ITAPDLY_LENGTH
#define ITAPDLY_LAST_INDEX (ITAPDLY_LENGTH - 1)
if (fail_window->length == ITAPDLY_LENGTH) {
itap = (pass_window.start + (pass_window.length >> 1)) % ITAPDLY_LENGTH;
struct window fail_window[ITAPDLY_LENGTH];
for (itap = 0; itap < ITAPDLY_LENGTH; itap++) {