StringScanner#scan_byte

static VALUE
strscan_scan_byte(VALUE self)
{
    struct strscanner *p;
    VALUE byte;

    GET_SCANNER(self, p);
    CLEAR_MATCH_STATUS(p);
    if (EOS_P(p))
        return Qnil;

    byte = INT2FIX((unsigned char)*CURPTR(p));
    p->prev = p->curr;
    p->curr++;
    MATCHED(p);
    adjust_registers_to_matched(p);
    return byte;
}