BADCHAR
sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
if (wc == BADCHAR)
sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
if (wc == BADCHAR || !CHIN(cs, wc))
clen = XMBRTOWC(&c, p, m->endp - p, &m->mbs, BADCHAR);