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html_parse.inc.php
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<?php
/**
* html_parse.inc.php
* Generic html parsing functions
*
* Copyright Gottfried Haider, Danja Vasiliev 2010.
* This source code is licensed under the GNU General Public License.
* See the file COPYING for more details.
*/
@require_once('config.inc.php');
require_once('html.inc.php');
require_once('util.inc.php');
function html_encode_str_smart($html)
{
// TODO (later): remove debug code
log_msg('debug', 'html_encode_str_smart: string is '.quot(var_dump_inl($html)));
// encode ampersand characters where needed
$cur = 0;
while ($cur < strlen($html)) {
// check &
if (substr($html, $cur, 1) == '&') {
$replace = true;
// DEBUG
$reason = false;
// check &#??
if ($cur+3 < strlen($html) && substr($html, $cur+1, 1) == '#') {
// check $#x or not
if (strtolower(substr($html, $cur+2, 1)) == 'x') {
// check for hexadecimal characters before ;
$ahead = $cur+3;
while ($ahead < strlen($html)) {
$char = strtolower(substr($html, $ahead, 1));
if ((48 <= ord($char) && ord($char) <= 57) || (97 <= ord($char) && ord($char) <= 102)) {
// valid hexadecimal character
$ahead++;
} elseif ($char == ';') {
if ($cur+3 < $ahead) {
// valid entitiy
$replace = false;
break;
} else {
// invalid entity
// DEBUG
$reason = 1;
break;
}
} else {
// invalid entity
// DEBUG
$reason = 2;
break;
}
}
if ($ahead == strlen($html)) {
// DEBUG
$reason = 3;
}
} elseif (is_numeric(substr($html, $cur+2, 1))) {
// check for for decimal characters before ;
$ahead = $cur+3;
while ($ahead < strlen($html)) {
$char = substr($html, $ahead, 1);
if (48 <= ord($char) && ord($char) <= 57) {
// valid decimal character
$ahead++;
} elseif ($char == ';') {
// valid entity
$replace = false;
break;
} else {
// invalid entity
$reason = 4;
break;
}
}
if ($ahead == strlen($html)) {
// DEBUG
$reason = 5;
}
} else {
// DEBUG
$reson = 6;
}
} else {
// assume a named entity
// it turns out we can't use get_html_translation_table()
// for this as the HTML_ENTITIES table is not complete
$ahead = $cur+1;
while ($ahead < strlen($html)) {
$char = strtolower(substr($html, $ahead, 1));
if ((48 <= ord($char) && ord($char) <= 57) || (97 <= ord($char) && ord($char) <= 122)) {
// valid alphanumeric character
$ahead++;
} elseif ($char == ';') {
if ($cur+1 < $ahead) {
// (supposedly) valid entity
$replace = false;
break;
} else {
// invalid entity
// DEBUG
$reason = 7;
break;
}
} else {
// invalid entity
// DEBUG
$reason = 8;
break;
}
}
if ($ahead == strlen($html)) {
$reason = 9;
break;
}
}
if ($replace) {
log_msg('debug', 'html_encode_str_smart: replacing ampersand at '.$cur.' because of '.$reason);
$html = substr($html, 0, $cur).'&amp;'.substr($html, $cur+1);
log_msg('debug', 'html_encode_str_smart: new string is '.quot(var_dump_inl($html)));
$cur += 5;
} else {
log_msg('debug', 'html_encode_str_smart: not replacing ampersand at '.$cur);
$cur++;
}
} else {
$cur++;
}
}
// encode < and > where needed
$cur = 0;
while ($cur < strlen($html)) {
$char = substr($html, $cur, 1);
$replace = true;
if ($char == '<') {
// a possible tag
// search for a closing bracket
$ahead = $cur+1;
while ($ahead < strlen($html)) {
$c = strtolower(substr($html, $ahead, 1));
if ($c == '<') {
// found another opening bracket
// the first one can't be legit
// DEBUG
$reason = 1;
break;
} elseif ($c == '>') {
if ($cur+1 < $ahead) {
// can be a valid tag
$replace = false;
// forward till after the closing bracket
$cur = $ahead;
break;
} else {
// invalid (empty) tag
// DEBUG
$reason = 2;
break;
}
} elseif ($ahead == $cur+1) {
if ((48 <= ord($c) && ord($c) <= 57) || (97 <= ord($c) && ord($c) <= 122) || $c == '/') {
// starts with an alphanumeric character or a slash, can be valid
} else {
// DEBUG
$reason = 3;
break;
}
}
$ahead++;
}
if ($ahead == strlen($html)) {
// DEBUG
$reason = 4;
}
} else if ($char == '>') {
// we should be getting all valid tags through the code above
// DEBUG
$reason = 5;
}
if ($replace && $char == '<') {
log_msg('debug', 'html_encode_str_smart: replacing opening bracket at '.$cur.' because of '.$reason);
$html = substr($html, 0, $cur).'&lt;'.substr($html, $cur+1);
log_msg('debug', 'html_encode_str_smart: new string is '.quot(var_dump_inl($html)));
$cur += 4;
} elseif ($replace && $char == '>') {
log_msg('debug', 'html_encode_str_smart: replacing closing bracket at '.$cur.' because of '.$reason);
$html = substr($html, 0, $cur).'&gt;'.substr($html, $cur+1);
log_msg('debug', 'html_encode_str_smart: new string is '.quot(var_dump_inl($html)));
$cur += 4;
} else {
$cur++;
}
}
return $html;
}
/**
* parse a string containing html elements
*
* this function decodes html's special characters except for the content
* (when it too is not being parsed).
* this function is more fragile than html_parse_elem() when it comes to
* malformatted input.
* @param string $html input string
* @param bool $recursive also parse children elements
* @return array parsed representation
*/
function html_parse($html, $recursive = false)
{
global $single_tags; // from html.inc.php
$ret = array();
$pos = 0;
$open_tag = false;
$open_pos = false;
// can probably be done with -1 and some slightly easier code below
$close_pos = false;
$num_open = 0;
while ($pos < strlen($html)) {
if ($html[$pos] == '<') {
if (($next = strpos($html, '>', $pos+1)) === false) {
// error: unclosed <
$pos++;
continue;
}
// handle uppercase tags as well
$tag = strtolower(trim(substr($html, $pos+1, $next-$pos-1)));
if (substr($tag, 0, 1) !== '/') {
// opening tag
if ($num_open == 0) {
$a = expl_whitesp($tag, true);
$open_tag = $a[0];
$open_pos = $pos;
}
// handle single tags
if (in_array($tag, $single_tags)) {
if ($num_open == 0) {
// check if there was something between the last $close_pos and $open_pos
$text = '';
if ($close_pos === false && 0 < $open_pos) {
$text = trim(substr($html, 0, $open_pos));
} elseif ($close_pos !== false && $close_pos+1 < $open_pos) {
$text = trim(substr($html, $close_pos+1, $open_pos-$close_pos-1));
}
if (0 < strlen($text)) {
$ret[] = $text;
}
$close_pos = $next;
$ret[] = html_parse_elem(substr($html, $open_pos, $close_pos-$open_pos+1), $recursive);
}
} else {
$num_open++;
}
} else {
// closing tag
$num_open--;
if ($num_open == 0) {
// check if opening and closing tag match
if ($open_tag != substr($tag, 1)) {
// error: opening and closing tag do not match
$pos++;
continue;
}
// check if there was something between the last $close_pos and $open_pos
$text = '';
if ($close_pos === false && 0 < $open_pos) {
$text = trim(substr($html, 0, $open_pos));
} elseif ($close_pos !== false && $close_pos+1 < $open_pos) {
$text = trim(substr($html, $close_pos+1, $open_pos-$close_pos-1));
}
if (0 < strlen($text)) {
$ret[] = $text;
}
$close_pos = $next;
$ret[] = html_parse_elem(substr($html, $open_pos, $close_pos-$open_pos+1), $recursive);
}
}
}
$pos++;
}
// check if there was something after the last $close_pos
$text = '';
if ($close_pos === false && 1 < $pos) {
$text = trim($html);
} elseif ($close_pos !== false && $close_pos+1 < $pos) {
$text = trim(substr($html, $close_pos+1));
}
if (0 < strlen($text)) {
$ret[] = $text;
}
return $ret;
}
/**
* parse exactly one html element
*
* this function decodes html's special characters except for the content
* (when it too is not being parsed).
* this function is less fragile than html_parse() when it comes to
* malformatted input.
* @param string $html input string (must start and end with the element's tag)
* @param bool $recursive also parse children elements
* @return array parsed representation
*/
function html_parse_elem($html, $recursive = false)
{
global $single_tags; // from html.inc.php
$quot = array('"', "'");
$ret = array();
// explode the tag
$next = strpos($html, '>', 1);
$a = expl_whitesp(substr($html, 1, $next-1), true);
if (count($a) < 1) {
return $ret;
} else {
$ret['tag'] = strtolower($a[0]);
}
// attributes can end up in one to three fields
// combine them
for ($i=1; $i < count($a); $i++) {
if ($a[$i] == '=' && 1 < $i && $i+1 < count($a)) {
$a[$i] = $a[$i-1].'='.$a[$i+1];
array_splice($a, $i-1, 1);
array_splice($a, $i, 1);
$i--;
} elseif (substr($a[$i], -1) == '=' && $i+1 < count($a)) {
$a[$i] .= $a[$i+1];
array_splice($a, $i+1, 1);
$i--;
} elseif (substr($a[$i], 0, 1) == '=' && 1 < $i) {
$a[$i] = $a[$i-1].$a[$i];
array_splice($a, $i-1, 1);
$i--;
}
}
// put attributes into array
for ($i=1; $i < count($a); $i++) {
if (($equal = strpos($a[$i], '=')) === false) {
$attr = strtolower(htmlspecialchars_decode($a[$i], ENT_QUOTES));
$ret[$attr] = $attr;
} else {
$attr = strtolower(htmlspecialchars_decode(substr($a[$i], 0, $equal), ENT_QUOTES));
$val = htmlspecialchars_decode(substr($a[$i], $equal+1), ENT_QUOTES);
// strip optional quotes
if (in_array(substr($val, 0, 1), $quot) && substr($val, 0, 1) == substr($val, -1)) {
$val = substr($val, 1, -1);
}
// special cases for certain attributes
if ($attr == 'class') {
$val = expl(' ', $val);
} elseif ($attr == 'style') {
$styles = expl(';', $val);
$val = array();
foreach ($styles as $style) {
$temp = expl(':', $style);
if (1 < count($temp)) {
$val[strtolower(trim($temp[0]))] = trim(implode(':', array_slice($temp, 1)));
}
}
}
$ret[$attr] = $val;
}
}
// handle content
if (!in_array($ret['tag'], $single_tags)) {
// check if there is actually a closing tag
if (($last = strrpos($html, '<')) !== false) {
// check if opening and closing tags match
if (strtolower(substr($html, $last+2, -1)) == $ret['tag']) {
$ret['val'] = trim(substr($html, $next+1, $last-$next-1));
if ($recursive) {
$ret['val'] = html_parse($ret['val'], true);
}
}
}
}
return $ret;
}
?>

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