YiLocklessCache.h

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// © You i Labs Inc. 2000-2017. All rights reserved.
#ifndef _YI_LOCKLESS_CACHE_H_
#define _YI_LOCKLESS_CACHE_H_

#include "framework/YiPredef.h"
#include "utility/YiUtilities.h"

#define YI_LOCKLESS_CACHE_SIZE 3 // Triple Buffer

template<typename YI_CACHE_TYPE>
class CYILocklessCache
{
    YI_CACHE_TYPE m_cacheLists[YI_LOCKLESS_CACHE_SIZE];

    mutable volatile uint32_t m_uCurrentReadIndex;
    mutable volatile uint32_t m_uNextReadIndex;

public:

    inline CYILocklessCache() :
            m_uCurrentReadIndex(0), m_uNextReadIndex(0)
    {
    }

    inline bool HasNextRead() const
    {
        return m_uCurrentReadIndex != m_uNextReadIndex;
    }

    inline const YI_CACHE_TYPE &Read() const
    {
        m_uCurrentReadIndex = m_uNextReadIndex;
        return m_cacheLists[m_uCurrentReadIndex];
    }

    inline void Write(const YI_CACHE_TYPE &rData)
    {
        volatile uint32_t m_uUnusedIndex = 0;
        while((m_uUnusedIndex == m_uNextReadIndex || m_uUnusedIndex == m_uCurrentReadIndex)) ++m_uUnusedIndex;
        m_cacheLists[m_uUnusedIndex] = rData;
        YI_SWAP(m_uNextReadIndex, m_uUnusedIndex);
    }
};

#endif /* _YI_LOCKLESS_CACHE_H_ */