/**
* Blocks and reads into a <tt>Buffer</tt> from this <tt>PullBufferStream</tt>.
*
* @param buffer the <tt>Buffer</tt> this <tt>PullBufferStream</tt> is to read into
* @throws IOException if an I/O error occurs while this <tt>PullBufferStream</tt> reads into the
* specified <tt>Buffer</tt>
* @see AbstractVideoPullBufferStream#doRead(Buffer)
*/
@Override
protected void doRead(Buffer buffer) throws IOException {
/*
* Determine the Format in which we're expected to output. We cannot
* rely on the Format always being specified in the Buffer because it is
* not its responsibility, the DataSource of this ImageStream knows the
* output Format.
*/
Format format = buffer.getFormat();
if (format == null) {
format = getFormat();
if (format != null) buffer.setFormat(format);
}
if (format instanceof AVFrameFormat) {
Object o = buffer.getData();
AVFrame frame;
if (o instanceof AVFrame) frame = (AVFrame) o;
else {
frame = new AVFrame();
buffer.setData(frame);
}
AVFrameFormat avFrameFormat = (AVFrameFormat) format;
Dimension size = avFrameFormat.getSize();
ByteBuffer data = readScreenNative(size);
if (data != null) {
if (frame.avpicture_fill(data, avFrameFormat) < 0) {
data.free();
throw new IOException("avpicture_fill");
}
} else {
/*
* This can happen when we disconnect a monitor from computer
* before or during grabbing.
*/
throw new IOException("Failed to grab screen.");
}
} else {
byte[] bytes = (byte[]) buffer.getData();
Dimension size = ((VideoFormat) format).getSize();
bytes = readScreen(bytes, size);
buffer.setData(bytes);
buffer.setOffset(0);
buffer.setLength(bytes.length);
}
buffer.setHeader(null);
buffer.setTimeStamp(System.nanoTime());
buffer.setSequenceNumber(seqNo);
buffer.setFlags(Buffer.FLAG_SYSTEM_TIME | Buffer.FLAG_LIVE_DATA);
seqNo++;
}
/**
* 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;
}
