/* The following code example is taken from the book * "C++ Templates - The Complete Guide" * by David Vandevoorde and Nicolai M. Josuttis, Addison-Wesley, 2002 * * (C) Copyright David Vandevoorde and Nicolai M. Josuttis 2002. * Permission to copy, use, modify, sell and distribute this software * is granted provided this copyright notice appears in all copies. * This software is provided "as is" without express or implied * warranty, and with no claim as to its suitability for any purpose. */#include <stddef.h>  // for the definition of size_t#include "allocator.hpp"class SimpleReferenceCount {  private:    size_t* counter;    // the allocated counter  public:    SimpleReferenceCount () {        counter = NULL;    }    // default copy constructor and copy-assignment operator    // are fine in that they just copy the shared counter  public:    // allocate the counter and initialize its value to one:    template<typename T> void init (T*) {        counter = alloc_counter();        *counter = 1;    }    // dispose of the counter:    template<typename T> void dispose (T*) {        dealloc_counter(counter);    }    // increment by one:    template<typename T> void increment (T*) {        ++*counter;    }        // decrement by one:    template<typename T> void decrement (T*) {        --*counter;    }    // test for zero:    template<typename T> bool is_zero (T*) {        return *counter == 0;    }};