mirror of
https://github.com/ezyang/htmlpurifier.git
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7e11c271b9
See %Core.LegacyEntityDecoder for more details. Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
540 lines
20 KiB
PHP
540 lines
20 KiB
PHP
<?php
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/**
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* Our in-house implementation of a parser.
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*
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* A pure PHP parser, DirectLex has absolutely no dependencies, making
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* it a reasonably good default for PHP4. Written with efficiency in mind,
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* it can be four times faster than HTMLPurifier_Lexer_PEARSax3, although it
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* pales in comparison to HTMLPurifier_Lexer_DOMLex.
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*
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* @todo Reread XML spec and document differences.
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*/
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class HTMLPurifier_Lexer_DirectLex extends HTMLPurifier_Lexer
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{
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/**
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* @type bool
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*/
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public $tracksLineNumbers = true;
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/**
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* Whitespace characters for str(c)spn.
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* @type string
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*/
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protected $_whitespace = "\x20\x09\x0D\x0A";
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/**
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* Callback function for script CDATA fudge
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* @param array $matches, in form of array(opening tag, contents, closing tag)
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* @return string
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*/
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protected function scriptCallback($matches)
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{
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return $matches[1] . htmlspecialchars($matches[2], ENT_COMPAT, 'UTF-8') . $matches[3];
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}
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/**
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* @param String $html
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* @param HTMLPurifier_Config $config
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* @param HTMLPurifier_Context $context
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* @return array|HTMLPurifier_Token[]
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*/
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public function tokenizeHTML($html, $config, $context)
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{
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// special normalization for script tags without any armor
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// our "armor" heurstic is a < sign any number of whitespaces after
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// the first script tag
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if ($config->get('HTML.Trusted')) {
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$html = preg_replace_callback(
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'#(<script[^>]*>)(\s*[^<].+?)(</script>)#si',
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array($this, 'scriptCallback'),
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$html
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);
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}
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$html = $this->normalize($html, $config, $context);
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$cursor = 0; // our location in the text
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$inside_tag = false; // whether or not we're parsing the inside of a tag
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$array = array(); // result array
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// This is also treated to mean maintain *column* numbers too
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$maintain_line_numbers = $config->get('Core.MaintainLineNumbers');
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if ($maintain_line_numbers === null) {
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// automatically determine line numbering by checking
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// if error collection is on
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$maintain_line_numbers = $config->get('Core.CollectErrors');
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}
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if ($maintain_line_numbers) {
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$current_line = 1;
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$current_col = 0;
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$length = strlen($html);
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} else {
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$current_line = false;
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$current_col = false;
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$length = false;
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}
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$context->register('CurrentLine', $current_line);
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$context->register('CurrentCol', $current_col);
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$nl = "\n";
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// how often to manually recalculate. This will ALWAYS be right,
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// but it's pretty wasteful. Set to 0 to turn off
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$synchronize_interval = $config->get('Core.DirectLexLineNumberSyncInterval');
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$e = false;
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if ($config->get('Core.CollectErrors')) {
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$e =& $context->get('ErrorCollector');
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}
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// for testing synchronization
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$loops = 0;
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while (++$loops) {
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// $cursor is either at the start of a token, or inside of
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// a tag (i.e. there was a < immediately before it), as indicated
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// by $inside_tag
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if ($maintain_line_numbers) {
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// $rcursor, however, is always at the start of a token.
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$rcursor = $cursor - (int)$inside_tag;
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// Column number is cheap, so we calculate it every round.
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// We're interested at the *end* of the newline string, so
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// we need to add strlen($nl) == 1 to $nl_pos before subtracting it
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// from our "rcursor" position.
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$nl_pos = strrpos($html, $nl, $rcursor - $length);
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$current_col = $rcursor - (is_bool($nl_pos) ? 0 : $nl_pos + 1);
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// recalculate lines
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if ($synchronize_interval && // synchronization is on
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$cursor > 0 && // cursor is further than zero
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$loops % $synchronize_interval === 0) { // time to synchronize!
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$current_line = 1 + $this->substrCount($html, $nl, 0, $cursor);
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}
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}
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$position_next_lt = strpos($html, '<', $cursor);
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$position_next_gt = strpos($html, '>', $cursor);
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// triggers on "<b>asdf</b>" but not "asdf <b></b>"
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// special case to set up context
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if ($position_next_lt === $cursor) {
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$inside_tag = true;
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$cursor++;
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}
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if (!$inside_tag && $position_next_lt !== false) {
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// We are not inside tag and there still is another tag to parse
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$token = new
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HTMLPurifier_Token_Text(
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$this->parseText(
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substr(
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$html,
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$cursor,
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$position_next_lt - $cursor
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), $config
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)
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);
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if ($maintain_line_numbers) {
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$token->rawPosition($current_line, $current_col);
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$current_line += $this->substrCount($html, $nl, $cursor, $position_next_lt - $cursor);
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}
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$array[] = $token;
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$cursor = $position_next_lt + 1;
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$inside_tag = true;
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continue;
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} elseif (!$inside_tag) {
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// We are not inside tag but there are no more tags
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// If we're already at the end, break
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if ($cursor === strlen($html)) {
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break;
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}
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// Create Text of rest of string
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$token = new
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HTMLPurifier_Token_Text(
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$this->parseText(
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substr(
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$html,
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$cursor
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), $config
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)
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);
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if ($maintain_line_numbers) {
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$token->rawPosition($current_line, $current_col);
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}
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$array[] = $token;
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break;
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} elseif ($inside_tag && $position_next_gt !== false) {
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// We are in tag and it is well formed
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// Grab the internals of the tag
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$strlen_segment = $position_next_gt - $cursor;
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if ($strlen_segment < 1) {
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// there's nothing to process!
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$token = new HTMLPurifier_Token_Text('<');
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$cursor++;
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continue;
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}
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$segment = substr($html, $cursor, $strlen_segment);
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if ($segment === false) {
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// somehow, we attempted to access beyond the end of
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// the string, defense-in-depth, reported by Nate Abele
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break;
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}
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// Check if it's a comment
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if (substr($segment, 0, 3) === '!--') {
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// re-determine segment length, looking for -->
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$position_comment_end = strpos($html, '-->', $cursor);
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if ($position_comment_end === false) {
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// uh oh, we have a comment that extends to
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// infinity. Can't be helped: set comment
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// end position to end of string
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if ($e) {
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$e->send(E_WARNING, 'Lexer: Unclosed comment');
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}
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$position_comment_end = strlen($html);
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$end = true;
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} else {
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$end = false;
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}
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$strlen_segment = $position_comment_end - $cursor;
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$segment = substr($html, $cursor, $strlen_segment);
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$token = new
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HTMLPurifier_Token_Comment(
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substr(
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$segment,
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3,
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$strlen_segment - 3
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)
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);
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if ($maintain_line_numbers) {
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$token->rawPosition($current_line, $current_col);
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$current_line += $this->substrCount($html, $nl, $cursor, $strlen_segment);
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}
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$array[] = $token;
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$cursor = $end ? $position_comment_end : $position_comment_end + 3;
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$inside_tag = false;
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continue;
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}
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// Check if it's an end tag
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$is_end_tag = (strpos($segment, '/') === 0);
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if ($is_end_tag) {
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$type = substr($segment, 1);
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$token = new HTMLPurifier_Token_End($type);
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if ($maintain_line_numbers) {
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$token->rawPosition($current_line, $current_col);
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$current_line += $this->substrCount($html, $nl, $cursor, $position_next_gt - $cursor);
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}
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$array[] = $token;
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$inside_tag = false;
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$cursor = $position_next_gt + 1;
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continue;
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}
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// Check leading character is alnum, if not, we may
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// have accidently grabbed an emoticon. Translate into
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// text and go our merry way
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if (!ctype_alpha($segment[0])) {
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// XML: $segment[0] !== '_' && $segment[0] !== ':'
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if ($e) {
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$e->send(E_NOTICE, 'Lexer: Unescaped lt');
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}
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$token = new HTMLPurifier_Token_Text('<');
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if ($maintain_line_numbers) {
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$token->rawPosition($current_line, $current_col);
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$current_line += $this->substrCount($html, $nl, $cursor, $position_next_gt - $cursor);
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}
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$array[] = $token;
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$inside_tag = false;
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continue;
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}
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// Check if it is explicitly self closing, if so, remove
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// trailing slash. Remember, we could have a tag like <br>, so
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// any later token processing scripts must convert improperly
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// classified EmptyTags from StartTags.
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$is_self_closing = (strrpos($segment, '/') === $strlen_segment - 1);
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if ($is_self_closing) {
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$strlen_segment--;
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$segment = substr($segment, 0, $strlen_segment);
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}
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// Check if there are any attributes
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$position_first_space = strcspn($segment, $this->_whitespace);
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if ($position_first_space >= $strlen_segment) {
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if ($is_self_closing) {
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$token = new HTMLPurifier_Token_Empty($segment);
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} else {
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$token = new HTMLPurifier_Token_Start($segment);
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}
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if ($maintain_line_numbers) {
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$token->rawPosition($current_line, $current_col);
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$current_line += $this->substrCount($html, $nl, $cursor, $position_next_gt - $cursor);
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}
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$array[] = $token;
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$inside_tag = false;
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$cursor = $position_next_gt + 1;
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continue;
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}
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// Grab out all the data
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$type = substr($segment, 0, $position_first_space);
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$attribute_string =
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trim(
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substr(
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$segment,
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$position_first_space
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)
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);
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if ($attribute_string) {
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$attr = $this->parseAttributeString(
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$attribute_string,
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$config,
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$context
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);
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} else {
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$attr = array();
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}
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if ($is_self_closing) {
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$token = new HTMLPurifier_Token_Empty($type, $attr);
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} else {
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$token = new HTMLPurifier_Token_Start($type, $attr);
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}
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if ($maintain_line_numbers) {
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$token->rawPosition($current_line, $current_col);
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$current_line += $this->substrCount($html, $nl, $cursor, $position_next_gt - $cursor);
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}
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$array[] = $token;
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$cursor = $position_next_gt + 1;
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$inside_tag = false;
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continue;
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} else {
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// inside tag, but there's no ending > sign
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if ($e) {
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$e->send(E_WARNING, 'Lexer: Missing gt');
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}
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$token = new
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HTMLPurifier_Token_Text(
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'<' .
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$this->parseText(
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substr($html, $cursor), $config
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)
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);
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if ($maintain_line_numbers) {
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$token->rawPosition($current_line, $current_col);
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}
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// no cursor scroll? Hmm...
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$array[] = $token;
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break;
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}
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break;
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}
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$context->destroy('CurrentLine');
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$context->destroy('CurrentCol');
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return $array;
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}
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/**
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* PHP 5.0.x compatible substr_count that implements offset and length
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* @param string $haystack
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* @param string $needle
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* @param int $offset
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* @param int $length
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* @return int
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*/
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protected function substrCount($haystack, $needle, $offset, $length)
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{
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static $oldVersion;
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if ($oldVersion === null) {
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$oldVersion = version_compare(PHP_VERSION, '5.1', '<');
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}
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if ($oldVersion) {
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$haystack = substr($haystack, $offset, $length);
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return substr_count($haystack, $needle);
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} else {
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return substr_count($haystack, $needle, $offset, $length);
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}
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}
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/**
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* Takes the inside of an HTML tag and makes an assoc array of attributes.
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*
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* @param string $string Inside of tag excluding name.
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* @param HTMLPurifier_Config $config
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* @param HTMLPurifier_Context $context
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* @return array Assoc array of attributes.
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*/
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public function parseAttributeString($string, $config, $context)
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{
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$string = (string)$string; // quick typecast
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if ($string == '') {
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return array();
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} // no attributes
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$e = false;
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if ($config->get('Core.CollectErrors')) {
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$e =& $context->get('ErrorCollector');
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}
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// let's see if we can abort as quickly as possible
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// one equal sign, no spaces => one attribute
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$num_equal = substr_count($string, '=');
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$has_space = strpos($string, ' ');
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if ($num_equal === 0 && !$has_space) {
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// bool attribute
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return array($string => $string);
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} elseif ($num_equal === 1 && !$has_space) {
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// only one attribute
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list($key, $quoted_value) = explode('=', $string);
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$quoted_value = trim($quoted_value);
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if (!$key) {
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if ($e) {
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$e->send(E_ERROR, 'Lexer: Missing attribute key');
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}
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return array();
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}
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if (!$quoted_value) {
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return array($key => '');
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}
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$first_char = @$quoted_value[0];
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$last_char = @$quoted_value[strlen($quoted_value) - 1];
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$same_quote = ($first_char == $last_char);
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$open_quote = ($first_char == '"' || $first_char == "'");
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if ($same_quote && $open_quote) {
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// well behaved
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$value = substr($quoted_value, 1, strlen($quoted_value) - 2);
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} else {
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// not well behaved
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if ($open_quote) {
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if ($e) {
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$e->send(E_ERROR, 'Lexer: Missing end quote');
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}
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$value = substr($quoted_value, 1);
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} else {
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$value = $quoted_value;
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}
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}
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if ($value === false) {
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$value = '';
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}
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return array($key => $this->parseAttr($value, $config));
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}
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// setup loop environment
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$array = array(); // return assoc array of attributes
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$cursor = 0; // current position in string (moves forward)
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$size = strlen($string); // size of the string (stays the same)
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// if we have unquoted attributes, the parser expects a terminating
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// space, so let's guarantee that there's always a terminating space.
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$string .= ' ';
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$old_cursor = -1;
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while ($cursor < $size) {
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if ($old_cursor >= $cursor) {
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throw new Exception("Infinite loop detected");
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}
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$old_cursor = $cursor;
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$cursor += ($value = strspn($string, $this->_whitespace, $cursor));
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// grab the key
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$key_begin = $cursor; //we're currently at the start of the key
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// scroll past all characters that are the key (not whitespace or =)
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$cursor += strcspn($string, $this->_whitespace . '=', $cursor);
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$key_end = $cursor; // now at the end of the key
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$key = substr($string, $key_begin, $key_end - $key_begin);
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if (!$key) {
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if ($e) {
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$e->send(E_ERROR, 'Lexer: Missing attribute key');
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}
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$cursor += 1 + strcspn($string, $this->_whitespace, $cursor + 1); // prevent infinite loop
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continue; // empty key
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}
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// scroll past all whitespace
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$cursor += strspn($string, $this->_whitespace, $cursor);
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if ($cursor >= $size) {
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$array[$key] = $key;
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break;
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}
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// if the next character is an equal sign, we've got a regular
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// pair, otherwise, it's a bool attribute
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$first_char = @$string[$cursor];
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if ($first_char == '=') {
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// key="value"
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$cursor++;
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$cursor += strspn($string, $this->_whitespace, $cursor);
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if ($cursor === false) {
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$array[$key] = '';
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break;
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}
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// we might be in front of a quote right now
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$char = @$string[$cursor];
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if ($char == '"' || $char == "'") {
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// it's quoted, end bound is $char
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$cursor++;
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$value_begin = $cursor;
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$cursor = strpos($string, $char, $cursor);
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$value_end = $cursor;
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} else {
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// it's not quoted, end bound is whitespace
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$value_begin = $cursor;
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$cursor += strcspn($string, $this->_whitespace, $cursor);
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$value_end = $cursor;
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}
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// we reached a premature end
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if ($cursor === false) {
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$cursor = $size;
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$value_end = $cursor;
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}
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$value = substr($string, $value_begin, $value_end - $value_begin);
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if ($value === false) {
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$value = '';
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}
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$array[$key] = $this->parseAttr($value, $config);
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$cursor++;
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} else {
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// boolattr
|
|
if ($key !== '') {
|
|
$array[$key] = $key;
|
|
} else {
|
|
// purely theoretical
|
|
if ($e) {
|
|
$e->send(E_ERROR, 'Lexer: Missing attribute key');
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return $array;
|
|
}
|
|
}
|
|
|
|
// vim: et sw=4 sts=4
|