code: public Long indexOf(File f, byte[] searchBytes, long fromPosition) {
  		return binFileSearcher.indexOf(f, searchBytes, fromPosition);
  	}
docs: Returns the index within this file of the first occurrence of the
  specified substring, starting at the specified position.
  
  @param f
  target file
  @param searchBytes
  a sequence of bytes you want to find
  @param fromPosition
  "0" means the beginning of the file
  @return position of the first occurence. '-1' means that it was not
  found.