public static String trimUrl(final StringBuilder s) {
        final String s1 = trimBy(s, 4, 1).trim();
        if (s1.length() == 0) {
            return s1;
        }

        final int end = s1.length() - 1;
        final char c0 = s1.charAt(0);
        if ((c0 == '"' && s1.charAt(end) == '"')
            || (c0 == '\'' && s1.charAt(end) == '\'')) {
            return s1.substring(1, end);
        }

        return s1;
    }
public static String trimUrl ( final StringBuilder s ) { final String s1 = trimBy ( s , 4 , 1 ) . trim ( ) ; if ( s1 . length ( ) == 0 ) { return s1 ; } final int end = s1 . length ( ) - 1 ; final char c0 = s1 . charAt ( 0 ) ; if ( ( c0 == '"' && s1 . charAt ( end ) == '"' ) || ( c0 == '\'' && s1 . charAt ( end ) == '\'' ) ) { return s1 . substring ( 1 , end ) ; } return s1 ; }
Helper that removes the leading "url(", the trailing ")"
and surrounding quotes from the given string builder.
@param s the StringBuilder
@return the trimmed string