--- /dev/null
+<?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.
+ *
+ * Specifically, it will permit:
+ * \x{9}\x{A}\x{D}\x{20}-\x{7E}\x{A0}-\x{D7FF}\x{E000}-\x{FFFD}\x{10000}-\x{10FFFF}
+ * Source: https://www.w3.org/TR/REC-xml/#NT-Char
+ * Arguably this function should be modernized to the HTML5 set
+ * of allowed characters:
+ * https://www.w3.org/TR/html5/syntax.html#preprocessing-the-input-stream
+ * which simultaneously expand and restrict the set of allowed characters.
+ *
+ * @param string $str The string to clean
+ * @param bool $force_php
+ * @return string
+ *
+ * @note Just for reference, the non-SGML code points are 0 to 31 and
+ * 127 to 159, inclusive. However, we allow code points 9, 10
+ * and 13, which are the tab, line feed and carriage return
+ * respectively. 128 and above the code points map to multibyte
+ * UTF-8 representations.
+ *
+ * @note Fallback code adapted from utf8ToUnicode by Henri Sivonen and
+ * hsivonen@iki.fi at <http://iki.fi/hsivonen/php-utf8/> under the
+ * LGPL license. Notes on what changed are inside, but in general,
+ * the original code transformed UTF-8 text into an array of integer
+ * Unicode codepoints. Understandably, transforming that back to
+ * a string would be somewhat expensive, so the function was modded to
+ * directly operate on the string. However, this discourages code
+ * reuse, and the logic enumerated here would be useful for any
+ * function that needs to be able to understand UTF-8 characters.
+ * As of right now, only smart lossless character encoding converters
+ * would need that, and I'm probably not going to implement them.
+ */
+ public static function cleanUTF8($str, $force_php = false)
+ {
+ // UTF-8 validity is checked since PHP 4.3.5
+ // This is an optimization: if the string is already valid UTF-8, no
+ // need to do PHP stuff. 99% of the time, this will be the case.
+ if (preg_match(
+ '/^[\x{9}\x{A}\x{D}\x{20}-\x{7E}\x{A0}-\x{D7FF}\x{E000}-\x{FFFD}\x{10000}-\x{10FFFF}]*$/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) ||
+ (0xE000 <= $mUcs4 && 0xFFFD >= $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
projects / yaffs-website / blobdiff