code: public long skip(long numbytes) throws IOException {
          if (numbytes <= 0) {
              return 0;
          }
          long n = numbytes;
          int buflen = (int) Math.min(1024, n);
          byte data[] = new byte[buflen];
          while (n > 0) {
              int r = read(data, 0, (int) Math.min((long) buflen, n));
              if (r < 0) {
                  break;
              }
              n -= r;
          }
          return numbytes - n;
      }
docs: Skips n bytes of input.
  @param numbytes the number of bytes to skip
  @return  the actual number of bytes skipped.
  @exception IOException If an I/O error has occurred.