98 lines
3.3 KiB
PHP
98 lines
3.3 KiB
PHP
<?php
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/**
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* Class that handles operations involving percent-encoding in URIs.
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*
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* @warning
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* Be careful when reusing instances of PercentEncoder. The object
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* you use for normalize() SHOULD NOT be used for encode(), or
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* vice-versa.
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*/
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class HTMLPurifier_PercentEncoder
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{
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/**
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* Reserved characters to preserve when using encode().
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*/
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protected $preserve = array();
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/**
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* String of characters that should be preserved while using encode().
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*/
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public function __construct($preserve = false) {
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// unreserved letters, ought to const-ify
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for ($i = 48; $i <= 57; $i++) $this->preserve[$i] = true; // digits
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for ($i = 65; $i <= 90; $i++) $this->preserve[$i] = true; // upper-case
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for ($i = 97; $i <= 122; $i++) $this->preserve[$i] = true; // lower-case
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$this->preserve[45] = true; // Dash -
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$this->preserve[46] = true; // Period .
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$this->preserve[95] = true; // Underscore _
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$this->preserve[126]= true; // Tilde ~
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// extra letters not to escape
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if ($preserve !== false) {
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for ($i = 0, $c = strlen($preserve); $i < $c; $i++) {
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$this->preserve[ord($preserve[$i])] = true;
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}
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}
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}
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/**
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* Our replacement for urlencode, it encodes all non-reserved characters,
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* as well as any extra characters that were instructed to be preserved.
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* @note
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* Assumes that the string has already been normalized, making any
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* and all percent escape sequences valid. Percents will not be
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* re-escaped, regardless of their status in $preserve
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* @param $string String to be encoded
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* @return Encoded string.
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*/
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public function encode($string) {
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$ret = '';
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for ($i = 0, $c = strlen($string); $i < $c; $i++) {
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if ($string[$i] !== '%' && !isset($this->preserve[$int = ord($string[$i])]) ) {
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$ret .= '%' . sprintf('%02X', $int);
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} else {
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$ret .= $string[$i];
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}
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}
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return $ret;
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}
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/**
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* Fix up percent-encoding by decoding unreserved characters and normalizing.
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* @warning This function is affected by $preserve, even though the
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* usual desired behavior is for this not to preserve those
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* characters. Be careful when reusing instances of PercentEncoder!
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* @param $string String to normalize
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*/
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public function normalize($string) {
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if ($string == '') return '';
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$parts = explode('%', $string);
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$ret = array_shift($parts);
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foreach ($parts as $part) {
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$length = strlen($part);
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if ($length < 2) {
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$ret .= '%25' . $part;
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continue;
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}
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$encoding = substr($part, 0, 2);
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$text = substr($part, 2);
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if (!ctype_xdigit($encoding)) {
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$ret .= '%25' . $part;
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continue;
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}
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$int = hexdec($encoding);
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if (isset($this->preserve[$int])) {
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$ret .= chr($int) . $text;
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continue;
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}
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$encoding = strtoupper($encoding);
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$ret .= '%' . $encoding . $text;
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}
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return $ret;
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}
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}
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// vim: et sw=4 sts=4
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