boost::uint32_t DecimationFilterSequentialIterator::readBufferImpl(PointBuffer& dstData)
{
// The client has asked us for dstData.getCapacity() points.
// We will read from our previous stage until we get that amount (or
// until the previous stage runs out of points).
boost::uint32_t numPointsNeeded = dstData.getCapacity();
assert(dstData.getNumPoints() == 0);
// set up buffer to be filled by prev stage
PointBuffer srcData(dstData.getSchemaLayout(), numPointsNeeded);
while (numPointsNeeded > 0)
{
// read from prev stage
const boost::uint64_t srcStartIndex = getPrevIterator().getIndex();
const boost::uint32_t numSrcPointsRead = getPrevIterator().read(srcData);
assert(numSrcPointsRead <= srcData.getNumPoints());
//assert(numSrcPointsRead <= numPointsNeeded);
// we got no data, and there is no more to get -- exit the loop
if (numSrcPointsRead == 0) break;
// copy points from src (prev stage) into dst (our stage),
// based on the CropFilter's rules (i.e. its bounds)
const boost::uint32_t numPointsAdded = m_filter.processBuffer(dstData, srcData, srcStartIndex);
numPointsNeeded -= numPointsAdded;
//printf(".");fflush(stdout);
}
const boost::uint32_t numPointsAchieved = dstData.getNumPoints();
return numPointsAchieved;
}
