File content as of revision 5:5362073f2689:

#pragma once 

template <class T>
class Pipe
{
private:
    inline int _inc(int i, int n = 1)
    {
        i += n;
        if (i >= s)
            i -= s;
        return i;
    }
public:
    Pipe(int n, T* p = NULL)
    {
        a = p ? NULL : new T[n];
        r = 0;
        w = 0;
        b = p ? p : a;
        s = n;
    }    
    virtual ~Pipe()
    {
        if (a) 
            delete [] a;
    }
    // writing thread
    bool writeable(void) // = not full
    {
        int i = _inc(w);
        return (i = r);
    }
    int free(void)      // number of elements that can be added
    {
        int t = r - w;
        if (t <= 0)
            t += s;
        return t - 1;
    }
    void putc(T c)
    {
        int i = w;
        int j = i;
        i = _inc(i);
        //assert(i != r);
        b[j] = c;
        w = i;   
    }
    int put(T* p, int n)
    {
        int f = free();
        if (f < n)
            n = f;
        if (n)
        {
            int m = s - w;
            if (m > n)
                m = n;
            memcpy(&b[w], &p[0], m);
            int t = n - m;
            if (t)
            {
                memcpy(&b[0], &p[m], t);
                w = t;
            }
            else 
                w += m; 
        }
        return n;
    }
    // reading thread 
    // --------------------------------------------------------
    //! check if there are any values available
    bool readable(void) // = not empty
    {
        return (r != w);
    }
    //! get the number of values avialable in the buffer 
    virtual int size(void)
    {
        int t = w - r;
        if (t < 0)
            t += s;
        return t;
    }
    //! get a value from buffer (this function will block if no values available)
    T getc(void)
    {
        //while (r == w)
        //    /* just wait until w changes*/;
        T t = b[r];
        r = _inc(r);
        return t;
    }
    // get values from buffer (if the buffer has less values, only the values avilable are returned)
    virtual int get(T* p, int n)
    {
        int f = size();
        if (f < n)
            n = f;
        if (n)
        {
            int m = s - r;
            if (m > n)
                m = n;
            memcpy(&p[0], &b[r], m);
            int t = n - m;
            if (t)
            {
                memcpy(&p[m] ,&b[0], t);
                r = t;
            }
            else 
                r += m;
        }
        return n;
    }
    // the following functions are useful if you like to inspect or parse the buffer
    virtual int start(void) { o = r; return size(); }               // reset the parsing index and return the number of available elments
    virtual T next(void)    { T t = b[o]; o = _inc(o); return t; }  // get the next element and increment
    virtual void done(void) { r = o; }                              // commit the index 
    
private:
    // buffer
    T*            b; //!< buffer
    T*            a; //!< allocated buffer
    int           s; //!< size of buffer (s - 1) elements can be stored
    volatile int  w; //! write index 
    volatile int  r; //! read index 
    int           o; //! offest index used by parsing functions  
};