/**
* Copies the content of the most recently received packet into <tt>data</tt>.
*
* @param buffer an optional <tt>Buffer</tt> instance associated with the specified <tt>data</tt>,
* <tt>offset</tt> and <tt>length</tt> and provided to the method in case the implementation
* would like to provide additional <tt>Buffer</tt> properties such as <tt>flags</tt>
* @param data the <tt>byte[]</tt> that we'd like to copy the content of the packet to.
* @param offset the position where we are supposed to start writing in <tt>data</tt>.
* @param length the number of <tt>byte</tt>s available for writing in <tt>data</tt>.
* @return the number of bytes read
* @throws IOException if <tt>length</tt> is less than the size of the packet.
*/
protected int read(Buffer buffer, byte[] data, int offset, int length) throws IOException {
if (data == null) throw new NullPointerException("data");
if (ioError) return -1;
RawPacket pkt;
synchronized (pktSyncRoot) {
pkt = this.pkt;
this.pkt = null;
}
int pktLength;
if (pkt == null) {
pktLength = 0;
} else {
// By default, pkt will be returned to the pool after it was read.
boolean poolPkt = true;
try {
pktLength = pkt.getLength();
if (length < pktLength) {
/*
* If pkt is still the latest RawPacket made available to
* reading, reinstate it for the next invocation of read;
* otherwise, return it to the pool.
*/
poolPkt = false;
throw new IOException("Input buffer not big enough for " + pktLength);
} else {
byte[] pktBuffer = pkt.getBuffer();
if (pktBuffer == null) {
throw new NullPointerException(
"pkt.buffer null, pkt.length " + pktLength + ", pkt.offset " + pkt.getOffset());
} else {
System.arraycopy(pkt.getBuffer(), pkt.getOffset(), data, offset, pktLength);
if (buffer != null) buffer.setFlags(pkt.getFlags());
}
}
} finally {
if (!poolPkt) {
synchronized (pktSyncRoot) {
if (this.pkt == null) this.pkt = pkt;
else poolPkt = true;
}
}
if (poolPkt) {
// Return pkt to the pool because it was successfully read.
poolRawPacket(pkt);
}
}
}
return pktLength;
}
/**
* Adds a <tt>DatagramPacketFilter</tt> which allows dropping <tt>DatagramPacket</tt>s before they
* are converted into <tt>RawPacket</tt>s.
*
* @param datagramPacketFilter the <tt>DatagramPacketFilter</tt> which allows dropping
* <tt>DatagramPacket</tt>s before they are converted into <tt>RawPacket</tt>s
*/
public synchronized void addDatagramPacketFilter(DatagramPacketFilter datagramPacketFilter) {
if (datagramPacketFilter == null) throw new NullPointerException("datagramPacketFilter");
if (datagramPacketFilters == null) {
datagramPacketFilters = new DatagramPacketFilter[] {datagramPacketFilter};
} else {
final int length = datagramPacketFilters.length;
for (int i = 0; i < length; i++)
if (datagramPacketFilter.equals(datagramPacketFilters[i])) return;
DatagramPacketFilter[] newDatagramPacketFilters = new DatagramPacketFilter[length + 1];
System.arraycopy(datagramPacketFilters, 0, newDatagramPacketFilters, 0, length);
newDatagramPacketFilters[length] = datagramPacketFilter;
datagramPacketFilters = newDatagramPacketFilters;
}
}