pat_scan
if (!(prest = pat_scan(p, pe, 0)))
pnext = pat_scan(psub, pe, 1);
if (!(prest = pat_scan(p, pe, 0)))
pnext = pat_scan(psub, pe, 1);
if (!(prest = pat_scan(p, pe, 0)))
pnext = pat_scan(psub, pe, 1);
const unsigned char *pat_scan(const unsigned char *, const unsigned char *,