private static int decodeBase31 ( @ Nonnull final String code ) { int value = 0 ; for ( final char c : code . toCharArray ( ) ) { if ( c == ' ' ) { return value ; } if ( DECODE_CHARS [ c ] < 0 ) { return - 1 ; } value = ( value * 31 ) + DECODE_CHARS [ c ] ; } return value ; }
returns negative in case of error