The hls::stream.size() method returns an
unsigned integer specifying the current number of elements the stream is holding. This
lets you check if there is data or how much data is in the channel prior to reading to
prevent stalls or deadlocks.
hls::stream.size() can be used to check if an
input FIFO is full, and an output FIFO is empty. While
hls::stream.empty() can only be applied to an input FIFO and
hls::stream.full() to an output FIFO.hls::stream<int> my_stream;
var = 16;
if (my_stream.size()>0) {
my_stream.read(var);
}The hls::stream.size() and hls::stream.capacity() methods enable advanced flow control
to write or read the stream only when there is specific amounts of space or data
available for the transaction. For example, before starting a read burst of size N, you
can check if there are N data items in the input stream so that the burst can complete
without stalling. For write bursts you can also check if there is enough space available
in an output stream to store the burst data without stalling.
if (instream.size() > N)
for(i=0, i<N; i++)
... = instream.read(); // will not block
To read only when the stream is full:
if (instream.size() == instream.capacity())
... = instream.read(); // read only if full
hls::stream.full() to check for this condition. The
following will not work:
if (instream.full())
... = instream.read();