+ // calculate boundary in case of multidimensional mime structures
+ if ($boundary && $message->entity_id && count($message->entities)) {
+ if (strpos($boundary,'_part_')) {
+ $boundary = substr($boundary,0,strpos($boundary,'_part_'));
+
+ // the next four lines use strrev to reverse any nested boundaries
+ // because RFC 2046 (5.1.1) says that if a line starts with the outer
+ // boundary string (doesn't matter what the line ends with), that
+ // can be considered a match for the outer boundary; thus the nested
+ // boundary needs to be unique from the outer one
+ //
+ } else if (strpos($boundary,'_trap_')) {
+ $boundary = substr(strrev($boundary),0,strpos(strrev($boundary),'_part_'));
+ }
+ $boundary_new = strrev($boundary . '_part_'.$message->entity_id);
+ } else {
+ $boundary_new = $boundary;
+ }