Class QCodec

src/main/java/org/apache/commons/codec/net/QCodec.java:51–357

Similar to the Quoted-Printable content-transfer-encoding defined in RFC 1521 and designed to allow text containing mostly ASCII characters to be decipherable on an ASCII terminal without decoding. RF

 * @since 1.3
 */
public class QCodec extends RFC1522Codec implements StringEncoder, StringDecoder {
    /**
     * The default Charset used for string decoding and encoding.
     */
    private final Charset charset;

    /**
     * BitSet of printable characters as defined in RFC 1522.
     */
    private static final BitSet PRINTABLE_CHARS = new BitSet(256);
    // Static initializer for printable chars collection
    static {
        // alpha characters
        PRINTABLE_CHARS.set(' ');
        PRINTABLE_CHARS.set('!');
        PRINTABLE_CHARS.set('"');
        PRINTABLE_CHARS.set('#');
        PRINTABLE_CHARS.set('$');
        PRINTABLE_CHARS.set('%');
        PRINTABLE_CHARS.set('&');
        PRINTABLE_CHARS.set('\'');
        PRINTABLE_CHARS.set('(');
        PRINTABLE_CHARS.set(')');
        PRINTABLE_CHARS.set('*');
        PRINTABLE_CHARS.set('+');
        PRINTABLE_CHARS.set(',');
        PRINTABLE_CHARS.set('-');
        PRINTABLE_CHARS.set('.');
        PRINTABLE_CHARS.set('/');
        for (int i = '0'; i <= '9'; i++) {
            PRINTABLE_CHARS.set(i);
        }
        PRINTABLE_CHARS.set(':');
        PRINTABLE_CHARS.set(';');
        PRINTABLE_CHARS.set('<');
        PRINTABLE_CHARS.set('>');
        PRINTABLE_CHARS.set('@');
        for (int i = 'A'; i <= 'Z'; i++) {
            PRINTABLE_CHARS.set(i);
        }
        PRINTABLE_CHARS.set('[');
        PRINTABLE_CHARS.set('\\');
        PRINTABLE_CHARS.set(']');
        PRINTABLE_CHARS.set('^');
        PRINTABLE_CHARS.set('`');
        for (int i = 'a'; i <= 'z'; i++) {
            PRINTABLE_CHARS.set(i);
        }
        PRINTABLE_CHARS.set('{');
        PRINTABLE_CHARS.set('|');
        PRINTABLE_CHARS.set('}');
        PRINTABLE_CHARS.set('~');
    }

    private static final byte SPACE = 32;

    private static final byte UNDERSCORE = 95;