code: public static int getOctalBytes(long value, byte[] buf, int offset, int length) {
          int idx = length - 1;
  
          buf[offset + idx] = 0;
          --idx;
          buf[offset + idx] = (byte) ' ';
          --idx;
  
          if (value == 0) {
              buf[offset + idx] = (byte) '0';
              --idx;
          } else {
              for (long val = value; idx >= 0 && val > 0; --idx) {
                  buf[offset + idx] = (byte) ((byte) '0' + (byte) (val & 7));
                  val = val >> 3;
              }
          }
  
          for (; idx >= 0; --idx) {
              buf[offset + idx] = (byte) ' ';
          }
  
          return offset + length;
      }
docs: Parse an octal integer from a header buffer.
  
  @param header
  The header buffer from which to parse.
  @param offset
  The offset into the buffer from which to parse.
  @param length
  The number of header bytes to parse.
  @return The integer value of the octal bytes.