1#ifndef APE_CIRCLEBUFFER_H
2#define APE_CIRCLEBUFFER_H
3
4class CCircleBuffer
5{
6public:
7
8    // construction / destruction
9    CCircleBuffer();
10    virtual ~CCircleBuffer();
11
12    // create the buffer
13    void CreateBuffer(int nBytes, int nMaxDirectWriteBytes);
14
15    // query
16    int MaxAdd();
17    int MaxGet();
18
19    // direct writing
20    inline unsigned char * GetDirectWritePointer()
21    {
22        // return a pointer to the tail -- note that it will always be safe to write
23        // at least m_nMaxDirectWriteBytes since we use an end cap region
24        return &m_pBuffer[m_nTail];
25    }
26
27    inline void UpdateAfterDirectWrite(int nBytes)
28    {
29        // update the tail
30        m_nTail += nBytes;
31
32        // if the tail enters the "end cap" area, set the end cap and loop around
33        if (m_nTail >= (m_nTotal - m_nMaxDirectWriteBytes))
34        {
35            m_nEndCap = m_nTail;
36            m_nTail = 0;
37        }
38    }
39
40    // get data
41    int Get(unsigned char * pBuffer, int nBytes);
42
43    // remove / empty
44    void Empty();
45    int RemoveHead(int nBytes);
46    int RemoveTail(int nBytes);
47
48private:
49
50    int m_nTotal;
51    int m_nMaxDirectWriteBytes;
52    int m_nEndCap;
53    int m_nHead;
54    int m_nTail;
55    unsigned char * m_pBuffer;
56};
57
58
59#endif // #ifndef APE_CIRCLEBUFFER_H
60