IterWithDict.cc

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#include "FWCore/Utilities/interface/IterWithDict.h"
#include <cassert>

namespace edm {

  void IterWithDictBase::advance() {
    if (atEnd_) {
      return;
    }
    TObject* obj = iter_.Next();
    if (obj == nullptr) {
      atEnd_ = true;
    }
  }

  TIter const& IterWithDictBase::iter() const { return iter_; }

  IterWithDictBase::IterWithDictBase() : iter_(static_cast<TList*>(nullptr)), atEnd_(true) {
    // This ctor is used by the framework for the end of a range,
    // or for any type that does not have a TClass.
    // An iterator constructed by this ctor must not be used
    // as the left hand argument of operator!=().
  }

  IterWithDictBase::IterWithDictBase(TList* list) : iter_(list), atEnd_(false) {
    // With a TIter, you must call Next() once to point to the first element.
    TObject* obj = iter_.Next();
    if (obj == nullptr) {
      atEnd_ = true;
    }
  }

  bool IterWithDictBase::operator!=(IterWithDictBase const& rhs) const {
    // The special cases are needed because TIter::operator!=()
    // dereferences a null pointer (i.e. segfaults) if the left hand TIter
    // was constucted with a nullptr argument (the first constructor above).
    if (atEnd_ != rhs.atEnd_) {
      // one iterator at end, but not both
      return true;
    }
    if (atEnd_) {
      // both iterators at end
      return false;
    }
    // neither iterator at end
    return iter_ != rhs.iter_;
  }

}  // namespace edm