offtout
offtout(0, header + 8);
offtout(0, header + 16);
offtout(newsize, header + 24);
offtout(lenf,buf);
offtout((scan-lenb)-(lastscan+lenf),buf);
offtout((pos-lenb)-(lastpos+lenf),buf);
offtout(len-32, header + 8);
offtout(xnewsize - len, header + 16);