WordPress 3.9.2

[autoinstalls/wordpress.git] / wp-includes / compat.php

diff --git a/wp-includes/compat.php b/wp-includes/compat.php
index cb2a5597c8cde15867682100cfbf507a2016bc6d..83a8c64652b4679b720df879e02ac903e75e7d42 100644 (file)
--- a/wp-includes/compat.php
+++ b/wp-includes/compat.php
@@ -94,3 +94,32 @@ if ( !function_exists('json_decode') ) {
                return is_array($data) ? array_map(__FUNCTION__, $data) : $data;
        }
 }
+
+if ( ! function_exists( 'hash_equals' ) ) :
+/**
+ * Compare two strings in constant time.
+ *
+ * This function was added in PHP 5.6.
+ * It can leak the length of a string.
+ *
+ * @since 3.9.2
+ *
+ * @param string $a Expected string.
+ * @param string $b Actual string.
+ * @return bool Whether strings are equal.
+ */
+function hash_equals( $a, $b ) {
+       $a_length = strlen( $a );
+       if ( $a_length !== strlen( $b ) ) {
+               return false;
+       }
+       $result = 0;
+
+       // Do not attempt to "optimize" this.
+       for ( $i = 0; $i < $a_length; $i++ ) {
+               $result |= ord( $a[ $i ] ) ^ ord( $b[ $i ] );
+       }
+
+       return $result === 0;
+}
+endif;
\ No newline at end of file