/**
* Parses given sequence of bytes and constructs a message object from it.
*
* @param mesBytes the byte array that should be parsed
* @param startIdx an index of <code>mesBytes</code> array to start the parsing at
* @param mes an object to write a result to, should already be created
* @return updated index of <code>mesBytes</code> array
* @throws DomainProtocolException if some error has occurred
*/
public static int parseMessage(byte[] mesBytes, int startIdx, Message mesObj)
throws DomainProtocolException {
int idx = startIdx;
int tmp, tmp2;
int qdCnt;
int anCnt;
int nsCnt;
int arCnt;
if (mesObj == null) {
// jndi.58=The value of parameter mesObj is null
throw new DomainProtocolException(Messages.getString("jndi.58")); // $NON-NLS-1$
}
// header section
// ID
mesObj.setId(ProviderMgr.parse16Int(mesBytes, idx));
idx += 2;
// QR & opCode & AA & TC & RD & RA & Z & rCode
tmp = ProviderMgr.parse16Int(mesBytes, idx);
idx += 2;
// QR
mesObj.setQR(ProviderMgr.checkBit(tmp, ProviderConstants.QR_MASK));
// OPCODE
tmp2 = (tmp & ProviderConstants.OPCODE_MASK) >> ProviderConstants.OPCODE_SHIFT;
mesObj.setOpCode(tmp2);
// AA
mesObj.setAA(ProviderMgr.checkBit(tmp, ProviderConstants.AA_MASK));
// TC
mesObj.setTc(ProviderMgr.checkBit(tmp, ProviderConstants.TC_MASK));
// RD
mesObj.setRD(ProviderMgr.checkBit(tmp, ProviderConstants.RD_MASK));
// RA
mesObj.setRA(ProviderMgr.checkBit(tmp, ProviderConstants.RA_MASK));
// RCODE
tmp2 = (tmp & ProviderConstants.RCODE_MASK) >> ProviderConstants.RCODE_SHIFT;
mesObj.setRCode(tmp2);
// QDCOUNT
qdCnt = ProviderMgr.parse16Int(mesBytes, idx);
mesObj.setQDCount(qdCnt);
idx += 2;
// ANCOUNT
anCnt = ProviderMgr.parse16Int(mesBytes, idx);
mesObj.setANCount(anCnt);
idx += 2;
// NSCOUNT
nsCnt = ProviderMgr.parse16Int(mesBytes, idx);
mesObj.setNSCount(nsCnt);
idx += 2;
// ARCOUNT
arCnt = ProviderMgr.parse16Int(mesBytes, idx);
mesObj.setARCount(arCnt);
idx += 2;
// question section
for (int i = 0; i < qdCnt; i++) {
QuestionRecord qr = new QuestionRecord();
idx = QuestionRecord.parseRecord(mesBytes, idx, qr);
mesObj.addQuestionRecord(qr);
}
// answer section
for (int i = 0; i < anCnt; i++) {
ResourceRecord rr = new ResourceRecord();
idx = ResourceRecord.parseRecord(mesBytes, idx, rr);
mesObj.addAnswerRR(rr);
}
// authority section
for (int i = 0; i < nsCnt; i++) {
ResourceRecord rr = new ResourceRecord();
idx = ResourceRecord.parseRecord(mesBytes, idx, rr);
mesObj.addAuthorityRR(rr);
}
// additional section
for (int i = 0; i < arCnt; i++) {
ResourceRecord rr = new ResourceRecord();
idx = ResourceRecord.parseRecord(mesBytes, idx, rr);
mesObj.addAdditionalRR(rr);
}
return idx;
}
/**
* Generates sequence of bytes that represents the message.
*
* @param buffer the buffer to write bytes into
* @param startIdx the index of <code>buffer</code> to start writing at
* @return updated index of the <code>buffer</code>
* @throws DomainProtocolException if something went wrong
*/
public int writeBytes(byte[] buffer, int startIdx) throws DomainProtocolException {
int idx = startIdx;
int tmp = 0;
// basic check
if (buffer == null) {
// jndi.32=buffer is null
throw new DomainProtocolException(Messages.getString("jndi.32")); // $NON-NLS-1$
}
// ID
idx = ProviderMgr.write16Int(id, buffer, idx);
// QR
tmp = ProviderMgr.setBit(tmp, ProviderConstants.QR_MASK, qr);
// OPCODE
tmp &= ~ProviderConstants.OPCODE_MASK;
tmp |= (opCode & 0xf) << ProviderConstants.OPCODE_SHIFT;
// AA
tmp = ProviderMgr.setBit(tmp, ProviderConstants.AA_MASK, aa);
// TC
tmp = ProviderMgr.setBit(tmp, ProviderConstants.TC_MASK, tc);
// RD
tmp = ProviderMgr.setBit(tmp, ProviderConstants.RD_MASK, rd);
// RA
tmp = ProviderMgr.setBit(tmp, ProviderConstants.RA_MASK, ra);
// Z, drop all those bits
tmp &= ~ProviderConstants.Z_MASK;
// RCODE
tmp &= ~ProviderConstants.RCODE_MASK;
tmp |= (rCode & 0xf) << ProviderConstants.RCODE_SHIFT;
// write to buffer
idx = ProviderMgr.write16Int(tmp, buffer, idx);
// QDCOUNT
idx = ProviderMgr.write16Int(qdCount, buffer, idx);
// ANCOUNT
idx = ProviderMgr.write16Int(anCount, buffer, idx);
// NSCOUNT
idx = ProviderMgr.write16Int(nsCount, buffer, idx);
// ARCOUNT
idx = ProviderMgr.write16Int(arCount, buffer, idx);
// question section
for (int i = 0; i < questionRecords.size(); i++) {
QuestionRecord qr = questionRecords.elementAt(i);
idx = qr.writeBytes(buffer, idx);
}
// answer section
for (int i = 0; i < answerRRs.size(); i++) {
ResourceRecord rr = answerRRs.elementAt(i);
idx = rr.writeBytes(buffer, idx);
}
// authority section
for (int i = 0; i < authorityRRs.size(); i++) {
ResourceRecord rr = answerRRs.elementAt(i);
idx = rr.writeBytes(buffer, idx);
}
// additional section
for (int i = 0; i < additionalRRs.size(); i++) {
ResourceRecord rr = answerRRs.elementAt(i);
idx = rr.writeBytes(buffer, idx);
}
return idx;
}
