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Diffstat (limited to 'inc/3rdparty/htmlpurifier/HTMLPurifier/Encoder.php')
-rw-r--r-- | inc/3rdparty/htmlpurifier/HTMLPurifier/Encoder.php | 611 |
1 files changed, 611 insertions, 0 deletions
diff --git a/inc/3rdparty/htmlpurifier/HTMLPurifier/Encoder.php b/inc/3rdparty/htmlpurifier/HTMLPurifier/Encoder.php new file mode 100644 index 00000000..3aa00ca5 --- /dev/null +++ b/inc/3rdparty/htmlpurifier/HTMLPurifier/Encoder.php | |||
@@ -0,0 +1,611 @@ | |||
1 | <?php | ||
2 | |||
3 | /** | ||
4 | * A UTF-8 specific character encoder that handles cleaning and transforming. | ||
5 | * @note All functions in this class should be static. | ||
6 | */ | ||
7 | class HTMLPurifier_Encoder | ||
8 | { | ||
9 | |||
10 | /** | ||
11 | * Constructor throws fatal error if you attempt to instantiate class | ||
12 | */ | ||
13 | private function __construct() | ||
14 | { | ||
15 | trigger_error('Cannot instantiate encoder, call methods statically', E_USER_ERROR); | ||
16 | } | ||
17 | |||
18 | /** | ||
19 | * Error-handler that mutes errors, alternative to shut-up operator. | ||
20 | */ | ||
21 | public static function muteErrorHandler() | ||
22 | { | ||
23 | } | ||
24 | |||
25 | /** | ||
26 | * iconv wrapper which mutes errors, but doesn't work around bugs. | ||
27 | * @param string $in Input encoding | ||
28 | * @param string $out Output encoding | ||
29 | * @param string $text The text to convert | ||
30 | * @return string | ||
31 | */ | ||
32 | public static function unsafeIconv($in, $out, $text) | ||
33 | { | ||
34 | set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler')); | ||
35 | $r = iconv($in, $out, $text); | ||
36 | restore_error_handler(); | ||
37 | return $r; | ||
38 | } | ||
39 | |||
40 | /** | ||
41 | * iconv wrapper which mutes errors and works around bugs. | ||
42 | * @param string $in Input encoding | ||
43 | * @param string $out Output encoding | ||
44 | * @param string $text The text to convert | ||
45 | * @param int $max_chunk_size | ||
46 | * @return string | ||
47 | */ | ||
48 | public static function iconv($in, $out, $text, $max_chunk_size = 8000) | ||
49 | { | ||
50 | $code = self::testIconvTruncateBug(); | ||
51 | if ($code == self::ICONV_OK) { | ||
52 | return self::unsafeIconv($in, $out, $text); | ||
53 | } elseif ($code == self::ICONV_TRUNCATES) { | ||
54 | // we can only work around this if the input character set | ||
55 | // is utf-8 | ||
56 | if ($in == 'utf-8') { | ||
57 | if ($max_chunk_size < 4) { | ||
58 | trigger_error('max_chunk_size is too small', E_USER_WARNING); | ||
59 | return false; | ||
60 | } | ||
61 | // split into 8000 byte chunks, but be careful to handle | ||
62 | // multibyte boundaries properly | ||
63 | if (($c = strlen($text)) <= $max_chunk_size) { | ||
64 | return self::unsafeIconv($in, $out, $text); | ||
65 | } | ||
66 | $r = ''; | ||
67 | $i = 0; | ||
68 | while (true) { | ||
69 | if ($i + $max_chunk_size >= $c) { | ||
70 | $r .= self::unsafeIconv($in, $out, substr($text, $i)); | ||
71 | break; | ||
72 | } | ||
73 | // wibble the boundary | ||
74 | if (0x80 != (0xC0 & ord($text[$i + $max_chunk_size]))) { | ||
75 | $chunk_size = $max_chunk_size; | ||
76 | } elseif (0x80 != (0xC0 & ord($text[$i + $max_chunk_size - 1]))) { | ||
77 | $chunk_size = $max_chunk_size - 1; | ||
78 | } elseif (0x80 != (0xC0 & ord($text[$i + $max_chunk_size - 2]))) { | ||
79 | $chunk_size = $max_chunk_size - 2; | ||
80 | } elseif (0x80 != (0xC0 & ord($text[$i + $max_chunk_size - 3]))) { | ||
81 | $chunk_size = $max_chunk_size - 3; | ||
82 | } else { | ||
83 | return false; // rather confusing UTF-8... | ||
84 | } | ||
85 | $chunk = substr($text, $i, $chunk_size); // substr doesn't mind overlong lengths | ||
86 | $r .= self::unsafeIconv($in, $out, $chunk); | ||
87 | $i += $chunk_size; | ||
88 | } | ||
89 | return $r; | ||
90 | } else { | ||
91 | return false; | ||
92 | } | ||
93 | } else { | ||
94 | return false; | ||
95 | } | ||
96 | } | ||
97 | |||
98 | /** | ||
99 | * Cleans a UTF-8 string for well-formedness and SGML validity | ||
100 | * | ||
101 | * It will parse according to UTF-8 and return a valid UTF8 string, with | ||
102 | * non-SGML codepoints excluded. | ||
103 | * | ||
104 | * @param string $str The string to clean | ||
105 | * @param bool $force_php | ||
106 | * @return string | ||
107 | * | ||
108 | * @note Just for reference, the non-SGML code points are 0 to 31 and | ||
109 | * 127 to 159, inclusive. However, we allow code points 9, 10 | ||
110 | * and 13, which are the tab, line feed and carriage return | ||
111 | * respectively. 128 and above the code points map to multibyte | ||
112 | * UTF-8 representations. | ||
113 | * | ||
114 | * @note Fallback code adapted from utf8ToUnicode by Henri Sivonen and | ||
115 | * hsivonen@iki.fi at <http://iki.fi/hsivonen/php-utf8/> under the | ||
116 | * LGPL license. Notes on what changed are inside, but in general, | ||
117 | * the original code transformed UTF-8 text into an array of integer | ||
118 | * Unicode codepoints. Understandably, transforming that back to | ||
119 | * a string would be somewhat expensive, so the function was modded to | ||
120 | * directly operate on the string. However, this discourages code | ||
121 | * reuse, and the logic enumerated here would be useful for any | ||
122 | * function that needs to be able to understand UTF-8 characters. | ||
123 | * As of right now, only smart lossless character encoding converters | ||
124 | * would need that, and I'm probably not going to implement them. | ||
125 | * Once again, PHP 6 should solve all our problems. | ||
126 | */ | ||
127 | public static function cleanUTF8($str, $force_php = false) | ||
128 | { | ||
129 | // UTF-8 validity is checked since PHP 4.3.5 | ||
130 | // This is an optimization: if the string is already valid UTF-8, no | ||
131 | // need to do PHP stuff. 99% of the time, this will be the case. | ||
132 | // The regexp matches the XML char production, as well as well as excluding | ||
133 | // non-SGML codepoints U+007F to U+009F | ||
134 | if (preg_match( | ||
135 | '/^[\x{9}\x{A}\x{D}\x{20}-\x{7E}\x{A0}-\x{D7FF}\x{E000}-\x{FFFD}\x{10000}-\x{10FFFF}]*$/Du', | ||
136 | $str | ||
137 | )) { | ||
138 | return $str; | ||
139 | } | ||
140 | |||
141 | $mState = 0; // cached expected number of octets after the current octet | ||
142 | // until the beginning of the next UTF8 character sequence | ||
143 | $mUcs4 = 0; // cached Unicode character | ||
144 | $mBytes = 1; // cached expected number of octets in the current sequence | ||
145 | |||
146 | // original code involved an $out that was an array of Unicode | ||
147 | // codepoints. Instead of having to convert back into UTF-8, we've | ||
148 | // decided to directly append valid UTF-8 characters onto a string | ||
149 | // $out once they're done. $char accumulates raw bytes, while $mUcs4 | ||
150 | // turns into the Unicode code point, so there's some redundancy. | ||
151 | |||
152 | $out = ''; | ||
153 | $char = ''; | ||
154 | |||
155 | $len = strlen($str); | ||
156 | for ($i = 0; $i < $len; $i++) { | ||
157 | $in = ord($str{$i}); | ||
158 | $char .= $str[$i]; // append byte to char | ||
159 | if (0 == $mState) { | ||
160 | // When mState is zero we expect either a US-ASCII character | ||
161 | // or a multi-octet sequence. | ||
162 | if (0 == (0x80 & ($in))) { | ||
163 | // US-ASCII, pass straight through. | ||
164 | if (($in <= 31 || $in == 127) && | ||
165 | !($in == 9 || $in == 13 || $in == 10) // save \r\t\n | ||
166 | ) { | ||
167 | // control characters, remove | ||
168 | } else { | ||
169 | $out .= $char; | ||
170 | } | ||
171 | // reset | ||
172 | $char = ''; | ||
173 | $mBytes = 1; | ||
174 | } elseif (0xC0 == (0xE0 & ($in))) { | ||
175 | // First octet of 2 octet sequence | ||
176 | $mUcs4 = ($in); | ||
177 | $mUcs4 = ($mUcs4 & 0x1F) << 6; | ||
178 | $mState = 1; | ||
179 | $mBytes = 2; | ||
180 | } elseif (0xE0 == (0xF0 & ($in))) { | ||
181 | // First octet of 3 octet sequence | ||
182 | $mUcs4 = ($in); | ||
183 | $mUcs4 = ($mUcs4 & 0x0F) << 12; | ||
184 | $mState = 2; | ||
185 | $mBytes = 3; | ||
186 | } elseif (0xF0 == (0xF8 & ($in))) { | ||
187 | // First octet of 4 octet sequence | ||
188 | $mUcs4 = ($in); | ||
189 | $mUcs4 = ($mUcs4 & 0x07) << 18; | ||
190 | $mState = 3; | ||
191 | $mBytes = 4; | ||
192 | } elseif (0xF8 == (0xFC & ($in))) { | ||
193 | // First octet of 5 octet sequence. | ||
194 | // | ||
195 | // This is illegal because the encoded codepoint must be | ||
196 | // either: | ||
197 | // (a) not the shortest form or | ||
198 | // (b) outside the Unicode range of 0-0x10FFFF. | ||
199 | // Rather than trying to resynchronize, we will carry on | ||
200 | // until the end of the sequence and let the later error | ||
201 | // handling code catch it. | ||
202 | $mUcs4 = ($in); | ||
203 | $mUcs4 = ($mUcs4 & 0x03) << 24; | ||
204 | $mState = 4; | ||
205 | $mBytes = 5; | ||
206 | } elseif (0xFC == (0xFE & ($in))) { | ||
207 | // First octet of 6 octet sequence, see comments for 5 | ||
208 | // octet sequence. | ||
209 | $mUcs4 = ($in); | ||
210 | $mUcs4 = ($mUcs4 & 1) << 30; | ||
211 | $mState = 5; | ||
212 | $mBytes = 6; | ||
213 | } else { | ||
214 | // Current octet is neither in the US-ASCII range nor a | ||
215 | // legal first octet of a multi-octet sequence. | ||
216 | $mState = 0; | ||
217 | $mUcs4 = 0; | ||
218 | $mBytes = 1; | ||
219 | $char = ''; | ||
220 | } | ||
221 | } else { | ||
222 | // When mState is non-zero, we expect a continuation of the | ||
223 | // multi-octet sequence | ||
224 | if (0x80 == (0xC0 & ($in))) { | ||
225 | // Legal continuation. | ||
226 | $shift = ($mState - 1) * 6; | ||
227 | $tmp = $in; | ||
228 | $tmp = ($tmp & 0x0000003F) << $shift; | ||
229 | $mUcs4 |= $tmp; | ||
230 | |||
231 | if (0 == --$mState) { | ||
232 | // End of the multi-octet sequence. mUcs4 now contains | ||
233 | // the final Unicode codepoint to be output | ||
234 | |||
235 | // Check for illegal sequences and codepoints. | ||
236 | |||
237 | // From Unicode 3.1, non-shortest form is illegal | ||
238 | if (((2 == $mBytes) && ($mUcs4 < 0x0080)) || | ||
239 | ((3 == $mBytes) && ($mUcs4 < 0x0800)) || | ||
240 | ((4 == $mBytes) && ($mUcs4 < 0x10000)) || | ||
241 | (4 < $mBytes) || | ||
242 | // From Unicode 3.2, surrogate characters = illegal | ||
243 | (($mUcs4 & 0xFFFFF800) == 0xD800) || | ||
244 | // Codepoints outside the Unicode range are illegal | ||
245 | ($mUcs4 > 0x10FFFF) | ||
246 | ) { | ||
247 | |||
248 | } elseif (0xFEFF != $mUcs4 && // omit BOM | ||
249 | // check for valid Char unicode codepoints | ||
250 | ( | ||
251 | 0x9 == $mUcs4 || | ||
252 | 0xA == $mUcs4 || | ||
253 | 0xD == $mUcs4 || | ||
254 | (0x20 <= $mUcs4 && 0x7E >= $mUcs4) || | ||
255 | // 7F-9F is not strictly prohibited by XML, | ||
256 | // but it is non-SGML, and thus we don't allow it | ||
257 | (0xA0 <= $mUcs4 && 0xD7FF >= $mUcs4) || | ||
258 | (0x10000 <= $mUcs4 && 0x10FFFF >= $mUcs4) | ||
259 | ) | ||
260 | ) { | ||
261 | $out .= $char; | ||
262 | } | ||
263 | // initialize UTF8 cache (reset) | ||
264 | $mState = 0; | ||
265 | $mUcs4 = 0; | ||
266 | $mBytes = 1; | ||
267 | $char = ''; | ||
268 | } | ||
269 | } else { | ||
270 | // ((0xC0 & (*in) != 0x80) && (mState != 0)) | ||
271 | // Incomplete multi-octet sequence. | ||
272 | // used to result in complete fail, but we'll reset | ||
273 | $mState = 0; | ||
274 | $mUcs4 = 0; | ||
275 | $mBytes = 1; | ||
276 | $char =''; | ||
277 | } | ||
278 | } | ||
279 | } | ||
280 | return $out; | ||
281 | } | ||
282 | |||
283 | /** | ||
284 | * Translates a Unicode codepoint into its corresponding UTF-8 character. | ||
285 | * @note Based on Feyd's function at | ||
286 | * <http://forums.devnetwork.net/viewtopic.php?p=191404#191404>, | ||
287 | * which is in public domain. | ||
288 | * @note While we're going to do code point parsing anyway, a good | ||
289 | * optimization would be to refuse to translate code points that | ||
290 | * are non-SGML characters. However, this could lead to duplication. | ||
291 | * @note This is very similar to the unichr function in | ||
292 | * maintenance/generate-entity-file.php (although this is superior, | ||
293 | * due to its sanity checks). | ||
294 | */ | ||
295 | |||
296 | // +----------+----------+----------+----------+ | ||
297 | // | 33222222 | 22221111 | 111111 | | | ||
298 | // | 10987654 | 32109876 | 54321098 | 76543210 | bit | ||
299 | // +----------+----------+----------+----------+ | ||
300 | // | | | | 0xxxxxxx | 1 byte 0x00000000..0x0000007F | ||
301 | // | | | 110yyyyy | 10xxxxxx | 2 byte 0x00000080..0x000007FF | ||
302 | // | | 1110zzzz | 10yyyyyy | 10xxxxxx | 3 byte 0x00000800..0x0000FFFF | ||
303 | // | 11110www | 10wwzzzz | 10yyyyyy | 10xxxxxx | 4 byte 0x00010000..0x0010FFFF | ||
304 | // +----------+----------+----------+----------+ | ||
305 | // | 00000000 | 00011111 | 11111111 | 11111111 | Theoretical upper limit of legal scalars: 2097151 (0x001FFFFF) | ||
306 | // | 00000000 | 00010000 | 11111111 | 11111111 | Defined upper limit of legal scalar codes | ||
307 | // +----------+----------+----------+----------+ | ||
308 | |||
309 | public static function unichr($code) | ||
310 | { | ||
311 | if ($code > 1114111 or $code < 0 or | ||
312 | ($code >= 55296 and $code <= 57343) ) { | ||
313 | // bits are set outside the "valid" range as defined | ||
314 | // by UNICODE 4.1.0 | ||
315 | return ''; | ||
316 | } | ||
317 | |||
318 | $x = $y = $z = $w = 0; | ||
319 | if ($code < 128) { | ||
320 | // regular ASCII character | ||
321 | $x = $code; | ||
322 | } else { | ||
323 | // set up bits for UTF-8 | ||
324 | $x = ($code & 63) | 128; | ||
325 | if ($code < 2048) { | ||
326 | $y = (($code & 2047) >> 6) | 192; | ||
327 | } else { | ||
328 | $y = (($code & 4032) >> 6) | 128; | ||
329 | if ($code < 65536) { | ||
330 | $z = (($code >> 12) & 15) | 224; | ||
331 | } else { | ||
332 | $z = (($code >> 12) & 63) | 128; | ||
333 | $w = (($code >> 18) & 7) | 240; | ||
334 | } | ||
335 | } | ||
336 | } | ||
337 | // set up the actual character | ||
338 | $ret = ''; | ||
339 | if ($w) { | ||
340 | $ret .= chr($w); | ||
341 | } | ||
342 | if ($z) { | ||
343 | $ret .= chr($z); | ||
344 | } | ||
345 | if ($y) { | ||
346 | $ret .= chr($y); | ||
347 | } | ||
348 | $ret .= chr($x); | ||
349 | |||
350 | return $ret; | ||
351 | } | ||
352 | |||
353 | /** | ||
354 | * @return bool | ||
355 | */ | ||
356 | public static function iconvAvailable() | ||
357 | { | ||
358 | static $iconv = null; | ||
359 | if ($iconv === null) { | ||
360 | $iconv = function_exists('iconv') && self::testIconvTruncateBug() != self::ICONV_UNUSABLE; | ||
361 | } | ||
362 | return $iconv; | ||
363 | } | ||
364 | |||
365 | /** | ||
366 | * Convert a string to UTF-8 based on configuration. | ||
367 | * @param string $str The string to convert | ||
368 | * @param HTMLPurifier_Config $config | ||
369 | * @param HTMLPurifier_Context $context | ||
370 | * @return string | ||
371 | */ | ||
372 | public static function convertToUTF8($str, $config, $context) | ||
373 | { | ||
374 | $encoding = $config->get('Core.Encoding'); | ||
375 | if ($encoding === 'utf-8') { | ||
376 | return $str; | ||
377 | } | ||
378 | static $iconv = null; | ||
379 | if ($iconv === null) { | ||
380 | $iconv = self::iconvAvailable(); | ||
381 | } | ||
382 | if ($iconv && !$config->get('Test.ForceNoIconv')) { | ||
383 | // unaffected by bugs, since UTF-8 support all characters | ||
384 | $str = self::unsafeIconv($encoding, 'utf-8//IGNORE', $str); | ||
385 | if ($str === false) { | ||
386 | // $encoding is not a valid encoding | ||
387 | trigger_error('Invalid encoding ' . $encoding, E_USER_ERROR); | ||
388 | return ''; | ||
389 | } | ||
390 | // If the string is bjorked by Shift_JIS or a similar encoding | ||
391 | // that doesn't support all of ASCII, convert the naughty | ||
392 | // characters to their true byte-wise ASCII/UTF-8 equivalents. | ||
393 | $str = strtr($str, self::testEncodingSupportsASCII($encoding)); | ||
394 | return $str; | ||
395 | } elseif ($encoding === 'iso-8859-1') { | ||
396 | $str = utf8_encode($str); | ||
397 | return $str; | ||
398 | } | ||
399 | $bug = HTMLPurifier_Encoder::testIconvTruncateBug(); | ||
400 | if ($bug == self::ICONV_OK) { | ||
401 | trigger_error('Encoding not supported, please install iconv', E_USER_ERROR); | ||
402 | } else { | ||
403 | trigger_error( | ||
404 | 'You have a buggy version of iconv, see https://bugs.php.net/bug.php?id=48147 ' . | ||
405 | 'and http://sourceware.org/bugzilla/show_bug.cgi?id=13541', | ||
406 | E_USER_ERROR | ||
407 | ); | ||
408 | } | ||
409 | } | ||
410 | |||
411 | /** | ||
412 | * Converts a string from UTF-8 based on configuration. | ||
413 | * @param string $str The string to convert | ||
414 | * @param HTMLPurifier_Config $config | ||
415 | * @param HTMLPurifier_Context $context | ||
416 | * @return string | ||
417 | * @note Currently, this is a lossy conversion, with unexpressable | ||
418 | * characters being omitted. | ||
419 | */ | ||
420 | public static function convertFromUTF8($str, $config, $context) | ||
421 | { | ||
422 | $encoding = $config->get('Core.Encoding'); | ||
423 | if ($escape = $config->get('Core.EscapeNonASCIICharacters')) { | ||
424 | $str = self::convertToASCIIDumbLossless($str); | ||
425 | } | ||
426 | if ($encoding === 'utf-8') { | ||
427 | return $str; | ||
428 | } | ||
429 | static $iconv = null; | ||
430 | if ($iconv === null) { | ||
431 | $iconv = self::iconvAvailable(); | ||
432 | } | ||
433 | if ($iconv && !$config->get('Test.ForceNoIconv')) { | ||
434 | // Undo our previous fix in convertToUTF8, otherwise iconv will barf | ||
435 | $ascii_fix = self::testEncodingSupportsASCII($encoding); | ||
436 | if (!$escape && !empty($ascii_fix)) { | ||
437 | $clear_fix = array(); | ||
438 | foreach ($ascii_fix as $utf8 => $native) { | ||
439 | $clear_fix[$utf8] = ''; | ||
440 | } | ||
441 | $str = strtr($str, $clear_fix); | ||
442 | } | ||
443 | $str = strtr($str, array_flip($ascii_fix)); | ||
444 | // Normal stuff | ||
445 | $str = self::iconv('utf-8', $encoding . '//IGNORE', $str); | ||
446 | return $str; | ||
447 | } elseif ($encoding === 'iso-8859-1') { | ||
448 | $str = utf8_decode($str); | ||
449 | return $str; | ||
450 | } | ||
451 | trigger_error('Encoding not supported', E_USER_ERROR); | ||
452 | // You might be tempted to assume that the ASCII representation | ||
453 | // might be OK, however, this is *not* universally true over all | ||
454 | // encodings. So we take the conservative route here, rather | ||
455 | // than forcibly turn on %Core.EscapeNonASCIICharacters | ||
456 | } | ||
457 | |||
458 | /** | ||
459 | * Lossless (character-wise) conversion of HTML to ASCII | ||
460 | * @param string $str UTF-8 string to be converted to ASCII | ||
461 | * @return string ASCII encoded string with non-ASCII character entity-ized | ||
462 | * @warning Adapted from MediaWiki, claiming fair use: this is a common | ||
463 | * algorithm. If you disagree with this license fudgery, | ||
464 | * implement it yourself. | ||
465 | * @note Uses decimal numeric entities since they are best supported. | ||
466 | * @note This is a DUMB function: it has no concept of keeping | ||
467 | * character entities that the projected character encoding | ||
468 | * can allow. We could possibly implement a smart version | ||
469 | * but that would require it to also know which Unicode | ||
470 | * codepoints the charset supported (not an easy task). | ||
471 | * @note Sort of with cleanUTF8() but it assumes that $str is | ||
472 | * well-formed UTF-8 | ||
473 | */ | ||
474 | public static function convertToASCIIDumbLossless($str) | ||
475 | { | ||
476 | $bytesleft = 0; | ||
477 | $result = ''; | ||
478 | $working = 0; | ||
479 | $len = strlen($str); | ||
480 | for ($i = 0; $i < $len; $i++) { | ||
481 | $bytevalue = ord($str[$i]); | ||
482 | if ($bytevalue <= 0x7F) { //0xxx xxxx | ||
483 | $result .= chr($bytevalue); | ||
484 | $bytesleft = 0; | ||
485 | } elseif ($bytevalue <= 0xBF) { //10xx xxxx | ||
486 | $working = $working << 6; | ||
487 | $working += ($bytevalue & 0x3F); | ||
488 | $bytesleft--; | ||
489 | if ($bytesleft <= 0) { | ||
490 | $result .= "&#" . $working . ";"; | ||
491 | } | ||
492 | } elseif ($bytevalue <= 0xDF) { //110x xxxx | ||
493 | $working = $bytevalue & 0x1F; | ||
494 | $bytesleft = 1; | ||
495 | } elseif ($bytevalue <= 0xEF) { //1110 xxxx | ||
496 | $working = $bytevalue & 0x0F; | ||
497 | $bytesleft = 2; | ||
498 | } else { //1111 0xxx | ||
499 | $working = $bytevalue & 0x07; | ||
500 | $bytesleft = 3; | ||
501 | } | ||
502 | } | ||
503 | return $result; | ||
504 | } | ||
505 | |||
506 | /** No bugs detected in iconv. */ | ||
507 | const ICONV_OK = 0; | ||
508 | |||
509 | /** Iconv truncates output if converting from UTF-8 to another | ||
510 | * character set with //IGNORE, and a non-encodable character is found */ | ||
511 | const ICONV_TRUNCATES = 1; | ||
512 | |||
513 | /** Iconv does not support //IGNORE, making it unusable for | ||
514 | * transcoding purposes */ | ||
515 | const ICONV_UNUSABLE = 2; | ||
516 | |||
517 | /** | ||
518 | * glibc iconv has a known bug where it doesn't handle the magic | ||
519 | * //IGNORE stanza correctly. In particular, rather than ignore | ||
520 | * characters, it will return an EILSEQ after consuming some number | ||
521 | * of characters, and expect you to restart iconv as if it were | ||
522 | * an E2BIG. Old versions of PHP did not respect the errno, and | ||
523 | * returned the fragment, so as a result you would see iconv | ||
524 | * mysteriously truncating output. We can work around this by | ||
525 | * manually chopping our input into segments of about 8000 | ||
526 | * characters, as long as PHP ignores the error code. If PHP starts | ||
527 | * paying attention to the error code, iconv becomes unusable. | ||
528 | * | ||
529 | * @return int Error code indicating severity of bug. | ||
530 | */ | ||
531 | public static function testIconvTruncateBug() | ||
532 | { | ||
533 | static $code = null; | ||
534 | if ($code === null) { | ||
535 | // better not use iconv, otherwise infinite loop! | ||
536 | $r = self::unsafeIconv('utf-8', 'ascii//IGNORE', "\xCE\xB1" . str_repeat('a', 9000)); | ||
537 | if ($r === false) { | ||
538 | $code = self::ICONV_UNUSABLE; | ||
539 | } elseif (($c = strlen($r)) < 9000) { | ||
540 | $code = self::ICONV_TRUNCATES; | ||
541 | } elseif ($c > 9000) { | ||
542 | trigger_error( | ||
543 | 'Your copy of iconv is extremely buggy. Please notify HTML Purifier maintainers: ' . | ||
544 | 'include your iconv version as per phpversion()', | ||
545 | E_USER_ERROR | ||
546 | ); | ||
547 | } else { | ||
548 | $code = self::ICONV_OK; | ||
549 | } | ||
550 | } | ||
551 | return $code; | ||
552 | } | ||
553 | |||
554 | /** | ||
555 | * This expensive function tests whether or not a given character | ||
556 | * encoding supports ASCII. 7/8-bit encodings like Shift_JIS will | ||
557 | * fail this test, and require special processing. Variable width | ||
558 | * encodings shouldn't ever fail. | ||
559 | * | ||
560 | * @param string $encoding Encoding name to test, as per iconv format | ||
561 | * @param bool $bypass Whether or not to bypass the precompiled arrays. | ||
562 | * @return Array of UTF-8 characters to their corresponding ASCII, | ||
563 | * which can be used to "undo" any overzealous iconv action. | ||
564 | */ | ||
565 | public static function testEncodingSupportsASCII($encoding, $bypass = false) | ||
566 | { | ||
567 | // All calls to iconv here are unsafe, proof by case analysis: | ||
568 | // If ICONV_OK, no difference. | ||
569 | // If ICONV_TRUNCATE, all calls involve one character inputs, | ||
570 | // so bug is not triggered. | ||
571 | // If ICONV_UNUSABLE, this call is irrelevant | ||
572 | static $encodings = array(); | ||
573 | if (!$bypass) { | ||
574 | if (isset($encodings[$encoding])) { | ||
575 | return $encodings[$encoding]; | ||
576 | } | ||
577 | $lenc = strtolower($encoding); | ||
578 | switch ($lenc) { | ||
579 | case 'shift_jis': | ||
580 | return array("\xC2\xA5" => '\\', "\xE2\x80\xBE" => '~'); | ||
581 | case 'johab': | ||
582 | return array("\xE2\x82\xA9" => '\\'); | ||
583 | } | ||
584 | if (strpos($lenc, 'iso-8859-') === 0) { | ||
585 | return array(); | ||
586 | } | ||
587 | } | ||
588 | $ret = array(); | ||
589 | if (self::unsafeIconv('UTF-8', $encoding, 'a') === false) { | ||
590 | return false; | ||
591 | } | ||
592 | for ($i = 0x20; $i <= 0x7E; $i++) { // all printable ASCII chars | ||
593 | $c = chr($i); // UTF-8 char | ||
594 | $r = self::unsafeIconv('UTF-8', "$encoding//IGNORE", $c); // initial conversion | ||
595 | if ($r === '' || | ||
596 | // This line is needed for iconv implementations that do not | ||
597 | // omit characters that do not exist in the target character set | ||
598 | ($r === $c && self::unsafeIconv($encoding, 'UTF-8//IGNORE', $r) !== $c) | ||
599 | ) { | ||
600 | // Reverse engineer: what's the UTF-8 equiv of this byte | ||
601 | // sequence? This assumes that there's no variable width | ||
602 | // encoding that doesn't support ASCII. | ||
603 | $ret[self::unsafeIconv($encoding, 'UTF-8//IGNORE', $c)] = $c; | ||
604 | } | ||
605 | } | ||
606 | $encodings[$encoding] = $ret; | ||
607 | return $ret; | ||
608 | } | ||
609 | } | ||
610 | |||
611 | // vim: et sw=4 sts=4 | ||