private String unwrapBytes(
ByteBuffer[] dsts, int offset, int length, ByteBuffer src, boolean readHandshakeMsg) {
// define unwrapped data to be written to dsts
String wrapped = new String(Buffers.take(src), StandardCharsets.ISO_8859_1);
int wrappedEndIndex = wrapped.length();
int wrappedLeftOver = -1;
while (wrappedEndIndex > 0 && !unwrapMap.containsKey(wrapped.substring(0, wrappedEndIndex))) {
wrappedLeftOver = wrappedEndIndex--;
}
// undo the reading of data that won't be used now
if (wrappedLeftOver != -1 && wrappedEndIndex > 0) {
src.position(src.position() - (wrapped.length() - wrappedEndIndex));
wrapped = wrapped.substring(0, wrappedEndIndex);
} else {
int msgIndex;
if ((msgIndex = wrapped.indexOf(HANDSHAKE_MSG)) != -1) {
if (msgIndex == 0) {
src.position(src.position() - (wrapped.length() - HANDSHAKE_MSG.length()));
wrapped = wrapped.substring(0, HANDSHAKE_MSG.length());
} else {
src.position(src.position() - (wrapped.length() - msgIndex));
wrapped = wrapped.substring(0, msgIndex);
}
}
if ((msgIndex = wrapped.indexOf(CLOSE_MSG)) != -1) {
if (msgIndex == 0) {
src.position(src.position() - (wrapped.length() - CLOSE_MSG.length()));
wrapped = wrapped.substring(0, CLOSE_MSG.length());
} else {
src.position(src.position() - (wrapped.length() - msgIndex));
wrapped = wrapped.substring(0, msgIndex);
}
}
}
String unwrapped = unwrapMap.containsKey(wrapped) ? unwrapMap.get(wrapped) : wrapped;
if (unwrapped.equals(HANDSHAKE_MSG) && !readHandshakeMsg) {
src.position(src.position() - wrapped.length());
return "";
}
if (!unwrapped.equals(CLOSE_MSG) && !unwrapped.equals(HANDSHAKE_MSG)) {
if (CLOSE_MSG.startsWith(unwrapped) || HANDSHAKE_MSG.startsWith(unwrapped)) {
src.position(0);
return null;
}
// check if there is enough space to write unwrapped data, if not, do not write
if (Buffers.remaining(dsts, offset, length) < unwrapped.length()) {
src.position(src.position() - wrapped.length());
return null;
}
// copy data to dsts
Buffers.copy(
dsts, offset, length, ByteBuffer.wrap(unwrapped.getBytes(StandardCharsets.ISO_8859_1)));
}
return unwrapped;
}
