read_frame_legacy_root.cpp

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#include "read_test.h"
 
#include "podio/Frame.h"
#include "podio/ROOTLegacyReader.h"
 
#include <iostream>
 
int main() {
  auto reader = podio::ROOTLegacyReader();
  try {
    reader.openFile("example.root");
  } catch (const std::runtime_error& e) {
    std::cout << "File could not be opened, aborting." << std::endl;
    return 1;
  }
 
  if (reader.currentFileVersion() != podio::version::build_version) {
    std::cerr << "The podio build version could not be read back correctly. "
              << "(expected:" << podio::version::build_version << ", actual: " << reader.currentFileVersion() << ")"
              << std::endl;
    return 1;
  }
 
  if (reader.getEntries("events") != 2000) {
    std::cerr << "Could not read back the number of events correctly. "
              << "(expected:" << 2000 << ", actual: " << reader.getEntries("events") << ")" << std::endl;
    return 1;
  }
 
  for (size_t i = 0; i < reader.getEntries("events"); ++i) {
    const auto frame = podio::Frame(reader.readNextEntry("events"));
    processEvent(frame, i, reader.currentFileVersion());
  }
 
  // Reading specific entries
  {
    auto frame = podio::Frame(reader.readEntry("events", 4));
    processEvent(frame, 4, reader.currentFileVersion());
 
    auto nextFrame = podio::Frame(reader.readNextEntry("events"));
    processEvent(nextFrame, 5, reader.currentFileVersion());
 
    auto previousFrame = podio::Frame(reader.readEntry("events", 2));
    processEvent(previousFrame, 2, reader.currentFileVersion());
  }
 
  return 0;
}