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https://github.com/ezyang/htmlpurifier.git
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d886ed59fd
git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@600 48356398-32a2-884e-a903-53898d9a118a
309 lines
11 KiB
PHP
309 lines
11 KiB
PHP
<?php
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require_once 'HTMLPurifier/Lexer.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. It will support UTF-8
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* completely eventually.
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*
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* @todo Reread XML spec and document differences.
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*
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* @todo Determine correct behavior in transforming comment data. (preserve dashes?)
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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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* Whitespace characters for str(c)spn.
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* @protected
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*/
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var $_whitespace = "\x20\x09\x0D\x0A";
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function tokenizeHTML($html, $config, &$context) {
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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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// infinite loop protection
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// has to be pretty big, since html docs can be big
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// we're allow two hundred thousand tags... more than enough?
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$loops = 0;
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while(true) {
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// infinite loop protection
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if (++$loops > 200000) return array();
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$position_next_lt = strpos($html, '<', $cursor);
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$position_next_gt = strpos($html, '>', $cursor);
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// triggers on "<b>asdf</b>" but not "asdf <b></b>"
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if ($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 && $position_next_lt !== false) {
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// We are not inside tag and there still is another tag to parse
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$array[] = new
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HTMLPurifier_Token_Text(
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$this->parseData(
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substr(
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$html, $cursor, $position_next_lt - $cursor
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)
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)
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);
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$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($html)) break;
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// Create Text of rest of string
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$array[] = new
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HTMLPurifier_Token_Text(
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$this->parseData(
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substr(
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$html, $cursor
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)
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)
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);
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break;
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} elseif ($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 - $cursor;
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$segment = substr($html, $cursor, $strlen_segment);
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// Check if it's a comment
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if (
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substr($segment, 0, 3) == '!--' &&
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substr($segment, $strlen_segment-2, 2) == '--'
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) {
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$array[] = new
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HTMLPurifier_Token_Comment(
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substr(
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$segment, 3, $strlen_segment - 5
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)
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);
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$inside_tag = false;
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$cursor = $position_next_gt + 1;
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continue;
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}
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// Check if it's an end tag
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$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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$array[] = new HTMLPurifier_Token_End($type);
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$inside_tag = false;
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$cursor = $position_next_gt + 1;
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continue;
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}
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// Check if it is explicitly self closing, if so, remove
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// trailing slash. Remember, we could have a tag like <br>, so
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// any later token processing scripts must convert improperly
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// classified EmptyTags from StartTags.
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$is_self_closing= (strpos($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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$array[] = new HTMLPurifier_Token_Empty($segment);
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} else {
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$array[] = new HTMLPurifier_Token_Start($segment);
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}
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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, $position_first_space
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)
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);
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if ($attribute_string) {
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$attr = $this->parseAttributeString(
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$attribute_string
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, $config, $context
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);
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} else {
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$attr = array();
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}
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if ($is_self_closing) {
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$array[] = new HTMLPurifier_Token_Empty($type, $attr);
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} else {
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$array[] = new HTMLPurifier_Token_Start($type, $attr);
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}
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$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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$array[] = new
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HTMLPurifier_Token_Text(
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'<' .
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$this->parseData(
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substr($html, $cursor)
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)
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);
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break;
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}
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break;
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}
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return $array;
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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 $string Inside of tag excluding name.
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* @returns Assoc array of attributes.
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*/
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function parseAttributeString($string, $config, &$context) {
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$string = (string) $string; // quick typecast
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if ($string == '') return array(); // no attributes
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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) return array();
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if (!$quoted_value) return array($key => '');
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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 ($open_quote) {
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$value = substr($quoted_value, 1);
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} else {
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$value = $quoted_value;
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}
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}
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return array($key => $value);
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}
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// setup loop environment
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$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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// infinite loop protection
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$loops = 0;
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while(true) {
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// infinite loop protection
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if (++$loops > 1000) return array();
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if ($cursor >= $size) {
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break;
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}
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$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) continue; // empty key
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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, $cursor);
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// we might be in front of a quote right now
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$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 = $cursor;
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}
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$value = substr($string, $value_begin, $value_end - $value_begin);
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$array[$key] = $this->parseData($value);
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$cursor++;
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} else {
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// boolattr
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if ($key !== '') {
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$array[$key] = $key;
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}
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}
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}
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return $array;
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}
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}
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?>
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