question: private static boolean decodeIpv4Suffix ( String input , int pos , int limit , byte [ ] address , int addressOffset ) { int b = addressOffset ; for ( int i = pos ; i < limit ; ) { if ( b == address . length ) return false ; if ( b != addressOffset ) { if ( input . charAt ( i ) != '.' ) return false ; i ++ ; } int value = 0 ; int groupOffset = i ; for ( ; i < limit ; i ++ ) { char c = input . charAt ( i ) ; if ( c < '0' || c > '9' ) break ; if ( value == 0 && groupOffset != i ) return false ; value = ( value * 10 ) + c - '0' ; if ( value > 255 ) return false ; } int groupLength = i - groupOffset ; if ( groupLength == 0 ) return false ; address [ b ++ ] = ( byte ) value ; } if ( b != addressOffset + 4 ) return false ; return true ; }
target:  Decodes an IPv4 address suffix of an IPv6 address, like 1111::5555:6666:192.168.0.1. 