diff options
Diffstat (limited to 'library/HTMLPurifier/Encoder.php')
| -rw-r--r-- | library/HTMLPurifier/Encoder.php | 611 |
1 files changed, 0 insertions, 611 deletions
diff --git a/library/HTMLPurifier/Encoder.php b/library/HTMLPurifier/Encoder.php deleted file mode 100644 index fef9b5890..000000000 --- a/library/HTMLPurifier/Encoder.php +++ /dev/null @@ -1,611 +0,0 @@ -<?php - -/** - * A UTF-8 specific character encoder that handles cleaning and transforming. - * @note All functions in this class should be static. - */ -class HTMLPurifier_Encoder -{ - - /** - * Constructor throws fatal error if you attempt to instantiate class - */ - private function __construct() - { - trigger_error('Cannot instantiate encoder, call methods statically', E_USER_ERROR); - } - - /** - * Error-handler that mutes errors, alternative to shut-up operator. - */ - public static function muteErrorHandler() - { - } - - /** - * iconv wrapper which mutes errors, but doesn't work around bugs. - * @param string $in Input encoding - * @param string $out Output encoding - * @param string $text The text to convert - * @return string - */ - public static function unsafeIconv($in, $out, $text) - { - set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler')); - $r = iconv($in, $out, $text); - restore_error_handler(); - return $r; - } - - /** - * iconv wrapper which mutes errors and works around bugs. - * @param string $in Input encoding - * @param string $out Output encoding - * @param string $text The text to convert - * @param int $max_chunk_size - * @return string - */ - public static function iconv($in, $out, $text, $max_chunk_size = 8000) - { - $code = self::testIconvTruncateBug(); - if ($code == self::ICONV_OK) { - return self::unsafeIconv($in, $out, $text); - } elseif ($code == self::ICONV_TRUNCATES) { - // we can only work around this if the input character set - // is utf-8 - if ($in == 'utf-8') { - if ($max_chunk_size < 4) { - trigger_error('max_chunk_size is too small', E_USER_WARNING); - return false; - } - // split into 8000 byte chunks, but be careful to handle - // multibyte boundaries properly - if (($c = strlen($text)) <= $max_chunk_size) { - return self::unsafeIconv($in, $out, $text); - } - $r = ''; - $i = 0; - while (true) { - if ($i + $max_chunk_size >= $c) { - $r .= self::unsafeIconv($in, $out, substr($text, $i)); - break; - } - // wibble the boundary - if (0x80 != (0xC0 & ord($text[$i + $max_chunk_size]))) { - $chunk_size = $max_chunk_size; - } elseif (0x80 != (0xC0 & ord($text[$i + $max_chunk_size - 1]))) { - $chunk_size = $max_chunk_size - 1; - } elseif (0x80 != (0xC0 & ord($text[$i + $max_chunk_size - 2]))) { - $chunk_size = $max_chunk_size - 2; - } elseif (0x80 != (0xC0 & ord($text[$i + $max_chunk_size - 3]))) { - $chunk_size = $max_chunk_size - 3; - } else { - return false; // rather confusing UTF-8... - } - $chunk = substr($text, $i, $chunk_size); // substr doesn't mind overlong lengths - $r .= self::unsafeIconv($in, $out, $chunk); - $i += $chunk_size; - } - return $r; - } else { - return false; - } - } else { - return false; - } - } - - /** - * Cleans a UTF-8 string for well-formedness and SGML validity - * - * It will parse according to UTF-8 and return a valid UTF8 string, with - * non-SGML codepoints excluded. - * - * @param string $str The string to clean - * @param bool $force_php - * @return string - * - * @note Just for reference, the non-SGML code points are 0 to 31 and - * 127 to 159, inclusive. However, we allow code points 9, 10 - * and 13, which are the tab, line feed and carriage return - * respectively. 128 and above the code points map to multibyte - * UTF-8 representations. - * - * @note Fallback code adapted from utf8ToUnicode by Henri Sivonen and - * hsivonen@iki.fi at <http://iki.fi/hsivonen/php-utf8/> under the - * LGPL license. Notes on what changed are inside, but in general, - * the original code transformed UTF-8 text into an array of integer - * Unicode codepoints. Understandably, transforming that back to - * a string would be somewhat expensive, so the function was modded to - * directly operate on the string. However, this discourages code - * reuse, and the logic enumerated here would be useful for any - * function that needs to be able to understand UTF-8 characters. - * As of right now, only smart lossless character encoding converters - * would need that, and I'm probably not going to implement them. - * Once again, PHP 6 should solve all our problems. - */ - public static function cleanUTF8($str, $force_php = false) - { - // UTF-8 validity is checked since PHP 4.3.5 - // This is an optimization: if the string is already valid UTF-8, no - // need to do PHP stuff. 99% of the time, this will be the case. - // The regexp matches the XML char production, as well as well as excluding - // non-SGML codepoints U+007F to U+009F - if (preg_match( - '/^[\x{9}\x{A}\x{D}\x{20}-\x{7E}\x{A0}-\x{D7FF}\x{E000}-\x{FFFD}\x{10000}-\x{10FFFF}]*$/Du', - $str - )) { - return $str; - } - - $mState = 0; // cached expected number of octets after the current octet - // until the beginning of the next UTF8 character sequence - $mUcs4 = 0; // cached Unicode character - $mBytes = 1; // cached expected number of octets in the current sequence - - // original code involved an $out that was an array of Unicode - // codepoints. Instead of having to convert back into UTF-8, we've - // decided to directly append valid UTF-8 characters onto a string - // $out once they're done. $char accumulates raw bytes, while $mUcs4 - // turns into the Unicode code point, so there's some redundancy. - - $out = ''; - $char = ''; - - $len = strlen($str); - for ($i = 0; $i < $len; $i++) { - $in = ord($str{$i}); - $char .= $str[$i]; // append byte to char - if (0 == $mState) { - // When mState is zero we expect either a US-ASCII character - // or a multi-octet sequence. - if (0 == (0x80 & ($in))) { - // US-ASCII, pass straight through. - if (($in <= 31 || $in == 127) && - !($in == 9 || $in == 13 || $in == 10) // save \r\t\n - ) { - // control characters, remove - } else { - $out .= $char; - } - // reset - $char = ''; - $mBytes = 1; - } elseif (0xC0 == (0xE0 & ($in))) { - // First octet of 2 octet sequence - $mUcs4 = ($in); - $mUcs4 = ($mUcs4 & 0x1F) << 6; - $mState = 1; - $mBytes = 2; - } elseif (0xE0 == (0xF0 & ($in))) { - // First octet of 3 octet sequence - $mUcs4 = ($in); - $mUcs4 = ($mUcs4 & 0x0F) << 12; - $mState = 2; - $mBytes = 3; - } elseif (0xF0 == (0xF8 & ($in))) { - // First octet of 4 octet sequence - $mUcs4 = ($in); - $mUcs4 = ($mUcs4 & 0x07) << 18; - $mState = 3; - $mBytes = 4; - } elseif (0xF8 == (0xFC & ($in))) { - // First octet of 5 octet sequence. - // - // This is illegal because the encoded codepoint must be - // either: - // (a) not the shortest form or - // (b) outside the Unicode range of 0-0x10FFFF. - // Rather than trying to resynchronize, we will carry on - // until the end of the sequence and let the later error - // handling code catch it. - $mUcs4 = ($in); - $mUcs4 = ($mUcs4 & 0x03) << 24; - $mState = 4; - $mBytes = 5; - } elseif (0xFC == (0xFE & ($in))) { - // First octet of 6 octet sequence, see comments for 5 - // octet sequence. - $mUcs4 = ($in); - $mUcs4 = ($mUcs4 & 1) << 30; - $mState = 5; - $mBytes = 6; - } else { - // Current octet is neither in the US-ASCII range nor a - // legal first octet of a multi-octet sequence. - $mState = 0; - $mUcs4 = 0; - $mBytes = 1; - $char = ''; - } - } else { - // When mState is non-zero, we expect a continuation of the - // multi-octet sequence - if (0x80 == (0xC0 & ($in))) { - // Legal continuation. - $shift = ($mState - 1) * 6; - $tmp = $in; - $tmp = ($tmp & 0x0000003F) << $shift; - $mUcs4 |= $tmp; - - if (0 == --$mState) { - // End of the multi-octet sequence. mUcs4 now contains - // the final Unicode codepoint to be output - - // Check for illegal sequences and codepoints. - - // From Unicode 3.1, non-shortest form is illegal - if (((2 == $mBytes) && ($mUcs4 < 0x0080)) || - ((3 == $mBytes) && ($mUcs4 < 0x0800)) || - ((4 == $mBytes) && ($mUcs4 < 0x10000)) || - (4 < $mBytes) || - // From Unicode 3.2, surrogate characters = illegal - (($mUcs4 & 0xFFFFF800) == 0xD800) || - // Codepoints outside the Unicode range are illegal - ($mUcs4 > 0x10FFFF) - ) { - - } elseif (0xFEFF != $mUcs4 && // omit BOM - // check for valid Char unicode codepoints - ( - 0x9 == $mUcs4 || - 0xA == $mUcs4 || - 0xD == $mUcs4 || - (0x20 <= $mUcs4 && 0x7E >= $mUcs4) || - // 7F-9F is not strictly prohibited by XML, - // but it is non-SGML, and thus we don't allow it - (0xA0 <= $mUcs4 && 0xD7FF >= $mUcs4) || - (0x10000 <= $mUcs4 && 0x10FFFF >= $mUcs4) - ) - ) { - $out .= $char; - } - // initialize UTF8 cache (reset) - $mState = 0; - $mUcs4 = 0; - $mBytes = 1; - $char = ''; - } - } else { - // ((0xC0 & (*in) != 0x80) && (mState != 0)) - // Incomplete multi-octet sequence. - // used to result in complete fail, but we'll reset - $mState = 0; - $mUcs4 = 0; - $mBytes = 1; - $char =''; - } - } - } - return $out; - } - - /** - * Translates a Unicode codepoint into its corresponding UTF-8 character. - * @note Based on Feyd's function at - * <http://forums.devnetwork.net/viewtopic.php?p=191404#191404>, - * which is in public domain. - * @note While we're going to do code point parsing anyway, a good - * optimization would be to refuse to translate code points that - * are non-SGML characters. However, this could lead to duplication. - * @note This is very similar to the unichr function in - * maintenance/generate-entity-file.php (although this is superior, - * due to its sanity checks). - */ - - // +----------+----------+----------+----------+ - // | 33222222 | 22221111 | 111111 | | - // | 10987654 | 32109876 | 54321098 | 76543210 | bit - // +----------+----------+----------+----------+ - // | | | | 0xxxxxxx | 1 byte 0x00000000..0x0000007F - // | | | 110yyyyy | 10xxxxxx | 2 byte 0x00000080..0x000007FF - // | | 1110zzzz | 10yyyyyy | 10xxxxxx | 3 byte 0x00000800..0x0000FFFF - // | 11110www | 10wwzzzz | 10yyyyyy | 10xxxxxx | 4 byte 0x00010000..0x0010FFFF - // +----------+----------+----------+----------+ - // | 00000000 | 00011111 | 11111111 | 11111111 | Theoretical upper limit of legal scalars: 2097151 (0x001FFFFF) - // | 00000000 | 00010000 | 11111111 | 11111111 | Defined upper limit of legal scalar codes - // +----------+----------+----------+----------+ - - public static function unichr($code) - { - if ($code > 1114111 or $code < 0 or - ($code >= 55296 and $code <= 57343) ) { - // bits are set outside the "valid" range as defined - // by UNICODE 4.1.0 - return ''; - } - - $x = $y = $z = $w = 0; - if ($code < 128) { - // regular ASCII character - $x = $code; - } else { - // set up bits for UTF-8 - $x = ($code & 63) | 128; - if ($code < 2048) { - $y = (($code & 2047) >> 6) | 192; - } else { - $y = (($code & 4032) >> 6) | 128; - if ($code < 65536) { - $z = (($code >> 12) & 15) | 224; - } else { - $z = (($code >> 12) & 63) | 128; - $w = (($code >> 18) & 7) | 240; - } - } - } - // set up the actual character - $ret = ''; - if ($w) { - $ret .= chr($w); - } - if ($z) { - $ret .= chr($z); - } - if ($y) { - $ret .= chr($y); - } - $ret .= chr($x); - - return $ret; - } - - /** - * @return bool - */ - public static function iconvAvailable() - { - static $iconv = null; - if ($iconv === null) { - $iconv = function_exists('iconv') && self::testIconvTruncateBug() != self::ICONV_UNUSABLE; - } - return $iconv; - } - - /** - * Convert a string to UTF-8 based on configuration. - * @param string $str The string to convert - * @param HTMLPurifier_Config $config - * @param HTMLPurifier_Context $context - * @return string - */ - public static function convertToUTF8($str, $config, $context) - { - $encoding = $config->get('Core.Encoding'); - if ($encoding === 'utf-8') { - return $str; - } - static $iconv = null; - if ($iconv === null) { - $iconv = self::iconvAvailable(); - } - if ($iconv && !$config->get('Test.ForceNoIconv')) { - // unaffected by bugs, since UTF-8 support all characters - $str = self::unsafeIconv($encoding, 'utf-8//IGNORE', $str); - if ($str === false) { - // $encoding is not a valid encoding - trigger_error('Invalid encoding ' . $encoding, E_USER_ERROR); - return ''; - } - // If the string is bjorked by Shift_JIS or a similar encoding - // that doesn't support all of ASCII, convert the naughty - // characters to their true byte-wise ASCII/UTF-8 equivalents. - $str = strtr($str, self::testEncodingSupportsASCII($encoding)); - return $str; - } elseif ($encoding === 'iso-8859-1') { - $str = utf8_encode($str); - return $str; - } - $bug = HTMLPurifier_Encoder::testIconvTruncateBug(); - if ($bug == self::ICONV_OK) { - trigger_error('Encoding not supported, please install iconv', E_USER_ERROR); - } else { - trigger_error( - 'You have a buggy version of iconv, see https://bugs.php.net/bug.php?id=48147 ' . - 'and http://sourceware.org/bugzilla/show_bug.cgi?id=13541', - E_USER_ERROR - ); - } - } - - /** - * Converts a string from UTF-8 based on configuration. - * @param string $str The string to convert - * @param HTMLPurifier_Config $config - * @param HTMLPurifier_Context $context - * @return string - * @note Currently, this is a lossy conversion, with unexpressable - * characters being omitted. - */ - public static function convertFromUTF8($str, $config, $context) - { - $encoding = $config->get('Core.Encoding'); - if ($escape = $config->get('Core.EscapeNonASCIICharacters')) { - $str = self::convertToASCIIDumbLossless($str); - } - if ($encoding === 'utf-8') { - return $str; - } - static $iconv = null; - if ($iconv === null) { - $iconv = self::iconvAvailable(); - } - if ($iconv && !$config->get('Test.ForceNoIconv')) { - // Undo our previous fix in convertToUTF8, otherwise iconv will barf - $ascii_fix = self::testEncodingSupportsASCII($encoding); - if (!$escape && !empty($ascii_fix)) { - $clear_fix = array(); - foreach ($ascii_fix as $utf8 => $native) { - $clear_fix[$utf8] = ''; - } - $str = strtr($str, $clear_fix); - } - $str = strtr($str, array_flip($ascii_fix)); - // Normal stuff - $str = self::iconv('utf-8', $encoding . '//IGNORE', $str); - return $str; - } elseif ($encoding === 'iso-8859-1') { - $str = utf8_decode($str); - return $str; - } - trigger_error('Encoding not supported', E_USER_ERROR); - // You might be tempted to assume that the ASCII representation - // might be OK, however, this is *not* universally true over all - // encodings. So we take the conservative route here, rather - // than forcibly turn on %Core.EscapeNonASCIICharacters - } - - /** - * Lossless (character-wise) conversion of HTML to ASCII - * @param string $str UTF-8 string to be converted to ASCII - * @return string ASCII encoded string with non-ASCII character entity-ized - * @warning Adapted from MediaWiki, claiming fair use: this is a common - * algorithm. If you disagree with this license fudgery, - * implement it yourself. - * @note Uses decimal numeric entities since they are best supported. - * @note This is a DUMB function: it has no concept of keeping - * character entities that the projected character encoding - * can allow. We could possibly implement a smart version - * but that would require it to also know which Unicode - * codepoints the charset supported (not an easy task). - * @note Sort of with cleanUTF8() but it assumes that $str is - * well-formed UTF-8 - */ - public static function convertToASCIIDumbLossless($str) - { - $bytesleft = 0; - $result = ''; - $working = 0; - $len = strlen($str); - for ($i = 0; $i < $len; $i++) { - $bytevalue = ord($str[$i]); - if ($bytevalue <= 0x7F) { //0xxx xxxx - $result .= chr($bytevalue); - $bytesleft = 0; - } elseif ($bytevalue <= 0xBF) { //10xx xxxx - $working = $working << 6; - $working += ($bytevalue & 0x3F); - $bytesleft--; - if ($bytesleft <= 0) { - $result .= "&#" . $working . ";"; - } - } elseif ($bytevalue <= 0xDF) { //110x xxxx - $working = $bytevalue & 0x1F; - $bytesleft = 1; - } elseif ($bytevalue <= 0xEF) { //1110 xxxx - $working = $bytevalue & 0x0F; - $bytesleft = 2; - } else { //1111 0xxx - $working = $bytevalue & 0x07; - $bytesleft = 3; - } - } - return $result; - } - - /** No bugs detected in iconv. */ - const ICONV_OK = 0; - - /** Iconv truncates output if converting from UTF-8 to another - * character set with //IGNORE, and a non-encodable character is found */ - const ICONV_TRUNCATES = 1; - - /** Iconv does not support //IGNORE, making it unusable for - * transcoding purposes */ - const ICONV_UNUSABLE = 2; - - /** - * glibc iconv has a known bug where it doesn't handle the magic - * //IGNORE stanza correctly. In particular, rather than ignore - * characters, it will return an EILSEQ after consuming some number - * of characters, and expect you to restart iconv as if it were - * an E2BIG. Old versions of PHP did not respect the errno, and - * returned the fragment, so as a result you would see iconv - * mysteriously truncating output. We can work around this by - * manually chopping our input into segments of about 8000 - * characters, as long as PHP ignores the error code. If PHP starts - * paying attention to the error code, iconv becomes unusable. - * - * @return int Error code indicating severity of bug. - */ - public static function testIconvTruncateBug() - { - static $code = null; - if ($code === null) { - // better not use iconv, otherwise infinite loop! - $r = self::unsafeIconv('utf-8', 'ascii//IGNORE', "\xCE\xB1" . str_repeat('a', 9000)); - if ($r === false) { - $code = self::ICONV_UNUSABLE; - } elseif (($c = strlen($r)) < 9000) { - $code = self::ICONV_TRUNCATES; - } elseif ($c > 9000) { - trigger_error( - 'Your copy of iconv is extremely buggy. Please notify HTML Purifier maintainers: ' . - 'include your iconv version as per phpversion()', - E_USER_ERROR - ); - } else { - $code = self::ICONV_OK; - } - } - return $code; - } - - /** - * This expensive function tests whether or not a given character - * encoding supports ASCII. 7/8-bit encodings like Shift_JIS will - * fail this test, and require special processing. Variable width - * encodings shouldn't ever fail. - * - * @param string $encoding Encoding name to test, as per iconv format - * @param bool $bypass Whether or not to bypass the precompiled arrays. - * @return Array of UTF-8 characters to their corresponding ASCII, - * which can be used to "undo" any overzealous iconv action. - */ - public static function testEncodingSupportsASCII($encoding, $bypass = false) - { - // All calls to iconv here are unsafe, proof by case analysis: - // If ICONV_OK, no difference. - // If ICONV_TRUNCATE, all calls involve one character inputs, - // so bug is not triggered. - // If ICONV_UNUSABLE, this call is irrelevant - static $encodings = array(); - if (!$bypass) { - if (isset($encodings[$encoding])) { - return $encodings[$encoding]; - } - $lenc = strtolower($encoding); - switch ($lenc) { - case 'shift_jis': - return array("\xC2\xA5" => '\\', "\xE2\x80\xBE" => '~'); - case 'johab': - return array("\xE2\x82\xA9" => '\\'); - } - if (strpos($lenc, 'iso-8859-') === 0) { - return array(); - } - } - $ret = array(); - if (self::unsafeIconv('UTF-8', $encoding, 'a') === false) { - return false; - } - for ($i = 0x20; $i <= 0x7E; $i++) { // all printable ASCII chars - $c = chr($i); // UTF-8 char - $r = self::unsafeIconv('UTF-8', "$encoding//IGNORE", $c); // initial conversion - if ($r === '' || - // This line is needed for iconv implementations that do not - // omit characters that do not exist in the target character set - ($r === $c && self::unsafeIconv($encoding, 'UTF-8//IGNORE', $r) !== $c) - ) { - // Reverse engineer: what's the UTF-8 equiv of this byte - // sequence? This assumes that there's no variable width - // encoding that doesn't support ASCII. - $ret[self::unsafeIconv($encoding, 'UTF-8//IGNORE', $c)] = $c; - } - } - $encodings[$encoding] = $ret; - return $ret; - } -} - -// vim: et sw=4 sts=4 |