MilliSliceWriter.cc

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#include "dune-raw-data/Overlays/MilliSliceWriter.hh"
#include "cetlib_except/exception.h"

dune::MilliSliceWriter::
MilliSliceWriter(uint8_t* address, uint32_t max_size_bytes) :
    MilliSlice(address), max_size_bytes_(max_size_bytes)
{
  header_()->version = 1;
  header_()->millislice_size = sizeof(Header);
  header_()->microslice_count = 0;
}

std::shared_ptr<dune::MicroSliceWriter>
dune::MilliSliceWriter::reserveMicroSlice(uint32_t ms_max_bytes)
{
  // finalize the most recent MicroSlice, in case that hasn't
  // already been done
  finalizeLatestMicroSlice_();

  // test if this new MicroSlice could overflow our maximum size
  if ((size() + ms_max_bytes) > max_size_bytes_) {
    throw cet::exception("MilliSliceWriter") << "Slice overflow error";
  }

  // create the next MicroSlice in our buffer, and update our
  // counters to include the new MicroSlice
  uint8_t* ms_ptr = data_(header_()->microslice_count);
  latest_microslice_ptr_.reset(new MicroSliceWriter(ms_ptr, ms_max_bytes));
  ++(header_()->microslice_count);
  header_()->millislice_size += ms_max_bytes;
  return latest_microslice_ptr_;
}

int32_t dune::MilliSliceWriter::finalize()
{
  // first, we need to finalize the last MicroSlice, in case that
  // hasn't already been done
  finalizeLatestMicroSlice_();

  // next, we update our maximum size so that no more MicroSlices
  // can be added
  int32_t size_diff = max_size_bytes_ - header_()->millislice_size;
  max_size_bytes_ = header_()->millislice_size;
  return size_diff;
}

void dune::MilliSliceWriter::finalizeLatestMicroSlice_()
{
  if (header_()->microslice_count > 0 &&
      latest_microslice_ptr_.get() != 0) {
    int size_change = latest_microslice_ptr_->finalize();
    header_()->millislice_size -= size_change;
  }
}

dune::MilliSliceWriter::Header* dune::MilliSliceWriter::header_()
{
  return reinterpret_cast<Header *>(buffer_);
}

uint8_t* dune::MilliSliceWriter::data_(int index)
{
  uint8_t* ms_ptr = buffer_ + sizeof(Header);
  for (int idx = 0; idx < index; ++idx) {
    MicroSlice tmp_ms(ms_ptr);
    ms_ptr += tmp_ms.size();
  }
  return ms_ptr;
}