-//$$CDS-header$$
-
-#ifndef __CDS_REFCOUNTER_H
-#define __CDS_REFCOUNTER_H
-
-/*
- Refernce counting primitives
-
- Editions:
-*/
-
-#include <cds/algo/atomic.h>
-
-namespace cds {
-
- /// Simple reference counter
- /**
- Thread-safe reference counter build on atomic primitives.
- \p T is one of integer types
- */
- template <typename T>
- class ref_counter
- {
- atomics::atomic<T> m_nRefCount ; ///< The reference counter
-
- public:
- typedef T ref_counter_type ; ///< The reference counter type
-
- public:
- /// Construct reference counter with specified value \p initValue
- ref_counter( T initValue = 0 ) CDS_NOEXCEPT
- : m_nRefCount(initValue)
- {}
-
- /// Get current value of reference counter.
- T value() const CDS_NOEXCEPT
- {
- return m_nRefCount.load( atomics::memory_order_relaxed );
- }
-
- /// Current value of reference counter
- operator T() const CDS_NOEXCEPT
- {
- return value();
- }
-
- /// Atomic increment
- void inc() CDS_NOEXCEPT
- {
- m_nRefCount.fetch_add( 1, atomics::memory_order_relaxed );
- }
-
- /// Atomic decrement. Return \p true if reference counter is 0, otherwise \p false
- bool dec() CDS_NOEXCEPT
- {
- if ( m_nRefCount.fetch_sub( 1, atomics::memory_order_relaxed ) == 1 ) {
- atomics::atomic_thread_fence( atomics::memory_order_release );
- return true;
- }
- return false;
- }
-
- /// Atomic increment
- void operator ++() CDS_NOEXCEPT
- {
- inc();
- }
-
- /// Atomic decrement
- bool operator--() CDS_NOEXCEPT
- {
- return dec();
- }
- };
-
- /// Signed 32bit reference counter
- typedef ref_counter<int32_t> signed_ref_counter;
-
- /// Unsigned 32bit reference counter
- typedef ref_counter<uint32_t> unsigned_ref_counter;
-
-} // namespace cds
-
-#endif // #ifndef __CDS_REFCOUNTER_H
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