question: public void appendValue ( String str ) { appendDoubleQuote ( ) ; byte [ ] data = str . getBytes ( DEFAULT_CHARSET ) ; int pos = 0 ; for ( int i = 0 ; i < data . length ; ++ i ) { int ch = data [ i ] & 0xFF ; if ( ( ch < ' ' ) || ( ch == '"' ) || ( ch == '\\' ) ) { append ( data , pos , i - pos ) ; pos = i + 1 ; if ( ch == '\n' ) { append ( NEWLINE ) ; } else if ( ch == '\t' ) { append ( HORIZONTAL_TAB ) ; } else if ( ch == '\r' ) { append ( CARRIAGE_RETURN ) ; } else if ( ch < ' ' ) { append ( UNICODE ) ; int nibble = 0xF000 ; int shift = 12 ; for ( int j = 0 ; j < 4 ; ++ j ) { int xch = ( ch & nibble ) > > shift ; if ( xch < 10 ) xch += '0' ; else xch = ( xch - 10 ) + 'A' ; hextmp [ j ] = ( byte ) xch ; shift -= 4 ; nibble >>= 4 ; } append ( hextmp ) ; } else { append ( BACKSLASH ) ; -- pos ; } } } append ( data , pos , data . length - pos ) ; appendDoubleQuote ( ) ; }
target:  Append a string adding surrounding double-quotes and doing any necessary escaping of control characters, double-quotes, and backslashes.