ringbuffer.h

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/* (c) Magnus Auvinen. See licence.txt in the root of the distribution for more information. */
/* If you are missing that file, acquire a complete release at teeworlds.com.                */
#ifndef ENGINE_SHARED_RINGBUFFER_H
#define ENGINE_SHARED_RINGBUFFER_H
 
#include <cstdlib>
#include <functional>
 
class CRingBufferBase
{
    class CItem
    {
    public:
        CItem *m_pPrev;
        CItem *m_pNext;
        int m_Free;
        int m_Size;
    };
 
    CItem *m_pBuffer;
 
    CItem *m_pProduce;
    CItem *m_pConsume;
 
    CItem *m_pFirst;
    CItem *m_pLast;
 
    int m_Size;
    int m_Flags;
 
    std::function<void(void *pCurrent)> m_PopCallback = nullptr;
 
    CItem *NextBlock(CItem *pItem);
    CItem *PrevBlock(CItem *pItem);
    CItem *MergeBack(CItem *pItem);
 
protected:
    void *Allocate(int Size);
 
    void *Prev(void *pCurrent);
    void *Next(void *pCurrent);
    void *First();
    void *Last();
 
    void Init(void *pMemory, int Size, int Flags);
    int PopFirst();
    void SetPopCallback(std::function<void(void *pCurrent)> PopCallback);
 
public:
    enum
    {
        // Will start to destroy items to try to fit the next one
        FLAG_RECYCLE = 1
    };
    static constexpr int ITEM_SIZE = sizeof(CItem);
 
    void Clear();
};
 
template<typename T>
class CTypedRingBuffer : public CRingBufferBase
{
public:
    T *Allocate(int Size) { return (T *)CRingBufferBase::Allocate(Size); }
    int PopFirst() { return CRingBufferBase::PopFirst(); }
    void SetPopCallback(const std::function<void(T *pCurrent)> &PopCallback)
    {
        CRingBufferBase::SetPopCallback([PopCallback](void *pCurrent) {
            PopCallback((T *)pCurrent);
        });
    }
 
    T *Prev(T *pCurrent) { return (T *)CRingBufferBase::Prev(pCurrent); }
    T *Next(T *pCurrent) { return (T *)CRingBufferBase::Next(pCurrent); }
    T *First() { return (T *)CRingBufferBase::First(); }
    T *Last() { return (T *)CRingBufferBase::Last(); }
};
 
template<typename T, int TSIZE, int TFLAGS = 0>
class CStaticRingBuffer : public CTypedRingBuffer<T>
{
    unsigned char m_aBuffer[TSIZE];
 
public:
    CStaticRingBuffer() { Init(); }
 
    void Init() { CRingBufferBase::Init(m_aBuffer, TSIZE, TFLAGS); }
};
 
template<typename T>
class CDynamicRingBuffer : public CTypedRingBuffer<T>
{
    unsigned char *m_pBuffer = nullptr;
 
public:
    CDynamicRingBuffer(int Size, int Flags = 0) { Init(Size, Flags); }
 
    ~CDynamicRingBuffer()
    {
        free(m_pBuffer);
    }
 
    void Init(int Size, int Flags)
    {
        free(m_pBuffer);
        m_pBuffer = static_cast<unsigned char *>(malloc(Size));
        CRingBufferBase::Init(m_pBuffer, Size, Flags);
    }
};
 
#endif