= $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 $force_php * @return string * * @note Just for reference, the non-SGML code points are 0 to 31 and * 127 to 159, inclusive. However, we allow code points 9, 10 * and 13, which are the tab, line feed and carriage return * respectively. 128 and above the code points map to multibyte * UTF-8 representations. * * @note Fallback code adapted from utf8ToUnicode by Henri Sivonen and * hsivonen@iki.fi at under the * LGPL license. Notes on what changed are inside, but in general, * the original code transformed UTF-8 text into an array of integer * Unicode codepoints. Understandably, transforming that back to * a string would be somewhat expensive, so the function was modded to * directly operate on the string. However, this discourages code * reuse, and the logic enumerated here would be useful for any * function that needs to be able to understand UTF-8 characters. * As of right now, only smart lossless character encoding converters * would need that, and I'm probably not going to implement them. * Once again, PHP 6 should solve all our problems. */ public static function cleanUTF8($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 $out; } /** * Translates a Unicode codepoint into its corresponding UTF-8 character. * @note Based on Feyd's function at * , * which is in public domain. * @note While we're going to do code point parsing anyway, a good * optimization would be to refuse to translate code points that * are non-SGML characters. However, this could lead to duplication. * @note This is very similar to the unichr function in * maintenance/generate-entity-file.php (although this is superior, * due to its sanity checks). */ // +----------+----------+----------+----------+ // | 33222222 | 22221111 | 111111 | | // | 10987654 | 32109876 | 54321098 | 76543210 | bit // +----------+----------+----------+----------+ // | | | | 0xxxxxxx | 1 byte 0x00000000..0x0000007F // | | | 110yyyyy | 10xxxxxx | 2 byte 0x00000080..0x000007FF // | | 1110zzzz | 10yyyyyy | 10xxxxxx | 3 byte 0x00000800..0x0000FFFF // | 11110www | 10wwzzzz | 10yyyyyy | 10xxxxxx | 4 byte 0x00010000..0x0010FFFF // +----------+----------+----------+----------+ // | 00000000 | 00011111 | 11111111 | 11111111 | Theoretical upper limit of legal scalars: 2097151 (0x001FFFFF) // | 00000000 | 00010000 | 11111111 | 11111111 | Defined upper limit of legal scalar codes // +----------+----------+----------+----------+ public static function unichr($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