@Override
protected byte[] doEncoding(byte[] bytes) {
if (bytes == null) {
return null;
}
byte[] data = QuotedPrintableCodec.encodeQuotedPrintable(PRINTABLE_CHARS, bytes);
if (this.encodeBlanks) {
for (int i = 0; i < data.length; i++) {
if (data[i] == BLANK) {
data[i] = UNDERSCORE;
}
}
}
return data;
}
/**
* Encodes an array of bytes into an array of quoted-printable 7-bit characters. Unsafe characters
* are escaped.
*
* <p>This function implements a subset of quoted-printable encoding specification (rule #1 and
* rule #2) as defined in RFC 1521 and is suitable for encoding binary data and unformatted text.
*
* @param printable bitset of characters deemed quoted-printable
* @param bytes array of bytes to be encoded
* @return array of bytes containing quoted-printable data
*/
public static final byte[] encodeQuotedPrintable(BitSet printable, byte[] bytes) {
if (bytes == null) {
return null;
}
if (printable == null) {
printable = PRINTABLE_CHARS;
}
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
for (int i = 0; i < bytes.length; i++) {
int b = bytes[i];
if (b < 0) {
b = 256 + b;
}
if (printable.get(b)) {
buffer.write(b);
} else {
encodeQuotedPrintable(b, buffer);
}
}
return buffer.toByteArray();
}
/**
* Encodes an array of bytes into an array of quoted-printable 7-bit characters. Unsafe characters
* are escaped.
*
* <p>Depending on the selection of the {@code strict} parameter, this function either implements
* the full ruleset or only a subset of quoted-printable encoding specification (rule #1 and rule
* #2) as defined in RFC 1521 and is suitable for encoding binary data and unformatted text.
*
* @param printable bitset of characters deemed quoted-printable
* @param bytes array of bytes to be encoded
* @param strict if {@code true} the full ruleset is used, otherwise only rule #1 and rule #2
* @return array of bytes containing quoted-printable data
* @since 1.10
*/
public static final byte[] encodeQuotedPrintable(
BitSet printable, final byte[] bytes, boolean strict) {
if (bytes == null) {
return null;
}
if (printable == null) {
printable = PRINTABLE_CHARS;
}
final ByteArrayOutputStream buffer = new ByteArrayOutputStream();
if (strict) {
int pos = 1;
// encode up to buffer.length - 3, the last three octets will be treated
// separately for simplification of note #3
for (int i = 0; i < bytes.length - 3; i++) {
int b = getUnsignedOctet(i, bytes);
if (pos < SAFE_LENGTH) {
// up to this length it is safe to add any byte, encoded or not
pos += encodeByte(b, !printable.get(b), buffer);
} else {
// rule #3: whitespace at the end of a line *must* be encoded
encodeByte(b, !printable.get(b) || isWhitespace(b), buffer);
// rule #5: soft line break
buffer.write(ESCAPE_CHAR);
buffer.write(CR);
buffer.write(LF);
pos = 1;
}
}
// rule #3: whitespace at the end of a line *must* be encoded
// if we would do a soft break line after this octet, encode whitespace
int b = getUnsignedOctet(bytes.length - 3, bytes);
boolean encode = !printable.get(b) || (isWhitespace(b) && pos > SAFE_LENGTH - 5);
pos += encodeByte(b, encode, buffer);
// note #3: '=' *must not* be the ultimate or penultimate character
// simplification: if < 6 bytes left, do a soft line break as we may need
// exactly 6 bytes space for the last 2 bytes
if (pos > SAFE_LENGTH - 2) {
buffer.write(ESCAPE_CHAR);
buffer.write(CR);
buffer.write(LF);
}
for (int i = bytes.length - 2; i < bytes.length; i++) {
b = getUnsignedOctet(i, bytes);
// rule #3: trailing whitespace shall be encoded
encode = !printable.get(b) || (i > bytes.length - 2 && isWhitespace(b));
encodeByte(b, encode, buffer);
}
} else {
for (final byte c : bytes) {
int b = c;
if (b < 0) {
b = 256 + b;
}
if (printable.get(b)) {
buffer.write(b);
} else {
encodeQuotedPrintable(b, buffer);
}
}
}
return buffer.toByteArray();
}
