SCAN_PURGE_READ_PASS
flags &= ~(SCAN_PURGE_READ_PASS
flags |= SCAN_PURGE_READ_PASS;
if (!(flags & SCAN_PURGE_READ_PASS)) {
if ((!(flags & SCAN_PURGE)) || (flags & SCAN_PURGE_READ_PASS)) {
if ((flags & SCAN_COMPARE) || (flags & SCAN_PURGE_READ_PASS)) {