question: static byte [ ] septetStream2octetStream ( byte [ ] septets ) { int octetLength = ( int ) Math . ceil ( ( ( septets . length * 7 ) ) / 8.0 ) ; byte [ ] octets = new byte [ octetLength ] ; for ( int i = 0 ; i < septets . length ; i ++ ) { for ( int j = 0 ; j < 7 ; j ++ ) { if ( ( septets [ i ] & ( 1 << j ) ) != 0 ) { int bitIndex = ( i * 7 ) + j ; octets [ bitIndex > > > 3 ] |= 1 << ( bitIndex & 7 ) ; } } } return octets ; }
target:  Convert a list of septet values into an octet stream, with a number of empty bits at the start.