223
224 if ($unicode::translations{$encodename}->{'count'} == 1) {
225 return &singlebyte2unicode ($encodename, $textref);
226 } else {
227 return &doublebyte2unicode ($encodename, $textref);
228 }
229}
230
231# singlebyte2unicode converts simple 8 bit encodings where characters below
232# 0x80 are normal ascii characters and the rest are decoded using the
233# appropriate mapping files.
234#
235# Examples of encodings that may be converted using singlebyte2unicode are
236# the iso-8859 and windows-125* series.
237sub singlebyte2unicode {
238 my ($encodename, $textref) = @_;
239
240 my @outtext = ();
241 my $len = length($$textref);
242 my ($c);
243 my $i = 0;
244
245 while ($i < $len) {
246 if (($c = ord(substr($$textref, $i, 1))) < 0x80) {
247 # normal ascii character
248 push (@outtext, $c);
249 } else {
250 $c = &transchar ($encodename, $c);
251 # put a black square if cannot translate
252 $c = 0x25A1 if $c == 0;
253 push (@outtext, $c);
254 }
255 $i ++;
256 }
257 return \@outtext;
258}
259
260# doublebyte2unicode converts simple two byte encodings where characters
261# below code point 0x80 are single-byte characters and the rest are
262# double-byte characters.
263#
264# Examples of encodings that may be converted using doublebyte2unicode are
265# CJK encodings like GB encoded Chinese and UHC Korean.
266#
267# Note that no error checking is performed to make sure that the input text
268# is valid for the given encoding.
269#
270# Also, encodings that may contain characters of more than two bytes are
271# not supported (any EUC encoded text may in theory contain 3-byte
272# characters but in practice only one and two byte characters are used).
273sub doublebyte2unicode {
274 my ($encodename, $textref) = @_;
275
276 my @outtext = ();
277 my $len = length($$textref);
278 my ($c1, $c2);
279 my $i = 0;
280
281 while ($i < $len) {
282 if (($c1 = ord(substr($$textref, $i, 1))) >= 0x80) {
283 if ($i+1 < $len) {
284 # double-byte character
285 $c2 = ord(substr($$textref, $i+1, 1));
286 my $c = &transchar ($encodename, ($c1 << 8) | $c2);
287 # put a black square if cannot translate
288 $c = 0x25A1 if $c == 0;
289 push (@outtext, $c);
290 $i += 2;
291
292 } else {
293 # error
294 print STDERR "unicode: ERROR missing second half of double-byte character\n";
295 $i++;
296 }
297
298 } else {
299 # single-byte character
300 push (@outtext, $c1);
301 $i++;
302 }
303 }
304 return \@outtext;
305}
306
307# Shift-JIS to unicode
308# We can't use doublebyte2unicode for Shift-JIS because it uses some
309# single-byte characters above code point 0x80 (i.e. half-width katakana
310# characters in the range 0xA1-0xDF)
311sub shiftjis2unicode {
312 my ($encodename, $textref) = @_;
313
314 my @outtext = ();
315 my $len = length($$textref);
316 my ($c1, $c2);
317 my $i = 0;
318
319 while ($i < $len) {
320 $c1 = ord(substr($$textref, $i, 1));
321
322 if (($c1 >= 0xA1 && $c1 <= 0xDF) || $c1 == 0x5c || $c1 == 0x7E) {
323 # Single-byte half-width katakana character or
324 # JIS Roman yen or overline characters
325 my $c = &transchar ($encodename, $c1);
326 # - put a black square if cannot translate
327 $c = 0x25A1 if $c == 0;
328 push (@outtext, $c);
329 $i++;
330
331 } elsif ($c1 < 0x80) {
332 # ASCII
333 push (@outtext, $c1);
334 $i ++;
335
336 } elsif ($c1 < 0xEF) {
337 if ($i+1 < $len) {
338 $c2 = ord(substr($$textref, $i+1, 1));
339 if (($c2 >= 0x40 && $c2 <= 0x7E) || ($c2 >= 0x80 && $c2 <= 0xFC)) {
340 # Double-byte shift-jis character
341 my $c = &transchar ($encodename, ($c1 << 8) | $c2);
342 # put a black square if cannot translate
343 $c = 0x25A1 if $c == 0;
344 push (@outtext, $c);
345 } else {
346 # error
347 print STDERR "unicode: ERROR Invalid Shift-JIS character\n";
348 }
349 $i += 2;
350 } else {
351 # error
352 print STDERR "unicode: ERROR missing second half of Shift-JIS character\n";
353 $i ++;
354 }
355 } else {
356 # error
357 print STDERR "unicode: ERROR Invalid Shift-JIS character\n";
358 $i ++;
359 }
360 }
361 return \@outtext;
362}
363
364sub transchar {
365 my ($encoding, $from) = @_;
366 my $high = ($from / 256) % 256;
367 my $low = $from % 256;
368
369 return 0 unless defined $unicode::translations{$encoding};
370
371 my $block = $unicode::translations{$encoding}->{'map'};
372
373 if (ref ($block->[$high]) ne "ARRAY") {
374 return 0;
375 }
376 return $block->[$high]->[$low];
377}
378
379# %translations is of the form:
380#
381# encodings{encodingname-encodingname}->{'map'}->blocktranslation
382# blocktranslation->[[0-255],[256-511], ..., [65280-65535]]
383#
384# Any of the top translation blocks can point to an undefined
385# value. This data structure aims to allow fast translation and
386# efficient storage.
387%unicode::translations = ();
388
389# @array256 is used for initialisation, there must be
390# a better way...
391# What about this?: @array256 = (0) x 256;
392@unicode::array256 = (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
393 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
394 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
395 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
396 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
397 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
398 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
399 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
400 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
401 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
402 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
403 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
404 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
405 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
406 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
407 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0);
408
409# returns 1 if successful, 0 if unsuccessful
410sub loadmapencoding {
411 my ($encoding, $mapfile) = @_;
412
413 # check to see if the encoding has already been loaded
414 return 1 if (defined $unicode::translations{$encoding});
415
416 if (! -r $mapfile || -d $mapfile) {
417 return 0;
418 }
419 return 0 unless open (MAPFILE, $mapfile);
420 binmode (MAPFILE);
421
422 $unicode::translations{$encoding} = {'map' => [@unicode::array256], 'count' => 0};
423 my $block = $unicode::translations{$encoding};
424
425 my ($in,$i,$j);
426 while (1) {
427 my $ret=read(MAPFILE, $in, 1);
428 if (!defined($ret)) { # error
429 print STDERR "unicode.pm: error reading mapfile: $!\n";
430 last;
431 }
432 if ($ret != 1) { last }
433 $i = unpack ("C", $in);
434 $block->{'map'}->[$i] = [@unicode::array256];
435 for ($j=0; $j<256 && read(MAPFILE, $in, 2)==2; $j++) {
436 my ($n1, $n2) = unpack ("CC", $in);
437 $block->{'map'}->[$i]->[$j] = ($n1*256) + $n2;
438 }
439 $block->{'count'} ++;
440 }
441
442 close (MAPFILE);
443}
444
445# unicode2singlebyte converts unicode to simple 8 bit encodings where
446# characters below 0x80 are normal ascii characters and the rest are encoded
447# using the appropriate mapping files.
448#
449# Examples of encodings that may be converted using unicode2singlebyte are
450# the iso-8859 and windows-125* series, KOI8-R (Russian), and the Kazakh encoding.
451sub unicode2singlebyte {
452 my ($uniref, $encoding) = @_;
453
454 my $outtext = "";
455 my $encodename = "unicode-$encoding";
456
457 if (!exists $encodings::encodings->{$encoding}) {
458 print STDERR "unicode.pm: ERROR - unsupported encoding "
459 . "'$encoding' requested\n";
460 return "";
461 }
462
463 my $enc_info = $encodings::encodings->{$encoding};
464 my $mapfile = &util::filename_cat($ENV{'GSDLHOME'}, "mappings",
465 "from_uc", $enc_info->{'mapfile'});
466 if (!&loadmapencoding ($encodename, $mapfile)) {
467 print STDERR "unicode: ERROR - could not load encoding $encodename: $! $mapfile\n";
468 return "";
469 }
470
471 foreach my $c (@$uniref) {
472 if ($c < 0x80) {
473 # normal ascii character
474 $outtext .= chr($c);
475 } else {
476 # extended ascii character
477 $c = &transchar ($encodename, $c);
478
479 # put a question mark if cannot translate
480 if ($c == 0) {
481 $outtext .= "?";
482 } else {
483 $outtext .= chr($c);
484 }
485 }
486 }
487 return $outtext;
488}
489
490
491# this makes sure that the referenced input string is utf8 encoded, and
492# will change/remove bytes that aren't.
493# returns 0 if the text was already utf8, or 1 if text modified to become utf8
494sub ensure_utf8 {
495 my $stringref=shift;
496
497 if (!defined($stringref) || ref($stringref) ne 'SCALAR') {
498 return $stringref;
499 }
500
501 my $value=$$stringref;
502
503 my $non_utf8_found = 0;
504 $value =~ m/^/g; # to set \G
505 while ($value =~ m!\G.*?([\x80-\xff]+)!sg) {
506 my $highbytes=$1;
507 my $highbyteslength=length($highbytes);
508 # make sure this block of high bytes is utf-8
509 $highbytes =~ /^/g; # set pos()
510 my $byte_replaced = 0;
511 while ($highbytes =~
512 m!\G (?: [\xc0-\xdf][\x80-\xbf] | # 2 byte utf-8
513 [\xe0-\xef][\x80-\xbf]{2} | # 3 byte
514 [\xf0-\xf7][\x80-\xbf]{3} | # 4 byte
515 [\xf8-\xfb][\x80-\xbf]{4} | # 5 byte
516 [\xfc-\xfd][\x80-\xbf]{5} | # 6 byte
517 )*([\x80-\xff])? !xg
518 ) {
519 # this highbyte is "out-of-place" for valid utf-8
520 my $badbyte=$1;
521 if (!defined $badbyte) {next} # hit end of string
522 my $pos=pos($highbytes);
523 # replace bad byte. assume iso-8859-1 -> utf-8
524 # ascii2utf8 does "extended ascii"... ie iso-8859-1
525 my $replacement=&unicode::ascii2utf8(\$badbyte);
526 substr($highbytes, $pos-1, 1, $replacement);
527 # update the position to continue searching (for \G)
528 pos($highbytes) = $pos+length($replacement)-1;
529 $byte_replaced = 1;
530 }
531 if ($byte_replaced) {
532 # replace this block of high bytes in the $value
533 $non_utf8_found = 1;
534 my $replength=length($highbytes); # we've changed the length
535 my $textpos=pos($value); # pos at end of last match
536 # replace bad bytes with good bytes
537 substr($value, $textpos-$highbyteslength,
538 $highbyteslength, $highbytes);
539 # update the position to continue searching (for \G)
540 pos($value)=$textpos+($replength-$highbyteslength)+1;
541 }
542 }
543
544 $$stringref = $value;
545 return $non_utf8_found;
546}
547
548# Returns true (1) if the given string is utf8 and false (0) if it isn't.
549# Does not modify the string parameter.
550sub check_is_utf8 {
551 my $value=shift;
552
553 if (!defined($value)) {
554 return 0; # not utf8 because it is undefined
555 }
556
557 $value =~ m/^/g; # to set \G
558 while ($value =~ m!\G.*?([\x80-\xff]+)!sg) {
559 my $highbytes=$1;
560 # make sure this block of high bytes is utf-8
561 $highbytes =~ /^/g; # set pos()
562 while ($highbytes =~
563 m!\G (?: [\xc0-\xdf][\x80-\xbf] | # 2 byte utf-8
564 [\xe0-\xef][\x80-\xbf]{2} | # 3 byte
565 [\xf0-\xf7][\x80-\xbf]{3} | # 4 byte
566 [\xf8-\xfb][\x80-\xbf]{4} | # 5 byte
567 [\xfc-\xfd][\x80-\xbf]{5} | # 6 byte
568 )*([\x80-\xff])? !xg
569 ) {
570 my $badbyte=$1;
571 if (defined $badbyte) { # not end of string
572 return 0; # non-utf8 found
573 }
574 }
575 }
576
577 return 1;
578}
579
580sub url_encode {
581 my ($text) = @_;
582 if (!&is_url_encoded($text)) {
583 $text =~ s/([^A-Z0-9\ \.\-\_])/sprintf("%%%02X", ord($1))/iseg;
584 }
585 return $text;
586}
587
588sub url_decode {
589 my ($text) = @_;
590
591 $text =~ s/\%([A-F0-9]{2})/pack('C', hex($1))/ige;
592 return $text;
593}
594
595sub is_url_encoded {
596 my ($text) = @_;
597 return ($text =~ m/\%([A-F0-9]{2})/);
598}
599
600# When a filename on the filesystem is already URL-encoded, the
601# URL to it will have %25s in in place of every % sign, so that
602# URLs in html pages can refer to the URL-encoded filename.
603# This method changes the URL reference back into the actual
604# (URL-encoded) filename on the filesystem by replacing %25 with %.
605sub url_to_filename {
606 my ($text) =@_;
607 $text =~ s/%25/%/g;
608 return $text;
609}
610
611# When a filename on the filesystem is already URL-encoded, the
612# URL to it will have %25s in in place of every % sign, so that
613# URLs in html pages can refer to the URL-encoded filename.
614# Given a (URL-encoded) filename on the filesystem, this subroutine
615# returns the URL reference string for it by replacing % with %25.
616# The output string will be the same as the input string if the input
617# already contains one or more %25s. This is to prevent processing
618# a url more than once this way.
619sub filename_to_url {
620 my ($text) =@_;
621
622 if($text !~ m/%25/) {
623 $text =~ s/%/%25/g;
624 }
625 return $text;
626}
627
628
629sub substr
630{
631 my ($utf8_string, $offset, $length) = @_;
632
633 my @unicode_string = @{&utf82unicode($utf8_string)};
634 my $unicode_string_length = scalar(@unicode_string);
635
636 my $substr_start = $offset;
637 if ($substr_start >= $unicode_string_length) {
638 return "";
639 }
640
641 my $substr_end = $offset + $length - 1;
642 if ($substr_end >= $unicode_string_length) {
643 $substr_end = $unicode_string_length - 1;
644 }
645
646 my @unicode_substring = @unicode_string[$substr_start..$substr_end];
647 return &unicode2utf8(\@unicode_substring);
648}
649
650
6511;
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