67 lines
1.5 KiB
C
67 lines
1.5 KiB
C
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#ifndef FORTRAN_PARSER_REFERENCE_COUNTED_H_
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#define FORTRAN_PARSER_REFERENCE_COUNTED_H_
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// A template class of smart pointers to objects with their own
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// reference counting object lifetimes that's lighter weight
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// than std::shared_ptr<>. Not thread-safe.
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namespace Fortran {
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namespace parser {
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template<typename A> class ReferenceCounted {
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public:
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ReferenceCounted() {}
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void TakeReference() { ++references_; }
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void DropReference() {
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if (--references_ == 0) {
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delete static_cast<A*>(this);
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}
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}
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private:
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int references_{0};
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};
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template<typename A> class CountedReference {
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public:
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using type = A;
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CountedReference() {}
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CountedReference(type *m) : p_{m} { Take(); }
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CountedReference(const CountedReference &c) : p_{c.p_} { Take(); }
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CountedReference(CountedReference &&c) : p_{c.p_} { c.p_ = nullptr; }
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CountedReference &operator=(const CountedReference &c) {
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Drop();
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p_ = c.p_;
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Take();
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return *this;
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}
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CountedReference &operator=(CountedReference &&c) {
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Drop();
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p_ = c.p_;
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c.p_ = nullptr;
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return *this;
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}
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~CountedReference() { Drop(); }
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operator bool() const { return p_ != nullptr; }
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type *get() const { return p_; }
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type &operator*() const { return *p_; }
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type *operator->() const { return p_; }
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private:
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void Take() {
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if (p_) {
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p_->TakeReference();
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}
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}
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void Drop() {
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if (p_) {
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p_->DropReference();
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p_ = nullptr;
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}
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}
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type *p_{nullptr};
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};
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} // namespace parser
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} // namespace Fortran
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#endif // FORTRAN_PARSER_REFERENCE_COUNTED_H_
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