/* slices a read only contiguous buffer of chunkLength */
private ByteBuffer slice(int chunkLength)
{
int len = chunkLength;
long oldOffset = currentOffset;
ByteBuffer slice;
if (compressed.remaining() >= len)
{
slice = compressed.slice();
// simple case
slice.limit(len);
currentOffset += len;
compressed.position(compressed.position() + len);
return slice;
}
else if (currentRange >= (bytes.Count - 1))
{
// nothing has been modified yet
throw new IOException("EOF in " + this + " while trying to read " +
chunkLength + " bytes");
}
if (LOG.isDebugEnabled())
{
LOG.debug(String.Format(
"Crossing into next BufferChunk because compressed only has %d bytes (needs %d)",
compressed.remaining(), len));
}
// we need to consolidate 2 or more buffers into 1
// first copy out compressed buffers
ByteBuffer copy = allocateBuffer(chunkLength, compressed.isDirect());
currentOffset += compressed.remaining();
len -= compressed.remaining();
copy.put(compressed);
for (int i = currentRange; i < bytes.Count && len > 0; i++)
{
++currentRange;
if (LOG.isDebugEnabled())
{
LOG.debug(String.Format("Read slow-path, >1 cross block reads with {0}", this.ToString()));
}
DiskRange range = bytes[i];
compressed = range.getData().duplicate();
if (compressed.remaining() >= len)
{
slice = compressed.slice();
slice.limit(len);
copy.put(slice);
currentOffset += len;
compressed.position(compressed.position() + len);
return copy;
}
currentOffset += compressed.remaining();
len -= compressed.remaining();
copy.put(compressed);
}
// restore offsets for exception clarity
seek(oldOffset);
throw new IOException("EOF in " + this + " while trying to read " +
chunkLength + " bytes");
}
/// <summary>
/// Continue to read data until the end of an element, then call
/// elementListener.onReceivedElement(element ). The buffer passed to
/// onReceivedElement is only valid during this call. If you need the data
/// later, you must copy.
/// </summary>
///
/// <param name="data"></param>
/// <exception cref="EncodingException">For invalid encoding.</exception>
public void onReceivedData(ByteBuffer data)
{
// We may repeatedly set data to a slice as we read elements.
data = data.slice();
// Process multiple objects in the data.
while (true) {
bool gotElementEnd;
int offset;
try {
if (!usePartialData_) {
// This is the beginning of an element.
if (data.remaining() <= 0)
// Wait for more data.
return;
}
// Scan the input to check if a whole TLV object has been read.
tlvStructureDecoder_.seek(0);
gotElementEnd = tlvStructureDecoder_.findElementEnd(data);
offset = tlvStructureDecoder_.getOffset();
} catch (EncodingException ex) {
// Reset to read a new element on the next call.
usePartialData_ = false;
tlvStructureDecoder_ = new TlvStructureDecoder();
throw ex;
}
if (gotElementEnd) {
// Got the remainder of an element. Report to the caller.
ByteBuffer element;
if (usePartialData_) {
// We have partial data from a previous call, so append this data and point to partialData.
partialData_.ensuredPut(data, 0, offset);
element = partialData_.flippedBuffer();
// Assume we don't need to use partialData anymore until needed.
usePartialData_ = false;
} else {
// We are not using partialData, so just point to the input data buffer.
element = data.duplicate();
element.limit(offset);
}
// Reset to read a new object. Do this before calling onReceivedElement
// in case it throws an exception.
data.position(offset);
data = data.slice();
tlvStructureDecoder_ = new TlvStructureDecoder();
elementListener_.onReceivedElement(element);
if (data.remaining() <= 0)
// No more data in the packet.
return;
// else loop back to decode.
} else {
// Save remaining data for a later call.
if (!usePartialData_) {
usePartialData_ = true;
partialData_.position(0);
}
if (partialData_.buffer().position() + data.remaining() > net.named_data.jndn.util.Common.MAX_NDN_PACKET_SIZE) {
// Reset to read a new element on the next call.
usePartialData_ = false;
tlvStructureDecoder_ = new TlvStructureDecoder();
throw new EncodingException(
"The incoming packet exceeds the maximum limit Face.getMaxNdnPacketSize()");
}
partialData_.ensuredPut(data);
return;
}
}
}
/// <summary>
/// Create a new Blob from an existing ByteBuffer. IMPORTANT: If copy is
/// false, after calling this constructor, if you keep a pointer to the buffer
/// then you must treat it as immutable and promise not to change it.
/// </summary>
///
/// <param name="buffer"></param>
/// <param name="copy"></param>
public Blob(ByteBuffer buffer, bool copy)
{
this.haveHashCode_ = false;
if (buffer != null) {
if (copy) {
buffer_ = ILOG.J2CsMapping.NIO.ByteBuffer.allocate(buffer.remaining());
// Put updates buffer.position(), so save and restore it.
int savePosition = buffer.position();
buffer_.put(buffer);
buffer.position(savePosition);
buffer_.flip();
} else
buffer_ = buffer.slice();
} else
buffer_ = null;
}
