private void shiftSeqData(int start,int len,int shift){
  if (shift > 0) {
    ensureFreeBytes(shift);
  }
  System.arraycopy(buf,start,buf,start + shift,len);
  offset+=shift;
}

private void shiftSeqData ( int start , int len , int shift ) { if ( shift > 0 ) { ensureFreeBytes ( shift ) ; } System . arraycopy ( buf , start , buf , start + shift , len ) ; offset += shift ; }
shifts contents of buf in the range [ start , start + len ) a specified amount . positive shift value means shift to the right .
